Transcriptional regulation by the phosphorylation-dependent factor CREB

The transcription factor CREB -- for 'cyclic AMP response element-binding protein' -- functions in glucose homeostasis, growth-factor-dependent cell survival, and has been implicated in learning and memory. CREB is phosphorylated in response to various signals, but how is specificity achieved in these signalling pathways?

Familial isolated parathyroid adenoma in a consanguineous family

The 23-year-old Caucasian male propositus presented with symptomatic hypercalcemia, hypophosphatemia and normocalciuria for 2 months. His 29-year-old brother had undergone an operation for recurrent parathyroid adenoma at age 26 and 28. No other member of the family was affected. His father and mother were second-degree relatives. Laboratory studies showed primary hyperparathyroidism (pHPT), while the remaining endocrine studies and genetic testing for multiple endocrine neoplasia 1 and 2A were normal. Technetium-cardiolite scintigraphy and ultrasound scans revealed a parathyroid mass at the left lower neck. Apart from bilateral hearing loss due to gentamicin treatment as a pre-term child, the patient was in of good health. Signs or symptoms of other endocrinopathies were absent. The patient was referred for parathyroidectomy with subsequent autotransplantation of the remaining glands into his sternocleidomastoid muscle. Histological examination revealed an adenoma with oncocytic differentiation, similar to that seen in his brother. The disease may follow a recessive mode of inheritance or may be due to a dominant germ-cell mutation in one of the parents. The presented case may ultimately help in elucidating the molecular genetic basis of this rare form of pHPT.

Comparative analysis of ras proto-oncogene mutations in selected mammalian tumors

Point mutations within ras proto-oncogenes are frequently detected in human malignancies and in different types of experimentally induced tumors in animals. In contrast to findings in experimental animal models of carcinogenesis, little is known about the incidence of ras mutations in naturally occurring animal tumors. In the present study, we investigated whether point mutations, particularly within the mutational hot-spot codons 12, 13, and 61, occur at comparable frequencies in human malignancies and spontaneously occurring tumors in other mammalian species. Two hundred seventy-nine of the most frequent canine and feline neoplasms were analyzed for changes in mutational hot-spot regions of the N-, Ki-, and Ha-ras genes. DNA fragments from exons 1 and 2 of all three ras genes were amplified by polymerase chain reaction, and the presence of point mutations was assessed by single-strand conformation polymorphism analysis and direct sequencing of amplified products. Only one sample, a case of canine melanoma, exhibited an Ha-ras mutation. Thus, our data strongly suggested that ras mutations at the hot-spot loci are apparently very rare and do not play a major role in the pathogenesis of the spontaneously occurring canine and feline tumors investigated. These observations were in marked contrast to those in experimental rodent models of carcinogen-induced mammary and skin tumors that described a consistent association with Ha- or Ki-ras activation. The role of ras oncogene activation in related human malignancies therefore cannot be readily inferred from studies of experimental carcinogenesis in animal models.

Chiral beta-cyclodextrin-based polymer supports prepared via ring-opening metathesis graft-polymerization

A series of norborn-2-ene-derivatized beta-cyclodextrins (beta-CDs), 6-O-(norborn-2-ene-5-carboxyl)-beta-CD (1), tetrakis(6-O-norborn-2-ene-5-carboxyl)-beta-CD (2), (3), 6-O-(6-norborn-2-ene-5-car-6-O-(7-oxanorborn-2-ene-5-carboxyl)-beta-CD bonylaminohexoyl)-beta-CD (4), 6-O-(norborn-2-ene-5-ylmethoxymethylsilyl)-beta-CD (5), tris(6-O-norborn-2-ene-5-ylmethoxymethylsilyl)-beta-CD (6), tetrakis(6-O-norborn-2-ene-5-ylmethoxymethylsilyl)-beta-CD (7) and hexakis(6-O-norborn-2-ene-5-ylmethoxymethylsilyl)-beta-CD (8), have been synthesized. Compounds 1-3 were prepared via reaction of beta-CD with norborn-2-ene-5-carboxylic chloride and 7-oxanorborn-2-ene-5-carboxylic chloride, respectively; compounds 5-8 were synthesized from norborn-2-ene-5-yl-methyldichlorosilane and beta-CD, respectively. Compound 4 was accessible by reaction of norbom-2-ene-5-carboxylaminohexoyl chloride with beta-CD. Compounds 1-8 were surface grafted onto norborn-2-ene-derivatized silica-based supports using ring-opening metathesis polymerization employing the ruthenium-based initiator bis(tricyclohexylphosphino)benzylideneruthenium dichloride [Cl2Ru(CHC6H5)(PCy3)2, Cy=cyclohexyl, 9]. Generally speaking, the resulting chiral stationary phases (CSPs) I-VIII may be prepared with high reproducibility and may be used within a pH of 2-10. Thus, relative standard deviations (sigman-1) of the mean resolution (Rs) are <7%. The CSPs were used for the enantioselective separation of beta-blockers, N-dansyl-, N-3,5-dinitrobenzoyl- and Fmoc-protected amino acids and were characterized in terms of chemical stability, selectivity (alpha') and resolution (Rs). Additionally, the role of the spacer as well as influences of capacity and the degree of substitution of the beta-CD moiety on the separation characteristics were determined.

Influences of surface chemistry on the separation behavior of stationary phases for reversed-phase and ion-exchange chromatography: a comparison of coated and grafted supports prepared by ring-opening metathesis polymerization

A series of poly(norborn-2-ene) (poly-NBE), poly(7-oxanorborne-2-ene-5,6-dicarboxylic acid) (poly-ONDCA), as well as poly(norborn-2-ene-co-7-oxanorborne-2-ene-5,6-dicarboxylic acid) (poly-NBE-co-ONDCA) based silica supports were prepared via ring-opening metathesis polymerization (ROMP) using both coating and grafting techniques. Poly-NBE-grafted and poly-NBE-coated supports were used for the reversed-phase separation of phenols; poly-NBE, poly-ONDCA as well as poly-NBE-co-ONDCA-grafted supports were used for comparative studies on the separation of a series of anilines and lutidines. As expected, grafted supports possess superior separation capabilities compared to their coated analogues. Compared to pure poly-NBE- and poly-ONDCA-grafted stationary phases, supports consisting of poly-NBE-co-ONDCA block-copolymers possess both hydrophobic and ion-exchange sites and represent optimum stationary phases for the separation of isomeric basic analytes.

Comparative studies in the promoter and exon 1 regions of tumour suppressor p53 in several mammalian species: absence of mutations in a panel of spontaneous domestic animal tumours

Tumour suppressor p53 is critical in a broad panel of tumour types in human, mouse and other mammals. Regions of the promoter and exon 1 play an important role in expression of p53. In the present study, the DNA sequences of promoter and exon 1 regions of four domestic animal species (dog, cat, horse and cattle) are determined and compared with experimental rodents (mouse, rat and hamster) and man. A broad panel of tumour types have been investigated for mutations in this regulatory area in 90 canine, 136 feline, 25 equine and 10 bovine patients. No mutation was detected in any of the tumours analysed.

Free and protein bound leptin are distinct and independently controlled factors in energy regulation

AIMS/HYPOTHESIS

Leptin exerts important regulating effects on energy homeostasis and could have a central role in our understanding of obesity, diabetes mellitus and the metabolic syndrome. Leptin circulates in a free and protein bound form. The aim of the present study was to test whether both fractions of the leptin system can be selectively regulated and thus serve independent physiological roles.

METHODS

Using specific radioimmunoassays we measured both leptin components in relation to BMI in healthy subjects before and after weight reduction and in hyperthyroid patients during correction of thyrotoxicosis. In the latter group body composition and resting energy expenditure was monitored. In addition, we measured serum and cerebrospinal fluid concentrations of free and bound leptin in patients with neurological disorders.

RESULTS

Under all conditions free leptin concentrations reflected body fat mass. Bound leptin concentrations decreased during weight reduction but also after treatment of hyperthyroidism despite an increase in fat mass. Direct measurement of resting energy expenditure and bound leptin in hyperthyroid patients and under thyrostatic treatment showed a significant positive correlation of both variables. In contrast to free leptin whose transport into the cerebrospinal fluid appears to be saturated at low physiological concentrations of serum free leptin, bound leptin concentrations in the cerebrospinal fluid increased in parallel to serum concentrations over the whole physiologically relevant range.

CONCLUSION/INTERPRETATION

Our data indicate a distinct role of free and bound leptin in the feedback regulating energy intake and expenditure and could have important implications for our understanding of the physiology and pathophysiology of leptin-dependent signalling.

Absence of S100A4 (mts1) gene mutations in various canine and feline tumours. Detection of a polymorphism in feline S100A4 (mts1)

Ninety canine and 101 feline tumours of various types were investigated for gene mutations in the coding regions of the metastasis-associated gene S100A4 (mts1). No gene mutations were present in the analysed genomic area. A widespread histidine/tyrosine polymorphism was detected in codon 17 of S100A4.

Absence of p21 WAF1 and p27 kip1 gene mutations in various feline tumours

The coding regions of tumour suppressor and cell cycle regulatory genes p21 WAF1 and p27 Kip1 were investigated in 101 feline tumours of various types. No damaging mutations were present in the analysed areas of the genes.

Presence of p53 mutations in feline neoplasms

A region from exon 4 to 8 of the tumour suppressor gene p53 was analysed in 60 feline tumours (30 fibrosarcomas, seven malignant histiocytomas, three lymphosarcomas, five basal cell tumours, five squamous cell carcinomas, two adenocarcinomas of tubular skin glands, one undifferentiated carcinoma of the skin, seven mammary carcinomas). Missense mutations were detected in two fibrosarcomas, one malignant fibrous histiocytoma, the undifferentiated carcinoma of the skin and one mammary carcinoma. One nonsense mutation was detected in one fibrosarcoma and one deletion/frameshift-mutation was observed in one squamous cell carcinoma.

Incidental detection of familial medullary thyroid carcinoma by calcitonin screening for nodular thyroid disease

Serum calcitonin screening has recently been found to be a useful supplement to fine-needle aspiration biopsy, ultrasound and radionuclide imaging in the evaluation of thyroid nodules. We describe a case where introduction of routine calcitonin screening in nodular thyroid disease led to the detection of a family with medullary thyroid carcinoma. The benefits and problems of basal and stimulated serum calcitonin testing and ret-proto-oncogene mutation studies are exemplified and we discuss the appropriate use and interpretation of these tests. We conclude that routine basal serum calcitonin measurement in nodular thyroid disease and thoughtful use of ret-mutation analysis is cost-effective in detecting medullary thyroid carcinoma and multiple endocrine neoplasia type II.

Extended recombinant bacterial ghost system

Controlled expression of cloned PhiX174 gene E in Gram-negative bacteria results in lysis of the bacteria by formation of an E-specific transmembrane tunnel structure built through the cell envelope complex. Bacterial ghosts from a variety of bacteria are used as non-living candidate vaccines. In the recombinant ghost system, foreign proteins are attached on the inside of the inner membrane as fusions with specific anchor sequences. Ghosts have a sealed periplasmic space and the export of proteins into this space vastly extends the capacity of ghosts or recombinant ghosts to function as carriers of foreign antigens. In addition, S-layer proteins forming shell-like self assembly structures can be expressed in candidate vaccine strains prior to E-mediated lysis. Such recombinant S-layer proteins carrying foreign epitopes further extend the possibilities of ghosts as carriers of foreign epitopes. As ghosts have inherent adjuvant properties, they can be used as adjuvants in combination with subunit vaccines. Subunits or other ligands can also be coupled to matrixes like dextran which are used to fill the internal lumen of ghosts. Oral, aerogenic or parenteral immunization of experimental animals with recombinant ghosts induced specific humoral and cellular immune responses against bacterial and target components including protective mucosal immunity. The most relevant advantage of recombinant bacterial ghosts as immunogens is that no inactivation procedures that denature relevant immunogenic determinants are employed in this production. This fact explains the superior quality of ghosts when compared to other inactivated vaccines. The endotoxic component of the outer membrane does not limit the use of ghosts as vaccine candidates but triggers the release of several potent immunoregulatory cytokines. As carriers, there is no limitation in the size of foreign antigens that can be inserted in the membrane and the capacity of all spaces including the membranes, peri-plasma and internal lumen of the ghosts can be fully utilized. This extended recombinant ghost system represents a new strategy for adjuvant free combination vaccines.

Cytogenetic variation in six cases of feline mammary tumours

Mammary carcinomas of six feline patients were subjected to karyotypic analysis. A broad variation in the numerical and structural alterations was evident. None the less, several repeatedly occurring alterations were observed.

Novel canine tumour suppressor gene p53 mutations in cases of skin and mammary neoplasms

Exons 4 to 8 of the tumour suppressor gene p53 were analysed in 25 skin and 25 mammary tumours of 50 dogs. A 1 bp deletion (ACC-->AC) was detected in codon 89 in exon 4 in a squamous cell carcinoma. A missense mutation CGC-->CAC (arginine-->histidine) was present in codon 162 in exon 5 in a mammary adenocarcinoma. Moreover, a silent mutation occurred in codon 103 (serine) of exon 4 in a mammary adenoma. The somatic nature of the three mutations was demonstrated.

Expression of wild-type ret, ret/PTC and ret/PTC variants in papillary thyroid carcinoma in Germany

INTRODUCTION

Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy. Although the clinical course is usually rather benign, a subset of tumors is more aggressive. The ret/PTC oncogene was found only in PTC, with varying frequencies of up to 30%. Recently, two new variants of ret/PTC could be identified in post-Chernobyl PTCs, which raised the possibility that the prevalence of ret/PTC in non-radiation-induced PTCs might be higher than previously described. Normal thyroid cells do not express wild-type ret, but there is evidence that ret activation from any cause, including wild-type ret, occurs in more than a half of papillary tumors.

METHODS

We used reverse transcription polymerase chain reaction and sequencing to examine wild-type ret and all five forms of ret/PTC known today in 99 PTCs from Hannover, Dusseldorf, Halle and Regensburg. Our method could also detect other variants within the known breakpoint regions. The presence of the ret tyrosine-kinase domain was examined by immunohistochemistry.

RESULTS

Seven PTC1-positive tumors and one PTC3-positive tumor (8%), but none with the new variants or other variants of PTC1, 2 or 3 could be detected. Of 43 tumors examined, 20 showed expression of wild-type ret mRNA and staining of ret protein located predominantly to the cell membrane.

CONCLUSION

Variants of ret/PTC do not substantially contribute to non-radiation-related ret/PTC-positive tumors, and the prevalence of ret/PTC in Germany is low in contrast to the high rate of wild-type ret expression. Thus, expression of wild-type ret should be examined for pathogenic, prognostic and possible therapeutic implications.

Cytogenetic, ras, and p53: studies in cases of canine neoplasms (hemangiopericytoma, mastocytoma, histiocytoma, chloroma)

Four case reports of mesenchymal neoplasms showing chromosomal abnormalities are presented. In a case of hemangiopericytoma trisomy 2 and centric fusion 19;21 were present. In a mastocytoma a deleted chromosome 35 was seen. A homogeneously staining region (HSR) on chromosome 1 was detected in a histiocytoma. Trisomy 5 and monosomy 31 were observed in a case of granulocytic sarcoma (chloroma). The lack of mutations in exons 1 and 2 of oncogenes N-ras, K-ras, and H-ras and exons 5, 6, 7, and 8 of tumor suppressor gene p53 in these four patients and in a larger series of investigated dogs (25 hemangiopericytomas, 12 mastocytomas, and 8 histiocytomas) is highlighted.

[Interactions between the immune system and the psyche]

Compared to well documented studies on immunosuppression "psychologically induced immunoenhancement" is a rather neglected topic in medical literature and research, even in the new established field of psychoneuroimmunology. Starting with the premise that research questions emanating from this field and from behavioural medicine may provide critical information for understanding the phenomena of immunomodulation, evidence and illustrations of psychologically induced immunoenhancement are provided in the context of psychosocial neuroimmunomodulation. Distress-reducing interventions such as progressive relaxation training, imagery, experimentally induced short-term positive mood states and mirthful laughter enhances various aspects of immune functions, i.e., primarily the phylogenetically old paraspecific parameters. Additionally, a larger variety of emotional/psychosocial factors with potentially but yet unproved immunoenhancing effects seems to exist. In particular, enhancement of phagocytosis, NK cell and T cell response to phytohemagglutinin, decrease in the number of suppressor/cytotoxic T cells and increase in the number of circulating T helper/inducer cells in peripheral blood, and enhancement of spontaneous lymphocyte blastogenesis as well as cytokines have all been shown to be associated with the above mentioned intervention techniques.

Novel p53 tumour suppressor mutations in cases of spindle cell sarcoma, pleomorphic sarcoma and fibrosarcoma in cats

Twenty feline neoplasms were sequenced in the region from exons 5 to 8 for the presence of tumour suppressor gene p53 mutations. In a spindle cell sarcoma of the bladder, a missense mutation (codon 164 AAG-->GAG, lysine-->glutamic acid) in exon 5 was detected. In a pleomorphic sarcoma, a 23 bp deletion involving the splicing junction between intron 5 and exon 6 was observed. In a fibrosarcoma, a 6 bp deletion of p53 covering 2 bp of exon 7 and 4 bp of intron 7, including the splicing junction, was found. The study demonstrates three new p53 mutations in different types of sarcomas in cats.

High sequence similarity within ras exons 1 and 2 in different mammalian species and phylogenetic divergence of the ras gene family

We have determined the canine and feline N-, K-, and H-ras gene sequences from position +23 to +270 covering exons I and II which contain the mutational hot spot codons 12, 13, and 61. The results were used to assess the degree of similarity between ras gene DNA regions containing the critical domains affected in neoplastic disorders in different mammalian species. The comparative analyses performed included human, canine, feline, murine, rattine, and, whenever possible, bovine, leporine (rabbit), porcelline (guinea pig), and mesocricetine (hamster) ras gene sequences within the region of interest. Comparison of feline and canine nucleotide sequences with the corresponding regions in human DNA revealed a sequence similarity greater than 85% to the human sequence. Contemporaneous analysis of previously published ras DNA sequences from other mammalian species showed a similar degree of homology to human DNA. Most nucleotide differences observed represented synonymous changes without effect on the amino acid sequence of the respective proteins. For assessment of the phylogenetic evolution of ras gene family, a maximum parsimony dendrogram based on multiple sequence alignment of the common region of exons I and II in the N-, K-, and H-ras genes was constructed. Interestingly, a higher substitution rate among the H-ras genes became apparent, indicating accelerated sequence evolution within this particular clade. The most parsimonious tree clearly shows that the duplications giving rise to the three ras genes must have occurred before the mammalian radiation.

Expression of Ret/PTC1, -2, -3, -delta3 and -4 in German papillary thyroid carcinoma

Ret/PTC oncogene has been described with a frequency of 2.5-30% in papillary thyroid carcinomas. We examined the expression of ret/PTC in 99 German papillary thyroid carcinomas, including two recently described new variants of ret/PTC3 and identified eight ret/PTC-positive tumours (8%) but none with the new variants.

Reciprocal translocation in a case of canine basal cell carcinoma

A case of basal cell carcinoma in a 10-year-old spaniel dog was analysed cytogenetically. A reciprocal translocation t(10;35) was detectable.