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Biomedical subjects

J K Davidson

Publications and source records attributed to J K Davidson.

At least 37 records · Page 2Linked to original sources
PubMed1988

Effect of insulin immune complexes on human blood monocyte and endothelial cell procoagulant activity.

Insulin antibodies and immune complexes (ICs) are present in most patients with diabetes after initiation of conventional insulin therapy. We studied the ability of bovine insulin, porcine insulin, and human insulin ICs to stimulate the procoagulant activity (PCA) of human blood monocytes (HBMs) and human umbilical vein endothelium (HUVE) in vitro. Polyclonal insulin antibodies from patients with insulin antibody-mediated resistance were isolated by immunoabsorption. PCA expressed by isolated adherent HBMs or cultured HUVE was quantified by radioimmunoassay of fibrinopeptide A with a 1:80 dilution of human plasma. Beef, pork, and human insulin, in quantities determined from titration curves, were added to fixed amounts of antibody to obtain equivalent amounts of ICs. For four different antibodies, the ratios of PCA (expressed by HBMs exposed to ICs or to antibodies alone and normalized for cell numbers) to activity expressed by tissue culture medium were as follows: beef insulin ICs, 2.55 +/- 0.41; por insulin ICs, 1.47 +/- 0.16; human insulin ICs, 1.28 +/- 0.19; and antibody, 1.28 +/- 0.32. The differences between beef and pork insulin ICs and antibody controls were significant. For a fifth antibody, a dose response between beef insulin ICs and PCA expression was demonstrated. For a sixth antibody, HBMs could express PCA when stimulated with antibody of a relatively low binding capacity (0.35 ng bovine insulin per microgram of antibody) only in the presence of lymphocytes. Conditioned medium from these cells significantly stimulated endothelial cell procoagulant activity. These observations raise the possibility that insulin ICs, that is, beef insulin ICs, may generate increased PCA and thereby contribute to the vascular complications of diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Digital filtering of the bladder in SPECT bone studies of the pelvis.

A data processing technique for the removal of bladder activity from single photon emission computed tomographic bone studies of the pelvis has been developed. The method involves the replacement of count values in the bladder on all projection views by data which are representative of the activity in surrounding structures. Reconstruction is then performed using the amended set of projection views. The method was tested by examining a group of 13 patients referred for investigation of avascular necrosis of the femoral head. Significant improvements in image quality were observed, particularly with respect to the level of artifact production, which increased the number of cases in which a confident and correct diagnosis was made.

Femur Head Necrosis↗
PubMed1987

False localization of an aldosteronoma by dexamethasone-suppressed adrenal scintigraphy.

A patient with primary aldosteronism had bilateral adrenal tumours on computed tomography. Selenocholesterol scintigraphy showed uptake by the larger right adrenal gland and a tumour in the gland was also visualized by venography. In contrast, measurements of aldosterone concentrations in adrenal venous blood lateralized to the left side. At surgery the left adrenal gland contained an aldosteronoma and the right adrenal gland a large non-functioning adenoma. Thus, selenocholesterol scintigraphy incorrectly localized the functioning adrenal tumour.

Adenoma↗
PubMed1987

Rapid decrease of insulin-specific IgG antibody levels in insulin-dependent patients transferred to semi-synthetic human insulin.

A multicenter, open trial was designed to examine the efficacy and safety of semi-synthetic human insulin (SSHI; Novolin R and Novolin L, SQUIBB-NOVO) in patients with insulin-dependent diabetes mellitus who were transferred from other commercially-available insulins. Whether such a change in therapy would reduce circulating IgG antibodies to antibovine insulin was also evaluated. A total of 68 males and females, 8-62 yr of age, were maintained on their original insulin therapy for 4 weeks, when both glycosylated hemoglobin and fasting blood glucose were assessed. IgG antibody titers to antibovine insulin were also measured. All patients were then transferred to SSHI for a period of 20 weeks. The same variables were evaluated at Weeks 2, 4, 8, and 20. Mean fasting blood glucose levels rose monotonically from 189-226.3 mg/dl over the course of the 20-week clinical trial. There was a slight but insignificant increase in glycosylated hemoglobin by the end of the test period. The average value for antibovine insulin IgG antibodies decreased from 2.54 mu/ml at baseline to 1.32 mu/ml by the completion of the trial. Significant decreases were first observed 4 weeks after the patients were placed on SSHI therapy. After transfer to SSHI, 43.3% of the patients achieved some improvement in glycemic control and only 16.4% were worse than at baseline. A decrease in weekly hypoglycemic reactions occurred during the course of the SSHI therapy. It appears that SSHI provides safe and effective treatment for insulin-dependent diabetic patients and that its use results in a rapid and significant decrease in insulin antibody formation.

Adult↗
PubMed1986

Enhancing relationships: understanding the feminine mystique of pretending orgasm.

As individuals become increasingly aware of their sexuality and orgasmic responsiveness, concomitantly, the phenomenon of pretending orgasm is becoming a greater part of the sexual relationship for many couples. However, few studies exist concerning this phenomenon despite the fact that nearly two-thirds of all females have reported pretending orgasm. Therefore, the purpose of this study was to profile those females who have pretended orgasm by examining the dimensions of their sexual and orgasmic behaviors, the factors that inhibit their orgasm, the dynamics of partner interaction, and any desired changes in their sexual lives. A survey research design was employed utilizing the responses of 805 professional nurses who participated in a study concerning self-perceptions of the female sexual response. The findings indicate that those females who have ever pretended orgasm became sexually active at a younger age and have been more sexually explorative than those females who have not pretended orgasm. Furthermore, the role of their sex partners was a significant dimension in their orgasmic pretense. The resultant impact on coupled relationships has many critical implications for therapists.

Adult↗
PubMed1986

Coitally active university students: sexual behaviors, concerns, and challenges.

The past fifteen years, in particular, have seen a major increase in the extent to which both adolescents and young adults are engaging in sexual intercourse. While several studies call attention to the increasing incidence among college/university students, the concomitant shifts in the sociopsychological realms of sexuality are also important dimensions which impact upon sexual concerns of youth. Hence, the purposes of this study are to examine the behaviors, attitudes, and concerns of students who have engaged in coitus, as well as any changes they seek in their sex lives. The sample consisted of 123 never-married male and 205 never-married female undergraduate students from a state university. The data were obtained by utilizing an anonymous questionnaire administered to volunteers during regular university classes. Among the coitally active, 67.4% of males were psychologically satisfied after their first sexual experience, but only 28.3% of females. In contrast, 80.9% of males and 28.3% of females reported current psychological satisfaction with their sexual experiences. Significant differences between genders focused on male dissatisfaction with infrequent opportunities for sexual intercourse, lack of variety of sex partners, and insufficient oral-genital stimulation, whereas females expressed concerns relating to lack of stimulation to their breasts, painful sexual intercourse, lack of orgasm during sexual intercourse, and feelings of guilt and fear. An increasing awareness of current sexual behaviors, attitudes, and concerns of university students can help family life educators to meet student needs as they react to changes in interpersonal relationships, families, and society.

Adolescent↗
PubMed1986

Biliary tract dilatation in acquired immune deficiency syndrome.

Biliary tract dilatation without obstruction may result from sclerosing cholangitis, pyogenic cholangitis, or bile duct surgery. This case report describes a patient with AIDS whose biliary tract dilatation was due to cytomegalovirus infection. Such a diagnosis should now be considered in the immuno-suppressed patient who has dilated bile ducts.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Osteonecrosis and fractures following renal transplantation.

Skeletal radiological surveys in 161 renal transplant recipients identified 36 patients with 115 lesions of osteonecrosis. A further two patients with osteonecrosis found at autopsy had had no radiographic abnormality. The total incidence of osteonecrosis was, therefore, 38 (24%) out of 161. The lesions were frequently multiple and bilateral with structural failure being the most common initial abnormality and the femoral head the most frequent site. Lesions also occurred in the femoral condyles, the talus, the humeral heads and the metatarsals, many being symptom-free. Calcification was demonstrated in the femoral and tibial shafts. The initial radiological abnormality appeared at a mean interval of 19 months after transplant but could occur as late as 75 months. Significantly fewer patients, three (7%) out of 41, developed osteonecrosis following a low-dose prednisolone regimen (0.8 g) compared with a high-dose group (2.8 g) where 35 (29%) out of 120 were affected. More females than males developed osteonecrosis, but no correlation could be demonstrated with regard to age, primary renal disease, number and type of transplant and duration of dialysis prior to transplant. Osteonecrosis is a complication which can be reduced with a low-dose prednisolone regimen. Most lesions will be demonstrated by radiological survey undertaken during the second and fourth years after transplantation.

Adolescent↗
PubMed1985

Malignant phaeochromocytoma.

Malignant phaeochromocytoma is a rare tumour and experience in its management is therefore limited. Five patients are discussed in whom the development of metastases was associated with rapidly progressive disease.

Adrenal Gland Neoplasms↗
PubMed1982

Skeletal effects of orthovoltage and megavoltage therapy following treatment of nephroblastoma.

A review of 19 patients treated for nephroblastoma between 1945 and 1978 by nephrectomy and radiotherapy with chemotherapy showed a marked improvement in cure rate in recent years. In the decade from 1950 to 1960 there are four survivors. From 1960 to 1970, there are nine survivors from 25 cases and since 1970 there are 19 survivors from 27 cases. Skeletal effects of radiation therapy have been reviewed in 22 patients--seven of whom had orthovoltage and 15 megavoltage therapy. Similar skeletal changes followed both orthovoltage and megavoltage therapy, being more severe after the adolescent growth spurt and when the follow-up was longer. The radiation dose was normally 3000 cGy and skeletal changes followed the lowest dose of 2200 cGY. Scoliosis of the lumbar spine, concave to the side of the tumour, with angulation ranging from less than 5 degrees to 54 degrees developed in 12 patients; all but one showed asymmetry of the body LV2. Kyphosis was present in three patients; anterior beaking of the vertebral body in 10; and 16 patients showed asymmetry of more than one vertebral body. Iliac hypoplasia was present in 19 patients, being unilateral when only the renal bed was irradiated. Analysis of the radiological changes expressed as a total score against the age at follow-up shows that severe changes follow orthovoltage therapy. It is too early to assess the full extent of megavoltage therapy simply because patients have not been followed up for a comparable length of time.

Adolescent↗
PubMed1981

Pre-operative localization of aldosterone-secreting adrenal adenomas.

Techniques for pro-operative localization of aldosterone-secreting adrenal adenomas were studied in thirty-seven patients, each with hypertension and biochemical evidence of primary hyperaldosteronism and each later having adrenal surgery (thirty-two adenomas, five bilateral hyperplasia). Bilateral adrenal vein catheterization was attempted in all cases; it was successful on the left side in all patients and in 92% of cases on the right. Adrenal vein plasma samples were obtained from the left side in 92% and from the right in 73% of cases. Adrenal vein plasma aldosterone measurements correctly indicated the presence of tumour in twenty-eight cases but falsely predicted unilateral adenoma in two cases of bilateral adrenal hyperplasia. Adrenal venography also correctly predicted unilateral adrenal adenomas in twenty-six cases but falsely suggested the presence of tumour in three cases of bilateral adrenal hyperplasia. Computed tomography (CT) was used in the last eight cases. In seven instances the predictions (six adenomas, one bilateral adrenal hyperplasia) were confirmed at surgery. However, the remaining patient harboured an adenoma 20 mm in diameter which was not detected by CT although diagnosed both by adrenal venography and adrenal vein aldosterone measurements. Ultrasound detected adenoma in only three of twenty-two cases examined. Although further comparative studies of the type described here are required, the results of computed tomography are promising and suggest that this non-invasive technique might well become the first choice procedure in localizing aldosterone-secreting adenomas.

Adenoma↗