Biotyping of Acinetobacter species isolated from clinical samples

We used the biotyping scheme using carbohydrate substrate utilization test with 14 carbon sources to speciate Acinetobacter isolates from blood and cerebrospinal fluid cultures of patients admitted to the postoperative neurosurgery ICU during January to November 1996. Sixty one patients culture positive for Acinetobacter sp. from blood or cerebrospinal fluid were followed up prospectively. Among these patients, 40 patients had clinically diagnosed infections like bacteriemia or meningitis while in 21 patients the isolation was regarded as contaminants. A. baumanniii was the most common isolate associated with clinical infections while A. lwoffii was more likely to be an environmental contaminant.

Structural anthropometric measurements for wheelchair mobile adults

Structural anthropometric measurements for males and females were determined for the wheelchair mobile adults. A photogrammetry methodology was used to obtain the measurements. The various subject demographics including age, level or type of dysfunction as well as the specified anthropometric dimensions of the wheelchair mobile subjects were identified. The data would be useful for the design of industrial workstations for wheelchair mobile adults. Present workstation design principles based on seated able-bodied anthropometric measurements would not be suitable for this population.

Phenotypic reversal of the btn1 defects in yeast by chloroquine: a yeast model for Batten disease

BTN1 of Saccharomyces cerevisiae encodes an ortholog of CLN3, the human Batten disease gene. We have reported previously that deletion of BTN1, btn1-Delta, resulted in a pH-dependent resistance to D-(-)-threo-2-amino-1-[p-nitrophenyl]-1,3-propanediol (ANP). This phenotype was caused by btn1-Delta strains having an elevated ability to acidify growth medium through an elevated activity of the plasma membrane H(+)-ATPase, resulting from a decreased vacuolar pH during early growth. We have determined that growing btn1-Delta strains in the presence of chloroquine reverses the resistance to ANP, decreases the rate of medium acidification, decreases the activity of plasma membrane H(+)-ATPase, and elevates vacuolar pH. However, an additional effect of this phenotypic reversal is that activity of plasma membrane H(+)-ATPase is decreased further and vacuolar pH is increased further as btn1-Delta strains continue to grow. This phenotypic reversal of btn1-Delta can be considered for developing a therapy for Batten disease.

Axonal transport of ribonucleoprotein particles (vaults)

RNA was previously shown to be transported into both dendritic and axonal compartments of nerve cells, presumably involving a ribonucleoprotein particle. In order to reveal potential mechanisms of transport we investigated the axonal transport of the major vault protein of the electric ray Torpedo marmorata. This protein is the major protein component of a ribonucleoprotein particle (vault) carrying a non-translatable RNA and has a wide distribution in the animal kingdom. It is highly enriched in the cholinergic electromotor neurons and similar in size to synaptic vesicles. The axonal transport of vaults was investigated by immunofluorescence, using the anti-vault protein antibody as marker, and cytofluorimetric scanning, and was compared to that of the synaptic vesicle membrane protein SV2 and of the beta-subunit of the F1-ATPase as a marker for mitochondria. Following a crush significant axonal accumulation of SV2 proximal to the crush could first be observed after 1 h, that of mitochondria after 3 h and that of vaults after 6 h, although weekly fluorescent traces of accumulations of vault protein were observed in the confocal microscope as early as 3 h. Within the time-period investigated (up to 72 h) the accumulation of all markers increased continuously. Retrograde accumulations also occurred, and the immunofluorescence for the retrograde component, indicating recycling, was weaker than that for the anterograde component, suggesting that more than half of the vaults are degraded within the nerve terminal. High resolution immunofluorescence revealed a granular structure-in accordance with the biochemical characteristics of vaults. Of interest was the observation that the increase of vault immunoreactivity proximal to the crush accelerated with time after crushing, while that of SV2-containing particles appeared to decelerate, indicating that the crush procedure with time may have induced perikaryal alterations in the production and subsequent export to the axon of synaptic vesicles and vault protein. Our data show that ribonucleoprotein-immunoreactive particles can be actively transported within axons in situ from the soma to the nerve terminal and back. The results suggest that the transport of vaults is driven by fast axonal transport motors like the SV2-containing vesicles and mitochondria. Vaults exhibit an anterograde and a retrograde transport component, similar to that observed for the vesicular organelles carrying SV2 and for mitochondria. Although the function of vaults is still unknown studies of the axonal transport of this organelle may reveal insights into the mechanisms of cellular transport of ribonucleoprotein particles in general.

A brief on Ayurvedic manuscripts preserved at Utkal University, Bhubaneswar

Amongst different institutions, "Parija Library" of Utkal University, Bhubaneswar has about 101 palm-leaf manuscripts (mss.) on Ayurveda to its credit. Most of these mss. have not been reported earlier. Herewith a brief description of these mss. has been made with the intention of bringing it out for the Ayurvedic fraternity and to enrich the literary stock of Ayurveda.

Action of BTN1, the yeast orthologue of the gene mutated in Batten disease

Neuronal ceroid-lipofuscinoses (NCL) are autosomal recessive disorders that form the most common group of progressive neurodegenerative diseases in children, with an incidence as high as 1 in 12,500 live births, and with approximately 440,000 carriers in the United States. Disease progression is characterized by a decline in mental abilities, increased severity of untreatable seizures, blindness, loss of motor skills and premature death. The CLN3 gene, which is responsible for Batten disease, has been positionally cloned. The yeast gene, denoted BTN1, encodes a non-essential protein that is 39% identical and 59% similar to human CLN3. Strains lacking Btn1p, btn1-delta, are resistant to D-(-)-threo-2-amino-1-[p-nitrophenyl]-1,3-propanediol (ANP) in a pH-dependent manner. This phenotype was complemented by expression of human CLN3, demonstrating that yeast Btn1p and human CLN3 share the same function. Here, we report that btn1-delta yeast strains have an abnormally acidic vacuolar pH in the early phases of growth. Furthermore, DNA microarray analysis of BTN1 and btn1-delta strains revealed differential expression of two genes, with at least one, HSP30, involved in pH control. Because Btn1p is located in the vacuole, we suggest that Batten disease is caused by a defect in vacuolar (lysosomal) pH control. Our findings draw parallels between fundamental biological processes in yeast and previously observed characteristics of neurodegeneration in humans.

Influence of iron on growth and extracellular products of Acinetobacter baumannii

Iron is an important nutrient required by bacteria for optimal growth. Acquisition of iron from the host where iron is restricted is an important mediator of bacterial pathogenesis. In iron deplete chemically defined medium (CDM-Fe) growth of Acinetobacter baumannii was restricted as compared to iron replete medium (CDM + Fe). Bacteria developed four high molecular weight outer membrane proteins (OMPs) of 88, 84, 80 and 77 kDa in CDM-Fe medium which were absent in CDM + Fe medium, and are known iron regulated outer membrane proteins (IROMPs). A. baumannii secreted siderophores extracellularly into the medium which act as iron chelators which had been demonstrated in the supernatants of CDM-Fe media. The siderophore was of catechol type. This shows that A. baumannii under iron restricted conditions express IROMPs along with production of catechol type siderophore in order to acquire iron from the external milieu.

In vitro activities of ampicillin-sulbactam and amoxicillin-clavulanic acid against Acinetobacter baumannii

In vitro susceptibility patterns of newer beta-lactamase-inhibiting antibiotics ampicillin-sulbactam (A/S) and amoxicillin-clavulanic acid (A/C) for 100 consecutive isolates of Acinetobacter baumannii obtained from various clinical samples were studied. The A/C MIC for 86% of the strains was more than 16/8 microgram/ml, whereas there was an A/S MIC of more than 16/8 microgram/ml for only 38% of the strains. This showed that A/S has significantly superior in vitro activity compared to A/C against A. baumannii, although, theoretically, both should have similar activities. The therapeutic superiority of A/S over A/C needs to be studied, or else the breakpoints for these agents in in vitro tests need to be redefined.

The first conversion of camptothecin to (S)-mappicine by an efficient chemoenzymatic method

Camptothecin has been converted for the first time to (S)-mappicine via mappicine ketone, which is the sole product of the microwave irradiation of camptothecin. Baker's yeast reduction of mappicine ketone yielded (S)-mappicine in high optical purity.

Coronary artery bypass grafting without cardiopulmonary bypass

Coronary artery bypass surgery on a beating heart is now an accepted modality to treat selected patients of ischaemic heart disease. From June '92 through Sep '97, 162 patients underwent this procedure. There was no mortality and none of the patients had any respiratory or neurological morbidity, though 24% of the patients form a high risk group for conventional coronary bypass surgery. It is definitely cost effective in comparison to any other modalities for treatment of ischaemic heart disease. We conclude that continous use of this technique is justified and all cardiac surgeons should have exposure to this procedure.

Difluoromethylornithine antagonizes taxol cytotoxicity in MCF-7 human breast cancer cells

Taxol is a naturally occurring anticancer agent. We studied the combined effects of taxol with 0.1 mM of the ornithine decarboxylase inhibitor alpha-difluoromethylornithine (DFMO) in the MCF-7 human breast adenocarcinoma cell line. The effects of taxol on MCF-7 cells were evident at 0.05-1 microM and the half-maximum inhibition was calculated to be 0.05 microM. Although the cells in the control group continued to proliferate during an 8-day growth period, cells in the taxol-treated group showed approximately 78% inhibition on day 6 and approximately 92% inhibition on day 8. The combined effects of different concentrations of taxol with 0.1 mM DFMO for 48 h showed that DFMO reversed the cytotoxicity of taxol. The combined effects of 0.5 microM taxol and 0.1 mM DFMO over an 8-day period resulted in the reversal of taxol cytotoxicity by 74% on the sixth day of culture. Pretreatment and posttreatment with 0.1 mM DFMO protected the MCF-7 human breast adenocarcinoma cells from the cytotoxic effect of taxol. Polyamine levels were inhibited in cells treated with DFMO for 24 h. In a separate experiment, we verified that the addition of exogenous putrescine along with taxol and DFMO to cultures for 48 h restored the cytotoxic effects of taxol. Following exposure to 0.5 microM taxol, over 59% of MCF-7 cells were in G2/M phase. DFMO (0.1 mM) showed only a slight increase in the G1 phase of the cell cycle. However, in cells treated with taxol and DFMO, there was no change in the percent of cells in the G2/M phase compared to taxol-treated cells. Therefore, depletion of cellular polyamines may not interfere with cell cycle changes induced by taxol. Treatment of MCF-7 cells with 0.5 microM taxol resulted in the fragmentation of genomic DNA, indicating apoptosis, whereas the combined effects of taxol with DFMO inhibited DNA fragmentation.

Role of substrates and products of PI 3-kinase in regulating activation of Rac-related guanosine triphosphatases by Vav

Mitogen stimulation of cytoskeletal changes and c-jun amino-terminal kinases is mediated by Rac small guanine nucleotide-binding proteins. Vav, a guanosine diphosphate (GDP)-guanosine triphosphate (GTP) exchange factor for Rac that stimulates the exchange of bound GDP for GTP, bound to and was directly controlled by substrates and products of phosphoinositide (PI) 3-kinase. The PI 3-kinase substrate phosphatidylinositol-4,5-bisphosphate inhibited activation of Vav by the tyrosine kinase Lck, whereas the product phosphatidylinositol-3,4,5-trisphosphate enhanced phosphorylation and activation of Vav by Lck. Control of Vav in response to mitogens by the products of PI 3-kinase suggests a mechanism for Ras-dependent activation of Rac.

Negative correlation between male allocation and rate of self-fertilization in a hermaphroditic animal

Sex-allocation theory predicts that the evolution of increased rates of self-fertilization should be accompanied by decreased allocation to male reproduction (sperm production and broadcast). This prediction has found support in plants but has not previously been tested in animals, which, in contrast to biotically pollinated plants, are free of complications associated with incorporating the costs of attractive structures such as petals. Here we report rates of self-fertilization as well as proportional allocation to male reproductive tissues within populations of the simultaneous hermaphrodite Utterbackia imbecillis, a freshwater mussel. Individuals from populations with higher selfing rates devoted a lower proportion of reproductive tissue to sperm production (correlation = -0.99), in support of theory.

Effect of nonaxisymmetric hematocrit distribution on non-Newtonian blood flow in small tubes

Hematocrit distribution and red blood cell aggregation are the major determinants of blood flow in narrow tubes at low flow rates. It has been observed experimentally that in microcirculation the hematocrit distribution is not uniform. This nonuniformity may result from plasma skimming and cell screening effects and also from red cell sedimentation. The goal of the present study is to understand the effect of nonaxisymmetric hematocrit distribution on the flow of human and cat blood in small blood vessels of the microcirculation. Blood vessels are modeled as circular cylindrical tubes. Human blood is described by Quemada's rheological model, in which local viscosity is a function of both the local hematocrit and a structural parameter that is related to the size of red blood cell aggregates. Cat blood is described by Casson's model. Eccentric hematocrit distribution is considered such that the axis of the cylindrical core region of red cell suspension is parallel to the axis of the blood vessel but not coincident. The problem is solved numerically by using finite element method. The calculations predict nonaxisymmetric distribution of velocity and shear stress in the blood vessel and the increase of apparent viscosity with increasing eccentricity of the core.

Unique organization of the CTX genetic element in Vibrio cholerae O139 strains which reemerged in Calcutta, India, in September 1996

We studied the restriction fragment length polymorphism of the rRNA gene and CTX genetic element in Vibrio cholerae O139 Bengal, which resurged in Calcutta in September 1996 after a gap of 32 months. While the strains from this resurgence were indistinguishable from the earlier strains by ribotyping, the structure of the CTX genetic element present in the current O139 strains was found to be unconventional.

Preferential interaction of a novel tumor surface protein (p38.5) with naive natural killer cells

A receptor-ligand interaction exclusive to natural killer (NK) cell-mediated recognition and triggering of tumor cell destruction has not yet been identified. In contrast, molecules that are involved in cellular adhesion and regulation of NK cytolysis have been well studied. In this report, a novel tumor surface protein is identified that exhibits characteristics of a recognition structure for naive NK cells. A tagged ligand-cell adsorption technique revealed a 38.5-kD plasma membrane protein (p38.5) from a prototypical NK-susceptible cell line (K562) that preferentially bound to NK cells (CD3(-)CD5(-)CD16(+)) relative to T lymphocytes (CD3(+)CD5(+) CD16(-)). The molecule was purified to apparent homogeneity for further characterization. An amino acid sequence of an 11-mer internal peptide of p38.5 did not exhibit homology to known proteins. Affinity-purified antibody generated against this peptide (anti-p38.5) reacted with a single protein of 38.5 kD on Western blots of whole cell extracts of K562. Flow cytometry and immunoprecipitation studies of surface-labeled tumor cells demonstrated expression of p38.5 on NK-susceptible tumor cell lines (K562, MOLT-4, Jurkat), whereas p38.5 was not detected on NK-resistant tumor cell lines (A549, Raji, MDA-MB-231). Significantly, p38.5 loss variants derived from wild-type Jurkat and Molt-4 cell lines exhibited decreased susceptibility to NK cell-mediated lysis demonstrating a strong association between cell surface expression of p38.5 and cytotoxicity. Purified p38.5 retained preferential binding to NK cells and inhibited NK activity in a dose-dependent manner, thereby providing direct evidence of a role in the lytic process. Binding studies identified a 70-kD membrane protein from NK cells as a possible receptor for the p38.5 tumor ligand. Consistent with cellular adsorption studies, the 70-kD, p38.5 binding protein was not detected on T lymphocytes. Based on studies demonstrating selective binding of p38.5 to NK cells, lack of expression on NK-resistant tumor cell lines and ability of the purified molecule to block cytolysis, we conclude that p38.5 may serve as a recognition/triggering ligand for naive human NK cells.

Ductus arteriosus aneurysm in the adult: role of computed tomography in diagnosis

Aneurysm of the ductus arteriosus has been reported in children more frequently than in adults [1-4]. The rarity of the lesion explains the low rate of recognition by the radiologist, especially because symptoms are non-specific in most cases. Clinically and radiologically, aneurysm of the ductal diverticulum can be confused with other mass lesions in the aorticopulmonary window. We report CT features of two ductal aneurysm in the adult with atypical presentation.