Seeking graduation in medical colleges outside India: Is it a 'win-win' or 'lose-lose' situation for the stakeholders and the nation?

The future of Indian students who return as 'foreign medical graduates' (FMG) after training in certain countries is often uncertain. We collected data from newspapers, government resources and agencies involved in handling this issue. We analysed the current status of medical education in India, the Commonwealth of Independent States (CIS) and some neighbouring countries. Of approximately 1.4 million (14 lakh) students taking the National Eligibility cum Entrance Test (NEET), about 5.8% get admission in medical colleges. There are about 554 medical colleges in India with 82 550 MBBS seats, 51.9% seats belong to the government quota. Parents who send their children to a foreign country to do medicine spend ₹1.5 million (15 lakh) tò4 million (40 lakh) against an estimated annual income of ₹1.2 million (12 lakh) and the child spends 4-6 years in a foreign country. Of 38 150 FMGs who took the examinations conducted by the National Board of Examinations from 2015 to 2018, 18.9% passed the FMG examination mandatory for registration to practise medicine in India. The National Medical Commission is trying to solve this issue by removing the age bar for entry to MBBS and recommending lowering of fees for MBBS in government quota. Seeking graduation in medical colleges outside India may not be advisable for those from the middle/ low-income group of India.

Point of care ultrasound training for internal medicine: a Canadian multi-centre learner needs assessment study

BACKGROUND

Significant gaps currently exist in the Canadian internal medicine point-of-care ultrasound (POCUS) curriculum. From a learner's perspective, it remains unknown what key POCUS skills should be prioritized. This needs assessment study seeks to establish educational priorities for POCUS for internal medicine residents at five Canadian residency training programs.

METHODS

All internal medicine trainees [postgraduate year (PGY) 1-5] from five internal medicine residency training programs in Canada (n = 598) were invited to complete an online survey on 15 diagnostic POCUS applications, 9 bedside procedures, and 18 POCUS knowledge items. For POCUS applications and procedures, participants were asked how applicable they are to patient care in internal medicine and the participants' reported skills in those domains. Self-reported knowledge and skills were rated on a 5-point Likert scale, where 1 = very poor and 5 = very good. Applicability was rated, where 1 = not at all applicable and 5 = very applicable.

RESULTS

A total of 253 of 598 residents (42%) participated in our study. Data from one centre (n = 15) was removed because of low response rate (15%) and significant baseline differences between those trainees and the remaining participants. Of the remaining analyzable data from four training programs (n = 238), participants reported highest applicability to internal medicine for the following applications and procedures: identifying ascites/free fluid [mean applicability score of 4.9 ± standard deviation (SD) 0.4]; gross left ventricular function (mean 4.8 ± SD 0.5) and pericardial effusion (mean 4.7 ± SD 0.5); thoracentesis (mean score 4.9 ± SD 0.3), central line insertion (mean 4.9 ± SD 0.3), and paracentesis (mean 4.9 ± SD 0.3), respectively. Overall reported knowledge/skills was low, with skill gaps being the highest for identifying deep vein thrombosis (mean gap 2.7 ± SD 1.1), right ventricular strain (mean 2.7 ± SD 1.1), and gross left ventricular function (mean 2.7 ± SD 1.0).

CONCLUSIONS

Many POCUS applications and procedures were felt to be applicable to the practice of internal medicine. Significant skill gaps exist in the four Canadian training programs included in the study. POCUS curriculum development efforts should target training based on these perceived skill gaps.

Thiamine Prescribing Practices for Adult Patients Admitted to an Internal Medicine Service

BACKGROUND

Thiamine (vitamin B₁) is an essential cofactor responsible for the breakdown of glucose, and its deficiency is associated with Wernicke encephalopathy (WE). There is a lack of evidence from systematic studies on the optimal dosing of thiamine for WE. Objectives: The primary objective was to describe the prescribing patterns for IV thiamine in adult patients admitted to a large teaching hospital. The secondary objective was to evaluate the clinical resolution of WE symptoms (confusion, ataxia, and/or ocular motor abnormalities) in relation to the dose of IV thiamine prescribed.

METHODS

A retrospective design was used to review data for adult patients admitted to an internal medicine service from June 1, 2014, to June 30, 2015. All patients included in the study received IV thiamine: low-dose therapy was defined as 100 mg IV daily and high-dose therapy was defined as dosage greater than 100 mg IV daily.

RESULTS

A total of 141 patients were included; low-dose thiamine was prescribed for 115 (81.6%) and high-dose thiamine for 26 (18.4%). Patients for whom high-dose thiamine was prescribed were more likely to be those in whom a diagnosis of WE was being considered (12/26 [46.2%] versus 5/115 [4.3%], p < 0.001). Of the total 219 IV thiamine doses ordered, 180 (82.2%) were for 100 mg, and 143 (65.3%) were prescribed for once-daily administration. There was no statistically significant difference in the time to resolution of WE symptoms for patients receiving high-dose versus low-dose thiamine.

CONCLUSIONS

A wide variety of thiamine prescribing patterns were noted. This study did not show a difference in time to resolution of WE symptoms in relation to the dose of IV thiamine. Additional large-scale studies are required to determine the optimal dosing of thiamine for WE.

Interaction between Warfarin and Apple Juice

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Validation of the 25-Item Stanford Faculty Development Program Tool on Clinical Teaching Effectiveness

CONSTRUCT: The 25-item Stanford Faculty Development Program Tool on Clinical Teaching Effectiveness assesses clinical teaching effectiveness.

BACKGROUND

Valid and reliable rating of teaching effectiveness is helpful for providing faculty with feedback. The 25-item Stanford Faculty Development Program Tool on Clinical Teaching Effectiveness was intended to evaluate seven dimensions of clinical teaching. Confirmation of the structure of this tool has not been previously performed.

APPROACH

This study sought to validate this tool using a confirmatory factor analysis, testing a 7-factor model and compared its goodness of fit with a modified model. Acceptability of the use of the tool was assessed using a 6-item survey, completed by final year medical students (N = 119 of 156 students; 76%).

RESULTS

The testing of the goodness of fit indicated that the 7-factor model performed poorly, χ(2)(254) = 457.4, p < .001 (root mean square error of approximation [RMSEA] = 0.08, comparative fit index [CFI] = 0.91, non-normed fit index [NNFI] = 0.89). Only standardized root mean square residual (SRMR) indicated acceptable fit (0.06). Further exploratory analysis identified 10 items that cross-loaded on 2 factors. The remainder of the items loaded on factors as originally intended. By removing these 10 items, repeat confirmatory factor analysis on the modified 15-item, 5-factor model demonstrated a better fit than the original model: SRMR = 0.075, NNFI = 0.91, χ(2)(80) = 150.1, p < .001; RMSEA = 0.09; CFI = 0.93. Although 75% of the participants stated they were willing to fill the tool on their preceptors on a biweekly basis, only 25% were willing to do so on a weekly basis.

CONCLUSIONS

Our study failed to confirm factor structure of the 25-item tool. A modified tool with fewer, more conceptually distinct items was best fit by a 5-factor model. Further, the acceptability of use for the 25-item tool may be poor for rotations with a new preceptor weekly. The abbreviated tool may be preferable in that setting.

Measurements of an ablator-gas atomic mix in indirectly driven implosions at the National Ignition Facility

We present the first results from an experimental campaign to measure the atomic ablator-gas mix in the deceleration phase of gas-filled capsule implosions on the National Ignition Facility. Plastic capsules containing CD layers were filled with tritium gas; as the reactants are initially separated, DT fusion yield provides a direct measure of the atomic mix of ablator into the hot spot gas. Capsules were imploded with x rays generated in hohlraums with peak radiation temperatures of ∼294  eV. While the TT fusion reaction probes conditions in the central part (core) of the implosion hot spot, the DT reaction probes a mixed region on the outer part of the hot spot near the ablator-hot-spot interface. Experimental data were used to develop and validate the atomic-mix model used in two-dimensional simulations.

Behavioral rehabilitation of the eye closure reflex in senescent rats using a real-time biosignal acquisition system

In this paper the replacement of a lost learning function of rats through a computer-based real-time recording and feedback system is shown. In an experiment two recording electrodes and one stimulation electrode were implanted in an anesthetized rat. During a classical-conditioning paradigm, which includes tone and airpuff stimulation, biosignals were recorded and the stimulation events detected. A computational model of the cerebellum acquired the association between the stimuli and gave feedback to the brain of the rat using deep brain stimulation in order to close the eyelid of the rat. The study shows that replacement of a lost brain function using a direct bidirectional interface to the brain is realizable and can inspire future research for brain rehabilitation.

The effect of question format and task difficulty on reasoning strategies and diagnostic performance in Internal Medicine residents

BACKGROUND

Previous studies have suggested an association between reasoning strategies and diagnostic success, but the influence on this relationship of variables such as question format and task difficulty, has not been studied. Our objective was to study the association between question format, task difficulty, reasoning strategies and diagnostic success.

METHODS

Study participants were 13 Internal Medicine residents at the University of Calgary. Each was given eight problem-solving questions in four clinical presentations and were randomized to groups that differed only in the question format, such that a question presented as short answer (SA) to the first group was presented as extended matching (EM) to the second group. There were equal numbers of SA/EM questions and straightforward/difficult tasks. Participants performed think-aloud during diagnostic reasoning. Data were analyzed using multiple logistic regression.

RESULTS

Question format was associated with reasoning strategies; hypothetico-deductive reasoning being used more frequently on EM questions and scheme-inductive reasoning on SA questions. For SA question, non-analytic reasoning alone was used more frequently to answer straightforward cases than difficult cases, whereas for EM questions no such association was observed. EM format and straightforward task increased the odds of diagnostic success, whereas hypothetico-deductive reasoning was associated with reduced odds of success.

CONCLUSIONS

Question format and task difficulty both influence diagnostic reasoning strategies and studies that examine the effect of reasoning strategies on diagnostic success should control for these effects. Further studies are needed to investigate the effect of reasoning strategies on performance of different groups of learners.

Sensitivity and specificity of decreased CSF asialotransferrin for eIF2B-related disorder

OBJECTIVE

This is a study estimating diagnostic accuracy of CSF asialotransferrin to transferrin ratio measurement in eIF2B related disorders by using clinical evaluation and EIF2B mutation analysis as the reference standard. eIF2B-related disorder is a relatively common leukodystrophy with broad phenotypic variation that is caused by mutations in any of the five EIF2B genes. There is a need for a simple and clinically valid screening tool for physicians evaluating patients with an unclassified leukodystrophy.

METHODS

CSF two-dimensional gel (2DG) electrophoresis analyses to measure asialotransferrin to transferrin ratios were performed in 60 subjects including 6 patients with documented EIF2B gene mutations, patients with other types of leukodystrophy, and patients with no leukodystrophy.

RESULTS

All six patients with mutation proven eIF2B-related disease showed low to nearly undetectable amounts of asialotransferrin in their CSF when compared to 54 unaffected controls by CSF 2DG analyses in this study. eIF2B-like patients, with clinically similar presentations but no mutations in EIF2B1-5, were distinguished from patients with mutations in EIF2B1-5 by this biomarker. Patients with mutations in EIF2B1-5 had asialotransferrin/transferrin ratio levels significantly different from the group as a whole (p < 0.001). Using 8% asialotransferrin/transferrin ratio as a cutoff, this biomarker has a 100% sensitivity (95% CI = 52-100%) and 94% specificity (95% CI = 84-99%).

CONCLUSION

Decreased asialotransferrin/transferrin ratio in the CSF of patients with eIF2B-related disorder is highly sensitive and specific. This rapid (<48 hours) and inexpensive diagnostic tool for eIF2B-related disorders has the potential to identify patients with likely eIF2B-related disorder for mutation analysis.

A phase I study of MGCD0103 given as a twice weekly oral dose in patients with advanced leukemias or myelodysplastic syndromes (MDS)

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Background: Small molecule inhibitors of histone deacetylase (HDAC) have emerged as novel anticancer agents. MGCD0103 is an oral isotype selective small molecule inhibitor of HDAC. Methods: Eligible patients had relapsed/refractory (RR) AML or MDS (or newly diagnosed disease in patients >60 yrs, ineligible for induction chemotherapy); RR ALL; RR CML. MGCD0103 was administered 2x/weekly for 3 weeks, with no recovery period between cycles. Patients with stable disease or better were eligible to continue therapy indefinitely. Results: Patients have been treated at 4 dose levels: 40, 53, 66 and 83 mg/m2/day, including 19 enrolled patients with the following demographics: M:F = 15:4, median age (range) = 75 (52–83), ECOG 0:1:2 = 5:12:2, diagnosis of RR MDS= 7, RR AML or RR ALL=8: untreated AML or MDS = 4. Cytogenetics (n=12): Diploid = 3, Complex = 4, Del 7 = 3, Del 12 = 1, Del Y = 1. Nineteen patients are evaluable for safety. A total of 38 cycles have been administered with a median of 2 per patient (range, 1–6); 13 patients have completed =2 cycles. One patient experienced grade 3 fatigue at 53 mg/m2 and 2 patients had grade 3 weakness/fatigue at 83 mg/m2 (exceeded the Maximum Tolerated Dose [MTD]) Non-dose-limiting toxicities included lower grade fatigue, diarrhea, and nausea. Plasma PK in 14 patients revealed t 1/2 of 7–12 hr, tmax 0.6- 1 hr, and a dose proportional average Cmax of 155 ng/mL at 40 mg/m2 and 225 ng/mL at 53 mg/m2. Significant inhibition of whole cell total HDAC activity within PBMC was observed in a majority of patients, at all dosing levels. Four patients have experienced stable disease. Conclusions: MGCD0103 has been well-tolerated in patients with advanced leukemias or MDS. MTD has been reached, and the recommended phase II 2x/week dose is being confirmed. At all dose levels, significant HDAC inhibition was observed.

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IL18 and IL18R1 polymorphisms, lung CT and fibrosis: A longitudinal study in coal miners

It has been suggested that interleukin (IL)-18 plays a role in the development of inflammatory and fibrosing lung diseases. Associations of polymorphisms in the genes coding for IL-18 (IL18 /G-656T, C-607A, G-137C, T113G, C127T) and its receptor (IL18R1 /C-69T) with coal workers' pneumoconiosis (CWP) were studied in 200 miners who were examined in 1990, 1994 and 1999. Coal-dust exposure was assessed according to job history and ambient measures. The main health outcome was lung computed tomography (CT) score in 1990. Internal coherence was assessed by studying CT score in 1994, 4-yr change in CT score and CWP incidence and prevalence. CT score in 1990 was a good predictor of radiographic grade in 1999 and, therefore, an appropriate subclinical quantitative trait. The IL18 -137C allele was associated with lower CT score in 1990 and 1994 (1.24 versus 1.69 and 1.57 versus 2.46, respectively), slower progression of CT score between 1990 and 1994 and lower pneumoconiosis prevalence in 1999 relative to the G allele (0.33 versus 0.77 and 8.2 versus 19.6%, respectively). Smoking- or dust-adjustment, and stratification on IL18R1 genotype and adjustment for haplotype effects did not change the conclusions. In conclusion, the results of the present study suggest a role for IL18 in reducing the development of this fibrosing lung disease.

Sharing of the home base: a social test in rats

The open field provides abundant opportunities for a pair of rats to express social interactions. Rats demonstrate social proximity while exploring the open field and also during simultaneous occupancy of a home base (HB). The HB is defined as a place in the field for which rats show a long-term preference, both in terms of occupancy and as a starting and ending point of exploratory excursions. In the present study, the social proximity of pairs of rats treated with phencyclidine (PCP; 2 mg/kg) or saline (Sal), and rats treated with clozapine (CLZ; 1.3 mg/kg) alone or in combination with PCP (CLZ-PCP), was videotaped and analysed algorithmically. PCP was tested for its disruptive effects on social interactions, and CLZ was tested for its ability to reverse some forms of the disruptive effects of PCP. The results showed that PCP reduced the rate of pairs establishing a common HB and shortened social HB occupancy, but had no effect on episodes of social exploration in the field. These findings demonstrate that the antisocial effect of PCP cannot be generalized across the entire spectrum of behavioural states in the open field. CLZ further decreased rather than increased social HB occupancy. This effect was derived from the reduction in rate of pairs establishing a common HB.

Effect of TNF and LTA polymorphisms on biological markers of response to oxidative stimuli in coal miners: a model of gene-environment interaction. Tumour necrosis factor and lymphotoxin alpha

INTRODUCTION

Interaction between genetic background and oxidative environmental stimuli in the pathogenesis of human lung disease has been largely unexplored.

METHODS

A prospective epidemiological study was undertaken in 253 coal miners. Intermediate quantitative phenotypes of response to oxidant exposure, including erythrocyte glutathione peroxidase (GSH-Px) and catalase activities, were studied. Oxidant exposures studied were smoking habits and cumulative dust exposure assessed by job history and ambient measures. Disease phenotypes included subclinical computed tomography score at the first survey and x ray profusion grades twice, five years apart, to assess established coal workers' pneumoconiosis (CWP). Miners were genotyped for common functional polymorphisms in the gene for tumour necrosis factor alpha (TNF) and lymphotoxin alpha (LTA), two proinflammatory cytokines that have been implicated in the pathogenesis of chronic lung diseases.

RESULTS

Regarding gene-environment interaction on intermediate phenotypes, results showed interaction of a promoter polymorphism at the -308 position in TNF with occupational exposure on erythrocyte GSH-Px activity with a significant association in those with high exposure (p=0.003), whereas no association was observed among those with low exposure (interaction p=0.06). Regarding gene intermediate phenotype interaction on clinical outcome, results showed an association of CWP prevalence with an NcoI polymorphism in LTA in those with low catalase activity (p=0.05), whereas no association was observed in those with high activity (interaction p=0.03). No other significant association was observed.

CONCLUSION

The results suggest that interactions of genetic background with environmental exposure and intermediate response phenotypes are important components in the pathogenesis of CWP.

Social attraction between rats in open field: long-term consequences of kindled seizures

Kindling of the amygdaloid complex in rats results in an enhanced emotionality frequently expressed by an elevated anxiety and defensive attitude toward other animals. Defensive attitude may have important consequences in social context and if tested in a large space it may eventually lead to social withdrawal. To test this hypothesis, rats were subjected to daily kindling sessions and their behavior was compared to implanted-sham and intact rats. Blood was collected after selected kindling trials for assessment of corticosterone response. Behavioral tests started 1 month after the last kindling trial and consisted of two open field sessions. A solitary rat was tested in the 1st session and pair of rats was tested simultaneously in the second session. Results showed that kindling changed the balance between exploration and occupation of a home base (HB) in the open field, in favor of higher preference of the home base occupancy. These results were apparent only during the social session leading to the conclusion that rats preferred to stay in the home base to maximize the proximity to a partner rat. This was supported by the observation that by increasing the occupancy of the HB, the kindled rats accomplished the longest concurrent presence with the partner rat in the common HB. We discuss the level of inter-rats aggression as a factor defining whether the anxious kindled rats will respond with increased or decreased social attraction in the open field test.

Two-stage theory of conditioning: involvement of the cerebellum and the amygdala

Classical conditioning is thought to proceed through two successive stages: fast rate emotional conditioning followed by slower motor conditioning. To verify the involvement of the amygdala and the cerebellum in these two stages of learning, rats were subjected to paired tone-airpuff (CS-US) trials. Lick suppression to CS was used as an index of conditioned emotional response (emotional CRs) and head movement was used as an index of motor CRs. The results showed that the fast acquisition of emotional CRs was dependent on the integrity of the amygdala and the slow acquisition of motor CRs was dependent on the integrity of the cerebellar interpositus nucleus. Cerebellar lesions had no effect on the acquisition of the emotional CRs but prevented the extinction of the emotional CRs seen in intact rats after massive conditioning. These findings suggest that the amygdala and the cerebellum provide the neuronal substrates of the fast and slow conditioning systems, respectively, and that conditioning-related cerebellar output interacts with the amygdala-based emotional conditioning.

Involvement of the amygdala in classical conditioning of eyeblink response in the rat

The two-factor theory postulates that classical conditioning proceeds through two stages, which support successive acquisition of emotional and motor responses. Emotional conditioning is thought to facilitate the subsequent acquisition of the motor response. This form of interaction between the two stages of learning can be investigated while considering the central role of the amygdala and the cerebellum in emotional and motor conditioning, respectively. Rats with bilateral lesions of the amygdala or the cerebellar interpositus or intact rats were subjected to a fear conditioning session followed by four eyeblink conditioning sessions. Another group of intact rats was subjected to eyeblink conditioning only. The CS in the fear conditioning session was a 73 dB tone, paired with a 100 dB noise-US. The same CS was paired with a periorbital electroshock-US during eyeblink conditioning. Results showed that fear preconditioning facilitated the subsequent eyeblink conditioning among the intact groups. Amygdaloid lesions abolished this facilitatory effect of fear conditioning. These findings demonstrate that amygdala-mediated emotional conditioning facilitates the subsequent acquisition of cerebellum-mediated motor responses.

Phytonadione therapy in a multiple-drug overdose involving warfarin

We cared for a patient who ingested an unknown amount of acetaminophen with zopiclone and warfarin. The only liver function test that was abnormal was an increased international normalized ratio (INR), which remained elevated despite treatment with subcutaneous phytonadione and a prolonged infusion of N-acetylcysteine. An interaction between acetaminophen and warfarin may have decreased the hepatic metabolism of warfarin. The patient received numerous antibiotics that may have contributed to the increased INR. The prolonged elevation of INR also may have been due to infrequent administration of phytonadione.

The expression of the calcium binding protein calretinin in the rat striatum: effects of dopamine depletion and L-DOPA treatment

The activity of the striatum is regulated by glutamate and dopamine neurotransmission. Consequent to striatal dopamine depletion the corticostriatal excitatory input is increased, which in turn can raise intracellular calcium levels. We investigated changes in the neuronal expression of the calcium binding protein calretinin related to dopamine depletion and l-DOPA administration. Immunohistochemical methods were used to assess calretinin in the striatum of rats with unilateral lesions of the nigrostriatal system. In these animals we observed a loss of the patchy distribution of calretinin fibers. Moreover, after dopaminergic depletion we detected two new, not previously described, calretinin cell types, the presence of which could be related to morphological changes induced by loss of a dopaminergic input. We also found an increase in the number of calretinin-labeled cells in the striatum ipsilateral to the lesion compared to the contralateral striatum or to the striatum of normal rats. This increase was mostly evident at 3 weeks postlesion and tended to decrease toward normal levels at 6, 10, and 18 weeks postlesion. In unlesioned animals, l-DOPA administration did not induce changes in the expression of calretinin. In unilaterally lesioned animals, l-DOPA reversed the increase in the number of calretinin-positive cells induced by the lesion. However, chronic l-DOPA administration was less effective than acute l-DOPA in reversing the effect of the lesion. The present data suggests that striatal calretinin neurons are sensitive to dopamine depletion. Increased expression of calretinin in striatal cells may be consequent to enhanced striatal excitatory input.

Clinical features and treatment interventions for human immunodeficiency virus-associated neurologic disease in children

HIV-1 infection in children and adolescents can cause progressive neurologic disease, affective brain growth, motor function, and neurodevelopment. In addition, myelopathies, neuropathies, myopathies, strokes, and psychiatric or behavioral manifestations can be a result of HIV-1 infection, OI, or toxicities of treatment interventions. CNS OI are important causes of morbidity and mortality, often mimicking the HIV-1 associated neurologic syndromes. Psychometric, clinical, neuroradiologic, and laboratory testing are valuable for diagnostic and treatment decisions. The cornerstone of treating HIV-1-associated neurologic disease is providing an effective regimen of antiretroviral drugs to reduce the viral burden. It is also necessary to provide rehabilitation, optimize nutrition, supply appropriate antimicrobial prophylaxis against OI, minimize pain, and treat neurobehavioral or psychiatric complications. Efforts at preventing HIV-1 infection are important for diminishing and allaying the growth of this international pandemic.

Neurologic, neurocognitive, and brain growth outcomes in human immunodeficiency virus-infected children receiving different nucleoside antiretroviral regimens. Pediatric AIDS Clinical Trials Group 152 Study Team

OBJECTIVES

To compare the impact of three different nucleoside reverse transcriptase inhibitor regimens, zidovudine (ZDV) monotherapy, didanosine (ddI) monotherapy, and ZDV plus ddI combination therapy, on central nervous system (CNS) outcomes in symptomatic human immunodeficiency virus (HIV)-infected children.

METHODS

Serial neurologic examinations, neurocognitive tests, and brain growth assessments (head circumference measurements and head computed tomography or magnetic resonance imaging studies) were performed in 831 infants and children who participated in a randomized double-blind clinical trial of nucleoside reverse transcriptase inhibitors. The Pediatric AIDS Clinical Trials Group study 152 conducted between 1991 and 1995 enrolled antiretroviral therapy-naive children. Subjects were stratified by age (3 to <30 months of age or 30 months to 18 years of age) and randomized in equal proportions to the three treatment groups.

RESULTS

Combination ZDV and ddI therapy was superior to either ZDV or ddI monotherapy for most of the CNS outcomes evaluated. Treatment differences were observed within both age strata. ZDV monotherapy showed a modest statistically significant improvement in cognitive performance compared with ddI monotherapy during the initial 24 weeks, but for subsequent protection against CNS deterioration no clear difference was observed between the two monotherapy arms.

CONCLUSIONS

Combination therapy with ZDV and ddI was more effective than either of the two monotherapies against CNS manifestations of human immunodeficiency virus disease. The results of this study did not indicate a long-term beneficial effect for ZDV monotherapy compared with ddI monotherapy.

Effects of prenatal exposure to gamma rays on circling and activity behavior in prepubertal and postpubertal rats

The study departs from the finding that postural asymmetries in low-weight female neonates are greatly increased following prenatal lesions inflicted by gamma irradiation at day 15. Given that amphetamine-induced rotation in adult rats could be predicted by their infantile axial asymmetry we expected a greater tendency for circling in rats exposed at day 15. To examine this prediction, Sprague-Dawley rats were exposed to a single dose of gamma radiation at 1.5 Gy with a dose-rate of 0.15 Gy/min. The dose was delivered on one of the embryonic days (E15, 17 or 19) throughout the whole body of pregnant dams. Sham prenatal exposure of controls consisted of placing pregnant rats in the same environment for 10 min. All rats were tested during the active part of the circadian cycle. At postnatal day 27 (P27) exposed pups did not differ in rates of either spontaneous or d-amphetamine-induced circling from the shams. At P57, in keeping with our prediction, E15 rats manifested enhanced rotation and higher net asymmetry. However, E17 also showed higher gyration tendency compared to their shams while exposed E19 rats did not differ from their shams. The role of intrinsic DAergic imbalance presumably sharpened by irradiation at E15 and of neocortical deficit inflicted at E15 and E17 are discussed.

Reevaluation of the striatal role in the expression of turning behavior in the rat model of Parkinson's disease

A traditional view holds the belief that the behavioral effects of l-dihydroxyphenilalanine (l-DOPA) in Parkinsonian patients are achieved through the action of the newly produced dopamine (DA) on striatal DA receptors. In contrast to this view, recent studies in the rat model of Parkinson's disease point to the substantia nigra pars reticulata as an important target for the behavioral effects of l-DOPA. In the present study, we tested the contribution of the substantia nigra vs. that of the striatum, in the expression of contralateral turning induced by l-DOPA in rats with unilateral dopaminergic depletion. Rats turned contralaterally to the lesion in response to either intrastriatal or systemic l-DOPA administration. Injections of lidocaine into the denervated striatum substantially decreased, and occasionally completely abolished, the contralateral turning after systemic l-DOPA. These findings indicate that activation of the DA depleted striatum is both sufficient and essential for the expression of behavioral response after systemic administration of l-DOPA. The contribution of the substantia nigra to this behavioral response seems to depend to a great extent on an active striatal outflow.

Dissociation between startle and prepulse inhibition in rats exposed to gamma radiation at day 15 of embryogeny

The role of prenatal trauma in disordered sensory gating was explored in albino rats of the Sprague-Dawley strain. Pregnant rats were exposed to 1.5 Gy (0.15 Gy/min) of the whole-body gamma radiation on days 15, 17, or 19 of gestation. Controls were sham-exposed during 10 min in the same conditions. Exposed and control offsprings were evaluated for the auditory startle response (ASR) and its gating by either the habituation process or by the preceding weak sensory stimulus in the prepulse inhibition of startle (PPI) procedure. The tests were conducted when the animals reached 27 and 57 days of age. A noticeable hyperresponding and delayed habituation of startle were found in rats exposed at E15, with meager effects in rats exposed at E17 and E19. Maximal deficit was obtained on tests conducted on P57 but not on P27. However, in rats pretreated with amphetamine, dysfunctional startle was unmasked already on the P27 test. By contrast, PPI was insensitive to the damaging effect of prenatal irradiation at either period. This dissociation is reminiscent of one observed in patients with posttraumatic stress disorder (PTSD).

A neuronal and neuroanatomical correlate of HIV-1 encephalopathy relative to HIV-1 encephalitis in HIV-1-infected children

Progressive central nervous system dysfunction analogous to the AIDS dementia complex (ADC) seen in adults (HIV-1-associated progressive encephalopathy or HIV-1 encephalopathy) commonly occurs in HIV-1-infected children. The cause appears to be directly or indirectly related to HIV-1, rather than to other opportunistic pathogens. The exact mechanism(s) by which the virus affects brain function is not known. To determine whether the virus might modify brain function via an alteration in cortical neurons, we examined peptide neurotransmitter expression in the frontal cortex of HIV-1-infected cases with clinical HIV-1 encephalopathy relative to pathologic HIV-1 encephalitis. In situ hybridization was used to determine the level of peptide neurotransmitter expression of somatostatin in the frontal cortex of cases with and without HIV-1 encephalopathy and/or HIV-1 encephalitis. A 2-fold higher number of preprosomatostatin mRNA-positive interneurons was present in layer IV of cases with HIV-1 encephalitis compared with cases without HIV-1 encephalitis. In cases with PE, this neuronal alteration was 4- to 5-fold higher than in cases without PE, and was present in subcortical white matter in addition to layer IV. In cases having both PE and HIV-1 encephalitis, and in cases with HIV-1 encephalitis alone, these neuronal alterations in layer IV and/or subcortical white matter related to disseminated microglial nodules, even when these potentially viral-infected cells were negative for HIV-1 p24 antigen, a marker of productive viral infection. An alteration in preprosomatostatin mRNA-expressing cells occurring with HIV-1 encephalitis may be at least one mechanism that contributes to HIV-1 encephalopathy. When compared with other cortical laminae, layer IV receives most of its synaptic input from the mediodorsal nucleus of the thalamus. Neurons in the subcortical white matter project to the thalamus. The thalamus has been shown to have high amounts of viral antigen and increased metabolic activity in patients with AIDS. An alteration in preprosomatostatin mRNA-expressing cells may play a role in HIV-1 encephalopathy.

Levodopa therapy improves motor function in HIV-infected children with extrapyramidal syndromes

Five children with human immunodeficiency virus type-1 (HIV-1) infection, aged 4 to 13 years, manifested extrapyramidal dysfunction characterized by rigidity/stiffness, ambulation difficulties/shuffling gait, dysarthria/drooling/swallowing dysfunction, hypomimetic/inexpressive facies, and bradykinesia. Levodopa therapy caused an initial improvement in all symptoms, and the effect was sustained in most patients. Levodopa is a useful adjunctive therapy in HIV-1-infected children with extrapyramidal syndromes, by enhancing motor function and improving their quality of life.

Delayed habituation of the skin-conductance orienting response correlates with impaired performance on the Wisconsin Card Sorting Task in schizophrenia

The skin-conductance orienting response (SCOR) in schizophrenia is often characterized by either nonresponding or delayed habituation to repeated nonsignal tones. These abnormalities are poorly related to other dimensions of schizophrenia. In the present study, we confirmed that about 50% of patients with chronic schizophrenia are SCOR nonresponders. Nonresponders, however, did not differ from responders on postmorbid psychiatric or pharmacological course, and we therefore could not confirm the hypothesis that course of illness follows a more marked pattern of increasing severity in nonresponders. Performance on the Wisconsin Card Sorting Test (WCST) was particularly poor in a subgroup of responders who exhibited either delayed habituation and/or dishabituation of SCORs to tones applied after a short rest period. It is possible that pathology of the prefrontal cortex mediates the SCOR abnormalities that characterize schizophrenic patients who perform poorly on the WCST.

Kindled seizures do not affect adenosinergic inhibition of DA or ACh release in rat accumbens or PFC

Epileptic seizures are thought to terminate largely as a result of the extracellular accumulation of the purinergic neuromodulator, adenosine, released by discharging neurons. However, the postictal surge in extracellular adenosine and its widespread inhibitory effects are limited in time to only a few minutes and cannot directly account for increased resistance to seizures and the complex behavioural and motivational effects that may persist for hours or days after a seizure. The present study examined whether kindled seizures might alter the sensitivity or efficacy of inhibitory presynaptic adenosine receptors, and thereby induce more enduring changes in downstream transmitter systems. Rats were kindled in the amygdala of the dominant cerebral hemisphere, contralateral to the preferred direction of rotation, and their brains were removed either 2 h or 28 days after completion of kindling. Inhibition of electrically stimulated release of dopamine (DA) and acetylcholine (ACh) by the A1 adenosine-receptor agonist, R-phenylisopropyladenosine (R-PIA) was then measured in the prefrontal cortex (PFC) and nucleus accumbens. R-PIA (1.0 microM) inhibited [1H]DA release from PFC and nucleus accumbens tissue, and [14C]ACh release from nucleus accumbens tissue, but release was unaffected by prior kindling, regardless of the intervening interval. These results do not support suggestions that DA or ACh might mediate the effects of seizure-induced changes in purinergic inhibitory tone so as to cause long-term shifts in seizure threshold and postictal behavior.

Neurological and developmental problems in pediatric HIV infection

Human immunodeficiency virus type-1 (HIV-1)-associated neurologic disease, known as "HIV-1-associated progressive encephalopathy" (PE), is a common concomitant in the progression towards AIDS. PE, characterized by a triad of symptoms including impaired brain growth, progressive motor dysfunction, and loss or plateau of developmental milestones, is believed to result from both direct and indirect effects of HIV-1 infection on the central nervous system (CNS). Consequent to the hallmark systemic immune deficiency of HIV infection, the CNS becomes susceptible to opportunistic infections which add further morbidity and mortality, and may contribute either directly or indirectly to neurologic symptoms which can often mimic PE. Static encephalopathies (SE) represent fixed, nonprogressive neurologic or neurodevelopmental deficits in HIV-infected children. SE may or may not be caused by HIV infection but are often associated with such identifiable insults as prematurity, in utero exposure to toxins or infectious agents, or head trauma. Additional neurological manifestations of HIV infection are seizures, cerebrovascular complications (i.e., stroke), myelopathies, neuromuscular syndromes, and CNS complications of opportunistic infections. Neurobehavioral aberrations have also been observed in pediatric HIV infection. In addition to the neuropathogenesis, theories regarding the timing and detection of the neurological problems associated with pediatric HIV infection are discussed along with a presentation of current treatment paradigms and their rationales. The importance of identifying the numerous environmental factors, including nutritional status, that may confound the ability to discriminate between a primary or secondary role of HIV infection in the various neurological problems of HIV infection is discussed.

Epidural hematoma of a cauda equina in a child with hemophilia A

PURPOSE

The presenting signs, treatment, and outcome of an epidural hematoma of the cauda equina in a child with severe hemophilia are reported for the first time.

PATIENTS AND METHODS

A 20-month-old boy with severe hemophilia A (factor VIII <0.01 U/ml) presented with a 12-day history of refusal to stand and constipation of 5-7 days duration. He had normal deep tendon reflexes with normal sensation and withdrawal to pinprick of his lower extremities bilaterally. He stood on his right leg, but had inversion of his left foot and refused to bear weight on his left leg. MRI revealed an epidural hematoma of the cauda equina and a distended bladder. Factor VIII replacement therapy and lumbosacral laminectomy with evacuation of the hematoma resulted in recovery of a normal gait, but bladder dysfunction persisted for 11 months. Clean intermittent catheterization (CIC) was required until bladder function returned.

RESULTS

Complete neurologic recovery occurred 11 months after presentation

CONCLUSION

This case demonstrates the following points: (a) an epidural hematoma of the cauda equina in a child with severe hemophilia can present with neurologic findings that are as subtle as those seen in normal children; (b) CIC can be performed safely over an extended period without factor VIII replacement; and (c) complete recovery is possible, despite prolonged bladder dysfunction and a 12-day interval between the onset of symptoms and treatment.

Carnitine in human immunodeficiency virus type 1 infection/acquired immune deficiency syndrome

There is an increasing body of evidence that subgroups of patients infected with human immunodeficiency virus type 1 possess carnitine deficiency. Secondary carnitine deficiencies in these individuals may result from nutritional deficiencies, gastrointestinal disturbances, renal losses, or shifts in metabolic pathways. However, tissue depletion precipitated by drug toxicities, particularly zidovudine, is a major etiology and concern. Carnitine deficiency may impact on energy and lipid metabolism, causing mitochondrial and immune dysfunction. There are convincing laboratory data showing the in vitro ameliorative effects of L-carnitine supplementation of zidovudine-induced myopathies and lymphocyte function. Studies measuring the impact of L-carnitine supplementation on clinical characteristics are ongoing.

Activation of the subthalamic nucleus and pedunculopontine tegmentum: does it affect dopamine levels in the substantia nigra, nucleus accumbens and striatum?

Parkinson's disease is a neurodegenerative disorder, of which the most prominent morphological feature is the progressive loss of dopaminergic nigrostriatal neurons. Increased glutamatergic transmission in the basal ganglia has been implicated in the pathophysiology of Parkinson's disease (PD). This study investigated whether death of substantia nigra (SN) dopaminergic neurons could be caused by the hyperactivity of afferent pathways resulting in the release of a toxic dose of excitatory amino acids in the SN. Twice-daily unilateral stimulation of the subthalamic nucleus (STN) for 21 days, using two different pulse frequencies and current strengths, significantly increased amphetamine-induced rotation, whereas sham stimulated rats showed significantly reduced rotation. Striatal and SN dopamine (DA) levels were unaffected when compared to naïve and sham stimulated rats. However, levels of the DA metabolite, homovanillic acid (HVA), were significantly higher in the ipsilateral anterior striata of rats that had been stimulated at high frequency (100 Hz) and low current (100 microA) as compared to sham treated animals. Stimulation of the pedunculopontine tegmentum (PPT), using a single kainic acid injection, did not affect DA concentration in the ipsilateral striatum and nucleus accumbens when compared to sham-treated rats. DA levels in the contralateral striatum and nucleus accumbens of lesioned rats were significantly higher than ipsilateral levels. DOPAC/DA ratios were lower in the contralateral striatum and nucleus accumbens, suggesting decreased DA turnover. Glutamic acid decarboxylase activity was significantly higher in the ipsilateral than the contralateral SN. The physical manifestations of PD require a large reduction in caudate and putamen DA levels and no such depletion was measured in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

First month of neuroleptic treatment in schizophrenia: only partial normalization of the late positive components of visual ERP

In a previous study we recorded visual event-related potentials (ERP) in drug-naive schizophrenics during passive-attention and active-attention tasks. Patients, compared to normal controls, had much lower late positive components (LPC) in both sessions, but nearly normal LPC increase from passive to active task. The present sample consisted of drug-naive and drug-free patients who were tested before and during the first month of neuroleptic treatment. Neuroleptics initiated gradual amelioration of psychiatric symptoms expressed by reduced Brief Psychiatric Rating Scale (BPRS) scores. Schizophrenics compared to controls showed a session-related increase in LPC amplitude, but this process of LPC recovery was too minor to fully normalize the low LPC amplitudes in patients. Furthermore, the treatment either did not improve or even reduce the LPC reaction to the active-attention task. These findings indicate that normalization of low LPC in schizophrenia might require a long period of treatment, and that patients' reduced LPC reactivity to the task might be contributed, rather than treated, by neuroleptics.

Long-term effects of amygdaloid kindling on striatal dopaminergic terminals

The present study assessed the effects of kindling on striatal DA terminals. Kindled and control rats were tested for DA transporter density using [3H]GBR-12935 binding to striatal membranes and for amphetamine and KCl-induced [3H]DA release from striatal slices. Kindling decreased the maximal number of [3H]GBR-12935 binding sites in the dorsal striatum of rats sacrificed either 2 h or 4 weeks after the last seizure but had no effect on stimulated fractional [3H]DA release. These findings suggest a minor damage to DA terminals in the dorsal striatum. At the same postseizure time points, kindling augmented the hyperlocomotion associated with novel environment. Explanation of this effect requires in vivo measures of striatal DA functioning.

The effect of repeated amphetamine treatment on striatal DA transporter and rotation in rats

The effect of repeated amphetamine treatment on the involvement of the striatal DA transporters in rotation behavior was tested in rats. Repeated amphetamine treatment had no effect on [3H]DA uptake or [3H]GBR-12935 binding density. However, unlike the naive rats who rotated away from the striatum with a lower density of DA transporters, rats sensitized to amphetamine rotated toward the striatum with a lower density of DA transporters. These findings imply that repeated amphetamine augments the subcortical involvement in behavioral output.

[Diagnostic and therapeutic value of laparoscopic needle biopsies of persistent para-uterine cysts: absence of recurrences and consecutive pregnancies. In view of ultrasonography-guided biopsies]

In the presence of a persistent para-uterine cyst, the actual tendency is to operate by laparotomy or most frequently by laparoscopic surgery. This leads to ablation of 20% of the so called "Functional cysts". A 30 years experience of laparoscopic puncture of 745 persistent para-uterine cysts, among which 321 were preserved and controlled, shows that 69% of them, of various origin or nature do not recur, whereas many pregnancies happen to come at short notice: 59% of 117 patients who wished to be pregnant had 73 known living children. Young, nulliparous or sterile patients, could at a first step, under strict conditions, get the benefit of a sonographic-guided diagnostic and therapeutic puncture, avoiding a useless endoscopy or ablation.

Effect of amygdaloid kindling on rat striatal dopamine D1- and D2-receptors

The effect of kindling on dopaminergic (DA) neurotransmission was assessed by measuring dopamine D1- and D2-receptor binding in the dorsal and ventral striatum of rats either 2 hours (short-term) or 3-4 weeks (long-term) after the last kindled seizure. Kindling did not have any significant long-term effect on DA D2-receptor Kd or Bmax values in the dorsal or ventral striatum or on DA D1-receptor parameters in the dorsal striatum. The short-term effect of kindled seizures was to abolish the asymmetry in DA D2-receptor density observed in the dorsal striatum of control rats. DA D1-receptor density was also increased in the dorsal striatum contralateral to the kindled amygdala of short-term rats. The short-term effects support the notion that limbic seizures can modify the lateral imbalance of DA activity in the striatum.

Bilateral imbalance in striatal DA-uptake controls rotation behavior

We tested the relation between bilateral imbalance in striatal DA uptake and asymmetric rotation behavior. Rats were screened for either spontaneous or amphetamine-induced preferred direction of rotation and the presynaptic DA transporter in the ipsi- and contralateral striatum was characterized in vitro by measuring [3H]DA uptake or [3H]GBR-12935 binding. DA uptake was lower in the striatum contralateral to either the spontaneous or amphetamine-induced preferred direction of rotation. Similar imbalance in the density of the transporter was confirmed by the binding experiments. These results support the hypothesis that striatal imbalance in DA uptake produces asymmetric behavior during spontaneous rotation. Further studies are required to assess the involvement of DA transporter imbalance in amphetamine-induced behavioral asymmetry.

Unilateral inferior olive NMDA lesion leads to unilateral deficit in acquisition and retention of eyelid classical conditioning

New Zealand White rabbits (Oryctolagus cuniculus) were trained for acquisition (N = 21) or retention (N = 10) of classical eyelid conditioning with unilateral or bilateral N-methyl-DL-aspartate chemical lesions of the rostromedial dorsal accessory inferior olive (rmDAO; multiple injections totaling 76 to 342 nmol). In all instances, subjects were unable to learn or retain conditioning on the side contralateral to the lesion. Learning rates were comparable for lesions outside of the rmDAO and sham operates. These findings demonstrate a specific unilateral deficit whereas in previous research the answer to this question was ambiguous since electrolytic lesions effectively cause bilateral olivary lesions. This research agrees with the concept that the inferior olive projects essential information about the unconditioned stimulus to a cerebellar locus of learning and memory for classical conditioning.

Overexpression of nef as a marker for restricted HIV-1 infection of astrocytes in postmortem pediatric central nervous tissues

In previous studies, using polymerase chain reaction amplification of HIV-1 genes directly from pathologic tissues of children who died with AIDS encephalopathy, we showed that the reading frame of the HIV-1 regulatory nef gene is open, suggesting that the nef protein was expressed. We now show, using immunocytochemistry and in situ hybridization with nef-specific probes in postmortem pediatric CNS tissues, that nef mRNA and protein are present in up to 20% of astrocytes in tissue sections selected for extensive histopathology. By contrast, HIV-1 structural proteins such as gag and their coding mRNAs are present in multinucleated giant cells that harbor productive infection and are the hallmark of HIV-1 infection in the CNS. These findings are consistent with the nonproductive infection of glial cells observed in vitro, and imply that HIV-1 infection of astrocytes is restricted to early regulatory gene products, of which nef is the best target as it is expressed at high levels and is membrane-anchored. In developing central nervous tissues of children, restricted and latent HIV-1 infection of astrocytes may be extensive and contribute significantly to HIV-1 neuropathogenesis.

Clinical comparison of adult and pediatric NeuroAIDS

Human Immunodeficiency Virus type-1 (HIV-1)-associated neurologic disease occurs as the initial presenting clinical manifestation of acquired immunodeficiency syndrome (AIDS) in 3-7% of infected patients, but in up to 18% of children and adolescents (Janssen, 1992; Janssen et al., 1992; Scott et al., 1989; Mintz et al., 1989a; Epstein et al., 1986). The overall prevalence of dementia in adult AIDS patients is 7.3-11.3% (Janssen, 1992), but up to 30-60% of children with AIDS manifest an analogous progressive encephalopathy (Epstein et al., 1986; Belman et al., 1988; Mintz, 1992; The European Collaborative Study, 1990). As a result of both direct and indirect effects of HIV-1 infection of the central nervous system (CNS), a distinct clinical and pathologic picture has emerged of insidious and severe neurologic deterioration, termed "AIDS Dementia Complex" (ADC) in adults, and "HIV-1-associated Progressive Encephalopathy" (PE) in children (Working Group, 1991) (see Table 1). In the severe manifestations of this pariah, there is little dispute as to the necessity of CNS HIV-1 infection for precipitating the cascade of adverse neurologic symptoms, although the pathogenic mechanisms of neurologic dysfunction and destruction--whether a result of direct cellular infection of HIV, secondarily produced and upregulated cytotoxic cytokines, or co-infection with opportunistic pathogens--remains an area of active research (Epstein and Gendelman, 1993; Fiala et al., 1993; Wiley and Nelson, 1988; Saito et al., 1994; Koenig et al., 1986; Sharer, 1992). Furthermore, the existence of systemic immune deficiency renders the CNS susceptible to opportunistic infection (OI), particularly in adult patients, adding further to morbidity and mortality (Clifford and Campbell, 1992). With the introduction of antiretroviral nucleoside analogues, there have been reports of a decreasing incidence of ADC (Portegies et al., 1989; Day et al., 1992), and amelioration--at least temporarily--of PE in children (Pizzo et al., 1988; Mintz and Epstein, 1992; Brouwers et al., 1990; Mintz et al., 1990). This appends further evidence to the central precipitating role of CNS HIV-1 infection.

Effect of nootropic Solcoseryl on kainic acid-induced excitotoxic brain injury

Solcoseryl (S) has been shown to provide significant cytoprotection in a variety of models of cerebral hypoxia. In the present study, we quantified the epileptiform effects caused by kainic acid administered into the pontine reticular formation of rats and their response to S pretreatment. Compared to saline, the agent appeared to significantly reduce the mortality of rats in the course of status epilepticus. However, S-pretreated rats manifested an increased incidence of behavioral seizures. This untoward effect is attributed to the fact that S improves the functional potential of injured tissue and retards the period of metabolic exhaustion at a time when neuronal activity should be minimized.

Effect of an adenosine A1 agonist injected into substantia nigra on kindling of epileptic seizures and convulsion duration

The substantia nigra pars reticulata (SNr) has been reported to be critically involved in the development and propagation of epileptic seizures, while extracellular adenosine appears to be important for making seizures stop. In the present study, an adenosine A1 receptor agonist [N6-cyclohexyladenosine (CHA); 2.0 nmol/side, or vehicle] was injected bilaterally into the SNr shortly before each of the first five of a series of daily kindling stimuli delivered to the rat amygdala. Injections did not affect the acquisition of kindled afterdischarges or the rate at which seizures developed over subsequent kindling sessions, but convulsions occurring 48-72 h after treatment were significantly shortened. Thus, purinergic mechanisms in the SNr do not appear to be specifically involved in the acquisition of kindled seizures but may contribute to a postictal inhibitory process that shortens the convulsive component.

Dissociation of kainic acid lesion effects on the asymmetry of rotation and lateral head movements

The present study tested the relationship between horizontal head movement asymmetry and rotation behavior after unilateral kainic acid (KA) lesions of the pontine reticular formation (PRF). In line with previous studies, the lesions decreased the rate of ipsilateral spontaneous head movements and spared contralateral spontaneous head movements. In contrast to previous studies, however, these lesions facilitated ipsilateral rather than contralateral rotation. Histological analysis revealed that the ipsilateral rotation may be accounted for by distant effects of the KA injection in the PRF on the ipsilateral substantia nigra (SN). We conclude that unilateral lesions consisting solely of the PRF lead to a preference for contralateral horizontal head movements which then channel rotated away from the lesioned side. KA injections in the PRF, however, are also associated with distant lesions within the ipsilateral extrapyramidal system which override the channeling effect of the contralateral head movements and induce instead ipsilateral rotation.

Effect of amygdaloid kindling on [3H]dopamine and [14C]acetylcholine release from rat prefrontal cortex and striatal slices

The involvement of the dopaminergic (DA) systems in the control of limbic kindled seizures is ill defined. The effects of kindling on DA activity may have been overlooked in the past, because of its subtle unilateral occurrence and/or the variance of the endogenous imbalance of DA activity in normal animals. In the present study rats were screened for their endogenous DA imbalance using amphetamine-induced rotational behaviour. Electrical or sham kindling was applied in the hemisphere with the higher endogenous DA activity. Sections of the bilateral prefrontal cortex and dorsal and ventral striatum were dissected either 2 hours or 21 days after the final seizure and the electrically stimulated release of [3H]DA and [14C]acetylcholine (ACh) determined. Release was also measured in the presence of quinpirole or sulpiride to assess the activity of pre- and postsynaptic DA D2-receptors. Long-term effects of kindling consisted of facilitation of ACh release in the ventral striatum contralateral to the kindled amygdala and bilateral depression of DA release in the prefrontal cortex. Kindling therefore produced area specific changes in neurotransmitter systems giving rise to increased pro-convulsive cholinergic activity in the ventral striatum and decreased anti-convulsive dopaminergic activity in the prefrontal cortex.