Renal vasodilating and diuretic actions of a selective endothelin ETB receptor agonist, IRL1620

The effects of a selective agonist for endothelin ETB receptors, Suc-[Glu9,Ala11,15]endothelin-1-(8-21), IRL1620, on renal hemodynamics and urine formation were studied in anesthetized dogs. Intrarenal arterial infusion of IRL1620 at a dose of 50 ng/kg/min increased renal blood flow from 3.37 +/- 0.30 (mean +/- S.E.) to a maximal value of 4.43 +/- 0.45 ml/g kidney weight per min (ml/g/min) at 9.1 +/- 1.0 min after the start of infusion, with no change in systemic blood pressure and heart rate. Urine flow rate increased and urine osmolality, osmolar clearance and free water reabsorption decreased significantly whereas glomerular filtration rate remained unchanged. In dogs given ibuprofen (12.5 mg/kg, i.v.) after the start of infusion of the peptide, renal blood flow increased slightly but significantly from 3.78 +/- 0.82 to 4.17 +/- 0.96 ml/g/min (1.0 +/- 0.1 min), followed by a gradual reduction in renal blood flow. In dogs given L-NG-nitroarginine (75 micrograms/kg/min), the renal blood flow decreased following intrarenal administration of IRL1620 (50 ng/kg/min). It is suggested that IRL1620 enhances the release of nitric oxide and prostaglandins in the kidney and promotes renal vasodilation. The IRL1620-induced reduction of urine osmolality and free water reabsorption was affected by neither ibuprofen nor L-NG-nitroarginine, thereby suggesting that the suppression of urine concentration did not seem to be linked to the enhanced production of nitric oxide or prostaglandins in the kidney.

Effects of ginseng in nephrectomized rats

Ginseng extract and its active component, saponin, were administered orally to nephrectomized rats for 90 d, and changes in blood and urine parameters and renal tissue lesions were assessed. Rats given saponin showed a significant decrease in the concentrations of blood urea nitrogen, creatinine and methylguanidine and a significant increase in total protein and albumin in the blood, with reduce urinary excretion of protein. There was also slight amelioration of the degree of mesangial proliferation, the severity of extratubular lesions and glomerular sclerotic lesions, and the extent of tubular interstitial lesions. However, these histological changes were inconspicuous in nephrectomized rats given ginseng extract.

Myasthenia gravis associated with Addison's disease

Idiopathic Addison's disease developed in a 52-year-old female with a 15-year history of myasthenia gravis. The association of myasthenia gravis with other autoimmune diseases is well known, however an association with Addison's disease is rare. It was speculated that the development of Addison's disease in this patient might have been due to common immunological abnormalities underlying these two diseases. We report this case and briefly discuss the pathogenetic mechanism of this association.

[Brain MRI findings in patients with initial cerebral thrombosis and the relationship between incidental findings, aging and dementia]

To estimate the relationship between aging, dementia and changes observed on magnetic resonance imaging (MRI) seen in elderly patients with cerebral thrombosis, MRI findings in 103 patients with an initial stroke event (thrombosis group) were compared with those of 37 patients with hypertension/diabetes (high risk group) and 78 patients without those disorders (low risk group). In addition to the causative lesions in the thrombosis group, periventricular hyperintensities (PVH), spotty lesions (SL), silent infarctions (SI), ventricular dilatation (VD), and cortical atrophy (CA) were analyzed in these groups. Infarctions located in the internal capsule/corona radiata were the most frequent causative lesion. Compared to the low risk group, a high incidence of patchy/diffuse PVH, SI, and severe CA was seen in both the thrombosis group and the high risk group. Widespread PVH and multiple SL increased with age in the thrombosis group, while severe CA was seen in each group. SI and VD tended to increase after age 60, though they were not significant. Dementia, diagnosed in 40 out of 78 patients, increased with age. Multivariate analysis revealed the degree of the effects of MRI findings on dementia to be marked in PVH, brain atrophy, causative lesions, and SL, in that order. These results indicated that diffuse PVH and brain atrophy, developing with age, promoted dementia in the elderly with vascular lesions. Moreover, they suggested that a variety of silent brain lesions recognized on MRI other than infarction can affect symptoms in the elderly.

[Early cytomegalovirus retinitis]

We report the clinical course of cytomegalovirus (CMV) retinitis associated with acquired immunodeficiency syndrome (AIDS) from the initial onset. The patient was a 40-year-old human immunodeficiency virus antibody-positive male with hemophilia A. He was diagnosed as having AIDS on the basis of pneumocystis carinii pneumonia. Ophthalmoscopic examination disclosed a small white punctate lesion at the macular area in his right eye. Because the lesion enlarged gradually with hemorrhages, it was suspected to be CMV retinitis. However, further examination was impossible due to his severe general condition. He died five months later and the autopsy disclosed disseminated CMV infection. Ocular histopathological examination revealed CMV retinitis. The earliest sign of CMV retinitis is supposed to be a white punctate retinal lesion, which becomes a small white patchy lesion resembling a cotton-wool spot. It may gradually progress to diffuse retinal involvement, frequently associated with hemorrhages.

Mast cells cultured from the peripheral blood of normal donors and patients with mastocytosis originate from a CD34+/Fc epsilon RI- cell population

Mast cells may be cultured from human peripheral blood in the presence of recombinant human stem cell factor (rhSCF). The characteristics of the cells in peripheral blood that give rise to mast cells are unknown. Because mast cell precursors in human marrow are CD34+, human peripheral blood mononuclear cells from patients with mastocytosis and normal controls were sorted on the basis of CD34 expression and the positive and negative cell populations were cultured in rhSCF, recombinant human interleukin-3 (rhIL-3), or both for 6 weeks. Cell cultures were examined every 2 weeks for total and mast cell number and cell differential using Wright Giemsa and acid toluidine blue stains and antibodies to mast cell tryptase and chymase, cell-associated histamine, and expression of CD34, c-kit, Fc epsilon RI, and Fc gamma RII using flow cytometric analysis. The ultrastructural anatomy of mast cells was examined by electron microscopy. Peripheral blood CD34+ cells cultured in rhSCF with or without rhIL-3 gave rise to cell cultures consisting of greater than 80% mast cells by 6 weeks. CD34+ cells cultured in rhIL-3 alone did not give rise to mast cells, whereas rhIL-3 plus rhSCF increased the final mast cell number eightfold when compared with cells cultured in rhSCF alone. Mast cells increased concomitantly with a decrease in large undifferentiated mononuclear cells. CD34- cells did not give rise to mast cells. Histamine content per cell at 6 weeks was approximately 5 pg. Electron microscopy of 4-week cultures showed immature mast cells containing predominantly tryptase-positive granules that were either homogeneous or contained lattice structures, partial scroll patterns, or central dense cores and mixtures of vesicles, fine granular material, and particles. The CD34+ population at day 0 expressed Kit (65%) and Fc gamma RII (95%), but not Fc epsilon RI, by fluorescence-activated cell sorter analysis. At 6 weeks, CD34+-derived mast cells exhibited Fc epsilon RI in addition to Kit and Fc gamma RII, and were negative for CD34 antigen. Patients with mastocytosis showed a higher number of mast cells per CD34+ cell cultured compared with normal controls. Thus, the mast cell precursor in human peripheral blood is CD34+/Fc epsilon RI- and gives rise to mast cells in the presence of rhSCF with or without rhIL-3, and the number of mast cells arising per CD34+ cell in culture is greater when the CD34+ cells are obtained from patients with mastocytosis compared with normal subjects.

[Serum IgA-fibronectin complex in children with various renal diseases]

IgA-Fibronectin complex (IgA-FN) has been found in the circulation of patients with IgA nephropathy (IgAN). It has been suggested that circulating IgA-FN is related to IgA deposits in the mesangial area following mesangial matrix expansion in IgAN. We investigated serum IgA-FN in patients with various renal diseases, and examined the relationship between IgA-FN and the clinico-pathological findings. Serum IgA-FN level was measured by enzyme-linked immunosorbent assay (ELISA) in 35 patients with IgAN, 20 patients with Henoch-Schönlein purpura nephritis (HSPN), and other various renal diseases in children. IgA-FN in patients with IgAN was significantly higher than in healthy subjects and patients with minimal change nephrotic syndrome. However some patients with membranoproliferative glomerulonephritis and lupus nephritis had a high level of IgA-FN. The increase in IgA-FN was correlated with macroscopic hematuria and the degree of proteinuria and mesangial matrix expansion in IgAN. Thus, we concluded that the level of IgA-FN is associated with mesangial matrix expansion.

[A study on glomerular hypertrophy in various renal disease]

We studied the contributions of glomerular hypertrophy in renal disease. The patients were 20 cases of IgA nephropathy with prolonged proteinuria, 13 cases of Alport syndrome and 12 cases of focal glomerular sclerosis (FGS). All patients had a normal creatinine level on renal biopsy. We determined the mean glomerular tuft area in the equatorial region of five glomeruli that showed no sclerotic change in each patient using an image analyzer and compared the value with the mean value in normal controls. Glomerular hypertrophy was defined as a value over the mean glomerular tuft area +1SD of normal controls. Glomerular hypertrophy was found in 14 IgA nephropathy cases (70.0%), 4 Alport syndrome cases (30.7%) and 8 FGS cases (66.7%). The incidence of glomerular hypertrophy was significantly higher in IgA nephropathy than in Alport syndrome and FGS showed a higher tendency compared with Alport syndrome. Of the patients with renal insufficiency, 4 of 6 IgA nephropathy cases (66.6%), 0 of 5 Alport syndrome cases (0%) and 1 of 3 FGS cases (33.3%) showed glomerular hypertrophy, IgA nephropathy patients showed the highest incidence of glomerular hypertrophy. The interval between the final biopsy and renal insufficiency showed no significant difference in this study. In IgA nephropathy, obsolescent glomeruli were significantly increased in the group in which the glomerular tuft area was over the mean +2SD compared with the group with an area less than the mean +2SD. FGS cases showed no relationship between the ratio of obsolescent glomeruli to whole glomeruli and glomerular hypertrophy. This study suggested that glomerular hypertrophy may cause declining renal function in IgA nephropathy, but not in Alport syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Involvement of phosphatidylinositol 3-kinase in Fc gamma receptor signaling

Wortmannin, a potent and selective inhibitor of phosphatidylinositol (PI) 3-kinase (Okada, T., Sakuma, L., Fukui, Y., Hazeki, O., and Ui, M. (1994) J. Biol. Chem. 269, 3563-3567), prevented Fc receptor for IgG (Fc gamma R)-dependent phagocytosis of the human monocytic cell line U937 or guinea pig neutrophils. Cross-linking of Fc gamma R on the surface of U937 cells increased PI 3-kinase activity that was immunoprecipitated with antibody against phosphotyrosine or antibody against the 85-kDa regulatory subunit of PI 3-kinase. Specific cross-linking of Fc gamma R subclass Fc gamma RI or Fc gamma RII, using monoclonal antibodies against each receptor subclass and the F(ab')2 fragment of goat antibody against mouse IgG, increased anti-phosphotyrosine-precipitable PI 3-kinase activity. Treatment of cells with anti-Fc gamma RIII antibody plus the same F(ab')2 did not affect the activity, reflecting the lack of Fc gamma RIII in U937 cells. Fcy gamma R stimulation triggered prominent tyrosine phosphorylation of several proteins, among which the 115-kDa peptide showed strong association with PI 3-kinase. Thus, Fc gamma R appears to be coupled functionally, via a tyrosine kinase, to PI 3-kinase, which may regulate the phagocytotic activity of the cells.

Morphometry of the kidney in rat pups from uninephrectomized mothers

BACKGROUND

The present study was designed to explore whether maternal renal dysfunction affects fetal kidney development and if the effects are lasting during the postnatal development.

METHODS

Kidneys of 1-day-old and 6-week-old pups from mothers which were uninephrectomized on day 5 of gestation were studied.

RESULTS

One day after birth, both the number of immature glomeruli and average volume of mature glomeruli of the neonates from uninephrectomized mothers were significantly larger than those from sham-operated mothers. Six weeks after birth, no significant differences in parameters of the kidney were observed between the pups from uninephrectomized and those from sham-operated mothers. Furthermore, blood urea nitrogen (BUN) concentration in adult female rats was determined at various days after uninephrectomy. BUN concentration in uninephrectomized rats was significantly higher than that in sham-operated ones.

CONCLUSIONS

These results suggest that the fetal kidney development is accelerated by the elevated BUN level following maternal uninephrectomy and that the renotropic activity does not last during the postnatal developmental period.

Electrocardiographic diagnosis of left ventricular hypertrophy improved by considering both QRS voltage and ST-T criteria

We evaluated the usefulness of a combination of QRS voltage and the pattern of ST-T abnormality in the electrocardiographic diagnosis of left ventricular hypertrophy (LVH) in 100 middle-aged men: 32 normals, 59 with hypertension (HT), and 9 with hypertrophic cardiomyopathy (HCM) with evidence of LVH (RV5 or RV6 > or = 2.6 mV, SV1 + RV5 or SV1 + RV6 > or = 3.5 mV). They The subjects were classified into three groups based on ST-T pattern: normal (group N), early strain (group ES), and strain (group S). Echocardiographic evidence of LVH was present in 52.0% (52/100) of the subjects: 72.8% (43/59) of the patients with HT, all 9 patients with HCM, and none of the 32 normals. Echocardiographic evidence of LVH was present in 31.3% (20/64) of group N, 73.3% (11/15) of group ES, and all 21 subjects of group S. In patients with HT, the incidence of echocardiographic LVH was higher in group S (100%) than in both group ES (78.6%) and group N (60.6%). QRS voltage (RV5, RV6, RV5 + SV1, and RV6 + SV1) was significantly correlated with interventricular spetal thickness (IVST), IVST+LVPWT/2, and LV mass, as determined by echocardiography, in patients with LVH (IVST or left ventricular posterior wall thickness (LVPWT) of > or = 12 mm) (r = 0.55 to r = 0.75, p < 0.05), but not in patients without LVH (IVST and LVPWT < 12 mm). There were significant correlations between QRS voltage indices (RV5, RV6, RV5 + SV1, and RV6 + SV1) and IVST, IVST+LVPWT/2, and LV mass in group S (r = 0.68 to r = 0.86, p < 0.05), but not in group N. Values for IVST and LV mass were significantly greater in group S than in groups ES or N. The combination of QRS criteria and ST-T findings reflected the echocardiographic assessment of LVH, especially in patients with HT.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative analysis of mutually competitive binding of human Raf-1 and yeast adenylyl cyclase to Ras proteins

Ras proteins appear to have two distinct downstream effectors, adenylyl cyclase in Saccharomyces cerevisiae and a product of raf-1 protooncogene in higher organisms. We found that in vitro activation of adenylyl cyclase by yeast Ras2 and human H-Ras proteins is subject to competitive inhibition by its leucine-rich repeats domain and by the N-terminal regulatory domain of human Raf-1 protein. Kinetic analyses of the inhibition patterns enabled us to determine exact dissociation constants (Kd) of the two polypeptides for Ras2 and H-Ras. The leucine-rich repeats domain bound to the posttranslationally modified Ras2 with the Kd of approximately 13 nM, which was close to the value (7 nM) of the whole adenylyl cyclase. The Kd of Raf-1 for the modified H-Ras, 3.5 nM, was significantly lower than that for Ras2, 24 nM, whereas adenylyl cyclase bound preferentially to Ras2. Similar inhibition was also observed in vivo by suppression of RAS2Val-19-dependent heat shock sensitivity and of Ras-dependent cAMP response to glucose upon overexpression of Raf-1 in yeast. These results indicate that the leucine-rich repeats domain contains the Ras protein-binding site and that Raf-1 and adenylyl cyclase, sharing no structural homology with each other, bind to a similar, if not identical, region of Ras with comparable affinities.

[Detection of Mycobacterium tuberculosis in transbronchial biopsy specimens by polymerase chain reaction]

Polymerase chain reaction (PCR) for the rapid detection of Mycobacterium tuberculosis was used to test 30 clinical specimens (transbronchial biopsy specimens) from patients in whom tuberculosis was suspected on chest X-ray. In these patients, 15 cases were histologically diagnosed as tuberculosis. Among them, M. tuberculosis was detected in 8 specimens by PCR. Of 8 PCR positive specimens, 7 were also positive by smear and culture; the other was negative by smear and positive by culture. On the other hand, 15 cases were therapeutically diagnosed as the tuberculosis and these specimens showed negative results in neither PCR nor microbiological tests. We conclude that the PCR method is useful for rapid and direct detection of M. tuberculosis in transbronchial biopsy specimens.

Detection of DNA of causative agent of spotted fever group rickettsiosis in Japan from the patient's blood sample by polymerase chain reaction

The polymerase chain reaction (PCR) was applied for the etiological diagnosis of spotted fever group (SFG) rickettsiosis in Japan. Nucleotide primers derived from the 17-kDa antigen gene of Rickettsia rickettsii primed a rickettsia-specific 246-base-pair product for all of the Katayama, Abe, Misaka and Kojima strains, which we had isolated previously. Moreover, we were able to detect the same product by PCR amplification from the peripheral blood of a patient in the acute stage of the illness. The PCR method is considered to be useful for rapid etiological diagnosis of SFG rickettsiosis in Japan.

Novel theta class glutathione S-transferases Yrs-Yrs' and Yrs'-Yrs' in rat liver cytosol: their potent activity toward 5-sulfoxymethylchrysene, a reactive metabolite of the carcinogen 5-hydroxymethylchrysene

Two novel theta class glutathione S-transferases (GSTs), designated Yrs-Yrs' and Yrs'-Yrs', were isolated from rat liver cytosol and purified to homogeneity. Polyclonal antibody raised against the previously reported theta class GST Yrs-Yrs (Hiratsuka, A. et al., J. Biol. Chem. 265, 11973 (1990)) cross-reacted with GSTs Yrs-Yrs' and Yrs'-Yrs'. These three theta class GSTs had different pI values and were separated by chromatofocusing. The enzyme subunit Yrs' was separated from Yrs by reverse partition HPLC, but identical to Yrs in the first 37 N-terminal amino acid sequence. Like GST Yrs-Yrs, both GSTs Yrs-Yrs' and Yrs'-Yrs' were not retained on an S-hexyl-GSH affinity column and had little activity toward 1-chloro-2,4-dinitrobenzene. However, they showed potent activities toward the reactive sulfate ester of the carcinogen, 5-hydroxymethylchrysene. GSTs Yrs-Yrs and Yrs'-Yrs' showed much higher GSH peroxidase activities toward arachidonate hydroperoxide than did rat liver alpha class GST Ya-Ya.

HIV type 1 infection of CD4+ T cells depends critically on basic amino acid residues in the V3 domain of envelope glycoprotein 120

The third variable domain (V3 domain) of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 is a major determinant of phenotypic variability. The V3 domain of HIV-1 has many basic amino acid residues. Lymphocytotropic HIV-1 tends to have a V3 domain with a higher density of positive charge than does monocytotropic HIV-1. The importance of basic residues in the V3 domain for the HIV-1 infectivity, however, has not been well investigated. Here we show that mutation of basic amino acid residues at positions 303, 306, 309, 313, and 325 in the V3 domain of the lymphocytotropic isolate NL4-3 results in a dramatic elimination of both virus infectivity and syncytium-inducing ability. Three basic amino acid substitutions (at position 306, 309, and 313) induced a decrease in the binding ability of two kinds of neutralizing antibodies (NEA9284 and 0.5 beta) that recognize a different site in the V3 domain. This suggests that the basic residues play an important role in maintaining the tertiary structure of the V3 domain. Monocytotropism was not simply dependent on either decreased positive charge in the V3 domain of NL4-3 or on mutation of lysine to glutamate at position 320, which is a characteristic amino acid of monocytotropic HIV-1. These findings contribute to our understanding of the significance of basic residues on the function of envelope glycoprotein.