A randomized parallel trial of topical aspirin-moisturizer solution vs. oral aspirin for acute herpetic neuralgia

BACKGROUND

In this study, the efficacy of oral aspirin vs. topical aspirin in moisturizer (Vaseline Intensive Care Lotion) was studied in an open, randomized, parallel trial in patients with acute herpetic neuralgia.

METHODS

Thirty patients were evaluated in the trial, with 15 in each group. The patients were randomized to receive either oral aspirin, 375-750 mg three times a day, or 75 mg topical aspirin/mL of moisturizer (5-10 mL, depending on the extent of involvement), three times a day, for 21 days. Pain was assessed daily by means of a self-rating visual analog scale and physician assessment. In addition, the skin and plasma levels of aspirin were measured in both groups.

RESULTS

The mean time to onset of pain relief was 44 min with topical aspirin and 110 min with oral aspirin. The mean duration of pain relief after a single application of topical aspirin was 5.4 h, whereas it was 3.5 h with oral aspirin. The mean visual analog scale scores for pain with oral aspirin decreased from 68.2 +/- 6.1 on day zero to 43.1 +/- 8.7 on day 21, which was not significant compared with the baseline score. With topical aspirin, the baseline pain score was 77.5 +/- 3.7 and decreased to 6.8 +/- 3 on day 21 (P < 0.001 compared to the baseline score and compared to oral aspirin). The mean plasma and skin levels of aspirin following oral administration were 16.21 +/- 1.1 microg/mL and 1.97 +/- 0.3 microg/mm2, respectively. After topical administration, the mean plasma level of aspirin was 2.29 +/- 0.5 microg/mL (P < 0.01 vs. oral aspirin) and the skin level was 5.96 +/- 0.4 microg/mm2 (P < 0.05 vs. oral aspirin). Treatment tolerance was excellent in both groups.

CONCLUSIONS

This trial has demonstrated that topical aspirin in moisturizer is clearly superior to oral aspirin in relieving the pain of acute herpetic neuralgia, and that the analgesic activity of aspirin is largely due to its local effect.

Anticonvulsant activity of omeprazole in rats

Omeprazole has long been used as an effective agent to treat peptic ulcer. Recent studies have shown that in addition to inhibiting the H(+)-K(+)ATPase, it also inhibits carbonic anhydrase (CA) types I, II and IV. This led us to investigate its anticonvulsant effect in a rat model of electroconvulsion. Since other carbonic anhydrase inhibitors like acetazolamide induce tolerance upon repeated use, we tested the tolerance potential of omeprazole upon repeated administration of up to 1 week. The animals were divided into four groups receiving normal saline, omeprazole 0.5, 1 or 2 mg/kg intraperitoneally. CC(50), i.e. the threshold current inducing tonic hind limb extension in 50% of the rats was established using a technoconvulsometer which delivers currents of varying intensity via ear clip electrodes. The CC(50) was established 30 min after injection of omeprazole. In another group of rats, omeprazole 2 mg/kg was given for 6 days and the CC(50) determined on days 0, 1, 3 and 6. Also the concentration of omeprazole in the brain was determined using high performance liquid chromatography. The CC(50) in vehicle-treated rats was 98 mA, which increased to 126, 135 and 162 mA with 0.5, 1 and 2 mg/kg of omeprazole, respectively. On repeat-dose studies the CC(50) on day 0 was 96 mA, on day 1 166 mA, on day 3 129 mA and on day 6 102 mA. The average brain concentration of omeprazole was 53.2+/-6.9 ng/g of brain tissue. In conclusion, this study has shown omeprazole to be an effective anticonvulsant, but rapidly develops tolerance to its anticonvulsant action. This study can stimulate interest in the development of agents with dual function -- inhibition of CA as well as the accompanying Na(+)-K(+) ATPase -- and such agents may prove to be effective anticonvulsants without exhibiting tolerance.

Lipoatrophic diabetes and end-stage liver disease secondary to nonalcoholic steatohepatitis with recurrence after liver transplantation

BACKGROUND

Lipoatrophic diabetes is an insulin resistance syndrome characterized by the complete or partial lack of adipose tissue and disturbances in lipid and glucose metabolism. Nonalcoholic steatohepatitis (NASH) is a well-described change in liver pathology consisting of steatosis, hepatitis, and fibrosis that can be associated with lipoatrophic diabetes.

RESULTS

This article describes the first reported case of lipoatrophic diabetes with NASH leading to liver failure and liver transplantation. Before transplantation, the patient required 600-700 U of insulin/day. After transplantation, a dramatic decline in her insulin requirements was observed, despite corticosteroids. Eighteen months after transplantation, her glycemic control worsened, and she developed recurrent NASH on serial liver biopsies.

CONCLUSIONS

NASH associated with lipoatrophic diabetes can recur after liver transplantation, and in this case, was accompanied by increased insulin requirements. These results suggest that the development of NASH itself may contribute to the insulin resistance observed in lipoatrophic diabetes.

An audit of the use of antirheumatic drugs in a north Indian referral hospital

OBJECTIVE

This study was conducted with the aim of auditing the pattern of use of antirheumatic drugs in a tertiary care hospital in Northern India.

METHODS

The study was carried out in 1000 patients recruited sequentially from the clinic for a period of 1 year (January to December 1999). Patient data such as age, sex, income, family size, diagnosis, duration of illness, drugs prescribed/duration, adverse drug reaction were noted and used to calculate core drug use indicators and pattern of drug use.

RESULTS

The pattern of drug use was in accordance with the standard practices followed internationally. In rheumatoid arthritis the most common prescriptions were for non-steroidal antiinflammatory drugs (NSAIDs) alone, followed by the combination of NSAIDs, disease modifying agents (DMARDs) and steroids. Of the NSAIDs diclofenac was the most frequently prescribed drug, while chloroquine was the most commonly used DMARD. The most commonly seen adverse drug reactions were gastritis, Cushings syndrome and decreased visual acuity.

CONCLUSION

In conclusion, this study has demonstrated that in this clinic, the pattern of use of antirheumatic drugs follows standard guidelines.

Retrospective dosimetry based on cytogenetic study of individuals chronically exposed to ionizing radiation

Analysis of chromosomal aberrations (CAA) was carried out in 27 radiation workers with cumulative exposures of approximately 500 mSv received over a period of 2-3 decades. A similar study was carried out in 20 age- and gender-matched healthy individuals who served as controls. The average age of the exposed group was 50 years, and that of the controls was 51 years. The absorbed radiation dose was calculated by using the linear component of the in vitro dose response curve established for 60Co gamma-rays. In the controls we found only 3 dicentrics in 5,500 metaphases analyzed. In the exposed group, we detected 49 dicentrics and 1 centric ring in 13,900 metaphases analyzed. Because of the small number of dicentrics scored in each individual, the dose estimates of our method of study suffers from a large statistical uncertainty. The collective dose calculated from our data was 3.4 Sv. The difference in the physical dose based on personal monitoring and that from biological dosimetry may be attributed to the disappearance of lymphocytes carrying the aberrations from the living system. These results are consistent with the present knowledge of the kinetics of turnover of T-lymphocytes. Most residual damage appears to be from the long-lived component of T-lymphocytes with a mean life of 10 years.

Effect of duration of pilocarpine-induced status epilepticus on subsequent cognitive function in rats

The aim of this study was to determine the effect of the duration of pilocarpine-induced status epilepticus (SE) on subsequent cognitive function in rats. SE was induced by pilocarpine (320 mg/kg i.p.) and was terminated by injection of 1 mg/kg diazepam at 30, 60 and 90 min in 3 groups of 10 rats each. Cognitive function was tested by a passive avoidance task and was assessed at the baseline and on days 1, 7, 14 and 21 (post SE). It was found that cognitive function was disrupted on days 7, 14 and 21 post SE in rats who had SE for 60 and 90 min, whereas it was not affected in rats that had 30 min of SE. Hence, the duration of SE may affect future cognitive performance and mandates emergency treatment.

Evidence of functional somatotopy in GPi from results of pallidotomy

The objective of this study was to explore the functional anatomy of the globus pallidus internus (GPi) by studying the effects of unilateral pallidotomy on parkinsonian 'off' signs and levodopa-induced dyskinesias (LID). We found significant positive correlations between the preoperative levodopa responsiveness of motor signs and the levodopa responsiveness of scores in timed tests (Core Assessment Program for Intracerebral Transplantations) in the contralateral limbs and the improvement in these scores after surgery, whereas there was no correlation with the improvement in LID. We also found a highly significant correlation (P: < 0.0001, r = 0.8) between the volume of the ventral lesion in the GPi and the improvement in LID in the contralateral limbs, whereas there was no correlation between the ventral volume and the improvement in parkinsonian 'off' signs. The volumes of the total lesion cylinder and the dorsal lesion did not correlate with the outcome of either dyskinesias or parkinsonian 'off' signs. The differential predictive value of levodopa responsiveness for the outcome of parkinsonian 'off' signs and LID and the different correlations of ventral lesion volume with dyskinesias and parkinsonian 'off' signs indicate that different anatomical or pathophysiological substrates may be responsible for the generation of parkinsonian 'off' signs and dyskinesias. Whereas cells in a wider area of the GPi may be implicated in parkinsonism, the ventral GPi seems to be crucial for the manifestation of LID. We suggest that our observations are additional proof of the functional somatotopy of the systems within the GPi that mediate parkinsonism and dyskinesias, especially along the dorsoventral trajectory used in pallidotomy. The outcome of pallidotomy in which the lesion involves the ventral and dorsal GPi could be the net effect of alteration in the activity of pathways which mediate different symptoms, and hence could be variable.

Anticonvulsant profile of ondansetron in rats

Recent studies have shown the involvement of 5-hydroxytryptamine (5HT) in the pathogenesis of epilepsy. Hence it was decided to investigate the effect of the 5HT3 receptor antagonist ondansetron against maximal electroshock (MES)-induced seizures in rats. Also, the anticonvulsant activity of ondansetron in combination with phenytoin and its effect on the cognitive deficits induced by phenytoin were studied. MES was induced through ear-clip electrodes using a current strength of 150 mA for 0.2 second. The index of protection was taken as the inhibition of tonic hindlimb extension. The ED25 and ED16 doses of ondansetron were combined with subanticonvulsant doses of phenytion, i.e., 6 and 3 mg/kg. The retention latencies in the passive avoidance task (PAT) were assessed on Days 1 and 21 of chronic administration of ondansetron alone, phenytoin alone, and ondansetron in combination with phenytoin. The ED50 of ondansetron was found to be 1.05 (0.51-2.2) mg/kg. The combination of ondansetron with phenytoin had a potentiating effect against MES. Also, the retention latencies in the PAT of ondansetron alone and ondansetron in combination with phenytoin were significantly higher than that of phenytoin alone. Thus, ondansetron has potent anticonvulsant activity in rats and further potentiates the anticonvulsant activity of phenytoin. Also, it attenuates the cognitive dysfunction induced by phenytoin and merits further research for its mechanisms.

Role of nitric oxide in electroshock and pentylenetetrazole seizure threshold in rats

There are contradictory reports on whether nitric oxide (NO) is a proconvulsant or anticonvulsant. Hence a study was designed to investigate the effect of NO donor l-Arginine and NO synthesis inhibitor N omega-nitro-L-arginine (NOARG) on electroshock- and pentylenetetrazole (PTZ)-induced seizure threshold in rats. L-arginine was tested in three doses (75, 150 and 300 mg/kg), and NOARG was administered in doses of 4, 8 and 16 mg/kg. L-Arginine increased the intensity of current required to produce a threshold seizure, whereas NOARG had the opposite effect. In PTZ-induced seizures, L-arginine significantly decreased the dose of PTZ required to produce a threshold seizure, while NOARG increased it. Hence, it was concluded that NO synthase inhibition had the opposite effect in electroshock- and PTZ-induced seizures, meriting further studies on the mechanism of effect.

Role of nitric oxide on insulin induced seizures in mice

The role of nitric oxide (NO) on acute hypoglycemia-induced seizures in mice was investigated using insulin as the hypoglycemic agent. The NO precursor L-arginine in the doses of 150, 500 and 750 mg/kg exhibited a dose-dependent protective effect against seizures induced by 8 mu/kg insulin. The NO synthase inhibitor (L-NMMA) at the doses of 50 and 100 mg/kg potentiated the subconvulsive doses of insulin (2 mu/kg). The onset, duration, number of seizures and the mortality were noted in a 2 hr study period. The results of this study suggest than NO plays an important protective role in acute hypoglycemia induced seizures which are known to occur through the activation of NMDA receptors.

Anticonvulsant and psychomotor activity of nitrendipine alone and in combination with phenytoin and valproate in rats

The effect of nitrendipine (NTP) alone and in combination with phenytoin (PHT) and valproate (VPA) against maximal electroshock seizures (MES) was studied in rats. In addition, the psychomotor effects of NTP alone and in combination with PHT and VPA were evaluated using the following tests: a) rotarod performance; b) spontaneous motor activity; c) despair behavior; d) righting reflex; e) hole board test; and f) passive avoidance test. ED50 values of PHT, VPA and NTP were 13,255 and 3.6 mg/kg, respectively. When NTP was combined with PHT or VPA, the ED50 values decreased to 0.9 and 226 mg/kg, respectively. In the psychomotor function tests, for the same degree of protection (50%) afforded against MES, PHT or VPA produced a greater impairment in all the parameters compared to NTP alone or a combination of NTP with PHT or VPA. Furthermore, NTP reversed the depression and long-term memory loss induced by PHT and VPA. Thus, NTP was effective against MES in rats, potentiating the anti-electroshock activity of PHT and VPA and producing less impairment of psychomotor activity. Thus, the agent can be considered a potential antiepileptic warranting further studies.

Cognitive dysfunction induced by phenytoin and valproate in rats: effect of nitric oxide

Phenytoin (PHT) and Valproate (VPA) are known to induce cognitive dysfunction, in terms of long term memory loss. Nitric oxide (NO) on the other hand is said to help in long term potentiation and hence enhance memory. The effects of nitric oxide donor L-arginine (L-Arg) and nitric oxide synthase inhibitor N-W-L-Nitroarginine (L-NOARG) were studied on the cognitive dysfunction, induced by PHT and VPA in normal healthy rats, using the step-through passive avoidance test (PAT). It was observed that combining L-Arg with PHT significantly enhanced long term memory while, combining PHT with L-NOARG decreased it, as compared to PHT alone. When combined with VPA, L-Arg and L-NOARG increased the retention latency as compared to PVA alone but this was not statistically significant. We conclude that the No donor L-Arg is able to increase the difference in LTE in acquisition and retention trials with both PHT and VPA, but with VPA the increase is not statistically significant.

Cytogenetic analysis of peripheral blood lymphocytes of occupational workers exposed to low levels of ionising radiation

The incidence of chromosomal aberrations was analysed in peripheral blood lymphocytes of occupationally exposed people having cumulative doses of 500 mSv. The exposed individuals showed higher frequencies of dicentrics as well as acentrics than normal controls. Absorbed radiation dose was calculated by using in vitro dose response curve established for Cobalt-60 gamma rays. In the control constituting 17 healthy individuals, two dicentrics were detected among 3700 metaphases analysed. In the exposed group 27 dicentrics and one centric ring was detected among 8400 metaphases analysed. Due to small number of dicentrics scored in each individual, the dose estimate suffers from a large statistical uncertainty. The collective dose was found to be 1.89 Gy. This is in good agreement with the corrected physical doses, assuming a mean life of 10 years for the disappearance of lymphocytes. The physical doses accumulated during the last 10 years of occupation were also in good agreement with the biological dose estimate.

Anticonvulsant profile of nimodipine and nitrendipine against pentylenetetrazole induced seizures in rats

The activity of nimodipine and nitrendipine against pentylenetetrazole (PTZ) induced seizures in Albino rats was studied alone and in combination with valproate. The median effective dose [ED50] of valproate, nimodipine and nitrendipine were initially determined. All the 3 drugs were injected i.p. 30 min before the induction of seizures. Seizures were induced by PTZ 85 mg/kg i.p., and subsequently the effect of combining ED50 doses of nimodipine and nitrendipine with ED50 dose of valproate was evaluated. ED50 of valproate and nitrendipine were 129 and 2.5 mg/kg respectively. ED50 of nimodipine could not be established since a dose-response relationship was not obtained. Hence, for the purpose of combination studies, 4 mg/kg of nimodipine was used. Both nimodipine (4 mg/kg) and nitrendipine (2.5 mg/kg) decreased the ED50 of valproate from 129 to 40 mg/kg. Both nimodipine and nitrendipine potentiate the activity of valproate against PTZ induced seizures and can be considered as potential adjuvant anticonvulsants which merit further study.

Radiotelemetric versus externalized catheter monitoring of blood pressure: effect of vasopressin in spontaneous hypertension

The changes in arterial pressure that follow withdrawal of a 3-h intravenous infusion of arginine vasopressin (AVP; 20 ng/kg/min) in spontaneously hypertensive rats (SHR) were monitored by radiotelemetry or conventional externalized femoral arterial catheters connected to pressure transducers. Baseline control arterial pressure was lower in the telemetry group compared to the externalized group. After withdrawal of the AVP infusion, blood pressure fell below preinfusion levels in both groups but the decrease was much less in the telemetry group. Strikingly, absolute blood pressure values recorded both during and after the vasopressin infusion were remarkably similar in the two groups. Responses in rats with externalized catheters implanted 7 days before infusion of AVP, a protocol similar to the telemetry group, were similar to those in rats with catheters implanted 24 h earlier. Blood pressure remained decreased in SHR infused with AVP for several days with complete recovery requiring 6-7 days. In contrast, physical activity decreased only on the first day following withdrawal of the infusion. Thus, the mechanism accounting for the blood pressure decrease must be of a long duration and unrelated to a change in gross physical activity. The results emphasize the value of radiotelemetry for recording blood pressure responses.

Effect of nimodipine on the efficacy of commonly used antiepileptic drugs in rats

Effect of nimodipine was studied alone and in combination with phenytoin and valproate in maximal electroshock seizures in rats. The test drug was injected i.p. and seizures elicited by a 60 Hz alternating current of 150 mA intensity for 0.25 sec duration through corneal electrodes. The median effective dose (ED50) of phenytoin, valproate and nimodipine were found to be 13, 255 and 4 mg/kg respectively. Addition of ED50 of nimodipine to ED50 of phenytoin and valproate produced an additive effect. Addition of ED25 of nimodipine to ED25 of phenytoin and valproate produced asynergistic effect. Our results show that addition of nimodipine significantly potentiates the anticonvulsant efficacy of phenytoin and valproate.

Effect of nimodipine on the cognitive dysfunction induced by phenytoin and valproate in rats

Anticonvulsant effects of phenytoin (PHT) and valproate (VPA) were studied alone and in combination with nimodipine (NMD) against maximal electroshock (MES)-induced seizures in rats. PHT and VPA induce cognitive deficit in terms of long-term memory loss. The effect of NMD on the cognitive deficit induced by PHT and VPA was studied through the step-through passive avoidance test (PAT). It was seen that there was a potentiation of antielectroshock effect of PHT and VPA when NMD at a dose of 4 mg/kg was combined with PHT or VPA. NMD reversed the long-term memory loss induced by PHT and VPA in the PAT.

Cardiac output mediates the antihypertensive effect of vasopressin in spontaneous hypertension

The contribution of cardiac output and total peripheral resistance to the fall in arterial pressure that follows cessation of a 3-h intravenous infusion of arginine vasopressin (AVP; 20 ng.kg-1.min-1) was studied in conscious spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats instrumented with radiotelemetric probes for recording of blood pressure and ultrasonic transit-time flow probes for measuring cardiac output. Cessation of a 3-h infusion of AVP resulted in a significant decrease in arterial pressure in SHR (14-17 mmHg below preinfusion control levels) but not in WKY or in vehicle-treated controls. The fall in pressure persisted for several days. The fall in pressure was associated with a large decrease in cardiac output of 22 +/- 2 ml/min below control levels in SHR, and the time course of the cardiac output response over several days approximated the time course of the pressure response. By contrast, total peripheral resistance remained elevated for some time on withdrawal of the AVP infusion. We conclude that the withdrawal-induced antihypertensive phenomenon in SHR is mediated by a fall in cardiac output and not by a decline in total peripheral resistance.

Histological and immunological correlates of suspected leprosy lesions

Thirty-two subjects with suspected leprosy lesions were investigated to assess various modalities of sensibility and sweat function and these were correlated with immunological and histological parameters. It was found that pain and temperature, mediated by small unmyelinated fibres were impaired in the early lesions. Impairment of sweat function was seen only when one of the modalities of sensibility was also affected. Antibodies specific to a protein (35 kDa) antigen and phenolic glycolipid 1 of Mycobacterium leprae were positive in nine and 12 cases respectively, while 15 of the 31 biopsies revealed the presence of mycobacterial antigens in these lesions. The implications of these findings are discussed.