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Biomedical subjects

A Levine

Publications and source records attributed to A Levine.

At least 127 records · Page 7Linked to original sources
PubMed1988

Production of a positive direct antiglobulin test due to suramin.

Drugs and chemicals containing multiple reactive carbonyl groups have been postulated to produce nonimmunologic positive direct antiglobulin tests (DATs) both in vitro and in vivo. Suramin sodium, a reverse transcriptase inhibitor that was under investigation as a potential treatment for human immunodeficiency virus infection, has six reactive carbonyl groups. Because of suramin's chemical structure, it was hypothesized that the drug might cause a positive DAT in vitro and possibly in vivo. Suramin was found to produce a positive DAT in vitro at concentrations of 2100 mg/L or greater but did not cause a positive DAT in five patients with acquired immunodeficiency syndrome who were treated with suramin, probably because the serum levels of suramin were too low in these patients (peak therapeutic blood levels ranged from 171 to 443 mg/L).

Acquired Immunodeficiency Syndrome↗
PubMed1987

Chromosomal initiation in Bacillus subtilis may involve two closely linked origins.

When the dnaB37 initiation mutant of Bacillus subtilis is returned to a permissive temperature following a period at 45 degrees C, a synchronous round of DNA replication immediately ensues. Using this system we have been able to analyse the first fragments to be replicated while avoiding the use of thymine starvation or inhibitors of DNA replication. Such treatments are necessary to achieve even modest synchrony in germinating spores. Our results showed that the first fragment to be replicated was a 4 kb BamHI-SalI restriction fragment, BS6. In contrast, when the analysis was performed out in the presence of novobiocin, an inhibitor of DNA gyrase, replication from BS6 was inhibited and the first fragment to be replicated was BS5, a 5.6 kb fragment located 1.7 kb to the right of BS6. Replication from both putative origins was suppressed by rifamycin and was dependent upon dnaB. The results are discussed in relation to previous attempts to identify the first replicating fragment in germinating spores. We also discuss the possibility that B. subtilis contains two origins and suggest that either can act as the primary origin under certain conditions, or alternatively that both origins may act in concert in normal bidirectional replication, each site being required for the leading strand in each direction.

Bacillus subtilis↗
PubMed1987

Isoflurane induces coronary steal in a canine model of chronic coronary occlusion.

The hypothesis that isoflurane causes coronary steal was investigated in a canine model of chronic coronary occlusion. An ameroid constrictor was implanted in dogs to stimulate the development of intercoronary collateral vessels. During an acute experiment 3-4 weeks following implantation, heart rate, mean arterial pressure, and total coronary flow were held constant, and flow distribution was measured with microspheres in the presence and absence of isoflurane. Contractile function of the collateral-dependent zone and myocardial lactate extraction were also measured. Isoflurane produced a decrease in collateral flow and a decrement in collateral zone contraction, while, at the same time, enhancing flow in the normally perfused zone. In a second series of animals, isoflurane was found to have effects similar to those of adenosine, an arteriolar dilator known to produce coronary steal. In contrast, neither halothane nor nitrous oxide caused flow alterations or dysfunction of the collateral-dependent zone.

Adenosine↗
PubMed1986

Initial manifestation of acquired immunodeficiency syndrome in the head and neck region.

Initial manifestation of AIDS in the head and neck region occurs frequently. The purpose of this report has been to alert the head and neck surgeon to the occurrence of AIDS-related lesions, their clinical characteristics, and disease outcome. Incomplete recognition of these disorders may delay appropriate diagnostic study and initiation of therapy. We have described 10 patients in whom the initial manifestation of AIDS-related malignancies occurred in the head and neck region. Six of these patients were found to have Kaposi's sarcoma, whereas four had non-Hodgkin's lymphomas. The specific clinical and pathologic aspects of the disease have been described, which represent common patterns of presentation. It is crucial to obtain an accurate social history, as well as a complete medical history from any patient suspected of having AIDS, and prompt biopsy of suspect lesions should be performed.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Role of health locus of control beliefs and expectations of treatment efficacy in adjustment to cancer.

We examined the effects of health locus of control beliefs (self-, doctor, and chance control) and expectations of treatment efficacy on short-term psychological adjustment in a sample of newly diagnosed cancer patients. The role of these beliefs and expectations in moderating the relation between (perceived and actual) disease severity and depression was also examined. The data were collected within one week of diagnosis. The relation between perceptions of disease severity and depression was weaker for those who believed that they could personally control their health and for those who held positive expectations about the effects of complying with medical treatment. Similar patterns were found when disease severity was defined in terms of prognosis for survival. Strong negative correlations between self-control/treatment expectations and depression were found for those who perceived that their illness was very severe. The results for chance and doctor control were less consistent. The stability of health control beliefs and treatment expectations over the course of a serious long-term illness is discussed.

Adaptation, Psychological↗
PubMed1986

Acute leukemias with both myeloid and lymphoid surface markers. Cytoplasmic alpha-1-anti-chymotrypsin and alpha-1-anti-trypsin as possible indicators of early granulocytic differentiation.

Blast cells from ten patients (seven adults, three children) with acute lymphoblastic leukemias (ALL) contained immunoreactive cytoplasmic alpha-1-anti-trypsin (alpha-1-AT) and alpha-1-antichymotrypsin (alpha-1-ACT). Cytochemically positive reactions for block-like periodic acid-Schiff and a localized acid phosphatase suggested that the cells were of lymphoid origin rather than myeloid origin: negative for sudan black-B, nonspecific esterase, chloroacetate esterase, and myeloperoxidase. By surface phenotype, the leukemia showed positive reactions for both lymphoid (common acute lymphoblastic leukemia antigen, Ia, OKT-10) and myeloid (OKM-1, Leu M-1) antigens. Three of three patients tested portrayed the Philadelphia chromosome. Nine patients were Mexican-American and one was Japanese: all were of Asian ethnic derivation. Both myeloid and lymphoid treatment regimens were employed, with survival less than expected. Early granulocytic differentiation detectable by cytoplasmic alpha-1-AT and alpha-1-ACT in lymphoid blasts is discussed.

Adult↗
PubMed1985

Kaposi's sarcoma in Los Angeles, California.

The demographic characteristics of "classic" Kaposi's sarcoma (KS) and of "epidemic" KS in Los Angeles, CA, were compared with the use of data from the Cancer Surveillance Program, the population-based tumor registry in Los Angeles County. The data obtained document the magnitude of the excess risk of classic KS for Jewish men of European (especially Eastern and Southern European) origin. The data also show in a systematic way the magnitude of the increase in acquired immune deficiency syndrome-related KS in one large urban area of the United States. In addition, they demonstrate that the demographic risk factors of religion and birthplace for classic KS are unrelated to epidemic KS and that the clinical presentation in terms of stage and primary site of classic KS is distinct from that of the epidemic form of the disease.

Adolescent↗
PubMed1980

Primary mediastinal lymphoma in adults.

The incidence of primary mediastinal lymphoma in adults was investigated in 184 patients with non-Hodgkin's lymphoma. This entity was defined as disease within the mediastinum in patients who presented with symptoms due to an enlarging mediastinal mass. Of 184 patients, 17 presented with primary mediastinal lymphoma. All had a diffuse histologic pattern. The most common pathologic type was poorly differentiated lymphocytic lymphoma, diffuse (PDL-D), (11 cases). In nine of these 11 cases the patients had tumors of convoluted lymphocytes. The presentation was rapid in onset, with heart failure, pericarditis, dyspnea and superior vena caval syndrome predominating. Eleven of the 17 were clinical stage I or II, but eight of these had widespread disease on pathologic staging or rapid dissemination soon after diagnosis. In conclusion (1) primary mediastinal lymphoma is always diffuse in histology. (2) The most frequent pathologic type is PDL-D, with convoluted morphology. (3) Compression of vital intra-thoracic structures is common. (4) Although seemingly localized at presentation, this entity usually implies disseminated disease.

Adult↗
PubMed1980

Orbital and adnexal lymphomas. A multiparameter approach.

The application of immunologic, cytochemical, and electron-microscopic technics to the study of lymphoid lesions of the orbit and adnexa was found to enhance the accuracy of diagnoses of malignant lymphoma in five challenging referral cases. Although careful specimen collection, ideal fixation, and processing constitute the cornerstone of the morphologic diagnosis of nodal and extranodal lymphomas, the immunologic characterization of these lymphoproliferative disorders is emphasized as an especially useful diagnostic parameter. The occurrence of false-negative diagnoses of pseudolymphoma of the orbital region may be partially explained by a failure to recognize the relatively frequent plasma-cytoid lymphocytic lymphoma, a distinctive entity that may mimic a reactive inflammatory process. All of the cases of malignant lymphoma reported represented stage I or stage II disease, suggesting that primary lymphoma of the orbital region may be a disease with a favorable prognosis.

Adult↗
PubMed1979

Collagen synthesis in normal BHK cells and temperature-sensitive chemically transformed BHK cells.

Collagen synthesis in normal BHK 21/cl 13 and chemically transformed temperature sensitive BHK 21/cl 13 cells (Me2N4) was assessed by examination of hydroxyproline formation and collagenase-susceptible protein. The Me2N4 cells lost their ability to synthesize collagen at both permissive and nonpermissive temperatures for transformation. These conclusions were confirmed by polyacrylamide-gel eletrophoresis and CM-cellulose chromatography. Prolyl hydroxylase activity was present in both normal and transformed cells even when no collagen could be demonstrated. The production of noncollagen protein, although decreased in the transformed cell, did not change as drastically as the collagen synthesis.

Animals↗
PubMed1979

A methodology for determining high risk components in urban environments.

A method of data collection and analysis is proposed for identifying environmental indicators significant to community health. The methods were applied to a study of child mortality in the city of Cali, Colombia. Pridit analysis (principal component analysis of ridits) is described. The methods have potential usefulness for monitoring and health care planning.

Colombia↗