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1.
Arch Gynecol Obstet ; 292(6): 1361-6, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26112357

RESUMO

OBJECTIVE: "Every colposcopic criterion must be mirrored by histopathology". We investigated the histomorphologic equivalent of four colposcopic criteria, which are associated with CIN 2 and/or CIN 3 and therefore called pathognomonic. PATIENTS AND METHODS: We diagnosed inner border sign, ridge sign, rag sign and/or cuffed gland openings using VITOM(®) videocolposcopy in 255 patients which are consistent with major change. Histopathologic examination included immunohistochemical staining for p16, Ki 67 and stathmin-1 and micro-photographic documentation. RESULTS: The histopathologic pattern specific for each of the four pathognomonic colposcopic criteria was reproducibly identified: inner border sign showed a sharp demarcation between low- and high-grade CIN, in ridge sign high-grade CIN adjoined directly the squamocolumnar junction, in rag sign, high-grade CIN was detached from stroma, and in cuffed gland openings, the entrance to a gland was rimmed by CIN, respectively. In 255 patients, the leading pathognomonic sign was inner border in 12.1 %, ridge in 34.1 %, rag in 18 %, and cuffed glands in 35.7 %, respectively. Inner border sign, ridge sign, rag sign and/or cuffed gland openings were associated with CIN 2 or 3 in 97, 98, 98 and 98 %, respectively. In 153 out of 255 patients, we found a combination of pathognomonic signs with ridge sign being the most frequent combined criterion (in 21 % of patients as second pathognomonic sign). CONCLUSION: The morphology of the four pathognomonic colposcopic criteria, inner border sign, ridge sign, rag sign and cuffed crypt openings, is reproduced in histopathology. These criteria are highly associated with CIN 2 or CIN 3.


Assuntos
Colposcopia/métodos , Displasia do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/diagnóstico , Adulto , Idoso , Carcinoma de Células Escamosas/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Fotografação , Exame Físico , Valor Preditivo dos Testes , Gravidez , Reprodutibilidade dos Testes
2.
Geburtshilfe Frauenheilkd ; 75(10): 1063-1068, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28435170

RESUMO

Introduction: To evaluate, if targeted strip biopsies decrease trauma/pain perception while maintaining diagnostic accuracy in patients with the diagnosis of high-grade squamous intraepithelial lesions of the uterine cervix. Patients and Methods: Between July 1st and December 31st 2014 we performed colposcopically directed strip biopsies in 102 patients with colposcopic suspicion of high-grade squamous intraepithelial lesions of the uterine cervix. We used a 3 mm curette for harvesting tissue samples under VITOM® videocolposcopy. So far, 60 patients underwent additional loop excision. Histologic examination of strip biopsies and loop specimens included routine hematoxylin and eosin staining as well as immunohistochemical staining for p16, Ki 67 and stathmin-1. Results: 55 patients (53 %), were histologically diagnosed with cervical intraepithelial neoplasia grade 3 on strip biopsies. Adenocarcinoma in situ was diagnosed in 2 patients (2 %), cervical intraepithelial neoplasia grade 2 in 35 patients (34 %), and cervical intraepithelial neoplasia grade 1 in 10 patients (10 %). The agreement between histologic results of strip biopsy and loop specimen was highly significant: In all 60 strip biopsies diagnosed with high-grade squamous intraepithelial lesions this diagnosis was confirmed histologically during follow-up loop specimen excision (high-grade squamous intraepithelial lesions in 58 patients, invasive disease in 2 patients). The pain level experienced during strip biopsy was rated on average 0.25 on a scale from 0 to 10. No clinically significant bleeding was reported. Conclusion: Targeted strip biopsies with a 3 mm curette are a reliable procedure to diagnose high-grade squamous intraepithelial lesions of the uterine cervix and yield high patient satisfaction (Video 1).

3.
Geburtshilfe Frauenheilkd ; 72(10): 945-948, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25258454

RESUMO

Background: Aim of the study was to compare the quality of loop excision using a colposcope with results using the VITOM system. Results compared included cervical volume removed, intra- and postoperative complications, and positive resection margins. Methods: A total of 200 patients with histologically confirmed high-grade cervical premalignant lesions, persistent atypical cytological results and/or suspicious colposcopic findings, and cytological and histological discrepancies were included in the study. In transformation zone type 1 (T1) only a superficial cone biopsy was done, in zones type 2 and 3 (T2 and T3) a superficial outside cone biopsy or a deeper inside cone biopsy were done respectively, followed by endocervical curettage. Volume of removed tissue, complications, and positive resection margins were compared for the colposcopy and the VITOM groups. Findings: Demographic and reproductive features were similar between groups. In the VITOM group 49 % of patients had zone T1, 30 % had zone T2, and 21 % had zone T3. In the group of patients managed by colposcopy, 48, 45, and 7 % of patients had zone T1, T2 and T3 zone, respectively (p < 0.01). A "top hat" procedure was done in 65 % of patients in the VITOM group and in 38 % of patients in the colposcopy group (p < 0.05). Mean volume of removed cervical tissue measured was similar, with 1.2 cm3 measured in the VITOM group and 1.14 cm3 in the colposcopy group (p > 0.05). There were no significant differences in the type of procedure or the mean volume of removed tissue. Results were similar for both groups with respect to positive resection margins and complications. Conclusion: VITOM is a safe and reliable system. Results using the VITOM system are comparable to those obtained with conventional colposcopy. The potential advantage of VITOM is the broader availability of endoscopic systems in the operating theatre.

4.
Int J Clin Pharmacol Ther ; 49(7): 451-60, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21726496

RESUMO

OBJECTIVE: To investigate whether a pharmacokinetic drug-drug interaction exists between theophylline (THEO), a CYP1A2 substrate with a narrow therapeutic index, and the concomitant substrate roflumilast (ROF), a novel selective PDE4 inhibitor partially metabolized by CYP1A2. MATERIALS AND METHODS: In an open-label, 2-period, crossover study, Treatment A (oral ROF 500 µg q.d. on Days 6 - 10 in addition to oral THEO 375 mg b.i.d. on Days 1 - 10) and treatment B (oral ROF 500 µg q.d. on Days 1 - 5) were administered consecutively in random order to each of 24 healthy adult subjects. Both periods were separated by a wash-out phase of at least 10 days. Plasma samples for pharmacokinetic evaluation (AUC, Cmax, t1/2, tmax) including percent peak-trough fluctuation (%PTF) of THEO were taken. Point estimates and the 90% confidence interval of the geometric mean ratios were calculated for AUC and Cmax and descriptive statistics for other pharmacokinetic parameters. RESULTS: Concomitant administration of ROF did not alter pharmacokinetics of THEO. With coadministered THEO, only steady-state total exposure to ROF (AUC) was increased by 28% whereas other pharmacokinetic parameters (t1/2, Cmax, tmax) of ROF and of the active metabolite roflumilast-N-oxide (R-NO), its main contributor to the pharmacodynamic effects, remained unchanged. CONCLUSIONS: Neither ROF nor its main metabolite had any impact on the metabolism of the concomitant CYP1A2 substrate THEO in humans. Though co-administration of THEO resulted in a minor increase (28%) in total ROF exposure, no safety or tolerability concerns and no altered total PDE4 inhibition of both ROF and R-NO, were observed.


Assuntos
Aminopiridinas/farmacocinética , Benzamidas/farmacocinética , Broncodilatadores/farmacocinética , Inibidores da Fosfodiesterase 4/farmacocinética , Teofilina/farmacocinética , Adolescente , Adulto , Área Sob a Curva , Pressão Sanguínea/efeitos dos fármacos , Temperatura Corporal/efeitos dos fármacos , Broncodilatadores/efeitos adversos , Estudos Cross-Over , Ciclopropanos/farmacocinética , Citocromo P-450 CYP1A2/metabolismo , Interações Medicamentosas , Feminino , Meia-Vida , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Controle de Qualidade , Teofilina/efeitos adversos , Equivalência Terapêutica , Adulto Jovem
5.
Gynecol Oncol ; 95(2): 336-40, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15491754

RESUMO

OBJECTIVES: Paget disease of the vulva is a rare lesion that accounts for <1% of vulva neoplasms. A 12% prevalence of invasive Paget carcinoma and a 4% prevalence of associated adenocarcinomas are described. Furthermore, a high recurrence rate of 30% after surgical therapy is observed. This study aims to search for therapeutic strategies for recurrent Paget disease, which are less mutilating and less aggressive than reexcision, x-ray therapy, or chemotherapy. Trastuzumab (Herceptin) is a recombinant monoclonal antibody against HER-2/neu, approved by the U.S. FDA for the treatment of patients with HER-2/neu-positive metastatic breast carcinomas. The results of recent studies indicate that HER-2/neu oncoprotein may play a role in the pathogenesis of extramammary Paget disease. METHODS: Using HercepTest, we analyzed HER-2/neu overexpression in seven noninvasive Paget lesions, two invasive lesions, and one Paget disease of the vulva with underlying adenocarcinoma. In addition, we investigated five mammary Paget diseases. RESULTS: Overexpression of HER-2/neu oncoprotein labeling exclusively the membranes of Paget cells was demonstrated in 8 out of 10 cases. One noninvasive and one with underlying adenocarcinoma stained negatively. Overexpression of HER-2/neu was demonstrated in all five cases of mammary Paget disease. CONCLUSION: Using HercepTest as a standardized detection system, overexpression of HER-2/neu can be demonstrated in a majority of both noninvasive and invasive Paget disease of the vulva. The use of Trastuzumab should be considered for the treatment of patients with recurrent Paget disease of the vulva with overexpression of HER-2/neu.


Assuntos
Doença de Paget Extramamária/metabolismo , Doença de Paget Mamária/metabolismo , Receptor ErbB-2/biossíntese , Neoplasias Vulvares/metabolismo , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Carcinoma in Situ/metabolismo , Carcinoma in Situ/patologia , Carcinoma Ductal/metabolismo , Carcinoma Ductal/patologia , Feminino , Humanos , Doença de Paget Extramamária/patologia , Doença de Paget Mamária/patologia , Inclusão em Parafina , Neoplasias Vulvares/patologia
7.
Eur Radiol ; 11(12): 2516-20, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11734951

RESUMO

Langerhans' cell histiocytosis (LCH) is a disorder of histiocytic proliferation that primarily affects infants. Imaging findings of a rare case of lung and liver involvement in an adult are presented. High-resolution computed tomography (HRCT) of the lungs showed confluent thin-walled cystic air spaces compatible with advanced LCH. Liver CT and MRI revealed unspecific signs of fatty infiltration. Irregular widening of peripheral bile ducts was displayed in breath-hold MR cholangiography. This pattern is considered characteristic for sclerosing cholangitis and should support the diagnosis of LCH in case of concomitant cystic pulmonary disease, even in adult patients.


Assuntos
Colangiografia , Colangite Esclerosante/diagnóstico , Histiocitose de Células de Langerhans/diagnóstico , Hepatopatias/diagnóstico , Pneumopatias/diagnóstico , Imageamento por Ressonância Magnética , Tomografia Computadorizada por Raios X , Idoso , Ductos Biliares/patologia , Meios de Contraste , Gadolínio DTPA , Humanos , Fígado/patologia , Pulmão/patologia , Masculino
8.
Gynecol Oncol ; 75(3): 427-31, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10600301

RESUMO

OBJECTIVE: Women infected with the human immunodeficiency virus (HIV) have an increased risk of cervical neoplasia while the value of cytologic screening is limited due to a high prevalence of inflammatory disease. The study was conducted to determine whether testing for human papillomavirus (HPV) DNA could improve primary screening for cervical cancer of these patients. METHODS: One hundred thirty-eight HIV-infected women were examined between 1990 and 1998. Ninety-four patients with a total of 279 women-years were eligible for incidence evaluation. Colposcopy, cytology, and HPV DNA testing with the hybrid capture I assay were performed at each visit. RESULTS: Seventeen cases of high-grade cervical neoplasia were diagnosed at study entry and 13 developed CIN II or CIN III during follow-up. The hybrid capture I assay detected 94.1% of prevalent and 100% of incident high-grade neoplasia, while the corresponding sensitivity of Pap smears using CIN I or worse as the referral criteria was 82.3% for prevalent and 69.2% for incident high-grade neoplasia. Eleven of 13 patients who progressed to histologically confirmed CIN II/III tested positive for HPV DNA at study entry compared with 5/13 women presenting with any degree of cytologic atypia at recruitment. The Pap smears of 36/94 women remained normal throughout the study while 54/94 patients remained negative for high-risk HPV types. CONCLUSION: Hybrid capture I identified high-grade cervical neoplasia more accurately than the Pap smear and appeared to be beneficial for primary cervical cancer screening in HIV-infected women.


Assuntos
Infecções por HIV/virologia , Papillomaviridae/isolamento & purificação , Displasia do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/diagnóstico , Adulto , DNA Viral/análise , Feminino , Humanos , Pessoa de Meia-Idade , Teste de Papanicolaou , Prevalência , Estudos Prospectivos , Fatores de Tempo , Neoplasias do Colo do Útero/virologia , Esfregaço Vaginal , Displasia do Colo do Útero/virologia
9.
Brain Res ; 746(1-2): 151-63, 1997 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-9037494

RESUMO

Effects of L-glutamate, AMPA, NMDA and NPY on the discharge activity of neurons located in the ventral subdivision of the suprachiasmatic nucleus were examined in submerged coronal slices of the rat hypothalamus. All substances were bath applied. Application of L-glutamate (14 neurons examined) induced an excitatory response in 8 suprachiasmatic neurons (+248.9 +/- 122.24%, mean +/- S.E.M.; P < 0.001). A biphasic response, i.e. an initial transient excitation (+54.3 +/- 8.21%; P < 0.001) succeeded by an inhibition (-66.2 +/- 9.31%; P < 0.001), was observed in 6 neurons. Application of AMPA (36 neurons examined) resulted in an excitation of 31 neurons (+209.2 +/- 58.58%; P < 0.0001). Application of NMDA (57 neurons examined) induced an excitation in 34 neurons (+253.8 +/- 91.18%; P < 0.0001), but an inhibition in 8 neurons (-757 +/- 6.52; P < 0.0001). Biphasic effects of NMDA with an excitatory component (+58.7 +/- 9.94%; P < 0.0001) succeeded by an inhibitory component (-62.0 +/- 8.07%; P < 0.0001) were observed in 13 neurons. In 5 of 13 examined cases, the inhibitory component of neuronal responses to NMDA was significantly attenuated by the simultaneous application of strychnine (attenuation was 56%; P < 0.05). The application of NPY (40 neurons examined) induced significant effects on the discharge rate of 29 suprachiasmatic neurons. 18 of these neurons were inhibited (-59.3 +/- 6.39%; P < 0.0001) whereas 11 neurons were excited (+156.6 +/- 107.222%; P < 0.001) by NPY. In 8 of 11 neurons examined, the NPY-induced inhibition was significantly attenuated by 92% during simultaneous application of strychnine (P < 0.001). In 23 NPY-sensitive neurons, the discharge activity was also affected by NMDA. Neurons excited by NPY were also excited by NMDA (8 cells). In neurons inhibited by NPY, application of NMDA induced either an inhibition (3 cells) an excitation (5 cells) or a biphasic effect (7 cells). Results suggest a direct excitatory effect of AMPA, NMDA and NPY on suprachiasmatic neurons. In contrast, inhibitory actions of NMDA and NPY are considered induced by an activation of inhibitory interneurons. Antagonistic effects of strychnine suggest an involvement of glycinergic interneurons in a subpopulation of neurons inhibited by NMDA and in most neurons inhibited by NPY. The involvement of inhibitory mechanisms in photic entrainment of the circadian system is discussed. An integrative model of excitatory and inhibitory actions of EAA and NPY on suprachiasmatic neurons is proposed.


Assuntos
Ácido Glutâmico/farmacologia , Neurônios/efeitos dos fármacos , Neuropeptídeo Y/farmacologia , Núcleo Supraquiasmático/citologia , Animais , Ritmo Circadiano/efeitos dos fármacos , Relação Dose-Resposta a Droga , Eletrofisiologia , Agonistas de Aminoácidos Excitatórios/farmacologia , Glicinérgicos/farmacologia , Masculino , N-Metilaspartato/farmacologia , Neurônios/fisiologia , Técnicas de Cultura de Órgãos , Ratos , Ratos Sprague-Dawley , Estricnina/farmacologia , Núcleo Supraquiasmático/fisiologia , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologia
11.
Geburtshilfe Frauenheilkd ; 56(10): 509-12, 1996 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-9036061

RESUMO

A repeat Pap smear as well as a smear for human papillomavirus (HPV)-DNA detection with the Hybrid Capture assay (Digene diagnostics/Murex, Burgwedel) were collected from 30 women with Pap smears recurrently classified as "Pap III". All patients underwent colposcopy and histological assessment. The repeat Pap smear distinguished correctly in 15, colposcopy in 19 and the Hybrid Capture assay in 27 cases between neoplastic and inflammatory lesions. All invasive neoplasms were positive for HPV-DNA. HPV typing seems to be a suitable non-invasive method for early selection of cervical lesions that need histological assessment in women with smears classified as "Pap III".


Assuntos
DNA Viral/genética , Hibridização In Situ , Teste de Papanicolaou , Papillomaviridae/genética , Infecções por Papillomavirus/patologia , Infecções Tumorais por Vírus/patologia , Neoplasias do Colo do Útero/patologia , Esfregaço Vaginal , Adulto , Carcinoma in Situ/patologia , Colo do Útero/patologia , Sondas de DNA de HPV , Feminino , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Displasia do Colo do Útero/patologia
12.
Geburtshilfe Frauenheilkd ; 56(10): 513-6, 1996 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-9036062

RESUMO

100 patients with CIN on referral Pap and with a distinct cervical lesion on colposcopy were treated with the loop electrosurgical excisional procedure (LEEP). Compared with 60 women who underwent cold-knife conization, the number of lesions classified as CIN-3 or more did not differ between the two groups (53% vs 53.3%). Severe haemorrhage and cervical stenosis were only observed after conization. Involvement of resection margins was found in 18% of all LEEP and in 16.7% of all cone biopsies. 3-12 months after LEEP the rate of cytologically and biopsy proven neoplasia was 2.2%. LEEP is a safe and effective procedure and should be used as the treatment of choice for distinct cervical lesions.


Assuntos
Eletrocoagulação/instrumentação , Displasia do Colo do Útero/cirurgia , Neoplasias do Colo do Útero/cirurgia , Biópsia , Conização/instrumentação , Desenho de Equipamento , Feminino , Humanos , Estadiamento de Neoplasias , Papillomaviridae , Infecções por Papillomavirus/patologia , Infecções por Papillomavirus/cirurgia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/patologia , Infecções Tumorais por Vírus/patologia , Infecções Tumorais por Vírus/cirurgia , Neoplasias do Colo do Útero/patologia , Esfregaço Vaginal , Cicatrização/fisiologia , Displasia do Colo do Útero/patologia
13.
Aktuelle Traumatol ; 22(2): 47-56, 1992 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-1351341

RESUMO

Three-dimensional images of bone structures can easily be reconstructed from computed tomography data. The technique and the advantages of contemplating reconstructions of bone defects in different directions are described. A special software programme allows to combine all data which are given by the standard CT. The slice diameter is two millimetres. The reconstruction shows bone surfaces in all required views. In traumatic and orthopaedic surgery 3-D-CT is useful in the analysis, detection and preoperative planning of comminuted bone injuries of the spine, pelvis, knee, shoulder and the calcaneus. With this technique it is possible to see the bone in its topographic constellation, to observe fractures in unusual directions and to identify fragments from each other. The surgeon gets a lot of additional information which is helpful to decide on the incision, the reduction and the fixation of fragments. Undesirable effects during operation are reduced, which leads to a more accurate treatment and subsequent better results.


Assuntos
Acidentes , Fraturas Ósseas/diagnóstico por imagem , Processamento de Imagem Assistida por Computador , Traumatismo Múltiplo/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adulto , Simulação por Computador , Feminino , Fixação Interna de Fraturas , Fraturas Ósseas/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Traumatismo Múltiplo/cirurgia , Software
14.
Radiologe ; 32(2): 49-55, 1992 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-1314400

RESUMO

Chemoembolization is an effective treatment for hepatocellular carcinoma, giving results equally as good as surgical therapy for T2 tumours. Survival can be prolonged and side-effects can be reduced by combining Lipiodol and Gelfoam for chemoembolization, employing a modified technique, with repeated procedures, and using appropriate follow-up treatment. The toxicity of the procedure is acceptable, but it requires supportive therapy necessitating an intense interdisciplinary co-operation.


Assuntos
Carcinoma Hepatocelular/terapia , Quimioembolização Terapêutica , Epirubicina/administração & dosagem , Neoplasias Hepáticas/terapia , Idoso , Carcinoma Hepatocelular/epidemiologia , Feminino , Alemanha Ocidental/epidemiologia , Humanos , Neoplasias Hepáticas/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
15.
Neurosci Lett ; 130(2): 271-4, 1991 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-1686644

RESUMO

The action of endogenous excitatory amino acids on phrenic motoneurons was studied in anesthetized, vagotomized, paralyzed and artificially ventilated rabbits. The NMDA receptor antagonists APV and ketamine, as well as the non-NMDA receptor antagonists GAMS and DNQX were administered by microinjection into the ventral horn of the spinal segments C3-C5. Injection of each antagonist resulted in a reversible reduction of the phrenic nerve activity. Results suggest an important function of endogenous excitatory amino acids in the excitation of phrenic motoneurons. NMDA as well as non-NMDA receptors are involved. The functional role of both receptor types in bulbospinal neurotransmission is discussed.


Assuntos
Neurônios Motores/fisiologia , Nervo Frênico/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/fisiologia , 2-Amino-5-fosfonovalerato/administração & dosagem , 2-Amino-5-fosfonovalerato/farmacologia , Animais , Glutamina/administração & dosagem , Glutamina/análogos & derivados , Glutamina/farmacologia , Ketamina/administração & dosagem , Ketamina/farmacologia , Microinjeções , Neurônios Motores/efeitos dos fármacos , Quinoxalinas/administração & dosagem , Quinoxalinas/farmacologia , Coelhos , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Respiração/efeitos dos fármacos , Medula Espinal/efeitos dos fármacos , Sinapses/efeitos dos fármacos , Sinapses/fisiologia
16.
Acta Physiol Scand ; 142(3): 411-20, 1991 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1656705

RESUMO

The involvement of GABA mediated neurotransmission in the central control of respiration was investigated by administration of the specific GABAA receptor agonist muscimol and the specific GABAA receptor antagonist biculline into the fourth cerebral ventricle of the rabbit. Cycle-triggered averaging of the phrenic nerve activity (PNA) was used to quantify drug-induced changes of the central respiratory pattern. Muscimol reduced the peak amplitude of PNA and increased the duration of the respiratory phases. High amounts of muscimol led to a long-lasting but reversible central apnea. Bicuculline very effectively blocked the effects of externally applied muscimol. Blockade of intrinsically active GABAergic neurotransmission by bicuculline resulted in a multitude of effects. Peak amplitude of PNA increased whereas the duration of both inspiration and expiration decreased. In this respect, effects of bicuculline and muscimol were complementary. Bicuculline reduced the slope of the inspiratory ramp, increased postinspiratory activity and induced an augmenting type of discharge activity in the last part of expiration resulting in a smooth transition between expiration and inspiration. In some cases the respiratory modulation was completely lost and PNA became perfectly tonic. This 'apneustic' type of respiratory pattern could be transformed into rhythmic breathing by increasing the respiratory drive. We conclude that neurotransmission via GABAA receptors is important for the maintenance of respiratory rhythm as well as the generation of normal respiratory pattern.


Assuntos
Inibição Neural/fisiologia , Receptores de GABA-A/fisiologia , Centro Respiratório/fisiologia , Sinapses/fisiologia , Animais , Bicuculina/farmacologia , Trietiodeto de Galamina/farmacologia , Técnicas In Vitro , Injeções Intraventriculares , Muscimol/antagonistas & inibidores , Muscimol/farmacologia , Nervo Frênico/efeitos dos fármacos , Nervo Frênico/fisiologia , Coelhos , Respiração/efeitos dos fármacos , Transmissão Sináptica/fisiologia
17.
Respir Physiol ; 84(3): 351-61, 1991 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1656503

RESUMO

The involvement of glycinergic neurotransmission in the central regulation of respiration was investigated by administration of specific receptor agonists and antagonists into the 4th cerebral ventricle of the rabbit. Central respiratory activity was assessed by cycle-triggered averaging of phrenic nerve activity (PNA). Glycine reduced the peak amplitude of PNA and increased the duration of the respiratory phases. Conversely, strychnine decreased the duration of both phases, being more effective in expiration. Strychnine converted inspiratory ramp activity to a decrescendo type of pattern, with the highest discharge activity present at the onset of the inspiratory phase. Strychnine induced tonic PNA lasting throughout expiration with a decrescendo type of activity. In many cases strychnine induce apneusis with tonic PNA being at a level of about 2/3 of its maximum value during control. We conclude that glycinergic neurotransmission is important for the maintenance of the respiratory rhythm as well as the generation of normal respiratory pattern. Glycine could be involved in phasic as well as tonic inhibitory neurotransmission within the central respiratory system.


Assuntos
Tronco Encefálico/fisiologia , Glicina/metabolismo , Receptores de Neurotransmissores/metabolismo , Respiração/fisiologia , Sinapses/metabolismo , Animais , Injeções Intravenosas , Nervo Frênico/fisiologia , Coelhos , Receptores de Glicina , Estricnina/administração & dosagem , Estricnina/farmacologia
19.
Brain Res ; 528(1): 1-11, 1990 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-2123123

RESUMO

In urethane-anesthetized or decerebrated vagotomized rabbits efferent multifiber activity of the phrenic nerve was investigated for synchronized activities both in time and frequency domains. When respiratory drive was steadily increased by either an elevation of end-tidal CO2 concentration or i.v. administration of 4-aminopyridine, medium-frequency oscillations (MFO) first increased, then decreased and finally became absent. The power of high-frequency oscillations (HFO) steadily rose with increasing respiratory drive. In contrast to HFO which revealed a unimodal spectral peak of mostly small bandwidth, the MFO spectrum in most cases consisted of a broad complex. This complex in some cases was composed of two distinct peaks, i.e. MFO were heterogenous. The low- and high-frequency fractions of the MFO complex were related predominantly to the first and last third of inspiration, respectively. Examination of the on-going multifiber activity of the phrenic nerve with an expanded time scale revealed that lower frequency MFO probably result from synchronized ramp-like wave activity during early and mid-inspiration. The duration of the observed ramps well matched the corresponding MFO frequency. We suggest that these ramps might result from propagated synchronized waves of high-threshold phrenic motoneurons. During the last part of inspiration, however, MFO, like HFO, resulted from burst-like synchronized discharge of phenic motoneurons. Thus HFO are superimposed on ramp-like and burst-like activity of the MFO. It is assumed that the decline of MFO at high respiratory drive may be due to the increasing strength of HFO bursts which interrupt ramp activity in the MFO range and thus let MFO appear 'invisible' to the recording electrode. Both MFO and HFO were visually detectable in postinspiration.


Assuntos
Nervo Frênico/fisiologia , 4-Aminopiridina/farmacologia , Animais , Dióxido de Carbono , Vias Eferentes/fisiologia , Fibras Nervosas/fisiologia , Coelhos , Ratos , Ratos Endogâmicos , Respiração/efeitos dos fármacos , Respiração/fisiologia , Análise Espectral , Volume de Ventilação Pulmonar , Fatores de Tempo
20.
Neurosci Lett ; 116(1-2): 204-9, 1990 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-2259450

RESUMO

The role of serotonin (5-hydroxytryptamine, 5-HT)-mediated modulation of phrenic motoneuronal activity was evaluated by microapplication of 5-HT and methysergide into the phrenic nuclei of the rabbit. 5-HT facilitated phrenic nerve activity (PNA) considerably resulting in a long-lasting augmentation of the peak amplitude of integrated PNA. In contrast, the blockade of intrinsically active 5-HT by methysergide decreased PNA and led to a strong reduction of the peak amplitude of integrated PNA. MDL 72222 was ineffective. Blockade of 5-HT receptors by preceding administration of methysergide effectively abolished the effects of microinjected 5-HT. Respiratory timing was unaffected by both the agonist and the antagonist. These results suggest that a considerable portion of the facilitatory influence of caudal raphe nuclei on central respiratory activity takes place at the phrenic nuclei level.


Assuntos
Neurônios Motores/fisiologia , Nervo Frênico/fisiologia , Serotonina/farmacologia , Medula Espinal/fisiologia , Animais , Metisergida/farmacologia , Neurônios Motores/efeitos dos fármacos , Nervo Frênico/efeitos dos fármacos , Coelhos , Receptores de Serotonina/efeitos dos fármacos , Receptores de Serotonina/fisiologia , Valores de Referência , Antagonistas da Serotonina/farmacologia , Medula Espinal/efeitos dos fármacos , Fatores de Tempo , Tropanos/farmacologia , Vagotomia
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