PubMed Health⌕ Search

Biomedical subjects

J L Wong

Publications and source records attributed to J L Wong.

At least 19 recordsLinked to original sources
PubMed2005

Encapsulation in sub-micron species: a short review and alternate strategy for dye encapsulation.

The encapsulation of molecular species has received considerable attention in recent years. Polymers, dendrimers and microemulsions along with other systems have been used as precursors for the synthesis of encapsulating agents. Especially important in this field is the core-shell architecture. This structure offers the encapsulated species an extra level of protection due to the presence of a shell, covering the interior of a capsule. Dyes, porphyrines, drugs, cells and other active agents have been successfully encapsulated, and the host-guest interaction has been studied by various experimental techniques. A review is new provided of the progress made in this field in the last several years is presented. Different classes of synthetic approaches are presented and resulting encapsulation studies are summarised. An approach to the encapsulation of dansyl chloride dye in core-shell nanoparticles is also presented.

Coated Materials, Biocompatible↗
PubMed2004

Lysine conjugate of acrylonitrile as antigenic sites in hemoglobin adducts.

For biomonitoring environmental exposure to acrylonitrile (AN), a monoclonal antibody (mAb) A2D1, was developed to recognize specifically the hemoglobin (Hb) adduct, Hb-AN, but not Hb itself. This appears to be the first example that a small molecule-like AN may introduce new antigenicity into hemoglobin, which already exhibits multiple antigenic determinants. This report addresses the localization of the newly formed antigenic sites in human Hb-AN. As antigenic probes, the AN conjugates of 10 amino acids, six dipeptides, and four tripeptides were prepared as monitored by 1H NMR, and their antigenicity was evaluated by competitive inhibition immunoassay. A Lys-epsilonNH-AN was found essential to inhibiting activity. The potent peptide-AN inhibitors, containing a sequence of His and Lys, showed IC50 at the micromolar concentration, thus implicating human Hbalpha-89,90 and Hbbeta-143,144 in the distal heme pocket region as the new antigenic sites.

Acrylonitrile↗
PubMed2001

Subspeciation of nickel disulfide by carbon paste electrode voltammetry catalyzed by Ni2+.

In subspeciation of sulfidic nickel, carbon paste electrode voltammetry was developed for the specific determination of Ni3S2 or NiS, but NiS2 was found to be unreactive. Ni2+ in pH 7.2 acetate solution was able to catalyze NiS2 to undergo redox reactions. The cyclic voltammogram showed two anodic peaks at -0.3 and +0.7 V and a cathodic peak at -0.6 V. The first anodic peak at -0.3 V and the cathodic peak were common among the three nickel sulfides, but the second anodic peak at +0.7 V was unique to NiS2. This peak current gave a linear dose response to NiS2 from 40 to 610 microg, with a correlation coefficient of 0.994, and a detection limit of 40 microg.

Carbon↗
PubMed2000

Nickel speciation of residual oil fly ash and ambient particulate matter using X-ray absorption spectroscopy.

The chemical speciation of Ni in fly ash produced from approximately 0.85 wt % S residual (no. 6 fuel) oils in laboratory (7 kW)- and utility (400 MW)-scale combustion systems was investigated using X-ray absorption fine structure (XAFS) spectroscopy, X-ray diffraction (XRD), and acetate extraction [1 M NaOAc-0.5 M HOAc (pH 5) at 25 degrees C]-anodic stripping voltammetry (ASV). XAFS was also used to determine the Ni speciation of ambient particulate matter (PM) sampled near the 400-MW system. Based on XAFS analyses of bulk fly ash and their corresponding acetate extraction residue, it is estimated that > 99% of the total Ni (0.38 wt %) in the experimentally produced fly ash occurs as NiSO4.xH2O, whereas > 95% of the total Ni (1.70 and 2.25 wt %) in two fly ash samples from the 400-MW system occurs as NiSO4.xH2O and Ni-bearing spinel, possibly NiFe2O4. Spinel was also detected using XRD. Acetate extracts most of the NiSO4.xH2O and concentrates insoluble NiFe2O4 in extraction residue. Similar to fly ash, ambient PM contains NiSO4.xH2O and NiFe2O4; however, the proportion of NiSO4.xH2O relative to NiFe2O4 is much greater in the PM. Results from this and previous investigations indicate that residual oil ash produced in the 7-kW combustion system lack insoluble Ni (e.g., NiFe2O4) but are enriched in soluble NiSO4.xH2O relative to fly ash from utility-scale systems. This difference in Ni speciation is most likely related to the lack of additive [e.g., Mg(OH)2] injection and residence time in the 7-kW combustion system.

Absorptiometry, Photon↗
PubMed1999

Cognitive and affective improvement in brain dysfunctional patients who achieve inpatient rehabilitation goals.

OBJECTIVE: To evaluate whether improvements in specific cognitive and affective functions are associated with achieving inpatient rehabilitation goals after the acute onset of brain dysfunction. DESIGN: Retrospective analysis of data obtained in a prospective inception cohort study. STUDY SETTING: Medical center and neurological institute. SUBJECTS: Ninety-five heterogeneous brain dysfunctional patients who participated in an interdisciplinary inpatient neurorehabilitation program. Subjects were classified as having achieved their rehabilitation goals (Group 1) or not (Group 2) at time of discharge. MAIN OUTCOME MEASURE: Number of treatment goals attained. RESULTS: Although overall level of performance on the BNI Screen (BNIS) for Higher Cerebral Functions distinguished patients who later achieved their inpatient rehabilitation goals, on admission only performance on the visual spatial subtest was associated with later goal attainment. In contrast, at discharge, patients who showed greater improvement in awareness, affect, visual spatial skills, memory, and attention/concentration were likely to obtain their rehabilitation goals. This was true when the initial level of performance was taken into account. CONCLUSIONS: Measurement of overall neuropsychological status and specific visual spatial abilities at time of admission may help determine which brain dysfunctional patients will obtain inpatient rehabilitation goals. Improvement in a variety of cognitive and affective functions was associated with goal attainment. Early cognitive rehabilitation should focus on both cognitive and affective disturbances to facilitate recovery and rehabilitation outcome.

Analysis of Variance↗
PubMed1999

Sex differences on the MMPI-2 substance abuse scales in psychiatric inpatients.

Sex differences on the MMPI-2 addiction scales (MacAndrew Alcoholism Scale-Revised, Addiction Acknowledgement Scale, Addiction Potential Scale) and their ability to distinguish between substance-abusing and nonabusing psychiatric inpatients were examined. Men obtained higher mean raw scores than women on the MacAndrew Alcoholism Scale-Revised and the Addiction Acknowledgement Scale, and substance abusers scored higher on all three scales. Even relatively low cutoff scores, however, on the MacAndrew Alcoholism Scale-Revised resulted in false negative rates of 37 to 39%. The results support the utility of the MMPI-2 substance abuse scales; however, lower cutoff scores should be used with women and within a psychiatric population.

Adult↗
PubMed1998

Antisense knockdown of inducible nitric oxide synthase inhibits induction of experimental autoimmune encephalomyelitis in SJL/J mice.

We used an antisense oligodeoxynucleotide (ODN) complementary to inducible nitric oxide synthase (iNOS) to inhibit experimental autoimmune encephalomyelitis (EAE) in female SJL/J mice, an animal model for multiple sclerosis. The antisense ODN was administered intraventricularly to mice daily for 10 days beginning at the time of adoptive transfer of myelin basic protein-specific T lymphocytes. The antisense ODN treatment significantly reduced the clinical score of EAE and blocked iNOS mRNA and protein synthesis, as well as iNOS enzyme activity within the central nervous system. The levels of nitric oxide and cyclic guanosine monophosphate were also significantly reduced by the antisense ODN treatment. Neither sense nor random ODN affected clinical EAE or iNOS expression. Moreover, the protein and enzyme activity level of constitutive neuronal nitric oxide synthase was not affected by the antisense ODN. Thus, we have shown that the iNOS antisense ODN specifically blocked iNOS expression and ameliorated the induction of EAE.

Animals↗
PubMed1997

Inducible nitric-oxide synthase and nitric oxide production in human fetal astrocytes and microglia. A kinetic analysis.

The understanding of the induction and regulation of inducible nitric-oxide synthase (iNOS) in human cells may be important in developing therapeutic interventions for inflammatory diseases. In the present study, we not only demonstrated that human fetal mixed glial cultures, as well as enriched microglial cultures, synthesize iNOS and nitric oxide (NO) in response to cytokine stimulation, but also assessed the kinetics of iNOS and NO synthesis in human fetal mixed glial cultures. The iNOS mRNA was expressed within 2 h after stimulation and decreased to base line by 2 days. Significant levels of iNOS protein appeared within 24 h after stimulation and remained elevated during the culture period. A dramatic increase in NO production and NO-mediated events, such as the induction of cyclic guanosine monophosphate (cGMP), NADPH diaphorase activity, and nitrotyrosine occurred 3 days after stimulation, a delay of 48 h from the time of the first expression of iNOS enzyme. This delay of NO production was altered by the addition of tetrahydrobiopterin, but not by the addition of L-arginine, heme, flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN), or NADPH. These findings suggest that a post-translational regulatory event might be involved in iNOS-mediated NO production in human glia.

Astrocytes↗
PubMed1997

Speed of finger tapping and goal attainment after unilateral cerebral vascular accident.

OBJECTIVE: To determine (1) if speed of finger tapping is bilaterally slow after an acute unilateral cerebral vascular accident (CVA) and (2) if speed of finger tapping and grip strength are related to achieving rehabilitation goals during the first few weeks after stroke. DESIGN: Prospective inception cohort study. STUDY SETTING: Medical center and neurological institute. PARTICIPANTS: Fifty-one patients with unilateral CVAs. MAIN OUTCOME MEASURES: Documentation of goal attainment at discharge and bilateral measures of speed of finger tapping and grip strength. RESULTS: Speed of finger tapping and grip strength were often bilaterally below normal limits after an acute unilateral CVA, with the contralateral hand most affected. Speed of finger tapping, but not grip strength, in the ipsilateral hand was associated with achieving rehabilitation goals. Speed of finger tapping in the contralateral hand as well as bilateral grip strength was not related to achievement of rehabilitation goals. CONCLUSIONS: Motor findings suggest that bilateral cerebral dysfunction may be common after an acute unilateral CVA. The speed of finger movement in the hand ipsilateral to the lesion may reflect the degree to which the so-called "unaffected" cerebral hemisphere has in fact maintained its functional integrity. As such, it may be a useful behavioral marker for predicting goal attainment during early stages of neurorehabilitation.

Acute Disease↗
PubMed1997

Prescribed versus actual length of stay and inpatient neurorehabilitation outcome for brain dysfunctional patients.

OBJECTIVE: To determine (1) whether brain dysfunctional patients have better rehabilitation outcomes if they receive prescribed length of stay (LOS) versus less than prescribed and (2) if LOS and cognitive status relate to goal attainment. DESIGN: Prospective inception cohort study. STUDY SETTING: Medical center and a neurological institute. PARTICIPANTS: One hundred six patients with acute static brain lesions. MAIN OUTCOME MEASURES: Documentation of goal attainment at discharge and maintenance of goals 6 months after discharge. All subjects also received neuropsychological tests at admission and discharge. RESULTS: Patients who received prescribed LOS achieved their rehabilitation goals at discharge more frequently than patients who received less than prescribed LOS. There was, however, no difference between groups as to maintenance of rehabilitation goals 6 months after discharge. There was no relation between number of days spent in neurorehabilitation and number of goals achieved at discharge. Cognitive status at discharge was strongly related to achieving rehabilitation goals. CONCLUSION: Although LOS may not specifically relate to goal attainment in a heterogeneous group of brain dysfunctional patients, patients who receive the prescribed LOS and who show notable improvement in cognitive status tend to achieve rehabilitation goals, compared with patients who do not.

Adult↗
PubMed1997

Gender differences of inducible nitric oxide production in SJL/J mice with experimental autoimmune encephalomyelitis.

We identified gender related differences of inducible nitric oxide synthase (iNOS) expression and NO production in mice with experimental autoimmune encephalomyelitis (EAE). When myelin basic protein-specific T-lymphocytes derived from female mice were transferred, the female recipients developed more severe EAE and expressed higher levels of iNOS and NO than male recipients. When the T-lymphocytes derived from males were transferred, severe EAE was induced in neither female or male recipients and neither iNOS nor NO were detectable. These data show an association between No production and EAE severity, suggesting a possible role of NO in the pathogenesis of EAE.

Animals↗
PubMed1996

Antisense blockade of inducible nitric oxide synthase in glial cells derived from adult SJL mice.

Increasing evidence suggests a correlation between cytokine-induced nitric oxide synthase (iNOS) and demyelination in Multiple sclerosis (MS). Inhibition of iNOS may therefore be a novel therapeutic approach in MS. To test an antisense oligodeoxynucleotide (ODN) knockdown strategy for inhibiting iNOS, we used lipopolysaccharide (LPS) together with gamma-interferon (IFN-gamma) to induce iNOS in adult mouse mixed glial cell cultures. We administered an iNOS-derived antisense phosphorothiorate oligodeoxynucleotide (S-ODN) to block the induction. The antisense ODN treatment resulted in significant inhibition of LPS and IFN-gamma induced iNOS mRNA and protein expression. It also inhibited nitric oxide (NO) and cyclic GMP (cGMP) production in a dose dependent fashion. Sense and random S-oligo had no effect in any of these studies. These data indicate the efficacy and specificity of the antisense oligodeoxynucleotide approach in inhibiting iNOS in glial cells.

Animals↗
PubMed1994

Lay theories of psychotherapy and perceptions of therapists: a replication and extension of Furnham and Wardley.

This study examined laypersons' perceptions of psychotherapy, the experience of psychotherapy clients, and therapist credibility. Most of Furnham and Wardley's recent findings of positive and realistic lay views on psychotherapy and therapists were replicated. Age, sex, and psychological experience mediated some beliefs about therapy and clients' experience. Although positive views were associated with higher ratings on some aspects of therapist credibility, only the modality of the therapy (behavior vs. client-centered vs. rational-emotive individual therapy) influenced perceptions of overall credibility. Neither the fee charged nor the participant's sex had any effect on perceptions of therapist credibility.

Adolescent↗
PubMed1994

The stability and prediction of depressive mood states in college students.

Objective criteria for predicting dysphoric mood states in college students from measures of stress and cognitive and personality variables were developed and cross-validated. Contrary to Beck's diathesis-stress model of depression, although dysfunctional attitudes, together with the number and impact of life events, self-esteem problems, and level of traditional feminine personality characteristics, predicted concurrent levels of depressive symptoms, initial level of depression was the best predictor of future depression. Cross-validation of the criteria resulted in accuracy rates of 86 to 87%. Implications of these results and some secondary findings were discussed.

Adolescent↗
PubMed1994

Base rate and simulated symptoms of mild head injury among normals.

This study examined the vulnerability of several self-report instruments commonly used in neuropsychological evaluation - the Iowa Interview for Partial Seiwre-Like Symptoms, Postconcussion Checklist (PCL). Postconcussion Syndrome Checklist (PCSC), and Beck Depression Inventory (BDI) - to exaggerated or feigned complaints. Two hundred twenty-nine college student volunteers completed the instruments under one of three conditions: I) Base Rate/Control; simulated Head Injured, but 2) without or 3) with prospect of financial gain for the injury. Although the simulated Head Injured groups did not differ significantly from one another, both groups endorsed more symptoms than the Base Rate group, suggesting that the instruments are vulnerable, to simulation. Base rates of head injury symptoms in the normal population, laypersons' knowledge about the sequelae of mild head injury, and implications of using symptom checklists in medicolegal evaluations were discussed, as was the desirability of replicating this study with noncollege student populations.

Journal Article↗
PubMed1993

Depressive mood states and their cognitive and personality correlates in college students: they improve over time.

About 30% of 171 college student respondents reported at least mild dysphoria. Depressed mood states were associated with dysfunctional attitudes and self-esteem problems, but not with gender or self-reported problem-solving ability. Findings about sex role orientation were mixed. The freshmen reported the highest levels of dysphoria, problem-solving difficulties, and dysfunctional attitudes, but there appeared to be consistent, gradual improvements, such that by the senior year students reported significantly less dysphoria. However, a 2-month follow-up found no significant changes in these areas, which suggests that the observed improvements may occur more gradually or may be an artifact of selective attrition from college. Implications of the results and directions for future research were discussed.

Adolescent↗