Sengstaken-Blakemore tube in critical upper gastrointestinal bleeding: Implications for aeromedical retrieval

Sengstaken–Blakemore tubes (SBTs) are rarely used in Australia, because of improved access to endoscopy and interventional radiology, as well as overall lower rate of variceal haemorrhage from improvements in primary prophylaxis. SBT's use is associated with significant rate of serious complications, such as oesophageal perforation, mucosal necrosis, aspiration pneumonia and respiratory compromise secondary to external compression of the trachea. As such, SBT is currently only recommended for use in life‐threatening variceal haemorrhage, where endoscopic, embolization and pharmacologic therapy have been unsuccessful or are unavailable. No data exist for its use in Australasia but one area that it could be indicated is for hemodynamically unstable patients in remote setting, where long transfer times often means delayed access to endoscopy. We present a case of SBT insertion in retrieval medicine and discuss placement in the management of an unstable upper gastrointestinal bleed, complicating factors such as lack of radiology to confirm balloon position, the impact of flight altitude on balloon pressures, the maintenance of traction in flight and logistics of long flight times across the state of Queensland. This is the first case report of SBT use in the Australian aeromedical environment. It is also the first one where SBT has been used for duodenal bleeding, although the source of bleeding was unknown prior to insertion.

Systematic Review and Meta-analysis: Optimal Salvage Therapy in Acute Severe Ulcerative Colitis

BACKGROUND

Infliximab is an effective salvage therapy in acute severe ulcerative colitis; however, the optimal dosing strategy is unknown. We performed a systematic review and meta-analysis to examine the impact of infliximab dosage and intensification on colectomy-free survival in acute severe ulcerative colitis.

METHODS

Studies reporting outcomes of hospitalized steroid-refractory acute severe ulcerative colitis treated with infliximab salvage were identified. Infliximab use was categorized by dose, dose number, and schedule. The primary outcome was colectomy-free survival at 3 months. Pooled proportions and odds ratios with 95% confidence intervals were reported.

RESULTS

Forty-one cohorts (n = 2158 cases) were included. Overall colectomy-free survival with infliximab salvage was 79.7% (95% confidence interval [CI], 75.48% to 83.6%) at 3 months and 69.8% (95% CI, 65.7% to 73.7%) at 12 months. Colectomy-free survival at 3 months was superior with 5-mg/kg multiple (≥2) doses compared with single-dose induction (odds ratio [OR], 4.24; 95% CI, 2.44 to 7.36; P < 0.001). However, dose intensification with either high-dose or accelerated strategies was not significantly different to 5-mg/kg standard induction at 3 months (OR, 0.70; 95% CI, 0.39 to 1.27; P = 0.24) despite being utilized in patients with a significantly higher mean C-reactive protein and lower albumin levels.

CONCLUSIONS

In acute severe ulcerative colitis, multiple 5-mg/kg infliximab doses are superior to single-dose salvage. Dose-intensified induction outcomes were not significantly different compared to standard induction and were more often used in patients with increased disease severity, which may have confounded the results. This meta-analysis highlights the marked variability in the management of infliximab salvage therapy and the need for further studies to determine the optimal dose strategy.

Clinical Parameters Correlate With Endoscopic Activity of Ulcerative Colitis: A Systematic Review

BACKGROUND & AIMS

Optimal management of patients with ulcerative colitis (UC) requires assessment of disease activity-usually by endoscopy, which is invasive, costly, and not risk free. We performed a systematic review to determine whether clinical symptoms correlate with findings from endoscopy assessments of patients with UC.

METHODS

We performed a systematic review of publication databases from January 1980 through July 2018 to identify clinical trials and observational studies reporting correlations among symptoms, disease activity index scores and/or patient reported outcomes (rectal bleeding and/or stool frequency), and endoscopic disease activity. Correlations were ascertained in patients with active vs inactive disease and by disease extent and treatment type. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Because of significant heterogeneity, meta-analysis was not possible. Results were synthesized qualitatively and systematically.

RESULTS

Our final analysis included 23 studies (1 randomized trial, 22 observational studies) comprising 3320 patients with UC. The studies used a variety of measures to assess clinical activity, endoscopic activity, and measures of correlation (sensitivity, specificity, correlation coefficients, area under the receiver operator curve). Overall, studies were at moderate-high risk of bias. Composite clinical measures, including rectal bleeding and stool frequency, had moderate to strong correlations with endoscopic disease activity; the absence of rectal bleeding identified patients with inactive disease with higher levels of sensitivity than normalization of stool frequency. In general, symptoms correlated more strongly with endoscopic activity in patients with left-sided colitis than extensive colitis. The effect of different medications on the correlation between clinical and endoscopic activity has not been well studied.

CONCLUSIONS

In a systematic review, we found a moderate to strong correlation between clinical activity, particularly the combination of rectal bleeding and stool frequency, and endoscopic activity in patients with UC. Although these clinical assessments could help prioritize patients for endoscopic evaluation in resource-limited settings, challenges associated with treating patients based on symptoms alone preclude adaptation of current management algorithms.

Management of Paediatric Patients With Medically Refractory Crohn's Disease Using Ustekinumab: A Multi-Centred Cohort Study

BACKGROUND

Ustekinumab [UST] is effective in the treatment of adults with moderate to severe Crohn's disease [CD]. There is a paucity of data on its use in children.

AIM

To evaluate the response to UST in children with moderate to severe CD.

METHODS

This multicentre retrospective cohort study identified children under 18 years old with CD, who received open-labelled subcutaneous UST. The primary outcome was changes in mean abbreviated Paediatric Crohn's Disease Activity Index [aPCDAI] between baseline and 3 and 12 months, and rate of clinical remission at 3 and 12 months. Secondary outcomes were clinical response at the same time points, changes in C-reactive protein [CRP] and albumin, improvement in growth parameters, and rate of adverse events.

RESULTS

A total of 44 patients who failed at least one biological treatment were identified. Linear mixed model [LMM] analysis revealed a statistically significant effect of UST (χ2[1] = 42.7, p = 1.2 × 10-8) which lowered the aPCDAI scores by about 16 ± 2.7 at 3 months, and 19.6 ± 2.9 at 12 months. At 12 months, 38.6% of the patients achieved clinical remission and 47.8% achieved clinical response. There was a significant increase in mean weight z-score of 0.48 [±0.13] [p <0.001] and in mean body mass index [BMI] z score of 0.66 [±0.16] [p <0.001]. The probability of remaining on UST at 12 months was 76.9%. The rate of adverse events was 12.4 per 1000 patient-months.

CONCLUSIONS

Subcutaneous UST should be considered a viable therapeutic option for paediatric patients who are refractory to other biological agents. Prospective randomised trials are needed.

High-Dose Infliximab Rescue Therapy for Hospitalized Acute Severe Ulcerative Colitis Does Not Improve Colectomy-Free Survival

BACKGROUND AND OBJECTIVE

Optimization strategies with infliximab (IFX) are increasingly used as rescue therapy for steroid refractory acute severe ulcerative colitis (ASUC). We aim to determine if intensified IFX induction improves colectomy rate and identifies outcome predictors.

METHODS

Hospitalized adult patients who received IFX for ASUC between 2010 and 2016 were identified. We compared standard inductions (5 mg/kg) vs high-dose induction (10 mg/kg) with 3-month colectomy rate as primary outcome.

RESULTS

Seventy-two patients (62.5% male, median age 38.5) were identified. Thirty-seven patients (51.3%) received 5 mg/kg IFX and 35 received 10 mg/kg. Baseline clinical, biochemical and endoscopic parameters were well matched between these two groups. 10 mg/kg was more likely to be used by clinicians from 2014 onwards (p < 0.001). Three-month colectomy rate was 9.7%; which was not significantly different between the standard (5.4%) and high-dose (14.3%) IFX induction (p = 0.205). CRP ≥ 60 (OR 10.9 [95% CI 1.23-96.50], p = 0.032), hemoglobin ≤ 90 g/L (OR 15.6 [95% CI 2.61-92.66], p = 0.036) and albumin < 30 g/L (OR 9.4 [95% CI 1.06-83.13], p = 0.044) were associated with increased risk of colectomy at 3 months in univariate regression analysis.

CONCLUSION

Use of high-dose infliximab rescue therapy did not improve 3-month colectomy-free survival in this cohort. Tailored use in high-risk patients may be beneficial although further validation is required.

Maladaptive coping, low self-efficacy and disease activity are associated with poorer patient-reported outcomes in inflammatory bowel disease

BACKGROUND/AIMS

Patient-reported outcomes (PRO) are key aspects in the management of inflammatory bowel disease (IBD). This study aims to evaluate factors associated with adverse PRO, including modifiable social constructs of maladaptive coping and self-efficacy as well as physician-patient concordance on PRO.

PATIENTS AND METHODS

This cross-sectional study was performed in patients with Crohn's disease (CD) or ulcerative colitis (UC) from September 2015 to March 2016. Validated questionnaires were used to assess quality of life (Short IBD Questionnaire), disability (IBD disability index), productivity (work productivity and activity impairment questionnaire), anxiety/depression (Hospital Anxiety and Depression Scale), coping strategies [Brief Coping Operations Preference Enquiry (Brief COPE)], and self-efficacy (General Self-Efficacy Scale). Independent physician assessment was used to compare concordance with patients.

RESULTS

In all, 207 (CD: 144 and UC: 63) patients, with median age of 39 years, were included, with 42.5% males. Significant proportion of patients reported moderate/severe impairment of disability (30.5%), quality of life (29.4%), productivity (52.4%), anxiety (32.9%) and depression (23.3%). Disease activity and maladaptive coping were independently associated with unfavourable PRO, whereas self-efficacy had a positive effect in multivariate analysis. Physicians could accurately identify the magnitude of PRO impairment in standard clinical settings (r = 0.59-0.65, P < 0.001).

CONCLUSION

Disease activity and modifiable psychological constructs are associated with unfavorable PRO in patients with IBD. These factors could assist with identifying high-risk patients, many of whom may benefit from targeted interventions to improve health outcomes.

Screening for Nonalcoholic Fatty Liver Disease in Inflammatory Bowel Diseases: A Cohort Study Using Transient Elastography

BACKGROUND

Inflammatory bowel disease (IBD) patients may be at risk for nonalcoholic fatty liver disease (NAFLD) due to chronic inflammation, hepatotoxic drugs, and alteration of the gut microbiota. Prospective data using accurate diagnostic methods are lacking.

METHODS

We prospectively investigated prevalence and predictors of NAFLD and liver fibrosis by transient elastography (TE) with associated controlled attenuation parameter (CAP) in IBD patients as part of a routine screening program. NAFLD was defined as CAP ≥248 dB/m. Significant liver fibrosis (stage 2 or higher out of 4) was defined as TE measurement ≥7.0 kPa. Predictors of NAFLD and significant liver fibrosis were determined by logistic regression analysis.

RESULTS

A total of 384 patients (mean age 42.4 years, 45.0% male, 64.6% with Crohn's disease) with no significant alcohol intake were included. Prevalence of NAFLD and significant liver fibrosis was 32.8% and 12.2%, respectively. Independent predictors of NAFLD were older age (adjusted odds ratio [aOR], 1.45; 95% confidence interval [CI], 1.15-1.82), higher body mass index (BMI; aOR, 1.31; 95% CI, 1.20-1.42) and higher triglycerides (aOR, 1.45; 95% CI, 1.01-2.09). Significant liver fibrosis was independently predicted by older age (aOR, 1.38; 95% CI, 1.12-1.64) and higher BMI (aOR, 1.14; 95% CI, 1.07-1.23). Extrahepatic diseases were more common in IBD patients with NAFLD compared with those without, namely chronic kidney disease (10.3 vs 2.3%; P < 0.001) and cardiovascular diseases (11.3 vs 4.7%; P = 0.02).

CONCLUSIONS

NAFLD diagnosed by TE with CAP is a frequent comorbidity in IBD patients and is associated with extrahepatic diseases. Noninvasive screening strategies could help early diagnosis and initiation of interventions, including weight loss, correction of dyslipidemia, and linkage to care. 10.1093/ibd/izy200_video1izy200.video15794817619001.

Therapeutic Drug Monitoring Guides the Management of Crohn's Patients with Secondary Loss of Response to Adalimumab

BACKGROUND

Managing loss of response (LOR) in Crohn's disase (CD) patients remains challenging. Compelling evidence supports therapeutic drug monitoring (TDM) to guide management in patients on infliximab, but data for other biologics are less robust. We aimed to asses if empiric dose escalation led to improved clinical outcome in addition to TDM-guided optimization in CD patients with LOR to adalimumab (ADA).

METHODS

Retrospective chart review of patients followed between 2014 and 2016 at McGill IBD Center with index TDM for LOR to ADA was performed. Primary outcomes were composite remission at 3, 6, and 12 months in those with empiric adjustments versus TDM-guided optimization.

RESULTS

There were 104 patients (54.8% men) who were included in the study. Of this group, 81 patients (77.9%) had serum level (SL) ≥5µg/ml at index TDM with a median value of 12µg/ml (IQR 6.1-16.5). There were 10 patients (9.6%) who had undetectable SL with high anti-ADA antibodies and 48 (46.2%) received empiric escalation. TDM led to change in treatment in 58 patients (55.8%). Among them, 28 (48.3%) had discontinued ADA, 12 (21.7%) had addition of immunomodulator or steroid, and 18 (31%) had ADA dose escalation. Empiric dose escalation before TDM-based optimization was not associated with improved outcomes at 3, 6, and 12 months, irrespective of SL levels. Clear SL cutoff associated with composite remission was not identified.

CONCLUSIONS

Our data do not support empiric dose adjustment beyond that based on the result of the TDM in patients with LOR to ADA. TDM limits unnecessary dose escalation and provides appropriate treatment strategy without compromising clinical outcomes. 10.1093/ibd/izy044_video1izy044.video15768828880001.

Co-existence of non-alcoholic fatty liver disease and inflammatory bowel disease: A review article

Emerging data have highlighted the co-existence of non-alcoholic fatty liver disease (NAFLD) and inflammatory bowel disease; both of which are increasingly prevalent disorders with significant complications and impact on future health burden. Cross-section observational studies have shown widely variable prevalence rates of co-existing disease, largely due to differences in disease definition and diagnostic tools utilised in the studies. Age, obesity, insulin resistance and other metabolic conditions are common risks factors in observational studies. However, other studies have also suggested a more dominant role of inflammatory bowel disease related factors such as disease activity, duration, steroid use and prior surgical intervention, in the development of NAFLD. This suggests a potentially more complex pathogenesis and relationship between the two diseases which may be contributed by factors including altered intestinal permeability, gut dysbiosis and chronic inflammatory response. Commonly used immunomodulation agents pose potential hepatic toxicity, however no definitive evidence exist linking them to the development of hepatic steatosis, nor are there any data on the impact of therapy and prognosis in patient with co-existent diseases. Further studies are required to assess the impact and establish appropriate screening and management strategies in order to allow early identification, intervention and improve patient outcomes.

Lead distribution in blood and organs of mice exposed to lead by vein injection

To study lead (Pb) distribution in organs and blood in the case of Pb poisoning, mice were firstly exposed to Pb as 0.1 mL or 0.2 mL of lead nitrate solution (0.1 mg/mL) by vein injection every other day. Then, after metabolic absorption, the Pb level in the blood and organs of the mice was measured using flame atomic absorption spectrometry. The resulting data showed that 93% of Pb in blood was accumulated in red cells, but this percentage slightly decreased with increasing exposure time and injection volume. For other target organs, the highest Pb level was in the kidney, followed by the liver, spleen, heart and lung, and was lowest in the brain. Moreover, the Pb level in the heart and brain is in a growth trend at all times for 0.1 mL and 0.2 mL of Pb injection exposure in 15 days, while the growth trend of Pb in other target organs become slow for 0.2 mL of injection after exposure Pb 11 days.

Numerical and experimental study of velocity and temperature characteristics in a ventilated enclosure with underfloor ventilation systems

Airflow and temperature distributions in an enclosure with heat sources ventilated by floor supply jets with floor or ceiling air exit vents were investigated using experimental and numerical approaches. These ventilation configurations represent the floor return or the top return underfloor ventilation systems found in real applications. Experiments and numerical simulations were performed on a full-sized environmental chamber. The results reveal that the temperature stratification in the enclosure highly depended on the thermal length scale of the floor supply jets. When the thermal length scale of the supply jet was >>1, temperature stratification was minor for all tested heat densities and air distribution methods. Significant vertical temperature gradients occurred when the jet thermal length scale was <<1. Changes in air distribution methods also became significant for temperature stratification at small supply jet thermal length scales. Temperature stratification also affected the terminal height of the momentum-dominant region of the vertical buoyant supply jets. The applicability of these results to underfloor ventilation design was also discussed.

PRACTICAL IMPLICATIONS

In designing underfloor ventilation systems, supply jet conditions and heat load density have to be considered to avoid thermal discomfort because of excessive temperature stratifications. This study demonstrated, by both numerical simulations and experiments, that thermal length scale can be used as a design indicator to predict thermal stratifications under a floor return and a top return underfloor ventilation setting.

Experimental study of ventilation performance and contaminant distribution of underfloor ventilation systems vs. traditional ceiling-based ventilation system

Ventilation performance and pollutant distribution in a traditional ceiling-type ventilation system, a top-return (TR)-type and a floor-return (FR)-type underfloor ventilation systems were performed in a controlled experimental room. Tracer gas method was utilized to determine the age of air and the contaminant removal effectiveness. Tobacco smoke was also introduced to study the particle-phase pollutant distribution. The TR system delivered conditioned air more efficiently in the occupied zone and exhibited higher gaseous contaminant removal effectiveness. It also showed the lowest smoke particle concentration compared with the other two systems. The FR system showed better ventilation performance over the mixing system at the space that was close to the floor supply outlet and at the lower height level. The FR system was less effective than the TR system in removing buoyant tobacco smoke particles at the upper part of the room indicating its highly localized characteristics. Differences in experimental conditions between the present and the previous studies and their effects on the experimental results are discussed. In general, the experimental data suggested that both types of the underfloor ventilation systems have the potential of improving air quality at the breathing zone over the ceiling-based mixing system with suitable designs.

PRACTICAL IMPLICATIONS

This study shows the possibility of improving indoor air quality using underfloor ventilation systems compared with the traditional ceiling-based ventilation system. However, different configurations of the underfloor ventilation system show various ventilation characteristics. The engineers should consider these features when implementing an underfloor ventilation design. The top-return (TR) configuration improves indoor air quality by creating a displacement-like flow pattern while the floor-return (FR) configuration shows highly localized ventilation characteristics. The FR configuration improved the indoor air quality at spaces near the floor diffusers and up to certain heights.

Unusual thickness-dependent heat-capacity anomalies in free-standing hexatic liquid-crystal films

High-resolution heat-capacity and optical-reflectivity measurements have been conducted near the smectic-A to hexatic-B transition in thin free-standing films of the liquid-crystal compound 64COOBC. We find an unexpected dependence on film thickness of the integrated magnitude of the heat-capacity anomalies as the films undergo layer-by-layer transitions. We measure the penetration depths of the ordering from the surface and next-to-surface layers which are pertinent to the highly correlated thermal behavior.

Oxidized frying oil up-regulates hepatic acyl-CoA oxidase and cytochrome P450 4 A1 genes in rats and activates PPARalpha

Oxidized LDL (oxLDL) and its component hydroxy fatty acids were shown to activate peroxisome proliferator-activating receptor alpha (PPARalpha) and gamma (PPARgamma). To test the hypothesis that lipid oxidation products in oxidized frying oil (OFO) can activate PPARalpha and up-regulate its target genes, a feeding experiment and a transactivation experiment were conducted. Based on a 2 x 2 factorial design, four groups of Sprague-Dawley male weanling rats were fed diets containing either high (20 g/100 g, HO and HF) or low (5 g/100 g, LO and LF) levels of oxidized frying soybean oil (HO and LO) or fresh soybean oil (HF and LF) for 6 wk. The OFO sample was prepared by frying wheat dough sheets in soybean oil at 205 +/- 5 degrees C for 24 h. OFO dose dependently and significantly increased (P < 0.05) mRNA of acyl-CoA oxidase (ACO) and cytochrome P(450) 4A1(CYP4A1) in liver of rats. Dietary OFO also dose dependently increased liver microsomal CYP4A protein (P < 0.05). The activity of hepatic ACO of the HO group was sixfold that of the HF group (P < 0.05). Plasma total lipids, liver triglycerides, cholesterol and total lipids were reduced in rats fed the LO and HO diets (P < 0.05). Through the ligand binding domain of PPARalpha, the hydrolyzed OFO enhanced the expression of alkaline phosphatase (ALP) reporter gene to a significantly greater extent (P < 0.05) than the hydrolyzed fresh soybean oil in a transactivation assay using a clone of CHO K1 cells stably expressing Gal4-PPARalpha chimeric receptor and UAS4-ALP reporter. The results support our hypothesis that dietary OFO, by activating PPARalpha, up-regulates the expression of PPARalpha downstream genes and alters lipid metabolism in rats.

Direct layer-by-layer freezing of a smectic liquid-crystal surface into the crystalline phase

Electron diffraction and optical reflectivity have provided the direct confirmation of the existence of layer-by-layer surface transitions from the smectic-A immediately to the crystal-B phase in a liquid-crystal material, without going through an intermediate hexatic phase. The molecular interactions are found to be through retarded van der Waals forces. Our results suggest that a smectic-A film can transform into a crystal-B through three possible scenarios.

Unusual thickness-dependent thermal behavior and anticlinic coupling in chiral smectic free-standing liquid-crystal films

We observe, in free-standing films of a chiral smectic liquid crystal, a series of discrete transitions in the relative orientation of the tilt of the interior and surface layers. These transitions include a remarkable reentrant synclinic-anticlinic-synclinic ordering sequence of the film surfaces in the presence of an electric field upon cooling. The profiles of the associated heat-capacity anomalies are found to be strongly thickness dependent and exhibit a novel crossover behavior in reduced dimensions. We measure the anticlinic coupling between tilted surface layers in the smectic- A phase.

Pentoxifylline synergizes with all-trans retinoic acid to induce differentiation of HL-60 myelocytic cells, but suppresses tRA-augmented clonal growth of normal CFU-GM

All-trans retinoic acid (tRA) has been shown to promote terminal differentiation of promyelocytic leukemia cells, but frequently induce hyperleukocytosis and pulmonary leakage syndrome. Employing pentoxifylline (PTX), a phosphodiesterase inhibitor which could raise intracellular cAMP and modulate leukocyte activation, we sought to investigate if PTX could enhance tRA-induced promyelocytic leukemic cell differentiation but suppress tRA-augmented growth and activation of human granulocytes. tRA could significantly suppress clonal growth of U937 and HL-60 leukemic cells but enhanced the CFU-GM formation of normal bone marrow cells (22 +/- 6 vs. 90 +/- 16 CFU/well). PTX significantly augmented tRA suppression of clonal growth of U937 and HL-60 leukemic cells but suppressed tRA-augmented CFU-GM formation of normal bone marrow cells (90 +/- 16 vs. 25 +/- 9 CFU/well). In addition, PTX enhanced tRA-induced growth inhibition and differentiation of promyelocytic HL-60 leukemic cells, but suppressed respiratory burst activation by the immature granulocytic HL-60 cells and suppressed CD11b adhesion molecule expression by mature granulocytes. PTX similar to dibutyric cAMP promoted HL-60 myelocytic leukemic cell differentiation and growth inhibition, whereas PTX, in contrast to dibutyric cAMP which could augment phorbol myristate acetate (PMA)-elicited respiratory burst activity by immature granulocytes, suppressed the PMA-elicited respiratory burst activity by immature and mature granulocytes. PTX did not raise the intracellular cAMP level of HL-60 cells, but partly suppressed the dibutyric cAMP-elicited elevation of intracellular cAMP level. Results from these studies suggest that PTX might act through different signaling pathways to enhance tRA-induced myelocytic leukemic cell differentiation but prevent from hyperreactive normal granulopoiesis and granulocyte activation.

The influence of heavy metals on partitioning of PAHs during incineration

The presence of heavy metals (Cr, Cd, Pb and Zn) in feedstock increases the partitioning of polycyclic aromatic hydrocarbons (PAHs) in the solid as well as in the gaseous phases, which has been reported in our previous study. However, the partitioning of PAHs in air-pollution control equipment (APCE) has not been investigated thus far. Hence, the present work was conducted to study the partitioning of PAHs in APCE and the effect of heavy metals on PAHs formation by varying the target heavy metals in the feedstock.A fluidized bed incineration system which includes a primary combustion chamber (sand bed), a secondary combustion chamber (freeboard), and an APCE (cyclone and scrubber) was utilized in this study. The feedstock that contained various heavy metals was fed into the incinerator, and then the PAHs in the cyclone and scrubber were analyzed to determine the effect of heavy metals on PAHs partitioning. The results indicate that the presence of Pb and Zn in feedstock facilitates the formation of PAHs.

Structural characterization of surface hexatic behavior in free-standing 4O.8 liquid-crystal films

Electron diffraction in free-standing liquid-crystal films of N-(4-n-butoxybenzylidene)-4-n-octylaniline between 3 and 12 molecular layers thick reveals the unusual occurrence of the smectic-A' phase, a highly correlated isotropic liquid, on the surface of smectic-A films. The surface smectic-A-smectic-A' transition is found to be first order. Surprisingly, the temperature range of the subsequent surface hexatic-B phase is reduced with decreasing film thickness.

Crystalline transitions in free-standing films of 4-n-heptyloxybenzylidene-4-n-heptylaniline

Free-standing films of 4-n-heptyloxybenzylidene-4-n-heptylaniline are known to exhibit multiple smectic-I surface layers in the presence of a smectic-A interior. The phase transitions leading to the crystallization of these films have been studied using electron diffraction. Our data are consistent with the scenario of the smectic-I surface layers first developing a crystal-B outermost layer before transforming entirely into the crystal-B phase, to be followed by the freezing of the smectic-A interior. The adjacent crystal-B and smectic-I layers show evidence of orientational epitaxy.

Effects of parenteral infusion with fish-oil or safflower-oil emulsion on hepatic lipids, plasma amino acids, and inflammatory mediators in septic rats

This study was designed to investigate the effects of preinfusion with total parenteral nutrition (TPN) using fish-oil (FO) versus safflower-oil (SO) emulsion as fat sources on hepatic lipids, plasma amino-acid profiles, and inflammatory-related mediators in septic rats. Normal rats, with internal jugular catheters, were assigned to two different groups and received TPN. TPN provided 300 kcal. kg(-1). d(-1), with 40% of the non-protein energy as fat. All TPN solutions were isonitrogenous and identical in nutrient composition except for the fat emulsion, which was made of SO or FO. After receiving TPN for 6 d, each group of rats was further divided into control and sepsis subgroups. Sepsis was induced by cecal ligation and puncture; control rats received sham operation. All rats were classified into four groups as follows: FO control group (FOC; n = 7), FO sepsis group (FOS; n = 8), SO control group (SOC; n = 8), and SO sepsis group (SOS; n = 9). The results of the study demonstrated that plasma concentrations of triacylglycerol and non-esterified fatty acids did not differ between the FO and SO groups, regardless of whether the animals were septic. SOS had significantly higher total lipids and cholesterol content in the liver than did the SOC group. The FOS group, however, showed no difference from the FOC group. Plasma leucine and isoleucine levels were significantly lower in the SOS group than in the SOC group, whereas no difference in these two amino acids was observed between the FOC and FOS groups. Plasma arginine levels were significantly lower in both septic groups than in the groups without sepsis when either FO or SO was infused. Plasma glutamine levels, however, did not differ across groups. No differences in interleukin-1beta, interleukin-6, tumor necrosis factor-alpha, or leukotriene B(4) concentrations in peritoneal lavage fluid were observed between the two septic groups. These results suggest that catabolic reaction in septic rats preinfused with FO is not as obvious as those preinfused with SO. Compared with SO emulsion, TPN with FO emulsion prevents liver fat accumulation associated with sepsis. However, parenterally administered FO had no beneficial effect in lowering cytokines and LTB(4) levels in peritoneal lavage fluid in septic rats induced by cecal ligation and puncture.

Study of indoor radon levels in high-rise air-conditioned office buildings

A series of measurements were conducted to study the indoor radon pollution in air-conditioned high-rise office buildings. Continuous monitoring of indoor radon levels in nine air-conditioned premises located in six office buildings in Hong Kong was conducted from August 1996 to February 1998. Each of the tests lasted for at least 48 hours. The measurement covered both day time monitoring while the air-conditioning was on and night time monitoring while the air-conditioning was off. The indoor radon level followed inversely the operation pattern of the mechanical ventilation systems in the buildings. During office hours when the mechanical ventilation was on, the indoor radon level decayed and after the mechanical ventilation was off during non-office hours, the radon level increased. The average indoor radon level during office hours on the nine premises varied from 87 Bq/m3 to 296 Bq/m3, and the indoor averaged radon levels over both day time and night time periods without mechanical ventilation were about 25 percent higher. The air infiltration rate and the radon emission characteristics from the building materials were estimated from the radon build-up curves which were observed after the mechanical ventilation was off. The radon decay curve observed after the mechanical ventilation system was turned on was used to calculate the total fresh air intake rate. Average radon emanation rates of the building materials in the six buildings varied from 0.0019 to 0.0033 Bq/m2s. It has been found that building infiltration rate accounted for about 10-30 percent of the total building ventilation rate in the buildings depending on building tightness.

Radon emanation of building material--impact of back diffusion and difference between one-dimensional and three-dimensional tests

Small-scale chamber experiments were conducted to investigate the radon emanation rates of commonly used building materials such as bare concrete, granite, red brick, and sand brick. It has been found that back diffusion caused by the accumulation of radon in the indoor environment has significant influence on the radon emanation rate. The radon emanation rate can be expressed as the summation of an initial emanation rate and the product of a specific back diffusion coefficient and the indoor radon level. In some occasions the radon emanation rate can be significantly lower than its initial value. A database was developed summarizing results from 26 samples. The influence of relative humidity on the radon emanation characteristics has also been discussed. Separate tests were done by coating the four sides of the building material with silicone gel to simulate a one-dimensional radon diffusion geometry. The results show that a factor has to be included when the three-dimensional test results are used to describe one-dimensional geometry, such as radon emanation from building wall surfaces.

The relationship between the quantity of heavy metal and PAHs in fly ash

Heavy metal and polycyclic aromatic hydrocarbons (PAHs) in flue gas have received considerable attention in recent years due to their mutagenic or carcinogenic properties. The present study is carried out to investigate the influence of the quantity of heavy metals on PAHs formation in fly ash. A fluidized bed incinerator was used in this experiment to obtain fly ash of chemical similarity by incinerating various compositions of waste. The obtained fly ash, both with and without heavy metal, were used to adsorb the PAHs in the flue gas and to investigate the formation of PAHs in fly ash. The results indicate that carbon and heavy metals most greatly influence the formation of PAHs in the fly ash. Carbon is absorptive; heavy metals encourage not only absorption of PAHs but also catalyze PAHs formation.

Immunohistochemical study of monoclonal antibody MGD-1 in gastric carcinoma

This paper reports a pathological and immunohistochemical study of gastric carcinoma for immunoreactivity with a monoclonal antibody. MGD-1, raised against cells from an adenocarcinoma of stomach. Fifty-four of 61 gastric carcinomas (89%) were positive for MGD-1. Metastatic gastric carcinoma in local nodes was positive in all 11 such cases. Out of 40 examples of chronic atrophic gastritis, only three, with mild dysplasia, were positive (7.5%). Forty cases with normal gastric mucosa were negative. The MGD-1 detection-rate of well- and poorly-differentiated gastric carcinoma was 85% and 93% respectively. The metastatic cells and cells infiltrating the submucosa and muscular layer were more frequently positive and showed stronger staining with MGD-1 than those in mucosa. These results show that MGD-1 possesses a high degree of specificity for gastric carcinoma and could be used diagnostically.

Cytochemical studies of callus development from microspore in cultured anther of rice

Cytochemical studies of androgenic anthers of Oryza sativa picked from the culture at 2 day intervals from 0 to 40 days have been carried out. Glutaradehyde-OsO4-fixed and plastic-embedded sections were stained with TBO, SBB and PAS for acidic polymers, lipids and polysaccharides respectively. Among the population only 4% of microspores, which accumulate abundant amorphous lipid in the first few days of culture, are androgenic. Less than 30%, which have many lipid granules and some amorphous lipid, become nutritive microspores. Starch grains also accumulate in these nutritive microspores which degenerate at the stage when the androgenic multicellular microspores are in rapid development. The remaining microspores, which have no or little lipid, degenerate early. At about the 100-cell stage, each multicellular unit consists of two cell types, large and small. The large cells contain abundant amorphous lipid and starch grains which the small ones stain intensely with TBO.Our results indicate that the epidermis and endothecium of the cultured anthers are not quiescent. They can accumulate and transport lipid and polysaccharides at certain stages during the cultural period. Globular embryoid appearing structures and leaf-like protrusions can be observed at the surface of the callus in about 40-day old culture, indicating that both embryogenesis and organogenesis may take place in rice callus.

Effects of ginsenosides Rg1 and Rb1 of Panax ginseng on mitosis in root tip cells of Allium cepa

The effects of ginsenosides Rg1 and Rb1 of Panax ginseng on mitosis in the onion root tip cells as well as on the rate of DNA synthesis in onion seedlings were studied. Results obtained from the concentration and time course study in bulb and seeding root tip cells indicate that Rg1 promotes and Rb1 inhibits mitosis, both being dose-dependent. The promoting effect of Rg1 on the rate of DNA synthesis was observed at the peak hour which occurs at the same time as that of the control. Rb1 was found to shift the peak hour of DNA synthesis to a later period of the experiment. These results are in agreement with the results obtained from the study of the cell cycle by pulse labeling and autoradiography, which show that Rg1 shortens the mitotic cell cycle and S period while Rb1 lengthens them. They in turn increase and decrease the mitotic indices respectively.

Effects of ginsenoside Rg1 of Panax ginseng on mitosis in human blood lymphocytes in vitro

The ginsenoside Rg1 extracted from the root of Panax ginseng can promote mitosis in cultured human lymphocytes activated by PHA or Con A. Its most effective concentrations are around 0.0003-0.0005 mg per ml of medium. Experiments show that it does not arrest the cells at any particular mitotic stage. It can also enhance the DNA synthesis in the activated lymphocytes. As a result of the increased number of the mitotic cells and enhanced DNA synthesis, the cell density is significantly increased in the Rg1-treated culture as compared with the control. However, in the absence of a mitogenic lectin Rg1 cannot restart the quinescent human lymphocytes to divide in vitro; therefore it is not mitogenic to resting cells. The possible action of Rg1 on activated human lymphocytes as well as its pharmacological significance are discussed.