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Biomedical subjects

S Patel

Publications and source records attributed to S Patel.

At least 721 records · Page 40Linked to original sources

Pheochromocytoma: operative strategy.

We studied 28 patients who had undergone 30 operations for pheochromocytoma since 1964. The tumor types included bilateral, extra-adrenal, malignant, recurrent, and multiple endocrine neoplasia, with 20 tumors confined to the adrenal gland. The preoperative studies used to localize the tumor included ultrasonography, intravenous urography, angiography, and computed tomography. Patients underwent exploratory operations via flank, subcostal, bilateral subcostal, midline, or thoracoabdominal approaches. In one case, that of a recurrence after bilateral adrenalectomy, surgical exploration discovered a tumor that had not been localized during the preoperative workup. Two patients underwent splenectomy because of injury incurred during operative exploration. Our experience suggests that preoperative localization is highly reliable, and therefore the benefits of extensive surgical exploration may be outweighed by its risks. We believe that with the exception of tumors that occur in association with childhood or pregnancy, multiple endocrine neoplastic syndromes, or recurrent disease, a direct approach to the tumor, possibly via the flank, is justified. Our results suggest that exploration of the contralateral adrenal or periaortic area is not so important as to be worth jeopardizing the spleen or other organs by a complex or extensive dissection.

Adolescent↗

Localisation of histamine-immunoreactivity in specific neurones of the gastropod CNS including a cell which has been identified as histaminergic.

Immunohistochemical procedures revealed the occurrence of histamine-like immunoreactivity in specific neurones in the gastropod nervous system. Positive staining was also associated with a characterised neurone known from previous biochemical studies to contain histamine. The proof of the restriction of histamine to specific neurones and the availability of a suitable antiserum to localise the amine makes it possible to examine the role of the compound in different nervous systems.

Animals↗

Dopaminergic neurones in various retinas and the postnatal development of tyrosine-hydroxylase immunoreactivity in the rabbit retina.

The localisation of tyrosine-hydroxylase immunoreactive neurones in retinas of a variety of animals were examined. Immunoreactivity was associated with specific populations of amacrine neurones in all species examined, viz; rabbit, guinea pig, monkey, cow, frog, pigeon and goldfish. Only in the goldfish was immunoreactivity also associated with processes situated in the outer plexiform layer showing that in this species catecholamine interplexiform cells exist. The development of tyrosine-hydroxylase immunoreactive neurones in the rabbit retina was also analysed. The first immunoreactive positive cells were observed by the third postnatal day. The immunoreactive positive neurones at this stage are weak and lack processes. The intensity of the immunoreactivity increases with development, but processes are lacking, until the 10th postnatal day. The immunoreactive neurones only appear fully developed by the 22nd to 28th postnatal day. Autoradiographical analysis of 3H-dopamine uptake strongly suggests that neurones containing tyrosine-hydroxylase immunoreactivity in the different retinas have the capacity to take up exogenous dopamine. It is therefore concluded that localisation of either 3H-dopamine uptake or tyrosine-hydroxylase provides a means of locating catecholamine neurones.

Animals↗

Postnatal development of serotonin-accumulating neurones in the rabbit retina and an immunohistochemical analysis of the uptake and release of serotonin.

The serotonin-accumulating neurones in the rabbit and bovine retina were studied with the use of immunohistochemistry to localize serotonin. It was established that a subpopulation of amacrine cells in both tissues has the ability to take up and store serotonin. The uptake process is very specific; known serotonergic uptake blockers, viz. chlorimipramine and Lilly 110140, abolish transport, while benztropine, a dopamine-uptake blocker, is ineffectual. The serotonin accumulated by the serotonergic neurones can be released by potassium depolarization in a calcium-dependent manner. All these results form a strong case for serotonin being a likely transmitter in the mammalian retina. The subpopulation of serotonin-accumulating neurones in the rabbit retina appears to be determined prenatally, as they can be observed immediately after birth. On the basis of the serotonin content in retinas from animals of different ages, it is suggested that the serotonin-accumulating cells mature around the 24th postnatal day. The same maturation period has been proposed for the rabbit retinal dopamine cells (Lam et al., 1981).

Animals↗

Aggressive choroid plexus papilloma.

A young woman, who was initially treated for an Arnold-Chiari malformation, was found 7 years later to have a posterior third ventricular tumor. A superior cerebellar approach allowed total resection of the mass, which was an aggressive choroid plexus papilloma. The patient was treated with whole cerebrospinal axis radiation. There is no clinical or computed tomographic evidence of recurrence after 4 years. The literature is reviewed and a discussion of aggressive choroid plexus papilloma (carcinoma) is presented.

Adult↗

Polyclonal orbital and systemic infiltrates.

Two unusual cases of benign lymphoproliferative disease associated with orbital and systemic involvement are described. Both have occurred in adults with longstanding histories and clinical manifestations that have mimicked lymphomas. The orbital disease has been both antecedent and subsequent to the systemic lesions. These cases emphasize the spectrum of lymphoproliferative disorders and call attention to the possibility of multisystem disease in patients with benign lymphoproliferative lesions.

Aged↗

Effects of intraaortic balloon counterpulsation on myocardial blood flow in patients with severe coronary artery disease.

The purpose of this study was to test the hypothesis that myocardial blood flow distal to a critical stenosis would increase during intraaortic balloon counterpulsation. Accordingly, 13 patients with severe coronary artery disease were studied at the time of elective preoperative insertion of an intraaortic balloon catheter. Hemodynamic measurements and measurements of myocardial blood flow were made before and during counterpulsation. Myocardial blood flow was measured with a xenon-133 washout technique. Compared with control measurements, the heart rate decreased from 87.8 +/- 18.8 to 82.8 +/- 13.4 beats/min (p = 0.02) and systolic arterial pressure decreased from 112.1 +/- 17.9 to 97.8 +/- 14.8 mm Hg (p = 0.004) during counterpulsation. Diastolic arterial pressure increased from 72.2 +/- 10.1 to 120.2 +/- 21.4 mm Hg (p = 0.00002) during counterpulsation. Myocardial blood flow for the entire group decreased from 48.8 +/- 14.1 to 42.6 +/- 11.0 ml/100 g per min (p = 0.008). Regional flows in the left anterior descending and circumflex distributions also decreased. Left anterior descending artery blood flow decreased insignificantly from 51.5 +/- 14.4 to 47.4 +/- 11.7 ml/100 g per min (p = not significant), while circumflex flow decreased from 50.7 +/- 12.2 to 41.1 +/- 8.9 ml/100 g per min (p = 0.008). When normalized for the rate-pressure product, myocardial blood flow was 53 +/- 16 X 10(-4) at rest and 55 +/- 12 X 10(-4) (p = not significant) during counterpulsation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Variability of peak flow in wheezy children.

A study of peak flow variability was carried out among a population sample of 63 wheezy children aged 9-11 years. Recordings were made over 12 days at three times during the day--first thing in the morning, on returning home from school and at bedtime. Eighty nine per cent of the children had symptoms during the diary period. The mean amplitude (difference between the highest and lowest daily peak flow values) was 17% of the mean daily value (range 4-48%). By cosinor analysis the amplitude was 12% of the mean value (range 1-53%). In 65% of the children the lowest point of the daily rhythm as determined by cosinor analysis lay between midnight and 8am; the rhythm was, however, statistically significant in only fourteen individuals (22%). These levels of variability are considerably lower than those previously reported in hospital based studies of adult asthmatics. As a method of demonstrating variable airflow obstruction, which is the defining physiological characteristic of asthma, the use of a peak flow diary alone appears to be of limited value in children.

Asthma↗

Respiratory morbidity and lung function after whooping-cough.

360 primary-school children with a history of whooping-cough were shown to have experienced an excess of other chest illnesses compared with 711 controls. This susceptibility may, however, have antedated the whooping-cough. Current respiratory symptoms were also more common in children who had had whooping-cough, though no differences were found on physical examination. No differences were found in lung function between cases and controls. Whooping-cough, as experienced by British children in recent years, is unlikely to cause subsequent respiratory morbidity and does not result in impaired lung function in later childhood.

Adolescent↗

Carcinoma of the breast and meningioma. Association and management.

An association between carcinoma of the breast and meningioma has been recognized recently. Three more cases are added to the few previously reported in the literature. An awareness of this association together with modern techniques of investigation, particularly CAT scanning, may permit earlier diagnosis and treatment of more cases. Meningioma as well as carcinoma of the breast is more common in women and the incidence of both tumors reaches a peak in the fifth and sixth decades. Both are related to pregnancy and have an estrogen-receptor protein. Lesions of the central nervous system following the diagnosis and treatment of breast cancer are usually presumed to be metastatic. Therefore, these lesions may be irradiated without complete clinical investigation. If the clinician is aware of this association, appropriate diagnostic procedures could lead to the surgical removal of a benign meningioma. Skull x-rays, bone scan, brain scan, CAT scan, and cerebral angiograms are useful in making a diagnosis. Besides surgery, radiation therapy and hormonal therapy may play a role in the management.

Aged↗

Effects of 12-O-tetradecanylphorbol 13-acetate (TPA) on a clonal human teratoma-derived embryonal carcinoma cell line.

The response of a human embryonal carcinoma cell line LICR LON HT39/7 to 12-O-tetradecanylphorbol 13-acetate (TPA) has been studied. Cells treated with 5 ng/ml of TPA undergo marked morphological changes, becoming flattened with nuclear enlargement and developing a grainy and often vacuolated cytoplasm. Parallel changes in the cell surface phenotype of the treated cells also occur. These include the appearance of membrane fibronectin, the embryonic antigen SSEA-1, and a glycoprotein antigen recognised by a monoclonal antibody. There is also increased expression of histocompatibility antigens. Other membrane molecules, such as peanut agglutinin receptor(s) and a 200 000 membrane glycoprotein appear to be removed from the membrane following TPA treatment. The high levels of alkaline phosphatase normally present in LICR LON HT39/7 are also reduced by TPA. Changes in the ultrastructure of the cells have also been observed, such as increases in nuclear complexity and in the number of intermediate filaments in the treated cells. This latter observation has been confirmed by immunofluorescent staining of the cells for prekeratins, which show an extensive network following the addition of TPA, but not before. 2-Dimensional gel electrophoresis of the proteins synthesized by LICR LON HT39/7 before and after addition of TPA has shown that there are a number of alterations in the proteins synthesised by the treated cells. Furthermore, immunoprecipitation of the culture supernatants from these cells has shown that TPA induces the synthesis and secretion of fibronectin. The alterations in the phenotype of LICR LON HT39/7 induced by TPA are irreversible and the altered cells, whilst they stop dividing, can be maintained for at least three weeks in culture. The analogue of TPA 12-O-tetradecanylphorbol 13-myristate does not produce the effects described above.

Antigens, Surface↗

Measurement of enterolactone and enterodiol, the first mammalian lignans, using stable isotope dilution and gas chromatography mass spectrometry.

Methods are described to extract and measure 2,3-bis(3-hydroxybenzyl)-gamma-butyrolactone (enterolactone) and 2,3-bis(3-hydroxybenzyl)butane-1,4-diol (enterodiol) from physiological fluids. They are based on the use of stable labelled analogues of each compound as internal standards with end point assay being by gas chromatography mass spectrometry. The methods were developed to quantify enterolactone and enterodiol in experiments designed to investigate the significance and source of these compounds in man and animals. Examples of studies on human ovarian blood and investigations of their excretion in urine following dietary manipulation are described.

4-Butyrolactone↗

Hypothalamic-pituitary-adrenal (HPA) axis function in patients receiving long-term intra-articular corticosteroids.

The hypothalamic-pituitary-adrenal (HPA) axis function of eight patients with rheumatoid arthritis receiving regular intra-articular methyl prednisolone acetate was studied. Tests of the HPA axis 5-7 weeks after the last injection revealed suppression in two patients. Some patients receiving intra-articular corticosteroids may therefore have abnormal responses to stress.

Aged↗

High-dose computed tomography in the evaluation of low attenuation lesions in the neck.

Recent reports have established the clinical utility of computed tomography (CT) in the evaluation of jugular vein thrombosis. Other abnormalities of the soft tissues in the neck can mimic this condition. This study reviews the pertinent normal soft tissue and vascular anatomy of the neck and describes the use of high-dose CT in the evaluation of low attenuation lesions in this area. Various abnormalities are compared and contrasted, including cystic hygroma, neoplasm, abscess, and venous thrombosis.

Abscess↗