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Biomedical subjects

J Armstrong

Publications and source records attributed to J Armstrong.

At least 109 records · Page 6Linked to original sources
PubMed1993

Effects of adoptive immunotherapy with autologous CD8+ T lymphocytes on immunologic parameters: lymphocyte subsets and cytotoxic activity.

CD8+ cytotoxic T lymphocytes (CTL) may be an important parameter of host resistance to HIV infection. The present study determined whether CD8+ cells could be purified and propagated in vitro to enhance anti-HIV CTL activity, and the immunologic effects of infusion of these cells into autologous, HIV-infected patients as a potential immunotherapy for AIDS and AIDS-related complex (ARC). CD8+ lymphocytes from five AIDS and ARC patients were purified from leukapheresis preparations in cell culture flasks coated with CD8-specific monoclonal antibodies and propagated in vitro for 3 weeks. The ex vivo propagated cells were 98% (+/- 1%) CD8+ and 43% (+/- 6%) HLA-DR+. The majority of the CD8+ cell preparations had increased lytic activity against autologous B lymphoblastoid cells infected with vaccinia virus vectors expressing HIV-IIIb structural proteins gag, pol, or env, relative to that of fresh blood mononuclear cells tested prior to purification and culture. The results also show for the first time that CD8+ CTL from HIV-infected patients can lyse cells expressing the HIV regulatory protein, tat. Enhanced expression of CD56 (natural killer cell marker) and lytic activity against vaccinia virus control vector-infected, autologous targets were also noted in the CD8+ cell preparations. Infusion of the CD8+ CTL into autologous patients was well-tolerated and resulted in low but discernible, temporal increases in circulating cytotoxic activity against the HIV gene-expressing targets.

AIDS-Related Complex↗
PubMed1993

Enhanced expression of human immunodeficiency virus type 1 correlates with development of AIDS.

The progression to AIDS may be significantly related to the level of human immunodeficiency virus type 1 (HIV-1) replication. We have used quantitative cell culture and quantitative DNA and RNA PCR to measure viral load and expression in peripheral blood mononuclear cells obtained cross-sectionally and longitudinally from HIV-1-seropositive homosexual men enrolled in the Multicenter AIDS Cohort Study. Our results indicate that the number of circulating CD4+ T-lymphocytes producing HIV-1 increased as the total number of CD4+ T-cells declined. However, there was no correlation between the number of HIV-1-producing CD4+ cells and the duration of infection. Furthermore, the level of HIV-1 gag RNA increased as the disease progressed and CD4+ cell numbers declined. Subjects who remained asymptomatic with stable CD4+ cell counts, however, maintained a very low level of HIV-1 RNA expression during the entire period of follow-up (38-71 months). In contrast to viral RNA expression, the level of proviral DNA did not change significantly as the disease progressed. However, the level of proviral DNA was significantly higher in AIDS patients than in men who remained asymptomatic. Such increased levels of HIV-1 DNA were detected 34-68 months before the development of AIDS. These results support the role of HIV-1 RNA expression in the development of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1993

An ethopharmacological analysis of the behavioral effects of 8-OH-DPAT.

Several behaviors associated with the serotonin syndrome have been reported in rats following administration of the 5-HT1A receptor agonist 8-OH-DPAT. The present investigation approached this phenomenon from an ethopharmacological perspective, and provided a detailed temporal analysis of the behavioral effects of this compound over a 2-h period, in both male and female rats in the home cage. In addition, in order to further characterize the nature of the forepaw-treading and locomotor elements, and assess the extent of influence of the physical characteristics of the test arena, this study provided a detailed analysis of these behaviors in both the home cage and a large oval runway. In the initial analysis, the data indicate a distinct chronological sequence of effects following 8-OH-DPAT treatment. For example, "flat back" activity and lower lip retraction were apparent within a few minutes post-injection, the former dissipating after about 30 min and being replaced as the prepotent response by a more general (curved back) locomotor enhancement, while the latter effect remained throughout the 2-h test period. Interestingly, there were reliable gender differences in terms of the onset and disappearance of several behavioral components, with females generally being more rapidly affected, but recovering earlier than males. The detailed analysis of locomotor activity and forepaw treading would suggest that the locomotor syndrome primarily involves forward movement, heavily guided by the physical environment. Furthermore, forepaw-treading would seem only to occur when an animal reaches a barrier and forward movement is briefly interrupted, as no reliable incidence of this behavior was observed in the open area of the test area. Together, these findings provide further characterization of the behavioral syndrome induced by 8-OH-DPAT, and indicate the importance of time post-administration, gender of the subject, and the physical characteristics of the test environment, when considering stereotypical drug effects.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1993

Biochemical responses of broiler chicks to folate deficiency.

The effects of folate sufficiency and deficiency in three pathways of folate metabolism were studied in 2-and 3-week-old broiler chicks. Erythrocyte phosphoribosylpyrophosphate concentrations and dihydrofolate reductase (EC 1.5.1.3) activity were significantly elevated in folate deficiency. Percentage incorporation of deoxyuridine into bone marrow DNA was reduced in folate deficiency. There was a trend towards reduced liver dihydrofolate reductase activity in deficient chicks. These studies identify further biochemical criteria that can be used to assess folate status of chicks.

Animals↗
PubMed1993

Function of the ypt2 gene in the exocytic pathway of Schizosaccharomyces pombe.

The ypt2 gene of the fission yeast Schizosaccharomyces pombe encodes a member of the ypt/rab family of small GTP-binding proteins, related in sequence to Sec4p of Saccharomyces cerevisiae but closer to mammalian rab8. We have introduced a mutation into the gene corresponding to a mutation identified in ypt1, in which a conserved valine residue was altered to asparagine. The mutated ypt2 gene was introduced into the S. pombe genome by gene replacement. The resulting strain was temperature-sensitive for growth. Normal growth was restored by introduction of a plasmid-borne wild-type ypt2 cDNA or by cDNA for rab8 but not by various other rab or ypt sequences. At restrictive temperature the mutant cells accumulated the secretory protein acid phosphatase in a form that appeared to be fully glycosylated and acquired a population of vesicles detectable by electron microscopy. Thus the ypt2 protein, and by inference rab8, appear to function in the last stage of the secretory pathway.

Acid Phosphatase↗
PubMed1993

Schizosaccharomyces pombe ypt5: a homologue of the rab5 endosome fusion regulator.

The ypt/rab proteins are a family of small GTP-binding proteins thought to be required for different stages of membrane traffic. From the fission yeast Schizosaccharomyces pombe we have isolated and characterized ypt5, a gene encoding a homologue of rab5, a mammalian protein apparently involved in regulating fusion of early endosomes. Recombinant ypt5 protein bound GTP. The ypt5 gene was found to be essential for viability on minimal media, but ypt5-disrupted cells grew slowly on some rich media and accumulated a population of small vesicles not observed in wild-type cells. Canine rab5 cDNA could replace the ypt5 gene in S. pombe and restore normal growth and viability. Ypt5 protein expressed in mammalian cells colocalized with the transferrin receptor to early endosomes. Thus, molecular aspects of the early endocytic pathway may be conserved between mammalian cells and S. pombe and hence may be amenable to genetic analysis.

Amino Acid Sequence↗
PubMed1993

The effect of essential fatty acids on epidermal atrophy due to topical steroids.

The effect of topical n-6 essential fatty acids in the form of evening primrose oil on the epidermal atrophy caused by a potent topical steroid was studied in 24 normal volunteers by measuring epidermal thickness and cross-sectional area and by histological examination. Epidermal thickness and cross-sectional area were significantly lower in normal forearm skin treated with 0.1% betamethasone valerate twice daily without occlusion for 3 weeks when compared with placebo-treated skin. The addition of evening primrose oil to the topical steroid did not prevent steroid-induced epidermal atrophy suggesting that steroid-induced epidermal atrophy is not mediated by the inhibition of essential fatty acid release from cell membranes.

Adult↗
PubMed1993

Public opinion regarding consent to treatment.

OBJECTIVE: To examine public opinion regarding certain elements of consent: disclosure, advance directives, substitute decisions, emergency treatment, and advocacy. DESIGN: Cross-sectional random-digit-dialing telephonic survey. SETTING: General public. PARTICIPANTS: One thousand randomly-selected adults living in Ontario. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Self-reported attitudes and behaviors. RESULTS: Of 5,708 telephone numbers drawn, 641 were non-valid or non-residential, 1,283 were not in service, 1,068 had no answer, a busy line, or an unavailable respondent, 147 subjects had a language barrier, 1,497 subjects refused, 72 interviews were incomplete, and 1,000 interviews were completed. With regard to disclosure, 33% of respondents said that a doctor should withhold information from a patient if asked to do so by the patient's family. With regard to advance directives, 36% of respondents had had advance discussions with their families, and 12% had completed a living will. With regard to substitute decisions, 77% of respondents said that they would went their wishes followed if they were unable to make medical decisions for themselves; 58% wanted their spouse or partner to make such decisions for them. With regard to emergency treatment, 48% of respondents stated that a doctor should give a life-saving blood transfusion to an unconscious adult carrying a card stating that blood transfusion was against his or her religious beliefs. With regard to advocacy, 78% of respondents supported mandatory advocacy services for serious health decisions such as whether to have heart surgery; 33% supported advocacy services for less serious decisions such as whether to have a dental filling. CONCLUSIONS: These data highlight the need to reconsider legislative provisions regarding and/or target public education programs toward specific consent-related issues including disclosure, advance directives, substitute decisions, emergency treatment, and advocacy.

Adult↗
PubMed1993

Operation Everest. II: Spirometric and radiographic changes in acclimatized humans at simulated high altitudes.

We report spirometry and radiographic data on eight normal male human subjects during prolonged graded altitude exposure to as high as 8,848 m above sea level in a hypobaric chamber. We found a significant and progressive drop in FVC by 14 +/- 3% over 40 days, which resolved slowly during the first 48 h after descent. With altitude, midrange forced expiratory flow (FEF25-75) increased by 82 +/- 3%, probably because of reduced air density. FEV1, however, did not change. Chest radiographs on subjects taken 2 h after descent to sea level showed a pattern of pulmonary artery enlargement and interstitial edema. These data suggest that increased pulmonary blood volume and edema may be causes of the restricted pulmonary function pattern.

Acclimatization↗
PubMed1993

The BiP protein and the endoplasmic reticulum of Schizosaccharomyces pombe: fate of the nuclear envelope during cell division.

A polyclonal antibody was raised to the C-terminal region of fission yeast BiP. The use of this antibody for immunoprecipitation, western blotting and immunofluorescence has confirmed and extended the observations made previously with an epitope-tagged BiP molecule. A fraction of BiP protein is glycosylated in Schizosaccharomyces pombe cells. Pulse-chase experiments showed that this modification occurs rapidly upon synthesis and that the extent of glycosylation does not then change with time. BiP protein is induced by elevated temperatures and by treatment with tunicamycin. The antibody cross-reacts with proteins of similar molecular weight in the yeasts Kluyveromyces lactis and Schizosaccharomyces japonicus. Immunofluorescence of BiP has been used to follow the behaviour of the ER and in particular the nuclear envelope through the cell cycle.

Amino Acid Sequence↗
PubMed1992

Post-translational processing of Schizosaccharomyces pombe YPT proteins.

ras proteins are post-translationally processed at their carboxyl-terminal CAAX motif by a triplet of modifications: prenylation of C with farnesyl, proteolytic trimming of AAX, and carboxyl-methylation. These modifications co-operate with palmitoylation of nearby sites or a polybasic region to target plasma membrane localization. The related YPT/rab proteins in contrast are localized to compartments of the endo-membrane system and may be involved in directing membrane traffic. These proteins end in XCC or CXC motifs. We have analyzed the processing of members of this subfamily form the fission yeast Schizosaccharomyces pombe. We find using in vitro translation in reticulocyte lysates that YPT1, -3, and -5 are prenylated with geranylgeranyl and that they incorporate label from [3H]mevalonic acid when expressed in transfected COS cells in vivo. Furthermore, prenylation was necessary for membrane binding in vivo. The CXC protein YPT5, but neither of the two XCC proteins YPT1 and YPT3, was carboxyl-methylated in S. pombe and in COS cells in vivo. However, YPT5 was not carboxyl-methylated in vitro in lysates which were able to methylate ras protein. YPT3 was detectably palmitoylated when expressed in COS cells, though at a much lower level than ras.

Amino Acid Sequence↗
PubMed1992

A homologue of the ras-related CDC42 gene from Schizosaccharomyces pombe.

A cDNA was isolated from the fission yeast, Schizosaccharomyces pombe, using mixed oligodeoxyribonucleotides encoding part of the GTP-binding site of the ras superfamily. The encoded protein is the homologue of the budding yeast CDC42 gene product and the human proteins, CDC42Hs and G25K.

Amino Acid Sequence↗
PubMed1992

Protein prenylation in Schizosaccharomyces pombe.

S. pombe is shown to be a powerful system for studies concerning attachment of polyisoprenoid moieties to proteins, due to its ability to take up exogenous mevalonic acid efficiently. The fission yeast can take up about 5% of the exogenously added mevalonic acid and incorporate approximately 10% of this into protein. By contrast, the uptake obtained with the budding yeast S. cerevisiae is less than 0.5%. HPLC analysis of total S. pombe protein-bound isoprenoids revealed that approximately 55% of the counts co-migrated with the geranylgeraniol standard, while approximately 45% of the counts co-migrated with farnesol. We could not detect any effects of mevinolin or other HMG-CoA reductase inhibitors in S. pombe.

Chromatography, High Pressure Liquid↗
PubMed1992

Analysis of the BiP gene and identification of an ER retention signal in Schizosaccharomyces pombe.

We have cloned the gene for the resident luminal ER protein BiP from the fission yeast, Schizosaccharomyces pombe. The predicted protein product is equally divergent from the budding yeast and mammalian homologues. Disruption of the BiP gene in S. pombe is lethal and BiP mRNA levels are regulated by a variety of stresses including heat shock. Immunofluorescence of cells expressing an epitope-tagged BiP protein show it to be localized to the nuclear envelope, around the cell periphery and in a reticular structure through the cytoplasm. Unexpectedly, we find the BiP protein contains an N-linked glycosylation site which can be utilized. The C-terminal four amino acids of BiP are Ala-Asp-Glu-Leu, a new variant of the XDEL sequence found at the C-termini of luminal endoplasmic reticulum proteins. To determine whether this sequence acts as a sorting signal in S.pombe we expressed an acid phosphatase fusion protein extended at its C-terminus with the amino acids ADEL. Analysis of the sorting of this fusion protein indicates that the ADEL sequence is sufficient to cause the retention of proteins in the endoplasmic reticulum. The sequences DDEL, HDEL and KDEL can also direct ER-retention of acid phosphatase in S.pombe.

Acid Phosphatase↗
PubMed1992

Oral rabies vaccination of skunks and foxes with a recombinant human adenovirus vaccine.

A new recombinant rabies vaccine (human adenovirus 5 containing the rabies glycoprotein gene) was given to striped skunks (Mephitis mephitis) and red foxes (Vulpes vulpes). Groups of skunks received the vaccine in baits, by direct instillation into the mouth, or intramuscularly. Foxes were given vaccine by direct instillation into the oral cavity (DIOC). Selected groups of vaccinated skunks and foxes were challenged with street rabies virus. There were high rates of seroconversion (generally with high antibody titers) in both foxes and skunks, with survival of all challenged vaccinated animals (all challenge controls developed rabies). In skunks, vaccine given DIOC was effective over a broad range of doses (10(8.7), 10(7.6) and 10(6.4) median tissue culture infective doses). There was no evidence of pathogenic effects. The results indicate that this adenovirus recombinant has considerable potential as a wildlife oral rabies vaccine.

Adenoviruses, Human↗
PubMed1992

Optic neuropathy and central nervous system disease associated with primary Sjögren's syndrome.

Three cases of optic neuropathy associated with primary Sjögren's syndrome are reported. All three patients had clinical manifestations of primary Sjögren's syndrome, although two of the patients did not report sicca symptoms at initial examination. Two patients had focal neurologic signs in addition to optic neuropathy. The differentiation of this syndrome of optic neuropathy, focal neurologic signs, and Sjögren's syndrome from multiple sclerosis and antiphospholipid antibody syndrome is important for reasons of treatment and prognosis. This diagnostic differentiation was facilitated by positive tests for xerophthalmia and findings of positive minor salivary gland biopsy. High titers of antinuclear antibody, anti-SSA(Ro), and anti-SSB(La), and the absence of antiphospholipid antibodies provided additional help in the differential diagnosis. In 5 years of observation, none of the patients developed symptoms of multiple sclerosis or additional connective tissue disorders.

Adult↗