Phases and thermoelectric properties of SnTe with (Ge, Mn) co-doping.

A lead-free SnTe compound shows good electrical properties but also high thermal conductivity, resulting in a low figure of merit ZT. We demonstrate a significant enhancement of the thermoelectric properties of SnTe by (Ge, Mn) co-doping. (Ge, Mn) co-doped samples (Sn0.8Ge0.2)1-xMnxTe with x = 0, 0.03, 0.06, 0.09, 0.12, 0.15, 0.18 and 0.2 were prepared for this investigation. The substitution of Ge for Sn in SnTe promotes the solubility of Mn in a SnTe-based phase up to 20 at%, which further enlarges the band gap and gives rise to enhanced valence band convergence as compared with Mn doping, leading to a notably increased Seebeck coefficient and a power factor. All alloys retain p-type conduction and hole carrier concentration increases with increasing Mn content. The solute Ge and Mn atoms as well as the second phase of Ge in a SnTe-based system enhance phonon scattering and thus reduce thermal conductivity. The synergistic role that Ge and Mn play in regulating the electron and phonon transport of SnTe yields a maximum figure of merit ZT of 1.22 at 873 K for the sample (Sn0.8Ge0.2)0.85Mn0.15Te.

[Analysis of cardiac troponin C gene TNNC1 c. G175C mutation in a Chinese pedigree with familial hypertrophic cardiomyopathy and the correlation between genotype and phenotype].

Objective: To investigate the genotype-phenotype correlation in Chinese familial hypertrophic cardiomyopathy (HCM )focusing on the cardiac troponin C gene TNNC1 c. G175C mutation. Methods: All family members of a Chinese pedigree with hypertrophic cardiomyopathy admitted in Third People's Hospital of Qingdao in February 2005 and 200 healthy volunteers were included in this study. The coding exons of 30 hypertrophic cardiomyopathy associated genes were identified by whole exons amplification and high-throughput sequencing in the proband, and the identified mutation were further detected through bi-directional Sanger sequencing in all family members and 200 healthy volunteers. Pedigree analysis included clinical manifestation, physical examination, ECG and echocardiogram. Results: A missense mutation c. G175C was identified in the TNNC1 gene in 2 family members, which resulted in a glutamic acid (E) to glutamine (Q) exchange at amino acid residue 59. A mutation c. A1319G was identified in the MYLK2 gene in 1 family member, which resulted in a lysine (K) to arginine (R) exchange at amino acid residue 440. These mutations were absent in 200 healthy controls. The proband carried the two kinds of mutations and expressed various clinical manifestations of heart failure and had history of ventricular tachycardia, paraxial atrial fibrillation, pacemaker implantation, electrocardiogram showed right bundle branch block and echocardiography examination evidenced thickened interventricular septum (23.3 mm) and apex and reduced wall motion of these segments. The daughter of the proband carried the TNNC1 c. G175C mutation and was also diagnosed with asymptomatic HCM by echocardiography with thickened interventricular septum (19 mm) and apex (15 mm). Conclusion: The novel missense mutation of TNNC1 c. G175C might be the disease-causing gene mutation in this Chinese pedigree with familiar HCM.

Agricultural intensification leads to higher nitrate levels in Lake Ontario tributaries.

Eutrophication remains the most widespread water quality impairment globally and is commonly associated with excess nitrogen (N) and phosphorus (P) inputs to surface waters from agricultural runoff. In southern Ontario, Canada, increases in nitrate (NO3-N) concentrations as well as declines in total phosphorus (TP) concentration have been observed over the past four decades at predominantly agricultural watersheds, where major expansions in row crop production at the expense of pasture and forage have occurred. This study used a space-for-time approach to test whether 'agricultural intensification', herein defined as increases in row crop area (primarily corn-soybean-winter wheat rotation) at the expense of mixed livestock and forage/pasture, could explain increases in NO3-N and declines in TP over time. We found a clear, positive relationship between the extent of row crop area within watersheds and NO3-N losses, such that tributary NO3-N concentrations and export were predicted to increase by ~0.4 mg/L and ~130 kg/km2 respectively, for every 10% expansion in row crop area. There was also a significant positive relationship between row crop area and total dissolved phosphorus (TDP) concentration, but not export, and TP was not correlated with any form of landcover. Instead, TP was strongly associated with storm events, and was more sensitive to hydrologic condition than to landcover. These results suggest that pervasive shifts toward tile-drained corn and soybean production could explain increases in tributary NO3-N levels in this region. The relationship between changes in agriculture and P is less clear, but the significant association between dissolved P and row crop area suggests that increased adoption of reduced tillage practices and tile drainage may enhance subsurface losses of P.

Comb-shaped conjugates comprising hydroxypropyl cellulose backbones and low-molecular-weight poly(N-isopropylacryamide) side chains for smart hydrogels: synthesis, characterization, and biomedical applications.

Hydroxypropyl cellulose (HPC) possesses a lower critical solution temperature (LCST) above 40 °C, while the poly(N-isopropylacrylamide) (P(NIPAAm)) exhibits a LCST of about 32 °C. Herein, comb-shaped copolymer conjugates of HPC backbones and low-molecular-weight P(NIPAAm) side chains (HPC-g-P(NIPAAm) or HPN) were prepared via atom transfer radical polymerization (ATRP) from the bromoisobutyryl-functionalized HPC biopolymers. By changing the composition ratio of HPC and P(NIPAAm), the LCSTs of HPNs can be adjusted to be lower than the body temperature. The MTT assay from the HEK293 cell line indicated that HPNs possess reduced cytotoxicity. Some of the hydroxyl groups of HPNs were used as cross-linking sites for the preparation of stable HPN hydrogels. In comparison with the HPC hydrogels, the cross-linked HPN hydrogels possess interconnected pore structures and higher swelling ratios. The in vitro release kinetics of fluorescein isothiocyanate-labeled dextran and BSA (or dextran-FITC and BSA-FITC) as model drugs from the hydrogels showed that the HPN hydrogels are suitable for long-term sustained release of macromolecular drugs at body temperature.

Well-defined poly(2-hydroxyl-3-(2-hydroxyethylamino)propyl methacrylate) vectors with low toxicity and high gene transfection efficiency.

Successful gene delivery vectors for clinical translation should have high transfection efficiency and minimal toxicity. In this work, well-defined poly(2-hydroxyl-3-(2-hydroxyethylamino)propyl methacrylate) (PGEA) vectors with flanking cationic secondary amine and nonionic hydroxyl units were prepared via the ring-opening reaction of the pendant epoxide groups of poly(glycidyl methacrylate) with the amine moieties of ethanolamine. It was found that PGEA carriers possess very low toxicity (<10% of the toxicity of branched polyethylenimine (PEI, 25 kDa), while exhibiting surprisingly excellent transfection efficiency (higher than or comparable to that of PEI (25 kDa)) in different cell lines. A series of transfection and cytotoxicity assays revealed that PGEAs are highly promising as a new class of safe and efficient gene delivery vectors for future clinical gene therapies.

Allelotype of endometrial carcinoma.

An allelotype analysis of endometrial carcinoma was undertaken to identify chromosomal loci that are relevant to this tumor type. A total of 70 highly polymorphic microsatellite markers, distributed among all nonacrocentric chromosome arms, were examined for evidence of loss of heterozygosity or allelic imbalance in DNA samples from matched normal and tumor tissues. An average of 21 informative tumor cases were obtained for each marker. Allelic deletions or imbalance were observed on 31 of 41 chromosome arms with no marker showing an allelic loss ratio of greater than 33%. Those chromosome arms most frequently involved were 3p, 8p, 9p, 14q, 16q and 18q. There was a strong correlation between loss of heterozygosity on chromosome 14q and death from disease. These data indicate that the molecular genetic character of endometrial carcinoma is complex and that a relatively large number of different chromosomal loci are likely to play a role in the etiology and progression of this tumor type.

Non-extracorporeal circulation for coronary artery bypass graft surgery is more beneficial than extracorporeal circulation.

OBJECTIVE: The objective of this study was to compare coronary artery bypass graft (CABG) surgery with non-extracorporeal vs. extracorporeal circulation. The study outcomes included operative time, number of graft vessels, pulmonary infection rates, and systemic inflammatory markers. PATIENTS AND METHODS: 96 patients received selective CABG, either with non-extracorporeal (study group; n = 48) or extracorporeal circulation (control group; n = 48). Operative time, pulmonary infection rates, and blood levels of inflammatory markers TNF-α, IL-6, and IL-8 before and 4, 24, and 48 hours after the surgery were quantified. Graft vessels were quantified using computed tomography. RESULTS: Operative time was significantly shorter in study group (4.58 ± 0.91 vs. 5.36 ± 1.12 hours in control group; p < 0.05). The number of graft vessels and pulmonary infection rates were comparable between both techniques. However, systemic inflammatory markers were significantly (p < 0.05) lower in study group at 4 and, partly, 24 hours after the surgery. CONCLUSIONS: Extracorporeal circulation prolongs operation and can aggravate systemic inflammatory response. Therefore, CABG with non-extracorporeal circulation offers more beneficial outcomes.

Studies of esophageal balloon cytology in Linxian, China.

Esophageal cancer is the second leading cause of cancer death in China. Esophageal cancer has a very poor prognosis, principally because most tumors are asymptomatic until they are unresectable. Esophageal balloon cytology is an early detection method developed by Chinese scientists to identify resectable early cancers and precursor lesions. Previous studies have reported high sensitivities for detecting esophageal cancer in symptomatic patients. The current report describes several studies evaluating this diagnostic technique in asymptomatic individuals. A comparison of Chinese and U. S. cytological diagnoses of the same esophageal samples showed that the Chinese categories of precancerous neoplasia were more inclusive than the corresponding U. S. categories. Comparisons of both Chinese and U. S. cytological diagnoses with concurrent histological findings showed low (14-36%) sensitivities for the cytological detection of biopsy-proven cancers. Prospective follow-up studies of several screened cohorts showed a consistent progression of risk for developing esophageal cancer with increasing severity of initial cytological diagnosis. These preliminary studies suggest that esophageal balloon cytology is a useful technique that can benefit from additional research to improve its optimal performance.

Effects of vitamin/mineral supplementation on the proliferation of esophageal squamous epithelium in Linxian, China.

Abnormalities of epithelial proliferation have been proposed as an early step in gastrointestinal carcinogenesis. To determine whether micronutrient supplementation may reduce squamous epithelial proliferation in the esophagus, we evaluated proliferation in subjects participating in a randomized nutrition intervention trial in Linxian, China, where esophageal cancer rates are among the highest in the world. After 30 months of intervention involving daily supplementation with multiple vitamins and minerals, an endoscopic survey was performed and squamous biopsies from 512 subjects were labeled with tritiated thymidine and autoradiographed. Analysis showed no treatment effect on the overall amount of squamous epithelial proliferation measured by the total labeling index. However, a measure of the vertical distribution of labeled cells showed lower values with supplementation: a 14% reduction in all subjects (P = 0.29), and a 29% reduction in nonsmokers (P = 0.03). These results suggest a potential modest benefit for short-term intervention with multiple vitamins and minerals on squamous epithelial cell proliferation of the esophagus in this high-risk population.

Effects of vitamin/mineral supplementation on the prevalence of histological dysplasia and early cancer of the esophagus and stomach: results from the General Population Trial in Linxian, China.

A randomized nutrition intervention trial was conducted among 29,584 adult residents of Linxian, China, to examine the effects of vitamin/mineral supplementation on the occurrence of esophageal/gastric cardia cancer in this high-risk population. A fractional factorial study design allowed evaluations of four different combinations of nutrients: (A) retinol and zinc; (B) riboflavin and niacin; (C) vitamin C and molybdenum; and (D) beta-carotene, vitamin E, and selenium. During the 5.25-year intervention, significant reductions in total mortality, total cancer mortality, and stomach cancer mortality occurred among those receiving beta-carotene, vitamin E, and selenium. At the end of intervention, an endoscopic survey was carried out in a sample of subjects to see if the nutritional supplements had affected the prevalence of clinically silent precancerous lesions and early invasive cancers of the esophagus or stomach. Endoscopy was performed on 391 individuals from two study villages. The prevalences of esophageal and gastric dysplasia and cancer were compared by nutrient factor. Cancer or dysplasia was diagnosed in 15% of the participants. No statistically significant reductions in the prevalence of esophageal or gastric dysplasia or cancer were seen for any of the four vitamin/mineral combinations. The greatest reduction in risk (odds ratio, 0.38; P = 0.09) was seen for the effect of retinol and zinc on the prevalence of gastric cancer. Although no significant protective effects were seen in this endoscopic survey, there was a suggestion that supplementation with retinol and zinc may protect against the development of gastric neoplasia in this high-risk population. Additional studies with larger numbers of endpoints will be needed to further evaluate this possibility.

Effects of vitamin/mineral supplementation on the prevalence of histological dysplasia and early cancer of the esophagus and stomach: results from the Dysplasia Trial in Linxian, China.

Linxian, China has some of the highest rates of esophageal/gastric cardia cancer in the world, and epidemiological evidence suggests that chronically low intake of micronutrients may contribute to these high cancer rates. To examine whether supplementation with multiple vitamins and minerals can affect the occurrence of esophageal/gastric cardia cancer in this population, a two-arm randomized nutrition intervention trial was conducted among 3318 Linxian residents with cytological evidence of esophageal dysplasia. During the 6-year intervention, esophageal/gastric cardia cancer mortality was 8% lower among those receiving the active supplements. After 30 and 72 months of intervention, endoscopic surveys were carried out to see if the nutritional supplements had affected the prevalence of clinically silent precancerous lesions and early invasive cancers of the esophagus and stomach. In the first survey, in 1987, 833 subjects were endoscoped; in the second survey, in 1991, 396 subjects were examined. The histological diagnoses from each survey were compared by treatment group. Cancer or dysplasia was diagnosed in 28% of the subjects endoscoped in 1987 and 24% of those examined in 1991. The odds ratio for subjects in the treatment group (versus those in the placebo group) having esophageal or gastric dysplasia or cancer was 0.84 (95% confidence interval, 0.61-1.15) in 1987 and 0.86 (0.54-1.38) in 1991. Although modest protective effects on worst overall diagnosis were seen in the supplemented group in both surveys, none of the results was statistically significant, and the findings must be considered inconclusive.(ABSTRACT TRUNCATED AT 250 WORDS)

Histological classification of intraepithelial neoplasias and microinvasive squamous carcinoma of the esophagus.

We reviewed a total of 119 resected esophagi with intraepithelial neoplasias of low grade (including slight or moderate dysplasias), high grade (including severe dysplasia and carcinoma in situ), or microinvasive squamous carcinoma (i.e., not invasive beyond the submucosa and without metastases in regional lymph nodes). Epithelial buds bulging into the stroma were noted in noninvasive intraepithelial lesions. The most severe degree of histological alteration was used to characterize each case. Of the 119 cases, five were low-grade, 38 were high-grade, and the remaining 76 specimens contained microinvasive squamous carcinoma. Of these, 23 invaded only the lamina propria. Nine invaded the muscularis mucosae, 16 invaded the inner half of the submucosa, and the remaining 28 invaded the outer half of the submucosa. Epithelial buds were divided according to their configuration into types I, II, and III. Grade I was characterized by regular epithelial buds of the same size, grade II had regular buds that varied in size, and grade III had irregular buds (i.e., buds of varying length and width with irregular contours). Our study of 66 specimens with microinvasive squamous carcinoma showed that one of the two specimens that had low grade dysplasia also had type III buds, while 56 of the remaining 64 (87.7%) with high grade dysplasia also had type III buds. Microinvasion originated at the tip of the type III epithelial buds in 12 specimens. Similar results have been demonstrated in experimental animals. We conclude that in the esophageal mucosa, there is a close relationship among the degree of squamous cellular atypia, the formation of epithelial buds, and the progression toward invasive carcinoma.

A subset of acute nonlymphocytic leukemia with expression of surface antigen CD7--morphologic, cytochemical, immunocytochemical and T cell receptor gene analysis on 13 patients.

An increasing number of acute leukemias coexpressed markers normally believed to be restricted to a single lineage have been found recently. This special subgroup of leukemias have drawn a lot of attention because of their biologic and clinical significance. In a study of 100 consecutive de novo ANLL patients diagnosed by FAB criteria, T-cell antigen CD7 was identified on the leukemic blasts of 13 patients, ten of whom had M1 subtype of leukemia, myeloblastic leukemia without maturation. All the patients showed positive staining with myeloperoxidase and expressed myeloid markers CD13 and/or CD33, but lacked CD11b, a marker of more mature myeloid cells. Combined staining with myeloperoxidase and CD7 of the cells from four patients revealed coexpression of both markers on the same cells. None of the patients expressed the two other T-cell antigens CD2 or CD5. All ten patients who had DNA analysis showed germline configuration of TCR beta and gamma chain genes. One patient had chromosomal translocation involving 11q23, t(11; 19) (q23; p13), which is the site frequently associated with both myeloid and lymphoid malignancies. The clinical implications of this subgroup of patients need further study on more patients, and need longer follow-up.

Mutation and overexpression of the p53 tumor suppressor gene frequently occurs in uterine and ovarian sarcomas.

OBJECTIVE: To determine the frequency of mutation and overexpression of the p53 tumor suppressor gene in female genital tract sarcomas. METHODS: Immunostaining for p53 was performed in frozen sections of 46 ovarian and uterine sarcomas. Single-stranded conformation polymorphism analysis of exons 4-9 of the p53 gene was performed in 33 sarcomas. We performed DNA sequencing of the p53 gene in 22 cases in which we found p53 protein overexpression and/or shifted bands on single-stranded conformation polymorphism analysis. RESULTS: Overexpression of p53 was seen in 27 of 46 sarcomas (59%), including 26 of 41 (63%) mixed mesodermal tumors, one of four (25%) leiomyosarcomas, and zero of one endometrial stromal sarcoma. Among the 33 sarcomas subjected to molecular analysis, 21 demonstrated mutations in the p53 gene (64%). Eighteen cancers had a single mutation, whereas three cases showed two mutations in the p53 gene. There was one mutation in exon 4, seven mutations in exon 5, three mutations in exon 6, six mutations in exon 7, six mutations in exon 8, and one mutation in exon 9. With the exception of one microdeletion, which predicted a truncated protein product, all of the mutations were missense point mutations. All but one of the point mutations resulted in changes in the predicted amino acid sequence. There were 18 transition mutations (75%), five transversions (21%), and one deletion (4%). CONCLUSIONS: Mutation of the p53 tumor suppressor gene, with resultant overexpression of p53 protein, frequently occurs in ovarian and uterine sarcomas. Because most of the mutations are transitions, p53 mutations in these cancers likely arise from spontaneous errors in DNA synthesis and repair rather than from exposure to carcinogens.

The histogenesis of the microinvasive basal cell carcinoma of the esophagus.

The spectrum of histological events ranging from basal cell dysplasia to microinvasive basal cell carcinoma was traced in four of 123 resected esophagi from Chinese subjects. Atypical basal cells could be seen in some areas impinging and pushing, and in other areas invading the underlying stroma. The periphery cell layers in some invading clusters retained the characteristics of the basal cells with palisaded arrangement. In non-invading areas, the intermediate and superficial cells had normal cell maturation with normal nuclei, a feature which distinguishes basal cell intraepithelial dysplasia from squamous cell intraepithelial dysplasia of the esophagus. Similar histological events have been demonstrated in experimental animals fed with an esophagotropic carcinogen.

The induction of esophageal tumors in mice: dose and time dependency.

Three hundred and forty eight C57Bl mice were killed after diethyl-nitrosamine (DEN) treatment at various time intervals ranging from one day to six months. No esophageal tumors occurred in the first three months after DEN treatment; They occurred, however, at four months and increased in number at six months of DEN treatment. Other groups of animals under the same initial DEN treatment were allowed to survive seven or nine months without treatment. One esophageal tumor was recorded at observations made seven months after one single day of DEN administration. A significant increase in the number of esophageal tumors occurred at seven months in mice treated with DEN for two weeks, and for one, two, three or four months; the highest tumor frequency was found in mice treated for six months and surviving three additional months on a carcinogen-free diet. These results suggest that clones of esophageal cells had been "programmed" for tumor growth at an early stage of DEN treatment. The tumors had, however, remained undetected at macroscopical and microscopical examination several months previously. It is apparent that not only the dose administered, but also the post-carcinogen interval is an important factor in esophageal carcinogenesis in the mouse.

Analysis of two sling procedures using polypropylene mesh for treatment of stress urinary incontinence.

OBJECTIVES: To evaluate and compare the surgical outcome between the innovative tension-free vaginal tape (TVT) and conventional pubovaginal sling (PVS) procedures using polypropylene mesh. METHODS: Eighty consecutive women with urodynamic stress urinary incontinence (SUI), who chose to undergo either a TVT (n=23) or a PVS (n=57) procedure using polypropylene mesh based on financial consideration, were recruited for this study. The surgical results were analyzed and compared subjectively and objectively. RESULTS: The mean follow-up interval was 23 months for the TVT and 20 months for the PVS procedure (P=0.062). Postoperatively, SUI (91.3% vs. 93.0%), concomitant urge symptoms (85.0% vs. 85.3%) and the negative impact of incontinence and urogenital distress on patients' quality of life (79.8% vs. 77.8%) (77.4% vs. 68.8%) had improved markedly. After a multivariable logistic regression analysis, the treatment outcome of SUI was found to be independent of the main effects of patient age, parity, concurrent gynecological surgeries, intrinsic sphincter deficiency, previous failed incontinence surgeries, and concomitant urge symptoms. However, it was significantly related to treatment procedures (TVT vs. PVS) and their interaction with patient body mass index (BMI). Based on the fitted logistic model, we see that TVT performs better than PVS when BMI is less than 27.27 kg/m2, and the advantage of TVT decreases as BMI increases. CONCLUSION: Both TVT and PVS procedures using polypropylene mesh are effective treatment modalities for female SUI. However, TVT was not as effective in treating overweight or obese women as PVS.

Surgical management of the hypopharyngeal and cervical esophageal cancer.

Between December 1979 and December 1992, 15 patients with hypopharyngeal and cervical esophageal cancer were treated surgically. Total pharyngolaryngectomy and partial cervical esophagectomy were performed and the defects were reconstructed with cervical skin flaps in 2 cases. The free jejunal segments were used in 6 cases following total pharyngolaryngectomy and cervical esophagectomy, cervical esophagectomy (larynx preserved) was repaired with free jejunal graft in 1 case. The pharyngogastric anastomosis following total pharyngolaryngoesophagectomy were performed in 4 cases, one of them, used pectoralis major myocutaneous flap for resection of soft tissue and skin of the neck. The pectoralis major myocutaneous flap and forearm free flap in 1 case respectively were used to reconstruct the deficits of total laryngectomy and partial pharyngectomy, and partial pharyngolaryngectomy. In our series, 1, 3, 5 years survival rates were 73.3% (11/15), 50% (6/12) and 55.6% (5/9), respectively. The advantages and disadvantages of a variety of operative procedures and the cervical lymph nodes management will be discussed.

[Ultrastructural analysis in differential diagnosis of tumors].

Ultrastructures of 25 tumors were analyzed by electron microscopy (EM). Of the 25 cases, there were 9 amine precursor uptake and decarboxylation tumors (APUD) (2 carotid body tumor, 2 medullary carcinoma of thyroid and 5 carcinoid) in which the dense core granules of different sizes were seen in the cytoplasm. 4 cases of malignant melanoma were identified by EM basing on the premelanosome and melanosome in the cells. In 4 carcinomas from different locations, 2 had mucous secretory granules in the cytoplasm and junction complex between the tumor cells. The diagnosis was finally confirmed as adenocarcinoma. The other 2 cases were identified as epidermoid carcinoma or anaplastic carcinoma as desmosome and tonofilaments were found. 4 cases of malignant lymphoma without any cell junction complex were identified. Moreover, there were several cases of mesenchymal cell tumors, such as leiomyoma, rhabdomyosarcoma, chordoma and Schwannoma confirmed by their special organelles. This study shows that the ultrastructural analysis is valuable in the differential diagnosis and classification of tumors.