Pancreatic beta-cell-specific targeted disruption of glucokinase gene. Diabetes mellitus due to defective insulin secretion to glucose

Mice carrying a null mutation in the glucokinase (GK) gene in pancreatic beta-cells, but not in the liver, were generated by disrupting the beta-cell-specific exon. Heterozygous mutant mice showed early-onset mild diabetes due to impaired insulin-secretory response to glucose. Homozygotes showed severe diabetes shortly after birth and died within a week. GK-deficient islets isolated from homozygotes showed defective insulin secretion in response to glucose, while they responded to other secretagogues: almost normally to arginine and to some extent to sulfonylureas. These data provide the first direct proof that GK serves as a glucose sensor molecule for insulin secretion and plays a pivotal role in glucose homeostasis. GK-deficient mice serve as an animal model of the insulin-secretory defect in human non-insulin-dependent diabetes mellitus.

Cloning and expression of murine high molecular mass heat shock proteins, HSP105

We have shown that the 105-kDa heat shock protein (HSP105) and the 42 degrees C-specific heat shock protein (42 degrees C-HSP) constitute high molecular mass heat shock proteins. To elucidate the structure of these heat shock proteins, we have screened a cDNA library constructed with poly(A)+ RNA derived from mouse FM3A cells preheated at 42 degrees C for 2 h using an antibody against murine HSP105. Two full-length cDNA clones were obtained: the pB105-1 insert encoded an 858-amino acid protein, and the pB105-2 insert encoded an 814-amino acid protein and lacked 44 amino acids found in pB105-1. The two clones contained the amino acid sequence found in the 17-kDa polypeptide fragments from HSP105 and 42 degrees C-HSP by lysylendopeptidase digestion. In vitro translation products of the RNA transcripts from pB105-1 and pB105-2 migrated to the same positions of HSP105 and 42 degrees C-HSP, respectively, on SDS-polyacrylamide gel electrophoresis. Northern blot analysis showed that the transcript was approximately 4 kilobases in murine FM3A cells and was strongly induced by heat shock and by treatment with arsenite or an amino acid analog. By reverse transcription-polymerase chain reaction analysis using primers by which deletion of 132 nucleotides in pB105-2 could be detected, the polymerase chain reaction product corresponding to pB105-2 was increased only after heat shock at 42 degrees C, whereas the product corresponding to pB105-1 was induced by heat shock at either 42 or 45 degrees C and also by other stresses. Thus, the cDNA clones pB105-1 and pB105-2 encode HSP105 and 42 degrees C-HSP, respectively, and HSP105 and 42 degrees C-HSP (a short form of HSP105) are suggested to be produced by alternative splicing. Here, HSP105 and 42 degrees C-HSP are renamed HSP105 alpha and HSP105 beta, respectively. A protein sequence homology search revealed that HSP105 shares 54, 34, and 25% amino acid identity with human HSP70RY, the sea urchin egg receptor for sperm, and murine inducible HSP70, respectively. Furthermore, by Northern blot analysis, HSP105 mRNA was revealed to be present in most murine tissues and to be highly expressed in the brain.

Localization, trafficking, and temperature-dependence of the Aequorea green fluorescent protein in cultured vertebrate cells

The localization, trafficking, and fluorescence of Aequorea green fluorescent protein (GFP) in cultured vertebrate cells transiently transfected with GFP cDNA were studied. Fluorescence of GFP in UV light was found to be strongest when cells were incubated at 30 degrees C but was barely visible at an incubation temperature of 37 degrees C. COS-1 cells, primary chicken embryonic retina cells, and carp epithelial cells were fluorescently labeled under these conditions. GFP was distributed uniformly throughout the cytoplasm and nucleus independent of cell type examined. When GFP was fused to PML protooncogene product, fluorescence was detected in a unique nuclear organelle pattern indistinguishable from that of PML protein, showing the potential use of GFP as a fluorescent tag. To analyze both function and intracellular trafficking of proteins fused to GFP, a GFP-human glucocorticoid receptor fusion construct was prepared. The GFP-human glucocorticoid receptor efficiently transactivated the mouse mammary tumor virus promoter in response to dexamethasone at 30 degrees C but not at 37 degrees C, indicating that temperature is important, even for function of the GFP fusion protein. The dexamethasone-induced translocation of GFP-human glucocorticoid receptor from cytoplasm to nucleus was complete within 15 min; the translocation could be monitored in a single living cell in real time.

[The internal thoracic artery of poor quality: was cardiac massage a cause of ITA stenosis?]

The case of stenotic left internal thoracic artery (LITA), with a very rare and interesting histological findings is reported. The patient, a 65-year-old man, fell into shock, due to acute myocardial infarction and received cardiopulmonary resuscitation at home immediately. Three months later, patient underwent coronary artery bypass grafting. The LITA was dissected from the chest wall with a tissue pedicle by usual manner. However, it was abandoned to use for grafting, because of extremely poor blood flow even after balloon dilatation was noticed. Histological study revealed a significant granulation of LITA media, led to severe stenosis of LITA lumen on it's portion. On other side, either proximal and distal portion of LITA remained intact. It seems that this unusual histological change of LITA media developed after LITA over stretching due to cardiac massage during cardiopulmonary resuscitation. If patient, scheduled for coronary bypass surgery, has in a personal history the presence of cardiac massage, traffic accident, some contact sport or any other chest trauma, it is recommended to perform LITA angiography preoperatively, if an intention to use the LITA for coronary artery bypass grafting exists.

Preoperative disseminated intravascular coagulation (DIC) associated with aortic aneurysm--does it need to be corrected before surgery?

Disseminated intravascular coagulation (DIC) is one of the complications accompanying aortic aneurysm. We herein report four patients with aortic aneurysm who had DIC preoperatively. In all four cases, DIC was corrected immediately after surgery; however, in two cases, DIC could not be corrected preoperatively. This prompted us to reconsider the importance of correcting DIC before surgery. Of the four cases reported in this paper, DIC existed even at the time of surgery in two cases, in spite of meticulous treatment with heparin and/or protease inhibitor; however, the DIC could be removed postoperatively even in these two cases. Surgeons should not waste time with intensive DIC treatment preoperatively. If the DIC cannot be corrected within more than 2 weeks of meticulous treatment, surgeons should then perform surgery on the patient. In addition, it is also essential to ensure that the DIC is due to the aneurysm itself and that no other disease processes have been overlooked.

Detection of anti-cord factor antibodies in intestinal tuberculosis for its differential diagnosis from Crohn's disease and ulcerative colitis

We have developed a diagnostic method for pulmonary tuberculosis by detecting antibody to cord factor using enzyme-linked immunosorbent assay (ELISA). This study was to evaluate the usefulness of our method for a diagnosis of intestinal tuberculosis, and especially its ability to differentiate this disease from other inflammatory bowel diseases. Antibodies of the immunoglobulin G class against cord factor (trehalose-6,6'-dimycolate) from 27 patients with intestinal tuberculosis, 16 patients with Crohn's disease (CD), and 27 patients with ulcerative colitis (UC) were tested by ELISA with cord factor purified from Mycobacterium tuberculosis H37Rv as the antigen. Twenty-three of the 27 patients with intestinal tuberculosis (85%) showed elevated values distinct from healthy controls. None of the patients with CD showed an elevation of antibody titers. Of the 27 patients with UC, 26 (96%) did not show any anti-cord factor antibody elevation. We conclude that this method is simple and results are reproducible. The results of our study justify undertaking the detection of anti-cord factor antibodies to diagnose intestinal tuberculosis.

The location of the paths subserving micturition: studies in patients with cervical myelopathy

Urodynamic studies and neurological examinations were performed on 128 patients with cervical myelopathies including 82 with spondylitic myelopathy and 46 with ossification of the posterior longitudinal ligament (OPLL), investigating the location of the paths subserving micturition in the spinal cord. Accurate history taking revealed micturitional symptoms in 95 patients, including irritative symptoms in 61 and obstructive symptoms in 71. Urinary incontinence was noted in 25 and residual urine of over 100 ml or retention was found in 22. Neurological examination revealed disturbed deep sensation in 55, disturbed superficial sensation in 63 and pyramidal signs (weakness, hyperreflexia of legs and Babinski sign) in 96 patients. Urodynamic studies revealed uninhibited contraction in 61 and detrusor-sphincter dyssynergia in 22 patients. Bladder capacity was smaller in patients with Babinski sign (P < 0.05) and in patients with uninhibited contraction (P < 0.001). Uninhibited contraction was more frequent in patients with all three of the above-mentioned pyramidal signs (P < 0.05). Detrusor-sphincter dyssynergia was more frequent in patients with disturbed deep sensation (P < 0.05) and pyramidal signs (P < 0.05, P < 0.0005). From above results and our previous findings in patients with anterior spinal artery syndrome and with tabes dorsalis, it is concluded that the pathway subserving detrusor function seems to be located mainly in the lateral column of the spinal cord. The descending pathway subserving coordination of bladder and urethral sphincter seems to be located mainly in the lateral column, and its ascending pathway seems to be located in the dorsal column. The path subserving urinary sensation seems to be located mainly in the dorsal column of the spinal cord.

[Management of polypoid lesions of the gallbladder by endoscopic ultrasonography (EUS)--a retrospective study to establish the diagnostic criteria and a prospective study to evaluate its reliability]

The diagnostic criteria of endoscopic ultrasonography (EUS) in the management of polypoid lesions of the gallbladder was established by a retrospective study using 57 cases with polypoid lesions of the gallbladder that were all resected and confirmed histologically. By this study, EUS findings of polypoid lesions of the gallbladder were classified into the following six groups; Type I with a foamy high echogram, Type II with a globular high echogram, Type III with a papillary high echogram, Type IV with a papillary solid echogram, Type V with a nodular solid echogram and Type VI with a nodular solid echogram including multiple spotty an-echoic areas which suggested the presence of Rokitansky-Aschoff sinus. Comparing the types of EUS findings with histological diagnosis, Type I and II corresponded to cholesterol polyps. Type III and IV contained benign pseudo tumors such as cholesterol polyp or hyperplastic polyp as well as tumorous lesions such as adenocarcinoma or adenoma. Type III with over 10 mm in size and IV with over 5 mm in size had a possibility of tumorous lesions. Type V usually corresponded to adenocarcinoma, and Type VI to adenomyomatous hyperplasia. From these results, the following criteria was established; (1) Polypoid lesions showing Type I, II, III with less than 10 mm in size, IV with less than 5 mm in size and VI should be followed-up as benign diseases. (2) Polypoid lesions of Type III with over 10 mm in size and IV with over 5 mm in size was considered to be relative indications for surgery as tumors. (3) Polypoid lesions of Type V was an absolute surgical indication as malignant. The reliability of this EUS criteria was followingly evaluated by a prospective study using 94 cases with polypoid lesions of the gallbladder; 32 cases with open or laparoscopic cholecystectomy and 62 cases with over one year follow-up observations. The criteria corresponded well with the histological or follow-up findings in Type I, II, III with less than 10 mm in size, IV with less than 5 mm in size, V and VI. It had, however, a tendency of over indications to surgery in Type III with over 10 mm in size and IV with over 5 mm in size because these types were widely set not to overlook tumorous lesions such as adenoma and small adenocarcinoma.(ABSTRACT TRUNCATED AT 400 WORDS)

Graft site morbidity with autogenous semitendinosus and gracilis tendons

To distinguish between morbidity caused by harvesting semitendinosus and gracilis tendons and morbidity associated with anterior cruciate ligament reconstruction surgery, we performed a prospective randomized study using 65 patients who underwent anterior cruciate ligament reconstruction using these tendons. The patients underwent either contralateral (N = 34) or ipsilateral (N = 31) graft harvest. For the nonoperated knees in the ipsilateral harvest group, isometric and isokinetic strength of the quadriceps and hamstring muscles increased to approximately 120% of the preoperative value at 12 months after surgery. Compared with these knees, the tendon harvest did not affect quadriceps muscle strength at all. However, harvest did decrease hamstring muscles strength for 9 months after surgery. The graft harvest in the knees with anterior cruciate ligament reconstruction also did not significantly affect quadriceps muscle strength, but it did significantly decrease hamstring muscles strength only at 1 month. Activity-related soreness at the donor site was rarely restricting and resolved by 3 months. This study demonstrated that the semitendinosus and gracilis tendon graft is a reasonable choice to minimize the donor site morbidity in ligament reconstruction using autografts.

Inhibition of aldosterone turn-off phenomenon following chronic adrenocorticotropin treatment with in vivo administration of antiglucocorticoid and antioxidants in rats

Chronic adrenocorticotropin (ACTH) treatment in rats leads to a fall in aldosterone secretion (aldosterone turn-off or "aldosterone escape" phenomenon) with a concomitant rise in corticosterone. To elucidate whether ACTH-induced aldosterone suppression is mediated by steroid type II receptor or related to a free-radical effect by over-synthesized corticosterone, we examined the effects of a glucocorticoid antagonist, RU486, and antioxidants dimethyl sulfoxide (DMSO) and vitamin E, on the aldosterone turn-off phenomenon in rats. Each rat received daily for 5 days a different dose of ACTH-Z (5, 10, 20 or 40 micrograms/100 g body weight) 1 mg RU486/100 g body weight, 100 microliters (1.3 mmol) DMSO/100 g body weight or 2 mg vitamin E/100 g body weight with subcutaneous injection. Plasma steroid levels and in vitro release of steroids from the adrenal capsule were measured. The ACTH-Z treatment caused a dose-dependent increase in corticosterone and a decrease in aldosterone in both plasma and adrenal capsule experiments, as well as an increase in adrenal weights. For the following study 5 micrograms/100 g body weight of ACTH-Z was used. Administration of RU486 alone caused no change in plasma aldosterone level compared to controls, even though the steroid type II receptor was blocked, as evidenced by significant increases in plasma ACTH and corticosterone levels. Concomitant administration of RU486 and ACTH-Z increased both plasma corticosterone and aldosterone levels (p < 0.01) but decreased adrenal capsule corticosterone production (p < 0.05) compared to the rats treated with ACTH-Z alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C virus genotypes and development of hepatocellular carcinoma

BACKGROUND

Among several genotypes of hepatitis C virus (HCV), genotypes 1b (or II) and 2a (or III) are predominant in Japan. Although it has been shown that the efficacy of interferon treatment of patients with chronic hepatitis C varies with the HCV genotype, the relationship between HCV genotype and the development of hepatocellular carcinoma (HCC) has not been well described.

METHODS

The genotypes and serum levels were determined for HCV-RNA in 72 patients with HCC and 131 patients without HCC, all of whom were positive for second-generation HCV antibody and HCV-RNA. In addition, clinical data from 34 patients with HCC who each had a history of blood transfusion were analyzed.

RESULTS

Fifty-seven (79.2%) of 72 patients with HCC had genotype 1b HCV, whereas 101 (77.1%) of 131 patients without HCC had genotype 1b, indicating that there was no significant difference in the prevalence of genotype 1b HCV between the patients with and without HCC. Furthermore, comparison of patients with HCC with genotype 1b HCV with those with genotype 2a who had a history of blood transfusion did not differ significantly in the number of years from blood transfusion to diagnosis of HCC. Levels of HCV-RNA were not significantly different among patients with liver diseases of various stages.

CONCLUSIONS

Hepatocellular carcinoma develops in patients with either genotype 2a HCV or genotype 1b HCV. A difference in genotype is not likely to be responsible for the difference in development of HCC.

A mutation in the beta 3-adrenergic receptor gene is associated with obesity and hyperinsulinemia in Japanese subjects

The Trp 64 Arg mutation in the beta 3-adrenergic receptor (beta 3AR) gene was investigated in 350 Japanese subjects. This mutation was not associated with non-insulin-dependent diabetes mellitus (NIDDM). In 191 subjects without NIDDM, body mass index (BMI) was significantly higher in subjects homozygous for this mutation than in those homozygous for the normal allele (24.7 +/- 1.4 vs 22.1 +/- 0.2 kg/m2, p = 0.009). Moreover, the frequency of the mutant allele in obese subjects (BMI > 26.4) was significantly higher than that in non-obese subjects (BMI < 22) (0.37 vs 0.15, p = 0.009). The presence of this mutation was also accompanied by significantly higher fasting (p = 0.000) and 2 hrs (p = 0.018) serum insulin levels during an oral glucose tolerance test. The beta 3AR may be one of the loci contributing to obesity and hyperinsulinemia/insulin resistance in Japanese subjects.

Hypoaminotransferasemia in patients undergoing long-term hemodialysis: clinical and biochemical appraisal

BACKGROUND & AIMS

It has been reported that patients with chronic renal failure have low serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels as a result of vitamin B6 deficiency. Chronic hepatitis C is common among patients undergoing hemodialysis, and low aminotransferase levels cause diagnostic problems. The aim of this study was to determine the cause of hypoaminotransferasemia.

METHODS

Serum levels of vitamin B6 and its coenzyme were reassessed in relation to AST and ALT levels in patients undergoing long-term hemodialysis using high-performance liquid chromatography.

RESULTS

The mean (+/- SD) serum AST and ALT levels in 304 patients negative for hepatitis B surface antigen and anti-hepatitis C virus were 9.2 +/- 2.4 and 7.4 +/- 1.7 IU/L, respectively. In 556 normal adults, they were 22.7 +/- 5.4 and 18.0 +/- 4.0 IU/L, respectively (P < 0.001). Mean serum vitamin B6 and pyridoxal-5'-phosphate levels in patients undergoing dialysis were not reduced compared with the control, although occasionally patients had low levels. The AST and ALT assay reagents in Japan do not contain added pyridoxal-5'-phosphate; addition of pyridoxal-5'-phosphate (0.1 mmol/L) to the reagent significantly increased measurements to similar extents in both groups.

CONCLUSIONS

Serum AST and ALT levels in patients undergoing dialysis are very low, but they are not a result of vitamin B6 deficiency. The upper normal limits of AST and ALT levels in patients undergoing dialysis should be reduced considerably, and these levels should be interpreted with caution in the diagnosis of liver disease.

Endoscopic ultrasonography diagnosis of pancreatic cancer

Endoscopic ultrasound (EUS) was developed for the detection of small pancreatic cancer because the complete demonstration of the pancreas by conventional ultrasonography (US) was sometimes prevented by intestinal gas and echoic reduction due to the deeper position of the pancreas head and tail. In this article, the diagnosis, staging, limitations, and hazards of EUS for diagnosing pancreatic cancer are described.

Tumors of the papilla and distal common bile duct. Diagnosis and staging by endoscopic ultrasonography

In this article, the capability of endoscopic ultrasound (EUS) in the diagnosis and staging of carcinoma of the papilla of Vater and distal common bile duct is evaluated. Topics discussed include instruments and techniques, EUS diagnosis, preoperative staging by EUS, and diagnostic strategies.

Studies on agents with vasodilator and beta-blocking activities. III. Synthesis and activity of optical isomers of TZC-1370

Optical isomers of TZC-1370 (1) were prepared from (R)- and (S)-1-(2-chlorophenoxy)-2,3-epoxypropane. When given intravenously to anesthetized rats, the (S)-isomer was about 40 times more potent in terms of beta-blocking activity than the (R)-isomer, while their hypotensive activities were equipotent with that of the racemic compound, TZC-1370.

Responses of plasma adrenocortical steroids to low dose ACTH in normal subjects

OBJECTIVE

The standard ACTH test in clinical use employs a pharmacological dose of ACTH which assesses the maximum secretory capacity of the adrenal cortex. We have investigated the responses of plasma adrenocortical steroids including cortisol, aldosterone and dehydroepiandrosterone (DHEA) to physiological doses of ACTH (ACTH 1-24, tetracosactide, Cortrosyn) and determined the minimal dose which induces a response equivalent to that induced by a pharmacological dose of ACTH.

DESIGN

Rapid ACTH tests at various physiological (0-1, 0.5, 1 and 5 micrograms) and standard pharmacological (250 micrograms) intravenous doses.

SUBJECTS

Seven healthy normal volunteers.

MEASUREMENTS

Plasma cortisol, aldosterone and DHEA were measured. Peak value and the increment from basal value were used as indices of responses.

RESULTS

Each steroid responded to physiological doses of ACTH in a dose dependent manner. The minimum dose inducing an equivalent response to 250 micrograms ACTH was 0.5 micrograms for peak and incremental values in cortisol and DHEA, while that for aldosterone was 0.1 microgram. The time to peak for each steroid was delayed as the dose increased. Plasma aldosterone and DHEA peaked significantly earlier than plasma cortisol in 1-5 micrograms and 0.5-5-micrograms ACTH tests, respectively.

CONCLUSIONS

These results suggest that the sensitivity of secretion to physiological doses of ACTH in descending order is aldosterone > DHEA = cortisol. When peak and incremental values are used, sufficient doses of ACTH are 0.1 microgram for plasma aldosterone and 0.5 microgram for plasma cortisol and DHEA in the rapid ACTH test.

Effects of wortmannin on glucose uptake and protein kinase C activity in rat adipocytes

Wortmannin is known to be an inhibitor of myosin light chain kinase and phosphatidylinositol 3-kinase (PI 3-kinase) (J. Biol. Chem. 268, 25846, 1993). We studied the effects of wortmannin on insulin- and 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced glucose uptake, purified PKC activity and in vitro 80 kDa protein phosphorylation to elucidate the relationship between insulin-induced PI 3-kinase and PKC activations. Pretreatment with 10(-12)-10(-6) M wortmannin for 60 min resulted in a dose-responsive reduction of 10 nM insulin-stimulated glucose uptake in rat adipocytes. Pretreatment with 10(-6) M wortmannin resulted in 80% and 20% decreases of glucose uptake stimulated by insulin and TPA, respectively. Partially purified rat brain PKC activity and 80 kDa protein in vitro phosphorylation of rat adipocyte cytosol by addition of Ca2+ and phospholipid were dose-dependently decreased by 10(-8)-10(-6) M wortmannin; 20% decrease of PKC activity and 50% decrease of 80 kDa protein phosphorylation by 10(-6) M wortmannin were observed. These results suggest that wortmannin has a potent inhibitory effect on PI 3-kinase and a weak inhibitory effect on PKC activity, and both effects cause a significant inhibition of insulin-stimulated glucose uptake in rat adipocytes.