Chemical structure and chain conformation of the water-insoluble glucan isolated from Pleurotus tuber-regium

A water-insoluble polysaccharide (TM8) was isolated from sclerotium of Pleurotus tuber-regium by extraction with 0.5M NaOH aqueous solutions at 120 degrees C. Its chemical structure was confirmed by infrared, high performance liquid chromatography, gas chromatography, and (13)C NMR in dimethylsulfoxide (DMSO) to be composed of beta-(1 --> 3)-D-glucan backbone chain linked with a branched glucose, one out of every three glycosyl units being substituted at C6 position. The glucan TM8 in DMSO was fractionated by nonsolvent addition method into ten fractions, and the solution properties were studied by size exclusion chromatography combined with multiangle laser light scattering (SEC-MALLS) and viscometry in DMSO at 30 degrees C. The dependencies of intrinsic viscosity [eta] and radius of gyration [(s(2)(1/2)(z-2)] on weight-average molecular mass M(w) for this glucan were found to be [eta] = (9.24 +/- 0.2) x 10(-2)M(w)(0.51 +/- 0.02) (cm(3)g(-1)) and [(s(2)(1/2)(z-2)] = (3.67 +/- 0.3) x 10(-2)M(w)(0.56 +/- 0.02) (nm) in the range of M(w) from 1.07 x 10(4) to 77.4 x 10(4). Based on current theories for a wormlike chain, the conformational parameters of the glucan TM8 were found to be 408 (nm(-1)) for M(L), 3.1 (nm) for q, and 16.8 for C(infinity), suggesting that the polysaccharide exists as a dense random-coil chain in DMSO, due to branched structure.

Evaluation of mushroom dietary fiber (nonstarch polysaccharides) from sclerotia of Pleurotus tuber-regium (Fries) singer as a potential antitumor agent

Mushroom dietary fiber or nonstarch polysaccharides (NSPs) that were soluble in hot alkali and belonged to the beta-glucan type were isolated from the sclerotia of an edible mushroom, Pleurotus tuber-regium. The mushroom NSPs were further separated into a number of fractions [hot alkali extracts (HAEs)] with weight-average molecular weights (M(w)) ranging from 1 x 10(4) to 42.2 x 10(4). The HAE fractions [with M(w) of (5.8-17.1) x 10(4)] administered intraperitoneally at a dose of 20 mg/kg of body weight to BALB/c mice implanted with solid tumor Sarcoma 180 were found to be effective in inhibiting tumor proliferation with an inhibition ratio of > or =50%. In vitro experiments using human tumor cell lines HL-60 and HepG2 had shown that HAE fractions with M(w) of (5.8-42.2) x 10(4) also had antiproliferative activity at three different concentrations (50, 100, and 200 microg/mL) toward the tumor cell lines tested. All HAE fractions did not inhibit the growth of a normal kidney cell line (Vero) from monkey. It is therefore postulated that the antitumoral effect of NSPs from the sclerotia of P. tuber-regium is probably host-mediated and cytocidal.

Characterization of a novel phosphatidylinositol 3-phosphate-binding protein containing two FYVE fingers in tandem that is targeted to the Golgi

We have identified a novel protein of predicted molecular mass 40 kDa that contains two FYVE domains in tandem and has therefore been named TAFF1 (TAndem FYVE Fingers-1). The protein is expressed predominantly in heart and binds to PtdIns3P specifically, even though the FYVE domains in TAFF1 lacks the first Arg of the consensus sequence R(K/R)HHCR, critical for the PtdIns3P binding of other FYVE domains identified so far. The first Arg is replaced by a Thr and Ser in the N-terminal and C-terminal FYVE domains of TAFF1 respectively. Mutational analysis indicates that both FYVE domains are required for high affinity binding to PtdIns3P. Cell localization studies using a green fluorescent protein fusion show that TAFF1 is localized to the Golgi, and that the Golgi targeting sequence is located within the N-terminal 187 residues and not in either FYVE domain.

Special postpartum dietary practices of Hong Kong Chinese women

OBJECTIVE

A 'ginger vinegar soup' and other special dietary practices have been traditionally recommended for postpartum Chinese women. This paper describes these practices in the first 6 weeks postpartum, and details of the calcium and iron content of the 'ginger vinegar soup'.

DESIGN AND SUBJECTS

Results of this paper were generated from a longitudinal study on the nutritional status of Hong Kong Chinese postpartum women. 'Ginger vinegar soup' samples were collected at the 2 week home visits. Calcium and iron content were measured by the combination of dry ashing method and atomic absorption spectrophotometry. Results were compared with other types of soup and food sources. A food frequency questionnaire was completed at the 6 week interview to assess the special dietary practices during this period.

RESULTS

Fifty-one subjects completed the food frequency questionnaires. Twenty-two ginger vinegar soup samples and six other soup samples were collected. Consumption of special food items such as ginger, pig's trotters, egg and chicken varied greatly among subjects. More poultry and similar amounts of egg were consumed by our subjects as compared with the Hong Kong general population. Chicken soup and ginger vinegar soup were commonly consumed. Median calcium and iron contents of the ginger vinegar soup were 4.65 and 0.84 mg/dl, respectively. This calcium content was higher than that of the other six soup samples, but was low as compared with other calcium-rich foods. Iron content of ginger vinegar soup was higher than that of the other six samples and was comparable to some iron-rich foods.

CONCLUSIONS

Hong Kong Chinese postpartum women followed traditional dietary practices to different degrees. These practices were characterized by an increased poultry consumption. Iron content of ginger vinegar soup was comparable to some iron-rich foods.

Involved-field radiotherapy alone for early-stage non-small-cell lung cancer

PURPOSE

To describe the outcome of involved-field radiotherapy in patients with early-stage non-small-cell lung cancer (NSCLC).

METHODS AND MATERIALS

A written policy for the radical treatment of early-stage NSCLC with involved-field radiotherapy was adopted at our center in 1986. The sites of known disease were treated to a dose of 52.5 Gy in 20 daily fractions over 4 weeks without elective irradiation of radiologically uninvolved regional nodes. We have reviewed the outcome of this policy in 102 patients treated with radiotherapy alone between 1986 and 1995.

RESULTS

The patients' median age was 71.5 years. The stage distribution was as follows: T1, 33.3%; T2, 56.9%; T3, 8.8%; and T4, 1.0%. Only 5 cases were N1; the remainder were N0. Most patients (76.5%) were not surgical candidates because of co-morbidity. Ninety-three percent had a CT of the thorax as part of their initial staging, while mediastinoscopy was performed in only 16.7%. Overall survival was 35% at 3 years and 16% at 5 years. Recurrence free survival was 23.9% at 3 years and 13. 9% at 5 years. Cause-specific survival was 43.5% at 3 years and 26. 8% at 5 years. Of those who recurred, 68.9% had a local component of failure at initial relapse, and 49.2% failed locally without evidence of regional or distant metastases. Isolated regional nodal relapse at initial failure occurred in only 6.6% of recurrences. There were no treatment interruptions due to acute toxicity and no treatment-related deaths.

CONCLUSION

Involved-field radiotherapy alone cures a small but significant number of patients with early-stage NSCLC. This approach is recommended in patients who are unfit for surgery and who have severely compromised pulmonary function that would preclude the use of wide-field radiotherapy. The dose used in this study was well tolerated, but produced suboptimal local control rates.

Fractionation and characterization of mushroom dietary fiber (nonstarch polysaccharides) as potential nutraceuticals from sclerotia of Pleurotus tuber-regium (Fries) singer

The nonstarch polysaccharides (NSPs) in the total dietary fiber (TDF) from the sclerotia of Pleurotus tuber-regium (tiger milk mushroom) were fractionated by the sequential use of chemical solvents. About half of the TDF was solubilized and two major alkali-soluble fractions (1 and 4 N sodium hydroxide) that contained 126 and 293 g/kg TDF were obtained. Sugar analysis and infrared spectroscopy indicated that the NSPs in these alkali-soluble fractions were mainly beta-glucans and chitin. These alkali-soluble NSPs were further purified by anion-exchange chromatography followed by gel permeation chromatographic separation. Methylation analysis revealed that these purified glucans were highly branched and contained a mixture of sugar linkages of beta-1,3, beta-1,6, and beta-1,4. The potential use of these sclerotial beta-glucans as nutraceuticals was discussed.

A 3-phosphoinositide-dependent protein kinase-1 (PDK1) docking site is required for the phosphorylation of protein kinase Czeta (PKCzeta ) and PKC-related kinase 2 by PDK1

Members of the AGC subfamily of protein kinases including protein kinase B, p70 S6 kinase, and protein kinase C (PKC) isoforms are activated and/or stabilized by phosphorylation of two residues, one that resides in the T-loop of the kinase domain and the other that is located C-terminal to the kinase domain in a region known as the hydrophobic motif. Atypical PKC isoforms, such as PKCzeta, and the PKC-related kinases, like PRK2, are also activated by phosphorylation of their T-loop site but, instead of possessing a phosphorylatable Ser/Thr in their hydrophobic motif, contain an acidic residue. The 3-phosphoinositide-dependent protein kinase (PDK1) activates many members of the AGC subfamily of kinases in vitro, including PKCzeta and PRK2 by phosphorylating the T-loop residue. In the present study we demonstrate that the hydrophobic motifs of PKCzeta and PKCiota, as well as PRK1 and PRK2, interact with the kinase domain of PDK1. Mutation of the conserved residues of the hydrophobic motif of full-length PKCzeta, full-length PRK2, or PRK2 lacking its N-terminal regulatory domain abolishes or significantly reduces the ability of these kinases to interact with PDK1 and to become phosphorylated at their T-loop sites in vivo. Furthermore, overexpression of the hydrophobic motif of PRK2 in cells prevents the T-loop phosphorylation and thus inhibits the activation of PRK2 and PKCzeta. These findings indicate that the hydrophobic motif of PRK2 and PKCzeta acts as a "docking site" enabling the recruitment of PDK1 to these substrates. This is essential for their phosphorylation by PDK1 in cells.

Characterization of AMP-activated protein kinase gamma-subunit isoforms and their role in AMP binding

The AMP-activated protein kinase (AMPK) cascade plays an important role in the regulation of energy homeostasis within the cell. AMPK is a heterotrimer composed of a catalytic subunit (alpha) and two regulatory subunits (beta and gamma). We have isolated and characterized two isoforms of the gamma subunit, termed gamma2 and gamma3. Both gamma2 (569 amino acids) and gamma3 (492 amino acids) have a long N-terminal domain which is not present in the previously characterized isoform, gamma1. As with gamma1, mRNA encoding gamma2 is widely expressed in human tissues, whereas significant expression of gamma3 mRNA was only detected in skeletal muscle. Using isoform-specific antibodies, we determined the AMPK activity associated with the different gamma isoforms in a number of rat tissues. In most tissues examined more than 80% of total AMPK activity was associated with the gamma1 isoform, with the remaining activity being accounted for mainly by the gamma2 isoform. Exceptions to this were testis and, more notably, brain where all three isoforms contributed approximately equally to activity. There was no evidence for any selective association between the alpha1 and alpha2isoforms and the various gamma isoforms. However, the AMP-dependence of the kinase complex is markedly affected by the identity of the gamma isoform present, with gamma2-containing complexes having the greatest AMP-dependence, gamma3 the lowest, and gamma1 having an intermediate effect. Labelling studies, using the reactive AMP analogue 8-azido-[(32)P]AMP, indicate that the gamma subunit may participate directly in the binding of AMP within the complex.

Parental, peer, and teacher influences on the social behavior of Hong Kong Chinese adolescents

Intensive interviews and self-report questionnaires were used to investigate parental, peer, and teacher influences on the prosocial and antisocial behaviors of Hong Kong Chinese adolescents. Students came from 5 academically different high schools. Results indicated that perceived parental influence was positively associated with frequency of prosocial behavior and negatively associated with frequency of delinquent behavior. Students with good relationships with their parents and peers showed lower frequencies of antisocial behaviors than did students with bad relationships. Adolescents in different identity statuses (achievement, moratorium, foreclosure, diffusion; E. H. Erikson, 1968) showed different patterns of prosocial and antisocial behaviors. For example, adolescents in the identity achievement group exhibited high frequencies of prosocial behaviors and low frequencies of antisocial behaviors, but those in the identity moratorium group exhibited quite high frequencies of both prosocial and antisocial behaviors.

Epidemiology of diabetes mellitus in children in Hong Kong: the Hong Kong childhood diabetes register

OBJECTIVES

To establish a registry for Chinese children with onset of type 1 (insulin dependent) diabetes mellitus before 15 years of age and to determine the incidence of childhood onset type 1 diabetes mellitus in Chinese children in Hong Kong.

RESEARCH DESIGN AND METHODS

A registry was established in 1997 to collect childhood diabetes cases retrospectively from all districts in Hong Kong. The study included all newly diagnosed cases of diabetes with onset < 15 yr of age from 1st January 1984 to 31 December 1996. Primary ascertainment was based on review of medical records at all regional public hospitals in Hong Kong and survey of all the registered practitioners in Hong Kong. The secondary source of validation was made impractical, if not impossible, because of the recent implementation of the Personal Data Privacy Ordinance in Hong Kong.

RESULTS

A total of 255 diabetic cases were identified, 227 type 1 diabetes mellitus (218 were Chinese), 18 type 2 diabetes mellitus and 11 secondary diabetes. 246 patients were Chinese and 9 non-Chinese. The age-standardized incidence of type 1 and type 2 diabetes mellitus in southern Chinese children in Hong Kong was 1.4/100,000/yr and 0.1/100,000/yr respectively for children < 15 yr of age during the study period. The incidence rates for type 1 diabetes were 0.9, 1.5 and 1.7 per 100,000/yr for 0-4 years, 5 to 9 years and 10 to 14 years age-groups respectively. The incidence for males was 1.2/100,000/yr and for females 1.7/100,000/yr. A significant increase in the incidence was demonstrated during the study period by simple linear regression (slope 0.14/100,000/year, r2 = 0.73, p = 0.0002)

CONCLUSIONS

A diabetic registry is established in Hong Kong. This study documents a very low incidence rate of childhood type 1 diabetes mellitus in southern Chinese children in Hong Kong and we have seen an increasing incidence of the disease in the past 13 years.

Identification of a pocket in the PDK1 kinase domain that interacts with PIF and the C-terminal residues of PKA

The 3-phosphoinositide-dependent protein kinase-1 (PDK1) phosphorylates and activates a number of protein kinases of the AGC subfamily. The kinase domain of PDK1 interacts with a region of protein kinase C-related kinase-2 (PRK2), termed the PDK1-interacting fragment (PIF), through a hydrophobic motif. Here we identify a hydrophobic pocket in the small lobe of the PDK1 kinase domain, separate from the ATP- and substrate-binding sites, that interacts with PIF. Mutation of residues predicted to form part of this hydrophobic pocket either abolished or significantly diminished the affinity of PDK1 for PIF. PIF increased the rate at which PDK1 phosphorylated a synthetic dodecapeptide (T308tide), corresponding to the sequences surrounding the PDK1 phosphorylation site of PKB. This peptide is a poor substrate for PDK1, but a peptide comprising T308tide fused to the PDK1-binding motif of PIF was a vastly superior substrate for PDK1. Our results suggest that the PIF-binding pocket on the kinase domain of PDK1 acts as a 'docking site', enabling it to interact with and enhance the phosphorylation of its substrates.

Plasma and hepatic cholesterol levels and fecal neutral sterol excretion are altered in hamsters fed straw mushroom diets

The effect of the fruiting body and mycelium of Volvariella volvacea (straw mushroom) on the concentrations of plasma lipids, liver cholesterol, fecal neutral sterol and bile acid excretions was investigated in male Golden Syrian hamsters. The hamsters were fed a purified hypercholesterolemic diet (0.1% cholesterol, 10% fat) for 4 wk to elevate plasma lipid concentrations. Twelve hamsters with elevated plasma total cholesterol were randomly assigned to each treatment group: control (5% cellulose), mushroom fruiting body (5%) and mushroom mycelium (5%). After 4 wk of mushroom diet consumption, the plasma total cholesterol, HDL cholesterol, and combined VLDL + LDL cholesterol concentrations (mmol/L) were significantly lower than control in the group fed the fruiting body-diet (40, 38 and 43%, respectively) (P < 0.05). The liver cholesterol levels were significantly lower in both the mushroom fruiting body- and the mycelium-fed groups (28 and 21% in terms of concentration; 39 and 30% in terms of total content, respectively) (P < 0.05) than that in the control group. Fecal neutral sterol excretion in the mushroom fruiting body- and mycelium-fed groups was significantly higher (81 and 74%, respectively) (P < 0.05) than that in the control group. Although no significant differences (P > 0.05) in the excretion of fecal bile acids were observed among groups fed the mushroom diets and the control diet, the mushroom fruiting body diet-fed hamsters apparently had less bacterial degradation of cholic acid as indicated by a significantly greater proportion (P < 0.05) of fecal cholic acid than in controls. They also had a significantly lower proportion of fecal deoxycholic acid (P < 0.05). This study suggests that the fruiting body of the straw mushroom lowers elevated plasma cholesterol in hypercholesterolemic hamsters, whereas the mycelium does not.

Conceptions of success: their correlates with prosocial orientation and behaviour in Chinese adolescents

Data from a sample of 673 Chinese adolescents lent support to the hypothesis that conceptions of success or achievement goals affect both the inclination to and the actual performance of prosocial acts. With regard to attitude, it was found that: (a) task orientation (belief that success is gaining skill or understanding) and collaboration orientation (belief that success is working productively with one or more collaborators) increased with the inclination to help others, to co-operate and share things with others, to maintain an affective relationship with others, and to behave in compliance with social norms; and (b) ego orientation (belief that success is establishing one's competence as superior) was not generally associated with the inclination to perform prosocial acts. With regard to action, it was found that task orientation and collaboration orientation, but not ego orientation, increased with the number of normative and altruistic acts in the past year. The similarity between the belief-attitude correlation and the belief-action correlation indicates the robustness of the influence of conceptions of success. Also, sex differences and grade differences in the relationship between conceptions of success and prosocial and antisocial behaviours were found. Implications of the findings are discussed.

Changes in the Dietary Fiber (Resistant Starch and Nonstarch Polysaccharides) Content of Cooked Flours Prepared from Three Chinese Indigenous Legume Seeds

The effects of cooking on the dietary fiber (DF) content, which included resistant starch (RS) and nonstarch polysaccharides (NSP), of flours from Phaseolusangularis, Phaseolus calcaratus, and Dolichos lablab seeds, indigenous to China, were evaluated. The cooked legume flours were prepared by milling boiled and freeze-dried legume whole seeds. Total DF contents of all cooked flours were higher than those of the raw ones. The results showed an increase of NSP and RS to various extents with increasing cooking time of the flours. In the NSP of the legume flours, both the soluble and insoluble fractions increased during cooking, and a redistribution of the soluble and insoluble NSP components was observed. Generally, cooking increased the solubilization of the NSP in the legume seed flours, which might be important for their use as soup ingredients for therapeutic purposes. The increase of RS in the legume flours could be mainly due to the presence of cell-enclosed starch and retrograded starch formed during cooking. Such increase in the RS content of the cooked legume flours might have beneficial physiological effects for humans.

The relation of prosocial and antisocial behavior to personality and peer relationships of Hong Kong Chinese adolescents

The prosocial and antisocial behaviors of 2,862 Hong Kong Chinese adolescents were investigated. The major findings were as follows: (a) boys were more antisocial than girls: (b) negative peer influences were significantly stronger in boys than in girls, whereas positive peer influences were significantly stronger in girls than in boys; (c) antisocial adolescents tended to perceive their best friend as antisocial and exerting more negative influences on them, whereas prosocial adolescents tended to perceive their best friend as prosocial and exerting more positive influences on them; (d) antisocial behavior was positively associated with psychoticism and neuroticism; and (e) academic achievement tended to have a positive relation with prosocial behavior and a negative relation with antisocial behavior.

Characterization of AMP-activated protein kinase beta and gamma subunits. Assembly of the heterotrimeric complex in vitro

There is growing evidence that mammalian AMP-activated protein kinase (AMPK) plays a role in protecting cells from stresses that cause ATP depletion by switching off ATP-consuming biosynthetic pathways. The active form of AMPK from rat liver exists as a heterotrimeric complex and we have previously shown that the catalytic subunit is structurally and functionally related to the SNF1 protein kinase from Saccharomyces cerevisiae. Here we describe the isolation and characterization of the two other polypeptides, termed AMPKbeta and AMPKgamma, that together with the catalytic subunit (AMPKalpha) form the active kinase complex in mammalian liver. Sequence analysis of cDNA clones encoding these subunits reveals that they are related to yeast proteins that interact with SNF1, providing further evidence that the regulation and function of AMPK and SNF1 have been conserved throughout evolution. The amino acid sequence of the beta subunit is most closely related to SIP2 (35% identity), while the amino acid sequence of the gamma subunit is 35% identical with SNF4. We show that both AMPKbeta and AMPKgamma mRNA and protein are expressed widely in rat tissues. We show that AMPKbeta interacts with both AMPKalpha and AMPKgamma in vitro, whereas AMPKalpha does not interact with AMPKgamma under the same conditions. These results suggest that AMPKbeta mediates the association of the heterotrimeric AMPK complex in vitro, and will facilitate future studies aimed at investigating the regulation of AMPK in vivo.

Neonatal haemochromatosis associated with Down syndrome

METHODOLOGY

The clinical course of a child with neonatal haemochromatosis associated with Down syndrome is described, using case notes and post-mortem examination.

RESULTS

The patient died of liver failure on day 36. Post-mortem examination showed siderosis of liver, pancreas, heart, kidney and thyroid.

CONCLUSIONS

Neonatal haemochromatosis is a rare paediatric disease, the aetiology of which is unknown. Evidence suggests a disorder of fetoplacental iron handling with implications for recurrence in future pregnancies.

Development of the Multi-Trait Personality Inventory (MTPI): comparison among four Chinese populations

Anemic approach was adopted to develop a culture-specific instrument for the assessment of Chinese personality. The Multi-Trial Personality Inventory (MTPI) was administered to 1,673 men and 944 women in four major Chinese populations. It was found that Chinese in mainland China, Taiwan, Hong Kong, and the United States possess some common traits deeply rooted in the Chinese culture characterized by Confucian thoughts (e.g., self-discipline and moderation) and some additional traits nurtured by their respective environments. Consequently, findings of this study lent support to the hypothesis that, in spite of superficial discontinuities, there are basic continuities in the personality traits of mainland and overseas Chinese. The cross-cultural differences in personality were examined from a political-social perspective and also explained with a cultural-ecological model. In the development of the MTPI, a new methodology that relies on forming factor-consistent clusters was employed to deal successfully with the problem of complex factor space.