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Biomedical subjects

P T Davidson

Publications and source records attributed to P T Davidson.

49 records · Page 3Linked to original sources
PubMed1976

Mycobacterium szulgai; a new pathogen causing infection of the lung.

A case of infection with a newly described scotochromogenic mycobacterial species, Mycobacterium szulgai, is presented, and all the reported cases are summarized. The disease is characterized by its predominance in middle-aged men, the occurrence of cavitary pulmonary lesions, and a good response to triple-drug therapy. Sputum samples are usually positive on smear. Drug susceptibility studies show a greater degree of susceptibility to several antituberculosis drugs than the usual scotochromogen. Mycobacterium szulgai has frequently been confused with other atypical mycobacteria, but serologic and other laboratory characteristics are distinct and should allow proper identification.

Adult↗
PubMedDate not supplied

Treatment of disease due to Mycobacterium intracellulare.

During eleven and one-half years, 122 patients with M. intracellulare disease were treated at National Jewish Hospital and Research Center, Denver, Colorado. Of the 81 patients treated with multiple drug chemotherapy, 63 (78%) were considered to be treatment successes. On follow-up (averaging 55 months) 40 of the 63 patients had remained clinically stable or improved and 12 had grown worse. Ten of these 63 patients had relapsed. Of the 63 patients considered to be treatment successes, 23 (36.5%) had died during follow-up, mostly of pulmonary disease. Of the 18 patients who failed to respond to chemotherapy, 2 were later successfully treated with surgery, 5 patients were clinically worsening, and 8 (44%) had died during a follow-up period averaging 43 months. A group of 41 patients had indeterminate results with chemotherapy. Eight had died while in the hospital. Follow-up information after an average of 43 months indicated that 9 patients became treatment successes (5 with chemotherapy, 4 with surgery), 12 were clinically stable or improving, and an additional 13 had died for a total of 21 deaths (51%). The overall success of treatment in the 122 patients was 61%. Fifty-two (43%) died during the study. Many patients will respond to drug therapy and remain clinically well for years. Because of the potential seriousness of this disease in some patients, multiple drug chemotherapy should be used.

Adult↗
PubMedDate not supplied

Disease due to Mycobacterium intracellulare: its possible association with human leukocyte antigens.

Most of the population of the United States is exposed to Mycobacterium intracellulare, but only a few persons develop disease due to this organism. This fact suggests that certain host factors may predispose an individual to this disease. To investigate the possibility that susceptibility to disease due to M. intracellulare may be determined by genetic factors, as evidenced in profiles of human leukocyte antigens (HLAs), we examined 41 consecutive patients with use of tissue typing for HLA-A and HLA-B loci. The association in individuals between disease and frequency of HLAs was analyzed and compared with control data of HLA frequencies in the caucasian American population. The observed frequencies of many HLAs were different from those expected, but none of the individual differences were significant statistically. However, the frequency of the haplotype A2-B12 was found to be significantly higher than the expected frequency (P less than 0.05). While the population of patients studied was small, the observed increase in the haplotype frequency may indicate a possible predisposing genetic factor in this disease.

Adult↗
PubMedDate not supplied

Experimental infections with Mycobacterium intracellulare.

Information on the pathogenesis of Mycobacterium intracellulare disease is necessary to facilitate the finding of effective drugs. As a first step, development of a suitable small-animal model is needed. Examination of several strains of mice and M. intracellulare led us to conclude that the Swiss Webster strain of mice and the 8330 and 571-8 strains of M. intracellular were most useful. Since the use of normal mice resulted only in a chronic type of disease lasting many months, immune suppression by means of trypan blue, silica, or a combination of cyclophosphamide and cortisol was attempted in order to generate an acute infection. Higher numbers of bacilli were recovered from organs in the immune-suppressed animals as compared with the controls, more so in the lungs than in the spleen, although no acute type of disease process resulted.

Animals↗
PubMedDate not supplied

Surgical treatment of atypical mycobacterial lymphadenitis in children.

A retrospective study was done on 38 patients with atypical mycobacterial lymphadenitis who underwent surgical intervention at The Children's Hospital, Denver, between the years 1953 and 1983. One group consisting of 18 patients had incision and drainage of the abscess or biopsy only. Sixteen of these patients developed a draining sinus or recurrent disease within a few months despite the use of antituberculous drugs or antibiotics. The other group, consisting of 20 patients, were treated initially by total excision of the inflammatory mass with no persistence or recurrence. The groups were found to be comparable with respect to age, sex, race, duration of disease and size and site of the lymph node involved. We recommend total excision of the lesion without antituberculous medications as the first choice of treatment.

Antitubercular Agents↗