Clinical and electrophysiological correlation in chronic inflammatory demyelinating polyneuropathy with intravenous immunoglobulin therapy: a case report

The clinical effect of high-dose intravenous immunoglobulin (IVIg) is reported as correlated with electrophysiological study in a 15-year-old boy with chronic inflammatory demyelinating polyneuropathy (CIDP). Within three months the patient developed from progressive paraparesis to complete quadriplegia with relative preservative of sensory and bulbar functions. High dose IVIg with 0.4 gm/kg per day was given for five consecutive days, and recovery occurred during the first week, particularly in both the lower limbs. Maximal benefit was achieved by another course of IVIg treatment. The effect maintained for six weeks, but muscle power deteriorated rapidly one week later. Muscle power improved again after another two courses of IVIg infusion. Serial nerve conduction velocity studies showed an improvement in the distal latencies and the amplitudes of compound muscle action potentials (CMAPs) which were not, however, well correlated with the clinical improvement. No improvement in nerve conduction velocities was ever noted.

Coenzyme Q10 treatment in mitochondrial encephalomyopathies. Short-term double-blind, crossover study

We report a short-term double-blind, crossover study of CoQ10 in 8 patients with mitochondrial encephalomyopathies. Four patients had myoclonus epilepsy with ragged-red fibers syndrome, 3 had mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes syndrome, and 1 had chronic progressive external ophthalmoplegia with myopathy. A trend of effectiveness of CoQ10 in several parameters was noted. Fatigability of daily activities was alleviated. The endurance to muscle exercise was augmented. Global muscle strength scored by Medical Research Council scale was increased. The extent of elevation in serum lactate and pyruvate levels after exercise was decreased. However, only the global MRC index score had a statistical significance (p < 0.05). There were no side effects during therapy. The serum CoQ10 levels were significantly lower in patients than in normal controls before CoQ10 treatment and increased significantly after treatment.

Blue toe syndrome associated with rapidly progressive glomerulonephritis: ultimately revealed essential mixed cryoglobulinemia

The blue toe syndrome is a rare presentation in a number of medical disorders. We report a 35-year-old woman who initially presented with blue toe syndrome and rapidly progressive glomerulonephritis. Essential mixed cryoglobulinemia with vasculitis and renal failure was documented by laboratory tests and renal biopsy. She was on maintenance hemodialysis as renal failure persisted after steroid and immunosuppressive agents therapy. Her gangrenous changes of bilateral toes were autoamputated symmetrically and uneventfully.

Hemostatic and fibrinolytic response to desmopressin in uremic patients

Desmopressin (DDAVP) 0.3 micrograms/kg was infused in 20 uremic patients with prolong bleeding time. Prior to infusion, the uremic patients had a reduced level of tissue plasminogen activator (t-PA), normal levels of von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor activity (vWF:RCo) and elevated level of factor VIII coagulant activity (FVIII:C). Patients with lower hematocrit or t-PA levels tended to have a longer bleeding time. One hour after DDAVP infusion, the bleeding time was shortened significantly. This improvement was significant in all patient groups irrespective of the high or low initial levels of factor VIII complex components. Plasma levels of FVIII:C, vWF:Ag, vWF:RCo and t-PA all increased significantly. The magnitude of increase in these factors, however, was not significantly correlated with the extent of bleeding time shortening. The multiple regression model for predicting the extent of bleeding time shortening suggested only two variables, viz initial bleeding time and posttreatment FVIII:C activity to be of significance. The present results indicate that the hemostatic response to DDAVP is uniform in uremic patients, regardless of whether the initial activities of factor VIII complex components are high or low. Posttreatment FVIII:C activity appears to play a significant role in the hemostatic action of DDAVP. Furthermore, a depressed fibrinolytic activity was generally observed to concur with the hemostatic defect in uremic patients.

Peripheral neuropathy in mitochondrial encephalomyopathies

Seven patients with mitochondrial encephalomyopathies were studied for peripheral neuropathy by clinical, electrophysiological and pathological examinations. The clinical manifestation of neuropathy varied from asymptomatic to mild and moderate sensorimotor symptoms with painful paresthesia. Five patients (2 with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes, and 3 with myoclonic epilepsy and ragged-red fibers, MERRF) had clinical symptoms and signs of polyneuropathy associated mainly with decreased amplitudes of the compound muscle or nerve action potentials in an electrophysiological study indicating axonal degeneration. Sural nerve biopsy from 1 MERRF patient, also confirmed an axonal degeneration with reduction of large myelinated fibers. Mitochondrial DNA analysis of the sural nerve from this patient showed a point mutation from A to G transition at the nucleotide position 8344 with 80% mtDNA mutation. The results of this study suggest that peripheral neuropathy is not uncommon in mitochondrial encephalomyopathies and is predominantly due to axonal degeneration.

Effects of occupational dust exposure on the respiratory health of Portland cement workers

The object of this study was to assess the relationship between occupational Portland cement dust exposure and respiratory health. Respiratory symptoms and ventilatory function were studied in a group of 591 male Portland cement workers employed in four cement plants. The prevalence of chronic respiratory symptoms was higher in exposed than in control workers. The exposed group had a significantly lower mean forced vital capacity (FVC), forced expiratory volume at 1 s (FEV1), and forced expiratory flows after exhalation of 50% and 75% of the vital capacity (FEF50, FEF75) than the control group. The data suggest that occupational exposure to Portland cement dust may lead to higher prevalence of chronic respiratory symptoms and the reduction of ventilatory capacity.

Inhibition of calcium channels in rat hippocampal CA1 neurons by conantokin-T

Effects of conantokin-T, a 21 amino acid peptide toxin isolated from the fish-hunting cone snail Conus tulipa, on the high-voltage-activated Ca2+ channel currents were studied in acutely dissociated rat hippocampal CA1 neurons using whole-cell voltage clamp-recording technique with 5 mM Ba2+ as the charge carrier. Conantokin-T inhibited the whole-cell Ba2+ current (IBa) in a concentration-dependent manner. The nimodipine (20 microM) and omega-agatoxin-IVA (0.2 microM) block of IBa were abolished in the presence of conantokin-T (3 microM); however, conantokin-T (3 microM) did not affect the block of IBa induced by 3 microM omega-conotoxin-GVIA. These results indicate that conantokin-T is a potent but wide-spectrum Ca2+ channel antagonist.

Peritoneal nitric oxide is a marker of peritonitis in patients on continuous ambulatory peritoneal dialysis

Nitric oxide plays an important role in mediating the inflammatory process. The aim of this study was to evaluate if nitric oxide production was increased during peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD), and the association with the prognosis. The study population comprised 21 patients with 22 episodes of peritonitis. Fifteen patients without peritonitis were controls. Nitrate was measured by HPLC and nitrite by the Griess method, to reflect nitric oxide production. Peritoneal dialysate effluent and plasma were collected from six patients during peritonitis and 1 week after treatment to study changes in dialysate:plasma ratio. In 15 patients, nitrite was measured during peritonitis and every 3 days for 2 weeks or until normalized for evolutional changes. The dialysate:plasma ratios of nitrate and nitrite during peritonitis were reduced 26% and 41.5%, respectively, after 1 week of treatment, indicating the peritoneal production of nitric oxide during peritonitis. In the evolutional study, a 5.1-fold increase of peak nitrite levels in bacterial peritonitis (n = 13) and a 2.5-fold increase in fungal peritonitis (n = 3) were observed compared to controls. Nitrite gradually declined to control levels (9.3 +/- 7.2 days) after effective antibiotic treatment, but took longer than to normalize leukocyte count in the peritoneal dialysate effluent (3.9 +/- 1.9 days). In four patients with refractory peritonitis (Candida infection in three, Acinetobacter infection in one), the nitrite levels remained elevated 2-fold despite treatment, and the catheters were removed. It is concluded that nitrite levels in peritoneal dialysate effluent may serve as a marker to assess treatment efficacy in CAPD patients with peritonitis.

Cholera associated with acute renal failure and rhabdomyolysis: a case report

While cholera is not endemic in Taiwan, the number of imported cases is increasing. We report a 59-year-old Taiwanese male who developed severe diarrhea and vomiting, two days after returning from Bali. The patient admitted drinking a beverage with ice purchased from a street vendor. On admission he was weak and dehydrated. The patient suffered from hypovolemic shock and acute renal failure. Elevated creatine phosphokinase indicated rhabdomyolysis. Fluid replacement with Ringer's lactate solution was instituted. Dyspnea and pulmonary edema developed, and hemodialysis was begun to remove excess fluid due to decreased urinary output. Isolation of Vibrio cholerae O1 from stool confirmed the diagnosis of cholera, and doxycyline was begun. The patient's condition stabilized, with increased urinary output, and resolution of diarrhea, vomiting and dyspnea. Cholera, although rare in Taiwan, can be lethal if left untreated. Rapid intervention with fluid replacement is essential to prevent hypovolemic shock and circulatory collapse in severe cases.

A new approach to the treatment of true-combined endodontic-periodontic lesions by the guided tissue regeneration technique

Clinicians often have difficulty in the diagnosis and treatment of the combined endodontal and periodontal (endo-perio) lesion. A case of an endo-perio true-combined lesion on a maxillary premolar was first treated with conventional endodontic therapy. Periodontal surgery was then completed, which included scaling and root planing and apical curettage on the tooth. The facial bony defect was then filled with a decalcified freeze-dried bone allograft mixed with tetracycline powder. A non-resorbable Teflon membrane was then used to cover the bone material and the periodontal flap sutured over this. This combined treatment resulted in minimal probing depth (2 mm), maximal clinical attachment gain (8 mm), as well as radiographic evidence of alveolar bone gain. This case report demonstrates that proper diagnosis, followed by removal of etiological factors and utilizing the guided tissue regeneration technique combined with osseous grafting, will restore health and function to a tooth with severe attachment loss caused by an endo-perio lesion.

Inhibition of N-type calcium currents by lamotrigine in rat amygdalar neurones

Lamotrigine (LAG) is a new anticonvulsant drug for the treatment of partial and secondarily generalized seizures. The present study was aimed at elucidating the possible involvement of Ca2+ channels in the action of LAG using whole-cell patch clamp recordings in acutely dissociated amygdalar neurones. Whole-cell Ca2+ currents (ICa) were elicited by 200 ms step commands from -70 mV to -10 mV. Application of LAG reduced the ICa by an average of 40.3 +/- 3.2%. The inhibition of ICa by LAG was markedly reduced or eliminated in the presence of the N-type Ca2+ channel blocker omega-conotoxin-GVIA (1 microM). These results suggest that LAG may exert its anticonvulsant effect through inhibition of presynaptic N-type Ca2+ channels, thereby reducing glutamate release.

The effects of induced apneic episodes on cerebral cortical oxygenation in newborn piglets

The effect of different inspiratory oxygen levels (FiO2) on cortical oxygenation (pO2) during and after recovery from apnea, was investigated in 18 anesthetized, paralyzed, and mechanically ventilated newborn piglets. Heart rate (HR) and mean arterial blood pressure (MABP) were continuously monitored as the piglets were subjected to repeated episodes of apnea initiated by disconnecting the ventilator and terminated when HR decreased to less than 80 beats/min by reconnecting the ventilator. A closed cranial window was placed over the parietal cortex of the animals and cortical pO2 was measured optically by phosphorescence quenching. Apneic episodes induced in animals ventilated with 15%, 22% and 40% oxygen had mean duration's of apnea (time before HR decreased to less than 80 beats/min) of 80, 128 and 134 s, respectively. By the end of the apnea the MABP decreased to 82%, 64%, and 54% of control, respectively. The cortical pO2 decreased from control values of 24.1, 32.3 and 38.3 Torr at 15%, 22% and 40% oxygen, respectively, to 1.7 to 3.2 Torr at the end of the apneic episode. The duration of apnea necessary for the cortical pO2 to drop below 20.3 Torr was 18, 44 and 81 s at 15%, 22% and 40% oxygen, respectively. There was an inverse correlation between the rate of decline of cortical pO2 and baseline FiO2 levels. With reventilation, the cortical pO2 reached maximal values of 42.8, 51.9 and 57.2 Torr at 15%, 22%, and 40% oxygen, respectively, before returning to the pre-apnea values. The present results show that apnea of less than 30 s duration at an FiO2 of 22% do not result in significant cortical hypoxia in hemodynamically stable piglets. Increasing the FiO2 to above 22% may possibly increase the rate of recovery of tissue oxygenation but it also may facilitate post-hypoxic cortical hyperoxia, a factor that may predispose the immature brain to free radical injury.

Peritoneal dialysis-related peritonitis treatment recommendations: 1996 update

The recommendations provided in this document represent a distillation of various experiences, as well as data obtained from published studies in the setting of substantial changes in antibiotic sensitivity. It is hoped that this revised compilation will provide a basis upon which future developments and advances can be made in the therapeutic approach to infectious complications of peritoneal dialysis.

Differences in factors influencing the familial aggregation of febrile convulsion in population and hospital patients

Socio-demographic data, initial clinical manifestations, outcome and family aggregation of febrile convulsion (FC) were compared between 85 population and 364 multicenter patients. More patients presented with clustering of seizures and had recurrence of FC in multicenter group than in population group. Multicenter patients had more fever episodes per year, more day-card attendance and a higher incidence of FC history in their parents. The odds ratio of FC in the siblings was 6:1 in population group and 12:1 in multicenter group. Lower socioeconomic status influenced the presence of FC in the sibling of population group. Instead, FC histories in the father and paternal cousins of probands had influence on the presence of FC in the siblings of multicenter group. We conclude that the population FC sample rather than the hospital sample is the more representative. And there are differences not only in the clinical manifestations but also in the effect of environmental and genetic influences on the family aggregation in population and hospital patients.

L-deprenyl (selegiline) decreases excitatory synaptic transmission in the rat hippocampus via a dopaminergic mechanism

The effect of L-deprenyl (selegiline) on the excitatory synaptic transmission was characterized in the CA1 neurons of rat hippocampal slices by using a intracellular recording technique. Superfusion of L-deprenyl (0.1-10 microM) reversibly decreased the EPSP, which was evoked by orthodromic stimulation of the Schaffer collateral-commissural afferent pathway in a concentration-dependent manner. The sensitivity of postsynaptic neurons to the glutamate receptor agonists, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid or N-methyl-D-aspartate, was not affected by L-deprenyl (1 microM) pretreatment. In addition, L-deprenyl (1 microM) clearly increased the magnitude of paired-pulse facilitation regardless of the interstimulus intervals of 20 to 300 msec used. The ability of L-deprenyl to decrease the EPSP amplitude was not observed in the dopamine-depleted rats. Pargyline and 4-phenylpyridine, the monoamine oxidase type B inhibitors, mimicked the depressant effect of L-deprenyl on the EPSP. Moreover, the reduction of L-deprenyl (1 microM) on the EPSP amplitude was specifically antagonized by sulpiride (0.01-0.1 microM), a selective dopamine D2 receptor antagonist. However, the dopamine D1 receptor antagonist, SKF-83566 (1-10 microM), did not significantly affect L-deprenyl's action. These results indicate that the monoamine oxidase type B inhibitory ability leading to an increase of the dopaminergic tonus in the hippocampus is involved in the L-deprenyl-induced depression of excitatory synaptic transmission in the CA1 region of the rat hippocampus. Moreover, application of L-deprenyl (1 and 10 microM) also reversibly suppressed the epileptiform activity evoked by picrotoxin.

Presynaptic inhibition of excitatory neurotransmission by lamotrigine in the rat amygdalar neurons

Lamotrigine (LAG) is a new antiepileptic drug which is licensed as adjunctive therapy for partial and secondary generalized seizures. In the present study, the mechanisms responsible for its antiepileptic effect were studied in rat amygdaloid slices using intracellular recording and whole-cell patch clamp techniques. Bath application of LAG (50 microM) reversibly suppressed the excitatory postsynaptic potentials (EPSPs) and currents (EPSCs) evoked by stimulating ventral endopyriform nucleus. Synaptic response mediated by the N-methyl-D-aspartate (NMDA) receptor (EPSPNMDA) was isolated pharmacologically by application of a solution containing non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX,10 microM) and gamma-aminobutyric acidA receptor antagonist bicuculline (20 microM). LAG produced a parallel inhibition of EPSPNMDA. Postsynaptic depolarization induced by alpha-amino-5-methyl-4-isoxazole propionate (AMPA) was not altered by LAG. In addition, LAG increased the ratio of the second pulse response to the first pulse response (P2/P1), which is consistent with a presynaptic mode of action. The L-type Ca+2 channel blocker nifedipine (20 microM) had no effect on LAG-induced presynaptic inhibition. However, the depressant effect of LAG was markedly reduced in slices pretreated with N-type Ca+2 channel blocker omega-conotoxin-GVIA (omega-CgTX-GVIA, 1 microM) or a broad spectrum Ca+2 channel blocker omega-conotoxin-MVIIC (omega-CgTX-MVIIC, 1 microM). It is concluded that a reduction in omega-CgTX-GVIA-sensitive Ca+2 currents largely contributes to LAG-induced presynaptic inhibition.

Middle ear catalase distribution in an animal model of otitis media

Increasing evidence implicates free radicals in the pathogenesis of inflammatory disease, including otitis media. The anti-oxidant enzymes catalase, glutathione peroxidase and superoxide dismutase protect tissues from the destructive effects of free radicals. Our previous work has shown depressed levels of superoxide dismutase in the infected middle ears of a guinea pig model of otitis media in comparison with normal control ears. We studied the distribution and relative abundance of catalase in the middle ear of this animal model in an effort to elucidate the role free radicals play in the pathogenesis of otitis media. Catalase distribution was mapped immunohistochemically in the middle ears of guinea pigs with induced streptococcus otitis media, and compared with normal control ears. In the control ears, catalase was localized to the epithelium of the middle ear mucosa, with scant distribution in the submucosa. The infected ears demonstrated inflammatory cell invasion with hyperemia and submucosal edema. Catalase was localized to the epithelium and had scant distribution in the submucosa. This distribution was similar to that found previously with superoxide dismutase. Enzyme-linked immunosorbent assay of catalase demonstrated a mean value of 1.00 +/- 0.06 microgram/mg protein in the control ears, and 1.06 +/- 0.12 microgram/mg in the infected ears, but these two values were not statistically different.

Severe myoclonic epilepsy in infancy: evolution of electroencephalographic and clinical features

Since 1987, we have diagnosed 10 patients, 4 males and 6 females, aged 2-11 years at the last evaluation, who all met the following criteria of severe myoclonic epilepsy in infancy (SMEI): generalized or unilateral long-lasting febrile clonic seizures in the first year of life; the subsequent appearance of myoclonic seizures and other types of seizure (partial seizures, atypical absences and convulsive status epilepticus); and neuropsychological deterioration for a certain period. Family histories of epilepsy and febrile seizures could be traced in 1 and 3 cases, respectively. None of them had previous personal history of brain insult. Electroencephalographic (EEGic) recordings in febrile seizure stage were normal; and continuous prophylaxis with phenobarbital failed to prevent the recurrence of febrile seizures. EEG studies in myoclonic stage showed generalized spike-and-waves, polyspike-and-waves, focal abnormalities and/or photosensitivity. The seizures were highly resistant to antiepileptic drugs. Our experiences suggested that comedication of valproic acid, clonazepam and carbamazepine may be most effective in treatment of the diverse seizures including myoclonic seizures, myoclonic-tonic-clonic seizures, atypical absences and partial seizures. Myoclonic seizures and atypical absences diminished in parallel to a clear-cut decrease in generalized abnormalities on EEG in 4 cases aged more than 7 years. However, the partial seizures, secondarily generalized seizures and status epilepticus were still present. Further investigations should aim to identify the underlying etiology and to search more effective treatment.

Intravenous immunoglobulin therapy in POEMS syndrome: a case report

One course of intravenous immunoglobulin was tried on a patient with the syndrome of polyneuropathy, organomegaly, endocrinopathy, M-protein and skin lesions and Castleman's disease. No effect was noted.

Involvement of the alpha subunit of farnesyl-protein transferase in substrate recognition

Using photoaffinity labeling, we have identified a region in mammalian farnesyl-protein transferase (FPTase) involved in substrate recognition. The photolabel used (Compound 1) is a peptide containing the photoactive amino acid p-benzoylphenylalanine (Bpa). Upon exposure to UV light. Compound 1 inhibits FPTase activity in a time- and concentration-dependent manner. Photoinhibition of FPTase activity by Compound 1 is prevented by adding H-Ras to the reaction mixture, indicating that labeling is targeted to the enzyme active site. We used peptide mapping by HPLC, Edman sequencing, and matrix-assisted time-of-flight (MALDI-TOF) mass spectrometry to identify the site of interaction with radiolabeled Compound 1. These experiments indicate that a specific region of the alpha subunit of the enzyme, Asp110-Arg112, is involved in substrate binding and suggest that Glu111 is likely to be the residue covalently modified by the photoaffinity label. Sequence alignments between yeast and mammalian FPTases reveal that Glu111 is conserved. The implications of this finding are discussed in light of previous mutagenesis studies on FPTase.

Intentional replantation for iatrogenic perforation of the furcation: a case report

Intentional replantation is an accepted endodontic procedure for treatment of teeth in which conventional surgical endodontic treatment is contraindicated. This article presents a rare case of intentional replantation of a mandibular molar that had severe periodontal destruction resulting from iatrogenic perforation of the furcation. A 17-month follow-up evaluation revealed an asymptomatic and functional tooth with no radiographic signs of pathosis. The favorable results obtained might be attributed to the preservation of the vitality of the periodontal ligament; the absence of damaging pressure during extraction; the minimal extraoral treatment time; the use of nonrigid splinting; and the immediate repair of the perforation during a one-visit endodontic procedure. The results obtained with this tooth may indicate the possibility of a successful surgical technique for this otherwise hopeless complication of endodontic therapy.

Mutual inhibitory effects between dopamine and carbachol on the excitatory synaptic transmission in the rat neostriatum

The interactions between dopamine and carbachol on the excitatory synaptic transmission were studied in rat neostriatal slices using an intracellular recording method. Excitatory postsynaptic potentials (EPSPs) were evoked by cortical stimulation. Application of dopamine (DA; 0.1 microM) or carbachol (0.1 microM) produced a dramatic and reversible inhibition of the EPSP amplitude. The inhibitory effect induced by carbachol was markedly attenuated in the presence of either DA (0.1 microM) or the selective D2 dopaminergic receptor agonist (+/-)-2-(N-phenylethyl-N-propyl) amino-5-hydroxytertralin (PPHT; 0.1 microM), but not by the D1 dopaminergic receptor agonist (+/-)-7, 8-dihydroxy-3-allyl-1-phenyl-2, 3, 4, 5-tetrahydro-1H-3-benzazepine (SKF-38393; 0.1 microM) or the D3 dopaminergic receptor agonist R(-)-(4aS, 10bS)-3, 4, 4a, 10b-tetrahydro-4-propyl-2H, 5H-[1] benzogyrano-[4,3-b]-1, 4-oxazin-9-ol (PD-128,907; 0.1 microM). Conversely, muscarinic receptor activation with carbachol (0.1 microM) also completely abolished the DA-induced depression of the EPSP amplitude. In addition, the inhibitory effect of DA on the carbachol-induced depression of the EPSP amplitude was antagonized by sulpiride (1 microM), a selective D2 dopaminergic receptor antagonist. However, D1 dopaminergic receptor antagonist (+/-)-7-bromo-8-hydroxy-3-methyl-1-phenyl-2, 3, 4, 5-tetrahydro-3-benzazepine (SKF-83566; 1 microM) did not affect DA's inhibition. Rp-adenosine-3',5'-cyclic monophosphothioate (Rp-cAMPS; 25 microM), a potent inhibitor of cAMP-dependent protein kinase A (PKA), alone decreased the amplitude of EPSP below baseline values and mimicked the inhibitory effect of DA on the carbachol-induced depression of the EPSP amplitude. Based on these findings, we conclude that the inhibitory effects of D2 dopaminergic receptor and muscarinic receptor activation on the excitatory synaptic transmission in the neostriatum are non-additive and therefore are antagonistic interactions. furthermore, the effect of muscarinic receptor stimulation will depend on the extent of D2 dopaminergic receptor activation and the modulation of the cellular PKA-dependent messenger system seems to contribute to their interactions.

TXA2 agonists inhibit high-voltage-activated calcium channels in rat hippocampal CA1 neurons

Whole cell voltage clamp recordings were used to investigate the effects of thromboxane A2 (TXA2) agonists on the voltage-dependent Ca2+ currents in rat hippocampal CA1 neurons. TXA2 agonists [1S-[1 alpha, 2 beta(5Z), 3 alpha(1E, 3S*)4 alpha ]]-7-[3-[3-hydroxy-4-(4'-iodophenoxy)-1-butenyl]-7-oxabicyclo [2,2,1]heptan-2-yl]-5-heptenoic acid (I-BOP) and U-46619, reversibly suppressed the whole cell Ca2+ currents in a concentration-dependent manner. The effect was blocked by specific TXA2 receptor antagonist, SQ-29548. I-BOP as well as U-46619 inhibited both omega-conotoxin GVIA (CgTx)-sensitive and nimodipine sensitive Ca2+ currents but had no effect on CgTx/nimodipine insensitive Ca2+ currents. The I-BOP and U-46619 inhibition of Ca2+ currents was blocked by internal dialysis of hippocampal neurons with specific protein kinase C (PKC) inhibitors, NPC-15437 and PKC inhibitor-(19-36). Pretreatment of hippocampal neurons with either 5 micrograms/ml pertussis toxin (PTX) or 5 micrograms/ml cholera toxin (CTX) did not significantly affect the suppression of the Ca2+ currents by I-BOP and U-46619. Dialyzing with 1 mM guanosine 5'-O-(3-thiotriphosphate) or 1 mM GDP significantly attenuated the I-BOP or U-46619 action. These results demonstrate that TXA2 agonists inhibit both CgTx- and nimodipine-sensitive Ca2+ currents but not CgTx/nimodipine-insensitive currents in rat hippocampal CA1 neurons via a PTX- and CTX-insensitive G protein-coupled activation of the PKC pathway.

Carbon disulfide induced polyneuropathy: sural nerve pathology, electrophysiology, and clinical correlation

We report the clinical features, electrophysiological studies, sural nerve pathology and recovery course of carbon disulfide-(CS2) induced polyneuropathy in a 48-year-old man who worked in a viscose rayon plant. Sural nerve biopsy 2 years later still showed degeneration of both axon and myelin with a predominant loss of large myelinated fibers and remyelination. Electrophysiologic studies revealed mixed axonal and demyelinating polyneuropathy. To our knowledge, this is the first human report of sural nerve pathology in the recovery stage due to CS2 intoxication. After diagnosis, the patient was removed from the toxic environment. In the following three years, he showed part recovery predominantly in motor function compatible with the serial nerve conduction studies. We conclude that CS2 polyneuropathy may partly recover years after cessation of exposure.