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Biomedical subjects

J R Patel

Publications and source records attributed to J R Patel.

At least 19 recordsLinked to original sources
PubMed1990

Calcium release from cardiac sarcoplasmic reticulum induced by photorelease of calcium or Ins(1,4,5)P3.

The ability of Ca2+ or inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] to release Ca2+ from cardiac sarcoplasmic reticulum (SR) was investigated using saponin-skinned ventricular trabeculae from rats. To overcome diffusion delays, rapid increases in the concentrations of Ca2+ and Ins(1,4,5)P3 were produced by laser photolysis of "caged Ca2+" (Nitr-5) and "caged Ins(1,4,5)P3". Photolysis of Nitr-5 to produce a small jump in [Ca2+] from pCa 6.8 to 6.4 induced a large and rapid force response (t1/2 = 0.89 s at 12 degrees C); the source of the Ca2+ that activated the myofibrils was judged to be the SR, since it was blocked by 0.1 mM ryanodine or 5 mM caffeine. A smaller, slower, and less consistent release of SR Ca2+ was produced by photorelease of Ins(1,4,5)P3. The results demonstrate that these caged compounds can be used to study excitation-contraction coupling in skinned multicellular preparations of cardiac muscle. The data are consistent with a major role for Ca2(+)-induced Ca2+ release in cardiac activation, whereas the role for Ins(1,4,5)P3 may be to modulate, rather than directly stimulate, SR Ca2+ release.

Animals↗
PubMed1989

The focal trough of the Autopan panoramic dental x-ray machine.

The focal trough of the Autopan machine was evaluated with a multiline test object. The width of the focal trough varied from 5.5 mm anteriorly to about 23 mm in the midramus area with 1.7 line pairs per millimeter of resolution. The focal trough covers most tooth position areas. The machine is capable of producing clinically acceptable radiographs in most clinic populations.

Equipment Design↗
PubMed1987

Characterisation of lymphoproliferative disease virus of turkeys. Structural polypeptides of the C-type particles.

Lymphoproliferative disease virus of turkeys (LPDV), a C-type retrovirus, was shown to contain 3 major [32 kilodaltons (kd, p 32), 26 kd, 22/21 kd] and 2 minor (41 kd and 12 kd) polypeptides. Preliminary evidence suggests a glycoprotein of 76 kd (GP 76) and a major doublet polypeptide of 13.5/13 kd to be also of viral origin. Of these GP 76 was susceptible to bromelain action implying its surface location in the virion, while p 32, p 26 and p 13.5/13 were the main constituents of viral cores. p 13.5/13 bound an RNA probe, suggesting it to be the main constituent of viral ribonucleoprotein. p 22/21 was not cleaved by bromelain, and was absent in viral cores suggesting its intramembrane location between virion envelope and core. The polypeptide profile of LPDV is distinct from those of avian sarcoma-leukosis viruses and avian reticuloendotheliosis viruses.

Animals↗
PubMed1987

Detection of lymphoproliferative disease virus by an enzyme-linked immunosorbent assay.

Hitherto, detection of lymphoproliferative disease virus (LPDV), a C-type retrovirus of turkeys, has proved difficult since no tissue culture or serological assay has been available. Development of serological tests has been hampered by the problems of raising virus-specific antisera. An indirect enzyme-linked immunosorbent assay (ELISA) is reported, using a viral antiserum raised with bromelain-digested virus. The assay specifically detected purified virus at a concentration of 250 ng/ml or greater. In an experiment to detect virus in plasma from turkeys over a period of 4 weeks following LPDV infection, ELISA results correlated closely with the viral reverse transcriptase activity. Both assays were of similar sensitivity and detected small amounts of virus in high-speed pellets of turkey plasma. Evidence is presented indicating that LPDV-infected or hyperimmunized turkeys do not produce readily detectable circulating viral antibodies. In reciprocal ELISA tests, using antibodies to group-specific antigens of other avian retrovirus groups (avian sarcoma-leukosis (ASLV) and reticuloendotheliosis (REV] no antigenic cross-reaction was found between LPDV, ASLV and REV.

Animals↗
PubMed1986

Endothelial cell infection and thrombosis in paralysis caused by equid herpesvirus-1: equine stroke.

Eight mares were infected with equid herpesvirus-1 subtype 1 isolated from a case of equine paresis. In two mares killed at 4 d.p.i. immunofluorescence showed endothelial cell infection together with thrombosis in the rete arteriosus of the nasal mucosa and also in the spinal cord of one of these mares. Circulating platelet counts in the other six mares fell as early as 2 d.p.i. and remained depressed for seven days. Circulating immune complexes started to appear at 2 d.p.i., reached maximum levels at 10 d.p.i., but were undetectable at 28 d.p.i. Three of the six remaining mares developed varying degrees of inco-ordination at 8 and 9 d.p.i. In the two inco-ordinate mares that were killed at 9 and 10 d.p.i. the haemorrhages in the spinal cord and brain were associated with extensive endothelial cell fluorescence and thrombus formation. Clinical paresis coincided with an increase in circulating complement fixing and neutralising antibodies which in all six mares were higher against the subtype 2 isolate than subtype 1. In five yearlings infected with a subtype 2 isolate of EHV-1 platelet counts remained normal and neither immune complexes nor viraemia, nor inco-ordination were detected.

Animals↗
PubMed1986

The horizontal plane in patient positioning for panoramic radiography.

The average angles between the horizontal and occlusal planes and the ala-tragus and orbito-meatal lines were measured for 96 patients in a panoramic x-ray machine. The angles required to produce clinically acceptable radiographs are described. Some operator judgment is required when positioning each patient's head for radiographs of optimum quality.

Adolescent↗
PubMed1986

Evaluating student progress through error reduction in intraoral radiographic technique.

A simple system was developed to collate the errors made when radiographic surveys are taken of the complete mouth. A radiographic critique form was used to evaluate each radiograph. This study used 1150 complete-mouth radiographic surveys made by junior dental students. From a total of 24,150 radiographs, 2238 were clinically unacceptable as a result of one or more errors in technique. No retakes caused by processing or mechanical errors were considered. The four major errors that were found in the study included cone cutting (11.17%), incorrect vertical angulation (11.75%), incorrect horizontal angulation (4.6%), and incorrect film placement (64.9%). Although expected, perhaps the most noteworthy finding was that there was a statistically significant difference between the performance of students during the first quarter as opposed to the third quarter of clinical training; this indicated the need for a minimum of twenty to twenty-five complete mouth radiographic surveys to achieve minimal technical proficiency.

Clinical Competence↗
PubMed1985

Densitometric evaluation of Soludent and GBX developers.

A quick-developing solution (Soludent) and a new developer (Kodak GBX) were compared with a standard x-ray liquid developer. Of the three solutions evaluated, Kodak GBX solution produced slightly greater useful densities in the radiograph at all temperatures evaluated. The rapid-developing solution produced acceptable radiographs in 80% less time, with only slightly higher film fog.

Absorptiometry, Photon↗
PubMed1985

A comparison of the susceptibility of three human gut tumour-derived differentiated epithelial cell lines, primary monkey kidney cells and human rhabdomyosarcoma cell line to 66-prototype strains of human enteroviruses.

The growth of prototype strains of 31 serotypes of ECHO, 3 polio, 6 Coxsackie B, 24 Coxsackie A and enterovirus serotypes 70 and 71 were tested in parallel in primary monkey kidney cells (PMK), RD cells and three gut tumour-derived differentiated epithelial cell lines (HRT-18 HT-29 in SKCO-1). All 31 serotypes of ECHO viruses grew in HT-29, 27 and SKCO-1, 5 in HRT-18, 29 in PMK and 29 in RD. There was good growth of poliovirus serotypes in all five cell types. Coxsackie B viruses grew well in all the cell lines except RD. Fifteen of the Coxsackie A viruses grew in SKCO-1, 4 in HT-29, 3 in HRT-18 and 7 in RD. Enterovirus serotypes 70 and 71 grew only in RD cells after 3 serial passages. These results showed that 2 of the gut tumour-derived cell lines, HT-29 and SKCO-1 had a markedly wider susceptibility, with comparable or wider sensitivity, for enteroviruses, than PMK and RD. While their use for field isolation from clinical samples is not yet fully established HT-29 and SKCO-1 would appear to be ideal for a variety of laboratory manipulations of the majority of enteroviruses.

Animals↗
PubMed1985

An epidemic of acute diarrhoea in rural southern India associated with echovirus type 11 infection.

An epidemic of diarrhoea with two distinct waves affected a village of 1375 people in southern India in 1983. The first wave of the epidemic, from the last week of December 1982, had a sharp peak in January 1983 and was over by March. Echovirus type 11 was isolated from patients, who also had a serum antibody response to the virus. During the second wave of the epidemic, from May to September 1983, the clinical features were different and Shigella flexneri was isolated without significant viral isolates. Infection during the first wave did not protect from the second wave. Virus isolation was in human intestinal tumour-derived differentiated epithelial cell lines; such cell lines may be useful for the isolation and identification of enteroviruses in clinical samples.

Diarrhea↗
PubMed1979

Intraoral radiographic errors.

The purpose of this investigation was to investigate intraoral radiography in regards to the frequency of errors, the types of error necessitating retakes, and the relationship of error frequency to the teeth area examined and type x-ray cone used. The present study used 283 complete mouth radiographic surveys made, and 890 radiographs were found to be clinically unacceptable for one or more errors in technique. Thirteen and one-tenth errors per one hundred radiographs were found in this study. The three major radiographic errors occurring in this study were incorrect film placement (49.9 percent), cone-cutting (20.8 percent), and incorrect vertical angulation (12.5 percent).

Dental Equipment↗
PubMed1979

Invasion of mouse brain by Mount Elgon bat virus.

Mount Elgon bat virus killed mice up to 13 days of age when given intranasally. Virus reached the brain of these mice via the olfactory nerve route without obvious multiplication in any tissues other than the nasal mucosa of 1- to 6-day-old mice and in the absence of viraemia or circulating virus neutralizing antibody. Large amounts of interferon were, however, synthesized in brain where virus grew to high titres. In mice older than 13 days virus did not multiply in brain but it reached the olfactory bulbs and persisted until virus neutralizing antibody appeared in the nasopharynx. No antibody was detected in blood of the resistant mice, nor was interferon detected in their brains or nasal mucosa. Immunosuppression of the resistant mice with cyclophosphamide resulted in moderate virus growth in mid- and hind-brain accompanied by interferon synthesis and death of the mice. The local immune response prevented invasion of mid- and hind-brain in the resistant mice.

Animals↗
PubMed1979

The pathogenesis of infection in mouse brain by Mount Elgon bat virus.

Mount Elgon bat virus given intracerebrally readily killed mice up to 12 days of age (1 to 4 p.f.u/LD50). Virus in doses of 10 to 10(6) p.f.u. killed 40 to 80% of weanling mice of both sexes and up to 20% of adult females and 40 to 80% of adult males. Clearance of brain infectivity in the resistant mice coincided with the appearance of circulating virus neutralizing antibody which occurred earliest in the adult female mice. Immunosuppression of adult mice with cyclophosphamide resulted in the death of all the virus-inoculated mice of both sexes. Virus in these mice reached tenfold higher titres and their brains contained 30- to 60-fold more interferon than the brains of infected mice not given cyclophosphamide. Interferon was apparently without effect on the outcome of infection in the brains of resistant mice and its synthesis reflected the extent of virus growth.

Animals↗
PubMed1978

Mass spectra of the oxygenated products generated from phenanthrene under simulated environmental conditions.

The photooxidation of phenanthrene under stimulated environmental conditions to 9,10-epoxy-9,10-dihydrophenanthrene, among other oxygenated products, serves as a model for the conversion of polycyclic aromatic hydrocarbons to potentially mutagenic and/or carcinogenic products. The separation and identification were achieved by glass capillary gas chromatography mass spectrometry, and by comparison of gas chromatographic retention times and mass spectral fragmentation patterns with data observed for authentic samples obtained independently through synthesis or from commercial sources. The structural rearrangements of 2,2'-di-substituted biphenyls such as 2-formyl biphenyl-2'-carboxylic acid, 2,2' diformyl biphenyl and diphenic acid anhydride, induced upon electron impact are investigated and discussed in detail. The mass spectral comparison of 9,10-epoxy-9,10-dihydrophenanthrene, a primary mammalian metabolite of phenanthrene, and certain other structural isomers was conducted and the results of this study suggest a mass spectral technique capable of differentiating arene oxides from oxepin, phenol and carbonyl isomers. A discussion of the potential impact of the sensitized photooxidation of more condensed environmental polycyclic aromatic hydrocarbon pollutants is presented and the role of bioactive arene oxides produced under such photooxidation conditions is also discussed. Related oxides of polycyclic aromatic hydrocarbons are known to be proximate carcinogens and/or mutagens generated by metabolic activation. The role and significance of solar induced oxidation in the weathering of petroleum hydrocarbons at air-sea interfaces and the incorporation of potentially bioactive organic residues in the food chain are also addressed.

Biphenyl Compounds↗