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Biomedical subjects

D Armstrong

Publications and source records attributed to D Armstrong.

At least 631 records · Page 35Linked to original sources
PubMed1977

Detection of canine Batten disease with the EEG.

Although it has been suggested that EEG changes appear early in the course of human Batten disease, these observations have been made only after the onset of clinical abnormalities and without immediate pathological correlation. In this brief report we have been able to document for the first time, abnormal EEGs in a strain of dogs proposed as a model for Batten disease. The degree of abnormality in the canine EEG correlated with the degree of clinical involvement and with the presence of pathological inclusions, resembling those seen in human Batten disease. In younger dogs, abnormal EEGs were obtained even before clinical manifestations of the disease. The large amplitude discharges reported with photic stimulation in children with the late infantile form of Batten disease were not elicited in the dog model. However, this dog strain is a model for the juvenile rather than the late infantile form although similarities between dogs and both forms of human Batten disease were seen. It is proposed that the EEG is both a method for early detection of this disease as well as a tool ot measure the degree of involvement. This information may be of use in relation to future therapeutic trials.

Animals↗
PubMed1977

Corynebacterium equi infection complicating neoplastic disease.

Corynebacterium equi, a soil-residing diphtheroid pathogenic in horses, swine and cows, caused pulmonary infection with bacteremia in two patients with lymphomas. Both patients were being treated with immunosuppressive therapy, as were the patients in three previously reported human cases. Unless certain characteristics of these organisms are recognized, they may be regarded as normal flora or contaminating diphtheroids. They could also be mistaken for other gram-positive rods, such as Bacillus species, Listeria monocytogenes, or Erysipelothrix insidiosa. C. equi isolates have usually been sensitive to erythromycin, tetracycline, gentamicin, and carbenicillin. One of the patients reported here was successfully treated with erythromycin, tetracycline, and surgery.

Corynebacterium Infections↗
PubMed1977

Thymidine-dependent strain of Salmonella oslo selected by trimethoprim-sulfamethoxazole therapy.

A case report describing the isolation of a multiple-drug-resistant strain of Salmonella oslo from urine and stool specimens is presented. After ten days of trimethoprim-sulfamethoxazole therapy, a second strain of Salmonella oslo was isolated from another stool specimen. The second strain was determined to be a thymidine-requiring organism. The significance of this thymidine-requiring strain is described.

Adult↗
PubMed1977

Immunodiffusion and agglutination tests for Candida in patients with neoplastic disease: inconsistent correlation of results with invasive infections.

A serological study of candidiasis was conducted with use of (1) sera sent to the laboratory by clinicians who suspected infections due to various organisms including Candida species, and (2) sera available in our serum bank from patients with candidiasis proven at autopsy and from those with documented candidemia. With this population of patients, we were able to evaluate both potential false-negative and false-positive results. Microimmunodiffusion and slide agglutination tests were used. In many cases, serial specimens were available for measurement of rises or falls in titers of agglutinating antibody. Sera from less than one-half of the patients with disseminated or invasive gastrointestinal candidiasis exhibited positive immunodiffusion reactions, titers of agglutinating antibody of greater than 1:16, or fourfold rises in titer of agglutinins. Sera from several patients with pharyngitis due to Candida and from several who were only colonized with Candida or for whom clinical or cultural evidence of candidiasis was lacking showed positive immunodiffusion reactions or agglutinin titers of greater than 1:16, and some showed fourfold rises in titer. Conversions from negative to positive immunodiffusion reactions were not consistently correlated with invasive candida infection. Using the methods described, we have not found immunodiffusion tests and titers of agglutinating antibody to be reliable indicators of invasive candida infection, since false-positive as well as false-negative reactions occur. Greater specificity for invasiveness as well as greater sensitivity in immunosuppressed patients are necessary before these tests can become important adjuncts to the evaluation of patients with suspected invasive candidiasis.

Adolescent↗
PubMed1977

The structure of medical education.

The recurrent failure to adequately conceptualize the medical meaning of 'diease' is explained as a function of the way this is taught in the curriculum. It is not transmitted within the formal curriculum but within the internal structural relationships of the medical course. The limits of this particular definition engendered during medical education are described, and it is concluded that curriculum reform which stresses change in content and neglects educational structure will fail to modify this notion of disease.

Curriculum↗
PubMed1977

Rapid microdilution-colorimetric assay for yeast susceptibility to fluorocytosine.

Acid production by certain yeast species through the fermentation of glucose was used as the basis of an in vitro test for measuring susceptibility of these organisms to 5-fluorocytosine. Serial dilutions of 5-fluorocytosine in yeast nitrogen base broth, with bromothymol blue indicator dye, were made on microtiter plates. A fixed-concentration suspension of yeast cells was added to successive wells of the plates, and the color change from blue to yellow, indicating generation of acid, was noted. Eighteen hours after inoculation the lowest concentration of 5-fluorocytosine that completely inhibited the production of acid was recorded as the minimum inhibitory concentration. The results were reproducible in multiple trials with organisms of the genera Candida, Torulopsis, and Saccharomyces. This test is a rapid, inexpensive alternative to current 48- to 72-h methods in which broth turbidity is used as the end point.

Candida↗
PubMed1977

Comparative serological and cutaneous reactivity of candidal cytoplasmic proteins and mannan separated by affinity for concanavalin A.

Yeast-form Candida albicans cells were disrupted for 1.5 min in a Braun homogenizer and centrifuged at 100,000 X g. The supernatant was concentrated by ammonium sulfate precipitation and then dialyzed. The resulting material (650 mg), containing 81.2% protein and 11.5% carbohydrate, was subjected to affinity chromatography on concanavalin A (Con A) linked to agarose. A protein fraction was eluted from the column with buffer, and a fraction containing mannan was eluted with 0.2 M alpha-methyl mannoside. The candidal soluble proteins had 19 components which were resolvable by polyacrylamide gel electrophoresis. The material with affinity for Con A contained mannan and 17% complexed protein. Antigenic differences between the soluble proteins and the mannan-protein complex were shown by lines of intersection in immunodiffusion. The soluble proteins devoid of mannan reacted in immunoelectrophoresis with sera from infected rabbits and patients with chronic candidiasis. These same sera also reacted with a mannan-protein complex eluted from the Con A column with alpha-methyl mannoside. The comparative ability of candidal proteins and cell wall-derived mannan to elicit skin test reactions in guinea pigs sensitized by infection or with formaldehyde-killed yeast was studied. Candidal proteins at a 10-mug dose elicited positive reactions at 6 and 21 days after sensitization. The reactions persisted for 48 h and showed minimal tendency to an arthus response, which was marked when mannan-containing antigens were used. The antigenicity of cell wall-derived mannans and candidal soluble proteins devoid of mannan was compared in immunodiffusion tests of sera from 39 patients with neoplastic disease. Of these patients with documented candidiasis, 13 of 20 reacted to one or more mannan antigens, and 3 of 20 reacted to candidal soluble proteins. In contrast, of those patients who were uninfected or had superficial Candida spp. infections, 5 of 19 reacted to candidal soluble proteins, and 16 of 19 reacted to one or more mannan antigens.

Animals↗
PubMed1977

Diagnosis of Batten disease from urinary sediment: a brief report.

Urinary sediment from a patient with the juvenile form of Batten disease was examined by electron microscopy. Membrane bound fingerprint profiles were found which were similar to those previously described in a biopsy from this patient's thyroid gland. These findings might represent a useful diagnostic tool.

Humans↗
PubMed1977

Infectious syphilis mimicking neoplastic disease.

Five patients who were initially evaluated for malignant neoplasm actually had infectious syphillis (one primary, two secondaries, two secondaries with persistence of primary). Two patients were considered for radical surgery and one for extensive radiation and/or chemotherapy. In four patients an elevated routine admission VDRL was the first indication of the correct diagnosis. Dark-field examination is the most important laboratory test in the diagnosis of primary syphillis; VDRL and FTA-ABS are most important in confirming secondary syphillis. Penicillin remains the drug of choice for therapy. At a time when the incidence of sexually transmitted diseases is increasing, it is extremely important to develop adequate educational programs for medical students and physicians.

Adult↗
PubMed1977

Decreased amniotic fluid peroxidase in malignancy of the cervix.

Studies of amniotic fluid obtained at various times throughout the last trimester of pregnancy from patients with carcinoma of the cervix indicate a complete deficiency of peroxidase activity. Dialysis partially restores the enzyme activity. Cervical epithelial tumor cells apparently release a dialyzable, low molecular weight inhibitory substance directed specifically toward peroxidase. If this proves to be true in future studies, the peroxidase assay could be a sensitive means of differentiating between carcinoma and dysplasia. A peroxidelike substance was also present in the amniotic fluids obtained from patients with carcinoma. Other investigators have demonstrated large amounts of peroxide in malignant tumors. These elevated peroxide levels might well be directly related to deficient peroxidase activity rather than being a result of other abnormal enzyme levels which have been regarded as being principally involved in the metabolism of this highly toxic molecule.

Amniotic Fluid↗
PubMed1976

Salmonella oslo. A focal outbreak in a hospital.

Five patients were infected with a nontyphosal Salmonella species, Salmonella oslo. Three of the five patients had undergone endoscopy. Three possibilities existed to account for this outbreak: the positive cultures represented isolated events; there was one isolated event and a common source; or, all events were due to a common source. The results of our investigation were inconclusive, but suggested that the endoscope could have been responsible for some of the cases. Appropriate methods for sterilizing endoscopes are reviewed, including sterilization with 2.5 per cent glutaraldehyde solution and ethylene oxide gas. The organism was unusual in its resistance to chloramphenicol and ampicillin; however, it was sensitive to a sulfonamide and trimethoprim. Two patients became culture-negative for S. oslo on treatment with this combination.

Adult↗