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Biomedical subjects

S J Rubin

Publications and source records attributed to S J Rubin.

47 records · Page 3Linked to original sources
PubMed1977

Clinical evaluation of commercial conjugates for direct immunofluorescence of herpes simplex virus.

Commercially prepared antibody conjugates that are now available allow extensive application of direct immunofluorescence for diagnosing herpetic infections. Five of these conjugates--Microbiological Associates bivalent herpes antiserum (MBA-bivalent), MBA anti-herpes types 1 (MBA-1) and 2 (MBA-2), and Flow Laboratories anti-herpes types 1 (Flow-1) and 2 (Flow-2)--were compared for antibody titer, diagnostic accuracy, and nonspecific background staining on known infected tissue. Four of these were tested simultaneously on 75 clinical specimens. No attempt was made to differentiate between herpes simplex virus type 1 or type 2 infections. All antisera were comparable in titer and exhibited fluorescence with both herpes simplex virus types 1 and 2 antigens. The most significant difference was excessive nonspecific staining consistently seen with the MBA-2 conjugate. Overall, Flow-2 and MBA-bivalent antisera were preferable.

Antibodies, Viral↗
PubMed1976

Haemophilus paraphrophilus endocarditis in a prolapsed mitral valve.

A case of Haemophilus paraphrophilus endocarditis successfully treated with ampicillin is described. The patient, a 24-year-old woman, had a prolapsed mitral valve. The organism was initally misidentified as H. parainfluenzae, which it closely resembles. H. paraphrophilus is distinguished by its requirement of 10% CO2 for growth on NaCl-free medium and its inability to ferment xylose.

Adult↗
PubMed1976

Combined serotyping and biotyping of Serratia marcescens.

The API (Analytab Products, Inc., New York, N.Y.) biotypes of 117 clinical isolates of Serratia marcescens were determined and fell into 13 different patterns. The O and H antigens were determined by tube agglutination, and 27 serotypes were identified. The biotype and serotype appeared to vary indepently. Serotyping and biotyping combined divided these isolates into 56 different types. There was a problem interpreting the end points for inositol fermentation and urease production, which could affect reproducibility of API biotypes. Biotyping is a simple way of screening for possible nosocomial outbreaks of S. marcescens.

Bacterial Infections↗
PubMed1973

Direct immunofluorescence test for the diagnosis of genital herpesvirus infections.

Herpetic lesions of the genitalia may be confused clinically with other ulcerative, genital lesions. Direct immunofluorescence (FA) provides a rapid method of diagnosis, and the utility of this method for the diagnosis of genital ulcers was examined. One hundred and ten patients with genital lesions were examined by darkfield for syphilis and by FA and culture for herpes simplex virus (HSV) infections. Satisfactory samples were obtained from 102 patients, of which 81 were clinically suspected cases of HSV. Acetone-fixed slides of scrapings of ulcerative lesions were stained with conjugated antiserum prepared in rabbits against HSV type 2. HSV was isolated from 73% of specimens of suspected herpetic lesions, and 77% of these specimens were positive by FA. Nine percent were positive by FA only and these were not thought to represent false positives. Five percent were positive by culture only. A comparison of clinical diagnoses with laboratory findings revealed that 4% of the cases were misdiagnosed when only the clinical evaluation was considered. The data suggest that the inclusion of a diagnostic FA test for HSV along with the darkfield examination may be useful for differentiating the etiological agents of ulcerative, genital lesions.

Adolescent↗
PubMed1971

Effects of the recipient strain and ultraviolet irradiation on transduction kinetics of the penicillinase plasmid of Staphylococcus aureus.

When the penicillinase plasmid of Staphylococcus aureus PS 81(P(81))(T(81)) was transferred to its cured derivative of PS 81(N(P))(T(81)), there was a fivefold increase in the transduction frequency of penicillinase plasmid markers after ultraviolet (UV) irradiation of the phage instead of the expected decrease typical for plasmid-borne markers. These results were independent of the transducing phage, the donor, and the method of curing the recipient and were also obtained with a cured derivative of PS 80(PI(80)). With PS 52, a naturally occurring penicillin-sensitive strain, and a cured transductant of PS 52 as the recipients, typical plasmid kinetics were observed. The plasmid location of penicillinase plasmid markers in transductants was confirmed by their instability in ethidium bromide (EB). In a cross between isogenic plasmids (PI(258)penZ cad x PI(258)penI asa ero), transductants were doubly selected for cadmium and erythromycin resistances. There was a twofold increase in transduction frequency after UV irradiation of the transducing phage and an increase in the proportion of recombinant type transductants. CsCl-EB density centrifugation revealed that plasmid deoxyribonucleic acid (DNA) was present in PS 81(P(81))(N(T)) and its cured derivative [PS 81(N(P))(N(T))], but not in PS 52. Sucrose gradient analysis of plasmid DNA showed that the penicillinase plasmid of PS 81(P(81))(N(T)) was larger than the plasmid in its cured derivative. Thus, the cured derivative contains plasmid DNA which appears to recombine with the incoming plasmid, causing the rise in transduction frequency noted after UV irradiation of transducing phage.

Arsenic↗
PubMed1971

Effects of ethidium bromide on growth and on loss of the penicillinase plasmid of Staphylococcus aureus.

Ethidium bromide (EB) was more efficient than ethyl violet or rifampin as a curing agent for the penicillinase plasmids of Staphylococcus aureus strains. The effects of EB on growth and on the loss of the penicillinase plasmid of PS 81 were studied in detail. The growth rates of PS 81 and an EB-cured derivative were identical in broth, but the cured derivative had a shorter lag in the presence of added 6 x 10(-6)m EB. The shortened lag was due to prior exposure to EB as the cured derivative and an EB-treated but uncured strain of PS 81 gave identical growth lag and growth rates in the presence of EB. The curing of PS 81 by EB occurs in three phases. After a 4 to 5 hr lag, there is a 100-fold increase in the number of penicillinase-negative cells, and the proportion of cured cells continues to rise until 10 to 12 hr. Thereafter, the population becomes refractory to further curing, and the proportion of penicillinase-negative cells remains constant at about 20% of the total. Penicillinase-positive survivors of EB treatment showed increased EB resistance and were cured at lower rates upon subsequent EB treatment. Isolated colonies of the parental strain PS 81 were heterogeneous in their EB sensitivity. Thus, EB does not competitively favor spontaneously cured penicillinase-negative cells but appears to act in a manner analogous to acridine orange on the plasmids of enteric bacteria.

Coloring Agents↗
PubMedDate not supplied

Magnetic resonance imaging of muscle injury.

To further evaluate the role of magnetic resonance (MR) imaging in diagnosing and managing muscle injuries, eight patients with muscle pain or palpable masses were imaged. MR findings were correlated with clinical follow-up data. Increased signal was noted on T2-weighted images in torn and overused muscles. One extensively scarred muscle required surgical biopsy to exclude a fibrous tumor. Three partial muscle tears were treated conservatively. One complete musculotendinous junction tear required tendon transfer. MR studies noninvasively identified and staged various muscle injuries, thereby influencing management.

Adult↗
PubMedDate not supplied

Evaluation of the buffy-coat smear for rapid detection of bacteremia.

Buffy-coat smears prepared from 599 blood samples, obtained simultaneously with blood for culture, were examined for bacteria. Each blood sample was quantitatively cultured on chocolate agar. Twenty-one blood cultures (3.6%) from 17 patients were positive. Two (11.7%) of the 17 patients had positive buffy-coat smears. One patient had two positive smears, for a total of three positive buffy-coat smears from 21 positive blood cultures. Chart reviews were performed for two patients with positive buffy-coat smears, three patients with positive blood cultures (containing the same organisms as the two study patients) but negative buffy-coat smears, and six additional patients who had had positive buffy-coat smears between 1974 and 1979. Of the eight patients with positive smears, six (75%) were infected with Gram-positive cocci, three of which were Streptococcus pneumoniae. Mortality was 100%.

Adult↗
PubMedDate not supplied

Diagnostic virology laboratory within a microbiology setting.

The virology section at St. Francis Hospital and Medical Center, Connecticut, is not a separate laboratory division but is a part of the microbiology division and is supervised by the same personnel who supervise bacteriology, mycology, mycobacteriology, and serology. Current volume is over 1,000 cultures yearly with 12 to 24 percent positive. Isolates are confirmed and typed by the Connecticut State Health Department Laboratory. Specimen distribution, percentage positive specimens, and distribution of viral isolates are similar to those reported from microbiology laboratories with separate virology laboratories directed by a full-time doctoral-level virologist. Our seven years' experience demonstrates that a microbiology laboratory without a full-time doctoral-level virologist can provide clinically useful virologic information.

Hospitals, Community↗
PubMedDate not supplied

Phase I dose-escalation study of tumor necrosis factor-alpha and concomitant radiation therapy.

PURPOSE: Tumor necrosis factor-alpha enhances x-ray killing of human tumor cells in vitro and enhances tumor control when combined with radiation in animal tumor models. To determine the toxicity and maximal tolerated dose of tumor necrosis factor-alpha given daily during radiotherapy, we conducted a phase I dose-escalation study combining tumor necrosis factor-alpha and radiation. PATIENTS AND METHODS: Thirty-one patients, including 14 patients with locally advanced primary tumors and 17 patients with metastatic sites, were entered into this study. Recombinant human tumor necrosis factor-alpha was administered intravenously at doses ranging from 10 microg/m2 to 150 microg/m2 4 hours prior to each radiation therapy session, which was given on consecutive days for a minimum of 2 weeks. Radiation was prescribed to localized fields, with dose fractions ranging from 150 to 300 cGy/day for palliation or control of locally advanced tumors. RESULTS: Major toxicity requiring withdrawal from the study was independent of tumor necrosis factor-alpha dose and occurred in seven patients. Symptoms included angina in two patients, and hypotension, respiratory distress, atrial fibrillation, allergic reaction, and progressive leukopenia in one patient each. A tumor necrosis factor-alpha dose of 150 microg/m2 was the maximum dose administered. No single dose-limiting toxicity was observed and a maximal tolerated dose could not be defined. There was no obvious increase in in-field toxicity. Response to treatment was assessed in 20 patients. Complete regression within the irradiated field was achieved in four patients, partial regression in four, and a minimal response in four. A trend toward a greater response rate at higher doses of tumor necrosis factor-alpha was observed. CONCLUSIONS: The maximal tolerated dose of tumor necrosis factor-alpha when given with radiotherapy is at least 150 microg/m2 and a dose-limiting toxicity was not observed. Future studies will show whether responses to treatment are increased over those expected with radiation alone. Tumor localization of tumor necrosis factor-alpha by gene therapy combined with radiation therapy may eliminate the systemic toxicity we observed.

Adult↗