PubMed Health⌕ Search

Biomedical subjects

B K Patel

Publications and source records attributed to B K Patel.

106 records · Page 6Linked to original sources
PubMed1994

Isolation and characterization of Halothermothrix orenii gen. nov., sp. nov., a halophilic, thermophilic, fermentative, strictly anaerobic bacterium.

The occurrence of thermophilic, halophilic anaerobic bacteria in the sediment of a Tunisian salted lake was tested in samples collected at 20-cm intervals down to a depth of 1.20 m. A long rod, present only in the 40- to 60-cm layer, was isolated at 60 degrees C in a medium containing 100 g of NaCl per liter and designated strain H168. This strain produced acetate, ethanol, H2, and CO2 from glucose metabolism. Fructose, xylose, ribose, cellobiose, and starch were also oxidized. The optimum temperature for growth was 60 degrees C. No growth was obtained at 42 or 70 degrees C. Strain H168 grew optimally in NaCl concentrations ranging from 50 to 100 g per liter, with the upper and lower limits of growth around 200 and 40 g per liter, respectively. The G+C ratio of the DNA was 39.6 mol%. Although halophilic, moderately thermophilic bacteria have been characterized among anaerobes, particularly within methanogens, strain H168 is the first true thermophilic (growing above 60 degrees C) halophilic anaerobic bacterium described so far. The phylogeny, physiology, morphology, lipid content, and high G+C content of strain H168 are sufficiently different from those of genera belonging to the family Haloanaerobiaceae to justify the definition of a new genus.

Bacteria, Anaerobic↗
PubMed1993

Phylogenetic analysis of Desulfotomaculum thermobenzoicum using polymerase chain reaction-amplified 16S rRNA-specific DNA.

The 16S rRNA gene of the thermophilic sulfate-reducing bacterium Desulfotomaculum thermobenzoicum was amplified by polymerase chain reaction using two eubacterial consensus oligodeoxynucleotide primers flanking the majority of the 16S rRNA gene, cloned, and sequenced. Phylogenetic analysis revealed that D. thermobenzoicum belongs to the Gram-positive (low G + C content) branch and is more related to the thermophilic sulfate-reducing bacterium, D. australicum than the moderate thermophile D. nigrificans, or the mesophiles D. orientis, and D. ruminis. This relationship is further strengthened by the presence of an unusual idiosyncrasy in helix 6 of the 16S rRNA gene of D. thermobenzoicum resembling that of D. australicum but not found in other desulfotomacula species and in any other bacteria sequenced to date.

Bacillaceae↗
PubMed1993

Nucleotide sequence analysis of c-raf-1 cDNA and promoter from a radiation-resistant human squamous carcinoma cell line: deletion within exon 17.

The c-raf-1 proto-oncogene is the cellular homologue of v-raf, the oncogene of the acutely transforming retrovirus 3611-MSV. The product of c-raf-1 (raf-1) is a 74-kDa cytoplasmic serine/threonine protein kinase. We previously reported that antisense human c-raf-1 cDNA transfection results in reduction of the endogenous c-raf-1 transcript, decreased tumor growth rate, and enhanced radiation sensitivity of SQ-20B tumor cells established from a radiation-resistant laryngeal squamous cell carcinoma. In the study reported here, we used cDNA-linked polymerase chain reaction amplification and nucleotide sequencing to examine the structure of the 3233-bp SQ-20B c-raf-1 cDNA. The 812-bp c-raf-1 promoter region was analyzed by genomic DNA amplification followed by cloning and sequencing. Sequence comparison with a previously published c-raf-1 sequence indicated no structural changes within the coding region of SQ-20B c-raf-1. However, a 4-bp deletion was observed in the 3' untranslated region within exon 17. This deletion was also present in a c-raf-1 cDNA clone isolated from a SQ-20B cDNA library. While the possibility of a 3' transcriptional control mechanism cannot be ruled out, it appears that the raf-1 protein kinase may regulate the development of radioresistant malignancies via interaction with other molecules in the damage and repair-related signal transduction pathways.

Base Sequence↗
PubMed1991

Isolation of strains of Thermus aquaticus from the Australian Artesian Basin and a simple and rapid procedure for the preparation of their plasmids.

Thirty four Thermus aquaticus strains have been isolated from the non-volcanically naturally heated waters of the Australian Artesian Basin which extends the known ecological habitat of this group of organisms. A simple and rapid method developed for isolation of plasmids indicated that considerable variation in numbers and molecular sizes existed within the 23 strains that were investigated. Dissimilar plasmid profiles were obtained from the strains that been isolated from the source waters and those that had been isolated from the runoff channels formed by these source waters.

Australia↗
PubMed1991

Characterization of the heat shock response in Mycobacterium bovis BCG.

We have for the first time characterized the heat shock response in mycobacteria both at the level of transcription, by RNA extraction, Northern (RNA) blotting, and hybridization with gene-specific probes for the Mycobacterium tuberculosis 65- and 71-kDa heat shock proteins (HSPs), and at the level of translation, by [35S]methionine labelling, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and autoradiography. We observed increased synthesis of 40-, 65-, 71-, and 90-kDa proteins, which appear to be major HSPs in mycobacteria. The 40-, 71-, and 90-kDa HSPs are coordinately regulated in terms of temperature requirements and kinetics of induction but differ in the levels of expression. The 65- and 71-kDa HSPs are differentially regulated in response to temperature, with different kinetics and levels of induction. mRNA transcript sizes for the 71-, 65-, 40-, and 30-kDa proteins were found to be broadly consistent with DNA sequence open reading frames. A maximum increase of about 69-fold in the levels of mRNA for the 71-kDa HSP after 45 min of heat shock at 45 degrees C was observed, whereas the 65-kDa HSP mRNA increased only 5-fold. It was also found that in M. bovis BCG, as in Escherichia coli, a major control mechanism of the heat shock response is operative at the level of transcription. An ability to characterize the heat shock response in mycobacteria provides an experimental model with which to study environmentally regulated gene expression and an opportunity to identify virulence genes, which may coregulate as part of the heat shock regulon.

Blotting, Northern↗
PubMed1991

Fluid collections developing after pancreatic transplantation: radiologic evaluation and intervention.

The usefulness of real-time sonography, duplex sonography, computed tomography (CT), cystography, diagnostic aspiration, and percutaneous drainage in the diagnosis and treatment of peri-pancreatic-transplant fluid collections was retrospectively assessed in 46 recipients of extraperitoneal pancreatic transplants. Forty-four abnormalities were identified in the extraperitoneal space at sonography, including four pancreatic pseudocysts associated with malfunction of the pancreatic duct, seven abscesses, six hematomas, nine urinomas, six early postoperative fluid collections that spontaneously resolved, six cases of pancreatitis, and six cases of vascular occlusion. Sonography (including pulsed Doppler sonography) was the procedure of choice in detecting fluid collections and diagnosing pancreatitis, rejection, vascular thrombosis, and pancreatic duct malfunction. CT was diagnostic in four of six hematomas; cystography was diagnostic in seven of nine urinomas. Sonographically guided percutaneous intervention enabled three patients to avoid surgery and allowed optimal surgical planning for six patients.

Abscess↗
PubMedDate not supplied

Effect of thiosulphate as electron acceptor on glucose and xylose oxidation by Thermoanaerobacter finnii and a Thermoanaerobacter sp. isolated from oil field water.

During glucose and xylose fermentation, Thermoanaerobacter finnii was observed to produce lactate, acetate, H2 and CO2, with ethanol being the major end product. Thermoanaerobacter strain SEBR 5268, an isolate from an oil field, also produced a similar range of end products from glucose and xylose fermentation, with the exception that both ethanol and lactate were the major products of sugar metabolism. Both these strains were able to reduce thiosulphate to sulphide in the presence of these two substrates, with acetate being the dominant metabolite in that case. In addition, a faster growth rate and increased cell yield were obtained in the presence of thiosulphate, than in its absence. The higher concentrations of acetate produced in the presence of thiosulphate rather than without any electron acceptor indicated that more ATP was generated from substrate-level phosphorylation. These results have implications for our understanding of the breakdown of carbohydrates present in organic matter found in the natural ecological niches of Thermoanaerobacter species (sulphide-, elemental sulphur- or sulphate-rich thermal hot springs and oil fields).

Acetates↗
PubMedDate not supplied

Diagnostic accuracy of a teleradiology image transmission system.

Teleradiology is the remote interpretation of digitized radiographic images by physicians. The images are usually transmitted over telephone lines, but satellite communication has also been used. The interpretability of the transmitted image is an important factor in the operation and use of teleradiology systems. Commercially available equipment has certain built-in functions that may enhance the interpretability of the image received. These functions and their usefulness in diagnosis are described. It is also possible to enhance the image for transmission, prior to digitizing, by certain manual techniques. These may be of value in situations where the first transmission is lacking in some quality. A test of these functions and techniques is reported.

Diagnostic Imaging↗
PubMedDate not supplied

X-File: a program for maintaining a radiographic teaching file.

Software designed for entry, retrieval, and maintenance of radiographic case-file data on a microcomputer offers considerable help in maintaining such records in a radiology department. The case files are based on the Index for Roentgen Diagnoses, published by the AmericanCollege of Radiology. The terms and code numbers of the index are included in the software, so that the user need only enter the diagnostic term desired; the code numbers and exact terminology are assigned automatically. The software is written for an IBM-compatible microcomputer. Residents and staff radiologists have been using the program for the past two years to store and find both confirmed cases and other interesting cases. The system's capacity exceeds 70,000 entries on a 20-megabyte had disk. The program has five features not found in previous similar programs and not attainable with manual methods.

Hospital Information Systems↗