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Biomedical subjects

R S Baltimore

Publications and source records attributed to R S Baltimore.

52 records · Page 3Linked to original sources
PubMed1981

Antibody to group B Streptococcus type III in human sera measured by a mouse protection test.

Antibody to group B Streptococcus type III (GBS-III) was measured in human plasma and sera by using a test which measures the ability to protect outbred albino mice from an intraperitoneal challenge of GBS-III calculated to be lethal to 90% of the mice (LD90 dose). Of three samples from three different lots of commercial human immune serum globulin, none were protective despite the presence of antibody to the native type III polysaccharide. Nine specimens were tested from recipients of multivalent pneumococcal vaccine, and none were protective. Five specimens were tested from recipients of GBS-III polysaccharide vaccines who had responded with greater than 50 micrograms of specific antibody per ml in the blood. All of these were protective and could be diluted to titers of 1:10 to 1:40. Of two prevaccination sera with low levels of specific antibody, neither was protective. An unexpected finding which may limit the sensitivity of the mouse protection assay was that the human immune serum globulin and human serum with a very low level of antibody appeared to increase the lethality of the GBS-III test strain, resulting in LD50 values reduced to 0.01 of the usual LD50.

Animals↗
PubMed1980

Immunologic investigations of mucoid strains of Pseudomonas aeruginosa: comparison of susceptibility to opsonic antibody in mucoid and nonmucoid strains.

Mucoid strains of Pseudomonas aeruginosa, isolated from patients with cystic fibrosis, were studied for the prevalence of each of the seven Fisher immunotype antigens and were compared with their nonmucoid transformants, obtained by repeated subculturing, for susceptibility to opsonic antibody. Of the 30 strains tested--one from each of 30 patients--16 were typable and were tested in the opsonophagocytic assay with use of immunotype-specific rabbit antiserum; eight had significant opsonization by complement without antiserum. Of the eight strains requiring antiserum, seven strains required a higher minimum concentration of antiserum for a 1.0 log10 reduction of viable P. aeruginosa than the paired nonmucoid derivative. These end-point titers were significantly greater for nonmucoid Pseudomonas (P = 0.0007). A mucoid strain not requiring antibody for opsonization was shown to use primarily the alternative complement pathway. These results are consistent with the hypothesis that the immunodeterminant for opsonic antibody in nonmucoid strains is blocked in the mucoid strain.

Animals↗
PubMed1979

Immunodeterminant specificity of human immunity to type III group B streptococcus.

The type III polysaccharides of group B Streptococcus in its native state chemically consists of glucose, galactose, glucosamine, and sialic acid. The core of this polysaccharide lacks sialic acid and precipitates with type III antiserum to give a partial identity with the precipitate between the native antigen and this serum. The core determinant is immunochemically similar to the capsular polysaccharide of type XIV Streptococcus pneumoniae, while the native type III group B streptococcal polysaccharide does not cross-react with type XIV pneumococcal antiserum. In human sera, it is antibody directed to the native antigen which correlates very highly with opsonic immunity (r = 0.94) while a poorer correlation exists between antibody to the core antigen and opsonins (r = 0.51 P less than 0.001). In natural infections, as association exists between low levels of maternal antibody to the native antigen and risk of disease in the infant. This association is not true for antibody to the core structure, where both infected infants and their mothers have much higher levels of antibody to the core than the native antigens. Infected infants are also more likely to respond to infection by developing antibody to the native antigen. Immunization of 12 adults with multivalent pneumococcal polysaccharide induced significantly better antibody response to the core antigen than to the native, and this vaccine induced opsonic activity in only one recipient. Immunization of adults with type III group B streptococcal antigens induced antibody to the native determinant which correlated with opsonic activity. Therefore, it would appear that native group B streptococcal polysaccharides will provide the best candidate antigens for immunization.

Antibodies, Bacterial↗
PubMed1979

Mouse protection test for group B Streptococcus type III.

The mouse model has been used previously for the study of protection against challenge with strains of group B Streptococcus types Ia, Ib, and Ic, but investigators have not yet been successful in causing lethal disease when type III strains are inoculated. In this study, six clinical isolates belonging to serotype III were lethal in seven-week-old outbred albino mice; the 50% lethal dose (LD50) for mice tested ranged from 1.8 x 10(4) to 4.6 x 10(6). In contrast, a laboratory prototype strain of serotype III was not lethal. The lethality observed with this protection test depended on both the volume of the inoculum given and the medium in which the streptococci were suspended. LD50 values decreased as the volume of the inoculum, given intraperitoneally, increased, up to a volume of 1.5 ml. Hyperimmune rabbit antiserum to a clinical isolate of type III protected mice against an estimated 90% lethal dose of the isolate. Normal rabbit serum and heterologous antisera, except for one of two antisera to type Ia organisms, were not protective. Absorption of type III antiserum with whole organisms of serotype III or with purified, type III-specific polysaccharide inhibited protection of mice against type III organisms.

Absorption↗
PubMed1977

Meningococcal bacteremia: clinical and serologic studies of infants with mild illness.

We report three mildly ill infants who had meningococcal bacteremia and in whom meningitis or fulminant septicemia never developed. The infants were observed during a three-month period. Two of these infants had pneumonia, as evidenced by infiltrates on chest roentgenogram. The serogroups of the organisms isolated were B, Y, and 135. In none of the infants could specific bactericidal antibody be demonstrated in acute or convalescent serum.

Animals↗
PubMed1977

Antigenic specificity of opsonophagocytic antibodies in rabbit anti-sera to group B streptococci.

An opsonophagocytic assay has been developed which requires human polymorphonuclear leukocytes, immune serum, and complement for optimal killing of Group B streptococci. Only with all three of these components was killing of greater than 1.0 log10 of the initial inoculum achieved, using rabbit antisera directed to homologous strains of each of the five known serotypes of Group B streptococci. Titers of specific antisera which opsonized the strains and resulted in greater than 1 log 10 reduction of colony-forming units, ranged from 1:100 (serotype Ib) to 1:3200 (serotype Ia). Cross-reactions between serotype-specific sera and heterologous strains were seen in certain instances. Type Ic strain and serotype Ic antiserum demonstrated cross-reactions with types Ia and Ib which were explainable by known shared antigens among these types. The only other cross-reaction which resulted in greater than 1 log 10 reduction in colony-forming units was when unabsorbed antiserum to strain Ia was used to opsonize a strain of serotype III. Opsonization of 10 serotype III strains was demonstrated with a single type III antiserum. Killing of nine of these strains required polymorphonuclear leukocytes, complement, and antiserum, but one strain, D136C, the reference strain, could be killed (greater than 1 log 10 reduction in colony-forming units) without either complement or specific antiserum. Inhibition studies were performed utilizing large m.w. polysaccharide antigens extracted from each serotype. These antigens inhibited opsonization of homologous strains by homologous antisera with 50% inhibition points ranging between 0.5 and 4 mug.

Animals↗
PubMed1976

Perichondritis of the ear as a complication of acupuncture.

A 54-year-old woman developed pain, tenderness, and swelling at the site where a short acupuncture needle had been placed in the helix of the pinna. Staphylococcus aureus was isolated from this LESION. Which was treated with removal of the needle and intravenously administered nafcillin. The patient recovered completely and had no scarring.

Acupuncture Therapy↗
PubMed1976

Synergy of mecillinam (FL1060) with penicillins and cephalosporins against Proteus and Klebsiella, with observations on combinations with other antibiotics and against other bacterial species.

Thirty-five strains each of Klebsiella and Proteus were tested for susceptibility to mecillinam alone and in combination with ampicillin, carbenicillin, cephalothin, and cefazolin. Antibiotics were considered to be synergistic when there was a >/=fourfold reduction in minimum inhibiting concentration of both antibiotics in the combination as compared with that of each antibiotic alone. Synergy of mecillinam with ampicillin, carbenicillin, cephalothin, and cefazolin was demonstrated against 2, 3, 7, and 8 of the 35 strains of Klebsiella and against 14, 14, 19, and 24 of the 35 strains of Proteus, respectively. Synergy against the isolates of Proteus was related to species, whereas against Klebsiella it was related to susceptibility of the isolates to mecillinam. Tests of combinations of mecillinam with other antibiotics on the same and different species indicated that synergy was related to the antibiotic, the species, and the strains of organisms tested.

Anti-Bacterial Agents↗
PubMed1975

Coxsackievirus B5 infection and aseptic meningitis in neonates and children.

In metropolitan Washington, DC, an outbreak of aseptic meningitis in children was recognized in the summer and fall of 1972. Age-specific attack rates were highest in children less than 1 year of age. The incidence of cases showed two peaks: one in July and another in October. Coxsackievirus B5 was associated with cases occurring in July, August, and September, but was not implicated in the October cases. Seventy-six percent of the confirmed coxsackievirus B5 infections in aseptic meningitis patients occurred in infants less than 2 months old. Specific meningeal symptoms were less frequently observed in these young infants, although viral isolations were more common (13 of 15) compared to patients over 2 months of age (four of 19). Analysis of reported coxsackievirus B5 infections in Washington, DC, and the United States as a whole suggests a five- or six-year periodicity.

Adolescent↗
PubMedDate not supplied

Treatment of impetigo: a review.

A number of well-designed comparison studies have shown the superiority of oral or injectable antibiotics over typical treatment in the treatment of impetigo contagiosa. Erythromycin, phenoxymethyl penicillin, intramuscular benzathine penicillin G as well as clindamycin, cefaclor and amoxicillin with clavulanic acid have been shown to be extremely effective. Because of significant differences in study design, it is difficult to compare drugs investigated in different studies. Intramuscular benzathine penicillin G consistently has been associated with the highest cure rates, especially in studies specifically of streptococcal impetigo. It is unclear whether these high cure rates reflect superior efficacy or are the result of lesser compliance with oral medication, but the latter explanation is quite likely. This information generally translates into daily practice as a recommendation of a penicillin or an erythromycin preparation for streptococcal impetigo unless the lesions are small and few in number, in which case topical therapy is probably sufficient. If oral antibiotics are prescribed they should be given for 10 days. Systemic as opposed to topical antibiotics should be considered more strongly in situations where the incidence of impetigo is high, since these drugs are clearly superior in sterilizing the lesions quickly to prevent transmission. Other situations that favor the use of systemic as opposed to topical antibiotics include the presence of nephritogenic strains in the population, whether endemic or epidemic, more severe or spreading lesions and a population with poor hygiene.

Administration, Oral↗
PubMedDate not supplied

Late, late-onset infections in the nursery.

Infections affecting infants in the hospital nursery are generally divided into those with a prenatal onset and early- and late-onset postnatal infections. Little attempt has been made to differentiate infections affecting infants more than a week of age from those with an onset at several months of age. Three cases are presented which demonstrate how, currently, infants far older than one month of age are being treated for nosocomial, nursery-associated infections. This information has implications both for treatment decisions and for the gathering of epidemiologic data on nosocomial infections.

Bacterial Infections↗
PubMedDate not supplied

Nosocomial infections in the pediatric intensive care unit.

Nosocomial (hospital-acquired) infections are a major complication of serious illnesses. Severely ill patients have a greater risk of acquiring nosocomial infections, so this problem is greatest in intensive care units. Studies have demonstrated that nosocomial infections are largely preventable. Adherence to recommended techniques for patient care will have the greatest benefit in the intensive care unit. In this paper the background epidemiology of nosocomial infections is reviewed and related to pediatrics and intensive care units. Types of diseases, assistance equipment, and monitoring devices which are associated with a high risk of nosocomial infections are emphasized and specific steps for lowering this risk are listed.

Catheterization↗
PubMedDate not supplied

Pathogenesis of neonatal group B streptococcal infections.

Infections of the neonate due to the group B Streptococcus have been recognized since the 1930s, but it was during the 1970s that their incidence grew alarmingly throughout the world. A research effort stimulated by this problem has yielded significant new information about many facets of the pathogenesis of these infections. Immunologic investigations have pinpointed a lack of transplacentally acquired antibody as a significant risk factor. In the laboratory, assays of antibody which have a functional endpoint have demonstrated that the type-specific carbohydrate antigens play a major role in stimulating the development of protective antibody. These assays have been shown to correlate with certain tests of primary antigen-antibody interaction which do not have a functional endpoint, but are simpler to use in larger scale epidemiologic studies. These tools may be useful in filling the gaps in our current knowledge of the pathogenesis of this infection.

Antibodies, Bacterial↗