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Biomedical subjects

D A Cooper

Publications and source records attributed to D A Cooper.

At least 271 records · Page 15Linked to original sources
PubMed1988

Hydrolysis of cis and trans isomers of retinyl palmitate by retinyl ester hydrolase of pig liver.

Relative retinyl ester hydrolase activities of pig liver homogenates (n = 4) toward 9,13-cis-, 13-cis-, 9-cis-, and all-trans-retinyl palmitate were 6.8 +/- 0.5 (SE), 5.7 +/- 0.5, 2.4 +/- 0.1, and 1, respectively. The range of apparent Km values for the four isomers was 142 to 268 microM, and the pH optima were 8-9 in all cases. Peak activities of retinyl ester hydrolase activities in pig liver cytosol toward 13-cis- and all-trans-retinyl palmitate were found in the 20 to 40% and in the 60 to 80% saturated ammonium sulfate (AS) fractions, respectively. By use of size-exclusion chromatography in 2 M KCl, hydrolase activity eluted at volumes corresponding to greater than 2000, 180, and 15 kDa from the 20-40% AS fraction, and at 180 kDa from the 60-80% AS fraction. On the basis of molecular size, different substrate specificities, detergent effects, and susceptibilities to inhibition by phenylmethylsulfonyl fluoride, we conclude that at least three distinct retinyl ester hydrolases are present in pig liver cytosol.

Ammonium Sulfate↗
PubMed1988

Resolution of amyloidosis (AA type) complicating chronic ulcerative colitis.

A 36-yr-old woman was admitted for the investigation of diarrhea, fever, weight loss, and a recurrent painful, red eruption on her forearms. She was found to have total colonic involvement with a nonspecific ulcerative colitis. Vascular and extravascular amyloid (AA type) was present in biopsy specimens of the colon, duodenum, and stomach. There was clinical and radiographic evidence of splenic and hepatic amyloidosis. Moreover, the presence of extravascular colonic amyloid, the absence of renal involvement, the relatively early detection of amyloid, and the resolution of amyloid after treatment make this case unique.

Adult↗
PubMed1988

Characterization of T lymphocyte responses during primary infection with human immunodeficiency virus.

The present study was undertaken to determine T cell response to primary human immunodeficiency virus (HIV) infection. No significant difference in T cell subsets was found between subjects who later seroconverted and a group of controls. Six subjects had multiple enumerations of T cell subsets done at the time of seroconversion. Initially, total lymphocyte and T cell subset counts were reduced. An inversion of the CD4+:CD8+ ratio due to a rise in the level of CD8+ cells was found later, followed by an appreciable increase in the number of CD8+ cells and further inversion of the CD4+:CD8+ ratio. Finally, the CD8+ cell count returned toward normal but remained higher than the CD4+ cell count; the inverted ratio was maintained. Lymphocyte hyporesponsiveness to mitogens and antigens was found during the seroconversion illness in one subject. In three of five subjects for whom data were available, an increase in the absolute number of CD8+ cells followed a decrease in the serum HIV antigen level.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Prevalence of antibodies to Epstein-Barr virus nuclear antigen 2B in persons infected with the human immunodeficiency virus.

We measured the presence of antibodies to the Epstein-Barr virus (EBV) nuclear antigen 2B (EBNA2B) in patients with AIDS and related disorders, persons with human immunodeficiency virus (HIV) infection, persons at risk for HIV infection, and normal persons. Sera from 38% (16 of 43) of the patients with AIDS and 35% (43 of 123) of HIV-positive individuals reacted with EBNA2B, versus 25% (21 of 83) of the high-risk patients and 7.5% (5 of 65) of the normal persons. Screening these sera against cell lines that express EBNA2B, EBNA2A, or neither antigen revealed that only a proportion of these sera contained EBNA2B-specific antibodies. Many sera reacted with both antigens. Of the EBNA2B-specific sera, 14% (6 of 43) were from patients with AIDS, 16% (20 of 123) from HIV-positive individuals, 5% (4 of 83) from high-risk individuals, and 4.5% (3 of 65) from normal persons. The presence of antibodies to the EBNA2B in HIV-infected individuals indicates that they may be infected with type B strains of EBV.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Gastrointestinal viral infections in homosexual men who were symptomatic and seropositive for human immunodeficiency virus.

Gastrointestinal viruses, predominantly rotaviruses and adenoviruses, were detected by enzyme-linked immunosorbent assay, electron microscopy, or cell culture in greater than 50% of two groups of homosexual men with symptomatic human immunodeficiency virus (HIV) infection, who did (54%) or did not (50%) have diarrhea. Lower detection rates were observed in HIV-seronegative (15%) and asymptomatic HIV-seropositive (16%) men. In the patients with diarrhea, 95% of the isolates of virus were found in the most immunosuppressed patients, those patients with AIDS-related complex or opportunistic infections associated with AIDS. High excretion rates of these viruses are probably associated with both anal-oral transmission and immunosuppression. These viruses apparently cause acute episodes or relapses of diarrhea in some patients but may be co-pathogens or noncontributory to chronic diarrhea in others.

AIDS-Related Complex↗
PubMed1988

Syringe HIV seroprevalence and behavioural and demographic characteristics of intravenous drug users in Sydney, Australia, 1987.

The contents of needles and syringes returned by intravenous drug users to two Sydney needle and syringe exchange centres were analysed for HIV antibodies by the enzyme-linked immunosorbent assay (ELISA). Reactive and borderline samples were further tested by the Western blot method. Basic demographic and needle sharing data were also collected from the clients of the exchanges. Of a sample of 1544 returned syringes, 48 (3%) were confirmed as containing HIV-infected blood. The proportion of infected syringes at exchange 2 was 6% (33 out of 545), which was significantly greater (P less than 0.05) than the proportion of exchange 1 at 1.5% (15 out of 999). The difference in seroprevalence between the two centres may be related to the behavioural characteristics of the client populations that attended each of the exchanges. The maintenance of a low syringe HIV seroprevalence (1-1.5%) over a 7-month period at one exchange may indicate that the availability of sterile needles and syringes prevented transmission of HIV among the clients of that exchange. HIV antibody testing of the contents of used syringes is a potentially valuable method of monitoring HIV infection among intravenous drug users. In this study, syringe exchange schemes have proved to be suitable venues for investigating the demographic characteristics and risk-taking behaviours of this population.

Adult↗
PubMed1988

The Sydney AIDS Project: development of acquired immunodeficiency syndrome in a group of HIV seropositive homosexual men.

The Sydney AIDS Project is a prospective immunoepidemiological study of 996 homosexual/bisexual men enrolled between February 1984 and January 1985. By January 1987, 32 of 386 homosexual men who were seropositive at enrollment in the study had developed AIDS, yielding a crude progression rate of between 2.8% and 4.2% per annum. Of these subjects, 23 (72%) developed AIDS within 12 months of enrollment. In univariate analysis, the only lifestyle differences between seropositive subjects who progressed to AIDS and those that did not progress were less frequent oral sex activity and more use of marijuana in the three months prior to enrollment. In multivariate analysis, seropositive subjects who progressed to AIDS were more likely to have a lower percentage of CD4+ cells, a higher percentage of CD8+ cells and to have used marijuana in the three months prior to enrollment than the seropositive subjects who did not progress. No HIV seropositive subject who was asymptomatic and had normal T-cell subsets at enrollment had developed AIDS by January 1987. Persistent generalised lymphadenopathy was not associated with progression to AIDS. Although there are a number of lifestyle factors that may be associated with HIV infection, this study did not implicate most of these in the progression of HIV seropositive subjects to end-stage AIDS. We conclude that antecedent changes in T-cell subsets are associated with progression to AIDS and we emphasise the prognostic value of enumeration of T-cell subsets in HIV seropositive persons.

Acquired Immunodeficiency Syndrome↗
PubMed1988

HIV infection associated with symptoms indistinguishable from functional psychosis.

Patients with acquired immunodeficiency syndrome (AIDS), who present with or develop psychotic symptoms, almost invariably have evidence of cognitive impairment. Three psychotic patients, one with AIDS, and two with AIDS-related complex (ARC), who showed no evidence of cognitive impairment, are reported. It is suggested that the human immunodeficiency virus (HIV) may produce symptoms indistinguishable from those seen in the functional psychoses.

AIDS-Related Complex↗
PubMed1988

Primary human immunodeficiency virus infection. Clinical and serologic aspects.

The identification of characteristic clinical, serologic, and immunologic responses to primary HIV infection has contributed greatly to our understanding of the natural history of HIV infection. Subjects usually present with a mononucleosis-like illness and during the period of primary infection there is a characteristic four-phase T cell response. Early serologic findings of infection include IgM antibody and free HIV p24 antigen. Tests for mononucleosis yield negative results, but atypical lymphocytosis may be present. We believe there are three primary goals for future research into primary HIV infection: to further define the features of this phase of infection, to develop early intervention strategies effective against HIV, and to further develop and foster education strategies that will prevent primary HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Capillary gas chromatographic-electron capture detection of coca-leaf-related impurities in illicit cocaine: 2,4-diphenylcyclobutane-1,3-dicarboxylic acids, 1,4-diphenylcyclobutane-2,3-dicarboxylic acids and their alkaloidal precursors, the truxillines.

A method has been developed that allows for the detection of the eleven stereoisomers of diphenylcyclobutanedicarboxylic acid in illicit cocaine samples, including alpha-, gamma-, and epsilon-truxillic acids and beta- and delta-truxinic acids. These, and other carboxylic acids, were also detected as ester moieties of alkaloidal impurities in illicit cocaine as well as in alkaloids of the South American coca leaf, e.g., alpha- and beta-truxilline. After lithium aluminum hydride reduction of the acidic and basic extracts of a prepared sample, the reduced species were derivatized with heptafluorobutyric anhydride in the presence of pyridine. The heptafluorobutyryl derivatives of the reduced diphenylcyclobutanedicarboxylic compounds were easily detected on-column at low picogram levels using a moderately polar fused-silica capillary column in the splitless mode and interfaced with a 63Ni electron-capture detector.

Alcohols↗
PubMed1987

The costs of hospital-based medical care for patients with the acquired immunodeficiency syndrome.

The costs which were incurred by patients for hospital-based care during the time from the diagnosis of the acquired immunodeficiency syndrome (AIDS) to death, range from pounds 6838 in London, England, to US$147,000 in Atlanta, USA. In 1986, a study was undertaken in Sydney to calculate the costs of the hospital-based treatment of patients with AIDS. The medical records of 39 patients who had received all their treatment at one institution were analysed retrospectively, and data were collected on their survival, hospitalizations, investigations and treatments. The mean survival time of the 39 patients was 7.2 months; during this time they had a mean of 4.0 hospital admissions that accounted for an average total stay of 34.6 days. In addition, they made, on average, 9.4 outpatient visits. There was a significant difference in the duration of hospitalization between those who presented with an opportunistic infection and those who presented with a malignancy (38.3 days and 22.4 days, respectively; P = 0.01). The mean cost for hospital-based care was $A22,332 (range, $A4229-$A58,398), of which 95% of costs were incurred for inpatient care. The mean cost of care of those who presented with an opportunistic infection was significantly higher than that of those who presented with a malignancy, but there was no difference according to the age at the time of diagnosis. If the predictions of 3000 cases of AIDS in Australia by 1991 are realized, such cases will represent--conservatively--an additional cost to the community of $A58.5 million. This study emphasizes the need for health authorities to plan for the future financial impact of the hospital-based treatment of patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Antibodies to the human immunodeficiency virus in needles and syringes used by intravenous drug abusers.

The sharing of needles and syringes by intravenous drug abusers has been recognized as a critical factor in the transmission of the human immunodeficiency virus (HIV). In an attempt to reduce the sharing of needles and syringes among intravenous drug abusers, a pilot sterile needle-and-syringe exchange programme was established in an inner city neighbourhood in Sydney. The contents of exchanged syringes were screened for antibody to HIV by the enzyme-linked immunosorbent assay (ELISA); reactive and borderline samples were tested further by the Western Blot method. Of a sample of 300 needles-and-syringes that were exchanged, three (1%) needles-and-syringes were confirmed as containing antibody-seropositive blood by both ELISA and Western Blot methods and thus as being potentially infectious. As only 70% of known positive-control syringes were detected in this study, the proportion of potentially infectious needles-and-syringes that was found may have underestimated the proportion of infectious injection equipment that was returned. These findings highlight the importance of the removal of used needles and syringes from circulation in addition to the supply of sterile equipment. This method of monitoring exchanged needles-and-syringes is suggested as a means to evaluate measures that are designed to reduce the transmission of HIV among intravenous drug abusers. The rapid implementation of sterile needle-and-syringe exchange programmes is imperative to stem the spread of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Analysis of manufacturing by-products and impurities in illicit cocaine via high-performance liquid chromatography and photodiode array detection.

An high-performance liquid chromatography (HPLC) method is reported for the detection of manufacturing by-products and impurities in illicitly produced cocaine. For the first time peak enriched chromatograms were obtained using HPLC, and were accomplished using reversed-phase chromatography and photodiode array detection. The use of sodium dodecylsulfate as an ion-pairing reagent permitted the simultaneous separation of acids, mono-protic amines and di-protic amines, and, in combination with gradient elution, greatly increased the number of compounds separated. A mixed binary-ternary gradient was used to further optimize the separation. Dual UV detection at 215 and 277 nm was used. The chromatogram at 215 nm consisted first of carboxylic acids such as benzoic acid, cinnamic acid (cis and trans) and several isomers of truxillic and truxinic acid; next the mono-protic amines benzoylecgonine and cinnamoylcocaine (cis and trans); and last a group of compounds which are believed to be isomers of the di-protic amine truxilline. In addition, simultaneous detection at 277 nm permitted the selective detection of various compounds, some of which are additional components. The rapid acquisition of UV spectra greatly facilitated compound identification.

Chromatography, High Pressure Liquid↗