Preliminary screening of Chinese herbal medicine in inhibiting Helicobacter pylori

At present Helicobacter pylori (HP) was taken to be closely related to chronic atrophic gastritis and peptic ulcer. 226 patients with symptoms of upper digestive tract by endoscope were examined and chronic atrophic gastritis and peptic ulcer were diagnosed. Mucous membrane from gastric antrum was taken and cultured, and found that 136 cases of 226 patients were HP positive and the rate of positiveness was 60.18%. 200 kinds of Chinese herbal medicine were selected to investigate its inhibitory action on HP. Results indicated that 38 among 200 kinds of Chinese herbal medicine had inhibitory effects on HP, which provided evidence for diagnosis and treatment of chronic atrophic gastritis and peptic ulcer, also for inhibition of HP growth.     

Prolongation of survival of skin allograft with anti-Thy-1 monoclonal antibody in mice

Skin allograft rejection is mainly mediated by T lymphocytes. We investigated the cytotoxicity of anti-Thy-1 McAb to murine thymocytes in vitro, and evaluated the prolonging effect on the survival of murine skin allografts (BALB/c--C57BL/6) in vivo with the McAb. The results showed murine thymocytes were destroyed in vitro by the McAb with complement; the survival of skin allograft was prolonged in vivo with the McAb. Lymphocyte infiltration in skin allografts was inhibited. These results provide a valuable reference for the clinical usefulness of anti-CD3 McAb in prolonging survival of human skin allografts in burn patients.     

Acute effects of bovine growth hormone on renal calcium and phosphate excretion

To evaluate the acute effects of bovine growth hormone upon renal hemodynamics and urinary electrolyte excretion, clearance studies were performed in intact and thyroparathyroidectomized dogs, receiving either vehicle alone or bovine growth hormone. Growth hormone had no effect when compared to controls upon glomerular filtration rate, renal plasma flow, or clearance of sodium, calcium, and phosphate either in the presence or absence of parathyroid hormone. It is concluded that acute changes in circulating growth hormone levels do not play an important role in calcium and phosphate homeostasis. The data suggest that previously described antiphosphaturic and hypercalciuric actions of growth hormone are not due to direct acute renal tubular effects but may be the result of indirect effects of chronic growth hormone administration.     

A conserved negative regulatory region in alphaPAK: inhibition of PAK kinases reveals their morphological roles downstream of Cdc42 and Rac1

AlphaPAK in a constitutively active form can exert morphological effects (E. Manser, H.-Y. Huang, T.-H. Loo, X.-Q. Chen, J.-M. Dong, T. Leung, and L. Lim, Mol. Cell. Biol. 17:1129-1143, 1997) resembling those of Cdc42G12V. PAK family kinases, conserved from yeasts to humans, are directly activated by Cdc42 or Rac1 through interaction with a conserved N-terminal motif (corresponding to residues 71 to 137 in alphaPAK). alphaPAK mutants with substitutions in this motif that resulted in severely reduced Cdc42 binding can be recruited normally to Cdc42G12V-driven focal complexes. Mutation of residues in the C-terminal portion of the motif (residues 101 to 137), though not affecting Cdc42 binding, produced a constitutively active kinase, suggesting this to be a negative regulatory region. Indeed, a 67-residue polypeptide encoding alphaPAK83-149 potently inhibited GTPgammaS-bound Cdc42-mediated kinase activation of both alphaPAK and betaPAK. Coexpression of this PAK inhibitor with Cdc42G12V prevented the formation of peripheral actin microspikes and associated loss of stress fibers normally induced by the p21. Coexpression of PAK inhibitor with Rac1G12V also prevented loss of stress fibers but not ruffling induced by the p21. Coexpression of alphaPAK83-149 completely blocked the phenotypic effects of hyperactive alphaPAKL107F in promoting dissolution of focal adhesions and actin stress fibers. These results, coupled with previous observations with constitutively active PAK, demonstrate that these kinases play an important role downstream of Cdc42 and Rac1 in cytoskeletal reorganization.