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Biomedical subjects

S Sheth

Publications and source records attributed to S Sheth.

At least 37 records · Page 2Linked to original sources
PubMed1999

US guidance for thoracic biopsy: a valuable alternative to CT.

PURPOSE: To determine the role, accuracy, and selection criteria of ultrasonographic (US) guidance for biopsy for thoracic lesions. MATERIALS AND METHODS: Imaging-guided thoracic biopsies (n = 86) were performed in 84 consecutive patients. US guidance was used for lesions abutting the chest wall; computed tomographic (CT) guidance was used for all masses surrounded by aerated lung. Mass location and size, guidance modality, histologic results, procedure time, and complications were recorded. RESULTS: Thirty-four lesions (19 parenchymal, six pleural, six chest wall, three mediastinal) were amenable to US-guided biopsy. The mean mass diameter was 4.3 cm, the mean number of passes was 3.2, and the mean procedure time was 31.4 minutes. A histologic diagnosis was achieved in 31 (91%) patients, including all with small (< 2-cm) masses (n = 9). There was one case of pneumothorax. CT guidance was used in 52 (60%) of 86 cases. Lesions were parenchymal (n = 41), pleural (n = 1), and mediastinal and hilar (n = 10). The mean diameter was 2.9 cm, the mean number of passes was 2.3, and the mean procedure time was 45.2 minutes. A histologic diagnosis was achieved in 37 (71%) patients, including 18 of 27 with a small mass. Complications included pneumothorax (n = 21) and parenchymal hemorrhage (n = 2). CONCLUSION: US is an effective and safe alternative to CT for guidance at biopsy of masses abutting the chest wall. Real-time US visualization allows accurate needle placement, shorter procedure time, and performance in debilitated and less cooperative patients.

Adolescent↗
PubMed1999

Diagnosis and staging of ovarian cancer: comparative values of Doppler and conventional US, CT, and MR imaging correlated with surgery and histopathologic analysis--report of the Radiology Diagnostic Oncology Group.

PURPOSE: To determine the optimal imaging modality for diagnosis and staging of ovarian cancer. MATERIALS AND METHODS: Two hundred eighty women suspected to have ovarian cancer were enrolled in a prospective study before surgery. Doppler ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging were used to evaluate the mass; conventional US, CT, and MR imaging were used to stage spread. RESULTS: All three modalities had high accuracy (0.91) for the overall diagnosis of malignancy. In the ovaries, the accuracy of MR imaging (0.91) was higher than that of CT and significantly higher than that of Doppler US (0.78). In the extraovarian pelvis and in the abdomen, conventional US, CT, and MR imaging had similar accuracies (0.87-0.95). In differentiation of disease confined to the pelvis from abdominal spread, the specificity of conventional US (96%) was higher than that of CT and significantly higher than that of MR imaging (88%), whereas the sensitivities of MR imaging (98%) and CT (92%) were significantly higher than that of conventional US (75%). CONCLUSION: MR imaging is superior to Doppler US and CT in diagnosis of malignant ovarian masses. There is little variation among conventional US, CT, and MR imaging as regards staging.

Adult↗
PubMed1999

Three-dimensional US of the prostate: early experience.

PURPOSE: To assess the feasibility of using a three-dimensional (3D) endorectal transducer at ultrasonography (US) in the prostate gland in a clinical setting. MATERIALS AND METHODS: Sixteen patients underwent 3D imaging of the prostate gland with a 3D endorectal probe following conventional two-dimensional (2D) US and prior to prostatic biopsy. Image acquisition was performed as a volume of data with nearly immediate reconstruction and simultaneous display of sectional anatomy in three orthogonal planes--sagittal plane, transverse or coronal plane, or any arbitrary oblique plane. Images were evaluated for presence of focal lesions, glandular volume, visualization of lateral and anterior portions of the gland, and extraglandular extension of tumor. RESULTS: Three-dimensional US allowed better visualization of the gland and focal lesions, especially on the coronally reconstructed images, which were judged superior to the sagittally or transversely reconstructed images for interpretation in 50% of the patients. Prostatic volumes obtained from 3D US were consistently smaller than volumes obtained from 2D US (20% difference, P = .006). Three-dimensional US was superior to 2D US in depicting tumor presence (nine of 10 right hemispheres, three of eight left hemispheres) and extraglandular extent of disease (three of five hemispheres). CONCLUSION: Three-dimensional endorectal prostatic US appears to be clinically feasible and easy to perform. Added anatomic information from the coronal plane may allow better depiction of tumors and extraglandular spread than is possible with current 2D techniques.

Endosonography↗
PubMed1999

Grafted poly(ethylene oxide) brushes as nonfouling surface coatings.

The identification of design criteria for the prevention of surface fouling by protein adsorption has been an elusive research goal. The current ideas in this domain assume two different directions. One focuses on correlating protein adsorption with macroscopic surface properties such as the water wettability. The second approach involves tailoring the molecular interactions between the adsorbing proteins and the surface. In this paper, we focus on the experimental results and theoretical ideas concerned with tuning the interfacial forces by means of terminally grafted PEO chains.

Adsorption↗
PubMed1999

Reproductive and sexual health and safe motherhood in the developing world.

The aim of this paper is to discuss the main hurdles and possible solutions concerning reproductive and sexual health and safe motherhood in the developing countries. In response to the changing global situation, a broader new concept of reproductive health has emerged. The Programme of Action of The International Conference on Population and Development (ICPD) emphasizes and highlights various aspects of reproductive health. No population in the world has met the goals of the ICPD. The problems are particularly acute in developing countries: between 20 and 40% of births are unwanted or wrongly timed, posing hardships for families and jeopardizing the health of a million women and children. An estimated 50 million induced abortions are performed each year, with some 20 million of these performed under unsafe conditions or by untrained providers. Almost 600,000 women die every year due to pregnancy-related causes, 99% of them in developing countries. Approximately 7.6 million infant deaths occur during the perinatal period each year. There are more than 333 million new cases of curable sexually transmitted diseases world-wide each year. Nearly 22 million people are estimated to be infected with the human immunodeficiency virus, of whom 14 million are in sub-Saharan Africa, with rapidly increasing numbers of infected persons in South and South-East Asia. When compared to the developed world, these figures are staggering because of barriers operating at different levels and preventing women from receiving care that is timely and of good quality. United efforts of obstetricians, pediatricians, sociologists, and different governmental and non-governmental organizations are required to achieve our targets.

Adolescent↗
PubMed1999

Risperidone use at a state hospital: a clinical audit 2 years after the first wave of risperidone prescriptions.

BACKGROUND: In spite of some inherent limitations, naturalistic data can provide information on populations that have greater heterogeneity than can controlled clinical trials and on functional outcomes that may be especially important in clinical practice. In the present retrospective naturalistic study, we evaluated key clinical outcomes among the first wave of risperidone-treated patients at a state psychiatric hospital. METHOD: Outcome data were extracted from the charts of 142 patients 2 years after initiation of treatment with risperidone. Their diagnoses included DSM-III-R schizophrenia (57%), schizoaffective disorder (22%), dementia and other organic conditions (7%), bipolar disorder (5%), and other psychiatric disorders (9%). RESULTS: During the 2-year period, 92 of 142 patients were discharged from the hospital: 61 (43%) were discharged on risperidone treatment and 31 (22%) were discharged on treatment with other drugs. At the time of the study, 50 of 142 patients were still in the hospital: of these, 18 (13%) were still receiving risperidone. The modal maximum daily dose of risperidone was 4.1 mg in patients discharged on risperidone treatment and 7.5 mg in patients still in the hospital. All groups were granted more ward privileges after starting risperidone, the most being granted to patients discharged from the hospital on risperidone treatment (p<.05 versus patients discharged on treatment with other drugs) and those still receiving risperidone in the hospital. Significantly fewer patients discharged on risperidone treatment than on treatment with other drugs were readmitted to the hospital within 2 years after discharge (p<.01). CONCLUSION: Improved privilege levels and a reduced readmission rate indicate that risperidone was an effective antipsychotic agent among a heterogeneous patient population in a state hospital. These factors may be especially important to justify use of this agent in the current fiscal climate.

Adult↗
PubMed1998

Inherited thrombophilic states.

Thrombophilic states are a group of conditions associated with increased predisposition to thromboembolic events. The well-recognized inherited thrombophilic states include resistance to activated protein C (APC) (Factor V Leiden) and deficiencies of plasma antithrombin, protein C, and protein S. These entities are aberrations in the natural anticoagulant systems that exist in plasma and at the endothelial cell level. Other causes of inherited thrombophilia include hyperhomocysteinemia, abnormalities in the proteins of the fibrinolytic system, dysfibrinogenemias, deficiency of heparin cofactor II, abnormal thrombomodulin, and the recently described variation in the prothrombin gene. Most of the inherited abnormalities recognized to date are associated with venous thromboembolism (VTE) rather than arterial thrombosis. Approximately half of VTE episodes in patients with inherited thrombophilias occur in relation to events that are generally recognized as predisposing states, such as surgery, pregnancy, and immobilization. In this review, the risks of VTE associated with inherited risk factors are discussed, and guidelines for the diagnosis and management are presented.

Activated Protein C Resistance↗
PubMed1997

Pulmonary embolism developing in patients with sickle cell disease on hypertransfusion and IV deferoxamine chelation therapy.

Pulmonary disease, including thromboembolic problems, accounts for a large portion of the morbidity of sickle cell disease. Chronic transfusion therapy is now a part of long-term treatment of sickle cell patients with stroke and chest syndrome. The resultant iron overload must be treated with chelation therapy using deferoxamine. Poor compliance with subcutaneous chelation therapy has necessitated intravenous deferoxamine treatment. We describe two patients with sickle cell disease on such a regimen, who became hypoxic as a result of pulmonary thromboembolism, secondary to venous thrombophlebitis. The thrombophlebitis and subsequent pulmonary embolism probably reflect the hypercoagulable state seen in sickle cell and are not due to the deferoxamine therapy.

Adolescent↗
PubMed1997

Inherited hypercoagulable states.

Hypercoagulable states are a group of conditions associated with increased predisposition to thromboembolic events. Most of the inherited abnormalities recognized to date are associated with venous thromboembolism (VTE) rather than arterial thrombosis. The well-recognized inherited hypercoagulable states are the deficiencies of antithrombin, protein C and protein S, and the resistance to APC (factor V Leiden). These entities represent aberrations in the natural anticoagulant systems that exist in plasma. Other causes of inherited thrombophilia include abnormalities in the proteins of the fibrinolytic system, dysfibrinogenemias, deficiency of heparin cofactor II, abnormal thrombomodulin, elevated levels of histidine-rich glycoprotein, and the recently described variation in the prothrombin gene. One entity that has become firmly established as a predisposing factor for recurrent VTE is hyperhomocysteinemia. About half of VTE episodes in patients with inherited thrombophilias occur in relation to events that are generally recognized as predisposing states, such as surgery, pregnancy (particularly puerperium) and immobilization. In this review, the risks of VTE associated with inherited risk factors are discussed, and guidelines for the diagnosis and management are presented.

Antithrombin III Deficiency↗
PubMed1996

Subacute thrombosis and vascular injury resulting from slotted-tube nitinol and stainless steel stents in a rabbit carotid artery model.

BACKGROUND: Our objectives were to quantify the thrombogenicity and extent of vascular injury created by slotted-tube geometry stainless steel and nitinol coronary stents in a rabbit carotid artery model. METHODS AND RESULTS: Stents were implanted in rabbit right carotid arteries without antiplatelet therapy. Stainless steel stents were implanted for 4 days while nitinol stents were placed for 4 and 14 days (n = 8, 8, and 6, respectively). Stent thrombosis was assessed by thrombus weight, grading thrombus encroachment of the lumen, and by blood flow in the stented and contralateral arteries. Stainless steel stents at 4 days contained more thrombus than 4- and 14-day nitinol stents (20.0 +/- 5.9 versus 2.5 +/- 0.6 and 2.7 +/- 0.3 mg, respectively; P < .000001). Stainless steel stents were more often occluded by thrombus (6 of 8) or contained more subocclusive thrombus (2 of 8) than nitinol stents (0 of 14, P < .002). Resting blood flow was reduced in arteries with stainless steel stents compared with 4- and 14-day nitinol stents (1.5 +/- 2.8 versus 24.0 +/- 2.0 and 25.5 +/- 1.9 mL/min, respectively, P < .000001). Stainless steel stents were less uniformly expanded, had deeper strut penetration into the vascular wall, and were associated with more extensive medial smooth muscle cell necrosis. There were strong correlations (r = .77 to .95) between variables of thrombosis extent (thrombus weight and grade) and histologically determined vascular injury (strut penetration and medial necrosis). CONCLUSIONS: Slotted-tube stainless steel stents were more thrombogenic and created more extensive vascular injury than nitinol stents in a rabbit carotid artery model. The mechanisms underlying these differences probably are related to metallurgic and design geometry properties of the two stent types.

Acute Disease↗
PubMed1996

Efficacy of cold-steel uvulopalatoplasty.

Seven patients underwent cold-steel uvulopalatoplasty with tissue removal similar to that being performed with laser-assisted uvulopalatoplasty. The severity and length of postoperative pain, days out of work, postoperative complications, and efficacy in reducing snoring were assessed. The minimum follow-up period was 6 months. The average length of postoperative pain (inability to eat a completely normal diet) was 6 days. All but one patient underwent only one session of cold-steel uvulopalatoplasty with satisfactory relief of snoring. The remaining patient required two sessions. One patient had some mild postoperative bleeding, which resolved with silver nitrate. Improvement in snoring goes as follows: marked improvement in three patients, moderate improvement in three patients, and slight improvement in one patient. None of the patients had complete resolution or the same degree of snoring. Patients who underwent concomitant oropharyngeal procedures (i.e., tonsillectomy) in addition to cold-steel uvulopalatoplasty tended to have pain for a longer period of time and required a longer convalescence period. Cold-steel uvulopalatoplasty is an inexpensive and viable option to outpatient laser-assisted uvulopalatoplasty for the reduction of snoring in select patients.

Adult↗
PubMed1995

Haplotypes of the human beta-like globin gene cluster: analyzing the 3' Hpa I polymorphic site by long distance PCR.

Haplotypes of the beta-like globin gene cluster in individuals with sickle cell disease appear to be important as prognostic factors for the severity of the disease. The Hpa I polymorphic site 3' of the beta-globin gene is very often involved in haplotyping. However, this restriction site cannot be ascertained by conventional PCR, as it is in the middle of a long repetitive sequence. Long distance PCR was employed to amplify this Hpa I-containing region. By positioning either one or both primers outside the repetitive sequence, specific amplification was achieved. Moreover, sufficient amplification can be obtained by using a white cell lysate instead of purified DNA, thereby significantly reducing the amount of blood needed, and the total procedure time.

Anemia, Sickle Cell↗
PubMed1995

Kinetics of drug delivery to the arterial wall via polyurethane-coated removable nitinol stent: comparative study of two drugs.

Polymer-coated removable stents were used to deliver 14C-labeled etretinate and 3H-labeled forskolin to the vessel wall in 31 New Zealand White rabbits to study their kinetics. Stents loaded with etretinate (n = 8) and forskolin (n = 14) were implanted in the rabbit carotid arteries, and the animals were euthanized at different time intervals. Drug levels were measured in the media and adventitia of the stented segment, in distant tissues, and in blood. In four rabbits, forskolin-loaded stents were percutaneously retrieved 2 hr after implantation in the carotid artery, and the tissue and blood levels were determined 2 and 24 hr after retrieval. In seven rabbits etretinate-loaded stents were retrieved 72 hr after implantation in abdominal aorta, and drug levels were measured in the tissues and blood immediately after and at 1 and 4 days after retrieval. Levels of etretinate in the vessel wall peaked at 24 hr (250 ng/mg) and remained high up to 72 hr (185 ng/mg) after stent placement. Levels of forskolin peaked within 2 hr of stent placement (135 ng/mg) and rapidly declined to 4.9 ng/mg at 24 hr with the stent in situ. About 50% (1.4 mg) of the original etretinate remained in the stent at 72 hr compared to about 5% (0.08 mg) of forskolin at 24 hr. Ratio of peak drug levels in the vessel wall to those in the blood was 6,000 for etretinate and 780 for forskolin. (ABSTRACT TRUNCATED AT 250 WORDS)

Alloys↗
PubMed1995

Endometrial blood flow analysis in postmenopausal women: can it help differentiate benign from malignant causes of endometrial thickening?

PURPOSE: To determine if prominent vascularity and low pulsatility index (PI) and resistive index (RI) in endometrial arteries help differentiate carcinoma from benign lesions. MATERIALS AND METHODS: Forty-five postmenopausal women with at least 8-mm-thick endometrium at endovaginal ultrasound (US) underwent color duplex Doppler endovaginal US of the endometrium. PI and RI values were recorded from arterial waveforms generated in areas of increased vascularity. RESULTS: At color duplex Doppler endovaginal US, endometrial arterial flow was seen in 23 of 36 (64%) proved benign endometrial lesions. The range of PIs for benign lesions was 0.31-1.77 (mean, 0.72 +/- 0.33 [standard deviation]) and for RIs was 0.27-0.84 (mean, 0.48 +/- 0.13). Arterial vessels were seen in five of nine proved endometrial cancers (56%); the range of PIs was 0.42-1.17 (mean, 0.71 +/- 0.32) and for RIs was 0.34-0.69 (mean, 0.48 +/- 0.15). Differences in mean PI and RI for benign and malignant lesions were not significant. CONCLUSION: Low-impedance arterial flow is observed in various diseases of the endometrium, and there is an overlap between the PI and RI of benign and malignant lesions.

Aged↗