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Biomedical subjects

J Gill

Publications and source records attributed to J Gill.

At least 91 records · Page 5Linked to original sources
PubMed1994

HIV-1 gp120/160 expressing transfected cell clones to evaluate the antibody-dependent cellular cytotoxicity (ADCC) during the course of HIV-1 infection.

Transfection by electroporation of the CEM.NKR cell line with a plasmid containing the HIVNL43 gp160 gene resulted in the establishment of HIV-1 gp120/160 expressing CEM.NKR cell clones. The cell-surface expression of the recombinant viral envelope is stable and does not lead to syncytium formation among a substantial number of cells expressing envelope glycoprotein, suggesting that these cells are suitable as targets to monitor HIV-specific ADCC activities with the stage or the progression of HIV-1 disease. By using these cells, the ability of sera from HIV-1 seropositive individuals to mediate ADCC against HIV-1 gp120/160 transfected cells in an antigen-specific manner was established. Approximately 63% of the HIV-infected individuals representing all stages of infection have virus-specific ADCC antibodies. Moreover, sera from healthy seropositive (CDC class II) subjects mediated substantially higher levels of ADCC activity (25.7 +/- 11.5%) than did sera from individuals in CDC class III (10.3 +/- 8.9%) or IVC1 (6.4 +/- 8.1%). The mean ADCC activity for the sera from the seronegative volunteers was 2 +/- 1.3%. The correlation between the ADCC level and CD4 cell depletion remains uncertain. Therefore, the established transfected cell line may be used to probe the role of gp120/160-specific ADCC activity in the development of AIDS and may also prove useful in screening human and murine monoclonal antibodies with potential ADCC activity. Such monoclonals may be useful for future immunotherapeutic agents in conjunction with antiviral chemotherapy.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1994

Radiology workload--a solution reviewed after 14 years' experience.

A method of controlling the radiological workload in a district general hospital, based on an estimation of the reasonable capacity of the department, was introduced in 1978. Measurement of the number of examinations performed compared with the estimated reasonable capacity shows that the method has been effective. An immediate 25% reduction in examinations was followed by a workload which varied between -4% and +16% of the capacity. An increase in the proportion of complex examinations in the period under review has been recognized. The method has encouraged referring doctors to exercise restraint and adopt guidelines, and helped persuade managers to increase capacity by appointing additional radiologists.

Appointments and Schedules↗
PubMed1994

Adrenoceptor-linked [45Ca2+] uptake in platelets from diabetic rats: a model for human platelets.

Adrenoceptor-linked 45 calcium uptake was investigated in platelet from diabetic rats (hyperglycaemic, streptozotocin-induced, of 60 days duration). Basal uptake was markedly enhanced in platelets from diabetic rats compared with controls. However, whereas adrenaline-stimulated uptake was unchanged, isoprenaline-stimulated uptake was significantly reduced and noradrenaline-stimulated uptake significantly increased. These latter data indicate that there are differential alterations of adrenoceptor subtypes in diabetes (i.e. an increase in alpha- but decrease in beta-adrenoceptors). These changes in calcium uptake and in adrenoceptor activity may relate to altered platelet function known to occur in experimental diabetes. Furthermore, the similarity of the rat platelet with that of the human (in terms of absolute calcium uptake, responses to agonists and changes in diabetes), renders the rat platelet an appropriate model for studying calcium dynamics and linked adrenoceptors in diabetes.

Animals↗
PubMed1994

Safety profile of didanosine among patients with advanced HIV disease who are intolerant to or deteriorate despite zidovudine therapy: results of the Canadian Open ddI Treatment Program.

The aim of this study was to ascertain the safety profile of didanosine (Videx; ddI) within the Canadian Open Treatment Program. Symptomatic HIV+ subjects with AIDS or ARC or CD4 < 200/mm3 were eligible to receive didanosine if they were either (a) intolerant to zidovudine (Retrovir, ZDV) or (b) deteriorating despite ZDV therapy. The dose of didanosine (powder formulation) was based on body weight as follows: > or = 75 kg, 375 mg b.i.d.; 50-74 kg, 250 mg b.i.d.; 35-49 kg, 167 mg b.i.d. Participants were monitored with physical examinations and prespecified laboratory studies by their treating physicians on a monthly basis. Follow-up data were collected in a central database through five regional coordinators. A total of 168 physicians across Canada participated in the program, and 825 subjects who started didanosine after July 1, 1990, were included in the analysis. Of these, 97% were male, 88% homosexual, and 59% had a prior diagnosis of AIDS. Reasons for enrolling was ZDV intolerance in 39%, failure in 25%, both in 32%, and other in 4%. Data were prospectively collected until July 31, 1991. Total follow-up was 3,440 patient-months and median follow-up was 4.3 months. A total of 78 deaths were reported, 44 of which occurred within a month after the last dose of didanosine. Causes of death included AIDS-related unspecified causes (13 patients), MAC (11), wasting (7), AIDS-related CNS involvement other than OI's (7), Kaposi's sarcoma (7), Pneumocystis carinii pneumonia (6), sudden death, including suicides and accidents (6), lymphoma (5), toxoplasmosis (4), cryptococcosis (4), cytomegalovirus (3), unspecified causes (2), tuberculosis (1), PML (1), and disseminated histoplasmosis (1). Didanosine was discontinued in 140 (17%) subjects during the study period due to adverse events.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Alcohol problems in employment: epidemiology and responses.

A review is presented of evidence related to the epidemiology of alcohol-related problems in employment and of policies to prevent or curb such problems. It is concluded that, although alcohol use is associated with accidents, absenteeism and inefficiency, epidemiological data from most countries are scarce. Available evidence is so limited that estimates of the extent or cost of alcohol-related problems in the workplace are of dubious value. National responses to alcohol problems in employment have been variable. A significant proportion of relevant published evidence relates to the U.S.A. It appears that even there very few workplace initiatives have been subjected to rigorous assessment. Limited evidence suggests that Employee Assistance Programmes for problem drinkers have reduced subsequent health-care costs.

Absenteeism↗
PubMed1993

Effect of milrinone on thromboxane A2 synthesis, cAMP phosphodiesterase and 45Ca2+ uptake by human platelets.

The phosphodiesterase inhibitors milrinone and isobutylmethylxanthine (IBMX) inhibited the conversion of [3H]cAMP to [3H]AMP by washed human platelets in concentration-dependent manners (IC50: milrinone, 2.6 x 10(-6) M; IBMX, 4.6 x 10(-6) M). Milrinone and IBMX increased cAMP levels when stimulated by a single concentration (0.3 microM) of iloprost. EC50:milrinone, 5.6 x 10(-5) M; IBMX, 3 x 10(-5) M. Milrinone was a potent inhibitor of platelet thromboxane A2 (TXA2) synthesis when stimulated by median stimulatory doses of collagen (IC50: 3 x 10(-7) M), sodium fluoride (NaF) (a non-specific G protein activator; IC50: 3 x 10(-7) M) and phorbol ester myristate acetate (PMA) (a protein kinase C activator; IC50: 2.2 x 10(-7) M). In contrast, at median stimulatory doses of A23187 and arachidonate there was a marked decrease in the potency of milrinone in inhibiting TXA2 synthesis. Milrinone had a weak inhibitory effect on TXA2 synthesis when elicited by freeze fracturing. In all experiments IBMX was a weaker inhibitor of TXA2 synthesis, although the general pattern of effects was similar to milrinone. Milrinone inhibited both collagen- and adrenaline-stimulated 45Ca2+ uptake by human platelets in dose-dependent manners. Since platelet TXA2 synthesis is dependent on Ca2+, and milrinone inhibited 45Ca2+ uptake, it is concluded that milrinone exerts its inhibitory effect on platelet activity, principally through an action on Ca2+ mobilisation/binding to effector proteins (protein kinase C and/or phospholipase A2).

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1993

A multicenter study of viral hepatitis in a United States hemophilic population.

Hemophilia A and B patients seen at nine US regional treatment centers were tested for serologic markers of hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis delta virus (HDV) during 1987 and 1988. Because human immunodeficiency virus (HIV) infection, a potentially confounding variable, was present in 53% of the group, the population was divided by HIV status for analysis purposes. In the HIV-positive group (N = 382), less than 1% had not been infected with HBV, HCV, or HDV, whereas 75% had evidence of infection with HBV and 98% with HCV. HBsAg, a marker of active HBV infection, was present in 12% of subjects; 96% of these were HCV positive. Anti-HDV was detected in 35 subjects (9.1%); all were anti-HBc positive. Ten of the 35 (29%) also were positive for IgM anti-HDV, indicating current infection. All 10 were HBsAg positive and 7 of the 9 tested were HDV RNA positive. Severe/moderate hemophilia B patients were more likely to have experienced an HBV infection and to be anti-HDV positive than were similar hemophilia A patients (22% v 8%, P < .05). In the HIV-negative group (N = 345), the subjects were younger and had less severe hemophilia than the HIV-positive patients. No evidence of HBV, HCV, or HDV infection was found in 18%, whereas 33% had experienced HBV infection and 79% were anti-HCV positive. Within this group, 4% were HBsAg positive. All 13 subjects with anti-HDV (4% of the HIV-negative group) also possessed anti-HBc. One (7.7%) was IgM anti-HDV positive and the serum from another contained HDV RNA. Both of these individuals were HBsAg positive. As in the HIV-positive group, severe/moderate hemophilia B patients were more likely to be HBV and HDV positive than were hemophilia A patients (9% v 3%, P < .05). A prevalence study of viral hepatitis in a large US hemophilic population showed that active infection with HCV is common, occurring in 89% of all study patients regardless of HIV status. Evidence of active HBV infection was found in 8%; 19% of these were actively infected with HDV. HDV was more common in hemophilia B patients after controlling for disease severity.

Adult↗
PubMed1993

Influence of recognition errors of computerised analysis of 24-hour electrocardiograms on the measurement of spectral components of heart rate variability.

Spectral methods for the assessment of heart rate variability (HRV) in 24-h electrocardiograms (ECG) are believed to require visual verification and manual editing of the computerised recognition of the ECG. This study investigated the effect of the recognition errors of computerised ECG recognition on two methods providing spectral HRV indices: (a) Fast Fourier Transformation (FFT); and (b) peak-to-trough analysis (PTA). Both methods were used to measure HRV spectra in 24-h ECGs recorded in 557 survivors of acute myocardial infarction. Each ECG was analysed using the Marquette 8000 Holter system and spectral HRV analyses were performed both prior to and after manual verification of the automatic ECG analysis. The FFT and PTA methods were used to calculate the low (0.04-0.15 Hz), medium (0.15-0.40 Hz) and high (0.40-1.00 Hz) HRV spectral components. For each method and for each spectral component, the rank correlations between the results obtained from unedited and edited ECG recognition were calculated. The correlations between the corresponding spectral components provided by the FFT and PTA methods applied to the edited recognitions were also calculated. Both methods were substantially affected by recognition errors. The FFT method was more sensitive to the misrecognition than the PTA method. The inter-method correlations were higher for the high and medium spectral components than for the low spectral component. The study suggests that spectral HRV analysis should be performed only on carefully verified and manually corrected recognitions of long-term electrocardiograms.

Adult↗
PubMed1993

Use of endoscopic biopsies and microelectrodes to study human gastric acid secretion in vitro.

We have investigated the possibility of measuring acid secretion from human gastric mucosa in vitro as a potential pharmacological preparation. We used open-ended 10 microns-tip, lix-based glass microelectrodes to measure the pH of the mucus layer of gastric biopsies superfused with a HEPES buffered solution in an organ bath. With no drugs added the pH of the mucus layer of biopsies from the body of the stomach stayed constant but the pH of antral biopsies fell slightly by a median of 0.12 pH units over 80 min (P < 0.05). Stimulation of the biopsies with 1-100 microM histamine produced a dose-dependent decrease in pH which was significantly greater in biopsies from the gastric body than from the antrum. 500 pM pentagastrin produced a median fall in pH of 1.20 (P < 0.01) which was prevented by the prior addition of 100 microM omeprazole or 10 microM ranitidine. Omeprazole or ranitidine alone produced slight rises in the median pH of 0.47 (P < 0.05) and 0.26 (P < 0.05) units respectively. Those biopsies which were infected with Helicobacter pylori had a slightly elevated initial pH of about 0.2 of a pH unit (P < 0.05). This novel system provides a means to study human gastric acid secretion in vitro and may be valuable in the testing of new drugs on the stomach.

Adolescent↗
PubMed1993

Influence of environmental factors on the deep and skin temperature in the European bison, Bison bonasus (L.).

1. In 43 European bison divided into three groups (Group A, 3-8-month-old calves; Group B, 18-month-7-year-old young bison; Group C, 12-24-year-old bison) the rectal, humerus region and abdomen region temperatures were measured. 2. The experiments were carried out in winter months, from mid-December to mid-March. 3. The mean rectal temperatures changed from 38.55 degrees C in calves to 38.15 degrees C in the oldest bison. 4. The mean temperatures of the humerus region changed from 20.69 degrees C in calves to 21.49 degrees C in older bison. 5. The mean temperatures of the abdomen region changed from 20.79 degrees C in calves to 22.17 degrees C in older bison (Gr. B). 6. The cluster analysis divided the bison into four groups named hot, warm, cool and cold bison. 7. Only air temperature measured 2 m above the ground and snow cover influenced the integrated bison temperature. Age, sex and mass as well as some environmental factors had no influence. 8. Measurements made 1 to nearly 4 hr after a bison's death showed a drop in rectal temperature and mostly increases in temperatures of the humerus and abdomen regions.

Aging↗
PubMed1993

Effect of buflomedil on in vitro prostacyclin and endothelin synthesis by vascular (rat and human) and penile (rat) tissue and calcium uptake by isolated human platelets.

The effect of buflomedil, a vasodilator, on: (a) in vitro prostacyclin (PGI2) synthesis by the rat aorta and penis, human cultured endothelial cells (HUVECs) and human iliac artery, (b) endothelin synthesis by HUVECs and (c) 45Ca2+ uptake by isolated human platelets was investigated. Buflomedil had no effect on PGI2 synthesis by rat aorta, iliac artery or HUVECs (short or long-term incubations). However, buflomedil inhibited noradrenaline- (but not arachidonate- or ionophore A23187-) stimulated PGI2 synthesis. Buflomedil had a weak stimulatory effect on PGI2 synthesis by the isolated rat penis, but this was not inhibited by cholinergic antagonists. Buflomedil (except at supra-therapeutic concentrations) exerted no effect on endothelin release by HUVECS. Buflomedil inhibited 45Ca2+ uptake by human platelets when stimulated with collagen and adrenaline, but not when stimulated with calcium ionophore A23187. These data demonstrate that buflomedil has no deleterious effect on the enzymes that control vascular PGI2 synthesis. The data also adds to the evidence that buflomedil is an alpha-adrenoceptor blocker and has stimulatory effects on penile PGI2 synthesis. Both of these properties may prove useful in the treatment of impotence. The specific inhibition of 45Ca2+ uptake consolidates that buflomedil has some calcium-channel-blocking properties which may explain, at least in part, its vasodilator and antiplatelet properties. Buflomedil may prove beneficial in the treatment of impotence via three mechanisms: (a) stimulation of penile PGI2 synthesis (b) alpha-adrenoceptor blockade and (c) calcium-mobilization-blocking properties.

Animals↗
PubMed1992

Bacterial toxin superantigens activate human T lymphocytes reactive with myelin autoantigens.

Some bacteria that are common human pathogens produce protein toxins that are potent activators of human T lymphocytes expressing certain types of T-cell receptors. In this study we examined the ability of staphylococcal toxins to stimulate human T lymphocytes that also recognized the myelin autoantigens myelin basic protein and proteolipid protein. T-cell populations responding to myelin basic protein or proteolipid protein were isolated from 4 subjects including 1 individual with multiple sclerosis. All myelin antigen-specific T cells responded in proliferation studies to at least one of the nine superantigenic toxins used in this study. The superantigenic toxins were up to 7 x 10(5)-fold more potent in proliferation assays than the myelin antigens to which the T cells were initially sensitized. In addition, cytotoxic, myelin basic protein-reactive T lymphocytes lysed antigen-presenting cells incubated with superantigenic toxins. These findings demonstrate a mechanism by which some bacterial infections might produce activation of myelin basic protein- and proteolipid protein-reactive T lymphocytes and perhaps contribute to demyelinating disease in humans.

Antigens, Bacterial↗
PubMed1992

Elements of acid-base balance in the European bison, Bison bonasus (L.) in the winter period.

1. In the blood of 65 European bison divided into four groups (Group 1, 0-3-year-old males; Group 2, 0-3-year-old females; Group 3, mature bulls, over 3 years old; Group 4, mature cows, over 3 years old) the values of pH, pCO2, pO2, base excess and bicarbonate level were studied. 2. The studies were carried out in winter months, from mid-December to mid-April. 3. No significant differences in parameters studied were found between young males and females. 4. All indices found in mature bulls and cows showed significant differences between all other groups. 5. Most of parameters examined here in European bison are comparable with those found in other big ruminants.

Acidosis↗