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Biomedical subjects

P M Crockford

Publications and source records attributed to P M Crockford.

At least 19 recordsLinked to original sources
PubMed1997

Hashimoto's thyroiditis: cytodiagnostic accuracy and pitfalls.

To determine the cytodiagnostic accuracy rate and pitfalls of Hashimoto's thyroiditis (HT), the files and smears prepared from the thyroid needle aspirates of 146 patients with suspected HT and/or clinically and serologically confirmed HT were reviewed. Of those patients, 105 presented with a diffuse and rubbery thyroid enlargement, and 41 with one or two prominent nodules. For the first group (105 patients), the needle aspiration biopsy (NAB) was performed on one or two thyroid lobes during their initial endocrinologic consultation, and for the second group (41 patients), the NAB was performed on and around the predominant nodules that were found either at initial physical examination or during the patients' routine follow-ups. In 134 cases, a cytodiagnosis of HT was made on the first NAB. Among the 41 patients with a prominent thyroid nodule, a thyroid neoplasm was suspected clinically in four because their thyroid nodules increased in size. In the other 12 patients, a cytodiagnosis of follicular neoplasm (FN) was made in five cases, and a Hürthle cell tumor (HCT) was diagnosed or suspected in seven patients. All 16 patients had thyroid surgery, and a HT was histologically confirmed in all cases. In the first four patients, no tumor was found. Among five patients with a cytodiagnosis of FN, one had a hyperplastic follicular cell nodule (HFCN), two had follicular adenomas, and two had papillary carcinomas of follicular variant. For the seven patients with a cytodiagnosis of HCT, HCT was confirmed in three, three were found to have hyperplastic Hürthle cell nodules (HHCN), and one showed a benign colloid nodule with Hürthle cell changes and remote hemorrhagic necrosis. It is concluded that NAB is highly sensitive in diagnosing HT, with a diagnostic accuracy rate of 92% by the first biopsy attempt. The cytologic differential diagnosis between an HFCN and a follicular neoplasm and between an HHCN and an HCT is impossible in some cases.

Adolescent↗
PubMed1995

Requirements for admission to medical school: how many years of university study are necessary?

OBJECTIVE: To assess whether students admitted to medical school after completing 2 years of undergraduate study performed as well as those admitted after longer periods of undergraduate study in terms of broad patient-care skills measured at the time of graduation. DESIGN: Retrospective study. SETTING: University of Alberta, Edmonton. PARTICIPANTS: Graduates of the classes of 1990 and 1991, of the 226 graduates 133 had entered medical school after 2 years of undergraduate training, 39 after 3 years and 54 after 4 or more years. Eight students had been excluded because they were either transfer students or international students. OUTCOME MEASURES: Objective and subjective assessments of the main clinical rotations (internal medicine, obstetrics and gynecology, pediatrics, psychiatry, radiology and surgery), results of the faculty's final comprehensive examination and of the Medical Council of Canada's Qualifying Examination. RESULTS: The students who had completed 2 years of undergraduate study before medical school were significantly younger than those who had completed 3 years and those who had completed 4 or more years (mean age [and standard deviation (SD)] 20.5 [2.1], 21.5 [2.4] and 25.1 [4.4] years respectively, p < 0.001). They also had a significantly higher mean grade point average (GPA) for the prerequisite courses for admission to medical school than those with 3 years and those with 4 or more years of undergraduate study (8.26 [SD 0.3], 7.95 [SD 0.3] and 7.80 [SD 0.5] respectively, p < 0.001). The overall mean GPA for the best 2 years of undergraduate study did not differ significantly between the three groups. The students with 2 years of undergraduate study had a significantly lower mean score for the pre-entry interview than those who had 4 or more years of undergraduate study (32.1 [SD 7.6] v. 38.3 [SD 8.5], p < 0.001). There were no significant differences between the three groups in the results of any of the subjective or objective outcome measures. CONCLUSION: Students who completed 2 years of undergraduate study before admission to medical school were able to achieve a satisfactory level of competency and maturity by the end of medical school. The 2-year option for entrance into medical school should be reconsidered.

Adult↗
PubMed1994

Cardiac tamponade as the initial presentation of papillary thyroid carcinoma.

Hypothyroidism is a well known cause of pericardial effusions and cardiac tamponade; thyroid carcinoma metastatic to the heart and pericardium is rarely encountered in clinical practice. The authors report the case of a 68-year-old male who presented in acute distress from cardiac tamponade. Cytological examination of the pericardial and pleural fluid, and histological examination of a pericardial biopsy revealed a metastatic papillary carcinoma with psammoma bodies. Subsequent reexamination of the patient demonstrated a thyroid nodule and bilateral cervical lymphadenopathy. Fine needle aspiration of the thyroid nodule and cervical lymph nodes detected a papillary thyroid carcinoma with metastases to the lymph nodes. The literature relevant to hypothyroidism, thyroid malignancy and cardiac tamponade is briefly reviewed.

Aged↗
PubMed1989

Pituitary testing with and without bromocryptine in an aspermic man with elevated serum prolactin/FSH levels.

Pituitary testing is reported in an aspermic man with elevated serum FSH levels and hyperprolactinemia. Responses to clomiphene administration were normal. Serum LH responses to a double bolus of GnRH were substantially increased during bromocryptine therapy but FSH responses were similar with and without bromocryptine. These findings suggest that the elevated prolactin levels inhibited the GnRH-LH axis in this patient even in the presence of elevated serum FSH levels.

Adult↗
PubMed1988

Absence of feedback inhibition of prolactin secretion by the prostate.

Previous observations in rodents and man have suggested the existence of feedback inhibition of pituitary prolactin secretion by the prostate. Thyrotrophin releasing hormone (TRH) tests performed in males before and after prostatectomy demonstrated no difference in prolactin or thyrotrophin (TSH) secretion. These data do not support the hypothesis of a prostate-pituitary feedback loop in the control of prolactin secretion. The results also imply that prostatic TRH acts in a paracrine manner.

Aged↗
PubMed1988

Insulin action is altered in hyperthyroidism.

We have assessed insulin action in five hyperthyroid patients, pre- and post-radioactive iodine therapy using oral glucose tolerance tests, monocyte insulin binding and dose response curves generated with the euglycemic clamp technique. All patients had become euthyroid after radioactive iodine therapy with a decline in the plasma free T4 index level from 278 +/- 43 to 105 +/- 9. Fasting glucose was modestly, but significantly elevated in the thyrotoxic patients compared to when they were rendered euthyroid (p less than 0.05). Oral glucose tolerance tests showed no difference in either glucose or insulin values after the glucose load. Insulin receptor binding and affinity were similar regardless of their thyroid status. Hepatic glucose production in the basal state was elevated in the thyrotoxic patients, 61 +/- 5 mg/M2/min vs 49 +/- 3 mg/M2/min (p less than 0.05). At the lowest level of insulin infusion no difference in glucose disposal was found. At maximum insulin concentrations the glucose disposal rate was enhanced in the thyrotoxic patients, 686 +/- 19 vs 567 +/- 26 mg/M2/min (p less than 0.01). These results indicate that higher fasting glucose levels may result from increased hepatic glucose production in thyrotoxicosis, but as indicated by the oral glucose tolerance tests, this defect in insulin action is usually of minor significance. However, insulin responsiveness measured at pharmacological insulin levels is augmented in thyrotoxicosis.

Adult↗
PubMed1987

Insulin action does not change during the menstrual cycle in normal women.

Normal women have alterations in carbohydrate metabolism during pregnancy and when taking oral contraceptives, and clinical observations suggest that diabetic women need more insulin during menstruation. We, therefore, studied insulin action in normal women during the menstrual cycle in the follicular, luteal, and menstrual phases. Glucose tolerance was similar at all three times. Specific insulin receptor binding to monocytes did not change during the menstrual cycle. Euglycemic insulin clamp studies at four different insulin infusion rates (15, 40, 120, and 240 mU/M2 X min) showed no differences in insulin sensitivity or responsiveness throughout the menstrual cycle, and hepatic glucose output did not change. These studies suggest that if insulin action is impaired during menstruation in diabetic women it is because of factors that are not detected in normal women.

Adult↗
PubMed1985

Skeletal challenge: an experimental study of pharmacologically induced changes in bone density in the distal radius, using gamma-ray computed tomography.

Bone density (BD) at the distal end of the radius was measured serially with gamma-ray computed tomography (gamma-CT) in five groups of healthy postmenopausal women. One group comprised untreated controls; women in the other groups were subjected to pharmacologic challenge with putative activators and/or depressors of bone remodeling. The challenge agents, taken orally, were ergocalciferol (vitamin D2) alone and followed by calcium; calcitriol (1,25(OH)2D3), and prednisone. All of the subjects showed changes in BD following challenge; these changes were significant (P less than 0.05) for the groups receiving vitamin D2 and vitamin D2 plus calcium. Responses to ergocalciferol, calcitriol, and prednisone were similar within groups, whereas the group receiving ergocalciferol then calcium comprised two distinct subgroups: bone density transiently increased in one and decreased in the other. For all five groups, the direction of change in bone density in response to the challenge, and its duration and magnitude, were consistent with reported histomorphometric data. We conclude that gamma-CT assessment of change in bone density after pharmacologic challenge provides a useful noninvasive approach to skeletal investigation.

Aged↗
PubMed1984

Hereditary central diabetes insipidus: plasma levels of antidiuretic hormone in a family with a possible osmoreceptor defect.

A large Canadian kindred of Irish extraction extending from Quebec to British Columbia with autosomal dominant diabetes insipidus responsive to exogenous antidiuretic hormone (ADH) is described. Out of 121 individuals 34 have been identified as affected in seven generations. The disorder is characterized by variability in age at onset and in severity, and by apparently spontaneous abatement in old age. The affected subjects do not appear to manifest hypertension or its sequelae. In three individuals tested the plasma ADH level was very low in spite of adequate osmotic stimulation. However, the level rose in two of them when they were given furosemide, which suggests an osmoreceptor defect and a normal ADH response to volume change.

Adult↗
PubMed1984

Effects of two "lipid-lowering" diets on plasma lipid levels of patients with peripheral vascular disease.

Fifty subjects with peripheral vascular disease were randomly assigned to either the American Heart Association Hyperlipidemia Diet C (AHA, N = 23) or a higher fiber, low fat diet based on the Pritikin maintenance diet (HFD, N = 27) and studied for a 12-month period. Diet counseling was provided, and the subjects were encouraged to exercise regularly, to decrease their consumption of salt, alcohol, and caffeine, and to restrict cigarettes as much as possible. Dietary intake data showed that energy distribution was approximately 49% and 64% carbohydrate, 20% and 22% protein, and 31% and 14% fat for the AHA and HFD groups, respectively. Cholesterol and dietary fiber intakes averaged 201 mg and 23 gm per day, respectively, for the AHA group and 108 mg and 43 gm per day, respectively, for the HFD group. Generally, both groups showed tendencies toward decreased serum triglycerides, cholesterol, and LDL cholesterol and increased HDL cholesterol. The HFD group achieved a significant decrease in serum cholesterol (at month 12) (p less than .01). The only significant between-group difference was in serum cholesterol at 4 months (p less than .01), with the lower value in the HFD group. There was a consistent negative correlation between dietary fiber and serum cholesterol levels (p less than .01). Average weight loss was 4.1 kg for the AHA group and 6 kg for the HFD group. We concluded that both dietary regimens, combined with exercise, can be of benefit to patients with peripheral vascular disease.

Aged↗
PubMed1982

Leydig cell hypogenesis: a rare cause of male pseudohermaphroditism and a pathological model for the understanding of normal sexual differentiation.

We describe a patient who presented for treatment of primary amenorrhea and was found to have male pseudohermaphroditism due to Leydig cell hypogenesis. This rare disorder is characterized by ambiguous genitalia with a normal clitoris, labioscrotal folds, a urogenital sinus and inguinal or intra-abdominal testes microscopically devoid of mature Leydig cells. The diagnosis is made biochemically by the presence of low testosterone and estradiol values with elevated luteinizing hormone levels in the absence of other significant hormonal changes. The clinical and laboratory features of this disorder offer support for human developmental concepts derived from animal models.

Adult↗
PubMed1979

Hypothalamic-pituitary-adrenal function in extrinsic asthma.

Hypothalamic-pituitary-adrenal function in a well-defined, carefully selected group of 25 patients with extrinsic asthma was assessed by measuring plasma levels of adrenocorticotropic hormone (ACTH) and of 11-deoxycorticol after administration of metyrapone and by measuring the level of cortisol following stimulation with cosyntropin. No difference was demonstrated between asthmatic subjects and 20 normal age-matched controls. In addition, neither the response of the level of ACTH nor of 11-deoxycortisol correlated with the duration of asthma or the severity as assessed in 23 patients by tests of pulmonary function. We conclude that there is no abnormality in hypothalamic-pituitary-adrenal function in patients with extrinsic asthma, and we suggest that previous data suggesting such an abnormality may reflect heterogeneous groups of patients, inaccurate methods, and the variability of normal responses to ACTH and stimulation with metyrapone.

17-Hydroxycorticosteroids↗
PubMed1976

Alpha1-antitrypsin deficiency and pancreatic fibrosis.

A 39-year-old woman with homozygous ZZ alpha1-antitrypsin deficiency was found to have pancreatic fibrosis in addition to the recognized pulmonary and hepatic abnormalities. Pancreatic exocrine function was normal but endocrine studies showed glucose intolerance. Pancreatic fibrosis may be another manifestation of alpha1-antitrypsin deficiency.

Adult↗
PubMed1974

Fine-needle aspiration biospy of the thyroid.

Fine-needle thyroid aspiration biopsy has a 20-year history in Scandinavia but has seen little use in North America owing to concern about the dissemination of malignant disease and the more limited use of aspiration cytology in general. We have reviewed our experience with this method in 103 cases, and on the basis of our work and the accumulated evidence of others, believe that the procedure is of considerable practical value with little or no risk to the patients under study.

Acute Disease↗