Regulation of dietary fat preference: establishing a reproducible profile of dietary fat preference in rats

The mechanism(s) underlying preference for individual macronutrients (particularly fat) in diet are poorly understood. The greatest obstacle in designing experiments to define neurochemical determinants of fat preference lies in our ability to clearly identify animals' macronutrient preference (MP) profile. To this end, we have defined the role of several variables and suggested ways to design better studies to examine the mechanism of macronutrient preference. The results of these studies show that the paradigm used for MP analysis, genetics and age of the animal could clearly affect the MP profile.

Ethanol modulation of GABA receptor-activated Cl- currents in neurons of the chick, rat and mouse central nervous system

Modulation of gamma-aminobutyric acidA (GABAA) receptor function by drugs such as ethanol may depend on the genetic heterogeneity of GABAA receptor subunits, which vary across species and cell types. For this reason, the effects of ethanol on gamma-aminobutyric acid receptor-activated chloride currents (IGABA) were examined using whole-cell voltage-clamp recordings in primary cultures of neurons obtained from different species (chick, mouse and rat) and from different brain regions (cerebral cortex, hippocampus, cerebellum and spinal cord), and in acutely dissociated neurons from rat neocortical slices. Low concentrations (1-50 mM) of ethanol produced an enhancement of IGABA in some cells from each brain region examined. In cells obtained from the rat and chick cerebral cortex, 40-58% of cells exhibited an ethanol-sensitive IGABA. Moreover, a statistically significant variation in the response to ethanol was found in rat cortical neurons obtained from different litters. In mouse hippocampal neurons, potentiation of IGABA was obtained with ethanol concentrations (1-10 mM) well below those needed to inhibit neuronal responses to N-methyl-D-aspartic acid (30-50 mM), suggesting a differential sensitivity of these two receptor mechanisms to ethanol. Potentiation of IGABA by ethanol was reversed by the benzodiazepine receptor partial inverse agonist RO15-4513 (ethyl 8-azido-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine - 3-carboxylate), but was not affected by chelation of intracellular calcium. Furthermore, high concentrations of GABA attenuated the ability of ethanol to enhance IGABA. These results are consistent with the hypothesis that ethanol facilitates coupling between receptor binding and chloride channel activation.

Resistance to insulin-induced hyperphagia in fat-preferring rats

Outbred male Sprague-Dawley rats were screened for their macronutrient (fat, carbohydrate and protein) preference profile and divided into two groups, the low- and high fat-preferring groups each deriving 23% and 72% of its total caloric intake from fat respectively. Subcutaneous administration of bovine insulin (6U/kg) resulted in an increase in total caloric intake in the low, but not the high fat-preferring group. Furthermore, the increased caloric intake in the low fat-preferring group was entirely due to increased carbohydrate consumption. These data suggest a defect in the action of insulin in fat-preferring rats.

Uncoupling of GABA-benzodiazepine receptors in chick cerebral cortical neurons requires co-activation of both receptor sites

Primary cultures of chick cerebral cortical neurons were exposed to 1 microM flurazepam in vitro, and the effect of flurazepam on GABA-activated membrane current (IGABA) was examined using whole-cell voltage-clamp recording. Exposure of chick cerebral cortical neurons to flurazepam alone for 3-10 days resulted in a significant decrease in the degree of potentiation of IGABA elicited by 0.5 microM flurazepam. When GABA or nipecotic acid (a GABA uptake blocker) were added with flurazepam during chronic drug exposure, neuronal responses to GABA were significantly less sensitive to modulation by 0.5 microM flurazepam compared to flurazepam treatment alone. Furthermore, this effect was significantly reduced by co-administration of the GABAA receptor antagonist bicuculline. These results suggest that tolerance to benzodiazepines in vitro requires activation of both the GABA and the benzodiazepine binding sites on the GABAA receptor-channel complex.

Solitary spinal osteochondroma causing neural syndromes

Three cases of solitary osteochondroma of the spine are reported. Two presented with cervical myelopathy and one with radiculopathy. Plain radiography or tomography is adequate for the diagnosis in the majority of cases; nevertheless, a CT scan or MRI is of immense help in planning surgical treatment. The radiological features of spinal exostoses are reviewed.

Cryptogenic osteomyelitis of the skull and intracerebral abscess

The authors report a rare case of cryptogenic osteomyelitis of the skull with an intracerebral and a subgaleal abscess. Total excision of the abscess extending from the cortical surface to the lateral ventricle led to ventriculitis and subgaleal cerebrospinal fluid collection. These complications could have been avoided by aspirating the abscess after removing the infected portion of the skull and the epidural granulation tissue. Neurosurgeons preferring to excise such an abscess should leave a small area of capsule at the base in order to avoid having to open the ventricle.

Ethanol enhances GABAA receptor-activated chloride currents in chick cerebral cortical neurons

Primary cultures of cerebral cortical neurons were prepared from 7- to 8-day-old chick embryos. The effect of ethanol on GABA-activated membrane current was examined using whole-cell voltage-clamp recording in cells maintained for 3-25 days in vitro. In approximately 60% of neurons examined ethanol caused a potentiation of the membrane current elicited by GABA. The threshold concentration of ethanol was 1 mM, and the potentiating effect of ethanol on GABA-activated currents was maximal at 10 mM. In many cells higher concentration (40-50 mM) of ethanol inhibited GABA-activated currents. These effects of ethanol were all reversible.

Acute ataxic neuropathy: a clinical, electrophysiological and morphological study

Sensory ataxia as the chief manifestation of acute neuropathy is rather rare. Of the 224 cases of acute polyneuropathy seen over 6 years (1984-1990) only 10 patients (M:F 3:7) had disabling ataxia as the presenting feature. Their ages ranged from 14-61 years. Antecedent febrile illness was present in 6 patients and the peak deficit evolved over 2-25 days. Severe ataxia, paresthesia, distal areflexia and predominant joint sense loss were common to all, motor weakness was either absent or insignificant. CSF was acellular and revealed elevated protein in 3 subjects. All patients had electrophysiological evidence of severe sensory neuropathy with mild or no motor neuropathy. Sural nerve biopsy in one patient showed loss of large, as well as small, diameter myelinated fibres, secondary demyelination, but no evidence of inflammation. At follow up marginal to moderate improvement in ataxia was noted in only 5 patients. Absence of ophthalmoplegia and motor weakness, poor prognosis and characteristic electrophysiological and histopathological observations suggest that acute ataxic neuropathy may be a distinct entity.

Evaluation of glare in normal and pseudophakic subjects

It has been difficult to document the subjective complaint of glare. Devices to quantify this problem include the Miller-Nadler glare tester (MNGT) and the brightness acuity tester (BAT). We used these devices to evaluate a group of pseudophakic subjects (15 eyes with posterior-chamber intraocular lenses) and a group of normal subjects (32 low myopic eyes). A subject's ability to discern contrast with a background glare source is measured as a percentage with the MNGT. The number of lines lost on the Snellen chart as a light is brightened progressively over the line of vision is the BAT score. A Wilcoxon signed-ranks test showed no significant change without correction (SC) to with correction (CC) with the BAT but was significant at P less than .001 with the MNGT. The BAT scores for the normal group CC (mean, 0.59) compared with the intraocular lens group CC (mean, 3.0) with the Mann-Whitney U test showed a statistically significant difference (P less than .001). There also was a difference with the MNGT between normal group CC (mean, 5.1%) and pseudophakic group CC (mean, 8.9%) at P less than .001). These results suggest that pseudophakic subjects have marked visual dysfunction secondary to glare. The BAT, however, showed a more easily quantifiable change unaffected by spectacle correction.

Development and migration of avian sympathetic preganglionic neurons

Modern neuronanatomical techniques were used to investigate the development of the avian sympathetic preganglionic cell column in the spinal cord of the chick embryo. [3H]thymidine autoradiography indicated that the majority of these preganglionic, or "Terni column" neurons are generated between stages 18 and 24 (days 2-4). This coincides with the genesis of the somatic motoneurons in the thoracic levels of the cord, and therefore differences in the time of origin cannot explain the divergent fates of these two neuronal populations. Data obtained from short-survival autoradiographic experiments indicated that many early born cells remain close to the ventral region of the ventricular epithelium until day 5 of incubation. Ventral root injections used to label retrogradely neurons projecting an axon into the ventral root (Terni cells and somatic motoneurons) have labeled neurons next to the ventricular epithelium at the same early stages. Thus, it seems likely that some Terni cells, if not all, maintain medial positions and do not migrate laterally to join a common motor column before initiating a dorsal migration. Analysis of a closely staged series of embryos, whose Terni column neurons were retrogradely labeled with wheat germ agglutinin-horseradish peroxidase (WGA-HRP), revealed that between days 5 and 8 of incubation, Terni column neurons migrated dorsally to attain their adult position adjacent to the central canal. These changes in position were reflected in the changing morphology of the Terni column neurons, visualized by the Golgi-like HRP labeling. The positions of the migrating Terni cells differed from those of commissural cells, indicating that these fibers are not the substrate for the dorsal migration. The dorsal migration of Terni column cells was not disrupted by the surgical removal of the sympathetic ganglia, the synaptic targets of these neurons, nor by disruption of spinal afferents. Taken together, these results suggest that the migratory behavior of Terni cells in distinctive when compared to that of somatic motoneurons, and that local and/or intrinsic cues within the spinal cord guide the dorsal migration of Terni column cells.

Lymphocytic hypophysitis: can open exploration of the sella be avoided?

A case of lymphocytic hypophysitis (LYHY) in a menopausal woman is presented. A review of the literature suggests that conservative treatment may be tried in suspected cases of LYHY, if the vision of the patient is not threatened. A transphenoidal stereotactic biopsy of the mass may be performed if the patient fails to improve or deteriorates, thus avoiding open exploration of the sella in selected cases.

Medulloblastoma with extensive calcification

Calcification in cases of medulloblastoma has been described with varying frequency (10%-15.4%) on computed tomographic (CT) scan. Usually these calcifications are small in size and speckled. The authors report a case of medulloblastoma with extensive calcification in the lateral hemisphere of the cerebellum in an 18-year-old boy.

Cystatins in human tear fluid

The activities of cysteine proteinases which include several lysosomal cathepsins are controlled by naturally occurring inhibitory proteins termed cystatins. Cystatins occur both intracellularly and extracellularly in various tissue fluids including tears. Tears were collected by the Schirmer paper strip method from healthy volunteers who had no history or signs of external ocular disease. The tear components were extracted from the filter papers, and used to determine the apparent free cystatin activity and cystatin levels of tears, and for immunoblots. Tears were also collected using capillary tubes for the measurements of cystatins. By titrating papain, a cysteine proteinase, of known specific activity with tear fluid, relatively high levels of apparent free cystatin activity were demonstrated in tears: 28.8 +/- 3.47 (S.E.M.) pmols papain inhibited per mg tear protein (n = 9). The concentrations of cystatins in tear samples were measured by an indirect enzyme-linked immunosorbent assay (ELISA) using antibodies against human salivary cystatin S and purified cystatin S as standard. The ELISAS revealed that tears contain high levels of cystatin-like immunoreactive material, amounting to about 10% of tear proteins. In microgram cystatin S/mg protein the values were: right eye: 94.7 +/- 9.9; left eye: 115.5 +/- 14.8; n = 12. Cystatin levels of tears collected using capillary tubes were comparable: 120.7 +/- 19 micrograms/mg protein (n = 10). Immunoblots of tear fluids revealed a protein of about 14,000 molecular weight which reacted with antihuman cystatin SN monoclonal antibodies. Protein(s) of similar molecular weight were visualized using antibodies against human cystatins S and C. Less abundant additional cystatin-like immuno-reactive proteins were detected by using the two latter antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of the perforated segment of the ventricular catheter in cerebrospinal fluid leakage into the brain

Two cases of gross post-operative cerebrospinal fluid (CSF) leakage along an indwelling ventricular catheter are reported. The CSF appeared to leak through the perforations of the ventricular catheter, as well as at the site of penetration of the ventricular wall. A small or slit ventricle with high intraventricular pressure may thus be a predisposing factor for this localized CSF collection.

Psychiatric morbidity, platelet monoamine oxidase and tribulin output in headache

A significantly higher proportion of patients with headache showed scores in the psychopathological range of the General Health Questionnaire (GHQ) compared with controls, with ratings particularly high on the anxiety and depression subscales. Across the whole group, there was a significant negative correlation between platelet monoamine oxidase (MAO) activity and GHQ score overall, and with the anxiety and depression subscales. There was a significant positive correlation between platelet MAO activity and urinary output of the endogenous MAO inhibitor, tribulin. Within the migraine group, there was a significant negative correlation between tribulin output and GHQ score. These findings suggest that the biochemical nature of the anxiety associated with migraine may differ from that in other conditions such as generalized anxiety disorder where high platelet MAO activity and high tribulin output have been reported.

Altered amount and activity of superoxide dismutase in sickle cell anemia

The amount and activity of superoxide dismutase (SOD) (EC 1.15.1.1) were measured in red cells collected from 50 white controls, 101 black controls, 50 patients with sickle hemoglobin (SS Hb), 12 with sickle trait, and 11 with other sickling hemoglobinopathies. Red cells from normal black subjects had more SOD amount and activity than normal whites (1.77 U/mg Hb and 2.96 micrograms/mg Hb vs. 1.47 U/mg Hb and 2.64 micrograms/mg Hb, respectively) or blacks with SS Hb or other sickling hemoglobinopathies. Patients with more severe manifestations of SS Hb had lower levels of SOD activity than those with milder symptoms but had the same amount of enzyme protein. Individuals with sickle trait had amounts and activities of SOD comparable to black controls. An alteration in defense to free radical oxygen may play a role in the severity of symptoms experienced by patients with homozygous sickle cell disease.

Enhanced pressor sensitivity to oral tyramine challenge following high dose selegiline treatment

Blood pressure and heart rate responses to oral tyramine have been measured in healthy volunteers before and after administration of the selective monoamine oxidase B inhibitor selegiline at high dosage (30 mg/day). Treatment brought about a 2 to 4-fold increase in tyramine sensitivity and a concomitant small but significant reduction in plasma 4-hydroxy-3-methoxyphenylglycol concentration, pointing to the emergence of some degree of monoamine oxidase A inhibition. It is suggested that patients treated with selegiline 30 mg/day or more should be placed on a tyramine-free diet.

Psychiatric morbidity and platelet monoamine oxidase activity in cancer patients

Psychometric ratings for both anxiety and depression in 30 cancer patients were significantly elevated compared with values in 16 controls. The scores were especially high in the 14 patients who did not have breast cancer. This group also had significantly greater platelet monoamine oxidase activity than either the breast cancer patients or controls. Platelet monoamine oxidase activity values correlated significantly with both depression and anxiety scores in the whole cancer group.

The treatment of Wilson's disease with zinc. IV. Efficacy monitoring using urine and plasma copper

Progress has been made in establishing the efficacy and safety of oral zinc as a maintenance therapy for Wilson's disease. It is important to develop simple, noninvasive monitoring methods to assure the adequacy of zinc therapy in individual patients. In this paper we report the use of 24-hr urine copper and plasma copper measurements to monitor efficacy of zinc maintenance therapy in 30 Wilson's disease patients. In examples of therapeutic inadequacy such as noncompliance, these values increase. With continued long-term adequate therapy, they remain stable or decrease. These two simple monitoring tools appear to be very useful in monitoring Wilson's disease patients receiving zinc therapy.

Interrelationships between zinc and immune function

Zinc deficiency is a common nutritional problem observed both in human and in animal populations that has profound effects on host defense mechanisms. Using the young adult mouse as a model, it has been demonstrated that a moderate period of suboptimal zinc causes thymic atrophy, lymphopenia, and alterations in the proportions of the various subsets of lymphocytes and mononuclear phagocytes. As a result, antibody-mediated responses to both T cell-dependent and T cell independent antigens are significantly reduced. Cytolytic T cell responses, natural killer (NK) cell activity, and delayed-type hypersensitivity (DTH) reactions are also depressed. Suboptimal zinc during in utero development of mice causes persistent states of immunodeficiency in the offspring that can even be transferred to subsequent generations. In regard to human immunological consequences of zinc deficiency, patients with the genetic disorder of zinc absorption, acrodermatitis enteropathica, also exhibit atrophic thymuses, lymphopenia, anergic DTH responses, and reduced NK cell activity. Patients suffering from sickle cell anemia or uremia with associated deficiencies in zinc exhibit similar immune deficiencies. An additional outcome of these studies has been shown to be an essential cofactor for thymulin, one of the thymic hormones. Furthermore, addition of zinc salts to culture can polyclonally activate lymphocytes as well as augment responses to mitogens in adjuvant-like manner.

Efficacy of trazodone as an anti-obsessional agent

Eight patients with chronic obsessive-compulsive neurosis were subjected to trazodone, an antidepressant acting on the serotonergic system. After 4 weeks of treatment, 6 showed significant reduction in the obsessional symptoms which was sustained after a 6-week follow-up. The 2 patients who did not show improvement had a significantly higher trait score than the others on psychometric ratings.

Multiple personality syndrome

Multiple personality syndrome is one of the most fascinating conditions encountered in psychiatric practice. Although its existence has been known for nearly two centuries, there is a relative sparcity of literature on this condition and its importance is underemphasized in psychiatric training. My theory is that this is a far more common condition than has been hitherto realized and the lack of case reports is largely a manifestation of the lack of awareness of diagnostic criteria.

Efficacy of trazodone as an anti obsessional agent

Eight patients with chronic Obsessive-Compulsive Neurosis were subjected to Trazodone, an antidepressant acting on the serotinergic system. After 4 weeks of treatment, 6 showed significant reduction in the obsessional symptoms which was sustained after a 6-week follow-up. The 2 patients who did not show improvement had a significantly higher trait score than the others on psychometric ratings.

A double blind study of imipramine versus zimelidine in treatment of obsessive compulsive neurosis

Six patients suffering from obsessive compulsive neurosis were randomly allocated into two groups of three patients each and commenced on either imipramine, a noradrenaline re-uptake inhibitor, or zimelidine, a serotonin re-uptake inhibitor. After 4 weeks, the group on zimelidine showed significant reduction of obsessional symptoms as compared to the other group. The response was rapid and sustained over a period of two months.

Chronic lithium intake and hyperparathyroidism

Two cases of patients on long-term lithium therapy are reported who developed hyperparathyroidism. The onset of this coincided with the appearance of severe depressive symptoms which had previously been under control.

Attempted suicide by jumping

A series of 18 patients who attempted suicide by jumping is reported. All were diagnosed as being psychiatrically ill and 14 received psychiatric treatment after the episode. These patients differ in several important aspects from those who harm themselves by drug-overdose.

Successful treatment of obsessive-compulsive disorder with zimelidine, a serotonin re-uptake inhibitor

A 37 year old lady with severe obsessive-compulsive features which figured on Leyton's inventory was successfully treated with Zimelidine, a serotonin re-uptake inhibitor. Her response was rapid and associated with improvement in her mood. Two months later, she had still not relapsed and was maintaining her improvement.