Effect of intensity clamping on laser ablation by intense femtosecond laser pulses

We have experimentally demonstrated that because of intensity clamping, when the laser peak power is higher than the critical power for self-focusing, further increase of the laser power cannot result in corresponding increase of the laser ablation rate of a metallic sample placed in gases. The ablation rate will finally approach a stabilized value. Also, the experimental technique implemented in our work could be potentially used to measure the self-focusing critical power and the nonlinear refractive index.

Effect of supervised exercise intervention on metabolic risk factors and physical fitness in Chinese obese children in early puberty

The aim of this paper was to study the effect of long-term supervised exercise-induced weight maintenance on metabolic risk factors and physical fitness in obese children in early puberty. A total of 49 obese children aged 12-14 years were divided into control and exercise groups. The children in the exercise group accepted exercise intervention supervised by a professional sports teacher for 9 of the 12 months. All participants in both groups received health education once every 3 months. Anthropometry and fasting serum lipids, glucose, insulin and homeostatic model assessment for insulin resistance (HOMA-IR) were measured at months 0, 3, 9, 12 of the intervention. Physical fitness was determined before and after intervention. After the intervention (i) BMI was reduced by 0.6 (P < 0.05) in the exercise group, but increased by 0.5 (P < 0.05) in the control group, compared with the pre-intervention level at the end of 9-month intervention; (ii) Triglyceride levels in the exercise group significantly decreased by 23.1% by 3 months (P < 0.05), and by 30.2% after 9 months (P < 0.05), but increased by 50% (P < 0.05) in the control group; high density lipoprotein-cholesterol (HDL-C) decreased more by 35% (P < 0.05) in the controls than in the exercise group (P < 0.05); (iii) Fasting serum glucose, insulin level and HOMA-IR decreased, respectively, by 23.1%, 36.6% and 48.5% in the exercise group at 9 months (P < 0.05), whereas glucose levels increased by 10.9% (P < 0.05) in the control group; (iv) Exercise performance, such as upper- and lower-limb strength, flexibility and endurance, were enhanced by 17.9%, 12.3%, 22.3% and 20.4% (P < 0.01), respectively and (v) At 12 months, i.e. 3 months after terminating the supervised exercise, serum triglycerides, glucose, insulin and HOMA-IR level all returned to the pre-intervention level. Supervised decrement exercise can effectively slow the progress of obesity, improve insulin sensitivity and metabolic risk factors, but once the supervised exercise is stopped, the health benefits weaken or vanish. The key to helping these obese children is for them to cultivate good exercise habits which are sustained throughout their lives.

Possible role of hydrogen sulfide on the preservation of donor rat hearts

OBJECTIVE

The aim of this study was to observe the preservative effect of hydrogen sulfide (H2S) on donor rat hearts.

MATERIALS AND METHODS

The hearts of 24 Sprague-Dawley rats were perfused on a Langendorff perfusion column for 30 minutes. We calculated and recorded the left ventricular-developed pressure (LVDP), and positive and negative derivatives of left ventricular systolic pressure (LVSP; +dP/dt and -dP/dt). Hearts were then arrested and stored for 6 hours at 4 degrees C: group 1, Krebs-Henseleit (KH) solution; group 2, KH solution with 1 micromol/L NaHS; group 3, KH solution with 1 micromol/L NaHS and 10 micromol/L glibenclamide; group 4, St. Thomas II solution. Hearts were transferred back to the Langendorff column. After stabilizing for 30 minutes, LV performance was assessed as before. The donor hearts were kept for pathological study including myocardial water ratio, ATP content, and myocyte apoptosis index.

RESULTS

The recovery rates of +dp/dtmax, -dp/dtmax, and LVDP of groups 2 and 4 were much better than those of groups 1 and 3. The hearts contracted immediately after reperfusion in group 4. Ventricular fibrillation was seen before contraction in the other 3 groups, with the longest duration in group. No significant difference in myocardial water ratio was found. The ATP content was the highest in group 2. Apoptosis was observed in the 4 groups with the lowest apoptosis index in group 2.

CONCLUSIONS

H2S has a protective effect on rat donor hearts at the concentration of 1 micromol/L. The protective effect is better than that of St. Thomas II solution. The protective effect of H2S can be blocked by glibenclamide.

A guanylyl cyclase-like gene is associated with Gibberella ear rot resistance in maize (Zea mays L.)

Gibberella ear rot, caused by the fungal pathogen Fusarium graminearum Schwabe, is a serious disease of maize (Zea mays L.) grown in northern climates. The infected maize grain contains toxins that are very harmful to livestock and humans. A maize gene that encodes a putative 267-amino acid guanylyl cyclase-like protein (ZmGC1) was characterized and shown to be associated with resistance to this disease. The putative ZmGC1 amino acid sequence is 53% identical and 65% similar to AtGC1, an Arabidopsis guanylyl cyclase. The Zmgc1 coding sequence is nearly identical in a Gibberella ear rot-resistant line (CO387) and a susceptible line (CG62) but several nucleotide sequence differences were observed in the UTRs and introns of the two alleles. Using a 463 bp probe derived from the CG62 allele of Zmgc1 and a recombinant inbred (RI) mapping population developed from a CG62 x CO387 cross, six Zmgc1 restriction fragment length polymorphism (RFLP) fragments (ER1_1, ER1_2, ER1_3, ER1_4, ER1_5, and ER5_1) were mapped on maize chromosomes 2, 3, 7, and 8. Markers ER1_1 and ER5_1 on chromosomes 7 and 8, respectively, were significantly associated with Gibberella ear rot resistance, each in three different environments. The amount of Zmgc1 transcript in ear tissues increased more quickly and to a greater extent in the resistant genotype compared to the susceptible genotype after inoculation with F. graminearum. Zmgc1 is the first guanylyl cyclase gene characterized in maize and the first gene found to be associated with Gibberella ear rot resistance in this plant.

CCDC134, a novel secretory protein, inhibits activation of ERK and JNK, but not p38 MAPK

In this study, we report a novel gene, CCDC134 (coiled-coil domain containing 134), that encodes a secretory protein that can inhibit the MAPK pathway as a novel human MAPK-regulating protein. The CCDC134 mRNA contains 1280 nucleotides, encoding a protein of 229 amino acids. CCDC134 is a classical secretory protein. Expression profile analysis by Northern blot, RT-PCR, immunohistochemistry and Western blot reveals that CCDC134 is widely expressed in normal adult tissues, tumor tissues and cell lines. Functional investigation reveals that overexpression of CCDC134 and its purified protein significantly inhibit transcriptional activity of Elk1 and phosphorylation of Erk and JNK/SAPK but not p38 MAPK. Conversely, specific siRNA against CCDC134 activates Elk1 transcriptional activity and promotes Erk and JNK/SAPK phosphorylation. These results clearly indicate that CCDC134 is a novel member of the secretory family and down-regulates the Raf-1/MEK/ERK and JNK/ SAPK pathways.

Assessment of the effects of subthalamic stimulation in Parkinson disease patients by artificial neural network

This study aims at applying an artificial neural network for the evaluation of the effects of deep brain stimulation (DBS) of the subthalamic nucleus (STN) on Parkinson disease (PD) patients with and without medication. A sample of 15 PD patients who have undergone STN DBS were evaluated under four test conditions: medication off and stimulation off (mof-sof), medication off and stimulation on (mof-son), medication on and stimulation off (mon-sof) and medication on and stimulation on (mon-son). A control group with 30 subjects was also evaluated. Principal component analysis (PCA) was applied on vertical ground reaction force (vGRF) and the first six principal component scores (PC score) were obtained in both groups. Those PCs scores were used as input in a probabilistic neural network (PNN). PNN presented satisfactory classification performance in the separation of controls and PD with 90.1% accuracy, 69.2% sensitivity and 100% specificity. The stimulation mof-son and mon-son conditions presented better results compared to mon-sof. In the mof-son condition, 41.7% were classified as normal, while further enhancement (63.3%) was given by the mon-son condition. These results indicated the potentiality of PNN to quantitatively evaluate treatment effects. Furthermore, STN DBS shows improvement on vGRF pattern in PD patients, most substantially when used with medication.

Potential of a novel polysaccharide preparation (GLPP) from Anhui-grown Ganoderma lucidum in tumor treatment and immunostimulation

Growing evidence indicates the potential of developing novel polysaccharide-based adjuvant for tumor therapy from edible mushrooms, including Ganoderma lucidum. In the present study, a novel polysaccharide preparation (GLPP) was isolated from the fruiting body of G. lucidum grown in Anhui, China, and characterized for its physicochemical properties. GLPP had an average molecular weight of 6600 and a specific optical rotation of +25.6 degrees , contained 10.6% protein, and had a molar ratio of 0.9:15:1 for mannose, glucose, and galactose, respectively. GLPP was also investigated and compared with PSP (polysaccharopeptide preparation), a commercial antitumor and immunostimulating agent, for its antitumor and immunostimulation capacity, and potential in reducing the toxic effects induced by cyclophosphamide (Cy) treatment and Cobalt-60 ((60)Co) radiation in mice. GLPP at levels of 100 and 300 mg/kg body weight (BW)/d significantly inhibited the growth of inoculated S(180), Heps, and EAC tumor cells in mice. GLPP at a dose of 300 mg/kg BW/d showed stronger growth inhibition against all 3 tested tumor cells than PSP at 1 g/kg BW/d. GLPP also dose-dependently increased phagocytic index, phagocytic coefficient, and 50% hemolysin value in the EAC tumor-bearing mice, indicating its potential immunostimulating property. In addition, GLPP at 300 mg/kg BW/d was comparable to PSP at 1000 mg/kg BW/d in preventing the decrease of thymus index, spleen index, white blood cells, and bone marrow karyote numbers induced by Cy treatment and (60)Co radiation. These data demonstrated the potential utilization of GLPP as an adjuvant to conventional treatments of cancers and its use for cancer prevention.

Neuroepithelial stem cells differentiate into neuronal phenotypes and improve intestinal motility recovery after transplantation in the aganglionic colon of the rat

The purpose of this study was to elucidate the possibility and the biological significance of intracolonic grafting of neuroepithelial stem cells (NESCs) as a therapeutic strategy for neuronal replacement in disorders of the enteric nervous system (ENS) such as aganglionosis. The enteric plexus of rat colon were eliminated by serosal application of the cationic surfactant benzalkonium chloride. NESCs were harvested from the neural tube of embryonic rat, labelled with bromodeoxyuridine (BrdU), and transplanted into the denervated colon. After 2, 4 and 8 weeks, grafted cells were visualized in colon sections by fluorescent double-staining for BrdU and neuronal, astrocytic, neurochemical or stem cell markers. Eight weeks post-transplantation, the intestinal motility was assessed by measuring the changes of intraluminal pressure responding to inflating stimulation and the responses to electrical field stimulation (EFS). Our results indicate that when transplanted into the denervated gut, NESCs survived and could differentiate into neurons and glial cells in vivo. Furthermore, inflation stimulated contraction and EFS-induced response were observed in NESCs grafted group compared with no reaction in denervated group. Therefore, NESCs can survive and function in the denervated rat colon in vivo, which indicates that NESCs provide a promising cellular replacement candidate for ENS.

Distinct phosphorylation sites in the SST2A somatostatin receptor control internalization, desensitization, and arrestin binding

The somatostatin subtype 2A (sst2A) receptor, a member of the G protein-coupled receptor superfamily, mediates many of the neuroendocrine and neuromodulatory actions of somatostatin, and it represents the primary target for somatostatin analogs used in cancer therapy and tumor localization. Agonist stimulation leads to the rapid phosphorylation, endocytosis, and desensitization of the sst2A receptor; however, little is known about the role of phosphorylation in sst2A regulation. sst2A phosphorylation occurs on serine and threonine residues in the third intracellular loop and carboxyl terminus. Therefore, we generated mutant receptors in which serine (Ser-), threonine (Thr-), or both (Ser-/Thr-) residues in these regions were mutated to alanine. In contrast to the wild-type receptor, somatostatin treatment did not stimulate the phosphorylation of the Ser-/Thr- mutant, and it did not produce desensitization. Furthermore, internalization of the Ser-/Thr- mutant occurred 5 times more slowly than with the wild-type receptor. Mutating only the Ser residues did not inhibit either internalization or desensitization. In contrast, mutating only the Thr residues inhibited receptor endocytosis to the same extent as in the full mutant, but it did not affect receptor desensitization. In both the wild-type and Ser- receptors, agonist binding produced a stable arrestin-receptor complex that was maintained during receptor trafficking, whereas arrestin was not recruited to either the Thr- or the Ser-/Thr- receptors. These results demonstrate that agonist-stimulated receptor phosphorylation is necessary for both desensitization and rapid internalization of the sst2A receptor. However, sst2A receptor internalization and uncoupling can occur independently, involve different receptor phosphorylation sites, and exhibit different requirements for stable arrestin association.

Renal pathological change in patients with type 2 diabetes is not always diabetic nephropathy: a report of 52 cases

AIMS

The present study examined the relationship between clinical features and renal histological changes in the Type 2-diabetic patients and evaluated the usefulness of renal biopsy in the diagnosis of diabetic versus non-diabetic kidney disease.

METHODS

52 patients with Type 2-diabetic mellitus were retrospectively analyzed for differential clinical, laboratory features and pathological characteristics including overt proteinuria (> 0.5 g/day), elevated serum creatinine and/or the development of hematuria.

RESULTS

Of 52 patients, 20 cases (38.5%) showed no detectable diabetic lesions and, thus, were diagnosed as non-diabetic renal disease (NDRD), while 32 patients (61.5%) exhibited diabetic nephropathy. Interestingly, while 29 patients showed diabetic nephropathy (DN) alone, NDRD was also found in 3 patients with DN. Clinically, 24 out of 52 patients (46.16%) had a diagnosis consistent with the pathological findings, while 10 (19.23%) were diagnosed incorrectly. Compared to NDRD patients, patients with DN had prolonged diabetic history with or without retinopathy, while 25% of patients with NDRD exhibited mesangial proliferative glomerulonephritis.

CONCLUSIONS

NDRD was a common feature in Type 2-diabetic patients with renal involvement. The absence of retinopathy and short periods of diabetic history may be useful indicators for diagnosis of NDRD clinically.

A comparison of the mechanical and structural properties of fibrin fibers with other protein fibers

In the past few years a great deal of progress has been made in studying the mechanical and structural properties of biological protein fibers. Here, we compare and review the stiffness (Young's modulus, E) and breaking strain (also called rupture strain or extensibility, epsilon(max)) of numerous biological protein fibers in light of the recently reported mechanical properties of fibrin fibers. Emphasis is also placed on the structural features and molecular mechanisms that endow biological protein fibers with their respective mechanical properties. Generally, stiff biological protein fibers have a Young's modulus on the order of a few Gigapascal and are not very extensible (epsilon(max) < 20%). They also display a very regular arrangement of their monomeric units. Soft biological protein fibers have a Young's modulus on the order of a few Megapascal and are very extensible (epsilon(max) > 100%). These soft, extensible fibers employ a variety of molecular mechanisms, such as extending amorphous regions or unfolding protein domains, to accommodate large strains. We conclude our review by proposing a novel model of how fibrin fibers might achieve their extremely large extensibility, despite the regular arrangement of the monomeric fibrin units within a fiber. We propose that fibrin fibers accommodate large strains by two major mechanisms: (1) an alpha-helix to beta-strand conversion of the coiled coils; (2) a partial unfolding of the globular C-terminal domain of the gamma-chain.

Apolipoprotein A-I stimulates AMP-activated protein kinase and improves glucose metabolism

AIMS/HYPOTHESIS

In humans, one of the hallmarks of type 2 diabetes is a reduced plasma concentration of HDL and its major protein component, apolipoprotein A-I (APOA-I). However, it is unknown whether APOA-I directly protects against diabetes. The aim of this study was to characterise the functional role of APOA-I in glucose homeostasis.

METHODS

The effects of APOA-I on phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC), glucose uptake and endocytosis were analysed in C2C12 myocytes. Glucose metabolism was investigated in Apoa-I knockout (Apoa-I (-/-)) mice.

RESULTS

APOA-I was able to stimulate the phosphorylation of AMPK and ACC, and elevated glucose uptake in C2C12 myocytes. APOA-I could be endocytosed into C2C12 myotubes through a clathrin-dependent endocytotic process. Inhibition of endocytosis abrogated APOA-I-stimulated AMPK phosphorylation. In Apoa-I (-/-) mice, AMPK phosphorylation was reduced in skeletal muscle and liver, and expression of gluconeogenic enzymes was increased in liver. In addition, the Apoa-I (-/-) mice had increased fat content and compromised glucose tolerance.

CONCLUSIONS/INTERPRETATION

Our data indicate that APOA-I has a protective effect against diabetes via activation of AMPK. ApoA-I deletion in the mouse led to increased fat mass and impaired glucose tolerance.

Laparoscopic excision of extraprostatic ejaculatory duct cyst

Our experiences with laparoscopic excisions of symptomatic extraprostatic ejaculatory duct cysts (EDCs) are reported. Three laparoscopic excisions of extraprostatic EDCs performed by one urologist in 2003 and 2004 were retrospectively reviewed. Investigations included history, physical examination, image analysis, semen analysis, operation time, estimated blood loss, time of post-operative hospital stay, recovery time for regular activities, sexual function and complications. The laparoscopic excisions of EDCs were successful. The mean operation time was 105 min, and the mean estimated blood loss was 65 ml. The average post-operative hospital stay was 3.0 days. All patients exhibited normal erection and normal ejaculation. Improvement in semen quality was observed in two patients. All patients remained free of symptoms, and recurrence of EDCs was not detected on transrectal ultrasonography over a mean 32-month follow-up period. It is concluded that laparoscopic excision of an EDC is feasible and effective. Due to minimal invasiveness, short post-operative hospitalisation and rapid recovery, laparoscopic surgery is an attractive approach to managing symptomatic EDCs, especially for sizeable cysts or those including calculus.

Magnetic studies of a syn-anti triatomic carboxylate-bridging chainlike copper(II) complex exhibiting ferromagnetic exchange

The magnetic properties of triatomic syn-anti carboxylate bridging copper(II) complex, {[Cu(2,2'-bipydine)(maleate)].2H2O}infinity (complex 1), were investigated experimentally and theoretically, suggesting weak ferromagnetic intrachain interaction. The magnetic data were analyzed and interpreted in terms of Heisenberg chain model corrected by a mean molecular field. Fitting parameters obtained for J, g, and zJ' are 3.14 cm(-1), 2.08, and -0.13, respectively. Density functional theory with generalized gradient approximation was applied to calculate the electronic structure and spin distribution of the present complex. The structural and electronic factors controlling the magnetic interactions were also determined. Ferromagnetic intrachain interactions through triatomic syn-anti carboxylate bridge result from nonplanarity of the bridging network, the exchange pathway involving both the sigma and pi orbitals of the carboxylate bridge and the spin delocalization of each magnetic orbital on the atoms of the carboxylate bridge from the copper(II) centers.