Gastroduodenal mucus gel thickness in patients with Helicobacter pylori: a method for assessment of biopsy specimens

The gastroduodenal mucus layer is considered the primary mucosal protective barrier, especially important in the maintenance of a mucosal pH gradient. Thus, the measurement of the mucus layer thickness in various disease states could advance our understanding of gastroduodenal pathophysiology. We present a novel method for measuring the mucus layer in endoscopic biopsy material and compare layer thickness in Helicobacter pylori (HP)-negative and HP-positive specimens. Endoscopic biopsies were obtained from 17 patients with gastroduodenal mucosa harboring HP and from 15 patients without current HP colonization. The thickness of the mucus layer was measured in fresh specimens by the phase-contrast dark-field microscopy technique. In patients with confirmed HP infection, the thickness of the mucus layer (mean +/- SD) was 0.093 +/- 0.033 mm in duodenal, 0.085 +/- 0.027 mm in antral, and 0.105 +/- 0.033 mm in corporal mucosa. In patients without concomitant HP colonization, the thickness of the mucus gel was 0.162 +/- 0.045 mm, 0.175 +/- 0.067 mm, and 0.161 +/- 0.064 mm in duodenum, antrum, and corpus, respectively. The differences between the means were statistically significant (p less than 0.001 for the duodenal, p less than 0.001 for antral, and p less than 0.01 for corporal mucosa). This study suggests that colonization of the gastroduodenal mucosa by HP impairs the mucus layer covering the surface epithelium. This mucus layer impairment may lead to mucosal injury with subsequent development of inflammation and, possibly, peptic ulcer disease.

Gestational age-specific birthweights of twins versus singletons

In order to more adequately characterize patterns of intrauterine growth retardation in twins, the mean birthweights of all nonanomalous white or black twins born between 24 and 41 weeks of gestation and surviving until discharge over an 11-year period (547 infants) and all similar singletons (19,072 infants) were compared by completed weeks of gestation. Between 24 and 35 weeks of gestation, the mean birthweights for the 547 twins and the 19,072 singletons were comparable and did not consistently differ statistically. From 36 to 41 weeks gestation, however, the difference became large, consistent, and statistically significant for each week at P less than 0.0001. This difference was present among all subgroups of twins, ie, in all males, females, blacks, and whites; it was still evident when the sample was further stratified by both race and sex (black males, white males, black females, white females). These data suggest a pattern of growth retardation in twins compared to singletons which is large, consistent, and statistically significant beginning at 36 weeks gestation. Clinically, these data also suggest the need for ultrasonic examination early in gestation (24-32 weeks) to document normal growth and to provide baseline data, and show the importance of such monitoring later in gestation, specifically after 36 weeks.

Reflection Zernike phase contrast microscope

A novel configuration for a reflection Zernike phase contrast microscope is given that has a height sensitivity of 0.5 A.

Seroprevalence of human immunodeficiency virus infection in a prenatal population at high risk for HIV infection

To determine the seroprevalence of human immunodeficiency virus infection in prenatal patients at high risk for HIV infection we tested 513 women from December 1985 through July 1987 at an inner-city hospital in Atlanta, Georgia. Demographic and HIV risk information was collected from all seropositive women. Twenty-nine (6%) of the 513 women tested were positive for HIV on enzyme-linked immunosorbent assay and Western blot analysis. Twenty-six (90%) of seropositive women gave a history of intravenous drug use. Two (7%) had sexual partners known to have AIDS or AIDS-related complex (ARC), and one (3%) was Haitian. Seropositive women were at remarkable risk for other sexually transmitted diseases. The majority of pregnancies ended in term births. This serosurvey defines an obstetric population with a high seroprevalence, and has stimulated us to institute routine voluntary antepartum screening for HIV.

Diamond vs Beryllium Films for Improving Survivability of Metal Mirrors against X Rays

In this paper, we show the usefulness of diamond films for improving the survivability of thin film metal mirrors against intense x rays. Essentially, the low-Z, high thermal conductivity diamond film acts as an efficient heat sink, thus reducing the temperature in the metal film. A comparison is made between a diamond film and a beryllium film interposed between an aluminum/fused silica mirror. It is shown that at relatively low x-ray fluence, beryllium is somewhat more effective in reducing the aluminum temperature, whereas at high fluence, diamond is more effective.