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Biomedical subjects

R A Feldman

Publications and source records attributed to R A Feldman.

At least 109 records · Page 6Linked to original sources
PubMed1981

Epidemiologic characteristics of necrotizing enterocolitis: a population-based study.

The authors studied retrospectively the epidemiologic characteristics of necrotizing enterocolitis occurring among Georgia infants born during 1977 and 1978; 148 cases of necrotizing enterocolitis were identified. The highest incidence rate for necrotizing enterocolitis occurred among infants weighing 751-1000 g at birth and declined with increasing birth weight to less than 0.2 cases per 1000 live births among infants weighing more than 2500 g at birth. The overall incidence rate for blacks was significantly greater than that for whites (1.6 vs. 0.5 cases per 1000 live births, p = 0.01). The overall case fatality ratio was 38.5%; there were no differences in these ratios between blacks and whites. Necrotizing enterocolitis accounted for 15% of all deaths after the first week of life for infants weighting 1500 g or less at birth. If Georgia incidence rates and fatality ratios are applied to 1978 US births, it is estimated that 2210 cases of necrotizing enterocolitis with over 900 associated deaths would have occurred.

Birth Weight↗
PubMed1981

Mutants of Fujinami sarcoma virus which are temperature sensitive for cellular transformation and protein kinase activity.

Two temperature-sensitive mutants of Fujinami sarcoma virus were isolated and characterized. Cells infected with the mutants were temperature sensitive in focus formation, colony formation, increased sugar uptake, and synthesis of plasminogen activator. The changes between transformed and nontransformed states of cultures were completely reversible by shifting the temperature. A Fujinami sarcoma virus-specific protein of 130,000 daltons, p130, was synthesized in mutant-infected cells regardless of the temperature, but the immunoprecipitates of p130 from extracts of infected cells were active in protein kinase only when cells had been incubated at the permissive temperature. These results appear to indicate that p130 is the transforming protein of Fujinami sarcoma virus, and that its protein kinase activity plays a crucial role in cell transformation by this virus.

Alpharetrovirus↗
PubMed1980

Turtle-associated salmonellosis in the United States. Effect of Public Health Action, 1970 to 1976.

We examined the effect of state and federal legislative actions on the incidence of human salmonellosis associated with pet turtles. Using the Salmonella Surveillance System of the Center for Disease Control, we identified Salmonella serotypes that were and were not specifically turtle associated. From 1970 to 1976, there was a 77% reduction in frequency of turtle-associated serotypes and no consistent trend among non-turtle-associated serotypes. Decrease in frequency of turtle-associated serotypes correlated best with decrease in total production of pet turtles. Reduction in turtle-associated sertotypes temporally correlated with an 18% reduction in frequency of salmonellosis in children, aged 1 to 9 years. Frequency of turtle-associated serotypes rapidly fell in states importing turtles, in contrast to states producing them. Continued although infrequent occurrence of salmonellosis in children with pet turtles counsels against relaxing legislation concerned with its control.

Animals↗
PubMed1980

Cholera--a possible endemic focus in the United States.

In September and October 1978, after a case of cholera had been discovered in southwestern Louisiana, 10 more Vibrio cholerae O-Group 1 infections were detected in four additional clusters. All 11 infected persons had recently eaten cooked crabs from five widely separated sites in the coastal marsh, and a matched-triplet case-control study showed a significant relation between cholera and eating such crabs (P = 0.007). V. cholerae O1 was isolated from estuarine water, from fresh shrimp, from a leftover cooked crab from a patient's refrigerator, and from sewage in six towns, including three without identified cases. All isolates in Louisiana and an isolate from a single unexplained case in Texas in 1973 were biotype El Tor and serotype inaba; they were hemolytic and of a phage type unique to the United States--suggesting that the organism persisted undetected along the Gulf Coast for at least five years.

Adolescent↗
PubMed1980

Characterization of protein kinase activity associated with the transforming gene product of Fujinami sarcoma virus.

Fujinami sarcoma virus (FSV), a newly characterized avian sarcoma virus, produces a protein of 140,000 daltons (p140) in infected cells. p140 is the product of a fused gene consisting of a part of the gag gene of avian retrovirus and FSV-unique sequences which are not related to the src sequences of Rous sarcoma virus. In vivo, p140 was found to be phosphorylated at both serine and tyrosine residues. Immunoprecipitates of p140 with antiserum against gag gene-coded proteins had a cyclic nucleotide-independent protein kinase activity which phosphorylated p140 itself, rabbit IgG of the immune complex and alpha-casein, an externally added soluble protein substrate. The phosphorylation was specific to tyrosine of the substrate proteins. p140 was phosphorylated in vitro at the same two tyrosine residues that were phosphorylated in vivo. The phosphate transferred to tyrosine residues of p140 forms a stable bond: it does not turn over during the kinase reaction, and the 32P-phosphate of p140 labeled in vitro or in vivo is not transferred to alpha-casein. FSV-p140 differs from p60src, the transforming protein of Rous sarcoma virus, in its marked preference of Mn2+ to Mg2+ ions, and in its inability to use GTP instead of ATP as the donor of gamma-phosphate.

Alpharetrovirus↗
PubMed1980

Salmonella typhi: the laboratory as a reservoir of infection.

As a part of educational and proficiency exercises thousands of students and laboratory personnel have been exposed to Salmonella typhi. In a retrospective study 24 cases of laboratory-acquired typhoid fever in the United states during a 33-month period were identified; laboratory-acquired cases represented only 2.4% of all typhoid cases but 11.2% of the sporadic cases. Twenty-one of the 24 cases occurred when S. typhi was voluntarily introduced into the laboratory for educational proficiency testing or research purposes. Twelve patients were exposed to S. typhi when working with it as an unknown organism; another five were merely present in the laboratory. Obvious breaks in technique were found to be the cause of infection for only seven of the 24 patients, although infection of the others implies that breaks in technique occurred. Laboratory-acquired typhoid fever may severe as a marker for other less severe laboratory-acquired infections; these data suggest that such infections could be common.

Adult↗
PubMed1980

Norwalk virus gastroenteritis aboard a cruise ship: an outbreak on five consecutive cruises.

An explosive outbreak of gastroenteritis caused by a parvovirus-like (PVL) agent (Norwalk agent) affected 521 (64%) cruise ship passengers in 1977. The illness was characterized as mild-to-moderate and lasted one to two days. Principal symptoms experienced by ill passengers were nausea, vomiting, and diarrhea; fever was reported for approximately 25% of the patients. The outbreak was compatible with a common-source exposure, but no such exposure was identified. On the next four cruises, passengers experienced a similar gastrointestinal illness, but the outbreaks were less explosive, affected fewer persons, and symptoms appeared milder, on each subsequent cruise. No common source was identified, and person-to-person transmission may have occurred. The etiology of these outbreaks would have remained unknown were it not for the recent development of a specific radioimmunoassay (RIA) for the serologic identification of Norwalk virus and the measurement of antibody titers to the virus. A fourfold or greater rise in serum antibody titers to Norwalk antigen in serum from seven of eight ill passengers and the identification of Norwalk antigen in stool specimens from two ill passengers on the first cruise demonstrated that Norwalk virus caused this outbreak. The symptoms experienced by passengers on the four subsequent cruises suggest that a Norwalk agent probably also caused these outbreaks. In addition, a stool specimen from an ill passenger on cruise 3 contained Norwalk antigen.

Disease Outbreaks↗
PubMed1980

Diarrhea in a non-hospitalized rural Salvadoran population: the role of enterotoxigenic Escherichia coli and rotavirus.

To determine the role of rotavirus, enterotoxigenic Escherichia coli and enteropathogenic E. coli in diarrheal disease of non-hospitalized children and adults living in rural El Salvador, stool specimens were collected from 156 persons with diarrhea and 134 age- and sex-matched controls over a 1-year period. Enterotoxigenic Escherichia coli (ETEC) were isolated as frequently from controls (13.4%) as from diarrhea cases (12.2%). Enteropathogenic E. coli were isolated from 13 cases (8.3%) and 10 (7.7%) controls. Rotavirus was demonstrated in only five of the 129 specimens from cases examined; the five persons infected were less than or equal to 3 years of age. No invasive E. coli were found. Serotyping of ETEC revealed serogroups of ETEC previously associated with enterotoxigenicity but was not helpful in separating infection from disease. The etiology of diarrhea in this rural, non-hospitalized population was complex. Isolation of a known pathogen did not prove etiology. The rotaviruses, which have been isolated frequently from hospitalized persons, were rare. Further laboratory and epidemiologic studies in such populations are needed to identify those factors that determine pathogenicity.

Adolescent↗
PubMed1979

Bottle feeding as a risk factor for cholera in infants.

To determine risk factors for cholera in infants, a retrospective matched-pair study of 42 cases and their controls was undertaken during an outbreak of El Tor cholera in Bahrain in the autumn of 1978. The highest attack-rate of cholera (125/10 000) occurred in infants in the 6--11 month age-group, which corresponds to the weaning age in this community. Significantly more cases than controls were principally bottle fed (greater than 50% milk intake by bottle) than principally breast fed during the week before onset of illness (p=0.004). Analysis of various patterns of breast and bottle feeding did not determine whether the protection afforded by breast feeding was a negative effect (due to the lack of exposure to contaminated bottle feedings for breast fed infants) or a positive effect (due to protective functions of constituents of human breast milk). Cholera infection (with or without symptoms) among mothers of either case or control infants was uncommon (case mothers 3, control mothers 5), and mean serum vibriocidal and antitoxic antibody levels were similar for the two groups of mothers. These observations suggest that maternal infection did not affect the relative risk of infants having symptomatic cholera.

Antibodies, Bacterial↗