Retroviruses and schizophrenia in Jamaica

Reports of an 18-fold higher incidence of schizophrenia among second-generation Afro-Caribbeans, and especially Jamaican migrants in the United Kingdom were soon called “an epidemic of schizophrenia,” with the inference that a novel virus, likely to be perinatally transmitted, was a possible etiological agent. This intriguing observation led us to explore a possible link with human T-cell lymphotropic virus type one (HTLV-I), because it is a virus that is endemic in the Caribbean Islands, is perinatally transmitted, known to be neuropathogenic, and the cause of a chronic myelopathy (tropical spastic paraparesis/ HTLV-I associated myelopathy). We therefore examined inpatients at the Bellevue Mental Hospital, Kingston, Jamaica and did standard serological tests for retroviruses HTLV-I and HTLV-II and HIV-I and HIV-II on 201 inpatients who fulfilled ICD-9 and DSM III-R criteria for schizophrenia. Our results produced important negative data, since the seropositivity rates for HTLV-I, the most likely pathogen, were no greater than the seropositivity range for HTLV-I carriers in this island population, indicating that HTLV-I and the other retroviruses tested do not play a primary etiological role in Jamaican schizophrenics.     

Poliomyelitis outbreak in Natal/KwaZulu, South Africa, 1987-1988. 1. Epidemiology.

An epidemic of type 1 poliomyelitis occurred in Natal/KwaZulu in the eastern part of South Africa between December 1987 and November 1988. 412 poliomyelitis cases were reported, of whom 74% were younger than 5 years. The case-fatality rate was 8%. It is suggested that massive floods, experienced in the area 2 months earlier, triggered the outbreak.     

Effects of prostaglandins and the autonomic nervous system on the vasodilatory properties of nitroglycerin in conscious dogs.

This study was designed to assess the respective roles of prostaglandins and the autonomic nervous system in the responses to nitroglycerin (NTG) in conscious dogs. In vivo, NTG (1, 10, and 100 micrograms/kg i.v.) induced dose-dependent decreases in blood pressure and increases in heart rate and cardiac output. Coronary and carotid blood flows increased simultaneously, whereas responses in renal blood flow were biphasic, i.e., an initial decrease was followed by an increase above control at 10 and 100 micrograms/kg. NTG responses were not changed by indomethacin but were affected by chlorisondamine alone or in combination with indomethacin; tachycardia was abolished, and increases in cardiac output after 10 and 100 micrograms/kg were reduced by 26 and 32%, respectively, after ganglionic blockade and by 19 and 32%, respectively, after chlorisondamine plus indomethacin. In addition, increases in carotid blood flow in doses of 100 micrograms/kg were reduced by 88% after chlorisondamine and 83% after chlorisondamine plus indomethacin. Finally, in the presence of chlorisondamine plus indomethacin, NTG induced a more pronounced hypotension associated with a more pronounced renal vasodilation at the highest dose. Independent of indomethacin pretreatment, NTG in vitro induced a dose-dependent relaxation of the carotid, coronary, and renal arteries. Depending on the vascular bed, the reflex and local controls of circulation are affected differently by NTG.     

Prevalence of Legionella in pharyngeal secretions of patients with pharyngitis

A serological investigation has suggested that Legionella pneumophila may be associated with sore throat in adults. In a study of 177 adults and children with acute pharyngitis, Legionella species were not isolated from pharyngeal cultures, which utilized selective and nonselective buffered charcoal-yeast extract media. Group A beta-hemolytic streptococci were isolated from 14 percent of the 177 symptomatic patients. Throat cultures from 88 asymptomatic control subjects were negative for Legionella and beta-hemolytic streptococci. Further studies are needed to determine if Legionella species are associated with acute pharyngitis.     

Do viscous polysaccharides slow absorption by inhibiting diffusion or convection?

Viscous polysaccharides such as guar gum delay absorption probably by impairing the access of luminal contents to the absorptive epithelium. Measurements of the electrical resistivity of saline solutions were carried out to determine if guar gum (0.5, 0.75 and 1 per cent w/v), in concentrations which impaired absorption in vitro, delayed diffusion of solutes or inhibited convection of luminal contents. Our results indicated that guar had no effect on the mobility of ions in a completely unstirred solution but delayed the time taken for saline solutions of different resistivity to achieve complete mixing, when they were brought into contact inside a vessel, which was rotated at a constant speed. The time taken to achieve complete mixing was directly related to the viscosity of the guar solutions. The effect of intestinal contraction on the absorption of glucose was simulated in an in vitro model, consisting of a length of dialysis tubing, alternately contracted at each end. Movement of glucose out of the dialysis tubing was increased by increasing the rate of contraction. The incorporation of guar gum into the solution prevented the rise in glucose uptake produced by increasing the rate of contraction. These effects suggest that guar probably reduces absorption by resisting the convective effects of intestinal contractions.     

A case of Datisca glomerata poisoning in beef cattle

Six of 175 Angus heifers died after ingesting excessive amounts of Durango root (Datisca glomerata). Animals had rumens full of Durango root, were extremely lethargic, and had diarrhea prior to death. The animals had nonspecific postmortem lesions. This case is discussed in light of previous findings from trials in which Durango root was experimentally fed to cattle.