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Biomedical subjects

B Patel

Publications and source records attributed to B Patel.

At least 181 records · Page 10Linked to original sources
PubMed1987

Corticosteroid-responsive pure red cell aplasia in chronic lymphatic leukemia.

Acquired pure red cell aplasia characterized by selective failure of erythropoiesis was seen in a 37-yr-old female patient with a diagnosis of chronic lymphatic leukemia (CLL). Though different immunosuppressive therapies have been tried in the past with variable response, there has been no case report of such favorable response to corticosteroids alone. We report this rare and unusual case of PRCA associated with CLL who responded to steroid therapy.

Adult↗
PubMed1987

Evaluation of bone scan as a screening work-up in primary and local-regional recurrence of breast cancer.

To evaluate the use of radionuclide bone scan in staging patients with primary and local-regional recurrence of breast cancer, we reviewed the results in 265 patients with primary breast cancer who had the scan either preoperatively or within 6 weeks of surgery, and in 39 patients presenting with their first local-regional recurrence. All patients were clinically staged according to the revised 1983 criteria of the American Joint Committee for Cancer Staging and End-Results Reporting. None of the 92 with stage I and four of 95 patients with stage II had a positive scan. Eleven of 41 with stage IIIA and 13 of 37 with stage IIIB had a positive bone scan. In patients with their first local-regional recurrence, 12 of 39 had a positive scan. Follow-up scans were available in 61 patients with clinical stage I and II breast cancer who had adjuvant chemotherapy for pathological involvement of axillary node. There were six conversions observed in 61 scans obtained during the first year. Seven converted in follow-up scans in 47 patients in the second year. We conclude that although bone scans have a low positive yield in stage I and II breast cancer, their use in the preoperative setting and in the follow-up of patients with axillary node involvement detects early converters. Bone scans are justified in stage IIIA and IIIB breast cancer and in patients being evaluated for local-regional recurrence.

Adult↗
PubMed1987

5-Fluorouracil cardiotoxicity: left ventricular dysfunction and effect of coronary vasodilators.

Seven patients developed clinical features simulating myocardial ischemia less than 72 hours after 12 of 13 separate intravenous 5-fluorouracil administrations; 9 episodes were associated with chest pain, 3 with hypotension, 3 with ventricular tachycardia and 1 with cardiogenic shock. Left ventricular dysfunction was demonstrated by echocardiography in 5 separate episodes, 2 with interval improvement upon repeat echocardiograms. Pretreatment with nitrates and/or calcium channel blockers failed to prevent recurrence of cardiotoxicity during 5 of 6 repeat 5-fluorouracil administrations. Therapy with 5-fluorouracil is associated with cardiotoxicity simulating myocardial ischemia with left ventricular dysfunction. Pretreatment with coronary vasodilators may not prevent this phenomenon.

Aged↗
PubMed1987

Morphological and immunocytochemical identification of indoleamine-accumulating neurons in the cat retina.

The type and distribution of indoleamine-accumulating neurons were studied in the cat retina. The neurons were characterized by their capacity to take up an exogenous indoleamine, 5,6-dihydroxytryptamine, which could then be visualized using formaldehyde-induced fluorescence. Under direct microscopic control, intracellular injection of Lucifer yellow into the labeled cells revealed that the indoleamine-accumulating neurons comprise 2 distinct morphological types of amacrine cell and 1 class of ganglion cell. The dendritic morphology and retinal distribution of these cells were studied in detail. The proportion of retinal cells that accumulate 5-HT was measured using 5-HT (5-hydroxytryptamine) preloading in vitro and immunocytochemistry with an anti-5-HT antibody. Only 1 type of amacrine cell showed uptake of 5-HT at a concentration of 10(-7) M. Cells containing endogenous 5-HT were not detected by immunocytochemistry.

5,6-Dihydroxytryptamine↗
PubMed1987

Protein C abnormalities in spinal cord injured patients with end-stage renal disease.

Patients with chronic spinal cord injury (SCI) and end-stage renal disease (ESRD) exhibit antithrombin III deficiency and several other coagulation abnormalities. In view of increasing recognition of protein C (PC) as an important, naturally occurring anticoagulant and fibrinolytic factor, we studied plasma PC in this population. PC antigen concentration and its anticoagulant activity were measured in nine SCI men with ESRD maintained on hemodialysis and in a control group of ten normal able-bodied men. The results showed a significant increase in PC anticoagulant activity in the SCI group. Consequently, the ratio of the PC activity to its concentration, which is a measure of the functional integrity of PC molecule, was markedly depressed. These findings are indicative of the presence of inactive or abnormal PC in SCI-ESRD patients and may suggest its in vivo activation. The combination of impaired PC activity shown in this study, with previously demonstrated antithrombin III deficiency and other coagulation abnormalities, is suggestive of a hypercoagulable state.

Adult↗
PubMed1986

Hydrolysis of nicotinyl 6-aminonicotinate.

The degradation kinetics of nicotinyl 6-aminonicotinate in aqueous buffer solutions were studied over the pH range from 4.0 to 10.0. In all cases, pseudo-first-order kinetics were observed at constant hydronium ion concentration. The pH-rate profile indicated that the hydrolysis of nicotinyl 6-aminonicotinate may be described by at least two catalytic terms. In alkaline solution the hydrolysis is catalyzed primarily by hydroxyl ions. In acidic solution the hydrolysis may be attributed to either the water-catalyzed reaction of the protonated species or the hydronium ion catalyzed reaction of the free base. The resulting catalytic profile afforded a sharp pH minimum of approximately 5.90 at 65 degrees C. An activation energy of 16 Kcal/mol was obtained in a phosphate buffer solution at a pH of approximately 5.90 +/- 0.2. The first- and second-order reaction constants for water and hydroxyl ion catalysis were determined, and the temperature dependency of the reaction was studied. The buffer effect and solvent effect on the hydronium and hydroxyl ion catalysis was also investigated.

Buffers↗
PubMed1986

The use of Rous sarcoma virus transformation mutants with differing tyrosine kinase activities to study the relationships between vinculin phosphorylation, pp60v-src location and adhesion plaque integrity.

Tyrosine-specific phosphorylation of cellular proteins has been implicated in the neoplastic transformation of cells by Rous sarcoma virus (RSV). One of the putative substrates for the src gene product (pp60v-src) of RSV is the cytoskeletal protein vinculin, giving rise to the hypothesis that tyrosine-specific phosphorylation of vinculin disrupts adhesion plaque integrity, leading to the characteristic rounded morphology of RSV-transformed cells. We have investigated this hypothesis by analysing the properties of fibroblasts transformed by conditional and non-conditional mutants of RSV which confer different morphologies on infected cells, with respect to formation of microfilament bundles, formation of vinculin-containing adhesion plaques, the deposition of a fibronectin-containing extracellular matrix, the localization of pp60v-src and the tyrosine-specific phosphorylation of vinculin. Cells transformed by the temperature-sensitive (ts) RSV mutant LA32 cultured at 41 degrees C were morphologically normal, and contained prominent microfilament bundles and well-developed adhesion plaques. However, these cells had a fully active pp60v-src kinase, had pp60v-src concentrated in their adhesion plaques and contained vinculin which was heavily phosphorylated on tyrosine residues. Cells transformed by a recovered avian sarcoma virus, rASV 2234.3 exhibited a markedly fusiform morphology with pp60v-src concentrated in well-developed adhesion plaques and an elevation of the phosphotyrosine content of vinculin. Cells transformed by LA32 at restrictive temperature comprise morphologically normal cells, indistinguishable from untransformed CEF, yet which contain tyrosine-phosphorylated vinculin and suggest that neither tyrosine-specific phosphorylation of vinculin nor pp60v-src concentration in adhesion plaques is sufficient for the rounded morphology of RSV-transformed cells.

Avian Sarcoma Viruses↗
PubMed1986

Anthralin stain removal.

Results of an anthralin stain removal study on white 65% polyester/35% cotton, white 100% polyester, white 100% cotton, a white shower curtain, white tile with crevice, and white ceramic shower tile are reported. An optimum stain removal technic was developed by using a 10-minute soak in full-strength chlorine bleach (Good Measure or Clorox) followed by a water rinse and air drying. This technic completely removed all stains of 24-hour duration from the test fabrics. The stain removal test on shower curtains, floor tiles, and ceramic shower tiles was also discussed.

Anthralin↗
PubMed1986

Increase in the number of type II insulin-like growth factor receptors during propylthiouracil-induced hyperplasia in the rat thyroid.

We have observed that membranes isolated from rat thyroids contain receptors for the insulin-like growth factors (IGF). As IGFs are known to be important mediators of tissue growth, we conducted this study to determine whether modulation of thyroid IGF receptors might be involved in TSH-stimulated hyperplasia. A substantial increase in both the weight of the thyroid and its DNA content was observed within 2 days of exposing adult male rats to 0.1% propylthiouracil (PTU) in their drinking water. Serum T4 reached unmeasurable levels and serum TSH rose 3-fold over control by the tenth day of treatment. [125I]Iodo-human(h)IGF-II binding to membranes isolated from hyperplastic glands was significantly higher than control beginning at 2 days. A maximum was reached after 5 days (13.3 +/- 0.8%/25 micrograms protein vs. a control level of 6.7 +/- 0.7%, mean +/- SEM). The increase had disappeared by 15 days of PTU exposure, paralleling the drastic fall in the growth rate of the glands. This increase in binding was specific for the thyroid, as it was not seen in other organs. In both treated and control animals, the receptor involved was shown to be type II by preferential binding to IGF-II, lack of interaction with insulin, and molecular sizing. The observed increase in binding could be accounted for by an increase in receptor site number, the affinity remaining essentially the same. We conclude that the TSH-stimulated hyperplasia of the rat thyroid, induced by PTU, is associated with an increase in the binding sites of the type II IGF receptor. This observation raises the possibility that modulation of this receptor may play a role in the mediation of the mitogenic effect of TSH on the thyroid gland.

Animals↗
PubMed1986

Comparison of the relative importance of tyrosine-specific vinculin phosphorylation and the loss of surface-associated fibronectin in the morphology of cells transformed by Rous sarcoma virus.

We have investigated the relative importance of tyrosine-specific phosphorylation of vinculin and the loss of surface-associated fibronectin in the maintenance of the rounded morphology characteristic of chick embryo fibroblasts (CEF) transformed by Rous sarcoma virus (RSV). To address this question we have examined the interaction of CEF and RSV-CEF in vitro with exogenously added fibronectin in both 3-day culture experiments and short-term, 3-h spreading experiments. We report that the addition of human plasma fibronectin to cultures of RSV-CEF results in the restoration of a near-normal morphology, as has been described previously, with the added fibronectin incorporated into an extracellular matrix. However, the phosphotyrosine content of vinculin in these cells was unchanged from that of control, untreated RSV-CEF despite the change in morphology. In short-term spreading experiments RSV-CEF were unable to adopt a fully spread morphology on fibronectin substrates, with defects in the formation of adhesion plaques and microfilament bundles compared with untransformed CEF. pp60v-src was present in the newly formed adhesion plaques of RSV-CEF spreading on fibronectin substrates. The relevance of these results to the maintenance of the transformed phenotype is discussed.

Animals↗
PubMed1985

Can a sponge fractionate isotopes?

The study has unequivocally demonstrated that siliceous sponges Spirastrella cuspidifera and Prostylyssa foetida from the same microecological niche exhibit a high degree of species specificity, while accumulating a host of heavy metal ions (Ni, Cr, Cd, Sn, Ti, Mo, Zr). S. cuspidifera accumulated, in addition, 60Co and 63Ni, showing discrimination against other radionuclides, 137Cs and 131I, present in the ambient waters receiving controlled low level waste discharges from a B.W.R. nuclear power station. P. foetida, on the other hand, accumulated only 131I and showed discrimination against other radionuclides including 60Co, although the stable iodine concentrations in both the sponges were the same. The specific activity of 60Co (in becquerels per gram of 59Co) in S. cuspidifera and 131I (in becquerels per gram of 127I) in P. foetida were at least two orders of magnitude greater than in the ambient sea water. That of 63Ni (in becquerels per gram of 62Ni) in S. cuspidifera, on the other hand, was lower by two orders of magnitude than in either abiotic matrices from the same environment. Thus, not only did both the species show bioaccumulation of a specific element, but also preferential uptake of isotopes of the same element, though they were equally available for intake. Such differential uptake of isotopes can possibly be explained in terms of two quite different mechanisms operating, each applicable in a particular case. One is that the xenobiotic isotope enters the environment in a physicochemical form or as a complex different from that of its natural counterpart. If equilibration with the latter is slow, so that the organism acquires the xenobiotic in an unfamiliar chemical context, it may treat it as a chemically distinct entity so that its concentration factor differs from that of stable isotope, thus changing the specific activity. Alternatively, if the xenobiotic is present in the same chemical form as the stable isotope, the only way in which specific activities can be modified is by fractionation on the basis of mass of isotope. In view of the remarkable concentration factors observed for stable and radioactive isotopes of the same element and the specific activities reached, it is desirable that species of sponges, especially from the coastal and estuarine environments, be monitored to detect levels of pollution due to anthropogenic substances.

Animals↗
PubMed1985

Sponge 'sentinel' of heavy metals.

The possibility of monitoring siliceous sponges as an ideal bioindicator of 17 trace metals and halogens was investigated. Of the two species of Demosponge from the Indian coastal waters receiving stable and radioactive nuclides (54Mn, 63Ni, 65Zn, 60Co, 75Se, 113Sn, 90Sr, 131I, 137Cs), Spirastrella cuspidifera was found to accumulate Cd, Cr, and Sn in the range of 15-2000 micrograms g-1 dry tissue, some 5-7 orders of magnitude higher than in the ambient waters. Prostylyssa foetida, from the same microecological niche, was found to be totally free of these three metal ions. The bioaccumulation of Ni was also significantly higher in S. cuspidifera (400-2250 micrograms g-1) than in P. foetida (7-15 micrograms g-1). The former species was also found to be an ideal sentinel for detecting levels of Co, Zn, and Ti; levels of Cu, Mn, Pb Fe and Sr were higher in P. foetida, but those of the halogens I and Br were practically identical in both species. Furthermore, bioaccumulation of metal ions was found to be a function of sponge tissue itself, rather than that of either obligate or facultative symbiont microflora. In view of the high degree of species specificity which sponges exhibit while accumulating many trace metal ions, a 'sponge watch programme' is proposed on a global scale for monitoring the health of coastal ecosystems against a variety of potentially toxic pollutants.

Animals↗
PubMed1984

Oxygen as a driving gas for nebulisers: safe or dangerous?

Changes in blood gas tensions occurring when 100% oxygen or air was used as the driving gas for nebulised salbutamol were studied in 23 patients with severe airways obstruction. The patients fell into three groups: nine had chronic bronchitis and emphysema with carbon dioxide retention, seven had emphysema and chronic bronchitis without carbon dioxide retention, and seven had severe asthma (no carbon dioxide retention). When oxygen was used as the driving gas patients who retained carbon dioxide showed a mean rise of 1.03 kPa (7.7 mm Hg) in their pressure of carbon dioxide (Pco2) after 15 minutes (p less than 0.001) but the Pco2 returned to baseline values within 20 minutes of stopping the nebuliser. The other two groups showed no rise in Pco2 with oxygen. When air was used as the driving gas none of the groups became significantly more hypoxic. Although it is safe to use oxygen as the driving gas for nebulisers in patients with obstructive airways disease with normal Pco2, caution should be exercised in those who already have carbon dioxide retention.

Adult↗
PubMed1984

Binding and uptake of [125I]iodoprolactin by epithelial cells of the rat choroid plexus: an in vivo autoradiographic analysis.

Light and electron microscopic (EM) autoradiography were used to determine the subcellular fate of [125I] iodo-PRL that specifically binds to epithelial cells of the rat choroid plexus. Experimental animals (total binding) received an external jugular vein injection of ovine [125I]iodo-PRL, whereas control animals (nonspecific binding) received an identical dose of [125I]iodo-PRL plus a 500-fold excess of unlabeled PRL. Experimental and control animals were killed by vascular perfusion 3, 20, 40, 60, and 240 min after hormone injection. Choroid plexuses were removed, processed to Epon, and prepared for light and EM autoradiography. Quantification of silver grains at the light microscopic level revealed an intense autoradiographic reaction over the epithelial cells of experimental animals 3, 20, 40, and 60 min after hormone injection. The co-injection of unlabeled PRL resulted in a statistically significant reduction in the autoradiographic reaction throughout the initial 60 min of the test period, reflecting specific binding of PRL during this interval. Analysis of EM autoradiographs revealed that the initial binding of [125I]iodo-PRL occurred primarily at the basal and lateral plasmalemma of the epithelial cells. With time there was a dramatic reduction in the amount of radiolabel localized to the cell membrane and a concomitant increase in silver grains localized over the interior of the cells. Internalized [125I]iodo-PRL exhibited a preferential localization to small cytoplasmic vesicles, short tubules, multivesicular bodies, and dense bodies. Combined acid phosphatase cytochemistry and EM autoradiography revealed that only 11.2% of the internalized silver grains were localized over acid phosphatase-positive structures 40 min after injection. The results indicate that subsequent to the initial binding of [125I]iodo-PRL to the cell membrane, internalization and translocation occurs primarily to nonlysosomal cytoplasmic organelles. The study also demonstrates at least a partial or ultimate entrance of internalized PRL to the lysosomal system.

Acid Phosphatase↗
PubMed1984

Smoking and malignant disease: a general practice study.

This study, involving a practice population of 7,200 patients, compared the smoking habits of patients suffering from malignant disease (excluding skin cancer) with the smoking habits of controls matched for age and sex. Patients with malignancies were found to smoke more heavily than their controls; this difference was particularly marked between the younger patients and their controls. Data on the most prevalent malignancies (carcinomata of the breast, cervix, rectum, colon and bladder) revealed that this tendency to heavier smoking was more marked in patients with neoplasia of cervix or bladder than in patients with breast or colorectal neoplasms. The age of these patients at diagnosis was reviewed in relation to smoking habits. Although the numbers were small, it appeared that patients who smoke present at an earlier age than non-smokers, except in cases of neoplasia of the cervix.These results seem to justify further general practice studies into the links between smoking and malignant disease.

Adult↗
PubMed1983

Characterization of lactogen binding sites in choroid plexus.

Prolactin binding sites have been demonstrated previously in rat choroid plexus using in vivo radioautography (Walsh et al. 1978). In the present study we have employed this procedure to characterize further the binding specificity of these sites. Following the injection of 125I-hGH or 125I-oPRL an intense radioautographic reaction was observed over the choroid plexus. The reaction was significantly reduced by coinjecting excess unlabeled hGH or oPRL but not bGH. The specific binding of 125I-oPRL to choroid plexus from rat, rabbit, sheep and pig was demonstrated by in vitro assays. Subsequently a survey of 125I-oPRL specific binding in a number of regions of pig brain indicated that the highest binding was in choroid plexus. A detailed study of the characteristics of 125I-oPRL binding to pig choroid plexus was undertaken. Specific binding increased with choroid plexus homogenate protein to a maximum of 30% (3.0 mg protein/tube). Binding was maximum at 4 degrees C by 30-40 h of incubation. During the incubation the integrity of 125I-oPRL in the incubation medium declined steadily to 50% after 20 h and 35-40% after 48 h. Radioactivity eluted from binding sites was fully intact as judged by rebinding to lactogen receptor-enriched membranes. Binding showed a broad pH optimum of 5.5-7.5. On cell fractionation of choroid plexus binding sites were enriched in microsomes. The binding of 125I-oPRL and 125I-hGH was inhibited in a dose-dependent manner by unlabeled lactogens and was of high affinity. hGH and oPRL were equipotent inhibitors of the binding of both radioligands whereas bGH and a variety of structurally unrelated peptides were non-inhibitory.

Animals↗