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Biomedical subjects

L Schwartz

Publications and source records attributed to L Schwartz.

At least 91 records · Page 5Linked to original sources
PubMed1996

Role of steroid dose in hypertension early after liver transplantation with tacrolimus (FK506) and cyclosporine.

Transplant immunosuppression using either cyclosporine (CsA) or tacrolimus (FK506) leads to renal vasoconstriction and nephrotoxicity. Despite producing similar effects within the kidney and blood vessels, clinical hypertension occurs less frequently with tacrolimus during the first year after transplantation, compared with CsA. To examine the role of steroid dose in early posttransplant hypertension, we measured blood pressure and kidney function in liver transplant recipients treated with tacrolimus and either high-dose (TAC-HI-P, n = 19) or low-dose (TAC-LO-P,n = 20) prednisone, compared with CsA-treated recipients (n = 29) receiving prednisone doses similar to the TAC-HI-P group. At 1 month, hypertension occurred more often with CsA (72%) than with TAC-HI-P (42%, P < 0.05) or TAC-LO-P (30%, P < 0.05). By 4 months after transplantation, hypertension developed in nearly twice as many TAC-HI-P (63%) as TAC-LO-P patients (32%, P < 0.05), with no difference between TAC-HI-P and CsA (86%, NS). Daily prednisone dose at 1 month closely paralleled cumulative steroid dose in the first month in the TAC-HI-P and TAC-LO-P groups. Fourteen of 19 TAC-HI-P patients (74%) required bolus steroids for treatment of rejection within the first month, compared with 3/20 (15%) TAC-LO-P and 10/29 (34%) CsA recipients. Glomerular filtration rate fell from pretransplant levels at 1 month and 4 months to the same degree in CsA, TAC-HI-P, and TAC-LO-P patients. These results demonstrate a central role for steroid dose in the rate of onset of hypertension early after liver transplantation using tacrolimus immunosuppression. Both daily dose and cumulative dosage, including bolus treatment for rejection, may impact on the development of hypertension. Since prevalence rates rise to levels comparable to CsA by 24 months regardless of steroid dose, hypertension after liver transplant may be mediated by different mechanisms at different stages of the posttransplant course.

Blood Pressure↗
PubMed1996

Angioplasty of isolated acute marginal coronary artery disease.

This report describes a patient who presented with a non Q wave myocardial infarction and post-infarction angina. Angiography revealed that his only significant disease was a severe lesion in an acute marginal branch of the right coronary artery. Balloon angioplasty was performed successfully with subsequent stabilization and no recurrence of angina in a 9-month follow-up. This case raises the possibility that acute marginal disease may contribute to ischemic syndromes and warrants consideration for revascularization.

Angina, Unstable↗
PubMed1996

The V-stent: a novel technique for coronary bifurcation stenting.

Intracoronary stenting as a transcatheter treatment for bifurcation stenoses remains controversial. A novel technique of coronary bifurcation stenting is reported. A 15 mm Palmaz-Schatz stent is bent 180 degrees at its bridge articulation into a V- configuration and mounted on two balloon-catheters linked together by adhesive tape. This unified stent delivery system was used successfully in five cases of porcine coronary bifurcation stenting.

Angioplasty, Balloon, Coronary↗
PubMed1996

Clinical applications of proton therapy.

Proton therapy offers considerable potential advantages in the management of poorly resectable, radio-resistent tumors close to critical anatomical structures. So far over 15,000 patients have been treated worldwide with two major indications: conservative management of ocular melanomas in which local control exceeds 95% at 5 years and curative irradiation of sarcomas at the base of the skull and cervical canal, with a survival rate between 84 and 94% at 5 years. The different protocols tested currently worldwide are discussed.

Adolescent↗
PubMed1996

Scleritis and mucosal-associated lymphoid tissue lymphoma: a new masquerade syndrome.

PURPOSE: To present a new masquerade syndrome showing features of mucosal-associated lymphoid tissue (MALT) lymphoma associated with choroidal white dots and scleritis. Differentials including systemic lymphoma, central nervous system lymphoma, and etiologies of white-dot syndromes and scleritis are discussed. PATIENTS AND METHODS: A 42-year-old man who had decreased vision and ocular redness of his right eye for 4 years had a biopsy-proven diffuse anterior and posterior scleritis associated with intense circumferential perilimbal chemosis and ipsilateral yellow-white choroidal dots. A new conjunctival biopsy was performed because of unresponsiveness to high-dose systemic steroid and cyclophosphamide therapy. Immunostains for lymphocyte markers were preformed. RESULTS: A morphologically and immunohistochemically typical, monotypical mu-kappa immunoglobulin light chain secreting B-cell MALT-lymphoma was diagnosed. Eighteen months after completion of radiotherapy, the patient recovered completely, except for the choroidal dots, which remained unchanged. CONCLUSION: When scleritis, even histologically proven, fails to respond to immunosuppressive therapy, a new biopsy is mandatory to rule out a misdiagnosed MALT lymphoma.

Adult↗
PubMed1996

Estrogen and progesterone receptor expression in endometrial polyps.

Endometrial polyps are a frequent cause of abnormal uterine bleeding, but their pathogenesis is poorly understood. This study was undertaken to investigate if endometrial polyps result from localized overexpression of estrogen receptors (ERs) or reduced expression of progesterone receptors (PRs). Fourteen cases of endometrial polyps, in which normal cycling endometrium was also present on the same slide, were immunostained for ERs and PRs. Percentages of positive cells in glands and stroma for each receptor were subjectively assessed to the nearest 5%. The intensity of staining was recorded on a scale from 1+ to 4+. The level and intensity of staining in polyps were compared with the staining in normal endometrium. Fewer stromal cells in polyps expressed ERs and PRs compared with cycling endometrium (% ER = 55.9 +/- 25.8 vs. 74.3 +/- 25.8, p = 0.03; % PR = 56.1 +/- 28.2 vs. 87.5 +/- 10.1, p = 0.002). Stroma in polyps also had significantly reduced intensity of staining for PRs, but not for ERs (intensity PR = 2.7 +/- 1.4 vs. 3.5 +/- 0.7, p = 0.015; intensity ER = 2.1 +/- 0.7 vs. 2.4 +/- 0.8, p = 0.45). There were no significant differences in expression of ERs and PRs in the endometrial glands in endometrial polyps compared with normal endometrium (% ER = 75.4 +/- 32.5 vs. 70.7 +/- 39.2. p = 0.25; % PR = 79.6 +/- 32.8 vs. 80.4 +/- 34.4, p = 0.8; intensity ER = 2.7 +/- 0.9 vs. 2.4 +/- 1, p = 0.15; intensity PR = 2.9 +/- 1.4 vs. 3.4 +/- 0.7, p = 0.15). We conclude that endometrial polyps may result from a decrease in ER and PR expression in stromal cells. Because of these receptor-negative stromal cells, endometrial polyps may be relatively insensitive to cyclic hormonal changes.

Adult↗
PubMed1996

Double-blind comparison of cefazolin and ceftizoxime for prophylaxis against infections following elective biliary tract surgery.

Antibiotics have been shown to reduce the incidence of wound infections after elective biliary tract procedures. Cefazolin and cefoxitin are among the agents most commonly promoted for this purpose. Cefoxitin has been substituted with ceftizoxime in many institutions; however, the role of ceftizoxime as a prophylactic agent in this setting has not been determined. To assess the comparative prophylactic efficacies of cefazolin and ceftizoxime in biliary tract surgery, we conducted a double-blind, randomized prospective clinical trial in a tertiary-care teaching hospital. Adult patients were randomized to one of two treatment groups and received a 30-min preoperative dose of study drug and as many as two postoperative doses at 12 and 24 h, depending on hospitalization status. Cefazolin and ceftizoxime were given as 1,000-mg doses. Patients with infections, those receiving prior antibiotics, or those with beta-lactam allergies were excluded. Over the 19-month study tenure, 167 patients were enrolled. Seventeen patients were excluded from analysis because of protocol violations. Of the 150 evaluable patients (72 and 78 receiving cefazolin and ceftizoxime doses, respectively), there was no significant difference among groups regarding sex, age, weight, preoperative Apache II score, baseline chemistry, and hematological parameters. Groups were also equivalent regarding the surgeon, type of procedure, characteristics (blood loss, drains, organ injury, and complications), and duration of hospital stay (mean, 5.6 versus 4.3 days [P = 0.31]). No clinical evidence of infection (7-day hospital stay and 30-day follow-up) was identified in 93% of cefazolin and 92% of ceftizoxime patients (P = 1.0). Microbiological confirmation was found in only 18% of primary-site infections. In conclusion, cefazolin and ceftizoxime appear to be equivalent for the prevention of infection in biliary tract surgery with the dosage regimens studied.

Adult↗
PubMed1996

Cell autonomous functions of the receptor tyrosine kinase TIE in a late phase of angiogenic capillary growth and endothelial cell survival during murine development.

TIE is a receptor tyrosine kinase expressed in both mature endothelial cells and their precursors, as well as in some hematopoietic cells. Mouse embryos homozygous for a disrupted Tie allele die at midgestation due to impaired endothelial cell integrity and resulting hemorrhage. Here we have performed chimeric analysis to study further the function of the murine TIE in the development of embryonic vasculature and in the hematopoietic system. Cells lacking a functional Tie gene (tie(lcz)/tie(lczn-) cells) contributed to the embryonic vasculature at E10.5 as efficiently as cells heterozygous for a targeted Tie allele (tie(lcz)/+ cells). Thus, TIE does not play a significant role in vasculogenesis or in early angiogenic processes, such as formation of the intersomitic arteries and limb bud vascularization. At E15.5 tie(lcz)/tie(lczn-) cells still readily contributed to major blood vessels and to endothelial cells of organs such as lung and heart, which have been suggested to be vascularized by angioblast differentiation. In contrast, the tie(lcz)/tie(lczn-) cells were selected against in the capillary plexuses of several angiogenically vascularized tissues, such as brain and kidney. Our results thus support a role for TIE in late phases of angiogenesis but not vasculogenesis. Furthermore, the results suggest that different mechanisms regulate early and late angiogenesis and provide support for a model of differential organ vascularization by vasculogenic or angiogenic processes. Analysis of adult chimeras suggested that TIE is required to support the survival or proliferation of certain types of endothelial cells demonstrating heterogeneity in the growth/survival factor requirements in various endothelial cell populations. Chimeric analysis of adult hematopoietic cell populations, including peripheral platelets and bone marrow progenitor cells, revealed that tie(lcz)/tie(lczn-) cells were able to contribute to these cell types in a way indistinguishable from tie(lcz)/+ or wild-type cells. Thus, the primary function of TIE appears to be restricted to the endothelial cell lineage.

Animals↗
PubMed1996

Nurse management of posttransplant hypertension in liver transplant patients.

Hypertension develops soon after organ transplantation using cyclosporine- or FK506-based immunosuppression. Sustained rises in blood pressure require intervention to reduce the risk of intracranial bleeding and other cardiovascular complications. Antihypertensive treatment is complicated by reduced renal function and potential interference with absorption and/or metabolism of cyclosporine or FK506. To manage early and long-term hypertension related to immunosuppression with cyclosporine or FK506 and prednisone following orthotopic liver transplantation, a comprehensive nurse-managed hypertension clinic was developed. Blood pressure, heart rate, and antihypertensive and immunosuppressive regimens were evaluated according to a standard protocol at 1, 4, 12, 24, and 36 months after orthotopic liver transplantation. Data indicate that posttransplantation hypertension develops within the first months after orthotopic liver transplantation and persists indefinitely. If comprehensively managed by the hypertension nurse-clinician, the percentage of controlled hypertension patients can increase over time.

Blood Pressure Monitoring, Ambulatory↗
PubMed1996

Initial report of rotational ablation: the Toronto Hospital experience.

OBJECTIVE: To describe the initial experience of rotational ablation (using the Rotablator device), in terms of safety and the effectiveness as a proportion of final angiographic outcome when combined with adjunctive balloon angioplasty. DESIGN: Retrospective analysis of single-centre experience, including operator learning curve. SETTING: Tertiary care hospital, Cardiac Catheterization Laboratory. PATIENTS: Consecutive subjects (14 men, 11 women) selected for rotational ablation based on ostial/bifurcation lesions (n = 10), 'long' (more than 10 mm) stenoses (n = 11) or extensive dystrophic calcification (n = 4). INTERVENTIONS: Rotational ablation (Rotablator) with routine adjunctive balloon angioplasty. Quantitative coronary arteriography using the Cardiac Measurement System. RESULTS: Rotational ablation reduced coronary obstruction, as demonstrated by minimal lumen diameter (preprocedure, 0.57 =/- 0.28 to 1.17 +/- 0.32 mm, P<0.05), with further improvements following adjunctive balloon angioplasty (1.93 +/- 0.35 mm). Similar changes were observed in relative stenosis after Rotablator (preprocedure, 79.7 +/- 7.6 to 56.1 +/- 13.1% diameter), with typical post-angioplasty residual narrowings (29.7 +/- 8.2% diameter). Estimated stenotic flow reserve was improved by the interventional procedures (preprocedure, 0.94 +/- 0.70; rotational ablation 3.07 +/- 1.14; and angioplasty, 4.73 +/- 0.25 times baseline). Complications were acceptable, and included three acute occlusions requiring balloon angioplasty recanalization and three non-Q wave myocardial infarctions (with creatine phosphokinase levels of 270, 417 and 602 IU, respectively). CONCLUSIONS: The Rotablator is a relatively user-friendly device with a reasonable safety profile, accounting for approximately 50% of minimum lumen diameter gains when used in conjunction with routine balloon angioplasty. The precise role of rotational ablation, particularly in the context of preselected lesion specific uses (bifurcations, long lesions, dystrophic calcification), requires prospective, randomized studies.

Adult↗
PubMed1996

The effects of in utero diagnostic X-irradiation on the development of preschool-age children.

High doses of X-irradiation may affect the developing human embryo and fetus, causing brain, eye, skeletal and other defects. Although the doses used in diagnostic irradiation are not considered to be high enough to cause fetal anomalies, it is unknown whether they affect the long-term development of the in utero exposed children. Using the Bayley or McCarthy developmental scales we examined 52 children born to mothers exposed to diagnostic X-irradiation of the abdomen and/or pelvis during the first trimester of pregnancy, 60 children born to mothers exposed during pregnancy (58 in the first trimester) to X-rays in areas other than the abdomen or pelvis, and 62 normal children without maternal exposure to X-rays during pregnancy. All children were aged 1-5 years at examination. Parental socioeconomic status was the same in all three groups. There were no differences in the results of the medical and neurological examination, and in the motor or congnitive scores among three groups. Embryonic or fetal exposure to X-irradiation in doses below 5 rads does not seem to have any effect on development during childhood.

Age Factors↗
PubMed1996

Coronary 'Y' stenting: a technique for angioplasty of bifurcation stenoses.

This report describes a case of successful percutaneous coronary transluminal angioplasty (PTCA) of a coronary artery bifurcating lesion using multiple intracoronary stents in an inverted 'Y' configuration. Balloon angioplasty of bifurcation coronary stenoses has a lower procedural success rate, higher restenosis rate and potential for side branch occlusion compared with nonbifurcation lesions. Numerous techniques, including two ('kissing') angioplasty balloons, have been used to overcome these problems. The authors believe that the technique described in this report, inserting stents into both branches simultaneously followed by a third proximal stent in a 'Y' configuration, allows successful dilatation of the bifurcation lesion while preserving flow into both branches and should be considered for similar complex anatomical subsets.

Aged↗
PubMed1995

[Apoptosis and cancer].

Apoptosis is a mode of active cell death having distinct biochemical and morphological features including chromatin condensation, polynucleosomal DNA fragmentation, and disruption of cells into apoptotic bodies. The apoptotic process plays a major role both during development and in the functioning of the immune system. Apoptosis may in part be genetically regulated, and may also be linked to physiological and non physiological signals from the environment. Apoptosis may be a defense at the cellular level against cancer. Moreover, there is evidence that a number of pro-oncogenes and tumor suppressor genes are involved in regulating apoptosis. Further understanding of the molecular events underlying the apoptotic process should provide new insights into the mechanism of tumorigenesis and facilitate the development of new strategies for the treatment of cancer.

Apoptosis↗
PubMed1995

A single center randomized trial assessing use of a vascular hemostasis device vs. conventional manual compression following PTCA: what are the potential resource savings?

We undertook a randomized controlled trial comparing VasoSeal, a collagen vascular hemostasis device (VHD), with manual compression to assess its role and potential cost savings in the PTCA population. Of 460 patients, 359 were excluded due to clinical instability (30%), groin problems (18%), suboptimal PTCA result (15%), and other reasons (37%). The remaining 101 patients were randomized to either VHD (51) or manual compression (50). Hemostasis time, time to ambulation, duration of hospital stay, and nursing time and intensity were significantly reduced in the VHD group. There were no major groin complications in either treatment arm but there was a trend toward more minor groin complications in the VHD patients. The application of VasoSeal reduced resource use in this randomized study and may translate into significant cost reductions in the general coronary angioplasty population.

Adult↗
PubMed1995

Clinical applications of proton therapy. Experiences and ongoing studies.

Proton therapy offers potentially considerable advantages in the management of slow-growing, poorly resectable or non-resectable tumors resistant to x-rays and located close to critical radiosensitive anatomical structures, such as the brain stem of the spinal cord. Among over 13,000 irradiated patients in the USA, Europe, and Japan, two major clinical indications have been documented: 1. The conservative management of choroidal melanomas, in which 98% 5-year local control can be expected at the price of low toxicity and visual preservation in approximately half of them. 2. The curative management of low-grade chondrosarcomas and chordomas of the base of the skull and cervical spine, leading to, in combination with maximal tumor resection, 84%-94% long-term survival. Other ongoing studies concern prostate, head and neck carcinomas as well as various intracranial tumors. Radiosurgical programs are being conducted generally with single fractions and under stereotactic conditions.

Bone Neoplasms↗
PubMed1995

Interferon alfa-2a and 13-cis-retinoic acid in renal cell carcinoma: antitumor activity in a phase II trial and interactions in vitro.

PURPOSE: A phase II trial of interferon alfa-2a (IFN) and 13-cis-retinoic acid (CRA) was conducted in patients with renal cell carcinoma (RCC). In vitro studies were performed to investigate potential mechanisms of interaction. PATIENTS AND METHODS: Forty-four patients were treated. IFN was given daily at 3 MU and escalated to 6 and 9 MU if tolerated. The dose of CRA was 1 mg/kg/d. The effects of combining CRA and IFN on the proliferation of five RCC cell lines were examined, and retinoid sensitivity was correlated to the expression of retinoic acid receptors. RESULTS: Thirteen (30%) of 43 assessable patients achieved a major response (three complete and 10 partial). Responding sites included bone metastases and renal primary tumors. Seven responding patients remain progression-free at 10+ to 19+ months. The response proportion was higher than in our prior experience with IFN, which was 10% in 149 patients. Eleven of 12 renal cancer cell lines were resistant to CRA alone; one, SK-RC-06, showed 90% inhibition of cell growth. CRA augmented the antiproliferative effect of IFN in several IFN-sensitive cell lines, but not in IFN-resistant lines. Northern blot analysis showed that expression of retinoic acid receptor-beta (RAR-beta) was repressed and not induced by retinoic acid in retinoic acid-insensitive RCC lines. However, RAR-beta expression was induced by retinoic acid in SK-RC-06 cells. CONCLUSION: IFN and CRA showed antitumor activity in patients with advanced RCC, and the proportion and nature of response suggested CRA added therapeutic benefit to IFN. A phase III randomized trial of IFN plus CRA versus IFN alone and a phase II trial of single-agent CRA have been initiated.

Adolescent↗