Role of cytokines in progression of endometriosis

Peritoneal fluid in women with endometriosis contains an increased number of activated macrophages that secrete a variety of cytokines, including interleukin (IL)-6, IL-8, vascular endothelial growth factor, and tumor necrosis factor-alpha (TNF-alpha). Cytokines may be involved in the control of implantation and the growth of endometrial cells outside the uterus. In addition, several cytokines have been implicated in or directly associated with angiogenic activity in endometriosis. There could be a relationship between the levels of cytokines in the peritoneal fluid of patients with endometriosis and the status of the lesions in such patients. Peritoneal endometriosis can be classified as having red, black, or white lesions. Red lesions are known to be an active form of early endometriosis, because vascularization and mitotic activity are shown to be most prominent in these lesions. We found that the peritoneal fluid levels of TNF-alpha and IL-8 were significantly higher in patients with endometriosis, and correlated with the size and number of active lesions. In addition, TNF-alpha and IL-8 stimulated the growth of ectopic endometrial stromal cells. These cytokines with angiogenic activity may therefore have significant roles in the pathogenesis of endometriosis.

Effect of a thromboxane A(2) antagonist on sputum production and its physicochemical properties in patients with mild to moderate asthma

STUDY OBJECTIVE

To determine the effects of a specific thromboxane A(2) (TxA(2)) receptor antagonist, seratrodast, on asthma control and airway secretions.

DESIGN

Multicenter, double-blind, randomized, placebo-controlled study.

PATIENTS

Forty-five patients with mild to moderate asthma who had been continuously expectorating sputum of > 20 g/d. Patients with a current pulmonary infection or taking oral corticosteroids, antibiotics, or mucolytic agents were excluded from the trial.

INTERVENTIONS

Following a 2-week run-in period, while pulmonary function, sputum production, and mucociliary function were assessed, patients were assigned to receive seratrodast, 40 mg/d, or placebo for 6 weeks.

MEASUREMENTS AND RESULTS

During the treatment period, the changes in FEV(1) and peak expiratory flow (PEF) were not different between the two patient groups, but there were significant reductions in diurnal variation of PEF (p = 0.034), frequency of daytime asthma symptoms (p = 0.030), and daytime supplemental use of beta(2)-agonist (p = 0.032) in the seratrodast group. For sputum analysis, seratrodast treatment decreased the amount of sputum (p = 0.005), dynamic viscosity (p = 0. 007), and albumin concentration (p = 0.028), whereas it had no effect on elastic modulus or fucose concentration. Nasal clearance time of a saccharin particle was shortened in the seratrodast group at week 4 (p = 0.031) and week 6 (p = 0.025), compared with the placebo group.

CONCLUSION

Blockade of TxA(2) receptor has minimal effects on pulmonary function, but may cause an improvement in mucociliary clearance by decreasing the viscosity of airway secretions.

Adenosine A3 receptor-mediated airway microvascular leakage: role of mast cells and tachykinins

To determine whether adenosine A3 receptor stimulation produces airway inflammation and, if so, what the mechanism of action is, we studied microvascular permeability in the rat trachea. After intravenous injection of Evans blue dye, adenosine and various adenosine analogues were given by inhalation, and the tracheal microvascular permeability was determined by a photometric measurement of extravasated dye. N6-2-(4-aminophenyl)-ethyladenosine (APNEA), an adenosine A3 receptor agonist, dose dependently increased plasma protein extravasation, whereas adenosine, the A1-receptor agonist N6-(R-phenylisopropyl)-adenosine, or the A2-receptor agonist 5'-N-ethyl-carboxamidoadenosine had no effect. The effect of APNEA was not altered by the adenosine A1/A2 receptor antagonist 8-(p-sulphophenyl)-theophylline, but was reduced by depletion of mast cell-derived mediators with compound 48/80 or pretreatment with the tachykinin NK1 receptor antagonist CP99,994. These results suggest that activation of A3 receptor specifically increase airway microvascular permeability probably via mast cell-derived mediators and tachykinins.

DE1, a 12-base pair cis-regulatory element sufficient to confer dark-inducible and light down-regulated expression to a minimal promoter in pea

We found a cis-regulatory element of 12 base pairs (bp) (GGATTTTACAGT) capable of conferring light responsiveness to a minimal promoter, CaMV 35S46, in pea. The 12-bp sequence is located in the 5' upstream region of the light down-regulated gene pra2, which encodes a small GTPase belonging to the YPT/rab family. Here we examined gain-of-function analyses using synthetic promoter-luciferase constructs in a transient assay and found that the 12-bp element alone was sufficient to confer dark induction, as well as light down-regulation on the minimal promoter. We named this dark inducible element DE1. Effects of various light conditions on the reporter gene activity showed that DE1 received signals from phytochrome A, phytochrome B, and blue light photoreceptors. Using phytochrome-deficient mutants, we showed that the pra2 protein level in seedlings was also regulated by these photoreceptors. The changes in the immunoblotting pattern of the pra2 protein in these mutants were correlated with the changes in epicotyl elongation. Results from transient assays using these mutants showed that the DE1 received signals from phytochromes A and B, demonstrating that this element is indeed a light-responsive element. To our knowledge, this is the first cis-element that by itself confers light responsiveness to a minimal promoter.

[Presacral malignant peripheral nerve sheath tumor in a patient with von Recklinghausen disease: case report]

A 32-year-old woman was admitted to our institution with dysuria and pain in the left foot. She was diagnosed with von Recklinghausen disease based on the physical findings, and an elastic, firm mass was palpable with the fingertip on the posterior wall of the rectum. Ultrasonography, computed tomography, and magnetic resonance imaging revealed a solid tumor, which measured 8 cm in diameter, in the presacral space. The tumor was diagnosed as a presacral solid tumor and the tumor was extirpated. The specimen was a 10 x 8 x 8 cm yellowish solid tumor weighing 250 g. The histopathologic diagnosis was malignant peripheral nerve sheath tumor (MPNST). Presacral MPNST is rarely diagnosed in the early stage, and the prognosis for MPNST patients with von Recklinghausen disease is relatively poor. Tumor resection with wide surgical margins is necessary and close follow-up after surgery is mandatory.

CX3C-chemokine, fractalkine-enhanced adhesion of THP-1 cells to endothelial cells through integrin-dependent and -independent mechanisms

Leukocyte adhesion and trafficking at the endothelium requires both cellular adhesion molecules and chemotactic factors. A newly identified CX3C chemokine, fractalkine, expressed on activated endothelial cells, plays an important role in leukocyte adhesion and migration. We examined the functional effects of fractalkine on beta1 and beta2 integrin-mediated adhesion using a macrophage-like cell line, THP-1 cells. In this study, we report that THP-1 cells express mRNA encoding a receptor for fractalkine, CX3CR1, determined by Northern blotting. Scatchard analysis using fractalkine-SEAP (secreted form of placental alkaline phosphatase) chimeric proteins revealed that THP-1 cells express a single class of CX3CR1 with a dissociation constant of 30 pM and a mean expression of 440 sites per cell. THP-1 cells efficiently adhered, in a fractalkine-dependent manner, to full-length of fractalkine immobilized onto plastic and to the membrane-bound form of fractalkine expressed on ECV304 cells or TNF-alpha-activated HUVECs. Moreover, soluble-fractalkine enhanced adhesion of THP-1 cells to fibronectin and ICAM-1 in a dose-dependent manner. Pertussis toxin, an inhibitor of Gi, inhibited the fractalkine-mediated enhancement of THP-1 cell adhesion to fibronectin and ICAM-1. Finally, we found that soluble-fractalkine also enhanced adhesion of freshly separated monocytes to fibronectin and ICAM-1. These results indicate that fractalkine may induce firm adhesion between monocytes and endothelial cells not only through an intrinsic adhesion function itself, but also through activation of integrin avidity for their ligands.

Expression of prostaglandin E synthase mRNA is induced in beta-amyloid treated rat astrocytes

Deposition of beta-amyloid (A beta) in the brain is considered to be one of the most critical events in the onset of Alzheimer's disease (AD). In order to identify factors involved in the exacerbation of AD, we investigated transcriptionally A beta-induced genes using a cDNA subtraction technique in rat astrocytes. One gene obtained was rat prostaglandin (PG) E synthase. In this report, we present the deduced sequence for rat PGE synthase for the first time and demonstrate the induction of PGE synthase mRNA by treatment of cells with A beta. Our results suggest a possibly significant role of this enzyme in the progression of AD.

Recombinant carboxyltransferase responsive to redox of pea plastidic acetyl-CoA carboxylase

Acetyl-CoA carboxylase regulates the rate of fatty acid synthesis. This enzyme in plants is localized in plastids and is believed to be composed of biotin carboxyl carrier protein, biotin carboxylase, and carboxyltransferase made up of alpha and beta polypeptides, although the enzyme has not been purified yet. Accumulated evidence shows that pea plastidic acetyl-CoA carboxylase is activated by light and the activation is caused by light-dependent reduction of carboxyltransferase, but not of biotin carboxylase, via a redox cascade. To understand the reductive activation of carboxyltransferase at the molecular level here, we obtained the active enzyme composed of decahistidine-tagged (His tag) alpha and beta polypeptides through the expression of the pea plastidic carboxyltransferase gene in Escherichia coli. Gel filtration showed that the molecular size of the recombinant carboxyltransferase is in agreement with that of partially purified carboxyltransferase from pea chloroplasts. The catalytic activity of the recombinant enzyme was similar to that of native carboxyltransferase. These results indicate that the molecular structure and conformation of recombinant carboxyltransferase resemble those of its native counterpart and that native carboxyltransferase is indeed composed of alpha and beta polypeptides. This recombinant enzyme was activated by dithiothreitol, a known reductant of S-S bonds, with a profile similar to that of its native counterpart. The recombinant enzyme was activated by reduced thioredoxin-f, a signal transducer of redox potential in chloroplasts under irradiation. Thus, this enzyme was redox-regulated, like that of the native carboxyltransferase.

Tumor necrosis factor-alpha promotes proliferation of endometriotic stromal cells by inducing interleukin-8 gene and protein expression

Endometriosis, a common disease among women of reproductive age, is characterized by the presence of endometrial-like tissue outside the uterus. We and others showed that several cytokine levels, including interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNFalpha), are elevated in the peritoneal fluid of women with endometriosis compared with those in women without endometriosis. We also demonstrated that the addition of IL-8 to the culture medium stimulated the proliferation of cultured endometriotic stromal cells. TNFalpha is a multipotent cytokine that induces IL-8 production in various cell types. Therefore, we hypothesized that TNFalpha may also contribute to the pathogenesis of endometriosis by inducing the production of IL-8. To test this hypothesis, we analyzed the peritoneal fluid concentrations of IL-8 and TNFalpha using enzyme-linked immunosorbent assay (ELISA). We observed a significant correlation between the levels of TNFalpha and IL-8 in the peritoneal fluid of endometriosis patients. We also obtained the endometriotic stromal cells from chocolate cyst linings of the ovary. The expression of the receptors for TNFalpha (TNFR) was examined by RT-PCR. We observed the expression of both TNFR-I and TNFR-II genes in endometriotic stromal cells. The expression of IL-8 gene and protein was analyzed by Northern blot hybridization and enzyme-linked immunosorbent assay, respectively. TNFalpha induced the gene and protein expression of IL-8 in endometriotic stromal cells in a dose-dependent fashion. The addition of TNFalpha promoted the proliferation of the endometriotic stromal cells, and the stimulatory effects of TNFalpha were abolished by adding anti-IL-8 antibody. We demonstrated for the first time that TNFalpha stimulated proliferation of endometriotic stromal cells through induction of IL-8 gene and protein expression. We concluded that the TNFalpha may be one of the essential factors for the pathogenesis of endometriosis.

Altered gene expression and secretion of interleukin-6 in stromal cells derived from endometriotic tissues

OBJECTIVE

To compare the expression of interleukin-6 (IL-6) in endometrial and endometriotic cells.

DESIGN

Prospective study.

SETTING

Department of Obstetrics and Gynecology, Tottori University Hospital, Yonago, Japan.

PATIENT(S)

Twenty patients who underwent either hysterectomy or laparoscopic surgery.

INTERVENTION(S)

Endometrial and endometriotic stromal cells were obtained from normal endometrium and from chocolate cyst linings of the ovary. Peritoneal macrophages were isolated from peritoneal fluids. Cells were cultured in the presence or absence of tumor necrosis factor-alpha.

MAIN OUTCOME MEASURE(S)

Gene expression of IL-6 was examined by Northern blot analysis. Interleukin-6 protein production was examined by immunocytochemical staining and ELISA.

RESULT(S)

A single IL-6 messenger RNA band of approximately 1.3 kilobases was detected in endometriotic stromal cells. Tumor necrosis factor-alpha increased the expression of IL-6 messenger RNA in endometriotic cells in a dose-dependent manner. In endometrial stromal cells, IL-6 messenger RNA signals were much weaker. Endometriotic stromal cells produced significantly larger amounts of IL-6 compared with endometrial stromal cells under basal conditions and after stimulation with tumor necrosis factor-alpha. Interleukin-6 protein was detected in cells isolated from endometriotic tissues by immunocytochemical staining. Interleukin-6 production by cultured macrophages from patients with endometriosis and endometriotic stromal cells was comparable.

CONCLUSION(S)

Altered gene expression and protein secretion of IL-6 in patients with endometriosis may contribute to the pathogenesis of the disease and/or to endometriosis-associated infertility.

[Endothelial injury by oxidized LDL]

Recent progress in the research of oxidized LDL has revealed that this lipoprotein causes not only foam cell transformation of macrophages but also several endothelial dysfunction, and the effects on endothelial cells are also involved with the process of atherogenesis. Receptors for oxidized LDL on endothelial cells, such as LOX-1 and SREC, have been cloned and their characteristics are now under investigation. In addition to lowering plasma cholesterol level, it is expected that new strategies to prevent atherosclerosis is established by focusing on the endothelial injury caused by oxidized LDL.

Moyamoya disease presenting as cerebral infarction after cesarean

BACKGROUND

Moyamoya disease with pregnancy is rare and might present with cerebral hemorrhage.

CASE

A 22-year-old primigravida suddenly developed muscular weakness in the right arm and facial discomfort 3 days after cesarean. Computed tomography and cerebrovascular angiography found cerebral infarction attributable to moyamoya disease. Bilateral anastomosis of superficial temporal and middle cerebral arteries was done.

CONCLUSION

Moyamoya disease with pregnancy might present as cerebral infarction after cesarean.

In vivo therapeutic effects of IFN-gamma on human myelogenous leukemia in a severe combined immunodeficiency mouse model

BACKGROUND

Results of clinical trials of IFN-gamma on the treatment of various types of leukemia are not so promising, regardless of the antiproliferative activity against leukemic cells and expected immunomodulatory effects. In this study, we have re-evaluated the anti-leukemic effects of natural human IFN-gamma (nHuIFN-gamma) using an established human myelogenous leukemia model in SCID mice.

MATERIALS AND METHODS

SCID mice transplanted with human myelogenous leukemia cell line ML-2S received subcutaneously 5 x 10(4) IU/mouse of nHuIFN-gamma at 5 times/week for 5 weeks.

RESULT

nHuIFN-gamma significantly prolonged the lifespan of SCID mice in leukemic crisis. Percentages of ML-2S cells in the peripheral blood were also significantly decreased by the IFN-gamma treatment. Histopathological examination revealed that IFN-gamma treatment suppressed the replacement of pancreatic cells by tumor cells and the formation of tumor masses in the intestine.

CONCLUSIONS

These results suggest that IFN-gamma is effective against human myeloid leukemia, especially extramedullary tumor mass-forming type in the peritoneal organs. Our results further suggest that studies employing SCID mice leukemia model would help in devising appropriate therapeutic strategies of IFN-gamma based on the specific characteristics of each leukemia subtype.

Effect of cromolyn on adenosine-induced airway microvascular leakage in sensitized rats

Inhalation of adenosine causes bronchoconstriction in asthmatic subjects, but the effect of this purine nucleotide on airway vascular permeability is unknown. In order to determine whether adenosine produces airway microvascular leakage and, if so, to examine the effect of cromolyn (sodium cromoglycate (SCG)) on this extravasation of Evans blue was measured in the airways of ovalbumin-sensitized Brown Norway rats. Inhaled adenosine caused microvascular leakage in sensitized but not in non-sensitized rats, and the response was abolished by capsaicin pretreatment or the tachykinin neurokinin-1 receptor antagonist FK888. Adenosine-induced vascular leakage became apparent in nonsensitized rats when treated with phosphoramidon, and airway neutral endopeptidase activity was lower in sensitized than in non-sensitized animals. The extravasation induced by adenosine in sensitized rats was dose dependently inhibited by SCG aerosols, SCG likewise inhibited microvascular responses to substance P, but had no effect on those to platelet-activating factor. These results suggest that: 1) adenosine induces airway microvascular leakage in sensitized rats through stimulation of neurokinin-1 receptors; 2) this effect is associated with a sensitization-induced decrease in neutral endopeptidase activity; and 3) sodium cromoglycate inhibits adenosine-induced extravasation, presumably via functional antagonism of tachykinins.

Role of the oxygen uptake efficiency slope in evaluating exercise tolerance

OBJECTIVE

To investigate the interprotocol agreement of oxygen uptake efficiency slope (OUES).

METHODS

16 Japanese children and adolescents (10 boys and six girls) underwent two sessions of maximal exercise testing according to the following two treadmill protocols: the standard Bruce protocol and the rapidly increasing staged (RIS) protocol. Maximal oxygen uptake (VO2max), the ventilatory anaerobic threshold (VAT), and the OUES were obtained from the gas analysis data. Agreement between the protocols was tested by means of the Bland-Altman method.

RESULTS

Interprotocol agreement was excellent for the OUES (limit of agreement, -18% to 17% of the mean value), slightly less good for VO2max (limit of agreement, -20% to 24% of the mean value), and poor for the VAT (limit of agreement, -31% to 31% of the mean value).

CONCLUSION

These results confirm the clinical usefulness of the OUES as a measure of evaluating exercise tolerance in the paediatric population.

Identification of a cis-regulatory element involved in phytochrome down-regulated expression of the pea small GTPase gene pra2

The pra2 gene encodes a pea (Pisum sativum) small GTPase belonging to the YPT/rab family, and its expression is down-regulated by light, mediated by phytochrome. We have isolated and characterized a genomic clone of this gene and constructed a fusion DNA of its 5'-upstream region in front of the gene for firefly luciferase. Using this construct in a transient assay, we determined a pra2 cis-regulatory region sufficient to direct the light down-regulation of the luciferase reporter gene. Both 5'- and internal deletion analyses revealed that the 93-bp sequence between -734 and -642 from the transcriptional start site was important for phytochrome down-regulation. Gain-of-function analysis showed that this 93-bp region could confer light down-regulation when fused to the cauliflower mosaic virus 35S promoter. Furthermore, linker-scanning analysis showed that a 12-bp sequence within the 93-bp region mediated phytochrome down-regulation. Gel-retardation analysis showed the presence of a nuclear factor that was specifically bound to the 12-bp sequence in vitro. These results indicate that this element is a cis-regulatory element involved in phytochrome down-regulated expression.

Menstrual cycle-specific inhibition of the proliferation of endometrial stromal cells by interleukin 6 and its soluble receptor

OBJECTIVE

This study investigated the possible roles of interleukin 6 and soluble interleukin 6 receptor in the growth of endometrial and endometriotic cells.

STUDY DESIGN

Endometrial and endometriotic stromal cells were collected from the uterus or from ovarian chocolate cysts. We examined the effects of interleukin 6, soluble interleukin 6 receptor, and a combination of both factors on the proliferation of endometrial and endometriotic stromal cells. The action of sex steroids on the interleukin 6 regulation of the growth of stromal cells was also evaluated. The gene expressions of interleukin 6 receptor and glycoprotein 130 were examined in endometrial and endometriotic cells by reverse transcription-polymerase chain reaction.

RESULTS

Interleukin 6 had no effect on the growth of stromal cells in tissue from the proliferative phase. In contrast, the addition of concentrations of >/=100 pg/mL interleukin 6 induced significant inhibition of stromal cell proliferation in tissue from the secretory phase. Similarly, the addition of soluble interleukin 6 receptor caused significant suppression in the growth of endometrial stromal cells in tissue from the secretory phase but not the proliferative phase. On the other hand, stromal cells of endometriotic tissues were resistant to interleukin 6, showing no inhibitory response. Although the combination treatment did not affect the proliferation of stromal cells of the proliferative phase and of endometriotic tissues, 10 pg/mL interleukin 6 inhibited proliferation of stromal cells of the secretory phase in the presence of 1 ng/mL soluble interleukin 6 receptor. Treatment with estradiol and progesterone for 10 days newly induced the inhibitory response to interleukin 6 in the endometrial cells from the proliferative phase. Expressions of transcripts of interleukin 6 receptor and glycoprotein 130 were observed in the endometrial cells from the proliferative and secretory phases and in endometriotic cells.

CONCLUSIONS

Interleukin 6 may play a central role in regulation of the growth of endometrial cells as a mediator of endocrine action. Endometriotic cells may behave differently from their normal counterparts in terms of the inhibitory regulation exerted by interleukin 6.

Overexpression of salt-tolerant glutaminase from Micrococcus luteus K-3 in Escherichia coli and its purification

A high-expression plasmid, pKSGHE3-1, containing the salt-tolerant glutaminase (EC 3.5.1.2) from marine bacterium Micrococcus luteus K-3 was constructed. pKSGHE3-1 was made by inserting the DNA fragment (1.43 kb) containing the structural gene synthesized by polymerase chain reaction into the downstream region of the tac promoter of expression vector pKK223-3. The translational start codon was located 10 bases downstream of the Shine-Dalgarno sequence (AGGA) of pKK223-3. Escherichia coli JM109 transformed with pKSGHE3-1 exhibited more than 190-fold higher glutaminase activity than M. luteus K-3 under optimal culture conditions. The enzyme was purified to homogeneity through three column chromatography steps with a final yield of 17.1%. The recombinant enzyme showed the same enzymatic properties, including salt tolerance, as those of M. luteus K-3. This glutaminase expression system allows the production of sufficient quantities of glutaminase for basic structure-function studies including chemical modification and future X-ray crystallization analysis.

Establishment of an in vivo human myeloid leukemia model in the SCID mouse

We succeeded in establishing a human myelogenous leukemia model in severe combined immunodeficient (SCID) mice by transplanting 2 x 10(7) ML-2 cells intraperitoneally (i.p.) with cyclophosphamide (CTX) pretreatment. Two months after transplantation, 9 of 10 mice developed leukemia and leukemia cells were detected in the peripheral blood (PB) and bone marrow (BM). The main findings at autopsy were peritoneal and pleural effusions and large tumor masses involving the peritoneal organs. However, successful transplantation required injection of a large number of cells. We therefore established a new cell line, ML-2S, from the PB of a mouse with ML-2 leukemia. Although only 2 x 10(6) ML-2S cells were inoculated, ML-2S induced the same pattern of leukemic dissemination reminiscent of the parent ML-2 cells. Compared to ML-2, progression of ML-2S was slow, suggesting that ML-2S is suitable as a leukemia model to study treatment. Furthermore, we confirmed that ML-2S cells are of human origin using isoenzyme analysis and also that ML-2S and ML-2 cells have the same phenotypic character by cell surface marker analysis.

Structure and activation of the large latent transforming growth factor-Beta complex

BACKGROUND

Many cytokines regulate processes involved in the pathogenesis of proliferative vitreoretinopathy. Transforming growth factor-beta (TGF-beta) is an example of a pluripotent growth factor that regulates cell proliferation, extracellular matrix (ECM) deposition, cell migration, and differentiation--all biological activities involved in the formation and progression of proliferative vitreoretinopathies.

METHODS

A review of experimental results that demonstrate how vascular cells generate biologically active TGF-beta is presented. Most cell types--including endothelial cells and pericytes, which form the retinal microvasculature--express TGF-beta as a large latent TGF-beta complex. Mature TGF-beta, the biologically active form, must be generated from the large latent complex before it can signal by binding to its high affinity cell surface receptors.

RESULTS

A critical step in regulating TGF-beta effects may be the activation of the large latent TGF-beta complex. Activation of the complex can be achieved by chemical and enzymatic treatments, or by various cell systems. We have identified that co-culturing bovine smooth muscle cells or pericytes and endothelial cells generates active TGF-beta.

CONCLUSION

The mechanism of latent TGF-beta activation self-regulates through effectors of plasmin generation. Studying TGF-beta generation by co-cultures of pericytes and endothelial cells can provide us with insights into how disruption of latent TGF-beta activation may lead to unregulated endothelial proliferation, ECM deposition, and cellular infiltration, as observed clinically in neovascular- and fibrotic-related pathologies.

Co-stimulation of T cells with CD2 augments TCR-CD3-mediated activation of protein tyrosine kinase p72syk, resulting in increased tyrosine phosphorylation of adapter proteins, Shc and Cbl

Complete T cell activation requires not only the first signal via TCR-CD3 engagement, but also a co-stimulatory signal through accessory receptors such as CD2, LFA-1 and CD28. However, the pathway of co-stimulatory signaling through accessory receptors is incompletely understood. We report here that CD2 provides a co-stimulus for activation of CD3-mediated syk/ZAP-70 family kinase, p72Syk (Syk), in Jurkat T cells. Although cross-linking of CD2 alone or any combination of CD2 with LFA-1alpha, LFA-1beta or CD28 did not induce tyrosine phosphorylation of Syk, co-cross-linking of CD2 with CD3 enhanced CD3-mediated tyrosine phosphorylation of Syk. Enhancement of tyrosine phosphorylation of Syk by CD2 co-stimulation was CD2 antibody concentration-dependent, and time course studies showed that CD2 co-stimulation enhanced Syk tyrosine phosphorylation by 30 s and through 5 min stimulation compared with the control. In vitro kinase assay revealed that co-cross-linking of CD2 with CD3 augmented Syk kinase activity using myelin basic protein as a substrate. Furthermore, CD2 co-stimulation with CD3 resulted in enhanced tyrosine phosphorylation of adapter proteins, such as Shc and Cbl, in an antibody concentration-dependent manner. Finally, CD2 provided a co-stimulatory signals for synthesis of IL-2 in Jurkat cells and phytohemagglutinin (PHA)-activated T cells and for proliferation of PHA-activated T cells. Taken together, these results indicate that CD2 is an important co-stimulatory receptor for CD3-mediated T cell activation and functions in concert with CD3.

Ventilatory control during exercise in normal children

We investigated the relation between age and respiratory control during exercise in 80 children aged 6.4-17.6 y (42 male, age, 11.6 +/- 3.3 y; body weight, 41.3 +/- 14.7 kg; and 38 female, age, 12.6 +/- 2.7 y; body weight, 42.5 +/- 9.3 kg). Exercise tests were performed on a treadmill after a standard symptom-limited Bruce protocol. Data were analyzed separately for boys and girls. At rest and at peak exercise, the ratio of minute ventilation to carbon dioxide production (VE/VCO2), the ratio of effective alveolar ventilation to carbon dioxide production (VA/VCO2), the ratio of pulmonary dead space to tidal volume (Vd/Vt), and arterial PCO2 (PaCO2) were not correlated with age. At the exercise intensity of ventilatory anaerobic threshold, the PaCO2 increased, and the VA/VCO2 decreased, significantly with age, whereas the Vd/Vt was not related to age. Linear regression analysis demonstrated that the slope of the relationship between VE and VCO2 (deltaVE/deltaVCO2) and the slope of the relationship between VA and VCO2 (deltaVA/deltaVCO2) decreased with age. There were no gender differences in the regression slopes and the intercepts of the relationships. Results show that younger children breathe more during exercise to eliminate a given amount of CO2 to keep PaCO2 set point slightly but significantly lower than older children. This age dependence must be considered in investigating ventilatory control during exercise in children.

Identification of a highly encapsulated, genetically related group of invasive type III group B streptococci

Type III group B streptococci (GBS) isolated from Tokyo and Salt Lake City were classified according to the similarity of HindIII and Sse83871 restriction digest patterns (RDPs) of bacterial DNA. The bacteria were clustered into three RDP types, with excellent correlation between subtyping based on the two enzymes. The majority (91%) of invasive isolates obtained from neonates were RDP type III-3. The mean sialic acid content of the III-3 strains was higher than that of other type III strains. Closely related isolates were concordant for expression of the bacterial enzyme C5a-ase, but invasive strains were no more likely to be C5a-ase positive than were strains isolated from the genitourinary tract of pregnant women. These data indicate that a group of genetically related organisms with increased capsule production causes the majority of invasive type III GBS disease.