Persistent infection of rhesus macaques with a molecular clone of human immunodeficiency virus type 2: evidence of minimal genetic drift and low pathogenetic effects.

In an attempt to generate a suitable animal model to study the infectivity and possible pathogenicity of human immunodeficiency viruses, we intravenously inoculated juvenile rhesus macaques and African green monkeys with a molecularly cloned virus, human immunodeficiency virus type 2 HIV-2sbl/isy, as well as with the uncloned HIV-2nih-z virus. Infection was monitored by virus recovery from the peripheral blood cells and by seroconversion against HIV-2 antigens measured by Western immunoblot, radioimmunoprecipitation, and enzyme-linked immunosorbent assay. We successfully infected two out of two macaques with the molecularly cloned virus and one macaque out of two with the HIV-2nih-z. No evidence of infection was seen in the African green monkeys with either virus. We followed the infected animals for 2 years. The animals remained healthy, although we observed intermittent lymphadenopathy and a transient decrease in the absolute number of circulating CD4+ T lymphocytes in both animals infected with the molecularly cloned virus. Virus isolation from the peripheral blood cells of the infected animals was successful only within the first few months after inoculation. Evidence of persistent infection was provided by the detection of proviral DNA by polymerase chain reaction analysis of the blood cells of the inoculated animals and by the stability of antiviral antibody titers. To evaluate the genetic drift of the proviral DNA, we molecularly cloned viruses which were reisolated 1 and 5 months postinoculation from one of these animals. Comparison of the DNA sequences of the envelope genes of both these isolates indicated that a low degree of variation (0.2%) in the envelope protein had occurred in vivo during the 5-month period. These data suggest that the use of HIV-2sbl/isy in rhesus macaques may represent a good animal model system to study prevention of viral infection. In particular, molecularly cloned virus can be manipulated for functional studies of viral genes in the pathogenesis of acquired immune deficiency syndrome and provides a reproducible source of virus for vaccine studies.     

Coccidian parasites (Apicomplexa: Eimeriidae) from insectivores. VII. Six new species from the hairy-tailed mole, Parascalops breweri

Sixteen hairy-tailed moles, Parascalops breweri, collected from the northeastern U.S.A. were examined for coccidian oocysts; all were infected with multiple species of coccidia and 3 genera were represented. Two cyclosporans, 2 eimerians, and 2 isosporans are described as new species. Sporulated oocysts of Cyclospora ashtabulensis n. sp. are subspheroid to ellipsoid, 18 X 14 (14-23 X 11-19) microns, and sporocysts are ovoid, 12 X 7 (8-14 X 5-9) microns; C. ashtabulensis was found in 7 of 16 (44%) moles. Sporulated oocysts of Cyclospora parascalopi n. sp. are spheroid, 17 X 14 (13-20 X 11-20) microns, and sporocysts are ovoid, 11 X 7 (8-14 X 5-8) microns; C. parascalopi was found in 8 of 16 (50%) moles. Sporulated oocysts of Eimeria aethiospora n. sp. are subspheroid to ellipsoid, 19 X 13 (15-24 X 10-16) microns, and sporocysts are ovoid, 11 X 6 (8-13 X 4-7) microns; E. aethiospora was found in 4 of 16 (25%) moles. Sporulated oocysts of Eimeria titthus n. sp. are subspheroid, 16 X 14 (13-19 X 11-17) microns, and sporocysts are ellipsoid, 11 X 6 (9-13 X 4-7) microns; E. titthus was found in 4 of 16 (25%) moles. Sporulated oocysts of Isospora ashtabulensis n. sp. are ellipsoid, 20 X 14 (16-24 X 10-18) microns, and sporocysts are ovoid, 10 X 7 (7-14 X 5-10) microns; I. ashtabulensis was found in 5 of 16 (31%) moles.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phytohormone-induced GABA production in transformed root cultures of Datura stramonium: an in vivo 15N NMR study

Primary nitrogen metabolism in transformed root cultures ofDatura stramonium was observed by in vivo ¹⁵N NMR. Treatmentof the root cultures with the plant growth regulators -naphthaleneaceticacid (NAA) and kinetin caused a de-differentiation of the roottissue, together with perturbation of primary and secondarynitrogen metabolism. The levels of newly-synthesized glutamineand glutamate during ammonium assimilation were depleted relativeto control cultures, whereas GABA biosynthesis was enhanced.Although GABA production could be stimulated by a decrease incytoplasmic pH (whether imposed artificially or induced by hypoxia),observation of the roots during phytohormone treatment by ³¹PNMR showed that the cytoplasmic pH remained stable, indicatingthat the perturbation of nitrogen metabolism in the de-differentiatedroots must be due to other causes. Key words: Datura, -aminobutyric acid, nitrogen metabolism, NMR, root cultures     

Developmental progression of Gpd expression from the inactive X chromosome of the virginia opossum

Metatherian (marsupial) mammals possess a non-random form of X-chromosome inactivation in which the paternally-derived X is always the one inactivated. To examine the progression of X-linked gene expression during metatherian development, we compared relative levels of the maternally and paternally encoded Gpd gene products in heterozygous female Virginia opossums (Didelphis virginiana) across a moior portion of the developmental period. Panels of tissues obtained from fetuses, newborns, and pouch young were examined via polyacrylamide gel electrophoresis of the G6PD protein. As in adults, G6PD phenotypes in these developmental stages were highly skewed in favor of the maternal allele product, but in some tissues there was a marked increase in paternal allele expression with advancing developmental age. However, even by 42 days of post-partum development, expression of the paternal Gpd allele had not attained the adult, tissue-specific activity pattern. Our findings indicate remarkable developmental changes in the activity of the paternal allele in several tissues/organs continuing well into mid pouch-life stages and beyond. Specifically we found that 1) a substantially repressed paternal Gpdgene is present in the cells of female stage 29 fetuses and later developmental stages, 2) the activity state of the paternal Gpd gene is not fixed during early embryonic development in this species, 3) maior changes in paternal Gpd expression occur in advanced developmental stages and comprise a maturation of the gene expression pattern during ontogeny, and 4) alterations of paternal Gpd allele activity during development occur in a tissue-specific manner. © 1995 Wiley-Liss, Inc.     

Ethnic differences in mortality from sudden infant death syndrome in New Zealand.

OBJECTIVES--To examine the factors which might explain the higher mortality from sudden infant death syndrome in Maori infants (7.4/1000 live births in 1986 compared with 3.6 in non-Maori children). DESIGN--A large nationwide case control study. SETTING--New Zealand. 485 infants who died of sudden infant death syndrome were compared with 1800 control infants. There were 229 Maori and 240 non-Maori cases of sudden infant death syndrome (16 cases unassigned) and 353 Maori and 1410 non-Maori controls (37 unassigned). RESULTS--Maori infants had 3.81 times the risk (95% confidence interval 3.06 to 4.76) of sudden infant death syndrome compared with non-Maori infants. The risk factors for sudden infant death syndrome within groups were remarkably similar. When Maori and non-Maori controls were compared the prevalence of many of the known risk factors was higher in Maori infants. In particular, mothers were socioeconomically disadvantaged, younger, and more likely to smoke and their infants were of lower birth weight and more likely to share a bed with another person. Multivariate analysis controlling for potential confounders found that simply being Maori increased the risk of sudden infant death syndrome by only 1.37 (95% CI = 0.95 to 2.01), not statistically significantly different from 1. Population attributable risk was calculated for prone sleeping position, maternal smoking, not breast feeding, and infants sharing a bed with another person. In total these four risk factors accounted for 89% of deaths from sudden infant death syndrome in Maori infants and 79% in non-Maori infants. CONCLUSION--The high rate of sudden infant death syndrome among Maori infants is based largely on the high prevalence in the Maori population of the major risk factors. Other risk factors, not related to ethnicity, probably explain remaining differences between Maori and non-Maori children.     

Survival of 1476 patients initially resuscitated from out of hospital cardiac arrest.

OBJECTIVES--To determine the short and long term outcome of patients admitted to hospital after initially successful resuscitation from cardiac arrest out of hospital. DESIGN--Review of ambulance and hospital records. Follow up of mortality by "flagging" with the registrar general. Cox proportional hazards analysis of predictors of mortality in patients discharged alive from hospital. SETTING--Scottish Ambulance Service and acute hospitals throughout Scotland. SUBJECTS--1476 patients admitted to a hospital ward, of whom 680 (46%) were discharged alive. MAIN OUTCOME MEASURES--Survival to hospital discharge, neurological status at discharge, time to death, and cause of death after discharge. RESULTS--The median duration of hospital stay was 10 days (interquartile range 8-15) in patients discharged alive and 1 (1-4) day in those dying in hospital. Neurological status at discharge in survivors was normal or mildly impaired in 605 (89%), moderately impaired in 58 (8.5%), and severely impaired in 13 (2%); one patient was comatose. Direct discharge to home occurred in 622 (91%) cases. The 680 discharged survivors were followed up for a median of 25 (range 0-68) months. There were 176 deaths, of which 81 were sudden cardiac deaths, 55 were non-sudden cardiac deaths, and 40 were due to other causes. The product limit estimate of 4 year survival after discharge was 68%. The independent predictors of mortality on follow up were increased age, treatment for heart failure, and cardiac arrest not due to definite myocardial infarction. CONCLUSION--About 40% of initial survivors of resuscitation out of hospital are discharged home without major neurological disability. Patients at high risk of subsequent cardiac death can be identified and may benefit from further cardiological evaluation.     

Selenoprotein P associates with endothelial cells in rat tissues

 Selenoprotein P is an extracellular heparin-binding protein that has been implicated in protecting the liver against oxidant injury. Its location in liver, kidney, and brain was determined by conventional immunohistochemistry and confocal microscopy using a polyclonal antiserum. Selenoprotein P is associated with endothelial cells in the liver and is more abundant in central regions than in portal regions. It is also present in kidney glomeruli associated with capillary endothelial cells. Staining of selenoprotein P in the brain is also confined to vascular endothelial cells. The heparin-binding properties of selenoprotein P could be the basis for its binding to tissue. Its localization to the vicinity of endothelial cells is potentially relevant to its oxidant defense function. Accepted: 6 March 1997     

Determination of Effective Transport Coefficients for Bacterial Migration in Sand Columns

A well-characterized experimental system was designed to evaluate the effect of porous media on macroscopic transport coefficients which are used to characterize the migration of bacterial populations. Bacterial density profiles of Pseudomonas putida PRS2000 were determined in the presence and absence of a chemical attractant (3-chlorobenzoate) gradient within sand columns having a narrow distribution of particle diameters. These experimental profiles were compared with theoretical predictions to evaluate the macroscopic transport coefficients. The effective random motility coefficient, used to quantify migration due to a random process in a porous medium, decreased nearly 20-fold as grain size in the columns decreased from 800 to 80 (mu)m. The effective random motility coefficient (mu)(infeff) was related to the random motility coefficient (mu), measured in a bulk aqueous system, according to (mu)(infeff) = ((epsilon)/(tau))(mu) with porosity (epsilon) and tortuosity (tau). Over the times and distances examined in these experiments, bacterial density profiles were unaffected by the presence of an attractant gradient. Theoretical profiles with the aqueous phase value of the chemotactic sensitivity coefficient (used to quantify migration due to a directed process) were consistent with this result and suggested that any chemotactic effect on bacterial migration was below the detection limits of our assay.     

Characterization of midgut proteinase activities of white grubs: Lepidiota noxia,Lepidiota negatoria,and Antitrogus consanguineus (scarabaeidae,melolonthini)

The proteinases in the midguts of three scarab white grub species, Lepidiota noxia, L. negatoria, and Antitrogus consanguineus, were investigated to classify the proteinases present and to determine the most effective proteinase inhibitor for potential use as an insect control agent. pH activity profiles indicated the presence of serine proteinases and the absence of cysteine proteinases. This was confirmed by the lack of inhibition by specific cysteine proteinase inhibitors. Trypsin, chymotrypsin, elastase, and leucine aminopeptidase activities were detected by using specific synthetic substrates. A screen of 32 proteinase inhibitors produced 9 inhibitors of trypsin, chymotrypsin, and elastase which reduced proteolytic activity by greater than 75%. © 1995 Wiley-Liss, Inc.