Adverse pregnancy outcome in a petrochemical polluted area in Taiwan

The petrochemical industry is the main source of industrial air pollution in Taiwan. Reported here are the results from an ongoing study of outdoor air pollution and the health of individuals living in a community in close proximity to petrochemical industrial complexes. The prevalences of term low birth weight (LBW) in the petrochemical municipality and control municipality were 3.22%, and 1.84%, respectively. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.767 (1.002-3.116) for term LBW in the petrochemical municipality. Data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy.

Inhibition of proteasome function induced apoptosis in gastric cancer

The ubiquitin-proteasome pathway plays a critical role in the degradation of cellular proteins and cell cycle control. Dysregulating the degradation of such proteins should have profound effects on tumor growth and causes cells to undergo apoptosis. The aims of this study are to evaluate the ubiquitin-proteasome pathway in gastric cancer and the potential role of pharmacological inhibition of proteasome on induction of apoptosis in gastric cancer cells. Gastric cancer cell lines AGS (p53 wild-type) and MKN-28 (p53 mutant) were treated with proteasome inhibitor MG132. The results showed that MG132 inhibited cell proliferation in AGS and MKN-28 cells in a time- and dose-dependent manner. The inhibition of cell proliferation was caused by apoptosis which was also time- and dose-dependent. AGS cells were more responsive to MG132 than MKN-28 cells. Induction of apoptosis was preceded by the activation of caspase-3, as measured by a colorimetric caspase-3 cellular activity and Western blotting of the cleavage of caspase-3 and its substrate PARP. Activation of caspase-7 was also exhibited. In addition, z-VAD-fmk, a broad spectrum caspase inhibitor, reversed apoptosis induced by MG132 in AGS and MKN28 cells. Although z-DEVD-fmk, a specific caspase-3 inhibitor, suppressed MG132-induced apoptosis in MKN28 cells, it only partially rescued the apoptotic effect in AGS cells. Caspase-3 activation was the result of release of cytochrome c from mitochondria into the cytosol, as a consequence of upregulation of bax. There were overexpressions of all the proteasome-related proteins p53, p21(waf1) and p27(kip1) at 4 hr after proteasome inhibition which was identified by the accumulation of ubiquitin-tagged proteins. This was accompanied by accumulation of cells at G(1) phase. Our present study suggests that inhibition of proteasome function in gastric cancer cells induces apoptosis and proteasomal inhibitors have potential use as novel anticancer drugs in gastric cancer.

The Berkeley Contact Lens Extended Wear Study. Part I : Study design and conduct

OBJECTIVE

The primary aim of the Berkeley Contact Lens Extended Wear Study (CLEWS) was to test the hypotheses that extended wear of rigid gas-permeable (RGP) contact lenses with greater oxygen permeability (Dk) reduces the incidence of contact lens-associated keratopathy (CLAK) and increases the survival rate in RGP extended wear (EW). In this article we describe the clinical trial design in detail, present the results of subject recruitment and retention, and provide the baseline demographic and ocular characteristics of the CLEWS subjects, whose data will be analyzed to address the study aims in a companion article.

DESIGN

A randomized, concurrently controlled clinical trial.

INTERVENTION

Subjects were fitted with day wear (DW) high-Dk RGP lenses and then adapted to EW. Subjects who adapted to EW were then randomly assigned to either high- or medium-Dk RGP lenses for 12 months of 6-nights/week EW.

MAIN OUTCOME MEASURES

Slit-lamp assessment and grading of 17 possible keratopathies, measurement of refractive error and corneal curvature, and symptoms. Follow-up data were collected every 3 months.

RESULTS

From 545 subjects entering the DW adaptation phase, 201 adapted to EW and were randomly assigned to medium- or high-Dk lenses for 12 months of EW. The baseline characteristics of the two study groups were similar and did not differ from the 344 DW subjects who failed to adapt to EW. The distributions of oxygen transmissibility for the two study groups were disjoint, indicating that each group received distinctly different levels of hypoxia.

CONCLUSIONS

We show that CLEWS was appropriately designed to address the study hypotheses, was conducted with regard for the safety of the subjects, and adhered to rigorous protocols designed to control for bias and ensure the integrity of study data. We establish the internal validity of between-group statistical comparisons and characterize our study population to permit informed evaluation of the applicability of our results to the contact lens-wearing population in general.

The Berkeley Contact Lens Extended Wear Study. Part II : Clinical results

OBJECTIVE

To describe the principal clinical outcomes associated with 12 months use of rigid gas-permeable (RGP) extended wear contact lenses and address two primary study questions: (1) does extended wear (EW) of high oxygen transmissibility (Dk/t) RGP lenses reduce the incidence of ocular complications, and (2) does the wearing of high-Dk/t lenses reduce the rate of failure to maintain 6-night RGPEW over 12 months?

DESIGN

A randomized, concurrently controlled clinical trial.

INTERVENTION

Subjects who adapted to EW with high Dk (oxygen permeability) RGP lenses were randomized to either high Dk or medium-Dk RGP lenses for 12 months of 6-night EW.

MAIN OUTCOME MEASURES

Contact lens-associated keratopathies (CLAK), changes in refractive error and corneal curvature, and survival in EW.

RESULTS

Two hundred one subjects were randomized to medium or high-Dk lenses for 12 months of EW. Sixty-two percent of the subjects in each group completed 12 months of EW; however, the probability of failure was significantly greater for the medium-Dk group. Although the risk of complications was similar for the two groups, the number of CLAK events that led to termination were 16 versus 5 for the medium-Dk and high-Dk groups, respectively. This suggests that the type of adverse response or the inability to reverse an adverse event was different for the group being exposed to the lower oxygen dose.

CONCLUSIONS

The level of oxygen available to the cornea has a significant impact on maintaining successful RGP extended contact lens wear, but not on the initial onset of CLAK. The number of clinical events leading to termination was substantially higher for the medium Dk group, which suggests that corneal hypoxia is an important factor in the development of CLAK. Although overnight contact lens wear should be recommended with caution and carefully monitored for early detection of ocular complications, it appears that high-Dk RGP lenses can be a safe and effective treatment for correction of refractive error for most individuals who can adapt to EW.

Limited cutaneous systemic sclerosis: report of one case

We report a case of systemic sclerosis, limited type, in a 5 year old boy in Taiwan. He presented with erythema, tight skin over his face and digits, subcutaneous calcification, telangiectasis, as well as Raynaud's phenomenon. The laboratory data showed weakly positive antinuclear antibody (ANA), and Topoisomerase 1 antibody (anti-Scl-70) titers. However his esophagogram, CO diffusion capacity, as well as cardiac and renal function were all normal. He suffered from the skin change for 2 to 3 years before visiting our pediatric clinic when he was 7 years old. We gave him Dipyridamole, D-penicillamine, Colchicine, and Nifedipine. There was some remission of the scleroderma and Raynaud's phenomenon after our treatment.

Tamoxifen-induced Ca2+ mobilization in bladder female transitional carcinoma cells

This study examined the effect of tamoxifen, an anti-breast cancer drug, on Ca2+ handling in bladder female transitional cancer cells. Changes in cytosolic free Ca2+ levels were recorded by using the Ca2+-sensitive dye fura-2. In a dose-dependent manner, tamoxifen induced intracellular free Ca2+ concentrations ([Ca2+]i) increases between 5 and 20 microM with an EC50 of 10 microM. External Ca2+ removal reduced the response by 60+/-6%. Addition of 3 mM Ca2+ caused a [Ca2+]i increase after pretreatment with 10 microM tamoxifen in Ca2+-free medium. In Ca2+-free medium, pretreatment with 10 microM tamoxifen abolished the [Ca2+]i increase induced by 1 microM thapsigargin, an endoplasmic reticulum Ca2+ pump inhibitor. Conversely, pretreatment with 1 microM thapsigargin prevented tamoxifen from releasing more Ca2+. Inhibition of phospholipase C-dependent inositol 1,4,5-tris-phosphate formation with 2 microM U73122 did not alter 10 microM tamoxifen-induced Ca2+ release. The [Ca2+]i increase induced by 5 microM tamoxifen was not altered by 10 microM La3+, nifedipine, verapamil, and diltiazem. Collectively, it was found that tamoxifen increased [Ca2+]i in bladder cancer cells by releasing Ca2+ from the endoplasmic reticulum Ca2+ stores in a manner independent of phospholipase C activity, and by inducing Ca2+ entry from external medium.

Characterization of activated carbons prepared from sugarcane bagasse by ZnCl2 activation

Activated carbons were prepared from the agricultural waste of sugarcane bagasse by the chemical activation with zinc chloride (ZnCl2) at the activation temperature of 500 degrees C with soaking time of 0.5 hour. The influence of activation parameters on the final carbon products was examined by varying the impregnation ratio (i.e., mass ratio of added ZnCl2 to bagasse) and bagasse size. The physical properties of carbon products were characterized by nitrogen adsorption/desorption isotherms (at 77 K) and helium displacement method. The surface area and pore volume of carbons were thus obtained by the BET equation and t-plot method. Also, the particle density and porosity of carbons were estimated by the total pore volume and true density. The increases of the values of surface area and pore volume are approximately proportional to the impregnation ratio. The microporous carbon product with the BET surface area of 905 m2/g and total pore volume of 0.44 cm3/g was obtained in the present study. Further, the adsorption isotherms of two acid dyes from aqueous solutions onto the carbon products were performed at 30 degrees C. The results show that the adsorption isotherms of acid dyes with high molecular weight or large molecular size on the microporous adsorbents of activated carbons are plateau forms, indicating multilayer adsorptions, which may be attributed to the steric hindrance of the adsorbate molecules.

State of complementary and alternative medicine in cardiovascular, lung, and blood research: executive summary of a workshop

The National Heart, Lung, and Blood Institute and the National Center for Complementary and Alternative Medicine recently cosponsored a workshop on the use of complementary and alternative medicine (CAM) in cardiovascular, lung, and blood research. In view of the increasing use of CAM by the general public, it is imperative to promote credible research by the established biomedical community. The goal of this workshop was to enhance the exchange of information and ideas between alternative medicine practitioners and scientists in cardiovascular, lung, and blood research and to foster collaborative research among these researchers. The workshop focused on 5 areas of research, including a historical and cultural perspective of CAM, methodological issues in clinical trials, herbal medicine, chelation therapy, mind/body (meditation) therapy, and acupuncture. CAM has become widely used without rigorously proven efficacy and safety. To protect the public, it was recommended that the fundamental mechanistic research for these CAM approaches be vigorously pursued and that any large-scale clinical trial be carefully executed to avoid any waste of resources and any unnecessary risk. It was felt that standardization of botanical products and procedure-based CAM intervention, such as acupuncture and meditation, is essential for meaningful basic and clinical research. Although botanical products properly consumed are perceived as generally safe, potential herb-drug interactions are a major safety concern. Clearly, many challenges need to be addressed by the scientific community before the public can be assured of the proper use of CAM.

Evaluation of Etest for direct antifungal susceptibility testing of yeasts in positive blood cultures

The performance of the Etest (AB BIODISK, Solna, Sweden) for direct antifungal susceptibility testing of yeasts in positive blood cultures was compared with that of the macrodilution method for determining the MICs of five antifungal agents. Culture broths with blood from bottles positive for yeasts were inoculated directly onto plates for susceptibility testing with the Etest, and the MICs were read after 24 and 48 h of incubation. A total of 141 positive blood cultures (72 cultures of Candida albicans, 31 of Candida tropicalis, 14 of Candida glabrata, 11 of Candida parapsilosis, 3 of Candida krusei, and 3 of Cryptococcus neoformans, 4 miscellaneous yeast species, and 3 mixed cultures) were tested, and the rates of MIC agreement (+/-1 log(2) dilution) between the direct Etest (at 24 and 48 h, respectively) and macrodilution methods were as follows: amphotericin B, 81.8 and 93.5%; flucytosine, 84.8 and 87.7%; fluconazole, 89.4 and 85.5%; itraconazole, 69.7 and 63.8%; ketoconazole, 87.9 and 79.0%. By a large-sample t test, the difference in log(2) dilution between the direct Etest and the macrodilution method was found to be small (P < 0.05). The lone exceptions were ketoconazole at 48 h of incubation and itraconazole at both 24 and 48 h of incubation (P > 0.05). By Tukey's multiple comparisons, the difference between the direct Etest (48 h) and reference methods among different species was found to be less than 1 log(2) dilution. When the MICs were translated into interpretive susceptibility, the minor errors caused by the direct Etest (at 24 and 48 h, respectively) were as follows: flucytosine, 2.3 and 1.4%; fluconazole, 3.0 and 3.6%; itraconazole, 21.2 and 21.3%. Itraconazole also produced an additional 3.0 and 3.6% major errors as determined by the direct Etest at 24 and 48 h, respectively. It was concluded that, except for itraconazole, the Etest method was feasible for direct susceptibility testing of blood cultures positive for yeasts. The method is simple, and the results could be read between 24 and 48 h after direct inoculation, whenever the inhibition zones were discernible.

Pulmonary function and spinal characteristics: their relationships in persons with idiopathic and postpoliomyelitic scoliosis

OBJECTIVE

To identify what influence the various features of spinal deformity have on pulmonary function in persons with idiopathic and the postpoliomyelitic scoliosis.

DESIGN

Prospective, cohort, observational study with clinical and radiologic evaluations.

SETTING

Hospital-based rehabilitation units.

PATIENTS

Forty-four patients with idiopathic scoliotis and 16 with postpoliomyelitic scoliotis. Each group was divided into subgroups: normal and abnormal pulmonary function.

INTERVENTION

Clinical and radiologic evaluation of spinal deformity, full pulmonary functional test and respiratory muscle strength were performed. Presence of dyspnea on exertion and low back pain (LBP) was recorded.

MAIN OUTCOME MEASURES

Pulmonary function: spirometry, lung volume test, and diffusing capacity. Respiratory muscle strength: maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP). Presence of dyspnea on exertion (DOE), and LBP were also recorded. Characteristics of spinal deformity: direction of convexity, uppermost vertebra, number of involved vertebrae, Cobb angle, the apical vertebra, degree of rotation at the apical vertebra, type of scoliotic curve, and presence of balanced spine and pelvic obliquity. Chi-square analyses and Mann-Whitney U test for between-groups comparisons. Spearman's rho correlation coefficient to determine the existence and magnitude of a relationship.

RESULTS

We found significant differences between the idiopathic and postpoliomyelitis groups in the degree of rotation at the apical vertebra, MIP, average percentage of predicted vital capacity, residual volume/total lung capacity, presence of double or triple curves, pelvic obliquity, and DOE. Between the idiopathic scoliotis subgroups we found significant differences in the uppermost vertebra and number of vertebrae in the scoliotic curve. Between the subgroups of the postpoliomyelitis group were significant differences in the location of the apical vertebra and the uppermost vertebral body of scoliotic curve. In the idiopathic group, pulmonary function was mostly related to scoliotic angle, number of vertebrae in the scoliotic curve, location of the uppermost vertebra, and the patients' age; MIP and MEP were negatively related to the scoliotic angle and degree of rotation of apical vertebra. In the postpoliomyelitis group, pulmonary function was mostly related to scoliotic angle, kyphotic angle, location of the uppermost vertebra of the scoliotic curve, and age.

CONCLUSION

No single factor can predict the severity of impairment in scoliotic patients' pulmonary function. In both groups, severity of pulmonary impairment was related to the combined features of the spinal deformity. However, uppermost vertebra, scoliotic angle, and patient's age may play important roles influencing pulmonary function in both groups.

Hypokalemic muscular paralysis causing acute respiratory failure due to rhabdomyolysis with renal tubular acidosis in a chronic glue sniffer

CASE REPORT

A 34-year-old male was admitted to the emergency department with the development of quadriparesis and respiratory failure due to hypokalemia after prolonged glue sniffing. The patient was subsequently given mechanical ventilatory support for respiratory failure. He was weaned from the ventilator 4 days later after potassium replacement. Toluene is an aromatic hydrocarbon found in glues, cements, and solvents. It is known to be toxic to the nervous system, hematopoietic system, and causes acid-base and electrolyte disorders. Acute respiratory failure with hypokalemia and rhabdomyolysis with acute renal failure should be considered as potential events in a protracted glue sniffing.

Embryonic XMab21l2 expression is required for gastrulation and subsequent neural development

Cell fate determining gene mab-21 regulates the proper establishment of neural cell fate and sensory organ identity in nematode. Mammalian homologs of mab-21 have also been implicated to play critical roles in mid-, hindbrain and craniofacial differentiation. We report here the isolation of a mab-21 homolog, XMab21l2, from Xenopus. We showed that its expression in Xenopus was initiated at gastrulation and prominent signal was detected in neurulating embryos at the neural tube, the optic tissue, the developing midbrain, and the pharyngeal pouches. We demonstrated by RNA interference (RNAi), together with other antisense approaches, that XMab21l2 expression is required for the completion of gastrulation and subsequent neural development.

Arsenic trioxide induces apoptosis in human gastric cancer cells through up-regulation of p53 and activation of caspase-3

Arsenic trioxide (As(2)O(3)) can induce clinical remission in patients suffering from acute promyelocytic leukemia, through induction of apoptosis and activation of caspases. We investigated the potential use of As(2)O(3) in human gastric cancer and its possible mechanisms. Human gastric cancer cell lines AGS and MKN-28 were treated with various concentrations (0.1 to 100 microM) of As(2)O(3) for 24 to 72 hr. Apoptosis was determined by acridine orange staining, flow cytometry and DNA fragmentation. Protein levels of p53, p21(waf1/cip1), c-myc, bcl-2 and bax were detected by Western blotting. Effects of As(2)O(3) on caspase-3 protease activity, its protein concentration and cleavage of poly(ADP)-ribose polymerase (PARP) were also studied. As(2)O(3) inhibited cell growth and induced apoptosis in both cell lines, though AGS cells were more sensitive. As(2)O(3) induced apoptosis in AGS cells in a concentration- and time-dependent manner. Treatment resulted in a marked increase in p53 protein levels as early as 4 hr. Co-incubation with p53 anti-sense oligo-nucleotide suppressed As(2)O(3)-induced intracellular p53 over-expression and apoptosis. As(2)O(3) increased the activity of caspase-3, with appearance of its 17 kDa peptide fragment, and cleavage of PARP, with appearance of the 85 kDa cleavage product, both in parallel with the induction of apoptosis. Both the tripeptide caspase inhibitor zVAD-fmk and the specific caspase-3 inhibitor DEVD-fmk partially suppressed As(2)O(3)-induced caspase-3 activation and apoptosis. As(2)O(3) inhibits cell growth and induces apoptosis in gastric cancer cells, involving p53 over-expression and activation of caspase-3. The potential use of this compound in the treatment of gastric cancer is worth further investigation.

Arsenic trioxide induces apoptosis in human gastric cancer cells through up-regulation of p53 and activation of caspase-3

Arsenic trioxide (As(2)O(3)) can induce clinical remission in patients suffering from acute promyelocytic leukemia, through induction of apoptosis and activation of caspases. We investigated the potential use of As(2)O(3) in human gastric cancer and its possible mechanisms. Human gastric cancer cell lines AGS and MKN-28 were treated with various concentrations (0.1 to 100 microM) of As(2)O(3) for 24 to 72 hr. Apoptosis was determined by acridine orange staining, flow cytometry and DNA fragmentation. Protein levels of p53, p21(waf1/cip1), c-myc, bcl-2 and bax were detected by Western blotting. Effects of As(2)O(3) on caspase-3 protease activity, its protein concentration and cleavage of poly(ADP)-ribose polymerase (PARP) were also studied. As(2)O(3) inhibited cell growth and induced apoptosis in both cell lines, though AGS cells were more sensitive. As(2)O(3) induced apoptosis in AGS cells in a concentration- and time-dependent manner. Treatment resulted in a marked increase in p53 protein levels as early as 4 hr. Co-incubation with p53 anti-sense oligo-nucleotide suppressed As(2)O(3)-induced intracellular p53 over-expression and apoptosis. As(2)O(3) increased the activity of caspase-3, with appearance of its 17 kDa peptide fragment, and cleavage of PARP, with appearance of the 85 kDa cleavage product, both in parallel with the induction of apoptosis. Both the tripeptide caspase inhibitor zVAD-fmk and the specific caspase-3 inhibitor DEVD-fmk partially suppressed As(2)O(3)-induced caspase-3 activation and apoptosis. As(2)O(3) inhibits cell growth and induces apoptosis in gastric cancer cells, involving p53 over-expression and activation of caspase-3. The potential use of this compound in the treatment of gastric cancer is worth further investigation.

Energy expenditure of wheeling and walking during prosthetic rehabilitation in a woman with bilateral transfemoral amputations

OBJECTIVE

To compare the energy expenditure of locomotion by wheelchair with that required for prosthetic ambulation in a person with bilateral transfemoral (TF) amputations.

DESIGN

Observational, single patient, descriptive.

SETTING

An 80-meter long rectangular hallway in a rehabilitation unit.

PATIENT

A 41-year-old woman with bilateral TF amputations that were performed 79 days before her admission to the rehabilitation unit.

MAIN OUTCOME MEASURES

The oxygen uptake, oxygen cost, heart rate, speed, cadence, and stride length of walking measured during a 4-month course of prosthetic rehabilitation. Five locomotion conditions were evaluated: (1) wheelchair propulsion, (2) walking with short-leg prostheses (stubbies) and a walker, (3) long-leg prostheses and a walker, (4) long-leg prostheses without knee mechanism and axillary crutches, and (5) long-leg prostheses with right polycentric knee and left locked knee and axillary crutches. A portable and telemetric system was used to measure the metabolic parameters. An arm ergometry graded exercise test was performed at the end of rehabilitation.

RESULTS

Oxygen cost (range, 466%--707% of that of wheeling) and heart rate (range, 106%--116% of that of wheeling) were higher during walking with various combinations of prostheses and walking aids. The speed of prosthetic walking was only 24% to 33% of that of wheeling. Our patient preferred using a wheelchair to prosthetic walking after discharge.

CONCLUSIONS

People with bilateral TF amputations require very high cardiorespiratory endurance to fulfill the energy demand during prosthetic rehabilitation. The high energy cost of prosthetic walking will limit its application in daily activities.

Transcriptional regulation of the Drosophila gene zen by competing Smad and Brinker inputs

The establishment of expression domains of developmentally regulated genes depends on cues provided by different concentrations of transcriptional activators and repressors. Here we analyze the regulation of the Drosophila gene zen, which is a target of the Decapentaplegic (Dpp) signaling pathway during cellular blastoderm formation. We show that low levels of the Dpp signal transducer p-Mad (phosphorylated Mad), together with the recently discovered negative regulator Brinker (Brk), define the spatial limits of zen transcription in a broad dorsal-on/ventral-off domain. The subsequent refinement of this pattern to the dorsal-most cells, however, correlates with high levels of p-Mad that accumulate in the same region during late blastoderm. Examination of the zen regulatory sequences revealed the presence of multiple Mad and Brk binding sites, and our results indicate that a full occupancy of the Mad sites due to high concentrations of nuclear Mad is the primary mechanism for refinement of zen. Interestingly, several Mad and Brk binding sites overlap, and we show that Mad and Brk cannot bind simultaneously to such sites. We propose a model whereby competition between Mad and Brk determines spatially restricted domains of expression of Dpp target genes.

Improving operative safety for cirrhotic liver resection

BACKGROUND

Liver resection in a patient with cirrhosis carries increased risk. The purposes of this study were to review the results of cirrhotic liver resection in the past decade and to propose safe strategies for cirrhotic liver resection.

METHODS

Based on the date of operation, 359 cirrhotic liver resections in 329 patients were divided into two intervals: period 1, from September 1989 to December 1994, and period 2, from January 1995 to December 1999. The patient backgrounds, operative procedures and early postoperative results were compared between the two periods. The factors that influenced surgical morbidity were analysed.

RESULTS

In period 2, patient age was higher and the amounts of blood loss and blood transfused were lower. Although postoperative morbidity rates were similar, blood transfusion requirement, postoperative hospital stay and mortality rate were significantly reduced in period 2. No death occurred in 154 consecutive cirrhotic liver resections in the last 38 months of the study. Prothrombin activity and operative time were independent factors that influenced postoperative morbidity.

CONCLUSION

With improving perioperative assessment and operative techniques, most complications after cirrhotic liver resection can be treated with a low mortality rate. However, more care should be taken if prothrombin activity is low or there is a long operating time.

Arsenic trioxide induces apoptosis in human gastric cancer cells through up-regulation of p53 and activation of caspase-3

Arsenic trioxide (As(2)O(3)) can induce clinical remission in patients suffering from acute promyelocytic leukemia, through induction of apoptosis and activation of caspases. We investigated the potential use of As(2)O(3) in human gastric cancer and its possible mechanisms. Human gastric cancer cell lines AGS and MKN-28 were treated with various concentrations (0.1 to 100 microM) of As(2)O(3) for 24 to 72 hr. Apoptosis was determined by acridine orange staining, flow cytometry and DNA fragmentation. Protein levels of p53, p21(waf1/cip1), c-myc, bcl-2 and bax were detected by Western blotting. Effects of As(2)O(3) on caspase-3 protease activity, its protein concentration and cleavage of poly(ADP)-ribose polymerase (PARP) were also studied. As(2)O(3) inhibited cell growth and induced apoptosis in both cell lines, though AGS cells were more sensitive. As(2)O(3) induced apoptosis in AGS cells in a concentration- and time-dependent manner. Treatment resulted in a marked increase in p53 protein levels as early as 4 hr. Co-incubation with p53 anti-sense oligo-nucleotide suppressed As(2)O(3)-induced intracellular p53 over-expression and apoptosis. As(2)O(3) increased the activity of caspase-3, with appearance of its 17 kDa peptide fragment, and cleavage of PARP, with appearance of the 85 kDa cleavage product, both in parallel with the induction of apoptosis. Both the tripeptide caspase inhibitor zVAD-fmk and the specific caspase-3 inhibitor DEVD-fmk partially suppressed As(2)O(3)-induced caspase-3 activation and apoptosis. As(2)O(3) inhibits cell growth and induces apoptosis in gastric cancer cells, involving p53 over-expression and activation of caspase-3. The potential use of this compound in the treatment of gastric cancer is worth further investigation.

A simple modeling approach towards hydroperiod effects on fish dynamics in a northern Taiwan wetland ecosystem

In this paper we develop a simple dynamic model to describe the seasonality of fish population subjected to the pattern of water level fluctuations (i.e., hydroperiod) in a northern Taiwan wetland ecosystem, Kuandu Natural Reservation. We use a harmonic oscillation to characterize hydroperiod quantitatively by obtaining the amplitude and timing of the dominant periodic component in a time series of water levels. The model illustrates the temporal pattern of fish dynamics through the year that can result in very high density of fish at the end of a hydroperiod as well as the importance of ponds and other depressions that both are refuges and sinks during dry periods. We suggest that a 9-mon effective threshold in the length of the hydroperiod must be exceeded to produce high fish population densities. Our results also indicate that the large, piscivorous fish appear to have a major impact on smaller fish in the marsh habitat. Simulation results reveal that the recovery of small fish populations in the marsh following a major drought requires up to two years. The collective results imply that human activities such as drainage or other alterations of the hydrology can exacerbate natural cycles and results in detrimental stresses on fish production and the higher trophic levels dependent on this production.

Acute toxicity modeling of rainbow trout and silver sea bream exposed to waterborne metals

Of three proposed acute toxicity models, the uptake-depuration (UD) model, the time-integrated concentration (TIC) model, and the concentration-time (CT) model are derived and verified with acute toxicity data to estimate the internal residues of waterborne metals in fish as a function of a few constants and variables. The main factors are the exposure time, the external exposure concentration, the bioconcentration factor (BCF), and the depuration rate constant (k2). The UD model is based on the concept of residue levels at the cell membrane well correlating with the whole-body concentrations, whereas the TIC and the CT models are based on the idea of irreversible inhibition of the enzyme acetylcholinesterase (AChE) governing the metal acute toxicity in that metals in the entire fish or in the aqueous phase can be described by the critical area under the time-concentration curve that is associated with a critical TIC of toxicant in the target tissue. A highly significant correlation (r2 > 0.9) was found between predictions and LC50(t) data for both the TIC and the CT models, indicating successfully describe 4- to 18-d LC50(t) data of arsenic (As), cobalt (Co), copper (Cu), and Co/Cu mixture in rainbow trout (Oncorhyuchus mykiss) and of Cu in fingerlings and subadults of silver sea bream (Sparus sarba). The time-dependent lethal internal concentration at the site of action that causes 50% mortality is also predicted for a given compound and species. It concludes that the TIC and the CT models can be applied to regulate the acute toxicity and to estimate incipient LC50 values and internal residues of waterborne metals in fish.

Gastric intramucosal PCO2 and pH variability in ventilated critically ill patients

OBJECTIVE

Gastric intramucosal PCO2 (PiCO2) and pH (pHi) are currently used as indices of the adequacy of splanchnic perfusion and as end points to guide therapeutic intervention. However, little is known about their spontaneous variability over time. The present study was designed to define the magnitude of spontaneous variability of PiCO2 and pHi in sedated medical intensive care unit (ICU) patients using an automated recirculating air tonometer and to test whether high-level positive end-expiratory pressure (PEEP) or inverse inspiratory/expiratory (I:E) ratio ventilation resulted in a greater variability than low PEEP with conventional I:E ratio ventilation.

DESIGN

Prospective study.

SETTING

Medical ICU in a tertiary medical center.

PATIENTS

Twenty-three acute respiratory failure patients.

INTERVENTIONS

After being sedated, patients were randomized to undergo pressure control ventilation at the following three settings: A, high PEEP (15 cm H2O) with conventional I:E ratio (1:2), and B, low PEEP (5 cm H2O) with inverse I:E ratio (2:1) alternately, and then C, low PEEP (5 cm H2O) with conventional I:E ratio (1:2). Each ventilation setting period lasted 1 hr.

MEASUREMENTS AND MAIN RESULTS

The PiCO2 and pHi were measured at baseline (time 0), and at 15, 30, 45, and 60 mins thereafter. The corresponding coefficients of variation (CVs) of PiCO2 for overall pooled group and settings A, B, and C were 4.0%, 4.4%, 3.4%, and 4.2%, respectively. The corresponding CVs of pHi for overall pooled group and settings A, B, and C were 0.36%, 0.37%, 0.33%, and 0.4%, respectively. Analysis of variance showed no significant difference in the CVs of PiCO2 or pHi between the three settings. The 95% confidence interval is approximately +/-8% variability for PiCO2 and +/-0.7% variability for pHi.

CONCLUSIONS

In critically ill medical ICU patients with stable hemodynamics, the spontaneous variability of PiCO2 or pHi are not substantial. High PEEP (15 cm H2O) and inverse ratio ventilation (2:1), which does not change the cardiac output or hemodynamics, does not contribute to increased spontaneous variability in PiCO2 or pHi.

Congenital complete heart block

Congenital complete heart blocks (CCHB) are mostly related to the neonatal lupus syndrome. The purpose of this paper was to assess the clinical spectrum of CCHB in our hospital. Nine patients were retrospectively enrolled between 1994 and 1999. The birth history, electrocardiography, 24-hour Holter monitoring, pacemaker insertion and its complications, maternal disease, and maternal and infant autoantibody levels were studied. All nine cases were diagnosed prenatally. Hydrops fetalis was noted in five (55.6%). Six cases were live births and the other three were terminated. No anatomical heart defects were noted. Initial electrocardiography revealed the atrial rates ranged from 150 to 166 beats per minute. The minimal ventricular rates ranged from 46 to 80 beats per minute. VVI mode pacemakers were inserted through xyphoid approach in all live-birth infants. Complications were noted in three of them (50%). Antinuclear antibody and anti-SSA/Ro antibody were positive in all 8 mothers (100%). The anti-SSB/La antibody was positive in 6 of the eight mothers (75%). Five infants tested positive for anti-SSA/Ro antibody. None of the infants tested positive for anti-SSB/La antibody. In conclusion, all CCHBs in our series were associated with maternal autoantibodies. Because of high complication rate of permanent pacemaker insertion during the neonatal period, it should be restricted in certain conditions.