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Biomedical subjects

C L Park

Publications and source records attributed to C L Park.

At least 19 recordsLinked to original sources
PubMed2001

Appraisals of controllability and coping in caregivers and HIV+ men: testing the goodness-of-fit hypothesis.

The authors examined goodness of fit between controllability appraisals and coping in 82 HIV+ and 162 HIV-gay men experiencing the chronic stress of caregiving and 61 HIV+ gay men who were not caregiving. Multiple assessments of each individual over a 2-year period allowed replication of prior cross-sectional research examining goodness of fit, as well as the creation of intraindividual goodness-of-fit scores that were then used to examine within-person fluctuations in goodness of fit over time and goodness of fit as an individual difference variable related to adjustment. Results indicate that the importance of goodness of fit varies for different kinds of coping: The concept was supported for problem-focused coping and, to a lesser extent, for emotion-focused coping but not for meaning-focused coping. Within-subject variation in goodness of fit was related to within-subject variation in depressed mood, but between-subjects variation (individual differences) in fit was not associated with depressed mood, suggesting that goodness of fit is better understood as a transactional variable than as a personality or "coping style" variable.

Adaptation, Psychological↗
PubMed1998

Temporal organization in children's strategy formation.

It is well established that children use study behaviors such as card sorting, category naming, and item-by-item rehearsal to assist subsequent word recall. In this article, we provide evidence that these behaviors are organized into coherent temporal patterns. Fourier analyses of individual behaviors over a sequence of five consecutive study/recall trials indicated that sorting was synchronized with the start of each trial, whereas rehearsal tended to occur later in each trial. Fourier analyses of pairs of behaviors indicated that sorting and category naming, both concerned with categorization of the to-be-remembered words, co-occurred early in each trial at a greater rate than expected based on their individual frequencies of occurrence (i.e., they were used cooperatively). In contrast, verbal rehearsal of individual words co-occurred with both sorting and category naming at a lesser rate than would be expected based on their individual frequencies of occurrence. The results thus point to a global strategy in which children learn the items' categories before they learn them individually. There was little apparent qualitative difference in temporal organization for second- and fourth-grade children. However, sorting early in each trial was more pronounced for children with better word recall (regardless of grade), and the suppressed co-occurrence of rehearsal with sorting and category naming (i.e., keeping category learning temporally separate from item learning) was more pronounced for the fourth-grade children.

Child↗
PubMed1998

Neuropeptide Y inhibits ciliary beat frequency in human ciliated cells via nPKC, independently of PKA.

The intracellular mechanisms whereby the inhibitory neurotransmitter neuropeptide Y (NPY) decreases ciliary beat frequency (CBF) were investigated in cultured human tracheal and bronchial ciliated cells. CBF was measured by nonstationary analysis laser light scattering. NPY at 1 and 10 microM decreased CBF from a baseline of 6.7 +/- 0.5 (n = 12) to 6.1 +/- 0.5 (P < 0.05) and 5.8 +/- 0.4 (P < 0.01) Hz, respectively. Prior application of PYX-1, an NPY antagonist, prevented the decreases of CBF induced by both doses of NPY. Two broad protein kinase C (PKC) kinase inhibitors, staurosporine and calphostin C, also abolished the NPY-induced decrease in CBF. The NPY-induced decrease in CBF was abolished by GF 109203X, a novel PKC (nPKC) isoform inhibitor, whereas this decrease in CBF was not attenuated by Gö-6976, a specific inhibitor of conventional PKC isoforms. Because pretreatment with NPY did not block the stimulation of CBF by forskolin and pretreatment with forskolin did not abolish the NPY-induced inhibition of CBF, this NPY receptor-mediated signal transduction mechanism appears to be independent of the adenylate cyclase-protein kinase A (PKA) pathway. Inhibition of Ca2+-ATPase by thapsigargin also prevented the suppression of CBF induced by subsequent application of NPY. These novel data indicate that, in cultured human epithelia, NPY decreases CBF below its basal level via the activation of an nPKC isoform and Ca2+-ATPase, independent of the activity of PKA. This is consistent with the proposition that NPY is an autonomic efferent inhibitory neurotransmitter regulating mucociliary transport.

Adenylyl Cyclases↗
PubMed1998

Does influenza vaccination exacerbate asthma?

A few anecdotal reports have described serious asthma exacerbations following influenza vaccination. However, a causal relationship has not been clearly established since the vaccine is administered at the time of year when the background incidence of asthma exacerbation is high. Some reports describing minor pulmonary function changes or increased bronchial reactivity in patients with asthma receiving influenza vaccination did not include placebo controls and the results as they are reported are difficult to interpret. Results from several placebo-controlled studies, open trials, and US and European postmarketing surveillance data have shown no evidence of asthma exacerbation related to killed influenza vaccination, although 1 recent placebo-controlled study demonstrated a decrease in peak flow in a small number of first-time vaccinees without clinical exacerbation of asthma. A recent report demonstrated that a group of children with acute asthma exacerbation tolerated influenza vaccination to the same degree as patients with stable asthma. Thus, a plethora of evidence indicates that killed-subunit influenza vaccination is well tolerated and does not exacerbate asthma to a clinically significant degree. Limited experience with live influenza vaccine also suggests that it may be safely given to patients with asthma. Although vaccine efficacy has not been unequivocally demonstrated in patients with asthma, the potential benefits from prevention of morbidity associated with influenza infection in these patients outweighs the theoretical concerns over the safety of influenza vaccination.

Adult↗
PubMed1997

Hemoglobin-specific antibody in a multiply transfused patient with sickle cell disease.

Human hemoglobins (Hbs) are known to be immunogenic, and both normal and variant forms of Hb have been shown to stimulate antibody formation in a variety of animal species. In patients who are homozygous for the sickle Hb (HbS) mutation, transfusion of normal, HbA-containing erythrocytes provides a potential stimulus for HbA alloimmunization. We tested serum samples for the presence of anti-Hb antibody by a solid-phase enzyme-linked immunosorbent assay (ELISA) using Hb-coated polystyrene microtiter plates. Hb-bound antibody was identified using an antihuman IgG antibody. Serum samples from 89 patients with sickle cell disease were initially tested for evidence of Hb antibody. The serum from three individuals exhibited antibody activity against HbA with little or no activity against HbS. Only one of them, a multiply transfused adult with HbSS, was available for further study. When this patient's antibody was tested against a variety of normal and mutant Hbs using antibody either to human IgG or to kappa chains, the anti-Hb antibody demonstrated specificity for the region of the Hb beta chain corresponding to the site of the amino acid substitution of HbS. The level of activity of the patient's anti-HbA showed no significant change over 1.5 years of observation. The transfusion of erythrocytes containing Hb structurally different from that of the recipient appeared to be capable of stimulating the production of Hb-specific alloimmune antibody.

Adult↗
PubMed1997

A pilot exploratory study of oral electrical stimulation on swallow function following stroke: an innovative technique.

This pilot study investigated the effect of oral electrical stimulation on swallow function in stroke patients with chronic dysphagia. The purpose was to determine whether an innovative technique could make an improvement in swallow function that might be developed as a potential treatment for patients with persistent dysphagia. Four stroke patients with chronic dysphagia were recruited on the basis of videofluoroscopic findings of a delayed swallow reflex. A single case design was used. Oral electrical stimulation of swallowing was carried out using a palatal prosthesis starting at an output pulse of 0.5 mA, with a fixed duration of 200 microsec, repeated at 1-sec intervals. Barium paste (1 x 5 ml) was introduced at the level of the patient's maximum tolerance of stimulation and any effect on swallow function was recorded by videofluoroscopy. The findings from the pilot study indicated that oral electrical stimulation resulted in an improvement in swallow function in 2 of the 4 patients. The stimulation was well tolerated in all cases with no serious adverse effects. These early results are promising, but further research is needed.

Aged↗
PubMed1997

The natural history of dysphagia following a stroke.

To assess the frequency and natural history of swallowing problems following an acute stroke, 121 consecutive patients admitted within 24 hours of the onset of their stroke were studied prospectively. The ability to swallow was assessed repeatedly by a physician, a speech and language therapist, and by videofluoroscopy. Clinically 51% (61/121) of patients were assessed as being at risk of aspiration on admission. Many swallowing problems resolved over the first 7 days, through 28/110 (27%) were still considered at risk by the physician. Over a 6-month period, most problems had resolved, but some patients had persistent difficulties (6, 8%), and a few (2, 3% at 6 months) had developed swallowing problems. Ninety-five patients underwent videofluoroscopic examination within a median time of 2 days; 21 (22%) were aspirating. At 1 month a repeat examination showed that 12 (15%) were aspirating. Only 4 of these were persistent; the remaining 8 had not been previously identified. This study has confirmed that swallowing problems following acute stroke are common, and it has been documented that the dysphagia may persist, recur in some patients, or develop in others later in the history of their stroke.

Aged↗
PubMed1997

The roles of constructive thinking and optimism in psychological and behavioral adjustment during pregnancy.

This study examined the impact of constructive thinking on the anxiety, positive states of mind, and substance use of 221 women during pregnancy and the influence of optimism and perceived stress on these relationships. Participants were interviewed both early and late in pregnancy. Constructive thinking predicted both psychological and behavioral adjustment later in pregnancy, independent of age and social desirability. Subsequent path analyses indicated that constructive thinking mediated the impact of optimism on anxiety, positive states of mind, and substance use during pregnancy. In turn, the effect of constructive thinking on women's adjustment during pregnancy was itself mediated by their perceived stress. Implications for constructive thinking and optimism as independent constructs relevant to adjustment and their potential importance for future research and clinical applications are discussed.

Adaptation, Psychological↗
PubMed1997

Stability and change in psychosocial resources during caregiving and bereavement in partners of men with AIDS.

This study examines the effects of caregiving and bereavement on psychosocial resources in HIV+ and HIV- caregivers of men with AIDS. We explored three hypotheses regarding these effects: the "wear and tear" hypothesis, which asserts that the chronic stress of caregiving and bereavement diminishes resources; the "enhancement" hypothesis, which asserts that caregiver resources may increase in response to increased demands; and the "personality" hypothesis, which asserts that psychosocial resources reflect stable personality characteristics. We addressed four questions: (a) What are the effects of caregiving on resources? (b) How do these resources vary by the imminence of the partner's death? (c) What is the effect of the partner's death on these resources? and (d) How does the caregivers' HIV serostatus influence the effects of caregiving and bereavement on resources? Support for the personality hypothesis predominated, with some support for the wear and tear hypothesis, depending on the resource in question. In general, HIV seropositivity did not put people at additional risk for resource depletion.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Assessment and prediction of stress-related growth.

This article reports the development of the Stress-Related Growth Scale (SRGS) and its use in a study examining determinants of stress-related positive outcomes for college students. Study 1 analyses showed that the SRGS has acceptable internal and test-retest reliability and that scores are not influenced by social desirability. Study 2 analyses showed that college students' SRGS responses were significantly related to those provided by friends and relatives on their behalf. Study 3 analyses tested the determinants of stress-related growth longitudinally. Significant predictors of the SRGS were (a) intrinsic religiousness; (b) social support satisfaction; (c) stressfulness of the negative event; (d) positive reinterpretation and acceptance coping; and (e) number of recent positive life events. The SRGS was also positively related to residual change in optimism, positive affectivity, number of socially supportive others, and social support satisfaction, lending further support to the validity of this new scale. Results have implications for current theory on stress-related positive outcomes.

Adaptation, Psychological↗
PubMed1996

Influenza vaccination of children during acute asthma exacerbation and concurrent prednisone therapy.

OBJECTIVES: The influenza vaccination rate is very low among children with moderate to severe asthma. This may be partly because of poor patient motivation and failure to visit clinics for vaccination. Another important factor may be health care providers' deferral of vaccination because of concern about the efficacy and safety of influenza vaccination during asthma exacerbations and concurrent prednisone therapy. We therefore examined the safety and immunogenicity of influenza vaccination during acute asthma exacerbation with concomitant prednisone therapy. SETTING: A pediatric allergy and pulmonology clinic and a pediatric emergency department. DESIGN: Children (n = 109) with a known diagnosis of asthma 6 months to 18 years of age were recruited. All participating patients, 59 without asthma symptoms (no prednisone, control group) and 50 with acute asthma exacerbation requiring prednisone burst therapy (prednisone group) received trivalent subvirion influenza vaccine. Fifteen children in the control group and 12 in the prednisone group received a booster dose according to American Academy of Pediatrics guidelines. Serum antibody titers to influenza A/Beijing/32/92 (H3N2), influenza A/Texas/36/91 (H1N1), and influenza B/Panama/45/90 were measured before and 2 weeks after vaccination. Adverse effects noted within 48 hours after vaccine dose were ascertained during the follow-up visit. RESULTS: The antibody response was analyzed by comparing mean postvaccine titers, the percentage of patients achieving protective antibody levels (> or = 5log2), and the percentage of patients achieving rises in titers of 2log2 or greater. Antibody responses to influenza A/Beijing/32/92 (H3N2) and influenza A/Texas/36/91 (H1N1) in the prednisone-treated and control groups were not different. A significantly better response to the influenza B/Panama/45/90 antigen was seen in the prednisone group for all three parameters. Children who received a booster dose and the subgroup of children with low prevaccination titers (< or = 3log2) showed similar patterns. Adverse effects, including asthma exacerbation, local swelling at the injection site, fever, rash, and headache, were not different in the two groups. CONCLUSIONS: Influenza vaccination can be given safely and effectively to asthmatic children regardless of asthma symptoms or concurrent prednisone therapy when necessary. Vaccination of all moderate to severe asthmatic patients visiting clinics or emergency departments would improve the overall vaccination rate significantly.

Antibodies, Viral↗
PubMed1992

Phase I study of busulfan, cyclophosphamide, and timed sequential escalating doses of cytarabine followed by bone marrow transplantation.

In both animal models and human studies in leukemia, residual disease on day 8 following myelosuppressive therapy is in a proliferative phase and therefore may be sensitive to the S-phase specific drug cytarabine. Based on this concept, 17 patients with refractory or relapsed leukemia or lymphoma undergoing either autologous or allogeneic bone marrow transplantation (BMT) were treated on a Phase I protocol using high doses of busulfan (16 mg/kg, days -10, -9, -8, -7) and cyclophosphamide (120 mg/kg, days -6, -5) followed by escalating doses of a 48-h continuous infusion of cytarabine (starting dose 1000 mg/m2/48 h, days -3, -2). Ten patients received autologous transplants (two with Hodgkin's disease, seven with non-Hodgkin's lymphoma, one with chronic myelogenous leukemia (CML) in blast phase). Seven received allogeneic BMT (two with refractory acute myelocytic leukemia (AML), one with refractory acute lymphoblastic leukemia (ALL) undergoing a second BMT, one with Burkitt's-type leukemia, one with ALL in fifth relapse and two with CML in accelerated/blast phase). Two of these patients received a T cell-depleted haploidentical transplant. The maximum tolerated dose of cytarabine was 1500 mg/m2/48 h; a pulmonary syndrome including dyspnea, hypoxemia, and interstitial infiltrates which responded to aggressive diuresis was the dose limiting toxicity. Of the 10 patients who received cytarabine doses of 2000 or 2500 mg/m2/48 h, five patients developed adult respiratory distress syndrome (ARDS) with three patients requiring intubation; two recovered. Of the nine patients with lymphoma, seven responded with complete tumor clearance (CTC) with two patients tumor-free 13 and 15 months post-BMT, one remained refractory and one died too early to evaluate (TETE).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Massive intravascular hemolysis associated with intravenous immunoglobulin in bone marrow transplant recipients.

We report two group B Rho(D)-positive bone marrow transplant recipients who had sudden onset of massive intravascular hemolysis following the use of intravenous immunoglobulin (i.v. Ig). The first case developed chills and hypotension followed by hemoglobinuria with the first infusion of i.v. Ig. More severe symptoms occurred when infusion was reattempted. The second case developed hemoglobinuria without other symptomatology. In both patients, direct and indirect antiglobulin tests became positive following the use of i.v. Ig. Sera and eluates demonstrated IgG anti-B. Samples of i.v. Ig received by both patients contained both anti-B and anti-A and were incompatible with patients' red blood cells. These serologic findings indicate acute hemolysis secondary to the presence of IgG anti-B in i.v. Ig preparations.

ABO Blood-Group System↗
PubMed1987

Transmission of human immunodeficiency virus from parents to only one dizygotic twin.

The acquired immunodeficiency syndrome-related complex was identified in a mother and one of her nonidentical twins. Generalized lymphadenopathy was first noted in the infant at age 17 months, and that of the mother was incidentally discovered 6 months later. The father, who had had homosexual contacts before the conception of the twins, appeared to be in good health. No one in the family had constitutional symptoms or showed signs of opportunistic infection. Both parents and the patient had hypergammaglobulinemia, low T-helper-to-suppressor-cell ratio, and positive serum antibody to human immunodeficiency virus. Attempts to isolate the virus from all family members were unsuccessful. The twin brother was in good health with a normal immunologic profile and negative antibody to human immunodeficiency virus.

AIDS-Related Complex↗
PubMed1986

Childhood common variable immunodeficiency with autoimmune disease.

Clinical and laboratory findings in eight patients with childhood common variable immunodeficiency and autoimmune disease are described. Six of the eight patients had initial signs of the disease, persistent secretory diarrhea, recurrent upper respiratory tract infections, or both, in the first year of life. Autoimmune manifestations included idiopathic thrombocytopenia (4/8), hemolytic anemia (3/8), secretory diarrhea (4/8), arthritis (2/8), chronic active hepatitis (2/8), parotitis (2/8), and Guillain-Barré syndrome (2/8). In addition to the expected sinusitis, otitis, and pneumonia caused by encapsulated bacteria, these patients also had severe infections with viruses of the herpes group. Most of these patients had lymphadenopathy, splenomegaly, growth failure, and failure to develop secondary sexual characteristics. Laboratory studies demonstrated a significant increase in the ratio of T cells expressing the T helper phenotype (OKT4) to T cells expressing the T suppressor-cytotoxic phenotype (OKT8) (T4/T8). This increase could be attributed to a decrease in the absolute number of T8 cells. Additional findings included fluctuating levels of serum immunoglobulins and markedly diminished in vitro antibody production by B cells. The clinical course was relapsing and remitting, and dominated by the autoimmune manifestations of the disease. This group of patients constitutes a distinct subset of children with hypogammaglobulinemia, a subset with a complex, multisystemic disorder associated with significant morbidity and mortality.

Adolescent↗
PubMed1983

Identification of a B cell differentiation factor(s) spontaneously produced by proliferating T cells in murine lupus strains of the lpr/lpr genotype.

Lymph node and spleen cells of the autoimmune MRL/Mp-lpr/lpr mouse strain spontaneously produce (in the absence of mitogenic stimulation) a factor(s) that induces B cell differentiation. This factor is not produced by the congenic MRL/n mouse strain that lacks the lpr gene or by normal mouse strains. However, lymphoid cells of the B6-lpr/lpr (B6/1) strain also produce a B cell differentiation factor. Although the factor acts on resting B cells, its effect is greatly magnified by activating the B cells with anti-mu or lipopolysaccharide. MRL/l mice begin producing the factor as early as 1 mo of age but levels increase with age and appearance of lymphoproliferation. Cell depletion studies reveal that this factor is produced by T cells of the Lyt-1+2-phenotype. Because of its association with the lpr/lpr genotype, we term this B cell differentiation factor L-BCDF. Functional analysis of L-BCDF reveals that it acts regardless of cell density in culture and in the absence of interleukin 2 (IL-2). In fact, the increase in the production of L-BCDF by MRL/1 T cells with aging occurs concomitantly with a marked decrease in their ability to produce IL-2. No T cell replacing factor activity or B cell growth factor-like activity can be detected in MRL/l-derived supernatants. L-BCDF induces both IgM and IgG synthesis in lipopolysaccharide-activated B cells; however, it has a greater effect on IgG secretion. In particular, the production of IgG1, IgG2a, and IgG2b are markedly enhanced in the presence of L-BCDF. The spontaneous production of L-BCDF by T cells of SLE mice of lpr/lpr genotype suggests an association of this factor with autoimmunity.

Aging↗