Dengue: a newly emerging viral infection in Andaman and Nicobar Islands, India.

Prior to 2009 dengue fever had not been reported in the Andaman and Nicobar archipelago. In 2009, a few patients with dengue fever-like illness were reported, some of whom tested positive for dengue antibodies. In 2010, 516 suspected cases were reported, including some with dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS); 80 (15·5%) were positive for dengue antibodies. DENV RNA was detected in five patients and PCR-based typing showed that three of these belonged to serotype 1 and two to serotype 2. This was confirmed by sequence typing. Two clones of dengue virus, one belonging to serotype 1 and the other to serotype 2 appeared to be circulating in Andaman. Emergence of severe diseases such as DHF and DSS might be due to recent introduction of a more virulent strain or because of the enhancing effect of sub-neutralizing levels of antibodies developed due to prior infections. There is a need to revise the vector-borne disease surveillance system in the islands.

Diallyl disulfide suppresses the growth of human colon tumor cell xenografts in athymic nude mice.

The present studies examined the anti-proliferative effects of diallyl disulfide (DADS) on the growth of human colon tumor cell line, HCT-15, xenografts in 6-wk-old female NCr nu/nu mice with an initial body weight of 20-22 g. Intraperitoneal injection of 1 mg DADS thrice weekly reduced tumor volume by 69% (P < 0.05) without apparent ill consequences such as altered growth of the host. Providing this quantity of DADS intragastrically also inhibited growth of the HCT-15 tumor. At equivalent DADS dosages, intraperitoneal treatment was proportionately more effective (P < 0.05) in reducing tumor growth than gastric intubation. Tumor inhibition caused by DADS (0.5 mg thrice weekly) was similar to that occurring with 5-fluorouracil (5-FU) treatment (0.5 mg thrice weekly). Combining DADS and 5-FU was no more effective in inhibiting tumor growth than using either compound alone. However, concurrent DADS treatment significantly (P < 0.05) inhibited the depression in leukocyte counts and spleen weight and prevented the elevated plasma urea caused by 5-FU treatment. These data suggest that DADS, a constituent of garlic oil, reduces the toxicity of 5-FU and is an effective antitumorigenic agent against xenografts resulting from an established human colon tumor cell line.

Diallyl disulfide induces apoptosis of human colon tumor cells.

The present studies compared the effects of various oil-soluble compounds containing allyl and disulfide groups on the proliferation of cultured human colon tumor cells (HCT-15). Diallyl disulfide (DADS) was more effective in inhibiting the growth of HCT-15 cells than isomolar concentrations of S-allyl cysteine, dipropyl disulfide (DPDS), allyl chloride, allyl glycidyl ether and allyl alcohol. These studies clearly demonstrate the importance of both the diallyl and the disulfide groups in DADS. Treatment of HCT-15 cells with 100 microM DADS increased the intracellular calcium levels by 40%, while DPDS caused only a 12% increase in intracellular calcium. Exposure to 100 microM DADS or more, but not DPDS, caused the cells to undergo apoptosis as determined by morphological changes and DNA fragmentation. A positive correlation (r=0.944) was found between DADS-induced DNA fragmentation and its ability to increase intracellular free calcium levels. The widespread effectiveness of DADS was evident by its ability to inhibit the growth of human colon (HCT-15), skin (SK MEL-2) and lung (A549) tumor cell lines.

Diallyl disulfide inhibits the proliferation of human tumor cells in culture.

Diallyl disulfide (DADS), an oil-soluble organosulfur compound in processed garlic, was more effective in inhibiting the in vitro growth of human tumor cell lines: HCT-15 (colon), A549 (lung), and SK MEL-2 (skin) than isomolar quantities of the water-soluble compound S-allyl cysteine (SAC). Addition of DADS (100 microM) was cytostatic to all three cell lines. The importance of the allyl and the disulfide groups were revealed by the lack of a comparable depression in the growth of HCT-15 cells exposed to its saturated analogue, dipropyl disulfide (DPDS). Treatment with DADS also resulted in a dose-dependent increase in intracellular free calcium in cells. A dose-dependent decrease in the activity of calcium-dependent ATPase enzyme occurred in HCT-15 cells exposed to increasing quantities of DADS. A correlation (r = -0.975) was found between the intracellular free calcium levels and the Ca-ATPase activity in DADS-treated cells. These studies document that DADS, a constituent of garlic oil, is an effective inhibitor of the growth of human neoplastic cells. Alterations in calcium hemostasis are likely involved in the growth inhibition/cytotoxicity caused by DADS.

Impact of organosulfur compounds in garlic on canine mammary tumor cells in culture.

Six organosulfur compounds found in garlic were examined for their ability to alter the growth of canine mammary tumor cells (CMT-13) in culture. Water-soluble organosulfur compounds (S-allyl-cysteine, S-ethyl-cysteine and S-propyl-cysteine) did not significantly alter the growth of CMT-13 cells when added to cultures at 1.0 mM or less. However, oil-soluble organosulfur compounds (diallyl sulfide, diallyl disulfide and diallyl trisulfide) markedly inhibited growth. Increasing addition of diallyl disulfide (DADS) resulted in a progressive decrease in CMT-13 cell growth. Addition of glutathione before DADS markedly decreased the severity of the growth inhibition. Treatment with DL-buthionine-SR-sulfoxamine, a specific inhibitor of glutathione synthesis, accentuated the growth inhibition caused by DADS. These studies show that some organosulfur compounds found in garlic are effective inhibitors of the growth of the neoplastic CMT-13 cell. The inhibitory effects of these compounds are modified by intracellular glutathione.

The relevance and use of mouse embryo bioassays for quality control in an assisted reproductive technology program.

OBJECTIVE: To define both the limits of a mouse embryo bioassay for quality control in an assisted reproductive technology (ART) program and the areas where it can be effectively used. DESIGN: Embryos at the pronuclear and two-cell stage from three different strains of mice were used to assess the effectiveness of this assay for media quality control using five different media routinely used in ART. Pronuclear and two-cell embryos from CD-1 mice were used to test the ability of a mouse embryo bioassay to control for water quality, contaminants in the culture system, and fluctuations in the environmental conditions using a medium, culture system, and scoring technique that were optimized for this strain. RESULTS: The mouse embryo bioassay is not effective in differentiating media appropriate for supporting human embryo development since the development of mouse embryos in vitro is strain, stage, and media related. However, CD-1 embryos were shown to be sensitive to variations in water quality, pH, temperature, incubator conditions, and contaminants in the system when grown in a protein-free medium optimized for their development. Both total blastocyst number and the cell count in the blastocysts were affected. Pronuclear embryos were more sensitive to perturbations in the culture system than two-cell embryos. CONCLUSIONS: A mouse embryo bioassay can be effectively used as a means of quality control of water, chemicals, and contact materials and for technique standardization and training in an assisted reproduction program. All the conditions of the test should be defined, pronuclear embryos should be used, and the end point should be fully expanded blastocysts and/or cell numbers in these blastocysts where appropriate.

The use of a liquid-phase controlled rate freezing system for the successful cryopreservation of mouse pre-embryos.

OBJECTIVES: To investigate the ability of a liquid-phase, controlled-rate freezing machine to generate reproducible freezing gradients with a constant rate of change; temperature fluctuations and heat dissipation during seeding; to assess the viability of mouse pre-embryos exposed to the silicone liquid cooling phase and the rates of survival and viability of mouse pre-embryos cryopreserved using this system. DESIGN: Freezing gradients were generated from the bath or a sample and compared for reproducibility and slope. Temperature fluctuations and gradients around the freezing chamber and the temperature rises and dissipation during seeding were measured. The toxicity of the silicone polymer freezing-phase was tested with mouse pronuclear pre-embryos. Different developmental stages of mouse pre-embryos were frozen and thawed and survival recorded in vitro and in vivo. SETTING: Research Laboratories, Sinai Hospital of Baltimore, Baltimore, Maryland. MAIN OUTCOME MEASURES: The reproducibility of freezing gradients; temperature fluctuations during seeding; and the in vitro and in vivo viability of mouse pre-embryos exposed to the silicone polymer or frozen and thawed. RESULTS: The freezing gradients generated were constant and reproducible with a constant rate of change; no temperature differences were recorded around the freezing chamber; temperature changes at seeding are minimal and rapidly dispersed. The silicone polymer was nontoxic to mouse pre-embryos and mouse pre-embryos frozen with the system and subsequently thawed are viable both in vitro and in vivo. CONCLUSIONS: This liquid-phase cryopreservation system is an attractive option for assisted reproductive technologies laboratories because liquid nitrogen is not required for operation, it is reliable, there are small temperature fluctuations during seeding, and it can be kept constantly running.

alpha-fetoprotein and screening markers of congenital disease.

Alpha-fetoprotein (AFP) is produced in the gut and liver during fetal life and appears to act like albumin in the adult. Because AFP appears in the maternal circulation during pregnancy, interest has been focused on its measurement in maternal serum to predict fetal abnormality. In addition, AFP, as an embryonic product, is elevated in certain malignant states. This article provides a summary of current clinical knowledge of AFP and its applications.

Intestinal phospholipase A and triglyceride lipase: localization and effect of fasting.

We investigated the distribution of phospholipase A and triglyceride lipase in the rat small intestine and the effects of heparin and hormones on enzyme release. Phospholipase A activity was 10 times higher in the ileum than in the jejunum; triglyceride lipase activity was threefold higher in the jejunum than in the ileum. Activities of both enzymes were much greater in villus than in crypt cells. The specific activity of phospholipase A was highest in microsomes and least in cytosol. The crude nuclei and brush-border fraction contained 40.5% of total phospholipase A activity; mitochondria contained 33.8%; and microsomes, 17.4%. Phospholipase A activity increased significantly in the distal intestinal mucosa in fasted rats compared with controls. Heparin did not increase the release of phospholipase A by isolated intestinal cells or perfused intestinal vasculature. Thus, the small intestine probably does not contribute significantly to the phospholipase A activity of postheparin plasma. Hormones and cAMP, which inhibit the secretion of phospholipase A and triglyceride lipase from isolated hepatocytes, had no effect on the release of either enzyme from intestinal cells.

Lipid synthesis in isolated intestinal cells.

Since the small intestine contributes significantly to serum cholesterol and very low density lipoprotein levels, acute regulation of lipid synthesis was investigated in isolated rat intestinal cells incubated in Krebs-Ringer bicarbonate buffer with 5 mM glucose and [14c]acetate or 3H2O. Incorporation of [14c]acetate into cellular lipids was 6- to 8-fold greater in crypt than in villus cells. In both cell types the distribution of 14C among the various lipid classes was as follows: 52.5% in triglycerides, diglycerides, and monoglycerides; 22.3% in cholesterol; 8.3% in cholesteryl esters; 1.9% in fatty acids; and 15.0% in phospholidpids. In contrast, the medium lipids contained significantly higher amounts of tri-, di- and monoglycerides (61.1%) and lower amounts of cholesteryl esters (2.3%) and phospholipids (11.9%). After saponification, 2/3 of the recovered 3H2O was in fatty acids and 1/3 in cholesterol. Ethanol (10 mM) tripled 3H2O incorporation into cellular lipids but had no effect on [14c]acetate incorporation. Epinephrine and norepinephrine (10 micron), glucagon (10 micron), dibutyryl cyclic AMP (1MM), dexamethasone (1 mM and 1 micron), and cholera toxin (1 microgram/ml) did not affect [14c]acetate incorporation. We concluded that ehtanol stimulates intestinal lipid synthesis; however, in sharp contrast to their inhibition of lipid synthesis in hepatocytes and adipocytes, catecholamines, glucagon, and dibutyryl cyclic AMP do not inhibit lipid synthesis in intestinal cells.