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Biomedical subjects

T L Hadfield

Publications and source records attributed to T L Hadfield.

At least 55 records · Page 3Linked to original sources
PubMed1989

Detection of Cryptosporidium oocysts in human fecal specimens by an indirect immunofluorescence assay with monoclonal antibodies.

An indirect fluorescence assay (IFA) with monoclonal antibodies developed for the detection of Cryptosporidium oocysts in fecal smears (Meridian Diagnostics, Inc., Cincinnati, Ohio) was compared with the Zeihl-Neelsen-modified acid-fast stain (MAFS) in 119 human fecal specimens collected between 1984 and 1987. The sensitivity of the IFA was 100%; all 56 specimens positive by MAFS exhibited fluorescence. There were 63 specimens negative for Cryptosporidium sp. by MAFS; of these, 61 were negative by IFA (97% specificity). This discrepancy may reflect an increased sensitivity of the IFA to detect oocysts that were not visualized by MAFS because of faint staining or a paucity of organisms. On average, the IFA required less time than the MAFS (1 versus 5 min, respectively) when only rare or few oocysts were present. Cost comparison of reagents showed the IFA to be three times more expensive. The IFA offers a reasonable alternative to the MAFS because of its high sensitivity and specificity, the simplicity of performing it and interpreting results, and its capability of providing a definitive diagnosis of Cryptosporidium oocysts.

Animals↗
PubMed1988

Acid secretion and serum gastrin levels in individuals with Campylobacter pylori.

Campylobacter pylori may cause gastritis and has been proposed as an etiologic factor in the development of peptic ulcer. However, it may be an acid-sensitive microbe and before it can be implicated in the pathogenesis of peptic ulcer, it should be consistently found in ulcer patients with normal acid secretion. Thirty-six patients with C. pylori by Warthin-Starry stain underwent gastric analysis; 25 were normochlorhydric and 11 hypochlorhydric. Ulcers were present in 19 normochlorhydric patients (10, gastric; 9, duodenal) and 2 hypochlorhydric patients (gastric). Median basal acid output was higher for those with duodenal ulcer (38 mmol/h) than gastric ulcer (28 mmol/h) or miscellaneous endoscopic features (33 mmol/h). The hypergastrinemia seen in 12 patients with negative secretin provocation tests was believed to be due to various nongastrinoma conditions. Campylobacter pylori was found in 6 normogastrinemic patients with elevated acid output and in 1 gastrinoma patient with marked acid hypersecretion. Histologic chronic gastritis was present in all subjects and 29 had active chronic gastritis. Twenty-three patients were taking H2-receptor antagonists at the time of diagnosis which did not seem to interfere with culture results. Using standard acid secretory tests, we conclude that C. pylori can survive in a wide range of acid conditions.

Adult↗
PubMed1988

Comparative efficacy and toxicity of roxithromycin and erythromycin ethylsuccinate in the treatment of streptococcal pharyngitis in adults.

Roxithromycin is a novel oxime ether derivative of erythromycin. Previous studies have demonstrated similar in-vitro activity for roxithromycin and erythromycin. Roxithromycin has improved pharmacokinetic properties and may be a useful alternative agent for infections where erythromycin is indicated. We compared the efficacy and toxicity of roxithromycin and erythromycin ethylsuccinate in the treatment of streptococcal pharyngitis in adults. We also assessed compliance with treatment between the two agents. Roxithromycin and erythromycin ethylsuccinate were equally effective in resolving the symptoms and signs of pharyngitis. Erythromycin ethylsuccinate was superior to roxithromycin in achieving microbiological cure (90% vs. 33%, respectively). No differences were observed in toxicity or compliance with treatment between the two agents. Based on this prespective clinical trial, roxithromycin is not considered to be an acceptable alternative agent for acute streptococcal pharyngitis in adults.

Adolescent↗
PubMed1987

Susceptibility of Bordetella pertussis to five quinolone antimicrobic drugs.

Five quinolone antimicrobic agents were tested to determine the mean inhibitory concentration (MIC) of each of 17 clinical strains of Bordetella pertussis by the agar dilution method. Ciprofloxacin demonstrated the best in vitro activity with an MIC90 of 0.06 microgram/ml. Norfloxacin, ofloxacin and enoxacin were also highly active with MIC90s of 0.25, 0.25, and 0.5, respectively. Cinoxacin was only moderately active (MIC90 4.0 microgram/ml).

Anti-Bacterial Agents↗
PubMed1986

Life-threatening cat-scratch disease in an immunocompromised host.

We describe a renal allograft recipient with cat-scratch disease in whom refractory hypotension, severe metabolic acidosis, pulmonary infiltrates, and encephalopathy developed. The patient first presented with a history of cat bites and scratches, fever, headache, and arthralgias. Four weeks later, the clinical presentation of septic shock suddenly developed in the patient. Cat-scratch disease was documented clinically and by finding delicate pleomorphic bacilli in Warthin-Starry silver stains of biopsy specimens taken from the primary inoculation site and regional lymph node. The administration of intravenous sulfamethoxazole and trimethoprim, erythromycin lactobionate, and tobramycin sulfate therapy correlated with recovery. Although cat-scratch disease is usually a benign, self-limited illness, this article illustrates its systemic nature, its potential for devastating complications in the immunocompromised host, and its possible response to vigorous antibiotic therapy.

Adult↗
PubMed1985

Depression of lymphocyte responses to mitogens in mangabeys with disseminated experimental leprosy.

Mononuclear cells from mangabey monkeys with disseminated experimental leprosy had increasingly severe depression of blastogenic responses to phytohemagglutinin, concanavalin A, and pokeweed mitogen as the disease progressed. Blastogenic responses were not depressed in cells from mangabeys with more localized disease. Blastogenic responses of cells from normal mangabeys appeared to vary with a circannual rhythm. The demonstration of significant negative correlations between the blastogenic responses to mitogens and the percentages of OKT8+ cells suggested that the mangabey OKT8+ subset may contain cells with suppressor function. The depressed responses to mitogens by cells from monkeys with disseminated experimental leprosy were associated with relatively high percentages of OKT8+ cells. Polyclonal immunoglobulin plaque-forming cell responses to pokeweed mitogen were depressed in cells from experimentally infected mangabeys. The results indicated that defects in immune regulation may occur in experimental leprosy in mangabeys, similar in some respects to the defects that have been reported in human leprosy.

Animals↗
PubMed1985

Cat scratch disease bacilli in the conjunctiva of patients with Parinaud's oculoglandular syndrome.

Unilateral conjunctivitis with regional lymphadenitis has been designated Parinaud's oculoglandular syndrome (POGS). The cause has been attributed to various infectious agents, especially leptothrix and the unidentified agent of cat scratch disease (CSD). In 1983-84 the cause of CSD in lymph node and skin was established as small pleomorphic gram-negative bacilli. We now report identical bacteria in the conjunctival lesions of 9 of 24 patients with POGS. This confirms the belief that the CSD bacillus is a major cause of POGS.

Adolescent↗
PubMed1985

An outbreak of antibiotic-resistant Salmonella enteritidis in Liberia, West Africa.

Between October 1980 and August 1982, 100 patients in the pediatric population at Curran Lutheran Hospital, Zorzor, Liberia were identified as having multiple drug-resistant Salmonella enteritidis serotype enteritidis. The illness usually presented as an enteric fever but also as meningitis, gastroenteritis, empyema, subcutaneous abscesses, chronic otitis media, or a combination of these conditions. Predisposing factors were young age and debilitation from malnutrition or measles. The mortality of infected patients was 27.8%. The organism was originally misidentified as a Citrobacter species because of a delayed reaction on lysine decarboxylase medium. Incubation of the medium for five days resulted in a positive reaction that identified the organism as a Salmonella species. The isolates were resistant to multiple antibiotics. Genes mediating resistance were located on a 120-megadalton conjugative plasmid. A cryptic nonconjugative 40-megadalton plasmid was also present in several isolates.

Adolescent↗
PubMed1985

Leprosy in a mangabey monkey--naturally acquired infection.

Naturally acquired leprosy was detected in an otherwise normal "sooty" mangabey monkey (Cercocebus atys). This animal was imported from West Africa in 1975 and developed clinical symptoms of leprosy in 1979. Histopathologic findings were those of subpolar-lepromatous to borderline-lepromatous leprosy in the Ridley-Jopling classification. The disease was progressive, with crippling neuropathic deformities of the hands and feet. The disease regressed under specific therapy. The etiologic agent was identified as Mycobacterium leprae by the following criteria: invasion of nerves of host, staining properties, electron microscopic findings, noncultivable on mycobacteriologic media, DOPA-oxidase positive, lepromin reactivity, infection patterns in mice and armadillos, sensitivity to sulfone, and DNA homology. We believe the animal acquired the disease from a patient with active leprosy. The mangabey monkey offers promise as a primate model for leprosy, and adds a third reported species to animals with naturally acquired leprosy.

Animals↗
PubMed1984

Cat-scratch disease. Bacteria in skin at the primary inoculation site.

Cat-scratch disease is a zoonotic infection characterized by a skin papule at the site of the scratch followed by regional lymphadenitis. Recently, small gram-negative pleomorphic bacilli were demonstrated in sections of lymph node from patients with the disease. We now report identical bacteria in the primary inoculation site of three patients with cat-scratch disease. Lymph nodes from two of these patients also contained the same bacilli. Identical bacteria in both skin and lymph nodes from these patients are further evidence that the bacilli are the cause of cat-scratch disease. In early infections, biopsy of the primary site of inoculation and demonstration of bacilli may replace excision and histologic examination of lymph node in establishing the diagnosis of cat-scratch disease.

Adolescent↗
PubMed1983

Cat scratch disease: a bacterial infection.

Histopathologic examination of lymph nodes from 39 patients with clinical and pathological criteria for cat scratch disease revealed delicate pleomorphic Gram-negative bacilli in 34 of the 39 nodes. They were within the walls of capillaries in or near areas of follicular hyperplasia and within microabscesses. They were best seen with the Warthin-Starry silver impregnation stain. Organisms in lymph node sections exposed to convalescent serum from three patients and to immunoperoxidase stained equally well with all three samples. The organisms did not react with hyperimmune sera to Legionella pneumophila nor to several species of Rickettsia. These bacilli appear to be the causative agents of cat scratch disease.

Cat-Scratch Disease↗
PubMed1982

Macrophage and lymphocyte contributions in resistance of Candida albicans infections.

Model in vivo and in vitro experimental systems have been used to study the efficacy of specific and nonspecific immunization against Candida albicans infection induced in mice. Experiments were designed to compare the extent of resistance in specificity immunized, endotoxin treated and saline treated animals. In vitro phagocytic and postphagocytic killing (cytopepsis) of macrophages or lymphocyte-macrophage combinations from such animals were determined. In the in vitro experiments the macrophage systems destroyed the yeast cells more rapidly than did the lymphocyte-macrophage combinations. Since equivalent numbers of yeast cells were phagocytized, the differences observed were a function of cytopepsis of the organisms.

Animals↗
PubMed1979

The effect of anticancer therapy on peripheral blood T and B lymphocyte counts and function.

Patients categorized according to tumor type were compared to a control non-tumor population. Comparison of relative T cell values among the groups showed no significant differences; however, when absolute numbers of T cells/mm3 were compared, all cancer patients, whether from treated or untreated groups, had significantly depressed T cell values. No significant differences were observed in the relative or absolute numbers of B cells. Comparison of the total lymphocyte response to PHA showed no significant differences among the various cancer groups; however, response in all cancer groups whether from treated or untreated patients, was depressed by comparison to the control group. Patients categorized according to the type of treatment received showed significant depression in the white blood count, lymphocyte count, relative and absolute T cell counts and the absolute B cell count in the postsurgery, postadjunctive therapy group. The pretherapy group also showed significant depression in the absolute number of T cells/mm3 when compared to the controls. Response to PHA correlated with the absolute T cells values.

Antineoplastic Agents↗