Comparison of experimental diabetes induced by streptozotocin and cyproheptadine

It is generally accepted that Diabetes mellitus is caused by the endocrinological functional disturbance of the pancreas, decreasing available insulin for carbohydrate metabolisms. Diabetes mellitus is not necessarily related to hypoinsulinemia, and some senile subjects show diabetic symptoms although the insulin levels in their blood are within the normal range. Therefore, in order to examine the cause of Diabetes mellitus, the glucose tolerance test is usually given as a routine laboratory method to monitor the pancreatic endocrine functions. The pattern of decreasing glucose level in blood will tell us what is the cause of the disease. In testing the effects of anti-diabetic drugs, experimental diabetic conditions have been prepared by various methods, and recently streptozotocin (STZ) and cyproheptadine (CPH) have been successfully used to induce diabetic conditions of various degrees. In the present study, degree of disturbance of the pancreatic functions by STZ and CPH were compared, and in addition, disturbance of organs other than the pancreas was also examined biochemically. When a high dose of STZ was given, irreversible disfunction of glucose level normalizing and insulin secreting abilities was observed. Serum GOT, GPT, lysosomal enzyme activities and lysosomal enzyme activity in the liver and pancreas decreased in high dose STZ administered rats. Low dose STZ disturbed the pancreatic endocrine function less than that in high dose STZ, and the blood glucose level normalizing function was reversibly disturbed. Insulin secretion decreased, and normalized on discontinuation of low dose STZ administration. Low dose STZ also disturbed organs other than the pancreas as in high dose STZ.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differential detection of PAS-positive inclusions formed by the Z, Siiyama, and Mmalton variants of alpha1-antitrypsin

Several point mutations of alpha(1)-antitrypsin cause a perturbation in protein structure with consequent polymerization and intracellular accumulation. The retention of polymers of alpha(1)-antitrypsin within hepatocytes results in protein overload that in turn is associated with juvenile hepatitis, cirrhosis, and hepatocellular carcinoma. The detection of alpha(1)-antitrypsin polymers and understanding the molecular basis of polymer formation is of considerable clinical importance. We have used a monoclonal antibody (ATZ11) that specifically recognizes a conformation-dependent neoepitope on polymerized alpha(1)-antitrypsin to detect polymers within hepatocytes of individuals with alpha(1)-antitrypsin deficiency. Paraffin-embedded liver tissue specimens were obtained from individuals who were homozygous for the Z (Glu342Lys), Mmalton (52Phe del), and Siiyama (Ser53Phe) alleles of alpha(1)-antitrypsin that result in hepatic inclusions and profound plasma deficiency. Immunohistological staining with a polyclonal anti-human alpha(1)-antitrypsin antibody showed hepatic inclusions in all 3 cases, while ATZ11 reacted with hepatic inclusions formed by only Z alpha(1)-antitrypsin. Polymers of plasma M and Z alpha(1)-antitrypsin prepared under different conditions in vitro and polymers of recombinant mutants of alpha(1)-antitrypsin demonstrated that the monoclonal antibody detected a neoepitope on the polymerized protein. It did not detect polymers formed by a recombinant shutter domain mutant (that mirrors the effects of the Siiyama and Mmalton variants), polymers formed by cleaving alpha(1)-antitrypsin at the reactive loop, or C-sheet polymers formed by heating alpha(1)-antitrypsin in citrate. In conclusion, the ATZ11 monoclonal antibody detects Z alpha(1)-antitrypsin in hepatic inclusions by detecting a neoepitope that is specific to the polymeric conformer and that is localized close to residue 342.     

A Difficult Differential Diagnosis of Acute Cholecystitis in a Patient With Steroid-induced Diabetes

An impairment of gallbladder motility due to autonomic neuropathy may cause cholestasis and result in gallbladder stone formation. Diabetes is one of risk factors for acute cholecystitis. Diabetes and steroid use are associated with the susceptibility to bacterial infections, we are apt to diagnose steroid-induced diabetic patients manifesting symptoms of cholecystitis as having acute bacterial infective cholecystitis. Here, we report a very rare steroid-induced diabetic patient complicated with gallbladder torsion-induced necrotizing cholecystitis due to a floating gallbladder. KEYWORDS: Cholecystitis; Diabetes; Floating gallbladder; Torsion.     

Simultaneous resection of liver cell adenomas and an intrahepatic portosystemic venous shunt with elevation of serum PIVKA-II level

A 27-year-old woman with no history of liver disease or oral contraceptive use presented with sudden abdominal pain. Laboratory data showed mild liver dysfunction with jaundice. Computed tomography and angiography revealed centrally located large liver cell adenomas (LCAs) and an intrahepatic portosystemic venous shunt (IHPSS) in the left lobe. The serum des-γ-carboxy prothrombin (known as “protein induced by a lack of vitamin K or antagonist II,” PIVKA-II) level was extremely high (6647 mAU/ml), indicating malignant transformation of the tumors. Under the diagnosis of LCAs and IHPSS, the patient underwent simultaneous resection of the four liver tumors and portovenous shunt, and the hepatic vascular abnormality was resolved. The pathological diagnosis was LCAs without hepatocellular carcinoma. Immunohistochemical analysis with an anti-PIVKA-II monoclonal antibody showed positive staining of the adenoma cells. This case shows that LCA without malignant transformation can produce PIVKA-II, leading to high serum levels of PIVKA-II. Simultaneous resection of multiple tumors and closure of the portosystemic shunt are strongly recommended in a patient with LCA associated with IHPSS.     

Induction of human neutrophil chemotaxis by Candida albicans-derived beta-1,6-long glycoside side-chain-branched beta-glucan

Polysaccharide beta-1,3-D-glucans (beta-glucans) are components of the cell wall of various fungi and show immunomodulatory activities. beta-Glucans have been reported to enhance neutrophil accumulation during pathogenic fungi-induced lung inflammation. Therefore, we examined whether beta-glucans themselves possess chemotactic activities for human neutrophils. Among several kinds of beta-glucans, beta-1,6-long glucosyl side-chain-branched beta-glucan, isolated from Candida albicans [Candida soluble beta-D-glucan (CSBG)], dose-dependently induced neutrophil migration in a Boyden chamber system. In contrast, 1,6-monoglucosyl-branched beta-glucans, such as Sparassis crispa-derived beta-glucan (SCG) and grifolan (GRN), which were derived from nonpathogenic fungi, hardly induced neutrophil migration. Moreover, CSBG-induced neutrophil migration was inhibited completely by liposomes containing neutral glycosphingolipid lactosylceramide (LacCer; Galbeta1-4Glc-ceramide) but not NeuAcalpha2-3Galbeta1-4Glcbeta1-1'-Cer ganglioside. Furthermore, binding experiments demonstrated that CSBG bound to glycosphingolipids (such as LacCer) with a terminal galactose residue; however, SCG and GRN (1,6-monoglucosyl-branched beta-glucans) did not bind to LacCer. It is important that a Src kinase inhibitor protein phosphatase 1, a phosphatidylinositol-3 kinase (PI-3K) inhibitor wortmannin, and a Galpha(i/o) inhibitor pertussis toxin inhibited neutrophil migration toward CSBG. Taken together, our results suggest that beta-1,6-long glucosyl side-chain-branched beta-glucan CSBG binds to LacCer and induces neutrophil migration through the activation of Src family kinase/PI-3K/heterotrimeric G-protein signal transduction pathways.     

Recruitment of the elderly into a pharmacologic prevention trial: the Ginkgo Evaluation of Memory Study experience

The difficulty involved in recruiting healthy older adults into clinical trials, especially those involving pharmacologic agents, is an important issue in research. The Ginkgo Evaluation of Memory (GEM) Study, a double-blind, placebo-controlled randomized clinical trial evaluating Ginkgo biloba to prevent dementia, successfully recruited 3072 participants age 75 years and older at four U.S. sites from September 2000 through June 2002. Using targeted mailing lists, an estimated 243,400 study brochures were mailed out to potential participants. Subsequent attempts were made to reach 14,603 households by telephone, from which 12,186 (83.4%) successful contacts were made. Overall, telephone or in-person evaluations identified 2149 (17.6%) ineligible persons for cognitive (20.6%), medical (49.4%), or other (30.0%) reasons. A total of 6944 (57.0%) refused participation resulting in 3072 enrolled into the study, a recruitment rate of 25.2% based on telephone contacts made or 1.3% of all mailed brochures. Recruitment rates were stable over the 21-month enrollment period but were higher for the two urban centers than the two rural ones. Recruitment was dependent most on mailing lists available, density of older adults in the catchment areas, and Institutional Review Board restrictions. Men and persons under age 85 were more likely to enroll. Primary reason for refusals involved lack of interest (48.4%) or self-perceived poor health (16.2%). Over 9% were unwilling to give up current Ginkgo supplementation or would not accept assignment to placebo. An additional 7% did not want another medication and almost 4% had care-giving responsibilities which prevented involvement. Mass mailings were the most successful approach for recruitment at all four sites and the method through which the vast majority of interviewees had learned about the study. Information on the experience of the GEM Study recruitment may be helpful to other clinical trials attempting to randomize older adults into prevention trials.     

Immunologic reconstitution following bone marrow transplantation for X-linked hyper IgM syndrome

X-linked hyper IgM syndrome (XHIM), caused by mutations of the CD40 ligand (CD40L) gene, is characterized by recurrent bacterial and opportunistic infections, an increased incidence of autoimmunity and malignancies, and immunodeficiency due to abnormal T/B cell interaction. Because of poor long-term prognosis, bone marrow transplantation (BMT) has been proposed as an alternative treatment. An 8-month-old boy with XHIM and a splice site mutation of CD40L underwent BMT using a fully matched sibling donor. Markers of engraftment and immunologic reconstitution were measured serially. After BMT, activated T cells expressed functional CD40L, and genomic DNA obtained from circulating white cells contained predominantly wild-type CD40L sequences. Serum immunoglobulin levels including IgE and antibody responses to recall antigens normalized, and immunization with the T-cell-dependent neoantigen, bacteriophage φX174, demonstrated amplification of the response and isotope switching. BMT provides a permanent cure for XHIM if a fully matched sibling donor is available and the procedure is performed before complications have occurred.     

Is the site of action of grayanotoxin the sodium channel gating of squid axon?

An attempt was made to elucidate the site of action of grayanotoxin (GTX) in the nerve membrane by using various endopeptidases. The experiment was conducted on squid axons isolated from Doryteuthis bleekeli with both voltage clamp and internal perfusion methods. Intracellular application of various endopeptidases for more than 30 min eliminated the gating action from both Na current and K current systems. When GTX (100 microM) was subsequently applied to the internal medium, the membranes could depolarize to various extents. This finding strongly suggests that the site of action of GTX is not confined to the channel gating but is present in a part of the Na channel having both voltage sensor and ion filter functions. With the application of trypsin, St. fradiae trypsin, pronase, BPN', and St. fradiae protease (group B), GTX-induced depolarization was much smaller than that with the application of alpha-chymotrypsin, N-protease, and thermolysin (group A). The difference in the sensitivity to GTX between group A and group B became remarkable as the time for application of the enzymes was prolonged. Since all enzymes belonging to group B retain trypsin-like activity and are more effective in removing the sensitivity to GTX, it is suggested that the molecular moiety around the binding site of GTX is rich in basic amino acids or the essential part for opening the Na channel should be protected by basic amino acids.     

LIGHT AND ELECTRON MICROSCOPIC OBSERVATIONS OF THE MYOCARDIUM OF DOGS IN HEMORRHAGIC SHOCK

Morphologic change of the myocardium of the dog were observed in oligemic and normovolemic shock produced by Wiggers' standard method.
Subendocardial hemorrhages, usually superficial and located mostly in the ventricular aspect of the septum, were remarkable in the normovolemic shock group, but rare in the oligemic shock group. The zonal lesion appeared in the early period of oligemic shock becoming more apparent with lapse of time. Ultrastructural studies revealed some differences of the findings of the zonal lesion between oligemic and normovolemic shock. In oligemic shock, the zonal lesion was identical to the supercontraction of myofilaments and dislocation of mitochondria. Supercontraction of myofibrils was usually unilateral, and herniation of damaged myocytes was frequently noticed in the unilateral lesion. In the normovolemic shock, supercontracted areas near the intercalated disc were usually stretched and the myofilaments became irregular in arrangement. In addition, the accumulation of glycogen granules and presence of clear flocculent areas were observed in the cytoplasm of some myocardial cells.
Cell edema, swelling and destruction of mitochondria and contraction bands were found in the damaged myocyte, especially in the terminal stage of normovolemic shock. Swelling of the capillary endothelial cell was already observed in the early period of oligemic shock. In addition, the pathogenesis of the zonal lesion and the mechanism of cardiac depression in hemorrhagic shock were discussed.