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Biomedical subjects

R Kay

Publications and source records attributed to R Kay.

At least 253 records · Page 14Linked to original sources
PubMed1977

Antigenicity of frozen and fresh spermatozoa.

Since cryopreservation of spermatozoa causes surface changes, we tested whether specific antigens associated with the plasmalemma might be dislodged or destroyed during freezing. When we compared the use of frozen sperm with the use of fresh sperm in indirect immunofluorescence tests for antisperm antibodies, we found changes in antigenicity. There was a decrease in antigenicity of the acrosomal region, and antigenicity of the sperm tail was increased with the addition of 10% glycerol, with or without cryopreservation. These results suggest that women who are infertile and, as demonstrated by immunofluorescence, have antibodies to sperm may be aided by artificial insemination with the husband's cryopreserved sperm.

Antibodies↗
PubMed1975

A family study of coeliac disease.

Studies by Thompson, 1 Carter et al, 2 MacDonald et al. and McCrae 4 have all shown a high familial frequency of coeliac disease (CD). The diagnostic criteria differed in each study; in Thompson's patients the diagnosis was based on clinical or historical data alone; in Carter's study response to a gluten-free diet was required, while in MacDonald's and McCrae's studies the diagnostic criteria included the demonstration of the lesion of CD by small bowel biopsy. In MacDonald's study some asymptomatic cases were discovered and a few of these had normal fat balance results. No hereditary pattern emerged from these studies though MacDonald postulated a dominant gene with variable penetrance while McCrae suggested that susceptibility to CD is inhereited multifactorially and that enviromental factors other than dietary gluten are of aetiological importance. Hoffman et al. 5, on the other hand, have described discordance for CD in identical twins.

Adolescent↗
PubMedDate not supplied

Quality control during the conventional analysis of semen, an essential exercise.

Intra- and inter-technician variability in assessing sperm motility by the methods recently advocated by the World Health Organization (WHO) were studied. The intra- and inter-technician variability in estimating sperm concentration and the intra-technician variability in assessing sperm morphology were also examined. Intra-technician variability in assessing sperm motility appeared to be related to the natural ability and/or training of the observer. Although in general the intra-technician variability was low, there were marked and clinically significant differences between observers when assessing the same semen sample. There was no significant difference between observers in the assessment of sperm concentration, and intra-technician variability was low. When assessing sperm morphology, the intra-technician variability was potentially large (above a level of 20% morphologically ideal spermatozoa). Technicians should be recruited who have natural ability as observers. Quality control appears to be an essential exercise for any center that plans to relate semen parameters to fertility outcome.

Evaluation Studies as Topic↗
PubMedDate not supplied

Unbiased assessment of treatment effects on disease recurrence and survival in clinical trials.

Recently there has been considerable discussion concerning the analysis of data and presentation of results from clinical trials in breast cancer. A problem stems from there being several events of interest, notably disease recurrence and death. Current methods based on 'so-called' disease-free survival are criticized on the grounds that they confuse events, such as disease recurrence and death, in the treatment comparison and consequently could be very misleading. Alternative methods of analysis, based on separate measures of treatment effect are presented and illustrated.

Breast Neoplasms↗
PubMedDate not supplied

The wasted leg syndrome, a single fibre electromyographic study of arms and legs.

Single fibre electromyography (SFEMG) was performed on 11 patients with the wasted leg syndrome. Five were of South Asian origin and the others Chinese. In most cases the disorder progressed for about 5 yr before becoming static or very slowly progressive. The SFEMG fibre density was increased similarly in both the affected and less affected leg, but was normal in the arms except for a few longstanding cases. The limited extent of clinical and electrophysiological abnormalities suggests that the wasted leg syndrome is a distinct entity.

Adolescent↗
PubMedDate not supplied

The effects of fixed and articulated ankle-foot orthoses on gait patterns in subjects with cerebral palsy.

Twenty-one subjects with spastic diplegic cerebral palsy were studied to quantify the effects of fixed and articulated ankle-foot orthoses (AFOs) on gait and delineate criteria for their use. Children underwent gait analysis under three conditions, fixed AFOs (FAFOs), articulated AFOs (AAFOs), and shoes alone. Greater dorsiflexion occurred at initial contact with both FAFOs and AAFOs than shoes alone. Dorsiflexion at terminal stance was greatest in AAFOs. Plantarflexor power generation at preswing was preserved in AAFOs. No differences were found in knee position during stance. Knee-extensor strength was positively related to knee extension during stance. No relationships were found between dorsiflexion range of motion, calf spasticity and strength, and peak dorsiflexion during stance. AAFOs are appropriate for subjects with varying degrees of calf spasticity, as long as adequate passive range of motion is available. These findings can be applied primarily to children who do not have a preexisting tendency to crouch.

Adolescent↗
PubMedDate not supplied

Denial predicts favorable outcome in unstable angina pectoris.

Denial may be prognostically favorable in patients with acute myocardial infarction. We analyzed the significance of denial in 26 patients referred to a tertiary care center for advanced therapy of unstable angina. Group A comprised 14 patients characterized as deniers on the Hackett--Cassem Denial Scale. Group B comprised 12 nondeniers. There were no differences between groups in multiple baseline social and demographic characteristics, cardiac history, or risk factors. Similarly, there were no differences in the number of diseased vessels or left ventricular function in those patients catheterized (11 Group A patients, 9 Group B patients). Group B, however, had a longer hospitalization until medically stabilized (pain-free for 36 hr) than Group A (5.9 +/- 3.6 days vs. 3.0 +/- 1.6 days; p = 0.02) despite similar treatment regimens. There were no significant differences in incidence of myocardial infarction or need for surgery. There were two deaths--both in Group B patients. We conclude that denial independently predicts rapid medical stabilization in unstable angina patients. Whether it predicts better longterm outcome requires further study.

Angina Pectoris↗
PubMedDate not supplied

Postcoital test: which form of spermatozoal motility is associated with a good fertility outcome?

The objectives of this study were to examine the predictive value of the PCT in relation to treatment-independent conception rates, to determine which cutoff point best predicted fertility outcome, and which form of spermatozoal motility on PCT is most significantly related to fertility outcome. A prospective study was undertaken of couples referred for the investigation of "unexplained" infertility. One hundred and twenty six couples were recruited between July 1984 and April 1986. On further investigation female infertility factors were identified in 32 (25%) of couples, who were therefore excluded from the study. All conceptions were treatment independent. The relationship between the result of the postcoital test and the chance of conception was studied using a modification of Cox's regression model of life table analysis. The mean length of involuntary infertility prior to referral was 75 months (range = 18-192, SD = 39.2). The mean length of follow-up was 18 months (range = 1-34, SD = 8.4). A 98% follow-up rate was achieved. Eighteen women conceived, giving a 32-month treatment-independent conception rate of 22%. A cutoff point of one spermatozoon exhibiting sluggish motility per HPF was the most effective method of classifying the results of the postcoital test (X2(1) = 4.28, P = 0.037, RR = 4.7. This would suggest that the most efficient form of spermatozoal motion in cervical mucus is slow or sluggish motility.

Adult↗
PubMedDate not supplied

The importance of employing stringent methods to recruit fertile male controls.

Two methods of recruiting fertile male controls were evaluated and compared. The first group was recruited from the partners of women attending an antenatal clinic without obtaining details of their reproductive history. The second group was recruited after obtaining a detailed reproductive history from the couple and employing stringent entry criteria. Entry criteria for the second group included a length of exposure to the risk of pregnancy of not more than 12 months and no previous episode of involuntary infertility for either partner. There were significant differences between the distributions of semen parameters obtained from the two groups, indicating that the selection criteria for "fertile" men significantly influence results obtained and therefore that it is important to employ stringent criteria for the recruitment of fertile male controls. The group which was recruited by stringent criteria (mean length of exposure to the risk of pregnancy of 3 months) was characterised by a significantly higher median concentration of spermatozoa which exhibited slow linear or nonlinear motility. This confirms the findings of a previous study which suggested that slow linear or nonlinear motility are superior forms of spermatozoal motion.

Adult↗
PubMedDate not supplied

Statistical principles for clinical trials.

If a trial is to be well designed, and the conclusions drawn from it valid, a thorough understanding of the benefits and pitfalls of basic statistical principles is required. When setting up a trial, appropriate sample-size calculation is vital. If initial calculations are inaccurate, trial results will be unreliable. The principle of intent-to-treat in comparative trials is examined. Randomization as a method of selecting patients to treatment is essential to ensure that the treatment groups are equalized in terms of avoiding biased allocation in the mix of patients within groups. Once trial results are available the correct calculation and interpretation of the P-value is important. Its limitations are examined, and the use of the confidence interval to help draw valid conclusions regarding the clinical value of treatments is explored.

Clinical Trials as Topic↗
PubMedDate not supplied

Survival, disability, and residence 20 months after acute stroke in a Chinese population: implications for community care.

A total of 304 Chinese patients with acute stroke were assessed at 3 and 20 months to determine survival, disability, and place of residence, and so to provide an estimate of the impact on community care resources. Approximately 30% of patients had died by 3 months; thereafter the mortality rate decreased, with a further 13% dying by 20 months. Age, rather than stroke subtype, determined the likelihood of death. Fifty-seven per cent of 3-month survivors were independent at 20 months, with only 18% moderately to severely disabled (Barthel Index less than 15). Thirteen per cent of patients improved and 14% deteriorated between 3 and 20 months. Older subjects had a lower Barthel Index at 20 months, and were more likely to show deterioration. Seventeen per cent of patients were living in institutions by 20 months, predisposing factors being age and mental test score. Although a low Barthel Index was a factor in univariate analysis, it did not contribute to the discriminant function model for predicting institutionalization, and nor did previous stroke, coexisting cardiovascular diseases, or diabetes mellitus influence eventual placement. Approximately 30% of patients were readmitted during the follow-up period, particularly elderly patients and those with a Barthel Index less than 15. Although only 9% of the original cohort required institutional care by 20 months, approximately half of all the government nursing home places in Hong Kong are likely to be taken up by these patients because of the large number of strokes occurring each year.

Aged↗