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Biomedical subjects

H Roels

Publications and source records attributed to H Roels.

205 records · Page 12Linked to original sources
PubMedDate not supplied

Ileal mucosal mononuclear cells in patients with seronegative spondylarthropathy.

In order to study local immunoregulatory mechanisms in patients with seronegative spondylarthropathy and histological evidence of asymptomatic intestinal inflammation, we determined mononuclear cells in distal ileal mucosa with an indirect immunoperoxidase technique using a panel of monoclonal antibodies. The number of intraepithelial lymphocytes in inflamed mucosa was not significantly increased. They carried mainly the suppressor-cytotoxic CD8 marker (greater than 80%), less frequently the helper T cell marker CD4 and lacked the pan T epitope CD3 in greater than 50%. There were no intraepithelial B cells or natural killer cells. The lamina propria lymphocytes were T and B cells, the former being more numerous. Helper T cells were more frequent than suppressor-cytotoxic T cells. There were no alterations in the proportion of T cells in inflamed mucosa. Natural killer cells were scarce. They occurred in small numbers in a minority of cases with gut inflammation and spondylarthropathy and rarely in inflammatory bowel disease. It is concluded that although there is an increase of lamina propria monocytes, there is no immunoregulatory imbalance in the ileal mucosa of patients with seronegative spondylarthropathy.

Adolescent↗
PubMedDate not supplied

M cells are damaged and increased in number in inflamed human ileal mucosa.

Ileocolonoscopy and biopsies of patients with spondylarthropathy revealed gut inflammation in 62% of the cases. In order to better understand the pathogenetic mechanisms of spondylarthropathy related gut inflammation the follicle associated epithelium was examined. Biopsies from 9 controls and 18 patients with spondylarthropathy were studied by electron microscopy. Membranous (M) cells were investigated in normal and inflamed ileum. In normal mucosa M cells were scarce whereas in inflamed mucosa their number was increased (up to 24% of follicle associated epithelial cells). They showed a thin rim of cytoplasm covering groups of lymphocytes. In chronic ileitis necrotic M cells, ruptures of M cell cytoplasm and lymphocytes entering the gut lumen were observed. The bursts of M cells at the top of the lymphoid follicles lead to interruption of the gut epithelial lining and give luminal content access to the lymphoid tissue. This pathogenetic mechanism may cause aphthoid ulcers.

Crohn Disease↗
PubMedDate not supplied

Lead exposure and conventional and ambulatory blood pressure: a prospective population study. PheeCad Investigators.

OBJECTIVE: - To evaluate in a prospective fashion the association between low-level lead exposure and blood pressure. DESIGN: - Prospective cohort study. SETTING: - General population. PARTICIPANTS: - A random population sample (N=728; 49% men; age range, 20-82 years) was studied in Belgium for 1985 through 1989 and reexamined for 1991 through 1995. MEAN OUTCOME MEASURES: - At baseline and follow-up, blood pressure was measured by conventional sphygmomanometry (15 total readings) and at follow-up also by 24-hour ambulatory monitoring. Lead exposure was estimated from blood lead and zinc protoporphyrin concentrations. Multivariate analyses controlled for sex, age, body mass index, smoking and drinking habits, physical activity, exposure at work, social class, menopausal status, use of medications (antihypertensive medication, oral contraceptives, hormonal replacement therapy), hematocrit or hemoglobin, serum total calcium concentration, 24-hour urinary sodium and potassium excretion, and gamma-glutamyltransferase activity. RESULTS: - At baseline, mean (SD) systolic/diastolic conventional blood pressure was 130 (17)/77 (9) mm Hg. The mean blood lead concentration was 0.42 micromol/L (8.7 microgram/dL), and the mean zinc protoporphyrin concentration was 1.0 microgram per gram of hemoglobin. Over the 5.2-year median follow-up, the mean blood lead concentration dropped by 32% (0.14 micromol/L [2.9 microgram/dL]) (P<.001). Small but significant (P<.01) changes occurred in systolic (-1.5 mm Hg) and diastolic (+1.7 mm Hg) conventional blood pressure and in zinc protoporphyrin concentration (+0.5 microgram per gram of hemoglobin). Over the follow-up period, no consistent associations emerged between the changes in conventional blood pressure and in blood lead or zinc protoporphyrin concentrations. In addition, after adjustment for sex, age, and body mass index, blood lead and zinc protoporphyrin concentrations at baseline did not predict the development of hypertension in 47 patients (risk ratio for doubling of the initial lead concentration, 1.2; 95% confidence interval, 0.7-2.0). In a time-integrated analysis in which each person was characterized by all available measurements, conventional blood pressure did not correlate with blood lead or zinc protoporphyrin concentrations in a consistent manner. Similarly, the mean (SD) 24-hour blood pressure at follow-up (119 [11]/71 [8] mm Hg; N=684) did not show a consistent relationship with blood lead or zinc protoporphyrin concentrations at baseline or at follow-up. CONCLUSIONS: - Lead exposure at the intensity studied (<l.45 micromol/L [<30 microgram/dL]) was not consistently associated with increased conventional or 24-hour blood pressure in the general population or with increased risk of hypertension. These findings argue against the hypothesis that current lead exposure levels are associated with excess cardiovascular morbidity and mortality caused by hypertension.

Adult↗