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Biomedical subjects

E L Kaplan

Publications and source records attributed to E L Kaplan.

At least 19 recordsLinked to original sources
PubMed1998

Ethnic differences in expression of susceptibility marker(s) in rheumatic fever/rheumatic heart disease patients.

The ability of monoclonal antibodies (MAb) against a human B lymphocyte alloantigen has been suggested to discriminate between rheumatic fever "susceptible" individuals and persons with a lower risk of developing RF. However, while such MAb have been reported to identify a majority of RF/RHD patients in some populations, a reduced discriminatory ability has been observed in others. Antigenic variation in the RF marker(s) may exist among ethnic groups which reduce the discriminatory ability of these monoclonal antibodies. We developed MAb using B lymphocytes from RF patients of North Indian ethnic origin. In this same population we compared the new MAb (PGI/MN II) with a previously described MAb of Caucasian ethnic origin (D8/17). In three groups: acute rheumatic fever patients (no evidence of previous attacks of rheumatic fever), patients with chronic rheumatic heart disease and normal controls from the same population, we found a greater discriminating ability of PGI/MNII MAb to identify Indian RF/RHD patients than with the D8/17 MAb. Further, sixty percent of 142 siblings of the RF/RHD patients were "positive" when tested with PGI/MN II. The data from these studies suggest that before such MAb can be used for identification of RF "susceptibles" in public health programs, variation among ethnic populations must be assessed.

Adolescent↗
PubMed1998

Why have group A streptococci remained susceptible to penicillin? Report on a symposium.

In spite of 50 years of extensive use of penicillin, group A streptococci remain exquisitely susceptible to this antibiotic. This observation that continuing susceptibility has occurred despite the development of resistance to other antimicrobial agents prompted a day-long meeting at Rockefeller University (New York) in October 1996. Among the most likely explanations for this remarkable state of continued susceptibility to penicillin are that beta-lactamase may not be expressed or may be toxic to the organism and/or that low-affinity penicillin-binding proteins either are not expressed or render organisms nonviable. Other potential explanations are that circumstances favorable for the development of resistance have not yet occurred and/or that there are inefficient mechanisms for or barriers to genetic transfer. Recommended future actions include (1) additional laboratory investigations of gene transfer, penicillin-binding proteins, virulence factors, and homeologous recombination and mismatch repair; (2) increased surveillance for the development of penicillin resistance; (3) application of bioinformatics to analyze streptococcal genome sequences; and (4) development of vaccines and novel antimicrobial agents. Thus far the susceptibility of group A streptococci to penicillin has not been a major clinical or epidemiological problem. A similar observation, however, could have been made decades ago about Streptococcus pneumoniae. It is therefore vital for the scientific community to closely examine why penicillin has remained uniformly highly active against group A streptococci in order to maintain this desirable state.

Humans↗
PubMed1998

Studies of the continuing susceptibility of group A streptococcal strains to penicillin during eight decades.

BACKGROUND: In view of the widespread use of penicillin for >50 years for the treatment of group A streptococcal infections, we examined the question of whether there has been a change in susceptibility to penicillin in group A streptococcal strains collected during a span of 80 years (1917 to 1997). METHODS: One hundred thirty-three group A streptococcal strains collected during 80 years were tested for changes in penicillin susceptibility. Three tests were used: (1) the microtiter broth minimal inhibitory concentration (MIC); (2) the minimal bactericidal concentration (MBC); and (3) the penicillin E strip MIC. RESULTS: The results indicate there has been no change in the susceptibility to penicillin in these group A streptococci during the past 80 years. The microtiter broth MIC90 for the oldest strains (0.032 microg/ml) was not significantly different from those collected most recently (0.032 microg/ml); there is no statistical difference between the raw MIC data for the four collection periods (P=0.468, analysis of variance on ranks). CONCLUSIONS: There has been no change in the susceptibility of group A streptococci during this time in spite of well-documented cases of penicillin resistance in other Gram-positive organisms and despite recognized resistance of group A streptococci to other antibiotics.

Anti-Bacterial Agents↗
PubMed1998

Antistreptolysin O and anti-deoxyribonuclease B titers: normal values for children ages 2 to 12 in the United States.

BACKGROUND: Measurement of antibodies to the extracellular antigens produced by group A streptococci, antistreptolysin O (ASO) and anti-deoxyribonuclease B (anti-DNase B), is often necessary to confirm a clinical diagnosis of a previous group A streptococcal infection, especially in patients suspected of having a nonsuppurative sequel to this infection. Age is among several factors that may influence antibody levels in children. Thus, in contrast to adults, what is considered a normal titer for one age group (infants) is not appropriate for another (older children). Age-related "normal" values for ASO and anti-DNase B are provided in the package inserts of commercially available kits; however, there are no recent comprehensive data to validate such values. OBJECTIVE: Using sera from 1131 children (from 23 states) ages 2 to 12 years, we determined age-specific geometric mean titers (GMT) and upper limits of normal (ULN) of ASO and anti-DNase B. METHODS: ASO and anti-DNase B titers were measured by conventional laboratory methods. RESULTS: Children 7 years of age comprised the largest proportion (14%) of the study population. Approximately two-thirds of the sera were collected during winter and early spring months. For both ASO and anti-DNase B, both GMT values and ULN increased with age. The GMTs for ASO and anti-DNase B for the entire group of subjects were 89 and 112, respectively. The ULN for the entire group for ASO and anti-DNase B were 240 and 640, respectively. CONCLUSION: The age-specific values for GMT and ULN for this group of children from 23 states were slightly higher than previously reported. These values are likely representative of the pediatric population in the United States and should be of clinical value to physicians, epidemiologists, and clinical laboratory personnel.

Age Factors↗
PubMed1997

The presence of K-12 ras mutations in duodenal adenocarcinomas and the absence of ras mutations in other small bowel adenocarcinomas and carcinoid tumors.

BACKGROUND: Adenocarcinomas and carcinoid tumors are the most common malignant tumors of the small intestine. K-ras oncogene mutations at codon 12 are common in gastric, pancreatic, and colon carcinomas, with an incidence of 35-88%. K-ras mutations have not been extensively studied in either adenocarcinomas or carcinoid tumors of the small bowel. The purpose of this study was to determine whether ras mutations play an important role in the formation of these tumors. METHODS: Archival tissues from 28 adenocarcinomas and 22 carcinoid tumors of the small bowel were studied, along with archival tissues from 32 adenocarcinomas of the large bowel, which were used as controls. DNA from the small intestine tumors was analyzed for K-ras, H-ras, and N-ras oncogene mutations at codons 12, 13, and 61, using polymerase chain reaction and sequence specific oligonucleotide hybridization techniques. Large bowel adenocarcinomas were analyzed for K-ras mutations at codons 12 and 13. RESULTS: A point mutation of K-ras at codon 12 was detected in 4 of 28 (14.3%) of the small bowel adenocarcinomas, in 12 of 32 (37.5%) of the large bowel adenocarcinomas, and in 0 of 22 small intestine carcinoid tumors. No other K-ras, H-ras, or N-ras mutations were detected in any of the small bowel tumors. Each small intestine K-ras mutation was found in a duodenal adenocarcinoma (4 of 12 cases, 33%), whereas none occurred in 16 other jejunal or ileal adenocarcinomas. CONCLUSIONS: K-ras mutations appear to play a significant role in the pathogenesis of duodenal adenocarcinomas, but they do not appear to be important in the development of jejunal or ileal adenocarcinomas or of carcinoid tumors of the small intestine.

Adenocarcinoma↗
PubMed1997

Optical immunoassay test for group A beta-hemolytic streptococcal pharyngitis. An office-based, multicenter investigation.

OBJECTIVE: To compare the accuracy of an optical immunoassay (OIA) for the rapid diagnosis of group A streptococcal pharyngitis with blood agar plate (BAP) culture. DESIGN: Blinded comparison with criterion standard. SETTING: A total of 6 private pediatricians' offices, 3 in Connecticut and 3 in Chicago, III. PATIENTS: A total of 2113 consecutive patients with acute pharyngitis, 983 in Connecticut and 1130 in Chicago. MAIN OUTCOME MEASURES: The sensitivities and specificities of OIA and BAP culture (both performed and interpreted in the office) were determined using a research laboratory's interpretation of a combination of BAP culture and Todd-Hewitt broth (THB) culture of transport tube pledget as criterion standard. RESULTS: Among patients in Connecticut, the sensitivities of the OIA and BAP culture were 94% and 89%, respectively (P=.004), while the specificities were 96% and 99%, respectively (P=.001). Among patients in Chicago, the sensitivities of the OIA and BAP culture were 79% and 72%, respectively (P<.001), while the specificities were 89% and 99%, respectively (P<.001). In each of the 6 pediatricians' offices, the OIA was more sensitive than the BAP culture. Combining the data from Connecticut and Chicago, the overall sensitivities of the OIA and BAP culture were 84% and 78%, respectively (P<.001), while the specificities were 93% and 99%, respectively (P<.001). CONCLUSIONS: The results of this comprehensive office-based investigation suggest that with adequately trained personnel, negative OIA test results may not always need to be routinely confirmed with BAP cultures.

Acute Disease↗
PubMed1997

Familial transmission of a serious disease--producing group A streptococcus clone: case reports and review.

Invasive group A streptococcus (GAS) infections are emerging diseases; however, person-to-person transmission of invasive GAS producing life-threatening infection has been observed rarely. We report a small intrafamilial cluster of life-threatening GAS infections. A previously healthy 47-year-old father developed necrotizing fasciitis of the neck. Two days later, his 16-year-old daughter developed streptococcal angina, pneumonia, and pleural empyema. Both patients had signs of streptococcal toxic shock syndrome. Pulsed field gel electrophoresis revealed that the M6 strains of GAS isolated from the father and daughter had identical patterns. Cases of person-to-person transmission of invasive GAS infection reported in the literature are also reviewed.

Adolescent↗
PubMed1997

Diagnosis and management of group A streptococcal pharyngitis: a practice guideline. Infectious Diseases Society of America.

This is the second in a series of practice guidelines commissioned by the Infectious Diseases Society of America through its Practice Guidelines Committee. The purpose of these guidelines is to provide assistance to clinicians when making decisions on treating the conditions specified in each guideline. The targeted providers are pediatricians, family practitioners, and internists. The targeted patients and setting for the acute pharyngitis guideline are pediatric, adolescent, and adult outpatients with a complaint of sore throat. Funding was provided by the IDSA. Panel members represented experts in adult and pediatric infectious diseases. The guidelines are evidence-based. A standard ranking system was used for the strength of the recommendations and the quality of the evidence cited in the literature reviewed. The document has been subjected to external review by peer reviewers as well as by the Practice Guidelines Committee and was approved by the IDSA Council. An executive summary, algorithms, and tables highlight the major recommendations. Indicators of quality will assist in guideline implementation. The guideline will be listed on the IDSA home page at http://www.idsociety.org.

Adolescent↗
PubMed1997

Invasive group A streptococcal infections in North Carolina: epidemiology, clinical features, and genetic and serotype analysis of causative organisms.

During 1994 and 1995, an increase in the number and severity of group A streptococcal (GAS) infections was noted in North Carolina. Ninety-six patients had GAS recovered from blood and other sterile body fluids, abscesses, and soft tissue. The overall case fatality rate was 11% but was much higher in patients with toxic shock syndrome (55%) and necrotizing fasciitis (58%). Recent invasive GAS isolates were compared with pre-1994 invasive isolates and temporally related pharyngeal isolates by M protein serotyping, pulsed field gel electrophoresis (PFGE), and polymerase chain reaction amplification of the streptococcal pyrogenic exotoxin A gene. Serotypes M1 and M3 accounted for 50% of recent invasive isolates (1994-1995) and 58% of pharyngeal isolates (1994). The latter isolates demonstrated PFGE patterns that were identical to invasive M1 and M3 strains, suggesting that pharyngeal infections may have served as a reservoir for virulent GAS clones.

Abscess↗
PubMed1997

Recent evaluation of antimicrobial resistance in beta-hemolytic streptococci.

Although antimicrobial resistance among bacteria continues to increase and to be a clinical problem, the beta-hemolytic streptococci have remained remarkably susceptible to most antibiotics. For example, there has not been a single documented instance of a clinical isolate of a penicillin-resistant group A streptococcus. Moreover, available data indicate that the minimal inhibitory concentrations (MICs) of penicillin for group A streptococci have not changed during the past 4, decades. In one study, the MIC90 for more than 300 strains of group A streptococci was only 0.012 microgram/mL. Resistance to the macrolide antibiotics, the tetracyclines, and the sulfa drugs remains more clinically important. Outbreaks of macrolide resistance have been documented in several parts of the world, but macrolide resistance in most countries of the world remains at < 5% among group A streptococci. Despite the fact that clinically significant antibiotic resistance has not emerged, careful surveillance is required.

Drug Resistance, Microbial↗
PubMed1997

Serotypes of group A streptococci isolated from healthy schoolchildren in the United Arab Emirates.

Group A streptococci (GAS) are the most frequent cause of pharyngitis in children and are a common cause of emergency room or paediatric clinic visits worldwide. This study determined the representative M and T types of GAS, and their distribution, among schoolchildren in the United Arab Emirates. Throat swabs were taken and cultured for GAS isolates during the winter of 1994-95 from 1000 children aged 5-7 years attending nine schools. Of the isolates obtained, 100 were serotyped using standard techniques. Nearly all these isolates (91%) were T typable, falling into 15 T types; the commonest being type 1 (n = 17), type 6 (n = 15), type 11 (n = 10), type 2 (n = 8), type 12 (n = 8), and type 28 (n = 8). A total of 76% of the isolates were typable for M protein, falling into 14 M types, with type 1 (n = 17), type 6 (n = 15), type 2 (n = 8), type 22 (n = 5), type 28 (n = 7), and type 75 (n = 5) predominating. Serotype clusters were found in certain classes or schools, although the number of isolates examined was too small to allow definitive epidemiological conclusions to be drawn. The ease of serotyping these isolates suggests that GAS strains in the United Arab Emirates are similar, but not necessarily related, to those commonly found in the USA and Europe, and that these may be the most prevalent strains worldwide. The relative prevalence of M type 1 is significant, as this GAS serotype is associated with serious diseases such as rheumatic heart disease, a recognized problem in the United Arab Emirates, and toxic shock syndrome, which has not yet been reported from this area. Knowledge of the prevalence of GAS serotypes, and further research on the epidemiology of streptococcal disease, will be useful should streptococcal vaccines become available.

Age Factors↗