P Palmiter-Thomas | PubMed Health

PubMed1996

How forearm position affects grip strength.

OBJECTIVE: Several studies have indicated that changing body positions results in altered grip strengths. Although one might expect that grip strength would be influenced by the position of the forearm during gripping due to the biomechanical properties of the forearm and hand muscles, no investigations of this variable have been undertaken. METHOD: This study examined the effect on grip strength of moving the forearm among supinated, neutral, and pronated positions while maintaining the standard position recommended by the American Society of Hand Therapists. The mean of three grip trials in each position was recorded for each of 106 subjects. RESULTS: Grips in forearm supination were the strongest, followed by grips in the neutral position. Grips in pronation were the weakest. CONCLUSIONS: The changes in grip strength observed with variations in forearm position further support the necessity of a standard position for testing grip strength. The knowledge of how changes in body position affect the strength of the grip can be used to design environments and tools to maximize biomechanical abilities.

Adolescent↗

PubMed1992

High molecular weight secretory products of the human pancreatic ductal epithelium and the effect of secretin on their discharge.

Principal cells of the pancreatic ductal epithelium have been reported to secrete high molecular weight (HMW) glycoconjugates such as mucins into the ductal lumen. We used a human pancreatic carcinoma cell line of ductal origin (PANC-1) which has retained some of the morphological and biochemical characteristics of normal ductal principal cells as a source for isolation of HMW secretory products. The present study was designed to isolate these HMW secretory products, partially characterize them through biochemical and immunological approaches, and determine the effects of secretin on their synthesis and discharge from PANC-1 cells. Our results indicated that when PANC-1 cells are grown on collagen-coated beads in defined serum-free medium, at least three HMW secretory products could be isolated from the medium. These secretory products had a mass of approximately 200, 280, and 370 kDa based on sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis. The 200-kDa species made up proportionally less of the three in the gel-staining pattern. Polyclonal antibodies raised to the 370-kDa secretory product cross-reacted with the 280-kDa species. The 370-kDa secretory product was sulfated and wheat germ agglutinin (WGA) binding indicated that the 370-kDa species was a glycoconjugate. The 280-kDa and 200-kDa species were sulfated to a much lesser degree than the 370-kDa species and WGA binding could not be clearly demonstrated with the 280 kDa or 200 kDa species. Glycosidase and selective degradation studies, however, indicated that all three species contained glycosaminoglycan moieties. Antibodies raised to the 370-kDa secretory product localized to the epithelium of human pancreatic carcinomas but not to other cell types in this neoplastic tissue. The antibody also cross-reacted with the ductal epithelium of normal human pancreas and could be localized to centroacinar cells, the epithelium of intralobular ducts, and the epithelium of interlobular ducts. The antibody did not cross-react with goblet cells of the human small or large intestine, indicating no generalized reactivity to gastrointestinal mucins. ELISA and pulse-chase immunoprecipitation studies indicated an increase in the cellular content and synthesis of these HMW secretory products after stimulation of PANC-1 cells with 10(-8)- to 10(-11)-M secretin. We correlated secretin stimulation with the appearance of numerous membrane bound vesicles throughout the cytoplasm as monitored at the ultrastructural level. Optimal secretin concentration were in the range of 10(-10) M. The content of these vesicles was immunoreactive to the antibody raised against the 370-kDa secretory product as determined by ultrastructural immunocytochemical techniques.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1990

Metal ions induce expression of metallothionein in pancreatic exocrine and endocrine cells.

Northern blot hybridization established that metallothionein (MT) mRNA levels were dramatically elevated in the rat pancreas following injection of Cd or Zn salts. To determine which pancreatic cell types express the MT gene, Northern blot hybridization analysis of RNA from preparations enriched for acini, in situ hybridization, and immunocytochemistry were used. RNA from pancreatic acini of Zn-treated rats contained high levels of MT mRNA. In control rats, in situ hybridization suggested very low levels of MT mRNA in both exocrine and endocrine cells in the pancreas, but these levels were dramatically increased in both these cell populations following metal injection. In contrast, levels of insulin-I mRNA in the endocrine cells were not affected by metal injection. A similar result with MT mRNA was obtained in mouse and chicken pancreas using Northern blot and in situ hybridization. Immunocytochemistry detected MT in the rat acinar cell cytoplasm following metal injection. Although inconsistent with in situ hybridization studies and immunocytochemical analysis of exocrine cells, immunocytochemistry for MT indicated a uniform staining pattern of islet cells that was unaffected by metal treatment. These results establish that metal ion induction of the MT genes in pancreas occurs in both endocrine and exocrine cells, which suggests that this protein has diverse physiologic functions in this organ.

Animals↗