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Biomedical subjects

J McDonald

Publications and source records attributed to J McDonald.

At least 127 records · Page 7Linked to original sources
PubMed1993

Lupus and pregnancy studies.

OBJECTIVE: To examine factors prior to pregnancy in patients with systemic lupus erythematosus (SLE) that are prognostic for the occurrence of active disease during and shortly after pregnancy. METHODS: Case-control study of pregnant SLE patients and nonpregnant SLE controls, using logistic regression analyses to assess the role of prepregnancy disease activity as a prognostic factor for flare during pregnancy or the postpartum followup period. RESULTS: Lupus flares occurred frequently and in similar percentages of pregnant SLE patients and control SLE patients. Active lupus at study entry, both in control and in pregnant patients, was not predictive of flare. Inactive lupus at onset was not protective against flare in controls but was protective in pregnant lupus patients. CONCLUSION: Inactive disease at the onset of pregnancy in SLE provides optimum protection against the occurrence of flare during pregnancy.

Adrenal Cortex Hormones↗
PubMed1993

Age and follicular phase estradiol are better predictors of pregnancy outcome than luteinizing hormone in menotropin ovulation induction for anovulatory polycystic ovarian syndrome.

OBJECTIVE: To examine the relationship of baseline and preovulatory serum E2, P, and LH levels and age with pregnancy outcome in polycystic ovarian syndrome (PCOS) patients undergoing hMG ovulation induction. DESIGN: Retrospective analysis of all available data over 2 years. SETTING: Tertiary referral ovulation induction clinic. SUBJECTS: Forty-four anovulatory PCOS patients with 25 ovulatory nonconception and 50 conception cycles after hMG ovulation induction. MAIN OUTCOME MEASURES: Ovulation (midluteal serum P > 25 nmol/L [7.86 ng/mL]); pregnancy (serum beta-hCG > 30 mIU/mL 16 days after ovulating injection); pregnancy outcome: pregnancy termination < 20 weeks' or > or = 20 weeks' amenorrhea. RESULTS: Of the endocrine parameters considered, none was significantly different in nonconceptive and conceptive ovulatory cycles. Miscarriage was associated with low basal serum E2: median value for pregnancies ending < 20 weeks, 105 pmol/L (28.6 pg/mL) and for > or = 20 weeks 150 pmol/L (40.9 pg/mL). It was also significantly associated with age. For patients > 29.5 years of age, (29.5 years, population mean age) a baseline E2 < or = 140 pmol/L (38.2 pg/mL) had sensitivity 92%, specificity 54%, positive predictive value 65%, and negative predictive value 87% for the prediction of miscarriage. The nature of the previous cycle, the day of the cycle on which therapy commenced, and a past history of miscarriage were not related either to pregnancy outcome or to basal serum E2.

Abortion, Spontaneous↗
PubMed1993

An open study of luteinizing hormone releasing hormone agonists in infertile women with uterine fibroids.

Twenty infertile women with fibroids were treated with luteinizing hormone releasing hormone agonists (LHRHa) to investigate if the use of these drugs, both with and without myomectomy, was effective in contributing to pregnancy in these women. All women had fibroids as their sole cause for infertility. Seven women conceived within 1 year of myomectomy or LHRHa treatment alone without myomectomy. The overall pregnancy rate was 36% and the postmyomectomy pregnancy rate was 50%. Initial fibroid size and extent of fibroid shrinkage on LHRHa therapy made no difference to the subsequent pregnancy rate. We also found no significant interaction between the number of fibroids present and the effect of myomectomy on the proportion of pregnancies. We conclude that the fertility enhancing value of myomectomy in otherwise idiopathic infertility is confirmed, and that the use of LHRHa premyomectomy in infertile women needs to be investigated in randomized controlled trials to assess its value as a preoperative therapy.

Adult↗
PubMed1993

The (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium) colorimetric assay for the quantitation of Actinobacillus pleuropneumoniae cytotoxin.

Using swine neutrophils as target cells, two MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium) colorimetric assay systems, one with and one without phorbol 12-myristate 13-acetate (PMA) stimulation were established for the quantitation of Actinobacillus pleuropneumoniae cytotoxin. The MTT assays were optimized for the number of neutrophils, incubation time, and PMA concentration by a series of experiments. The optimal conditions were 25 x 10(4) cells/well incubated for four hours for the assay system without PMA stimulation, and 12.5 x 10(4) cells/well incubated for two hours for the assay system with PMA stimulation. One culture supernatant of a toxigenic Pasteurella multocida strain and five A. pleuropneumoniae cytotoxin preparations produced from three A. pleuropneumoniae strains were used to test assay reproducibility. Results showed both assays were reproducible with a coefficient of variation ranging from 7.8 to 18% for the assay system without PMA stimulation and from 10.7 to 18.2% for the assay system with PMA stimulation. The PMA-stimulated assay had 40 to 60-fold higher sensitivity than the nonstimulated MTT assay. The MTT assay also was applied to the measurement of neutralizing antibody titers against A. pleuropneumoniae cytotoxin.

Actinobacillus pleuropneumoniae↗
PubMed1993

Actinobacillus pleuropneumoniae culture supernatants interfere with killing of Pasteurella multocida by swine pulmonary alveolar macrophages.

The effect of Actinobacillus pleuropneumoniae culture supernatant on swine pulmonary alveolar macrophage (PAM) functions was studied. The A. pleuropneumoniae culture supernatant was toxic to PAMs when tested by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and lactate dehydrogenase (LDH) release assays. Biological activity of the supernatant was ascribed to cytotoxins. Both the LDH and MTT assays were used for measurement of crude A. pleuropneumoniae cytotoxin concentration with good reproducibility. A preparation containing 6,800 toxic units/mL (determined by MTT assay) was used for subsequent experiments. The objective was to study the effect of crude cytotoxin on the ability of swine PAMs to kill Pasteurella multocida. Phagocytosis of opsonized P. multocida type A by PAMs was not efficient. Only 8% of incubated organisms were ingested by noncytotoxin-treated PAMs after 30 min phagocytosis. The bactericidal effect of noncytotoxin-treated PAMs only last for 60 min, after which, the rate of growth of surviving P. multocida exceeded the rate of bacterial killing by PAMs. Complete elimination of P. multocida by PAMs was not observed in this study. A total loss of ability to kill P. multocida by PAMs was seen when the PAMs were pretreated with a high concentration (340 toxic units/mL) of A. pleuropneumoniae cytotoxin. If the PAMs were pretreated with a low concentration (3.4 toxic units/mL) of cytotoxin, a significant reduction in the killing of P. multocida was still observed. The reductions in phagocytosis, phagosome-lysosome fusion (demonstrated using yeast particles of Candida albicans), and oxidative burst (demonstrated by nitro blue tetrazolium reduction (NBT) assay) may have contributed to the impaired killing of P. multocida by PAMs.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus pleuropneumoniae↗
PubMed1992

Body weight, body mass index, and age: predictors of menotropin dose and cycle outcome in polycystic ovarian syndrome?

Whereas the dose of hMG is significantly correlated with both BMI and BW, commencing the more obese patient on higher hMG doses is not justified in view of the cancellation of cycles from over-responsiveness in the more obese patients started on higher hMG dosage regimens. If the more obese patient is slow to respond, however, a greater degree of clinical freedom may be exercised to increase the dose. The ultimate outcome of the cycle is not related to BMI, BW, or the dose of hMG used.

Aging↗
PubMed1992

Contrast nephropathy in patients with impaired renal function: high versus low osmolar media.

Prescription of low osmolar contrast to prevent nephrotoxicity in subjects with pre-existing renal impairment is costly and has not been clearly shown to be effective. We entered 249 subjects with a pre-contrast serum creatinine greater than 120 mumol/liter (1.35 mg/dl) having cardiac catheterization or intravenous contrast into a randomized controlled trial comparing high and low osmolar contrast. The outcome assessed was a rise in serum creatinine repeated 48 to 72 hours after contrast. A further 117 patients entered the non-randomized prospective arm of the study. In the randomized study the serum creatinine rose by at least 25% after contrast in 8 of 117 (6.8%) given high and in 5 of 132 (3.8%) given low osmolar contrast (P greater than 0.05, one-tailed 95% confidence interval for the difference 3 to 7.8%). More severe renal failure (greater than 50% increase in serum creatinine) after contrast was uncommon (3.4% with high and 1.5% with low osmolar contrast). A rise in serum creatinine after contrast was significantly associated with the severity of the pre-contrast renal impairment and the presence of diabetes mellitus, but not with type of contrast. Diabetics with a serum creatinine greater than 200 mumol/liter (2.25 mg/dl) pre-contrast had a highest risk of deterioration in renal function after contrast. We conclude that in patients with pre-existing renal impairment the incidence of contrast nephropathy was not significantly different comparing high osmolar and nonionic contrast. The potential benefit of nonionic contrast in moderate renal impairment is likely to be small, but trials in diabetics with severe renal impairment should be undertaken urgently.

Aged↗
PubMed1992

Peripheral vascular disease in patients with systemic lupus erythematosus.

Patients with systemic lupus erythematosus may develop premature atherosclerosis, notably coronary artery disease. A group of 10 patients with peripheral vascular disease presenting with intermittent claudication or gangrene were studied from a group of 563 patients followed prospectively at the Wellesley Hospital Lupus Clinic. These 10 patients were compared with the next lupus clinic patient matched for age and sex, with respect to demographic characteristics and risk factors. The patients and controls did not differ significantly in lupus activity criteria count, partial thromboplastin time, the number with antibody to cardiolipin, number receiving steroids or mean steroid dose, family history of atherosclerosis, hyperlipidaemia, smoking, hypertension or use of oral contraceptives. The risk factors for developing peripheral vascular disease were a longer duration of systemic lupus erythematosus and a longer duration of use of steroids. Eight of the 10 patients had coexistent coronary artery disease or transient ischaemic attack.

Adult↗
PubMed1991

A maximum likelihood procedure for the analysis of group and individual data in aphasia research.

The limitations inherent in group versus case studies appear to lie in a complementary distribution, underscoring the importance of combining both strategies within a single research program. However, this compromise approach requires analytic tools that permit us to combine and evaluate individual and group data in a common format. Maximum likelihood estimation (MLE) belongs to a family of procedures for determining goodness of fit. MLE can be used in conjunction with a linear or nonlinear model of the way that sources of information combine to determine a given behavioral outcome; such models can be used to estimate the distance between two groups, the degree to which an individual case deviates from a given empirically or theoretically defined group profile, and the degree to which one individual case resembles another. We offer a demonstration of how MLE can be used to evaluate group and individual profiles, in a cross-linguistic study of sentence comprehension in nonfluent aphasic speakers of English, Italian, and German. This includes a demonstration in which the MLE models for each language are "lesioned" to simulate several competing accounts of receptive agrammatism.

Aphasia↗