Preoperative endosonographic staging of cancer of the cardia

BACKGROUND

To evaluate the diagnostic accuracy of endosonography (ES) in a prospective series of cancer of the cardia.

METHODS

Thirty-five patients with cancer of the cardia were investigated by ES; 29 underwent surgery. ES staging for the surgery patients was compared with histopathologic findings. Tumors were staged according to the 1987 TNM classification.

RESULTS

ES had a diagnostic accuracy of 79% for the T category, 79% for the N category, 89% for the M category, and 72% for prognostic TNM staging.

CONCLUSION

ES is an excellent paraclinical modality for the staging of local-regional spread of cancer of the cardia and a useful complement to computed tomography for evaluation of these tumors.

Interlaboratory comparison of polymerase chain reaction for the detection of Toxoplasma gondii DNA added to samples of amniotic fluid

To investigate the accuracy of the polymerase chain reaction (PCR) method for the detection of Toxoplasma gondii in clinical specimens, aliquots of amniotic fluid to which known amounts of Toxoplasma gondii DNA had been added were tested by five European Centres. Four laboratories were able to detect DNA at levels equivalent to ten tachyzoites or less, including two that detected DNA equivalent to a single parasite. Two laboratories erroneously found one of eight negative control samples to be positive. These findings confirm that the high level of sensitivity associated with the PCR method can be readily achieved under routine laboratory conditions, but they also underscore the potential for both false-positive and false-negative findings to occur. Furthermore, the results confirm the urgent need for an external quality assurance scheme to support laboratories employing PCR in a clinical context for the detection of Toxoplasma gondii.

Divergent selection for high or low growth rate modifies the response of muscle cells to serum or insulin-like growth factor-I in vitro

Genetic differences in growth potential could result from changes in the levels of growth stimulatory factors or in the response of target tissues. The latter possibility was tested in adult myoblasts prepared from chickens selected for high (HG) or low growth rate (LG). Stimulation of [3H]-thymidine incorporation into DNA by serum was of higher amplitude in HG than LG muscle cells irrespective of whether the cell preparations were enriched in myoblasts or fibroblasts. HG myoblasts were also more responsive to insulin-like growth factor-I (IGF-I) in terms of [3H]-thymidine incorporation. IGF analogues with a reduced affinity for IGF binding proteins gave similar results suggesting that activity of binding proteins could not explain the difference between cells from the HG and LG lines. This difference was restricted to the proliferative stage because in myotubes, basal or IGF-I stimulated glucose and amino acid transports, tyrosine incorporation and protein degradation were not different.

A novel G protein-coupled P2 purinoceptor (P2Y3) activated preferentially by nucleoside diphosphates

A partial cDNA was isolated by hybridization screening of an embryonic chick brain library for P2Y purinoceptors. After extension to full length, it revealed an open reading frame that encoded a protein, P2Y3, of 328 amino acids that is nearest in sequence identity to the G protein-coupled P2 purinoceptors obtained by DNA cloning. Expression of P2Y3 in cRNA-injected Xenopus oocytes confirmed that this cDNA encodes a member of the metabotropic purinoceptor family, with a novel order for the relative activities of nucleotides. At 100 microM concentrations, ADP gave the highest activity, and UTP and UDP were also strongly active. When expressed in the human T cell line Jurkat, P2Y3 mediated transient increases in intracellular Ca2+ in response to various nucleotides. Again, an unusual agonist rank order was revealed, with uridine nucleotides being more potent than adenosine nucleotides and UDP being the most potent agonist tested (half-maximal concentration, 0.13 microM) and 10-fold more potent than UTP. 2-Methylthlo-ATP was of relatively low activity in both systems. The receptor transcript is expressed in brain, spinal cord, kidney, and lung and is highly abundant in the spleen but not in other peripheral tissues that we tested. The results indicated that P2Y3 is a previously unknown P2 purinoceptor subtype with a preference for nucleoside diphosphates.

The pathogenesis of multiple sclerosis: reconsideration of the role of viral agents and defence mechanisms

Numerous ubiquitous ribonucleic acid and deoxyribonucleic acid viruses, inducing acute, monophasic infections (mostly childhood diseases) have been considered as potential causes of multiple sclerosis. The present hypothesis reconsiders the role of the viral agent: not the virus, but the reaction of the defense system to the viral persistence, appearing after the acute phase, is postulated as a key factor. A prerequisite of multiple sclerosis is polygenetically determined or acquired immunodeficiency; the defense system is not able to stop repeated viral reactivations induced by a set of exogenous and/or endogenous factors. Thus, an aberrant virus production can appear repeatedly. If the virus spreads from primary target--the lymphoreticular system--into the central nervous system, the multiple sclerosis process can be initiated. Activated T cells and endothelial cells serve as first-host cells. Their infection triggers a set of reactive events: multiple microthrombosis and inflammation play a key role, both of which can result in nonspecific degradation of the myelin. An increased release of myelin antigens induces a homeostatic autoimmunity. Long-term repetition of the shifts and the infection of inflammatory cells can lead to disturbances in self-tolerance. A dysregulated pathological autoimmunity can develop, which acts as a main effector of the specific demyelination.

IgG1 and IgG2 antibody responses to Plasmodium falciparum exoantigens correlate inversely and positively, respectively, to the number of malaria attacks

In Manarintsoa, near Antananarivo, Madagascar, two groups of patients were defined in terms of malaria clinical immune status: Group MA+ consisted of 36 patients who suffered from between one to four malaria attacks (MA) during the 20-week study, and Group MA- who comprised of 48 persons who did not have any malaria attacks during this time. In group MA+, IgM and IgG antibody levels to Plasmodium falciparum exoantigens (E-Ag) were inversely related to the number of malaria attacks. The level of IgM antibodies were significantly higher in group MA+. In contrast, IgG, IgG1, IgG2, IgG3 and IgG4 antibodies to E-Ag were significantly higher in group MA-. The level of IgG1 antibodies was inversely correlated, and IgG2 antibodies were positively correlated to the number of malaria attacks.

[Homocysteine, a less well-known risk factor in cardiac and vascular diseases]

Hyperhomocyst(e)mia (Hcy) negatively influences vascular endothelium and coagulation factors. Association of Hcy with premature arteriosclerosis (rather than atherosclerosis), stroke, myocardial infarction and peripheral arterial and venous disease was proved in clinical and epidemiological studies, even as the association with conventional risk factors like age, male sex, smoking, hypertension and hypercholesterolemia. Vitamin substitution of folates, vitamin B6 and B12 decreases Hcy blood levels, however definite evidence is still lacking, whether it results in lower incidence and mortality from cardiovascular diseases. Therefore clinical and epidemiological studies are necessary. Before the grant-application we proved in a pilot study significantly higher Hcy levels in 97 patients with manifest ischaemic heart disease than in 37 controls.

Isolation and characterization of Muscovy (Cairna moschata) duck insulin

Ducks (Anatidae Family, Anseriform order) are divided in two genera: Pekin duck (Anasplatyrhynchos genus) and Muscovy duck (Cairina moschata genus) and differ for their number of liver insulin receptors (despite rather similar plasma insulin levels). The possibility that the presence of different endogenous insulins account for the difference in insulin receptor number between the two duck species led us to purify, sequence and characterize the binding properties of Muscovy duck insulin. The sequence of Muscovy duck insulin (measured mass: 5729.11) was identical to that described in two other species from the Anseriforme order: Pekin duck or goose. The binding affinity of Muscovy duck insulin for rat liver insulin receptors (either membrane bound or solubilized receptors) was lower than that of porcine insulin (0.3), which most likely accounts for the low biological potency of Pekin duck insulin previously described. In contrast, liver receptors from chicken and both duck species exhibited the same affinity for duck and porcine insulin suggesting the presence of specific changes in the structure of binding sites of bird liver insulin receptors. The decrease in the number of insulin receptors in Muscovy duck liver is not therefore the consequence of a change at the level of the insulin molecule itself. As discussed, among bird insulins, the hypoactive "duck type" insulin would have appeared after the hyperactive "chicken type" insulin during the evolution of Aves.

Regulation of the expression of the traM gene of the F sex factor of Escherichia coli

Conjugative F-plasmid transfer is mediated by the transfer (tra) region which encodes nearly 40 genes, 25 of which are essential for this process in Escherichia coli. TraM is required for conjugation and is encoded on a separate operon between the origin of transfer and the traJ gene. The traJ gene product is the positive regulator of transcription of the 30 kb tra operon, the first gene of which is traY. Using primer-extension assays and immunoblots on the F plasmid itself and its derivatives, we demonstrate that F TraM regulates its own expression from two promoters and that it requires TraY as well as expression of the tra operon for maximal traM transcription. traY is the first gene in the tra operon under the control of the TraJ regulator, which is in turn negatively regulated by the antisense RNA, FinP, and the FinO protein. Thus, a control circuit has been established whereby traM is negatively regulated by the FinOP fertility inhibition system through its repression of TraJ expression, which adversely affects transcription of the traY gene.

The Drosophila Polycomb group gene Sex comb on midleg (Scm) encodes a zinc finger protein with similarity to polyhomeotic protein

The Sex comb on midleg (Scm) gene is a member of the Polycomb group (PcG) of genes in Drosophila melanogaster. The PcG genes encode transcriptional repressors required for proper spatial expression of homeotic genes. We report the isolation of new Scm mutations and the molecular characterization of the Scm gene. Scm mRNA is expressed maternally, at peak levels in early embryos and then at lower levels throughout the remainder of development. Scm encodes a putative zinc finger protein of 877 amino acids. Scm protein is similar to polyhomeotic, another member of the PcG, both in the zinc finger region and in a separate C-terminal domain of 60 amino acids, which we term the SPM domain. Sequence analysis of an Scm mutant allele suggests a functional requirement for the SPM domain. Scm protein also bears homology in multiple domains to a mouse protein, Rae-28 (Nomura, M., Takihara, Y. and Shimada, K. (1994) Differentiation 57,39-50) and to a fly tumor suppressor protein, the product of the lethal(3)malignant brain tumor gene (Wismar, J. et al., (1995) Mech. Dev. 53, 141–154). Possible functional relationships among these proteins and potential biochemical roles for Scm protein in PcG repression are discussed.

A new set of primers for the detection of Toxoplasma gondii in amniotic fluid using polymerase chain reaction

A new PCR system including a pair of primers, a probe and an internal control were designed from the B1 gene of Toxoplasma gondii. The system described allowed the detection of less than 10 tachyzoites of the RH strain of T. gondii. Among 21 amniotic fluid samples, this system diagnosed the cases of congenital toxoplasmosis which were simultaneously diagnosed using mice inoculation, in vitro culture, and serology from both amniotic fluid and fetal blood. These results show that these new primers allow for a highly sensitive detection of T. gondii DNA.

Alteration of lymphocyte membrane phospholipids and intracellular free calcium concentrations in hyperlipidemic subjects

Hypercholesterolemia has been proposed to influence cell functions via changes in membrane composition. The aim of the present study was to determine whether the membrane phospholipid composition of human lymphocytes is modified in hypercholesterolemia and whether these changes are accompanied by functional modifications. The phospholipid fatty acid contents and intracellular free calcium concentrations were determined in peripheral blood lymphocytes from 13 subjects with serum total cholesterol levels ranging from 4.6 to 8.8 mmol/l. The spontaneous basal rate of thymidine incorporation in lymphocyte of hypercholesterolemic individuals increased, while its relative stimulation by ConA was less effective. Important changes in membrane lipid composition, consisting mainly of decrease of the mass of phospholipids, and of associated polyunsaturated fatty acids were observed in hypercholesterolemia. In contrast, the cell cholesterol content was significantly increased. The intracellular free calcium concentration was enhanced and strongly associated with circulating cholesterol levels, cell cholesterol content and phospholipid fatty acids. These results indicate that hypercholesterolemia is accompanied by profound changes in lymphocyte membrane lipid composition and Ca(2+) handling.

Diminished soluble and total cellular L-selectin in cord blood is associated with its impaired shedding from activated neutrophils

We have previously shown that surface levels of the adhesive glycoprotein, L-selectin, are diminished on cord blood neutrophils (polymorphonuclear leukocytes, PMN) and associated with impaired adherence to endothelium under flow conditions. To test the hypothesis that diminished surface levels reflect a total cellular deficiency, we measured L-selectin in PMN lysates and plasma from cord and adult blood. L-selectin content was decreased in cord blood PMN lysates compared with those of adults by both Western blot analyses and ELISA (cord blood, 1195 +/- 160 pg/mL; adult, 1870 +/- 260 pg/mL; X +/- SEM; p < 0.05). Soluble L-selectin levels were also decreased in cord blood plasma (324 +/- 24 ng/mL versus 537 +/- 28 ng/mLiter in adult plasma, p < 0.01). To evaluate L-selectin function, we next compared the dose dependent effect of several chemoattractants on shedding of L-selectin from cord blood and adult PMN. Adult PMN showed greater overall shedding of L-selectin as compared with cord blood PMN after stimulation with fMet-Leu-Phe (p < 0.03) and granulocyte-macrophage colony-stimulating factor (p < 0.02). In contrast, shedding of L-selectin was similar between groups after IL-8 tested stimulation. We conclude that cord blood PMN have a decreased cellular content of L-selectin in addition to an impaired ability to shed surface L-selectin in response to specific inflammatory mediators.

Obesity and high-density lipoprotein cholesterol in black and white 9- and 10-year-old girls: The National Heart, Lung, and Blood Institute Growth and Health Study

It has been hypothesized that the role of obesity in the pathogenesis of coronary heart disease (CHD) may be mediated in part through its inverse relationship with high-density lipoprotein cholesterol (HDL-C). Obesity is inversely correlated with HDL-C, and HDL-C has been shown to be protective against CHD. Defining obesity as excess weight due to excess fat, the purpose of this analysis was to determine whether the effects of obesity are due to increased weight or to increased adiposity. Using baseline lipid and anthropometric data from the National Heart, Lung, and Blood Institute Growth and Health Study, cross-sectional associations among body mass, adiposity, HDL-C, and related lipid parameters (apolipoprotein [apo] AI and triglycerides [TGs]) were assessed in 821 white and 763 black 9- and 10-year-old girls, using multivariate linear regression models. Equations predicting HDL-C, apo AI, and TGs from age, race, race, sexual maturation stage, adiposity (sum of truncal--subscapular and suprailiac--skinfolds), and ponderosity (a ratio of weight to height) revealed that adiposity, not ponderosity, was the significant body composition variable to explain the variability of each of the lipids assessed. The amount of variance explained in each of the models was small (R2 <or= .10). When apo AI and TGs were added to the HDL-C model, R2 increased to 0.44 and race differences were no longer significant. These finding suggest that adiposity, not ponderosity, explains the effects of obesity on HDL-C, the effects are mediated through apo AI and TGs, and that black-white differences in HDL-C are a result of apo AI and TG-metabolic differences between the races.

Case report: Renal pseudotumours mimicking tumour recurrence after partial nephrectomy

Partial nephrectomy and tumour enucleation are increasingly accepted as an organ sparing approach for small renal cell carcinomas. Repeated computed tomography or sonography for the early detection of tumour recurrence are mandatory during the follow-up. We report two cases of renal pseudotumour mimicking a tumour recurrence: one case is related to the pseudotumoral appearance on sonography of a tumour defect filled by a fatty flap, and the other to the relative migration of an accessory spleen into the site of the cuneiform nephrectomy. The recognition of renal pseudotumours following partial nephrectomy prevents confusion with tumour recurrence on follow-up examinations.

Ca(2+)-binding domain VI of rat calpain is a homodimer in solution: hydrodynamic, crystallization and preliminary X-ray diffraction studies

The 21-kDa calcium-binding domain (VI) of the small subunit of rat calpain II has been expressed in Escherichia coli, purified, and crystallized. Two orthorhombic crystal forms have been obtained: space group P2(1)2(1)2(1) with a = 50.3, b = 56.5, c = 141.3 A; and space group C222(1) with a = 69.4, b = 73.9, c = 157.4 A. Diffraction data have been collected to 2.4 A. Sedimentation equilibrium, dynamic light scattering, and gel-permeation chromatography indicate that domain VI exists as a homodimer in solution. In accordance with the protein's behavior in solution, each crystal form contains two molecules per asymmetric unit. Screening for heavy-atom derivatives is in progress. To decrease the sensitivity to mercurials and to aid in the search for useful derivatives, Cys-to-Ser mutants have been prepared, expressed, and crystallized.

Expression of the adhesion molecules ICAM-1, VCAM-1, and E-selectin and their ligands VLA-4 and LFA-1 in chronic venous leg ulcers

BACKGROUND

Leukocyte binding to endothelial cells (ECs) is thought to contribute to the pathogenesis of leg ulcers caused by chronic venous insufficiency. In other systems, such binding is mediated by the interaction of adhesion molecules such as intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule- (VCAM-1) and E-selectin (on ECs), and leukocyte function-associated antigen-1(LFA-1) and very late activated antigen-4 (VLA-4) (on Leukocytes).

OBJECTIVE

Our purpose was to determine whether an increased expression of these adhesion molecules contributes to the pathogenesis of chronic venous insufficiency.

METHODS

Twenty-seven biopsy specimens of inflamed dermatoliposclerotic skin adjacent to venous leg ulcers were stained immunohistochemically with monoclonal antibodies against ICAM-1, VCAM-1, LFA-1, VLA-4, and E-selectin. Staining intensity was compared with that of normal skin.

RESULTS

Specimens of leg ulcers caused by chronic venous insufficiency showed increased expression of ICAM-1 and VCAM-1 but not of E-selectin on The expression of LFA-1 and VLA-4 on perivascular leukocytes was increased dramatically in comparison to healthy skin.

CONCLUSION

Upregulation of ICAM-1 and VCAM-1 on ECs may contribute to the increased adherence and extravasation of LFA-1 and VLA-4-positive leukocytes in chronic venous insufficiency.

The immunology of bullous oculo-muco-cutaneous disorders

In skin-blistering diseases, alteration of cellular adhesion results in a loss of cohesion of the epithelium of the skin and the mucous membranes. These disorders are often genetically determined and involve highly specific autoantibodies. A recent workshop discussed the immunology of these diseases.

Induction of tumor necrosis by delta-aminolevulinic acid and 1,10-phenanthroline photodynamic therapy

delta-Aminolevulinic acid (ALA) causes cells to accumulate protoporphyrin IX (Proto) and heme. Exposure to light in vitro causes intracellular Proto to initiate formation of singlet oxygen molecules, leading to self-destruction. This photoactivated destruction by ALA in vitro is enhanced by addition of the tetrapyrrole modulator 1,10-phenanthroline (Oph), which increases cellular accumulation of Proto. Here we significantly extend this idea by evaluating the efficacy of ALA and Oph photodynamic therapy of solid tumors in vivo. Methylcholanthrene-induced fibrosarcoma (Meth-A) cells were used, which lead to the formation of solid tumors when implanted into syngeneic recipients. Initially, suspensions of Meth-A cells were treated in vitro with combinations of ALA and Oph. Meth-A cells in suspension accumulated 6-fold greater amounts of Proto (P < 0.05) after 3-h incubation with ALA and Oph than when incubated with ALA alone, and were also more susceptible to subsequent photoactivated cell lysis in vitro. Similarly, solid Meth-A tumors grown in syngeneic BALB/c mice accumulated significant (P < 0.05) amounts of Proto 3 h after in vivo treatment with ALA, and Oph synergized with ALA to significantly (P < 0.05) enhance the induction of Proto in these tumors. ALA and Oph-based phototreatment of mice bearing Meth-A solid tumors resulted in necrosis of tumors, as determined by a significant reduction in both size and histopathology, with little damage to surrounding normal tissue. These data directly demonstrate the experimental usefulness of Proto modulators for ALA-based photodynamic therapy in the treatment of solid tumors in vivo and provide a rationale for their potential application in a multitude of tumor types.

Guidelines for the use of magnetic resonance techniques in monitoring the treatment of multiple sclerosis. US National MS Society Task Force

Because of the major difficulties in measuring clinical end points in multiple sclerosis (MS) treatment trials, there has been much enthusiasm for using magnetic resonance imaging (MRI) findings as an alternative outcome. To provide international consensus guidelines for the use of MRI in MS clinical trials, a task force of the US National MS Society was convened. The recommendations of the task force are presented in this review. Given the high sensitivity for detecting pathological activity in relapsing-remitting and secondary progressive MS, monthly T2-weighted and gadolinium-enhanced brain MRI is an excellent tool for short-term exploratory trials of new agents where it serves as the primary end point; in particular, failure to demonstrate a reduction in lesion activity avoids the time, cost, and risks of a larger clinical end point study. However, conventional MRI findings have a limited correlation with disability in established MS. The primary end point of a definitive trial should therefore be clinical, although serial MRI at 6- to 12-month intervals is a useful secondary end point in providing an index of pathological progression. In trials of patients presenting with clinically isolated syndromes suggestive of MS, MRI findings can be used in the entry criteria, and as a secondary outcome measure, but conversion to clinically definite MS should be the primary outcome. The pathological substrates of irreversible disability are demyelination and axonal loss. Putative magnetic resonance markers for these processes include decreased N-acetylaspartate on proton magnetic resonance spectroscopy, decreased magnetization transfer ratios, hypointensity on T1-weighted images, and loss of short T2 water fractions, some of which relate more closely to disability than conventional MRI findings. Further technical developments should lead to more accurate quantitation, greater pathological specificity, and stronger clinical correlations.