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Biomedical subjects

G D Campbell

Publications and source records attributed to G D Campbell.

At least 19 recordsLinked to original sources

Pleural effusion. What you can learn from the results of a 'tap'.

Pleural effusion may result from many disorders, some of them serious. Fortunately, this body fluid is easily accessible, and knowledge of its characteristics is an important tool in diagnosing the underlying disease. The authors describe radiographic and laboratory tests to use in determining the source of the problem.

Humans

Distribution of the Lyme disease vector, Ixodes dammini (Acari: Ixodidae) and isolation of Borrelia burgdorferi in Ontario, Canada.

Ixodes dammini Spielman, Clifford, Piesman & Corwin was confirmed at Long Point, Lake Erie, Ontario, on small mammals and white-tailed deer and by dragging for ticks. Mean intensities of up to 16.2 larvae and 2.1 nymphs were found on Peromyscus leucopus (Rafinesque), with an overall prevalence of infestation up to 92%. Adult I. dammini (101.6 +/- 77.63) (mean +/- SD) were found on 8 white-tailed deer, Odocoileus virginianus (Zimmerman). The seasonal pattern of recovery of ticks from hosts and the environment resembled that described elsewhere. I. dammini was not found on 952 small mammals trapped at 25 other localities throughout Ontario, although other ticks (Derma-centor variabilis (Packard), Ixodes angustus Neumann, I. marxi Banks, I. muris Bishopp & Smith) were encountered sporadically. I. dammini is not widespread or common in Ontario other than at Long Point. Borrelia burgdorferi was isolated from 10 of 151 P. leucopus; from larval and nymphal I. dammini; and from nymphal and adult D. variabilis, all from Long Point. B. burgdorferi was not recovered from 116 small mammals from localities other than Long Point. Seropositive P. leucopus (indirect fluorescent antibody test titer > or = 1:20) were common (up to 30% prevalence in July 1988, n = 23) on Long Point. Where I. dammini was not found, the prevalence of seroreactors among Peromyscus was 0 (15 sites), < 12% (5 sites), and 29% (1 site); seroprevalence at 1:20 could not be calculated for a further 4 sites examined in 1987. Antibody to B. burgdorferi was also detected in other small mammals at some sites. Such antibody was interpreted as possibly cross-reacting or caused by direct transmission.

Animals

Microbial etiology of acute pneumonia in hospitalized patients.

The purpose of this study was to determine the microbial etiology of pneumonia by using strict criteria among a group of hospitalized patients. Patients with acute community-acquired or hospital-acquired pneumonia were studied in a systematic and comprehensive manner for bacterial, viral, chlamydial, mycobacterial, and fungal pathogens. A total of 198 patients with 204 episodes of pneumonia were evaluated. Despite 100 percent follow-up of all surviving patients, a specific etiologic agent could be found in only 103 episodes. Among 154 episodes of community-acquired pneumonia, a diagnosis was made in 79; the most common pathogen was from the genus Legionella, followed by various Gram-negative enteric bacteria, Gram-positive cocci, influenza A virus, and Mycoplasma pneumoniae. The etiologic agent was found in 24 of the 50 patients with hospital-acquired pneumonia; no pathogen predominated. We conclude that even when elaborate diagnostic studies are done, including many invasive procedures, the etiology can be determined in only about half of the patients with acute pneumonia. The pathogens of pneumonia in this study are not markedly different between community-acquired and hospital-acquired infection.

Acute Disease

Diphosphoryl lipid A protects rats from lethal hyperoxia.

Bacterial endotoxin has been shown to protect rats from lethal hyperoxia. The structure of endotoxin contains diphosphoryl lipid A (DPL) as the lipid backbone stripped of protein and polysaccharides. DPL is the component of the endotoxin molecule that has been demonstrated (in previous studies) to be responsible for the immunologic, mitogenic, pyrogenic, and lethal properties of endotoxin. Monophosphoryl lipid A (MPL) is a nonpyrogenic, nontoxic modification of the DPL molecule that retains its immunostimulatory and mitogenic properties. We hypothesized that DPL may be the actual active component of endotoxin that protects rats from lethal hyperoxia. We also hypothesized that the protection from hyperoxia that is afforded by the DPL component may be related to endogenous release of tumor necrosis factor alpha which should allow MPL to also be protective. To test these hypotheses, we performed a series of experiments in which rats were treated with endotoxin, DPL, MPL or vehicle and exposed to room air or hyperoxia. We found that DPL and endotoxin both protected rats from lethal hyperoxia, but MPL alone was not protective. Even though MPL was not protective, DPL and MPL both increased endogenous release of tumor necrosis factor alpha early after injection (peak DPL level, 3619 +/- 1500 pg/ml, peak MPL level, 4038 +/- 500 pg/ml). Protection in both the endotoxin- and DPL-treated animals was associated with increases in lung antioxidant enzyme activities. We concluded that DPL protect rats from hyperoxia but that MPL is not protective in spite of its immunostimulatory and mitogenic effects.

Animals

Comparison of acridine orange stain with culture and gram stain of needle aspirate in experimental Pseudomonas pneumonia.

The sensitivity and specificity of culture, acridine orange stain, and Gram stain were determined using needle aspiration (NA) material obtained from 82 rats with acute Pseudomonas aeruginosa pneumonia and 18 control rats. Lungs were then processed for either bacterial quantitation or histopathologic examination. NA culture proved to be the most sensitive and specific (55 and 100%, respectively). Sensitivity of acridine orange stain was 40%, whereas Gram stain was only 29%. The specificity of each stain was at least 94%. Lung bacterial concentrations influenced the sensitivities of all three techniques, with better sensitivity found in NA samples obtained from lung with bacterial concentration of at least 10(4) colony-forming units (cfu) of P. aeruginosa. Acridine orange and Gram stain results were similar except in NA samples from lung with bacterial concentration of less than 10(4) cfu in which acridine orange stain was more sensitive. The presence of stains identifying bacteria collected from animals with sterile NA culture was found in a small but significant number of samples, suggesting the presence of nonviable though stainable organisms. Use of all three techniques (culture, acridine orange stain, and Gram stain) increased sensitivity to approximately 70% with minimal decrease of specificity.

Acridine Orange

What is pellagra?

Explore the source record for details and available documents.

Feeding Behavior

Histoplasmin-CYL, a yeast phase reagent in skin test studies with humans.

A yeast phase histoplasmin, designated CYL, was studied in 156 humans living in areas of the United States endemic for histoplasmosis, coccidioidomycosis, or both fungal entities. Comparisons were made with Food and Drug Administration reference mycelial histoplasmin. Among persons without concurrent spherulin sensitivity, reactor rates and sizes were the same with both reagents. Some persons with spherulin sensitivity reacted only to the mycelial reagent. Histoplasmin-CYL skin tests did not induce significant changes in complement-fixing antibody in histoplasmin-reactive subjects.

Antibodies, Fungal

Acute miliary blastomycosis presenting as fluminating respiratory failure.

A patient with miliary blastomycosis had acute fulminating respiratory failure requiring prolonged external ventilatory support. Treatment consisted of antifungal chemotherapy with two drugs and administration of corticosteroids. Restrictive ventilatory impairment and exercise-induced hypoxemia persist at one year after completion of therapy.

Acute Disease

XYY karyotype, female phenotype and gonadal dysgenesis. A case report.

A rare association of female phenotype with the 47,XYY karyotype in a 14-year-old White girl is described. She was studied because of her short stature and proved to have gonadal dysgenesis. She showed no masculinization and there were no Turner stigmata. Her intelligence was normal, she was sociable and her outlook was feminine.

Adolescent

Cutaneous sporotrichosis in forestry workers. Epidemic due to contaminated Sphagnum moss.

In December 1975 and January and February 1976, an epidemic of cutaneous sporotrichosis occurred in Mississippi among forestry workers and other persons exposed to sphagnum moss used in packing pine seedlings. Seventeen cases were identified, 15 of which were from patients who had been exposed to sphagnum moss from a single source. Attack rates were significantly higher among workers exposed to this moss than among those not exposed. Sporothrix schenckii was cultured from the implicated batch of sphagnum moss but not from other batches. The source of contamination of the sphagnum moss that caused this epidemic and sphagnum moss associated with similar epidemics is unknown. One worker without cutaneous sporotrichosis may have had asymptomatic pulmonary sporotrichosis.

Agricultural Workers' Diseases

Miconazole therapy for fungal meningitis.

Eight patients with fungal meningitis (5 with the coccidioidal type, 2 with cryptococcal, and 1 with histoplasmosis) were treated with intravenous (IV) and intrathecal (IT) miconazole after previous therapy with amphotericin B proved unsuccessful. Miconazole was well tolerated with both IV and IT administration. The CSF concentration of miconazole one hour after an IV infusion of 800 mg was 0.1 to 0.3 microgram/ml. When 20 mg of miconazole was administered intrathecally via lumbar injection in patients with coccidioidal meningitis, 6.5, 2.4, 0.77, and 0.24 microgram/ml, respectively, was found in the CSF at the cisternal level at 12, 24, 48, and 72 hours, respectively. Miconazole is apparently an effective fungistatic drug of low toxicity and is a potentially useful agent in the treatment of systemic mycoses and fungal meningitis, in particular.

Adult

Effects of ascorbic acid on glucose-6-phosphate dehydrogenase-deficient erythrocytes: studies in an animal model.

There is little information available concerning the possible effects of ascorbic acid on glucose-6-phosphate dehydrogenase (G-6-PD) -deficient erythrocytes. We therefore studied the survival of G-6-PD-deficient cells, incubated with ascorbic acid, in rats with partial reticuloendothelial and complement blockade. Animals were pretreated with ethyl palmitate and cobra venom factor. They were then transfused with 51Cr-labeled erythrocytes which had been incubated in the presence or absence of ascorbic acid. G-6-PD-deficient cells, incubated with ascorbic acid, had impaired survival when compared to that of controls. G-6-PD-deficient cells, in the absence of ascorbic acid, had survival times equal to those of normal control erythrocytes. At the concentrations used, ascorbic acid did not appear to alter the survival of normal cells. Ascorbic acid causes premature loss of G-6-PD-deficient human erythrocytes in this rat model. On the basis of previous clinical and experimental observations, as well as this study, caution should be used when administering ascorbic acid in large doses to individuals who might be G-6-PD deficient.

Animals

Cutaneous histoplasmosis.

Cutaneous lesions as a manifestation of histoplasmosis, primarily a disease of the respiratory system, are rare and most commonly appear secondary to progressive dissemination. A patient with documented progressive, disseminated histoplasmosis, having been treated previously with amphotericin B, presented on a second occasion with cutaneous lesions as the chief complaint. Biopsy and cultures of these lesions were positive for Histoplasma capsulatum. A review of the English literature revealed only 7 reported cases of secondary skin histoplasmosis in the past 20 years. All patients, including the current one, either had diseases associated with depressed immunity or were receiving steroid therapy.

Adult