Neuroprotective effect of deep hypothermic circulatory arrest with low priming volume: study in a rabbit model

OBJECTIVE

The aim of the study was to investigate the possible neuroprotective effects of a low priming volume following deep hypothermic circulatory arrest (DHCA) in a rabbit model.

METHODS

Rabbits were randomized into three groups: DHCA with low priming volume (Group L), DHCA with high priming volume (Group H), and sham-operated group (Group S). The priming volume of Groups L and H were 75 ml and 210 ml, respectively. The rabbits were simultaneously placed on CPB and brain microdialysis, cooled to 16 to 18 degrees C with DHCA for 60 minutes. Physiological parameters were regularly recorded. The extracellular levels of glutamate, glucose, lactate, and pyruvate in the hippocampus were collected by microdialysis and measured by HPLC and a microdialysis analyzer. Brain damage was evaluated with light microscopy and electron microscopy and TUNEL staining.

RESULTS

In order to keep the mean arterial pressure and acid-base balance within defined physiological ranges, more doses of dopamine and sodium bicarbonate were administered in Group H than in Group L (P < 0.05). The ratios of lactate/glucose and lactate/pyruvate in Group H increased significantly compared with those in Group L from the beginning of weaning from CPB (P < 0.05). The levels of extracellular glutamate in the two DHCA groups increased significantly (P < 0.05). After weaning from CPB, the glutamate values in Group H remained at higher levels compared with those in Group L (P < 0.05). The percentage of injured neurons, TUNEL positive staining, and the mitochondria score of the hippocampus CA1 in Group H were significantly higher than in Group L (P < 0.05).

CONCLUSIONS

A low priming volume during DHCA could have a neuroprotective effect compared with a high priming volume.

Metabotropic glutamate receptors subtype 5 are necessary for the enhancement of auditory evoked potentials in the lateral nucleus of the amygdala by tetanic stimulation of the auditory thalamus

The lateral nucleus of the amygdala (LA) receives axonal projections from the auditory thalamus, the medial geniculate nucleus (MGN), and mediates auditory fear conditioning. Tetanic electrical stimulation of the MGN can induce long-term potentiation of acoustically-evoked responses (AEPs) recorded in the LA of anesthetized rats. The present study investigated the temporal development of tetanus-induced AEP potentiation recorded in the LA of anesthetized rats during the recording time up to 120 min after tetanization. In addition, the present study investigated whether the artificially-induced AEP potentiation is mediated by the metabotropic glutamate receptors subtype 5 (mGluR5). The results show that AEPs recorded in the LA to a broadband-noise burst were significantly enhanced immediately after tetanic but not low-frequency stimulation of the MGN. The AEP potentiation was well retained up to 120 min after tetanization. High-dose (1.5 microg/4 microl) microinjection of the selective antagonist of mGluR5, 2-methyl-6-(phenylethynyl)-pyridine (MPEP), into the ipsilateral lateral ventricle 30 min before tetanization completely blocked the AEP potentiation without affecting the baseline AEP. Low-dose (0.5 microg/4 microl) microinjection partially suppressed the AEP potentiation. When the high-dose MPEP was injected 40 min after tetanization, the AEP potentiation was not affected. These results indicate that in anesthetized rats mGluR5 receptors are necessary for the induction or early maintenance (40 min) of AEP potentiation in the LA by tetanic stimulation of the MGN.

Chinese medicinal herbs for acute bronchitis

BACKGROUND

Acute bronchitis is one of the most common diagnoses made by primary-care physicians. It is traditionally treated with antibiotics (although the evidence for their effectiveness is weak and modest at best), and other even less effective treatments. Chinese medicinal herbs have also been used as a treatment.

OBJECTIVES

This review aimed to summarise the existing evidence on the comparative effectiveness and safety of Chinese medicinal herbs for treating uncomplicated acute bronchitis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2007, Issue 1), which includes the Cochrane Acute Respiratory Infections Group's specialised register; MEDLINE (1966 to March Week 1, 2007); EMBASE (1988 to January 2007); The Chinese Cochrane Centre's Controlled Trials Register (up to January 2007); and the Chinese Biomedical Database (CBM) (1980 to January 2007).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing Chinese medicinal herbs with placebo, antibiotics or other Western medicines for the treatment of uncomplicated acute bronchitis.

DATA COLLECTION AND ANALYSIS

At least two review authors independently extracted data and assessed trial quality.

MAIN RESULTS

No studies met the inclusion criteria for this review. One study with 300 participants but uncertain randomisation was analysed . The study showed that treatment with the Chinese medicinal herb Huoke granules leads to a shorter duration of cough, fever and sputum compared to using penicillin and Xiaoer Shangfeng Zhike tangjiang syrup. However, the study also lacked allocation concealment and blinding. There was a high possibility of conflict of interest as the Huoke granules were made by the trial author's hospital.

AUTHORS' CONCLUSIONS

There is insufficient quality data to recommend the routine use of Chinese herbs for acute bronchitis. Study-design limitations of the individual studies meant that no conclusion about the benefits of Chinese herbs could be taken. In addition, the safety of Chinese herbs is unknown due to the lack of toxicological evidence on these Chinese herbs, though adverse events were reported in some case reports.

Relativistic laser channeling in plasmas for fast ignition

We report an experimental observation suggesting plasma channel formation by focusing a relativistic laser pulse into a long-scale-length preformed plasma. The channel direction coincides with the laser axis. Laser light transmittance measurement indicates laser channeling into the high-density plasma with relativistic self-focusing. A three-dimensional particle-in-cell simulation reproduces the plasma channel and reveals that the collimated hot-electron beam is generated along the laser axis in the laser channeling. These findings hold the promising possibility of fast heating a dense fuel plasma with a relativistic laser pulse.

Association of the +33371 A/G polymorphism in adiponectin receptor 2 gene with Type 2 diabetes in the Chinese population

PURPOSE

The aim of this study was to investigate the association between the +33371 A/G polymorphism of adiponectin receptor 2 gene and the risk of Type 2 diabetes (T2DM) in the Chinese population.

METHODS

A case-control study was performed among 594 unrelated Chinese people. All of them underwent a standardized assessment on phenotypic characterization including anthropometry, 75-g oral glucose tolerance test with insulin levels, fasting serum total cholesterol, and fasting serum triglyceride. The +33371 A/G polymorphism was detected by PCR-restriction fragment length polymorphism.

RESULTS

The PCR products after digestion displayed 3 genotypes, including AA, AG, and GG. The frequencies of AA, AG, and GG genotypes in T2DM group (no.=261) and control group (no.=353) were 0.379, 0.414, 0.207 and 0.162, 0.541, 0.297, respectively. There was a significant difference in both genotypic and allelic frequencies distribution of +33371 A/G polymorphism between T2DM and control subjects (p<0.001). Subjects with AA+AG genotypes showed higher levels of fasting plasma glucose (p=0.024), fasting serum triglycerides (p=0.036), and body mass index (BMI) (p=0.013) than those with GG genotype in the T2DM group but not in the control group. Compared with GG genotype, AA (p<0.001) and AA+AG (p=0.002) genotype group had a significantly higher risk of T2DM, with odds ratio (OR) for 2.290 [95% confidence interval: 1.482-3.359] and 1.963 (1.183-2.997). Compared with AG+GG genotype group, the risk of T2DM in AA genotype increased slightly (p=0.007), with OR for 1.478 (1.025-2.036).

CONCLUSION

The present findings suggest that +33371 A/G polymorphism is associated with increased risk of T2DM and multiple insulin resistance-related phenotypes (including fasting plasma glucose, fasting serum triglycerides, and BMI) in the Chinese population.

Chinese medicinal herbs for influenza

BACKGROUND

Influenza is an acute respiratory communicable disease which, during epidemics, can cause high morbidity and mortality. Traditional Chinese medicinal herbs, often administered following a particular theory, may be a potential medicine of choice.

OBJECTIVES

To assess the effect of Chinese medicinal herbs in preventing and treating influenza, and to estimate the frequency of adverse effects.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2007), which includes the Cochrane Acute Respiratory Infections Review Group specialised register; MEDLINE (January 1966 to January 2007); EMBASE (January 1988 to January 2007); CBM (Chinese Biomedical Database) (January 1980 to January 2007); and the Chinese Cochrane Center's Controlled Trials Register (up to January 2007). We also searched Current Controlled Trials (www.controlled-trials.com) and the National Research Register (http://www.update-software.com/National/) for ongoing trials and reference lists of articles. For more information we telephoned and wrote to researchers in the field, as well as trial authors of studies evaluated in the review

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing traditional Chinese medicinal herbs with placebo, no treatment, or chemical drugs normally used in preventing and treating uncomplicated influenza patients.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality.

MAIN RESULTS

Two studies involving 1012 participants were reviewed. The methodological quality of both studies was 'poor'. Included RCTs separately compared two medicinal herbs with two different antiviral drugs, precluding any pooling of results. 'Ganmao' capsules were found to be more effective than amantadine in decreasing influenza symptoms and speeding recovery in one study, (in which adverse reactions were mentioned in the amantadine group although no data were reported). There were no significant differences between 'E Shu You' and ribavirin in treating influenza, nor in the occurrence of adverse reaction.

AUTHORS' CONCLUSIONS

The present evidence is too weak to support or reject the use of Chinese medicinal herbs for preventing and treating influenza. More RCTs with good methodological quality, larger numbers of participants and clear reporting are needed in the future. We recommend that all the clinical trials registered in the Chinese Clinical Trial Register and Chinese journals join in the Joint Statement of Establishing Chinese Clinical Trial Registration and Publishing System.

Aortic growth rates in chronic aortic dissection

AIM

To determine and compare rates of descending aortic enlargement and complications in chronic aortic dissection with and without a proximal aortic graft.

METHODS AND MATERIALS

Fifty-two patients with dissection involving the descending aorta and who had undergone at least two computed tomography (CT) examinations at our institution between November, 1993 and February, 2004 were identified, including 24 non-operated patients (four type A, 20 type B) and 28 operated patients (type A). CT examinations per patient ranged from two to 10, and follow-up ranged from 1-123 months (mean 49 months, median 38.5 months). On each CT image, the aortic short axis (SA), false lumen (FL), and true lumen (TL) diameters were measured at the longitudinal midpoint of the dissection and at the point of maximum aortic diameter. Complications were tabulated, including aortic rupture and aortic enlargement requiring surgery.

RESULTS

For non-operated patients, the midpoint and maximum point SA, TL, and FL diameters increased significantly over time. For operated patients, the midpoint and maximum point SA and FL diameters increased significantly over time. In both groups, aortic enlargement was predominantly due to FL expansion. Diameter increases in non-operated patients were significantly larger than those in operated patients. The rate of change in aortic diameter was constant, regardless of aortic size. Four non-operated and six operated patients developed aortic complications.

CONCLUSIONS

In patients with a dissection involving the descending thoracic aorta, the FL increased in diameter over time, at a constant rate, and to a greater degree in non-operated patients (mostly type B) compared with operated patients (all type A).

Evaluation of an independent prestin mouse model derived from the 129S1 strain

Studies using the prestin knockout mouse indicate that removal of the outer hair cell (OHC) motor protein is associated with loss of sensitivity, frequency selectivity and somatic electromotility. Here we provide data obtained from another prestin mouse model that was produced commercially. In vivo electrical recordings from the round window indicate that the phenotype is similar to that of the original knockout generated by the Zuo group at St. Jude Children's Research Hospital. Hence, compound action potential (CAP) thresholds are shifted in a frequency-dependent manner and CAP tuning curves at 12 kHz are flat for masker frequencies between 3 and 18 kHz. Although CAP input-output functions at 6 kHz show a shift in sensitivity at low levels, responses approach wild-type magnitudes at high levels where the cochlear amplifier has less influence. In order to confirm that the loss of sensitivity and frequency selectivity is due to loss of prestin, we performed immunohistochemistry using a prestin antibody. Cochlear segments from homozygous mutant mice showed no fluorescence, while wild-type mice displayed a fluorescent signal targeted to the OHC's lateral membrane. Absence of prestin protein was confirmed using LDS-PAGE/Western blot analysis. These results indicate that the loss of function phenotype is associated with loss of prestin protein. Lack of prestin protein also results in a shortening of OHC length to approximately 60% of wild-type, similar to that reported previously by Liberman's group. The linkage shown between the loss of prestin protein and abnormal cochlear function validates the original knockout and attests to the importance of OHC motor function in the auditory periphery.

Effects of Ionic Liquid as Additive and the pH of the Mobile Phase on the Retention Factors of Amino Benzoic Acids in RP-HPLC

As an organic salt, ionic liquids are widely used as new solvent media. In this paper, three positional isomers, such as o-amino benzoic acid, m-amino benzoic acid, and p-amino benzoic acid are separated with four different ionic liquids as additives to the mobile phase using reversed-phase (RP) high-performance liquid chromatography (HPLC). Amino benzoic acids are biologically active substances; the p-isomer is present in a group of water-soluble vitamins and is widely known as a sunscreen agent. The ionic liquids used are 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium methylsulfate, and 1-octyl-3-methylimidazolium methylsulfate. The effects of the length of the alkyl group on the imidazolium ring and its counterion, the concentrations of the ionic liquid, and the effect of the pH of the mobile phase on the retention factor of the amino benzoic acid isomers are studied. Separation with the ionic liquid in the eluent was better than the separation without the ionic liquid. The pH mainly affected the retention and elution order of the solutes in RP-HPLC.

Development of temporal response properties and contrast sensitivity of V1 and V2 neurons in macaque monkeys

The temporal contrast sensitivity of human infants is reduced compared to that of adults. It is not known which neural structures of our visual brain sets limits on the early maturation of temporal vision. In this study we investigated how individual neurons in the primary visual cortex (V1) and visual area 2 (V2) of infant monkeys respond to temporal modulation of spatially optimized grating stimuli and a range of stimulus contrasts. As early as 2 wk of age, V1 and V2 neurons exhibited band-pass temporal frequency tuning. However, the optimal temporal frequency and temporal resolution of V1 neurons were much lower in 2- and 4-wk-old infants than in 8-wk-old infants or adults. V2 neurons of 8-wk-old monkeys had significantly lower optimal temporal frequencies and resolutions than those of adults. Onset latency was longer in V1 at 2 and 4 wk of age and was slower in V2 even at 8 wk of age than in adults. Contrast threshold of V1 and V2 neurons was substantially higher in 2- and 4-wk-old infants but became adultlike by 8 wk of age. For the first 4 wk of life, responses to high-contrast stimuli saturated more readily in V2. The present results suggest that although the early development of temporal vision and contrast sensitivity may largely depend on the functional maturation of precortical structures, it is also likely to be limited by immaturities that are unique to V1 and V2.