Predictive value of endoscopic findings in the diagnosis of active intestinal amebiasis

Endoscopic diagnosis of amebic colitis can be difficult because its appearance may mimic other forms of colonic disease. The aim of this study was to identify predictive endoscopic findings for amebic colitis. Patients with suspected amebic colitis based on distinctive endoscopic findings such as aphthae or erosions, ulcers, exudates, or a bump, were included in the study. A total of 157 patients were selected, 50 of whom had amebic colitis. The sensitivity and specificity of endoscopic findings that were significantly associated with amebic colitis were: cecal lesions (80% and 54%), multiple number of lesions (96% and 29%), presence of aphthae or erosions (84% and 37%), and presence of exudate (88% and 74%). Multivariate analysis revealed that the best combination of findings to predict amebic colitis was the presence of cecal lesions, multiple lesions, and exudates, which corresponded to an area under the receiver operating characteristic curve of 0.89 (95% confidence interval 0.82-0.95).

Low serum levels of total and high-molecular-weight adiponectin predict the development of metabolic syndrome in Japanese-Americans

BACKGROUND

Adiponectin is thought to play a significant role in the development of both insulin resistance and metabolic syndrome. Yet, there is very few evidence about the association plasma adiponectin and metabolic syndrome in the prospective study. Adiponectin exists as multimers in serum, and high-molecular-weight (HMW) adiponectin is particularly considered to be the active form of the protein.

AIM

We investigated whether serum HMW adiponectin as well as total adiponectin is associated with the development of metabolic syndrome in a longitudinal study.

SUBJECTS AND METHODS

We enrolled 224 men and 312 women of Japanese- Americans without metabolic syndrome at baseline who were followed for an average of 3.2 yr. The association of plasma total and HMW adiponectin with a progression to metabolic syndrome was examined.

RESULTS

Subjects who developed metabolic syndrome had significantly lower plasma total and HMW adiponectin levels at baseline than those who did not develop metabolic syndrome. In a Cox proportional hazards model, lower total and HMW adiponectin levels were independent risk factors for the development of metabolic syndrome after adjusting for age, body mass index, classification of 75-g glucose tolerance test, and homeostasis model assessment (hazards ratio: total, 0.684, p=0.017, in men; 0.606, p=0.003, in women; HMW, 0.687, p=0.014, in men; 0.704, p=0.029, in women, respectively).

CONCLUSIONS

Low circulating levels of total and HMW adiponectin may be a possible predictor for the development of metabolic syndrome.

Role of anti-oncomirs miR-143 and -145 in human colorectal tumors

We examined the expression levels of microRNAs (miRNAs (miRs)) in colorectal tumors (63 cancer specimens and 65 adenoma specimens) and paired non-tumorous tissues. Decreased expression of miR-143 and -145 was frequently observed in the adenomas and cancers tested, compared with miR-34a downregulation and miR-21 upregulation. Expression profiles of miR-143 and -145 were not associated with any clinical features. As the downregulation of miR-143 and -145 was observed even in the early phase of adenoma formation, the decreased expression of both miRs would appear to contribute mainly to the initiation step of tumorigenesis, not to the progression stage, and not to clinical prognostic factors. For clinical application, we changed the sequences of the passenger strand in the miR-143 duplex and performed chemical modification at the 3'-overhang portion of miR-143, leading to greater activity and stability to nuclease. The cell growth inhibitory effect of the chemically modified synthetic miR-143 in vitro was greater than that of endogenous miR-143. The miR-143 showed a significant tumor-suppressive effect on xenografted tumors of DLD-1 human colorectal cancer cells. These findings suggest that miR-143 and -145 are important onco-related genes for the initiation step of colorectal tumor development and that the chemically modified synthetic miR-143 may be a hopeful candidate as an RNA medicine for the treatment of colorectal tumors.

Potent antidiabetic effects of rivoglitazone, a novel peroxisome proliferator-activated receptor-gamma agonist, in obese diabetic rodent models

The pharmacological effects of rivoglitazone, a novel thiazolidinedione-derivative peroxisome proliferator-activated receptor (PPAR)-gamma agonist, were characterized in vitro and in vivo. Rivoglitazone activated human PPARgamma more potently compared with rosiglitazone and pioglitazone and had little effect on PPARalpha and PPARdelta activity in luciferase reporter assays. In Zucker diabetic fatty (ZDF) rats, 14-day administration of rivoglitazone decreased the plasma glucose and triglyceride (TG) levels in a dose-dependent manner. The glucose-lowering effect of rivoglitazone was much more potent than those of pioglitazone (ED(50): 0.19 vs. 34 mg/kg) and rosiglitazone (ED(50): 0.20 vs. 28 mg/kg). In addition, rivoglitazone showed potent antidiabetic effects in diabetic db/db mice. In Zucker fatty rats, rivoglitazone at a dose of 0.1 mg/kg clearly ameliorated insulin resistance and lowered plasma TG levels by accelerating the clearance of plasma TG. Gene expression analysis in the liver and heart of ZDF rats treated with rivoglitazone for 14 days suggested that rivoglitazone may reduce hepatic glucose production and modulate the balance of the cardiac glucose/fatty acid metabolism in diabetic animals. In summary, we showed that rivoglitazone is a potent and selective PPARgamma agonist and has a potent glucose-lowering effect via improvement of the insulin resistance in diabetic animal models.

Manganese superoxide dismutase Ala16Val polymorphism is associated with the development of type 2 diabetes in Japanese-Americans

AIMS

Recent evidence indicates that oxidative stress may play an important role in the pathogenesis of insulin resistance and that gene polymorphism (Ala16Val) of manganese superoxide dismutase (MnSOD) may protect against reactive oxygen species (ROS) function. We aimed to test the hypothesis that the Ala16Val variant could be associated with the development of type 2 diabetes.

METHODS

We examined 523 nondiabetic Japanese-Americans who underwent a 75g oral glucose tolerance test (OGTT) and were followed for an average of 9.9 years. Cox proportional hazard analysis, stratified by category of OGTT, was used to determine whether the Ala16Val polymorphism was a risk factor in the development of type 2 diabetes.

RESULTS

During the follow-up period, 65 subjects developed type 2 diabetes. Compared with Ala allele carriers, subjects with a Val homozygote showed significantly higher risk for developing diabetes (stratified hazard ratio=2.05 [95% confidence interval 1.03-4.08]; P=0.041) after adjustment for age, gender, systolic blood pressure, total cholesterol, body mass index, and homeostasis model assessment.

CONCLUSIONS

We demonstrated that the MnSOD Ala16Val polymorphism might be associated with development of type 2 diabetes among Japanese-Americans. These results suggest that insufficient ROS scavenging might be associated with a susceptibility to glucose intolerance.

HMG-CoA reductase inhibitors prevent bone loss in patients with Type 2 diabetes mellitus

AIMS

It has been reported that 3-hydroxy-3-methylglutaryl co-enzyme A (HMG-CoA) reductase inhibitors increase bone mineral density (BMD) in vivo. We investigated the effect of HMG-CoA reductase inhibitors on BMD in patients with Type 2 diabetes mellitus.

PATIENTS AND METHODS

We selected 122 patients with Type 2 diabetes, who were not taking active vitamin D preparations. Their mean age was 67.3 +/- 9.2 years. They were divided into a control group (n=63) without HMG-CoA reductase inhibitor therapy and an HMG-CoA group (n=59) who were treated with these drugs. The BMD of the distal one-third of the radius was measured by dual-energy X-ray adsorptiometry at baseline and after 2 years.

RESULTS

There were no significant differences between the control and HMG-CoA groups at baseline with respect to age, gender, body mass index, duration of diabetes, haemoglobin A1c, fasting plasma glucose, adjusted calcium, serum phosphorus, alkaline phosphatase, albumin excretion rate and radial BMD. However, there was a significantly smaller annual decrease of the radial BMD in the HMG-CoA group. Multiple regression analysis with a forward elimination procedure revealed a positive correlation of the radial BMD Z-score with body mass index, while there was a negative correlation with alkaline phosphatase and albumin excretion rate. In addition, the annual rate of change of the radial BMD showed a positive correlation with HMG-CoA reductase inhibitor therapy.

CONCLUSIONS

These findings suggest that HMG-CoA reductase inhibitors may prevent bone loss in patients with Type 2 diabetes.

Mesenteric panniculitis of the colon with obstruction of the inferior mesenteric vein: report of a case

Mesenteric panniculitis is a rare disease characterized by nonspecific inflammation of the fat tissue of the mesentery. We present an extremely rare case of mesenteric panniculitis of the sigmoid colon, complicated by occlusion of the inferior mesenteric vein. A 75-year-old male presented with a one-month history of abdominal distention and abdominal mass without pain. Physical examination revealed a firm mass in the lower abdomen. Barium enema study demonstrated rugged mucosa and a serrated contour in the rectosigmoid colon. Computed tomography showed that the mass arose from the mesentery, which surrounded the mesenteric vessels. The density of the mass was slightly higher than that of fatty tissue. Based on these radiologic findings, the patient was diagnosed as having mesenteric panniculitis of the rectosigmoid colon. Colonoscopy showed narrowing with edematous mucosa in the rectosigmoid colon, whereas marked dilated vessels were noted in the proximal portion of the sigmoid colon. Angiography showed occlusion of the inferior mesenteric vein, with venous flow returning via a collateral vein. The patient was observed without medication because his condition was satisfactory. His symptoms subsequently disappeared during a period of several weeks. The mass in the lower abdomen gradually diminished in size, disappearing three months later. Computed tomography and barium enema showed improvement of the lesion. The favorable outcome of the present case was probably because of formation of a collateral vein. The present case suggests that aggressive therapy for mesenteric panniculitis should be avoided, because the outcome of this disorder is good, even when there is obstruction of vessels.

Highly potent nociceptin analog containing the Arg-Lys triple repeat

One of the structural characteristics of a neuropeptide nociceptin is the existence of Arg-Lys (RK) residues at positions 8-9 and 12-13; both RKs have been suggested to bind to the acidic amino acid cluster in the second extracellular loop of the seven transmembrane domain receptor ORL1. With a design strategy of attempting to obtain an analog that binds more strongly to the receptor's acidic cluster, we synthesized a series of nociceptin analogs in which the RK dipeptide unit was placed at positions 6-7, 10-11, or 14-15 adjacent to the parent RKs. Among these nociceptin analogs containing the RK triple repeat, [Arg-Lys(6-7)]- and [Arg-Lys(10-11)]nociceptins exhibited weak activities (6-9 and 60-90% of nociceptin, respectively) both in the receptor binding assay and in the [(35)S]GTPgammaS binding functional assay. In contrast, [Arg-Lys(14-15)]nociceptin was found to be very potent in both assays (3-fold in binding and 17-fold in GTPgammaS functional assay). [Arg-Lys(14-15)]nociceptin was the first peptide analog found to be stronger than the parent nociceptin, and structure-activity studies have suggested that the incorporated Arg-Lys(14-15) interacts with either the receptor acidic amino acid cluster or the receptor aromatic amino acid residues.

X-ray structure of azide-bound fully oxidized cytochrome c oxidase from bovine heart at 2.9 A resolution

Two azide ions were identified, one between the Fe and Cu atoms in the O(2)-reduction site and the other at the transmembrane surface of the enzyme, in the crystal structure of the azide-bound form of bovine heart cytochrome c oxidase at 2.9 A resolution. Two geometries, a mu-1,3 type geometry between the Fe and Cu atoms and a terminal geometry on the Fe atom, are equally possible for an azide ion in the O(2)--reduction site. The other azide molecule was hydrogen bonded to an amide group of an asparagine and a hydroxyl group of tyrosine in a mu-1,1 type geometry. The antisymmetric infrared bands arising from these azide ions, which show essentially identical intensity [Yoshikawa & Caughey (1992), J. Biol. Chem. 267, 9757-9766], strongly suggest terminal binding of the azide to Fe. The electron density of all three imidazole ligands to Cu(B) was clearly seen in the electron-density map of the azide-bound form of bovine heart enzyme, in contrast to the crystal structure of the azide-bound form of the bacterial enzyme [Iwata et al. (1995), Nature (London), 376, 660-669], which lacks one of the three imidazole ligands to Cu(B).

FHIT alterations in cancerous and non-cancerous cervical epithelium

We have reported a significant frequency of an alteration of the fragile histidine triad (fhit) gene in squamous-cell carcinoma of the uterine cervix (series 1). To further define the role of fhit alteration in the development of cervical carcinoma, we surveyed 36 normal cervical epithelium, 22 cervical intra-epithelial neoplasias (CINs) and 20 additional cases of invasive cervical carcinomas (series 2). fhit transcripts were analyzed using reverse-transcription-polymerase-chain-reaction amplification and sequencing. Loss of expression of fhit was observed in 14 of 48 (29%) invasive carcinomas (8/28, series 1; 6/20, series 2) but not in any normal squamous epithelia or CINs analyzed. Abnormal fhit transcripts, including deletions and/or insertions, were observed in 12 of 48 (25%) invasive carcinomas (9/28, series 1; 3/20, series 2), 6 of 22 (27%) CINs, and 10 of 40 (25%) normal squamous epithelia (0/4, series 1; 10/36, series 2). Point mutation was detected in 9 of 48 (19%) cervical carcinomas (8/28, series 1; 1/20, series 2). Inactivation in both alleles was observed in 18 of 48 cervical carcinomas (38%), but not in any of 22 CINs or 40 normal squamous epithelia. Loss or impaired expression of the fhit-gene product was detected in 13 of 30 (43%) cervical carcinomas by immunohistochemistry, whereas all 6 normal cervical epithelia, or 22 CINs, expressed fhit protein. There was a strong association of impaired fhit protein expression with the disruption of normal fhit transcript in cervical carcinoma. No apparent correlation was observed between fhit inactivation and HPV infection. Our results suggest that fhit-gene inactivation occurs, not as an initiating event, but rather as a later event in cervical carcinogenesis, when the cervical tumor has acquired an invasive character.

New cembranes from the soft coral sarcophyton species

Three new cembranes, including one with a 13-membered carbocyclic ring, have been isolated from the soft coral Sarcophyton sp.

Alteration of p16 and p15 genes in human uterine tumours

The roles of the p16 and p15 inhibitor of cyclin-dependent kinase tumour suppressor genes were examined in human uterine cervical and endometrial cancers. p16 mRNA, examined by reverse transcription polymerase chain reaction (RT-PCR), was significantly reduced in five of 19 (26%) cervical and four of 25 (16%) endometrial tumours. Reduced expression of p16 protein, detected by immunohistochemistry, occurred even more frequently, in nine of 33 (27%) cervical and seven of 37 (19%) endometrial tumours. Hypermethylation of a site within the 5'-CpG island of the p16 gene was detected in only one of 32 (3%) cervical tumours and none of 26 endometrial tumours. Homozygous p16 gene deletion, evaluated by differential PCR analysis, was found in four of 40 (10%) cervical tumours and one of 38 (3%) endometrial tumours. Homozygous deletion of p15 was found in three of 40 (8%) cervical tumours and one of 38 (3%) endometrial tumours. PCR-SSCP (single-strand conformation polymorphism) analysis detected point mutations in the p16 gene in six (8%) of 78 uterine tumours (four of 40 (10%) cervical tumours and two of 38 (5%) endometrial tumours). Three were mis-sense mutations, one in codon 74 (CTG-->ATG) and one in codon 129 (ACC-->ATC), both in cervical carcinomas, and the other was in codon 127 (GGG-->GAG) in an endometrial carcinoma. There was one non-sense mutation, in codon 50 (CGA-->TGA), in an endometrial carcinoma. The remaining two were silent somatic cell mutations, both in cervical carcinomas, resulting in no amino acid change. These observations suggest that inactivation of the p16 gene, either by homologous deletion, mutation or loss of expression, occurs in a subset of uterine tumours.

Structure analysis of bovine heart cytochrome c oxidase at 2.8 A resolution

The crystal structure of bovine heart cytochrome c oxidase has been determined at 2.8 A resolution by the multiple isomorphous replacement (MIR) method with three heavy-atom derivatives. An asymmetric unit of the crystal has a molecular weight of 422 kDa. Eight heavy atoms as main sites of a CH3HgCl derivative were clearly located by solving the difference Patterson function. The electron density obtained by the MIR method was refined by density modification, consisting of solvent flattening, histogram matching and non-crystallographic symmetry averaging. The enzyme exhibits a dimeric structure in the crystal. Out of 3606 amino-acid residues in 26 subunits in the dimer, 3560 residues were located in the electron-density map. The structure was refined by X-PLOR. The final R factor and the free R factor were 0.199 and 0.252 at 2.8 A resolution, respectively. One monomer in the dimeric structure with a stronger packing interaction has a lower averaged temperature factor than the other, by 16 A2. The region +/-12 A from the centre of the transmembrane part is almost 100% alpha-helix, despite the glycine residue content being as high as 7.1% in the transmembrane region. The residues around haem a of animals have evolved away from those of bacteria in contrast with the residues of the haem a3. The hierarchy of the structural organization of the enzyme complex has been proposed on the basis of intersubunit interactions.