RESUMO
Primary hyperparathyroidism is a clinical condition related to an excessive and abnormally regulated secretion of parathyroid hormone (PTH) from the parathyroid glands which is responsible for an alteration of the calcium and phosphorus metabolism. Parathyroid adenomas are the most important cause of primary hyperparathyroidism (80-85%). A case of parathyroid adenoma observed in a patient aged 47, admitted to the Emergency Medicine Department of our Hospital with a diagnosis of hypertensive crisis, cephalea, vomiting, and a clinical history of recurrent episodes of severe abdominal and renal pain, is presented. Lab data showed severe hypercalcemia and a progressive worsening of the renal function. A severe neurological involvement with stupor, derangement of mind, the arising of acute respiratory depression, lethargy compelled the colleagues to transfer him to the Intensive Care Unit; a neck ultrasonography showed a poor-echogenous area under the right thyroid inferior pole, with signs of vascularization. The suspect of a primary hyperparathyroidism related to a single adenoma of the parathyroid gland suggested a surgical treatment. A ''concise parathyroidectomy'' was performed. Our surgical approach was confirmed by the comparison of the preintervention and the post-intervention iPTH values: 2080 pg/mL (normal range: 12-65 pg/mL) before excision vs 101 pg/mL after the removal. The histologycal exam reported a parathyroid adenoma with large areas with haemorrage. Three days after surgery the patient was in good general conditions. Patients affected by primary hyperparathyroidism are often misdiagnosed because their clinical conditions can create differential diagnosis problems with other diseases. However the surgical option remains the gold standard treatment.
Assuntos
Adenoma/complicações , Hiperparatireoidismo Primário/etiologia , Neoplasias das Paratireoides/complicações , Adenoma/cirurgia , Erros de Diagnóstico , Humanos , Hiperparatireoidismo Primário/diagnóstico , Masculino , Pessoa de Meia-Idade , Neoplasias das Paratireoides/cirurgiaRESUMO
BACKGROUND/AIMS: The goal of the therapeutic management of patients affected by end-stage renal disease (ESRD) is to maintain the vascular access (VA) as long as possible. Myointimal hyperplasia development in the vascular walls of arteriovenous fistulas (AVFs) is considered one of the most important factors responsible for procedure failure. These alterations could be linked to hemodynamic changes in the anastomosis and to the presence of the surgical suture itself. We report our preliminary experience, discussing the use and the possible benefits of an absorbable suture in polyglycolide trimethylene carbonate (PTC) in AVF creation. METHODS: Seventy-four AVFs were created as primary access for hemodialysis (HD), using PTC, over 4 years. Age, gender, ESRD etiology, artery and vein preoperative diameters, AVF survival outcome, and the number of AVFs created per year were recorded. The Kaplan-Meier method was used to analyze AVF survival rates. RESULTS: No dehiscences, pseudoaneurysms, or failures in the 'critical' period related to PTC absorption were recorded. Kaplan-Meier analysis was used to evaluate AVF survival; 12-month primary AVF survival (74.33%) and AVF failure (25.67%) rates, 9 'early' (8.22%) and 10 'late' failures (13.51%), and a 360-day mean survival were found. CONCLUSIONS: Our data indicate that PTC, a well known and widely used material for sutures in vascular surgery, is safe and effective in AVF creation. Potential advantages of PTC sutures are represented by a reduced myointimal hyperplasia formation in the AVF vascular walls, prolonging the AVF lifespan and avoiding re-interventions.
RESUMO
BACKGROUND: Limitation of beta-cell growth after intraportal islet transplantation plays an important role in graft failure. To induce transplanted beta-cell proliferation, we studied the effect of compensatory liver growth in diabetic rats that had a subtherapeutic islet mass previously injected into the liver. METHODS: Syngeneic rats were used as islet donors or recipients; diabetes was induced by streptozocin. Three groups of streptozocin-treated rats were studied. In group 1, 250 islets were selectively transplanted into the posterior liver lobes and 10 days later anterior portal branch ligation (PBL) was performed (n = 18); in group 2, 250 islets were transplanted into the posterior lobes and 10 days later sham PBL was performed (n = 13); in group 3, rats underwent a sham transplantation and PBL (n = 6). Nonfasting blood glucose levels and body weight were monitored. Six rats in groups 1 and 2 were killed 48 hours after PBL, liver sections were stained for proliferating cell nuclear antigen, and islet cell labeling index was calculated. The remaining rats were killed 30 days later. Liver compensatory growth or atrophy was calculated and morphometric determination of beta-cell area was assessed on insulin-immunostained sections of the liver. RESULTS: In group 1 rats killed 48 hours after PBL, islet cell labeling index was significantly higher than in group 2 (p < 0.0001). After PBL, we observed normalization of nonfasting blood glucose levels in 10 of 12 rats. At 30 days, posterior liver lobes showed compensatory growth (218.5% +/- 18.6%) accompanied by atrophy of the anterior lobes; morphometric study of liver-engrafted islets showed a significant increase of individual beta-cell area, compared with group 2 (p < 0.0001). In groups 2 and 3, normoglycemia was not achieved. CONCLUSIONS: In streptozocin-diabetic rats, normoglycemia was restored after transplantation of a sub-therapeutic islet mass, followed by PBL-induced liver regeneration. Histologic and morphometric results indicating islet cell proliferation suggest that compensatory liver growth might have induced a hypertrophic/hyperplastic response in the intraportally transplanted beta-cells.
Assuntos
Glicemia/metabolismo , Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Experimental/cirurgia , Transplante das Ilhotas Pancreáticas/fisiologia , Regeneração Hepática , Animais , Divisão Celular , Diabetes Mellitus Experimental/sangue , Ilhotas Pancreáticas/citologia , Transplante das Ilhotas Pancreáticas/métodos , Fígado , Circulação Hepática/fisiologia , Masculino , Veia Porta/cirurgia , Antígeno Nuclear de Célula em Proliferação/análise , Ratos , Ratos Endogâmicos WF , Transplante Heterólogo/métodos , Transplante Heterólogo/fisiologia , Transplante IsogênicoRESUMO
The slow compensatory phases of the vestibulo-ocular reflex (VOR) in the rabbit tend to drift and the drift reverses the direction. This periodic alternating drift (PAD) has two peculiar characteristics: (1) it is induced by sinusoidal vestibular stimulation in naive animals, being evoked immediately after stimulus onset and persisting after the end of stimulation; (2) the peak velocity and period of the drift are dependent on stimulus amplitude. PAD of the rabbit has strong similarities with PAN, a periodic alternating nystagmus observed in humans with cerbellar disorders and in monkeys after nodulo-uvulectomy, although its peak velocity is smaller. It is hypothesized that PAD is due to a slight instability, caused by vestibular stimulation in darkness, of the cerebellar adaptive loop, which exerts a variable gain control on the time constant of the velocity storage integrator.
Assuntos
Movimentos Oculares/fisiologia , Reflexo Vestíbulo-Ocular/fisiologia , Vestíbulo do Labirinto/fisiologia , Animais , Relógios Biológicos/fisiologia , Cerebelo/fisiologia , Vias Neurais/fisiologia , Nistagmo Patológico/fisiopatologia , Estimulação Física , Coelhos , Núcleos Vestibulares/fisiologiaRESUMO
Early studies showed that compensatory liver growth after anterior portal branch ligation (aPBL) may restore normoglycemia in streptozotocin (STZ)-diabetic rats, in which a subtherapeutic islet mass was previously transplanted into the liver. We hypothesized that this effect could be related to islet regeneration at the graft site. This study was designed to characterize the proliferative response of the intraportally transplanted islets, shortly after aPBL. Male Wistar-Furth rats were used as syngeneic islet donors and/or recipients. STZ-diabetic rats were divided in four groups: groups 1 and 2 underwent selective 250-islet transplantation (Tx) into the posterior liver lobes, followed by aPBL 10 days later; rats were killed 24 h (n = 9) and 48 h (n = 10) after aPBL, respectively; groups 3 and 4 underwent selective 250-islet Tx into the posterior liver lobes, followed by sham aPBL 10 days later; rats were killed 24 h (n = 3) and 48 h (n = 3) after aPBL, respectively. Two hours before killing, all animals were injected with 5'-bromo-2'-deoxyuridine (BrdU; 50 mg/kg, i.v.). Liver sections were immunostained for insulin and BrdU, and both hepatocyte and islet cell labeling index (LI) were calculated. Islet cell LI was 2.30+/-1.18% in group 1, 2.23+/-1.00% in group 2, 0.43+/-0.29% in group 3, and 0.39+/-0.21% in group 4 (group 1 vs. group 3: p<0.02; group 2 vs. group 4: p<0.01). Hepatocyte LI was 2.50+/-2.14% in group 1, 15.0+/-7.6% in group 2, 0.12 +/-0.04 in group 3, and 0.11+/-0.03% in group 4, respectively (group 1 vs. group 2: p<0.02; group 1 vs. group 3: p<0.001; group 2 vs. group 4: p<0.001). Our study showed that intraportally transplanted islets undergo a concurrent proliferative response after aPBL, although with a lower extent and a different timing when compared with the liver-cell response.
Assuntos
Diabetes Mellitus Experimental/patologia , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas/citologia , Fígado/citologia , Pâncreas/citologia , Animais , Ductos Biliares/citologia , Glicemia , Bromodesoxiuridina , Divisão Celular , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/terapia , Ligadura , Regeneração Hepática , Masculino , Veia Porta , Ratos , Ratos Endogâmicos WFRESUMO
In order to investigate the mechanisms underlying the generation of steady-state responses (SSRs), auditory evoked potentials elicited by click trains presented at several stimulation rates (30, 40, 50, 60 Hz) were recorded in 7 awake rats by means of epidural electrodes placed over the temporal cortex. Mean amplitude-rate function calculated on the recorded responses appeared almost flat and showed the maximum value at 50 Hz, while mean phases showed a linear increase when increasing the stimulation rate. In each rat, predictions of the recorded responses at 30, 40, 50 and 60 Hz were synthesized by superimposing middle-latency auditory evoked potentials (MAEPs) at suitable time intervals at each rate. Mean amplitudes calculated on the predicted curves decreased linearly when increasing the stimulation rate and appeared higher in comparison to those obtained from the recorded SSRs. Predicted phases showed a linear increase when increasing the stimulation rate and were leading with respect to corresponding phase values calculated for recorded SSRs. Our findings indicate that the MAEP superimposition mechanism does not adequately predict the generation of temporal recorded SSRs in rats. This was explained by admitting that phenomena related to the recovery cycle and, to a lesser extent, to rate-dependent facilitating effects come into play.
Assuntos
Potenciais Evocados Auditivos/fisiologia , Lobo Temporal/fisiologia , Estimulação Acústica , Animais , Masculino , Ratos , Ratos Wistar , Tempo de Reação/fisiologiaRESUMO
We demonstrated in vitro that the colonic peristaltic activity is modified in dystrophin-deficient mdx mouse indicating a defect in the enteric nervous system (ENS). Since nitric oxide (NO) has been proposed as a putative inhibitory mediator of ENS, here we have examined the effects of both L-Arginine (L-Arg) and Nomega-nitro-L-arginine methyl ester (L-NAME) on the peristaltic activity of mdx mouse distal colon. The motor pattern of colonic segment showed irregular peristaltic waves. L-Arg (10(-7) - 10(-5) M) induced the peristaltic activity to slow down. At a concentration of 10(-5) M, L-Arg produced hypomotility, characterised by a decrease in amplitude, frequency and ejected fluid volume. Conversely, L-NAME elicited hypermotility, this effect being reversed once again by the subsequent addition of L-Arg. Interestingly the addition of 10(-5) M L-Arg to the organ bath led to the normal progression, in an oral to aboral direction, of 90% of the peristaltic waves. This last result strongly suggests that exogenous application of L-Arg restores the integrative circuits of the ENS responsible for programming and co-ordinating peristaltic activity in the distal colon of mdx mouse.
Assuntos
Colo/fisiologia , Distrofia Muscular Animal/metabolismo , Óxido Nítrico/metabolismo , Peristaltismo/fisiologia , Animais , Arginina/farmacologia , Colo/inervação , Sistema Nervoso Entérico/fisiologia , Inibidores Enzimáticos/farmacologia , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos mdx , Neurônios Motores/fisiologia , Músculo Liso/efeitos dos fármacos , Músculo Liso/inervação , Músculo Liso/fisiologia , NG-Nitroarginina Metil Éster/farmacologia , Peristaltismo/efeitos dos fármacosRESUMO
Nitric oxide (NO) is a short-lived radical species endowed with intercellular signalling functions in the mammalian brain. In the present study we have investigated the effects of focal injection into one inferior colliculus of N omega-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, on the acoustic middle latency responses (MLRs) evoked by click stimuli and recorded from the auditory cortex in anaesthetized rats. Microinfusion of L-NAME (1.0 mM) did not alter the latency of MLRs nor did it affect the evoked brain stem responses (ABRs). By contrast, L-NAME reduced P1a-N1 amplitude of MLRs by 51.7 +/- 6.6% (mean +/- SEM; n = 5) and almost complete recovery to background amplitude was obtained 15-25 min after treatment. The less active isomer, D-NAME (1.0 mM; n = 5), failed to produce consistent effects on the evoked MLRs. A higher concentration of L-NAME (5.0 mM; n = 5) yielded a 69.0 +/- 13.3% inhibition whereas maximum inhibition produced by 0.5 mM (n = 3) L-NAME was approximately equal to 10% of control value. The inhibitory effect typically evoked by 1.0 mM L-NAME was prevented by treating rats with L-arginine (5.0 mM; n = 5), the endogenous precursor of NO synthesis. Reduction of MLR amplitude was also obtained in rats receiving intracollicular injection of dizocilpine (MK801; 1.0 microM) and LY274614 (1.0 mM), two selective N-methyl-D-aspartate (NMDA) receptor antagonists. In conclusion, the present data support a role for intracollicular NO in the processing and transmission of the acoustic input to the auditory cortex in the rat.
Assuntos
Arginina/análogos & derivados , Inibidores Enzimáticos/farmacologia , Potenciais Evocados Auditivos do Tronco Encefálico/efeitos dos fármacos , Colículos Inferiores/efeitos dos fármacos , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico/fisiologia , Estimulação Acústica , Animais , Arginina/farmacologia , Maleato de Dizocilpina/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Isoquinolinas/farmacologia , Masculino , NG-Nitroarginina Metil Éster , Fármacos Neuroprotetores/farmacologia , Ratos , Ratos Wistar , Tempo de Reação/fisiologiaRESUMO
Experiments have been carried out in isolated distal colon of young normal and mdx dystrophic mice, the animal homologous of Duchenne muscular dystrophy. Intraluminal pressure, longitudinal displacement, ejected fluid volume and changes in morphology during peristaltic events were recorded. In both male and female normal animals, pressure waves were observed to be generally regular in shape, amplitude (14.19 +/- 2.45 (SD) cm H2O), frequency (54.00 +/- 10.78 h-1) and duration (31.12 +/- 3.47 s). The propulsive activity resulted in orthograde transport of intraluminal content. Mdx mice exhibited great changes in relation to sex, since clear and more marked dysfunctions were recorded in female mice. In male mdx animals, an increase of intraluminal pressure (22%) and ejected fluid volume (38%) were recorded. In females, a remarkable significant (P < 0.001) increase (78%) of intraluminal pressure was observed. Simultaneous anterograde and retrograde propulsive activity also occurred. Localized annular constrictions in proximal, central and distal portions of colonic segment were observed. The implications of the results are discussed in terms of injury of myogenic and nervous pathways controlling mdx colonic smooth muscle.
Assuntos
Distrofia Muscular Animal/fisiopatologia , Peristaltismo/fisiologia , Reflexo/fisiologia , Animais , Colo/fisiologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos mdx , Músculo Liso/fisiologia , Distrofia Muscular Animal/genéticaRESUMO
A possible functional role of inducible isoform of nitric oxide synthase (iNOS) was explored in vitro on the motility of mouse distal colon. Using an isotonic - non-isovolumic technique, peristaltic activity and video images of the external wall of colonic segments were recorded before and after addition to the medium of Aminoguanidine (AG) and N-(3-(aminomethyl)benzyl) acetamidine (W1400) [10(-7) M-10(-4) M], two iNOS inhibitors. AG and W1400 induced an hyperexcitability of visceral smooth muscle characterised by an increase of basal tone and spontaneous phasic activity. As a consequence of these effects, the peristaltic activity declined and disappeared at the highest concentrations. These findings indicated a removal of inhibitory action performed by NO synthesised by iNOS in the colonic segment. The implications of results are discussed in term of tonic relaxation of intestinal smooth muscle to allow intraluminal content accommodation.
Assuntos
Colo/enzimologia , Motilidade Gastrointestinal/fisiologia , Músculo Liso/enzimologia , Óxido Nítrico Sintase/metabolismo , Amidinas/farmacologia , Animais , Benzilaminas/farmacologia , Inibidores Enzimáticos/farmacologia , Guanidinas/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase Tipo IIRESUMO
Stimulation of the cervical sympathetic nerve at 10/s increases by 12.9 +/- 0.7% peak tension of maximal twitches in the directly stimulated jaw muscles and markedly depresses (41.6 +/- 1.3%) the tonic vibration reflex (TVR) elicited in the same muscles by vibration of the mandible. Both effects are not significantly influenced by administration of beta-adrenoceptor antagonists. When both alpha- and beta-adrenergic receptors are blocked, sympathetic stimulation induces a very small increase in twitch tension (3.8 +/- 0.7%), while no detectable change in the TVR is observed. Close arterial injection of alpha 1-adrenoceptor agonist phenylephrine mimics the effects induced by sympathetic stimulation on twitch tension and TVR, dose-dependently. The noradrenaline co-transmitter neuropeptide Y also produces a long-lasting, dose-dependent increase in the twitch tension which is unaffected by blockade of adrenergic receptors as well as of the neuromuscular junctions. Contribution of neuropeptide Y to the sympathetically-induced reduction of the stretch reflex is not clearly demonstrated. These data suggest that co-operation between noradrenaline and neuropeptide Y may be effective in determining sympathetic modulation of skeletal muscle function.
Assuntos
Arcada Osseodentária/fisiologia , Músculo Esquelético/fisiologia , Neuropeptídeo Y/fisiologia , Norepinefrina/fisiologia , Sistema Nervoso Simpático/fisiologia , Animais , Relação Dose-Resposta a Droga , Fenilefrina/farmacologia , CoelhosRESUMO
The effects of N-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, were examined on Mg2+-free-induced epileptiform activity, in guinea-pig piriform cortex slices in vitro. L-NAME (0.1-1 mM) had no effect on neuronal membrane properties or electrically-evoked postsynaptic potentials (PSPs). In contrast, during superfusion of the slices with Mg2+-free solution neurones exhibited spontaneous and stimulus-evoked epileptiform potentials that were suppressed in the presence of L-NAME (100 microM) or the selective NMDA receptor antagonist DL-APV (100 microM). The inhibitory effects induced by L-NAME were reversibly reduced by L-arginine (1 mM), but not D-arginine (1 mM), the latter drug not being a substrate for NO formation. It was concluded that L-NAME can suppress epileptiform activity induced by Mg2+-free exposure primarily through a decrease in presynaptic transmitter release, although additional actions on the NMDA-receptor complex were also considered.
Assuntos
Córtex Cerebral/efeitos dos fármacos , Epilepsia/tratamento farmacológico , NG-Nitroarginina Metil Éster/farmacologia , Neurônios/efeitos dos fármacos , Óxido Nítrico Sintase/efeitos dos fármacos , Animais , Feminino , Cobaias , Técnicas In Vitro , Magnésio/farmacologia , MasculinoRESUMO
The effects of the cannabinoid receptor agonist Win 55,212-2 and of the competitive cannabinoid receptor antagonist SR 141716A on the electrically-evoked peristalsis of isolated distal colon of mouse were studied. Intraluminal pressure, longitudinal displacement, ejected fluid volume and changes in morphology of external intestinal wall were simultaneously recorded in the pre-drug period and in presence of Win 55,212-2 alone or in combination with SR 141716A. In the pre-drug period (control), peristaltic activity was characterised by regular, monophasic waves and the intraluminal content propelled towards anterograde (oro-aboral) direction with a propulsion velocity of 1.25 +/- 0.1 mm x s(-1). Pressure and shortening waves showed a peak amplitude of 2.44 +/- 0.32 kPa and 1.8 +/- 0.72 mm, respectively. The mean amount of fluid volume ejected during each contraction was 80 +/- 12.6 microl. The addition of Win 55,212-2 [10(-7)-10(-4) M] to the organ bath determined a dose-related attenuation of peristaltic activity consequent to the decrease of circular and longitudinal muscle strength. The decrease of contractile activity was followed by dose-dependent decrease of the amount of fluid ejected during peristalsis. The effects of Win 55,212-2 [10(-7)-10(-5) M] were prevented by SR 141716A, indicating the presence of cannabinoid CB1 receptors in the mouse distal colon. SR 141716A alone enhanced both tonic and phasic motor activities in the colonic longitudinal smooth muscle, suggesting that CB1 receptor antagonists could act either through antagonising the effect of endogenous CB1 receptor agonist or by an agonist effect on these receptors. The present results further support the hypothesis that cannabinoids perform a neuromodulatory role in various tracts of gastrointestinal system and first demonstrate their action also in the distal colon of rodents.
Assuntos
Canabinoides/farmacologia , Colo/fisiologia , Morfolinas/farmacologia , Naftalenos/farmacologia , Peristaltismo/efeitos dos fármacos , Piperidinas/farmacologia , Pirazóis/farmacologia , Animais , Benzoxazinas , Canabinoides/antagonistas & inibidores , Colo/citologia , Colo/efeitos dos fármacos , Interações Medicamentosas , Estimulação Elétrica , Potenciais Evocados/efeitos dos fármacos , Potenciais Evocados/fisiologia , Técnicas In Vitro , Masculino , Camundongos , Camundongos Endogâmicos ICR , Músculo Liso/citologia , Músculo Liso/efeitos dos fármacos , Músculo Liso/fisiologia , RimonabantoRESUMO
The spontaneous electrical activity of single mesencephalic and bulbar neurons was recorded in hemispherectomized rats, following topical application of the GABA-antagonist penicillin-G on the mesencephalon or on the rhombencephalon, to investigate whether these structures could develop a specific penicillin paroxysmal activity independently of the upper structures. Twenty minutes following penicillin-G, the mesencephalic neurons developed paroxysmal activity characterized by a significant increase in the spontaneous electrical activity, the appearance of multiunit activity and, frequently, phasic activity with rhythmical outbursts. The paroxysmal activity at bulbar level appeared later than that observed in the mesencephalon and was characterized by a significant increase of the spontaneous firing rate of the neurons, single short bursts and sometimes rhythmical outbursts. The bulbar outbursts always discharged at lower frequency than those at the mesencephalic level. Following a midcollicular transection the paroxysmal bulbar activity abruptly disappeared. This phenomenon might be explained by a loss of facilitation from superior structures on the bulbar neurons which in roditors show a poor GABA-receptor distribution. In other words, penicillin alone, due to the scarcity of GABA receptors, might not be sufficient to induce paroxysmal activity in bulbar neurons but the simultaneous presence of both the superior facilitation and the drug might enhance neuronal excitability to a critical level. However, the diffusion of the drug upwards to the mesencephalon, with consequent activation of a system allowing the downward propagation of paroxysmal activity, cannot be excluded. In conclusion, while the mesencephalic neurons demonstrate a proper ability to develop penicillin paroxysmal discharge, the bulbar neurons must be sustained by intact connections with upper structures to be able to do so.
Assuntos
Tronco Encefálico/efeitos dos fármacos , Eletroencefalografia/efeitos dos fármacos , Mesencéfalo/efeitos dos fármacos , Penicilina G/farmacologia , Animais , Potenciais Evocados/efeitos dos fármacos , Bulbo/efeitos dos fármacos , Vias Neurais/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Ratos , Formação Reticular/efeitos dos fármacosRESUMO
Auditory evoked responses were recorded in 16 normally hearing subjects in order to investigate the mechanisms underlying the generation of the 40 Hz steady-state response (SSR). In the first part of our study, auditory potentials were evoked by 0.1 ms clicks presented at 105 dB p.e. SPL with repetition rates of 7.9 (to obtain middle latency response, MLR), 20, 30, 40, 50, 60 Hz. In each subject predictions of the responses recorded at stimulus repetition rates of 30, 40, 50, 60 Hz were synthesized by superimposing MLRs at suitable time intervals. The calculated mean amplitude/rate and phase/rate functions behaved similarly for the recorded and predicted curves, showing the highest amplitude at 40 Hz and a linear increase of phase values when increasing the stimulus rate. Nevertheless the synthetic curves closely predicted amplitude and phase values of the recorded responses only at 40 Hz. At frequencies below 40 Hz, the mean amplitude of the predicted curve was lower than that of the recorded one while at frequencies above 40 Hz the mean amplitude was higher. Predicted phase values were found lagging at 30 Hz, and leading at 50 Hz and 60 Hz in comparison to phase values calculated on the recorded responses. Our findings suggest that a model based on the linear addition of transient MLRs is not able to adequately predict steady-state responses at stimulus rates other than at 40 Hz. Other mechanisms related to the recovery cycle of the activated system come into play in the steady-state response generation causing a decrease in amplitude and an increase in phase lag when increasing the stimulus repetition rate.
Assuntos
Córtex Auditivo/fisiologia , Potenciais Evocados Auditivos/fisiologia , Estimulação Acústica , Adulto , Limiar Auditivo/fisiologia , Eletroencefalografia , Feminino , Análise de Fourier , Humanos , Masculino , Análise de RegressãoRESUMO
Excellent results with respect to preservation of the limb and improvement of claudication were obtained with profundaplasty in 29 patients with Fontaine's stage III or IV chronic obliteration. The method is regarded as one of choice for saving the limb, but not as a replacement for other methods of direct revascularisation of the femoropopliteal axis in cases where complete functional recovery is also required. A comparison is made between the results of profundaplasty and reconstruction of the axis in a personal series.
Assuntos
Arteriosclerose/cirurgia , Artéria Femoral/cirurgia , Perna (Membro)/irrigação sanguínea , Amputação Cirúrgica , Prótese Vascular , Endarterectomia , Seguimentos , Humanos , Métodos , Trombose/etiologiaRESUMO
Abdominal aortic aneurysm (AAA) repair associated with a pelvic kidney is extremely rare. To date only 14 cases have been reported in the literature. The main problem during aortic cross clamping is kidney preservation. The purpose of this article is to record and additional case of AAA repair associated with a native pelvic kidney. The preservation has been successfully achieved by a distal aortic double clamping.
Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Rim/anormalidades , Idoso , Aneurisma da Aorta Abdominal/complicações , Constrição , Humanos , MasculinoRESUMO
Hepatic support is indicated in acute liver failure (ALF) patients to foster liver regeneration, or until a liver becomes available for orthotopic liver transplantation (OLT), in primary non function of the transplanted liver, and hopefully in chronic liver disease patients affected by ALF episodes, in whom OLT is not a therapeutic option. The concept of bioartificial liver (BAL) is based on the assumption that only the hepatocytes can perform the whole spectrum of biotransformation functions, which are needed to prevent hepatic encephalopathy, coma and cerebral edema. Among others, two important issues are related to BAL development: 1) the choice of the cellular component; 2) the cell mass needed to perform an adequate BAL treatment. Primary hepatocytes, of human or animal origin, should be considered the first choice because they express highly differentiated functions. Accordingly, a minimal cell mass corresponding to 10% of a human adult liver, i.e. 150 grams of freshly isolated, > or = 90% viable hepatocytes should be used. When 4 degrees C cold-stored or cryopreserved hepatocytes are used, the cellular mass should be increased because of a drop in cell viability and function. In case of hepatoma-derived cells, cultured cell lines or engineered cells, an adequate functional cell mass should be used, expressing metabolic and biotransformation activities comparable to those of primary hepatocytes. Finally, the use of porcine hepatocytes or other animal cells in BAL devices should be presently directed only to ALF patients as a bridge treatment to OLT, because of potential transmission of animal retrovirus and prions which may potentially cause major pandemics.
Assuntos
Hepatócitos , Fígado Artificial , Animais , Contagem de Células , Linhagem Celular , Sobrevivência Celular , Células Cultivadas , Hepatócitos/metabolismo , Humanos , Falência Hepática Aguda/terapia , Consumo de Oxigênio , Suínos , Preservação de TecidoRESUMO
Orthotopic liver transplantation (OLT) is the only effective therapeutic modality in severe acute hepatic failure (AHF). The scarcity of organs for transplantation leads to an urgent necessity for temporary liver support treatments in AHF patients. A hepatocyte-based bioartificial liver (BAL) is under investigation with the main purpose to serve as bridging treatment until a liver becomes available for OLT, or to promote spontaneous liver regeneration. We developed a novel radial-flow bioreactor (RFB) for three-dimensional, high-density hepatocyte culture and an integrated pumping apparatus in which, after plasmapheresis, the patient's plasma is recirculated through the hepatocyte-filled RFB. Two hundred thirty grams of freshly isolated porcine hepatocytes were loaded into the RFB for clinical liver support treatment. The BAL system was used 8 times in supporting 7 AHF patients in grade III-IV coma, all waiting for an urgent OLT Three patients with no history of previous liver diseases were affected by fulminant hepatic failure (FHF) due to hepatitis B virus, 3 by primary non-function (PNF) of the transplanted liver, and one by AHF due to previous abdominal trauma and liver surgery. Six out of 7 patients underwent OLT following BAL treatment(s), which lasted 6-24 hours. All patients tolerated the procedures well, as shown by an improvement in the level of encephalopathy, a decrease in serum ammonia, transaminases and an amelioration of the prothrombin time, with full neurological recovery after OLT Our initial clinical experience confirms the safety of this BAL configuration and suggests its clinical efficacy as a temporary liver support system in AHF patients.
Assuntos
Falência Hepática Aguda/terapia , Fígado Artificial , Adolescente , Adulto , Animais , Sobrevivência Celular , Células Cultivadas , Circulação Extracorpórea , Feminino , Hepatócitos/metabolismo , Humanos , Transplante de Fígado , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio , SuínosRESUMO
Nerve and cortical input convergence patterns, representing the fore- and hindlimb, were studied in single cells located in the lateral vestibular nucleus of the cat. Deitersian cells responded with excitation to cortical stimulation with a latency ranging from 4 to 14 msec, while responses ranged from 9 to 12 msec to radial nerve stimulation and from 14 to 18 msec to sciatic nerve stimulation. Lateral vestibular nuclear neurons responding to radial nerve stimulation also receive the main cortical input from the sensorimotor cortical area concerned with the forelimb. Neurons responding to sciatic nerve stimulation receive an equal cortical input from both fore- and hindlimb areas of the sensorimotor cortex. In a few cells different combinations of convergence of cortical and peripheral inputs were also observed.