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Biomedical subjects

J Kirk

Publications and source records attributed to J Kirk.

At least 127 records · Page 7Linked to original sources
PubMed1987

Descriptive epidemiology of anestrus in Michigan Holstein-Friesian cattle.

Twenty-two Michigan Holstein-Friesian herds were studied to determine the incidence and epidemiology of anestrus. In 3,309 lactations studied, 42% were classified as having exhibited preservice anestrus (no estrus detected by 70 d after calving). Organic reasons (pyometra, cystic follicles, static ovaries) were identified by palpation per rectum for 237 (23%) of the cows with preservice anestrus that were examined by a veterinarian. Postservice anestrus, defined as failure to show estrus within 35 d after an unsuccessful insemination, was identified in 790 (47%) of 1,691 lactations. Veterinary examination identified 104 (20%) of postservice anestrous cows as having this condition because of organic causes. The average cow with preservice anestrus had an increase of 30 d open compared to her herdmates, and the average cow with postservice anestrus had an increase of 37 d open. Anestrous cows produced more milk than their unaffected herdmates in both the current and the previous lactation. Analysis of composite lactation curves indicates that, for preservice anestrus, this additional milk production was obtained gradually over the entire lactation. Anestrous cows were culled at a significantly higher rate than their herdmates. Cows with preservice anestrus were more likely to have begun their lactation in the spring months.

Journal Article↗
PubMed1987

Assessment of function in routine clinical practice: description of the COOP Chart method and preliminary findings.

The COOP Project, a primary care research network, has begun development of a Chart method to screen function quickly. The COOP Charts, analogous to Snellen Charts, were pretested in two practices on adult patients (N = 117) to test feasibility, clinical utility, and validity. Patients completed questionnaires containing validated health status scales and sociodemographic variables. Practice staff filled out forms indicating COOP Chart scores and clinical data. We held debriefing interviews with staff who administered the Charts. The results indicate the Charts take 1-2 minutes to administer, are easy to use, and produce important clinical data. The patterns of correlations between the Charts and validity indicator variables provide evidence for both convergent and discriminant validity. We conclude that new measures are needed to assess function in a busy office practice and that the COOP Chart system represents one promising strategy.

Activities of Daily Living↗
PubMed1987

Prognostic factors in bulimia nervosa.

Factors predictive of outcome were sought from the data from a controlled study of the treatment of bulimia nervosa. Four different indices of outcome were used, and outcome was assessed at four points during a 12-month, treatment-free follow-up period. It was found that the pre-treatment level of self-esteem was a consistent predictor of outcome with those patients having low self-esteem responding least well to treatment. There were no other consistent predictors of outcome.

Behavior Therapy↗
PubMed1987

Chief complaint fatigue: a longitudinal study from the patient's perspective.

Fatigue is one of the 10 most common reasons for visiting a physician. Yet little is known about its course or impact, from the patient's perspective, on quality of life or utilization of medical care. The Dartmouth COOP Project, a primary care research network, conducted a one-year prospective study comparing chief complaint fatigue (CCF) patients with two age/sex matched comparison groups (N = 243). Results show that almost 67% of the CCF patients improved over one year; however, they had much higher utilization rates and substantial limitations in physical and emotional function. Fatigue was associated with physical symptoms and interference with many aspects of daily life. We conclude that fatigue has a powerful, adverse effect on quality of life. We hope the findings may help physicians to better understand and treat patients who seek care for fatigue.

Fatigue↗
PubMed1985

The significance of the neurotic symptoms of bulimia nervosa.

The significance of the neurotic symptoms of bulimia nervosa is a subject of current debate. In the present paper, data are reported on changes in these symptoms during the course of psychological treatment directed at the eating disorder itself. A significant association was found between outcome in terms of eating habits and the severity of neurotic symptoms after treatment. There was no association between outcome and the pre-treatment level of neurotic symptoms. These findings suggest that the neurotic symptoms are likely to constitute a secondary psychological reaction.

Adult↗
PubMed1984

Can cell survival parameters be deduced from non clonogenic assays of radiation damage to normal tissues?

Though dose-response curves for large scale radiation injury to tissues are undoubtedly related to survival curves for clonogenic cells, the relationship between the two sets of curves is not necessarily simple. Sterilization of clonogenic cells occurs near-instantaneously by comparison with the protracted lag period for gross injury to tissues. Moreover, with some types of macroscopic damage, the shapes of the dose-response curves may depend on time of assay. Changes in the area or volume of irradiated tissue may also influence the shapes of these curves. The temporal pattern of expression of large scale injury also varies between tissues, and two distinct groups can be recognized. In rapidly proliferating tissues, the lag period is almost independent of dose, whilst in slowly proliferating tissues, it is inversely proportional to dose. This might be explained by invoking differences in corresponding proliferative structures of the tissues (Three compartmental Type H versus One compartmental Type F proliferative organization). For the second group of tissues, in particular, mathematical modelling suggests a systematic dissociation of the dose-response curves for clonogenic cell survival and for large scale injury. This dissociation, which arises even in the case of single doses, may be even more important when radiation is fractionated. In particular, it may be difficult to disentangle the contributions made to inter-fraction sparing by cellular repair processes and by proliferation-related factors.

Animals↗
PubMed1983

Functional health status levels of primary care patients.

A cross-sectional study was conducted on functional status of adults visiting primary care practices. Limitations in physical and mental function were assessed independently in 28 practices by patients (N = 1,227) and physicians (N = 47) using a simple global index of disability. Results indicated 12% of patients rated their physical limitations as major and 8% rated major emotional limitations during the past month. Comparable assessments by physicians were 5% and 4%, respectively. Differences between patients and physicians were statistically significant and are demonstrated to be clinically relevant. Patients' functional limitations were associated with increased utilization of ambulatory care, older age, lower level of education, unemployment, and a primary diagnosis of a chronic condition. We conclude that functional status can be routinely recorded in medical practice to help describe severity, predict utilization, and improve the physician-patient relationship.

Activities of Daily Living↗
PubMed1983

Experimental penetrating head injury: some aspects of light microscopical and ultrastructural abnormalities.

A high velocity model of penetrating head injury has been developed in the rhesus monkey and a lower velocity model in the baboon. It is apparent that pathological changes are widespread and develop early although the pathogenesis of the diffuse vascular changes is unknown. The present study involved the sampling of grey and white matter from 20 monkeys with high velocity injury, and 10 baboons with low velocity injury together with similar material from a number of normal control animals. 30 minutes after a high velocity injury swelling of perivascular astrocytes was present, sometimes associated with an increase in extracellular fluid. Animals with lower velocity injuries survived for some hours. Astrocytic swelling and perivascular oedema associated with cellular necrosis was frequently found in this group. The pathogenesis of these lesions is discussed.

Animals↗
PubMed1983

An ultrastructural study of experimental high velocity penetrating head injury.

Experimental high velocity missile brain injury in the rhesus monkey produces widespread swelling of perivascular astrocytes within 30 min of injury. Possible mechanisms for this lesion include a direct effect of force, chemical mediation secondary to the extravasation of blood, alterations in the permeability of the blood brain barrier and ischaemia. The implications of this findings for the function of the blood brain barrier, for neurotransmission and for neuronal survival are discussed.

Animals↗
PubMed1983

The establishment and characterization of a cell line and mouse xenografts from a human malignant melanoma.

A permanent cell line has been established from a human intracranial secondary melanoma. During 3 years of continuous growth in vitro the cells have maintained their characteristic phenotypic properties including melanin production. The cultured cells are highly tumorigenic in the athymic mouse and the tumours produced are histologically identical to the human tumour of origin.

Animals↗
PubMed1982

Weekly large fraction radiotherapy and 5 fluorouracil as a palliative treatment for large bowel carcinoma: a pilot study.

Palliative radiotherapy for large bowel cancer is generally given in fraction sizes of 2-3 Gy. Theoretical considerations led us to believe that a larger fraction size would not lead to a decreased response rate and practical considerations led us to treat patients once a week. The results of a pilot study of 32 patients with large bowel cancer are presented. Patients were treated with a fraction size of 6 Gy given weekly and combined with 5 FU. The response rate of 58% and the median survival of 9 months seems comparable with other regimens, as does the rate of acute side effects. The late high dose effect of subcutaneous fibrosis was seen in 30% of the long term survivors; the implications of this are discussed. We draw the conclusion that this treatment is convenient and effective in terms of tumor response, but that the late high dose effects were more severe than expected and that these effects may be potentiated by 5 FU.

Adenocarcinoma↗
PubMed1982

The effect of irradiation on function in self-renewing normal tissues with differing proliferative organisation.

The primary effect of irradiation on self-renewing normal tissues is sterilisation of their proliferative cells, but how this translates into failure of tissue function depends on the mode of organisation of the tissue concerned. It has recently been suggested (Michalowski, 1981) that proliferative normal tissues may be classed as "hierarchical" (like haemopoietic tissues) or as "flexible" (like liver parenchyma) and that radiation injury to tissue function develops by different pathways in these tissues. Mathematical model studies confirm the different radiation responses of differently organized tissues. Tissues of the "flexible" or "F-type" category display a variety of novel radiobiological properties, different from those of the more familiar "hierarchical" or "H-type" tissues. The "F-type" responses are strongly influenced by radiation-sterilised ("doomed") cells, and it is suggested that the rôle of "doomed" cells has been undervalued relative to that of clonogenic survivors. Since "F-type" tissues have characteristically low rates of cell renewal, it is possible that these tissues are preferentially responsible for late effects of irradiation in clinical radiotherapy.

Cell Division↗
PubMed1982

Dose response experiments using the mouse tail model.

Radiation induced tail necrosis in BALB/c mice was used to investigate the effects of tissue temperature and local oxygenation on the radiation response. Single doses of 250 kV roentgen-rays were given over the temperature range 32.5 to 37 degrees C and dose response curves obtained. The temperature dependence of the response was shown to be consistent with changing hypoxic status by the derivation of a simple model; this has practical implications for the treatment of patients using simultaneously combined radiation therapy and hyperthermia.

Animals↗