Multidisciplinary evaluation of rat renal cell carcinoma

The rat renal cell carcinoma system as described by deVere White and Olsson in 1980 is used widely as a model for its human counterpart. The tumor arose spontaneously in a male Wistar Lewis rat and its behaviour has been shown to be stable during multiple passages. We have compared this tumor with the human renal cell carcinoma using a multidisciplinary approach. Light microscopy and electron microscopy showed a great resemblance of this rat tumor to a human renal cell carcinoma of the clear cell type with the ultrastructural presence of desmosomes. With the use of tissue specific antibodies against intermediate filament proteins, it could be shown that their expression is comparable to human renal cell carcinoma, i.e. coexpression of vimentin and different cytokeratins in the tumor cells. The cells could also be shown to contain cytokeratin 18. An aneuploid cell population in the tumor, expressing both vimentin and keratin, could be characterized by DNA flow cytometry in double labeling experiments. Comparison of normal and malignant rat kidney tissue by Northern blot analysis revealed increased levels of vimentin mRNA. In conclusion, this tumor model seems to have several histological and biological properties in common with the human renal tumor.     

Mitochondrial creatine kinase: a major constituent of pathological inclusions seen in mitochondrial myopathies.

Overaccumulation of abnormally organized mitochondria in so-called "ragged-red" skeletal muscle fibers is a morphological hallmark of mitochondrial myopathies, in particular of mitochondrial encephalomyopathies. Characteristic for the abnormal mitochondria is the occurrence of highly ordered crystalline inclusions. Immuno-electron microscopy revealed that these inclusions react heavily with specific antibodies against mitochondrial creatine kinase (Mi-CK). Image processing of selected crystalline inclusions, sectioned along the crystallographic b, c planes, resulted in an averaged picture displaying an arrangement of regular, square-shaped particles with a central cavity. The overall appearance, dimensions, and symmetry of these building blocks are very reminiscent of single isolated Mi-CK octamers. Taking these findings together, it is concluded that Mi-CK octamers indeed represent the major, if not the only, component of these mitochondrial inclusions.     

Educating and Training a Workforce for Nutrition in a Post-2015 World

Nearly all countries in the world today are burdened with malnutrition, manifesting as undernutrition, micronutrient deficiencies, and/or overweight and obesity. Despite some progress, efforts to alleviate malnutrition are hampered by a shortage in number, skills, and geographic coverage, of a workforce for nutrition. Here, we report the findings of the Castel Gandolfo workshop, a convening of experts from diverse fields in March 2014 to consider how to develop the capacity of a global cadre of nutrition professionals for the post-2015 development era. Workshop participants identified several requirements for developing a workforce for nutrition, including an ability to work as part of a multisectoral team; communication, advocacy, and leadership skills to engage decision makers; and a set of technical skills to address future challenges for nutrition. Other opportunities were highlighted that could immediately contribute to capacity development, including the creation of a consortium to link global North and South universities, online training modules for middle managers, and practical, hands-on experiences for frontline nutrition workers. Institutional and organizational support is needed to enable workshop recommendations on education and training to be effectively implemented and sustained. The findings from the Castel Gandolfo workshop can contribute to the delivery of successful nutrition-relevant actions in the face of mounting external pressures and informing and attaining the forthcoming Sustainable Development Goals.     

Activity of the stimulatory guanine nucleotide-binding protein is reduced in erythrocytes from patients with pseudohypoparathyroidism and pseudopseudohypoparathyroidism: biochemical, endocrine, and genetic analysis of Albright's hereditary osteodystrophy in six kindreds

Multiple hormone resistance in many patients with pseudohypoparathyroidism (PHP) type Ia and Albright's hereditary osteodystrophy (AHO) is associated with deficient activity of the stimulatory guanine nucleotide-binding protein (Gs) of adenylate cyclase. To study further the relationship of deficient Gs activity to hormone resistance, we evaluated endocrine function and measured Gs activity of erythrocyte membranes from AHO patients with clinical hormone resistance (PHP type Ia) and from family members with AHO alone (pseudopseudohypoparathyroidism). The results of erythrocyte membrane Gs determinations were compared to those of unaffected relatives and normal subjects. Patients with pseudopseudohypoparathyroidism (pseudoPHP) had reductions in erythrocyte membrane Gs activity comparable to those in patients with PHP type Ia [43.4 +/- 11.9% (+/- SD) for PHP type Ia vs. 47.8 +/- 9.5% for pseudoPHP]. However, in contradistinction to patients with PHP type Ia, individuals with pseudoPHP did not have obvious endocrine dysfunction. Although deficient Gs activity appears to play an important role in the pathogenesis of these disorders, it is possible that Gs deficiency must be combined with other factors that limit cAMP production to cause clinically overt endocrine disease.     

CD147 is a regulatory subunit of the gamma-secretase complex in Alzheimer's disease amyloid beta-peptide production

gamma-Secretase is a membrane protein complex that cleaves the beta-amyloid precursor protein (APP) within the transmembrane region, after prior processing by beta-secretase, producing amyloid beta-peptides Abeta(40) and Abeta(42). Errant production of Abeta-peptides that substantially increases Abeta(42) production has been associated with the formation of amyloid plaques in Alzheimer's disease patients. Biophysical and genetic studies indicate that presenilin-1, which contains the proteolytic active site, and three other membrane proteins [nicastrin, anterior pharynx defective-1 (APH-1), and presenilin enhancer-2 (PEN-2)] are required to form the core of the active gamma-secretase complex. Here, we report the purification of the native gamma-secretase complexes from HeLa cell membranes and the identification of an additional gamma-secretase complex subunit, CD147, a transmembrane glycoprotein with two Ig-like domains. The presence of this subunit as an integral part of the complex itself was confirmed through coimmunoprecipitation studies of the purified protein from HeLa cells and of solubilized complexes from other cell lines such as neural cell HCN-1A and HEK293. Depletion of CD147 by RNA interference was found to increase the production of Abeta peptides without changing the expression level of the other gamma-secretase components or APP substrates whereas CD147 overexpression had no statistically significant effect on Abeta-peptide production, other gamma-secretase components or APP substrates, indicating that the presence of the CD147 subunit within the gamma-secretase complex down-modulates the production of Abeta-peptides.     

A novel mutation of KCNJ11 gene in a patient with permanent neonatal diabetes mellitus

A 4-month-old male baby was diagnosed with Permanent Neonatal Diabetes Mellitus. We identified a novel missense heterogeneous mutation in the KCNJ11 gene at codon 167 (aTC → tTC) in a region that corresponds to a predicted intracellular gate of the ATP-sensitive potassium channel.     

Studies on the interactions of tobacco leaf and tobacco smoke constituents and monoamine oxidase

Studies have demonstrated that smokers have lower levels of brain monoamine oxidase (MAO) A and B activity and lower MAO-B platelet activity than non-smokers. Recent speculations suggest that in addition to nicotine, tobacco components which are MAO inhibitors, may contribute to some tobacco related psychopharmacological effects. Furthermore, epidemiological evidence indicates a lower incidence of Parkinson’s disease in smokers than in non-smokers. This relationship also might be linked to MAO inhibition. There intriguing observations prompted studies on the effects of tobacco leaf and tobacco smoke constituents on MAO activity. Studies reported here demonstrate that crude hexane tobacco leaf and hexane and aqueous leaf extracts have MAO inhibitory properties. Rat brain mitochondrial MAO-A and MAO-B activity are not altered following continuous 28 day exposure (osmotic minipump) to two tobacco alkaloids, (S)-nicotine or (R,S)-N-methylanatabine. However, earlier studies in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treated parkinsonian C57BL/6 mouse model have provided indirect evidence that the tobacco derived 2,3,6-trimethyl-1,4-naphthoquinone (an MAO-A and B inhibitor) is effective in inhibiting MAO-B in vivo and is neuroprotective. Results reported here from more extensive tobacco leaf extractions provide evidence for three additional compounds with MAO-B inhibitory properties. One contains a chromone system, another a polyunsaturated macrocycle and the third we have identified as farnesylacetone. These findings provide support to the thesis that components of tobacco smoke may be responsible for the inhibition of brain MAO-A and brain and platelet MAO-B in human smokers.     

Glial-derived neurotropic factor and RET gene expression in normal human anterior pituitary cell types and in pituitary tumors

Glial-derived neurotropic factor (GDNF) signaling is mediated through a 2-component system consisting of the so-called GDNF receptor-alpha (GFRalpha1), which binds to GDNF. This complex activates the tyrosine kinase receptor RET. In this paper we demonstrate GDNF, GFRalpha1, and RET mRNA and protein expression in the human anterior pituitary gland. Double immunohistochemistry of anterior pituitary sections showed GDNF immunoreactivity in more than 95% of somatotrophs and to a lesser extent in corticotrophs (20%); it was almost absent in the remaining cell types. Also, although more than 95% of somatotrophs were stained for RET, no positive immunostaining could be detected in other cell types. Furthermore, we have looked for GDNF and RET in human pituitary adenomas of various hormonal phenotypes. Strong positive immunostaining was found for c-RET in all of the GH-secreting adenomas screened as well as in 50% of ACTH-producing adenomas. Positive immunostaining for GDNF was found in all of the GH-secreting adenomas and in 10% of the corticotropinomas. Lastly, we found strong positive immunostaining for GFRalpha1 in 90% of the somatotropinomas and 50% of the corticotropinomas as well as in 1 of 8 prolactinomas and 1 of 13 nonfunctioning adenomas. All of the remaining pituitary tumors screened were negative for RET, GDNF, and GFRalpha1. This study indicates that GDNF may well be acting in the regulation of somatotroph cell growth and/or cell function in the normal human anterior pituitary gland. The expression of RET in all of the somatotropinomas and in 50% of the ACTH-producing tumors implies that GDNF and RET could be involved in the pathogenesis of pituitary tumors.     

Two novel mutations in the gene encoding thyroxine-binding globulin (TBG) as a cause of complete TBG deficiency in Taiwan

OBJECTIVE: Thyroxine-binding globulin (TBG) encoded by the TBG gene on chromosome Xq22 is the major transport protein, carrying approximately 75% of circulating T4. Inherited defects in TBG are associated with three phenotypes based on the level of TBG in serum of affected hemizygous males: complete TBG deficiency (TBG-CD), partial TBG deficiency (TBG-PD) and TBG excess (TBG-E). In this study, we report two unrelated Han Chinese males with complete TBG deficiency who carry different mutations in the TBG gene. PATIENTS: Two index cases of Han males who were diagnosed as having TBG deficiency on the basis of undetectable serum TBG and an additional 75 (50 males and 25 females) normal Han Chinese. MEASUREMENT: Serum thyroid hormones were measured by chemiluminescent immunoassay, thyroid autoantibodies by an agglutination test, and TSH receptor antibody and TBG by radioimmunoassay. Genomic DNA extraction, polymerase chain reaction (PCR) and DNA sequence analysis of the TBG gene were performed with standard methods. RESULTS: One index case had one missense mutation in his copy of the gene, a G --> A transition in codon 52 that results in the replacement of serine by asparagine, and a known polymorphism in codon 283 (TTG --> TTt) that results in the replacement of leucine by phenylalanine. The allelic frequency of TBG-Poly allele in 75 normal Han Chinese (100 chromosomes) was 31%. A second index case was hemizygous for a nonsense mutation in codon 280 of exon 3 (TGG --> TGa). This mutation, located in the C-terminal of TBG, predicts a markedly truncated protein. CONCLUSIONS: This is the first report of complete thyroxine-binding globulin deficiency (TBG-CDT1 and TBG-CDT2) due to TBG gene mutations in Taiwan.