Biomedical subjects

Jun Xu

Publications and source records attributed to Jun Xu.

At least 73 records · Page 4Linked to original sources

PubMed2006

Pedicled deep inferior epigastric perforator flap: an alternative method to repair groin and scrotal defects.

With minimal donor-site morbidity and bulky soft tissue supply, deep inferior epigastric perforator (DIEP) flap is now a preferred free flap in reconstructive surgery. Based on the experiences in free flap procedures, the authors explored a new usage of the DIEP flap to repair groin and scrotal defects. Over the last 2 years, 8 pedicled DIEP island flaps were successfully elevated and transferred in 7 male patients. With intramuscular dissection, the pedicle length could be elongated, with minimal damage to the abdominal fascia-muscular structure. Among these flaps, 5 were used for penoscrotal restore; 3 were raised to repair groin defects. All flaps survived completely. Groin reconstruction with such a flap gave a satisfactory esthetic result. Though somewhat bulky for penoscrotal restoration, it was acceptable for elderly patients. The authors conclude that this flap can be chosen as an alternative option to deal with complex groin and scrotal wounds.

Adult↗

PubMed2006

Ultrasonic collection of small particles by a tapered metal strip.

A pi-shaped ultrasonic actuator can collect small particles by its two sharp edges. However, the collection of particles is weak in air and not very stable in water. In this paper, a refinement to the pi-shaped ultrasonic actuator is made for a more efficient collection of small particles in air and water. In the refined structure, an ultrasonic actuator with a metal strip is used to collect small particles. The metal strip is mechanically driven by one corner of a rectangular, sandwich-shaped ultrasonic transducer operating in the thickness mode vibration. The metal strip is tapered along its length and has a strong vibration at its tip. Small particles in air and water can be attracted to the radiation surface near the end of the metal strip. The dependence of the number of collected particles on driving frequency and voltage is investigated for shrimp eggs, mint seeds, and grass seeds. For a given driving voltage and particle type, the number of collected particles reaches a maximum value at some driving frequency. Increasing driving voltage increases this maximum number to some extent; but too large a driving voltage decreases it. The maximum number also depends on the weight per particle. It increases as the weight per particle decreases for the particles with close densities. Furthermore, the relationship between the number of collected particles and vibration amplitude at the end of the metal strip is investigated for shrimp eggs, mint seeds, and grass seeds. The number is approximately linearly proportional to the vibration amplitude when the vibration amplitude is not too large. In addition to the application in which the length of the metal strip is parallel to gravitation, the actuator also can be used with its length perpendicular to gravitation. However, the latter has a weaker capability of collecting small particles. It is also found that the actuator has a stronger capability to collect particles in water than in air.

Journal Article↗

PubMed2006

Highly salted food and mountain herbs elevate the risk for stomach cancer death in a rural area of Japan.

BACKGROUND: Although many case-control and experimental studies have shown that highly salted foods are risk factors for stomach cancer, only a few cohort studies have supported the relationship. METHODS: In a cohort study conducted in a rural area of Japan, 8035 residents aged over 30 years (approx. 55% were female) filled out a questionnaire. Seventy-six of them died from stomach cancer during an 11-year follow-up period. In the questionnaire, intake frequencies of 29 food items, smoking and drinking habits were investigated. Tsukemono (pickled vegetables) and tsukudani (foods deep boiled in soy sauce) are highly salted foods in the area. Frequency of each food item intake was classified into three levels, and age- and sex-adjusted risks were calculated using proportional hazard models. RESULTS: In the final model obtained by backward elimination, frequent intake of tsukemono and tsukudani and that of mountain herbs remained as significant risk factors. Compared with the least frequent intake, risk (95% confidence interval) of the most frequent intake was 5.4 (1.8-16.3) for highly salted foods (P for trend < 0.01) and 3.7 (1.4-9.6) for mountain herbs (P for trend = 0.04). CONCLUSION: Highly salted foods and mountain herbs were important risk factors for death from stomach cancer.

Adult↗

PubMed2006

EshA accentuates ppGpp accumulation and is conditionally required for antibiotic production in Streptomyces coelicolor A3(2).

Disruption of eshA, which encodes a 52-kDa protein that is produced late during the growth of Streptomyces coelicolor A3(2), resulted in elimination of actinorhodin production. In contrast, disruption of eshB, a close homologue of eshA, had no effect on antibiotic production. The eshA disruptant accumulated lower levels of ppGpp than the wild-type strain accumulated. The loss of actinorhodin production in the eshA disruptant was restored by expression of a truncated relA gene, which increased the ppGpp level to the level in the wild-type strain, indicating that the reduced ppGpp accumulation in the eshA mutant was solely responsible for the loss of antibiotic production. Antibiotic production was also restored in the eshA mutant by introducing mutations into rpoB (encoding the RNA polymerase beta subunit) that bypassed the requirement for ppGpp, which is consistent with a role for EshA in modulating ppGpp levels. EshA contains a cyclic nucleotide-binding domain that is essential for its role in triggering actinorhodin production. EshA may provide new insights and opportunities to unravel the molecular signaling events that occur during physiological differentiation in streptomycetes.

Anthraquinones↗

PubMed2006

Decreased hepatic futile cycling compensates for increased glucose disposal in the Pten heterodeficient mouse.

Despite altered regulation of insulin signaling, Pten(+/-) heterodeficient standard diet-fed mice, approximately 4 months old, exhibit normal fasting glucose and insulin levels. We report here a stable isotope flux phenotyping study of this "silent" phenotype, in which tissue-specific insulin effects in whole-body Pten(+/-)-deficient mice were dissected in vivo. Flux phenotyping showed gain of function in Pten(+/-) mice, seen as increased peripheral glucose disposal, and compensation by a metabolic feedback mechanism that 1) decreases hepatic glucose recycling via suppression of glucokinase expression in the basal state to preserve hepatic glucose production and 2) increases hepatic responsiveness in the fasted-to-fed transition. In Pten(+/-) mice, hepatic gene expression of glucokinase was 10-fold less than wild-type (Pten(+/+)) mice in the fasted state and reached Pten(+/+) values in the fed state. Glucose-6-phosphatase expression was the same for Pten(+/-) and Pten(+/+) mice in the fasted state, and its expression for Pten(+/-) was 25% of Pten(+/+) in the fed state. This study demonstrates how intra- and interorgan flux compensations can preserve glucose homeostasis (despite a specific gene defect that accelerates glucose disposal) and how flux phenotyping can dissect these tissue-specific flux compensations in mice presenting with a "silent" phenotype.

Animals↗

PubMed2006

Lipin deficiency impairs diurnal metabolic fuel switching.

Fatty liver is a common feature of both obesity and lipodystrophy, reflecting compromised adipose tissue function. The lipin-deficient fatty liver dystrophy (fld) mouse is an exception, as there is lipodystrophy without a fatty liver. Using a combination of indirect calorimetry and stable-isotope flux phenotyping, we determined that fld mice exhibit abnormal fuel utilization throughout the diurnal cycle, with increased glucose oxidation near the end of the fasting period and increased fatty acid oxidation during the feeding period. The mechanisms underlying these alterations include a twofold increase compared with wild-type mice in tissue glycogen storage during the fed state, a 40% reduction in hepatic glucose production in the fasted state, and a 27-fold increase in de novo fatty acid synthesis in liver during the fed state. Thus, the inability to store energy in adipose tissue in the fld mouse leads to a compensatory increase in glycogen storage for use during the fasting period and reliance upon hepatic fatty acid synthesis to provide fuel for peripheral tissues during the fed state. The increase in hepatic fatty acid synthesis and peripheral utilization provides a potential mechanism to ameliorate fatty liver in the fld that would otherwise occur as a consequence of adipose tissue dysfunction.

Animals↗

PubMed2006

[Application of real-time tissue elastography in diagnosis of breast cancer].

OBJECTIVE: To investigate the clinical value of real-time tissue elastography (RTE) in the diagnosis of breast cancer. METHODS: One hundred and twenty patients with breast lumps (135 lesions) were examined with B-mode imaging, color Doppler flowing imaging (CDFI) and RTE. The elastogram was graded using 5-score evaluating method. The postoperative pathological diagnosis was used as gold standard, and the sensitivity, specificity and accuracy of RTE and two-dimensional ultrasonography combined with RTE in diagnosis of breast cancer were calculated. RESULT: When the score >4 was set for cut-off criteria of malignancy, the sensitivity, specificity and accuracy of RTE was 85.45%, 83.75% and 84.4%, respectively. While two-dimensional ultrasonography combined with RTE was used, the sensitivity, specificity and accuracy increased up to 100%, 95% and 97%, respectively. CONCLUSION: RTE combined with two-dimensional ultrasonography can improve the validity in the diagnosis of malignant breast lesions.

Adolescent↗

PubMed2006

[Colocalized expression of Fas and Fas-ligand in acute pancreatitis and its correlation with cell apoptosis].

OBJECTIVE: To study the expressions of Fas and Fas-Ligand (FasL) genes in rats with acute pancreatitis (AP) and their relation to apoptosis of pancreatic acinar cells. METHODS: Rat models of acute pancreatitis with varied severity were established by retrograde injection of sodium taurocholate at different concentrations via the apancreatobiliary duct. The expressions of Fas and FasL mRNAs and proteins were detected by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. The apoptosis of acinar cells was quantified by in situ nick ending-labeling technique. RESULTS: of expressions fas, FasL mRNA and protein were colocalized in normal pancreatic acinar cells. In pancreatic tissue with less severe inflammation, the expressions of Fas and FasL mRNA increased significantly, and the apoptosis index of the acinar cells was also elevated; with the increase in the severity of the pancreatitis, the expression of Fas and FasL mRNAs were gradually lowered and apoptosis index of the acinar cells was increased. CONCLUSION: Fas/FasL system might be involved in the renewal and homeostasis of normal pancreatic tissue, and constitute an important pathway mediating the apoptosis of pancreatic acinar cells in AP.

Acute Disease↗

PubMed2006

[Changes in cyclooxygenase gene expression during spontaneous recovery from stress ulcer in rats].

OBJECTIVE: To observe the changes in gene expression of cyclooxygenase (COX) during spontaneous recovery from stress ulcer in rats exposed to water immersion and restraint stress (WRS). METHODS: A rat model of stress ulcer was established by means of WRS, in which the changes in COX expression were detected with immunohistochemistry and reverse transcription (RT)-PCR. RESULTS: Very low levels of COX-2 expression were detected in the gastric mucosa of the control rats, and the expression increased significantly during the healing process of the stress ulcer (P<0.05). COX-1 expression in the gastric mucosa showed no significant difference between the control group and the stress ulcer groups during healing (P>0.05). CONCLUSION: COX-1 and COX-2 expressions in rat gastric mucosa during the recovery from stress ulcer participate in the recovery of the damaged mucosa possibly by mediating prostaglandin secretion.

Animals↗

PubMed2006

[Analysis of coping strategies of community population in Shenzhen].

OBJECTIVE: To investigate the coping strategies of the community-based population in Shenzhen. METHODS: Totally 5,940 subjects from the communities in Shenzhen were sampled and tested with the Simplified Coping Style questionnaire. RESULTS: The most common coping strategies adopted by the community residents in Shenzhen were "consoling themselves" (33.1%) and "looking at the bright side of things" (31.4%), and the least adopted coping strategy was "relieving distress by smoking, drinking, taking medicine and eating" (57.8%); the strategies left out from their choices were mostly negative strategies. The scores for positive coping strategy factors of community residents in Shenzhen were greater than those of negative ones, with a mean difference of 0.43. The scores of both positive and negative coping strategy factors of these residents were significantly lower than those of general population in other mainland cities (P<0.001), with mean differences of 0.12 and 0.36, respectively. CONCLUSION: The community residents in Shenzhen adopt mostly positive strategies for coping with frustration, which benefit their status of self-rated health.

Adaptation, Psychological↗

PubMed2006

Down-regulation of the gax gene in smooth muscle cells of the splenic vein of portal hypertension patients.

BACKGROUND: The expression of gax, an anti-proliferative homeobox gene, is rapidly down-regulated in vascular smooth muscle cells (VSMCs) following arterial injury. Whether the down-regulation of gax is involved in modulating the proliferation of smooth muscle cells of the splenic vein in patients with portal hypertension has not yet been elucidated. The aim of this study was to investigate the expression of the mRNA of the gax gene in smooth muscle cells of the splenic vein in patients with portal hypertension. METHODS: Reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect the expression of gax mRNA and immunohistochemistry staining was performed to demonstrate the expression of PCNA protein in the splenic veins of 28 patients with portal hypertension and those of 12 normal controls. This study was approved by the Institutional Ethics Committee and informed consent was obtained from all participants. RESULTS: RT-PCR showed that the expression of gax mRNA was PCNA-positive and negative in the splenic vein of patients with portal hypertension (1.08+/-0.04 and 1.39+/-0.27, respectively). There was a significant difference in the 28 patients compared with the 12 normal controls (P<0.01). The relative expression of PCNA protein in the vascular tissues was significantly higher in the experimental group than in the control group. CONCLUSIONS: Down-regulation of gax mRNA and the overexpression of PCNA protein were seen in smooth muscle cells of the splenic vein in patients with portal hypertension, regulating the proliferation, migration and phenotypic change and resulting in remodelling of the splenic vein, which may play an important role in the pathogenesis and maintenance of portal hypertension.

Adult↗

PubMed2006

[Clinical experiences of breast reconstruction using deep inferior epigastric perforator flaps].

OBJECTIVE: To summarize the experiences of the breast reconstruction using the deep inferior epigastric perforator (DIEP) flaps. METHODS: From March 2000 to March 2005, 18 cases of breast defects were treated. Defect was caused by mammary cancer in 17 cases and by Poland's syndrome in 1 case. Preoperative radiotherapy was given in 7 patients. The size of the chest wall defects ranged from 25 cm X 20 cm to 12 cm X 8 cm. All the breasts were reconstructed with the DIEP flaps. The flap size ranged from 35 cm X 22 cm to 12 cm X 8 cm (mean 9.58 cm X 26.85 cm). The internal mammary vessels were used as the recipient vessels in 15 patients who underwent delayed breast reconstruction. Among these cases, the bilateral deep inferior epigastric vessels were anastomosed with the proximal and distal ends of the internal mammary vessels separately in 13 cases and only unilateral deep inferior epigastric vessels were harvested and anastomosed to the proximal ends of the internal mammary vessels in 2 cases. The recipient vessels were the thoracodorsal vessels and thoracodorsal vessels plus the circumflex scapular vessels in the patients who underwent immediate breast reconstruction. RESULTS: Sixteen flaps survived completely postoperatively and the survival rate was 89%. Flap necrosis occurred in 2 patients; one underwent radiotherapy preoperatively while the other did not. The distal 1/3 portion of the flap necrosed in the patient with Poland's syndrome. Nipple reconstruction and breast remolding were performed in 2 patients. Partial dehiscence of the median abdominal incision occurred in 2 patients at 2 weeks postoperatively and were repaired with resuturing and split-thickness skin grafting separately. CONCLUSION: Breast reconstruction using the DIEP flaps not only can preserve the advantages of the traditional method using the transverse rectus abdominis myocutaneous flaps, but also can retain the maximal function of the rectus abdominal muscle and prevent the occurrence of abdominal weakness and hernia. It is an ideal method of the breast reconstruction.

Adult↗

PubMed2006

[Changes of expression of the P38 MAPK and caspase-3 in rat retinal ischemia-reperfusion model and the influence of Nimodipine].

OBJECTIVE: To investigate the protective effects of L-type calcium blocker Nimodipine on retinal ischemia-reperfusion of rat and its affect on cell signal transduction system. METHOD: Ninety-five Wistar rats were divided into 4 groups randomly. Group A was normal (blank) control group and included 5 rats; Group B was retinal ischemia-reperfusion (experimental control) group which had 30 rats; Group C was retinal ischemia-reperfusion plus Nimodipine (experimental) group that included 30 rats; and group D was low-pressure irrigation (pseudo-operation) group that had 30 rats. The rat retinal ischemia-reperfusion model was prepared by elevate the pressure of anterior chamber to 110 mm Hg. Five rats were executed at 2, 6, 12, 24 and 72 hours after reperfusion. The specimens were embedded in paraffin, the expression of P38 MAPK and caspase-3 in the retina was evaluated by in situ hybridization and immunohistochemical studies on every time point, respectively. The results were analyzed by Metamorph software, take the average optical density (A) to perform statistical analyses. RESULTS: After retinal ischemia-reperfusion, the expression of P38 MAPK mRNA and caspase-3 were increased. The in situ hybridization signal of P38 was located in retinal ganglion cell layer and inner nuclear layer, there was only little expression in normal retina. In group B, P38 expression increased 6 hours after reperfusion, reached its peak after 12 hours, continued to 24 hour, decreased gradually after 72 hours. In group C, after Nimodipine medication, the expression trend of P38 was similar to group B, but the expression level was lower. Statistical analyze using average optical density as parameter indicated that the difference of expression of P38 MAPK at 6, 12, 24 and 72 hours was statistical significant (P < 0.05) between group B and C, group B and A, group C and A and D. The expression of caspase-3 was similar to that of P38. Two hours after reperfusion, there were scattering positive nucleus in inner nuclear layer; 6 hours later, positive nucleus were located in ganglion cell layer and inner nuclear layer, and reached its peak after 24 hours. In group C, the expression trend of caspase-3 was similar to that of group B, but had less positive cells and showed lighter staining. CONCLUSION: Both P38 MAPK and caspase-3 participate in signal transduction of retinal neurons during retinal ischemia-reperfusion. Nimodipine can protect the retina by means of down-regulate P38 MAPK and caspase-3 expression.

Animals↗

PubMed2006

[Self-rated health status of pregnant and postpartum women].

OBJECTIVE: To To understand the self-rated health of pregnant and postpartum women. METHODS: Using Self-rated Health Measurement Scale Version 1.0 (SRHMS V1.0), health status of 50 reproductive-age nonpregnant women and 55 pregnant women on days 7 and 42 after delivery was assessed. RESULTS: There was statistic significance in daily physical activities, physical mobility and total score of physical health subscale between pregnant women and reproductive-age nonpregnant women (P<0.01). Statistical significance was also found in daily physical activities, physical mobility and total score of physical health subscale as well as total score of the SRHMS V1.0 between women before and 7 days after delivery (P<0.01). The scores of physical mobility, total score of physical health subscale and total score of SRHMS V1.0 showed significant difference between women before and 42 days after delivery (P<0.01). CONCLUSION: Although the physical health status of pregnant women is generally poorer than that of the reproductive-age nonpregnant women, their self-rated health show no significant differences. The self-rated health status of women 7 days after delivery is worse than that before delivery, while such status on days 42 after delivery is obviously better than that before delivery. SRHMS V1.0 provides an effective means for health evaluation of perinatal and postpartum women.

Adult↗

PubMed2006

[Follow-up examination for newborns and infants who failed hearing screening].

OBJECTIVE: To investigate the hearing change and the characteristic of hearing thresholds of the infants failing in the hearing screening. METHOD: ABR,DPOAE and acoustic immittance were used to test infants failing in the screening in their third month and the sixth month, whose results were compared. RESULT: In the third month the false positive rate of DPOAE test was 9.6%. Comparing with the results tested in the third month, the degree of severe hearing loss retested in the sixth month did not change much. But the percentage of the slight-moderate hearing loss improvement to normal or better was higher. Comparing ABR threshold result in the third month and that in the sixth month, t = 3.496, P <0.01 in the left ear, and t = 5.572, P <0.01 in the right ear, respectively. There was significant difference between these results. CONCLUSION: The new-borns failing DPOAE can not be just considered to identifying hearing loss,and it must be with the ABR to make the diagnosis. It is feasible to diagnose severe-profound hearing loss in the third month and interfere before the sixth month, but the infants with mild-moderate hearing loss must undertake the auditory tests more than twice and be followed up in more than half a year, then we can make diagnosis according to the audiologic evaluations results and the daily behaviors.

Auditory Threshold↗

PubMed2006

[Prediction of the possible tertiary structure alterations of p53 protein following point mutation in p53 gene condon 282 in lung cancer cells].

This study was carried out to predict the possible tertiary structure alterations of p53 protein after point mutation of p53 gene condon 282 in lung cancer cells based on the latest 3D structure analysis platform series of Phyre software. It was found that the p53 gene condon 282 mutation (Arg/Leu) may destabilize the H2 helix and DNA binding in the major groove by compromising the contacts of p53 protein with the beta-hairpin of DNA binding surface.

Amino Acid Sequence↗

PubMed2006

[Study on the acryl amide intake in the Beijing diet].

OBJECTIVE: A 24-hours recall study was performed to get the acryl amide intake in the Beijing diet. METHODS: 24 separate items bought in the Beijing Market were analyzed and 2460 diet lists (820 participants x 3 days) were calculated. RESULTS: The following mean intakes of acryl amide have been estimated (microg/dm): males 18.6, females 16.6. For the 97.5 percentile of the population the intake is estimated to: males 59.0, females 50.4. As dose calculated per kg bodyweight the mean intake becomes [microg/(kg bw x d)]: males 0.282, females 0.284. For the 97.5 percentile [microg/ (kg bw x d)]: males 0.898, females 1.007. The contribution of the different meals and to the intake was as follows: breakfast 20.48%, lunch 38.99%, dinner 39.42%, snacks 1.17%. CONCLUSION: The survey leads to the conclusion that lunch and dinner are significant sources of acryl amide in a typical Beijing diet even if they have relatively low levels of acryl amide. Chinese traditional breakfast food is also an important source of acryl amide in a typical Beijing.

Acrylamide↗

PubMed2006

[The possible mechanism of lung injury induced by severe acute respiratory syndrome coronavirus spike glycoprotein].

OBJECTIVE: To investigate the role of severe acute respiratory syndrome coronavirus (SARS-CoV) in the induction of acute lung injury by promoting the synthesis of chemokine/cytokines in human endothelial cells. METHODS: Twenty-three SARS patients were enrolled in this study, comprising 15 male and 8 female, aged 27 - 55 years, mean (36 +/- 6) years. They were treated at Guangzhou Institute of Respiratory Disease from February to May in 2003. Chemokines/cytokines in the blood of patients with SARS were dynamically screened by liquid chip system. The lung was studied histopathologically using immunohistochemical technique. Spike glycoprotein of SARS-CoV was recombined by using insect-baculovirus expression system and Nickel affinity Magnet Beads, and then used to stimulate cultured human umbilical vein endothelial cells (HUVEC). Morphological changes of HUVEC were observed by microscope. Levels of chemokines/cytokines involved in immunoreaction in response to virus infection were detected in the supernatants of those cells cultured with the Spike glycoprotein by liquid chip system. RESULTS: Interferon-gamma inducible protein 10 (IP-10) was markedly elevated in the blood during the early stage of SARS [(7,600 +/- 2,400) ng/L, P < 0.01], and remained at a high level in the progressive stage [(8,100 +/- 2,300) ng/L, P < 0.01] and the end stage [(8,000 +/- 2,800) ng/L, P < 0.01] until convalescence [(1,250 +/- 450) ng/L, P > 0.05]. Moreover, IP-10 was highly expressed in the lung. Vacuoles appeared in part of HUVEC after Spike glycoprotein stimulation. As time going on, the HUVEC turned to be round in shape and even disrupted. Under normal condition, no detectable IP-10 was found in HUVEC. A high level of IP-10 [(179 +/- 34), (889 +/- 212), (1,676 +/- 199) ng/L, all P < 0.05] was detected in the HUVEC 12 h after Spike glycoprotein (5, 20, 40 mg/L) stimulation respectively, and presented with a significant dose-dependent response. CONCLUSIONS: (1) A significant increase of IP-10 activity in the blood was found in patients with SARS-CoV infection, and remained at a high level until the stage of convalescence. A strong IP-10 protein expression was also found in SARS-CoV infected lung in autopsy. (2) The Spike glycoprotein of SARS-CoV induced a high level of IP-10 in endothelial cells, which in turn damaged endothelial cells. (3) The Spike glycoprotein of SARS-CoV induced IP-10 production by a way independent of IFN-gamma.

Adult↗