Regulation of immune function by protein tyrosine phosphatases

CD45 is a leukocyte transmembrane protein tyrosine phosphatase that functions in lymphocyte activation by increasing the kinase activity of Src family members. In contrast, an intracellular protein tyrosine phosphatase that contains Src homology 2 domains, SHP, is required to inactivate receptors. Recent studies have examined the mechanisms of interaction and regulation of these enzymes.

Type 3 GM1 gangliosidosis: clinical and neuroradiological findings in an 11-year-old girl

An 11-year-old Japanese girl was diagnosed as having type 3 GM1 gangliosidosis by clinical symptoms and enzyme assay. She was the youngest among the patients with type 3 GM1 gangliosidosis whose clinical and neuroradiological findings have been documented. Clumsiness since early infancy and dystonia since early childhood which progressed slowly without mental deterioration and dysmorphism led us to the diagnosis of type 3 GM1 gangliosidosis. Genotype determination showed point mutation in exon 2 of the beta-galactosidase gene, which is common among the patients reported in Japan. T2-weighted MRI demonstrated bilateral symmetrical hypointensity in the putamen and globus pallidus. Single photon emission computed tomography using 99mTc-HMPAO showed bilateral hyperperfusion in the basal ganglia which decreased gradually during 1 year of observation. Twenty-two patients with type 3 GM1 gangliosidosis reported in the literature whose onset was at under 15 years of age were reviewed.

Hypovolemic hemorrhagic shock (an experimental study)

With the objective of studying the natural defense mechanisms against traumatic hemorrhages, 20 mice were studies. Some of the large vessels were examined histologically after fixing with formaldehyde, in cases of bleeding, bleeding + hemodilution and controls. In the hemo-diluted group, important alterations in the distribution of the components of the blood stream were confirmed and in one case, there was extravasation of liquid poor in cellular elements. The results show that hemodilution is an unfavorable condition for the natural defense mechanisms against hemorrhage. The repercussion of these experimental results on clinical cases of traumatic hemorrhage is speculated.

Accumulation of immature CD3-CD4+CD8- single-positive cells that lack CD69 in epithelial cell tumors of the human thymus

Human thymomas are epithelial tumors that are associated with a large number of nonneoplastic T cells of mainly immature phenotype, suggesting that epithelial cells of thymomas retain the function of thymic cortical epithelium. We report here that a large proportion (16-85%, mean +/- SD 58 +/- 22%, n = 17) of CD4+ single-positive T cells within the thymoma lack cell surface expression of CD3 and also of CD69, an early activation antigen that is expressed by positively selected thymocytes. Normal thymus had this CD4+CD8-CD3- population at much lower levels (12 +/- 7%, n = 11). It has been reported that in the human the CD4+CD8-CD3- cells are the predominant population that is intermediate between the CD4-CD8- double-negative and CD4+CD8+ double-positive stages. In contrast to CD4+ single-positive cells, most of the CD8+ single-positive cells in the thymoma as well as in the normal thymus expressed CD69 and a high level of CD3. A partial explanation of these observations is that the epithelial cells of thymoma were unable to positively select all the immature thymocytes generated in the thymoma. This relative inefficiency of positive selection could not be attributed solely to the paucity of MHC class II expression in the thymoma.

[Characterization of Trypanosoma cruzi strains isolated from patients with heart transplantation]

Three strains of Trypanosoma cruzi were isolated in Chagas' disease patients transplanted for heart failure. These strains were studies in an experimental model of Chagas' disease, in mice, with evaluation of parasitic load, mortality and extension of inflammatory infiltrates in the heart. These parameters were compared with those of the standard strain Y. The strains had differences in the studies parameters, but there was no clear relationship between them and the post-transplant evolution of the patients, probably the clinical response is multifactorial and derives only in part from biological characteristics of the infecting T. cruzi strain, as measured in our model.

Effects of nifedipine on hepatic venous pressure gradient and portal vein blood flow in patients with cirrhosis

We investigated the effects of nifedipine on splanchnic haemodynamics in 13 patients with cirrhosis and portal hypertension, and in 10 control subjects using hepatic venous catheterization and pulsed Doppler ultrasound. There were no significant changes in systemic or splanchnic haemodynamics in control patients. In contrast, systemic vasodilatation, evidenced by significant decreases in mean arterial pressure and systemic vascular resistance, was observed in patients 20 min after sublingual application of 10 mg nifedipine. Moreover, hepatic venous pressure gradient and portal vein blood flow significantly increased after nifedipine administration. There was a significant correlation between the percentage increases in portal vein blood flow and in hepatic venous pressure gradient. However, no correlation was found between the percentage change in cardiac output and that in portal vein blood flow. Thus the increase in portal vein blood flow appears to be related to splanchnic arterial vasodilatation by nifedipine. Consequently, nifedipine has deleterious effects on portal haemodynamics in patients with cirrhosis. As nifedipine may potentially increase the risk of variceal haemorrhage in patients with less advanced varices, this drug should be used with caution in patients with chronic liver disease.

Effects of xanthine derivatives on phosphatidylcholine secretion in primary culture of rat type II pneumocytes

Xanthine derivatives, pentoxifylline, aminophylline, theophylline and chinoin-170, increased phosphatidylcholine secretion in a primary culture of rat type II pneumocytes. However, these xanthines alone had no effect on intracellular cAMP levels in type II pneumocytes. In contrast, terbutaline-induced secretion of phosphatidylcholine was augmented by these xanthines, and the augmentation depended on the increase of cAMP levels. These results suggest that the xanthines induce phosphatidylcholine secretion possibly through cAMP-dependent and cAMP-independent pathways in the primary culture of rat type II pneumocytes.

Intestinal transit and opaque enema study in chagasic mice

The report concerns as experimental study utilizing thirty-three mice inoculated subcutaneously with 1000 blood forms of Trypanosoma cruzi. Intestinal transit and morphology of colon were studies by means of X-rays. In subacute stage intestinal transit was normal. In chronic stages the mice displayed a delay in evacuation time. In one out of 12 animals the opaque enema documented the existence of megacolon.

The effects of chronic endoscopic variceal sclerotherapy on systemic and splanchnic hemodynamics in patients with cirrhosis

The aim of this study was to determine whether endoscopic variceal sclerotherapy affects systemic or splanchnic hemodynamics. We measured hemodynamic parameters before and after the first course of sclerotherapy in 35 patients with cirrhosis. Following sclerotherapy, there was a significant decrease in cardiac index and a significant increase in systemic vascular resistance. Changes in hepatic venous pressure gradient varied from patient to patient with no statistically significant change in the group overall. However, all 20 patients with a decline in the hepatic venous pressure gradient had a concomitant decrease in cardiac index and/or a large extravariceal shunt. The multivariate analysis disclosed that the decrease in cardiac index was a statistically significant contributor for the decline in hepatic venous pressure gradient. We conclude that the obliteration of esophageal varices by sclerotherapy significantly reverses the hyperdynamic circulatory state in patients with cirrhosis. Spontaneous changes in systemic hemodynamics and the interaction with hepatic hemodynamics must be taken into account when evaluating hepatic hemodynamics in patients undergoing variceal sclerotherapy.

[A new index of disease activity in Crohn's disease]

A comprehensive assessment including subjective and objective parameters seems to be essential for evaluation of disease activity in Crohn's disease. The aim of the present study was to develop an activity index (AI) of Crohn's disease, composed of both subjective and objective variables. Data composed of a total 132 clinical examinations in 100 patients with Crohn's disease were used to determine the AI. Three physicians independently evaluated disease severity in each patient. Stepwise multiple regression analysis was carried out with the overall evaluation as a dependent variable, and with 18 parameters as independent variables. Analysis showed that the following seven variables had a significant correlation with physician's overall evaluation: abdominal pain, abdominal tenderness, complications, C-reactive protein (CRP), body temperature, diarrhea, and body mass index (BMI). AI was expressed as follows: AI = 3.5 x abdominal pain + 3 x abdominal tenderness + 3 x complications + CRP + 3 x body temperature + 4 x diarrhea - 0.4 x BMI. AI values below 15 corresponded to inactive disease, values between 15 and 25 to mild disease, values between 25 and 35 to moderate disease, and values above 35 to severe disease. This study suggests that the activity index is useful for evaluation of the effect of medical treatment in Crohn's disease.

Hypercalcemia caused by PTH-rP associated with lung metastasis from urinary bladder carcinoma: an autopsied case

We analyzed the parathyroid-related protein (PTH-rP) content in tissue specimens obtained from a 61-year-old man with hypercalcemia associated with lung metastasis from urinary bladder carcinoma using radioimmunoassay and immunohistochemistry. Radioimmunoassay showed that the PTH-rP content was higher in metastatic lung tumor tissue than in non-tumorous lung tissue. Immunohistochemical analysis revealed the presence of PTH-rP in tumor cells. Furthermore, proliferation of osteoclasts was found in bone marrow at autopsy. The results suggest that PTH-rP induced humoral hypercalcemia of malignancy in a patient with urinary bladder cancer.

Anxiety, depression, psychosomatic symptoms and autonomic nervous function in patients with chronic urticaria

Most reports on the psychological analysis of chronic urticaria have concentrated on psychodynamic theories of causation of the disease. For the present study, we used three kinds of psychological tests as well as electrocardiography to estimate anxiety, depressiveness, psychosomatic symptoms and autonomic nervous functions in 30 outpatients with chronic urticaria and 39 normal controls. For evaluation we used the manifest anxiety scale (MAS), self-rating depression scale (SDS), Cornell medical index (CMI) and convergence of variance of R-R interval (CVR-R). Psychologically positive responses to any one of the tests were seen in 70.0% of the chronic urticaria patients, but in only 25.6% of the controls. These differences all showed statistical significance (P < 0.01). The In(CVR-R) (Y) and age (X) suggested a linear regression, but although the regression slope was steeper for the urticaria group (Y = 2.924-0.027X) than for the controls (Y = 2.702-0.023X), the difference was not statistically significant. These data indicate that patients with chronic urticaria are more anxious, depressive and psychosomatic symptom-prone than normal controls. In conclusion, we suggest that chronic urticaria patients should be diagnosed and treated both dermatologically and psychologically.

Effect of adrenomedullin on renal hemodynamics and functions in dogs

In order to elucidate the role of adrenomedullin in the kidney, we investigated the effects of adrenomedullin on renal hemodynamics and urine formation in anesthetized dogs. Intrarenal arterial infusion of adrenomedullin (0.8, 4 and 20 ng.kg-1.min-1) elicited dose-dependent increases in renal blood flow (by 10, 26 and 37%, respectively) with no change in blood pressure or heart rate, indicating a renal vasodilatory action of adrenomedullin. The glomerular filtration rate did not increase with the lower two doses, but increased marginally by 9% at the highest dose. Infusion of adrenomedullin at the rates of 4 and 20 ng.kg-1.min-1 increased urine flow and the urinary excretion of sodium and potassium dose dependently. Arterial and renal venous plasma renin activity was unaffected by adrenomedullin. These findings indicate that adrenomedullin is a potent renal vasodilatory peptide with a diuretic action. Since the threshold for the renal vasodilatory action of adrenomedullin is close to its physiological concentration in human plasma, adrenomedullin may play an important role in the regulation of renal function.

Physiological expression of the 2',5'-oligoadenylate synthetase gene in mouse intestine

2',5'-Oligoadenylate synthetase (2-5A synthetase) is an enzyme induced by interferon (IFN) that is considered to play an important role in IFN action. The normal mouse, not treated exogenously with any IFN or IFN inducers, has been shown to have an enhanced level of 2-5A synthetase activity, which is distributed among several lymphoid tissues. In the present report, we investigated the expression of the 42-kD 2-5A synthetase mRNA in the organs of normal mice using RNA blot hybridization and reverse transcriptase polymerase chain reaction (RT-PCR). Among the organs tested, intestinal tissues had the highest levels of this mRNA. Furthermore, the 42-kD 2-5A synthetase mRNA was expressed in intestines from germ-free mice and fetuses. Immunoblotting analysis using a monoclonal antibody against the 42-kD 2-5A synthetase revealed that the 42-kD enzyme as well as a cross-reactive protein of 30 kD were produced in the organs of the normal mouse.