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1.
Sci Rep ; 14(1): 9249, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38649393

RESUMO

Submarine groundwater discharge (SGD) supplies nutrients, carbon, metals, and radionuclide tracers to estuarine and coastal waters. One aspect of SGD that is poorly recognized is its direct effect on dissolved oxygen (DO) demand in receiving waters, denoted here as SGD-OD. Sulfate-mediated oxidation of organic matter in salty coastal aquifers produces numerous reduced byproducts including sulfide, ammonia, dissolved organic carbon and nitrogen, methane, and reduced metals. When these byproducts are introduced to estuarine and coastal systems by SGD and are oxidized, they may substantially reduce the DO concentration in receiving waters and impact organisms living there. We consider six estuarine and coastal sites where SGD derived fluxes of reduced byproducts are well documented. Using data from these sites we present a semiquantitative model to estimate the effect of these byproducts on DO in the receiving waters. Without continued aeration with atmospheric oxygen, the study sites would have experienced periodic hypoxic conditions due to SGD-OD. The presence of H2S supplied by SGD could also impact organisms. This process is likely prevalent in other systems worldwide.

2.
J Insect Sci ; 21(6)2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34723333

RESUMO

Apis dorsata F. (Hymenoptera: Apidae), the giant honey bee of southern Asia, is an important pollinator of crops and non-cultivated angiosperms, and a producer of honey and beeswax. Its populations are in decline in many areas. Colonies migrate seasonally between highland and lowland nesting sites, taking advantage of available food sources. In 2009, a stopover site was discovered in Thailand where numerous migrating colonies bivouacked near one another. Bivouacs used the site again in 2010. I went to the site in 2016 to test the hypothesis that bees use the site regularly as part of an annual migration. I witnessed many bivouacs, spanning almost precisely the same time period and occupying the same area as in 2010. Here I describe their migratory dances in preparation for departure and their subsequent flights as well as periodic mass flight and defensive behavior. Analysis of photographs indicated that the bivouacking bees aged slowly and may thus live long enough to be capable of intergenerational transmission of migratory route knowledge. I describe attributes of the stopover site, e.g., abundant food and water availability, its location along a major river, and other possible navigational cues. Although the site is the only one of its kind so far known to researchers, such stopover sites probably exist wherever giant honey bees undertake long seasonal migrations. I recommend searching for bivouacking sites, particularly along rivers, wherever giant honey bees migrate. Stopover sites are undoubtedly essential to the life history and health of migratory bee populations, and thus warrant conservation policies.


Assuntos
Migração Animal , Abelhas , Animais , Voo Animal , Mel , Tailândia
3.
Am Surg ; 87(8): 1352-1355, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33342290

RESUMO

There is an acknowledged need for higher-quality evidence to quantify the benefit of surgical procedures, yet not enough has been done to improve the evidence base. This lack of evidence can prevent fully informed decision-making, lead to unnecessary or even harmful treatment, and contribute to wasteful expenditures of scare health care resources. Barriers to evidence generation include not only the long-recognized technical difficulties and ethical challenges of conducting randomized surgical trials, but also legal challenges that limit incentives to conduct surgical research as well as market-based challenges that make it difficult for those funding surgical research to recoup investment costs. These legal and market dynamics differ substantially from those surrounding new drug or device development. Nevertheless, obstacles could be overcome and overall expenditures could be reduced if a share of federal health care agency budgets were reallocated to generating randomized trial data, standardizing outcome measures, and conducting observational studies analogous to those that have been facilitated for drugs via the Food and Drug Administration's Sentinel Initiative. Until better quality evidence is available, ethical principles require adequate disclosure of the limited evidence base supporting current surgical procedures.


Assuntos
Medicina Baseada em Evidências/economia , Gastos em Saúde , Procedimentos Cirúrgicos Operatórios/economia , Pesquisa Biomédica/ética , Pesquisa Biomédica/legislação & jurisprudência , Ética Médica , Medicina Baseada em Evidências/legislação & jurisprudência , Financiamento Governamental , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto/economia , Ensaios Clínicos Controlados Aleatórios como Assunto/legislação & jurisprudência , Estados Unidos
5.
Mov Disord Clin Pract ; 7(5): 521-530, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32626797

RESUMO

BACKGROUND: Literature on asleep deep brain stimulation (DBS) of the ventralis intermedius (Vim) nucleus in essential tremor is relatively sparse. Furthermore, controversy exists as to whether indirect ("consensus" or "atlas-based") targeting of the Vim requires physiologic adjustment for effective clinical outcomes in DBS surgery. OBJECTIVES: The objective of this study was to evaluate the clinical results of asleep Vim DBS using indirect coordinates and real-time interventional magnetic resonance imaging guidance. METHODS: Retrospective review of a prospectively collected database was performed to identify patients with essential tremor undergoing asleep Vim DBS using interventional magnetic resonance imaging guidance. Stereotactic and clinical outcomes were abstracted and analyzed using descriptive statistics. RESULTS: A total of 12 consecutive patients were identified, all of whom were available for 6-month clinical follow-up. Stereotactic (radial) error was 0.5 ± 0.2 mm on the left and 0.5 ± 0.3 mm on the right. Fahn-Tolosa-Marin tremor scores in the treated limb(s) decreased by 71.2% ± 31.0% (P = 0.0088), The Essential Tremor Rating Assessment Scale activities of daily living improved by 74.9% ± 23.7% (P < 0.0001), and The Essential Tremor Rating Assessment Scale performance improved by 64.3 ± 16.2% (P = 0.0004). Surgical complications were mild and generally transient. Stimulation-related side effects were similar to those reported in historical series of awake Vim DBS. CONCLUSIONS: Asleep Vim DBS using indirect targeting and interventional magnetic resonance imaging-guided placement is safe and effective, with 6-month clinical results similar to those achieved with awake placement. These data support the use of asleep surgery in essential tremor and represent a baseline for comparison with future studies using more advanced targeting techniques.

6.
Stereotact Funct Neurosurg ; 98(4): 220-240, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32403112

RESUMO

Direct targeting methods for stereotactic neurosurgery in the treatment of essential tremor have been the subject of active research over the past decade but have not yet been systematically reviewed. We present a clinically oriented topic review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses Group guidelines. Our focus is studies using advanced magnetic resonance imaging (MRI) techniques (ultrahigh-field structural MRI, diffusion-weighted imaging, diffusion-tensor tractography, and functional MRI) for patient specific, in vivo identification of the ventral intermediate nucleus and the dentato-rubro-thalamic tract.


Assuntos
Núcleos Cerebelares/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Tremor Essencial/diagnóstico por imagem , Núcleo Rubro/diagnóstico por imagem , Técnicas Estereotáxicas , Tálamo/diagnóstico por imagem , Núcleos Cerebelares/cirurgia , Estimulação Encefálica Profunda/métodos , Tremor Essencial/cirurgia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Vias Neurais/diagnóstico por imagem , Vias Neurais/cirurgia , Núcleo Rubro/cirurgia , Tálamo/cirurgia
7.
World Neurosurg ; 139: 158-162, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32283321

RESUMO

BACKGROUND: Hemophilia is generally considered a contraindication to deep brain stimulation (DBS) and other elective intracranial surgery because of the elevated risk of perioperative hemorrhage. Two prior case reports have suggested, however, that DBS may be safe in patients with hemophilia who undergo appropriate factor replacement. Here, we describe a third case of DBS surgery for medically refractory essential tremor (ET) in a patient with hemophilia A. CASE DESCRIPTION: A 68-year-old right-handed man with mild hemophilia A presented for a 10-year history of bilateral (right greater than left), medically refractory ET. The patient was considered an appropriate candidate for DBS by a multidisciplinary movement disorders conference, and hematology consultation was obtained. Baseline preoperative laboratory results showed a quantitative factor VIII (FVIII) level of 38%. Perioperative management consisted of daily intravenous bolus doses of recombinant FVIII from the morning of surgery to postoperative day 10. The patient underwent uncomplicated unilateral DBS placement in the left ventralis intermedius thalamus. Intra- and postoperative imaging showed no hemorrhage. His postoperative course was uncomplicated except for a single self-limited episode of hematuria requiring no intervention. CONCLUSIONS: DBS placement for ET may be safe in patients with coexisting hemophilia A if appropriate FVIII replacement is given, which may be delivered as bolus infusions rather than continuous infusion.


Assuntos
Coagulantes/uso terapêutico , Estimulação Encefálica Profunda , Tremor Essencial/terapia , Fator VIII/uso terapêutico , Hemofilia A/tratamento farmacológico , Procedimentos Neurocirúrgicos/métodos , Assistência Perioperatória/métodos , Idoso , Perda Sanguínea Cirúrgica/prevenção & controle , Tremor Essencial/complicações , Hemofilia A/complicações , Humanos , Infusões Intravenosas , Masculino , Hemorragia Pós-Operatória/prevenção & controle , Implantação de Prótese/métodos , Proteínas Recombinantes , Núcleos Ventrais do Tálamo/cirurgia
8.
Clin Neurol Neurosurg ; 194: 105819, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32259672

RESUMO

OBJECTIVE: Facial pain refractory to medical treatments may benefit from neurosurgical interventions. Only a few studies have reported on the efficacy of peripheral trigeminal stimulation and more specifically supraorbital nerve (SON) and infraorbital nerve (ION) stimulation for the treatment of facial pain. PATIENTS AND METHODS: In the present study, we identified all patients at our institution who underwent SON and/or ION stimulation for treatment of facial pain due to post-herpetic, traumatic or idiopathic etiology. Relevant pre and post-operative outcomes were analyzed. RESULTS: We identified 15 patients who underwent SON and/or ION stimulation. Among them, 12 (80 %) endorsed >50 % pain relief during the trial stimulation period. After a median follow-up of 5.8 months with permanent implantation, 1 patient (8.3 %) was diagnosed with lead erosion and IPG migration, two patients had lead infections (16.7 %) and one (8.3 %) had wound dehiscence. No lead migrations were identified during the long-term follow-up. The VAS score showed a statistically significant reduction from a median pre-operative score of 7 to a post-operative score of 1.8 (p = 0.011), which corresponded to a 74.3 % average pain reduction. CONCLUSION: SON and/or ION stimulation can be an effective treatment for intractable facial pain due to post-herpetic, traumatic or idiopathic etiology; however the complication rate is relatively high. Future prospective studies with longer follow-up periods are warranted.


Assuntos
Terapia por Estimulação Elétrica/métodos , Dor Facial/cirurgia , Dor Facial/terapia , Nervo Trigêmeo , Adulto , Idoso , Idoso de 80 Anos ou mais , Terapia por Estimulação Elétrica/efeitos adversos , Eletrodos Implantados/efeitos adversos , Traumatismos do Nervo Facial/complicações , Traumatismos do Nervo Facial/terapia , Feminino , Seguimentos , Migração de Corpo Estranho/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Neuralgia Pós-Herpética/terapia , Procedimentos Neurocirúrgicos/métodos , Medição da Dor , Dor Intratável , Nervos Periféricos , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Resultado do Tratamento
9.
Neuromodulation ; 23(6): 796-804, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32141164

RESUMO

BACKGROUND: Peripheral neurostimulation (PNS) for medically refractory trigeminal pain is an emerging alternative to traditional surgical approaches, with safety and efficacy demonstrated in several retrospective series and a prospective trial currently in progress. Many existing studies suffer from relatively small numbers and short or inconsistent follow-up, making balanced treatment assessment difficult. MATERIALS AND METHODS: Consecutive cases of trial and permanent placement of trigeminal branch stimulation electrodes by a single surgeon from May 2014 through January 2019 were retrospectively reviewed from a prospectively collected database, following the PROCESS guidelines for surgical case series. Outcomes were assessed at six months and at last follow-up. RESULTS: Ninteen patients underwent trial electrode placement, with 15 patients undergoing permanent system placement. The most common diagnoses were idiopathic trigeminal neuralgia Type 2 (N = 8) and trigeminal neuropathic pain (N = 7). Median follow-up was 14 months (range 6-58 months). At last follow-up, 12 of 15 implanted patients (80%) were still receiving stimulation, with mean (median) pain reduction of 52.3% (47.5%). Infection and revision rates were high, although erosion and migration, which have typically plagued trigeminal PNS surgery, did not occur. Implanted systems were well-tolerated, with excellent cosmetic outcomes and high patient satisfaction that proved durable over long follow-up. CONCLUSIONS: We present a single-institution series of PNS for complex craniofacial pain involving the trigeminal nerve. The procedure is safe, effective and durable over at least one year in the large majority of a well-selected patient population.


Assuntos
Terapia por Estimulação Elétrica , Neuralgia/terapia , Nervo Trigêmeo , Terapia por Estimulação Elétrica/efeitos adversos , Eletrodos Implantados , Seguimentos , Humanos , Estudos Prospectivos , Estudos Retrospectivos , Resultado do Tratamento
10.
J Neural Eng ; 17(1): 016074, 2020 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-31978914

RESUMO

OBJECTIVE: New innovations in deep brain stimulation (DBS) enable directional current steering-allowing more precise electrical stimulation of the targeted brain structures for Parkinson's disease, essential tremor and other neurological disorders. While intra-operative navigation through MRI or CT approaches millimeter accuracy for placing the DBS leads, no existing modality provides feedback of the currents as they spread from the contacts through the brain tissue. In this study, we investigate transcranial acoustoelectric imaging (tAEI) as a new modality to non-invasively image and characterize current produced from a directional DBS lead. tAEI uses ultrasound (US) to modulate tissue resistivity to generate detectable voltage signals proportional to the local currents. APPROACH: An 8-channel directional DBS lead (Infinity 6172ANS, Abbott Inc) was inserted inside three adult human skulls submerged in 0.9% NaCl. A 2.5 MHz linear array delivered US pulses through the transtemporal window and focused near the contacts on the lead, while a custom amplifier and acquisition system recorded the acoustoelectric (AE) interaction used to generate images. MAIN RESULTS: tAEI detected monopolar current with stimulation pulses as short as 100 µs with an SNR ranging from 10-27 dB when using safe US pressure (mechanical indices <0.78) and injected current of ~2 mA peak amplitude. Adjacent contacts were discernable along the length and within each ring of the lead with a mean radial separation between contacts of 2.10 and 1.34 mm, respectively. SIGNIFICANCE: These results demonstrate the feasibility of tAEI for high resolution mapping of directional DBS currents using clinically-relevant stimulation parameters. This new modality may improve the accuracy for placing the DBS leads, guide calibration and programming, and monitor long-term performance of DBS for treatment of Parkinson's disease.


Assuntos
Estimulação Encefálica Profunda/métodos , Neuroestimuladores Implantáveis , Lobo Parietal/patologia , Som , Estimulação Transcraniana por Corrente Contínua/métodos , Adulto , Cadáver , Estimulação Encefálica Profunda/instrumentação , Humanos , Estimulação Transcraniana por Corrente Contínua/instrumentação
11.
World Neurosurg ; 128: 422-425, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31108251

RESUMO

BACKGROUND: Malignant melanotic schwannian tumors (MMSTs) are rare peripheral nerve sheath tumors that typically exhibit benign clinical presentation and histopathology but malignant long-term behavior. CASE DESCRIPTION: We report a case of a 22-year-old male with a T9-11 MMST who presented with acute paraplegia and complete loss of sacral function. Despite emergent decompression, he did not recover motor, sensory or bladder function, although bowel function did normalize. CONCLUSIONS: The anatomic location and rapid presentation of permanent deficits are suggestive of infarction of the spinal cord supplied by the artery of Adamkiewicz, a rare presentation of this disorder and of spinal schwannomas in general.


Assuntos
Infarto/etiologia , Neurofibrossarcoma/complicações , Paraplegia/etiologia , Isquemia do Cordão Espinal/etiologia , Neoplasias da Medula Espinal/complicações , Descompressão Cirúrgica , Humanos , Infarto/diagnóstico por imagem , Infarto/patologia , Masculino , Neurofibrossarcoma/diagnóstico por imagem , Neurofibrossarcoma/patologia , Neurofibrossarcoma/cirurgia , Distúrbios Somatossensoriais/etiologia , Isquemia do Cordão Espinal/diagnóstico por imagem , Isquemia do Cordão Espinal/patologia , Neoplasias da Medula Espinal/diagnóstico por imagem , Neoplasias da Medula Espinal/patologia , Neoplasias da Medula Espinal/cirurgia , Adulto Jovem
12.
Reprod Biol Endocrinol ; 17(1): 29, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30841911

RESUMO

BACKGROUND: Proteomic studies of follicular fluid (FF) exist for several species, including the horse; however, the seasonal influence on FF proteome has not been explored in livestock. The application of high-throughput proteomics of FF in horse has the potential to identify seasonal variations of proteins involved in follicle and oocyte growth. METHODS: This study (i) profiles the proteomes of equine FF collected from dominant growing follicles during the spring anovulatory season (SAN), and spring (SOV), summer (SUM), and fall (FOV) ovulatory seasons; and (ii) identifies season-dependent regulatory networks and associated key proteins. RESULTS: Regardless of season, a total of 90 proteins were identified in FF, corresponding to 63, 72, 69, and 78 proteins detected in the SAN, SOV, SUM, and FOV seasons, respectively. Fifty-two proteins were common to all seasons, a total of 13 were unique to either season, and 25 were shared between two seasons or more. Protein-to-protein interaction (PPI) analysis indicated the likely critical roles of plasminogen in the SAN season, the prothrombin/plasminogen combination in SUM, and plasminogen/complement C3 in both SOV and FOV seasons. The apolipoprotein A1 appeared crucial in all seasons. The present findings show that FF proteome of SUM differs from other seasons, with FF having high fluidity (low viscosity). CONCLUSIONS: The balance between the FF contents in prothrombin, plasminogen, and coagulation factor XII proteins favoring FF fluidity may be crucial at the peak of the ovulatory season (SUM) and may explain the reported lower incidence of hemorrhagic anovulatory follicles during the SUM season.


Assuntos
Líquido Folicular/metabolismo , Cavalos/metabolismo , Proteínas/metabolismo , Animais , Feminino , Proteínas/química , Proteínas/isolamento & purificação , Proteômica , Reprodução , Estações do Ano
13.
Neuroimage ; 194: 272-282, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-30894331

RESUMO

The thalamus and its nuclei are largely indistinguishable on standard T1 or T2 weighted MRI. While diffusion tensor imaging based methods have been proposed to segment the thalamic nuclei based on the angular orientation of the principal diffusion tensor, these are based on echo planar imaging which is inherently limited in spatial resolution and suffers from distortion. We present a multi-atlas segmentation technique based on white-matter-nulled MP-RAGE imaging that segments the thalamus into 12 nuclei with computation times on the order of 10 min on a desktop PC; we call this method THOMAS (THalamus Optimized Multi Atlas Segmentation). THOMAS was rigorously evaluated on 7T MRI data acquired from healthy volunteers and patients with multiple sclerosis by comparing against manual segmentations delineated by a neuroradiologist, guided by the Morel atlas. Segmentation accuracy was very high, with uniformly high Dice indices: at least 0.85 for large nuclei like the pulvinar and mediodorsal nuclei and at least 0.7 even for small structures such as the habenular, centromedian, and lateral and medial geniculate nuclei. Volume similarity indices ranged from 0.82 for the smaller nuclei to 0.97 for the larger nuclei. Volumetry revealed that the volumes of the right anteroventral, right ventral posterior lateral, and both right and left pulvinar nuclei were significantly lower in MS patients compared to controls, after adjusting for age, sex and intracranial volume. Lastly, we evaluated the potential of this method for targeting the Vim nucleus for deep brain surgery and focused ultrasound thalamotomy by overlaying the Vim nucleus segmented from pre-operative data on post-operative data. The locations of the ablated region and active DBS contact corresponded well with the segmented Vim nucleus. Our fast, direct structural MRI based segmentation method opens the door for MRI guided intra-operative procedures like thalamotomy and asleep DBS electrode placement as well as for accurate quantification of thalamic nuclear volumes to follow progression of neurological disorders.


Assuntos
Mapeamento Encefálico/métodos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Núcleos Talâmicos/anatomia & histologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
14.
Stereotact Funct Neurosurg ; 97(5-6): 285-292, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31968343

RESUMO

BACKGROUND: Peripheral neurostimulation (PNS) for medically refractory trigeminal and craniofacial pain is an emerging alternative to traditional surgical approaches. Technical problems with craniofacial PNS have included electrode migration and erosion, limiting the utility and cost-effectiveness of this procedure. OBJECTIVE: To review our institutional surgical technique for trigeminal PNS implantation, focusing on a novel technique for electrode anchoring. METHODS: Consecutive cases of permanent craniofacial PNS placement by a single surgeon over 36 months were reviewed for surgical technique and technical outcomes. Electrodes were placed percutaneously with open anchoring to the pericranium at a separate parietal incision. RESULTS: Sixteen systems (53 electrodes) were implanted in 14 patients. Median follow-up was 13 months (range, 5-29 months). Electrode placement was successful in all cases with no intraoperative complications. There was 1 lead migration (6.3% per patient; 1.8% per lead) and no cases of erosion. Two patients (14.3%) required explant for infection, 1 of whom was successfully reimplanted. Three patients (21.4%) underwent surgical revision other than for infection. CONCLUSIONS: We present an improved method for craniofacial PNS surgery which introduces a separate incision for electrode anchoring at the parietal boss. This technique simplifies the procedure and greatly reduces rates of erosion and migration, improving patient comfort and satisfaction.


Assuntos
Terapia por Estimulação Elétrica/métodos , Eletrodos Implantados , Dor Facial/diagnóstico por imagem , Dor Facial/terapia , Nervo Trigêmeo/diagnóstico por imagem , Adulto , Terapia por Estimulação Elétrica/instrumentação , Dor Facial/fisiopatologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Nervo Trigêmeo/fisiopatologia
15.
Theriogenology ; 126: 88-94, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30543999

RESUMO

Preservation of cellular integrity and its mechanisms after ovarian tissue cryopreservation (OTC) and in vitro culture (IVC) procedures are crucial aspects for the success of preservation and recovery of female fertility. This study aimed to evaluate the effects of two cryopreservation methods (slow-freezing, SF, and vitrification, VIT) on the equine ovarian tissue after 1, 3, and 7 days of IVC by assessing: (i) preantral follicle morphology and distribution of follicle classes; (ii) protein expression of markers of cell proliferation for EGFR and Ki-67; (iii) markers of apoptosis for Bax and Bcl-2; and (iv) DNA fragmentation. Percentages of normal primordial follicles were similar (P > 0.05) among SF-control, VIT-control, and fresh control groups. After 7 days of culture, VIT-IVC7 had a greater (P < 0.05) total percentage of normal preantral follicles when compared with SF-IVC7, but both had a lower (P < 0.05) percentage than fresh IVC7 group. Prior to and after 7 days of culture, expression of EGFR and Ki-67 were similar (P > 0.05) among fresh, SF, and VIT groups. After 7 days of culture, VIT had higher (P < 0.05) Bax expression than the fresh and SF tissues, but Bcl-2 was similar (P > 0.05) among groups. Prior to IVC, TUNEL signals were similar (P > 0.05) among groups; however, VIT-IVC7 had greater (P < 0.05) TUNEL signals when compared with the fresh IVC7 group. In conclusion, findings demonstrated: (i) similar efficiency between SF and VIT compared with fresh control to preserve morphologically normal follicles; and (ii) similar tissue functionality and cell proliferation capability after equine OTC by either SF and VIT methods following IVC for 7 days. The results herein presented shed light on equine fertility preservation programs using OTC techniques.


Assuntos
Criopreservação/veterinária , Cavalos/fisiologia , Ovário/citologia , Preservação de Tecido/veterinária , Animais , Apoptose , Proliferação de Células , Criopreservação/métodos , Fragmentação do DNA , Feminino , Preservação da Fertilidade/métodos , Preservação da Fertilidade/veterinária , Estresse Fisiológico , Preservação de Tecido/métodos , Vitrificação
16.
Ultrasound Med Biol ; 44(11): 2345-2357, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30119863

RESUMO

We describe a new application of acoustoelectric imaging for non-invasive mapping of the location, magnitude and polarity of current generated by a clinical deep brain stimulation (DBS) device. Ultrasound at 1MHz was focused near the DBS device as short current pulses were injected across different DBS leads. A recording electrode detected the high-frequency acoustoelectric interaction signal. Linear scans of the US beam produced time-varying images of the magnitude and polarity of the induced current, enabling precise localization of the DBS leads within 0.70mm, a detection threshold of 1.75mA at 1 MPa and a sensitivity of 0.52 ± 0.07 µV/(mA*MPa). Monopole and dipole configurations in saline were repeated through a human skullcap. Despite 13.8-dB ultrasound attenuation through bone, acoustoelectric imaging was still >10dB above background with a sensitivity of 0.56 ± 0.10 µV/(mA*MPa). This proof-of-concept study indicates that selective mapping of lead currents through a DBS device may be possible using non-invasive acoustoelectric imaging.


Assuntos
Estimulação Encefálica Profunda/métodos , Crânio/diagnóstico por imagem , Terapia por Ultrassom/métodos , Humanos
17.
Water Res ; 144: 603-615, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30096687

RESUMO

The shores of the Pearl River estuary are home to 35 million people. Their wastes are discharged into the large river delta-front estuary (LDE), one of the most highly polluted systems in the world. Here we construct a radium reactive transport model to estimate the terrestrial groundwater discharge (TGD) into the highly urbanized Pearl River LDE. We find the TGD comprises only approximately 0.9% in term of water discharge compared to the river discharge. The TGD in the Pearl River LDE delivers significant chemical fluxes to the coast, which are comparable to the fluvial loadings from Pearl River and other world major rivers. Of particular importance is the flux of ammonium because of its considerable role in Pearl River estuary eutrophication and hypoxia. Unlike the ammonium in many other aquifers, the ammonium in the Pearl River aquifer system is natural and originated from organic matter remineralization by sulfate reduction in the extremely reducing environment. The TGD derived NH4+ is as much as 5% of the upstream Pearl River fluvial loading and 42% of the anthropogenic inputs. This high groundwater NH4+ flux may greatly intensify the eutrophication, shift the trophic states, and lead to alarming hypoxia within the affected ecosystems in the Pearl River LDE. The large TGD derived chemical fluxes will lead to deterioration of water and will potentially affect human health.


Assuntos
Estuários , Água Subterrânea/química , Rádio (Elemento)/análise , Compostos de Amônio/análise , China , Ecossistema , Monitoramento Ambiental , Eutrofização , Isótopos/análise , Rios/química , Urbanização
18.
Brain Connect ; 8(6): 343-349, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29877094

RESUMO

Many nonmotor symptoms (e.g., hyposmia) appear years before the cardinal motor features of Parkinson's disease (PD). It is thus desirable to be able to use noninvasive brain imaging methods, such as magnetic resonance imaging (MRI), to detect brain abnormalities in early PD stages. Among the MRI modalities, diffusion-tensor imaging (DTI) is suitable for detecting changes in brain tissue structure due to neurological diseases. The main purpose of this study was to investigate whether DTI signals measured from brain regions involved in early stages of PD differ from those of healthy controls. To answer this question, we analyzed whole-brain DTI data of 30 early-stage PD patients and 30 controls using improved region of interest-based analysis methods. Results showed that (i) the fractional anisotropy (FA) values in the olfactory tract (connected with the olfactory bulb: one of the first structures affected by PD) are lower in PD patients than healthy controls; (ii) FA values are higher in PD patients than healthy controls in the following brain regions: corticospinal tract, cingulum (near hippocampus), and superior longitudinal fasciculus (temporal part). Experimental results suggest that the tissue property, measured by FA, in olfactory regions is structurally modulated by PD with a mechanism that is different from other brain regions.


Assuntos
Mapeamento Encefálico , Encéfalo/diagnóstico por imagem , Doença de Parkinson/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anisotropia , Imagem de Tensor de Difusão , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/diagnóstico por imagem
19.
Sci Adv ; 4(1): eaao1302, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29326980

RESUMO

Rising temperatures in the Arctic Ocean region are responsible for changes such as reduced ice cover, permafrost thawing, and increased river discharge, which, together, alter nutrient and carbon cycles over the vast Arctic continental shelf. We show that the concentration of radium-228, sourced to seawater through sediment-water exchange processes, has increased substantially in surface waters of the central Arctic Ocean over the past decade. A mass balance model for 228Ra suggests that this increase is due to an intensification of shelf-derived material inputs to the central basin, a source that would also carry elevated concentrations of dissolved organic carbon and nutrients. Therefore, we suggest that significant changes in the nutrient, carbon, and trace metal balances of the Arctic Ocean are underway, with the potential to affect biological productivity and species assemblages in Arctic surface waters.

20.
Theriogenology ; 84(4): 600-7, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26025241

RESUMO

Declines of the southern Rocky Mountain population of boreal toad (Anaxyrus boreas boreas) have led to the establishment of a captive assurance population and reintroduction program, in an attempt to preserve and propagate this geographically isolated population. One of the unique adaptations of this species is its ability to survive in cold environments by undergoing long periods of hibernation. In captivity, hibernation can be avoided altogether, decreasing morbidity caused by compromised immune systems. However, it is not entirely clear how essential hibernation is to reproductive success. In this study, the effects of hibernation versus nonhibernation, and exogenous hormones on oviposition, were examined in boreal toad females in the absence of males. In the summers of 2011 and 2012, 20 females housed at Mississippi State University were treated with a double priming dose of hCG and various ovulatory doses of hCG and LH-releasing hormone analog but denied hibernation. Exogenous hormones, in the absence of hibernation, could not induce oviposition over two breeding seasons (2011-2012). In contrast, during the summer of 2012 and 2013, 17 of 22 females (77%) housed at the Native Aquatic Species Restoration Facility (Alamosa, CO, USA) oviposited after they were treated with two priming doses of hCG (3.7 IU/g each) and a single ovulation dose of hCG (13.5 IU/g) and LH-releasing hormone analog (0.4 µg/g) after hibernation. There was a significant difference in oviposition between females that were hibernated and received hormones (2012, P < 0.05 and 2013, P < 0.01) compared to hibernated control females. In 2013, 12 of 16 remaining Mississippi State University females from the same group used in 2011 and 2012 were hibernated for 1, 3, and 6 months, respectively and then treated with the same hormone regimen administered to females at the Native Aquatic Species Restoration Facility. Together, hibernation and hormone treatments significantly increased oviposition (P < 0.05), with 33% of females ovipositing. These results suggest that (1) hibernation is a key factor influencing oviposition that cannot be exclusively circumvented by exogenous hormones; (2) females do not require the presence of a male to oviposit after hormone treatments; and (3) longer hibernation periods are not beneficial for oviposition. The hormonal induction of oviposition in the absence of males and shorter hibernation periods could have important captive management implications for the boreal toad. Furthermore, the production of viable offspring by IVF where natural mating is limited could become an important tool for genetic management of this boreal toad captive population.


Assuntos
Bufonidae/fisiologia , Gonadotropina Coriônica/farmacologia , Hormônio Liberador de Gonadotropina/farmacologia , Hibernação/fisiologia , Oviposição/efeitos dos fármacos , Animais , Feminino , Oviposição/fisiologia , Fatores de Tempo
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