Role of miR-133a in regulating TGF-β1 signaling pathway in myocardial fibrosis after acute myocardial infarction in rats

OBJECTIVE

The aim of this research was to explore the effect of microRNA-133a (miR-133a) on myocardial fibrosis and cardiac function after myocardial infarction in rats, and to investigate the possible regulatory mechanism.

MATERIALS AND METHODS

Myocardial infarction model was successfully established in rats by ligation of the left anterior descending coronary artery. After miR-133a overexpression in rats myocardium, cardiac function was examined by echocardiography. Meanwhile, the degree of myocardial fibrosis was detected by Masson staining. In addition, the expression of α-smooth muscle actin (α-SMA) in cardiomyocytes was detected by immunohistochemistry. Quantitative Real-time polymerase chain reaction (qRT-PCR) was performed to analyze the expression level of miR-133a in the junction of myocardial infarction. The mRNA expressions of transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), collagen type 1 (col 1), collagen type 3 (col 3) and α-SMA were measured by qRT-PCR as well. Furthermore, the protein levels of the above genes were detected by Western blotting.

RESULTS

MiR-133a expression in the infarct border zone of myocardial tissue was significantly decreased on the 28th day after myocardial infarction surgery (p<0.05). In addition, up-regulation of miRNA-133a in myocardial tissue of rats with myocardial infarction could remarkably improve cardiac function and reduce collagen volume fraction. Furthermore, the mRNA and protein expression levels of TGF-β1, CTGF, col1, col3, α-SMA in myocardial tissue were obviously decreased after miRNA-133a up-regulation (p<0.001).

CONCLUSIONS

Overexpression of miR-133a down-regulates the mRNA and protein levels of TGF-β1 and CTGF after myocardial infarction. Moreover, this may eventually reduce myocardial collagen deposition, inhibit myocardial fibrosis and improve cardiac function.

The correlation between intestinal mucosal lesions and hepatic dysfunction in patients without chronic liver disease

Patients with cirrhosis are known to develop small bowel mucosal lesions. However, the occurrence of mucosal lesions in patients with abnormal liver function test results in the absence of chronic liver disease has not been fully evaluated. This study aims to examine the association between small bowel endoscopic lesions and liver dysfunction in patients without confirmed chronic liver disease.Two hundred ninety six consecutive patients who met the selection criteria underwent capsule endoscopy. The severity of the small intestinal mucosal lesions was evaluated quantitatively using the Lewis scoring system, and hepatic dysfunction was evaluated using an algorithm-based combination scoring system with 8 individual serological markers.Small bowel lesions were observed in 121 patients (40.88%). Hepatic dysfunction was significantly more prevalent in patients with small bowel lesions than in those without lesions (33.1%; 40/121 and 5.7%; 10/175, respectively; P < .001). The mean serum ALT and AST levels were significantly higher in patients with small bowel lesions than in those without lesions (P = .007 and P = .004, respectively). The mean scores for AST to Platelet Ratio Index, Forns Index, S-Index, Fibrosis-4 Index and BARD were significantly higher in patients with small bowel lesions than those without lesions. The Lewis score significantly and positively correlated with the Forns Index (P = .008) and the FIB-4 Index (P = .006).There is a close correlation between small intestinal mucosal lesions and hepatic dysfunction. The severity of hepatic dysfunction is directly proportional to the severity of the small intestinal mucosal lesions in patients without confirmed chronic liver disease.

Effects of dietary calcium pyruvate on gastrointestinal tract development, intestinal health and growth performance of newly weaned piglets fed low-protein diets

AIM

This study was carried out to investigate the effects of dietary calcium pyruvate supplementation on growth performance and intestinal health of weaned piglets fed low-protein diets.

METHODS AND RESULTS

After a 7-day adaptation period, 60 individually housed piglets (Duroc × Yorkshire-Landrace) weaned at 28 days of age were randomly assigned to receive one of three treatments (20 pigs/treatment) for 28 days: control diet (20·0% crude protein [CP]), low-protein diet (15·5% CP), and experimental (15·5% CP + 1·8% calcium pyruvate). At the end of the experiment, six piglets from each diet group were slaughtered and blood and tissue samples were collected. Compared with the control group, feeding piglets with 15·5% CP decreased the daily body weight gain; lengths of the duodenum, jejunum and ileum; and weights of the stomach, duodenum, jejunum and ileum (P < 0·05), while 15·5% CP + 1·8% calcium pyruvate supplementation removed those differences (P > 0·05). Compared with the control group, the diarrhoea incidence and relative richness of Firmicutes in the colon contents of piglets in both the 15·5% CP and 15·5% CP + 1·8% calcium pyruvate groups was decreased. The relative richness of Bacteriodetes in the colon contents of piglets was higher in the 15·5% CP + 1·8% calcium pyruvate group than in the control and 15·5% CP groups (P < 0·05).

CONCLUSION

Calcium pyruvate supplementation for four weeks removed the negative effects of a low-protein diet on the gastrointestinal tract development and daily body weight gain of weaned piglets.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study showed that supplementing a low-protein diet with calcium pyruvate, an effective alternative metabolic fuel to amino acids, was beneficial in improving the intestinal health and maximizing the growth of newly weaned piglets.

[Detection and prevention of nitrous oxide iatrogenic pollution in dental treatments]

Nitrous oxide (N(2)O), also known as laughing gas, is widely used in the dental offices as a common inhaled sedative analgesic gas to reduce anxiety and pain during treatment. Studies have shown that long-term exposure to higher concentrations of laughing gas may have a certain impact on the health of medical staff, while currently research on iatrogenic pollution in applications of laughing gas in oral therapy is not sufficient. In the United States and Europe, the condition of applications of laughing gas is relativrly mature, and there are related regulations and recommended measures to prevent and control iatrogenic pollution. However, studies in these countries still show that there is iatrogenic pollution in the clinical use of laughing gas and lack of uniform detection measures. While, in China, there is little research on the health effects of laughing gas on medical staff and on how to detect and control nitrous oxide pollution. This review is about the hazards, monitoring and control of clinical application of nitrous oxide.

Synergistic effect of bone marrow-derived mesenchymal stem cells and platelet-rich plasma in streptozotocin-induced diabetic rats

Background

Diabetic wounds are a major clinical challenge, because minor skin wounds can lead to chronic, unhealed ulcers and ultimately result in infection, gangrene, or even amputation. Studies on bone marrow derived mesenchymal stem cells (BMSCs) and a series of growth factors have revealed their many benefits for wound healing and regeneration. Platelet-rich plasma (PRP) may improve the environment for BMSC development and differentiation. However, whether combined use of BMSCs and PRP may be more effective for accelerating diabetic ulcer healing remains unclear.

Objective

We investigated the efficacy of BMSCs and PRP for the repair of refractory wound healing in a diabetic rat model.

Methods

Forty-eight rats with diabetes mellitus induced by streptozotocin were divided into four groups: treatment with BMSCs plus PRP, BMSCs alone, PRP alone, phosphate buffered saline. The rate of wound closure was quantified. A histopathological study was conducted regarding wound depth and the skin edge at 7, 14, and 28 days after surgery.

Results

Wound healing rates were significantly higher in the BMSC plus PRP group than in the other groups. The immunohistochemistry results showed that the expression of platelet/endothelial cell adhesion molecule 1, proliferating cell nuclear antigen, and transforming growth factor-β1 increased significantly in the BMSC plus PRP group compared to the other treatment groups. On day 7, CD68 expression increased significantly in the wounds of the BMSC plus PRP group, but decreased markedly at day 14 compared to the controls.

Conclusion

The combination of BMSCs and PRP aids diabetic wound repair and regeneration.

A tuberculosis outbreak among senior high school students in China in 2011

OBJECTIVE

An outbreak of pulmonary tuberculosis (PTB) occurred in students attending Licai Training School, Gujiao City, China, in early 2011. The epidemic characteristics and possible contributory factors relating to the spread of this outbreak of PTB were studied in a field investigation and are reported here.

METHODS

Cases were detected by PTB symptom screening, tuberculin skin testing (TST), chest X-radiography, and examination of sputum smears and cultures for all students, school staff and close family contacts of patients with PTB.

RESULTS

Of the 287 students attending the school, 45 (15.7%) were diagnosed with PTB and two (0.7%) had a positive smear. No PTB was found among staff and close family contacts. Prevalence was high in Science Class 27 and the two floors of the dormitory building where the smear-positive TB patients studied and lived. The frequency of strong TST positivity was also high in Science Class 27 and among close contacts living in the same dormitories as the PTB patients.

CONCLUSIONS

Several avoidable factors likely to have enhanced disease transmission were identified and several recommendations are made to reduce the risk of future TB outbreaks in schools.

Silencing of human ferrochelatase causes abundant protoporphyrin-IX accumulation in colon cancer

Hemes and heme proteins are vital components of essentially every cell of virtually every eukaryote organism. Previously, we demonstrated accumulation of the heme precursor protoporphyrin-IX (PpIX) in gastrointestinal tumor tissues. To elucidate the mechanisms of PpIX accumulation by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), we studied expression of the relevant enzymes of the heme synthetic pathway. Here, we describe a significant down-regulation of ferrochelatase (FECH) mRNA expression in gastric, colonic, and rectal carcinomas. Accordingly, in an in vitro model of several carcinoma cell lines, ferrochelatase down-regulation and loss of enzymatic activity corresponded with an enhanced PpIX-dependent fluorescence. Direct detection of PpIX in minute amounts was achieved by a specifically developed pulsed solid-state laser dual delay fluorimetry setup. Silencing of FECH using small interfering RNA (siRNA) technology led to a maximum 50-fold increased PpIX accumulation, imageable by a specifically adapted two-photon microscopy unit. Our results show that in malignant tissue a transcriptional down-regulation of FECH occurs, which causes endogenous PpIX accumulation. Furthermore, accumulation of intracellular PpIX because of FECH siRNA silencing provides a small-molecule-based approach to molecular imaging and molecular therapy.

Restricted feeding entrains liver clock without participation of the suprachiasmatic nucleus

BACKGROUND

There are two main stimuli that entrain the circadian rhythm, the light-dark cycle (LD) and restricted feeding (RF). Light-induced entrainment requires induction of the Per1 and Per2 genes in the suprachiasmatic nucleus (SCN), the locus of a main oscillator. In this experiment, we determined whether RF resets the expression of circadian clock genes in the mouse liver with or without participation of the SCN.

RESULTS

Mice were allowed access to food for 4 h during the daytime (7 h advance of feeding time) under LD or constant darkness (DD). The peaks of mPer1, mPer2, D-site-binding protein (Dbp) and cholesterol 7alpha-hydroxylase (Cyp7A) mRNA in the liver were advanced 6-12 h after 6 days of RF, whereas those in SCN were unaffected. The advance of mPer expression in the liver by RF was still observed in SCN-lesioned mice. A 7 h advance in the LD cycle advanced the peaks of clock gene expression in both the liver and SCN, whereas, a shift in the LD did not move the phase of the liver clock when the shift was carried out under a fixed RF schedule during the night-time.

CONCLUSIONS

These results suggest that restricted feeding strongly entrained the expression of circadian clock genes in the liver without the participation of an SCN clock function.

[The first discovery of endemic Lyme disease in Shandong province]

OBJECTIVE

To investigate the endemic area of Lyme disease in Shandong province.

METHODS

An investigation on endemic Lyme disease was conducted by means of serological and etiological methods in Shandong province from 1992 to 1999.

RESULTS

Of 1919 forestry residents, 120 residents had a significant antibody titer against Borolo burgdorferi strain B(31). The prevalance rate of Lyme disease was 6.25%. Haemaphysalis longicornis was a prevailing species of Ixodidae in the region. Spirochetes were observed in the midguts of 50 H. longicornis in this area by direct fluorescence antibody method. The overall positive rate was 12.0% (6/50). Two strains (TSH(1), TSH(3)) of spirochetes were isolated from H. longicornis. Both TSH(1) and TSH(3) were positively responded to McAb H(5332) and H(9724), but negatively to H(6831). Spirochetes were observed in the kidneys of 46 Rattus in this area by direct fluorescence antibody method with a positive rate of 13.26% (6/46).

CONCLUSION

It was the first time that the mountainous areas in Shandong province was confirmed endemic areas of Lyme disease.

[Effects of lentinan of peripheral blood mononuclear cell expression of interleukin-2 receptor in patients with chronic hepatitis B in vivo and in vitro]

The effects of lentinan on peripheral blood mononuclear cell (PBMC) expression of IL-2 receptor in patients with chronic hepatitis B in vitro and in vivo were studied. The expression percentage of IL-2 receptor in 44 patients with chronic hepatitis before treatment was 36.74 +/- 7.74, which was lower than healthy subjects, and was 48.92 +/- 3.79 after 2 months treatment of lentinan, which was approximated the normal control. PBMC from 30 patients with chronic hepatitis B were cultured in vitro with or without lentinan. The percentage of expression IL-2 receptor was 12.81 +/- 2.62 without lentinan and was 35.70 +/- 4.87 in the presence of lentinan. The concentration of lentinan stimulating expression of IL-2 receptor was between 0.2 to 200 g.ml-1. The results suggest that lentinan stimulates expression of IL-2 receptor on PBMC, which is associated with the therapeutic effectiveness of lentinan treatment.

Involvement of ryanodine receptor type 3 in dopamine release from the striatum: evidence from mutant mice lacking this receptor

Although it is known that ryanodine receptor type 3 is expressed in the striatum, the function of this receptor has not been elucidated. Therefore, we examined whether caffeine- and ryanodine-induced dopamine release in striatal slices is affected in mice lacking ryanodine receptor type 3. Pretreatment with thapsigargin, an inhibitor of the Ca(2+) ATPase pump of the endoplasmic reticulum, abolished caffeine- or ryanodine-induced dopamine release in slices from normal mice. Dopamine concentration in the striatum and KCl-induced dopamine release were unaffected by a ryanodine receptor type 3 deficiency. Ryanodine-induced dopamine release was significantly attenuated in mice lacking ryanodine receptor type 3, whereas caffeine-induced dopamine release was partially attenuated. Caffeine produced a similar hyper-motor activity in both wild and homozygous mice. The present results suggest the involvement of ryanodine receptor type 3 in dopamine release from the striatum.

An exploration of the sequence of a 2.9-Mb region of the genome of Drosophila melanogaster: the Adh region

A contiguous sequence of nearly 3 Mb from the genome of Drosophila melanogaster has been sequenced from a series of overlapping P1 and BAC clones. This region covers 69 chromosome polytene bands on chromosome arm 2L, including the genetically well-characterized "Adh region." A computational analysis of the sequence predicts 218 protein-coding genes, 11 tRNAs, and 17 transposable element sequences. At least 38 of the protein-coding genes are arranged in clusters of from 2 to 6 closely related genes, suggesting extensive tandem duplication. The gene density is one protein-coding gene every 13 kb; the transposable element density is one element every 171 kb. Of 73 genes in this region identified by genetic analysis, 49 have been located on the sequence; P-element insertions have been mapped to 43 genes. Ninety-five (44%) of the known and predicted genes match a Drosophila EST, and 144 (66%) have clear similarities to proteins in other organisms. Genes known to have mutant phenotypes are more likely to be represented in cDNA libraries, and far more likely to have products similar to proteins of other organisms, than are genes with no known mutant phenotype. Over 650 chromosome aberration breakpoints map to this chromosome region, and their nonrandom distribution on the genetic map reflects variation in gene spacing on the DNA. This is the first large-scale analysis of the genome of D. melanogaster at the sequence level. In addition to the direct results obtained, this analysis has allowed us to develop and test methods that will be needed to interpret the complete sequence of the genome of this species. Before beginning a Hunt, it is wise to ask someone what you are looking for before you begin looking for it. Milne 1926

[Preliminary investigation on reservoir hosts of Borrelia burgdorferi in China]

From 1987 to 1997, the reservoir hosts of Borrelia burdorferi(B.b.) were investigated in 16 provinces, municipalities and autonomous regions of China. Seroepidemiological findings indicated that cattle, sheep, dogs and rats from forest areas had a high antibody titer for B.b. (B31) with positive rates of 18.18%-32.61%, 17.12%-61.21%, 38.50-60.00% and 41.18%-86.05% respectively. Using BSK medium, 20 strains of B.b. were isolated from Apodemus agrarius, Clethrionomys rufocanus, Eutamias sibiricus, Rattus coxingi, Rattus norvegicus, Rattus edwardsi, Rattus confucianus, Rattus fulvescens and Caprolagus sinensis. These spirochetal strains were identified as B.b. by indirect immunofluorescence assay using species and genus specific monoclonal antibodies. Vertical transmission of B.b. was confirmed with B.b. isolated from foetuses of Apodemus agrarius and Rattus edwardsi. The results showed that lyme disease spirochetes, B.b., might be naturally maintained in an enzootic cycle by transplacental transmission. Apodemus agrarius and Clethrionomys rufocanus might serve as major reservoir hosts for B.b. in China.

[Investigation on primary vectors of Borrelia burgdorferi in China]

From 1987 to 1997, primary vectors of borrelia burgdorferi sensu lato (B.b.s.l.) were investigated in China. A total number of 17,000 ticks collected from 20 provinces, city and autonomous region were classified, including 2 families 8 genus 23 species. There were 108 isolates of B.b.s.l. discovered from 8 species of ticks, including Ixodes persulcatus, I. granulatus, I. acutitarsus, Haemaphysalis concinna, H. longicornis, H. bispinosis, H. cornigera taiwana and Dermacentor silvarum. Ixodes persulcatus was found as the dominant species, accounted for more than 80% of the total number of collected ticks. 20 to 45 per cent adult Ixodes persulcatus contained spirochetes as determined by direct immunofluorescence in the northeast and northwest areas. Seasonal change of adult Ixodes persulcatus was coincident with patients with erythema chronicum migrans. These studies proved that Ixodes persulcatus played a leading role in the transmission of B.b.s.l. to human being in northern region of China. Haemaphysalis bispinosis and Ixodes granulatus were identified as the dominant species with 16 to 40 per cent adult Haemaphysalis bispinosis and 24% per cent adult Ixodes granulatus containing spirochetes as determined by direct immunofluorescence in the southern region of China. Haemaphysalis bispinosis and Ixodes granulatus were proved to be important vectors of B.b.s.l. in the southern area of China.

[Study on the elimination of bacteria from the cultures of Lyme disease spirochetes (Borrelia burgdorferi)]

Contaminated cultures of strains H11, H20 from ticks, and strain R9 from patient were purified by antisera for bacteria, chemicals, filtration dilution and animal inoculation. Most of bacteria were eliminated after adding antisera into contaminated strains H11, H20. The preliminarily decontaminated cultures of strains H11, H20 or those with a few bacteria such as strain R9 could be completely purified by filtration, chemicals, dilution, or animal inoculation, but filtration is the simplest and the most effective purification method.

Structural heterogeneity of the alpha subunits of the nicotinic acetylcholine receptor in relation to agonist affinity alkylation and antagonist binding

The structural basis for the heterogeneity of the two agonist binding sites of the Torpedo californica acetylcholine receptor with respect to antagonist binding and reactivity toward affinity alkylating reagents was investigated. There is one agonist binding site on each of the two alpha subunits in a receptor monomer. One of these sites is easily affinity labeled with bromoacetylcholine, while more extreme conditions are required to label the other. Evidence is presented that the site which is easily labeled with bromoacetylcholine is the site with higher affinity for the antagonist d-tubocurarine. Digestion of purified alpha subunits with staphylococcal V8 protease gave two limit fragments with apparent molecular weights of 17K and 19K. Both of these fragments began at residue 46 of the alpha sequence, and both reacted with monoclonal antibodies specific for the sequence alpha 152-159 but not with antibodies specific for alpha 235-242. Their tryptic peptide maps and reactivity with a number of monoclonal antibodies were virtually identical. Only the 17-kilodalton (17-kDa) fragments stained heavily for sugars with Schiff's reagent. However, both fragments bound 125I-labeled concanavalin A. Complete removal of carbohydrate detectable with concanavalin A from V8 protease digests of alpha subunits resulted in two fragments of lower apparent molecular weights, indicating that these fragments differed not only in carbohydrate content but also in their C-termini or by another covalent modification. Covalent labeling of one of the two agonist sites of the intact receptor with bromo[3H]acetylcholine followed by digestion with V8 protease resulted in labeling of only the 19-kDa fragment.(ABSTRACT TRUNCATED AT 250 WORDS)

Single-channel recordings from purified acetylcholine receptors reconstituted in bilayers formed at the tip of patch pipets

The channel of the purified acetylcholine receptor from Torpedo californica electric organ reconstituted in lipid vesicles was assayed by direct electrical recording using patch-clamp pipets. High-resistance seals were obtained by gentle suction of vesicles into the pipet or after the formation of lipid bilayers from monolayers at the tip of the pipet. Single-channel currents were activated by three cholinergic ligands: acetylcholine, carbamylcholine, and suberyldicholine. The single-channel conductance, gamma, was 40 +/- 5 pS in 0.5 M NaCl, irrespective of the agonist used. The distributions of channel open times were fitted by a sum of two exponentials. The lifetimes of the two exponential components were a factor of 2 longer for suberyldicholine than for acetylcholine or carbamylcholine. At desensitizing concentrations of agonists the single events appeared in paroxysms of channel activity followed by quiescent periods. These results suggest that the full cycle of solubilization, purification, and reconstitution of this membrane receptor can be achieved without impairment of channel function.

Interaction of Sindbis virus glycoproteins during morphogenesis

In cells infected with the Sindbis temperature-sensitive mutants ts-23 and ts-10 (complementation group D), which contain a defect in the envelope glycoprotein E1, the precursor polypeptide PE2 is not cleaved to the envelope glycoprotein E2 at the nonpermissive temperature. This defect is phenotypically identical to the defect observed in the complementation group E mutant, ts-20. The lesion in ts-23 is reversible upon shift to permissive temperature, whereas that of ts-10 is not. Antiserum against whole virus, E1, or E2 also prevents the cleavage of PE2 in cells infected with wild-type Sindbis virus. Because the cleavage of PE2 is inhibited by the lesion in mutants that are genotypically distinct and by anti-E1 or -E2 serum, it appears that PE2 and E1 exist as a complex in the membrane of the infected cell.

Homologous interference induced by Sindbis virus

Homologous interference during Sindbis virus infection has been investigated. Prior infection of either chicken embryo fibroblast or BHK(21) cell cultures results in reduced yields of progeny virions of the superinfecting genotype. This reduction in yield results from a reduction in the number of cells in the cultures capable of producing the superinfecting genotype. The development of interference parallels the attachment kinetics of Sindbis virus. Interference requires an active viral genome since the activity is sensitive to inactivation by ultraviolet light, and an RNA(-) mutant, ts-24, fails to induce interference under nonpermissive conditions. However, ts-6, an RNA(-) mutant belonging to a different complementation group, and the RNA(+) mutants, ts-2 and ts-20, interfere at both permissive and nonpermissive temperatures.