Search PubMed⌕ Search

Biomedical subjects

D Armstrong

Publications and source records attributed to D Armstrong.

At least 505 records · Page 28Linked to original sources
PubMed1985

Infections caused by Mycobacterium avium complex in immunocompromised patients: diagnosis by blood culture and fecal examination, antimicrobial susceptibility tests, and morphological and seroagglutination characteristics.

The Mycobacterium avium complex, only rarely described as an invasive pathogen in humans, has recently been reported to frequently cause disseminated disease in patients with the acquired immune deficiency syndrome. Between February 1981 and February 1984 at Memorial Sloan-Kettering Cancer Center, 30 patients with acquired immune deficiency syndrome, 3 patients with leukemia, and 2 patients with congenital severe combined immunodeficiency syndrome developed disseminated M. avium complex infection. Mycobacteria were often found in multiple sites both antemortem and postmortem. Blood cultures were a reliable method for detecting disseminated infection, and the new lysis blood culture systems provided an efficient technique for determining the number of organisms per milliliter of blood. Acid-fast stains and cultures of fecal specimens were also helpful in diagnosing infection. Most of the mycobacteria were serovar 4 (77%), and most (86%) produced a deep yellow pigment. All isolates were susceptible to standard concentrations of clofazimine, cycloserine, and ansamycin, but tended to be resistant to isoniazid, streptomycin, ethambutol, ethionamide, and rifampin.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Catheter-associated fungemia caused by Fusarium chlamydosporum in a patient with lymphocytic lymphoma.

A case of catheter-associated fungemia caused by Fusarium chlamydosporum is described in a patient with lymphocytic lymphoma. The fungus, which has been isolated from soil but not reported to cause human infection, characteristically produces microconidiophores that are polyphialides bearing microconidia that are spindle-shaped but never globose. Results of in vitro antimicrobial susceptibility tests depended on the test conditions used.

Adult↗
PubMed1985

Evaluation of the Quantum II yeast identification system.

We compared three methods for identifying clinical yeast isolates: Abbott Quantum II, API 20C, and a modified BBL Minitek system. The API 20C and modified Minitek systems agreed on the identification of 243 of 245 yeasts (99.2%). The Quantum II system correctly identified 197 (80.4%), incorrectly identified 19 (7.8%), and did not identify 29 (11.8%) of the yeasts. Most of the misidentifications with the Quantum II occurred because assimilation or biochemical results were false-positive. Sixteen different species of yeasts and 16 different Quantum II substrates contributed to the discrepancies. On retesting with the Quantum II, 31% of the discrepant strains were correctly identified, while the remaining 69% were incorrectly identified or were not identified. Erroneous biochemical and assimilation results were also noted with yeasts that were correctly identified by the Quantum II system.

Candida↗
PubMed1985

Retinal pigment epithelial dysfunction in early ovine ceroid lipofuscinosis: electrophysiologic and pathologic correlates.

Retinal degeneration is a major finding in the human and ovine ceroid lipofuscinosis. Sequential electroretinographic (ERG) studies in a young, asymptomatic, affected lamb are presented here, which demonstrate a progressive loss of the scotopic b-wave and unrecordable c-waves under halothane anesthesia. Even at this initial stage of disease, lesions were evident in the form of dystrophic retinal pigment epithelial (RPE) villi, and loss of photoreceptor cells and rod outer segments. Cone inner segments were enlarged and scanning electron microscopy emphasized these abnormalities. All cells in tapetal and nontapetal areas contained fluorescent inclusions with similar emission spectra (maximum = 539 nm). By transmission electron microscopy, storage bodies consisted of 'finger-print' profiles and were most prominent in bipolar cells. The pathological features of the retina correlate well with the observed ERG changes, reaffirming the sheep as a useful model to delineate early events in ceroid lipofuscinosis.

Animals↗
PubMed1985

Salmonella infections in patients with the acquired immunodeficiency syndrome.

Defects in T-cell function have been seen in patients with the acquired immunodeficiency syndrome. Although the cellular immune system plays a key role in host defense against Salmonella, there have been no detailed reports of salmonellosis in patients with this syndrome. We report our experience with salmonella infections in six patients. Salmonellosis in these patients was unusually severe, characterized by widespread infection, bacteremia, and relapse, despite standard antibiotic treatment. Because of the difficulty in eradicating salmonella infection in patients with the acquired immunodeficiency syndrome, long-term suppressive treatment with antibiotics seems warranted.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Treatment of infections in patients with the acquired immunodeficiency syndrome.

The microorganisms that regularly infect patients with the acquired immunodeficiency syndrome (AIDS) have become well recognized. Most take advantage of defects in T-lymphocyte function, but others, such as Streptococcus pneumoniae and Haemophilus influenzae, take advantage of B-cell defects. Still others, such as Staphylococcus aureus and Shigella species, occur or persist for reasons that are unclear. Infections with organisms associated with hospitalization and medical procedures are also seen and should be anticipated. Among the infections taking advantage of T-cell defects, Pneumocystis carinii pneumonia is the most commonly diagnosed, but cytomegalovirus infection may be equally common. Disseminated Mycobacterium avium-intracellulare infection has been found in one half of our patients at postmortem examination. The retrovirus responsible for AIDS commonly infects the central nervous system, as does Toxoplasma gondii. Although candida infections are common, dissemination is uncommon. Many of the infections respond to appropriate therapy but tend to recur when treatment is stopped. Often treatment courses must be prolonged even beyond those used in other immunocompromised hosts.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Sea-blue histiocytes in canine ceroid-lipofuscinosis (CCL).

Cells corresponding to sea-blue histiocytes are described in bone marrow aspirates from dogs suffering hereditary ceroid-lipofuscinosis. Sea-blue histiocytes also occur in humans with so-called neuronal ceroid-lipofuscinosis and both exhibit strong autofluorescence. By quantitative fluorometric techniques, each species have similar spectral characteristics and, thus, the English setter with CCL can serve as a useful animal model.

Animals↗
PubMed1985

Influence of cell proliferation on initiating activity of pure polychlorinated biphenyls and complex mixtures in resistant hepatocyte in vivo assays for carcinogenicity.

The abilities of various pure polychlorinated biphenyls (PCB) and complex mixtures to generate resistant gamma-glutamyltransferase (GGT)-positive hepatocellular nodules was evaluated in F344 rats in which hepatocytes were proliferating. The PCB examined were 2,2',4,4',5,5'-hexachlorobiphenyl (CAS: 35065-27-1), 2,2',4,4'-tetrachlorobiphenyl, 2,2',5,5'-tetrachlorobiphenyl, Aroclor 1254 (CAS: 11097-69-1), and a prepared mixture of pure PCB isomers and congeners similar to those found in human breast milk. The PCB were administered either to male and female suckling rats (weekly for 3 wk) during liver growth or to adult male rats (150-160 g body wt) previously subjected to two-thirds partial hepatectomy (PH). Rats were subsequently given a selection regimen consisting of 3 daily doses (20 mg/kg) of 2-acetylamino-fluorene (2-FAA; CAS: 53-96-3) followed by either PH or necrotizing carbon tetrachloride (CAS: 56-23-5) in adult rats that previously underwent PH. None of the PCB exposures generated GGT-positive nodules after selection, whereas known initiators such as diethylnitrosamine (CAS: 55-18-5), 3-methylcholanthrene (CAS: 56-49-5), benzo[a]pyrene (CAS: 50-32-8), and 2-FAA were active initiators of nodules in suckling or hepatectomized rats. These findings indicate that short-term exposures to these PCB during liver cell proliferation do not show initiating action in an in vivo assay that detects both hepatic and nonhepatic initiating carcinogens.

Animals↗
PubMed1984

Staphylococcus epidermidis septicemia in children with leukemia and lymphoma.

Staphylococcus epidermidis is emerging as a cause of morbidity and mortality in immunocompromised patients. From January 1980 through June 1982, there were 150 episodes of septicemia in 92 children with leukemia and lymphoma at Memorial Sloan-Kettering Cancer Center, New York. Staphylococcus epidermidis was the fourth most common organism isolated, responsible for 12.7% of all septicemic episodes. Only nine of 53 isolates were sensitive to methicillin; all were sensitive to vancomycin. Staphylococcus epidermidis septicemia was associated with immunosuppressive chemotherapy (94.7%); broad-spectrum antibiotics (79.0%); catheters and drains (73.7%); neutropenia (63.2%); skin or soft-tissue infections (42.1%); prior septicemia (42.1%); concurrent polymicrobial septicemia (21.1%); and prolonged hospitalization (mean, 39 days). Of 19 patients, two died. Increased awareness of the pathogenic potential of S epidermidis in children with hematologic malignancies and prompt alteration of therapy to an effective antimicrobial agent, in most cases vancomycin hydrochloride, is required when the organism is isolated in patients known to be at risk with clinical evidence of septicemia.

Adolescent↗
PubMed1984

Central nervous system infections in the immunocompromised host.

Central nervous system (CNS) infections in the immunocompromised host are predictable according to the arm of the immune defense which is most defective. A limited number of organisms with a tendency to cause CNS infections will take advantage of the different types of immune defects. Signs and symptoms of CNS infection are often quite subtle in the immunocompromised host because of the diminished inflammatory response. Serologic responses may not be as reliable as in a normal host. Aggressive diagnostic approaches are often necessary, including early brain biopsy and abscess drainage. Aggressive therapy is often also necessary, including multiple potentially toxic antibiotics and devices to deliver them, such as indwelling intraventricular reservoirs. The role of the third generation cephalosporins is still not clear, and certainly they should not be used alone to treat aerobic gram-negative rod meningitis in neutropenic patients. Patients with the acquired immune deficiency syndrome (AIDS) have developed CNS infections with familiar agents producing familiar syndromes. The main CNS infection, however, is a subacute encephalitis and the causative agent remains undocumented.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Symposium on infectious complications of neoplastic disease (Part II). Protected environments are discomforting and expensive and do not offer meaningful protection.

An environment that is germ free and a patient who is germ free have been goals in managing immunocompromised patients, especially those who are neutropenic. Such a germ-free environment, inside and out, can be achieved in laboratory animals after considerable manipulation, including delivery by cesarean section. This is rarely indicated or achieved in humans, but investigators have tried to decrease the numbers of organisms on the outside of patients (both environmental and on the skin) and to do the same with the inside--or at least to selectively decrease the organisms most likely to invade from mucous membranes and the gastrointestinal tract. Most studies of protected environments have included patients who receive prophylactic oral nonabsorbable antibiotics, prophylactic systemic antibiotics, or oral absorbable antibiotics (selective decontamination). Another variable that needs to be considered is the use of sterile food--included in some studies, not used in others, and not mentioned in still others. No studies have used the only appropriate control, which is the same laminar airflow room, but with the airflow turned off and without gowns, masks, or gloves, only assiduous hand-washing. The same staff should care for the control patients as well as those in protected environments. In addition, control patients in some studies have been clearly different in the severity of the underlying disease from patients placed in protected environments. Even without these proper controls, differences in infection rates have varied considerably among the studies both inside and outside the protected environment and efficacy has also varied considerably; however, the one constant in almost every controlled study is that life has not been prolonged, remission induction increased, nor remission duration prolonged.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1984

Oral trimethoprim/sulfamethoxazole in attempt to prevent infection after induction chemotherapy for acute leukemia.

The efficacy of orally administered trimethoprim/sulfamethoxazole for infection prevention following induction chemotherapy was evaluated in 43 patients with acute leukemia. Twenty patients were randomly assigned to treatment with trimethoprim/sulfamethoxazole during 20 episodes of profound granulocytopenia; 23 patients in the control group were followed through 25 granulocytopenic episodes. The incidences of superficial skin and overall infections were significantly lower in those patients with multiple relapses who received trimethoprim/sulfamethoxazole (p = 0.008); however, there was no difference between the groups in regard to days of fever, days of antibiotic administration, days of hospitalization, or gram-negative rod bacteremia. As a result of this study, this regimen cannot be unequivocally recommended for infection prevention in neutropenic patients with acute leukemia undergoing induction or reinduction chemotherapy.

Acute Disease↗
PubMed1984

Effect of l-dopa or bromocriptine on feeding and motor behavior of rats with lesions in the globus pallidus.

Rats were lesioned bilaterally in the globus pallidus (GP) with anodal current or 6-OHDA, and were observed in various motor tests 10 min daily for 3 weeks. Body weight, home cage water and food intakes were recorded daily under two different food accessibility conditions. The lesions produced adipsia, aphagia, loss of body weight and motor impairments which could not be reversed by either l-dopa or bromocriptine. Animals could be made to recover, however, by making food easily accessible and palatable. The results do not support a "metabolic" role for the GP but support the idea that aphagia, adipsia and mortality is due to motoric impairments produced by the lesion.

Animals↗
PubMed1984

The patient's view.

Deference to the importance of the patient's view has recently become a major feature of much medical practice and social science research. This paper, however, argues that attempts to establish the authentic version of what the patient says is misplaced as investigation can only reveal what is heard, not what is said. The changes in perception which enable some things to be heard, and not others, are traced through medicine and the social sciences during the last 50 years and it is suggested that recent interest in the validity of the patient's view are no more than artefacts of these changes in perception.

Attitude of Health Personnel↗
PubMed1984

Patient attitudes towards radiographic examinations involving contrast media.

Patient attitudes and responses to radiographic examinations with contrast media were measured by means of a self-administered questionnaire. Forty-seven per cent of patients reported being worried about its unpleasantness and 64% about its possible findings. Men expressed less anxiety about the unpleasantness than women and old people less about the findings than young people. Most patients, but especially those who were worried about the procedure, would have liked more information about why they were having the investigation; worried patients were also more likely to seek non-medical advice. There was, however, no difference between 'worried' and 'non-worried' patients in their understanding of the nature of the investigation.

Anxiety↗