Probing hydrogen spillover in Pd@MIL-101(Cr) with a focus on hydrogen chemisorption.

Palladium nanoparticles can split the dihydrogen bond and produce atomic hydrogen. When the metal nanoparticles are in intimate contact with a hydrogen-atom host, chemisorption of H-atoms by the host has been suggested to occur via the hydrogen spillover mechanism. Metal-organic frameworks were predicted to be able to act as effective chemisorption sites, and increased ambient-temperature hydrogen adsorption was reported on several occasions. The intimate contact was supposedly ensured by the use of a carbon bridge. In this work, we show that it is possible to introduce catalyst palladium particles into MOF's pores and simultaneously ensuring good contact, making the employment of the carbon bridge redundant. The addition of Pd nanoparticles indeed increases the ambient-temperature hydrogen uptake of the framework, but this is found to be solely due to palladium hydride formation. In addition, we show that the hydrogen atoms do not chemisorb on the host framework, which excludes the possibility of hydrogen spillover.

Sentinel node biopsy in melanoma delays recurrence but does not change melanoma-related survival: a retrospective analysis of 673 patients.

BACKGROUND: The status of the sentinel lymph node (SLN) is an important parameter to predict the prognosis of melanoma patients but it is a matter of debate if removal of micrometastases by SLN biopsy (SLNB) influences the prognosis of melanoma patients. OBJECTIVES: We sought to investigate the impact of SLNB in melanoma patients with regard to recurrence-free survival, overall survival and metastatic pathways. PATIENTS AND METHODS: We studied, retrospectively, 673 melanoma patients with a primary melanoma (tumour thickness > or = 1 mm) and without clinical evidence of metastases at the time of melanoma diagnosis. In 377 patients the melanoma was removed without SLNB between January 1995 and March 2000 (pre-SLNB group). In 296 patients the melanoma was removed with SLNB between April 2000 and March 2003 (SLNB group). Otherwise, both groups received identical surgical treatment of the primary melanoma and initial staging procedures performed by the same team of physicians. Follow-up recommendations were also identical in both groups. RESULTS: Both groups showed no significant differences with regard to characteristics of the primary melanoma, sex and age. By Kaplan-Meier analyses, melanoma-related overall survival was comparable in both groups. However, recurrence-free survival was increased in pre-SLNB patients due to significantly fewer regional lymph node metastases, whereas frequencies of locoregional cutaneous and distant metastases were comparable in both groups. CONCLUSIONS: SLNB advances the detection of regional lymph node metastases and therefore avoids nodal recurrences but does not influence metastatic behaviour of melanoma cells and does not protect patients from melanoma-related death caused by distant metastases. Thus, our retrospective data favour the marker hypothesis for melanoma metastasation. To elucidate further if subgroups of patients benefit from SLNB, prospective randomized studies with long-term follow-up are needed.

Incidence, impact on survival, and risk factors for multi-organ system failure in children following liver transplantation.

Liver transplantation (LTx) in children currently offers long-term survival rates of more than 80%. Many causes for Tx failure have been identified. However, the incidence and impact of multi-organ system failure (MOSF) are, to date, unknown. Therefore, in this study the role of MOSF after LTx in children was investigated with regard to outcome. The data of 114 children (53 girls, 61 boys; median age 4.3 yr) after first LTx were evaluated retrospectively. The definition of MOSF, as used by Wilkinson et al. [Crit Care Med 1986: 14: 271-274], was modified with regard to age-adjusted values. The influence of MOSF on patient survival was investigated by Kaplan-Meier analysis and multivariate regression analysis. Thirty-one of 114 children with orthotopic LTx developed MOSF (involving two or more organs). In total, 18 children died (15.8%) during the hospitalization; 16 of these had MOSF. Mortality related to two-organ failure was 29.4% (n = 5), to three-organ failure 78% (n = 7), and to four-organ failure 80% (n = 4). The highest mortality rates were observed in children with central nervous system (CNS) and cardiovascular failure, leading to a decreased probability of survival of 0.40 (p < 0.0001). Multi-variate analysis showed that CNS and cardiovascular failure were the most important risk factors for survival (p < 0.0001 and 0.056, respectively). Respiratory and renal failure, in univariate analysis, were significant contributors to poor survival, but had no statistically significant influence on outcome in multivariate analysis. Bone marrow insufficiency was found to have no influence on survival in either analysis. In multivariate analysis, the risk of development of MOSF was significantly increased by high numbers of transfused units of fresh-frozen plasma (FFP), the absence of rejection episodes, or a high bilirubin level prior to Tx. Hence, MOSF is a major factor contributing to the death of children early after LTx. CNS and cardiovascular failure carried the highest risk for a poor outcome. Other risk factors associated with the development of MOSF were: numbers of transfused units of FFP, absence of rejection episodes, and a high pre-Tx bilirubin level.

Compartment-oriented microdissection of regional lymph nodes in medullary thyroid carcinoma.

Lymph node metastases have been proven to be the main prognostic factor in medullary thyroid carcinoma (MTC). This retrospective study was undertaken to evaluate the efficiency of two surgical techniques of regional lymph node dissection with regard to the normalization of pentagastrin-stimulated serum calcitonin level and patient survival: selective lymphadenectomy, i.e., the excision of macroscopically or microscopically involved lymph nodes, versus a systematic lymphadenectomy performed by the new technique of a compartment-oriented microdissection. From 1970 to 1990, 82 patients with sporadic (n = 57) and hereditary (n = 25) MTC underwent a total of 142 operations including 63 selective lymphadenectomies and, since 1986, 35 systematic lymphadenectomies. The study revealed that in node-positive MTC the rate of interventions with a postoperative normalization of pentagastrin-stimulated serum calcitonin was higher after systematic lymphadenectomy (29.2%) than after selective lymphadenectomy (8.5%) (P < 0.01). The rate of patients undergoing repeat surgery due to a recurrence of MTC was 48% after selective lymphadenectomy and 10% after systematic lymphadenectomy. Survival was significantly better for patients after systematic versus selective lymphadenectomy (P < 0.005). This study thus emphasizes that systematic lymphadenectomy, using the technique of a compartment-oriented microdissection of cervicomediastinal lymph nodes, represents the preferred surgical treatment as well as the optimum technique in primary as well as secondary node-positive MTC.

Genetic determinants of airways' colonisation with Pseudomonas aeruginosa in cystic fibrosis.

Exocrine pancreatic insufficiency and lung infection with Pseudomonas aeruginosa are major features of cystic fibrosis (CF). This monogenic disease is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. 267 children and adolescents with CF who were regularly seen at the same centre were assessed for an association of the CFTR mutation genotype with exocrine pancreatic function and the age of onset of chronic colonisation with P aeruginosa. The major mutation delta F508 accounted for 74% of CF alleles; 33 further CFTR mutations had been detected on the CF chromosomes of the study population by June, 1992. With the exception of delta F508/R347P compound heterozygotes, patients of the same mutation genotype were either pancreas insufficient (PI) or pancreas sufficient (PS). The age-specific colonisation rates with P aeruginosa were significantly lower in PS than in PI patients. The missense and splice site mutations that are "mild" CF alleles with respect to exocrine pancreatic function were also "low risk" alleles for the acquisition of P aeruginosa. On the other hand, the proportion of P aeruginosa-positive patients increased most rapidly in the PI delta F508 compound heterozygotes who were carrying a termination mutation in the nucleotide binding fold-encoding exons. Pancreatic status and the risk of chronic airways' colonisation with P aeruginosa are predisposed by the CFTR mutation genotype and can be differentiated by the type and location of the mutations in the CFTR gene.

Lymphadenectomy in gastric carcinoma. A prospective and prognostic study.

In 193 gastric resections for adenocarcinoma, lymphadenectomy was prospectively evaluated to quantify the number of lymph nodes and to identify prognostic factors. Overall, 7112 nodes (median, 36.8 per patient) were resected with 27.2% showing metastases. Most nodes were found in the perigastric region. The histologic type and site of the tumor did not influence the number of invaded nodes, but tumor stage and quality of the resection (curative/palliative) did. By multivariate analysis the tumor stage, curative vs palliative resections, and the number of metastatic lymph nodes in curative resections were independent prognostic factors. Patients with less than six metastatic nodes showed a survival not significantly different from that of patients with normal nodes. These patients may be well treated by surgery alone, but the other patients may require multimodal therapy to improve their prognosis.

New developments in the treatment of gastric carcinoma.

The recent successes being achieved with combination chemotherapy regimens, such as FAMTX (fluorouracil [5-FU], doxorubicin, methotrexate), EAP (etoposide, doxorubicin, cisplatin), and ELF (etoposide, leucovorin, 5-FU), strongly indicate that gastric cancer is chemosensitive. With these regimens, objective remission rates of more than 50% were recorded, including approximately 10% complete remissions (CRs). Moreover, some of these CRs were histopathologically confirmed. The finding that locally advanced disease (LAD) and technically unresectable disease could be rendered resectable by preoperative chemotherapy (EAP) was important. Thirty-six patients with LAD had been treated in a phase II trial with preoperative EAP, inducing 24 (70%) overall remissions (two clinical CRs, six pathologic CRs, 16 partial remissions [PRs] in 35 evaluable patients. Twenty-one patients were disease-free after chemotherapy with or without second-look surgery. The median survival time was 18 months for all patients and 24 months for disease-free patients. At 30+ months, 21% of all patients are still living disease-free. The expected survival of patients with unresectable LAD is approximately 4 to 6 months without any treatment and 6 to 9 months with standard chemotherapy. Compared with the latter results, the preoperative use of effective regimens (eg, EAP) seems to improve prognosis of patients with LAD. Moreover, such a multimodal approach may increase the number of long-term survivors among patients with resectable gastric cancer, especially those whose stage indicates a high risk of relapse (stages IIIa or IIIb). However, partly because of the severe toxicities (myelosuppression, nausea/vomiting), a considerable number of patients cannot be treated with these new regimens for the following reasons: Two of three patients with gastrointestinal disease are older than 60 years. Nontumorous diseases of the cardiovascular system, kidney, and others are frequent in this age group and may complicate or even prevent treatment with aggressive regimens. Considering the predominantly palliative treatment intentions in far advanced (metastasized) gastric cancer, regimens with low toxicities and acceptable activity should be preferred. For these reasons, we developed and investigated the combination ELF in a phase II trial in elderly patients (greater than 65 years) and in patients with cardiac risks who could not be treated with anthracyclines. The overall response rate in 51 evaluable patients was 53% (27 of 51) including six clinical CRs (12%). The median remission duration was 9.5 months and the median survival time was 11 months. Tolerability was excellent. Only 16% and 4% of patients, respectively, experienced WHO grades 3 and 4 leukopenia. Nausea/vomiting and mucositis/stomatitis were mild.(ABSTRACT TRUNCATED AT 400 WORDS)

Miang chewing in northern Thai villagers.

The habit of chewing miang, composed of fermented tea leaves was studied among 100 farmers of Northern Thai origin. It was disclosed that the majority of miang chewers were 'multi-habituees' in that this habit was combined with other oral habits such as betel quid chewing, banana cigar and Thai cigarette smoking and alcohol consumption. Among women the most prevalent habit combination was miang chewing and khi yo cigar smoking whereas men showed a more differentiated habit pattern. A total of 37 men and 21 women showed oral lesions that could be related to the practice of one or several habits. Oral precancerous lesions such as leukoplakia were, however, only found among miang chewers who in addition indulged in other oral habits (betel quid chewing, smoking, alcohol usage).

Postnatal treatment of rats with adrenergic receptor agonists or antagonists influences differentiation of sexual behavior.

The aim of the study was to investigate the possible role of the adrenergic system in development and differentiation of neural centers controlling sexual behavior in adulthood. For this purpose normal and androgenized female rats were treated with the alpha 1-receptor antagonist prazosin, the alpha 2-receptor agonist clonidine, or the alpha 2-receptor antagonist yohimbine-HCl throughout the first week of life. In adulthood all animals were ovariectomized and, after appropriate hormone-priming, they were tested for the capacity to display female and male sexual behavior patterns. Alteration of adrenergic transmission during the critical postnatal period for sexual differentiation of neural centers resulted in significant changes in the capacity to express female lordosis behavior in adulthood. In nonandrogenized animals clonidine significantly reduced the capacity for lordosis behavior. In androgenized animals clonidine had the opposite effect; it attenuated the inhibitory effect of testosterone propionate (TP) on differentiation of lordosis behavior. Prazosin, which was without effect in nonandrogenized animals, also attenuated the inhibitory effect of TP on differentiation of lordosis behavior. Yohimbine was without effect in androgenized and nonandrogenized animals. There was no influence of any of the adrenergic drugs on differentiation of male sexual behavior. In conclusion, differentiation of lordosis behavior seems to be mediated or modulated via adrenergic transmission. The defeminizing effect of testosterone postnatally on the differentiation of lordosis behavior seems to be expressed via alpha 1-adrenergic transmission, and diminished adrenergic activity during the postnatal period seems to protect the developing brain against this effect of testosterone.

Precancerous and other oral mucosal lesions related to chewing, smoking and drinking habits in Thailand.

In a field study (1979-1984) four out of six major hilltribes of Northern Thailand, namely the Lahu, Karen, Lisu and Meo, as well as a group of rural Thai, were examined. Chewing, smoking and drinking habits and lesions of the oral mucosa (leukoedema, preleukoplakia, leukoplakia and chewer's mucosa) were recorded. 1866 individuals were examined. Considerable differences in the chewing and smoking habits among the various tribes were recorded and some of them were considered tribe-specific. Chewing of betel and miang was more prevalent among older people; these habits seem to have lost their attraction for the younger people. Cigarette smoking was more prevalent among middle-aged individuals. Leukoedema was observed in 12.4%, preleukoplakia in 1.8%, leukoplakia in 1.1% and chewer's mucosa in 13.1%. Men and the older generation were affected more often, except that more women (Karen and Thai) revealed chewer's mucosa. A positive correlation could be demonstrated between some mucosal lesions (leukoedema, chewer's mucosa) and some smoking and chewing habits.

[Suitability and comparison of compensating filters for thoracic diagnosis]. / Eignung und Vergleich von Ausgleichsfiltern für die Thoraxdiagnostik.

The effect of three types of filter on the quality of radiographs of the chest was compared. These filters improve visualization of mediastinal structures without significantly reducing the quality of the pulmonary image. In practice the Du Pont filter proved best; the quality of the central and peripheral portions of the lung image is equal to that of an ordinary radiograph and visualization of the mediastinum is improved. The Agfa-Gevaert filter showed no significant disadvantages compared with the ordinary techniques but the improvement in mediastinal visualization is not that marked. The 3 M filter yields poor images of the central portions of the lung and its type of construction prevents the retrocardiac structures from being pictured as well as with the other filters.

Prevalence of dental caries and Streptococcus mutans in Meo of Northern Thailand.

The prevalence of dental caries was studied in 505 Meo, a minority of Northern Thailand, using the DMFT index. Plaque material from all patients was examined qualitatively for S. mutans. The DMFT (dmft) index score ranged between 1.69 and 7.06 with a mean of 2.17 +/- 3.24 for men and 3.45 +/- 3.72 for women. There was a statistical difference in caries prevalence between males and females (P less than 0.05). There was no statistical correlation between miang chewing and caries prevalence. Fluoride concentration of water samples was between 0.043 and 0.077 ppm F-. Of 505 plaque samples, 13.3% were positive for S. mutans, mostly of biotype I. Compared to other Northern Thai hill tribes and the Thai rural population, the Meo appear to have a higher dental caries prevalence rate.

[Comparison of a standard x-ray film with a high-latitude film in thoracic diagnosis]. / Vergleich eines Standard-Röntgen-Films mit einem "high latitude"-Film in der Thoraxdiagnostik.

A comparison of chest radiographs using two films of different gradation (Cronex 4 and Cronex L (R)) shows that the relevant structures are visualized if the technique is optimal, and that the assessment speed is not prolonged. For visualizing the peripheral vessels it seems to be particularly important to employ a technique that provides rich contrasts. However, the less contrasty film makes it definitely easier to visualize the mediastinal structures and the retrocardial vessels. Imaging of the costopleural marginal zone was hardly improved by the L film type, using the technique employed here.

Streptococcus mutans and caries prevalence in rural Thai.

The prevalence of dental caries was studied in 521 rural Thai using the DMFT index. The oral habit of chewing betel nut was recorded. Samples of drinking water were examined for fluoride concentrations. Plaque material from 500 patients was examined qualitatively for S. mutans. The DMFT (dmft) index score was comparably high for patients under 10 yr of age (4.12); the difference between the DMFT (dmft) score of this age group and the other age groups was statistically significant. The average DMFT (dmft) score was 1.34 +/- 2.67. There was no relation between oral habits and caries prevalence. Fluoride concentrations of the water samples were between 0.11 and 1.64 ppmF- X 14.2% of 500 plaque samples were positive for S. mutans, predominantly of biotype I. The higher prevalence of caries in children may be attributable to changing patterns of life and nutrition.

Comparison of histology and immunohistochemistry with thyroglobulin serum levels and radioiodine uptake in recurrences and metastases of differentiated thyroid carcinomas.

The importance of lightmicroscopical and immunohistochemical features of 38 recurrent differentiated thyroid carcinomas (27 papillary carcinomas (PC), 11 follicular carcinomas (FC] for post-operative serum thyroglobulin (TG) concentrations was analysed in regard to pre-operative serum TG levels with tumour type, histological and cytological differentiation, volume fraction of TG synthesizing tumour cells (TG immunohistomorphometry), tumour volume and radioiodine uptake (RIU). Serum TG concentrations increased with tumour size and the number of TG synthesizing tumour cells (r = 0.5). PC and FC did not differ in their volume proportions of TG synthesizing tumour cells, while TG serum levels in FC significantly exceeded those of PC of similar size. The low TG serum levels found in PC might be explained by a specific defect in thyroglobulin secretion. Carcinomas with partial or total cytologic metaplasia (e.g. oxyphilic carcinomas) had low volume proportions of TG synthesizing cells and low serum TG levels. Thirteen of the 38 differentiated carcinomas (34.2%) showed both high TG serum levels and positive RIU, 17 (44.7%) disclosed only elevated TG serum levels and 6 (15.8%) a positive RIU. In two cases (5.3%) TG serum levels were not elevated and RIU's were negative. TG immunostaining was positive in all 38 cases. In summary, TG serum levels depend on the following morphologic factors in differentiated thyroid carcinomas: 1) Number of TG synthesizing tumour cells, 2) Mode of TG secretion and 3) Cytological differentiation of the tumour cells. Serum TG levels did not predict total body iodine scan.

Growth and function of thirty-four human benign and malignant thyroid xenografts in untreated nude mice.

Tissue was taken from 16 patients with benign thyroid lesions (10 nontoxic nodular colloid goiter, two follicular adenoma, one autonomous adenoma, one iodine-induced thyrotoxicosis, 2 Graves' disease) and 18 patients with malignant thyroid tumors [seven papillary, five follicular, five undifferentiated (anaplastic), and one medullalry carcinoma] and was xenotransplanted into the flanks of 124 syngeneic female BALB/c-nu/nu mice 6 weeks of age. Subsequently, without any further treatment, serum levels of thyroglobulin (TG), T3, T4, and thyroid-stimulating hormone were determined by radioimmunoassay at 4 or 5 weeks posttransplantation and at the end of the experimental time period of 4 months. All animals were autopsied. The grafts were examined by light microscopy and TG immunohistochemistry. Morphologically, the grafts of benign and malignant thyroid tumors showed features overall identical to the original tissue. Conversely, nontoxic nodular colloid goiter and Graves' disease grafts revealed a transformation to normofollicular structures. All benign thyroid grafts showed a stationary growth, as did most differentiated thyroid carcinomas. Tumor take rates in differentiated and in medullary carcinoma were 15%, and in undifferentiated carcinomas, 100%. In the cancer grafts, a correlation between resting phase (period until progressive tumor growth) and survival time of the corresponding patients was disclosed. All patients whose tumors were not taken by nude mice are still alive and show no signs of progressive tumor growth at 9 to 34 months after surgery. All but one patient with tumors revealing positive tumor take died within 3 months (resting phase, 3 weeks) or one year (resting phase, 7 to 14 weeks) after surgery. Integrity of hormonal function in benign and malignant xenografts at 4 months posttransplantation could be shown by significantly higher T3 and T4 serum concentrations in animals with benign thyroid tissues (T3, 1.69 +/- 0.13 nmol/liter; T4, 45.69 +/- 2.09 nmol/liter; S.E.) as compared to controls without grafted tissue [T3, 1.29 +/- 0.10 nmol/liter (p less than 0.05); T4, 33.39 +/- 2.71 nmol/liter (p less than 0.05)] and by increased TG serum concentrations in animals receiving benign (TG, 2.70 +/- 1.39 ng/ml) or malignant (e.g., TG in follicular carcinoma, 34.44 +/- 13.83 ng/ml; controls, 0.30 +/- 0.02 ng/ml) thyroid tissue. Thus, we conclude that benign and malignant thyroid xenografts in the nude mouse maintain full morphological and, regarding T3, T4, and TG serum levels, functional integrity for at least 4 months after transplantation.

Quantitative analysis of immunocompetent cells in human normal oral and uterine cervical mucosa, oral papillomas and leukoplakias.

Using monoclonal antibodies reacting with T-cell subpopulations, Langerhans cells and macrophages, the number and distribution of cells of the immune system in normal oral and cervical mucosa was determined and statistically compared with that in oral papillomas and oral leukoplakias. Increased numbers of labelled cells were found in oral leukoplakias and particularly in oral papillomas. In the epithelium of all specimens, Langerhans cells and T-lymphocytes of the suppressor/cytotoxic phenotype as well as of the helper phenotype were seen. Suppressor/cytotoxic and helper T-lymphocytes were in equal numbers in the epithelium of oral papillomas, but were about 2:1 in all other lesions. In normal oral epithelium, macrophages were rare but were in greater numbers in leukoplakias and papillomas. In the connective tissue of all lesions, more labelled cells were present than in epithelium with T-lymphocytes predominant. Although Langerhans cells were rare in connective tissue, many were seen in oral papillomas.

[Surgery for stomach cancer in patients over 70]. / Die Chirurgie des Magenkarzinoms beim Patienten nach dem 70. Lebensjahr.

Among a total of 1038 operations for early and advanced gastric cancer, 257 patients were older than 70 years. The resection rate in this group was 64.2%, 95 subtotal and 70 total gastrectomies were performed. Postoperative complications were caused primarily by concomitant respiratory and cardiac diseases, whereas the overall operative mortality amounted to 16.9%. Depending on the stage of tumour development a 5-year survival rate of 17.7% could be obtained. This rate increased to 27.2% after subtotal or total gastrectomies. The choice of surgical procedures for gastric cancer does not show any principal differences between young and old persons; thus, the use of individual and liberal criteria for total gastrectomy can be justified even in the aged.