Publications by authors named "Middlebrook G"

Background: Inpatient hypoglycemia is associated with increased morbidity and mortality. After a hypoglycemic event, the likelihood of additional episodes increases. The Joint Commission recommends evaluating all episodes of hypoglycemia for root-cause analysis.

View Article and Find Full Text PDF

Rapid methods for the differentiation of Mycobacterium tuberculosis/M. bovis (TB complex) from other mycobacteria (MOTT bacilli) were developed and evaluated in a three-phase study. In the first phase, techniques for identification of Mycobacterium species were developed by using radiometric technology and BACTEC Middlebrook 7H12 liquid medium.

View Article and Find Full Text PDF

Drug susceptibility studies on strains of Mycobacterium tuberculosis isolated from widely different populations of patients and tested by two different techniques indicated that all 55 strains resistant to rifampicin were also resistant to isoniazid, while many strains resistant to isoniazid were found to be susceptible to rifampicin. This observation, which has as yet unknown laboratory and clinical significance, may be particularly useful in management of patients. Further studies are called for to establish this relation.

View Article and Find Full Text PDF

A total of 106 isolates of Mycobacterium tuberculosis were tested for drug susceptibility by the conventional 7H11 plate method and by a new rapid radiometric method using special 7H12 liquid medium with 14C-labeled substrate. Results obtained by the two methods were compared for rapidity, sensitivity, and specificity of the new test method. There was 98% overall agreement between the results obtained by the two methods.

View Article and Find Full Text PDF

Three methods for rapidly determining the susceptibility of Mycobacterium Tuberculosis isolates to isoniazid, rifampin, ethambutol, streptomycin, and para-aminosalicylic acid were evaluated in a large-scale, blind study. Two of the methods measured evolution of CO2 from radio-labeled substrate (14CO2), and one method measured incorporation of 3H-uracil into ribonucleic acid. Rapid indirect drug-susceptibility test results for nearly 300 isolates were compared with those obtained using a standard modified proportion technique.

View Article and Find Full Text PDF

The formulation of media for selective, automatable, radiometric detection of growth of Mycobacterium tuberculosis in vitro is described. Palmitic-1 acid labeled with carbon-14 and formic-14C acid were compared as substrate sources of [14C]O2 in media deficient in carbohydrate and containing appropriate antimicrobial agents that are not active against tubercle bacilli. A preliminary clinical laboratory study of a medium containing 4 microCi palmitic-1-14C acid per ml showed that this method might provide the basis for practical laboratory use.

View Article and Find Full Text PDF

Peritoneal exudates elicited in BCG-infected guinea pigs with caseinate yield cell cultures that have been shown to produce soluble material capable of sterilizing certain bacteria if the cultures are incubated with the specific antigen purified protein derivative or the lectin phytohemagglutinin. This material is now shown to have the following properties: (i) strongly adsorbable to glass; (ii) strongly adsorbable to cation- and not to anion-exchange resins but not elutable with mineral acid or solutions of high ionic strength; (iii) strongly adsorbable to cellulose nitrate membrane filter materials and quantitatively elutable with dilute HCl, providing a convenient method for partial purification; (iv) relatively stable over a wide range of pH and temperature; (v) antagonized by polyanions and by iron ions; (vi) active against the three gram-positive bacilli tested and not against the other organisms tested: (vii) more active in alkaline than in acidic media; and (viii) inactivated by proteolytic enzymes.

View Article and Find Full Text PDF

In an in vitro model of cellular immunity, the antibacterial product of immunologically mediated mononuclear cell activation was studied from guinea pigs infected with listeriae and rickettsiae and compared with the product previously described from animals infected with mycobacteria. We found that this product, active against gram-positive bacilli, appeared to be identical in the three different infections with regard to its heat stability, its chromatographic adsorption and elution pattern, its susceptibility to inactivation by proteolytic enzymes, and its antibacterial spectrum

View Article and Find Full Text PDF

To test the effectiveness of irradiating the upper air of a room with ultraviolet light at reducing the concentration of airborne tubercle bacilli, the susceptibility to the germicidal effects of ultraviolet light, Z, was determined for various mycobacteria. Virulent tubercle bacilli and bacille Calmette-Guérin (BCG) were equally susceptible to ultraviolet radiation, whereas Mycobacterium phlei had 10 times their resistance (Z, approximately one-tenth that for M. tuberculosis).

View Article and Find Full Text PDF

A study was carried out to investigate the drug resistance patterns of the prevalent tubercle bacilli in pulmonary and extrapulmonary tuberculosis in and about the city of Lahore, Pakistan. This report includes 168 strains of Mycobacterium tuberculosis isolated from the same number of pulmonary tuberculosis cases (100 untreated cases, defined as patients either having no history of anti-tuberculous therapy or having had chemotherapy for not more than 10 days; 68 treated, defined as having had chemotherapy for more than 10 days), and 162 strains from the same number of extrapulmonary tuberculosis cases (77 untreated, 38 treated and 47 doubtful). The proportion method of drug susceptibility assay was employed.

View Article and Find Full Text PDF

Glycolipids were extracted from mycobacteria with methanol and chloroform and purified by silicic acid chromatography. These glycolipids were studied for their serologic activity by direct and indirect (Coomb's) passive hemagglutination, and by inhibition methods. Three families of serologically active glycolipids called A, B and C, plus cardiolipin, were isolated.

View Article and Find Full Text PDF

Serological tests with serologically active glycolipids from Mycobacterium bovis BCG were investigated for their possible use in the diagonis of mycobacterioses. The results were positive with 95 percent of sera from patients with far advanced and moderately advanced tuberculosis, 80 percent of sera from patients with newly diagnosed tuberculosis and 75 percent of patients with atypical mycobacterial diseases. "False" positive serologic reactions were obtained from 4 percent or less.

View Article and Find Full Text PDF

In experiments described herein, it was observed that guinea pigs with delayed-type hypersensitivity to tuberculoproteins under various experimental conditions, with or without passive transfer of serum from immune donors, manifested no acquired immunity against aerogenically induced tuberculosis. These results are discussed in relation to the previous observations of other investigators and to the general problem of cellular hypersensitivity and immunity against facultative intracellular bacteria.

View Article and Find Full Text PDF

Materials and methods are described for the construction of an inexpensive multiple-well dispensing apparatus for use in serological microtitration.

View Article and Find Full Text PDF