Effects of forest management practices on carbon dynamics of China's boreal forests under changing climates

Climate change and forest management practices influence forest productivity and carbon budgets, and understanding their interactions is necessary to develop accurate predictions of carbon dynamics as many countries in the world strive towards carbon neutrality. Here, we developed a model-coupling framework to simulate the carbon dynamics of boreal forests in China. The expected dynamics of forest recovery and change following intense timber harvesting in the recent past and projected carbon dynamics into the future under different climate change scenarios and forest management practices (e.g., restoration, afforestation, tending, and fuel management). We predict that under current management strategies, climate change would lead to increased fire frequency and intensity, eventually shifting these forests from carbon sinks towards being carbon sources. This study suggests that future boreal forest management should be altered to reduce the probability of fire occurrence and carbon losses caused by catastrophic fires through planting deciduous species, mechanical removal, and prescribed fire.

Repurposing of niclosamide as a STAT3 inhibitor to enhance the anticancer effect of chemotherapeutic drugs in treating colorectal cancer

AIMS

Colorectal cancer (CRC) is the third most common cancer worldwide. Mutation of various cell signaling molecules or aberrant activation of signaling pathways leads to poor response to chemotherapy in CRC. Signal transducer and activator of transcription protein 3 (STAT3) is an important signaling molecule, which plays crucial roles in regulating cell survival and growth. In this study, the potentitation of chemotherapy by putative STAT3 inhibitors for treating CRC was investigated.

MAIN METHODS

A few putative STAT3 inhibitors were investigated. Niclosamide, originally indicated for the treatment of tapeworm infection, was chosen for further investigation in five CRC cell lines (HCT116, HT29, HCC2998, LoVo and SW480). Western blot analysis was used to evaluate the expression of STAT3/phospho-STAT3 and its downstream targets. Sulforhodamine B assay was used to evaluate the cytotoxicity of drug combinations. Flow cytometric assays were used to investigate the apoptotic and cell cycle effect.

KEY FINDINGS

Niclosamide was found to inhibit expression and activation of STAT3 in a concentration- and time-dependent manner, thereby downregulating STAT3 downstream targets including survivin and cyclin-D1 to induce apoptosis and cell cycle arrest. When combined with niclosamide or specific STAT3 inhibitor (C188-9), the cytotoxicity and DNA damage response from SN38 (the active metabolite from irinotecan) were significantly enhanced. The sequential exposure of SN38 followed by niclosamide was found to be the most potent treatment sequence for the drug combination.

SIGNIFICANCE

Niclosamide represents a promising candidate for repurposing to potentiate the anticancer activity of chemotherapeutic drugs.

[The role of PACAP protein in chronic sinusitis with or without nasal polyps]

Objective:To investigate the expression of PACAP protein in chronic rhinosinusitis without/with nasal polyps and refractory chronic rhinosinusitis.Method: Fifty-three patients with nasal polyps,70 cases with chronic sinusitis, 28 patients with refractory chronic rhinosinusitis and 20 control cases were enrolled for this study. The expression of PACAP protein was detected by immunochemistry.Result: ①PACAP protein were expressed in nasal epithelium，glandular epithelium and goblet cells；②The positive intensity of PACAP was" +", " +++", "－-+",and " ++" in nasal polyps, chronic rhinosinusitis, refractory chronic rhinosinusitis, and control group, respectively.Conclusion:PACAP protein mainly locates in nasal epithelium，glandular epithelium and goblet cells. Reduced expression of PACAP may be related with onset of chronic rhiniosinusitis without/with nasal polyps.

One-step synthesis and luminescence properties of tetragonal double tungstates nanocrystals

A versatile one-step thermolysis protocol is demonstrated to produce a uniform dispersion of tetragonal double tungstates NaRE(WO4)2 (RE = rare earth) nanocrystals (NCs). Oriented attachment in the [001] direction occurred. Doping with luminescent RE(3+) ions resulted in highly luminescent NCs showing characteristic line emission of the dopant as well as a blue emission assigned to surface adsorbed organic species.

Metabolic profiles in the response to supplementation with composite antimicrobial peptides in piglets challenged with deoxynivalenol

Deoxynivalenol (DON) causes various toxic effects in human and animals. However, our previous studies have shown that composite antimicrobial peptides (CAP) can have a protective effect in piglets challenged with DON. This study was conducted to evaluate the effect of the CAP GLAM 180# on the metabolism of piglets challenged with DON using a nuclear magnetic resonance (NMR)-based metabolomics approach. A total of 28 individually housed piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned into 4 treatment groups (7 pigs/treatment) based on a 2 × 2 factorial arrangement that were fed, respectively, a basal diet (NC), basal diet + 0.4% CAP (basal + CAP), basal diet + 4 mg/kg DON (basal + DON), and basal diet + 4 mg/kg DON + 0.4% CAP (DON + CAP). A 7-d adaptation period was followed by 30 d of treatment. Blood samples were then collected for metabolite analysis by proton NMR (H-NMR) spectroscopy and liquid chromatography tandem mass spectrometry (LC-MS/MS). The combined results of H-NMR spectroscopy and LC-MS/MS showed that DON increased ( < 0.05) the serum concentrations of low-density lipoprotein, glycoprotein, urea, trimethylamine-N-oxide (TMAO), and lactate as well as those of almost all essential AA and some nonessential AA but decreased the concentrations of high-density lipoprotein (HDL), unsaturated lipids, citrate, choline, and fumarate compared with those in NC treatment ( < 0.05). There was a significant interaction effect ( < 0.05) of supplementation with DON and CAP on some metabolites showed that the serum concentrations of HDL, unsaturated lipids, Pro, citrate, and fumarate were greater ( < 0.05) whereas those of glycoprotein, urea, TMAO, Gly, and lactate were lower in the DON + CAP treatment compared with those in the basal + DON treatment ( < 0.05). These findings indicated that DON causes disturbances in AA, lipid, and energy metabolism and that CAP could partially attenuate the above metabolic disturbances induced by DON.

Oral administration of putrescine and proline during the suckling period improves epithelial restitution after early weaning in piglets

Polyamines are necessary for normal integrity and the restitution after injury of the gastrointestinal epithelium. The objective of this study was to investigate the effects of oral administration of putrescine and proline during the suckling period on epithelial restitution after early weaning in piglets. Eighteen neonatal piglets (Duroc × Landrace × Large Yorkshire) from 3 litters (6 piglets per litter) were assigned to 3 groups, representing oral administration with an equal volume of saline (control), putrescine (5 mg/kg BW), and proline (25 mg/kg BW) twice daily from d 1 to weaning at 14 d of age. Plasma and intestinal samples were obtained 3 d after weaning. The results showed that oral administration of putrescine or proline increased the final BW and ADG of piglets compared with the control (P < 0.05). Proline treatment decreased plasma D-lactate concentration but increased the villus height in the jejunum and ileum, as well as the percentage of proliferating cell nuclear antigen (PCNA) positive cells and alkaline phosphatase (AKP) activity in the jejunal mucosa (P < 0.05). The protein expressions for zonula occludens (ZO-1), occludin, and claudin-3 (P < 0.05) but not mRNA were increased in the jejunum of putrescine- and proline-treated piglets compared with those of control piglets. The voltage-gated K+ channel (Kv) 1.1 protein expression in the jejunum of piglets administrated with putrescine and the Kv1.5 mRNA and Kv1.1 protein levels in the ileum of piglets administrated with proline were greater than those in control piglets (P < 0.05). These findings indicate that polyamine or its precursor could improve mucosal proliferation, intestinal morphology, as well as tight junction and potassium channel protein expressions in early-weaned piglets, with implications for epithelial restitution and barrier function after stress injury.

Pyrrolidine dithiocarbamate restores gastric damages and suppressive autophagy induced by hydrogen peroxide

It is well known that gastric barrier is very important for protecting host from various insults. Simultaneously, autophagy serving as a prominent cytoprotective and survival pathway under oxidative stress conditions is being increasingly recognized. Thus, this study was conducted for investigating the effect of pyrrolidine dithiocarbamate (PDTC) on gastric barrier function and autophagy under oxidative stress induced by intragastric administration of hydrogen peroxide (H2O2). The gastric tight junction proteins [zonula occludens-1 (ZO1), occludin, and claudin1], autophagic proteins [microtubule-associated protein light chain 3I(LC3I), LC3II, and beclin1], and nuclear factor kappa B (NF-κB) signaling pathway (p65 and IκB kinase α/β) were determined by Western blot. The results showed that H2O2 exposure disturbed gastric barrier function with decreased expression of ZO1, occludin, and claudin1, and reduced gastric autophagy with decreased conversion of LC3I into LC3II in mice. However, treatment with PDTC restored these adverse effects evidenced by increased expression of ZO1 and claudin1 and increased conversion of LC3I into LC3II. Meanwhile, H2O2 exposure decreased normal human gastric epithelial mucosa cell line (GES-1) viability in a concentration-dependent way. However, after being exposed to H2O2, GES-1 exhibited autophagic response which was inconsistent with our in vivo results in mice, while PDTC failed to decrease autophagy in GES-1 induced by H2O2. Simultaneously, the beneficial effect of PDTC on gastric damage and autophagy in mice might be independent of inhibition of NF-κB. In conclusion, PDTC treatment restores gastric damages and reduced autophagy induced by H2O2. Therefore, PDTC may serve as a potential adjuvant therapy for gastric damages.

Highly stable sub-5 nm Sn₆O₄(OH)₄ nanocrystals with ultrahigh activity as advanced photocatalytic materials for photodegradation of methyl orange

Among numerous active photocatalytic materials, Sn-based oxide nanomaterials are promising photocatalytic materials in environmental protection measures such as water remediation due to their excellent physicochemical property. Research on photocatalytic nanomaterials for photodegradation of methyl orange (MO) so far has focused on TiO₂-based nanostructures; e.g., TiO₂-P25 is recognized to be the best commercial photocatalyst to date, rather than Sn-based oxide nanomaterials, in spite of their impressive acid- and alkali-resistant properties and high stability. Here, we demonstrate very high photocatalytic activity of highly stable sub-5 nm hydromarchite (Sn₆O₄(OH)₄) nanocrystals synthesized by a simple and environmentally friendly laser-based technique. These Sn₆O₄(OH)₄ nanocrystals exhibit ultrahigh photocatalytic performance for photodegradation of MO and their degradation efficiency is far superior to that of TiO₂-P25. The detailed investigations demonstrated that the great photocatalytic activity results from the ultrafine size and unique surface activity induced by the laser-based technique. Mass production of reactive species of hydroxyl radicals was detected in the experiments due to the appropriate bandgap of Sn₆O₄(OH)₄ nanocrystals. These findings actually open a door to applications of Sn-based oxide nanomaterials as advanced photocatalytic materials.

Changes in peripheral blood Th1 and Th2 cells in rat liver transplantation under different immune statuses

In this study, early expressions of peripheral blood Th1 and Th2 cells were documented following rat liver transplantation and related to immune status. Rats were divided into 3 groups: group A (control): syngeneic transplantation (Brown Norway (BN) → BN); group B: allogeneic transplantation + cyclosporine A (CsA); group C: allogeneic transplantation (Lewis → BN). Flow cytometry was used to analyze peripheral blood CD4(+)CD45RC percentage on days 1, 3, 5, 7, and 14 following transplantation, and were compared to graft rejection pathological grades and receptor survival times. The average survival of groups A and B exceeded 100 days, which was significantly longer than that of group C (3.56 ± 34.3 days). With the exception of the first day, rejection grades were significantly higher in groups C and B compared to group A, and group C rejection grades were significantly higher than those of group B. Three days after transplantation, the CD4(+)CD45RC(+) to CD4(+)CD45RC(-) ratio of group C was significantly higher than that of groups A and B. In group B, the CD4(+)CD45RC(+) to CD4(+)CD45RC(-) ratio was negatively correlated to the rejection grade (r = -0.565, P < 0.01), whereas this relationship was positive in group C (r = 0.745, P < 0.01). In conclusion, peripheral blood Th1 was highly expressed during rejection in rat liver grafts. Peripheral blood Th2 tended to increase early under rejection inhibition with CsA, and its high expression level may correlate with long-term acceptance or tolerance of transplanted livers.

Effects of composite antimicrobial peptides in weanling piglets challenged with deoxynivalenol: I. Growth performance, immune function, and antioxidation capacity

The mycotoxin deoxynivalenol (DON) is a food contaminant that leads to reduced feed intake and reduced BW gain, as well as organ impairment. On the other hand, antimicrobial peptides have been shown to have positive effects on growth performance, nutrient digestibility, and immune function. The purpose of this study was to investigate the protective effects of composite antimicrobial peptides (CAP) on piglets challenged with DON. After a 7-d adaptation period, 28 individually housed piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% CAP (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 ppm DON + 0.4% CAP (DON + CAP). On d 15 and 30 after the initiation of treatment, blood samples were collected for the determination of blood profile. Piglets were monitored for 30 d to assess performance and then were slaughtered to obtain organs for the determination of the relative weight of organs. The results showed that dietary supplementation with DON decreased (P < 0.05) ADFI, ADG, and G:F, whereas dietary supplementation with CAP improved ADG and G:F (P < 0.05). The relative weight of the kidney and pancreas was greater and the relative weight of the spleen was lighter in the DON treatment than in the other 3 treatments (P < 0.05). There were no effects (P > 0.05) on other relative weights of viscera, except the relative weight of the gallbladder, but the diamine oxidase activity in the liver decreased in DON-treated piglets (P < 0.05). Piglets in the DON treatment had increased serum concentrations of alkaline phosphatase, alanine transaminase, and aspartate aminotransferase and a dramatic decrease in total protein (P < 0.05), whereas there were no differences (P > 0.05) between the DON + CAP treatment and the other treatments. The DON treatment decreased the numbers of red blood cells and platelets, as well as the serum catalase concentrations, and decreased the serum concentrations of H2O2, maleic dialdehyde, and nitric oxide (P < 0.05). The numbers of platelets and thrombocytocrit, as well as the serum concentrations of catalase, were greater, whereas the maleic dialdehyde concentrations were decreased, in both the CAP and DON + CAP treatments compared with the other treatments (P < 0.05). Compared with the control treatment, DON decreased peripheral lymphocyte proliferation on d 15, whereas supplementation with CAP increased it on d 15 and 30 (P < 0.05). These findings indicate that CAP could improve feed efficiency, immune function, and antioxidation capacity and alleviate organ damage, and thus, it has a protective effect in piglets challenged with DON.

Effects of composite antimicrobial peptides in weanling piglets challenged with deoxynivalenol: II. Intestinal morphology and function

Deoxynivalenol (DON) affects animal and human health and targets the gastrointestinal tract. The objective of this study was to evaluate the ability of composite antimicrobial peptides (CAP) to repair intestinal injury in piglets challenged with DON. A total of 28 piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% composite antimicrobial peptide (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 mg/kg DON + 0.4% CAP (DON + CAP). After an adaptation period of 7 d, blood samples were collected on d 15 and 30 after the initiation of treatment for determinations of the concentrations of D-lactate and diamine oxidase. At the end of the study, all piglets were slaughtered to obtain small intestines for the determination of intestinal morphology, epithelial cell proliferation, and protein expression in the mammalian target of rapamycin (mTOR) signaling pathway. The results showed that DON increased serum concentrations of D-lactate and diamine oxidase, and these values in the CAP and DON + CAP treatments were less than those in the NC and DON treatments, respectively (P < 0.05). The villous height/crypt depth in the jejunum and ileum and the goblet cell number in the ileum in the CAP and DON + CAP treatments were greater than those in the NC and DON treatments (P < 0.05). The proliferating cell nuclear antigen (PCNA) labeling indexes for the jejunum and ileum in the DON + CAP treatment were greater than those in the DON treatment (P < 0.05). The DON decreased (P < 0.05) the relative protein expression of phosphorylated Akt (Protein Kinase B) and mTOR in the jejunal and ileal mucosa and of phosphorylated 4E-binding protein 1 (p-4EBP1) in the jejunal mucosa, whereas CAP increased (P < 0.05) the protein expression of p-4EBP1 in the jejunum. These findings showed that DON could enhance intestinal permeability, damage villi, cause epithelial cell apoptosis, and inhibit protein synthesis, whereas CAP improved intestinal morphology and promoted intestinal epithelial cell proliferation and protein synthesis, indicating that CAP may repair the intestinal injury induced by DON.

Resonant field emission through amorphous diamond thin films (a model study)

A model for field emission through an amorphous diamond thin film with defects is constructed. Theoretical study shows that the emission is enhanced by attractive defects which would make the resonant emission observable for films with thickness of about 10nm. The emitted current density in typical parameters is calculated as functions of thickness, field strength and defect density. The energy distribution of emitted electrons is attained.

Biosynthesis and secretion of pituitary hormones: dynamics and regulation

Production and secretion of hormones by the pituitary involve highly orchestrated intracellular transport and sorting steps. Hormone precursors are routed through a series of compartments before being packaged in secretory granules. These highly dynamic carriers play crucial roles in both prohormone processing and peptide exocytosis. We have employed the ACTH-secreting AtT-20 cell line to study the membrane sorting events that confer functionality (prohormone activation and regulated exocytosis) to these secretory carriers. The unique ability of granules to promote prohormone processing is attributed to their acidic interior. Using a novel avidin-targeted fluorescence ratio imaging technique, we have found that the trans-Golgi of live AtT-20 cells maintains a mildly acidic (approximately pH 6.2) interior. Budding of secretory granules causes the lumen to acidify to <pH 6.0, which is both necessary and sufficient to trigger SPC3-mediated proteolytic conversion of proopiomelanocortin to ACTH. Investigation of the pH regulatory mechanism indicates that the trans-Golgi and secretory granules maintain different pH values by distinct sorting of key membrane transporters. Mathematical modeling of our data suggests that the decreasing pH values of organelles of the regulated secretory pathway is established by gradually increasing the density of active H+ pumps from the ER to Golgi while concomitantly decreasing the H+ permeability from ER to Golgi to secretory granules. An in vitro assay was developed to study the formation of processing-competent secretory granules from their processing-incompetent precursor trans-Golgi compartment. Our data suggest that ARF1-mediated sorting of proton pumps and leaks during early stages of granule formation confers processing competency to the resulting organelle. Once formed, these young granules continue to undergo membrane remodeling which results in dynamic changes in their exocytotic behavior. Two SNAREs, VAMP4 and synaptotagmin IV, enter newly formed granules but are removed from the maturing granule membrane by vesicle budding. Sorting of these proteins is correlated with the acquisition of Ca2+-triggered exocytosis and a decrease in unregulated exocytotic rate. Thus, biosynthesis and secretion of pituitary hormones are dynamically regulated by intracellular sorting events that govern the functions of their secretory carriers.

Association of blood arsenic levels with increased reactive oxidants and decreased antioxidant capacity in a human population of northeastern Taiwan

Arsenic is a notorious environmental toxicant known as both a carcinogen and an atherogen in human beings, but the pathogenic mechanisms are not completely understood. In cell culture studies, trivalent arsenic enhanced oxidative stress in a variety of mammalian cells, and this association may be closely associated with the development of arsenic-related diseases. To investigate the effect of arsenic exposure on oxidative stress in humans, we conducted a population study to determine the relationships of blood arsenic to reactive oxidants and antioxidant capacity at the individual level. We recruited 64 study subjects ages 42-75 years from residents of the Lanyang Basin on the northeast coast of Taiwan, where arsenic content in well water varies from 0 to > or = 3,000 microg/L. We used a chemiluminescence method, with lucigenin as an amplifier for measuring superoxide, to measure the plasma level of reactive oxidants. We used the azino-diethyl-benzthiazoline sulphate method to determine the antioxidant capacity level in plasma of each study subject. We determined arsenic concentration in whole blood by hydride formation with an atomic absorption spectrophotometer. The average arsenic concentration in whole blood of study subjects was 9.60 +/- 9.96 microg/L (+/- SD) with a range from 0 to 46.50 microg/L. The level of arsenic concentration in whole blood of study subjects showed a positive association with the level of reactive oxidants in plasma (r = +0.41, p = 0.001) and an inverse relationship with the level of plasma antioxidant capacity (r = -0.30, p = 0.014). However, we found no significant association (p = 0.266) between levels of plasma reactive oxidants and antioxidant capacity. Our results also show that the lower the primary arsenic methylation capability, the lower the level of plasma antioxidant capacity (p = 0.029). These results suggest that ingestion of arsenic-contaminated well water may cause deleterious effects by increasing the level of reactive oxidants and decreasing the level of antioxidant capacity in plasma of individuals. Persistent oxidative stress in peripheral blood may be a mechanism underlying the carcinogenesis and atherosclerosis induced by long-term arsenic exposure.

Mechanisms of pH regulation in the regulated secretory pathway

A precise pH gradient between organelles of the regulated secretory pathway is required for sorting and processing of prohormones. We studied pH regulation in live endocrine cells by targeting biotin-based pH indicators to cellular organelles expressing avidin-chimera proteins. In AtT-20 cells, we found that steady-state pH decreased from the endoplasmic reticulum (ER) (pH(ER) = 7.4 +/- 0.2, mean +/- S.D.) to Golgi (pH(G) = 6.2 +/- 0.4) to mature secretory granules (MSGs) (pH(MSG) = 5.5 +/- 0.4). Golgi and MSGs required active H(+) v-ATPases for acidification. ER, Golgi, and MSG steady-state pH values were also dependent upon the different H(+) leak rates across each membrane. However, neither steady-state pH(MSG) nor rates of passive H(+) leak were affected by Cl(-)-free solutions or valinomycin, indicating that MSG membrane potential was small and not a determinant of pH(MSG). Therefore, our data do not support earlier suggestions that organelle acidification is primarily regulated by Cl(-) conductances. Measurements of H(+) leak rates, buffer capacities, and estimates of surface areas and volumes of these organelles were applied to a mathematical model to determine the H(+) permeability (P(H+)) of each organelle membrane. We found that P(H+) decreased progressively from ER to Golgi to MSGs, and proper acidification of Golgi and MSGs required gradual decreases in P(H+) and successive increases in the active H(+) pump density.

A rapid method for evaluating microbicidal activity of dentifrice formulations against salivary bacteria ex vivo

A new rapid ex vivo method was developed for evaluating the short-term bactericidal activity of dentifrices against salivary microorganisms. Dentifrice aliquots of 0.25 or 1.0 g were rapidly dispersed into 3.5 mL of freshly pooled human saliva, and 1.0 mL aliquots of the dentifrice-saliva suspension were collected after 30 or 60 seconds of exposure, diluted in neutralizing broth and plated on non-selective agar media for enumeration of surviving total cultivable microflora. Eight experimental dentifrices containing increasing amounts (0 to 2.6%) of a fixed ratio of essential oils (thymol, menthol, methyl salicylate and eucalyptol) were dispersed in saliva at a 0.25:3.5 (w/v) dentifrice:saliva ratio. Recoverable CFUs/mL at 30 sec. were reduced in a dose-responsive manner from > 10(6) to < 10(4). Additional tests using both 0.25 and 1.0 g amounts of dentifrice prototypes containing 2.1% of the essential oil mixture showed that the experimental dentifrices exhibited highly significant (approximately 2.5 log) reductions in viable recoverable microorganisms relative to essential oil-free placebos after both 30- and 60-second exposures. When compared to in vitro models previously used to evaluate the antimicrobial activity of dentifrices, this method provides a rapid, reproducible, more biologically representative means of screening dentifrice formulations for microbicidal activity using dilutions and exposure times approximating those achieved during toothbrushing. However, since other factors may influence microbicidal activity of dentifrice formulations in vivo, conclusions drawn using this model require clinical confirmation.

Body mass index profile in Hong Kong Chinese adults

INTRODUCTION

Obesity has now become an epidemic with increasing prevalence in most parts of the world. However, information on the problem of obesity in Asians is limited.

SUBJECTS AND METHODS

From April 1996 to August 1997, 17,121 Chinese adult subjects from the community of Hong Kong presented themselves voluntarily at the United Christian Nethersole Community Health Service Centers for primary health care check-up. Demographic data including height and weight were documented. Their body mass indexes (BMI) were measured. The prevalence rates of overweight and obese subjects were calculated according to the 1995 World Health Organization criteria.

RESULTS

There were 4781 (27.9%) men and 12,340 (72.1%) women. The mean age (+/- SD) was 51.3 +/- 16.0 years (range 20 to 96 years, median 49.8 years). Of the 17,121 subjects, 4939 (28.85%) were overweight and 656 (3.83%) were obese. Based on the 1997 Hong Kong Census statistics of the overall Hong Kong population data, the age-standardised prevalence rates of overweight and obese subjects were 30.52% and 3.19% in men and 22.14% and 3.35% in women, respectively. Of the 10,937 subjects of working age (20 to 65 years), the prevalence rates of overweight and obese subjects were 28.98% and 3.55%, respectively. Of the 6648 subjects aged > or = 60 years, the prevalence rates of overweight and obese subjects were 36.31% and 4.81%, respectively.

CONCLUSIONS

In Hong Kong, the age-standardised prevalence rate of overweight and obese subjects were 30.5% and 3.2% in men and 22.1% and 3.4% in women, respectively. This information provides some useful estimations of the extent of an important public health problem, obesity, in Hong Kong.

Lower BMI cut-off value to define obesity in Hong Kong Chinese: an analysis based on body fat assessment by bioelectrical impedance

There is increasing evidence suggesting that the cut-off values for defining obesity used in the Western countries cannot be readily applied to Asians, who often have smaller body frames than Caucasians. We examined the BMI and body fat (BF) as measured by bioelectrical impedance in 5153 Hong Kong Chinese subjects. We aimed to assess the optimal BMI reflecting obesity as defined by abnormal BF in Hong Kong Chinese. Receiver operating characteristic curve (ROC) analysis was used to assess the optimal BMI predicting BF at different levels. The mean age and SD of the 5153 subjects (3734 women and 1419 men) was 51.5 (SD 16.3) years (range: 18.0-89.5 years, median: 50.7 years). Age-adjusted partial correlation (r) between BMI and BF in women and men were 0.899 (P < 0.001) and 0.818 (P < 0.001) respectively. Using ROC analysis, the BMI corresponding to the conventional upper limit of normal BF was 22.5-23.1 kg/m(2), and the BMI corresponding to the 90 percentiles of BF was 25.4-26.1 kg/m(2). Despite similar body fat contents, the BMI cut-off value used to define obesity in Hong Kong Chinese should be lower as compared to Caucasians. We suggest a BMI of 23 kg/m(2) and 26 kg/m(2) as the cut-off values to define overweight and obesity respectively in Hong Kong Chinese.

Swelling-activated chloride currents in embryonic chick heart cells

AIM

To characterize a swelling-activated chloride current, I(Cl, swell), in white Leghorn chick heart cells and the effects of chlorpromazine (CPZ) effects.

METHODS

The patch-clamp technique in the whole-cell configuration was used.

RESULTS

Hyposmotic swelling elicited I(Cl, swell) in white Leghorn chick heart cells. The current amplitude increased from (452 +/- 200) pA to (849 +/- 373) pA with a reduction of osmolarity from 300 mmol.L-1 to 270 mmol.L-1, 4',4-Diisothiocyanostilbene-2,2'-disulphonic acid (DIDS) 100 mumol.L-1 decreased I(Cl, swell) from (1196 +/- 505) pA to (830 +/- 328) pA in hyposmotic solution. In white Leghorn chick heart cells I(Cl, swell) was not induced by CPZ 30 mumol.L-1, which is different from the case of E coli spheroplast.

CONCLUSION

Swelling-activated chloride current was activated by hyposmotic swelling in white Leghorn chick heart cells. The mechanism for activating the current is different from that of mechanosensitive ion channels of E coli.

Anticalculus effect of two zinc citrate/essential oil-containing dentifrices

PURPOSE

To assess the feasibility of incorporating zinc citrate, a known anticalculus ingredient, into a dentifrice formulation containing a fixed combination of essential oils, a known antiplaque/antigingivitis agent.

MATERIALS AND METHODS

This randomized, parallel, double-blind study evaluated the potential of two essential oil dentifrice formulations containing different levels of zinc citrate (1.0% and 2.0% ZCT) to reduce supragingival calculus formation compared to a marketed control dentifrice, Crest Regular. Following a 3-month pre-test phase, subjects received a dental prophylaxis, were stratified into three balanced groups on the basis of Volpe-Manhold calculus scores and brushed twice daily with their assigned dentifrice for 3 months.

RESULTS

One hundred ninety-six evaluable subjects completed all phases of the study. ANCOVA revealed that the 1.0% ZCT and 2.0% ZCT essential oil dentifrice formulations provided significant reductions in calculus formation of 26.4% and 29.0% (P< 0.001), respectively, compared to the control dentifrice, Crest Regular. The magnitude of calculus reductions is similar to those levels obtained by other zinc salt formulations.

Essential oils in an antiplaque and antigingivitis dentifrice: a 6-month study

PURPOSE

To determine if a dentifrice formulated with the fixed combination of essential oils possessed antiplaque and antigingivitis properties.

MATERIALS AND METHODS

This study was a blinded, randomized, controlled clinical trial. The 6-month study had clinical examinations at baseline, 3 and 6 months. The examinations consisted of three indices; a plaque index, the Modified Gingival Index and a bleeding index.

RESULTS

At 6 months, the essential oil-containing dentifrice group had statistically significantly (P < 0.001) lower whole-mouth and interproximal mean plaque index scores exhibiting mean reductions of 18.3% and 18.1% relative to the vehicle control. At 6 months, the essential oil-containing dentifrice group had statistically significantly (P < 0.001) lower whole-mouth and interproximal mean gingival index scores compared to the vehicle control with reductions of 16.2% and 15.5%, respectively. Finally, for the gingival bleeding index, the essential oil-containing dentifrice group had statistically significantly (P < 0.001) lower whole-mouth and interproximal mean bleeding index scores and reductions of 40.5% and 46.9% at 6 months compared to the vehicle control.

4-aminopyridine, a specific blocker of K(+) channels, inhibited inward Na(+) current in rat cerebellar granule cells

The effects of 4-aminopyridine (4-AP), a specific blocker of outward K(+) current, on voltage-activated transient outward K(+) current (I(K(A))) and inward Na(+) current (I(Na)) were investigated on cultured rat cerebellar granule cells using the whole cell voltage-clamp technique. At the concentration of 1-5 mM, 4-AP inhibited both I(K(A)) and I(Na). It reduced the amplitude of peak Na(+) current without significant alteration of the steady-state activation and inactivation properties. The inhibitory effect was not enhanced by repeated depolarizing pulses (0.5 or 0.1 Hz), suggesting that the binding affinity of 4-AP on Na(+) channels is state-independent. In contrast, the effect of 4-AP on Na(+) channels appeared to be voltage-dependent, the weaker inhibition occurred at more depolarization. Moreover, 4-AP slowed both the activation and inactivation kinetics of Na(+) current. These effects were similar to those induced by alpha-scorpion toxin and sea anemone toxins on Na(+) channels in other cell model. Our data demonstrate for the first time that 4-AP is able to block not only A-type K(+) channels, but also Na(+) channels in rat cerebellar granule cells. It is concluded that the inhibition exerted by 4-AP on Na(+) current likely differs from that provoked by local anesthetics. The possibility that the binding site of neurotoxin receptor 3 may be involved is discussed.

Risk of internal cancers from arsenic in drinking water

The U.S. Environmental Protection Agency is under a congressional mandate to revise its current standard for arsenic in drinking water. We present a risk assessment for cancers of the bladder, liver, and lung from exposure to arsenic in water, based on data from 42 villages in an arseniasis-endemic region of Taiwan. We calculate excess lifetime risk estimates for several variations of the generalized linear model and for the multistage-Weibull model. Risk estimates are sensitive to the model choice, to whether or not a comparison population is used to define the unexposed disease mortality rates, and to whether the comparison population is all of Taiwan or just the southwestern region. Some factors that may affect risk could not be evaluated quantitatively: the ecologic nature of the data, the nutritional status of the study population, and the dietary intake of arsenic. Despite all of these sources of uncertainty, however, our analysis suggests that the current standard of 50 microg/L is associated with a substantial increased risk of cancer and is not sufficiently protective of public health.

Organelle pH studies using targeted avidin and fluorescein-biotin

BACKGROUND

Mammalian organelles of the secretory pathway are of differing pH. The pH values form a decreasing gradient: the endoplasmic reticulum (ER) is nearly neutral, the Golgi is mildly acidic and the secretory granules are more acidic still ( approximately pH 5). The mechanisms that regulate pH in these organelles are still unknown.

RESULTS

Using a novel method, we tested whether differences in H(+) 'leak' and/or counterion conductances contributed to the pH difference between two secretory pathway organelles. A pH-sensitive, membrane-permeable fluorescein-biotin was targeted to endoplasmic-reticulum- and Golgi-localized avidin-chimera proteins in HeLa cells. In live, intact cells, ER pH (pH(ER)) was 7.2 +/- 0.2 and Golgi pH (pH(G)) was 6.4 +/- 0.3 and was dissipated by bafilomycin. Buffer capacities of the cytosol, ER and Golgi were all similar (6-10 mM/pH). ER membranes had an apparent H(+) permeability three times greater than that of Golgi membranes. Removal of either K(+) or Cl(-) did not affect ER and Golgi H(+) leak rates, or steady-state pH(G) and pH(ER).

CONCLUSIONS

The Golgi is more acidic than the ER because it has an active H(+) pump and fewer or smaller H(+) leaks. Neither buffer capacity nor counterion permeabilities were key determinants of pH(G), pH(ER) or ER/Golgi H(+) leak rates.

The effect of having myopic parents: an analysis of myopia in three generations

PURPOSE

The etiology of myopia has been attributed to both genetic and environmental factors. The purpose of this paper is to attempt to distinguish between genetic and environmental factors in three generations of subjects from three locations.

METHODS

Noncycloplegic autorefraction and distance visual acuity were measured in 3131 Chinese children 7 to 17 years old from Hong Kong, Tianjin, and Ban Chau. Data on the refractive status of the parents and grandparents were collected using questionnaires. Myopia was defined operationally as spherical equivalent refractive error (SER) of at least -1.00 D and uncorrected vision worse than logMAR 0.18 (6/9).

RESULTS

The odds of having myopia for the grandparents', parents', and children's generations were 0.06, 0.26, and 0.35, respectively. Having myopic parents increased the odds ratio for having myopia (odds ratio 1.85 for children's generation and 6.71 for parents' generation), showing a genetic influence. However, the odds of having myopia also increased in offspring of nonmyopic parents between generation 2 and 3, suggesting an environmental influence. Results of prevalence and odds ratios from the three locations also demonstrated an environmental effect on development of myopia.

CONCLUSION

We propose that myopic development in Chinese follows a multifactorial and polygenic model in which the genetic input has remained constant while the environmental influence has increased over the last three generations.

Fluconazole prophylaxis prevents intra-abdominal candidiasis in high-risk surgical patients

OBJECTIVE

To evaluate the efficacy and safety of intravenous fluconazole for the prevention of intra-abdominal Candida infections in high-risk surgical patients.

DESIGN

Randomized, prospective, double-blind, placebo-controlled study.

SETTING

Two university-affiliated hospitals in Switzerland.

PATIENTS

Forty-nine surgical patients with recurrent gastrointestinal perforations or anastomotic leakages.

INTERVENTIONS

Prophylaxis with intravenous fluconazole (400 mg per day) or placebo continued until resolution of the underlying surgical condition.

MEASUREMENTS AND MAIN RESULTS

Patients were evaluated daily, and specimens for culture were obtained three times per week during prophylaxis. The primary study end points were the frequency of and the time to intra-abdominal Candida infections. Secondary end points were the frequency of candidiasis (intra-abdominal and extra-abdominal) and the emergence or persistence of Candida colonization. Among patients who were not colonized at study entry, Candida was isolated from surveillance cultures during prophylaxis in 15% of the patients in the fluconazole group and in 62% of the patients in the placebo group (relative risk, 0.25; 95% confidence interval, 0.07 to 0.96; p = .04). Candida peritonitis occurred in one of 23 patients (4%) who received fluconazole and in seven of 20 patients (35%) who received placebo (relative risk, 0.12; 95% confidence interval, 0.02 to 0.93; p = .02). In addition, one catheter-related Candida albicans sepsis occurred in a fluconazole-treated patient. Thus, overall, candidiasis developed in two fluconazole patients and seven placebo patients (relative risk, 0.25; 95% confidence interval, 0.06 to 1.06; p = .06). C. albicans accounted for 87% of the Candida species isolated before or during prophylaxis, and all C. albicans strains were susceptible to fluconazole. Fluconazole was well tolerated, and adverse events occurred at similar frequencies in both treatment groups.

CONCLUSIONS

Fluconazole prophylaxis prevents colonization and invasive intra-abdominal Candida infections in high-risk surgical patients.

DNA repair methyltransferase (Mgmt) knockout mice are sensitive to the lethal effects of chemotherapeutic alkylating agents

We have generated mice deficient in O6-methylguanine DNA methyltransferase activity encoded by the murine Mgmt gene using homologous recombination to delete the region encoding the Mgmt active site cysteine. Tissues from Mgmt null mice displayed very low O6-methylguanine DNA methyltransferase activity, suggesting that Mgmt constitutes the major, if not the only, O6-methylguanine DNA methyltransferase. Primary mouse embryo fibroblasts and bone marrow cells from Mgmt -/- mice were significantly more sensitive to the toxic effects of the chemotherapeutic alkylating agents 1,3-bis(2-chloroethyl)-1-nitrosourea, streptozotocin and temozolomide than those from Mgmt wild-type mice. As expected, Mgmt-deficient fibroblasts and bone marrow cells were not sensitive to UV light or to the crosslinking agent mitomycin C. In addition, the 50% lethal doses for Mgmt -/- mice were 2- to 10-fold lower than those for Mgmt +/+ mice for 1,3-bis(2chloroethyl)-1-nitrosourea, N-methyl-N-nitrosourea and streptozotocin; similar 50% lethal doses were observed for mitomycin C. Necropsies of both wild-type and Mgmt -/mice following drug treatment revealed histological evidence of significant ablation of hematopoietic tissues, but such ablation occurred at much lower doses for the Mgmt -/- mice. These results demonstrate the critical importance of O6-methylguanine DNA methyltransferase in protecting cells and animals against the toxic effects of alkylating agents used for cancer chemotherapy.

Low-threshold lasing of a Rhodamine dye solution embedded with nanoparticle fractal aggregates

The spectral and temporal emission properties of a Rhodamine (Rh) dye solution embedded with nanoparticle fractal aggregates are studied. An experiment on the pump-power density dependence of Rh emission spectra shows that the lasing threshold of a Rh6G solution embedded with TiO(2) nanoparticle fractal aggregates is significantly reduced compared with that of a neat dye solution. The mechanism of this reduction in lasing threshold is discussed, together with the lasing properties of narrow bandwidth and short duration.

A chemical and genetic approach together define the biological consequences of 3-methyladenine lesions in the mammalian genome

DNA-damaging agents produce a plethora of cellular responses that include p53 induction, cell cycle arrest, and apoptosis. It is generally assumed that it is the DNA damage produced by these agents that triggers such responses, but there is limited direct evidence to support this assumption. Here, we used DNA alkylation repair proficient and deficient isogenic mouse cell lines to demonstrate that the signal to trigger p53 induction, cell cycle arrest, and apoptosis in response to alkylating agents does emanate from DNA damage. Moreover, we established that 3-methyladenine, a relatively minor DNA lesion produced by most methylating agents (which form mainly 7-methylguanine), can specifically induce sister chromatid exchange, chromatid and chromosome gaps and breaks, S phase arrest, the accumulation of p53, and apoptosis. This study was made possible by the generation of 3-methyladenine DNA glycosylase null mutant cells by targeted homologous recombination and by the chemical synthesis of a methylating agent that almost exclusively produces 3-methyladenine DNA lesions. The combined use of these two experimental tools has defined the biological consequences of 3-methyladenine, a DNA lesion produced by endogenous cellular metabolites, environmental carcinogens, and chemotherapeutic alkylating agents.

Effect of exercise and dietary restraint on energy intake of reduced-obese women

Self-selected food intake of 15 reduced-obese women living in a metabolic ward was studied for 14 consecutive days to determine the effect of exercise and other metabolic and behavioral variables on energy intake. A choice of prepared food items were offered at breakfast, lunch and dinner, and a variety of additional food items were available continuously 24 h/day. Subjects performed either moderate intensity aerobic exercise (A-EX) (n = 8) expending 354 +/- 76 kcal/session or low intensity resistance weight training (R-EX)(n =7) expending 96 +/- kcal/session, 5 days/week. Mean energy intakes (kcal/day, +/- SEM) of the exercise groups were similar: 1867 +/- 275 for A-EX, 1889 +/- 294 for R-EX. Mean energy intakes of individuals ranged from 49 to 157% of the predetermined level required for weight maintenance. Resting metabolic rate per kg 0.75 and the Eating Inventory hunger score contributed significantly to the between subject variance in energy intake, whereas exercise energy expenditure did not. Regardless of exercise, eight women consistently restricted their energy intake (undereaters), and seven other consumed excess energy (overeaters). Overeaters were distinguished by higher Eating Inventory disinhibition (P = 0.023) and hunger (p = 0.004) scores. The overeaters' diet had a higher fat content 34 +/- 1% (p = 0.007). Also, overeaters took a larger percentage of their daily energy, than that of undereaters, 27 +/- 1 energy intake in the evening, 13 +/- 2%, compared to undereaters, 7 +/- 1% (p = 0.005). We conclude that the Eating Inventory is useful for identifying reduced-obese women at risk of overeating, and these individuals may benefit from dietary counseling aimed at reducing fat intake and evening snacking.

Activity-related features of synapse morphology: a study of endbulbs of held

The myelinated fibers of the auditory nerve can be divided into two separate populations on the basis of sensitivity to sound, average levels of spike activity, and central branching patterns. The synaptic endings of these populations were investigated for the presence of structural specializations that might correlate with levels of neural activity. We applied intracellular recording and staining methods in cats to analyze directly the relationship between spike activity and the structure of synapses using endbulbs of Held, the large synaptic endings in the anteroventral cochlear nucleus. Endbulbs from fibers having low or high levels of activity were examined and compared using light and electron microscopic methods. All endbulbs exhibited relatively large but incomplete coverage by one-to-several lamellae of glial processes. Endbulbs of high activity fibers were large and contained larger mitochondria than endbulbs of low activity fibers. Furthermore, the synapses of high activity endbulbs were on average smaller but more numerous, possessed greater numbers of associated synaptic vesicles, and exhibited greater curvature of their postsynaptic densities. These structural features are hypothesized to reflect specializations that optimize synaptic transmission.

Multiple risk factors associated with arsenic-induced skin cancer: effects of chronic liver disease and malnutritional status

In order to evaluate the prevalence and multiple risk factors of arsenic-induced skin cancer among residents in Taiwanese villages in which chronic arseniasis is hyperendemic, a total of 1571 subjects aged 30 or more years were recruited between September 1988 and March 1989. All of them were interviewed personally by a public health nurse using a structured questionnaire, and 1081 interviewed study subjects, including 468 men and 613 women, participated in physical examination, giving a participation rate of 68.8%. The overall prevalence of skin cancer was as high as 6.1%, showing an increase with age in both men and women. There was a significant dose-response relation between skin cancer prevalence and chronic arsenic exposure as indexed by duration of residence in the endemic area, duration of consumption of high-arsenic artesian well water, average arsenic exposure in parts per million (p.p.m.) and cumulative arsenic exposure in p.p.m.-years. Chronic carriers of hepatitis B surface antigen with liver dysfunction had an increased prevalence of skin cancer. Undernourishment, indexed by a high consumption of dried sweet potato as a staple food, was also significantly associated with an increased prevalence of arsenic-induced skin cancer. All these risk factors remained statistically significant in the multiple logistic regression analysis. Consistent with animal experiments, the findings imply that liver function and nutritional status may affect the metabolism of inorganic arsenic and the development of subsequent skin cancers.

Increased prevalence of hypertension and long-term arsenic exposure

To examine the association between long-term exposure to inorganic arsenic and the prevalence of hypertension, we studied a total of 382 men and 516 women residing in villages where arseniasis was hyperendemic. Hypertension was defined as a systolic blood pressure of 160 mm Hg or greater, a diastolic blood pressure of 95 mm Hg or greater, or a history of hypertension treated regularly with antihypertensive drugs. The long-term arsenic exposure was calculated from the history of artesian well water consumption obtained through standardized interviews based on a structured questionnaire and the measured arsenic concentration in well water. Residents in villages where long-term arseniasis was hyperendemic had a 1.5-fold increase in age- and sex-adjusted prevalence of hypertension compared with residents in nonendemic areas. Duration of artesian well water consumption, average arsenic concentration in drinking water, and cumulative arsenic exposure were all significantly associated with hypertension prevalence. The higher the cumulative arsenic exposure, the higher the prevalence of hypertension. This dose-response relation remained significant after adjustment for age, sex, diabetes mellitus, proteinuria, body mass index, and serum triglyceride level. The results suggest that long-term arsenic exposure may induce hypertension in humans.

Effects of a carotene-deficient diet on measures of oxidative susceptibility and superoxide dismutase activity in adult women

The effect of consuming a low carotene diet (approximately 60 micrograms carotene/day) on oxidative susceptibility and superoxide dismutase (SOD) activity in women living in a metabolic research unit was evaluated. The diet had sufficient vitamins A, E, and C. The women ate the diet supplemented with 1500 micrograms/day beta-carotene for 4 days (baseline), then the unsupplemented diet for 68 days (depletion), followed by the diet supplemented with > 15,000 micrograms/day carotene for 28 days (repletion). Production of hexanal, pentanal, and pentane by copper-oxidized plasma low density lipoproteins from carotene-depleted women was greater than their production of these compounds when repleted with carotene. Erythrocyte SOD activity was depressed in carotene-depleted women; it recovered with repletion. Thiobarbituric acid reactive substances in plasma of carotene-depleted women were elevated and diminished with repletion. Dietary carotene seems to be needed, not only as a precursor of vitamin A, but also to inhibit oxidative damage and decrease oxidation susceptibility.

Effect of a low beta-carotene diet on the immune functions of adult women

We examined the effect of beta-carotene depletion and repletion on the immune status of nine healthy women who lived in the metabolic suite for 100 d. For the first 4 d all women were fed a basal diet supplemented with 1.5 mg beta-carotene/d (baseline). During the next 68 d, the basal diet without beta-carotene supplementation was fed to all subjects (depletion), and during the last 28 d the diet of each women was supplemented with 15.0 mg beta-carotene/d (repletion). Neither beta-carotene depletion nor repletion significantly (P < or = 0.05) altered proliferation of peripheral blood mononuclear cells cultured with phytohemagglutinin or concanavalin A, in vitro production of soluble interleukin 2 receptor, or the concentration of circulating lymphocytes and their subsets. Thus, in healthy adults consuming adequate vitamin A, beta-carotene depletion had no adverse effect on the indexes tested, nor was there any beneficial effect of modest beta-carotene supplementation.

Decreased systemic thromboxane A2 biosynthesis in normal human subjects fed a salmon-rich diet

Nine normal male subjects were fed a reference diet typical of that consumed in the United States and a diet containing approximately 450 g salmon (salmon-rich diet). The salmon diet contained approximately 6 g omega 3 fatty acids that comprised 2.0% energy intake/d for each individual. The percent energy contribution of protein, carbohydrate, and fat (19%, 56%, and 25%, respectively) was identical for the two diets. Urinary excretion of 2,3-dinor-thromboxane B2 was significantly lower (0.74 +/- 0.26 ng/24 h) with the salmon diet compared with the reference diet (0.95 +/- 0.31 ng/24 h). In addition, in vitro generation of thromboxane B2 in response to collagen-stimulated aggregation of platelet-rich plasma from subjects consuming the salmon diet was reduced (1.87 +/- 0.79 ng/mL) compared with subjects consuming the reference diet (3.10 +/- 1.81 ng/mL). Urinary 2,3-dinor-6-oxo-prostaglandin F1 alpha excretion in subjects was not significantly different between the salmon diet (0.69 +/- 0.33 ng/24 h) and the reference diet (0.81 +/- 0.44 ng/24 h).

Homocysteine increases as folate decreases in plasma of healthy men during short-term dietary folate and methyl group restriction

Ten healthy adult men were fed a diet low in folate and exogenous methyl groups to study the effects on folate requirement and status. The men were housed in a metabolic unit for the entire 108-d study. After a 9-d base-line period (P1), the men were fed an amino acid-defined soybean product diet for 45 d, which provided 25 micrograms/d of folate for 30 d (P2) and (with a folate supplement) 99 micrograms/d for 15 d (P3). During P2 and P3, the low methionine and choline diet was supplemented with methionine for half the subjects to vary the dietary methyl group intake. The periods were then repeated over the next 54 d (P4-P6), with a cross-over of methionine intakes in P5 and P6. Restricting dietary methyl group intake did not increase the dietary folate requirement. Plasma total homocysteine rose during folate depletion and correlated inversely with plasma folate; however, the response of homocysteine to changes in folate intake varied among individuals from very strong to absent. The results support previous suggestions that increased plasma homocysteine concentrations provide a marker of functional folate deficiency, and further indicate that individuals may differ greatly in their susceptibility to hyperhomocysteinemia due to low folate intakes. Judged by the lack of normalization of high homocysteine concentrations during folate repletion, the current folate RDA for adult men may not provide the expected margin of protection.

Moderate diet restriction alters the substrate and hormone response to exercise

Substrate and hormone responses to submaximal exercise were studied in 10 overweight women (119-141% ideal body weight) to learn if a moderately restricted diet would influence the responses. Subjects consumed diets with adequate energy (ADEX), N = 5, or low energy (LDEX)--50% reduction in energy, N = 5. Three times during the 12-wk study, blood was drawn before and immediately following exercise; results were combined since there were no differences between replicates. Postexercise free fatty acids and glycerol increased to 465 +/- 27 mg.l-1 in LDEX but only to 245 +/- 19 mg.l-1 in ADEX. Postexercise insulin increased to 129 +/- 13 pmol.l-1 in LDEX, but did not increase in ADEX. Postexercise growth hormone increased to 10.5 +/- 1.0 microgram.l-1 in ADEX but only to 6.6 +/- 1.0 microgram.l-1 in LDEX. All postexercise increases within diet groups were highly significant (P < 0.0001), and the postexercise responses between diet groups were also different (P < 0.01). Respiratory gas exchange indicated that both groups increased fat utilization during exercise, but diet restriction altered postexercise hormones so that fat mobilization and utilization might be inhibited. The postexercise recovery period should be studied further to determine whether diet restriction results in a sustained altered hormone pattern that would curtail lipolysis and possibly limit body fat loss.

Ingested inorganic arsenic and prevalence of diabetes mellitus

To examine the association between ingested inorganic arsenic and prevalence of diabetes mellitus, in 1988, the authors studied 891 adults residing in villages in southern Taiwan where arseniasis is hyperendemic. The status of diabetes mellitus was determined by an oral glucose tolerance test and a history of diabetes regularly treated with sulfonylurea or insulin. The cumulative arsenic exposure in parts per million-years was calculated from the detailed history of residential addresses and duration of drinking artesian well water obtained through standardized interviews based on a structured questionnaire and the arsenic concentration in well water. The body mass index was derived from body height and weight measured according to a standard protocol, while the physical activity at work was also obtained by questionnaire interviews. Residents in villages where the chronic arseniasis was hyperendemic had a twofold increase in age- and sex-adjusted prevalence of diabetes mellitus compared with residents in Taipei City and the Taiwan area. There was a dose-response relation between cumulative arsenic exposure and prevalence of diabetes mellitus. The relation remained significant after adjustment for age, sex, body mass index, and activity level at work by a multiple logistic regression analysis giving a multivariate-adjusted odds ratio of 6.61 and 10.05, respectively, for those who had a cumulative arsenic exposure of 0.1-15.0 and greater than 15.0 ppm-year compared with those who were unexposed. These results suggest the chronic arsenic exposure may induce diabetes mellitus in humans.

Prevalence of human papillomaviruses 16 and 18 in transitional cell carcinoma of bladder

It has been speculated that human papillomaviruses (HPV) might be a causative agent of transitional cell carcinoma of the bladder. With the polymerase chain reaction technic, fresh specimens of 53 transitional cell carcinomas of the bladder were examined, and bladder epithelium from 12 patients with hyperplasia of prostate and peripheral blood lymphocytes of 8 normal individuals served as controls. The primers set for HPV-16 and 18 were selected from E6/E7 regions of open reading frames. HPV-16 was positive in 52.8% of the specimens examined, whereas HPV-18 positive in only 3.7%. No controls showed either HPV-16 or 18. Reports on the role of HPVs in carcinogenesis of bladder are scanty and yet there exist conspicuous discrepancies among them. There is a diversity of opinions on the contamination and variation of technical procedures. More work should be done before the relationship between HPV-16 and development of bladder carcinoma can be clarified.

Biomechanical performance of microsurgical spatula needles for the repair of nail bed injuries

The purpose of this study was to determine the mechanical performance of microsurgical spatula needles for repair of nail bed injuries. Standard biomechanical tests have been devised to evaluate the performance of microsurgical spatula needles. Two comparable groups of microsurgical spatula needles were selected from two different manufacturers for these biomechanical studies. The results of this testing demonstrated that needle point geometry and needle composition were important determinants of needle performance. When needles of comparable size were evaluated, the biomechanical performance of the CS160-8 spatula needle (Ethicon, Inc., Somerville, NJ) was superior to the C-5 spatula needles (Alcon, Inc., Fort Worth, TX). While the development of these biomechanical tests has allowed the evaluation of these microsurgical spatula needles, these same tests can be used to assess the performance of new microsurgical spatula needles.

Cancer potential in liver, lung, bladder and kidney due to ingested inorganic arsenic in drinking water

In order to compare risk of various internal organ cancers induced by ingested inorganic arsenic and to assess the differences in risk between males and females, cancer potency indices were calculated using mortality rates among residents in an endemic area of chronic arsenicism on the southwest coast of Taiwan, and the Armitage-Doll multistage model. Based on a total of 898,806 person-years as well as 202 liver cancer, 304 lung cancer, 202 bladder cancer and 64 kidney cancer deaths, a significant dose-response relationship was observed between arsenic level in drinking water and mortality of the cancers. The potency index of developing cancer of the liver, lung, bladder and kidney due to an intake of 10 micrograms kg day of arsenic was estimated as 4.3 x 10(-3), 1.2 x 10(-2), 1.2 x 10(-2), and 4.2 x 10(-3), respectively, for males; as well as 3.6 x 10(-3), 1.3 x 10(-2), 1.7 x 10(-2), and 4.8 x 10(-3), respectively, for females in the study area. The multiplicity of inorganic arsenic-induced carcinogenicity without showing any organotropism deserves further investigation.

Relationship between fatty liver, alanine aminotransferase, HBsAg and hepatitis C virus

A community health survey of 923 residents aged 30 years or more was performed in Putai Township of Taiwan. To elucidate the relationships between hepatitis C virus (HCV) and surrogate tests for non-A, non-B hepatitis in hyperendemic areas of hepatitis B virus (HBV) serum levels of alanine aminotransferase (ALT), triglycerides, cholesterol, hepatitis B surface antigen (HBsAg) and antibody to HCV (anti-HCV) were examined. Glucose tolerance tests and the history of diabetes treatment were used to define the diabetes status. Fatty liver was diagnosed by sonography. The prevalence of anti-HCV was 2.6% (95% confidence interval, 1.6-3.6%). Elevated ALT and fatty liver were significantly associated with anti-HCV in univariate analysis. Anti-HCV was not an associated factor for fatty liver after adjusting for serum triglycerides and cholesterol, sex, body mass index and diabetes status through multiple logistic regression. However elevated ALT was still associated with anti-HCV after adjusting for serum triglycerides, sex, body mass index, HBsAg and age through multiple linear regression. The anti-HCV prevalence was similar between HBsAg-positive and negative subjects. Aggregation of HCV infection was found among spouses. It was concluded that elevated ALT and intimate contact with HCV carriers might be associated factors for HCV infection, and that HBV infection and fatty liver were not related to HCV infection in Taiwan.

A novel score for predicting the mortality of septic shock patients

OBJECTIVE

To establish a prognostic scoring system for septic shock patients.

DESIGN

The clinical, biological, and hemodynamic data of these patients were retrospectively explored to select variables independently associated with outcome. According to the risk of death, ratings from 0 to 2 points were attributed to each value.

SETTING

Medical intensive care service of a 1,000-bed tertiary care university medical center.

PATIENTS

Eighty-eight patients in septic shock in whom hemodynamic measurements were performed using pulmonary artery flotation catheters.

RESULTS

Fourteen clinical, biological, and hemodynamic variables were selected and rated for each patient. A Simplified Septic Shock Score, available immediately after admission and catheterization, was established by adding the rates of these variables. The mean Simplified Septic Shock Score was 2.5 +/- 1.7 (SD) in 43 survivors and 6.5 +/- 2.3 in 45 nonsurvivors (p less than .0001). Some underlying diseases and characteristics of infections also correlated with the outcome. Further ratings from 0 to 2 points were attributed to these conditions. A Complete Septic Shock Score was calculated by adding these rates to the Simplified Septic Shock Score. The Complete Septic Shock Score had a slightly better prognostic value than the Simplified Septic Shock Score, but it could be determined only after the availability of the microbiological data. The mean Complete Septic Shock Score was 3.1 +/- 1.9 in survivors and 8.4 +/- 2.6 in nonsurvivors (p less than .0001). Both Simplified and Complete Septic Shock Scores showed better association with patient outcome than the Simplified Acute Physiology Score or the Acute Physiology and Chronic Health Evaluation (APACHE II) score.

CONCLUSIONS

The Simplified and the Complete Septic Shock Scores are simple scoring systems that appear to predict the outcome of septic shock patients more accurately than general scoring systems, such as the Simplified Acute Physiology Score and APACHE II score. These septic shock scores might be useful in assessing the severity of septic shock patients.

Technical considerations in manual and instrument tying techniques

The purpose of this study was to relate the two-hand (manual) and instrument tie techniques with the ultimate security of granny and square knots constructed in multifilament and monofilament nylon sutures. Instrument-tie technique constructed secure granny and square knots, which failed by breakage rather than slippage. Similarly, two-hand (manual) tie techniques constructed square knots, which achieved knot security, failing only by breakage. In contrast, knot security was not reliably achieved with granny knots constructed by the two-hand (manual) tie techniques, with the knots frequently failing by slippage.