Clostridium difficile colitis in patients after kidney and pancreas-kidney transplantation

Limited data exist about Clostridium difficile colitis (CDC) in solid organ transplant patients. Between 1/1/99 and 12/31/02, 600 kidney and 102 pancreas-kidney allograft recipients were transplanted. Thirty-nine (5.5%) of these patients had CDC on the basis of clinical and laboratory findings. Of these 39 patients, 35 have information available for review. CDC developed at a median of 30 days after transplantation, and the patients undergoing pancreas-kidney transplantation had a slightly higher incidence of CDC than recipients of kidney alone (7.8% vs. 4.5%, P>0.05). All but one patient presented with diarrhea. Twenty-four patients (64.9%) were diagnosed in the hospital, and CDC occurred during first hospitalization in 14 patients (40%). Treatment was with oral metronidazole (M) in 33 patients (94%) and M+oral vancomycin (M+V) in 2 patients. Eight patients had recurrent CDC, which occurred at a median of 30 days (range 15-314) after the first episode. Two patients (5.7%) developed fulminant CDC, presented with toxic megacolon, and underwent colectomy. One of them died; the other patient survived after colectomy. CDC should be considered as a diagnosis in transplant patients with history of diarrhea after antibiotic use, and should be treated aggressively before the infection becomes complicated.

Isolation of bovine viral diarrhea virus 1, a pestivirus from autopsied lamb specimen from Tamil Nadu, India

An epizootic of febrile illness among the Madras red breed of sheep had occurred in 1994 in Verrapuram, Chennai, India. The epizootic was suspected as Rift Valley fever (RVF)-like sickness based on clinical features. However, its etiological agent could neither be isolated nor implicated conclusively. During the post-epizootic period a male lamb died of similar clinical features and the spleen was immediately collected. Inoculation of spleen suspension in infant mouse brain yielded a virus that was serially passaged in infant mice and rhabdomyosarcoma (RD) cells. Electron microscopic observations revealed virus particles resembling flaviviruses. RT-PCR performed on extracted total RNA from infected cells and mouse brains with flavivirus-specific or RVF-specific primers gave negative results. However, an amplicon of 280 bp was obtained with pestivirus-specific primers from the 5'-UTR. Further, a nested PCR yielded a product of 157 bp. Nucleotide sequencing of the 157 bp product showed 100% homology to BVDV-1. Western blot analysis with a flavivirus envelope protein-specific MAb revealed three proteins of 33 K, 45 K and 55 K. Further studies suggested that the 33 K and 55 K proteins were glycosylated. This is the first report of isolation of BVDV-1 from a lamb in India.

SUBACUTE CUTANEOUS LUPUS ERYTHEMATOSUS WITH PSEUDO-PORPHYRIA AND VITILIGO

Sub acute Cutaneous Lupus Erythematosus (SCLE) is a distinct subset of LupusErythematosus. It can present as non scarring psoriasiform or annular polycycliclesions. About half the patients fulfil the criteria of the American RheumatismAssociation for systemic lupus erythematosus. In this report, we present the case of a45 years old male who came with psoriasiform depigmented plaques and papulo-vesicular lesions developed after taking some medication. Clinically diagnosed as subacute cutaneous lupus erythematosus with acral vitiligo. A histopathological studyand urine analysis however revealed presence of pseudo porphyria along with theSCLE. Although SCLE is not a rare disease, the association of it with pseudo porphyriaand vitiligo is of significance as the treatment for SCLE and pseudo porphyria isphoto protection and for the vitiligo it is photo chemotherapy.ABSTRACTKey Words: Sub acute cutaneous lupus erythematosus, pseudo porphyria,vitiligo, psoriasiform eruptions.

Metabolism of benzyl alcohol via catechol ortho-pathway in methylnaphthalene-degrading Pseudomonas putida CSV86

Pseudomonas putida CSV86 metabolizes 1- and 2-methylnaphthalene through distinct catabolic and detoxification pathways. In spite of the similarity in the steps involved in the methylnaphthalene detoxification and the toluene side-chain hydroxylation pathways, the strain failed to utilize toluene or xylenes. However, it could grow on benzyl alcohol, 2- and 4-hydroxybenzyl alcohol. Metabolic studies suggest that the benzyl alcohol metabolism proceeds via the benzaldehyde, benzoate, and catechol ortho-cleavage pathway, in contrast to the well established catechol meta-cleavage pathway. Carbon source-dependent enzyme activity studies suggest that the degradation of aromatic alcohol involves two regulons. Aromatic alcohol induces the upper regulon, which codes for aromatic alcohol- and aromatic aldehyde-dehydrogenase and converts alcohol into acid. The aromatic acid so generated induces the specific lower regulon and is metabolized via either the ortho- or the meta-cleavage pathway. CSV86 cells transform 1- and 2-methylnaphthalene to 1- and 2-hydroxymethyl naphthalene, which are further converted to the respective naphthoic acids due to the basal level expression and broad substrate specificity of the upper regulon enzymes.

Fibrous dysplasia complicated by aneurysmal bone cyst formation affecting multiple cervical vertebrae

Fibrous dysplasia is a well-known benign dysplastic process of bone. However, fibrous dysplasia is very uncommon in the spine. Further, to our knowledge, coexistence of fibrous dysplasia and aneurysmal bone cyst in the spine has not been reported. This manuscript presents a patient who had both processes involving the cervical spine.

Is digital image compression acceptable within diabetic retinopathy screening?

AIMS

The National Screening Committee (NSC), whilst recommending the use of digital mydriatic retinal photography for diabetic retinopathy screening, has not yet accepted the use of digitally compressed images for grading. By greatly reducing the file size, however, compression of images is invaluable for storage and for its rapid transmission across computer networks. We undertook a study to compare the different levels of JPEG compression with the original bit-mapped image to determine whether there was any loss of clinical detail following compression.

METHODS

Three hundred and thirty images were analysed in this study. These images had been captured from 66 eyes consecutively photographed in a diabetic retinopathy screening programme, using a Sony DXC-950 P 3CCD colour video camera mounted on a Canon CR6-45NMf fundus camera. Single 45 degrees macula-centred images were taken from each eye. The images were compressed using the JPEG algorithm within Adobe Photoshop (version 4.0) and then displayed with a Sony Trinitron colour monitor. Four different levels of compression were used, JPEG-1, JPEG-2, JPEG-3, JPEG-4, and an objective analysis was undertaken using 'lesion counts'. The compressed images were assessed separately and blindly and the results compared with their original BMP images.

RESULTS

Eight BMP images could not be evaluated (five right eye and three left eye). A total of 290 images were therefore used in the final evaluation. All the JPEG-1 images with file sizes between 16 and 24 kb were found to be 'pixelated', while the JPEG-4 images (66-107 kb) appeared similar to the original BMP (1.3 Mb) images. Both JPEG-2 and JPEG-3 images had significantly lower counted lesions than the BMP images.

CONCLUSIONS

From our findings we can conclude that only some degree of image compression (compression ratios of 1 : 20 to 1 : 12) with file sizes of 66-107 kb is permissible using JPEG format, whereas the images obtained after higher compression ratios may not be suitable for diabetic retinopathy screening.

Glucose-induced suppression of endogenous glucose production: dynamic response to differing glucose profiles

To determine whether, in the presence of constant insulin concentrations, a change in glucose concentrations results in a reciprocal change in endogenous glucose production (EGP), glucagon ( approximately 130 ng/l) and insulin ( approximately 65 pmol/l) were maintained at constant "basal" concentrations while glucose was clamped at approximately 5.3 mM (euglycemia), approximately 7.0 mM (sustained hyperglycemia; n = 10), or varied to create a "postprandial" profile (profile; n = 11). EGP fell slowly over the 6 h of the euglycemia study. In contrast, an increase in glucose to 7.13 +/- 0.3 mmol/l resulted in prompt and sustained suppression of EGP to 9.65 +/- 1.21 micromol x kg-1 x min-1. On the profile study day, glucose increased to a peak of 11.2 +/- 0.5 mmol/l, and EGP decreased to a nadir of 6.79 +/- 2.54 micromol x kg-1 x min-1 by 60 min. Thereafter, the fall in glucose was accompanied by a reciprocal rise in EGP to rates that did not differ from those observed on the euglycemic study day (11.31 +/- 2.45 vs. 12.11 +/- 3.21 micromol x kg-1 x min-1). Although the pattern of change of glucose differed markedly on the sustained hyperglycemia and profile study days, by design the area above basal did not. This resulted in equivalent suppression of EGP below basal (-1,952 +/- 204 vs. -1,922 +/- 246 mmol. kg-1. 6 h-1). These data demonstrate that, in the presence of a constant basal insulin concentration, changes in glucose within the physiological range rapidly and reciprocally regulate EGP.

Epidermodysolasia Verruciforms

Abstract

Restoration of silenced Peutz-Jeghers syndrome gene, LKB1, induces apoptosis in pancreatic carcinoma cells

Germ line mutations of the LKB1 tumor suppressor gene lead to Peutz-Jeghers syndrome (PJS) with a predisposition to cancer. Previous reports suggest that inactivation of this tumor-suppressor gene plays a role in the pathogenesis of gastrointestinal hamartomas as well as several cancers, including adenocarcinoma of the pancreas. Here, we have shown that LKB1 gene is silenced in the pancreatic cancer cell line AsPC-1, but can be recovered by treatment with the methylation inhibitor, 5-aza-2'-deoxycytidine (5aza2dC). Restoring the level of LKB1 through gene transfer initiated mitochondria-mediated apoptosis in AsPC-1 cells, as evidenced by the release of cytochrome c from the mitochondria. By confocal microscopy as well as biochemical fractionation, we demonstrate that LKB1 is present in the nuclear and mitochondrial compartments of pancreatic cancer cells. Our observations also indicate that although functional p53 is absent, the p53 kin, p73, is inducible by doxorubicin in AsPC-1 cells. This suggests that LKB1-induced apoptosis is p53 independent but might be p73-mediated in the pancreatic tumor cell line, AsPC-1.

The structure of the pineal complex in a common Indian teleost, Catla catla: evidence for pineal-induced inhibition of testicular function within an annual reproductive cycle

The structure of the pineal complex and the annual reproductive cycle in a major Indian carp, Catla catla, were investigated in the present study. Additionally, given the well-known inhibitory effects of the pineal on reproductive function in mammals, attempts were made to investigate whether or not the pineal exerts an inhibitory influence on reproductive function in this piscine species as well. Sexually adult animals were utilized in all experiments. The cytomorphology of the pineal complex and a number of parameters for testicular function--such as testicular cytology, serum testosterone levels, and testicular activities of two steroidogenic enzymes, 17beta-hydroxysteroid dehydrogenase (17beta-HSD) and delta5-3beta-hydroxysteroid dehydrogenase (delta5-3beta-HSD) were examined over a period of two years. Our studies showed that the pineal complex in this species consists of three separate but distinctly connected components: (a) an end vesicle (EV); (b) a long pineal stalk (PS); and (c) a dorsal sac (DS). Of these, the epithelial lining of the EV consists of cells that have rounded vesicular nuclei and long apical cytoplasmic processes that reach the lumen, features suggestive of photoreceptor cells. The cells of the PS have some similarity with those of the EV, while DS cells appear columnar and ciliated. With regard to gonadal activity, germ cell profiles revealed that this species has four distinct phases during the annual reproductive cycle: (a) preparatory (January-April); (b) pre-spawning (May-June); (c) spawning (July); and (d) post-spawning (August-December). During the spawning phase (July), seminiferous tubular diameter, percentage of late spermatids within seminiferous tubules, and serum testosterone levels showed the highest values compared to those obtained in most of the other phases of the reproductive cycle. Also in July, along with peak serum testosterone levels, the activities of 17beta-HSD and delta5-3beta-HSD were at their highest levels. In a correlation between the pineal cytology and testicular functional status, it was noted that both the nuclear diameter and the apical cytoplasmic projections of the EV photoreceptor cells showed a significant reduction, thus suggesting a reduced synthetic activity, during the month of July, the spawning phase of the reproductive cycle. In contrast, the same features of the EV cells during the other phases of the reproductive cycle showed an increased cellular and metabolic activity--a time when the gonads were less active and in a quiescent stage. These data suggest an inhibitory role of the pineal on gonadal function and thus provide additional credence to the concept that, as in higher mammals, there exists an inverse relationship between the pineal activity and gonadal function in teleost fishes as well.

Identification of a novel Bcl-xL phosphorylation site regulating the sensitivity of taxol- or 2-methoxyestradiol-induced apoptosis

Bcl-xL, a close homolog of Bcl2, is an important regulator of apoptosis and is overexpressed in human cancer. Phosphorylation of Bcl-xL can be induced by microtubule-damaging drugs such as taxol or 2-methoxyestradiol (2-ME). By site-directed mutagenesis studies, we have identified that serine 62 is the necessary site for taxol- or 2-ME-induced Bcl-xL phosphorylation in prostate cancer cells. Further studies with the inhibitor of Jun kinase (JNK) and phosphorylation null mutant of Bcl-xL reveal the augmentative role of JNK-mediated Bcl-xL phosphorylation in apoptosis of prostate cancer cells. In summary, our studies suggest that the phosphorylation of Bcl-xL by stress response kinase signaling might oppose the anti-apoptotic function of Bcl-xL to permit prostate cancer cells to die by apoptosis.

Chromosomal aberrations and sister chromatid exchanges in individuals exposed to arsenic through drinking water in West Bengal, India

Arsenic contamination in groundwater has become a worldwide problem. Currently an unprecedented number of people in West Bengal, India and Bangladesh are exposed to the ubiquitous toxicant via drinking water in exposure levels far exceeding the maximum recommended limit laid down by WHO. This arsenic epidemic has devastated nine districts of West Bengal encompassing an area of 38,865 km(2) leading to various clinical manifestations of chronic arsenicosis. We conducted a human bio-monitoring study using chromosomal aberrations (CA) and sister chromatid exchanges (SCE) as end points to explore the cytogenetic effects of chronic arsenic toxicity in the population of North 24 Parganas, one of the arsenic affected districts in West Bengal. Study participants included 59 individuals residing in this district where the mean level (+/-S.E.) of arsenic in drinking water (microg/l) was 211.70+/-15.28. As age matched controls with similar socio-economic status we selected 36 healthy, asymptomatic individuals residing in two unaffected districts--Midnapur and Howrah where the mean arsenic content of water (microg/l) was 6.35+/-0.45. Exposure was assessed by standardized questionnaires and by detecting the levels of arsenic in drinking water, nails, hair and urine samples. In the exposed group the mean arsenic concentrations in nails (microg/g), hair (microg/g) and urine (microg/l) samples were 9.04+/-0.78, 5.63+/-0.38 and 140.52+/-8.82, respectively, which were significantly high (P<0.01) compared to the corresponding control values of 0.44+/-0.03, 0.30+/-0.02 and 5.91+/-0.49, respectively. Elevated mean values (P<0.01) of the percentage of aberrant cells (8.08%) and SCEs per cell (7.26) were also observed in the exposed individuals in comparison to controls (1.96% and 5.95, respectively). The enhanced rates of CAs and SCEs among the residents of North 24 Parganas are indicative of the cytogenetic damage due to long term exposure to arsenic through consumption of contaminated water.

Mucinous Cystadenoma Ovary With a Component Of benign Teratoma-A rare Combination

Abstract

A RARE CASE OF PERFORATED MECKEL'S DIVERTICULUM PRESENTING WITH PERITONITIS IN A CHILD

ABSTRACT

Muscle changes in aging

This review summarizes the recent studies to understand the mechanisms of sarcopenia of aging. A decrease in mitochondrial and nuclear gene transcriptions in skeletal muscle is likely to be responsible for reduced synthesis rates of muscle mitochondrial protein, myosin heavy chain (MHC) and actin. A decrease in muscle mitochondrial protein synthesis could contribute to reduced mitochondrial function. A decrease in synthesis rate of MHC and actin, the key contractile proteins could be responsible for reduced muscle strength. The MHC synthesis rate seems to result from a selective decrease in transcription of MHC isoforms (MHCIIa and IIx) responsible for fast-twitch fibers. Resistance training increases MHC-I isoform mRNA levels with an overall increase in MHC synthesis rate. Aerobic training increases muscle oxidative enzymes equally in young and old but its impact on overall mitochondrial function remains to be clearly defined. Long-term studies are needed to determine the potential benefits and undesirable effects of replacements of various hormones that decline with aging. An individualized exercise prescription involving both aerobic and resistance training is definitely helpful to overcome many aging-related muscle dysfunctions.

Growth of respiratory syncytial virus in mink lung epithelial cells

Mink lung epithelial cells (Mv-1-Lu) were tested for their ability to support the growth and serial passage of respiratory syncytial virus (RSV) in vitro. Indian isolates of RSV induced distinctive cytopathic effect with typical rounding of cells followed by detachment with more than 50 per cent cells showing bright fluorescence using anti-RSV monoclonal antibodies in immunofluorescence test. Serial passage of RSV was possible in Mv-1-Lu cells without loss of sensitivity of the cells for virus growth. Titration of cell associated virus and virus released in the supernatant indicated that 60 per cent of the virus was released in the supernatant, and 40 per cent remained cell associated. Transmission electron microscopic studies of negatively stained RSV particles and ultra-thin sections of RSV infected Mv-1-Lu cells showed roughly spherical particles with club shaped projections, budding from the cytoplasmic membrane. These results indicate that Mv-1-Lu cell line is suitable for the growth and propagation of RSV.

Peripheral bone density in patients with rheumatoid arthritis and factors which influence it

INTRODUCTION: Patients with rheumatoid arthritis (RA) frequently possess a number of risk factors for osteoporosis. Additionally, oral steroids are often used to control active rheumatoid disease and may further potentiate bone loss. We wished to establish the degree of peripheral bone loss in RA and to assess the influence of oral steroids and other risk factors. METHODS: We measured bone mineral density (BMD) in the non-dominant forearm using a DTX 200 osteometer in 191 RA patients who were receiving oral prednisone in a dose of at least 5 mg daily for over 3 months. We compared the results with those of two other groups: 165 RA patients who had never received oral prednisone and 242 normal controls without RA or any history of steroid therapy. Forward stepwise multiple regression analysis was used to determine the effects of age, disease variables and steroids on BMD. RESULTS: Age (P<0.001), RA (P<0.02) and steroid therapy (P<0.05) were all associated with reduced BMD using multiple regression analysis. Duration of RA was also associated with reduced BMD (P<0.05), but activity of disease was not. By WHO criteria (BMD T score<-2.5 S.D.), 95 (50%) of the RA steroid-treated patients (RAS) had osteoporosis, while 48 (25%) of the RA patients not exposed to steroids (RAN) were osteoporotic. Among the normal controls (NC), 48 (20%) had osteoporosis. The mean (S.D.) BMD Z scores for the three groups were -0.8 (1.3) for RAS, -0.4 (1.3) for RAN and 0.0 (1.0) for NC (P<0.01 for all differences). The percentages of patients with a Z score of -1 or less were 51% for RAS, 29% for RAN and 14% for NC. These differences were also significant (P<0.01). Male sex was associated with reduced BMD when compared to female sex (Z<-1) in the RAS (57 vs. 49%; P<0.05) but not in the RAN (25 vs. 31%) groups. For men with RA, the mean (S.D.) BMD Z scores were -1.3 (1.3) for RAS compared to -0.5 (1.3) for RAN (P<0.005), while for women the differences were less marked at -0.7 (1.3) for RAS compared to -0.4 (1.3) for RAN (P<0.05). CONCLUSIONS: In general, patients with RA have a significantly reduced forearm BMD, which correlates with increasing disease duration. Exposure to oral steroids increases bone loss, notably in male patients. Patients with RA on oral steroids need BMD measurements with a view to prophylactic therapy in those with a low result. Previous fractures and a daily dose of 15 mg or more of prednisone are also important factors in determining when prophylaxis is indicated.

Hyponatremia and hypoglycemia in acute Sheehan's syndrome

We report the case of a 23-year-old Saudi Arabian woman who presented to the medical intensive care unit with severe hyponatremia and hypoglycemia following a Cesarean section delivery complicated by hemorrhage due to disseminated intravascular coagulopathy. She was treated successfully for adrenal insufficiency acutely, and was later discharged on hormone replacement therapy. To our knowledge, this is the first case report of acute Sheehan's syndrome presenting with both hyponatremia and suggestive hypoglycemia. Pituitary necrosis is an uncommon complication of peripartum hemorrhagic shock. Since the initial description by Sheehan in 1937, the incidence of the syndrome has gradually declined through improved management of hemodynamic complications leading to the infarction of the gland. There are many studies describing complications of late Sheehan's syndrome; however, relatively few contain descriptions of the acute phase. In addition, the diagnosis of this syndrome is often determined after resolution of the acute process with resultant lack of data regarding immediate endocrine and imaging abnormalities. In this report, we describe the complete endocrine and imaging assessment of a patient presenting in critical condition due to necrosis of the pituitary gland in the immediate postpartum period.

Signal-induced site specific phosphorylation targets Bcl2 to the proteasome pathway

The oncogene derived protein Bcl2 and its family members such as Bcl-xL or Mcl-1 can confer negative control in the pathway of cellular suicide machinery. The reversible phosphorylation of the components in the apoptotic-signaling pathway is likely to be an important regulatory mechanism to control the fate of a cell. Previous reports by others and us demonstrate that phosphorylation of anti-apoptotic proteins such as Bcl2, Bcl-xL or Mcl-1 can regulate their function depending on the apoptotic trigger or cell type. Also, evidence is now accumulating that the ubiquitin proteasome pathway can play an important role in apoptosis. In order to understand whether any cross-talk exists between proteasome and Bcl2 phosphorylation pathways, studies were undertaken employing cell permeable proteasome inhibitors. When proteasomes were inactivated, enhanced accumulation of slower mobility forms of Bcl2 was clearly evident. Due to substitution of the major phosphorylation sites Ser 70, 87 to Ala, no such effect was observed. It is known that in contrary to phospho Bcl2, native Bcl2 (non-phosphoform) is unable to associate with cis-trans peptidyl prolyl isomerase Pin1-a key factor to regulate the fate of phosphoforms of Bcl2 and apoptosis. Thus the enhanced resistance to cell death exhibited by phosphorylation defective mutant Bcl2 might be attributed to its inability to associate with Pin1.

2-Methoxyestradiol induces mitochondria dependent apoptotic signaling in pancreatic cancer cells

The antiproliferative action of 2-methoxyestradiol (2-ME), an endogenous estrogen metabolite is specific for cancer cells and is mediated by the induction of programmed cell death or apoptosis. But the identity of the downstream effectors of apoptotic signaling induced by 2-ME is not known. In the present study, we explored the effect of 2-ME on apoptosis in a panel of human pancreatic cancer cell lines. We have identified two categories of pancreatic cancer cell lines, which are either sensitive to 2-ME such as MIA PaCa-2, CFPAC-1, PANC-1, or non-sensitive to 2-ME such as Hs 766T. The results presented here indicated that the cell lines responsive to 2-ME could undergo apoptosis either by G2-M arrest (PANC-1) with Bcl-x(L) phosphorylation or by the accumulation of tetraploid cells in G1-S region (MIA PaCa-2) without Bcl-2/ Bcl-x(L) phosphorylation. Furthermore, 2-ME induced apoptosis in pancreatic cancer cells is mitochondria dependent as evident by the release of cytochrome c into the cytosol. 2-ME exposed cells exhibit Bid cleavage that is accompanied by the translocation of Bax into the mitochondria. Also 2-ME could induce phosphorylation of Bcl-x(L) in G2-M arrested cells, thus indicating the involvement of various anti- and pro-apoptotic regulators in the signaling cascade. The dissection of differential response of pancreatic cancer cell lines holds promise for future therapeutic intervention.

Increased K+ efflux and apoptosis induced by the potassium channel modulatory protein KChAP/PIAS3beta in prostate cancer cells

K(+) channel-associated protein/protein inhibitor of activated STAT (KChAP/PIAS3beta) is a potassium (K(+)) channel modulatory protein that boosts protein expression of a subset of K(+) channels and increases currents without affecting gating. Since increased K(+) efflux is an early event in apoptosis, we speculated that KChAP might induce apoptosis through its up-regulation of K(+) channel expression. KChAP belongs to the protein inhibitor of activated STAT family, members of which also interact with a variety of transcription factors including the proapoptotic protein, p53. Here we report that KChAP induces apoptosis in the prostate cancer cell line, LNCaP, which expresses both K(+) currents and wild-type p53. Infection with a recombinant adenovirus encoding KChAP (Ad/KChAP) increases K(+) efflux and reduces cell size as expected for an apoptotic volume decrease. The apoptosis inducer, staurosporine, increases endogenous KChAP levels, and LNCaP cells, 2 days after Ad/KChAP infection, show increased sensitivity to staurosporine. KChAP increases p53 levels and stimulates phosphorylation of p53 residue serine 15. Consistent with activation of p53 as a transcription factor, p21 levels are increased in infected cells. Wild-type p53 is not essential for induction of apoptosis by KChAP, however, since KChAP also induces apoptosis in DU145 cells, a prostate cancer cell line with mutant p53. Consistent with its proapoptotic properties, KChAP prevents growth of DU145 and LNCaP tumor xenografts in nude mice, indicating that infection with Ad/KChAP might represent a novel method of cancer treatment.

Proteasomal degradation of human peptidyl prolyl isomerase pin1-pointing phospho Bcl2 toward dephosphorylation

Microtubule inhibitor-induced Bcl2 phosphorylation is detrimental to its antiapoptotic function. Phosphorylation of Bcl2 predominantly occurs on two serine residues (70 and 87) in cells arrested at G2-M phase by microtubule disarraying agents. Phospho Bcl2 can associate with a cis-trans peptidyl prolyl isomerase, Pin1. Pin1 and its homologues are known to target the proline residue carboxyl terminal to the phosphorylated threonine or serine residue of mitotic phosphoproteins, such as Bcl2. However, it was not clear how an extranuclear protein could associate with nuclear Pin1. The confocal images of the immunofluorescence studies employing phospho Bcl2-specific antibody developed in the laboratory demonstrated the translocation of phospho Bcl2 inside the nucleus. Interestingly, proteasomal degradation of Pin1 facilitates dephosphorylation of phospho Bcl2 due to longer exposure of Taxol. Here we show for the first time that proteasomal degradation of Pin1 is the key factor to determine the fate of phosphoforms of Bcl2. When Pin1 is degraded by proteasomes, phospho Bcl2 is converted to its native form. Thus, transient conformational change of Bcl2 due to association with peptidyl prolyl isomerase can contribute to irreversible apoptotic signaling.

Identification of the primer binding domain in human immunodeficiency virus reverse transcriptase

We have labeled the primer binding domain of HIV1-RT with 5'-32P-labeled (dT)15 primer using ultraviolet light energy. The specificity of the primer cross-linking to HIV1-RT was demonstrated by competition experiments. Both synthetic and natural primers, e.g., p(dA)15, p(dC)15, and tRNA(Lys), inhibit p(dT)15 binding and cross-linking to the enzyme. The observed binding and cross-linking of the primer to the enzyme were further shown to be functionally significant by the observation that tRNA(Lys) inhibits the polymerase activity on poly(rA).(dT)15 template-primer as well as the cross-linking of p(dT)15 to the enzyme to a similar extent. At an enzyme to p(dT)15 ratio of 1:3, about 15% of the enzyme can be cross-linked to the primer. To identify the domain cross-linked to (dT)15, tryptic peptides were generated and purified by a combination of HPLC on a C-18 reverse-phase column and DEAE-Sephadex chromatography. A single peptide cross-linked to p(dT)15 was identified. This peptide corresponded to amino acid residues 288-307 in the primary sequence of HIV1-RT as judged by amino acid composition and sequence analyses. Further, Leu(289)-Thr(290) and Leu(295)-Thr(296) of HIV1-RT appear to be the probable sites of cross-linking to the primer p(dT)15.

Enhanced frequency of micronuclei in individuals exposed to arsenic through drinking water in West Bengal, India

In West Bengal, India arsenic in ground water has been found to be above the maximum permissible limit in seven districts covering an area of 37,493km2. In the present study, evaluation of the micronuclei (MN) formation in oral mucosa cells, urothelial cells and peripheral blood lymphocytes was carried out in the symptomatic individuals exposed to arsenic through drinking water. Forty five individuals with cutaneous signs of arsenicism from four affected districts (368.11 microg/l of As in drinking water) were considered as the exposed group and 21 healthy individuals with no symptoms of arsenic poisoning and residing in two unaffected districts (5.49 microg/l of As) were considered as controls. The exposed and control groups had similar age distribution and socioeconomic status. Standardised questionnaires were utilised and medical examination was conducted to ascertain exposure history, sociodemographic characteristics, diet, health, medication, addiction and chief symptoms in the study participants. Arsenic exposure was confirmed by measuring the arsenic content in the drinking water, nails, hair and urine samples from the volunteers. Arsenic contents in the urine, nail and hair in the exposed group were 24.45 microg/l, 12.58 and 6.97 microg/g, respectively which were significantly high in comparison to corresponding control group values of 4.88 microg/l, 0.51 and 0.34 microg/g, respectively. Exposed individuals showed a statistically significant increase in the frequency of MN in oral mucosa, urothelial cells and lymphocytes (5.15, 5.74 and 6.39/1000 cells, respectively) when compared with the controls (0.77, 0.56 and 0.53/1000 cells, respectively). Thus, the above results indicate that the symptomatic individuals exposed to arsenic through drinking water in this region have significant cytogenetic damage.

Glucose effectiveness: measurement in diabetic and nondiabetic humans

It is well established that under the conditions of daily living, insulin secretion and insulin action determine glucose tolerance in nondiabetic humans both in the post-absorptive and post-prandial states. However, in recent years, glucose effectiveness (i.e., the ability of glucose per se to stimulate its own uptake and to suppress its own release) has also been shown to influence glucose tolerance in both diabetic and nondiabetic individuals. In states of deficient insulin action, e.g., in individuals with type 2 diabetes, glucose effectiveness assumes a greater role in determining glucose tolerance both during fasting and post-prandial conditions. A mathematical model (Minimal Model) of glucose turnover has been applied to estimate glucose effectiveness in both diabetic and nondiabetic individuals. Several investigators have demonstrated reduced glucose effectiveness in people with type 2 diabetes mellitus. However, measurements of glucose effectiveness by the traditional single compartment minimal model approach have been fraught with errors when compared to model independent estimates, especially in the diabetic population. This has led investigators to modify the parameters of the model with the incorporation of glucose tracers and the use of two-compartment model of glucose kinetics. Although this has made the indices of glucose effectiveness more robust, proper validation experiments are necessary before widespread application of these methods.

Modeling of the refractive index and extinction coefficient of binary composite films

Southwell's analysis of optical multilayers within the limits of very thin films has been extended to include absorption in the multilayer for predicting the effective values of the refractive index n(e) and extinction coefficient k(e) of mixed-composition binary homogeneous films over a wide spectral region, including the high-absorption (k > 10(-2)) region. It has been found that n(e) in general is a complicated function of the optical parameters (n(1), k(1), n(2), k(2)) and volume fractions (f(1), f(2)) of the component materials in a homogeneous layer, and the expression for n(e) becomes the same as that predicted by the Drude model in the spectral region where the layers are transparent. Moreover, according to the present analysis, the volume fractions of the product of the refractive index and the extinction coefficient of the component materials of a binary composite film are additive and the sum equals the product of the effective refractive index and extinction coefficient of the composite film.

Microtubule-targeting drugs induce bcl-2 phosphorylation and association with Pin1

Bcl-2 is a critical suppressor of apoptosis that is overproduced in many types of cancer. Phosphorylation of the Bcl-2 protein is induced on serine residues in tumor cells arrested by microtubule-targeting drugs (paclitaxel, vincristine, nocodazole) and has been associated with inactivation of antiapoptotic function through an unknown mechanism. Comparison of a variety of pharmacological inhibitors of serine/threonine-specific protein kinases demonstrated that the cyclin-dependent kinase inhibitor, flavopiridol, selectively blocks Bcl-2 phosphorylation induced by antimicrotubule drugs. Bcl-2 could also be coimmunoprecipitated with the kinase Cdc2 in M-phase-arrested cells, suggesting that Cdc2 may be responsible for phosphorylation of Bcl-2 in cells treated with microtubule-targeting drugs. Examination of several serine-->alanine substitution mutants of Bcl-2 suggested that serine 70 and serine 87 represent major sites of Bcl-2 phosphorylation induced in response to microtubule-targeting drugs. Both these serines are within sequence contexts suitable for proline-directed kinases such as Cdc2. Phosphorylated Bcl-2 protein was discovered to associate in M-phase-arrested cells with Pin1, a mitotic peptidyl prolyl isomerase (PPIase) known to interact with substrates of Cdc2 during mitosis. In contrast, phosphorylation of Bcl-2 induced by microtubule-targeting drugs did not alter its ability to associate with Bcl-2 (homodimerization), Bax, BAG1, or other Bcl-2-binding proteins. Since the region in Bcl-2 containing serine 70 and serine 87 represents a proline-rich loop that has been associated with autorepression of its antiapoptotic activity, the discovery of Pin1 interactions with phosphorylated Bcl-2 raises the possibility that Pin1 alters the conformation of Bcl-2 and thereby modulates its function in cells arrested with antimicrotubule drugs.

STa-induced translocation of protein kinase C from cytosol to membrane in rat enterocytes

Escherichia coli heat stable enterotoxin (STa) binds to isolated rat intestinal epithelial cells and triggers a cascade reaction including increase of intracellular calcium levels ([Ca(2+)](i)) and membrane bound protein kinase C (PKC) activity. In response to STa, the cytosolic PKC activity falls from 110 to 35 nmol with increase of membrane bound PKC activity from 15 to 78 nmol. Furthermore, the increase of PKC activity induced by STa treatment was always preceded by an increase in [Ca(2+)](i). Cytosolic [Ca(2+)](i) was significantly higher (161 nM) in STa treated cells as compared to untreated cells (51.3 nM). In addition, immunoblot performed on extracts of STa treated rat enterocytes with a monoclonal antibody against PKC alpha showed a prominent band of PKC alpha. Translocation of PKC alpha could be blocked by dantrolene, a drug which inhibits the mobilisation of [Ca(2+)](i) from the intracellular store. Our results, therefore, provide evidence for the role of [Ca(2+)](i) in STa treated cells for the translocation of PKC alpha from cytosol to membrane.

Hepatitis C virus core protein modulates the interferon-induced transacting factors of Jak/Stat signaling pathway but does not affect the activation of downstream IRF-1 or 561 gene

Hepatitis C virus (HCV) has a propensity to cause chronic infection, with a low proportion of patients exhibiting a sustained response to interferon-alpha (IFNalpha) therapy. An earlier report suggested that HCV inhibits IFNalpha-induced signal transduction through the Jak/Stat pathway by preventing the formation of the transacting factor ISGF3 complex, although the effect on downstream pathway and the specific viral protein responsible for inhibition of IFNalpha-mediated signal transduction were not elucidated. HCV core protein displays a number of intriguing functional properties and has been implicated in virus-mediated pathogenesis. In this study, we have analyzed the effect of core protein upon IFNalpha- or IFNgamma-induced regulation of the Jak/Stat signaling pathway. HCV core protein expression exhibited a reduced Stat1 expression in IFN-treated mammalian cells. A gel retardation assay suggested a reduced level of formation of the transacting factors, GAF and ISGF3, in IFN-treated cells. Further studies from protein expression and RNase protection assay revealed that the reduced level of GAF or ISGF3 formation could be attributed to modulation of Stat1 protein expression, an important player for innate immunity in host defense mechanism. However, these modulatory effects did not interfere with the activation of the downstream effector genes, IRF-1 and 561, in IFN-treated cells. Stable transfectants of cells after introduction of a plasmid DNA encoding both the structural and the nonstructural proteins of HCV also exhibited a similar effect. Taken together, these results suggest that although expression of the core protein alone or with other HCV proteins modulate transacting factors of Jak/Stat signaling pathway, expression of the downstream effector genes IRF-1 and 561 remains unaffected upon IFN treatment and may contribute to host defense mechanism.

Involvement of protein kinase C-delta in DNA damage-induced apoptosis

We have previously shown that the protein kinase C (PKC) signal transduction pathway regulates cell death by the DNA damaging agent cis-diamminedichloroplatinum(II) (cDDP). In the present study we have investigated how PKC influences the sequence of events that are triggered by cDDP-induced DNA damage. cDDP caused activation of caspases-8, -9, -3, -7 and cleavage of PKCdelta. Rottlerin, a selective inhibitor of novel PKCdelta, blocked activation of caspases, proteolytic activation of PKCdelta and cell death induced by cDDP. In contrast, Gö 6976, an inhibitor of conventional PKCalpha and betaI, did not prevent cDDP-induced caspase activation and cDDP cytotoxicity. In HeLa cells, PKCdelta was distributed both in the cytosol and heavy membrane (HM) fraction containing mitochondria. While caspase-8 was primarily cytosolic, a small amount of caspases-9, -7 and -3 could be detected in the HM fraction. cDDP caused a time-dependent increase in Cytochrome c release from the mitochondria and processing of both cytosolic and membrane-associated caspases, as well as proteolytic cleavage of PKCdelta. Rottlerin attenuated late but not early release of Cytochrome c by cDDP. It, however, inhibited activation of caspases and proteolytic cleavage of PKCdelta in both cytosolic and HM fractions. The antiapoptotic effect of rottlerin was evident when it was added together with or following cDDP addition but not when added after cDDP was removed from the medium. Thus, the PKCdelta inhibitor acts at an early stage of the cDDP-induced cell death pathway that precedes caspase activation.

Genomic structures and population histories of linguistically distinct tribal groups of India

There are various conflicting hypotheses regarding the origins of the tribal groups of India, who belong to three major language groups--Austro-Asiatic, Dravidian and Tibeto-Burman. To test some of the major hypotheses we designed a genetic study in which we sampled tribal populations belonging to all the three language groups. We used a set of autosomal DNA markers, mtDNA restriction-site polymorphisms (RSPs) and mtDNA hypervariable segment-1 (HVS-1) sequence polymorphisms in this study. Using the unlinked autosomal markers we found that there is a fair correspondence between linguistic and genomic affinities among the Indian tribal groups. We reconstructed mtDNA RSP haplotypes and found that there is extensive haplotype sharing among all tribal populations. However, there is very little sharing of mtDNA HVS-1 sequences across populations, and none across language groups. Haplogroup M is ubiquitous, and the subcluster U2i of haplogroup U occurs in a high frequency. Our analyses of haplogroup and HVS-1 sequence data provides evidence in support of the hypothesis that the Austro-Asiatic speakers are the most ancient inhabitants of India. Our data also support the earlier finding that some of the western Eurasian haplogroups found in India may have been present in India prior to the entry of Aryan speakers. However, we do not find compelling evidence to support the theory that haplogroup M was brought into India on an "out of Africa" wave of migration through a southern exit route from Ethiopia. On the contrary, our data raise the possibility that this haplogroup arose in India and was later carried to East Africa from India.

Neuroblastoma cell lines--a versatile in vitro model in neurobiology

Neuroblastoma (NB) cell lines are transformed, neural crest derived cells, capable of unlimited proliferation in vitro. These cell lines retain the ability of differentiation into neuronal cell types on treatment with various agents. This ability of NB cells to proliferate as well as to differentiate makes it an excellent in vitro system for various studies. This review article focuses on the applications and potential uses of murine and human NB cell lines. NB cells are extensively used for testing neurotoxicity of putative drugs such as antimalarial or anticancer agents. NB cell lines have wide applications in virus research to understand various aspects of virus-host cell interactions at the molecular and cellular levels. They have been used to dissect the relationships between proliferation, differentiation and apoptosis. This feature has been useful in understanding the pediatric cancer--neuroblastoma and for development of newer therapies.

Weak and strong dynamic scaling in a one-dimensional driven coupled-field model: effects of kinematic waves

We study the coupled dynamics of the displacement fields in a one-dimensional coupled-field model for drifting crystals, first proposed by Lahiri and Ramaswamy [Phys. Rev. Lett. 79, 1150 (1997)]. We present some exact results for the steady state and the current in the lattice version of the model for a special subspace in the parameter space, within the region where the model displays kinematic waves. We use these results to construct the effective continuum equations corresponding to the lattice model. These equations decouple at the linear level in terms of the eigenmodes. We examine the long-time, large-distance properties of the correlation functions of the eigenmodes by using symmetry arguments, Monte Carlo simulations, and self-consistent mode-coupling methods. For most parameter values, the scaling exponents of the Kardar-Parisi-Zhang equation are obtained. However, for certain symmetry-determined values of the coupling constants the two eigenmodes, although nonlinearly coupled, are characterized by two distinct dynamic exponents. We discuss the possible application of the dynamic renormalization group in this context.

Renal transplantation in patients above 60 years of age in the modern era: a single center experience with a review of the literature

A retrospective study was conducted of 797 patients receiving renal transplants from January 1985 to March 1997. Patient and graft survival was compared for patients above and below the age of 60. Sixty-nine patients < or =60 years old received 73 kidneys. Race: 73% Caucasian, 26% Black, 1% Other. Sex: 68% M. Hypertension (19) and PCKD (15) were the most common diagnoses. Mean peak panel reactive antibody (PRA) was 37.7%. Donor age was 2 to 66 years. Mean Cold ischemic time was 28.1 hours. Follow-up was until death or until 8/30/97. Patients <60 years included: 62% Caucasian, 34% Black, 4% Other; 60% male, Mean PRA 39.3. Of the 69 study patients, 27 died: 19 with a functioning graft, 8 within one year of transplantation. Cardiovascular causes (19 patients, 72%) and infection (7 patients, 24%) were most common. Common causes of graft loss were death with a functioning graft (19) and chronic rejection (15); other causes were acute rejection and primary non-function. Univariate analysis of 18 risk factors showed CHF and past history of vascular surgery significantly (p < 0.05) affected time of return to dialysis. Multi variate analysis did not show these independent variables to be significant. Abnormal ejection fraction and presence of q waves on EKG significantly affected time to death (p < 0.05) on uni- and multi-variate analysis. After censoring patients that died with functioning grafts, difference in graft survival between > or =60 and <59 years was not significant (p > 0.2). In this study, 68% of older patients had allografts functioning at 1 year. The fact that older patients succumb over time from natural causes should not keep patients from transplantation. Immunosuppressive agents need to be limited to reduce the incidence of infection. Criteria need to be refined to define those who are at prohibitive risk, who may not be candidates for transplantation.

Type I diabetes mellitus does not alter initial splanchnic glucose extraction or hepatic UDP-glucose flux during enteral glucose administration

AIMS/HYPOTHESIS

Our aim was to determine whether an alteration in splanchnic glucose metabolism could contribute to postprandial hyperglycaemia in people with Type I (insulin-dependent) diabetes mellitus.

METHODS

Splanchnic glucose extraction, hepatic glycogen synthesis and endogenous glucose production were compared in 8 Type I diabetic patients and in 11 control subjects. Endogenous hormone secretion was inhibited with somatostatin while insulin (approximately 550 pmol/l) and glucagon (approximately 130 ng/l) concentrations were matched with exogenous hormone infusions. Glucose containing [3-3H] glucose was infused into the duodenum at a rate of 20 micromol.kg(-1).min(-1). Plasma glucose concentrations were maintained at about 8.5 mmol/l in both groups by means of a separate variable intravenous glucose infusion.

RESULTS

Initial splanchnic glucose uptake, calculated by subtracting the systemic rate of appearance of [3-3H] glucose from the rate of infusion of [3-3H] glucose into the duodenum, did not differ in the diabetic and non-diabetic patients (4.1 +/- 0.8 vs 3.0 +/- 1.0 micromol/kg/min). In addition, hepatic glycogen synthesis, measured using the acetaminophen glucuronide method did not differ (10.7 +/- 2.4 vs 10.1 +/- 2.7 micromol.kg(-1).min(-1)). On the other hand, suppression of endogenous glucose production, measured by an intravenous infusion of [6,6-2H2] glucose, was greater (p < 0.05) in the diabetic than in the non-diabetic subjects (1.7 +/- 1.6 vs 5.8 +/- 1.9 micromol.kg(-1).min(-1)).

CONCLUSION/INTERPRETATION

When glucose, insulin and glucagon concentrations are matched in individuals with relatively good chronic glycaemic control, Type I diabetes does not alter initial splanchnic glucose uptake of enterally delivered glucose or hepatic glycogen synthesis. Alterations in splanchnic glucose metabolism are not likely to contribute to postprandial hyperglycaemia in people with well controlled Type I diabetes.

Type 2 diabetes impairs splanchnic uptake of glucose but does not alter intestinal glucose absorption during enteral glucose feeding: additional evidence for a defect in hepatic glucokinase activity

We have previously reported that splanchnic glucose uptake, hepatic glycogen synthesis, and hepatic glucokinase activity are decreased in people with type 2 diabetes during intravenous glucose infusion. To determine whether these defects are also present during more physiological enteral glucose administration, we studied 11 diabetic and 14 nondiabetic volunteers using a combined organ catheterization-tracer infusion technique. Glucose was infused into the duodenum at a rate of 22 micromol. kg(-1). min(-1) while supplemental glucose was given intravenously to clamp glucose at approximately 10 mmol/l in both groups. Endogenous hormone secretion was inhibited with somatostatin, and insulin was infused to maintain plasma concentrations at approximately 300 pmol/l (i.e., twofold higher than our previous experiments). Total body glucose disappearance, splanchnic, and leg glucose extractions were markedly lower (P < 0.01) in the diabetic subjects than in the nondiabetic subjects. UDP-glucose flux, a measure of glycogen synthesis, was approximately 35% lower (P < 0.02) in the diabetic subjects than in the nondiabetic subjects. This was entirely accounted for by a decrease (P < 0.01) in the contribution of extracellular glucose because the contribution of the indirect pathway to hepatic glycogen synthesis was similar between groups. Neither endogenous and splanchnic glucose productions nor rates of appearance of the intraduodenally infused glucose in the portal vein differed between groups. In summary, both muscle and splanchnic glucose uptake are impaired in type 2 diabetes during enteral glucose administration. The defect in splanchnic glucose uptake appears to be due to decreased uptake of extracellular glucose, implying decreased glucokinase activity. Thus, abnormal hepatic and muscle (but not gut) glucose metabolism are likely to contribute to postprandial hyperglycemia in people with type 2 diabetes.

Systemic and regional free fatty acid metabolism in type 2 diabetes

To determine whether type 2 diabetes mellitus alters systemic and regional free fatty acid ([3H]palmitate) metabolism, 14 nondiabetic (ND) and 14 type 2 diabetic (D) subjects underwent hyperinsulinemic-hyperglycemic (approximately 9.3 mM) clamps. The subjects were matched for age, body mass index, percent body fat, and fat-free mass. D subjects had more (P < 0.05) visceral fat than ND. During somatostatin, replacement growth hormone, and glucagon infusions, insulin was infused to achieve moderate (approximately 75 pmol/l) and high (approximately 150 pmol/l) physiological insulin levels. D subjects had greater (P < 0.02) systemic and regional (splanchnic and leg) palmitate release than ND subjects during both insulin infusion intervals. The relative contributions of splanchnic, leg, and nonsplanchnic upper body regions to systemic palmitate release did not differ between groups, although the last contributed the most (approximately 75%) to systemic palmitate release. Visceral fat area correlated with systemic palmitate flux (r = 0.45, P < 0.03) during both insulin infusions. We conclude that type 2 diabetes is associated with a generalized impairment in insulin suppression of lipolysis compared with equally obese ND individuals.

Genetic toxicology of a paradoxical human carcinogen, arsenic: a review

Arsenic is widely distributed in nature in air, water and soil in the form of either metalloids or chemical compounds. It is used commercially, as pesticide, wood preservative, in the manufacture of glass, paper and semiconductors. Epidemiological and clinical studies indicate that arsenic is a paradoxical human carcinogen that does not easily induce cancer in animal models. It is one of the toxic compounds known in the environment. Intermittent incidents of arsenic contamination in ground water have been reported from several parts of the world. Arsenic containing drinking water has been associated with a variety of skin and internal organ cancers. The wide human exposure to this compound through drinking water throughout the world causes great concern for human health. In the present review, we have attempted to evaluate and update the mutagenic and genotoxic effects of arsenic and its compounds based on available literature.

Horizontal and vertical transmission of dengue virus type 2 in highly and lowly susceptible strains of Aedes aegypti mosquitoes

Isofemale lines of Aedes aegypti mosquitoes highly and lowly susceptible to dengue type 2 (DEN-2) virus (DEN(h) and DEN(l), respectively) were established by oral feeding and individual rearing. The susceptibility at F13 generation was found to be 61% and 25% for the DEN(h) and DEN(l) line, respectively. The virus-infected mosquito females were allowed to probe on bovine albumin phosphate saline pH 7.2 (BAPS) through membrane feeders. The presence of virus in the probed BAPS was determined either by ELISA or by intrathoracic (i.t.) inoculation of mosquitoes or by both methods. The rate of oral transmission of virus was found to be 2 times higher in the DEN(h) isofemale line than in the DEN(l) one. Similarly, vertical transmission rate of the virus was found to be 7 times higher in the DEN(h) line. When batches of eggs obtained from infected female mosquitoes were allowed to hatch after two months the vertical transmission rate of the virus was very high. It is possible that, at room temperature, the virus gets an opportunity to multiply and increase its copy number in the quiescent embryos. The progeny obtained from the infected mosquitoes was found to be capable of transmitting the virus horizontally when allowed to probe on BAPS through the membrane feeder. This is the first report demonstrating horizontal transmission of DEN-2 virus by mosquitoes infected through vertical transmission. The higher vertical transmission rate of the virus in the progeny obtained from the eggs dessicated for a longer time and the horizontal transmission of the virus from the progeny is of very high epidemiological significance.

Effect of glucagon-like peptide-1(7-36)-amide on initial splanchnic glucose uptake and insulin action in humans with type 1 diabetes

In vitro studies indicate that glucagon-like peptide-1(7-36)-amide (GLP-1) can enhance hepatic glucose uptake. To determine whether GLP-1 increases splanchnic glucose uptake in humans, we studied seven subjects with type 1 diabetes on two occasions. On both occasions, glucose was maintained at approximately 5.5 mmo/l during the night using a variable insulin infusion. On the morning of the study, a somatostatin, glucagon, and growth hormone infusion was started to maintain basal hormone levels. Glucose (containing [3H]glucose) was infused via an intraduodenal tube at a rate of 20 micromol.kg(-1).min(-1). Insulin concentrations were increased to approximately 500 pmol/l while glucose was clamped at approximately 8.8 mmol/l for the next 4 h by means of a variable intravenous glucose infusion labeled with [6,6-2H2]glucose. Surprisingly, the systemic appearance of intraduodenally infused glucose was higher (P = 0.01) during GLP-1 infusion than saline infusion, indicating a lower (P < 0.05) rate of initial splanchnic glucose uptake (1.4 +/- 1.5 vs. 4.8 +/- 0.8 micromol.kg(-1).min(-1)). On the other hand, flux through the hepatic uridine-diphosphate- glucose pool did not differ between study days (14.2 +/- 5.5 vs. 13.0 +/- 4.2 micromol.kg(-1).min(-1)), implying equivalent rates of glycogen synthesis. GLP-1 also impaired (P < 0.05) insulin-induced suppression of endogenous glucose production (6.9 +/- 2.9 vs. 1.3 +/- 1.4 micromol.kg(-1).min(-1)), but caused a time-dependent increase (P < 0.01) in glucose disappearance (93.7 +/- 10.0 vs. 69.3 +/- 6.3 micromol.kg(-1).min(-1); P < 0.01) that was evident only during the final hour of study. We conclude that in the presence of hyperglycemia, hyperinsulinemia, and enterally delivered glucose, GLP-1 increases total body but not splanchnic glucose uptake in humans with type 1 diabetes.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.