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Biomedical subjects

R L Penn

Publications and source records attributed to R L Penn.

33 records · Page 2Linked to original sources
PubMed1984

Effects of overnight refrigeration on the microscopic evaluation of sputum.

Microscopic evaluation of sputum permits selection of specimens suitable for culture, assessment of likely pathogens, and the best interpretation of culture results. We prospectively evaluated 50 sputum specimens which were promptly submitted to our clinical laboratory; smears and cultures were performed both immediately and after 20 h of refrigeration. Specimens were grouped according to the numbers of squamous epithelial cells and neutrophils per low-power field present on coded Gram-stained smears. The numbers of bacteria in five oil immersion fields were used to characterize smears for predominant, mixed, or scanty forms. After refrigeration, only three specimens changed group from a definite loss of squamous epithelial cells, and only two changed group from a definite loss of neutrophils. Based on cellular composition, the majority of samples would have been processed identically both before and after refrigeration. In contrast, organism forms detected on smears and their relative quantities were dramatically altered after refrigeration. A predominant smear form was gained in 11 and lost in 8 refrigerated specimens. The frequent changes on smears observed overall resulted from both increases and decreases in numbers of bacteria and yeasts. The majority of sputum culture results were insignificantly affected by the refrigeration of specimens. We conclude that 20 h of refrigeration renders sputum useless for the microscopic evaluation of potential pathogens and the subsequent interpretation of culture results. However, overnight refrigeration does not affect the determination from smears of sputum suitability for culture based on cellular composition.

Bacteria↗
PubMed1984

Tissue morphology of Histoplasma capsulatum in acute histoplasmosis.

Reports of histopathology in acute histoplasmosis are rare. A case of fulminating acute histoplasmosis with hematogenous dissemination is described in which Histoplasma capsulatum was identified in transbronchial biopsy. This report represents the first morphologic description of H. capsulatum within human pulmonary tissue in the early phase of acute histoplasmosis. The yeast forms observed were of typical size, but they were present within the alveoli and were budding. No tissue granulomata were noted. This unusual morphology is in sharp contrast to the classic description of the organism in tissues and presented diagnostic difficulties, which are discussed in this report. Hematogenous dissemination is considered to be an important part of the pathogenesis of the disease, but it is rarely documented during the symptomatic phase of acute histoplasmosis. Cultural documentation of hematogenous dissemination was obtained in this patient. These observations stress the importance of obtaining culture material from extrapulmonary sites early in the course of acute histoplasmosis when a specific diagnosis is necessary.

Acute Disease↗
PubMed1984

The spectrum and significance of pleural disease in blastomycosis.

To determine the incidence and significance of pleural disease in blastomycosis, we reviewed the chest roentgenograms and medical records of 26 consecutive patients with biopsy- or culture-proved Blastomyces dermatitidis infection. Twenty-three of the 26 (88 percent) had radiographic evidence of blastomycotic pleural disease. Pleural reaction that regressed on therapy was mild (less than 1.0 cm thickening on EPA chest film) in 12. More extensive pleural thickening (1.5 to 3.0 cm) was observed in five, while four had effusions, and two had pneumothoraces. The 15 patients with mild or no visible pleural thickening were considered to have minor pleural involvement, while the 11 patients with greater than 1.5 cm pleural reaction, effusions, or pneumothoraces were considered to have major pleural disease. The ages, incidence of serious underlying disorders, and extra-thoracic dissemination were similar in both groups. Chest pain was more frequent in those with major pleural involvement (8/11 vs 4/15, p = 0.02), and their white blood cell count (14,300 +/- 1,200 c/mm3) was significantly higher than that of those with minor pleural involvement (10,600 +/- 1400, p less than 0.05). All of the patients with minor pleural disease responded to amphotericin therapy, but four of 11 (36 percent) with major pleural disease had an unfavorable outcome (relapse = two, death = two) (p = 0.02). In these patients with blastomycosis, pleural involvement was extremely common. Major pleural disease was associated with an adverse prognosis and may be an indication for prolonged therapy.

Adult↗
PubMed1983

Invasive fungal infections. The use of serologic tests in diagnosis and management.

Serologic tests are useful in providing a presumptive diagnosis of invasive fungal infection, allowing early institution of specific therapy. The judicious use of these serologic tests for circulating antibodies or antigens also may aid in analyzing response to treatment and in assessing prognosis. This review summarizes the currently available serologic tests for common invasive mycoses and discusses their relative usefulness and reliability.

Aspergillosis↗
PubMed1983

Nosocomial invasive Saksenaea vasiformis infection.

Saksenaea vasiformis is a zygomycete fungus found in soils worldwide; however, it is rarely documented as a cause of human disease. We describe what, to our knowledge, is the first nosocomial infection caused by S. vasiformis and the first documentation that this organism exists in Louisiana. The infection developed at an arterial catheter site in an otherwise healthy young man treated with high-dose corticosteroids and antibiotics for serious head trauma and caused a "cheesy" yellow necrosis of skin, muscle, tendon, and fascia. Resolution of the process occurred following removal of the arterial catheter and without antifungal therapy. The organism was isolated from deep surgical specimens on routine media but did not produce its characteristic sporangia until grown on Czapek's solution agar. It is recommended that zygomycete isolates not identifiable by routine procedures be grown on media that permit Saksenaea to sporulate.

Adult↗
PubMed1982

Effects of erythromycin in combination with penicillin, ampicillin, or gentamicin on the growth of Listeria monocytogenes.

Since the optimal antimicrobial therapy for infections caused by Listeria monocytogenes, particularly in patients allergic to penicillin, is uncertain, we investigated the in vitro effects of erythromycin, alone and in combination with other antibiotics, on listeriae. Seven strains of listeriae were inhibited but not killed by erythromycin, penicillin G, or ampicillin when tested by a microtiter broth dilution method. Susceptibility to gentamicin decreased when tryptose phosphate broth was substituted for Mueller-Hinton broth, but was independent of their calcium and magnesium concentrations. Quantitative killing studies performed with erythromycin combined with either penicillin G or ampicillin yielded antagonism for all strains, in contrast to microtiter checkerboard determinations, which did not indicate antagonism in all instances. Antagonism occurred with strains in both the stationary and log phases of growth and was slightly reversed by a 120-min preincubation of the listeriae with penicillin before the addition of erythromycin. Erythromycin and gentamicin were antagonistic in quantitative killing studies. Based on these in vitro findings, we conclude that the addition of gentamicin to erythromycin offers no advantage in the treatment of listeriosis in the penicillin-allergic patient.

Ampicillin↗
PubMed1982

Antibody responses in adult volunteers to pneumococcal polysaccharide types 19F and 19A administered singly and in combination.

The immunogenicity of the two major group 19 pneumococcal polysaccharides, types 19F and 19A, was studied in human volunteers. Antibody responses after vaccination with either 50 micrograms of type 19F polysaccharide, 50 micrograms of type 19A polysaccharide, or 25 micrograms of both polysaccharides premixed in a single injection revealed that the combined vaccine was immunogenic for both types, but that the optimal immunogen for each was the homologous polysaccharide. We concluded that vaccination with type 19F polysaccharide antigen, included in the current pneumococcal vaccine, does not induce a satisfactory heteroimmunogenic response to type 19A.

Antibodies, Bacterial↗