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Biomedical subjects

B Schwartz

Publications and source records attributed to B Schwartz.

At least 127 records · Page 7Linked to original sources
PubMed1997

Population-based surveillance for group A streptococcal necrotizing fasciitis: Clinical features, prognostic indicators, and microbiologic analysis of seventy-seven cases. Ontario Group A Streptococcal Study.

PURPOSE: To determine the incidence of group A streptococcal necrotizing fasciitis in Ontario, Canada, and to describe the clinical features, outcome, and microbiologic characteristics of this infection. PATIENTS AND METHODS: Prospective, population-based surveillance for invasive group A streptococcal infections was conducted in Ontario from November 1991 to May 1995. All 77 patients meeting clinical and/or histopathologic criteria for streptococcal necrotizing fasciitis were included. Demographic and clinical information was obtained by patient interviews and chart review. Group A streptococci were characterized by M-protein and T-agglutination typing, and polymerase chain reaction (PCR) detection of streptococcal pyrogenic exotoxin genes A and C (speA; speC). RESULTS: The incidence of group A streptococcal necrotizing fasciitis increased during the study from 0.085 per 100,000 population in the first year to 0.40 per 100,000 population in the last year (P < 0.001). The median age of cases was 57.5 years and the rate of disease increased with increasing age. Seventy-nine percent of cases were community-acquired, 11% were nosocomial, and 10% were acquired in a nursing home. Forty-seven percent of cases were associated with the presence of streptococcal toxic shock syndrome (Strep TSS) and 46% were bacteremic. Thirty-four percent of cases died and mortality was correlated with increasing age (P = 0.006), presence of hypotension (P = 0.01), and bacteremia (P = 0.03). The most common streptococcal serotypes were M1 (35%) and M3 (25%). Forty-one percent of strains possessed the speA gene and 30% the speC gene. Outcome was not correlated with M-type or the presence of spe genes. CONCLUSIONS: The incidence of necrotizing fasciitis caused by group A streptococcus increased in Ontario between 1992 and 1995. Elderly individuals were more likely to acquire the disease and to die from it. Mortality because of streptococcal necrotizing fasciitis was also associated with the presence of hypotension, Strep TSS, or bacteremia, but not with M-type or the presence of pyrogenic exotoxin genes.

Aged↗
PubMed1997

Reversal of spinal cord non-opiate analgesia by conditioned anti-analgesia in the rat.

The spinal cord contains endogenous substances (such as cholecystokinin, FMRFamide, etc.) that can block the analgesic effects of opiates. Anti-opiate actions have been most commonly studied by exogenous administration of receptor agonists and receptor antagonists of these substances. However, we have recently demonstrated that anti-analgesia can be brought under environmental control through Pavlovian conditioning. Whereas analgesia can be conditioned to signals for danger, anti-analgesia can be conditioned to signals for safety. Using this paradigm, we have previously demonstrated that conditioned anti-analgesia can reverse a variety of opiate analgesic states, including those produced by conditioned danger signals, systemic morphine, and intrathecal mu- and delta-opiate receptor agonists. These data raise the question of the generality of anti-analgesia actions. The present series of experiments examined the ability of conditioned anti-analgesia to affect non-opiate analgesic states induced by spinal delivery of GABA(A), GABA(B), 5HT2 + 5HT1, and 5HT3 receptor agonists. While conditioned anti-analgesia had no effect on GABA(A) or 5HT2 + 5HT1 non-opiate analgesias, conditioned anti-analgesia completely blocked GABA(B) and 5HT3 non-opiate analgesias. These findings clearly demonstrate that conditioned anti-analgesia can powerfully modulate non-opiate as well as opiate analgesias and bring into question whether putative anti-opiate neuroactive substances may have broader actions than previously suggested.

Analgesia, Epidural↗
PubMed1997

Computerized measurement of the three-dimensional distribution of optic disc pallor.

PURPOSE: To describe a method which provides quantitative measurements of the surface area of pallor in each quadrant of the three-dimensional optic cup, using photogrammetric measurements from simultaneous stereophotographs and computerized image analysis. METHODS: Simultaneous stereophotographs of one normal subject and two subjects with primary open angle glaucoma were digitized and analyzed for depth measurements. The boundaries of the optic disc, optic cup and region of pallor were identified. Pallor/disc and pallor/cup ratios were subsequently calculated for the superior, temporal, inferior and nasal walls. RESULTS: A digitized photograph and a Laplacian-filtered image were obtained for each eye to be studied. After processing each stereo pair through a similarity sequential detection-based algorithm, depth measurements are represented as a grey scale image, a contour plot, and a wire mesh, with the boundaries of the optic disc, optic cup and pallor superimposed. Ratios are given of the surface area of pallor to the surface area of the disc and the surface area of pallor to the surface area of the cup, by quadrant. CONCLUSIONS: Determination of surface area of pallor to cup may be useful in detecting early visual field loss in glaucoma and neurological disease.

Adult↗
PubMed1997

Handwashing and glove use in a long-term-care facility.

OBJECTIVES: To determine glove use and handwashing practices, the factors associated with infection control practices, and the frequency of potential microbial transmission in a long-term-care facility (LTCF). DESIGN: Observational study of 230 staff-resident interactions in an LTCF. We recorded resident characteristics, type of activity, staff credentials, and movements of the staff member's hands, then used the LTCF's guidelines to judge appropriateness of glove use and handwashing. SETTING: 255-bed, university-based LTCF in Baltimore, Maryland. PARTICIPANTS: A systematic sample of staff-resident interactions. RESULTS: Gloves were worn in 139 (82%) of 170 interactions when indicated, but changed appropriately in only 1 (16%) of 132. Hands were washed when needed before an interaction in 27%, during an interaction in 0%, and after an interaction in 63%. Gloves were less likely to be used when caring for residents with gastrostomy tubes compared with other residents (relative risk, 0.85; 95% confidence interval, 0.73-0.98). Guidelines were followed more frequently during wound care than during other activities. Microbial transmission potentially could have occurred in 158 (82%) of 193 evaluable interactions. CONCLUSIONS: We documented marked deficiencies in glove and handwashing, demonstrated the possible impact of these deficiencies, and identified factors associated with inadequate handwashing and glove use. This information can be used in future educational and research efforts to improve infection control practices.

Baltimore↗
PubMed1997

Enhanced ocular hypotensive response to epinephrine in rabbits with prior dexamethasone treatment.

The purpose of this study was to determine glucocorticoid modulation of ocular pressure to epinephrine applied topically to rabbit eyes that were pretreated with dexamethasone. Rabbit eyes were pretreated with five applications of topical 0.07% dexamethasone (0.1% dexamethasone phosphate) or saline drops, administered at ten minute intervals. The eyes were then treated with epinephrine bitartrate drops at concentrations of free base epinephrine of 1.1%, 0.27%, 0.05%, 0.027%, 0.005% or 0.0005%. An additional group of rabbits received dexamethasone pretreatment only. Intraocular pressure (IOP) was measured for the next four hours. Enhanced lowering of intraocular pressure was observed with dexamethasone pretreatment. Rabbits receiving the smaller dose of epinephrine with dexamethasone had the largest decrease in IOP at 135 minutes after instillation of the epinephrine drops (0.005% epinephrine, mean difference +/- standard error of mean = 5.4 +/- 1.1 mmHg). Similarly, the duration of significant decrease of the IOP was prolonged in the groups receiving the lower concentrations of epinephrine (0.005% epinephrine, 255 minutes after administration of epinephrine). The synergism between glucocorticoids and adrenergic agonists in lowering IOP may be potentially useful in the therapy of ocular hypertension and glaucoma.

Administration, Topical↗
PubMed1997

Emergence of antibody to capsular polysaccharides of Streptococcus pneumoniae during outbreaks of pneumonia: association with nasopharyngeal colonization.

Antibody to pneumococcal capsular polysaccharides (PPS) of Streptococcus pneumoniae plays a major role in protecting the host against pneumococcal infection. A variable proportion of healthy adults have antibody to PPS, often in the absence of recognized pneumococcal infection. To determine whether exposure to pneumococci or colonization by pneumococci, or both, stimulates the emergence of antibody to PPS, we studied outbreaks of pneumonia at two military camps. Of the men who were present at a military training camp during an outbreak of pneumonia due to S. pneumoniae serotype 1 but who did not develop pneumonia, 27.8% had IgG antibody to PPS 1, whereas only 3.6% of controls had this antibody. In another outbreak caused by S. pneumoniae serotypes 7F and 8, 35.9% of asymptomatic soldiers who had nasopharyngeal colonization by one of these strains had antibody to the relevant PPS, and another 30.8% who originally did not have antibody developed it within 30 days; thus, 66.7% of these soldiers had antibody to the relevant PPS. These data show that serotype-specific antibody promptly appears following exposure to an outbreak of pneumococcal pneumonia and is probably mediated through acquisition of nasopharyngeal pneumococcal carriage.

Adult↗
PubMed1997

Survey of emm gene sequences and T-antigen types from systemic Streptococcus pyogenes infection isolates collected in San Francisco, California; Atlanta, Georgia; and Connecticut in 1994 and 1995.

The variable 5' emm (M-protein gene) sequences and T-antigen types were determined from 340 systemic group A streptococcal (GAS) isolates taken from hospitalized patients in San Francisco, Calif.; Atlanta, Ga.; and Connecticut in 1994 and 1995. Eighty percent of these isolates had emm sequences and T-antigen types in agreement with previously recorded M- and T-antigen associations. Most of the remaining strains either were T nontypeable (11%) or contained emm genes encoding M proteins for which T-antigen associations have not been made (6%). One newly encountered emm gene, designated ST2974, from each of 13 isolates had the T type 8/25/Imp19. Another new emm gene, ST2967, from 8 of 11 isolates was T nontypeable. Six other unique emm gene sequences from seven isolates were encountered. Sequencing of the variable region of the emm gene of GAS isolates (emm typing) is effective for surveying the sequence variability of the M virulence protein, and combined with T typing, emm typing is useful for monitoring GAS strain diversity.

Amino Acid Sequence↗
PubMed1997

Mineralocorticoid receptors in the rabbit iris-ciliary body.

To demonstrate the presence of mineralocorticoid receptors, specifically aldosterone receptors, iris-ciliary body cytosol from New Zealand albino rabbits was incubated with increasing amounts (0.5-20.0 nM) of radiolabeled aldosterone in the presence and absence of a 100-fold excess of aldosterone. A glucocorticoid receptor blocker, RU-28362, was employed when various steroids were allowed to compete with aldosterone for binding sites on the aldosterone receptor. Aldosterone bound to two classes of receptor proteins. Scatchard analysis of the data indicated one component to bind aldosterone with high affinity (Kd = 2.2 x 10-9 M) and low capacity (Bmax = 32 fmol/mg protein). If the concentration of aldosterone is increased, it also binds to a second component, but with a lower affinity (Kd = 9.8 x 10-9 M) and greater capacity (Bmax = 64 fmol/mg protein).

Aldosterone↗
PubMed1997

Sulpiride augmentation in people with schizophrenia partially responsive to clozapine. A double-blind, placebo-controlled study.

BACKGROUND: We hypothesised that a combined regimen of clozapine, a relatively weak D2-dopaminergic antagonist, and sulpiride, a selective D2 blocker, would demonstrate a greater antipsychotic efficacy by enhancing the D2 blockade of clozapine. METHOD: Twenty-eight people with schizophrenia, previously unresponsive to typical antipsychotics and only partially responsive to current treatment with clozapine, received, double-blind, 600 mg/day sulpiride or placebo, in addition to an ongoing clozapine treatment. The clinical status was evaluated before, during, and at the end of 10 weeks of sulpiride addition using the Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Positive Symptoms (SAPS), Scale for the Assessment of Negative Symptoms, and Hamilton Rating Scale for Depression. RESULTS: The clozapine-sulpiride group exhibited substantially greater and significant improvements in positive and negative psychotic symptoms. About half of them, characterised by a younger age and lower baseline SAPS scores, had a mean reduction of 42.4 and 50.4% in their BPRS and SAPS scores, respectively. CONCLUSIONS: A subgroup of patients with chronic schizophrenia may substantially benefit from sulpiride addition to clozapine.

Adult↗
PubMed1997

Enhanced acute ocular hypotensive response to timolol with dexamethasone treatment.

PURPOSE: This study was conducted to determine whether low doses of dexamethasone can enhance the lowering of ocular pressure by low doses of timolol. PATIENTS AND METHODS: In 12 patients with untreated ocular hypertension and similar intraocular pressures in each eye, one eye was randomly selected in a masked manner for pretreatment with three applications of topical 0.01% dexamethasone sodium phosphate drops prepared in artificial tears. The other eye was treated with three applications of drops of artificial tears alone. Both eyes were then treated with 0.01% timolol maleate drops. Ocular pressure was measured for the next 100 minutes at 20-minute intervals. The study was done in an outpatient office. Twelve untreated ocular hypertensive patients participated in this study. RESULTS: When compared with eyes treated with timolol drops alone, eyes pretreated with dexamethasone drops showed a significantly greater decrease in ocular pressure (mean +/- SD); the maximal decrease in 12 dexamethasone-treated patients was 3.5 +/- 1.9 mm Hg (15.9% from baseline). Six dexamethasone-treated patients had a response of 4.0 to 6.0 mm Hg, whereas three showed responses < 4 and > 2 mm Hg with three < or = 2 mm Hg. CONCLUSIONS: This synergistic effect of timolol with dexamethasone on lowering of ocular pressure offers a potential therapeutic use in ocular hypertension and glaucoma.

Administration, Topical↗
PubMed1997

Resistant pneumococci: protecting patients through judicious use of antibiotics.

Increasing resistance to antimicrobial agents has occurred among many pathogens, but the emergence of resistant Streptococcus pneumoniae will have the greatest impact on the practice of outpatient medicine. Consequences of resistance include complicated management of acute otitis media and meningitis treatment failures. Pneumococci have acquired resistance to penicillin, third-generation cephalosporins and other antibiotics at an alarming rate; in some areas, 25 percent of isolates are nonsusceptible to penicillin. In areas with high resistance rates, the addition of vancomycin to cefotaxime or ceftriaxone is warranted for empiric treatment of bacterial meningitis. Changes in empiric therapy for pneumonia, bacteremia and otitis media may eventually be necessary. Previous antibiotic use is a risk factor for invasive disease with resistant pneumococci. Patients may be best protected by avoiding unnecessary use of antibiotics. Patient education materials as well as recommendations for avoiding the use of antibiotics for some upper respiratory tract infections are currently being developed to help physicians achieve this goal.

Anti-Bacterial Agents↗
PubMed1997

Gastrin levels in colorectal cancer.

Our objective was to determine whether colorectal cancer tissue synthesizes and secretes biologically active gastrins resulting in a rise of gastrin levels in patients with adenocarcinoma of the colon. Blood samples for gastrin determination were taken from the artery feeding, and from the vein draining colon tumors, from a vein draining an uninvolved colon segment and from a peripheral vein. Tissue gastrin levels were measured in tumor tissues and normal mucosa taken by colonoscopic biopsy from colon cancer patients and healthy controls. The setting was a university hospital research laboratory. We had seventeen patients with colorectal cancer and 23 controls. No significant difference was found in peripheral venous blood gastrin levels between the cancer and the control groups. Serum gastrin concentration was not significantly different in the arterial blood which supplied the tumor area, the venous blood draining the tumor, the "uninvolved" mucosa or the control normal epithelium. Cancer tissue gastrin levels were lower than those measured in biopsies of uninvolved mucosa from cancer patients and normal controls. The present results show no rise of gastrin blood levels in patients with colon cancer, nor any evidence of gastrin-increased synthesis by the tumors.

Adenocarcinoma↗
PubMed1997

Evaluation of an algorithm for integrated management of childhood illness in an area of Kenya with high malaria transmission.

In 1993, the World Health Organization completed the development of a draft algorithm for the integrated management of childhood illness (IMCI), which deals with acute respiratory infections, diarrhoea, malaria, measles, ear infections, malnutrition, and immunization status. The present study compares the performance of a minimally trained health worker to make a correct diagnosis using the draft IMCI algorithm with that of a fully trained paediatrician who had laboratory and radiological support. During the 14-month study period, 1795 children aged between 2 months and 5 years were enrolled from the outpatient paediatric clinic of Siaya District Hospital in western Kenya; 48% were female and the median age was 13 months. Fever, cough and diarrhoea were the most common chief complaints presented by 907 (51%), 395 (22%), and 199 (11%) of the children, respectively; 86% of the chief complaints were directly addressed by the IMCI algorithm. A total of 1210 children (67%) had Plasmodium falciparum infection and 1432 (80%) met the WHO definition for anaemia (haemoglobin < 11 g/dl). The sensitivities and specificities for classification of illness by the health worker using the IMCI algorithm compared to diagnosis by the physician were: pneumonia (97% sensitivity, 49% specificity); dehydration in children with diarrhoea (51%, 98%); malaria (100%, 0%); ear problem (98%, 2%); nutritional status (96%, 66%); and need for referral (42%, 94%). Detection of fever by laying a hand on the forehead was both sensitive and specific (91%, 77%). There was substantial clinical overlap between pneumonia and malaria (n = 895), and between malaria and malnutrition (n = 811). Based on the initial analysis of these data, some changes were made in the IMCI algorithm. This study provides important technical validation of the IMCI algorithm, but the performance of health workers should be monitored during the early part of their IMCI training.

Algorithms↗
PubMed1997

Identifying sick children requiring referral to hospital in Bangladesh.

The object of this study was to evaluate and improve the guidelines for the Integrated Management of Childhood Illness (IMCI) with respect to identifying young infants and children requiring referral to hospital in an area of low malaria prevalence. A total of 234 young infants (aged 1 week to 2 months) and 668 children (aged 2 months to 5 years) were prospectively sampled from patients presenting at a children's hospital in Dhaka, Bangladesh. The study paediatricians obtained a standardized history and carried out a physical examination, including items in the IMCI guidelines developed by WHO and UNICEF. The paediatricians made a provisional diagnosis and judged whether each patient needed hospital admission. Using the paediatrician's assessment of a need for admission as the standard, the sensitivity and specificity of the current and modified IMCI guidelines for correctly referring patients to hospital were examined. The IMCI's sensitivity for a paediatrician's assessment in favour of hospital admission was 84% (95% confidence interval (CI): 75-90) for young infants and 86% (95% CI: 81-90) for children, and the specificity was, respectively, 54% (95% CI: 45-63) and 64% (95% CI: 59-69). One fourth or more in each group had a provisional diagnosis of pneumonia, and the IMCI's specificity was increased without lowering sensitivity by modifying the respiratory signs calling for referral. These results show that the IMCI has good sensitivity for correctly referring young infants and children requiring hospital admission in a developing country setting with a low prevalence of malaria. The guidelines' moderate specificity will result in considerable over-referral of patients not needing admission, thereby decreasing opportunities for successful treatment of patients at first-level health facilities. The impact of the IMCI guidelines on children's health and the health care system must be judged in the light of current treatment practices, health outcomes and referral patterns.

Algorithms↗
PubMed1997

Evaluation of clinical signs to diagnose anaemia in Uganda and Bangladesh, in areas with and without malaria.

The object of this study was to assess the ability of pallor and other clinical signs, including those in the Integrated Management of Childhood Illness (IMCI) guidelines developed by WHO and UNICEF, to identify severe anaemia and some anaemia in developing country settings with and without malaria. A total of 1226 and 668 children aged 2 months to 5 years were prospectively sampled from patients presenting at, respectively, a district hospital in rural Uganda and a children's hospital in Dhaka, Bangladesh. The study physicians obtained a standardized history and carried out a physical examination that included pallor, signs of respiratory distress, and the remaining IMCI referral signs. The haematocrit or haemoglobin level was determined in all children with conjunctival or palmar pallor, and in a sample of the rest. Children with a blood level measurement and assessment of pallor at both sites were included in the anaemia analysis. Using the haematocrit or haemoglobin level as the reference standard, the correctness of assessments using severe and some pallor and other clinical signs in classifying severe and some anaemia was determined. While the full IMCI process would have referred most of the children in Uganda and nearly all the children in Bangladesh with severe anaemia to hospital, few would have received a diagnosis of severe anaemia. Severe palmar and conjunctival pallor, individually and together, had 10-50% sensitivity and 99% specificity for severe anaemia; the addition of grunting increased the sensitivity to 37-80% while maintaining a reasonable positive predictive value. Palmar pallor did not work as well as conjunctival pallor in Bangladesh for the detection for severe or some anaemia. Combining "conjunctival or palmar pallor" detected 71-87% of moderate anaemia and half or more of mild anaemia. About half the children with no anaemia were incorrectly classified as having "moderate or mild" anaemia. Anaemia was more easily diagnosed in Uganda in children with malaria. Our results show that simple clinical signs can correctly classify the anaemia status of most children. Grunting may serve as a useful adjunct to pallor in the diagnosis of severe anaemia. Conjunctival pallor should be added to the IMCI anaemia box, or the guidelines need to be adapted in regions where palmar pallor may not readily be detected.

Anemia↗