[Experimental study of using chitosan nerve conduit combined with PRP to repair facial nerve defect]

Objective:The purpose of this study was to produce chitosan nerve conduit in order to investigate the feasibility of chitosan nerve conduit combined with autologous platelet-rich plasma (PRP) for repairing facial nerve defects.Method:Forty New Zealand white rabbits were randomly divided into four groups (n=10 in each group).Establishment of the facial nerve defect model of the upper buccal branches was placed in the nerve regeneration catheter and injected with the same amount of PRP and saline. The PRP was injected into the chitosan nerve conduit as group A. The physiological saline was injected into the chitosan nerve conduit as group B. The physiological saline was injected into the silicone tube as group C. The PRP was injected into the silicone tube as group D. Eight weeks later,facial nerve gross observation,facial nerve electrophysiological tests,histological observation,image analysis,valuation of nerve regeneration recovery were detected.Result:Five patients were lost to follow up (all five in the modified Semont group),and three patients failed to complete treatment (all three in the Epley group). The sequelae at the 3rd day and one week after modified Semont maneuver were 27 and 9,while 41 and 15 in Epley group. The efficacy rates at the 3rd day and one week after modified Semont maneuver were 91.7% and 98.3%,and 91.9% and 96.8% in Epley group retrospectively. The sequelae and short-term effective rate of patients in modified Semont group was no difference when compared with that in Epley group (P>0.05).Conclusion:The chitosan nerve conduit combined with PRP has a certain effect on the repair of facial nerve defects and is expected to be applied to the repair of clinical facial nerve defects.

[Retrospective study of partial superficial parotidectomy and superficial parotidectomy on superficial parotid benign tumor]

Objective:To compare the clinical effect between partial superficial parotidectomy (PSP) and superficial parotidectomy (SP) through a retrospective analysis and to provide evidence for the benign tumor surgical strategy. Method:According to different surgical strategies performed, 168 patients with superficial parotid benign tumor were reviewed and divided into PSP group and SP group. Clinical data was compared between two groups from different aspects, including operation condition, complications, recurrence rate, as well as parotid function. SPSS 22.0 software was used in statistical analysis. Result:PSP group has an average operative incision length of (6.65±1.17)cm, and average operation time of (82.25±11.56)min, while SP group is (10.86±1.65)cm and (121.42±17.32)min. So, compared with the SP group, PSP has obvious advantages in operation conditions (P<0.01). Furthermore, PSP group also presents an advantage over SP group in occurrence of postoperative complications (P<0.05), while there is no significant difference between two groups in palindromia rate (P>0.05). As for the maintenance of parotid gland functions, PSP group could retain most of parotid functions, but no function would be retained in SP group. Statistical analysis confirms the significance (P<0.05). Conclusion: Compared with SP, in PSP there is declined complication incidence but no increased palindromia recurrence. However, PSP has an apparent advantage on decreased surgical incision length, downscaled operation scope, reduced operation time and retained original functions of gland. All these advantages present the reliability and feasibility of PSP in treating superficial parotid benign tumor.

Accurate wavelength calibration method for compact CCD spectrometer

Wavelength calibration is an important step in charge-coupled device (CCD) spectrometers. In this paper, an accurate calibration method is proposed. A model of a line profile spectrum is built at the beginning, followed by noise reduction, bandwidth correction, and automatic peak-seeking treatment. Experimental tests are conducted on the USB4000 spectrometer with a mercury-argon calibration light source. Compared with the traditional method, the results show that this wavelength calibration procedure obtains higher accuracy and the deviations are within 0.1 nm.

[Current status and further prospects of dental resin-based materials with antibacterial properties]

The mode of dental antibacterial resin-based materials can be divided into two types, namely, single and combined antibacterial mode. With regard to single antibacterial mode, only one kind of antibacterial agent is added into the resin, which can be released or act as contacting antibacterial agent. The single mode resin has limitation in sterilization methods and effect. As for combined antibacterial mode, it is a combination of different types of biocides and thus maximizes the sterilizing effect, including the releasing antibacterial agent incorporated with the contacting antibacterial agent or antibacterial agents combined with calcium compound possessing biological mineralization function. In this paper, current status and further prospects of dental resin-based materials with antibacterial properties are reviewed from the perspectives of single and combined antibacterial modes to provide guidance for dental antibacterial resin material research.

Cloning and sequence analysis of sucrose phosphate synthase gene from varieties of Pennisetum species

Sucrose phosphate synthase (SPS) is an enzyme used by higher plants for sucrose synthesis. In this study, three primer sets were designed on the basis of known SPS sequences from maize (GenBank: NM_001112224.1) and sugarcane (GenBank: JN584485.1), and five novel SPS genes were identified by RT-PCR from the genomes of Pennisetum spp (the hybrid P. americanum x P. purpureum, P. purpureum Schum., P. purpureum Schum. cv. Red, P. purpureum Schum. cv. Taiwan, and P. purpureum Schum. cv. Mott). The cloned sequences showed 99.9% identity and 80-88% similarity to the SPS sequences of other plants. The SPS gene of hybrid Pennisetum had one nucleotide and four amino acid polymorphisms compared to the other four germplasms, and cluster analysis was performed to assess genetic diversity in this species. Additional characterization of the SPS gene product can potentially allow Pennisetum to be exploited as a biofuel source.

Label-free, real-time detection of the dynamic processes of protein degradation using oblique-incidence reflectivity difference method

Based on the requirements for studying the dynamic process of proteinase action substrates in life science, we selected six random proteins including 1L-10, SCGB2A2, CENPQ, GST, HK1, KLHL7, as well as five different concentrations of 1L-10 proteins of 1 mg/ml, 0.5 mg/ml, 0.25 mg/ml, 0.125 mg/ml, and 0.0625 mg/ml, and fabricated two types of substrate protein microarrays, respectively. We detected the dynamic processes of proteins degraded by proteinase K using oblique-incidence reflectivity difference (OIRD) method in a label-free and real-time manner. We obtained the relevant degradation velocities and the degradation time. The experimental results demonstrate that OIRD has the ability to study proteinase action substrates which is out of reach of label methods and is expected to offer opportunities to determine protease-substrate relationships on the systems biology level.

Histological changes within dental pulps in teeth with moderate-to-severe chronic periodontitis

AIM

To investigate the effect of chronic periodontitis on dental pulps by assessing histological changes in the pulps of teeth with moderate-to-severe periodontitis.

METHODOLOGY

A total of 242 teeth from 162 patients with moderate-to-severe periodontitis were collected, and histological changes in pulps were investigated by staining with haematoxylin and eosin. Baseline data were taken from the patients' records before extraction. The morphologic changes observed in the pulp were classified as degree I, degree II, degree III and degree IV. Statistical analysis of the severity of periodontitis and histological changes with the pulps was applied using the Mann-Whitney U rank sum test, whilst the contingency coefficient was used to analyse the inter-relationship between the severity of periodontitis and histological changes in the pulps.

RESULTS

The inter-relationship between the severity of periodontitis and histological changes in the pulps was 0.274 (P < 0.001), and significant differences existed between teeth with moderate periodontitis and severe periodontitis group (Z = 4.145, P < 0.001). The inter-relationship between attachment loss and histological changes in the pulps was 0.397 (P < 0.001). There were significant differences in the histological changes amongst teeth with various degrees of attachment loss (χ(2) = 33.023, P < 0.001) and amongst teeth in different locations (χ(2) = 23.163, P < 0.001).

CONCLUSIONS

There was a positive association between the severity of periodontitis and histological changes within the pulp. More attachment loss was correlated with pathological changes within the dental pulp.

In vivo measurement of the subchondral bone thickness of lumbar facet joint using magnetic resonance imaging

OBJECTIVE

To measure in vivo thicknesses of the facet joint subchondral bone across genders, age groups, with or without low back pain symptom groups and spinal levels.

METHODS

Lumbar (L1-L2 to L5-S1) magnetic resonance (MR) imaging was performed in 81 subjects (41 males and 40 females, mean age 37.6 years). Thicknesses of the subchondral bone were measured in 1620 facet joints using the MR images with custom-written image processing algorithms together with a multi-threshold segmentation technique using each facet joint's middle axial-slice. This method was validated with 12 cadaver facet joints, scanned with both MR and micro-computed tomography images.

RESULTS

An overall average thickness value for the 1620 analyzed joints was measured as 1.56±0.01 mm. The subchondral bone thickness values showed significant increases with successive lower spinal levels in the subjects without low back pain. The facet joint subchondral bone thickness in asymptomatic females was much smaller than in asymptomatic males. Mean subchondral bone thickness in the superior facet was greater than that in the inferior facet in both female and male asymptomatic subjects.

CONCLUSIONS

This study is the first to quantitatively show subchondral bone thickness using a validated MR-based technique. The subchondral bone thickness was greater in asymptomatic males and increased with each successive lower spinal level. These findings may suggest that the subchondral bone thickness increases with loading. Furthermore, the superior facet subchondral bone was thicker than the inferior facet in all cases regardless of gender, age or spinal level in the subjects without low back pain. More research is needed to link subchondral bone microstructure to facet joint kinematics and spinal loads.

Experimental Study on Angiogenesis in a Rabbit VX2 Early Liver Tumour by Perfusion Computed Tomography

Ten rabbits implanted with VX2 liver tumours were investigated by perfusion computed tomography (PCT) imaging 1 week (early) and 2 weeks (late) after tumour induction; 10 other rabbits were non-implanted controls. Time–density curves, perfusion parametric maps and perfusion parameters were obtained for tumour rim and normal tissue surrounding the tumour, and for liver tissue from the controls. In addition, microvessel density (MVD) and vascular endothelial growth factor (VEGF) were studied by immunohistochemistry 2 weeks after tumour implantation. A deconvolution mathematical model was used to calculate hepatic blood flow (HBF), hepatic blood volume (HBV), mean transit time (MTT), capillary vessel surface permeability (PS) and hepatic arterial index (HAI). At the tumour rim on the early PCT scan, MTT was significantly lower whereas HBF, HBV, HAI and PS were significantly higher than in surrounding normal tissue. There were no significant changes in perfusion parameters on the late PCT scan compared with the early scan. Significant linear correlations of MVD and VEGF were found with HBF, PS and HAI, but not with HBV or MTT. It is concluded that PCT imaging is useful for the evaluation of tumour angiogenesis and for the early detection of liver tumours.

A novel gas sensor based on field ionization from ZnO nanowires: moderate working voltage and high stability

We report a kind of gas sensor using ZnO nanowires as the field ionization anode. The sharp tips of nanowires generate very high electric fields at relatively low voltages. The sensors show good sensitivity and selectivity. Moreover, the detection limitation of the field ionization based ZnO nanowire gas sensors is about 5%. More importantly, a sensor with ZnO nanowires as the anode exhibits an impressive performance with respect to stability and anti-oxidation behavior, which are significantly better than those of carbon nanotubes (CNTs) as electrodes. Therefore, the simple, low-cost, sensors described here could be deployed for a variety of applications.

Altered osmotic swelling behavior of proteoglycan-depleted bovine articular cartilage using high frequency ultrasound

Swelling behavior is an electrochemical mechanical property of articular cartilage. It plays an important role in weight bearing and joint lubrication. In this study, the altered transient and inhomogeneous swelling behavior of the degenerated articular cartilage was observed and quantified in situ using ultrasound. Three groups of bovine patellar articular cartilage samples (n = 10 x 3) were obtained and digested by trypsin for 10, 20 and 30 min respectively to mimic different levels of degeneration. The osmotic-free shrinkage and swelling behavior induced by changing the concentration of the bathing saline solution from 0.15 M to 2 M and then back to 0.15 M were characterized using high-frequency ultrasound (central frequency = 35 MHz) before and after digestion. It was found that the degenerated cartilage specimens showed a weaker shrinkage-swelling behavior compared with the normal cartilage samples. However, no significant differences in the peak shrinkage or swelling strains were observed between different groups. The absolute values of the peak shrinkage strain significantly (p < 0.05) decreased by 45.4%, 42.1% and 50.6% respectively after the trypsin digestion for 10, 20 and 30 min, but such significance was not demonstrated for the peak swelling strains. Due to the potential alterations in the collagen-PG matrix during trypsin digestion, the correlation between the swelling strain and the shrinkage strain of the degenerated samples changed slightly in comparison with the normal samples. The proposed ultrasound method has been successfully used to measure the transient and inhomogeneous swelling behavior of the degenerated articular cartilage and has the potential for the characterization of osteoarthritis.

Low-temperature synthesis and photocatalytic properties of ZnO nanotubes by thermal oxidation of Zn nanowires

A low-cost and catalyst-free two-step approach has been developed to produce ZnO nanotubes (ZNTs) by simple thermal oxidation of Zn nanowires under 20 Pa at a low temperature of 400 °C. The growth mechanism of ZNTs is discussed in detail. The formation of these tubular structures is closely linked to the oxidation pressure and temperature, which involves a process consisting of the deposition of Zn nanowires, cracking of the Zn nanowires and sublimation of the Zn cores, and subsequent oxidation to ZNTs. The optical properties were studied by using Raman and photoluminescence spectra, where a strong green emission related to the single ionized oxygen vacancy appears. The photocatalytic activity measurement indicates an enhanced photocatalytic activity of the prepared ZNTs due to their high surface-to-volume ratios and abundant oxygen vacancies near the surfaces of the ZNTs. This type of high surface area structural ZNTs could find promising potential for optoelectronic and environmental applications.

Visible-blind, ultraviolet-sensitive photodetector based on SrTiO3 single crystal

High-sensitivity and visible-blind ultraviolet (UV) photoconductive detectors based on SrTiO(3) single crystal with interdigitated electrodes are reported. The responsivities of photovoltage and photocurrent can reach 2.13x10(5) V/W and 213 mA/W, respectively, at 330 nm at ambient temperature, and the corresponding quantum efficiency eta reaches 80.2%. The dark current is lower than 50 pA at 10 V bias, and the UV/visible contrast ratio is about four orders of magnitude with a sharp cutoff at 390 nm. The experimental results demonstrate that SrTiO(3) single crystal has potentially wide applications in UV detection.

Multilineage differentiation of ectomesenchymal cells isolated from the first branchial arch

Cranial neural crest-derived ectomesenchymal cells may be pluripotent stem cells that are capable of generating a range of phenotypes. The fate of these cells appears to be determined in part by intrinsic genetic programs and also by the influence of extracellular signals in the local environment. The extent of lineage determination once neural crest cells have migrated to the first branchial arch is not clear, although branchial arch pattern is not thought to be the result of crest predetermination. The aim of the present study was to test the hypothesis that ectomesenchymal cells of the first branchial arch show properties of pluripotent stem cells, the lineage of which may be directed by specific molecular signaling. Ectomesenchymal cells were enzymatically isolated from the mandibular processes of BALB/c mice and maintained in an undifferentiated state while cultured with leukemia inhibitory factor or induced to differentiate by lineage-specific induction factors or growth conditions, including transforming growth factor beta, forskolin, and a mineralization-promoting medium. Morphological observations and immunocytochemistry demonstrated that cells could be induced to differentiate into smooth muscle cells, glial cells, and osteoblasts, respectively. In the presence of the mineralization-promoting medium, alkaline phosphatase activity increased significantly and mineralization nodules formed. The data reported support the concept that many, although not all, first branchial arch-derived ectomesenchymal cells show properties of multipotent stem cells, the subsequent fate of which can be influenced by induction factors and growth conditions. Some cells, however, showed a degree of commitment with respect to their fate. The possible application of first branchial arch-derived stem cells to tissue engineering of the orofacial tissues should involve consideration of the developmental stage of cell harvesting and the desired cell fate.

Overexpression of iNOS and down-regulation of BMPs-2, 4 and 7 in retinoic acid induced cleft palate formation

The present work studied the induction of cleft palate formation in embryos developed from pregnant BALB/c mice treated orally with retinoic acid (RA). Previous studies on mature somatic cell types showed that RA exerted inhibitory effects on inducible nitric oxide synthase (iNOS) production. For the first time, our study has shown that RA actually stimulates significant expression of iNOS at specific zones of the affected embryonic palatal tissues at three consecutive stages, from gestation day 13 (GD13) to day 16 (GD16). Enzymatically, iNOS facilitates intracellular nitric oxide (NO) synthesis from L-arginine. When NO reacts with reactive superoxides it may result in irreparable cell injury. NO was also reported to induce apoptosis in some mammalian cell systems. Based on our findings, we propose that such an increase in NO production might be associated with apoptosis in the embryonic palatal tissues in the RA-treated mice. The detrimental effects of NO resulted in a reduction in proliferating palatal cells and therefore disturbed the normal plasticity of the palatal shelves. With iNOS overexpression, our findings also showed that there was significant concomitant down-regulation in the expressions of Bone Morphogenetic Proteins (BMPs) -2, 4, and 7 with regional variations particularly in the palatal mesenchymal cells for those embryos developing cleft palate. Since specific spatial and temporal expressions of BMPs -2, 4, and 7 are critical during normal palatal morphogenesis, any deficiency in the epithelial-mesenchymal interaction may result in retarding growth at the embryonic palatal shelves. Taken together, our study has demonstrated cleft palate formation in the BALB/c embryos involved overexpression of iNOS and down-regulation of BMPs-2, 4 and 7.

Transcriptional mRNA of BMP-2, 3, 4 and 5 in trigeminal nerve, benign and malignant peripheral nerve sheath tumors

The aim of our study was to document whether relationships existed among bone morphogenetic proteins (BMPs), peripheral nerve and neoplastic lesions of nerve sheath tumors. The mRNA transcriptions of BMP-2, 3, 4 and 5 in 10 cases of schwannoma, three cases of malignant schwannoma and two cases of trigeminal neuralgia were detected using an in situ hybridization technique. Our results demonstrated that the myelin sheaths of Schwann cell from the peripheral neuroectomy of trigeminal neuralgia positively expressed mRNA of BMP-2, 3, 4, and 5. The most interesting finding was that the nerve fibers of trigeminal nerve showed only BMP-2 positive staining. All of the neoplastic lesions of nerve sheath showed a consistent but variant expression of BMP-2, 3, 4, and 5. The expression signals of BMP-2, 3, 5 mRNA in malignant schwannoma were relatively lower than in benign lesions except for the expression of BMP-4 mRNA. Our results indicated that selected members of BMPs were expressed in the peripheral nerves that might contribute to the health maintenance, proliferation, regeneration and neoplastic transformation of the peripheral nerve system. Furthermore, the effects of BMP-2, 3, 4 and 5 on peripheral nervous system during neoplastic transformation might be widespread, diverse and antagonistic.

Surface characterization of hydroxyapatite and related calcium phosphates by XPS and TOF-SIMS

The surfaces of six biologically interesting calcium phosphate (CaP) phases (hydroxyapatite, dibasic calcium phosphate dihydrate, dibasic calcium phosphate, monobasic calcium phosphate, beta-tribasic calcium phosphate, octacalcium phosphate) have been examined by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The intensity of an O(1s) shake-up satellite correlates with the phosphate oxygen content. Together with the Ca/P and O/Ca XPS peak ratios, this feature helps provide identification of the CaP phase(s) present in the surface of unknown samples and establish their mole fractions, as proven with a bone sample. Contributions from carbonate impurities can be quantified using its C(1s) peak at 279.9 eV and subtracted from the O(1s) line shape to aid identification. Principal component analysis (PCA) has been applied successfully to analyze TOF-SIMS spectra of these six CaP phases. Multivariate analysis can help differentiate these CaP phases using the first two PCs, which are dominated by the relative intensities of only a few key ions: PO3-, O-, Ca+, CaOH+, PO2-, and OH-.

[Severe side effects of the treatment of acute promyelocytic leukemia with all-trans retinoic acid]

Sixty-three cases with acute promyelocytic leukemia (APL) were treated with all-trans retinoic acid (ATRA). The rates of hyperleukocytosis, intracranial hypertension, retinoic acid syndrome were 57.1%, 9.5%, and 3.2% respectively. Mortality of the treatment was 11.1%. Under ATRA treatment, hyperleukocytosis leading to leukostasis was the cause of death in patients with APL. We therefore suggest that the patients with such leukocyte levels (that is, 5.0 x 10(9).L-1 on the 6th day, 10.0 x 10(9).L-1 on the 10th day, 15.0 x 10(9).L-1 on the 15th day) can be used as guidelines for starting chemotherapy(homoharringtonine); before ATRA treatment, while leukocyte counts are > 10 x 10(9).L-1, the patients only receive homoharringtonine; when leukocyte counts are < or = 5.0 x 10(9).L-1, the patients receive a combination of homoharringtonine and ATRA. Retinoic acid syndrome is a distinctive complication of ATRA therapy in the patients with APL. While the syndrome occurs, the treatment of ATRA must be stopped and corticosteroids must be used.

[Effects of rhGM-CSF and rhG-CSF on growth of CFU-F derived from acute leukemia (AL) patient bone marrow in vitro]

By using the cultural method of CFU-F derived from bone marrow in the patient with acute leukemia in vitro, we dissected the effects of rhGM-CSF and rhG-CSF on growth of CFU-F derived from AL patient bone marrow. The results showed that rhGM-CSF and rhG-CSF enhanced the number of colonies of CFU-F and its proliferation activity. Both factors had a synergy on the above effects. The effects of rhGM-CSF on CFU-F were significantly greater than that of rhG-CSF. The data indicate that rhGM-CSF and rhG-CSF might regulate hemopoiesis more effectively by stimulating the growth of fibroblast and improving bone marrow microenvironment.

The requirement of low calcium dialysate in patients on continuous ambulatory peritoneal dialysis receiving calcium carbonate as a phosphate binder

In the present study we investigated the requirement of low calcium dialysate in 35 patients on continuous ambulatory peritoneal dialysis (CAPD) receiving calcium carbonate as the sole phosphate binder over a 12-month period. Patients with corrected serum calcium > or = 2.85 mmol/L after switching to oral calcium carbonate were given 1 to 3 2-litre exchanges of 2.5 mEq/L calcium dialysate. Serum phosphate level dropped from the pretreatment value of 2.95 +/- 0.62 to a level of between 1.70 +/- 0.41 to 2.03 +/- 0.44 mmol/L 2 weeks after therapy. Corrected serum calcium level increased significantly from 2 weeks onwards. Serum alkaline phosphatase rose initially at 2 and 6 weeks and decreased from 3 months onwards. Serum parathyroid hormone level dropped significantly from a mean pretreatment level of 569 to 320 pg/ml after 12 months (p < 0.001). Serum aluminum decreased significantly from a mean of 1.04 to 0.65 umol/L (p < 0.01). Daily calcium carbonate requirement fluctuated but tended to increase till 8 months and plateaued and ranged from 2.61 +/- 0.57 to 3.98 +/- 2.11 gm. The daily requirement of low calcium dialysate followed a similar trend with approximately three-quarters of patients ultimately requiring at least 1 bag of low calcium dialysate. Eight patients did not require low calcium dialysate. Patients who required low calcium dialysate were significantly older, had a significantly lower pretreatment serum parathyroid hormone and higher serum aluminum levels than those who did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of thalassemia on the response to recombinant human erythropoietin in dialysis patients

Thalassemia is a common genetic disorder among the South Chinese. To see if thalassemia would adversely affect the erythrocyte response to recombinant human erythropoietin (rHuEPO, Epogen) in dialysis patients, the response to rHuEPO in 4 dialysis patients with thalassemic traits (thal-t) was compared with that of 4 control patients who were matched for age, sex, mode of dialysis and baseline hemoglobin levels over a 6-month period. Patients with thal-t showed a reduced erythrocyte response to rHuEPO compared to control dialysis patients as reflected by a reduced reticulocyte index, a slower rise in hemoglobin or hematocrit levels, requirement of a higher cumulated dose of rHuEPO to achieve a target hemoglobin of 10 g/dl and a higher maintenance dose of rHuEPO. A dialysis patient with hemoglobin H disease (HbHD) was also studied. He failed to respond to rHuEPO despite that the dose was increased to 250 U/kg/week. In contrast, his matched control dialysis patient, despite a lower baseline hemoglobin level (6.1 versus 8.8 g/dl), was able to reach a target hemoglobin level of 10 g/dl by 6 weeks and could be maintained at this level with 50 U/kg/week. The patient with HbHD had splenomegaly and a higher baseline serum erythropoietin level, reticulocyte count, serum bilirubin, serum ferritin and serum iron saturation than control patients and patients with thal-t. It was concluded that thal-t reduces the erythrocyte response to rHuEPO in dialysis patients and that in the presence of active hemolysis and enhanced endogenous erythropoietin secretion, dialysis patients with HbHD are resistant to treatment with rHuEPO.