Why whales are big but not bigger: Physiological drivers and ecological limits in the age of ocean giants.

The largest animals are marine filter feeders, but the underlying mechanism of their large size remains unexplained. We measured feeding performance and prey quality to demonstrate how whale gigantism is driven by the interplay of prey abundance and harvesting mechanisms that increase prey capture rates and energy intake. The foraging efficiency of toothed whales that feed on single prey is constrained by the abundance of large prey, whereas filter-feeding baleen whales seasonally exploit vast swarms of small prey at high efficiencies. Given temporally and spatially aggregated prey, filter feeding provides an evolutionary pathway to extremes in body size that are not available to lineages that must feed on one prey at a time. Maximum size in filter feeders is likely constrained by prey availability across space and time.

Beta-galactosidase deficiency: studies of two patients with prolonged survival.

Two adults with beta-galactosidase deficiency were studied. Differences in a number of beta-galactosidase parameters (pH optima, heat denaturation, NaCl kinetics) were noted between the patients. Differences were also noted in beta-galactosidase electrophoretic mobilities and urinary oligosaccharides; however, there was no complementation in cell fusion studies. It is suggested that these two patients have different primary mutations at the beta-galactosidase locus which are probably structural in nature.

Differential correlates of physical activity in urban and rural adults of various socioeconomic backgrounds in the United States.

STUDY OBJECTIVES: Few studies have analysed the rates and correlates of physical activity in economically and geographically diverse populations. Objectives were to examine: (1) urban-rural differences in physical activity by several demographic, geographical, environmental, and psychosocial variables, (2) patterns in environmental and policy factors across urban-rural setting and socioeconomic groups, (3) socioeconomic differences in physical activity across the same set of variables, and (4) possible correlations of these patterns with meeting of physical activity recommendations. DESIGN: A cross sectional study with an over sampling of lower income adults was conducted in 1999-2000. SETTING: United States. PARTICIPANTS: 1818 United States adults. MAIN RESULTS: Lower income residents were less likely than higher income residents to meet physical activity recommendations. Rural residents were least likely to meet recommendations; suburban residents were most likely to meet recommendations. Suburban, higher income residents were more than twice as likely to meet recommendations than rural, lower income residents. Significant differences across income levels and urban/rural areas were found for those reporting neighbourhood streets, parks, and malls as places to exercise; fear of injury, being in poor health, or dislike as barriers to exercise and those reporting encouragement from relatives as social support for exercise. Evidence of a positive dose-response relation emerged between number of places to exercise and likelihood to meet recommendations for physical activity. CONCLUSIONS: Both income level and urban rural status were important predictors of adults' likelihood to meet physical activity recommendations. In addition, environmental variables vary in importance across socioeconomic status and urban-rural areas.

Complications of colostomy closure.

The records of 83 patients with 85 colostomy closures at Charity Hospital, New Orleans from January 1976 through June 1981 were reviewed. There were 47 complications in 30 patients (36 percent) with no deaths. The material used for anastomosis and fascial closure, the precipitating or underlying disease, the site of colostomy, and the length of operation did not influence the complication rate. The major factor affecting the complication rate was the interval of time from creation of the colostomy to its closure. Those patients who underwent closure after a 90 day interval had a lower overall complication rate than comparison groups with less than a 30 day interval and 30 to 90 day intervals (p less than 0.05). Other factors that appeared to influence the complication rate were as follows: loop colostomies had a lower suture line complication rate than divided colostomies, patients who underwent relaparotomy and closure had a higher complication rate than those whose closures were confined to the colostomy site, and wounds left open or that underwent delayed primary closure had a lower infection rate than wounds closed primarily. Thus, loop colostomies appear to have fewer complications at the time of closure than divided stomas. This is most likely related to the necessity for relaparotomy in some of the patients with divided stomas and the need for minimal mesenteric dissection required for most loop colostomy patients. Divided stomas should still be created if indicated, but when a choice exists, loop colostomies are preferable. Contaminated wounds are best managed with secondary closure or delayed primary closure. Because of the significant difference in complication rates between intervals from formation to closure of a colostomy, all patients should have their colostomies closed only after a minimum of 90 days has elapsed.

Beta-galactosidase deficiency: prolonged survival in three patients following early central nervous system deterioration.

Three adult patients from two families have shown slowly progressive neurologic deterioration since the age of 3 years, associated with profound beta-galactosidase deficiency. Although affected individuals from the two different families differ in degree of intellectual deficit, facial coarseness and spondyloepiphyseal dysplasia, all lack visceromegaly and macular red spots. The diversity of phenotypic expression in these patients and others previously reported suggests the existence of composite genotypes (compound and double heterozygosity).

Long-term storage of tissue samples for cell culture.

The establishment of cultured cell lines from skin biopsies stored at -196 degrees C for periods up to 1 year has been investigated. Attempts to initiate cell cultures from the frozen tissue samples were uniformly successful. There was no alteration in chromosome constitution, morphological appearance, or specific activities of lysosomal enzymes in cells cultured from the stored samples. This process can safeguard against failure of the initial tissue culture and provide an alternate means of storing viable cells when it is impossible or impractical to initiate a cell culture immediately.

Solitary lytic lesion of the skull.

Thyroid carcinoma metastatic to the calvaria may result in a lytic, well-circumscribed lesion the appearance of which necessitates differential consideration of lytic lesions of the skull. The merits of angiography in the study of such lesions are noted. Even in young persons, the possibility of metastasis presenting as a solitary lytic defect in the skull must be kept in mind.