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1.
Medicina (Kaunas) ; 60(3)2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38541207

RESUMO

Background and Objectives: Burn surgery on the hands is a difficult procedure due to the complex anatomy and fragility of the area. Enzymatic debridement has been shown to effectively remove burn eschar while minimizing damage to the surrounding tissue and has therefore become a standard procedure in many burn centers worldwide over the past decade. However, surprisingly, our recent literature review showed limited valid data on the long-term scarring after the enzymatic debridement of the hands. Therefore, we decided to present our study on this topic to fill this gap. Materials and Methods: This study analyzed partial-thickness to deep dermal burns on the hands that had undergone enzymatic debridement at least 12 months prior. Objective measures, like flexibility, trans-epidermal water loss, erythema, pigmentation, and microcirculation, were recorded and compared intraindividually to the uninjured skin in the same area of the other hand to assess the regenerative potential of the skin after EDNX. The subjective scar quality was evaluated using the patient and observer scar assessment scale (POSAS), the Vancouver Scar Scale (VSS), and the "Disabilities of the Arm, Shoulder, and Hand" (DASH) questionnaire and compared interindividually to a control group of 15 patients who had received traditional surgical debridement for hand burns of the same depth. Results: Between January 2014 and December 2015, 31 hand burns in 28 male and 3 female patients were treated with enzymatic debridement. After 12 months, the treated wounds showed no significant differences compared to the untreated skin in terms of flexibility, trans-epidermal water loss, pigmentation, and skin surface. However, the treated wounds still exhibited significantly increased blood circulation and erythema compared to the untreated areas. In comparison to the control group who received traditional surgical debridement, scarring was rated as significantly superior. Conclusions: In summary, it can be concluded that the objective skin quality following enzymatic debridement is comparable to that of healthy skin after 12 months and subjectively fares better than that after tangential excision. This confirms the superiority of enzymatic debridement in the treatment of deep dermal burns of the hand and solidifies its position as the gold standard.


Assuntos
Queimaduras , Cicatriz , Humanos , Masculino , Feminino , Cicatriz/cirurgia , Cicatrização , Desbridamento/métodos , Bromelaínas , Queimaduras/complicações , Queimaduras/cirurgia , Eritema , Água
2.
Wound Repair Regen ; 31(5): 663-670, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37534628

RESUMO

Chronic wounds remain a therapeutic and financial challenge for physicians and the health care systems. Innovative, inexpensive and effective treatment methods would be of immense value. The sublesional fat grafting could be such treatment, although effectiveness and safety have only been assessed in a few randomised clinical trials. The fat graft was obtained by liposuction, washed with the Coleman method and then injected sublesional and into the wound margins after surgical debridement. For the control group, saline solution was used instead of fat. The primary endpoint was to determine the wound size reduction in both groups. The wounds were measured preoperatively, intraoperatively and 3, 7, 21 and 60 days after the intervention. A p-value of <0.05 was considered significant. Furthermore, histology and microbiology of the wounds and pain were assessed. A temporary effect of the treatment was observed after 14 and 21 days. The wound size reduction was significantly larger in the intervention group, whereas after 60 days, no significant difference was detected between both groups. No adverse events could be reported and the pain level was almost equal in the control and intervention group. Sublesional fat grafting temporarily enhanced healing of chronic wounds. The procedure was safe and the pain level was low. Repeated interventions could lead to complete wound closure, which should be determined in future studies.


Assuntos
Úlcera da Perna , Úlcera Varicosa , Humanos , Cicatrização , Estudos Prospectivos , Úlcera Varicosa/terapia , Úlcera da Perna/cirurgia , Tecido Adiposo , Dor
3.
Proc Natl Acad Sci U S A ; 117(21): 11811-11819, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32393641

RESUMO

"Growing old" is the most common cause of hearing loss. Age-related hearing loss (ARHL) (presbycusis) first affects the ability to understand speech in background noise, even when auditory thresholds in quiet are normal. It has been suggested that cochlear denervation ("synaptopathy") is an early contributor to age-related auditory decline. In the present work, we characterized age-related cochlear synaptic degeneration and hair cell loss in mice with enhanced α9α10 cholinergic nicotinic receptors gating kinetics ("gain of function" nAChRs). These mediate inhibitory olivocochlear feedback through the activation of associated calcium-gated potassium channels. Cochlear function was assessed via distortion product otoacoustic emissions and auditory brainstem responses. Cochlear structure was characterized in immunolabeled organ of Corti whole mounts using confocal microscopy to quantify hair cells, auditory neurons, presynaptic ribbons, and postsynaptic glutamate receptors. Aged wild-type mice had elevated acoustic thresholds and synaptic loss. Afferent synapses were lost from inner hair cells throughout the aged cochlea, together with some loss of outer hair cells. In contrast, cochlear structure and function were preserved in aged mice with gain-of-function nAChRs that provide enhanced olivocochlear inhibition, suggesting that efferent feedback is important for long-term maintenance of inner ear function. Our work provides evidence that olivocochlear-mediated resistance to presbycusis-ARHL occurs via the α9α10 nAChR complexes on outer hair cells. Thus, enhancement of the medial olivocochlear system could be a viable strategy to prevent age-related hearing loss.


Assuntos
Envelhecimento/fisiologia , Cóclea , Células Ciliadas Auditivas Externas , Presbiacusia , Complexo Olivar Superior , Animais , Cóclea/fisiologia , Cóclea/fisiopatologia , Potenciais Evocados Auditivos do Tronco Encefálico/fisiologia , Retroalimentação Fisiológica/fisiologia , Células Ciliadas Auditivas Externas/citologia , Células Ciliadas Auditivas Externas/fisiologia , Camundongos , Emissões Otoacústicas Espontâneas/fisiologia , Presbiacusia/fisiopatologia , Presbiacusia/prevenção & controle , Complexo Olivar Superior/citologia , Complexo Olivar Superior/fisiologia
4.
J Wound Care ; 32(5): 284-290, 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-37094928

RESUMO

OBJECTIVE: Necrotising fasciitis (NF) is a quickly progressing and potentially life-threatening infection, involving the fascia and subcutaneous tissues. The diagnosis of this disease is challenging, especially due to a lack of specific clinical signs. In order to ensure a better and quicker identification of NF patients, a laboratory risk indicator score has been developed for NF (LRINEC). A variant has widened this score by adding clinical parameters (modified LRINEC). This study shows current outcomes of NF and compares the two scoring systems. METHODS: This study was conducted between 2011 and 2018, and included patient demographics, clinical presentations, sites of infection, comorbidities, microbiological and laboratory findings, antibiotic therapies and LRINEC as well as modified LRINEC scores. The primary outcome was in-hospital mortality. RESULTS: A cohort of 36 patients, diagnosed with NF, were included in this study. The mean hospital stay was 56 days (±38.2 days). The mortality rate in the cohort was 25%. The sensitivity of the LRINEC score was 86%. Calculation of the modified LRINEC score showed an improvement of the sensitivity to 97%. The average LRINEC score and modified LRINEC score for patients who died and who survived were equal (7.4 versus 7.9 and 10.4 versus 10.0, respectively). CONCLUSION: The mortality rate of NF remains high. The modified LRINEC score increased the sensitivity in our cohort to 97%, and this scoring system could be supportive in the diagnosis of NF for early surgical debridement.


Assuntos
Fasciite Necrosante , Humanos , Fasciite Necrosante/diagnóstico , Estudos Retrospectivos , Fatores de Risco
5.
Gesundheitswesen ; 85(8-09): 697-705, 2023 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-36720235

RESUMO

AIM OF THE STUDY: For female and male physicians of the clinical-academic mid-level staff, working conditions as well as the attitude towards profession and career play a decisive role. For years, there has been an increasing proportion of women in medicine. Despite this increase, a significant sex incongruence is still evident, especially in academic medicine. The aim of this work was to analyze current opinions of female and male physicians on sex-related aspects for career. METHODS: By means of an online survey, medical mid-level staff from university and peripheral hospitals were asked about professional biographical as well as career-related topics and the data analyzed in terms of the sexes. RESULTS: Compared to their male counterparts, female physicians had lower career goals and mainly aimed to qualify as senior physicians. Women planned to have families and raise children earlier in their careers. Men were more likely to have their professional careers in mind during the same time period. Although only just under 47% of respondents considered an academic career to be worthwhile, 65% continued to rate the acquisition of an academic title highly. When evaluating equal treatment by superiors, female physicians tended to feel disadvantaged in their professional careers compared to male physicians. Thus, physicians rated the treatment by their respective superiors as characterized by the quality of the work (44% for both genders of superiors) or dependent on sympathy (female superiors 30%; male superiors 24%). Female physicians, however, saw a preference for male colleagues in 37% of male superiors. CONCLUSION: Despite a significantly larger proportion of women in medicine for decades, there is still an incongruence in sexes in favor of men in management positions. The professional and private goals of women and men differ significantly depending on their age decade. The academic career per se is increasingly losing importance, although the acquisition of academic degrees still seems to be desirable. Therefore, to improve the future of academic medicine, significant structural changes are needed to enable projectable career paths (e. g., tenure track, assistant professorship, young medical professionals model) for mid-level academic staff.


Assuntos
Médicas , Médicos , Criança , Humanos , Masculino , Feminino , Objetivos , Escolha da Profissão , Alemanha , Inquéritos e Questionários , Mobilidade Ocupacional
6.
Medicina (Kaunas) ; 59(10)2023 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-37893592

RESUMO

Background and Objectives: Good scar management in burn care is essential. Nevertheless, there are no consistent recommendations regarding moisturizers for scar management. Our aim was to investigate and compare the effects of commonly used products on normal skin and burn scars. Materials and Methods: A total of 30 skin-healthy (control group) and 12 patients with burn scars were included in this study. For an intraindividual comparison, each participant received creams consisting of dexpanthenol (P), aloe vera (A), and a natural plant oil (O) with instructions to apply them daily to a previously defined area for at least 28 days. Objective scar evaluation was performed with Visioscan®; Tewameter®; Cutometer®, and the Oxygen To See® device. Subjective evaluation was performed with an "application" questionnaire, the Patient and Observer Scar Assessment Scale (POSAS), and with the "best of three" questionnaire. Results: After (A) a high trend of amelioration of +30%, TEWL was detected on the scar area. Blood flow increased slightly on healthy skin areas after (A) application to +104%. The application of (A) on healthy skin demonstrated a positive effect on the parameters of scaliness (+22%, p < 0.001), softness (+14%, p = 0.046), roughness R1 (+16%, p < 0.001) and R2 (+17%, p = 0.000), volume (+22%, p < 0.001), and surface area (+7%, p < 0.001) within the control group. After (P), a significant improvement of the baseline firmness parameter of +14.7% was detected (p = 0.007). (P) also showed a beneficial effect on the parameters of R1 (+7%, p = 0.003), R2 (+6%, p = 0.001), and volume (+17%, p = 0.001). (O) lead to a statistically significant improvement of volume (+15%, p = 0.009). Overall, most study participants stated (A) to be the "best of three". Conclusions: (A) performed statistically best, and is a well-tolerated moisturizing product. However, further quantitative studies are needed to provide statistically significant clarification for uniform recommendations for scar therapy.


Assuntos
Aloe , Queimaduras , Humanos , Cicatriz/tratamento farmacológico , Cicatriz/etiologia , Pele/patologia
7.
Int Wound J ; 19(1): 178-187, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33973387

RESUMO

Currently, many dressings are commercially available for the treatment of burn wounds. Some of these wound dressings remain on the wound, prevent painful dressing changes, and reduce tissue scarring. Nevertheless, still a wound dressing that is cost-effective, produces good wound healing properties, and has a high patient satisfaction is needed. Standard care of superficial burn wounds differs between burn centres. This study aimed to determine a dressing with easy appliance, accurate pain control, favourable outcome, and cost-effectiveness. Therefore, we compared the widely used but expensive Suprathel with the rather new but much cheaper Dressilk in the clinical setting. In a prospective clinical study, the healing of partial thickness burn wounds after simultaneous treatment with Suprathel and Dressilk was examined in 20 patients intra-individually. During wound healing, pain, infection, exudation, and bleeding were evaluated. A subjective scar evaluation was performed using the Patient and Observer Scar Scale. Both dressings were easy to apply, remained on the wound in place, and were gradually cut back as reepithelisation proceeded and showed similar times to wound closure. Dressing changes were not necessary, and neither infections nor bleeding was detected. Overall exudation and pain were highest in the beginning but declined during the wound-healing phase without significant differences. In the follow-up scar evaluation after 12 months, patients reported overall high satisfaction. Overall, the modern dressings Suprathel and Dressilk (solely made out of pure silk) led to safe wound healing without infection and rapidly reduced pain. There was no need for dressing changes, and they had similar clinical outcomes in scar evaluation. Therefore, both dressings seem to be ideal for the treatment of superficial burns. Because acquisition costs remain one of the main factors in the treatment of burns, Dressilk, which is ~20 times cheaper than Suprathel, remains a good option for the treatment of partial thickness burns.


Assuntos
Queimaduras , Pele Artificial , Bandagens , Queimaduras/terapia , Humanos , Estudos Prospectivos , Seda
8.
Int Wound J ; 19(4): 782-790, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34390204

RESUMO

Among the available dressings for partial-thickness burn wound treatment, SUPRATHEL has shown good usability and effectiveness for wound healing and patient comfort and has been used in many burn centres in the last decade. Recently, bacterial nanocellulose (BNC) has become popular for the treatment of wounds, and many studies have demonstrated its efficacy. epicitehydro , consisting of BNC and 95% water, is a promising product and has recently been introduced in numerous burn centres. To date, no studies including direct comparisons to existing products like SUPRATHEL have been conducted. Therefore, we aimed to compare epicitehydro to SUPRATHEL in the treatment of partial-thickness burns. Twenty patients with partial-thickness burns affecting more than 0.5% of their total body surface area (TBSA) were enrolled in this prospective, unicentric, open, comparative, intra-individual clinical study. After debridement, the wounds were divided into two areas: one was treated with SUPRATHEL and the other with epicitehydro . Wound healing, infection, bleeding, exudation, dressing changes, and pain were documented. The quality of the scar tissue was assessed subjectively using the Patient and Observer Scar Scale. Wound healing in patients with a mean TBSA of 9.2% took 15 to 16 days for both treatments without dressing changes. All wounds showed minimal exudation, and patients reported decreased pain with the only significant difference between the two dressings on day 1. No infection or bleeding occurred in any of the wounds. Regarding scar evaluation, SUPRATHEL and epicitehydro did not differ significantly. Both wound dressings were easy to use, were highly flexible, created a safe healing environment, had similar effects on pain reduction, and showed good cosmetic and functional results without necessary dressing changes. Therefore, epicitehydro can be used as an alternative to SUPRATHEL for the treatment of partial-thickness burn wounds.


Assuntos
Queimaduras , Lesões dos Tecidos Moles , Bandagens , Queimaduras/terapia , Cicatriz , Humanos , Dor , Conforto do Paciente , Poliésteres , Estudos Prospectivos , Cicatrização
9.
Medicina (Kaunas) ; 58(11)2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36363504

RESUMO

Background and Objectives: Scar formation after burn trauma has a significant impact on the quality of life of burn patients. Hypertrophic scars or keloids can be very distressing to patients due to potential pain, functional limitations, or hyper- or hypopigmentation. In a previous study comparing Suprathel® and the new and cheaper dressing epicitehydro®, we were able to show that pain reduction, exudation, and time until wound-healing of partial-thickness burn wounds were similar, without any documented infections. No study exists that objectively measures and compares skin and scar quality after treatment with Suprathel® and epicitehydro® at present. Materials and Methods: In this study, the scar quality of 20 patients who had been treated with Suprathel® and epicitehydro® was objectively assessed using the Cutometer®, Mexameter®, and Tewameter®, as well as subjectively with the Patient and Observer Scar Assessment Scale, 3, 6, and 12 months after burn injury. Results: In all performed measurements, no significant differences were detected in scar formation after treatment of partial-thickness burn wounds with the two dressings. Conclusions: Both the newer and less expensive wound-dressing epicitehydro® and the well-known wound-dressing Suprathel® resulted in stable wound closure and showed good cosmetic results in the follow-up examinations.


Assuntos
Queimaduras , Cicatriz , Humanos , Cicatriz/etiologia , Transplante de Pele/métodos , Qualidade de Vida , Queimaduras/complicações , Queimaduras/terapia , Bandagens , Dor
10.
Proc Natl Acad Sci U S A ; 115(9): E2095-E2104, 2018 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-29439202

RESUMO

During a critical developmental period, cochlear inner hair cells (IHCs) exhibit sensory-independent activity, featuring action potentials in which Ca2+ ions play a fundamental role in driving both spiking and glutamate release onto synapses with afferent auditory neurons. This spontaneous activity is controlled by a cholinergic input to the IHC, activating a specialized nicotinic receptor with high Ca2+ permeability, and coupled to the activation of hyperpolarizing SK channels. The mechanisms underlying distinct excitatory and inhibitory Ca2+ roles within a small, compact IHC are unknown. Making use of Ca2+ imaging, afferent auditory bouton recordings, and electron microscopy, the present work shows that unusually high intracellular Ca2+ buffering and "subsynaptic" cisterns provide efficient compartmentalization and tight control of cholinergic Ca2+ signals. Thus, synaptic efferent Ca2+ spillover and cross-talk are prevented, and the cholinergic input preserves its inhibitory signature to ensure normal development of the auditory system.


Assuntos
Sinalização do Cálcio , Cálcio/metabolismo , Cóclea/fisiologia , Células Ciliadas Auditivas Internas/citologia , Sinapses/fisiologia , Acetilcolina/farmacologia , Potenciais de Ação , Animais , Vias Auditivas/fisiologia , Estimulação Elétrica , Feminino , Ácido Glutâmico/metabolismo , Audição , Masculino , Camundongos , Neurônios/fisiologia , Técnicas de Patch-Clamp , Canais de Potássio Cálcio-Ativados/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores Nicotínicos/fisiologia , Transdução de Sinais
11.
Medicina (Kaunas) ; 57(4)2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33915729

RESUMO

BACKGROUND: Integrative medicine focuses on the human being as a whole-on the body, mind, and spirit-to achieve optimal health and healing. As a synthesis of conventional and complementary treatment options, integrative medicine combines the pathological with the salutogenetic approach of therapy. The aim is to create a holistic system of medicine for the individual. So far, little is known about its role in plastic surgery. HYPOTHESIS: We hypothesize that integrative medicine based on a conventional therapy with additional anthroposophic therapies is very potent and beneficial for plastic surgery patients. Evaluation and consequence of the hypothesis: Additional anthroposophic pharmacological and non-pharmacological treatments are promising for all areas of plastic surgery. We are convinced that our specific approach will induce further clinical trials to underline its therapeutic potential.


Assuntos
Medicina Integrativa , Procedimentos de Cirurgia Plástica , Cirurgia Plástica , Humanos
12.
Medicina (Kaunas) ; 56(12)2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33348927

RESUMO

Background and Objective: The use of plant-based products for burn treatment dates back to 1600 BC. Enzymatic debridement, which can be achieved as non-surgical or conservative debridement, has recently gained increasing attention. Several reviews have been published thus far. However, there has been no historical article including the achievements of the last 20 years, and this is the first review to present the achievements made in the field of enzymatic debridement in the last 20 years. This study aimed to present a historical overview of the development of enzymatic debridement until the present day. Methods: Enzymes from bacteria and plants were initially used for full-thickness burn treatment; however, they did not gain attention. Papain-derived products were the first plant-based products used for enzymatic debridement. Sutilains gained broad use in the 70s and 80s but came off market in the 1990s. Bromelain has been used for burn treatment owing to its strong debriding properties. NexoBrid™ is used as a minimally invasive approach for enzymatic debridement of deep dermal burns. However, its use has been limited due to commercially available bromelain and the presence of four distinct cysteine proteinases. NexoBrid™ involves faster eschar removal together with reduced blood loss, leading to improved long-term outcomes. However, research on nonoperative enzymatic debridement of burns has taken decades and is still ongoing. Results: Overall, the results of our study indicate that necrectomy, which has been used for a long time, remains the standard of care for burns. However, enzymatic debridement has several advantages, such as faster eschar removal, reduced blood loss, and reduced need for skin grafting, especially in cases of facial and hand burns. Enzymatic debridement cannot replace surgical intervention, as the enzyme only works on the surface of the eschar. Enzymatic debridement is not recommended in the early phase of scald burns. Conclusions: Enzymatic debridement has become an integral part of burn therapy and the standard of care in specific burn centers.


Assuntos
Padrão de Cuidado , Cicatrização , Desbridamento , Humanos , Transplante de Pele
13.
J Neurosci ; 38(25): 5677-5687, 2018 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-29789373

RESUMO

Until postnatal day (P) 12, inner hair cells of the rat cochlea are invested with both afferent and efferent synaptic connections. With the onset of hearing at P12, the efferent synapses disappear, and afferent (ribbon) synapses operate with greater efficiency. This change coincides with increased expression of voltage-gated potassium channels, the loss of calcium-dependent electrogenesis, and the onset of graded receptor potentials driven by sound. The transient efferent synapses include near-membrane postsynaptic cisterns thought to regulate calcium influx through the hair cell's α9-containing and α10-containing nicotinic acetylcholine receptors. This influx activates small-conductance Ca2+-activated K+ (SK) channels. Serial-section electron microscopy of inner hair cells from two 9-d-old (male) rat pups revealed many postsynaptic efferent cisterns and presynaptic afferent ribbons whose average minimal separation in five cells ranged from 1.1 to 1.7 µm. Efferent synaptic function was studied in rat pups (age, 7-9 d) of either sex. The duration of these SK channel-mediated IPSCs was increased by enhanced calcium influx through L-type voltage-gated channels, combined with ryanodine-sensitive release from internal stores-presumably the near-membrane postsynaptic cistern. These data support the possibility that inner hair cell calcium electrogenesis modulates the efficacy of efferent inhibition during the maturation of inner hair cell synapses.SIGNIFICANCE STATEMENT Strict calcium buffering is essential for cellular function. This problem is especially acute for compact hair cells where increasing cytoplasmic calcium promotes the opposing functions of closely adjoining afferent and efferent synapses. The near-membrane postsynaptic cistern at efferent synapses segregates synaptic calcium signals by acting as a dynamic calcium store. The hair cell serves as an informative model for synapses with postsynaptic cisterns (C synapses) found in central neurons.


Assuntos
Sinalização do Cálcio/fisiologia , Cóclea/inervação , Células Ciliadas Auditivas Internas/citologia , Células Ciliadas Auditivas Internas/fisiologia , Sinapses/fisiologia , Animais , Animais Recém-Nascidos , Canais de Cálcio Tipo L/metabolismo , Cóclea/citologia , Cóclea/crescimento & desenvolvimento , Feminino , Potenciais Pós-Sinápticos Inibidores/fisiologia , Masculino , Ratos , Canais de Potássio Ativados por Cálcio de Condutância Baixa/metabolismo
14.
J Neurosci ; 38(16): 3939-3954, 2018 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-29572431

RESUMO

Gain control of the auditory system operates at multiple levels. Cholinergic medial olivocochlear (MOC) fibers originate in the brainstem and make synaptic contacts at the base of the outer hair cells (OHCs), the final targets of several feedback loops from the periphery and higher-processing centers. Efferent activation inhibits OHC active amplification within the mammalian cochlea, through the activation of a calcium-permeable α9α10 ionotropic cholinergic nicotinic receptor (nAChR), functionally coupled to calcium activated SK2 potassium channels. Correct operation of this feedback requires careful matching of acoustic input with the strength of cochlear inhibition (Galambos, 1956; Wiederhold and Kiang, 1970; Gifford and Guinan, 1987), which is driven by the rate of MOC activity and short-term facilitation at the MOC-OHC synapse (Ballestero et al., 2011; Katz and Elgoyhen, 2014). The present work shows (in mice of either sex) that a mutation in the α9α10 nAChR with increased duration of channel gating (Taranda et al., 2009) greatly elongates hair cell-evoked IPSCs and Ca2+ signals. Interestingly, MOC-OHC synapses of L9'T mice presented reduced quantum content and increased presynaptic facilitation. These phenotypic changes lead to enhanced and sustained synaptic responses and OHC hyperpolarization upon high-frequency stimulation of MOC terminals. At the cochlear physiology level these changes were matched by a longer time course of efferent MOC suppression. This indicates that the properties of the MOC-OHC synapse directly determine the efficacy of the MOC feedback to the cochlea being a main player in the "gain control" of the auditory periphery.SIGNIFICANCE STATEMENT Plasticity can involve reciprocal signaling across chemical synapses. An opportunity to study this phenomenon occurs in the mammalian cochlea whose sensitivity is regulated by efferent olivocochlear neurons. These release acetylcholine to inhibit sensory hair cells. A point mutation in the hair cell's acetylcholine receptor that leads to increased gating of the receptor greatly elongates IPSCs. Interestingly, efferent terminals from mutant mice present a reduced resting release probability. However, upon high-frequency stimulation transmitter release facilitates strongly to produce stronger and far longer-lasting inhibition of cochlear function. Thus, central neuronal feedback on cochlear hair cells provides an opportunity to define plasticity mechanisms in cholinergic synapses other than the highly studied neuromuscular junction.


Assuntos
Mutação com Ganho de Função , Células Ciliadas Auditivas/metabolismo , Plasticidade Neuronal , Receptores Nicotínicos/genética , Animais , Sinalização do Cálcio , Retroalimentação Fisiológica , Feminino , Células Ciliadas Auditivas/fisiologia , Potenciais Pós-Sinápticos Inibidores , Ativação do Canal Iônico , Masculino , Camundongos , Neurônios Eferentes/metabolismo , Neurônios Eferentes/fisiologia , Receptores Nicotínicos/metabolismo
15.
Proc Natl Acad Sci U S A ; 112(47): 14723-7, 2015 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-26553995

RESUMO

In the mammalian cochlea, acoustic information is carried to the brain by the predominant (95%) large-diameter, myelinated type I afferents, each of which is postsynaptic to a single inner hair cell. The remaining thin, unmyelinated type II afferents extend hundreds of microns along the cochlear duct to contact many outer hair cells. Despite this extensive arbor, type II afferents are weakly activated by outer hair cell transmitter release and are insensitive to sound. Intriguingly, type II afferents remain intact in damaged regions of the cochlea. Here, we show that type II afferents are activated when outer hair cells are damaged. This response depends on both ionotropic (P2X) and metabotropic (P2Y) purinergic receptors, binding ATP released from nearby supporting cells in response to hair cell damage. Selective activation of P2Y receptors increased type II afferent excitability by the closure of KCNQ-type potassium channels, a potential mechanism for the painful hypersensitivity (that we term "noxacusis" to distinguish from hyperacusis without pain) that can accompany hearing loss. Exposure to the KCNQ channel activator retigabine suppressed the type II fiber's response to hair cell damage. Type II afferents may be the cochlea's nociceptors, prompting avoidance of further damage to the irreparable inner ear.


Assuntos
Cóclea/inervação , Cóclea/patologia , Fibras Nervosas Amielínicas/patologia , Neurônios Aferentes/patologia , Trifosfato de Adenosina/farmacologia , Animais , Células Ciliadas Auditivas Externas/efeitos dos fármacos , Células Ciliadas Auditivas Externas/patologia , Ativação do Canal Iônico/efeitos dos fármacos , Íons , Canais de Potássio KCNQ/metabolismo , Fibras Nervosas Amielínicas/efeitos dos fármacos , Neurônios Aferentes/efeitos dos fármacos , Potássio/metabolismo , Ratos Sprague-Dawley , Receptores de Glutamato/metabolismo , Receptores Purinérgicos P2Y/metabolismo
16.
Adv Skin Wound Care ; 31(3): 109-117, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29438144

RESUMO

BACKGROUND: The long-term aesthetic appearance of scars is of great importance to patients. Biobrane (Smith and Nephew, Fort Worth, Texas), a biosynthetic skin dressing, is a successfully established dressing for the treatment of superficial wounds. A new silk barrier dressing (Dressilk; Prevor, Moulin de Verville, France) has also shown good results in wound healing. This study evaluated the long-term scar quality of superficial wounds treated with these dressings. METHODS: From February 2012 to May 2013, 11 patients with burns in need of skin grafting received donor site treatment. Study authors dressed 2 adjacent, standardized, partial-thickness skin graft donor sites on each participant with Biobrane or Dressilk. Scar formation on both treated areas was compared 24 months after initial application using subjective and objective assessment methods. RESULTS: Independent of treatment, the majority of the patients described scar quality similar to normal skin using subjective and objective evaluation tools. However, for scar perfusion, significantly lower oxygen saturation was shown in both treated areas compared with untreated skin. CONCLUSIONS: Comparatively, the 2 wound dressings showed similar results, making silk dressings an interesting alternative to biosynthetic ones.


Assuntos
Queimaduras/cirurgia , Cicatriz/prevenção & controle , Materiais Revestidos Biocompatíveis/uso terapêutico , Seda/uso terapêutico , Transplante de Pele/métodos , Adulto , Curativos Biológicos , Queimaduras/complicações , Cicatriz/etiologia , Estudos de Coortes , Estética , Feminino , Humanos , Escala de Gravidade do Ferimento , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Medição de Risco , Transplante de Pele/efeitos adversos , Resultado do Tratamento , Cicatrização/fisiologia
17.
Adv Skin Wound Care ; 31(7): 314-321, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29923901

RESUMO

OBJECTIVE: Because genital burns are rare, only limited information on treatment guidelines is available in the literature. Vital tissue should be preserved to promote spontaneous healing because reconstruction does not always lead to satisfying results. The aim of this report is to present a general overview of current, prevailing treatment for genital burns and compare this to study authors' experiences. In addition, the article describes an entirely new approach of tissue-preserving bromelain-based enzymatic debridement of genital burn wounds. METHODS: This single-center study includes all patients who were treated for severe genital and perineal burn wounds at a burn intensive care unit between December 1995 and December 2016. A review of literature was performed in PubMed covering the years 1990 to 2016. RESULTS: A total of 149 patients were admitted with severe burns or scalding of the genitals or the perineum. As in the majority of cases reported in the current literature, most of these patients were treated conservatively. When there was demarcation of necrotic tissue, tangential excision and skin grafting were performed, and since 2015, 3 patients admitted to this facility have been treated with bromelain-based debridement followed by spontaneous healing. Certain small-scale studies in the literature describe a disproportionate number of surgical interventions. CONCLUSIONS: Based on this evidence, study authors support a conservative view of genital burn treatment. Enzymatic debridement allows earlier and more selective debridement, which can improve the aesthetic outcome.


Assuntos
Queimaduras/terapia , Desbridamento/métodos , Genitália Feminina/lesões , Genitália Masculina/lesões , Períneo/lesões , Transplante de Pele/métodos , Bromelaínas/administração & dosagem , Queimaduras/cirurgia , Feminino , Humanos , Masculino , Cicatrização
18.
Adv Skin Wound Care ; 30(5): 223-229, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28426571

RESUMO

BACKGROUND: A fast and stable wound closure is important, especially for extended and unstable wounds found after burn injuries. Growth can regulate a variety of cellular processes, including those involved in wound healing. Growth differentiation factor 5 (GDF-5) can accelerate fibroblast cell migration, cell proliferation, and collagen synthesis, which are essential for wound healing. Nevertheless, no standardized evaluation of the effect of GDF-5 on the healing of full-thickness wounds has been published to date. METHODS: Five full-thickness skin defects were created on the backs of 6 minipigs. Three wounds were treated with GDF-5 in different concentrations with the help of a gelatin-collagen carrier, and 2 wounds served as control group. The first was treated with the gelatin carrier and an Opsite film (Smith & Nephew, Fort Worth, Texas), and the other was treated solely with an Opsite film that was placed above all wounds and renewed every second day. RESULTS: Growth differentiation factor 5 accelerates wound closure (10.91 [SD, 0.99] days) compared with treatment with the carrier alone (11.3 [SD, 1.49] days) and control wounds (13.3 [SD, 0.94] days). Epidermal cell count of wounds treated with GDF-5 revealed a higher number of cells compared with the control group. In addition, mean epidermal thickness was significantly increased in GDF-5-treated wounds compared with the control wounds. CONCLUSIONS: Because of its ability to improve skin quality, GDF-5 should be considered when developing composite biomaterials for wound healing.


Assuntos
Fator 5 de Diferenciação de Crescimento/uso terapêutico , Curativos Oclusivos , Cicatrização/efeitos dos fármacos , Ferimentos e Lesões/tratamento farmacológico , Administração Tópica , Animais , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Portadores de Fármacos/farmacologia , Gelatina/farmacologia , Distribuição Aleatória , Valores de Referência , Suínos , Porco Miniatura , Resistência à Tração/efeitos dos fármacos , Resultado do Tratamento , Cicatrização/fisiologia
19.
J Neurosci ; 35(26): 9701-6, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-26134652

RESUMO

Hearing loss among the elderly correlates with diminished social, mental, and physical health. Age-related cochlear cell death does occur, but growing anatomical evidence suggests that synaptic rearrangements on sensory hair cells also contribute to auditory functional decline. Here we present voltage-clamp recordings from inner hair cells of the C57BL/6J mouse model of age-related hearing loss, which reveal that cholinergic synaptic inputs re-emerge during aging. These efferents are functionally inhibitory, using the same ionic mechanisms as do efferent contacts present transiently before the developmental onset of hearing. The strength of efferent inhibition of inner hair cells increases with hearing threshold elevation. These data indicate that the aged cochlea regains features of the developing cochlea and that efferent inhibition of the primary receptors of the auditory system re-emerges with hearing impairment. SIGNIFICANCE STATEMENT: Synaptic changes in the auditory periphery are increasingly recognized as important factors in hearing loss. To date, anatomical work has described the loss of afferent contacts from cochlear hair cells. However, relatively little is known about the efferent innervation of the cochlea during hearing loss. We performed intracellular recordings from mouse inner hair cells across the lifespan and show that efferent innervation of inner hair cells arises in parallel with the loss of afferent contacts and elevated hearing threshold during aging. These efferent neurons inhibit inner hair cells, raising the possibility that they play a role in the progression of age-related hearing loss.


Assuntos
Cóclea/patologia , Células Ciliadas Auditivas Internas/fisiologia , Perda Auditiva/patologia , Inibição Neural/fisiologia , Acetilcolina/farmacologia , Fatores Etários , Oxirredutases do Álcool , Animais , Animais Recém-Nascidos , Apamina/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Proteínas Correpressoras , Conotoxinas/farmacologia , Curare/farmacologia , Proteínas de Ligação a DNA/metabolismo , Modelos Animais de Doenças , Potenciais Evocados Auditivos do Tronco Encefálico/efeitos dos fármacos , Potenciais Evocados Auditivos do Tronco Encefálico/fisiologia , Feminino , Glicinérgicos/farmacologia , Perda Auditiva/fisiopatologia , Camundongos , Camundongos Endogâmicos C57BL , Fármacos Neuromusculares não Despolarizantes/farmacologia , Fosfoproteínas/metabolismo , Estricnina/farmacologia
20.
J Neurosci ; 35(5): 1821-30, 2015 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-25653344

RESUMO

Cholinergic neurons of the brainstem olivary complex project to and inhibit outer hair cells (OHCs), refining acoustic sensitivity of the mammalian cochlea. In all vertebrate hair cells studied to date, cholinergic inhibition results from the combined action of ionotropic acetylcholine receptors and associated calcium-activated potassium channels. Although inhibition was thought to involve exclusively small conductance (SK potassium channels), recent findings have shown that BK channels also contribute to inhibition in basal, high-frequency OHCs after the onset of hearing. Here we show that the waveform of randomly timed IPSCs (evoked by high extracellular potassium) in high-frequency OHCs is altered by blockade of either SK or BK channels, with BK channels supporting faster synaptic waveforms and SK channels supporting slower synaptic waveforms. Consistent with these findings, IPSCs recorded from high-frequency OHCs that express BK channels are briefer than IPSCs recorded from low-frequency (apical) OHCs that do not express BK channels and from immature high-frequency OHCs before the developmental onset of BK channel expression. Likewise, OHCs of BKα(-/-) mice lacking the pore-forming α-subunit of BK channels have longer IPSCs than do the OHCs of BKα(+/+) littermates. Furthermore, serial reconstruction of electron micrographs showed that postsynaptic cisterns of BKα(-/-) OHCs were smaller than those of BKα(+/+) OHCs, and immunofluorescent quantification showed that efferent presynaptic terminals of BKα(-/-) OHCs were smaller than those of BKα(+/+) OHCs. Together, these findings indicate that BK channels contribute to postsynaptic function, and influence the structural maturation of efferent-OHC synapses.


Assuntos
Células Ciliadas Auditivas Externas/metabolismo , Potenciais Pós-Sinápticos Inibidores , Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Baixa/metabolismo , Sinapses/metabolismo , Animais , Neurônios Colinérgicos/metabolismo , Neurônios Colinérgicos/fisiologia , Feminino , Células Ciliadas Auditivas Externas/fisiologia , Canais de Potássio Ativados por Cálcio de Condutância Alta/antagonistas & inibidores , Canais de Potássio Ativados por Cálcio de Condutância Alta/genética , Masculino , Camundongos , Neurônios Eferentes/metabolismo , Neurônios Eferentes/fisiologia , Bloqueadores dos Canais de Potássio/farmacologia , Ratos , Ratos Sprague-Dawley , Canais de Potássio Ativados por Cálcio de Condutância Baixa/antagonistas & inibidores , Canais de Potássio Ativados por Cálcio de Condutância Baixa/genética , Sinapses/fisiologia
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