EFFECT OF MICROSTRUCTURE ON HYDROGEN DAMAGE OFJBK-75 PRECIPITATE-STRENGTHENED AUSTENITIC STEEL

1.IntroductionHydrogenembrittlement(HE)0rhydr0gendamage(HD)ofall0ysisnotonlyrelatedt0chemicalc0mpositionsbutals0c10selyt0microstructures.Thereweres0merep0rts0ntheeffect0fmicr0structures0nHD0fsingle-phaseausteniticsteels[1-3].Themicrostructuralreas0nsofHD0fprecipitate-strengthenedausteniticsteels(PSAS),however,havereceivedlessattenti0n.Single-phaseausteniticsteelshaveproveninseveralinstancestohaveg00dresistancet0HD,butaretypicallynostr0ngerthan450MPainyieldstrength.Thus,anausteniticmatri…     

The asystolic donor syndrome: transaminitis and thrombocytopenia after non-heartbeating renal transplantation

BACKGROUND: The use of kidneys from non-heartbeating donors (NHB) remains controversial. An increased incidence of delayed primary function and primary nonfunction is common. We report a characteristic syndrome of transaminitis and thrombocytopenia after NHB renal transplantation, which may be predictive of graft outcome. METHODS: Two case histories are presented, followed by a retrospective analysis of 38 NHB renal grafts performed at Guy's Hospital from 1988 to 1994. Changes in alanine aminotransferase (ALT) and platelet count were compared between recipients of kidneys from NHB and heartbeating donors (HB). To control for possible effects of antilymphocyte globulin (ALG), two matched control groups receiving HB kidneys with (n=32) and without (n=32) ALG were also compared. RESULTS: ALT was elevated in 32 of 38 (84%) of NHB recipients and 19 of 64 (30%) controls (P<0.001). Mean peak ALT was 172+/-20 U/L in NHB and 42+/-6 U/L in HB kidneys (P<0.001). Use of ALG did not influence mean peak ALT. Elevated ALT predicted impaired graft function (P<0.02) and was associated with an increased length of delayed primary function (P<0.001) and risk of transplant nephrectomy (P<0.05). Thrombocytopenia (<100 x 10(9) cells/L) occurred in 18 of 38 (47%) NHB recipients and in 20 of 64 (31%) controls (P<0.05). Mean nadir platelet count (x 10(9) cells/L) was 113+/-10 in NHB, 128+/-9 in HB with ALG, and 164+/-9 in HB without ALG (both P<0.05 vs. NHB). Patients who underwent graft nephrectomy (n=9) had a disproportionate fall in platelet count (mean nadir, 80+/-11 x 10(9) cells/L; P<0.05). CONCLUSIONS: Transaminitis and thrombocytopenia occur commonly after NHB kidney transplantation and are predictive of graft outcome. Recognition of these changes may assist the early management of NHB renal recipients, and also reduce investigation of "anomalous" results in this setting.     

Novel systemically active antagonists of the glycine site of the N-methyl-D-aspartate receptor: electrophysiological, biochemical and behavioral characterization

A series of novel tricyclic pyrido-phthalazine-dione derivatives was tested for antagonistic effects at the strychnine-insensitive modulatory site of the N-methyl-D-aspartate (NMDA) receptor (glycineB). All compounds displaced [3H]MDL-105,519 binding to rat cortical membranes with IC50 values of between 90 nM and 3.6 microM. In patch-clamp experiments, steady-state inward current responses of cultured hippocampal neurons to NMDA (200 microM, glycine 1 microM) were antagonized by these same compounds with IC50 values of 0.14 to 13.8 microM. The antagonism observed was typical for glycineB antagonists, i.e., they induced desensitization and their effects were not use or voltage dependent. Moreover, increasing concentrations of glycine were able to decrease their apparent potency. Much higher concentrations (>100 microM) were required to antagonize alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-induced currents. They were potent, systemically active NMDA receptor antagonists in vivo against responses of single neurons in the rat spinal cord to microelectrophoretic application of NMDA with ID50 values in the low milligram per kilogram i.v. range. They also inhibited pentylenetetrazol-, NMDA- and maximal electroshock-induced convulsions in mice with ED50 values ranging from 8 to 100 mg/kg i.p. The duration of anticonvulsive action was rather short but was prolonged by the organic acid transport inhibitor probenecid (200 mg/kg). The agents tested represent a novel class of systemically active glycineB antagonists with greatly improved bioavailability.     

Results of the double stapling procedure in colorectal surgery

In this report we review our results with the double stapling technique (DST) in 162 patients with colorectal diseases in an attempt to identify some of the potential pitfalls of this new technique. Among these 162 patients, there were 125 patients with colorectal cancer, 25 with chronic ulcerative colitis (UC), 9 with familial adenomatous polyposis (FAP), 2 with adult Hirschsprung's disease, and 1 with sigmoid colon fistula. A total of 46 anastomoses (28 for rectal cancer, 13 for UC, 3 for FAP, and 2 for adult Hirschsprung's disease) were performed at or near the dentate line. Of these, 10 had protective diverting colostomy or ileostomy. The results showed that 6 patients with rectal cancer had anastomotic leakage (3.7%); however, 4 of the 6 patients had also received preoperative irradiation. All the leaks healed after the patients had undergone diverting colostomy, but 7 patients with rectal cancer suffered from neurogenic bladder postoperatively (4.3%). Wound infection occurred in 4 patients (2.5%), anastomotic bleeding in 3 (1.9%), and anal pain in 1 (0.6%), respectively. One patient with rectal cancer and multiple liver metastases died of disseminated intravascular coagulation (DIC). These results thus suggest that the double stapling technique provides a safe anastomosis at or near the dentate line not only for rectal cancer but also for UC, FAP, and adult Hirschsprung's disease.     

Induction of tolerance to human gamma-globulin in FcR gamma- and Fc gammaRII-deficient mice

FcR gamma-deficient mice were used to examine the role of Fc gamma receptors in the induction of peripheral tolerance to human gamma-globulin (HGG). FcR gamma-deficient mice injected with HGG in adjuvant demonstrated a CD4+ T cell response to in vitro challenge with HGG, as assayed by proliferation, cytokine secretion, and Ag-specific help for B cell Ab production. In vitro kinetics of Ag-specific proliferation were similar in both conventional and knockout mice. Peripheral tolerance could be established in these mice with a single dose of deaggregated protein, despite the lack of functional Fc gammaRI, the high affinity receptor for monomeric IgG. Establishment of unresponsiveness was observed at both the T and B cell levels. T cell tolerance was manifested in the reduction of T cell helper function and Ag-induced release of Th1- and Th2-like cytokines, as well as decreased proliferation to Ag-specific stimulation. B cell tolerance was demonstrated in knockout and normal mice by failure to detect HGG-specific Ab production using an immunization protocol for Ab production that bypasses the need for Ag-specific T cells. These results demonstrate that induction of tolerance in CD4+ cells to HGG does not require transduction of a signal through Fc gammaRI. Furthermore, the ability to induce tolerance to HGG in B cells in Fc gammaRII-deficient mice suggests that down-regulation of Ag-specific B cells through Fc gammaRII is not the mechanism by which B cell tolerance is induced. However, Fc gammaRII plays a role in regulating the immune response since the Ab response to immunogenic HGG in Fc gammaRII-deficient mice is markedly enhanced.     

9-Benzyladenines: potent and selective cAMP phosphodiesterase inhibitors

A 6-year-old Quarter Horse gelding with acute onset of a grade-4/5 lameness of the left forelimb 21 days after an encounter with a porcupine was examined. Quills had been removed by the referring veterinarian, and the horse had been treated with antibiotics and hydrotherapy for 14 days. The horse was pyretic and had effusion in the digital synovial sheath. Signs of pain were elicited on palpation of the area. A tentative diagnosis of septic tenosynovitis caused by a porcupine quill was made. Exploratory tenoscopy revealed large amounts of fibrin in the sheath and a 1.2-cm quill. Bacteriologic culture of synovial fluid yielded a pure growth of Staphylococcus aureus. The horse improved dramatically after tenoscopic removal of the quill, debridement of fibrin, and lavage to dilute inflammatory mediators and bacteria, debridement of fibrin, discovery and removal of a quill, and complete evaluation of the sheath for prognostic purposes. Tenoscopy can provide a means for direct observation and enhance the ability of clinicians to debride a septic synovial sheath in a minimally invasive manner.     

Area V1 in macaque monkeys projects to multiple histochemically defined subdivisions of the inferior pulvinar complex

To investigate how visuotopic connections relate to chemoarchitecture of the inferior pulvinar (PI) complex in macaques, neuroanatomical tracers were placed into known portions of the visual representation in V1. Separate foci of label associated with both the upper and lower visual quadrants occupied neurochemically defined medial, central, lateral, and lateral-shell subdivisions, PIM, PIC, PIL, and PIL-S. Visuotopic connection patterns thus supported the concept of a larger PI that includes portions of three classically defined 'nuclei' [C. Gutierrez, A. Yaun and C.G. Cusick, Neurochemical subdivisions of the inferior pulvinar in macaque monkeys, J. Comp. Neurol., 363 (1995) 545-562.], and corresponds to the topographically organized V1 projection zone.