Biomedical subjects

L A Evans

Publications and source records attributed to L A Evans.

At least 37 records · Page 2Linked to original sources

PubMed1988

Simultaneous isolation of HIV-1 and HIV-2 from an AIDS patient.

Two distinct human immunodeficiency viruses, HIV-1SF480 and HIV-2UC2 were isolated simultaneously from the blood of an Ivory Coast patient with AIDS. The HIV subtypes were segregated by their differential ability to infect established human cell lines and by the cell surface expression of type-specific viral antigens. The viruses could be distinguished by both immunoblot and Southern blot analyses. The results indicate that an individual can be infected by both HIV subtypes.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Characterization of a noncytopathic HIV-2 strain with unusual effects on CD4 expression.

A new isolate of the human immunodeficiency virus type 2, designated HIV-2UC1, was recovered from an Ivory Coast patient with normal lymphocyte numbers who died with neurologic symptoms. Like some HIV-1 isolates, HIV-2UC1 grows rapidly to high titers in human peripheral blood lymphocytes and macrophages and has a differential ability to productively infect established human cell lines of lymphocytic and monocytic origin. Moreover, infection with this isolate also appears to involve the CD4 antigen. However, unlike other HIV isolates, HIV-2UC1 does not cause cytopathic effects in susceptible T cells nor does it lead to loss of CD4 antigen expression on the cell surface. These results indicate that HIV-2 may be found in individuals with neurologic symptoms and that the biological characteristics of this heterogeneous subgroup can differ from those typical of HIV-1.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Human monoclonal antibody directed against gag gene products of the human immunodeficiency virus.

Tonsillar B lymphocytes from an asymptomatic individual infected with HIV were transformed with EBV. A cloned lymphoblastoid cell line was obtained that secreted human mAb (IgG4 subtype) against the known gag gene products of 55,000 and 25,000 Da and a protein of 40,000 Da. The latter p40 protein appears to be a HIV gag-related gene product that is also recognized immunologically by individuals infected by HIV. Although the mAb detects infection of cells by different HIV isolates, it does not neutralize HIV or show activity in an antibody-dependent cytotoxicity assay.

Antibodies, Monoclonal↗

PubMed1988

Identification of human immunodeficiency virus subtypes with distinct patterns of sensitivity to serum neutralization.

The human immunodeficiency virus (HIV) type 1 displays a high degree of genetic variation, especially in the glycoprotein (gp120) domain of the envelope gene. To determine whether this genomic heterogeneity leads to the expression of independent HIV subtypes, 12 sera from HIV type 1 antibody-positive individuals were tested for their ability to neutralize 20 HIV isolates of various origins. Four distinct HIV subtypes with different sensitivity to serum neutralization were identified. These results suggest that a finite number of HIV subtypes exist and that the combined use of selected HIV isolates representing several subtypes may be necessary for the development of an effective vaccine.

HIV↗

PubMed1988

HIV heterogeneity and viral pathogenesis.

HIV research in the past year has elucidated many questions relevant to strategies for treatment and control. For instance, there is a greater understanding of the diversity of HIV isolates as well as the wide range of potential cells sensitive to infection. The search for a safe, effective vaccine now calls for more caution in the light of the discovery of neutralization-resistant variants and antibody-mediated enhancement of infection. Efforts to control HIV must take into account the various mechanisms of virus entry into host cells, and the processes involved in cytopathic effects. Moreover, the role of cells of the mononuclear phagocyte system as reservoirs for HIV particles should be recognized. Together with new information about cytokine induction of HIV, the concept of latent infection of monocytes and macrophages has profound implications for virus persistence and dissemination, especially in the seronegative individual. While many factors about HIV have been uncovered in the past year, several questions remain unanswered and new ones have arisen. For instance, in how many ways does the virus kill in host cell? What causes latency and why does it occur in some but not all hosts? How can virus-filled macrophage vesicles be reached by therapeutic agents or prevented from releasing HIV? What surveillance mechanisms allow some productively infected hosts (cells as well as individuals) to survive beyond expectation? These and other questions should provoke future research on this presently complex and challenging pathogen.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Human immunodeficiency virus recovery from bronchoalveolar lavage fluid in patients with AIDS.

We cultured bronchoalveolar lavage fluid for the human immunodeficiency virus (HIV) from 23 consecutive patients with acquired immunodeficiency syndrome (AIDS) and pulmonary symptoms. We also included a nonconsecutive AIDS patient with recent worsening of respiratory symptoms who had had lymphocytic interstitial pneumonitis (LIP) diagnosed six months earlier. Infectious HIV was present in the cellular fraction from two of the 23 consecutive patients and in the patient with LIP. No virus was isolated from the cell-free portion of the centrifuged fluids. The patients from whom HIV was cultured were not distinguishable from other patients by clinical, radiographic, or laboratory data, and their subsequent course did not appear to differ. One patient with a positive HIV culture had organizing pneumonia without evidence of LIP at autopsy three weeks after lavage. This study demonstrates that HIV can be cultured from cells obtained by bronchoalveolar lavage and suggests that its presence is not associated with a single specific pulmonary histologic pattern.

Acquired Immunodeficiency Syndrome↗

PubMed1987

Differential ability of human immunodeficiency virus isolates to productively infect human cells.

Isolates of HIV showed distinct differences in the ability to replicate in continuous human hematopoietic cell lines. Moreover, although all PMC cultures obtained from healthy individuals could be infected with HIV, considerable variation in the amount of virus released from different PMC cultures was observed. These biological properties of HIV could not be correlated with clinical state, binding properties of the virus isolates to target cells, or differences in target cell CD4 antigen expression. Some isolates of HIV that could not directly infect the HUT-78 cell line showed productive infection when PMC infected with these viruses were added to this human T cell line. These observations emphasize the importance of cell to cell contact in the spread of virus. The results demonstrate for the first time the differences in the host range specificity of HIV isolates in several individual PMC cultures, and indicate that the optimal isolation of HIV is achieved with normal human PMC rather than established human cell lines.

Acquired Immunodeficiency Syndrome↗

PubMed1987

Intracellular pH in the rat mandibular salivary gland: the role of Na-H and Cl-HCO3 antiports in secretion.

Intracellular pH (pHi) in the perfused rat mandibular gland was determined from the distribution of DMO (5,5-dimethyl-2,4-oxazolidinedione). In unstimulated glands, pHi averaged 7.12 +/- 0.02. Stimulation with a "standard" (submaximal) concentration (0.3 mumol/l) of acetylcholine (ACh) caused a fall in pHi to 6.81 +/- 0.06 over 60 min, but a maximal concentration (1.0 mumol/l) caused an initial rise in pHi to 7.60 +/- 0.02, followed by a fall to 7.45 +/- 0.02 over 60 min. After replacement of perfusate Cl with gluconate, the standard ACh concentration caused a rise in pHi to 7.50 +/- 0.02 followed by a fall to 7.27 +/- 0.04 after 60 min, concomitant with a 76% fall in secretory rate and a rise in salivary HCO3 concentration from 14 +/- 0.9 to 67 +/- 1.5 mmol/l. Furosemide (1 mmol/l) had a similar effect to gluconate replacement except that secretory rate fell only by 60%. Bumetanide (1 mmol/l), which inhibited secretion by 67%, did not cause pHi to rise following ACh stimulation but prevented the fall seen with ACh alone. Acetazolamide and methazolamide (1 mmol/l) had no effect on the salivary secretory response to ACh but they caused pHi to rise, respectively, to 7.20 +/- 0.03 and 7.43 +/- 0.02. Bumetanide and methazolamide together caused pHi to rise to 7.58 +/- 0.02 and reduced the secretory response to ACh by 91%. The disulfonic stilbene, SITS, caused pHi to rise to 7.26 +/- 0.03. Ouabain and amiloride both caused resting pHi to fall closer to equilibrium and largely abolished the gland's responsiveness to ACh.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1987

Effects of ion transport inhibition on rat mandibular gland secretion.

The effects of substituting gluconate for extracellular Cl, and of treatment with various ion transport blockers, on cytosol pH (pHi) and secretion by the acetylcholine stimulated rat mandibular gland were studied in vitro. Gluconate replacement increased pHi from 7.12 +/- 0.02 to 7.27 +/- 0.04, caused secretory rate to fall by 75%, and increased salivary HCO3 from 14 +/- 0.9 mmol/L to 67 +/- 1.5 mmol/L. Furosemide (1 mmol/L), which blocks Na-K-2Cl symports and Cl-HCO3 antiports, had effects similar to those of gluconate replacement, except that secretion was reduced only by 59%. Bumetanide (1 mmol/L), which blocks only Na-K-2Cl symports, caused a 67% reduction in secretion rate, but it had little effect on pHi and caused only a small rise in salivary HCO3 concentration. SITS (1 mmol/L), which blocks Cl-HCO3 antiports, increased pHi to 7.26 +/- 0.03 and induced a small rise in the secretory rate. Methazolamide and acetazolamide (1 mmol/L), both of which inhibit carbonic anhydrase and may also block anion channels, increased pHi to 7.43 +/- 0.02 and 7.20 +/- 0.03, respectively, but had no effect on secretory rate, and reduced salivary HCO3 slightly. Ba (3 mmol/L), tetraethylammonium (10 mmol/L), and decamethonium (5 mmol/L) all caused marked but reversible reductions in secretory rate, consistent with the known actions of these agents on K channels. Ba, however, also appeared to act as a Ca antagonist, an action that it seemed to share with Mn ions (5 mmol/L).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1986

Isolation of AIDS-associated retrovirus from genital secretions of women with antibodies to the virus.

The AIDS-associated retrovirus (ARV) was isolated from vaginal and/or cervical secretions from 4 out of 8 women whose sera contained antibodies to the virus. The quantity of virus recovered initially was so low that identification of ARV was accomplished only after passage of the isolates to cultured mitogen-stimulated normal human peripheral blood mononuclear cells. The results indicate that the vaginal canal under certain conditions could be a source of transmission of ARV.

Acquired Immunodeficiency Syndrome↗

PubMed1986

Patient requests: correlates and therapeutic implications for Hispanic, black, and Caucasian patients.

A patient's reason for coming to a psychiatric outpatient clinic (his/her request for service) should be the focal point as a therapist develops an appropriate therapeutic plan for that patient. Data have been collected on 173 Hispanic, Black and Caucasian patients with regard to their reasons for coming to the clinic and selected demographic and process/outcome variables. A factor analysis of the patient request data generated three conceptual factors, which account for 13 reasons for coming to the clinic. The relationship of these factors with selected demographic and therapy outcome variables was tested statistically, and implications for therapy with low income and minority patients are discussed.

Adult↗

PubMed1986

Intraepithelial current flow in rat pancreatic secretory epithelia.

To assess the importance for transepithelial salt secretion of current flow across the baso-lateral membrane, we studied the effects of ouabain (1 mmol/l), Ba (3 mmol/l) and tetraethylammonium (TEA: 10 mmol/l) on secretion by the acinar (caerulein stimulated) and ductal (secretin stimulated) epithelia of the perfused rat pancreas. Within 10 min, ouabain caused a 79% inhibition of acinar secretion which was resolvable into two exponentials with half-times, respectively, of 0.24 min +/- 0.19 (S.D.) and 6.40 +/- 0.46 min. In contrast, it caused only a monoexponential inhibition of ductal secretion (61% in 10 min) with a half-time of 5.08 +/- 0.26 min. Ba caused a monoexponential inhibition of acinar secretion (70% in 10 min) with a half-time of 1.82 +/- 0.27 min, but it had no inhibitory effect on ductal secretion. The action of TEA was similar to that of Ba: it caused monoexponential inhibition of acinar secretion (26% in 10 min) with a half-time of 1.82 +/- 0.03 min, and it too had no effect on ductal secretion. For comparison, we also studied the effect of these drugs on the more rapidly secreting rat mandibular gland (stimulated with acetylcholine). All three drugs were strongly inhibitory: within 10 min, ouabain caused a 95%, Ba an 89% and TEA an 83% inhibition. The decay curves appeared to be monoexponential with half-times, respectively, of 1.49 +/- 0.12, 0.51 +/- 0.3 and 0.56 +/- 0.02 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1985

Analysis of the HSV-2 early AG-4 antigen.

Genital herpes simplex virus type 2 (HSV-2) infections can be distinguished from present or past HSV-1 infections by an AG-4 antigen complement fixation assay. The assay which utilizes a 4 hour HSV-2 infected cell extract prepared at a multiplicity of infection (MOI) of 1.0 PFU/cell, appears to consist of several viral proteins. Studies using monoclonal antibodies, polyclonal rabbit hyperimmune serum, HSV-1 X HSV-2 intertypic recombinant viruses and polyacrylamide gel electrophoresis suggest that ICP 8 may be one of the major antigens involved in the complement fixing reaction. It is probable that the success of the assay is not due to a true type specificity but rather a threshold phenomenon in which HSV-2 extracts contain more early viral antigens (including ICP 8) and sera from HSV-2 patients contain more complement fixing antibody to these antigens.

Animals↗

PubMed1984

Orienting psychotherapists to better serve low income and minority patients.

As a part of a larger NIMH study, 29 psychotherapists who were beginning training at a large urban psychiatric outpatient clinic participated in a special orientation program. The orientation program had the following objectives: First, to increase the therapists' knowledge about low income and minority patients; second, to increase the therapists' sensitivity to minority patients' requests and problems; and, third, to increase the effectiveness of the therapeutic encounter. The majority of therapists acted as their own controls; they saw patients before and then after participating in the orientation program. Data indicated that therapists improved significantly in knowledge, sensitivity, and effectiveness as a result of the special therapist orientation program.

Adult↗

PubMed1984

Self-reported psychiatric symptoms among black, Hispanic, and white outpatients.

Examined ethnic differences among black, Hispanic, and white applicants for outpatient psychotherapy, using symptoms self-reported on the Symptom Checklist 90-Revised (SCL 90-R). The relationship between self-reported severity of symptoms and therapist-reported severity of psychiatric diagnoses also was examined in order to assess the utility of SCL 90-R as a predictor of diagnostic severity for these ethnic groups. One hundred sixty-five patients completed the SCL 90-R. The patients were predominantly in the low-income social classes. A significant ethnic effect was found on several symptom dimensions, with black patients less likely to report symptoms than Hispanic or white patients. Hispanic patients were found to report the highest symptom levels on 8 of 11 measures. While, overall, therapist diagnostic severity was related significantly to self-reported symptomatology, the relationship was strongest for white patients, significant but less strong for Hispanic patients, and not significant for black patients.

Adult↗

PubMed1984

Orienting therapists about patients' needs to increase patient satisfaction.

Twenty-nine psychotherapists received orientation about patients' cultural background, expectations, and therapeutic needs. They treated 98 patients before orientation and 73 afterward, and a follow-up interview was conducted 4-6 weeks after completion of therapy. The patients seen after therapist orientation were more satisfied with the services, felt better able to handle problems, were more likely to seek therapy for future problems, and felt more strongly that their needs for clinic services had been met than the patients seen by therapists before orientation. Analyses of therapist experience, patients' ethnicity, and patients' orientation to psychotherapy showed no significant interactions with patient satisfaction.

Adult↗

PubMed1983

Preparing low-income hispanic, black, and white patients for psychotherapy: evaluation of a new orientation program.

Examined the effectiveness of a new orientation program designed to prepare low-income white and ethnic minority outpatients for psychotherapy. Sixty-two Hispanic, 51 black, and 60 white psychiatric outpatients in a large public psychiatric clinic participated prior to their first psychotherapy interview. Patients were presented with one of two experimental conditions; the oriented patients saw an audiovisual program that instructed them about psychotherapy, and the control patients saw a program that was neutral with regard to psychotherapy. The patients' knowledge and attitudes toward psychotherapy were assessed with two questionnaires. Results indicated that patients who were oriented were more knowledgeable about psychotherapy and more positive in their attitudes toward psychotherapy than were patients who had not been oriented. The role and utility of brief orientation programs for low-income and ethnic minority outpatients in public mental health facilities are discussed.

Adult↗

PubMed1983

Compliance with chemotherapy: theoretical basis and intervention design.

An experimental chemotherapy compliance enhancement program has been developed based on theory and findings from social psychology and learning theory. The essential ingredients are individualized instruction, behavior shaping and enhancement of social and environmental supports. The differential effects of these interventions upon compliance, as measured both by patient self-reports and by objective pharmacokinetic assays, are being tested.

Antineoplastic Agents↗