PubMed Health⌕ Search

Biomedical subjects

J A Henry

Publications and source records attributed to J A Henry.

At least 19 recordsLinked to original sources
PubMed1992

Toxicity and deaths from 3,4-methylenedioxymethamphetamine ("ecstasy")

The risk of adverse reactions to 3,4-methylenedioxymethamphetamine (MDMA), more commonly known as "ecstasy", is now widely known in both the USA and UK, but the patterns of illness remain varied. We report our experience during 1990 and 1991. There has been a recent increase in cases of severe toxicity following recreational misuse of small amounts of MDMA. Among 7 fatalities, the pattern of toxicity included fulminant hyperthermia, convulsions, disseminated intravascular coagulation, rhabdomyolysis, and acute renal failure. Until now, there have been few reports of this type of toxicity from MDMA, which may be related both to the potential of the drug to alter thermoregulation and to the circumstances of misuse. In addition, we have monitored 7 cases of hepatotoxicity and suspect that the frequency of this complication is increasing; a history of MDMA misuse should be sought in young people presenting with unexplained jaundice or hepatomegaly. We also describe 5 subjects involved in road traffic accidents in whom MDMA was identified. Misuse of MDMA can have severe acute toxic effects; few data are available concerning long-term morbidity, and this deserves close monitoring in future.

3,4-Methylenedioxyamphetamine↗
PubMed1992

Retinoblastoma and p53 gene expression related to relapse and survival in human breast cancer: an immunohistochemical study.

Inactivation of tumour suppressor genes may be an important aetiological factor in many human cancers including breast. In a study of 197 breast cancer patients, tumour tissue was snap-frozen at the time of surgery and immunohistochemical labelling for p53 protein and retinoblastoma (Rb) gene product carried out using an indirect immunohistochemical technique. Tumours were scored by two independent observers for the intensity of nuclear staining for each antibody. Expression of p53 protein showed a significant association with a shorter time to relapse (P = 0.03) and death (P = 0.02) (log rank test). p53 expression did not correlate with nodal status but showed a significant association with high tumour grade (P = 0.001). Rb gene expression showed no relationship to relapse or survival but loss of expression showed a significant correlation with positive lymph node status. The manner by which these proteins might act to determine tumour behaviour remains to be established.

Breast Neoplasms↗
PubMed1992

Predicting outcome for patients with node negative breast cancer: a comparative study of the value of flow cytometry and cell image analysis for determination of DNA ploidy.

This study was aimed at determining whether tumour DNA content measured by cell image analysis could provide additional prognostic information when compared to that provided by flow cytometry. Sections cut from paraffin blocks of tumours from 101 patients with node negative breast cancer were analysed by both methods and the results related to other prognostic variables and to patient relapse and overall survival. DNA ploidy measured by flow cytometry classified 46 tumours as diploid and 55 as aneuploid, whereas by cell image analysis 30 were diploid and 71 aneuploid (P less than 0.002). There were 20 tumours with discrepancies between the two methods; 18 of these were tumours with only one peak in flow analysis, but determined to be aneuploid with image analysis. DNA content as measured by both methods was significant for predicting relapse and survival by log-rank test, as were tumour histological grade, c-erbB-2 expression and tumour size. Multivariate analysis showed DNA ploidy measured by flow cytometry to be the only variable of independent significance (P less than 0.02) for both relapse and overall survival. Compared with cell image analysis, flow cytometry demonstrated a significantly higher proportion of diploid tumours, which may be related to differences in the internal standards applied to each method. We suggest that cell image analysis techniques can provide more sensitive information on the DNA content of tumour cells by direct measurement of nuclear DNA density of both normal lymphocytes and tumour cells in the same section. However, although image analysis appears to be more sensitive than flow cytometry in detecting DNA aneuploidy, the image technique appears to lack the specificity of flow cytometry in correlation with clinical outcome.

Adult↗
PubMed1992

Influence of time of administration on verapamil pharmacokinetics.

The plasma concentration-time profile of verapamil was studied in eight healthy drug-free volunteers after oral administration of a single 80 mg dose of the drug on six separate occasions at different times of day (4 AM, 8 AM, noon, 4 PM, 8 PM, and midnight). The median maximum plasma concentration of verapamil was significantly higher after the 8 AM and noon administrations (p less than 0.05) than at any other time. The median area under the concentration-time curve was also significantly higher (p less than 0.05) after administration at 8 AM and noon than at other times. The median time to maximum concentration was not significantly different at any time point (p greater than 0.05). It is possible that concentration-related adverse effects of verapamil could be avoided by choosing the time of day when the drug is prescribed. This concept may also apply to other drugs that have circadian effects in their pharmacokinetic profiles.

Administration, Oral↗
PubMed1992

High-frequency audiometric monitoring for early detection of aminoglycoside ototoxicity.

Treatment with aminoglycosides is known to cause irreversible hearing loss, typically affecting higher-frequency hearing first and progressing to lower frequencies. Standardized methodology has not been developed for early detection of ototoxicity. Serial conventional (0.25-8 kHz) and high-frequency (9-20 kHz) hearing threshold monitoring was done prospectively in 53 hospitalized patients administered aminoglycosides. Hearing loss occurred in 47% of the ears studied, with hearing loss first appearing in the high-frequency range in 71% of ears showing change. Analysis of data on an individual basis revealed a five-frequency range most susceptible to initial ototoxicity. Testing only this range would have resulted in early identification of 82% of ears showing change. Results confirm the critical need for serial auditory threshold monitoring encompassing high frequencies in patients receiving aminoglycosides. A shortened five-frequency monitoring protocol is presented and suggested for use with patients unable to tolerate lengthy audiometric testing procedures.

Amikacin↗
PubMed1992

Generic prescribing of antidepressants.

Analysis of National Health Service prescription data for the antidepressants from 1980 to 1989 shows a consistent secular trend towards the increased use of generic names on prescriptions for this group of drugs. This apparently reflects national trends for all drugs, and was similar for most antidepressants. However, generic prescribing had by 1989 increased significantly more rapidly with fluvoxamine, which was introduced in 1987. The two drugs introduced in 1989, fluoxetine and amoxapine, also had a high generic prescribing rate in their year of introduction. Increased generic prescribing may become a feature with further new drugs. However, the use of the generic name on the prescription has relatively little influence on what is dispensed to the patient. Pharmacists may dispense a brand name when given a generic prescription. Moreover, pressures on doctors to write generic names on prescriptions may have limited relevance for some drugs; generic alternatives were available for only four out of 22 antidepressants.

Amoxapine↗
PubMed1992

Comparing laboratory and portable tone-burst auditory brain-stem-response (ABR) systems for monitoring high-frequency (> or = 8 kHz) auditory function.

High-frequency (8-20 kHz) hearing sensitivity is of special interest because of its early warning potential for ototoxicity. Many ill patients, however, are unable to respond behaviorally to auditory test procedures. To objectively monitor high-frequency auditory function in these patients, laboratory instrumentation to evoke the auditory brain-stem response (ABR) with high-frequency (8-14 kHz) tone-burst stimuli was developed and documented. To provide evaluation at bedside, a portable high-frequency tone-burst generator was developed to elicit the ABR. Combined with a portable signal averager, this system was validated by comparison with the laboratory system. Thirty-five normal-hearing subjects were used to compare ABRs to high-frequency tone bursts from each system. Analysis of responses to tone bursts revealed no significant mean latency differences, and no significant intersession reliability differences between systems. These results confirm that the portable system is comparable to the laboratory system in obtaining reliable high-frequency tone-burst responses.

Acoustic Stimulation↗
PubMed1992

Intravenous regional calcium gluconate perfusion for hydrofluoric acid burns.

We report a case in which acute digital hydrofluoric acid burns were treated with regional intravenous perfusion of calcium gluconate to relieve pain and protect from further tissue damage. This is the first documented instance of this technique being used. The conventional treatments for digital hydrofluoric acid burns all have their shortcomings; intravenous regional perfusion of calcium gluconate may be an effective method of treatment for digital hydrofluoric acid burns.

Burns, Chemical↗
PubMed1992

Suicide and fatal antidepressant poisoning.

OBJECTIVE: To compare the fatal toxicities of antidepressant drugs in England, Scotland and Wales 1985-1989. METHODS: Epidemiological retrospective study using Department of Health prescription data and mortality data from the Office of Population Censuses and Surveys, and the Registrar General for Scotland, for the years 1974-1989. The fatal toxicity index (FTI) of groups of drugs and individual drugs was compared with the FTI for all antidepressant drugs for the years 1985-1989. RESULTS: Of 3,604 single antidepressant deaths between 1975 and 1989, the majority (70.95%) were from amitriptyline or dothiepin. The mean FTI for all drugs for the years 1985-1989 was 35.6; the FTIs for dothiepin, amitriptyline, nortriptyline and tranylcypromine were significantly higher than the mean of all, while those for clomipramine, lofepramine, fluvoxamine, trimipramine, maprotiline, trazodone, mianserin, protriptyline, isocarboxazid and phenelzine were lower. The FTI for the older tricyclic drugs was higher at 43.03 (p < 0.001). The FTI for the monoamine oxidase inhibitors, of 27.03 (p = 0.045), and for all drugs introduced after 1973, of 5.32 (p < 0.001), were each significantly lower than the mean of all drugs. CONCLUSIONS: Overdose deaths from antidepressants have not decreased over the last 15 years. A trend away from prescribing drugs with a higher fatal toxicity index in favour of those with a lower index, would reduce the number of deaths from antidepressant poisoning.

Acute Disease↗
PubMed1992

Toxicity of antidepressants: comparisons with fluoxetine.

Antidepressant drugs have been available for 30 years. Although effective and useful in restoring quality of life, the older drugs in particular have many unwanted properties. The anticholinergic effects of the tricyclic drugs are a major drawback, and the risk of interactions limits the usefulness of the monoamine oxidase inhibitors (MAOIs). Generally, newer drugs including fluoxetine have a more favourable adverse effect profile. Although a number of drugs produce rare but serious adverse effects, overdose toxicity is a matter of greater importance, especially in patients who are at risk of suicide. Toxicity indices, calculated from the number of deaths per million prescriptions for each drug, enable comparisons between drugs to be made. These show that several of the older tricyclic drugs have relatively high mortality in overdose. Many of the newer drugs including fluoxetine have a good record of safety in overdose, and this forms an important part of their risk-benefit profile.

Antidepressive Agents↗
PubMed1992

Early detection of ototoxicity using high-frequency, tone-burst-evoked auditory brainstem responses.

Subjects receiving treatment with ototoxic agents were evaluated concurrently with conventional and high-frequency (> or = 8 kHz) behavioral threshold measures and with ABR to click and to 8, 10, 12, and 14 kHz tone-burst stimuli. Behavioral threshold data revealed ototoxic change in 51 percent of ears evaluated. Of these ears demonstrating behavioral change, 90 percent revealed concurrent ABR changes. If only ABR monitoring with high-frequency tone-burst stimuli had been used, 87 percent of allears showing behavioral change would have been identified. Three fourths of these would have been identified from wave V responses, with 87 percent identified from the two highest frequencies tested for each individual. This research suggests that behavioral change is reflected accurately in the ABR, that high-frequency tone bursts will identify a majority of initial ototoxic changes, and that monitoring hearing with high-frequency, tone-burst-evoked ABRs during treatment with potentially ototoxic agents is significantly more effective than click-evoked ABRs for early detection of ototoxicity.

Acoustic Impedance Tests↗
PubMed1992

Portable stimulus generator for obtaining high-frequency (8-14 kHz) auditory brainstem responses.

Currently, the most useful application of high-frequency (greater than or equal to 8 kHz) auditory evaluation is for serial monitoring of patients receiving potentially ototoxic agents. Many individuals, however, are unable to respond to behavioral auditory test techniques. An objective evaluation method such as the auditory brainstem response (ABR) is valuable with difficult-to-test individuals. Laboratory instrumentation has been demonstrated to evoke high-frequency-specific (8-14 kHz) ABRs with reliable intrasubject latencies over time. This instrumentation is limited, however, because it cannot be transported to the patient confined to a hospital room. A portable device has now been constructed to deliver high-frequency (8-14 kHz) tone-burst stimuli comparable to the lab system. This digital/analog high-frequency tone-burst stimulus generator weighs less than 5 pounds. It can be utilized with any ABR signal averager capable of generating a positive (condensing) click at approximately 4.8 volts. Case studies are presented to demonstrate the frequency-specific responses obtained with these high-frequency tone-burst stimuli.

Acoustic Stimulation↗