int-2 amplification in breast cancer: association with decreased survival and relationship to amplification of c-erbB-2 and c-myc

Amplification of the int-2 oncogene was measured in a series of breast tumours and related to amplification of the c-myc and c-erbB-2 oncogenes, histopathological features and relapse-free and overall survival. int-2 was amplified in 11%, c-myc in 20% and c-erbB-2 in 27% of the tumours assessed. int-2 amplification was associated with large tumour size (p < 0.05) and reduced relapse-free (p < 0.05) and overall (p < 0.0005) survival. c-myc amplification was associated with poor tumour differentiation (p < 0.05) but had no association with prognosis. c-erbB-2 amplification was associated with low levels of expression of oestrogen receptor mRNA (p < 0.05), poor tumour differentiation (p < 0.05) and shortened relapse-free (p < 0.0001) and overall survival (p < 0.0001). This is the first report of an association between amplification of the int-2 oncogene in breast tumours and a significantly increased risk of death from breast cancer, and suggests that int-2 may be useful for identifying breast-cancer patients having a poor prognosis.

High-frequency tone burst-evoked ABR latency-intensity functions

High-frequency tone burst stimuli (8, 10, 12, and 14 kHz) have been developed and demonstrated to provide reliable and valid auditory brainstem responses (ABRs) in normal-hearing subjects. In this study, latency-intensity functions (LIFs) were determined using these stimuli in 14 normal-hearing individuals. Significant shifts in response latency occurred as a function of stimulus intensity for all tone burst frequencies. For each 10 dB shift in intensity, latency shifts for waves I and V were statistically significant except for one isolated instance. LIF slopes were comparable between frequencies, ranging from 0.020 to 0.030 msec/dB. These normal LIFs for high-frequency tone burst-evoked ABRs suggest the degree of response latency change that might be expected from, for example, progressive hearing loss due to ototoxic insult, although these phenomena may not be directly related.

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. Incrased 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

The safety of antidepressants

It is no exaggeration to say that, in the 30 years since antidepressants were introduced, they have revolutionised the management of depression, thus fulfilling, at least for depressive illness, Paracelsus' prophetic wish. We now have a group of drugs which can induce remission in a disease which is disabling and not infrequently fatal. Despite intensive research, however, our understanding of the mechanism of action of these drugs is still largely hypothetical. Even our methods of evaluation are sufficient only to enable one to decide whether an antidepressant drug is effective or ineffective; there is no experimental method which can rank them in an overall order of potency, and perhaps this should not be the aim, since there must be subgroups of depressed patients who will respond differently to any one agent.

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.

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.

Overdose and safety with fluvoxamine

The large number of antidepressants available provides a wide range of choice. While clinical effectiveness is the most important consideration, toxicity in overdose must be considered in the risk-benefit assessment of each antidepressant. There are almost 300 deaths each year in Britain from tricyclic overdose, and very few deaths from newer antidepressants. Fluvoxamine appears to have low toxicity in overdose. Symptoms are often minimal: nausea, vomiting, dizziness and somnolence. There is one reported case of prolonged cerebral depression after ingestion of 5.5 g. Overdoses of up to 9 g have produced minimal symptoms and full recovery. No deaths from overdose with fluvoxamine alone have been reported in the literature, although one death certificate in Britain has mentioned fluvoxamine as the cause of death. Fluvoxamine appears to be a valuable alternative to the tricyclic antidepressants, and has a high margin of safety in overdose.

Pharmacodynamic interactions between infused adenosine and oral theophylline

1. Five healthy human subjects were given, in single-blind fashion, either (a) 625 mg theophylline orally, followed 4 h later, by a 40 min infusion of adenosine (40 micrograms kg-1 min-1 for 5 min, 60 micrograms kg-1 min-1 for 5 min and 80 micrograms kg-1 min-1 for 30 min), or (b) 625 mg theophylline orally followed by 0.9% sodium chloride infusion, or (c) placebo theophylline tablets followed by adenosine infusion. 2. All five subjects experienced adverse effects during adenosine infusion, mainly at the higher infusion rates; two subjects also experienced chest pain but not during combined treatment with theophylline and adenosine. 3. Diastolic blood pressure (DBP) rose by 16.5 mmHg (P less than 0.001) following treatment with theophylline only, fell by 24.5 mmHg (P less than 0.001) during the adenosine infusion after placebo theophylline and remained unchanged during the adenosine infusion following theophylline. Pulse rate rose by 12 min-1 (P less than 0.01) during adenosine infusion following placebo, but not after theophylline alone or theophylline and adenosine combined. 4. The respiratory rate fell by 6 min-1 (P less than 0.01) during treatment with adenosine only, being lower than for the two treatments containing theophylline (P less than 0.05). 5. Plasma potassium and magnesium fell by 0.25 mmol l-1 (P less than 0.001) and 0.037 mmol l-1 (P less than 0.05), respectively, during treatment with theophylline only, but these effects were not altered by infusion of adenosine. 6. This study has demonstrated interactions between theophylline and adenosine on diastolic blood pressure and respiratory rate, but no interaction on metabolic parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of the pNR-2/pS2 protein in diverse human epithelial tumours

The pNR-2/pS2 protein is regulated by oestrogens in breast cancer cell lines. This report describes a systematic survey of pNR-2/pS2 expression in a number of common epithelial tumours. Expression was evaluated immunohistochemically in an archival series using antisera raised against the C-terminus of the pNR-2/pS2 protein. Expression of pNR-2/pS2 by malignant epithelial tumours was widespread. Intense immunohistochemical staining was found in tumour cells in a proportion of pancreatic (6/8), large intestinal (7/12), gastric (9/16) and endometrial (4/12) carcinomas. Positive staining for the pNR-2/pS2 protein was also found in both benign and malignant ovarian epithelial tumours and was very significantly associated with mucinous differentiation (P less than 0.00001). Small numbers of carcinomas of bladder (2/10) and prostate (2/7) showed less intense staining and single examples of cervical carcinoma (1/7) and lung carcinoma (1/19) stained positively. None of the renal carcinomas (0/16) examined stained positively. Positive staining showed no correlation with gender. Although there are reports of oestrogen receptor expression in most of the tumour types considered, the possibility of other regulatory influences must also be considered. The pNR-2/pS2 protein may well have a more general role in human epithelial neoplasia than hitherto realised.