Biomedical subjects

J G Johnson

Publications and source records attributed to J G Johnson.

At least 37 records · Page 2Linked to original sources

PubMed1999

Induction of primary human CD8+ T lymphocyte responses in vitro using dendritic cells.

The ability of two different human professional APCs, specifically macrophages (Mphi) and dendritic cells (DC), to stimulate primary responses in human CD8+ T lymphocytes was examined using both allogeneic and Ag-pulsed autologous APCs. CTL responses in CD8+ T lymphocytes isolated from HIV-uninfected donors were evaluated against six different HIV epitopes that are restricted by four different HLA alleles using autologous human PBMC-derived Mphi and DCs for primary stimulation. In a side-by-side experiment, immature DCs, but not Mphi, were able to prime a CTL response against the B14-restricted p24gag 298-306 epitope; mature DCs were also able to prime a response against this epitope. In addition, DCs were capable of priming CD8+ CTL responses against the B8-restricted p24gag 259-267 epitope. In contrast, Mphi were unable to prime strong CTL responses against other epitopes. Since the Ag-specific cytotoxic responses required subsequent rounds of restimulation before they could be detected, the ability of the allogeneic Mphi and DCs to directly prime CD8+ T lymphocyte responses without subsequent restimulation was examined. Similar to the aforementioned peptide-specific results, DCs were more efficient than Mphi in priming both allogeneic proliferative and cytotoxic responses in human CD8+ T lymphocytes. Collectively, these results promote an enhanced status for DCs in the primary stimulation of human CD8+ T lymphocytes.

CD8-Positive T-Lymphocytes↗

PubMed1999

Childhood maltreatment increases risk for personality disorders during early adulthood.

BACKGROUND: Data from a community-based longitudinal study were used to investigate whether childhood abuse and neglect increases risk for personality disorders (PDs) during early adulthood. METHODS: Psychosocial and psychiatric interviews were administered to a representative community sample of 639 youths and their mothers from 2 counties in the state of New York in 1975, 1983, 1985 to 1986, and 1991 to 1993. Evidence of childhood physical abuse, sexual abuse, and neglect was obtained from New York State records and from offspring self-reports in 1991 to 1993 when they were young adults. Offspring PDs were assessed in 1991 to 1993. RESULTS: Persons with documented childhood abuse or neglect were more than 4 times as likely as those who were not abused or neglected to be diagnosed with PDs during early adulthood after age, parental education, and parental psychiatric disorders were controlled statistically. Childhood physical abuse, sexual abuse, and neglect were each associated with elevated PD symptom levels during early adulthood after other types of childhood maltreatment were controlled statistically. Of the 12 categories of DSM-IV PD symptoms, 10 were associated with childhood abuse or neglect. Different types of childhood maltreatment were associated with symptoms of specific PDs during early adulthood. CONCLUSIONS: Persons in the community who have experienced childhood abuse or neglect are considerably more likely than those who were not abused or neglected to have PDs and elevated PD symptom levels during early adulthood. Childhood abuse and neglect may contribute to the onset of some PDs.

Adolescent↗

PubMed1999

Personality disorders in adolescence and risk of major mental disorders and suicidality during adulthood.

BACKGROUND: A community-based longitudinal study was conducted to investigate whether personality disorders (PDs) during adolescence increase the risk for Axis I psychiatric disorders and suicidality during early adulthood. METHOD: Psychosocial and psychiatric interviews were administered to a representative community sample of 717 youths and their mothers from 2 counties in the state of New York in 1975, 1983, 1985-1986, and 1991-1993. Anxiety, disruptive, eating, mood, personality, and substance use disorders and suicidal ideation and behavior were assessed in 1983 and 1985-1986, when the participants were adolescents, and in 1991-1993, when they were young adults. RESULTS: Adolescents with PDs were more than twice as likely as those without PDs to have anxiety, disruptive, mood, and substance use disorders during early adulthood. These associations remained statistically significant after co-occurring Axis I disorders during adolescence were controlled statistically. Cluster A, B, and C PDs and DSM-IV Appendix B PDs during adolescence were all associated with elevated risk for Axis I disorders during early adulthood after co-occurring Axis I and Axis II disorders during adolescence were controlled statistically. Cluster C PDs during adolescence were associated with elevated risk for suicidal ideation or behavior during early adulthood after co-occurring psychiatric disorders and suicidality during adolescence were controlled statistically. CONCLUSIONS: Adolescents in the community with personality disorders are at elevated risk for major mental disorders and suicidal ideation or behavior during early adulthood. This increase in risk is not accounted for by co-occurring Axis I disorders or suicidality during adolescence.

Adolescent↗

PubMed1999

A longitudinal investigation of social causation and social selection processes involved in the association between socioeconomic status and psychiatric disorders.

Social causation theory and social selection theory have been put forth to explain the finding that low socioeconomic status (SES) is associated with risk for psychiatric disorders. The predictions of both theories were investigated using data from a community-based longitudinal study. Psychosocial interviews were administered to 736 families from 2 counties in New York State in 1975, 1983, 1985-1986, and 1991-1993. Results indicated that (a) low family SES was associated with risk for offspring anxiety, depressive, disruptive, and personality disorders after offspring IQ and parental psychopathology were controlled, and (b) offspring disruptive and substance use disorders were associated with risk for poor educational attainment after offspring IQ and parental psychopathology were controlled. These findings indicate that social causation and social selection processes vary in importance among different categories of psychiatric disorders.

Adolescent↗

PubMed1999

Rodent fibroblast model for studies of response of malignant cells to exogenous 5-aminolevulinic acid.

All nucleated mammalian cells synthesize protoporphyrin IX (PpIX) when exposed to exogenous 5-aminolevulinic acid (ALA). The response to exogenous ALA under standard conditions (the ALA phenotype) is characteristic for each cell type. Significantly more PpIX accumulates in malignant and premalignant cells than in the normal cells from which they were derived. A rodent fibroblast model was developed to study the mechanisms responsible for this phenomenon. Exogenous ALA induced the accumulation of substantial concentrations of PpIX in fibrosarcoma cells, and in immortalized fibroblasts transfected with the oncogene c-myc, IGF-1 receptor, IGF-1 and its receptor, v-fos, v-raf, v-Ki-ras, v-abl, or polyomavirus middle T antigen with G418 resistance selection. Much lower concentrations of PpIX accumulated in primary fibroblast cultures, in immortalized fibroblast cell lines, and in immortalized fibroblasts transfected with the G418-resistance gene only. The mechanisms responsible for the increased accumulation of ALA-induced PpIX by transformed cells (the malignant ALA phenotype) therefore appear to be closely linked to the mechanisms responsible for malignant transformation. Identification of the nature of that linkage may lead to new approaches to cancer therapy.

3T3 Cells↗

PubMed1999

The effect of age, diabetes, and other comorbidity on the survival of patients on dialysis: a systematic quantitative overview of the literature.

BACKGROUND: The UK Renal Registry quotes a 1-year death rate for patients established on dialysis of 19.4 per 100 patient years. Clinical experience, reflected in the UK Renal Association Standards Document (RASD), recognizes qualitatively that age, diabetes, and other comorbidities increase the risk of death. The aim of this paper is to provide quantitative estimates of the relative risk of death associated with particular patient characteristics. METHODS: Quantitative techniques were used to estimate relative risk of death in the seven studies quoted in the RASD document and 17 other papers identified in a systematic literature search. Relative risk data from each study were pooled using a fixed effects model (f). A random effects model (r) was applied to pool relative risks if heterogeneity was found to exist between studies. A meta-regression analysis was also carried out to investigate whether study covariates substantially explained the heterogeneity between studies. RESULTS: Pooling the papers identified in the systematic literature search with those from the RASD gave rise to a relative risk of death of 1.029 (95% CI 1.013-1.045) (r) associated with each year's increase in age. The relative risk associated with the presence of diabetes was 1.91 (95% CI 1.67-2.17) (r), whilst that associated with heart disease was 1.59 (95% CI 1.49-1.69) (f), and with peripheral vascular disease 1.58 (95% CI 1.29-1.93) (r). Heterogeneity was found in the estimates of risk associated with age, diabetes, and peripheral vascular disease. Important study covariates included the use of incident or prevalent cases, the use of routine data sources or data collected specifically for a particular study, the country in which the study was located, the use of a P value to infer the standard error of a relative risk estimate in a particular study, and the method of classifying diabetes. CONCLUSIONS: Published studies can be used to quantify the relative risk of death for dialysis patients with various comorbidities. This information is important if attempts are to be made to set standards for the performance of dialysis units, and to compare the performance of one dialysis unit with that of another.

Aging↗

PubMed1999

Psychiatric comorbidity among adolescents with substance use disorders: findings from the MECA Study.

OBJECTIVE: To investigate the extent to which adolescents in the community with current substance use disorders (SUD) experience co-occurring psychiatric disorders. METHOD: Diagnostic data were obtained from probability samples of 401 children and adolescents, aged 14 to 17 years, and their mothers/caretakers, who participated in the Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study. RESULTS: The rates of mood and disruptive behavior disorders are much higher among adolescents with current SUD than among adolescents without SUD. Comparison with adult samples suggests that the rates of current comorbidity of SUD with psychiatric disorders are the same among adolescents as adults, and lower for lifetime disruptive disorders/antisocial personality disorder among adolescents than adults. CONCLUSIONS: The high rate of coexisting psychiatric disorders among adolescents with SUD in the community needs to be taken into account in prevention and treatment programs.

Adolescent↗

PubMed1999

Childhood abuse and neglect: specificity of effects on adolescent and young adult depression and suicidality.

OBJECTIVE: To investigate the magnitude and independence of the effects of childhood neglect, physical abuse, and sexual abuse on adolescent and adult depression and suicidal behavior. METHOD: A cohort of 776 randomly selected children was studied from a mean age of 5 years to adulthood in 1975, 1983, 1986, and 1992 during a 17-year period. Assessments included a range of child, family, and environmental risks and psychiatric disorders. A history of abuse was determined by official abuse records and by retrospective self-report in early adulthood on 639 youths. Attrition rate since 1983 has been less than 5%. RESULTS: Adolescents and young adults with a history of childhood maltreatment were 3 times more likely to become depressed or suicidal compared with individuals without such a history (p < .01). Adverse contextual factors, including family environment, parent and child characteristics, accounted for much of the increased risk for depressive disorders and suicide attempts in adolescence but not in adulthood (p < .01). The effects of childhood sexual abuse were largest and most independent of associated factors. Risk of repeated suicide attempts was 8 times greater for youths with a sexual abuse history (odds ratio = 8.40, p < .01). CONCLUSIONS: Individuals with a history of sexual abuse are at greater risk of becoming depressed or suicidal during adolescence and young adulthood. Adolescence is the most vulnerable period for those youths who may attempt suicide repeatedly. Many of the apparent effects of neglect, in contrast, may be attributable to a range of contextual factors, suggesting broader focus for intervention in these cases.

Adolescent↗

PubMed1999

Influence of child and adolescent psychiatric disorders on young adult personality disorder.

OBJECTIVE: This study examines associations between childhood psychopathology and young adult personality disorder in a random sample of 551 youths, who were 9 to 16 years old at first assessment. METHOD: Subjects were evaluated for DSM-III-R psychiatric disorders. Information was obtained prospectively from youths and their mothers at three points over 10 years. The predictive effects of prior axis I disorders and adolescent axis II personality disorder clusters A, B, and C on young adult personality disorder were examined in logistic regression analyses. RESULTS: The odds of young adult personality disorder increased given an adolescent personality disorder in the same cluster. Prior disruptive disorders, anxiety disorders, and major depression all significantly increased the odds of young adult personality disorder independent of an adolescent personality disorder. In addition, comorbidity of axis I and axis II disorders heightened the odds of young adult personality disorder relative to the odds of a disorder on a single axis. CONCLUSIONS: Assessment of personality pathology before late adolescence may be warranted. Childhood or adolescent axis I disorders may set in motion a chain of maladaptive behaviors and environmental responses that foster more persistent psychopathology over time. Identification and treatment of childhood disorder may help to reduce that risk.

Adolescent↗

PubMed1998

Visualization of specific B and T lymphocyte interactions in the lymph node.

Early events in the humoral immune response were visualized in lymph nodes by simultaneous tracking of antigen-specific CD4 T and B cells after immunization. The T cells were initially activated in the T cell areas when the B cells were still randomly dispersed in the B cell-rich follicles. Both populations then migrated to the edges of the follicles and interacted there, resulting in CD154-dependent B cell proliferation and germinal center formation. These results provide visual documentation of cognate T-B cell interactions and localize them to the follicular border.

Adoptive Transfer↗

PubMed1998

A longitudinal analysis of risk factors for child maltreatment: findings of a 17-year prospective study of officially recorded and self-reported child abuse and neglect.

OBJECTIVE: To identify demographic, family, parent, and child factors prospectively associated with risk for child abuse and neglect among families in the community, using data on child maltreatment obtained from both official records and youth self-reports. METHOD: Surveys assessing demographic variables, family relationships, parental behavior, and characteristics of parents and children were administered to a representative sample of 644 families in upstate New York on four occasions between 1975 and 1992. Data on child abuse and neglect were obtained from New York State records and retrospective self-report instruments administered when youths were > or = 18 years old. RESULTS: Logistic regression analyses indicated that different patterns of risk factors predicted the occurrence of physical abuse, sexual abuse, and neglect, although maternal youth and maternal sociopathy predicted the occurrence of all three forms of child maltreatment. In addition, the prevalence of child abuse or neglect increased from 3% when no risk factors were present to 24% when > or = 4 risk factors were present. State records and self-reports of child maltreatment did not correspond in most cases when maltreatment was reported through at least one data source, underlining the importance of obtaining data from both official records and self-reports. CONCLUSIONS: Assessment of a number of risk factors may permit health professionals to identify parents and children who are at high risk for child maltreatment, facilitating appropriate implementation of prevention and treatment interventions.

Child↗

PubMed1998

Barriers to the uptake of cataract surgery.

In The Gambia many patients identified as blind or as having low vision are not attending for surgery. The aim of this study was to investigate the reasons for non-attendance. Three methods were used: semi-structured interviews; focus group discussions; and written questionnaires completed by staff. The most frequently identified barrier by all three methods was cost, closely followed by lack of information about services, fear, transport difficulties, and the lack of an escort. In addition to the existing measures taken by the National Eye Care Programme (NECP) to reduce these barriers, further research into both the public's knowledge and attitudes regarding surgery for cataract is needed. More contact between members of the eye care programme and the communities would aid the transfer of information about the surgery.

Cataract Extraction↗

PubMed1998

Attributions for positive life events predict recovery from depression among psychiatric inpatients: an investigation of the Needles and Abramson model of recovery from depression.

The authors investigated whether attributions for positive life events predict decreases in hopelessness and depressive symptoms among clinically depressed adults. Measures of attributional style, attributions for recent events, depressive symptoms, dysfunctional attitudes, hopelessness, and life events were administered to 52 depressed psychiatric inpatients treated with antidepressant medication; the measures were readministered 12 and 24 days later. Results indicated that (a) internal, stable, global attributions for recent positive events mediated a significant association between attributional style for positive life events and decreased hopelessness; (b) decreases in hopelessness mediated a significant association between internal, stable, global attributions for recent positive events and decreases in depressive symptom levels; and (c) depressotypic cognitions were not associated with decreases in either hopelessness or depressive symptom levels.

Adolescent↗

PubMed1997

Psychiatric disorders associated with substance use among children and adolescents: findings from the Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study.

The relationships between specific quantities and frequencies of alcohol, cigarette, and illicit substance use and substance use (SUD) and other psychiatric disorders were investigated among 1,285 randomly selected children and adolescents, aged 9 to 18, and their parents, from the Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study. Logistic regressions indicated that daily cigarette smoking, weekly alcohol consumption, and any illicit substance use in the past year were each independently associated with an elevated likelihood of diagnosis with SUD and other psychiatric disorders (anxiety, mood, or disruptive behavior disorders), controlling for sociodemographic characteristics (age, gender, ethnicity, family income). The associations between the use of specific substances and specific psychiatric disorders varied as a function of gender.

Adolescent↗

PubMed1997

Stability and change in personality disorder symptomatology: findings from a longitudinal study of HIV+ and HIV- men.

A longitudinal study was conducted to investigate the stability of personality disorders (PDs) over a 2-year interval, as well as the association between change in PD symptomatology and change in psychological distress. Structured clinical interviews and questionnaires assessing PDs and psychological distress were administered to a community sample of 118 gay men (80 HIV seropositive men and 38 HIV seronegative men) at a baseline session and readministered 2 years later. Results indicated that PD symptom levels tended to be moderately stable, that PD diagnoses had low stability and that changes in PD symptom levels were associated with changing levels of psychological distress but not with progression of HIV infection.

Adult↗

PubMed1997

Use of adoptive transfer of T-cell-antigen-receptor-transgenic T cell for the study of T-cell activation in vivo.

Adoptive transfer of TCR-transgenic T cells uniformly expressing an identifiable TCR of known peptide/MHC specificity can be used to monitor the in vivo behavior of antigen-specific T cells. We have used this system to show that naive T cells are initially activated within the T-cell zones of secondary lymphoid tissue to proliferate in a B7-dependent manner. If adjuvants or inflammatory cytokines are present during this period, enhanced numbers of T cells accumulate, migrate into B-cell-rich follicles, and acquire the capacity to produce IFN-gamma and help B cells produce IgG2a. If inflammation is absent, most of the initially activated antigen-specific T cells disappear without entering the follicles, and the survivors are poor producers of IL-2 and IFN-gamma. Our results indicate that inflammatory mediators play a key role in regulating the anatomic location, clonal expansion, survival and lymphokine production potential of antigen-stimulated T cells in vivo.

Adjuvants, Immunologic↗

PubMed1997

Adolescent personality disorder symptoms mediate the relationship between perceived parental behavior and Axis I symptomatology.

A study was conducted to investigate whether adolescent personality disorder symptoms mediate the relationship between perceived parental behavior and Axis I psychiatric symptomatology. The Parental Behavior Form, Personality Diagnostic Questionnaire-Revised, and Revised Hopkins Symptom Checklist (SCL-90-R) were administered to 187 first-year undergraduate students during their first week of college enrollment. One hundred fifty seven participants were readministered the SCL-90-R two months later. Results of correlational and hierarchical multiple regression analyses indicated that: (1) Adolescents' perceptions of parental acceptance/nurturance and harsh, controlling parental behavior were associated with baseline personality disorder symptom levels. (2) Perceived harsh parental control predicted both baseline and follow-up Axis I symptomatology. (3) In turn, baseline personality disorder symptoms were associated with Axis I symptom levels, both at baseline and at follow-up assessment after baseline Axis symptoms were accounted for. (4) Perceived parental behavior did not predict baseline or subsequent Axis I symptomatology after personality disorder symptom levels were accounted for. The present findings thus indicate that personality disorder symptoms completely mediated the relationship between adolescent perceptions of harsh, controlling parental behavior and Axis I psychiatric symptomatology.

Adolescent↗

PubMed1996

Personality disorders predict onset of Axis I disorders and impaired functioning among homosexual men with and at risk of HIV infection.

BACKGROUND: A longitudinal study was conducted to investigate whether personality disorders (PDs) increase risk for the development of future Axis I disorders and serious functional impairment among human immunodeficiency virus (HIV)-seropositive and HIV-seronegative homosexual men. METHOD: Baseline assessments of PDs, Axis I disorders and symptoms, and Global Assessments of Functioning were conducted with a community sample of 107 (66 HIV-positive and 41 HIV-negative) homosexual men participating in a longitudinal study with semiannual interviews over 3 years. RESULTS: Logistic regression analysis indicated that PDs predicted onset of subsequent Axis I disorders after controlling for both HIV status and lifetime Axis I history (adjusted odds ratio, 4.31; P=.01; 95% confidence interval, 1.39 to 13.32). Of the 21 participants with PDs, 16 (76%) were subsequently diagnosed with Axis I disorders on at least one occasion. By contrast, only 36 (42%) of the 86 participants without PDs were subsequently diagnosed with Axis I disorders. Further, 33% of the participants with PDs, in comparison with only 8% of those without PDs, were assigned Global Assessments of Functioning scores of 50 or lower, indicating serious impairment during the postbaseline study period (adjusted odds ratio, 5.70; P<.005; 95% confidence interval, 1.66 to 19.53). CONCLUSION: Personality disorders may contribute to increased risk for onset of Axis I disorders and serious impairment among homosexual men regardless of HIV serologic status.

Adult↗