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Biomedical subjects

R Patel

Publications and source records attributed to R Patel.

At least 343 records · Page 19Linked to original sources
PubMed1987

The human Mr 90,000 heat shock protein and the Escherichia coli Lon protein share an antigenic determinant.

1. A monoclonal antibody (TG7A) reacts with a Mr 90,000 mammalian protein, accumulating during virus infection and heat shock. 2. This protein is encoded by a member of the Mr 90,000 heat shock gene family present in a range of organisms form yeast to man. 3. The antibody also recognises a Mr 94,000 protein in E. coli which similarly accumulates in virus infection and heat shock. 4. This protein has been identified as the Lon protease of E. coli. 5. The shared epitope and similar stress inducibility of the two proteins suggests that a functional and/or evolutionary relationship exists between them.

ATP-Dependent Proteases↗
PubMed1987

Sleep-disordered breathing in healthy aged persons: possible daytime sequelae.

We assessed the overnight sleep and breathing as well as daytime medical, sleep, and psychological status of a group of 34 healthy older persons. Analyses indicated that sleep-disordered breathing (SDB) was not related to any aspects of daytime functioning as measured in this study and that persons with an apnea + hypopnea index (AHI) greater than or equal to 5 (M AHI = 14.6) were not significantly impaired relative to those with lower levels of SDB (M AHI = 1.0) on any aspect of daytime performance. We conclude that SDB occurring in healthy aged persons is probably not of immediate concern and that the use of a cutting score of AHI greater than or equal to 5 for diagnosis of sleep apnea syndrome is not indicative in healthy aged persons. However, these results may not be applicable to older persons who are not in the excellent state of health that was required for participants in our study.

Aged↗
PubMed1987

In-hospital mortality rates from acute myocardial infarction by race in U.S. hospitals: findings from the National Hospital Discharge Survey.

Mortality rates in the United States from coronary artery disease are higher among blacks than whites at younger ages, with a crossover to lower rates above the age of 70. The factors that determine this crossover of age-specific death rates have not been elucidated. Selection from the black population of younger individuals who are sicker by virtue of being more coronary prone might leave a relatively healthier group of older persons. Support for this hypothesis would consist in part of evidence that coronary artery disease has an earlier onset in the black population. We examined data from the National Hospital Discharge Survey for the years 1973-1984 to determine if age-related differences in case-fatality rates existed between whites and nonwhites. In-hospital case fatality rates were 10% to 70% higher for each of the 10 year age groups for nonwhites up to age 70, at which time a crossover occurred. The median age at death from myocardial infarction was approximately 5 years younger in nonwhites compared with whites. National estimates of hospitalization rates for myocardial infarction from these data likewise suggest that nonwhites receive less health care for coronary artery disease than whites relative to recorded fatal events. The age-specific trends in case-fatality support the hypothesis that a cohort selection effect in part determines the black/white differentials in coronary artery disease. Relative susceptibility of the black and white population is thus not appropriately estimated by age-adjusted rates, but should be examined on an age-specific basis within the framework of selection effects on a cohort.

Adult↗
PubMed1986

Isolation of cDNA clones derived from a cellular gene transcriptionally induced by herpes simplex virus.

A small number of cellular proteins accumulate to high levels in cells infected with Herpes Simplex Virus (HSV) despite a generalised repression of most host cell bio-synthesis. An antibody to one such protein has been used to screen a lambda gt11 library and for polysome immunoprecipitation in order to isolate cDNA clones derived from the corresponding gene. The cDNA clones have been used in dot blot and nuclear run-off assays to show that HSV, like other DNA tumour viruses can transcriptionally induce a cellular gene. The mechanism of this effect which is dependent on viral protein synthesis and its possible significance in transformation by HSV are discussed.

Animals↗
PubMed1986

Pleomorphism of fine structure of rabies virus in human and experimental brain.

Identification of the Negri bodies in the brain of an 8-year-old boy who died 8 days after a paralytic illness and 20 days after a dog bite, and who had received 9 injections of Semple's anti-rabies vaccine, provided evidence that he died of acute rabies encephalitis and not of post-vaccinal allergic encephalomyelitis. The Negri bodies in the human subject and those seen in the inoculated mouse differed in their morphological structure: the former consisted of a matrix of very fine granular material bearing larger granules or strands of higher electron-density resembling nucleic acids and representing products of host cell-virus interaction; and the latter showed better defined areas of granular matrix containing tubular, bullet-shaped and elongated forms of viral structures, and nucleocapsids or capsule-deficient cores, representing the virions, emerging from them. Fine structural examination of the patient's brain and of the inoculated mouse has provided evidence of the pleomorphism of the Negri bodies and the various stages of formation of viral material and virions in them, the animal alone showing the mature virions of rabies, and proving the infectivity of the Negri bodies of the human brain.

Animals↗
PubMed1986

Isolation and restriction endonuclease analysis of mycobacterial DNA.

A method for the isolation of DNA from mycobacteria propagated in vitro is described that utilizes organic solvents to extract lipoidal components from the outer membrane, and digestion with a protease (nagarse) and lysozyme to penetrate the cell wall. The mycobacterial cells were lysed by the addition of detergent and the DNA was purified by digestion with pronase, sequential phenol and chloroform extractions, and digestion with RNAase A. The isolated DNA, which was obtained in good yields, was of a relatively high Mr and could be readily digested by restriction endonucleases. By this method, the genomes of Mycobacterium avium, M. intracellulare, M. lepraemurium, 'M. lufu', M. marinum, M. phlei, M. scrofulaceum, M. smegmatis and M. tuberculosis were isolated and the restriction endonuclease digestion patterns analysed. Each species could be distinguished by the digestion patterns, indicating that this approach can be used for identifying mycobacterial species. This approach is also sufficiently sensitive to differentiate strains since we were able to distinguish two independently isolated strains of M. tuberculosis, H37 and H4. In addition, no evidence was obtained for the presence of methylcytosine residues in the sequences 5'.CCGG.3',5'.CCCGGG.3',5'.CC(A/T) GG.3' or for methyladenine at 5'.GATC.3' in the DNA of the nine mycobacterial species examined using pairs of restriction enzymes that recognize and cleave at the same nucleotide sequence but differ in their sensitivity to 5-methylcytosine or 6N-methyladenine.

DNA Restriction Enzymes↗
PubMed1986

T cell subsets in idiopathic glomerulonephritis.

Determination of T lymphocyte subsets using monoclonal antibodies revealed a deficiency of suppressor cells and an elevated helper:suppressor T cell ratio in 7 patients with untreated idiopathic immune complex glomerulonephritis and nephrotic syndrome. Possible pathogenetic mechanisms of immunoregulatory cell imbalance and their implications specifically in reference to idiopathic glomerulonephritis are discussed.

Adult↗
PubMed1986

Neurotoxicity associated with systemic high-dose cytosine arabinoside.

High doses of cytosine arabinoside (ara-C) have been used in the treatment of refractory forms of acute nonlymphoblastic leukemia (ANLL) and ANLL occurring after previous antineoplastic therapy. In addition to the usual toxicities associated with antimetabolites, neurotoxicity, mainly in the form of cerebellar dysfunction, develops in a significant proportion of patients receiving high-dose cytosine arabinoside HDara-C. This study was performed to determine the incidence of cerebellar dysfunction in our patients and to determine any factors that predict its development. In this series of 30 consecutive patients receiving HDara-C, confusion with cerebellar signs and symptoms developed in seven (23%). Factors that appear to predispose patients to the development of neurotoxicity are (1) past history of neurologic dysfunction and (2) preexisting and progressive hepatic dysfunction. No peripheral neuropathy was seen. In contrast to previous reports, we did not find neurotoxicity to be dose related. Prophylactic use of pyridoxine does not prevent neurotoxicity.

Acute Disease↗
PubMed1986

Technetium-99m pyrophosphate imaging in acute renal failure associated with nontraumatic rhabdomyolysis.

Technetium-99m pyrophosphate (Tc-PYP) imaging was performed in five patients with acute renal failure associated with nontraumatic rhabdomyolysis. Four patients had phencyclidine intoxication and one had viral pneumonia. During the acute phase, marked uptake of pyrophosphate was seen in all patients in several muscle groups, but always in the thigh adductors. The results show that phencyclidine intoxication can result in diffuse muscle uptake of Tc-PYP without overt evidence of muscle injury. Tc-PYP imaging may provide a clue to the cause of acute renal failure in patients with suspected rhabdomyolysis in whom elevations of serum creatine phosphokinase concentrations are equivocal.

Acute Kidney Injury↗
PubMed1986

Renal disease associated with toluene inhalation.

A 32-year old woman developed severe quadriparesis, hypokalemia, and distal renal tubular acidosis following paint sniffing for one week. A review of literature indicated that a spectrum of renal diseases may develop in association with inhalation of toluene-containing substances. Toluene inhalation should be considered in the differential diagnosis in any young patient who presents with an unexplained renal disorder.

Acidosis, Renal Tubular↗
PubMed1986

T lymphocyte subsets and antilymphocyte antibodies in lupus nephritis.

T lymphocyte subsets were determined in 12 patients with untreated systemic lupus erythematosus (SLE) and in 14 healthy controls. Six out of 8 (75%) patients with lupus nephritis had reduction in the percentage of T helper cells and low helper: suppressor cell ratios compared with controls. None of the 4 patients without nephritis had low ratios. Cold-reactive anti-lymphocyte antibodies cytotoxic to both the helper and the suppressor cells were detected in 7 of the 8 patients who had nephritis. Low T helper: suppressor cell ratio in SLE seems to correlate with the presence of active nephritis.

Adult↗
PubMed1986

Migration of neuroblasts along preexisting axonal tracts during prenatal cerebellar development.

During prenatal development of the cerebellum in rats, a secondary stem cell layer, the external granular, or germinal, layer (EGL) develops at the pial surface of the cerebellar anlage. The EGL cells arise in a region at the caudolateral margin of the fourth ventricle, and the cells migrate over the surface of the developing cerebellum. A key question is how this migration is guided. We have investigated the possible role of the extracellular matrix protein, fibronectin, and find none present in the EGL during the migration. Instead, we find that the EGL neuroblasts migrate in close contact with axons that are present prior to the onset of migration. It appears that these axons serve as the substrate for EGL neuroblast migration and that axonal guidance of cell migration may be a third general mechanism to be added to the previously studied guidance by glial processes and extracellular matrix.

Animals↗
PubMed1986

Is reactive gliosis a property of a distinct subpopulation of astrocytes?

We have shown previously that the A2B5 monoclonal antibody distinguishes two types of glial fibrillary acidic protein-containing astrocytes in semithin frozen sections of adult rat optic nerve: A2B5- (type-1) astrocytes are found mainly at the periphery of the nerve, where they form the glial limiting membrane, while A2B5+ (type-2) astrocytes are found mainly in the interior of the nerve and constitute more than 65% of the astrocytes in the adult optic nerve. In the present study we show that although most astrocytes in semithin frozen sections of adult rat corpus callosum and optic nerve are A2B5+, the great majority of reactive astrocytes in similar sections of corpus callosum examined 20 weeks after a stab lesion, and in optic nerve examined 20 weeks after adult transection, are A2B5-. Although both A2B5+ and A2B5- astrocytes are stimulated to synthesize DNA in the first week after transection, adult optic nerves examined 20 weeks after transection contain only half as many astrocytes as do normal optic nerves: While A2B5+ astrocytes are reduced almost 10-fold, A2B5- astrocytes are increased by about 25%. We consider the simplest interpretation of these findings to be that type-1 astrocytes are largely responsible for forming glial scars in adult white matter following either a stab lesion or Wallerian degeneration and that in transected optic nerves, most type-2 astrocytes eventually die, possibly because they depend on axons for their long-term survival.

Animals↗
PubMed1986

Cefonicid, a long acting cephalosporin: in vitro activity compared with three cephalosporins and gentamicin.

Minimum inhibitory concentrations of cefonicid, cefazolin, cefuroxime, ceftazidime and gentamicin were determined against 688 bacterial strains (234 Gram-positive and 454 Gram-negative) from 20 different genera. Cefonicid showed a broader spectrum than cefazolin but was not as active as ceftazidime or gentamicin. Cefonicid most closely resembled cefuroxime in terms of microbiological properties. Disc testing accurately predicted sensitivity to cefonicid except for Staphylococcus aureus (which was sensitive by MIC, but appeared resistant in the disc test) and Proteus vulgaris (which was resistant by MIC but appeared sensitive in the disc test). In combination with gentamicin, synergy or addition was observed in 94% of 35 strains tested by the chequerboard technique. In view of its long half-life and wide range of microbiological activity, cefonicid promises to be a useful addition to the range of cephalosporins already available.

Cefamandole↗