Association analysis between carcass weight and meat quality of Bamei pigs.

A total of 48 crossbred Bamei pig carcasses were divided into three groups (A, 60-69 kg; B, 70-79 kg; and C, 80-90 kg) to investigate the influence of carcass weight on meat quality. The intramuscular fat content of the three groups increased from 2.20% (Group A) to 4.14% (Group C). Group B had higher drip loss (6.83%, P < 0.05) than the other two groups. Warner-Bratzler shear force decreased with increasing weight (61.16 > 51.63 > 43.64 N, P < 0.05). No significant differences were observed in meat color, cooking percentage, and water holding capacity among the three groups. The polyunsaturated fatty acids/saturated fatty acids ratio in group B (0.23) was significantly higher than that in the other two groups. In conclusion, our results suggested that a carcass weight of 70-79 kg is suitable for the production of Bamei pigs.

Comparison between meat quality of Hanzhong White pigs and carcass weight.

A total of 48 carcasses of crossbred Hanzhong White pigs were divided into 3 groups (I, 90-99 kg; II, 100-109 kg; III, 110-119 kg) to investigate the influence of carcass weight on meat quality. The intramuscular fat content of the 3 groups increased from 1.90 to 4.90%; for meat color, Warner-Bratzler shear force, drip loss, and oxidation-type muscle fiber percentage, and muscle fiber diameter of the longissimus lumborum, the indices in group II and group III were better than those in group I (P < 0.05). The saturated fatty acid and polyunsaturated fatty acid percentages of the longissimus lumborum muscle (2.80 and 37.30%, respectively) in group II were significantly lower than those in the other 2 groups, while the monounsaturated fatty acid percentage was the highest (59.10%). In conclusion, our results suggest that a carcass weight of 100-109 kg is sufficient to produce acceptable meat quality of Hanzhong White pigs.

Obese and lean porcine difference of FoxO1 and its regulation through C/EBPß and PI3K/GSK3ß signaling pathway.

Forkhead box O 1 (FoxO1) is an important transcription factor implicated in adipogenesis. In this study, we detected the breed differences in FoxO1 between Bamei pigs (an obese breed) and Large White pigs (a lean breed). Compared with Large White pigs, the BW of Bamei pigs was lower (P < 0.01), but back fat thickness, fat percent, and intramuscular fat content were greater (P < 0.01). The levels of FoxO1 mRNA and protein were lower (P < 0.01) in subcutaneous adipose tissue (SAT) of Bamei pigs at 180 d, adipocytes and stromal-vascular fraction extracted from SAT of Bamei pigs at 1 d compared with Large White pigs. Knockdown of FoxO1 increased triglyceride content (P < 0.01) and upregulated the levels of adipocyte fatty-acid binding protein, PPARγ, and CCAAT enhancer-binding protein α (C/EBPα) at 6 d after porcine preadipocytes were induced. Furthermore, the transcriptional regulation of FoxO1 through C/EBPß during early porcine preadipocyte differentiation and the effect of insulin on phosphoinositide 3 kinase (PI3K)/glycogen synthase kinase 3ß (GSK3ß) signal pathway by FoxO1 were examined. The results indicated that FoxO1 inhibited transcription activity of C/EBPß, whereas C/EBPß did not affect transcription activity of FoxO1. At 6 and 12 h of early differentiation, knockdown of FoxO1 triggered the transcription activity of C/EBPß. In addition, FoxO1 protein interacted with C/EBPß protein in porcine adipocytes at 12 h after induction. Under treatment with 100 nM insulin, knockdown or overexpression of FoxO1 mediated PI3K/GSK3ß signaling via upregulating or downregulating the levels of GSK3ß and its phosphorylation in adipocytes. Taken together, there is low, but detectable, expression of FoxO1 in SAT of obese pigs and FoxO1 inhibited adipogenesis through C/EBPß and PI3K/GSK3ß signaling pathway. These findings provide useful information to further the understanding of the function of FoxO1 in porcine adipogenesis.

Direct synthesis of heparin-like poly(ether sulfone) polymer and its blood compatibility.

In this study, heparin-like poly(ethersulfone) (HLPES) was synthesized by a combination of polycondensation and post-carboxylation methods, and was characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance hydrogen spectrum and gel permeation chromatography. Owing to the similar backbone structure, the synthesized HLPES could be directly blended with pristine PES at any ratios to prepare PES/HLPES membranes. After the introduction of HLPES, the microscopic structure of the modified PES membranes was changed, while the hydrophilicity was significantly enhanced. Bovine serum albumin and bovine serum fibrinogen adsorption, activated partial thromboplastin time, thromb time and platelet adhesion for the modified PES membranes were investigated. The results indicated that the blood compatibility of the PES/HLPES membranes was significantly improved compared with that of pristine PES membrane. For the PES/HLPES membranes, obvious decreases in platelet activation on PF-4 level, in complement activation on C3a and C5a levels, and in leukocytes activation on CD11b levels were observed compared with those for the pristine PES membrane. The improved blood compatibility of the PES/HLPES membrane might due to the existence of the hydrophilic groups (-SO3Na, -COONa). Furthermore, the modified PES membranes showed good cytocompatibility. Hepatocytes cultured on the PES/HLPES membranes presented improved growth in terms of SEM observation, MTT assay and confocal laser scanning microscope observation compared with those on the pristine PES membrane. These results indicate that the PES/HLPES membranes present great potential in blood-contact fields such as hemodialysis and bio-artificial liver supports.

Homocysteine levels and cognitive function scores measured with MMSE and BCAT of middle-aged and elderly subjects in Tianjin City.

OBJECTIVE: China is proceeding into the aging society. There are near 6 million elderly suffering senile dementia,while cognitive impairment is an important clinical feature in dementia. The factors involved in cognitive dysfunction in the middle-aged and the elderly persons were investigated. DESIGN: Cross-sectional study. SETTING: Community dwellers and nursing home residents in Tianjin, China. SUBJECTS: Total of 662 subjects(284 men and 378 women) aged 55-93. METHODS: A designed questionnaire was used to collect their demographic data, information of disease and medication, and life style. Mini-mental state examination (MMSE) and Basic Cognitive Aptitude Tests (BCAT) software were applied to evaluate their cognitive function. Serum total homocysteine (tHcy) level was quantified by enzyme conversion method. A multiple linear stepwise regression analysis was applied to find the influencing factors of cognitive function. RESULTS: The average serum tHcy concentrations was 15.95±7.29 µmol/L, while the prevalence of hyperhomocysteinemia (HHE) was 45.4%. The average serum tHcy level and prevalence of HHE were higher in men than those in women after ruling out the age differences. The mean MMSE and BCAT scores were 26.74±2.71 and 50.26±18.84 respectively. The BCAT score was negatively correlated with age and positively correlated with education. Multiple linear stepwise regression equations showed that the P value was less than 0.001, the BCAT regression equation showed that the R2=0.453. Serum tHcy concentration was negatively correlated with total scores of BCAT, digit copy, Chinese character comparison, mental arithmetic, Chinese character rotation and recall answer of mental arithmetic test. Total scores of BCAT were negatively correlated with education, inhabitancy, serum tHcy concentration and age. In addition, Chinese character rotation was correlated with tea consumption. Remembrance and recognition of dual words and nonsense figures was correlated with income level. CONCLUSIONS: Hyperhomocysteinemia is associated with cognitive impairment in the middle-aged and the elderly persons in Tianjin. The BCAT scores could well represent the detailed cognitive function in elderly and negatively correlate with age, but positively correlated with education level. Serum tHcy concentration was negatively correlated with total BCAT scores.

Developmental characteristics of pectoralis muscle in Pekin duck embryos.

To confirm the entire developmental process and transition point of embryonic Pekin duck pectoral muscle, and to investigate the association between pectoral muscle development and their regulating genes, anatomical and morphological analyses of embryonic Pekin duck skeletal muscles were performed, and the expression patterns of its regulating genes were investigated. The anatomical analysis revealed that body weight increased with age, while increases in pectoral muscle weight nearly ceased after the embryo was 20 days of hatching (E20). The developmental morphological characteristics of Pekin duck pectoral muscle at the embryonic stage showed that E20 was the transition point (from proliferation to fusion) of Pekin duck pectoral muscle. The expression patterns of MRF4, MyoG, and MSTN indicated that E19 or E20 was the fastest point of pectoral muscle development and the crucial transition for Pekin duck pectoral muscle development during the embryonic stage. Together, these findings imply that E20 is the crucial transition point (from proliferation to fusion) of Pekin duck pectoral muscle and that there is no muscle fiber hypertrophy after E20. Results of this study provide further understanding of the developmental process and transition point of Pekin duck pectoral muscle during the embryo stage.

The clinical significance of the complete type of suprapatellar membrane.

The plicae are synovial septa remaining in adult life that existed in early fetal life. The suprapatellar plica separates the suprapatellar pouch from the knee joint. The plica syndrome has clinical significance, which has been occasionally overlooked, but the pathophysiology of symptomatic plicae may be hard to explain. To evaluate the clinical significance of the suprapatellar plicae, the authors reviewed 34 cases in 23 patients with vague pain around the knee and a total septum of the suprapatellar plica at arthroscopic examination from September 1991 to December 1993. The follow-up period was from 6 months to 2 years and 9 months. The most common presenting symptom was chronic mild knee pain, aggravated by prolonged squatting or standing, with other patients reporting recurrent swelling, instability, giving-way, or a feeling of snapping. The objective findings include palpable band on the superomedial side, audible snapping, and local tenderness, but there were no significant abnormal findings in the laboratory. The radiographic findings were few, with sclerosis of the articular surface of the patella in 2(6%), malalignment in 1(3%), and mild degenerative change in 4 cases(12%). Five of 11 patients evaluated by bone scan had increased uptake around the patellofemoral joint, and 7 of 13 knees had a relatively small suprapatellar bursa on conventional arthrogram or pneumoarthrogram. At arthroscopy, a suprapatellar plicae with complete septum was identified in 30 of 34 cases (88%) and associated lesions presented as meniscal tears, loose body, and discoid meniscus without tear. The complete plicae were surgically excised under arthroscopic control in 30 patients and the results were excellent in 22 patients (73%), good in 5 (17%), and poor in 3 (10%)at 17 months follow-up; there were no failures. In our opinion, the complete suprapatellar plica is clinically significant in patients who have equivocal diagnosis of knee problems and further studies of the pathophysiology of complete suprapatellar plica are needed.

Hypoxia stimulates human preproendothelin-1 promoter activity in transgenic mice.

Significant elevations in endothelin (ET)-1 levels accompany many diseases, but the underlying regulatory mechanisms are unclear. To investigate the in vivo regulation of human preproendothelin-1 (PPET-1), we examined the activity of the PPET-1 promoter in transgenic mice exposed to hypoxia. Mice expressing one of three PPET-1 promoter-luciferase (PPET-1/LUC) reporter transgenes (approximately 2.5 kb, 138 bp, or none of the 5'-flanking sequences of the PPET-1 gene) were generated. LUC expression was reduced in mice with a truncated 138-bp PPET-1 promoter. Exposure of mice bearing the 2.5-kb PPET-1/LUC transgene to hypoxia (10% O2 for 24 h) increased LUC expression sixfold in pulmonary tissue but only twofold in other tissues. In situ hybridization revealed the strongest transgene expression in the pulmonary vasculature and bronchiolar epithelium. These data are consistent with the hypothesis that hypoxic induction of the PPET-1 gene leads to increased pulmonary production of ET-1 in diseases associated with low O2 tension.

[Foreign genes expression in rat vascular smooth muscle].

Three retroviral vectors containing report gene LacZ or the whole length cDNA of human Pro-UK and tPA, pN2-LacZ, pN2-CMV-ProUK and pN2-CMV-tPA were constructed. The rat vascular smooth muscle cells (VSMCs) were transfected with the plasmids by calcium phosphate coprecipitation or pseudovirus infection. The transfected cells were selected by G418. Southern blot analysis showed that the foreign genes were present in the genome of the transfected VSMC, and the expression products of these genes could be detected in the transfected VSMCs. These results suggested that the VSMC could be a targeting cell for gene therapy on cardiovascular diseases.

Effect of endothelin, angiotensin II and ANP on proliferation of vascular smooth muscle cells and cardiomyocytes.

By means of cell culture, 3H-thymidine (3H-TdR) incorporation and c-fos oncogene dot plotting technique, it was found that endothelin (ET) and angiotensin (ANG II) could promote proliferation and DNA synthesis of cultured vascular smooth muscle cells (VSMCs) and myocardial cells, and stimulate expression of c-fos oncogene of VSMCs. However, atrial natriuretic peptide (ANP) antagonizes the above effects of ET and ANG II.

[Effect of ANP on angiotensin II--stimulated multiplication and c-fos oncogene expression of SHR vascular smooth muscle cells].

By means of technique of cell culture, 3H-thymidine incorporation and dot blot, it was demonstrated that angiotensin II (AGT II) stimulated proliferation and c-fos oncogene expression in cultured SHR vascular smooth muscle cells (VSMC) in a dose-dependent manner. This effect of AGT II was significantly inhibited by co-incubation with ANP. The results suggest that proliferation of VSMC is regulated by some interaction between AGT II and ANP.

[Effects of microinjection of clonidine into nucleus tractus solitarii on atrial natriuretic factor in rats].

In order to study whether atrial natriuretic factor (ANF) is involved in the depressor effect of clonidine, microinjection of the latter into nucleus tractus solitarii (NTS) was carried out in anesthetized stroke-prone spontaneously hypertensive rats (SHRsp) and normotensive Wistar-Kyoto (WKY) rats. Each strain was randomly divided into three groups by injecting: (1) clonidine (1.0 microgram/0.2 microliter); (2) yohimbine (3.3 micrograms/0.2 microliter) followed by (1); (3) artificial cerebral spinal fluid (ACSF, 0.2 microliter) as control. A decrease of blood pressure and heart rate and a suppression of ANF release elicited by clonidine were significantly greater in SHRsp than in WKY rats. After blockade of alpha 2-receptor with yohimbine, the hypotensive effect of clonidine was blocked completely in WKY rats, but only partially in SHRsp, while the suppression effect on ANF release was eliminated in both strains. In addition, the decrease of plasma catecholamine produced by clonidine could also be blocked after yohimbine. The results suggest that ANF probably does not contribute to the depressor effect of centrally administered clonidine, while in SHRsp the decrease of plasma ANF might be a blood pressure-dependent compensatory response.

[Changes in atrial natriuretic peptide and vasopressin during the pressor response to central osmotic stimulation].

In order to study the mechanism of pressor response to central osmotic stimulation, rats were administered with hypertonic artificial cerebrospinal fluid (ACSF) intracerebroventricularly. Carotid arterial pressure and heart rate were recorded. Ten minutes after administration, blood samples, hypothalamus and hypophysis were taken for the determination of atrial natriuretic peptide (ANP) and vasopressin (AVP) by radioimmunoassay. The results showed that after central administration of hypertonic ACSF, the plasma level of AVP increased significantly with no apparent change in ANP. In hypothalamus and hypophysis, the content of ANP was increased while that of AVP decreased.

[Effects of human atrial natriuretic factor-(99-126) on plasma and brain vasopressin in stroke-prone spontaneously hypertensive rats].

In order to investigate the interaction between atrial natriuretic factor (ANF) and arginine vasopressin (AVP) in the pathogenesis of essential hypertension, the effects of intravenous (iv) or intracerebroventricular (icv) injection of human ANF-(99-126) on plasma and brain AVP, as well as mean arterial pressure (MAP), urinary volume (UV) and sodium (UNaV) excretion in stroke-prone spontaneously hypertensive rats (SHRsp) and age-matched normotensive Wistar-Kyoto rats (WKY) were studied. The results showed that ten minutes after iv injection of ANF, MAP decreased by 9.4% and 12.2% (P less than 0.05), UV increased about 9 and 20 folds (P less than 0.01), UNaV increased about 16 and 29 folds (P less than 0.01) in SHRsp and WKY rats, respectively. No such significant changes in these parameters were found in the icv group. Although iv and icv injection of ANF caused significant decrease of plasma AVP in both strains, the decrease was less marked in SHRsp than in WKY rats, while the maximum decreases were 58% (iv) and 31% (icv) in SHRsp, the corresponding values were 80% (iv) and 65% (icv) in WKY. Intravenous and intracerebroventricular injection of ANF also induced significant increase of hypothalamic AVP in both SHRsp and WKY rats, but no significant change could be found in hypophyseal AVP content. The results suggest that decreased sensitivity of AVP inhibition as well as less marked hypotensive, diuretic and natriuretic effects to ANF in SHRsp might play a role in the pathogenesis of their hypertension.