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Biomedical subjects

S E Keller

Publications and source records attributed to S E Keller.

At least 19 recordsLinked to original sources
PubMed2001

Immune function in healthy inner-city children.

The importance of investigating immunity in healthy children has been underscored in the last few years by studies of the immune pathology of childhood illnesses, including human immunodeficiency virus. This study reports both ennumerative and functional immune measures in healthy inner city children. A total of 152 of 207 children studied were completely heathy at the time of venipuncture and were included in this study. Laboratory immune batteries were completed (or begun) the same day as venipuncture. Relationships between age, gender, ethnicity, and immunity were then analyzed. We found that gender predicted both the absolute number and the percentage of T cells and helper cells and the percentage of natural killer cells. Total leukocyte counts and percentages of lymphocytes and granulocytes were related to ethnicity, as was the response to mitogen stimulation (concanavalin A and pokeweed mitogen) and phagocytic ability. In conclusion, age, gender, and ethnicity factors were found to contribute to differences in various immune measures in children and require further investigation.

Child↗
PubMed2001

Hot water immersion to eliminate Escherichia coli O157:H7 on the surface of whole apples: thermal effects and efficacy.

The effect of hot water immersion on both the reduction of Escherichia coli O157:H7 on the apple surface and internal temperatures of the apple was assessed in this study. Microbial reductions were measured experimentally, whereas internal temperatures were calculated through a mathematical analysis of experimental heat transfer data obtained from the apples. A method was developed to provide a purely surface-based inoculation of E. coli O157:H7. Rinsing produced no reduction, and treatments at 80 and 95 degrees C produced reductions of more than 5 logs in 15 s or less. The heat transfer analysis based on experimental data was used to calculate surface heat transfer coefficients and predict temperatures throughout the apple. The analysis indicated a low heat transfer rate. Although it reduces thermal degradation, a low heat transfer rate precludes thermal-based reduction of any internalized microorganisms.

Colony Count, Microbial↗
PubMed2000

Influence of neurological level on immune function following spinal cord injury: a review.

Due to the high incidence of lifelong infections in persons with spinal cord injury (SCI), the authors examined level of injury-related immune characteristics in a cohort of subjects with chronic SCI. Since the sympathetic nervous system and the endocrine system are known to be modulators of immune function, one possible explanation for heightened incidence of infections includes dysregulation of sympathetic outflow tracts in individuals with tetraplegia or high paraplegia. Natural killer cell cytotoxicity (NKCC) and bactericidal function of circulating neutrophils were assayed in a group of 10 individuals with chronic complete cervical SCI, a group of 8 individuals with paraplegia with injuries below the main sympathetic outflow (T-10 and below) and a group of 18 age- and sex-matched controls. In addition, a psychiatric assessment of depression was performed as well as assays of pituitary and adrenal functions. Analyses revealed no significant differences in immune function between all subjects with SCI combined and their matched controls. Further analyses stratifying based on presence or absence of sympathetic dysregulation revealed significantly impaired phagocytic ability and a trend toward reduced NKCC in the group with tetraplegia compared with their controls. Hormonal assays showed that dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulfate (DS) were higher in individuals with tetraplegia than controls, but no such differences were observed in individuals with paraplegia compared with their controls. The results of this study suggest that individuals sustaining complete cervical SCI experience alterations in immune function, while those with lesions at or below T-10 do not. These findings of level of injury related immune alteration could not be explained by mood differences. This paper is a review of previously published work and the authors' current thinking regarding increased acquisition of infections in this population.

Adult↗
PubMed1999

Depression and immunity: clinical factors and therapeutic course.

While many reports describe associations between depressive disorders and altered immunity, findings have not been fully consistent. Diagnostic subtype, demographic factors such as age and gender, medical characteristics, and the immune measures selected for assessment may have contributed to the heterogeneous findings. In a study of 21 medically healthy young adults with major depression, we found, consistent with previous reports, evidence of increased lymphocyte activation to mitogen challenge and decreased natural killer (NK) cell numbers and function during acute depression. Fifteen subjects were followed longitudinally. T, CD4+, CD29+, and CD45RA+ lymphocytes and T-cell mitogen responses decreased significantly (P<0.05) during 6 weeks of pharmacotherapy and concurrent clinical improvement. There was no change in NK activity or CD56+ cells. The longitudinal effects appeared unrelated to tricyclic antidepressant levels. Changes in the immune system with short-term clinical improvement in depressed patients are not uniform providing further evidence that several mechanisms are involved in the altered immunity associated with clinical depression.

Adolescent↗
PubMed1999

Self-reported systemic, immune-mediated disorders in patients with and without proplast-teflon implants of the temporomandibular joint.

PURPOSE: This study investigates the self-reported immune-related health status of patients exposed to Proplast-Teflon (P/T) temporomandibular joint (TMJ) implants, comparing their health status with a group of patients who were not exposed to any alloplastic TMJ implants. It also compares those whose implants were removed with those in whom they were retained. PATIENTS AND METHODS: Patients seen in a single oral and maxillofacial surgical practice completed a detailed self-report questionnaire about physical symptoms and disorders. Sixty-four had received P/T implants, and 22 were unexposed to any TMJ alloplastic implant. Of the P/T-exposed group, 44 had removed and 20 had retained implants. RESULTS: In general, P/T-exposed patients did not differ from unexposed patients in rates of reported immune-mediated and somatization-related conditions, allergies, or symptoms of environmental sensitivity. However, patients with removed P/T implants reported significantly more problems in all categories of conditions than those with retained P/T implants. This difference was no longer statistically significant after controlling for pain severity and sex. CONCLUSIONS: Although P/T-exposed patients do not report more systemic health conditions than similar patients who were unexposed to alloplastic jaw implants, those with removed implants report more conditions and are more likely to be seen in clinical practice. This may lead to a bias in the general perception regarding the systemic health status of P/T-exposed patients. In addition, effects may be secondary to high levels of pain and dysfunction among patients with removed implants, rather than implant exposure itself. Future prospective research is needed to identify factors associated with implant failure.

Adult↗
PubMed1999

Immune changes in alcohol-dependent patients without medical disorders.

INTRODUCTION: We examined a battery of in vitro immune measures in inner city alcohol-dependent (as determined by the Structured Clinical Interview for DSM-III-R (SCID) persons who were without liver or other medical disorders and free of other substance abuse. These subjects were seeking treatment at an ambulatory alcohol treatment center. METHODS: Alcohol-dependent subjects (n = 44) were compared with healthy, nonabusing community subjects (n = 34). Subjects, both male and female, had a mean age of 41 years and were primarily African American. Many were homeless. An extended battery of enumerative and functional immune measures was obtained, as well as information about alcohol consumption. RESULTS: CONTROLLING for age and gender, ANCOVA revealed no differences (p > 0.1) between alcohol-dependent and control subjects in leukocyte and lymphocyte subsets or in circulating CD56+ (natural killer) cells. There were also no significant differences in responses to the mitogens phytohemagglutinin, concanavalin A, or pokeweed mitogen ( > 0.1) or in natural killer cell activity (p > 0.1). There was, however, altered granulocyte function in the alcohol-dependent sample, with decreased phagocytic activity in the alcohol-dependent males (p < 0.04) and gender and age dependent differences in the number of circulating granulocytes (p < 0.01). Granulocyte killing of Staphylococcus aureus, however, did not differ between the groups. CONCLUSIONS: The findings suggest that although males with chronic alcohol dependence have compromised phagocytic function, chronic alcohol-dependent subjects who are free of medical disorders do not have substantial abnormalities in many immune system functions.

Adult↗
PubMed1998

Immune function in healthy adolescents.

In the present study, we examine immunological functioning in normal healthy African-American and Latino/Latina adolescents recruited from an inner-city high school and an inner-city clinic. A battery of tests was performed with enumerative and functional measures which encompassed both innate and adaptive immunity. We found immune differences related to age, gender, and race on both the enumerative and the functional immune measures. This data expands the available body of information concerning normal immunity in healthy adolescents.

Adolescent↗
PubMed1998

Systemic health consequences of alloplastic implants of the TMJ: a pilot study.

The aim of this study was to examine the relation between alloplastic temporomandibular joint (TMJ) implants and immune-associated systemic health problems. The authors compared 14 patients who received alloplastic TMJ implants with 31 TMJ patients who had never received surgery on the self-reported occurrence of symptoms and systemic disorders that are associated with problems of immunomodulation. Those with alloplastic jaw implants reported similar or lower rates of surveyed physical disorders than nonsurgical TMJ participants. When the rates were summed across symptom categories and physical disorders, implant participants had significantly fewer symptoms and disorders than nonsurgical participants (P < 0.01). This first report on systemic health problems in alloplastic TMJ implant patients found no evidence of elevated rates of systemic disorders that are associated with problems of immunomodulation.

Adult↗
PubMed1997

Factors affecting the growth of Fusarium proliferatum and the production of fumonisin B1: oxygen and pH.

Fumonisins are mycotoxins produced primarily by Fusarium moniliforme and Fusarium proliferatum in corn. In liquid culture, production of fumonisin B1 (FB1), the most common moiety of the family of fumonisins, can be obtained using a defined medium that is nitrogen-limited. Under nitrogen-limited conditions both growth and the production of FB1 were greatly influenced by pH and aeration. At pH above 5.0, F. proliferatum grew normally but produced little FB1 (< 100 micrograms m-1). At pH below 5.0, there was less growth but substantially more FB1. Below a pH of 2.5, both growth and metabolism were slower with very little FB1 produced. When the optimal pH range of between 3.0 and 4.0 under well-aerated conditions was used, both growth and FB1 production were high. However, under oxygen-limited conditions, less growth occurred, glucose consumption was increased, and no FB1 was produced.

Bioreactors↗
PubMed1997

Phagocytosis and killing of Staphylococcus aureus: effects of stress and depression in children.

While a large body of literature depicting relationships between depression or stress and immunity exists, few such studies have dealt with children, and none investigated myeloid cell-derived immunity. We investigated both phagocytosis and bactericidal activity against Staphylococcus aureus in children with major depressive disorder (MDD). We found that both MDD and stress influence the bactericidal but not the phagocytic activity of polymorphonuclear leukocytes. The data support the existence of psychobiologic effects in children and suggest possible mechanisms by which depression and stress may affect health.

Blood Bactericidal Activity↗
PubMed1996

Recent benzodiazepine use in depressed patients: a confound of psychoimmunologic studies?

UNLABELLED: Several studies have indicated that benzodiazepines influence immunity in both animals and humans. As these medications are commonly utilized by and for psychiatric patients, investigation of psycho-immunologic relationships in human psychiatric disorders may be confounded by use of these medications. METHOD: We undertook an investigation for possible effects of recent benzodiazepine use on depression-immune relationships by comparing 43 patients with current major depressive disorder (MDD) who used benzodiazepines in the week prior to study to 27 patients with current MDD but no use of benzodiazepines in the past month. Both functional and ennumerative measures were investigated. RESULTS: We found no differences in absolute numbers of lymphocytes or the lymphocyte and NK functional measures. We did find differences between these two groups in the percentage of lymphocytes and of NK cells. Upon further analysis, controlling for symptom severity, these differences were shown to not be independently predicted by benzodiazepine use. CONCLUSION: Immune measures in subjects with current MDD and recent benzodiazepine use did not differ from those without such recent use. Therefore, such recent use is unlikely to confound PNI results.

Adult↗
PubMed1996

Liquid culture methods for the production of fumonisin.

Currently, fumonisin B1 is obtained primarily by using solid culture methods. Although fumonisin B1 concentrations obtained in solid culture are typically quite high, subsequent extraction and purification present problems. In addition, current methods utilize complex media which makes analysis of biosynthetic pathways and control mechanisms difficult. Liquid culture methods of production could eliminate many problems associated with production in solid culture. However, in the past, concentrations obtained in liquid culture have been relatively low. In this work, factors affecting the production of fumonisin B1 from a shake flask scale of 100 ml to a fermenter scale of 100 liters were examined. Best results were obtained by using a fed batch method that is nitrogen limited, with pH control. With this method, concentrations in excess of 1000 ppm can be obtained.

Culture Media↗
PubMed1996

Human immunodeficiency virus-type 1 infection in an inner-city alcohol treatment program.

The human immunodeficiency virus (HIV) infection rate was examined in a selected cohort of healthy clients of an inner-city alcohol treatment center from 1990 through 1993. These subjects were also participating in a research protocol (n = 258) designed to assess immunity and HIV risk behaviors in inner city alcohol-dependent persons. Healthy alcohol-abusing heterosexual clients (165) had HIV testing conducted in an inner-city ambulatory alcohol treatment center between September 1990 and December 1993. Respondents were 93.9% African-American and 3.6% Hispanic; 72.1% were male. Anonymous HIV-1 antibody testing was conducted retrospectively for an additional 80 subjects who participated in the research protocol during the same interval, but for whom HIV-1 antibody testing was not conducted clinically at the time. HIV infection rate among the clinic-tested subjects (n = 165) was 4.4% for individuals who were exclusively alcohol-dependent, 1.4% for non-injecting drug use (IDU) mixed substance abusers, and 46.8% for clients with a history of IDU. Rates did not differ among cohorts tested in different years. Among non-injecting drug users tested in the clinic, all infected respondents (n = 3) were women (p = 0.03). Among those tested anonymously (n = 80), however, infection rate for exclusively alcohol-dependent persons was 16.7%, non-IDU mixed abusers 11.1%, and injecting drug users 48.3%, with seropositive males as well as females in each group. HIV infection rates for the pooled samples (n = 245) were 8.7% for exclusively alcohol-dependent persons, 5.1% for mixed abusers, and 54.5% for injecting drug users. Among non-injecting drug users, exclusively alcohol-dependent women had a significantly higher (p < 0.01) infection rate (20.0%) than the remaining females and males. Infection rates among exclusively alcohol-dependent males, male and female polysubstance non-IDU abusers, and injecting drug users were comparable with that seen in an earlier screening in the same clinic in 1989, with apparently little diffusion of infection from the IDU population to other substance abusers. An exception seemed to be exclusively alcohol-dependent females, who show substantially elevated rates. Age, housing, and other social differences may help segregated substance-abusing populations in the relatively small Newark metropolitan area, although not protecting exclusively alcohol-dependent females.

Adult↗
PubMed1996

Immunity in young adults with major depressive disorder.

OBJECTIVE: The authors previously found evidence for an age-related association between major depression and altered immunity. The present study was designed to assess a range of immune measures in young adults with major depression. METHOD: A homogeneous group of 21 unmedicated, ambulatory young adults with unipolar major depressive episode, as determined with the Structured Clinical Interview for DSM-III-R, were assessed in comparison with 21 matched nondepressed subjects. An extended battery of quantitative and functional immune measures was obtained on the same day from depressed and nondepressed subjects. RESULTS: Young adult subjects with major depression had more circulating leukocytes and granulocytes, fewer CD56+ (natural killer [NK]) cells, and, when the number of circulating NK cells was controlled, less NK cell activity. Mitogen responses, consistent with the authors' previous report, showed little difference between the young adults with and without major depression except for a possibly greater response at the highest dose of phytohemagglutinin. CONCLUSIONS: Major depression in young adults is associated with alterations in aspects of the immune system primarily involving NK cells. Some but not all these immune changes differ from those found in older depressed adults.

Adult↗
PubMed1995

Efficacy and tolerability of losartan potassium and atenolol in patients with mild to moderate essential hypertension.

The objective of this study was to compare the antihypertensive efficacy and tolerability of losartan potassium (losartan) and atenolol in patients with mild-to-moderate essential hypertension. This was a multinational, prospective, randomized, 12-week double-blind parallel study with a follow-up of 4 to 10 days posttreatment to assess any adverse effects of abrupt therapy withdrawal. Two hundred two patients were randomized (2:1) to treatment with losartan or atenolol, 50 mg once daily. Patients were titrated after 6 weeks to 100 mg once daily if their blood pressure was uncontrolled (sitting diastolic blood pressure > or = 90 mm Hg). Trough sitting diastolic blood pressure reductions at weeks 6 and 12 were similar in both the losartan (-9.2 mm Hg and -8.3 mm Hg) and atenolol (-10.8 mm Hg and -10.1 mm Hg) groups and a similar percentage of patients responded to each drug. Both agents were generally well tolerated, although eight patients (two patients taking losartan, and six taking atenolol) were withdrawn because of clinical adverse events (P < or = .05). Reduction in pulse rate from baseline averaged 10 beats/min in the atenolol group with no pulse rate reduction observed in the losartan group (P < .01). No evidence of rebound hypertension was observed in either group. In conclusion, losartan was as efficacious as atenolol in blood pressure reduction, and was at least as well tolerated.

Adult↗
PubMed1994

Electrical stimulation of the dorsal midbrain periaqueductal gray suppresses peripheral blood natural killer cell activity.

This study examined the effects of dorsal midbrain periaqueductal gray (PAG) stimulation on both splenic and peripheral blood natural killer (NK) cell function as well as the proliferative response of lymphocytes to phytohemagglutinin mitogen. Male Sprague-Dawley rats were implanted with bipolar electrodes in the dorsal PAG. Following recovery, bipolar electrical stimulation eliciting a flight response was delivered at the rate of one/min for 30 min to freely moving rats. While dorsal PAG stimulation did not alter mitogen response or splenic NK activity, stimulation of this region of the PAG produced a marked decrease in peripheral blood NK response. In order to begin to explore a possible mechanism regulating suppression of peripheral blood NK activity, naltrexone (10 mg/kg) was administered prior to dorsal PAG stimulation. The results of this experiment replicated the findings that demonstrated suppression of peripheral blood NK following dorsal PAG stimulation. Naltrexone did not effect PAG induced suppression of peripheral blood NK. These findings point to the importance of the dorsal aspect of the PAG in the regulation of peripheral blood NK activity and further suggest that this phenomenon may not be opioid mediated.

Animals↗
PubMed1993

Analysis of partial variance (APV) as a statistical approach to control day to day variation in immune assays.

The considerable day to day variability in some immunologic assays can obscure relationships among measures of interest and thereby complicate interpretation of findings when effect sizes are modest. Analysis of partial variance (APV) is a technique that utilizes data obtained from controls run in the laboratory on the day of each assay to control for day to day variance statistically. The application of this technique to permit detection of otherwise obscured effects for both larger and smaller samples is exemplified utilizing data from two studies in which subjects were assessed on multiple different dates. These included a study of the association of depression with in vitro immune measures in 296 adolescents and a longitudinal study of 20 spouses of patients admitted to a cardiac intensive care unit studied together with 20 matched controls. APV was most useful in analyses of mitogen-induced lymphocyte proliferation assays, which had considerable day to day variability. In general, multivariate studies with functional immune measures may benefit most from application of this technique.

Adolescent↗