Search PubMed⌕ Search

Biomedical subjects

D S Hodes

Publications and source records attributed to D S Hodes.

At least 37 records · Page 2Linked to original sources
PubMed1984

Quantitative blood cultures in the evaluation of septicemia in children with Broviac catheters.

We applied quantitative methods of analysis to all blood cultures drawn during the course of treatment in 28 children with Broviac catheters in a central vein. Thirty febrile episodes in 14 of these patients were evaluated. Samples of blood obtained from a peripheral vein and through the central catheter were cultured quantitatively on agar plates and nonquantitatively in standard broth media. Catheters were judged to be a source of septicemia nine times in seven children. In all nine positive catheter samples, the concentration of pathogens was 10 times as great as that observed in the peripheral venous sample. The blood drawn through the Broviac catheter contained greater than or equal to 2000 colony-forming units per milliliter in six cases. Quantitative cultures in two patients with septicemia not attributable to the catheter yielded low colony counts in the catheter sample. Cultures of blood samples drawn through the catheter when a child was well were not helpful in predicting subsequent septicemia. The technique of inoculating blood directly onto agar plates is easily performed and superior to standard broth cultures, because it detected pathogens within 16 hours and identified infections with multiple organisms.

Adolescent↗
PubMed1984

Demonstration of differences between strains of Staphylococcus aureus by peptidoglycan fingerprinting.

Lysis of peptidoglycans of Staphylococcus aureus yields products that exhibit strain-specific patterns on analysis by thin-layer chromatography and polyacrylamide gel electrophoresis. The patterns are demonstrated when products of the endogenous autolysins are examined and are enhanced and/or altered by the use of exogenous murolytic enzymes. These fingerprinting techniques were applied to the study of 55 strains of S. aureus. Twenty-six strains were from patients in five localized hospital outbreaks, and 29 were obtained randomly from individual patients. With only two exceptions all strains from a given outbreak had an identical murolytic pattern, whereas the random strains showed variable patterns. Peptidoglycan fingerprinting may be an adjunct tool for the hospital epidemiologist and may also be valuable for the study of certain biologic aspects of interstrain differences.

Chromatography, Thin Layer↗
PubMed1982

Selection of temperature-sensitive mutants in persistent infection by parainfluenza virus type 3.

Vero cells persistently infected with parainfluenza virus type 3 (para 3) were examined for the production of temperature-sensitive (ts) mutants. After 6 months and 33 passages, ts mutants formed the great majority of the virus being shed into the supernatant fluid. Complementation studies gave evidence that the mutants shared a common lesion. Although ts mutants may play a role in the maintenance of persistent infection in this system, the mutants proved to be unstable when removed from the milieu of persistent infection. It is thus possible that their selection may be secondary to (an) unidentified factor(s) which play(s) a more primary role in the maintenance process.

Animals↗
PubMed1980

Tolerance in Staphylococcus aureaus: evidence for bacteriophage role.

The conversion of nontolerant Staphylococcus aureus to a tolerant organism is reported. It had been shown previously that a nontolerant strain produces tolerant progeny when it is incubated in media that contain a bacteria-free filtrate derived from cultures of each of the three tolerant stains of S. aureus. The tolerant progeny retain the characteristic tolerance upon serial subculture, and cell-free filtrates prepared from such subcultures are capable of converting nontolerant organisms to tolerant bacteria. A study of filtrates made from one of the tolerant strains revealed that all of the converting activity was sedimented by ultracentrifugation. DNase I and RNase A did not reduce the activity of the sediment, but Proteinase K completely diminished it. Equilibrium centrifugation of filtrates in cesium chloride showed that the conversion activity was maximal in the fraction with a density of approximately 1.445 +/- 0.015 g/ml. When a portion of this fraction was examined with the electron microscope, hexagonal bacteriophages (20 nm in diameter) were seen at this density. This observation seems to be evidence that a bacteriophage is involved in conversion of S. aureus from a nontolerant to a tolerant organism.

Immune Tolerance↗
PubMed1979

Establishment of persistent infection by parainfluenza virus type 3: role of a syncytium inhibitor.

A strain of parainfluenza virus type 3 (para 3) that had undergone a series of undiluted passages failed to produce syncytia when inoculated on to Vero cells at a high m.o.i. The strain repeatedly produced stable persistent infections. Persistently infected cells were resistant to superinfection by homologous virus, showed the presence of virus-specific antigen and shed low quantities of infectious virus into the supernatant fluid. The undiluted passage parainfluenza virus type 3 strain produced a substance that inhibited syncytium formation by homologous virus and by measles virus but appeared to have no effect on virus replication. This inhibitor had no demonstrable effect on unrelated viruses, including some that produced syncytia. It had a mol. wt. between 3500 and 14000, was acid- and heat-labile, and was inactivated by anti-para 3 serum.

Animals↗