Search PubMed⌕ Search

Biomedical subjects

C Wong

Publications and source records attributed to C Wong.

354 records · Page 20Linked to original sources
PubMedDate not supplied

Identification of phosphatidate nonlamellar phases on liposomes by flow cytometry.

This study is the first report that demonstrates nonlamellar arrangements, or lipidic particles, of phosphatidate inserted in the lipid bilayer of liposomes using polyclonal antibodies from mice and flow cytometry. Sera immunoreactivity was analyzed using liposomes that displayed smooth bilayers of phosphatidate particles, as shown by electron microscopy. This cytofluorimetric analysis showed that immune mice sera have a specific immunoreactivity with the phosphatide particles formed by Mn2+, which also cross-reacted with those formed by Ca2+ and with cardiolipin particles formed by Mn2+. In addition, these immune sera hardly reacted with smooth bilayered liposomes, independently of the lipid composition studied. Thus, this new methodology can be applied to demonstrate nonlamellar molecular arrangements in biological membranes.

Animals↗
PubMedDate not supplied

Selection of human single chain Fv antibody fragments binding and inhibiting Helicobacter pylori urease.

Single chain Fv antibody fragments (scFv) binding to purified Helicobacter pylori urease were selected from a nonimmune human antibody repertoire displayed on filamentous phage. After three rounds of screening on solid phase urease, 44 clones were found to bind the enzyme and four distinct scFv were identified by sequencing their heavy and light chain variable region genes (V(H) and V(L)). Two of the selected human scFv (scFv B4 and scFv D9) inhibited the activity of H. pylori urease with inhibitory constants (K(i)) of 7 and 2 microM, respectively. Their affinity (K(d)) for H. pylori urease as determined by surface plasmon resonance ranged from 17 to 42 nM. Both scFv were able to bind to urease present on the surface of living H. pylori organisms as demonstrated by flow cytometry analysis. The binding sites of scFv B4 and D9 were mapped by the use of two random hexapeptide libraries (X6 and CX6C) displayed on filamentous bacteriophage. The selected peptide sequences were shown to inhibit scFv binding to H. pylori urease and thus could be used in a vaccination strategy as epitopes mimicking (mimotopes) the region of urease recognized by these human scFv antibody fragments.

Amino Acid Sequence↗
PubMedDate not supplied

Do heparin, hydrocortisone, and glyceryl trinitrate influence thrombophlebitis during full intravenous nutrition via a peripheral vein?

The aim of this prospective, randomized study was to determine if the addition of heparin and hydrocortisone, and the application of a topical glyceryl trinitrate patch over the catheter site (triple therapy) would results in a reduced incidence of thrombophlebitis during i.v. nutrition through a peripheral vein. Forty-six patients were randomized to receive either standard i.v. nutrition (i.v.N)(1200 mosm/kg) (control group, n = 23), or i.v.N plus triple therapy (study group, n = 23). The patient's arm was examined daily, and the catheter was removed if signs of thrombophlebitis were evident. The two groups were well matched in terms of age and gender, as well as indication for feeding and total days of i.v.N supplied. The catheters in the study group survived longer (p < .0001), and resulted in a lower incidence of thrombophlebitis (p < .05). The time of onset of thrombophlebitis was delayed in the study group (p < .0001). It is recommended that heparin, hydrocortisone, and a glyceryl trinitrate patch should be administered to all patients receiving i.v. nutrition via a fine-bore peripheral catheter.

Administration, Cutaneous↗
PubMedDate not supplied

Evaluation of an advanced health assessment course for acute care nurse practitioners.

The Acute Care Nurse Practitioner (ACNP) role is being implemented in many centres in Canada. Administrators need to be aware there are very few universities in Canada that prepare ACNPs for advanced health assessment. Therefore, a need may exist for continuing education in the work environment. The ACNPs in London, Ontario recognized such a need, and developed and implemented an Advanced Health Assessment Course using available resources, and administrators supported participation in the course. A pre-post course evaluation based on Bandura's Self-Efficacy theory (1997) was performed. From pre-test to post-test there were significant increases in: (a) the use of health assessement skills; (b) confidence in performing these skills; and (c) confidence in recognizing abnormalities on health assessment. The reasons most often cited for infrequent skill use were "inappropriate to clinical setting" and "used only if problem suspected". The majority of participants agreed that the course met their needs. Implications for practice include administrative support for continuing education at other centres to enhance health assessment skills of ACNPs.

Acute Disease↗
PubMedDate not supplied

Response of canine soft tissue sarcomas to radiation or radiation plus hyperthermia: a randomized phase II study.

Sixty-four dogs with spontaneous soft tissue sarcomas without evidence of metastases were stratified by tumour volume and randomized to receive graded doses of radiotherapy (XRT) alone or radiotherapy plus hyperthermia (HT). An improvement in duration of local control was achieved with the addition of hyperthermia as compared with XRT alone (Wilcoxon, p = 0.040; log rank, p = 0.064). Overall frequency of late complications was not different for the two treatment arms when comparing across equivalent XRT dose groups. Frequency of distant metastases after therapy completion was not significantly different for the two treatment arms at 1 year (7.4% for XRT versus 20% for HT plus XRT) or 2 years (11.5% for XRT versus 25% for HT plus XRT) post therapy. These results suggest that a therapeutic gain was achieved for this group of tumour-bearing animals. Uni- and multivariate analyses were performed to examine the potential for various factors to influence treatment outcome. Patient related variables included tumour stage, histologic subtype and grade and tumour site. Treatment related variables included total radiation dose and 15 descriptors of temperature distributions achieved during hyperthermia. When considering patient related factors, tumour histology, grade and location were important predictors of time to minimum volume, but only tumour location influenced time to tumour regrowth. When considering treatment related factors, radiation dose was not significantly correlated with time to minimum volume or time to local regrowth, but it was correlated with probability for late normal tissue damage in the XRT alone group (p = 0.005). For the hyperthermia treatments, 13 of 15 tumour temperature distribution descriptors were correlated with time to minimum volume, but none were correlated with time to local regrowth. These results suggest that caution should be used in interpreting the value of temperature distribution descriptors in predicting for long-term local control after hyperthermia and radiotherapy, based on analysis of short-term responses.

Animals↗
PubMedDate not supplied

L-myc genotypes in Hong Kong Chinese colorectal carcinoma patients.

L-myc genotypes have been correlated with prognosis in different human tumors. Its role in colorectal carcinoma (CRC) is still unclear. This study aimed to assess the L-myc genotypes in 99 Hong Kong Chinese CRC patients by PCR-RFLP techniques. The results obtained were correlated with clinical, histological and pathological parameters and genetic alterations. The observed frequency of L-myc genotypes (LL:LS:SS) was 27:46:26. The ratio of S to L alleles was 0.51:0.49. Distribution of L-myc genotypes and alleles in Hong Kong Chinese CRC was similar to that of healthy Chinese and CRC patients of other ethnic origins. The homozygous SS genotype was significantly associated with Dukes' stages C versus B. Other parameters including sex, differentiation status and survival, and genetic alterations such as p53 and Ki-ras mutations and Dcc LOH had no significant association with L-myc SS genotype.

Asian People↗
PubMedDate not supplied

Electron microscopy and biological properties of pBR322 DNA condensed with the trivalent cations spermidine and hexammine cobalt (III).

Electron microscopy and the biological properties of susceptibility to DNase I, genetic transcription, and transformation of pBR322 DNA compacted with spermidine or hexammine cobalt (III), were analyzed in order to characterize the association of DNA in its compacted form with these two different trivalent cations. Spermidine and hexammine cobalt (III) produced an average 4-fold reduction of the DNA perimeter in compact DNA forms, which were doughnut-shaped toroids and cylinders. Both compacted DNAs were resistant to the hydrolytic activity of DNase I. However, spermidine-condensed pBR322 DNA was 10-fold and 4 to 6-fold more active in transcription and transformation, respectively, than naked pBR322. I. Hexammine cobalt (III)-condensed pBR322 was inactive in both biological properties. An inhibitory effect of hexammine cobalt (III) on RNA polymerase and genetic transformation activities was discarded because at higher ionic strength, in which DNA is not compacted by hexammine cobalt (III), transcription and transformation were similar to those observed with naked DNA. This information showed that the interaction of hexammine cobalt (III) with the DNA converted the pBR322 DNA into an inert molecule. In contrast, pBR322 did not loose its biological properties after its interaction with the polyamine spermidine; i.e., experimental condensation of pBR322 DNA by spermidine produced compacted DNA that is more similar to compact native genomes than relaxed DNA. These experiments led us to conclude that spermidine-condensed DNA can be used to study the roll of the native supercoiling of DNA in the regulation of genetic replication and transcription, as well as to study the mechanisms that allow the accessibility of the supercoiled or condensed DNA substrate for enzymes.

Cations↗
PubMedDate not supplied

Selected soft tissue malignancies of the foot: an in-depth study with case reports.

Soft tissue malignancies represent a diagnostic and therapeutic challenge to the podiatric physician. In order to improve prognosis and increase survival rates of affected patients, prompt clinical and histologic recognition of suspect lesions is necessary. Here we present information and case reports on selected soft tissue malignancies including Kaposi's sarcoma, malignant melanoma, synovial sarcoma, and epithelioid sarcoma to aid the practitioner in recognizing these serious lesions that occur in the foot.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Stress-point intervention for parents of children hospitalized with chronic conditions.

Stress-point intervention by Nurses (SPIN) is a research-based intervention that can be used to assist families whose child has a chronic condition and is repeatedly hospitalized. The intervention addresses attendant family stressors, tasks, and concerns. SPIN incorporates parent-nurse contact before admission, during hospitalization, and after discharge. A nurse assists each family to develop their unique set of coping strategies, which are shaped by the family's own concerns and resources and the nurse's expertise. The effectiveness of SPIN has been tested in two intervention studies, one based in the community and another based in ambulatory clinics. Both studies found that families receiving SPIN interventions had better parental coping and family functioning, and there was less developmental regression in the child after hospitalization. SPIN can be used by nurses having experience working with families and children. A self-directed learning program assists with understanding of theoretical and practical aspects of SPIN.

Adaptation, Psychological↗