Effect of lateral hypothalamic lesion on brown adipose tissue of Zucker lean and obese rats.

Acute (10-day) lateral hypothalamic (LH) lesion induced a reduction of food intake in both lean and obese Zucker rats which averaged about 50% over the course of the first 10 days. The aphagia associated with a fall in body weight in both genotypes which was greater than their respective pair-fed controls, indicating a change in energetic efficiency. The reduced level of BAT protein, mitochondria and GDP binding observed in the obese rat was restored after LH lesion, suggesting the reestablishment of a normal sympathetic drive to the tissue.

Human immunodeficiency virus replication in human brain cells. Brief report.

Human immunodeficiency virus (HIV), the etiologic agent of AIDS, was found to infect and replicate in human brain cells. The extent of HIV replication was minimal in human brain-derived cells in comparison to T4 lymphoid cells. These results suggest that direct infection of glial/neuronal cells by HIV may contribute to the CNS dysfunction frequently observed in HIV infected individuals.

Sodium butyrate activates human immunodeficiency virus long terminal repeat--directed expression.

To study the effect of sodium butyrate on human immunodeficiency virus (HIV) long terminal repeat (LTR)--directed expression, we constructed a chimeric plasmid (pLTR-CAT) in which the LTR sequences derived from a molecular clone of HIV were fused to the chloramphenicol acetyltransferase (CAT) gene. We used transient expression assays in transfected tissue culture cells to monitor the activity of the LTR. The expression of the pLTR-CAT plasmid was activated when the cells were exposed to butyrate after transfection.

Normal levels of serum corticosterone and hepatic glucocorticoid receptors in obese (fa/fa) rats.

In an attempt to understand the hyper-responsiveness to glucocorticoids that is characteristic of genetically obese fa/fa rats, we have measured the levels of free corticosterone in serum from lean and obese rats as well as the number of "cytosolic" and "nuclear" binding sites in livers of these rats. Both the lean and obese rats had similar amounts of free corticosterone available for biological activity at 4 weeks and 10 weeks of age. Measurement of glucocorticoid binding to hepatic glucocorticoid receptors failed to show any differences between genotypes leading to the suggestion that the abnormal glucocorticoid response in obese rats may be due either to post-receptor defects or to a permissive action of the steroid in the expression of the fa/fa genotype.

Response variability of somatosensory evoked potentials during scoliosis surgery.

Somatosensory evoked potentials (SSEP) were recorded from the scalp for intraoperative monitoring of patients undergoing surgical correction of spine deformities or spine fractures. Alterations in the SSEP with distraction, spine manipulation, anesthesia, hypotension, and other intraoperative variables are described. When loss of the SSEP occurred and a waiting period was undertaken until it returned, all patients with an SSEP present upon closing, which was within +/- 2 SD of their anesthetized control values, had no neurologic complications.

Transfusion-associated AIDS: donor-recipient human immunodeficiency virus exhibits genetic heterogeneity.

The genetic diversity of the human immunodeficiency virus (HIV) isolated from transfusion-associated AIDS patients has been examined. Restriction enzyme mapping studies of integrated proviral DNA of donor and recipient origin demonstrated genomic variation between isolates. Analysis of the molecularly cloned viral genomes of one donor-recipient pair showed that virus from the recipient had restriction enzyme site differences from the donor, noticeably clustered in the env and orf-2 regions, and also had a greater number of restriction sites in common with the donor as well.

Characteristics of a novel lentivirus derived from South African sheep with pulmonary adenocarcinoma (jaagsiekte).

A novel lentivirus was isolated from South African sheep with experimentally transmitted lung adenocarcinoma. Similar to visna virus and caprine arthritis encephalitis virus, this new strain induced cytopathic effects on ovine plexus choroid cultures. In contrast to a recent Israeli isolate from sheep with adenocarcinoma, the South African lentivirus could not transform fibroblast cultures.

Hypothalamic control of brown adipose tissue in Zucker lean and obese rats. Effect of electrical stimulation of the ventromedial nucleus and other hypothalamic centres.

Electrophysiological stimulation of the hypothalamic ventromedial nucleus (VMN) resulted in an increase in interscapular brown adipose tissue (BAT) temperature in both lean and obese (fa/fa) rats. Graded stimulations resulted in progressively larger temperature increases in both lean and obese (fa/fa) groups. Both intraperitoneal injection of propranolol and surgical denervation (but not sham denervation) abolished the increase in BAT temperature following VMN stimulation, in both lean and obese (fa/fa) groups.

Review of descending motor pathways involved with transcranial stimulation.

The anatomical basis of the pyramidal tract is reviewed with respect to its proposed role in the conduction of the motor evoked potential. The fiber diameter profiles are discussed in relation to the measured conduction velocities of the corticospinal tract in humans. Stimulus parameters utilized to obtain the motor evoked potential are reviewed in relation to the laterality of response, response threshold, and properties of spatial and temporal summation.

Energetic efficiency and brown adipose tissue uncoupling protein of obese Zucker rats fed high-carbohydrate and high-fat diets: the effects of adrenalectomy.

The influence of diet on the response of lean and obese fa/fa rats to adrenalectomy has been studied. Adrenalectomized and sham-operated rats were fed either a semi-synthetic high-carbohydrate (HC) or high-fat (HF) diet for 13 days. Energetic efficiency, calculated for measurements of energy storage and energy intake, was increased in obese rats fed both HC and HF diets and reduced close to values of lean rats after adrenalectomy.

Corticosterone inhibition of the intracerebroventricular effect of 2-deoxy-D-glucose on brown adipose tissue thermogenesis.

The effects on food intake, blood glucose and the binding of guanosine 5-diphosphate (GDP) to mitochondria from interscapular brown adipose tissue (IBAT) were examined following the injection of 2-deoxy-D-glucose (2-DOG) into the third ventricle of the brain. Microinjections of 2-DOG increased food intake and blood glucose within 30 to 60 min, but binding of GDP to mitochondria from IBAT, on the other hand, was reduced. The order of sensitivity to 2-DOG was IBAT--feeding--hyperglycemia.

Molecular characterization of human immunodeficiency virus from Zaire: nucleotide sequence analysis identifies conserved and variable domains in the envelope gene.

To examine the genetic relatedness of human immunodeficiency viruses (HIV) from different geographic locations, we molecularly cloned the genome of HIV isolated from a Zairian AIDS patient. Restriction mapping of the recombinant clone, designated HIV-Zr6, revealed both common (as observed in other HIV isolates) and unique restriction sites. The DNA clone of HIV-Zr6, shown to give rise to infectious cytopathic virus after transfection of cultured lymphoid cells, was sequenced in several regions.

Rodent and primate monolayer cells support the expression and assembly of viral particles directed by human immunodeficiency virus (HIV) proviral DNA.

A molecular clone of human immunodeficiency virus (HIV) was transferred to rodent and primate monolayer cells by DNA transfection. Of the cell lines tested, all of them released viral particles as shown by reverse transcriptase assay and dot-blot hybridization. The viruses released from transfected cultures were able to establish infection of human T-cell line HUT 78.

Nonpyramidal motor activation produced by stimulation of the cerebellum, direct or transcranial: a cerebellar evoked potential.

There is a need to monitor the functional status of the motor pathways well enough to predict the state of that function during operations and in injured or diseased patients. We previously reported that a motor evoked potential (MEP) can be produced by direct or transcranial stimulation of the motor cortex in both cats and humans. This signal descends through both the dorsolateral and ventral spinal cord and is primarily localized in the pyramidal tracts, producing a peripheral nerve signal and an electromyogram (EMG) response.

Motor evoked potential in cats with acute spinal cord injury.

We have previously reported that a motor evoked potential (MEP) can be produced by transcranial stimulation of the motor cortex in cats and humans. This signal travels in both dorsolateral and ventral spinal cord. We report here the evaluation of this evoked potential in comparison to the somatosensory evoked potential (SEP) in an acute spinal cord weight drop model.

Correlation between a unilateral midbrain-pontine lesion and abnormalities of brain-stem auditory evoked potential.

Brain-stem auditory evoked potentials (BAEPs) were evaluated over a 39 day period in a patient with a unilateral pontine-midbrain lesion verified by CAT scan and at autopsy. Waves I, II and III were present on the side of lesion, whereas all 5 waves were present on the side opposite the lesion. The findings suggest that the BAEPs may be obtained with only an intact ipsilateral auditory pathway.

Thermogenesis and sympathetic activity in BAT of overfed rats after adrenalectomy.

Resting oxygen consumption was elevated by 30% in young rats fed a cafeteria diet compared with their chow-fed controls and by 22% in cafeteria-fed, adrenalectomized (ADX) rats compared with the ADX chow-fed group, but injection of propranolol reduced oxygen consumption in the cafeteria-fed animals and abolished these differences. Brown adipose tissue (BAT) mass was increased by cafeteria feeding, and the activity of the mitochondrial proton conductance pathway (assessed from purine nucleotide binding) was enhanced by adrenalectomy and by cafeteria feeding. Norepinephrine turnover in BAT (determined from the time-dependent loss of tissue [3H]norepinephrine specific activity) was increased by 105% in sham-operated, cafeteria-fed rats, by 142% in chow-fed ADX rats, and by 400% in cafeteria-fed ADX rats, compared with chow-fed controls.

Isolation and identification of a South African lentivirus from jaagsiekte lungs.

In the course of attempts to grow the jaagsiekte retrovirus in cell culture, a typical lentivirus was isolated for the first time in South Africa from adenomatous lungs. Morphologically the virus could not be distinguished from other lentiviruses, but serologically it was shown to be more closely related to visna virus than to caprine arthritis-encephalitis virus. However, a preliminary restriction enzyme analysis of the linear proviral DNA of this new lentivirus (SA-DMVV) revealed that it is significantly district from visna virus and CAEV and therefore may represent a third type of lentivirus.

The effect of cigarette smoking on the thermic response to feeding.

Resting energy expenditures, the thermic responses to a standard meal (2.09 MJ 'Ensure') and energy intakes were measured in eight age/weight matched pairs of female smokers and non-smokers. The mean thermic response to the standard meal (including the thermic effects of smoking) was 35 percent greater for the smokers when compared with the mean thermic response to the standard meal alone shown by the non-smoker controls (P less than 0.

Studies on the mechanism of membrane fusion: site-specific mutagenesis of the hemagglutinin of influenza virus.

Oligonucleotide-directed mutagenesis of a cDNA encoding the hemagglutinin of influenza virus has been used to introduce single base changes into the sequence that codes for the conserved apolar "fusion peptide" at the amino-terminus of the HA2 subunit. The mutant sequences replaced the wild-type gene in SV40-HA recombinant virus vectors, and the altered HA proteins were expressed in simian cells. Three mutants have been constructed that introduce single, nonconservative amino acid changes in the fusion peptide, and three fusion phenotypes were observed: substitution of glutamic acid for the glycine residue at the amino-terminus of HA2 abolished all fusion activity; substitution of glutamic acid for the glycine residue at position 4 in HA2 raised the threshold pH and decreased the efficiency of fusion; and, finally, extension of the hydrophobic stretch by replacement of the glutamic acid at position 11 with glycine yielded a mutant protein that induced fusion of erythrocytes with cells with the same efficiency and pH profile as the wild-type protein.

The effects of 2-deoxy-D-glucose on brown adipose tissue of lean and obese Zucker rats.

The response of brown adipose tissue (BAT) thermogenesis, as measured by mitochondrial GDP binding, of lean and obese Zucker fa/fa rats to 2-deoxy-D-glucose (2-DOG) has been investigated. 2-DOG reduced BAT mitochondrial GDP binding of lean rats but had no effect in obese rats. Adrenalectomy increased BAT GDP binding in obese rats and restored the 2-DOG inhibitory effect.