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J Bernstein

Publications and source records attributed to J Bernstein.

At least 37 records · Page 2Linked to original sources

Graph-set analysis of hydrogen-bond patterns: some mathematical concepts

To provide a foundation for further theoretical and software development of the application of graph sets to patterns of hydrogen bonding and other intermolecular interactions a number of mathematical concepts and tools are defined, developed and demonstrated. Following a review of the basic definitions and uses of graph sets, the directional properties of hydrogen bonds are now included in the treatment. The concepts of a constructor graph and covalent distance matrix have been developed to aid in the generation of a qualitative descriptor for the straightforward, consistent and ultimately automatic (with appropriate software) definition of patterns. An additional mathematical tool, the arrowed T-labeling, has been developed to deal with situations in which pattern-forming moieties are located on crystallographic special positions. To demonstrate the utility and various features of these concepts they are applied in detail to two particular structures, polymorphic iminodiacetic acid [N-(carboxymethyl)glycine] and trans-tetraamminedinitrocobalt(III) acetate. To facilitate the application and use of graph sets many of these developments have already been incorporated into the software of the Cambridge Structural Database, as described in the accompanying paper.

Journal Article↗

[Repair of female urinary incontinence with prolene "TVT": preliminary results of a multicenter and prospective survey].

OBJECTIVES: A multicentre, prospective study (6 private centres, 1 general hospital and 1 teaching hospital) was conducted to evaluate the perioperative morbidity and short-term functional results of the TVT procedure in the treatment of the female urinary stress incontinence. PATIENTS AND METHODS: From November 1996 to September 1999, 120 patients with a mean age of 65.2 years (range: 37-91) were operated according to the tension-free vaginal tape (TVT) technique for isolated urinary stress incontinence (stage 2 or 3) in 94 cases and associated with pelvic tone disorder in 26 cases. 59 patients (49.2%) presented recurrence of urinary incontinence that had already been operated between 1 and 4 times. Physical examination demonstrated hypermobility of the urethra in 73 cases (60.8%), isolated clinical sphincter incompetence in 47 cases (39.2%) and pelvic tone disorders in 31 cases. Urodynamic studies, performed in 113 patients, demonstrated sphincter incompetence in 65 cases (57.5%) with a mean maximum urethral closure pressure of 18 cmH2O (range: 5-29). RESULTS: The operation, performed under spinal anaesthesia in 97 cases (80.8%), general anaesthesia in 16 cases (13.3%) and local anaesthesia in 7 cases (5.8%) lasted an average of 28.7 min (range: 15-60) for insertion of the TVT. Perioperative complications consisted of twelve bladder injuries (10%) and two pelvic haematomas (1.7%). No cases of infection, erosion or migration of the tape were reported. In the group of 94 patients operated exclusively by TVT, the mean hospital stay was 2.6 days (range: 1-7). Twelve patients (10%) required self-catheterization for 2 to 30 days. With a mean follow-up of 15.2 months (range: 36-6), continence was restored in 104 patients, corresponding to a cure rate of 86.7%. A marked improvement was obtained in 11 cases (9.2%) and five cases (4.2%) were considered to be failures. CONCLUSION: The TVT procedure is a new approach to the treatment of female urinary stress incontinence. Its advantages are its simplicity, the rapidity of the technical procedure and the short-term efficacy on continence. A longer follow-up is essential to assess to the functional outcome and the long-term urethral tolerance.

Adult↗

Concomitant Polymorphs.

The simultaneous appearance of polymorphs of a substance has long been recognized but rarely noted or systematically studied. This phenomenon can be useful in the investigation of solid materials and in understanding the relative crystal energetics of polymorphic materials. This review covers the thermodynamic and kinetic factors that govern competitive and concomitant polymorphic crystallization. One of the many examples surveyed is a cyanine/oxonol complex, for which different relative molecular orientations in two of the many reported polymorphs are shown.

Journal Article↗

Graph-set analysis of hydrogen-bond patterns: some mathematical concepts.

To provide a foundation for further theoretical and software development of the application of graph sets to patterns of hydrogen bonding and other intermolecular interactions a number of mathematical concepts and tools are defined, developed and demonstrated. Following a review of the basic definitions and uses of graph sets, the directional properties of hydrogen bonds are now included in the treatment. The concepts of a constructor graph and covalent distance matrix have been developed to aid in the generation of a qualitative descriptor for the straightforward, consistent and ultimately automatic (with appropriate software) definition of patterns. An additional mathematical tool, the arrowed T-labeling, has been developed to deal with situations in which pattern-forming moieties are located on crystallographic special positions. To demonstrate the utility and various features of these concepts they are applied in detail to two particular structures, polymorphic iminodiacetic acid [N-(carboxymethyl)glycine] and trans-tetraamminedinitrocobalt(III) acetate. To facilitate the application and use of graph sets many of these developments have already been incorporated into the software of the Cambridge Structural Database, as described in the accompanying paper.

Journal Article↗

6-oxa isosteres of anacardic acids as potent inhibitors of bacterial histidine protein kinase (HPK)-mediated two-component regulatory systems.

A series of 6-oxa isosteres of anacardic acids (6-higher alkyl/alkenyl-2-hydroxybenzoic acids) was synthesised and several members were discovered to be among the most potent inhibitors (IC50 values < or = 5 microM) of the bacterial two-component regulatory systems, KinA/SpoOF and NRII/NRI, reported to date. The Gram-positive antibacterial activity in selected strains is also presented.

Anacardic Acids↗

Piperacillin/tazobactam plus tobramycin versus ceftazidime plus tobramycin for the treatment of patients with nosocomial lower respiratory tract infection. Piperacillin/tazobactam Nosocomial Pneumonia Study Group.

An open-label, randomized, comparative, multi-centre study was conducted at 25 centres in the USA and Canada to compare the safety and efficacy of piperacillin/tazobactam plus tobramycin with ceftazidime plus tobramycin in patients with lower respiratory tract infections. Piperacillin/tazobactam (3 g/375 mg) every 4 h or ceftazidime (2 g) every 8 h were administered i.v. for a minimum of 5 days. Tobramycin (5 mg/kg/day) given in divided doses every 8 h was administered to all patients. Patients with Pseudomonas aeruginosa isolated from respiratory secretions at baseline were to continue tobramycin for the duration of the study. Tobramycin could be discontinued in other patients after the baseline culture results were known. A total of 300 patients was randomized, 155 into the piperacillin/tazobactam group and 145 into the ceftazidime group. Of these, 136 patients (78 in the piperacillin/tazobactam group and 58 in the ceftazidime group) were considered clinically evaluable. Both groups were comparable for age, sex, duration of treatment and other demographic features. The clinical success rate in evaluable patients was significantly greater (P = 0.006) in the piperacillin/tazobactam treatment group (58/78; 74%) than in the ceftazidime group (29/58; 50%). Eradication of the baseline pathogen was significantly greater (P = 0.003) in the piperacillin/tazobactam group (66%) than in the ceftazidime group (38%). The clinical and bacteriological responses of those patients with nosocomial pneumonia were similar to the overall results. Twelve (7.7%) piperacillin/tazobactam-treated patients and 24 (17%) ceftazidime-treated patients died during the study (P = 0.03). Seven of the 24 deaths in the ceftazidime treatment group but only one of the 12 deaths in the piperacillin/tazobactam treatment group were directly related to failure to control infection. The majority of adverse events were thought by the investigator to be attributable to the patients' underlying disease and not drug related. In this study, piperacillin/tazobactam plus tobramycin was shown to be more effective and as safe as ceftazidime plus tobramycin in the treatment of patients with nosocomial LRTI.

Adolescent↗

Body mass and fracture risk. A study of 330 patients.

Low body mass is a major risk factor for low energy hip fractures among women. The purpose of this study was to ascertain whether normal body mass also protects against low energy wrist fractures. A retrospective analysis of body mass indices of 330 women who sustained hip or wrist fractures from falls was performed. Data were grouped by race and age. The mean body mass index for white patients with wrist fractures was 26.4, compared with a mean body mass index of 22.3 in white patients with hip fractures. For black patients, those with wrist fractures had a mean body mass index of 28.5, compared with a mean body mass index of 22.9 for those with hip fractures. Using data from The National Health and Nutrition Examination Surveys, the mean body mass index of patients with wrist fractures was seen to be equal to or greater than the national mean body mass index, whereas that of patients with hip fractures was substantially below average. Accordingly, normal body mass was protective against hip fractures but not against wrist fractures. Because adipose tissue more typically is distributed about the hip than the wrist, the protective mechanism of normal body mass against osteoporotic fractures may promote better preventative interventions against this disease.

Accidental Falls↗

Sabbatical programs and the status of academic emergency medicine: a survey.

OBJECTIVES: The Society for Academic Emergency Medicine (SAEM) commissioned a survey in 1998 to describe sabbatical programs, academic rank, and tenure, and to shed light on factors affecting the continuum of faculty development, as a context for evaluating the potential importance of emergency medicine (EM) sabbatical programs. METHODS: The chairs of 120 EM residency programs were surveyed. RESULTS: The response rate was 90%. Of 108 responses, 44 were academic EM departments (AEMDs); ten were their affiliates. The setting was urban for 82%; 37% were publicly funded and 58% privately. AEMDs were more likely to have a tenure track and eligibility for a sabbatical program, but not more likely to use a sabbatical program. Among 2,042 ranked EM faculty, there were 121 professors and 346 associate professors. Mean sabbatical length was six months, provided at full pay requiring a mean of 5.7 years of employment. Among 39 programs reporting eligibility for an EM sabbatical, requirements included: tenure (43%), academic rank of associate professor (78%), an application with multiple approval levels (92%), and a formal report (75%). Thirteen EM programs used sabbaticals; only 40 faculty members altogether (9% of senior faculty) have taken sabbaticals. The mean value of sabbaticals (rated by users on a scale of 1 to 10) was 6.8. Reduced funding, lack of departmental status, difficulty retaining faculty, Health Care Financing Administration (HCFA) regulations, graduate medical education (GME) cutbacks, and no release time were identified as challenges for emergency physicians (EPs) wishing to participate in sabbaticals. Strategies proposed to overcome these obstacles include quality customer service, streamlined operations, outside contracts, computerization, hiring individuals with PhDs, collaboration, political activity, and faculty development. CONCLUSIONS: A sabbatical can be beneficial for individuals and their institutions, but presently EPs have not been able to maximize use of available opportunities. Some obstacles to successful participation of EM in sabbatical programs might be overcome with creative strategies and the active support of professional academic organizations.

Career Mobility↗

Should higher income beneficiaries pay more for Medicare?

As Medicare cost increase, policymakers are searching for equitable ways to secure the program's financial base. Proposals that would require higher-income Medicare beneficiaries to pay a higher proportion of the program's costs are designed to increase beneficiaries' contribution without placing an unacceptable financial burden on those least able to afford it. Designing and implementing such a policy involves difficult tradeoffs in terms of revenue gains, burden on beneficiaries, and political support for Medicare over the long term.

Aged↗

Supplemental health insurance for Medicare beneficiaries.

Because Medicare leaves beneficiaries at risk for significant health care costs, most need to obtain some form of supplemental coverage to protect themselves against the financial burden of illnesses. Close to nine out of ten Medicare beneficiaries age 65 or older now have some health coverage that provides additional benefits beyond standard Medicare Part A and Part B. The most common types of supplementation are insurance coverage offered by former employers, policies that individual beneficiaries purchase, benefits offered by Medicare managed care plans and assistance provided through the Medicaid program. This supplementation is expensive--to beneficiaries, employers, states, and to the federal government. The availability and extent of financial protection offered by supplemental coverage provided by former employers and through managed care also appears to be increasingly unstable. Structural reform of the Medicare program needs to include a broad reexamination of the basic benefits package and of the potential benefits and costs of public and private supplementation of the health insurance coverage promised to beneficiaries.

Aged↗

Malignant tumors of the kidney, brain, and soft tissues in children and young adults with the tuberous sclerosis complex.

BACKGROUND: The tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by seizures, mental retardation, and benign tumors of the brain, heart, skin, and kidney. Malignant tumors also can occur in patients with tuberous sclerosis, particularly in the kidney, although they occur less frequently than benign tumors. The types of malignancy that occur in TSC have not been characterized fully. METHODS: Clinical and pathologic features of 8 malignant tumors from 6 TSC patients ranging in age from 22 months to 21 years are reviewed. Six tumors were renal, one was from the inguinal region, and one was from the brain. The tumors were analyzed for loss of heterozygosity (LOH) in the chromosomal regions of the TSC1, TSC2, and VHL genes. RESULTS: Three patients (ages 7, 8, and 20 years) had renal cell carcinomas (RCCs). Two of these patients had multifocal RCCs. All three patients with RCC also had prominent multifocal dysplasia of renal cyst epithelium. Two patients (ages 20 and 21 years) had malignant angiomyolipomas (1 renal and 1 inguinal). One patient (age 22 months) had a Grade 4 giant cell astrocytoma (glioblastoma multiforme). LOH in the region of the TSC2 gene was found, either in the malignant tumor or in benign tumors, in all five patients whose DNA could be analyzed. CONCLUSIONS: Children with TSC, as well as adults with the disease, are at risk for developing malignant tumors. Two types of renal malignancy occur in TSC: RCC, which appears to arise from dysplastic renal cyst epithelial cells, and malignant angiomyolipoma. Tumors cytologically similar to malignant angiomyolipomas also may occur at extrarenal sites. LOH analyses suggest that the majority of patients with TSC who develop malignant tumors have germline TSC2, rather than TSC1, gene mutations.

Adult↗