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Biomedical subjects

D C Mayes

Publications and source records attributed to D C Mayes.

8 recordsLinked to original sources
PubMed2000

Crohn's disease, pregnancy, and birth weight.

OBJECTIVE: Although there is general agreement that conception should be avoided when Crohn's disease is active, many questions remain unanswered for the woman with Crohn's disease in remission who becomes pregnant. METHODS: Sixty-five charts of women with Crohn's disease quiescent at the start of pregnancy were identified between January 1993 and December 1997. Each pregnancy was matched to a healthy control pregnancy by date, age, parity, smoking status, and gestational age +/- 1 wk, and comparisons were carried out using matched analyses. RESULTS: The two groups were similar in terms of maternal height, weight, and body mass index (BMI), in addition to the matched variables. The incidence of pregnancy complications was similar for most of the complications examined, whereas the incidence of poor maternal weight gain differed significantly between the groups (17/65 vs 2/65, p < 0.001). Flare-up of the Crohn's disease was seen in 13/65 (20%) of pregnancies. The greatest differences in neonatal outcomes were in terms of birth weight (3150+/-80 g vs 3500+/-60 g) and birth weight percentile (36.7%+/-.6% vs 57.5%+/-3.4%). Overall, there were 16 (24.6%) small for gestational age (SGA) births in the Crohn's group, compared with only one (1.5%) in the control group (p = 0.0007). Multivariate analysis was performed to identify factors predictive of SGA births in the Crohn's group. Ileal Crohn's disease was a statistically significant predictor (p = 0.035), whereas previous bowel resection trended toward statistical significance (p = 0.065). CONCLUSIONS: In view of the risk of low birth weight, all women with Crohn's disease who become pregnant should be followed carefully during the pregnancy, particularly those who have ileal disease or who have previously undergone bowel resection. Furthermore, smoking cessation needs to be aggressively pursued in these patients.

Adult↗
PubMed2000

Maternal smoking and preeclampsia.

OBJECTIVE: To study the relationship between maternal smoking and preeclampsia and whether this association differs between primiparous and multiparous women. STUDY DESIGN: We conducted a population-based, retrospective, cohort study of 58,216 singleton pregnancies from northern and central Alberta, Canada, between 1995 and 1997. Multivariate logistic regression was used to control for maternal alcohol consumption, drug dependence, maternal age, maternal weight, prior intrauterine growth restriction and other confounders. RESULTS: Maternal smoking was associated with a significantly reduced overall risk of preeclampsia (adjusted odds ratio [aOR]: .61; 95% confidence interval [CI]: .50-.75; P < .01). Stratified analyses showed that in primiparous pregnancies, maternal smoking was associated with a significantly decreased risk (aOR: .63; 95% CI: .50-.80; P < .01); in multiparous women, maternal smoking was not associated with a statistically significant decreased risk of preeclampsia (aOR: 0.72; 95% CI: .51-1.02; P > .05). CONCLUSION: Maternal smoking is protective against preeclampsia. Understanding the underlying biologic mechanisms of this protective effect may advance our knowledge of the pathogenesis of preeclampsia.

Adolescent↗
PubMed1999

Tonometry to estimate intestinal perfusion in newborn piglets.

AIM: To determine the correlation between gastric intramucosal pH and superior mesenteric artery (SMA) flow in newborn piglets. METHODS: Fourteen newborn piglets were randomly assigned to either a control or to an epinephrine group which received 0,1,2,4,0 microg/kg/min of epinephrine for 60 minutes, each dose. Gastric tonometry was performed, SMA flow was measured, and intramucosal pH and the ratio of tonometer pCO(2) over arterial pCO(2) (rCO(2)) were calculated. RESULTS: Intramucosal pH decreased over time in both groups, but tended to be lower in the epinephrine group. With increasing dose of epinephrine, SMA flow decreased; this in turn increased rCO(2) (p = 0.04) with a tendency to decrease intramucosal pH (p = 0.06). CONCLUSIONS: Gastric tonometry may be useful in human neonates to evaluate gut ischaemia.

Animals↗
PubMed1990

Renal liposarcoma.

A liposarcoma arose in the kidney of a 52-year-old man. After 13 years, it recurred, was resected, and recurred again. The second recurrence was inoperable.

Cell Nucleus↗
PubMed1985

Dietary fat and immune function. II. Effects on immune complex nephritis in (NZB x NZW)F1 mice.

(NZB x NZW)F1 mice initiated on fat restriction at weanling were significantly protected from the development of immune complex glomerulonephritis. Whereas the mice on high-fat intake demonstrated immune depositions both in capillary walls and mesangial areas in a diffuse granular pattern, those on a low-fat diet with caloric content similar to the high-fat diets exhibited mesangial confinement of the depositions of immunoglobulins, complement, and retroviral gp70. In association with these divergent patterns of immune deposition, the mice on high-fat diets had evidence of extensive diffuse cellular proliferation, wire loop lesion, and sclerosis in the glomeruli. In contrast, most of the mice on the low-fat diet showed only mesangial cell and matrix proliferations. In addition, the group of mice fed high saturated fat showed more severe glomerular pathology as compared to those fed high unsaturated fat. Paradoxically, levels of circulating immune complexes (as measured by the polyethylene glycol precipitation technique) in the high saturated fat group were low and did not correlate with the findings by light and immunofluorescence microscopy. These findings suggest that dietary fat restriction can serve as either a prophylactic or effective therapeutic approach to murine lupus nephritis.

Animals↗
PubMed1985

Inhibition of humoral immunity in vivo by monoclonal antibody to L3T4: studies with soluble antigens in intact mice.

Monoclonal antibody (MAb) to the mouse "helper" T cell antigen L3T4 inhibits the T cell response to class II major histocompatibility antigens on antigen-presenting cells in vitro and in thymectomized mice. To examine the effect of MAb to L3T4 on humoral immunity in euthymic mice, we treated BALB/c mice with 1 mg of anti-L3T4 i.p. at the time of immunization with either bovine serum albumin (BSA) or chicken egg ovalbumin (OA) in complete Freund's adjuvant. Administration of MAb to L3T4 selectively depleted greater than 90% of L3T4+ cells from the blood, spleen, and lymph nodes, but it had little effect on thymocytes. Mice treated with anti-L3T4 were unable to generate an IgG response to either BSA or OA. Treatment with anti-L3T4 also prevented the antigen-specific IgM response to these antigens, although it did not prevent nonspecific stimulation of IgM anti-BSA and anti-OA antibodies induced by adjuvant in the absence of antigen. Humoral immunity was inhibited even when treatment was delayed until 48 hr after immunization. These findings indicate that T cell help for humoral immunity can be abrogated in intact mice by MAb to L3T4.

Animals↗