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Biomedical subjects

S J Rubin

Publications and source records attributed to S J Rubin.

At least 37 records · Page 2Linked to original sources

Magnetic resonance grid analysis of soft tissue lesions.

Soft tissue tumors of seven patients were imaged with magnetic resonance imaging (MRI) prior to operative resection. In four cases, gross surgical specimen biopsy sites were broadly selected from areas of diverse signal intensity. A subsequently developed "grid analysis" technique, used in three additional patients, better localized differing zonal intensities within individual gross specimens. Further investigation of this technique is warranted, since MR images, when analyzed by means of a detailed grid technique, appear to enhance histologic diagnostic accuracy. Examination of larger segments of inhomogeneous soft tissue tumors is facilitated, while pathologists' sampling time is diminished.

Adult↗

Preoperative radiotherapy followed by radical vulvectomy with inguinal lymphadenectomy for advanced vulvar carcinomas.

A therapeutic alternative to exenteration for large locally advanced vulvar carcinoma involving the rectum, anus, or vagina is the use of preoperative radiation followed by radical surgery. Between 1980 and 1988, 13 patients with Stage III and 3 with Stage IV vulvar carcinoma involving the rectum/anus, urethra, or vagina were treated with 4000 rad to the vulva and 4500 rad to the inguinal and pelvic nodes followed by a radical vulvectomy and inguinal lymphadenectomy 4 weeks later. The overall 5 year cumulative survival was 45%. Twelve tumors regressed after radiation with 62.5% of the patients having visceral preservation while in 4 patients there was no major response to radiation and urinary or fecal diversion was required. Of the 6 recurrences 4 were central and 2 distant. Three patients with central recurrences had tumor within 1 cm of the vulvectomy margin. Complications included wet desquamation, inguinal wound separation, lymphedema, and urethral strictures. There were no operative deaths. It is concluded that the use of preoperative radiation followed by radical vulvectomy may be an alternative to pelvic exenteration in selected patients with advanced vulvar lesions.

Adult↗

GABAergic and cholinergic neurons exhibit high-affinity nerve growth factor binding in rat basal forebrain.

We have used dissociated, rat basal forebrain cultures to identify specific cell types that are potentially responsive to nerve growth factor (NGF). Expression of high-affinity NGF binding sites was examined. A subpopulation of cells containing choline acetyltransferase (CAT), the acetylcholine-synthesizing enzyme, exhibited high-affinity binding, employing combined immunocytochemistry and 125I-NGF radioautography. Unexpectedly, a gamma-aminobutyric acid (GABA)-containing cell group also expressed high-affinity binding. These cells that exhibit high-affinity binding appear to be neurons since they stain positively with the neuron marker, neuron-specific enolase, and negatively with the nonneuron marker, glial fibrillary acidic protein. Our observations suggest that NGF may regulate multiple brain systems and functions that have yet to be explored. Conversely, only subsets of cholinergic or GABA neurons expressed high-affinity binding, suggesting that these transmitter populations are composed of differentially responsive subpopulations.

Animals↗

Comparison of commercial sources of primary rabbit kidney and MRC-5 cell cultures for herpes simplex virus isolation.

Two commercial sources of MRC-5 and primary rabbit kidney cell cultures were compared for sensitivity of herpes simplex virus isolation and cytopathic effect detection time. Forty-six of 78 previously positive and 50 of 234 fresh clinical specimens were positive and could be evaluated. Herpes simplex virus recovery from frozen specimens positive in at least one cell culture ranged from 85% in MRC-5 cells (M.A. Bioproducts) to 89% in primary rabbit kidney cells (M.A. Bioproducts). Herpes simplex virus recovery from fresh clinical specimens ranged from 94% in primary rabbit kidney cells (Flow Laboratories), MRC-5 cells (Flow Laboratories), and MRC-5 (M.A. Bioproducts) cells to 100% in primary rabbit kidney (M.A. Bioproducts) cells. Among the 96 positive specimens evaluated, no significant difference was found between commercially prepared MRC-5 and primary rabbit kidney cell cultures in either sensitivity or time to first detectable cytopathic effect. Cells from M.A. Bioproducts and Flow Laboratories were equally sensitive. Herpes simplex virus detection was dependent upon inoculating at least two cell culture tubes rather than if the cells were MRC-5 cells or primary rabbit kidney cells.

Animals↗

Klebsiella marker systems.

Klebsiella marker systems include determination of susceptibility patterns, serotype, bacteriocin susceptibility, bacteriophage susceptibility, biotype, and plasmid content, size and endonuclease fragment size. Susceptibility patterns are useful only if unusual patterns (ie, aminoglycoside resistance) occur. Serotypes are stable, reproducible markers. Over 90% of isolates can be serotyped and epidemiologically unrelated strains are widely distributed among the 72 standard types. Antisera are not available commercially except to types 1 to 6 and serotyping is expensive and time-consuming. Bacteriocin susceptibility typing is easier and cheaper but reproducibility is sometimes poor. Depending on the producer strains used, between 67% and 96% of strains are typable. As a single typing method, bacteriophage typing is not very sensitive. Only 70% of strains are typable and 20% are of a single type. There are two major problems with most biotyping systems: poor reproducibility and poor sensitivity. A high percent of strains is the same type. Plasmid analysis is technically the most complicated but is important if strains are aminoglycoside resistant. No one method is ideal, and characterization of isolates from an outbreak is best done by using several different marker systems.

Anti-Bacterial Agents↗

DF-2: a fastidious fermentative gram-negative rod.

Current information is reviewed from 26 cases of human infection by DF-2, a fastidious gram-negative rod. These infections are typically associated with dog contact or dog bites. Underlying diseases or prior splenectomy are predisposing factors for severe infection with a potentially fatal outcome. The methods for isolating and identifying the microorganism are given. Long, thin, slowly growing, oxidase-positive, catalase-positive gram-negative rods that do not grow on MacConkey agar should suggest DF-2. Although testing of antimicrobial susceptibility is problematic, DF-2 has been found to be resistant to aminoglycosides. The drug of choice is penicillin.

Adolescent↗

Comparison of Cultureset and primary rabbit kidney cell culture for the detection of herpes simplex virus.

Herpes simplex virus isolation by conventional cell culture in primary rabbit kidney cells (RK) was compared with Cultureset (CS). At 24 h CS was more sensitive (31 versus 25 of 55 isolates detected) than RK, but at 48 h there was little difference (43 detected by CS, 46 by RK). CS stained at 48 h was significantly less sensitive (78.2%) than RK observed for 1 week. CS stained at 24 or 48 h was not an acceptable substitute for RK observed for 1 week.

Animals↗

Detection of viruses in spinal fluid.

Among the confirmed cases of viral meningitis and encephalitis, the most commonly diagnosed agents are enteroviruses, arboviruses, and herpes simplex virus. Definitive diagnosis of a viral infection often affects patient management, length of hospitalization, and antibiotic use. Laboratory diagnostic methods include microscopic examination of clinical specimens, virus culture, serologic studies, and immunologic detection of virus or viral antigens. Microscopic examination of cerebrospinal fluid is nonproductive, and, except for enteroviruses, culture almost always gives negative results. Viral culture of the cerebrospinal fluid, throat, and feces is the diagnostic method of choice for enteroviruses. Definitive diagnosis of herpes simplex virus encephalitis must be based on virus isolation from brain biopsy material. Arbovirus infection is diagnosed serologically. Although none of the newer rapid immunologic techniques is commercially available, some do hold great promise. These include measurement of virus-specific immunoglobulin M (IgM) and detection of viral antigens by enzyme or radioimmunoassay. A sensitive and specific procedure for early detection of herpes simplex virus antigens in cerebrospinal fluid would be of great benefit.

Antibodies, Viral↗

Enhanced isolation of Campylobacter jejuni by cold enrichment in Campy-thio broth.

Isolation of Campylobacter jejuni from human feces by direct inoculation to Campy-BAP (Scott Laboratories, Inc., Fiskeville, R.I.) was compared with isolation after overnight enrichment at 4 degrees C in Campy-thio broth followed by subculture to Campy-BAP. Of 54 positive specimens, 19 were positive only after enrichment, and 5 were positive only on the direct plate. Among 36 positive patients, 10 were detected by enrichment only and 2 by direct plating only. Laboratories using Campy-BAP should include cold enrichment in Campy-thio broth for optimum recovery of C. jejuni.

Campylobacter fetus↗

Clinical significance of viridans streptococci isolated from blood cultures.

The clinical significance of viridans streptococci isolated from the blood cultures of 86 patients was determined. Isolates that were significant or suggestive of infection represented only 21% of the cases. Among 54 isolates for which the species was known, Streptococcus sanguis II was the most common. However, a significant association between species and clinical significance was not found.

Blood↗

Mucosal invasion in campylobacter enteritis.

Campylobacter fetus subspecies jejuni has recently been recognized as a significant cause of enteritis in humans. The organism has been previously postulated to cause illness by direct invasion of the mucosa of the gastrointestinal tract, but this has not been documented. Reported is a case of Campylobacter enteritis in which mucosal ulceration and crypt sbscesses were seen on rectal biopsy, suggesting that the pathogenesis of Campylobacter fetus enteritis involves direct mucosal invasion.

Adolescent↗

Seroepidemiology of clinical isolates of Klebsiella in Connecticut.

The distribution of capsular serotypes of 200 clinical isolates of Klebsiella pneumoniae and Klebsiella oxytoca from four Connecticut hospitals was determined. Serotyping was done by an indirect fluorescent-antibody technique. Hospitals included three community hospitals from the Hartford area and one university hospital in New Haven. During the test period, epidemiological surveillance did not detect any nosocomial epidemic involving Klebsiella species. Ninety-two percent of the isolates were typable. Of the 72 possible serotypes, 62 were represented among these strains. Forty-two percent of the typable strains were distributed among 10 serotypes. The predominant serotypes were types 31, 22, and 18 representing 19% of the typable strains (8, 6, and 5%, respectively). No one particular serotype was associated exclusively with a specific site of infection.

Blood↗

Isolation of Leptospira biflexa from commercially prepared deionized water labeled "sterile for tissue culture".

Leptospira biflexa were isolated from urine cultures of two patients with clinical and laboratory findings compatible with leptospirosis. Neither patient had detectable leptospiral agglutinins. The source of the L. biflexa was water labeled " "sterile for tissue culture" purchased from M. A. Bioproducts, formerly Microbological Associates. M. A. Bioproducts water is sterilized by filtration through a 0.22-mum-pore size membrane filter. Leptospiral contamination can occur in products sterilized by filtration. Heat sterilization of water eliminates this possibility.

Adult↗

Reproducibility of an indirect immunofluorescent-antibody technique for capsular serotyping of Klebsiella pneumoniae.

Reproducibility of capsular serotypes of 55 consecutive clinical isolates of Klebsiella pneumoniae was evaluated by an indirect immunofluorescent-antibody technique previously described by Riser et al. (J. Clin. Pathol. 29: 296-304, 1976) Five colonies per specimen were examined for colony-to-colony variation, day-to-day variation, and reader-to-reader variation. Seventy-two reference strains were tested with each of 18 pools and 72 specific antisera prior to the clinical specimens to determine antiserum specificity and cross-reaction patterns. Lot-to-lot variation was examined with the reference strains. There was minimal lot-to-lot variation among the antisera tested. Ten antiserum pools required supplementation with individual antisera. The patterns of supplementation may vary from lot to lot. Colony-to-colony variation in intensity of immunofluorescence occurred, but there was no variation in serotype. These findings differ from previously reported colonial variation which occurred when API 20E biotypes were determined for individual colonies of K. pneumoniae directly from clinical specimens. Eighteen percent of clinical isolates studied gave cross-reactions when tested with the indicated specific antiserum. All but one of the cross-reactions were resolved with further dilutions. Day-to-day and reader-to-reader variations were minimal. The immunofluorescent-antibody technique is a reliable and reproducible method for capsular serotype determination. Capsular serotypes are less variable than API biotypes since colony-to-colony variation of serotype does not occur.

Cross Reactions↗

Pseudobacteremia: false-positive blood cultures from mist tent contamination.

In the seven-month period from July 1975 through January 1976, 11 pediatric patients had Acinetobacter calcoaceticus var. anitratus cultured from blood; this organism had not been isolated from pediatric patients in the previous six months. In 10 of 11 patients, only the first of two cultures was positive. All patients recovered uneventfully, although only two were treated with appropriate antibiotics. Nine of 11 had been in mist tents at the time of the culture. Mist cultured from one tent contained the same organism found in the patient's blood culture. Eight of 10 patients, however, had blood for culture drawn from the same needle as samples for other blood work, compared with only three of 13 controls (p = .013); this represented a deviation from proper blood culture technique, and a mock trial confirmed contamination of blood cultures when technique was broken. Contamination by this organism occurred in the tent water reservoir and mist, and the nose and skin of the children were colonized. The hands of respiratory therapy technicians and blood-drawing personnel became contaminated while handling the mist tents. Thorough attention to hand-washing, tent sterilization, and technique in drawing blood cultures stopped the pseudo-epidemic.

Acinetobacter↗

Multiple biotypes of Klebsiella pneumoniae in single clinical specimens.

The occurence of multiple biotypes of Klebsiella pneumoniae within single specimens was determined in 59 clinical specimens. Biotyping was performed on five colonies of K. pneumoniae from each specimen, using the API 20E system (Analytab, Inc., New York) for identification of Enterobacteriaceae with strict adherence to the manufacturer's instructions. Multiple biotypes of K. pneumoniae were present in 31% (18) of the clinical specimens. Twenty-eight colonies representative of specimens with single and multiple biotypes were tested further for biotype reproducibility. Whereas genus and species identification was 100% reproducible, variation of one or more biochemical tests on serial transfers resulted in biotype reproducibility of only 64%. The greatest variation in biochemical tests occurred with urease (14%), indole production (10%) and citrate utilization (9%). Multiple biotypes in single specimens appear to be due to both inherent differences among the colonies in the specimen and variability in the system used to determine biochemical reactions. The presence of multiple biotypes limits the usefulness of biochemical typing for epidemiological surveilance of K. pneumoniae.

Humans↗