Antacids for preventing oesophagogastric variceal bleeding and rebleeding in cirrhotic patients

BACKGROUND

Ruptured gastroesophageal varices are the most severe and frequent cause of gastrointestinal bleeding in cirrhotic patients, leading to death in 5% to 8% of patients during the first 48 hours and oesophagogastric varices account for 60% to 80% of first bleeding in patients with portal hypertension. Antacids are often used for emergency treatment of bleeding oesophageal varices in patients with cirrhosis of the liver.

OBJECTIVES

To evaluate the beneficial and harmful effects of antacids for preventing oesophagogastric bleeding and rebleeding.

SEARCH STRATEGY

We identified relevant randomised clinical trials by searching The Cochrane Hepato-Biliary Group Controlled Trials Register (June 2007), the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 2, 2007), MEDLINE (1950 to June 2007), EMBASE (Excerpta Medica Database) (1980 to June 2007), and the Science Citation Index Expanded (SCI-EXPANDED) (1945 to June 2007). Additional randomised trials were sought from the reference lists of the trials found and reviews identified by the electronic searches.

SELECTION CRITERIA

We planned to include randomised clinical trials.

DATA COLLECTION AND ANALYSIS

We planned to summarise data using Cochrane Collaboration methodologies.

MAIN RESULTS

We could not find any randomised clinical trials on antacids for preventing oesophagogastric variceal bleeding and bleeding in cirrhotic patients.

AUTHORS' CONCLUSIONS

it is not possible to determine whether antacids are beneficially effective or harmful for preventing oesophagogastric variceal bleeding and rebleeding in cirrhotic patients since randomised clinical trials investigating it are lacking.

Modeling repeated time-to-event health conditions with discontinuous risk intervals. An example of a longitudinal study of functional disability among older persons

OBJECTIVES

Researchers have often used rather simple approaches to analyze repeated time-to-event health conditions that either examine time to the first event or treat multiple events as independent. More sophisticated models have been developed, although previous applications have focused largely on such outcomes having continuous risk intervals. Limitations of applying these models include their difficulty in implementation without careful attention to forming the data structures.

METHODS

We first review time-to-event models for repeated events that are extensions of the Cox model and frailty models. Next, we develop a way to efficiently set up the data structures with discontinuous risk intervals for such models, which are more appropriate for many applications than the continuous alternatives. Finally, we apply these models to a real dataset to investigate the effect of gender on functional disability in a cohort of older persons. For comparison, we demonstrate modeling time to the first event.

RESULTS

The GEE Poisson, the Cox counting process, and the frailty models provided similar parameter estimates of gender effect on functional disability, that is, women had increased risk of bathing disability and other disability (disability in walking, dressing, or transferring) as compared to men. These results, especially for other disabilities, were quite different from those provided by an analysis of the first-event outcomes. However, the effect of gender was no longer significant in the counting process model fully adjusted for covariates.

CONCLUSION

Modeling time to only the first event may not be adequate. After properly setting up the data structures, repeated event models that account for the correlation between multiple events within subjects can be easily implemented with common statistical software packages.

Spatiotemporal patterns of postsynaptic density (PSD)-95 expression after rat spinal cord injury

AIMS

Postsynaptic density (PSD)-95 is a scaffolding protein linking the N-methyl-D-aspartate receptor with neuronal nitric oxide synthase (nNOS), which contributes to many physiological and pathological actions. We here investigated whether PSD-95 was involved in the secondary response following spinal cord injury (SCI).

METHODS

Spinal cord contusion (SCC) and spinal cord transection (SCT) models at thoracic (T) segment 9 (T(9)) were established in adults rats. Real-time polymerase chain reaction, Western blot, immunohistochemistry and immunofluorescence were used to detect the temporal profile and spatial distribution of PSD-95 after SCI. The association between PSD-95 and nNOS in the injured cords was also assessed by coimmmunoprecipation and double immunofluorescent staining.

RESULTS

The mRNA and protein for PSD-95 expression were significantly increased at 2 h or 8 h, and then gradually declined to the baseline level, ultimately up-regulated again from 5 days to 7 days for its mRNA level and at 7 days or 14 days for its protein level after either SCC or SCT. PSD-95 immunoreactivity was found in neurones, oligodendrocytes and synaptic puncta of spinal cord tissues within 5 mm from the lesion site. Importantly, injury-induced expression of PSD-95 was colabelled by active caspase-3 (apoptotic marker), Tau-1 (the marker for pathological oligodendrocytes) and nNOS.

CONCLUSIONS

Accompanied by the spatio-temporal changes for PSD-95 expression, the association between PSD-95 and nNOS undergoes substantial alteration after SCI. These two molecules are likely to form a complex on apoptotic neurones and pathological oligodendrocytes, which may in turn be involved in the secondary response after SCI.

Promoter hypermethylation of GPX3 as a predictor for chemoresistance and survival in head and neck cancer patients

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Background: Resistance of cancer cells to cisplatin and its analogues is the major limitation in clinical application of cisplatin-based chemotherapy. The mechanisms by which cancer cells develop resistance to the drugs are still unclear, and there is no way currently to predict the drug resistance of individual tumors. By genome-wide scanning of hypermethylated genes on head and neck cancer cells, we identified glutathione peroxidase 3 (GPX3) as one of the strong candidates whose promoter hypermethylation may be associated with head and neck chemoresistance. In this study, we investigated the potential predictive value of GPX3 methylation for head and neck cancer chemoresistance and patient prognosis. Methods: Promoter methylation and expression of GPX3 gene in head and neck cancer cell lines were examined by plasmid cloning, bisulfite DNA sequencing, reverse transcription-PCR and Western blot. GPX3 methylation in primary cancer tissues was assessed by real-time methylation-specific PCR (MSP). Forty-six head and neck cancer cases, for which chemotherapy response and survival were known, were selected for analysis. Correlation of GPX3 methylation and chemoresistance was tested using two-sided Fisher’s Exact Test and its prediction for patient survival was assessed using Kaplan-Meier survival analysis. Results: Loss of GPX3 expression was observed in 4 of 8 head and neck cancer cell lines and was consistent with cisplatin resistance. Demethylating treatment of the cell lines negative for GPX3 expression significantly restored its expression. Bisulfite DNA sequencing showed that the 5’ flanking promoter region of GPX3 was heavily hypermethylated in all cell lines with expression-silencing of the gene. In the 46 head and neck cancer cases analyzed by MSP, 15 of 23 non-responding cases (65%) showed GPX3 methylation, while 4 of 23 complete and partial response cases (17%) contained low levels of GPX3 methylation (Relative Risk 3.343, two sided Fisher’s exact test, P=0.002). Kaplan-Meier survival analysis showed a relative risk of death of 1.942 in patients with GPX3 methylation. Conclusions: Our findings suggest that GPX3 methylation is a strong candidate predictor for chemoresistance and prognosis of head and neck cancer patients.

No significant financial relationships to disclose.

Results of semimonthly 5-florouracil/leucovorin combined with paclitaxel and oxaliplatin in treatment of advanced gastric cancer (AGC)

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Background: At present there is still no standard chemotherapy regimen for AGC, the progress of AGC exhibits a pessimistic result with a median survival of less than 9 months. The purpose of this trial was designed to enhance the treatment efficacy for AGC by using semimonthly FU/LV combined with paclitaxel and oxaliplatin. Methods: Patients chosen with histologically proven diagnosis of adenocarcinoma of the stomach or gastroesophageal junction, locally advanced (i.e., unresectable) or metastatic and measurable disease. The chemotherapy regimen was comprised of a 3-hour infusion of 135 mg/m2 of paclitaxel followed by oxaliplatin 85 mg/m2 and LV 400 mg/m2, administered simultaneously as a 2-hour infusion, then continued a 46-hour infusion of FU 2.4 g/m2 using an ambulatory pump. Treatment was continued until disease progressed, unacceptable toxicity, or patient choice. The primary endpoint was response rate. Results: Twenty-seven patients were enrolled onto this study in our center between September 19, 2005 and December 25, 2006. The median patient age was 51 years (range, 28 to 66 years), 21 were males and 6 were females. All patients received the chemotherapy between at least two cycles and maximum eight cycles with a median of three. Four CRs of 27 enrolled patients, fifteen PRs and eight SDs were observed. Nineteen patients were chemonaive within enrolled patients: Four CRs, eleven PRs. At a median follow-up of 8.7 months, the median survival was 6.8 months. Frequent grade 3 to 4 toxicities were: neutropenia (37.0%), stomatitis (7.4%), nausea (7.4%), vomiting (7.4%), hepatic dysfunction (3.7%), paresthesia (18.5%). No treatment-related death occurred. Conclusion: Semimonthly FU/LV combined with paclitaxel and oxaliplatin appears to be of well efficacy and is well tolerated in patients with AGC. Currently, this regimen is being tested in the phase III trial involving patients with AGC on the basis of well result.

No significant financial relationships to disclose.

Amplification and specific expression of T-bet gene in nasal NK/T-cell lymphoma

To define the specific genetic alterations in nasal natural killer/T-cell lymphoma (N-NK/T-L), the assay of restriction landmark genomic scanning (RLGS), a genome-wide method, was used to investigate a pair of genomic DNA from N-NK/T-L cells and peripheral blood leukocytes of the same patient. The intensified spots in displayed N-NK/T-L gel of RLGS were subjected to bioinformatic analysis by virtual genome scan (VGS) and one of candidate spots proved to be T-bet gene (T-box expressed in T-cell). The pair of samples was consequently analysed by Southern hybridization, revealing genomic amplification of T-bet but not different status of DNA methylation. The amplification of T-bet was also discovered in other cases of N-NK/T-L by dot blotting. The expression of T-bet was investigated by in situ hybridization (ISH) and immunohistochemistry (IHC). The results showed that T-bet predominantly expressed in N-NK/T-L (ISH: 90.0%, 18/20; IHC: 80%, 16/20), while few cases of B-cell lymphoma (ISH: 11.8%, 2/17; IHC: 17.6%, 3/17) or T-cell lymphoma (ISH: 33.3%, 2/6; IHC: 16.7%, 1/6) were positive. The difference of T-bet expression in either ISH or IHC between N-NK/T-L and B-cell lymphoma or T-cell lymphoma was statistically significant (P < 0.05). Moreover, the expression of T-bet was not detected in normal spleen tissue and chronic inflammatory nasal mucosa. The results suggested that the amplification of T-bet gene or resulting its over-expression of T-bet gene might be involved in the development of N-NK/T-L and thus it should be worth confirming whether the over-expression of T-bet be helpful to the diagnosis of N-NK/T-L in further study.

Coronary artery occlusion alters expression of substance P and its mRNA in spinal dorsal horn in rats

The painful sensation during acute myocardial ischemia or infarction is a common symptom and results from neural activity in humans. Little is known about the role of neuropeptides in this effect of myocardial ischemia. The aim of the current study was to investigate the role of substance P in mediating the noxious neural signals in spinal cord in acute myocardial ischemia by exploring the change in substance P and its mRNA in thoracic dorsal root ganglia and spinal dorsal horn (T1-T5) after coronary artery occlusion. The experiment was performed with immunohistochemistry, enzyme immunoassay and real time reverse transcription-polymerase chain reaction techniques on rats' hearts. In acute myocardial ischemia (<6 h), substance P and preprotachykinin mRNA were up-regulated in the neurons of the dorsal root ganglia and spinal dorsal horn. The increase in the density of immunoreactive material was mainly observed in small-diameter neurons of the dorsal root ganglia and the superficial laminae (I and II) of the spinal cord. The increase in the expressions was statistically significant compared with the control and the sham surgery groups (P<0.05). The results suggest that substance P is involved in the mediation of the noxious neural signals of acute myocardial ischemia in spinal cord. The pathophysiological role and significance need to be investigated.

Differential responses of antioxidative system to chilling and drought in four rice cultivars differing in sensitivity

Responses of antioxidative defense systems to chilling and drought stresses were comparatively studied in four cultivars of rice (Oryza sativa L.) differing in sensitivity, two of them (Xiangnuo no. 1 and Zimanuo) are tolerant to chilling but sensitive to drought and the other two (Xiangzhongxian no. 2 and IR50) are tolerant to drought but sensitive to chilling. The seedlings of rice were transferred into growth chamber for 5 d at 8 degrees C as chilling treatment, or at 28 degrees C as control, or at 28 degrees C but cultured in 23% PEG-6000 solution as drought stress treatment. Under drought stress the elevated levels of electrolyte leakage, contents of H(2)O(2) and total thiobarbituric acid-reacting substances (TBARS) in Xiangzhongxian no. 2 and IR50 are lower than those in Xiangnuo no. 1 and Zimanuo. On the contrary, Xiangnuo no. 1 and Zimanuo have much lower level of electrolyte leakage, H(2)O(2) and TBARS than Xiangzhongxian no. 2 and IR50 under chilling stress. Activities of antioxidant enzymes (superoxide dismutase (SOD), catalase, and ascorbate-peroxidase (APX)) and contents of antioxidants (ascorbaic acid and reduced glutathione) were measured during the stress treatments. All of them were enhanced greatly until 3 d after drought stress in the two drought-tolerant cultivars, or after chilling stress in the two chilling-tolerant cultivars. They all were decreased at 5 d after stress treatments. On the other hand, activities of antioxidant enzymes and contents of antioxidants were decreased greatly in the drought-sensitive cultivars after drought stress, or in the chilling-sensitive cultivars after chilling stress. The results indicated that tolerance to drought or chilling in rice is well associated with the enhanced capacity of antioxidative system under drought or chilling condition, and that the sensitivity of rice to drought or chilling is linear correlated to the decreased capacity of antioxidative system.

Preconditioning and neurotrophins: a model for brain adaptation to seizures, ischemia and other stressful stimuli

The amino acid glutamate, the major excitatory neurotransmitter in the central nervous system, activates receptors coupled to calcium influx. Excessive activation of glutamate receptors in conditions such as severe epileptic seizures or stroke can kill neurons in a process called excitotoxicity. However, subtoxic levels of activation of the N-methyl-D-aspartate (NMDA) type of glutamate receptor elicit adaptive responses in neurons that enhance their ability to withstand more severe stress. A variety of stimuli induce adaptive responses to protect neurons. For example, sublethal ischemic episodes or a mild epileptic insult can protect neurons in a process referred to as tolerance. The molecular mechanisms that protect neurons by these different stressful stimuli are largely unknown but they share common features such as the transcription factor, nuclear factor kappa B (NF-kappaB), which is activated by ischemic and epileptic preconditioning as well as exposure to subtoxic NMDA concentrations. In this article, we describe stress-induced neuroprotective mechanisms highlighting the role of brain-derived neurotrophic factor (BDNF), a protein that plays a crucial role in neuronal survival and maintenance, neurogenesis and learning and memory.