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Biomedical subjects

A Patel

Publications and source records attributed to A Patel.

At least 307 records · Page 17Linked to original sources

Hypogonadotropic patients with ultrasonographically detected polycystic ovaries: endocrine response to pulsatile gonadotropin-releasing hormone.

To characterize the endocrine response during induction of ovulation in patients with hypogonadotropic hypogonadism and ultrasound findings of polycystic ovary, we performed a retrospective analysis of 22 treatment cycles with pulsatile gonadotropin-releasing hormone (GnRH) in such patients and of 17 treatment cycles in similar patients with ultrasonographically normal ovaries. Of the 21 patients studies, 11 had an ultrasound finding of polycystic ovaries and ten had ovaries that appeared normal. Serum luteinizing hormone (LH), follicle-stimulating hormone (FSH) and estradiol levels, number of follicles of diameter > 12 mm (by ultrasound), and ovulation and conception rates were measured. Patients with hypogonadotropic hypogonadism and ultrasound-diagnosed polycystic ovary had pretreatment endocrine status similar to those with normal ovaries, but had much higher baseline ovarian volume. Ovulation induction with pulsatile GnRH induced much higher serum LH concentrations in the former group despite similar FSH levels. This difference preceded any change in estradiol levels. The former group consistently recruited significantly more follicles during pulsatile GnRH treatment. However, ovulation and conception rates were (non-significantly) higher in the latter group. In conclusion, this study characterized a subgroup of hypogonadotropic patients with ovarian morphology, volume and response to ovulation induction similar to in patients with polycystic ovary syndrome. When treated with pulsatile GnRH, those with polycystic ovary significantly hypersecreted LH before their estradiol level changed significantly. The primary lesion in polycystic ovary syndrome seems to be in the ovary, with pituitary hypersecretion of LH secondary to disturbed ovarian feedback signalling.

Estradiol↗

Issues of security and network security in Health Care Information Systems.

A Health Care Establishment (HCE) is an establishment where medical services are rendered. The above services are provided by the health care personnel. The infrastructure of a HCE may include Information Technology (IT) equipment that stores and processes HC information. Previously, IT equipment consisted solely of stand-alone systems, whereas in recent years, the trend has been towards computer networks and distributed systems in HCEs. The spread of distributed information technology in HCEs have necessitated the implementation of Security in HCISs, to assure confidentiality, integrity and availability of HCE information. This paper discusses the issues of Security and Network Security in Health Care Information Systems (HCISs). It also suggests a method in establishing Network Security Guidelines and describes Principles for the provision of Network Security in HCEs.

Computer Communication Networks↗

Long-term outcome after percutaneous treatment of transitional cell carcinoma of the renal pelvis.

PURPOSE: The application of conservative surgery has been established in the treatment of transitional cell tumors of the renal pelvis. We reviewed retrospectively the long-term outcome after percutaneous treatment of select patients referred to a tertiary center with transitional cell tumors of the renal pelvis. MATERIALS AND METHODS: We studied 28 patients referred with a presumptive diagnosis of transitional cell carcinoma of the renal pelvis based on filling defects noted on excretory urograms. At percutaneous endoscopy tumor was resected in 26 patients, while no tumor was found in 2. All 19 men and 7 women smoked, and mean age at presentation was 65 years. Of the patients 18 presented with hematuria and 6 had bilateral upper tract tumors. After percutaneous resection, the access tract was irradiated either with iridium wire in 12 patients or a commercial high dose rate radiation delivery system in 12. Thiotepa was instilled into the nephrostomy tube without brachytherapy in 1 patient and 1 received no adjuvant treatment in all. All patients were followed by excretory urography and urine cytology. Cystoscopy and retrograde pyelography were performed when technically possible. RESULTS: After percutaneous tumor resection 6 patients (23%) had local recurrence in the treated renal pelvis, including 3 at 44, 55 and 60 months, respectively. Further conservative treatment was initially possible in 4 of these patients but ultimately only 2 (both of whom had late recurrences) retained the treated kidney. Of the 11 patients with recurrence elsewhere in the urinary tract the bladder was invariably involved (11), while synchronous or metachronous ureteral recurrence was less common (3). Nine patients remained free of any urothelial recurrence in the upper or lower tract. No patient had recurrent tumor in the nephrostomy tract. Of the patients 7 suffered from procedure-related complications, including 1 who had a persistent urinary fistula that failed to heal after brachytherapy and required nephroureterectomy. There have been 6 deaths during followup, of which 2 were disease related. The 3-year estimated local recurrence-free survival rate was 86% (95% confidence interval 63 to 95%), cause-specific survival rate 91% (95% confidence interval 67 to 98%) and overall survival rate 78% (95% confidence interval 55 to 90%). Differences in recurrence-free survival, comparing those with recurrence in the treated renal pelvis or elsewhere in the urothelium and those remaining disease-free, did not translate to a significant overall survival difference (p < 0.5) between these groups. CONCLUSIONS: Our results suggest that the combination of percutaneous local resection and tract irradiation offers an effective long-term alternative to radical extirpation in the management of select patients with superficial transitional cell carcinoma confined to the renal pelvis. When the postoperative nephrostogram demonstrates a leaking renal pelvis, tract irradiation should not be given.

Aged↗

Factors influencing electrovaporization in the treatment of benign prostatic hyperplasia.

Electrovaporization refers to the process of vaporizing tissue using electrical energy. Proposed as a new treatment method for benign prostatic hyperplasia (BPH), this technique allows removal of prostatic tissue with simultaneous coagulation, thereby minimizing blood loss. The recent increase in popularity of electrovaporization in the treatment of BPH warrants a quantitative assessment of the process, including an objective evaluation of its influencing factors. In this study, the effects of power, mechanical loading, and excursion rate on tissue removal by electrovaporization were examined in fresh skeletal muscle. A monopolar electrode was attached to the weighted arm of a linear motion system and rolled across the tissue surface while activated by a radio-frequency generator. The tissue samples were frozen and cut longitudinally to allow visualization and measurement of the vaporized groove using an optical imaging technique. The volume of tissue removed increased significantly when power was increased from 120 to 150 W (46 to 119 mm3, p = 0.006), when the load was increased from 20 to 50 gm (20 to 119 mm3, p = 0.002), and when the excursion rate was decreased from 25 to 15 mm/s (29 to 69 mm3, p < 0.05) and from 15 to 10 mm/s (69 to 137 mm3, p < 0.05). There was no significant gain in volume removed when power was increased to 180 W or when the load was increased to 70 gm, indicating that these factors are constrained with regard to optimal tissue removal. Using a novel method to quantitatively assess tissue removal by electrovaporization, this study has demonstrated that greater tissue removal can be achieved by increasing power, increasing the load, or decreasing the excursion rate, but only within limits.

Animals↗

Evaluation of a soluble fibrin assay in patients with suspected pulmonary embolism.

In order to determine the clinical utility of an enzyme immunoassay (EIA) for soluble fibrin in patients with suspected pulmonary embolism (PE), 195 unselected patients with suspected PE underwent blood sampling for measurement of plasma levels of soluble fibrin, and objective testing for PE. A soluble fibrin result of < or = 0.75 micrograms/ml showed a sensitivity of 100% for PE and a specificity of 12.8%, whereas a soluble fibrin result of < or = 1.35 micrograms/ml showed a sensitivity of 90.3% and a specificity of 49.4% for PE. The soluble fibrin assay has potential clinical utility in excluding PE.

Adolescent↗

Molecular analysis of glomerular diseases in renal biopsies: initial results of a collaborative international study. The International Study Group for Molecular Study of Kidney Biopsies.

An accurate assessment of which patient with glomerular disease will progress to end-stage renal failure would be an important addition to establishing prognosis and evaluating therapeutic strategies. We previously found the development of glomerular scarring in animal models was preceded by an increase in glomerular type IV collagen mRNAs and that the level of scarring predicted the rate of progression. The purpose of this study was to determine whether these findings apply to human glomerular diseases using microdissected glomeruli and assessment of mRNA by competitive PCR. After showing that the levels of type IV collagen mRNAs were elevated in sclerotic glomeruli isolated from nephrectomies, we undertook this preliminary cross-sectional study of type IV collagen subchain mRNAs in renal biopsies in two of the leading causes of glomerulosclerosis, diabetic nephropathy, and membranous glomerulopathy. We found that glomerular type IV collagen mRNA levels were altered in disease-specific ways. The relative levels of the individual alpha-chains of type IV collagen depended on the anatomic site of the glomerular lesions. The alpha 2 type IV/alpha 3 type IV collagen mRNA ratio was high in diabetes mellitus, but not in membranous glomerulopathy. These data, coupled with those obtained from experimental animals, suggest that a dysregulation of basement collagen synthesis underlies progressive glomerular scarring. If these conclusions are verified in prospective studies it will be feasible to assess the risk of developing progressive glomerulosclerosis in the individual patient and to quantitatively assess therapeutic responses in a timely manner.

Aged↗

The relation of fibrous degeneration to menopausal status in small uterine leiomyomas with evidence for postmenopausal origin of seedling myomas.

It is well known that uterine leiomyomas shrink after the menopause. Fibrosis is the most common type of myomatous degeneration, but its relationship to menopause has not been studied. We evaluated fibrosis in 237 small myomas (< 1 cm) in relation to menopause, tumor size, intrauterine location, and patient age. Substantial fibrosis was seen in 33 (21%) of 159 small premenopausal myomas versus 39 (50%) of 78 small postmenopausal myomas (P < 0.001). This relationship was even stronger for women between 40 and 60 years of age: 27 (21%) of 126 premenopausal women versus 12 (71%) of 17 postmenopausal women (P < 0.001). Only 23 (23%) of 101 2- to 4-mm myomas had substantial fibrosis versus 45 (40%) of 112 5- to 9-mm myomas (P < 0.01). Small postmenopausal myomas that were inframucosal had less frequent fibrosis (3 [27%] of 11) than their intramural and subserosal counterparts (36 [54%] of 67) (P = 0.05). There was a significant increase in seedling myomas (fully cellular myomas < 1 cm) from postmenopausal women aged 60 to 70 years (13 [35%] of 37) compared with younger postmenopausal women (1 [6%] of 17) (P < 0.01). We conclude that fibrosis is strongly associated with menopausal status in small uterine myomas, that size and location are also related to fibrosis in small myomas, and that seedling myomas may arise after the menopause. Our interpretation of these findings is that the most likely cause of fibrosis in small myomas is senescence and that there may be heterogeneity in the molecular basis of senescence.

Adolescent↗

Current trends in molecular recognition and bioseparation.

Molecular recognition guides the selective interaction of macromolecules with each other in essentially all biological processes. Perhaps the most impactful use of biomolecular recognition in separation science has been in affinity chromatography. The results of the last 26 years, since Cuatrecases, Wilchek and Anfinsen first reported the purification of staphylococcal nuclease, have validated the power of biomolecular specificity for purification. This power has stimulated an explosion of solid-phase ligand designs and affinity chromatographic applications. An ongoing case in point is the purification of recombinant proteins, which has been aided by engineering the proteins to contain Affinity-Tag sequences, such as hexa-histidine for metal-chelate separation and epitope sequence for separation by an immobilized monoclonal antibody. Tag technology can be adapted for plate assays and other solid-phase techniques. The advance of affinity chromatography also has stimulated immobilized ligand-based methods to characterize macromolecular recognition, including both chromatographic and optical biosensor methods. And, new methods such as phage display and other diversity library approaches continue to emerge to identify new recognition molecules of potential use as affinity ligands. Overall, it is tantalizing to envision a continued evolution of new affinity technologies which use the selectivity built into biomolecular recognition as a vehicle for purification, analysis, screening and other applications in separation sciences.

Chromatography, Affinity↗

Direct injection for high sample throughput capillary gas chromatographic-mass spectrometric bioanalysis.

Because of the drawback of the relatively long analysis times inherent to temperature-programmed splitless injection capillary GC-MS, isothermal direct injection capillary GC-MS was investigated for quantitative bioanalysis. Using extracts from spiked plasma samples, we showed that high quality chromatography with a run time much shorter than that achievable with splitless injection can be achieved with direct injection. Sensitivity and other performance parameters were as good as or better than those of the splitless method. Since sample throughput is of great importance in laboratories that analyze thousands of biological samples, it is recommended that, when possible, splitless injection, which has traditionally been used in trace level GC-MS bioanalytical methods, be replaced by direct injection.

Bridged Bicyclo Compounds, Heterocyclic↗

A novel and rapid whole-blood assay for D-dimer in patients with clinically suspected deep vein thrombosis.

BACKGROUND: The clinical utility of using a novel whole blood assay for D-dimer (SimpliRED), alone or in combination with impedance plethysmography (IPG), was investigated in a two-center, prospective cohort study of 214 consecutive patients with clinically suspected deep vein thrombosis (DVT). METHODS AND RESULTS: All patients underwent the SimpliRED D-dimer assay, contrast venography, and IPG. According to the results of venography, 43 patients had proximal DVT (popliteal and/or more proximal veins), 10 had isolated calf DVT, and 161 had DVT ruled out. The D-dimer had a sensitivity of 93% for proximal DVT and of 70% for calf DVT, an overall specificity of 77%, and a negative predictive value of 98% for proximal DVT. The sensitivity and specificity of IPG for proximal DVT were 67% and 96%, respectively. When analyzed in combination with the IPG results, it was determined that (1) the combination of a negative D-dimer and a normal IPG had a negative predictive value of 97% for all DVT and of 99% for proximal DVT and occurred in 58% of patients (likelihood ratio, 0.1) and (2) the combination of a positive D-dimer and an abnormal IPG had a positive predictive value of 93% for any DVT and of 90% for proximal DVT and occurred in 14% of patients (likelihood ratio, 42.6). When the D-dimer and IPG results were discordant, it was not possible to exclude or diagnose DVT reliably; discordant results occurred in 28% of patients. CONCLUSIONS: The SimpliRED D-dimer assay, which can be performed and interpreted at the bedside within 5 minutes, has great potential in patients with clinically suspected DVT, especially for ruling out DVT, and is complementary to IPG. The assay should be evaluated in large clinical management studies.

Agglutination Tests↗

Mapping of the taurine transporter gene to mouse chromosome 6 and to the short arm of human chromosome 3.

Transport proteins have essential functions in the uptake of neurotransmitters and neuromodulators. We have mapped the gene encoding the taurine transporter, Taut, to the central region of mouse chromosome 6. Analysis of a cross segregating the neurological mutant mnd2 excluded Taut as a candidate gene for this closely linked mutation. To map the human taurine transporter gene, TAUT, a sequence-tagged site (STS) corresponding to the 3' untranslated region of the human cDNA was developed. TAUT was assigned to human chromosome 3 by typing this STS on a panel of somatic cell hybrids. Further analysis of a hybrid panel containing defined deletions of chromosome 3 suggested that TAUT maps to 3p21-p25. These data extend a conserved linkage group on mouse chromosome 6 and human chromosome 3p. Deletion of TAUT might contribute to some phenotypic features of the 3p- syndrome.

Animals↗

Expression of the herpes simplex virus type 2 latency-associated transcript enhances spontaneous reactivation of genital herpes in latently infected guinea pigs.

The latency-associated transcript (LAT) is the only herpes simplex virus (HSV) gene product detectable in latently infected humans and animals. In this report, we show that a 624-bp deletion in the promoter of the HSV-2 LAT had no discernable effect on viral growth in tissue culture or in acute genital infection of guinea pigs, but impaired LAT accumulation and led to a marked decrease in spontaneous genital recurrences when compared with the behavior of wild-type and rescuant strains. Differences in the ability of the mutant to replicate, or in how readily it established or maintained latency did not account for this finding. Thus, HSV LAT expression facilitates the spontaneous reactivation of latent virus.

Acute Disease↗

CD4+ T lymphocyte infiltration correlates with regression of a UV-induced squamous cell carcinoma.

It is currently unknown which arm of the immune system is responsible for regression of tumours. We have studied the T lymphocytes infiltrating a spontaneously regressing murine squamous cell carcinoma during the growth, plateau and regression phases of tumour development. In the plateau phase, where tumour growth is partially controlled by the immune system so that tumour size remains static, there was a considerable influx of CD4+ cells into the tumour. There was also an increase in the number of cells expressing the receptor for interleukin 2 (IL-2R), indicating that these cells were probably activated. The number of CD4+ cells remained high during the regression phase, where immunological destruction exceeded tumour growth. In contrast, CD8+ cells were only present in low numbers, and did not change during growth or regression of the tumours. These results indicate that CD4+ cells are probably responsible for tumour destruction. Thus CD4+ T lymphocytes are able to mediate tumour rejection and should be given more consideration for immunotherapy.

Animals↗

Transfection of a murine fibrosarcoma with intercellular adhesion molecule-1 enhances the response to adoptive immunotherapy.

BACKGROUND: Increasing the ability of antitumor effector cells to leave the vasculature and gain access to tumor cells may improve therapeutic efficacy. We undertook this study to determine whether increased expression of intercellular adhesion of molecular-1 (ICAM-1) by gene transfection would result in an improved response to adoptive immunotherapy in vivo. METHODS: C57BL/6 mice received 1 x 10(6) tumor cells on day 0. Tumor cells examined were MCA-105 (parental), NeoR (MCA-105 transfected with the neomycin resistance gene), or Clones 81 or 149 (MCA-105 cotransfected with NeoR and the gene for ICAM-1 and highly express ICAM-1). Animals were treated by use of no treatment, interleukin-2 alone (days 10 through 14), hyperthermia alone (days 10 and 13), or interleukin-2 + hyperthermia, and tumor growth was reported as a ratio to size on day 10. In vitro cytotoxicity was assayed by using murine lymphokine-activated killer cells. RESULTS: Tumors transfected with ICAM-1 and treated with hyperthermia + immunotherapy grew significantly (p < 0.05) slower (mean, 0.78 +/- 0.16 on day 19) than parental tumor (size, 1.35 +/- 0.22) or tumor cells transfected with NeoR alone (1.21 +/- 0.19). Tumors containing both MCA-105 and Clone 81 treated with hyperthermia + immunotherapy grew significantly slower (1.58 +/- 0.49 on day 19, p < 0.05) than untreated Clone 81 (2.38 +/- 0.46) or treated MCA-105 (2.49 +- 0.29) but more rapidly than treated Clone 81 (1.18 +/- 0.08), suggesting a paracrine efect for ICAM-1. CONCLUSIONS: These findings show that increased expression of ICAM-1 by tumor cells results in a significant increase in antitumor efficacy of combined interleukin-2 and hyperthermia in a murine model. Although the mechanism has yet to be elucidated, modulation of cellular adhesion may play a role in the therapeutic efficacy of cellular immunotherapy.

Animals↗

Nephrostomy track brachytherapy following percutaneous resection of transitional cell carcinoma of the renal pelvis.

Percutaneous nephrostomy can be used to resect transitional cell carcinoma (TCC) from the renal pelvis, to avoid nephrectomy in selected patients. This procedure carries a potential risk of tumour seeding along the nephrostomy track, which it is our policy to irradiate prophylactically. A total of 25 procedures on 23 patients have been carried out since 1982. The 18 males and five females had a median age of 64 years (range 46-81) at the time of treatment. Of the ten patients with only one functioning kidney, nine had undergone contralateral nephroureterectomy, seven for TCC, one for a non-functioning kidney, and one for renal tuberculosis; one patient had received radical radiotherapy for an inoperable contralateral renal tumour. The other 13 patients had asked for a conservative treatment approach to be adopted. From 1982-1989, low dose rate 192Ir wire was used in 13 patients to deliver a median dose of 45 Gy (range 40-50) to the full length of the track at the surface of nephrostomy tube. Since 1989, we have used a high dose rate (HDR) 192Ir microSelectron to treat 12 patients with a single fraction of 10-12 Gy, including two who had undergone previously 192Ir wire track irradiation of the same kidney. One patient required a nephroureterectomy after developing a non-healing renal pelvis leak following combined modality treatment. Otherwise, no early or late radiation-related morbidity has been seen, and no nephrostomy track recurrences have occurred during a median follow-up of 5 years (range 1-9). The HDR microSelection has enabled us to deliver this treatment quickly and simply during the standard postoperative stay in hospital following percutaneous nephrostomy.

Aged↗