Ka-Hing Wong

Nutritional evaluation of some subtropical red and green seaweeds: Part I — proximate composition, amino acid profiles and some physico-chemical properties

Abstract The proximate composition, amino acid profile and some physico-chemical properties of two subtropical red seaweeds (Hypnea charoides and Hypnea japonica) and one green seaweed (Ulva lactuca) were investigated. The total dietary fiber [ranged from 50.3 to 55.4% dry weight (DW)] and ash (ranged from 21.3 to 22.8% DW) were the two most abundant components in these seaweeds but their crude lipid contents were very low (ranged from 1.42 to 1.64% DW). Although the crude protein content of the red seaweeds was significantly (p

Nutritional evaluation of some subtropical red and green seaweeds Part II. In vitro protein digestibility and amino acid profiles of protein concentrates

Abstract The nutritional values of seaweed protein concentrates (PCs) isolated from two red seaweeds (Hypnea charoides and Hypnea japonica) and one green seaweed (Ulva lactuca) were evaluated by determining their in vitro protein digestibility and amino acid profiles. Both protein extractability and in vitro protein digestibility of the red seaweed PCs (88.7–88.9%) were significantly (P

SARS-related Virus Predating SARS Outbreak, Hong Kong

Using immunofluorescence and neutralization assays, we detected antibodies to human severe acute respiratory syndrome–associated coronavirus (SARS-CoV) and/or animal SARS-CoV–like virus in 17 (1.8%) of 938 adults recruited in 2001. This finding suggests that a small proportion of healthy persons in Hong Kong had been exposed to SARS-related viruses at least 2 years before the recent SARS outbreak.

Surface decoration of selenium nanoparticles by mushroom polysaccharides–protein complexes to achieve enhanced cellular uptake and antiproliferative activity

By using mushroom polysaccharides–protein complexes (PSP) as the capping agent, size controllable and highly stable selenium nanoparticles (SeNPs) have been successfully created in a simple redox system of sodium selenite and ascorbic acid. SeNPs were capped with PSP through strong physical adsorption of hydroxyl groups of polysaccharides and imino groups of proteins on the surface of SeNPs. PSP surface decoration significantly enhanced the cellular uptake of SeNPs through endocytosis. Treatment with PSP–SeNPs significantly inhibited the growth of MCF-7 human breast cacinoma cells through induction of apoptosis with the involvement of PARP cleavage and caspase activation. Moreover, PSP–SeNPs not only significantly induced dose-dependent disruption of mitochondrial membrane potential in MCF-7 cells after 24 h treatment, but it also enhanced reactive oxygen species (ROS) generation as early as 15 min, indicating that ROS-mediated mitochondrial dysfunction may play an important role in PSP–SeNPs-induced apoptosis. Our results suggest that PSP–SeNPs may be a candidate for further evaluation as a chemopreventive agent for human cancers, and the strategy to use PSP as a surface decorator could be a highly efficient way to enhance the cellular uptake and anticancer efficacy of nanomaterials.

Changes in lipid profiles of rats fed with seaweed-based diets

Abstract The changes in lipid profiles of hypercholesterolemic rats fed with diets containing four Hong Kong seaweeds, Ulva sp., Hypnea charoides, Colpomenia sinuosa and Sargassum hemiphyllum , were evaluated. The cholesterol lowering potentials of the seaweeds were determined by comparing the levels of serum total cholesterol (TC), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride (TG) and hepatic cholesterol (HC) in the seaweed-based diet groups with those of the control group. All four seaweed-based diet groups showed similar trend of increase in HDL and triglyceride levels when compared to the control group. Although Hypnea charoides and Ulva sp. diet groups reduced the serum TC level (16% and 13.9%, respectively), these values exhibited no significant differences from those of the control. In addition, there were no significant differences of LDL level between control and H. charoides diet. However, H. charoides diet was the only seaweed diet that caused a depression of LDL level (10.7%). It seemed that H. charoides had a comparatively greater hypocholesterolemic potential than the others. Besides, all four seaweeds had no adverse effect on the growth of animals with respect to their body weight and the weights of internal organs except the C. sinuosa diet which caused a significant ( P

Induction of apoptosis and cell cycle arrest in A549 human lung adenocarcinoma cells by surface-capping selenium nanoparticles: an effect enhanced by polysaccharide-protein complexes from Polyporus rhinocerus.

Surface-capping agents play key roles in cellular uptake and biological activity of functional nanomaterials. In the present study, functionalized selenium nanoparticles (SeNPs) have been successfully synthesized using Polyporus rhinocerus water-soluble polysaccharide-protein complexes (PRW) as the capping agent during the reduction of selenium salts. The acquired monodisperse, spherical PRW-SeNPs presented desirable size distribution and stability in the solution. Moreover, PRW surface decoration significantly enhanced the cellular uptake of SeNPs via endocytosis. Exposure to PRW-SeNPs significantly inhibited the growth of A549 cells through induction of apoptosis and G2/M phase arrest (IC50 = 4.06 ± 0.25 μM) supported by an increase of sub-G1 and G2/M phase cell populations, DNA fragmentation, and chromatin condensation. Caspase-3/8 activation induced by PRW-SeNPs indicated that the activation of death receptors was the main cause of PRW-SeNP-induced apoptosis. Collectively, the results suggest that it is highly efficient to use PRW as a surface decorator of SeNPs to enhance cellular uptake and anticancer efficacy, and the PRW-SeNPs are potential chemopreventive agents for lung cancer therapy.

Delayed Progression to Death and to AIDS in a Hong Kong Cohort of Patients with Advanced HIV Type 1 Disease During the Era of Highly Active Antiretroviral Therapy

BACKGROUND The magnitude of the impact of highly active antiretroviral therapy (HAART) since its introduction in non-Western countries is not entirely clear. We studied disease progression among adult patients with advanced human immunodeficiency virus type 1 (HIV-1) infection in the pre-HAART (i.e., 1996 and earlier) and HAART eras in Hong Kong. METHODS The cohort of patients seen at the Integrated Treatment Center (Hong Kong) from 1984 through mid-2003 was retrospectively examined with respect to 3 clinical end points: death after the diagnosis of acquired immunodeficiency syndrome (AIDS), progression to AIDS after achieving a CD4 cell count of <200 cells/microL, and death after achieving a CD4 cell count of <200 cells/microL. RESULTS A total of 581 patients with advanced HIV-1 disease had AIDS and/or a CD4 cell count of <200 cells/microL. The incidences of death after AIDS (52.3% vs. 13.6%), AIDS progression after a CD4 cell count of <200 cells/microL (47.7% vs. 20.9%), and death after a CD4 cell count of <200 cells/microL (38.8% vs. 7.0%) were significantly higher among patients in the pre-HAART era than among those in the HAART era (P<.001 for all). On the basis of life-table analysis, the probabilities of death after AIDS (P<.0001), AIDS after a CD4 cell count of <200 cells/microL (P=.0063), and death after a CD4 cell count of <200 cells/microL (P<.0001) diminished in the HAART era, compared with the pre-HAART era. Median survival after AIDS increased from 29.8 months during the pre-HAART era to >70 months during the HAART era (P<.001). Compared with patients in the pre-HAART era, adjusted hazard ratios of clinical events were 0.15 (95% confidence interval [CI], 0.08-0.26) for death after AIDS, 0.38 (95% CI, 0.24-0.60) for AIDS after a CD4 cell count of <200 cells/microL, and 0.25 (95% CI, 0.15-0.40) for death after a CD4 cell count of <200 cells/microL for patients in the HAART era. CONCLUSIONS. The clinical outcome of patients with advanced HIV-1 disease in Hong Kong significantly improved during the HAART era. Our findings of extended durations of survival and AIDS-free status may be relevant to the expected health impacts associated with increased access to HAART in non-Western countries.

Influence of drying treatment on three Sargassum species 2. Protein extractability, in vitro protein digestibility and amino acid profile of protein concentrates

The effects of different drying treatments (oven- andfreeze-drying) on protein extractability of three subtropical brownseaweeds, Sargassum hemiphyllum, S. henslowianum and S. patens, as well as in vitro protein digestibility and amino acid profileof their protein concentrates (PCs) were investigated. When comparedwith freeze-drying, oven-drying not only improved significantly (p <0.05, two-way ANOVA, Tukey-HSD) the protein extractability of thethree Sargassum species but also the protein quality (in vitroprotein digestibility) of their PCs. Therefore, oven-drying was found to bemore suitable for protein extraction of brown seaweeds. The relationshipsbetween the protein extractability and total phenolic content in seaweedsand between in vitro protein digestibility and total phenolic contentin PCs were also discussed.

Influence of drying treatment on three Sargassum species

The effects were investigated of two different drying treatments (oven- andfreeze-drying) on the proximate composition, amino acid profile and somephysico-chemical properties of three subtropical brown seaweeds, Sargassum hemiphyllum, S. henslowianum and S. patens. Therewere significant differences (p < 0.05, two-way ANOVA,Tukey-HSD) in the ash, crude lipid and moisture contents of the threespecies treated by the two drying methods. The amount of total aminoacids in the oven-dried seaweed samples was significantly (p <0.05, two-way ANOVA, Tukey-HSD) lower than that of the freeze-driedones. However, there were no significant differences on the amount oftotal essential amino acids and individual amino acid between the oven- andfreeze-dried brown seaweeds. Physico-chemical properties includingswelling, water holding and oil holding capacity of the freeze-dried Sargassum species were significantly (p < 0.05, two-wayANOVA, Tukey-HSD) higher than those of the oven-dried seaweedsamples. This indicated that freeze-dried seaweeds had greater potential tobe used as food ingredients in formulated food products than oven-driedones.

Temporal Trend and Factors Associated with Late HIV Diagnosis in Hong Kong, a Low HIV Prevalence Locality

We studied the temporal trend of late HIV diagnosis and its determinants in Hong Kong. Three surrogate markers were used to proxy late diagnosis: AIDS within 3 months of HIV diagnosis, CD4 < 200/microL at HIV, and diagnosis at hospital. From 1984 to 2000, 1530 nonperinatal HIV infections and 495 patients with AIDS were reported. Overall, 23.9% to 52.1% of the patients were late presenters according to the three surrogates. There was no improvement in late diagnosis in the highly active antiretroviral therapy (HAART) era (1997-2000) compared to the pre-HAART era (1984-1996). Gender, ethnicity, age, and HIV exposure category were significant factors of late diagnosis on univariate analysis. On multivariate analysis, a lower risk of late diagnosis per all 3 surrogates was observed in men having sex with men (ranges of adjusted odds ratio [OR] [95% confidence interval [CI], 0.32-0.67 [0.21-0.91]) whereas the reverse was found for patients 35 years of age or older (ranges of adjusted ORs [95% CI], 1.62-2.80 [1.30-3.60]). In addition, male gender and Chinese ethnicity were associated with higher chance of having CD4 < 200/microL at HIV. The persistent trend of late HIV diagnosis in Hong Kong deserves attention. Strategies targeting infected people to enhance early HIV testing are needed, especially for those with risk factors of late diagnosis.