Intraesophageal balloon distension test in Chagas' disease patients with noncardiac chest pain

Patients with Chagas' disease often have chest pain as a prominent symptom. The objective of this study was to compare the results of intraesophageal balloon distension in chagasic and nonchagasic patients with chest pain not caused by coronary obstruction. We studied 40 patients with chest pain and angiographically normal coronary arteries, 25 with a positive serologic test for Chagas' disease (Chagas group, 16 women, mean age 53+/-10 years), and 15 with a negative serologic test (control group, 11 women, mean age 46+/-10 years). All patients had radiologic and endoscopic examinations of esophagus, stomach, and duodenum, esophageal manometry with the acid infusion test in the distal esophagus, and intraesophageal balloon distension. None of them had esophageal dilation or any signs of cardiovascular disease. A 25-mm-long latex balloon located 10 cm above the lower esophageal sphincter was inflated and deflated over a period of 10 sec at 1-ml increments of air until the subjects reported chest pain or to a maximum volume of 20 mi. The test caused chest pain in 14 subjects in the control group (93%) and in 12 in the Chagas' disease group (48%, P < 0.05). The mean volume of air that caused chest pain was 10+/-3 ml in the control group and 15+/-4 ml in the Chagas' disease group (mean+/-SD, P < 0.05). The maximum intraesophageal pressure during the examination was higher in Chagas' disease patients with chest pain during balloon distension (60 +/- 21 mm Hg) than in patients who did not have chest pain (37 +/-18 mm Hg, P < 0.05) and did not differ from the control group (48+/-16 mm Hg, P > 0.05). With the other examinations there was no difference between groups or between patients with or without chest pain during the balloon distension test. Although esophagitis was observed in 47% of patients in the control group and in 40% of the Chagas' disease group, the acid infusion test was positive in 27% of patients in the control group and in 4% of patients in the Chagas' disease group. We conclude that, as compared to a group of patients with similar chest pain, chagasic patients are less sensitive to esophageal distension. Thus, it is unlikely that their chest pain is related to esophageal mechanisms.     

A GTPase-independent mechanism of p21-activated kinase activation. Regulation by sphingosine and other biologically active lipids

p21-activated kinases (PAKs) are serine/threonine kinases that have been identified as targets for the small GTPases Rac and Cdc42. PAKs have been implicated in cytoskeletal regulation, stimulation of mitogen-activated protein kinase cascades, and in control of the phagocyte NADPH oxidase. Membrane targeting of PAK1 induced increased kinase activity in a GTPase-independent manner, suggesting that other mechanisms for PAK regulation exist. We observed concentration- and time-dependent activation of PAK1 by sphingosine and several related long chain sphingoid bases but not by ceramides or a variety of other lipids. Although phospholipids were generally ineffective, phosphatidic acid and phosphatidylinositol also had stimulatory effects on PAK1. Lipid stimulation induced a similar level of PAK1 activity as did stimulation by GTPases, and the patterns of PAK1 autophosphorylation determined after partial tryptic digestion and two-dimensional peptide analysis were similar with each class of activator. Lipid stimulation of PAK1 activity was dependent upon intact PAK kinase activity, as indicated by studies with a kinase-dead PAK1 mutant. Treatment of COS-7 cells expressing wild type PAK1 with sphingosine, fumonisin B, or sphingomyelinase, all of which are able to elevate the levels of free sphingosine, induced increased activity of PAK1 as determined using a p47(phox) peptide substrate. Studies using PAK1 mutants suggest that lipids act at a site overlapping or identical to the GTPase-binding domain on PAK. The inactive sphingosine derivative N,N-dimethylsphingosine was an effective inhibitor of PAK1 activation in response to either sphingosine or Cdc42. Our results demonstrate a novel GTPase-independent mechanism of PAK activation and, additionally, suggest that PAK(s) may be important mediators of the biological effects of sphingolipids.     

The role of CD8+ CD40L+ T cells in the formation of germinal centers in rheumatoid synovitis

In rheumatoid synovitis, lymphocytes can be arranged in follicular structures resembling secondary lymphoid follicles. To understand the organizing principles of this ectopic lymphoid tissue, the cellular components contributing to synovial follicles were examined. In 9 of 24 synovial tissue biopsies, lymphoid aggregates were found consisting of CD4+ T cells and CD20+ B cells. In four of the nine patients, the follicular centers were occupied by CD23+ CD21+ cellular networks representing follicular dendritic cells involved in germinal center reactions. In five patients, CD23+ cells were absent from the centers of the aggregates, suggesting that fully developed germinal centers are generated in only a subset of patients. To identify factors involved in the regulation of the synovial microarchitecture, cell populations contributing to the follicles were quantified by digital image analysis of immunostained tissue and by flow cytometry of tissue-derived lymphocytes. Proportions of CD4+, CD20+, and CD68+ cell subsets were surprisingly invariant, irrespective of the presence or absence of CD23+ follicular dendritic cells. Instead, tissue biopsies with CD23+ germinal center-like regions could be distinguished from those with CD23- T cell-B cell aggregates by a fourfold increase in the frequency of tissue-infiltrating CD8+ T cells, a fraction of which expressed CD40 ligand (CD40L). The data suggest a previously unsuspected role of CD8+ lymphocytes in modulating germinal center formation and raise the possibility that CD8+ CD40L+ T cells are involved in aggravating pathologic immune responses in rheumatoid synovitis.     

Consumption of fatty fish from the Baltic Sea and PCB in whole venous blood, plasma and cord blood from delivering women in the Aland/Turku archipelago

The present study aimed to assess the role of fish consumption for the body burden of polychlorinated biphenyls (PCBs) in mothers living in the Aland and Turku archipelago in Finland. The overall objective was to investigate whether there exists an appropriate population for a full-scale prospective study on PCB-related developmental effects in infants. Concentrations of the four major PCBs were determined in whole venous blood and cord blood from 30 delivering mothers, of which 20 subjects consumed fatty fish from the Baltic Sea (2.5-12.5 meals per month) and the remaining 10 mothers did not. The concentrations of CB-118, CB-138, CB-153, and CB-180 in cord blood were generally two- to threefold lower than in whole blood from the mothers, but strong correlations were observed between PCBs in the two matrices (r = .67-.80). Neither the venous blood nor cord blood concentrations of PCBs, however, were correlated with stated fish intake. Moreover, the concentration of CB-153 in plasma was only weakly associated with fish intake, and the level of organic mercury in erythrocytes was not correlated with fish intake at all. The present results of CB-153 concentrations in women's blood are lower than those reported in other recent investigations. A reasonable contributing explanation is the rapid decline during the last decades of PCB in Baltic Sea fish, which has resulted in less impact of fish intake on the body burdens of PCB in relatively young women (median 30 yr in the present study) as compared with older females. The relatively low PCB levels in blood taken together with the low number of yearly deliveries in the archipelago population makes it an inappropriate study base for a prospective study of PCB-related health effects in infants.     

The smallest known eukaryotic genomes encode a protein gene: towards an understanding of nucleomorph functions

Cryptomonads are unicellular algae with plastids surrounded by four membranes. Between the two pairs of membranes lies a periplastidal compartment that harbours a DNA-containing organelle, termed the nucleomorph. The nucleomorph is the vestigial nucleus of a phototrophic, eukaryotic endosymbiont. Subcloning of parts of one nucleomorph chromosome revealed a gene coding for an Hsp70 protein. We demonstrate the expression of this nucleomorph protein-coding gene and present a model for protein transport from the host to the endosymbiont compartment.     

Paternal origin of trisomy 21 following intracytoplasmic sperm injection (ICSI)

One important aspect in the debate on the genetic risks associated with intracytoplasmic sperm injection (ICSI) is the possible increased rate of chromosomal abnormalities in resulting pregnancies. ICSI was performed in a 27 year old man with asthenoteratozoospermia and his 25 year old wife. There was a spontaneous miscarriage at 9 weeks of gestation. Cytogenetic investigation revealed trisomy 21. Analysis of two polymorphic microsatellite markers showed that the additional chromosome was paternal. This is in contrast to the fact that the vast majority of trisomic concepti are maternal in origin. Identifying the parent of origin in trisomic conceptions achieved by ICSI may reveal whether ICSI is associated with an increased risk of paternally derived aneuploidy.     

Estimating the costs of hip fracture and potential savings

Shaker mutant rats are characterized by the adult-onset degeneration of cerebellar anterior lobe Purkinje cells and temporally correlated development of ataxia and tremor. Normal E-13 Purkinje cells were transplanted into the anterior cerebellum in adult shaker mutant rats to study donor/host interactions in an animal with adult-onset heredodegeneration. Donor Purkinje cells from extraparenchymal transplant sites migrated radially into the host molecular layer and differentiated. Donor Purkinje cell dendrites expanded to fill the host molecular layer, spinous processes were apparent, and axonal projections into the host gray and white matter were observed. Donor Purkinje cells remaining in the extraparenchymal transplant sites differentiated if they were located relatively close to the host cerebellum. Donor Purkinje cells located intraparenchymally in the host white matter or granule cell layer survived, but were stunted in their development. The orthogonal movement of donor Purkinje cells away from transplant sites in the host cerebellum was spatially restricted. The findings from this study indicate that host cerebellar cortex with adult-onset heredodegeneration of Purkinje cells supports the survival and differentiation of transplanted normal embryonic Purkinje cells.