Biomedical subjects
Publications and source records attributed to H L Thacker.
For most menopausal women, the benefits of hormone replacement therapy outweigh the risks, despite the fears aroused by the unproven link to breast cancer. If the goal is solely to relieve menopausal symptoms, the treatment duration is generally 2 to 3 years and then gradually tapered off. If the goal is to provide cardiac protection and prevent osteoporosis, long-term, possibly lifetime, treatment is needed.
OBJECTIVE: To describe the course of the eosinophilia-myalgia syndrome during a 2-year period. DESIGN: 15 physicians completed a structured review form to describe symptoms, physical findings, laboratory data, and responses to treatments in 205 patients with the eosinophilia-myalgia syndrome at the onset of illness and after 18 to 24 months of follow-up. SETTING: 15 university and private clinical practice settings. PATIENTS: 205 patients for whom follow-up data were available and who met four criteria at diagnosis: eosinophil count of 1000 cells/mm3 or greater; presence of fasciitis, peripheral neuropathy, polyradiculopathy, interstitial pulmonary disease, pulmonary hypertension, or myocardial involvement; history of L-tryptophan consumption; and absence of other conditions that could account for these findings. INTERVENTION: Empirical interventions by the physicians. MEASUREMENTS: Symptoms, physical findings, laboratory test results, biopsy findings, radiographic reports, therapeutic interventions, and responses to these interventions. RESULTS: After 18 to 24 months, all symptoms except cognitive changes were reported to have improved in most patients. Nearly all physical findings were also reported to have improved or resolved in most patients; only peripheral neuropathy was unchanged. No evidence of ongoing inflammatory disease was reported. Prednisone was reported to be helpful in 79% of patients who received it during the acute phase of the syndrome. No other treatment was reported to be consistently beneficial. CONCLUSIONS: 18 to 24 months after the onset of illness, most symptoms and physical findings in most patients with the eosinophilia-myalgia syndrome resolved or improved. Cognitive changes were reported to be worse in 32% of patients. Prednisone was helpful in the acute phase of illness. No treatment was clearly valuable in management of the later phase of the syndrome.
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A retrospective study of 256 cases of naturally acquired Streptococcus suis infections in swine submitted to the Indiana Animal Disease Diagnostic Laboratory from 1985 to 1989 was undertaken to describe the clinical signs, lesions, and coexisting organisms associated with S. suis serotypes 1-8 and 1/2. Infected pigs generally had clinical signs and gross lesions referable to either the respiratory system or to the central nervous system (CNS), but not both. Neurologic signs were inversely related to gross lesions in the respiratory tract (R2 = -0.19, P = 0.003), as were respiratory signs and gross lesions in the CNS (R2 = -0.19, P = 0.003). Suppurative bronchopneumonia was the most common gross lesion observed (55.2%, overall). Fibrinous and/or suppurative pleuritis, epicarditis, pericarditis, arthritis, peritonitis, and polyserositis were also reported. In 68% of the pigs, other bacteria in addition to S. suis were isolated. Escherichia coli (35.0%) and Pasteurella multocida (30.0%) were the most commonly recovered bacterial agents. Mycoplasma and viral agents were identified less often, and their role in the development of streptococcosis was difficult to assess. In pigs infected with serotypes 2-5, 7, 8, and 1/2, suppurative meningitis with suppurative or nonsuppurative encephalitis, suppurative bronchopneumonia, fibrinopurulent epicarditis, multifocal myocarditis, and cardiac vasculitis were the most common microscopic lesions observed, whereas pigs infected with serotype 1 generally presented with suppurative meningitis and interstitial pneumonia. Microscopic lesions were morphologically similar among serotypes and were also similar to those reported with other pyogenic bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)
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A retrospective study of 256 cases of naturally acquired Streptococcus suis infections in swine submitted to the Indiana Animal Disease Diagnostic Laboratory from 1985 to 1989 was performed to determine the epidemiologic factors and antibiotic susceptibility patterns associated with S. suis serotypes 1-8 and 1/2. A standardized computer form was used to record the history, signalment, and clinical signs obtained from the records of selected cases and the microscopic lesions identified after review of the histopathology slides for each case. A computer statistics package (SAS) was used to evaluate the data. Although the number of recovered S. suis isolates increased in the fall and winter months, most serotypes were readily isolated throughout the year; only serotypes 1, 4, 7, and 1/2 increased in frequency of isolation in the fall, winter, and spring months. The majority (61.1%) of infected pigs in this study were < 12 weeks of age. More than 75% of pigs infected with serotypes 1, 6, 7, and 1/2 were < 12 weeks of age. There was extensive overlap in the age distributions for pigs with each serotype, and statistically significant differences for most serotypes were not observed. Fifty percent of pigs infected with S. suis serotypes 1 and 1/2 were 3-10 weeks of age, 50% of pigs infected with serotype 2 were 6-14 weeks of age, and 50% of pigs infected with serotypes 3, 4, 5, 7, and 8 were 2-16 weeks of age. Isolates of S. suis were not uniformly susceptible to penicillin, and a large percentage of isolates were resistant to many antibiotics in common usage.(ABSTRACT TRUNCATED AT 250 WORDS)
The aging cardiovascular and renal systems put the elderly patient at increased risk of end-organ damage from marked hypertension. Thus, the office-based physician needs to be skilled in making the diagnosis of a hypertensive urgency or emergency based on accurate blood pressure readings and an assessment of the heart, brain, retina, and kidney. Hypertension urgency and emergency are distinguished from each other by the clinical decision of how quickly the blood pressure must be lowered. The clinician has a wide variety of agents from which to choose for pharmacologic treatment, with the goal being a smooth and safe reduction in blood pressure.
The pathologic response of the lung to irritant gases ranges from the acute exudative phase through the subacute proliferative phase to the chronic fibrosing phase. These responses are based on damage to the Type I cells, and possibly endothelial cells, and the subsequent proliferative and repair processes in the surviving animals. Responses to high dose exposures appear at the microscopic level as exudation of protein rich fluids into alveoli (alveolar edema) and subsequent death due to anoxia. Physiologically, this could be described as a mismatch of ventilation with perfusion, resulting in impaired gas exchange. Animals surviving this acute exudative phase resolve the alveolar edema to fibrin, and Type II cells become hypertrophic and hyperplastic in the process of replacing the damaged Type I cells. The acute and subacute responses also elicit inflammatory changes in the interstitium of the lung that may progress to fibrosis in the chronic stage of a survivable exposure. Diagnostic cases in livestock involving irritant gases reflect similar toxic injuries to the lung.
Systemic infection of mature beef cows with Salmonella typhimurium resulted in death of cows, abortions, and premature births. Salmonella typhimurium was isolated from the kidney, liver, and spleen of cows but not from an aborted fetus. Diarrhea was not a prominent clinical feature of the epizootic. The source of the salmonella was not determined.
Infection with larvae of Baylisascaris procyonis, the raccoon ascarid, was the cause of neurologic disease affecting young pheasants on a commercial pheasant ranch in Wisconsin. The disease was chronic and insidious, affecting 1% to 2% of the birds over a period of 2 years. Histologic lesions in the brain consisted of multifocal areas of necrosis and inflammation associated with Baylisascaris larvae. Onset of the disease at the farm correlated with introduction of chopped straw as bedding for the young birds. The straw was from a neighbor's barn and was contaminated with raccoon feces that contained B procyonis eggs. Cessation of use of the contaminated straw resulted in cessation of CNS disease in pheasants on the ranch.
A procedure for performing a thorough necropsy examination of feeder pigs or adult swine is presented. Lesions encountered in various organ systems due to various disease states are included, along with those changes of inconsequential or artifactual status.
Twenty-six 4-week-old pigs were randomly allotted to 4 groups: group 1--orally inoculated with Salmonella typhimurium; group 2--orally dosed with S choleraesuis; and groups 3 and 4, with surgically constructed intestinal loops--loops inoculated with either S typhimurium or S choleraesuis. One pig each from groups 1 and 2 was killed at 8, 12, 24, 48, 72, 96, and 120 hours after inoculation. One pig each from groups 3 and 4 was killed at 2, 4, 6, 8, 12, and 24 hours after intestinal loop inoculation. Inoculation of S typhimurium resulted in acute enterocolitis of variable severity, whereas inoculation of S choleraesuis resulted initially in septicemia followed by formation of large necrotic and ulcerative lesions in the colonic mucosa. The most consistent systemic lesion of S choleraesuis infection was interstitial pneumonia and multifocal hepatic necrosis. Salmonella typhimurium and S choleraesuis were ultrastructurally within enterocytes of ligated ileal loops. Intracellular bacteria were morphologically intact, occurred free in the cytoplasm and membrane bound, and caused no detectable cytotoxic effect to the cell. Both S typhimurium and S choleraesuis penetrated the intestinal mucosa and were isolated from mesenteric lymph nodes at 2 hours after inoculation.
One hundred and twenty female mice (CF1 strain) were divided into three groups of 40. The first group was injected intraperitoneally with broth cultures of Treponema hyodysenteriae. The second group was injected with a combination of T. hyodysenteriae and Bacteroides vulgatus. The third group was injected with Treponema innocens. Peritoneal wash from four mice of each group was collected at eight time intervals postinjection, then prepared for and examined by light and electron microscopy. Peritoneal wash from one mouse at each time interval was prepared for microbiological examination. Treponema hyodysenteriae produced peritoneal macrophage aggregation, transient neutrophilia and macrophage cytolysis. Cytolysis was characterized by rarefaction of the cytoplasm, vesiculation of the endoplasmic reticulum, mild swelling of the mitochondria and disruption of the nuclear and ctyoplasmic membranes. The combination of T. hyodysenteriae and B. vulgatus produced macrophage aggregation and marked neutrophil necrosis. Peritoneal macrophages phagocytized more T. hyodysenteriae than B. vulgatus during early postinjection intervals. Treponema innocens failed to produce cytotoxicity of peritoneal macrophages but did produce macrophage aggregation and transient neutrophilia. Treponema hyodysenteriae and T. innocens did not multiply in the mice peritoneal cavity and were reisolated up to 16 hours postinjection. Bacteroides vulgatus was reisolated up to 24 hours postinjection.
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Avian pox virus was isolated from cutaneous pox lesions removed from turkey breeders that had been vaccinated three times with a commercial fowl pox vaccine. In three cross-immunization experiments with turkeys and two with chickens, the turkey pox isolate, designated NC5271, proved immunologically different from fowl, pigeon, and quail pox viruses. Significant protection against NC5271 virus infection and inducement of pox lesions was only attained when the homologous isolate was used as a vaccine. The potential need in the field for such a vaccine was discussed.
At 4 days of age, 7 gnotobiotic pigs were orally inoculated with broth cultures of both Campylobacter sputorum subsp mucosalis (CSM) and Campylobacter hyointestinalis (CH). One pig was killed and evaluated each week for 7 weeks. Forty-eight hours after inoculation, CH and CSM were recovered from the feces of the pigs; thereafter, only CH was recovered. Organisms morphologically typical of Campylobacter sp were observed on the mucosal surface and on the crypt epithelial cells of the ileum, cecum, and colon from post-inoculation weeks (PIW) 2 through 7. Bacteria were clustered around the surface opening of goblet cells in pigs at PIW 6 and 7. Crypt epithelial cell proliferation and intracellular bacteria were not seen, except in 1 pig (killed at PIW 7) in which intracellular bacteria were seen only in the cecum. Therefore, CSM and CH did not induce porcine proliferative enteritis in gnotobiotic pigs.