Variation in menstrual cycle length and cessation of menstruation in captive raised baboons

Primatologists have recognized that non-humans undergo the menopause [Biol. Reprod. 68 (2003) 10], which is preceded by years of irregular cycles and decreased fecundity. The similarity of reproductive changes between humans and baboons suggests that the aging female baboon is a particularly promising model to study human menopause and changes that precede it. In an effort to provide an assessment of potential peri-menopausal changes in reproductive function in non-human primates, our goals were to determine if menstrual cycles become more variable with age and to identify the onset of changes consistent with peri-menopause and menopause in baboons. To accomplish these goals, we calculated means and variances for menstrual cycle lengths of females at ages 5, 10, 15, and 20 years and identified onset of menstrual cycle variability (peri-menopause) and cessation of menstruation (menopause). Mean cycle lengths were not significantly different, but significant heterogeneity of variances existed, with younger animals experiencing less variability than older animals. Mean ages of onset for the peri- and menopausal transitions were 18.89 and 26.34 years, respectively. These results provide evidence that captive aging female baboons experience menstrual cycle changes similar to peri- and menopausal women.     

The baboon as a nonhuman primate model for the study of the genetics of obesity

OBJECTIVE: At present, rodents represent the most common animal model for research in obesity and its comorbidities (e.g., type 2 diabetes and coronary heart disease), however, there are several physiological and developmental differences between rodents and humans reflective of their relatively ancient evolutionary divergence (approximately 65 to 75 million years ago). Therefore, we are currently developing the baboon as a nonhuman primate model for the study of the genetics of obesity. RESEARCH METHODS AND PROCEDURES: At present, we are collecting extensive phenotypic data in a large pedigreed colony (N > 2000) of baboons housed at the Southwest Foundation for Biomedical Research in San Antonio, Texas. The long-term goal of this project is to identify genes influencing adiposity-related phenotypes and to test hypotheses regarding their pleiotropic effects on other phenotypes related to increased risk for a variety of common diseases (e.g., coronary heart disease and type 2 diabetes). RESULTS: To date we have obtained various adipose-specific endocrine measures, adipose tissue biopsies, and estimates of body composition on a substantial portion of our pedigreed colony. The pattern of adipose tissue accumulation follows closely that seen in humans, and we have detected significant additive genetic heritabilities for these obesity-related phenotypes. DISCUSSION: Given the physiological and developmental similarities between humans and baboons, along with the ability to collect data under well-controlled situations and the extensive pedigree data available in our colony, the baboon offers an extremely valuable nonhuman primate model for the study of obesity and its comorbidities.     

Searching for genes underlying normal variation in human adiposity

A primary challenge in biomedical research today is the elucidation of the underlying genetic architecture of complex conditions such as obesity. In contrast to simple Mendelian disorders that result from a mutation in a single gene, complex phenotypes are the product of the action (as well as interaction) of multiple genes and environmental factors. The genetic configuration of these genes can range from effectively polygenic (i.e., many genes each with a relatively small contribution) to oligogenic (i.e., a few genes with relatively large measurable effects often expressed on a residual additive genetic background). While the task at hand is complicated, it is not intractable; however, it does require consideration of the nature of the disease and definition of its associated phenotypes in selecting the most appropriate study design. Here we will discuss the characteristics of obesity and its related phenotypes, which must be considered in designing analyses to identify the genes involved as well as reviewing what these approaches have provided in the search for genes influencing adiposity in humans     

Pet sensitivities in asthmatic children

A history of pet contact and/or apparent clinical sensitivity was obtained in 65 (55%) of 118 unselected asthmatic children. These 65 children were skin tested and their sera examined for specific IgE using the radioallergosorbent test. Those children who had apparent clinical sensitivities had larger skin test reactions and were more likely to have positive specific IgE results than those without apparent sensitivities. Positive skin tests were very common (80%), but the larger the skin test reaction (weal diameter greater than 4 mm diameter) the more likely was there to be a positive history or a positive specific IgE result. Hence a large skin test reaction can provide a helpful pointer to animal allergy of clinical importance. Commercially available animal extracts have limitations for diagnostic tests. A questionnaire survey of 150 day schools emphasized the potential opportunities for contact with animal allergens at school.     

COBALAMIN DEFICIENCY and SMALL BOWEL BACTERIAL OVERGROWTH: A COMMON ASSOCIATION

Background  Bacterial overgrowth may cause cobalamin deficiency through competition for dietary cobalamin in the small intestine. The objective of this study was to prospectively determine the prevalence of small bowel bacterial overgrowth in patients with documented cobalamin deficiency in a tertiary referral centre.
Methods  Patients identified with cobalamin deficiency underwent diagnostic investigations including: Endoscopy (with gastric antrum, gastric body and duodenal biopsies and duodenal aspirate), ¹⁴C-D-Xylose breath test, intrinsic factor antibody, anti-endomysial antibody and red cell folate level. 'Definite' small bowel bacterial overgrowth was defined as either a positive ¹⁴C-D-Xylose breath test or > 100 000 CFU/mL of culture of duodenal aspirate. 'Suspected' small bowel bacterial overgrowth was defined as an elevated red cell folate in the absence of supplemental folate therapy.
Results  Over a 2-year period, 62 patients with cobalamin deficiency were identified, of whom, 26 (42%) had 'definite' small bowel bacterial overgrowth, whilst a further nine (15%) had 'suspected' small bowel bacterial overgrowth. Nineteen (31%) had pernicious anaemia, and no cause for cobalamin deficiency could be found in eight (13%) patients. The diagnosis found in the remaining patients included coeliac disease (4), Crohn's Disease (1), gastric resection (2), vegan (2), homozygotes of the MTHFR gene (C677T) mutation (2), and one had enteropathy associated with common variable immunodeficiency (CVID). 'Definite' small bowel bacterial overgrowth was found to coexist with nine of the 19 cases of pernicious anaemia, two coeliac subjects, one CVID enteropathy and one patient with the MTHFR gene mutation.
Conclusion  Small bowel bacterial overgrowth is commonly associated with cobalamin deficiency.     

Pseudomembranes in reflux esophagitis

Three cases are presented in which double-contrast esophagograms revealed one or more plaquelike lesions in the distal esophagus, representing pseudomembrane formation in patients with severe reflux esophagitis. Although to our knowledge this finding has not been reported previously in the radiologic literature, pseudomembranes have been documented endoscopically in patients with reflux esophagitis and biopsy-proved Barrett esophagus. Radiologists should be aware of this finding, since these pseudomembranes may be indistinguishable radiographically from plaquelike carcinomas arising in Barrett esophagus.