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Biomedical subjects

N J Roberts

Publications and source records attributed to N J Roberts.

At least 91 records · Page 5Linked to original sources
PubMed1978

Cryptococcal meningitis. Cure despite cryptococcemia.

Cure of cryptococcal meningitis accompanied by cryptococcemia was achieved with amphotericin B therapy. Cryptococcal meningitis is associated with substantial morbidity and mortality, especially when accompanied by evidence of extraneural infection. Experience with the patient reported suggests that associated cryptococcemia is not invariably associated with treatment failure.

Adult↗
PubMed1978

Gentamicin use and Pseudomonas and Serratia resistance: effect of a surgical prophylaxis regimen.

An outbreak of prosthetic valve endocarditis due to methicillin-resistant Staphylococcus epidermidis prompted a change in antimicrobial prophylaxis for open heart surgery in a general hospital from a regimen of aqueous penicillin G, methicillin, and kanamycin to a 5-day regimen of cefazolin and gentamicin. As a result, total gentamicin use in the hospital more than doubled. Increased resistance of pseudomonas and serratia isolates paralleled the increased total use of gentamicin. For pseudomonas species, the incidence of gentamicin resistance increased from 3 to 15%; for serratia species, from 8 to 88%; and for the total of both organisms, from 4 to 28%. Resistance decreased rapidly after removal of gentamicin from the prophylaxis regimen. Review of serratia isolates from the urinary tract showed that gentamicin resistance was associated with prior antibiotic therapy, especially with gentamicin, care on the surgical services, especially the surgical intensive care unit, and presence of indwelling bladder catheters. Gentamicin use in a 5-day antimicrobial prophylaxis regimen for open heart surgery can represent a large proportion of the total hospital use of that antibiotic, with potential adverse effects on hospital flora.

Drug Resistance, Microbial↗
PubMed1977

Hyperthermia and human leukocyte functions: effects on response of lymphocytes to mitogen and antigen and bactericidal capacity of monocytes and neutrophils.

It has recently been demonstrated that fever, or hyperthermia, results in enhanced survival of lizards infected by Aeromonas hydrophila. In the present study, the effects of hyperthermia on certain immune functions were assayed in vitro with purified human leukocytes. Lymphocyte transformation responses to the mitogen phytohemagglutinin and the common antigen streptokinase-streptodornase were enhanced at 38.5 degrees C relative to 37 degrees C whether analyzed according to absolute counts per minute of incorporated tritiated thymidine or according to stimulation indexes. Enhancement of response was not accompanied by acceleration of response. Augmentation of transformation response was generally not seen at 40 degrees C; incubation at that temperature was associated with decreased cellular viability. Significant, though small, increases of the bactericidal capacity of polymorphonuclear leukocytes at 40 degrees C relative to 37 degrees C were shown at 1 h with Escherichia coli, Salmonella typhimurium, and Listeria monocytogenes, but not with Staphylococcus aureus. Mononuclear phagocytes did not show enhanced bactericidal capacity at the elevated temperature with any of these organisms in this in vitro system. Hyperthermia may enhance certain host defense mechanisms and warrants further study.

Adult↗
PubMedDate not supplied

Different antiviral spectra of human macrophage interferon activities.

The antiviral activity of alpha-interferon (IFN-alpha) produced by human leukocytes in response to viral infection has been considered to be independent of the virus which induced its production. Recently, however, IFN-alpha has been found to include at least eight different subtypes, as indicated by measurement of antigenic variability, DNA hybridization and amino acid sequencing. We considered the possibility that interferon heterogeneity may play a part in enhancing host antiviral defence and now present data suggesting that purified human macrophages, when exposed to different viruses, produce interferons having differing spectra of antiviral activity. These findings may provide a functional correlation for IFN-alpha heterogeneity.

Humans↗
PubMedDate not supplied

The concept of immunofocusing illustrated by influenza virus infection.

Influenza virus infection is an often-cited example of viral infection associated with immunosuppression. However, immune responses to the virus are complex and more accurately reflect an immunofocusing of host defensive capabilities: non-virus-specific responses are depressed or actively suppressed, while virus-specific systemic, local, and recruited responses develop. The result is commonly a resolution of infection without significant residual disease and with emergence of homotypic immunity. The overall combination of depressed alternate responses and enhanced antiviral immune responses might be assumed to have net defensive value for the host challenged by influenza virus.

Humans↗