[Risk factors for delayed gastric emptying after laparoscopic pancreaticoduodenectomy: a single-center experience of 1 000 cases].

Objective: To explore the causes and summarize the treatment experience for clinically relevant delayed gastric emptying(DGE) after laparoscopic pancreaticoduodenectomy(LPD). Methods: The clinical data of 1 000 patients who underwent LPD in the Department of Liver Transplantation and Hepatobiliary Surgery,Shandong Provincial Hospital Affiliated to Shandong First Medical University between March 2017 and September 2022 was retrospectively collected. There were 640 males and 360 females,with an age of (60.1±11.4)years(range: 13 to 93 years),and 590 patients were older than 60 years. Depending on the severity of DGE,patients were divided into a clinically relevant DGE group and a 0/A grade DGE group. The comparison between the two groups was performed by the χ2 test,Fisher's exact probability method,t test or the rank sum test,and the effects of various treatment strategies for clinically relevant DGE were evaluated. Results: LPD was conducted successfully in all 1 000 patients,with a surgical time of (344.8±103.6)minutes(range:160 to 450 minutes) and intraoperative blood loss (M(IQR)) of 100 (150) ml(range:50 to 1 000 ml). A total of 74 patients(7.4%) developed clinically relevant DGE. Compared to those in the 0/A grade DGE group,patients in the clinically relevant DGE group had a higher preoperative body mass index of ((24.9±3.5)kg/m2 vs. (23.9±3.3)kg/m2,t=-2.419,P=0.016),more postoperative bile leakage(51.4%(38/74) vs. 10.8%(100/926)),pancreatic fistula(59.5%(44/74) vs. 22.9%(212/926)),abdominal infection(74.3%(55/74) vs.14.6%(135/926)),and abdominal bleeding(43.2%(32/74) vs. 11.3%(105/926))(all P<0.05). Among these patients,10 cases(13.5%) received enteral nutrition treatment,22 cases(29.7%) received parenteral nutrition treatment,and 42 cases(56.8%) received a combination of enteral and parenteral nutrition treatment. The time for patients to return to a normal diet was 21(14)days (range: 8 to 85 days). Compared to those who received only enteral(23.5(27.0)days) or parenteral nutrition treatment(15.5(11.0)days),patients who received a combination of enteral and parenteral nutrition treatment(25.5(31.0)days) had a longer time to return to a normal diet (Z=20.019,P<0.01). Among the 60 patients who developed secondary DGE,48 cases(80.0%) received ultrasound-guided puncture and drainage treatment,while 12 cases(20.0%) only received anti-infection treatment. The patients in the non-puncture drainage group had a longer time to return to a normal diet than those in the puncture drainage group (26.5(12.5)days vs. 20.0(11.0)days, Z=-2.369,P=0.018). Conclusions: Patients with clinically relevant DGE after LPD had a higher proportion of postoperative complications such as pancreatic fistula,biliary fistula and abdominal infection. A combination of enteral and parenteral nutrition treatment is needed for patients with a long-term course of DGE."Smooth" drainage and ani-infectious therapy could contribute to the recovery of DGE.

Effects of dietary niacinamide and CP concentrations on the nitrogen excretion, growth performance, and meat quality of pigs.

Reducing the dietary CP concentration in the formulation of low-protein diets without adverse effects on animal growth performance and meat quality remains challenging. In this study, we investigated the effects of nicotinamide (NAM) on the nitrogen excretion, growth performance, and meat quality of growing-finishing pigs fed low-protein diets. To measure the nitrogen balance, we conducted two trials: in nitrogen balance trial 1, four crossbred (Duroc × Landrace × Large White) barrows (40 ± 0.5 kg BW) were used in a 4 × 4 Latin square design with four diets and periods. The diets consisted of a basal diet + 30 mg/kg NAM (a control dose), basal diet + 90 mg/kg NAM, basal diet + 210 mg/kg NAM, and basal diet + 360 mg/kg NAM. In nitrogen balance trial 2, another four barrows (40 ± 0.5 kg BW) were used in a 4 × 4 Latin square design. The diets consisted of a basal diet + including 30 mg/kg NAM (control), basal diet + 360 mg/kg NAM, low-protein diet + 30 mg/kg NAM, and low-protein diet + 360 mg/kg NAM. To measure growth performance, two trials were conducted. In growth performance trial 1, 40 barrows (37.0 ± 1.0 kg) were randomly allocated to one of four dietary treatments (n = 10 per group), whereas in growth performance trial 2, 300 barrows (41.4 ± 2.0 kg) were randomly allocated to one of four dietary treatments, with each dietary treatment conducted in five repetitions with 15 pigs each. The four diets in the two growth performance trials were similar to those in nitrogen balance trial 2. Supplementing the diet with 210 or 360 mg/kg NAM reduced urinary nitrogen excretion and total nitrogen excretion and increased nitrogen retention comparted with the control diet (P < 0.05). Compared with the control diet, the low-protein diet with 360 mg/kg NAM reduced faecal, urinary, and total nitrogen excretion (P < 0.05) without affecting nitrogen retention and average daily gain (P > 0.05). Pigs fed the low-protein diet with 360 mg/kg NAM showed a decreased intramuscular fat content in the longissimus thoracis muscle when compared with pigs fed the control diet (P > 0.05). Our results suggest NAM as a suitable dietary additive to reduce dietary CP concentration, maximise nitrogen retention and growth performance, and decrease fat deposition in pigs.

[Safety and feasibility of intrathoracic modified overlap esophagojejunostomy in laparoscopic radical resection of Siewert type â ¡ adenocarcinoma of esophagogastric junction].

Objective: The study aimed to investigate the safety and feasibility of intrathoracic modified overlap method in laparoscopic radical resection of Siewert type II adenocarcinoma of the esophagogastric junction (AEG). Methods: A descriptive case series study was conducted. The clinical data of 27 patients with Siewert type II AEG who underwent transthoracic single-port assisted laparoscopic total gastrectomy and intrathoracic modified overlap esophagojejunostomy in Guangdong Provincial Hospital of Chinese Medicine from May 2017 to December 2020 were retrospectively analyzed. The intrathoracic modified overlap esophagojejunostomy was performed as follows: (1) The Roux-en-Y loop was made; (2) The jejunum side was prepared extraperitoneal for overlap anastomosis; (3) The esophagus side was prepared intraperitoneal for overlap anastomosis; (4) The overlap esophagojejunostomy was performed; (5) The common outlet was closed after confirmation of anastomosis integrity without bleeding; (6) A thoracic drainage tube was inserted into the thoracic hole with the diaphragm incision closed. The intraoperative and postoperative results were reviewed. Results: All 27 patients were successfully operated, without mortality or conversion to laparotomy. The operative time, digestive tract reconstruction time and esophageal-jejunal anastomosis time were (327.5±102.0) minute, 50 (28-62) minute and (29.0±7.4) minute, respectively. The blood loss was 100 (20-150) ml. The postoperative time to flatus and postoperative hospital stay were (4.7±3.7) days and 9(6-73) days, respectively. Three patients (11.1%) developed postoperative grade III complications according to the Clavien-Dindo classification, including 1 case of anastomotic fistula with empyema, 1 case of pleural effusion and 1 case of pancreatic fistula, all of whom were cured by puncture drainage and anti-infective therapy. Conclusions: The intrathoracic modified overlap esophagojejunostomy is safe and feasible in laparoscopic radical resection of Siewert type II AEG.

[Effect of band ligation or combined with tissue adhesive in the treatment of gastroesophageal varices and portal vein blood flow situational changes].

42 cases with gastroesophageal varices were prospectively included. The groups were treated with endoscopic band ligation or combined with tissue adhesive. The results showed that the left gastric vein internal diameter, average blood flow velocity and blood flow volume after the treatment of band ligation combined with tissue adhesive were significantly lower than that of the treatment of band ligation alone, and the differences were statistically significant (P < 0.05). Spleen and portal vein internal diameter, blood flow and average velocity, the liver and spleen size, shear wave velocity and liver function grade of the two groups after treatment did not change significantly (P > 0.05). The effective rate of band ligation combined with tissue adhesive in the treatment of esophageal and gastric varices (66.67%, 52.38%) were higher than that of band ligation alone (42.85%, 23.81%) (P > 0.05), and the re-bleeding rate of the latter was higher (9.52% and 19.05%, P > 0.05). Hence, it is suggested that the combined therapy is safe and more effective, and has no apparent effect on liver function and portal hypertension.

[Safety and feasibility of laparoscopic double-flap technique in digestive tract reconstruction after proximal gastrectomy for esophagogastric junction tumors larger than 5 cm].

Objective: To investigate the safety and feasibility of laparoscopic double-flap technique (Kamikawa) in digestive tract reconstruction after proximal gastrectomy for esophagogastric junction (EGJ) leiomyoma and gastrointestinal stromal tumor (GIST) with the maximum diameter >5 cm. Methods: A descriptive case-series study was used to retrospectively analyze the data of patients with EGJ leiomyoma and GIST undergoing laparoscopic-assisted proximal gastrectomy and double-flap technique (Kamikawa) at the Department of Gastrointestinal Surgery, Guangdong Hospital of Traditional Chinese Medicine from September 2017 to March 2019. All the tumors invaded the cardia dentate line, and the maximum diameter was >5 cm. After the exclusion of patients requiring emergency surgery and complicating with severe cardiopulmonary diseases, a total of 4 patients, including 3 males and 1 female with age of 29-49 years, were included in this study. After laparoscopic-assisted proximal gastrectomy, the residual stomach was pulled out of the abdominal cavity and marked with methylene blue at the proximal end 3~4 cm from the anterior wall of the residual stomach in the shape of "H". The gastric wall plasma muscular layer was cut along the "H" shape, and the space between the submucosa and the muscular layer was separated to both sides along the longitudinal incision line to make the seromuscular flap. The residual stomach was put back into the abdominal cavity. Under laparoscopy, 4 stitches were intermittently sutured at the upside of "H" shape and 4-5 cm from the posterior wall of the esophageal stump. The stump of the esophagus was cut open, and the submucosa and mucosa were cut under the "H" shape to enter the gastric cavity. The posterior wall of the esophageal stump was sutured continuously with the gastric stump mucosa and submucosa under laparoscopy. The anterior wall of the esophageal stump was sutured continuously with the whole layer of the residual stomach. The anterior wall of the stomach was sutured to cover the esophagus. The anterior gastric muscle flap was sutured and embedded in the esophagus to complete the reconstruction of digestive tract. The morbidity of intraoperative complications and postoperative reflux esophagitis and anastomosis-related complications were observed. Results: All the 4 patients completed the operation successfully, and there was no conversion to laparotomy. The median operative time was 239 (192-261) minutes, the median Kamikawa anastomosis time was 149 (102-163) minutes, and the median intraoperative blood loss was 35 (20-200) ml. The abdominal drainage tube and gastric tube were removed, and the fluid diet was resumed on the first day after surgery in all the 4 patients. The median postoperative hospitalization time was 6 (6-8) days. Postoperative pathology revealed 3 leiomyomas and 1 GIST. There were no postoperative complications such as anastomotic leakage or stenosis, and no reflux symptoms were observed. The median follow-up time was 22 (11-29) months after the operation, and no reflux esophagitis occurred in any of the 4 patients by gastroscopy. Conclusion: For >5 cm EGJ leiomyoma or GIST, double-flap technique (Kamikawa) used for digestive tract reconstruction after proximal gastrectomy is safe and feasible.

[Efficacy of endoscopic approach to reconstruct the medial orbital fracture with perpendicular plate of ethmoid].

Objective:To study the efficacy of endoscopic sinus approach in the repair of medial orbital fracture with perpendicular plate of ethmoid.Method:Retrospective chart was reviewed in 10 cases receiving endoscopic approach to reconstruct the medial orbital fracture with perpendicular plate of ethmoid.We observed the improvement of the symptom such as diplopia, eye movement,and enophthalmos of the preoperative and postoperative.Result:After postoperative follow-up of 4 months to 23 months, all the patients had no graft loss or displacement, infection and other complications, and except for 1 patient with mild diplopia, other patients recovered completely, including eye movement disorder, diplopia,and enophthalmos.Conclusion:Endoscopic approach is a safe and effective treatment in the repair of medial orbital fracture with perpendicular plate of ethmoid.

Dietary supplementation with DHA-rich microalgae improves performance, serum composition, carcass trait, antioxidant status, and fatty acid profile of broilers.

This experiment was conducted with 126 as-hatched male Arbor Acres chicks (1-d-old, weighing 45.3 ± 0.72 g) to determine the effects of microalgae [MA, containing 29% docosahexaenoic acid (DHA)] on performance, serum composition, carcass trait, antioxidant status, and fatty acid deposition of birds. The birds were allocated randomly to 1 of 3 treatments with 7 replicate pens per treatment (6 birds per pen). The dietary treatments included a control diet [corn-soybean basal diet supplemented with 3% soybean oil (SO), CON], 1% MA diet (basal diet supplemented with 1% MA and 2% SO, 1MA), and 2% MA diet (basal diet supplemented with 2% MA and 1% SO, 2MA). All birds were raised in wire-floored cages. The trial consists of a starter phase from d 1 to 21 and a grower phase from d 22 to 42. Compared with CON, birds supplemented with MA (1MA or 2MA) had greater (P < 0.05) average daily gain, liver percentage (liver weight/body weight), and serum glucose, as well as lower (P < 0.05) feed conversation ratio, abdominal fat percentage (abdominal fat weight/body weight), and total serum cholesterol. Moreover, due to the high concentration of DHA in MA, birds fed MA showed increased (P < 0.05) concentration of eicosapentaenoic acid, DHA, superoxide dismutase, and total antioxidant capacity, as well as decreased (P < 0.05) n-6/n-3 polyunsaturated fatty acid ratio, polyunsaturated fatty acid/saturated fatty acid ratio, and malondialdehyde in the breast and thigh muscle compared with CON. In conclusion, dietary supplementation with 1% or 2% DHA-rich microalgae had positive effects on performance, serum composition, carcass trait, antioxidant status, and fatty acid deposition in birds.

A novel near-infrared nanomaterial with high quantum efficiency and its applications in real time in vivo imaging.

Fluorescence imaging signal is severely limited by the quantum efficiency and emission wavelength. To overcome these challenges, novel NIR-emitting K5NdLi2F10 nanoparticles under NIR excitation was introduced as fluorescence imaging probe for the first time. The photostability of K5NdLi2F10 nanoparticles in the water, phosphate buffer saline, fetal bovine serum and living mice was investigated. The fluorescence signal was detected with depths of 3.5 and 2.0 cm in phantom and pork tissue, respectively. Fluorescence spectrum with a significant signal-to-background ratio of 10:1 was captured in living mice. Moreover, clear NIR images were virtualized for the living mice after intravenous injection. The imaging ability of nanoparticles in tumor-beard mice were evaluated, the enrichment of K5NdLi2F10 nanoparticles in tumor site due to the enhanced permeability and retention effect was confirmed. The systematic studies of toxicity, bio-distribution and in-vivo dynamic imaging suggest that these materials give high biocompatibility and low toxicity. These NIR-emitting nanoparticles with high quantum efficiency, high penetration and low toxicity might facilitate tumor identification in deep tissues more sensitively.

DSP-enabled reconfigurable and transparent spectral converters for converging optical and mobile fronthaul/backhaul networks.

Dynamically reconfigurable and transparent signal spectral conversion is expected to play a vital role in seamlessly integrating traditional metropolitan optical networks and mobile fronthaul/backhaul networks. In this paper, a simple digital signal processing (DSP)-enabled spectral converter is proposed and extensively investigated, for the first time, which just utilizes a single standard dual-parallel Mach-Zehnder modulator (DP-MZM) driven by SDN-controllable RF signals and DC bias currents. As an important thrust of the paper, optimum operating conditions of the proposed converter are analytically identified, statistically examined and experimentally verified. Optimum operating condition-supported spectral converter performances in IMDD-based network nodes are explored both theoretically and experimentally in terms of frequency detuning range-dependent conversion efficiency, spectral conversion-induced OSNR/power penalty and transparency to input signal characteristics. The proposed spectral converter has unique advantages including low configuration complexity, strict transparency, SDN-controllable performance reconfigurability and flexibility, as well as negligible spectral conversion-induced latency.

Probiotic supplementation protects weaned pigs against enterotoxigenic Escherichia coli K88 challenge and improves performance similar to antibiotics.

These studies evaluated the effects of probiotics (PB) as a potential substitute for antibiotics (AB) on diarrhea in relation to immune responses and intestinal health in weaned pigs challenged with enterotoxigenic (ETEC) K88 (Exp. 1) and the effects of PB on performance and nutrient digestibility in weaned pigs (Exp. 2). In Exp. 1, 24 weaned barrows (4.9 ± 0.4 kg initial BW) were randomly assigned to 1 of 4 treatments. The treatments consisted of pigs fed an unsupplemented corn-soybean meal basal diet and not challenged (NON-C) or challenged with ETEC K88 (CHA-C) on d 9 and pigs fed the same basal diet supplemented with AB (100 mg/kg zinc bacitracin, 50 mg/kg colistin sulfate, and 100 mg/kg olaquindox; CHA-AB) or 500 mg/kg PB ( and ; CHA-PB) and challenged with ETEC K88 on d 9. In Exp. 2, 108 weaned pigs (7.5 ± 0.9 kg initial BW) not challenged with ETEC K88 were randomly assigned to 1 of 3 treatments, including an AB-free basal diet (CON) and the basal diet with AB (ABD) or 500 mg/kg PB supplementation (PBD). In Exp. 1, after challenge, CHA-C decreased ( < 0.05) ADG and ADFI, whereas CHA-AB and CHA-PB revealed no significant change compared with NON-C. Compared with CHA-C, CHA-AB and CHA-PB improved ( < 0.05) ADG and ADFI and decreased ( < 0.05) the diarrhea incidence in pigs. Mucosal secretory Ig A contents in the jejunum and ileum were greater in CHA-C than in NON-C ( < 0.05) and lower than in CHA-PB ( < 0.05). The diet containing PB alleviated the increase in the endotoxin and diamine oxidase concentration and cecal count ( < 0.05) and the decrease in intestinal villus height, cecal count, and jejunal mucosal occludin protein abundance ( < 0.05). In Exp. 2, dietary supplementation with AB and PB had positive effects on ADG and feed efficiency ( < 0.05). Compared with CON, apparent digestibility of nutrients in PBD was improved ( < 0.05). Collectively, PB supplementation protected the pigs against ETEC K88 infection by enhancing immune responses and attenuating intestinal damage and improved the performance and nutrient digestibility of weaned pigs. Therefore, PB could be a potential effective alternative to AB for ameliorating diarrhea and improving performance in weaned pigs.

Tannin is a key factor in the determination and prediction of energy content in sorghum grains fed to growing pigs.

This study was conducted to determine and compare the DE and ME content as well as the apparent total tract digestibility (ATTD) of GE in 28 samples of sorghum grain fed to growing pigs and to generate prediction equations for DE, ME, and the ATTD of GE based on chemical analysis. The 28 samples included 8 low-tannin sorghum cultivars (LTS; tannin ≤ 0.16%), 10 medium-tannin sorghum cultivars (MTS: 0.67% ≤ tannin ≤ 0.98%), and 10 high-tannin sorghum cultivars (HTS; 1.11% ≤ tannin ≤ 1.51%) obtained from 9 provinces in China and 3 samples of LTS cultivars were obtained internationally. The 28 diets were formulated to contain 96.9% of 1 of the 28 sorghum grains and 3.1% of vitamins and minerals. Eighty-four barrows (36.5 ± 3.4 kg initial BW) were used in a randomized complete block design conducted during 2 consecutive periods ( = 6 per treatment) with the pigs fed different diets during the 2 periods. For each period, pigs were placed in metabolic crates for a 5-d total collection of feces and urine following 7 d of adaptation to the diets. Among the 28 samples, GE, CP, and ADF content (DM basis) ranged from 4,363 to 4,496 kcal/kg, 8.26 to 13.41%, and 3.26 to 5.78%, respectively. The average tannin content was 0.08, 0.84, and 1.29% in the LTS, MTS, and HTS samples, respectively. The DE and ME content (DM basis) ranged from 3,861 to 3,989 and from 3,784 to 3,905 kcal/kg, respectively, in LTS; from 3,646 to 3,740 and from 3,588 to 3,669 kcal/kg, respectively, in MTS; and from 3,481 to 3,617 and from 3,418 to 3,538 kcal/kg, respectively, in HTS. The mean DE, ME, DE/GE, ME/GE, and ATTD of GE in MTS were less than those in LTS ( < 0.05) and greater than those in HTS ( < 0.05). The correlation coefficients between DE, ME, or the ATTD of GE and tannin content were all -0.96 ( < 0.01). The best-fit equations for DE and ME (kcal/kg DM) for the complete set of 28 sorghum grains were 6,974 - (236 × % tannin) - (43.27 × % ADF) + (24.96 × % CP) - (0.71 × % GE) for DE and 3,973 - (262 × % tannin) - (27.24 × % ADF) for ME. Our results strongly indicate that the DE and ME content of sorghum grains are related to their chemical composition, especially their tannin content. The DE and ME content could decrease by more than 200 kcal/kg when the tannin content is increased by 1% in the sorghum grain. Overall, tannin is a key predictor for the DE and ME content as well as the ATTD of GE in sorghum grains, and the potent antinutritive properties from tannin should not be ignored when sorghum is used as an energy source for pigs.

Effects of Coated Compound Proteases on Apparent Total Tract Digestibility of Nutrients and Apparent Ileal Digestibility of Amino Acids for Pigs.

Two experiments were conducted to evaluate effects of coated compound proteases (CC protease) on apparent total tract digestibility (ATTD) of nitrogen (N) and energy, and apparent ileal digestibility (AID) of amino acids (AA) and nutrients in diets for pigs. In Exp. 1, 12 crossbred barrows (initial body weight: 20.14±1.71 kg) were housed in individual metabolism crates and allotted into 2 treatments with 6 piglets per treatment according to weight in a randomized complete block design. The 2 diets were corn-soybean meal basal diets with (0.2 g/kg) or without CC protease supplementation. The CC protease supplementation increased (p<0.05) the digestible and metabolizable N and energy values and the digestibility and retention rate of N in the diet. The ATTD of energy and nutrients had been improved (p<0.05) in the diet supplemented with CC protease. In Exp. 2, 12 crossbred barrows (initial body weight: 20.79±1.94 kg), fitted with T-cannulas at the distal ileum, were blocked by body weight into 2 groups with 6 pigs each. The diets were the same as those in Exp. 1. The CC protease increased (p<0.05) the AID of crude protein and some essential AA including arginine, isoleucine and leucine. The AID and ATTD of energy and nutrients had been improved (p<0.05) by supplemental CC protease, but the hindgut digestibility of nutrients was unaffected. Overall, the CC protease improved the ATTD of N and energy and AID of some indispensible AA and nutrients in the corn-soybean meal diet for pigs. Therefore, the CC protease supplement could improve the utilization of protein in the corn-soybean meal diet and thus contribute to lower N excretion to the environment.

Cause and pre-alarm control of bulking and foaming by Microthrix parvicella--a case study in triple oxidation ditch at a wastewater treatment plant.

The cause and control of foaming and bulking in triple oxidation ditch at a wastewater treatment plant (WWTP) were investigated. The results showed that the foaming and bulking was mainly caused by the excessive propagation of Microthrix parvicella, and mostly occurred in the cold winter and spring. Batch and continuous flow experiments indicated that biological techniques such as reducing sludge retention time (SRT) and increasing F/M ratio, chemical methods such as addition of chlorine (NaOCl), quaternary ammonium salt (QAS), or cationic polyacrylamide flocculants (PAM), polyaluminum salt (PAC) could decrease Sludge Volume Index (SVI) and control foaming and bulking at different levels. In practical application, the shorter SRT was effective to control foaming and bulking in initial stage, although it took longer time. Addition of 10gClkgMLSSd(-1) could gradually change the activated sludge with serious foaming and bulking to normal state within a week. Pre-alert control strategies should be established for the control of filamentous foaming and bulking.

[Experimental study of bone repair induced by cryopreserved allograft periosteum and fetal bone composition in bone defect].

OBJECTIVE: To investigate the repairing effect of transplantation of allogeneic fetal bone in combination with a covering cryopreserved periosteal allograft to bone defect. METHODS: Twenty Long-eared white male rabbits were chosen as experimental model of bilateral 12 mm combined bony and periosteal radial defect. Cryopreserved allograft periosteum with allogeneic fetal bone were implanted in the left defect as experimental side and fetal bone was simply transplanted in the right defect as control side. Bone repair process in the two groups were compared by macroscopy, microscopy, roentgenograms and the contents of calcium and phosphate in the defect area at 2, 4, 8 and 12 weeks after transplantation. RESULTS: There was significant statistic difference in the contents of calcium and phosphate between the experimental and control sides at 4, 8 and 12 weeks after transplantation (P < 0.05). With time passing by, the contents of calcium and phosphate have the increasing trends. In the experimental group, lamella bone was seen and medullary canal recanalized at 8 weeks postoperatively. The histological section showed the bone lacuna and lamella bone were formed. CONCLUSION: It suggests that allogeneic fetal bone in combination with a covering cryopreserved periosteal allograft can promote bone repair, and allogeneic fetal bone is excellent bone substitute.

Myelinating Schwann cells determine the internodal localization of Kv1.1, Kv1.2, Kvbeta2, and Caspr.

We examined the localization of Caspr and the K(+) channels Kv1.1 and Kv1.2, all of which are intrinsic membrane proteins of myelinated axons in the PNS. Caspr is localized to the paranode; Kv1. 1, Kv1.2 and their beta2 subunit are localized to the juxtaparanode. Throughout the internodal region, a strand of Caspr staining is flanked by a double strand of Kv1.1/Kv1.2/Kvbeta2 staining. This tripartite strand apposes the inner mesaxon of the myelin sheath, and forms a circumferential ring that apposes the innermost aspect of Schmidt-Lanterman incisures. The localization of Caspr and Kv1.2 are not disrupted in mice with null mutations of the myelin associated glycoprotein, connexin32, or Kv1.1 genes. At all of these locations, Caspr and Kv1.1/Kv1.2/Kvbeta2 define distinct but interrelated domains of the axonal membrane that appear to be organized by the myelin sheath.

Accumulation of F-spondin in injured peripheral nerve promotes the outgrowth of sensory axons.

F-spondin, an extracellular matrix protein, is present in peripheral nerve during embryonic development, but its amount diminishes by birth. Axotomy of adult rat sciatic nerve, however, causes a massive upregulation of both F-spondin mRNA and protein distal to the lesion. F-spondin in the distal stump of axotomized nerve promotes neurite outgrowth of sensory neurons, as revealed by protein neutralization with F-spondin-specific antibodies. Thus, F-spondin is likely to play a role in promoting axonal regeneration after nerve injury.

Connexin32-null mice develop demyelinating peripheral neuropathy.

Mutations in the gene encoding the gap junction protein connexin32 (Cx32) cause X-linked Charcot-Marie-Tooth disease (CMTX), a common form of inherited demyelinating peripheral neuropathy. To learn more about the pathogenesis of CMTX, we examined the PNS and CNS of cx32-null mice (cx32-/Y males and cx32-/-females) by light and electron microscopy. These mice develop a progressive demyelinating peripheral neuropathy beginning by 3 months of age, and at all ages, motor fibers are more affected than sensory fibers. Like other genes of the X chromosome, the cx32 gene appears to be randomly inactivated, since only some myelinating Schwann cells express Cx32 in heterozygous cx32 +/- females. Heterozygous cx32 +/- females have fewer demyelinated and remyelinated axons than age-matched homozygous cx32-/- females and cx32-/Y males. Although oligodendrocytes also express Cx32, no abnormalities in CNS myelin were found. These findings indicate that a null cx32 allele in myelinating Schwann cells is sufficient to cause an inherited demyelinating neuropathy, so that Cx32 has an essential role in myelinating Schwann cells both in mice and in humans.

Neuregulin expression in PNS neurons: isoforms and regulation by target interactions.

Neuregulins have several important functions in the development of the peripheral nervous system, acting on both developing Schwann cells and muscle fibers. To determine whether these factors are also important for peripheral nerve regeneration, we have analyzed neuregulin expression in motor and sensory neurons by Northern blots and in situ hybridization. The results of this analysis show that the predominant neuregulin isoform expressed in these neurons is a novel transmembrane splice variant. After axotomy, there is a rapid decline in neuregulin expression in both motor and sensory neurons, but following reinnervation of target tissues, neuregulin expression returns to near normal levels. These results indicate that the normal expression of neuregulins in these neurons is maintained by the interactions with target tissues.