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Biomedical subjects

A Hay

Publications and source records attributed to A Hay.

At least 19 recordsLinked to original sources
PubMed1992

Scientific discourse, in public.

The experience of writing for a wider audience has benefits and drawbacks. Attempting to make scientific issues more accessible to non-scientists is no easier than explaining them to peers. Indeed, explaining toxicological data such as solvent measurements from a hazardous waste site can be even more difficult, especially in addressing those living next to the site. Alastair Hay reconsiders his experience in two cases that brought toxicology under public scrutiny.

Chemical Industry↗
PubMed1992

Effect of metals on interleukin-6 (IL-6) mitogenic stimulation of murine hybridoma cells.

The effect of several divalent metal cations (Co, Cu, Zn, Hg and Pb) on the proliferative response of B9 hybridoma cells to IL-6 has been investigated. At concentrations which are not cytotoxic all the metals inhibited proliferation. The inhibition by Cd and Pb was dependent on both time of addition of the metal and IL-6 concentration. Cd (10 microM) and Pb (50 microM) added at the same time as IL-6 were inhibitory but added 24h later had no effect. Increasing the concentration of IL-6 overcame the inhibitory effect of Cd (10 microM) and Pb (50 microM). Inhibition caused by the other metals was independent of either time of addition or IL-6 concentration. IL-6 did not stimulate an increased intracellular concentration of metallothionein suggesting that the protective effect of IL-6 is not mediated via induction of metallothionein. The results suggest that there are at least two distinct metal sensitive events in B9 proliferation, i) IL-6 reversible inhibition by Cd and Pb ii) IL-6 independent inhibition by Co, Cu and Hg.

Animals↗
PubMed1991

Toxicity from ragwort and fat cow syndrome, or from industrial chemicals: the value of epidemiological analysis for interpreting clinico-pathological findings.

When livestock in close proximity to industries develop signs of ill-defined disease, toxic effects from industrial pollution should be considered in the differential diagnosis. In establishing the final diagnosis, epidemiological methods should be applied to supplement the clinical and pathological techniques. This viewpoint is illustrated by two case-histories describing episodes of cattle disease in central Scotland. A long-established and successful dairy herd in central Scotland sustained severe morbidity and mortality amongst animals which had grazed on a field beside a recently established dump which contained wastes from a chemical waste incinerator. An official investigation concluded that the episode of disease was the result of ragwort poisoning; this diagnosis was reached on clinical and pathological grounds only. A similarly unexpected and severe epidemic occurred a few years later in another dairy herd, about 1 km further away from that incinerator (which was also within 100 m of a municipal incinerator). The official investigation, which again focused on clinical and pathological criteria, led to the diagnosis of fat cow syndrome. In the first episode, contaminated water drained from the chemical waste dump on to the cows' field; in the second episode, the relevant field was affected by airborne pollution from the two waste incinerators mentioned earlier. In both episodes, the epidemiological features, which were not examined systematically by the original investigators, were consistent with the hypothesis that these episodes resulted from exposures to toxic contaminants.

Animals↗
PubMed1991

A recent assessment of cocoa and pesticides in Brazil: an unhealthy blend for plantation workers.

Cocoa is the major source of income for the Brazilian state of Bahia and some 2.3 million people rely on the crop for their livelihood. Most cocoa is grown on large plantations where working conditions are often extremely poor. Few workers using pesticides on plantations, or on small-holdings, have had instruction about safe working practices. Protective clothing is rarely available. The result is frequent complaints about health. None of this likely to improve in the short term given Brazil's perilous economic situation.

Agricultural Workers' Diseases↗
PubMed1991

Needle penetration of the globe during retrobulbar and peribulbar injections.

The charts of 23 patients with needle penetration of the globe during retrobulbar or peribulbar injections between January 1980 and May 1990 were reviewed. Possible needle penetration risk factors included high myopia, previous scleral buckling procedures, injection by nonophthalmologists, and poor patient cooperation during the injection. Of the 23 cases of ocular penetration, 16 (70%) were from sharp (22-, 23-, and 25-gauge) needles, and 7 (30%) were from blunt (23- and 25-gauge) needles. Management options depended on the severity of the intraocular injury. Retinal breaks without retinal detachment were treated by laser photocoagulation (four cases) or cryopexy (one case) and were observed in three cases. More advanced complications (retinal detachment and vitreous hemorrhage) were usually treated by pars plana vitrectomy with or without a scleral buckle (12 of 14 cases). The final visual acuity was 20/400 or better in only 2 of the 14 retinal detachment cases. In cases without retinal detachment, the final visual acuity was 20/50 or better in 7 of 9 cases.

Adult↗
PubMed1991

Measuring compliance in methadone maintenance patients: use of a pharmacologic indicator to "estimate" methadone plasma levels.

A quantitative indicator of compliance is not available for methadone--the drug of choice for the treatment of opioid addiction. We successfully used low-dose phenobarbital (a valid pharmacologic indicator) to measure compliance by incorporating the drug into the methadone medication of patients attending an addiction unit. Plasma phenobarbital and methadone concentrations were measured in 20 (11 clinic-based and 9 community-based) patients receiving long-term treatment with the phenobarbital level-to-dose ratio, together with interviews, to validate methadone measurements and to monitor compliance. Patients attending the unit on a daily basis and who consumed their medication in the clinic were substantially more compliant than community-based patients. Laboratory measurements of phenobarbital and methadone helped to identify the use of illicit methadone, as well as incorrect self-administration, such as the consumption of several days' dosage at one time.

Adult↗
PubMed1991

High-dose methadone and the need for drug measurements in plasma.

We report a case of high-dose methadone prescribed to a heroin addict for pain control. The patient was prescribed methadone during convalescence from surgery and subsequently for maintenance treatment. Dosing was started at 360 mg of methadone per day and reduced over 12 days to an 80 mg/day maintenance dose. Although the patient was drowsy on the initial dose, his recovery was uneventful. However, there were complaints of pain and withdrawal discomfort when the plasma concentration decreased to less than 1 mg/L. Measurements of methadone in plasma were helpful for monitoring the recovery of this patient after surgery and are likely to prove useful in similar cases.

Adult↗
PubMed1991

Methadone in saliva.

Explore the source record for details and available documents.

Chromatography, High Pressure Liquid↗
PubMed1990

Histological and immunohistochemical study of hepatitis B virus in human immunodeficiency virus infection.

Because the risk factors for human immunodeficiency virus (HIV) infection and hepatitis B (HBV) are similar and therefore coinfection is not uncommon, a detailed histological and immunohistochemical study of chronic hepatitis B infection in a group of 20 HIV positive Caucasian males (who did not have AIDS) and 30 HIV negative controls were undertaken. Using both the conventional histological classification and the Knodell histological activity index it was shown that HIV negative patients were more likely to have active disease and also more scarring than HIV positive patients. Hepatitis B surface antigen (HBsAg) expression was not significantly different between the two groups but expression of hepatitis Be antigen (HBeAg) and HBV-DNA polymerase was greater in those who were HIV positive. HIV positive patients are therefore more likely to have immunohistochemical markers of active viral replication, although histologically, liver disease is less severe. These findings have important implications for assessing the biopsy specimens in this group of patients and for treatment strategies aimed at improving their immune function.

Adult↗