Phylogeny of Vibrio cholerae based on recA sequence

We sequenced a 705-bp fragment of the recA gene from 113 Vibrio cholerae strains and closely related species. One hundred eighty-seven nucleotides were phylogenetically informative, 55 were phylogenetically uninformative, and 463 were invariant. Not unexpectedly, Vibrio parahaemolyticus and Vibrio vulnificus strains formed out-groups; we also identified isolates which resembled V. cholerae biochemically but which did not cluster with V. cholerae. In many instances, V. cholerae serogroup designations did not correlate with phylogeny, as reflected by recA sequence divergence. This observation is consistent with the idea that there is horizontal transfer of O-antigen biosynthesis genes among V. cholerae strains.     

Vitamin K status of preterm infants with a prolonged prothrombin time

AIM: To investigate the vitamin K status of preterm infants who have a prolonged prothrombin time (PT) in the first month of life. METHODS: Measures of vitamin K status were assessed in 21 preterm infants who were found to have an abnormal PT, despite 0.2-0.5 mg vitamin K(1) prophylaxis at birth. RESULTS: All infants had normal or supraphysiological vitamin K(1) concentrations and undetectable or, in one infant, insignificant PIVKA-II, indicating adequate vitamin K status. CONCLUSION: In preterm infants born at <32 wk gestation who received > or = 0.2 mg vitamin K(1) after delivery, a prolonged PT in the first month of life is unlikely to be due to vitamin K deficiency.     

Fragmented population structure of plasmodium falciparum in a region of declining endemicity

BACKGROUND: The population genetic structure of Plasmodium falciparum differs between endemic regions, but the characteristics of a population recently fragmented by effective malaria control have been unknown. METHODS: Genotypic analysis of 10 microsatellite loci widely separated in the parasite genome was conducted on 288 P. falciparum isolates from 8 foci in Malaysian Borneo, a region in which malaria incidence has been progressively reduced. RESULTS: Within all P. falciparum foci, moderate levels of allelic diversity were found, but levels of multilocus linkage disequilibrium were extremely variable. The population with the highest proportion of mixed-clone infections also had the highest allelic diversity and nonsignificant linkage disequilibrium. In contrast, several populations showed evidence of clonal expansion, and one offshore island population had exceptionally high levels of linkage disequilibrium. Genetic differentiation between many populations was very high and strongly associated with the geographical distance between them. CONCLUSIONS: High levels of differentiation and contrasting population structure among P. falciparum populations in Malaysian Borneo indicate that they are genetically independent. This supports the feasibility of individually eradicating the remaining P. falciparum foci.     

Effect of Bauhinia racemosa stem bark on N-nitrosodiethylamine-induced hepatocarcinogenesis in rats

The aim of this study is to investigate the antioxidant defense system induced by the methanol extract of Bauhinia racemosa L.(MEBR) against N-nitrosodiethylamine (NDEA)-induced hepatocarcinogenesis in Wister albino rats. The effects of MEBR on surface visible macroscopic (Morphometry) liver lesions (neoplastic nodules) and the levels of serum enzymes, lipid peroxidation and antioxidants were evaluated in NDEA-induced hepatocarcinogenesis in rats. In rats treated, with NDEA, significantly elevated levels of serum enzymes (SGOT, SGPT and ALP), bilirubin and decreased levels of protein and uric acid were observed. Significantly elevated amount of malondialdehyde (MDA), the end product of lipidperoxidation, indicated higher levels of lipid peroxidation, which was accompanied by significantly decreased levels of antioxidants like vitamin C, vitamin E, reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). Administration of MEBR was able to suppress nodule development/hepatocellular lesion formation in rats. The extract treatment increases in antioxidant levels and dramatic decreases in lipid peroxidation levels. MEBR also produced a protective effect by decreasing the level of serum enzymes, bilirubin and increased the protein and uric acid levels. The results suggest that MEBR exert chemopreventive effects by suppressing nodule development and decreasing lipid peroxidation and enhancing the levels of antioxidants in NDEA carcinogenesis by reducing the formation of free radicals.     

Plasmodium knowlesi malaria in humans is widely distributed and potentially life threatening.

BACKGROUND: Until recently, Plasmodium knowlesi malaria in humans was misdiagnosed as Plasmodium malariae malaria. The objectives of the present study were to determine the geographic distribution of P. knowlesi malaria in the human population in Malaysia and to investigate 4 suspected fatal cases. METHODS: Sensitive and specific nested polymerase chain reaction was used to identify all Plasmodium species present in (1) blood samples obtained from 960 patients with malaria who were hospitalized in Sarawak, Malaysian Borneo, during 2001-2006; (2) 54 P. malariae archival blood films from 15 districts in Sabah, Malaysian Borneo (during 2003-2005), and 4 districts in Pahang, Peninsular Malaysia (during 2004-2005); and (3) 4 patients whose suspected cause of death was P. knowlesi malaria. For the 4 latter cases, available clinical and laboratory data were reviewed. RESULTS: P. knowlesi DNA was detected in 266 (27.7%) of 960 of the samples from Sarawak hospitals, 41 (83.7%) of 49 from Sabah, and all 5 from Pahang. Only P. knowlesi DNA was detected in archival blood films from the 4 patients who died. All were hyperparasitemic and developed marked hepatorenal dysfunction. CONCLUSIONS: Human infection with P. knowlesi, commonly misidentified as the more benign P. malariae, are widely distributed across Malaysian Borneo and extend to Peninsular Malaysia. Because P. knowlesi replicates every 24 h, rapid diagnosis and prompt effective treatment are essential. In the absence of a specific routine diagnostic test for P. knowlesi malaria, we recommend that patients who reside in or have traveled to Southeast Asia and who have received a "P. malariae" hyperparasitemia diagnosis by microscopy receive intensive management as appropriate for severe falciparum malaria.     

Altered expression, intracellular distribution and activity of lymphocyte calpain II in Duchenne muscular dystrophy

BACKGROUND: Calpain II is an calcium-dependent cysteine protease involved in essential regulatory or processing functions of the cell, mediated by physiological concentrations of Ca(2+). However, in an environment of abnormal intracellular calcium as in Duchenne muscular dystrophy (DMD), calpain is suggested to cause membrane alterations. METHODS: Twelve individuals with dystrophin gene deletion and an equal number of age and sex matched controls were chosen for the study. The expression pattern of calpain II (both at RNA and protein levels), its cellular location upon activation and its activity in lymphocytes were specifically assessed to know if our earlier report of increased calpain activity in DMD lymphocytes is a result of de novo synthesis or is due to basic defect in calcium handling. RESULTS: We found a significant increase in the expression, alteration in calpain II distribution and increased activity of this enzyme. CONCLUSION: Membrane abnormalities and altered signaling pathways observed in DMD lymphocytes may be due to increased association of calpain II onto membrane and cytosol.     

Clinicopathological features and survival outcomes of primary signet ring cell and mucinous adenocarcinoma of colon: retrospective analysis of VACCR database

Background

Signet ring cell carcinoma (SRCC) accounts for less than 1% of all colon cancers. We examined the clinicopathological features and prognosis of signet ring cell and mucinous adenocarcinoma (MCC) of colon.

Methods

A total of 206 patients diagnosed with SRCC from 1995 to 2009 were identified from the VA Central Cancer Registry (VACCR) database. Age, race, histology, grade, lymph node status, stage and type of treatment received data were collected.

Results

Out of 206 patients, 173 (84%) were white, 31 (15%) were black, and 2 patients were listed as unknown. Median age of diagnosis was 67 years as compared to 70 years for both mucinous cell (MCC) and non-mucinous adenocarcinoma (NMCC) of colon. Pathological T-stages were as follows: T1 =3%, T2 =5%, T3 =34%, T4 =26%, and unknown 32%. Of the total, 22.3% were located in cecum, 7.7% in appendix, 21.8% in ascending colon, 7.7% in hepatic flexure of colon, 11% in transverse colon, 2.9% in splenic flexure 4.4% in descending colon, and 15.5% in sigmoid colon. 46.5% were lymph node positive, 21% were lymph node negative, and 32.5% were unknown. SRCC were in general poorly differentiated tumors (57%), small proportion of patients included were well-differentiated tumors with focal signet ring cell pathology (10%) and in 33% grade was unknown. Among stage 3 patients, 34% patients received only surgery while 64% received surgery with adjuvant chemotherapy and 2% received chemotherapy alone. The stage specific 5-year survivals for SRCC, MCC and NMCC were--Stage I: 100%, 61%, and 41% respectively (P<0.0001); Stage II: 42%, 58% and 32% respectively (P<0.0001); Stage III: 19%, 41% and 47% respectively (P=0.0002); Stage IV: 1.5%, 7% and 31% respectively (P<0.0001). Median survival of SRCC compared to NMCC was 18.6 vs. 46 months (P<0.0001) and mucinous cell adenocarcinoma versus NMCC was 47.8 and 46 months (P=0.63) respectively.

Conclusions

SRCC of colon has poor survival rates compared to other histological subtypes. SRCC presents at an earlier age, has higher tumor grade and advanced stage at diagnosis when compared to mucinous and NMCC of colon. Due to rarity of this disease further prospective multi-institute studies are required for in-depth understanding of this disease.     

Cardiac fatty acid metabolism and ischemic memory imaging with nuclear medicine techniques

There has been a dramatic improvement in the clinical management of myocardial diseases with the advent of cardiac metabolic and molecular imaging. Although both myocardial perfusion and metabolic imaging provide insight of myocardium at risk for infarction or ischemia, it is known that metabolic derangements precede perfusion abnormalities, especially after reperfusion therapy. Deranged myocyte loses its flexibility of choosing the right substrate for energy production and it switches its substrate, especially between fatty acid (FA) and glucose depending on disease condition; for example, predominance of FA metabolism is noted in diabetic heart disease, whereas glucose metabolism is enhanced in pressure overload conditions such as left ventricular hypertrophy. We thus hypothesize that with better technological advancements and different substrates, the metabolic footprint of various heart diseases can be charted out in future to help in the optimization of patient management. This review attempts to discuss the importance of radionuclide-labeled FAs in cardiac metabolic and ischemic memory imaging.     

Cloning and Sequencing of the Genes Downstream of the wbf Gene Cluster of Vibrio cholerae Serogroup O139 and Analysis of the Junction Genes in Other Serogroups

The DNA sequence of the O-antigen biosynthesis cluster (wbf) of a recently emergent pathogen, Vibrio cholerae serogroup O139, has been determined. Here we report the sequence of the genes downstream of the O139 wbfX gene and analysis of the genes flanking the wbf gene cluster in other serogroups. The gene downstream of wbfX, designated rjg (right junction gene), is predicted to be not required for O-antigen biosynthesis but appears to be a hot spot for DNA rearrangements. Several variants of the rjg gene (three different insertions and a deletion) have been found in other serogroups. DNA dot blot analysis of 106 V. cholerae strains showed the presence of the left and right junction genes, gmhD and rjg, respectively, in all strains. Further, these genes mapped to a single I-CeuI fragment in all 21 strains analyzed by pulsed-field gel electrophoresis, indicating a close linkage. The insertion sequence element IS1358, found in both O1 and O139 wb* regions, is present in 61% of the strains tested; interestingly, where present, it is predominantly linked to the wb* region. These results indicated a cassette-like organization of the wb* region, with the conserved genes (gmhD and rjg) flanking the divergent, serogroup-specific wb* genes and IS1358. A similar organization of the wb* region in other serogroups raises the possibility of the emergence of new pathogens by homologous recombination via the junction genes.