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Biomedical subjects

R Schwartz

Publications and source records attributed to R Schwartz.

At least 55 records · Page 3Linked to original sources
PubMed1999

Sparfloxacin versus ciprofloxacin for the treatment of community-acquired, complicated skin and skin-structure infections.

Fluoroquinolones have been shown to be effective in the treatment of complicated skin and skin-structure infections, in part because of their broad-spectrum antibacterial activity against causative pathogens that are resistant to older antimicrobial agents. We enrolled 603 adult patients (>58% male, >85% white) in a double-masked, double-dummy, randomized, multicenter trial to compare the efficacy and tolerability of sparfloxacin (400-mg loading dose followed by 200 mg once daily) with those of ciprofloxacin (750 mg twice daily) for 10 days in the treatment of community-acquired, complicated skin and skin-structure infections. The primary efficacy variable was clinical response, based on assessment of signs and symptoms, in the clinically assessable population. Patients in the sparfloxacin and ciprofloxacin groups were comparable with respect to demographic characteristics, underlying diseases, medical history, and laboratory test results. Wound infection was the most common diagnosis, and Staphylococcus aureus was the most frequently isolated pathogen. For the 475 clinically assessable patients, the clinical success rate (percentage of patients cured or improved) was 90.1% (210/233) with sparfloxacin and 87.2% (211/242) with ciprofloxacin. In this analysis (95% confidence interval [CI], -2.8 to 8.6) and the intent-to-treat analyses (95% CI, -4.2 to 6.2), results with sparfloxacin were statistically equivalent to those with ciprofloxacin (95% CI, -1 to 15.3). For bacteriologically assessable patients, eradication rates were 87.0% (141/162) with sparfloxacin and 79.9% (123/154) with ciprofloxacin (95% CI, -1 to 15.3). Eradication rates of S. aureus and coagulase-negative staphylococcal infections were 90.2% (101/112) with sparfloxacin and 77.9% (88/113) with ciprofloxacin. For patients with 2 or more pathogens at baseline (mixed infections), bacteriologic success was 87.6% for sparfloxacin and 77.9% for ciprofloxacin. Pseudomonas aeruginosa infections were eradicated or presumed eradicated in 71.4% (10/14) of sparfloxacin-treated patients and 87.5% (7/8) of ciprofloxacin-treated patients. Overall success rates in the bacteriologically assessable patients for sparfloxacin (84.6% [137/162]) and ciprofloxacin (78.6% [121/154]) were statistically equivalent (95% CI, -2.5 to 14.5). Tolerability was assessed in all patients who received study medication. The overall frequency of treatment-related adverse events was comparable in the 2 treatment groups (26.5% sparfloxacin, 23.3% ciprofloxacin). Drug-related adverse events involving the digestive system occurred in 7.1% of sparfloxacin-treated patients and 19.0% of ciprofloxacin-treated patients; photosensitivity reactions were reported in 11.1% of patients in the sparfloxacin group and 0.7% of patients in the ciprofloxacin group (P < 0.001). The mean change in QTc interval from baseline to the maximum on-treatment value was greater in the sparfloxacin group (9 milliseconds) than in the ciprofloxacin group (3 milliseconds) (P = 0.005; 95% CI, 0.002 to 0.010). The efficacy of sparfloxacin was comparable to that of ciprofloxacin in the treatment of community-acquired, complicated skin and skin-structure infections, including those caused by staphylococci, the most common pathogens. Sparfloxacin's once-daily regimen, high skin-tissue penetration, and improved activity against gram-positive cocci make it a therapeutic alternative to ciprofloxacin for patients who are not at risk for photosensitivity reactions or adverse events associated with prolongation of the QTc interval.

Adult↗
PubMed1999

Transsphenoidal resection of pituitary adenomas in an intraoperative MRI unit.

BACKGROUND: Transsphenoidal resection is a well known surgical procedure used in the treatment of sellar and parasellar lesions. In certain cases, operative identification of the lesion and achieving a complete resection can be problematic. We describe a surgical image guidance method using an intraoperative MRI which provides definitive identification of a lesion and verification of a complete resection. MATERIAL AND METHODS: Five patients with pituitary macroadenomas underwent transsphenoidal resection of their tumors in the intraoperative MRI unit at the Brigham and Women's Hospital. This unit was developed as a collaboration between General Electric and BWH and is an open configuration 0.5 Tesla MR imager in which surgery can be performed with real time, intraoperative MR guidance. RESULTS: The transsphenoidal resections were performed in a standard fashion in this unit. Intraoperative imaging allowed accurate localization of the lesions, identification of pertinent surrounding structures, and the evaluation of the extent of each resection. In two patients, the resection would have been considered complete based on the surgical field of view alone but MR imaging allowed remaining tissue to be identified. Developing clot was seen in one patient after a fat graft had been placed. CONCLUSION: The intraoperative MR is a surgical modality by which transsphenoidal resection of pituitary macroadenomas can be performed using real-time image guidance. It allows definitive identification of the tumor and an immediate evaluation of whether resection is complete. It also can monitor the occurrence of intraoperative complications such as hemorrhage. This revolutionary device can be an important tool for the surgical management of pituitary tumors.

Adenoma↗
PubMed1999

[Severe ocular injuries caused by fishing equipment].

BACKGROUND: Severe ocular injuries due to fishing equipment are rare, almost exclusively involve the anterior segments of men, and bear a bad prognosis. We report on two men and one woman with different etiologies of accidents. PATIENTS: In two men (53 and 39 yrs. OD and OS) and one woman (27 yrs., OD) a choroidal rupture due to a lead weight and subsequent choroidal neovascularisation (1x), temporal and nasal scleral and retinal lacerations (2x) due to a fish pick and a fish hook were noted. A laceration of the m. rectus int. (1x), uveal and retinal prolapse (1x), traumatic aniridia and aphakia (1x), a 12 and a 15 mm corneoscleral perforation temporal and nasal resp. including a retinal incarceration, a giant retinal tear 270 degrees, and vitreous and subretinal hemorrhage were seen. SURGERY: Interventions included 2x tight wound closure, 3x ppv, retinotomies (1x) endolasercoagulation (3x), silicone oil instillation (3x), muscel refixation (1x), and posterior lens implantation (1x). Subsequent surgery were silicone oil removal (2x) and membrane peeling (1x). RESULTS: An anatomical reconstruction was achieved in all of the patients, and the best postoperative visual acuity was gained after 4-6 months (+6.0 sph (2x) = 0.5, and +4.0 sph (1x) = 0.3). Silicone oil was removed after 4 and 13 months resp. followed by hypotony and redetachments, in one patient with silicone oil in place vision remained stable for > 2 years up to now at 0.5. CONCLUSIONS: Accidents due to fishing equipment may result in lacerations and contusions and involve women as well as. Surgery for extensive lacerations and complications of choroidal ruptures may not be hopeless, however, the prognosis for subsequent interventions is not good. Indications to remove silicone oil in eyes bearing a relative ciliary body insufficiency due to a long-standing insufficient wound closure should be done very cautiously.

Adult↗
PubMed1999

Lattice simulations of aggregation funnels for protein folding.

A computer model of protein aggregation competing with productive folding is proposed. Our model adapts techniques from lattice Monte Carlo studies of protein folding to the problem of aggregation. However, rather than starting with a single string of residues, we allow independently folding strings to undergo collisions and consider their interactions in different orientations. We first present some background into the nature and significance of protein aggregation and the use of lattice Monte Carlo simulations in understanding other aspects of protein folding. The results of a series of simulation experiments involving simple versions of the model illustrate the importance of considering aggregation in simulations of protein folding and provide some preliminary understanding of the characteristics of the model. Finally, we discuss the value of the model in general and of our particular design decisions and experiments. We conclude that computer simulation techniques developed to study protein folding can provide insights into protein aggregation, and that a better understanding of aggregation may in turn provide new insights into and constraints on the more general protein folding problem.

Algorithms↗
PubMed1999

The Physical Activity for Total Health (PATH) Study: rationale and design.

PURPOSE: Physical activity has been associated with a decreased risk for breast cancer. Mechanisms for this association may involve hormonal pathways. The Physical Activity for Total Health study is testing the effect of a 1-yr moderate intensity physical activity intervention on the endogenous sex hormone profile of postmenopausal women in a randomized controlled study. METHODS: Women (N = 168) who are aged 55-75 yr, not using sex hormones, sedentary, nonsmokers, have no endocrine-related disease or cancer, and with body mass index of 25.0 or greater, are eligible. Women are recruited through mass mailings and media advertising and are randomized to either a 1-yr moderate intensity aerobic and strength training exercise program (monitored group exercise sessions plus home exercise) or a control program (stretching classes). RESULTS: Serum hormones to be assayed at baseline and at the end of the study include: total estrone, total estradiol, free estradiol, percent bioavailable estradiol, estrone sulfate, sex hormone binding globulin, albumin, testosterone, free testosterone, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, insulin, glucose, and triglycerides. Other outcome measures include: the ratio of urinary 2-hydroxyestrone: 16alpha-hydroxyestrone (an estrogen metabolite ratio that may be associated with risk for breast cancer), weight, body mass index, total fat mass, and body fat distribution (waist:hip circumference ratio, DEXA scan, and abdominal fat measured by computed tomography). CONCLUSION: This study is the first to examine the effect of change in physical activity level on sex hormones in postmenopausal women. It will provide insight into possible mechanisms through which physical activity might be associated with reduced risk of breast cancer.

Aged↗
PubMed1999

Intravascular brachytherapy physics: report of the AAPM Radiation Therapy Committee Task Group no. 60. American Association of Physicists in Medicine.

Recent preclinical and clinical studies indicate that irradiation using ionizing radiation in the dose range of 15 to 30 Gy may reduce the occurrence of restenosis in patients who have undergone an angioplasty. Several delivery systems of intravascular brachytherapy have been developed to deliver radiation doses in this range with minimal normal tissue toxicity. In late 1995 the American Association of Physicists in Medicine (AAPM) formed a task group to investigate these issues and to report the current state of the art of intravascular brachytherapy physics. The report of this task group is presented here.

Angioplasty, Balloon, Coronary↗
PubMed1999

Identification of a subset of common variable immunodeficiency patients with impaired B-cell protein tyrosine phosphorylation.

The mechanisms responsible for common variable immunodeficiency syndrome (CVID) are as yet unknown. In the present study, we show that the B-cell dysfunction in a subset of CVID patients is caused by defective protein tyrosine phosphorylation (PTP). We demonstrated that the PTP level and immunoglobulin (Ig) secretion malfunctions can be successfully repaired when normal plasma membrane components are implanted into these patients' B cells. Stimulation of CVID patients' peripheral blood mononucleated cells with anti-Ig antibody revealed that 7 of 11 patients had lower PTP levels than those found in the normal donor cells. Plasma membrane implantation to the cells of these patients resulted in elevated PTP levels which reached normal levels upon stimulation with anti-human Ig antibody. The results revealed two distinct groups of CVID patients. The first group included patients whose B cells expressed low PTP levels after Ig stimulation. In these patients the plasma membrane implantation restored the normal PTP level as well as the ability to secrete IgM and/or IgG after B-cell stimulation. In the second group, patients whose B cells expressed a normal PTP level after Ig stimulation, with no restoration of their ability to secrete Ig upon plasma membrane implantation and lipopolysaccharide stimulation. We conclude that the first group has an early signal transduction defect located in the B-cell plasma membrane, while in the second group the defect is located elsewhere.

Adult↗
PubMed1999

What is the significance of macrosomia?

This commentary/review briefly considers the diverse criteria recommended for classification of overweight infants. Macrosomia continues to be a vexing problem for both obstetricians and pediatricians. Among the various techniques possible for use in assessing body composition, none are more practical than body weight relative to gestational age. The criteria for normative data from large populations are reviewed. The stringent definition, i.e., exceeding +2 SD of an appropriate normative population, is reaffirmed. Using these criteria, infants of diabetic mothers showed a significant relationship of body weight to fetal hyperinsulinemia.

Birth Weight↗
PubMed1999

My needlestick.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Maternal expressed emotion and adjustment in children with epilepsy.

Epilepsy in childhood may alter family relationships but the relevance of these changes for the increased rates of psychopathology has been little investigated. This study uses maternal expressed emotion (EE) to examine family relationships of children with epilepsy and the association with high risk for psychiatric disorder. EE was assessed using the Camberwell Family Interview carried out with the mothers of 22 schoolchildren with chronic epilepsy who were attending a general hospital outpatient clinic. Sixteen of these children had similarly aged healthy siblings who served as controls. High risk for psychiatric disorder in the children and mothers was assessed using behavioural, mood, and self-esteem questionnaires completed by mothers, teachers, and children. It was found that mothers showed significantly more emotional overinvolvement and a trend for more hostility towards their children with epilepsy than towards sibling controls. For the 22 children with epilepsy, maternal emotional overinvolvement was not associated with child behavioural deviance. High levels of criticism and, to a lesser extent, hostility did show associations with child behavioural deviance, and the strongest links were between maternal criticism and maternal rated antisocial and overactive behaviour in the child. Fewer positive comments by mothers towards the children were associated with child emotional symptoms and lower self-esteem in a number of areas. This study suggests that further research could consider the appropriateness of psychological intervention for families in which mothers are critical and hostile and whose children show antisocial behaviour.

Adaptation, Psychological↗
PubMed1999

Evaluating programs for recruiting and retaining community faculty.

BACKGROUND AND OBJECTIVES: There is a need to develop ambulatory care components within medical schools and, accordingly, a need to recruit community faculty. To assist in recruiting and retaining community faculty, this study addresses factors influencing physicians' decisions to serve as preceptors. The study also examines the relative value of incentives as rated by physicians in different primary care specialties. METHODS: We surveyed community physicians affiliated with a large, public teaching hospital. Physicians rated prior experiences training students in ambulatory settings, plans for serving as preceptors within the next year, and 7 incentives for serving as preceptors. RESULTS: A path analysis indicated that prior experiences and student influence on patient care affected future decisions to serve as preceptors. Analysis of the incentives for serving as preceptors indicated that physicians rated receiving continuing medical education (CME) credit the most favorably and financial compensation the least favorably. Overall, family physicians assigned the highest ratings to the incentives, and gynecologists gave the lowest ratings. CONCLUSIONS: This study produced a better understanding of the factors influencing physicians' decisions to serve as preceptors. Physicians are more concerned about students' influence on patient care than they are about students' influence on patient billings. In addition, preceptors preferred receiving nonmonetary compensation, such as CME credit, rather than receiving financial compensation. In addition, this study suggests better ways to reward community physicians for their service as preceptors. Community faculty should not be viewed as a homogenous group. The results of this study suggest that community physicians be provided with choices regarding the incentives for and rewards associated with serving as preceptors.

Ambulatory Care↗
PubMed1998

Novel nonnucleoside inhibitors of HIV-1 reverse transcriptase. 7. 8-Arylethyldipyridodiazepinones as potent broad-spectrum inhibitors of wild-type and mutant enzymes.

Like other nonnucleoside inhibitors of HIV-1 reverse transcriptase, the dipyridodiazepinone nevirapine (Viramune, 1) selects for drug resistant variants of HIV-1, both in cell culture and in patients. In particular, the mutation of residue 181 from tyrosine to cysteine (Y181C) is associated with resistance to most reported nonnucleoside inhibitors. Introduction of an arylethyl substituent at the 8-position of the tricyclic dipyridodiazepinone skeleton confers enhanced potency against Y181C RT. Several analogues of this series display good broad spectrum potency against a panel of mutant enzymes.

Amino Acid Substitution↗
PubMed1998

Novel nonnucleoside inhibitors of HIV-1 reverse transcriptase. 8. 8-Aryloxymethyl- and 8-arylthiomethyldipyridodiazepinones.

Nevirapine (I) is the first human immunodeficiency virus type 1 (HIV-1) nonnucleoside reverse transcriptase (RT) inhibitor to reach regulatory approval. As a result of a second generation program around the tricyclic core system of nevirapine, 2-chloro-5, 11-dihydro-11-ethyl-5-methyl-8-(2-(pyridin-4-yl)ethyl)-6H-dipyrido[3, 2-b:2',3'-e][1,4]diazepin-6-one (II)1a and 2-chloro-5, 11-dihydro-11-ethyl-5-methyl-8-phenylethyl-6H-dipyrido[3,2-b:2', 3'-e][1,4]diazepin-6-one (III)1a were identified as broad spectrum HIV-1 RT inhibitors. A detailed examination of replacing either of the methylenes of the 8-ethyl linker of II or III is presented. It was found that 8-aryloxymethyl and 8-arylthiomethyl are the preferred pattern of substitution for potency against RT. The most potent compounds were further evaluated against a panel of clinically significant mutant RT enzymes (K103N, V106A, G190A, P236L) and in cytotoxicity and in vitro metabolism assays. The most potent compound was 2-chloro-8-phenylthiomethyl analogue 37 which displayed sub-100 nM activity against all HIV-1 RT enzymes tested.

Animals↗
PubMed1998

Interleukin-12 enhances the virus-specific interferon gamma response of pigs to an inactivated pseudorabies virus vaccine.

Cell-mediated immunity is a major component of the host defense system against viral infections. Since interleukin (IL)-12 has been shown to be a potent stimulus for the in vivo generation of interferon-gamma (IFN-gamma)-producing T cells (i.e. Th-1 cells) in laboratory animals, we evaluated the effect of IL-12 on the cellular immune response of pigs to vaccination against pseudorabies virus (PrV), a herpesvirus of swine. The magnitude of the cellular immune response was measured by IFN-gamma ELISPOT analysis of peripheral blood mononuclear cells (PBMC) from pigs which had been immunized twice, at 2-week intervals, with either, modified live virus (MLV) alone or with a commercial inactivated PrV vaccine with or without the coadministration of human recombinant IL-12 (HrIL-12). No significant differences in the titer of virus-neutralizing antibodies or in the intensity of the virus-specific lymphoproliferative response among the different treatment groups was observed. However, the number of virus-specific IFN-gamma-producing cells among PBMC isolated from animals receiving the MLV vaccine was on average 3.5 times more than animals immunized with the inactivated vaccine (P = 0.01). Administration of the inactivated vaccine and IL-12 induced a two-fold higher frequency of virus-specific IFN-gamma-producing cells from that induced by the inactivated vaccine alone (P < 0.05). Despite this enhancement, the level of protection from lethal PrV challenge provided by the inactivated vaccine in combination with IL-12 was the same as that induced by the inactivated vaccine alone. Both of these vaccination regimes provided significantly lower levels of protection than those afforded by the MLV vaccine. This study demonstrates that an inactivated PrV vaccine is a poor inducer of virus-specific IFN-gamma-producing cells and that this response can be enhanced by administration of exogenous IL-12. The data provides evidence of a dichotomy in the humoral and cellular immune responses of pigs to a viral antigen and implies the existence of a Th-1/Th-2 type regulation of the anti-viral immune response in pigs.

Adjuvants, Immunologic↗
PubMed1998

Surgical treatment of low-grade gliomas in the intraoperative magnetic resonance imager.

Radical resection of low-grade gliomas can decrease the incidence of recurrence, the time to tumor progression, and the incidence of malignant transformation. The authors present a series of 25 patients who underwent craniotomy and resection of low-grade tumor in an intraoperative magnetic resonance (MR) imager. This is an open configuration 0.5-tesla imager developed by The Brigham and Women's Hospital and General Electric, in which a patient can be placed to undergo surgery. Gross-total removal was accomplished under real-time image guidance. These intraoperative images allow definitive localization and targeting of the lesions and accommodate anatomical changes that may occur during surgery. The authors consistently found that the extent of abnormality seen on the intraoperatively obtained films of resection was larger than that apparent in the surgical field of view alone. Intraoperative imaging made accurate surgical identification of these abnormal areas and subsequent resection possible. Patients with tumors adjacent to or within motor or language cortex underwent resection while awake, with monitoring of neurological function. In these cases, an aggressive resection without increased neurological morbidity was accomplished using the image guidance in conjunction with serial testing. A 1-month postoperative MR image was obtained in all patients. These correlated with the final intraoperative images obtained after the resection was completed. Only one patient had a mild postoperative deficit that remained at the 1-month follow-up examination. As the long-term outcome in patients with low-grade gliomas has been shown to correspond to the degree of resection, surgical resection in which intraoperative MR imaging guidance is used can be an invaluable modality in the treatment of these tumors.

Journal Article↗
PubMed1998

Protein size resolution in human eye lenses by dynamic light scattering after in vivo measurements.

Dynamic light scattering (DLS) measurements were conducted with lowest intensity levels on human eye lenses (3.2 mW/cm2) within measurement times of 3-5 s. A characterisation of the human eye under in-vivo conditions along the optical axis is given and a careful interpretation of the data is made, referring not only to in-vitro results of investigated solutions of lens chemistry and various crystallin fractions but also to measurements performed on intact human lenses under various scattering angles. The clinical study was expanded to 79 subjects with ages varying from 9 to 85 years with no serious diseases of the ocular lenses. A normalisation of Scheimpflug photography density data to the data obtained by DLS enables comparison of the two techniques and shows good agreement. The bimodal character of the viscoelastic properties of healthy eye lenses was confirmed; with an assumed viscosity of 2 cP, the mean size parameter of the smaller component is 5.13 +/- 1.6 nm and of the polymeric fraction 690 nm.

Adolescent↗