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Biomedical subjects

C Muir

Publications and source records attributed to C Muir.

34 records · Page 2Linked to original sources

Strange-male-induced pregnancy disruption in mice: potentiation by administration of 17 beta-estradiol to castrated males.

Previous evidence suggests that androgen activity is necessary for strange males to disrupt early pregnancy in mice. Inseminated females were housed below castrated males, separated by a wire-mesh grid. Castrated males did not disrupt pregnancy, whereas those given daily injections of 27 or 81 micrograms of 17 beta-estradiol did so. In conjunction with previous evidence, these data suggest a similarity between the hormones involved in the capacity of males to disrupt pregnancy and the hormones directly implicated in the females' vulnerability to pregnancy disruption.

Animals↗

Registration of colorectal cancer in Scotland: an assessment of data accuracy based on review of medical records.

Colorectal cancer accounts for a substantial burden of morbidity and mortality in the population. While the need for reliable incidence data may be self-evident, the quality of cancer registration data has rarely been assessed. In Scotland during 1993, the medical records of a random sample of cancer registrations attributed to the year 1990 were sought. The sample contained 238 registrations of colorectal cancer, 217 (91%) of which had relevant medical records available for review. Registration details were reabstracted from available records and compared with data in the registry. Discrepancies in identifying items of data (surname, forename, sex and date of birth) were recorded in eight cases (3.7%, 95% confidence intervals 1.2-6.2%). None would have disturbed record linkage. Discrepancy rates of 3.7% (1.2-6.3%) in postcode of residence at the time of diagnosis (excluding differences arising through boundary changes), 8.3% (4.6-12.0%) in 'anniversary date' (excluding differences of 30 days or less), 2.8% (0.6-5.0%) in histological verification status and 13.5% (8.9-18.1%) in morphology code (excluding 'inferred' morphology codes) were recorded. Twelve cases (5.5%, 2.5-8.6%) were deemed not to warrant site codes for cancer of the colon (ICD-9 153) or rectum (ICD-9 154). In many respects, therefore, the data held about registrations of colorectal cancer in Scotland appear to show a high level of accuracy. Completeness of case ascertainment has still to be formally assessed.

Abstracting and Indexing↗

Registration of non-melanoma skin cancers in Scotland--how accurate are site and morphology codes?

Although under-reporting of non-melanoma skin cancers to cancer registries is widely acknowledged, less is known about the accuracy of information held about registered cases. In 1993, the accuracy of a random sample of cancer registrations in Scotland attributed to the year 1990 was assessed by reference to relevant medical records. The sample contained 290 registrations of non-melanoma skin cancers, 251 (90%) of which had records available for scrutiny. Here we report the results of a detailed analysis of the accuracy of site and morphology coding of non-melanoma skin cancers. Following reabstraction of details from available medical records, only three cases (1.2%) did not retain the same first three digit ICD-9 site code (173.--), although a further three cases were judged to have been registered in error. There were 56 (21.5%) discrepancies in morphology coding, but 21 of these arose through inferences about morphology in the absence of microscopic confirmation, and most of the remainder were of a relatively minor nature. In summary, it does seem possible to collect data about non-melanoma skin cancers to a reasonably high standard of accuracy. This provides some justification to those who advocate an increased effort directed towards improving levels of completeness of case ascertainment.

Humans↗

Estimating avoidable causes of cancer.

Evidence that much cancer is preventable derives from observations of time trends and geographic patterns of cancer, birth cohort changes, high risks in groups with well-defined exposures, and experimental studies. In an effort to identify additional opportunities for reducing the impact of cancer on society, this conference assessed avoidable causes of cancer. The magnitude and extent of preventable causes of cancer are subjects of intense debate, with discrepancies often related to the use of different time frames and different weights for epidemiologic and toxicologic evidence. There is much agreement, however, about the exposures that increase risk, notably tobacco, alcohol, diet, radiation, medications, occupational exposures, general environmental exposures, and infectious agents. Interactions between carcinogenic exposures and genetic susceptibility are also important. Concerted efforts are needed to identify avoidable causes of cancer and to apply knowledge already obtained to reduce the cancer burden.

Alcohol Drinking↗

How accurate are Scottish cancer registration data?

In order to assess the accuracy of Scottish cancer registration data, a random sample of 2,200 registrations, attributed to the year 1990, was generated. Relevant medical records were available for review in 2,021 (92%) cases. Registration details were reabstracted from available records and compared with data in the registry. Discrepancies in identifying items of data (surname, forename, sex and date of birth) were found in 3.5% of cases. Most were trivial and would not disturb record linkage. Discrepancy rates of 7.1% in post code of residence at the time of diagnosis (excluding differences arising through boundary changes), 11.0% in anniversary date (excluding differences of 6 weeks or less), 7.7% in histological verification status, 5.4% in ICD-9 site codes (the first three digits) and 14.5% in ICD-O morphology codes (excluding 'inferred' morphology codes) were recorded. Overall, serious discrepancies were judged to have occurred in 2.8% of cases. In many respects, therefore, Scottish cancer registration data show a high level of accuracy that compares favourably to the reported accuracy of the few other cancer registries undertaking such analyses.

Female↗

Correlations between dose, plasma concentrations, and antispastic action of tizanidine (Sirdalud).

In a double blind, placebo controlled, cross over study the correlations between single doses (2, 4, and 8 mg), plasma concentrations, and antispastic action of tizanidine were investigated in 16 patients with extensor spasticity of the legs due to multiple sclerosis. An electrogoniometer was used to assess muscle tone at knee extensors, applying Wartenberg's pendulum test. Blood samples, a clinical assessment of muscle tone by the Ashworth scale, and muscle strength by the British Medical Research Council scale were obtained concomitantly. Confirmatory analysis using the change in the relaxation index (R2 value) 1.5 hours after each treatment, showed a statistically significant (p = 0.0123) linear dose-response relation between single doses and antispastic action of tizanidine. Further statistical analysis showed a strong within patient linear correlation between plasma concentrations and antispastic action at 4 and 8 mg doses (p = 0.014 and 0.004 respectively), but only weak between patient correlations. The analysis of the dose-plasma concentration relation showed results consistent with linear pharmacokinetics. The comparison of changes in the R2 ratio with concomitant Ashworth scores showed a significant correlation between the two. It is concluded that there are linear correlations between single doses, plasma concentrations, and antispastic action of tizanidine. Because of the strong within patient but weak between patient correlation between plasma concentrations and antispastic action of tizanidine the effective doses should be determined individually.

Adult↗

Pharmacokinetics and pharmacodynamics of tizanidine.

The relationship among tizanidine dose, plasma concentration, and antispastic action is linear in nature. Response to a given dose of this agent varies among patients, and determining the appropriate clinical dose requires individual titration.

Clonidine↗

Fluoxetine ingestion: a one year retrospective study.

Fluoxetine (PROZAC) is a recently marketed straight chain antidepressant unrelated to the cyclic anti-depressants. There is only limited information on fluoxetine and a single case report on overdose (benign outcome) in the literature. In response to this we performed a 1y retrospective chart review at 2 AAPCC certified poison centers. Forty-four exposures to fluoxetine were reviewed from 1988; 31 cases were treated in a HCF, 2 cases were followed at home by phone and 11 cases were lost to follow up. Thirteen cases with follow up (FU) reported no coingestants; 3 cases reported increased anxiety without cardiovascular (CV) changes, 2 cases presented confused with out CV changes, and 8 cases were asymptomatic. Eight cases with FU had ETOH and/or benzodiazepines as a coingestant and experienced only a decreased level of consciousness that could be explained by the coingestant. Five cases remained asymptomatic with reported coingestants of APAP #3, lorazepam, haloperidol, molindone, alprazolam, propranolol, phenobarbital (level 18.2). Four cases were excluded from the evaluation due to the coingestants involved. No seizures were recorded in this series. Three possible drug reactions occurred; 2 cases had reactions with tranylcypromine (PARNATE), and 1 case with a diagnosis of septicemia had a severe hyperthermic reaction with therapeutic coingestants of mephytoin, verapamil, digoxin and indocin. We believe overdose with fluoxetine present minimal risk of serious cardiovascular or neurological complications.

Accidents↗

The international comparability of cancer mortality data. Results of an international death certificate study.

In preparation for the 10th revision of the International Classification of Diseases (ICD-10), a two-part study was undertaken to assess the international comparability of the coding, by the 9th revision (ICD-9), of death certificates mentioning cancer, to see whether there had been improvement since the 8th revision (ICD-8). Part I repeated a 1978 study in which nine countries coded the same 1,234 United States death certificates mentioning cancer by ICD-9. The proportion of disagreements in coding the underlying cause of death fell about 35% between 1978 and the present study. This reduction was probably due to the new more detailed rules for coding cancer death certificates given in ICD-9. To combat the criticism of the possible bias associated with using United States death certificates only, in Part II of the study, each of seven countries submitted about 100 certificates translated into English which had posed problems in coding cancer. Discrepancies in assigning the underlying cause of death were found for 54% of these problem certificates. The major types of problems identified were coding when multiple cancer sites were mentioned on the death certificate, whether to select heart disease or cancer as the underlying cause of death, and the interpretation of the coding rules. Better rules for ICD-10 must be provided for both physicians and coders if international comparability of cancer mortality data is to be achieved.

Abstracting and Indexing↗