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Biomedical subjects

B Patel

Publications and source records attributed to B Patel.

At least 37 records · Page 2Linked to original sources
PubMed2000

Patient self-injection: a new approach to administering luteinizing hormone-releasing hormone analogues.

OBJECTIVE: To investigate the feasibility and advantages of self-injection of a depot dose of luteinizing hormone-releasing hormone (LHRH) analogue in patients with prostate cancer. PATIENTS AND METHODS: Twenty patients (mean age 70.9 years, range 53-85) with locally advanced or metastatic prostate cancer were recruited from urology clinics and, using a defined protocol, were taught to perform self-injection of a depot LHRH analogue (Prostap SR or Prostap 3, leuprorelin acetate, Wyeth Laboratories, Berks, UK). Patients were then followed for 1 year. RESULTS: Of the 20 patients, 11 successfully learned to use self-injection and administered injections for the duration of the study. Ten of the patients chose self-injection and continued to self-inject after the end of this study. CONCLUSIONS: This pilot study of 20 patients showed that it is feasible for a selected group of patients to be taught self-injection of an LHRH analogue, and that some patients prefer this mode of drug administration.

Aged↗
PubMed2000

Effects of X chromosome number and parental origin on X-linked gene expression in preimplantation mouse embryos.

Diploid androgenetic mouse embryos, possessing two sets of paternally inherited chromosomes, and control fertilized embryos were used to examine the relative effects of X chromosome number and parental chromosome origin on androgenone viability and X-linked gene expression. A significant difference in efficiency of blastocyst formation was observed between XX and XY androgenones in some experiments, but this difference was not uniformly observed. Significant effects of both X chromosome number and parental origin on X-linked gene expression were observed. Male and female control embryos expressed the XIST: RNA initially. This expression was followed by a preferential reduction in XIST: RNA abundance in male embryos, indicating that dosage compensation for the X chromosome may normally require the downregulation of XIST: RNA expression in male embryos, in conjunction with the production of stable XIST: transcripts in female embryos. By the late blastocyst stage, XX control embryos expressed significantly more XIST: RNA than did XY embryos. Unlike their normal counterparts, XX androgenones did not express significantly more XIST: RNA than did XY androgenones at the late blastocyst stage. Androgenones exhibited severe repression of the Pgk1 gene, but during development to the late blastocyst stage Pgk1 mRNA expression increased in XX androgenones and decreased in XY androgenones. Thus, the initial repression of the Pgk1 gene in XX androgenones was lost as the XIST: RNA declined in abundance, and this loss was correlated with a failure of XX androgenones to express significantly more XIST: RNA than did XY androgenones. These results indicate that androgenones may lack a factor that is expressed from the maternal genome and required for dosage compensation in preimplantation embryos. The results also indicate that early dosage compensation in preimplantation embryos may normally be reversible, thus providing flexibility to meet different developmental requirements of the embryonic and extraembryonic lineages.

Animals↗
PubMed2000

The use of hypnosis in dentistry: a review.

Hypnosis is a valuable technique in patient management. With appropriate training, general dental practitioners can widen the treatment options they can offer to patients, especially those who are dentally anxious. This article provides a brief theoretical and historical overview, and a review of the literature pertaining to the clinical uses of hypnosis in dentistry.

Analgesia↗
PubMed2000

Superior mesenteric artery bypass for chronic mesenteric ischaemia: a DGH experience.

This article evaluates the results of single vessel bypass surgery for symptomatic chronic mesenteric ischaemia (CMI) in 6 patients undergoing a total of 8 superior mesenteric artery (SMA) bypass operations, all with good post-operative symptom relief. Post-prandial pain and weight loss was present in 5 out of 6 patients. Epigastric bruit was present in only two patients and 4 out of 6 patients had diarrhoea. The patients had varying degrees of peripheral vascular disease, ischaemic heart disease and hypertension. All patients had occlusion of the SMA on angiography and bypassing the occluded segment resulted in disappearance of the symptoms and weight gain. The vascular graft was sutured end to side to the front of the infra-renal aorta and end to side to the SMA, distal to the origin of the middle colic artery. Two patients had recurrence of symptoms due to graft occlusion at 3 and 4 years, respectively; they were successfully treated with repeat SMA bypass. There were no major complications or deaths related to the procedure in this study; one patient developed an incisional hernia requiring elective repair. Thus, early restoration of SMA circulation by bypass grafting in patients with CMI is sufficient to alleviate symptoms and prevent intestinal infarction with its high mortality rate.

Adult↗
PubMed1999

Virulence in Trypanosoma cruzi infection correlates with the expression of a distinct family of sialidase superfamily genes.

The overall success of Trypanosoma cruzi depends on its ability to invade the host and establish a long-term infection. Little is known of the genetic factors responsible for observed differences in virulence from strain to strain in T. cruzi. A virulent T. cruzi line was derived from an attenuated parental line by two passages through mice. To identify virulence genes a subtraction library was constructed and screened for cDNA expressed exclusively in the virulent line. One cDNA hybridized to 3.5 and 4.5 Kb RNA present in virulent trypomastigotes but absent in attenuated trypomastigotes. Sequence analysis showed the cDNA to encode an 85 kDa protein with homology to members of the sialidase/trans-sialidase superfamily and has been designated vp85.1. The highest amino acid sequence similarity was to a previously described T. cruzi sialidase-homologue pseudogene [Takle, G.B., O'Conner, J., Young, A.J. and Cross, G.A.M. (1992) Mol. Biochem. Parasitol. 56, 117-128]. The vp85.1 amino acid sequence has higher homology to members of the 160 kDa flagellar-associated antigen family, FL-160, than to other 85 kDa expressed sialidase superfamily members. Southern blot analysis of virulent and attenuated lines demonstrated a complex hybridization pattern consistent with a multiple gene copy family that was identical in both lines. Antibody directed against recombinant vp85.1 peptide recognized proteins between 95 and 115 kDa in total virulent parasite lysates which were absent in attenuated lysates. Peptide N-glycosidase F treatment reduced the high molecular weight bands to 85 kDa, indicating vp85 is an N-linked glycoprotein. Immunofluorescence with anti-vp85.1 demonstrated surface localization of vp85.1 on virulent, but not attenuated, trypomastigotes. We postulate this new subfamily of trans-sialidases may play a role in virulence.

Animals↗
PubMed1999

Absence of cardiac valve dysfunction in obese patients treated with sibutramine.

OBJECTIVE: Serotonin-releasing agents prescribed as weight-loss medications have been implicated as a cause of acquired aortic and mitral valve abnormalities. Sibutramine hydrochloride (MERIDIA) is a serotonin and norepinephrine reuptake inhibitor with proven efficacy of weight reduction. The purpose of this study was to determine the incidence of cardiac valve disease in sibutraminetreated patients. RESEARCH METHODS AND PROCEDURES: Obese patients with type 2 diabetes mellitus enrolled in an ongoing double-blind, placebo-controlled, parallel-arm, 12-month study of sibutramine (followed by a 12-month open label extension) underwent transthoracic echocardiographic imaging and color Doppler interrogation for assessment of cardiac valve anatomy and function. RESULTS: A total of 210 patients were evaluated. Of these, 133 were receiving sibutramine (72 in the double-blind period), and 77 were receiving placebo. The mean+/-Standard Deviation age was 54+/-9 years, and the mean duration of treatment was 229+/-117 days (approximately 7.6 months). The prevalence of left-sided cardiac valve dysfunction was low and similar for the two treatment groups (sibutramine 3/133, or 2.3%; placebo 2/77, or 2.6%). All five cases were cases of aortic insufficiency; four were mild, one was severe (in a placebo patient). All three sibutramine cases were patients over age 50; two had a history of systemic hypertension. CONCLUSION: The prevalence of left-sided cardiac valve dysfunction was not higher than background in obese patients treated with sibutramine for an average of 7.6 months.

Adult↗
PubMed1999

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) for treatment of prostate cancer: first results and review of the literature.

We present the involvement and association of TNF-related apoptosis-inducing ligand (TRAIL) with apoptosis. Its potential application as a therapeutic agent in urologic oncology is discussed. We have examined the sensitivity of prostate carcinoma cell lines DU145, PC3 and LNCaP to TRAIL-induced apoptosis and the expression of TRAIL receptors. Furthermore we looked into the sensitization of those prostate carcinoma cell lines to TRAIL-mediated apoptosis by low toxic levels of actinomycin-D. Furthermore, we review and discuss the pertinent literature on the molecular biology of TRAIL, its receptors and future potential for therapy in urologic oncology. Recent discovery and characterization of TRAIL has led to further broadening and insights into the apoptotic process. Based on preceding in-vitro studies, the first in-vivo study using TRAIL has been conducted and published in 1999. Systemic application of TRAIL in severe combined immune deficient (SCID) mice resulted in tumor regression of subcutaneous implanted mammary and colon cancer and several groups are looking into TRAIL sensitivity of prostate cancer and renal cancer cellines. Our in-vitro data revealed a significant increase of apoptotic cell death rate following the combined application of TRAIL with actinomycin-D. Our results suggest that the combination of TRAIL and ActD may be a therapeutic option in the treatment of drug/hormone refractory prostate carcinoma. In the future TRAIL may be used in combination therapy with other immunotherapies or gene therapies providing a synergistic effect or enhancing the efficacy of chemotherapeutic or radiotherapeutic regimens.

Journal Article↗
PubMed1999

Clinical presentation, radiographic findings, and diagnostic methods of pulmonary blastomycosis: a review of 100 consecutive cases.

BACKGROUND: We sought to determine the relationship among radiographic findings, clinical presentation, and diagnostic testing of pulmonary blastomycosis. METHODS: We reviewed the medical records of 100 consecutive patients with pulmonary blastomycosis. RESULTS: Air-space infiltrates were the usual radiographic finding of pulmonary blastomycosis. Mass-like infiltrates were associated more with chronic than acute presentations. Air-space and mass-like infiltrate were predominately involved in the upper lobes. Sputum analysis made the initial diagnosis of blastomycosis most often. Acute and chronic presentations were not different between immunosuppressed patients and the remainder of the patients. In addition, infiltrates on chest radiographs in immunosuppressed patients were similar to the other patients. CONCLUSIONS: In an endemic area, pulmonary blastomycosis should be considered for any pulmonary infiltrate, especially in the upper lobes. Sputum analysis in most cases aids in the diagnosis, but bronchoscopy and/or tissue biopsy should be considered if the suspicion of blastomycosis is high and sputum analysis is inconclusive, negative, or not possible. Follow-up with chest radiographs after antifungal therapy is reasonable until complete resolution or fibrotic changes in patients with pulmonary blastomycosis.

Acute Disease↗
PubMed1999

Warthin's tumor of the parotid salivary gland. A case report.

Neoplasms of the salivary glands are not uncommon. The dentist is in the unique position to make an early diagnosis and refer the patient for definitive treatment. This article will review the clinical appearance, pathology, treatment and potential complications of Warthin's tumor, a benign salivary gland tumor. It describes a case presented at the Salivary Gland Center. Columbia University School of Dental and Oral Surgery, New York Presbyterian Hospital-Columbia Campus.

Adenolymphoma↗
PubMed1998

Disruption of the talin gene compromises focal adhesion assembly in undifferentiated but not differentiated embryonic stem cells.

We have used gene disruption to isolate two talin (-/-) ES cell mutants that contain no intact talin. The undifferentiated cells (a) were unable to spread on gelatin or laminin and grew as rounded colonies, although they were able to spread on fibronectin (b) showed reduced adhesion to laminin, but not fibronectin (c) expressed much reduced levels of beta1 integrin, although levels of alpha5 and alphaV were wild-type (d) were less polarized with increased membrane protrusions compared with a vinculin (-/-) ES cell mutant (e) were unable to assemble vinculin or paxillin-containing focal adhesions or actin stress fibers on fibronectin, whereas vinculin (-/-) ES cells were able to assemble talin-containing focal adhesions. Both talin (-/-) ES cell mutants formed embryoid bodies, but differentiation was restricted to two morphologically distinct cell types. Interestingly, these differentiated talin (-/-) ES cells were able to spread and form focal adhesion-like structures containing vinculin and paxillin on fibronectin. Moreover, the levels of the beta1 integrin subunit were comparable to those in wild-type ES cells. We conclude that talin is essential for beta1 integrin expression and focal adhesion assembly in undifferentiated ES cells, but that a subset of differentiated cells are talin independent for both characteristics.

Actins↗
PubMed1998

The mitochondrial phosphoglyceroyl-ATP-containing polymer, purinogen, is unchanged by cardiac ischaemia and reperfusion but may function in the regulation of free intracellular inorganic phosphate concentrations.

Previous work in our laboratory demonstrating large unexplained systematic variations in the heart contents of free adenine nucleotides led us to propose the existence of some unrecognised sequestered form and thence to the purification of very labile acid-insoluble oligomers which we characterised as oligo[3-phospho-glyceroyl-gamma-triphospho(5')adenosine(3')] , abbreviated to (PG-ATP)n. More recently, we provided evidence that these oligomers appear to be the end chains of a complex polymer located in the mitochondrial intermembrane space of a number of rat tissues. We called this polymer purinogen and devised a means of assaying it quantitively [Patel, B., Sarcina, M. & Mowbray, J. (1994) Eur. J. Biochem. 220, 663-669]. Here we report measurements of purinogen in perfused hearts subjected to moderate and severe global ischaemia and reperfusion. Measurements of tissue and perfusate nucleotides, nucleosides and purine degradation products demonstrate that ischaemia led to the augmentation of the free nucleotide content by up to 30% and its re-sequestration on reperfusion in reversible but not in irreversible ischaemia. The purinogen content was unchanged by ischaemia or reperfusion implying the existence of some other unidentified storage pool. By contrast, glucose addition to glycolytically deprived hearts or removal of Pi from perfusion medium, conditions which might be expected to alter demand for intracellular Pi, led to the quantitative transfer of nucleotides between phosphate-rich purinogen and free nucleotides. The possibility that purinogen may act as a rapidly accessible reservoir of intracellular inorganic phosphate is discussed.

Adenosine Triphosphate↗
PubMed1998

Identification of spermatozoa and round spermatids in the ejaculates of men with spermatogenic failure.

OBJECTIVES: As many as 10% of infertile men have azoospermia caused by spermatogenic failure or ductal obstruction. The histologic diagnoses associated with spermatogenic failure--Sertoli cell-only syndrome, maturation arrest, and hypospermatogenesis--do not necessarily represent global changes in the affected testis, as occasional seminiferous tubules may still produce mature germ cells. Intracytoplasmic sperm injection (ICSI) allows individual sperm that have been isolated from testicular tissue to fertilize oocytes. This study assessed whether mature germ cells (either round spermatids or spermatozoa) were present in the ejaculates of patients with spermatogenic failure. METHODS: All semen analyses performed at our tertiary care institution from January 1993 through December 1995 were reviewed to identify azoospermic men with spermatogenic failure. During this period, our laboratory employed Nuclear-Fast Red and picroindigocarmine staining (NF-PICS) of cytospin slides to identify rare spermatozoa and spermatids in otherwise azoospermic ejaculates. RESULTS: Of 3005 analyses reviewed, 20 azoospermic men whose infertility was solely attributable to spermatogenic failure were identified. The histologic diagnoses were germinal cell aplasia (n = 7), complete maturation arrest (n = 6), incomplete maturation arrest (n = 3), and hypospermatogenesis (n = 4). Using the NF-PICS technique, mature germ cells were identified in the ejaculates of 15 men (75%), and 9 men (45%) had fully formed spermatozoa present. CONCLUSIONS: In the clinical management of azoospermic infertile men, the NF-PICS technique may be used to identify men who have some degree of testicular spermatogenesis. This might obviate the need for the purely diagnostic testis biopsy that is performed before therapeutic biopsy for testicular sperm extraction in conjunction with ICSI.

Biopsy↗
PubMed1998

Anal endosonography in patients with anorectal symptoms after haemorrhoidectomy.

BACKGROUND: Anorectal symptoms after haemorrhoidectomy are common and treatment is often empirical. Because of this, an audit was carried out of the value of anal endosonography in patients with anorectal symptoms after haemorrhoidectomy. METHODS: Between May 1993 and February 1997, 16 patients (ten men and six women of median age 56 (range 35-77) years) were investigated by anal endosonography for anorectal symptoms after haemorrhoidectomy which involved anorectal incontinence (n = 10), anal pain (n = 4) and obstructive defaecation (n = 2). The findings were compared with those in a matched group of asymptomatic patients after haemorroidectomy. RESULTS: Anal endosonography demonstrated an abnormality in 12 symptomatic patients. Of the ten patients with anorectal incontinence, endosonography showed an internal anal sphincter defect (n = 5), a combined sphincter defect (n = 2) and an isolated external anal sphincter defect (n = 1). Normal appearances were seen in all asymptomatic patients. The endosonographic abnormalities of the four patients with anal pain included internal anal sphincter defect (n = 1), extrinsic mass (n = 1), and intersphincteric abscess (n = 1). One of the two patients with obstructive defaecation had an isolated external anal sphincter defect on endosonography. CONCLUSION: These results show a high yield of endosonographic abnormalities in patients who experience symptoms after haemorrhoidectomy. In particular, occult sphincter injury as a cause of incontinence in these patients can frequently be demonstrated.

Adult↗
PubMed1998

New reference reagent for the quality assurance of anti-D antibody detection.

A UK BTS-NIBSC freeze-dried anti-D preparation has been prepared and used to monitor the performance of routine antibody detection tests and of the test operators. With the day-to-day use of this preparation, adverse changes in test performance and in test operator may be detected and appropriate action taken before the effect becomes significant. Two dilutions of this preparation have been defined, one which should be detected unequivocally in every test; the other, more dilute, may not be detected in every test but is used to monitor changes in performance. Experience with the use of this preparation is reported from three test centres undertaking routine antibody detection tests. By monitoring results over a series of working days, significant differences were noted in operator performance within one test centre, as was a reduced sensitivity of a given test system within one test centre compared with the same system in the other test centres. These differences were detected only by monitoring the results obtained with this preparation.

Coombs Test↗
PubMed1998

Characterization of an amorphous deposit in the lamina propria in oral snuff users in the Sudan as collagen.

Histological and ultrastructural features of 25 oral snuff dipper's lesions with distinctive subepithelial hyaline deposits were investigated. Periodic acid-Schiff reaction with and without diastase digestion demonstrated the presence of glycogen and other carbohydrates, but histochemical stains for normal collagen, elastin and fibrin showed a weak variable reactivity of the deposit. Although in 7/25 cases the deposit was in close proximity to labial salivary glands and on occasions ducts were found within the deposit, the presence of mucin was not a consistent feature. Congo red staining and immunohistochemical investigation with an anti-amyloid antibody did not support the previous contention that such deposits were amyloid in nature. Immunohistochemically, collagen antibodies also provided negative results, but ultrastructural features of three biopsies studied suggest that the bulk of this deposit is made up of collagen, as typical cross-striated fibrils were found. The pathogenesis of this deposit could therefore be interpreted as over-production and/or reduced turnover of collagen by resident fibroblasts, which is further altered by the ingredients of toombak. The deposit does not appear to be a secretory product.

Adult↗