[Clinical experience of image-guided neurosurgery with a frameless navigation system (StealthStation)]

We have applied the frameless navigation system (StealthStation) to various neurosurgical procedures to examine its usefulness. The system consists of a UNIX based workstation that creates triplanar and 3-dimensional images; an infrared optical digitizer with camera array; a reference-light-emitting diode (LED) array (e.g., reference array); and pointer probe modified by the addition of LEDs. This system was used to assist in placing a minimal skin incision and craniotomy in 4 cases, to determine the tumor/brain interface in 2 cases, to target the subcortical lesion in one case, and to correlate bony structure with a skull base tumor in 3 cases. The combined use with magnetic source imaging of the somatosensory cortex allowed a fast orientation of eloquent areas in 2 cases with peri-Rolandic tumor. This system, thus, was proved to be a useful adjunct to open-tumor biopsy or resection.

Gene expression of CC chemokines in experimental acute tubulointerstitial nephritis

The infiltration of mononuclear leukocytes into glomeruli or the interstitium is a feature in most forms of glomerular diseases. CC chemokines, mostly chemoattractants for mononuclear leukocytes, are molecules that are potentially responsible for the recruitment of these cells in the kidney. We previously reported that the gene expression of six CC chemokines-MCP-1, MCP-3, MIP-1alpha, MIP-1beta, RANTES, and TCA3-was enhanced in a rat model of crescentic glomerulonephritis, the most severe form of glomerulonephritis. In this study we analyzed their gene expression in a model of another type of kidney disease, acute nephrosis accompanied by tubulointerstitial lesions, which is induced by an injection of puromycin aminonucleoside. Because leukocyte infiltration in this model is much more prominent in the interstitium than in glomeruli, we analyzed their gene expression in the renal cortex. On day 3, when the level of urinary protein was slightly but significantly increased but the number of interstitial leukocytes was unchanged, the enhanced expression of mRNAs for MCP-1, MCP-3, and TCA3 was observed. On day 5, the numbers of interstitial monocytes and lymphocytes significantly increased, and the levels of the mRNA expression of the above chemokines were still higher than the control animals, whereas the levels of mRNAs for MIP- 1alpha, MIP-1beta, and RANTES were not higher or were only slightly higher than the control ones. These results suggest that multiple CC chemokines may play a role in the recruitment of leukocytes in this model and that the expression pattern of CC chemokines depends on the type of kidney injury.

A historical cohort mortality study of workers exposed to asbestos in a refitting shipyard

To investigate the risks of developing asbestos-related diseases we conducted a historical cohort mortality study on 249 ship repair workers (90 laggers and 159 boiler repairers) in a single U.S. Navy shipyard in Japan. We successfully identified the vital status of 87 (96.7%) laggers and 150 (94.3%) boiler repairers, and, of these, 49 (56.3%) and 65 (43.3%) died, respectively, during the follow-up period from 1947 till the end of 1996. Our in-person interviews with some of the subjects clarified that asbestos exposure was considered to be substantially high in the 1950-60s, decreased thereafter gradually but remained till 1979 in the shipyard. The laggers, who had handled asbestos materials directly, showed a significantly elevated SMR of 2.75 (95% C.I.: 1.08-6.48) for lung cancer. The risk developing the disease was greater in the laggers after a 20-year latency (SMR = 3.42). Pancreatic cancer yielded a greater SMR than unity (7.78, 90% C.I.: 2.07-25.19) in a longer working years group. Four laggers died from asbestosis. The boiler repairers, who had many chances for secondary exposure to asbestos and a few for direct exposure, showed no elevation of the SMR of lung cancer overall, but there was a borderline statistically significant SMR of 2.41 (90% C.I.: 1.05-5.45) in a longer working years group. One boiler repairer died from mesothelioma and four from asbestosis.

Production of functional rat liver PSP protein in Escherichia coli

An efficient Escherichia coli expression system for the production of a perchloric acid-soluble protein (PSP) has been constructed. Complementary DNA encoding PSP was inserted into an inducible bacterial expression vector pGEX-4T-1. After the plasmid introduced into E. coli was expressed by isopropyl 1-thio-beta-D-galaetopyranoside (IPTG), the recombinant product was purified by glutathione-Sepharose 4B affinity chromatography. The purified product showed the expected NH2-terminal sequence, but the translation inhibitory activity of this product was 10 times lower compared with that of authentic PSP isolated from rat liver.

Multiple combined indirect procedure for the surgical treatment of children with moyamoya disease. A comparison with single indirect anastomosis with direct anastomosis

Considering three different bypass procedures now in use, (single indirect nonanastomotic bypass procedure, multiple combined indirect (MCI) nonanastomotic procedure and direct anastomosis), the authors attempted to identify the most appropriate bypass procedure for treating ischemic-type moyamoya disease in children.

The authors performed three procedures (the original encephaloduroarteriosynangiosis [EDAS] alone, the frontotemporoparietal combined indirect bypass procedure, and the superficial temporal artery-middle cerebral artery [STA-MCA] anastomosis with encephalomyosynangiosis [EMS]) on 72 hemispheres in 50 patients with pediatric moyamoya disease. Analyses were then performed to compare postoperative collateral vessel formation found on angiograms, complications, and clinical improvements. Postoperative collateral formations were observed in more than two-thirds of the MCA distribution after the EDAS alone, the MCI procedure, and the direct anastomosis in 44%, 52%, and 74% of the surgically treated hemispheres, respectively. In addition, frontal encephalomyoarteriosynangiosis of the MCI bypass procedure formed collateral vessels of the anterior cerebral artery distribution in 94% of the treated hemispheres. Postoperatively, clinical symptoms resolved in 56%, 63%, and 74% of the treated sides 1 year after EDAS alone, MCI procedure, and the direct anastomosis, respectively. One patient suffered a minor stroke after EDAS alone, two patients developed epidural hematomas after the MCI procedure, and one patient suffered a major stroke and one patient a minor stroke after undergoing direct anastomosis.

The direct anastomosis procedure was found to result in the best postoperative collateral vessel formation and clinical improvement. However, the single and multiple combined indirect nonanastomotic bypass procedures were found to be safer than direct anastomosis. Furthermore, the frontotemporoparietal combined indirect bypass procedure caused the formation of collateral circulation not only in the MCA but also in the ACA distribution. Based on analysis of these findings, the authors recommend the MCI procedure as the appropriate surgical procedure in the treatment of children with moyamoya disease, although the best treatment is the STA-MCA anastomosis with EMS when feasible.

Expression of lymphotactin mRNA in experimental crescentic glomerulonephritis

Lymphotactin (LTN) is the sole member of C chemokine, the third subfamily of chemokines. LTN has been shown to be a chemoattractant specific for CD8+ cells and/or natural killer (NK) cells, and to be produced by CD8+ T cells, NK cells, and mast cells. However, there have been no reports describing its expression in clinical or experimental models of diseases so far. Since glomerular infiltration of CD8+ cells is prominent in an animal model of crescentic glomerulonephritis induced in WKY rats by an injection of anti-glomerular basement membrane antibody, we investigated the gene expression of LTN in this model. LTN mRNA was not detected in normal glomeruli but was detected at 0.5 h after the antibody injection, which detection preceded the infiltration of CD8+ cells. The expression of LTN mRNA peaked on day 3 and decreased thereafter. We next studied the expression of LTN mRNA in cultured glomerular and vascular cells, and found that glomerular mesangial and vascular endothelial cells could express LTN mRNA when stimulated with IL-1beta. These results indicate that the gene expression of LTN is enhanced in the animal model of glomerulonephritis and that intrinsic renal cells are the potential source of the gene expression of LTN in the kidney.

A simple procedure for the isolation of rat kidney lysosomes

BACKGROUND

A procedure for the isolation of highly purified lysosomes from normal rat kidney is described.

METHODS

The method depends on the swelling of mitochondria when the postnuclear supernatant fraction is incubated with 2 mM Ca2+. The lysosomes can then be separated from the swollen mitochondria by Percoll density gradient centrifugation.

RESULTS

The lysosomal fraction obtained by our method was enriched more than 30-fold in terms of marker enzymes with a yield of about 11%. Electron microscopic examination and the measurement of the activities of marker enzymes for various subcellular organelles indicated that our lysosomal preparation was essentially free from contamination by other organelles.

CONCLUSION

We believe that this procedure for isolating kidney lysosome will be useful in the study of the mechanisms of specific modification, processing and catabolism of proteins.

cDNA cloning, expression, and characterization of the human bifunctional ATP sulfurylase/adenosine 5'-phosphosulfate kinase enzyme

A cDNA encoding the human bifunctional ATP sulfurylase/adenosine 5'-phosphosulfate (APS) kinase was cloned and sequenced. The enzyme contains an APS kinase domain in its N-terminal portion and an ATP sulfurylase domain in its C-terminal portion. Recombinant full-length enzyme and its constituent APS kinase and ATP sulfurylase domains were individually expressed, purified, and shown to have their respective enzymatic activities.

Characterization of fibronectin-related substances in normal and passive Heymann nephritis rats

The excretion mechanism of fibronectin (FN)-related substances into the urine of normal and passive Heymann nephritis (PHN) rats was studied using enzyme immunoassay and immunoblot analysis. In normal rats, a small amount (0.20+/-0.067 microg/d) of FN-related substances, composed of 55- and 65-kDa FN fragments derived from the central cell-binding (Cell) domain of FN, were constitutively excreted into the urine. When PHN was induced in rats by the injection of an anti-Fx1A antibody, an increased excretion (4.96+/-3.51 microg/d) of intact FN and large (Mr > 100-kDa) FN fragments containing the Cell and the other functional domains were seen. The PHN induction also caused the appearance of a considerable amount of Cell domain-containing FN fragments in plasma. Both the renal cortex homogenates of normal and PHN rats were capable of degrading plasma FN to generate the Cell domain-containing large FN fragments. Degradation of FN by the renal cortex homogenate was shown to be due to metal and/or thiol proteinase(s). These results suggest that the PHN-induced urinary excretion of FN fragments may be due to the degradation of plasma FN by renal proteinases that may be leaked upon PHN induction.

Operative approaches to the pineal region tumors

Until the introduction of microsurgery, the surgical treatment of pineal region tumors had very poor results with high mortality and morbidity. However, there have been remarkable improvements with modern surgical technology and advanced knowledge. Now the main surgical approaches to pineal region tumors are the occipital transtentorial approach and the infratentorial supracerebellar approach. Recently the neuroendoscopic approach has been added. The surgical approach and any supplementary treatment should be selected in each case according to the nature of the individual tumor. The forms of treatment practiced by ourselves, including neuroendoscopic surgery, are presented, and the surgical treatments now applied are discussed.

Micro-anatomical study of the carotid cave

The surgical treatment of aneurysms located in the carotid cave is often hazardous and difficult. We studied the micro-anatomy of the carotid cave and its neighbourhood by microscopic observation and histological examination using 50 sides from 25 autopsy cases. The carotid caves were found in 34 out of the 50 sides (68%) examined and were usually located in the posteromedial aspect of the carotid dural ring. They were classified into three types according to the topographic micro-anatomy: the slit-type (17/50, 34%) which showed a small, thin recess of the dura mater with fine connective tissue loosely adhered to the carotid wall; the pocket-type (12/50, 24%) which had a definite dural pouch with the apex attached to the vessel wall; and the mesh-type (5/50, 10%) which formed a slit- or pocket-type dural cave covered with a mesh-like dural roof. The remaining 16 sides (32%) showed tight dural attachment without any caval structure around the dural ring. The posteromedial portion of the carotid dural ring had no contact with any bony structure, and this distinct anatomical feature thus appear to facilitate the formation of the carotid cave. Furthermore, the availability of this potential space and the closely situated origin of the superior hypophyseal artery as well as the haemodynamic effect of the internal carotid artery may allow the development of the carotid cave aneurysm.

'Angiographic moyamoya' its definition, classification, and therapy

Are there any differences between probable Moyamoya disease and unilateral Moyamoya disease? What kinds of differences exist between definite and probable Moyamoya disease? Furthermore, according to the diagnostic criteria of Moyamoya disease, patients with systemic disorders and angiographic features similar to those of Moyamoya disease can not be diagnosed as Moyamoya disease. How should we call these? Such patients have been reported as 'Moyamoya syndrome,' 'quasi-Moyamoya disease', 'akin-Moyamoya disease'. etc. These variations of terminology including unilateral or probable Moyamoya disease have thus led to as state of confusion. In this study the previously reported cases in the literature were surveyed to clarify how these terms have been used and how we should use them correctly in the future. Since the diagnostic criteria of this disease are mainly based on angiographic findings, the term Moyamoya 'syndrome' should not be used. A unilateral involvement without any known cause should be called 'probable.' Because some systemic diseases commonly associated with Moyamoya disease might be genetically linked, it is better to avoid using such vague expressions as 'quasi', 'akin', or 'pseudo.' There might be a coexistence of two diseases. It is therefore better to simply state that the angiographic findings are similar to Moyamoya disease, or a systemic disease with 'angiographic Moyamoya' until the etiology of the Moyamoya disease is clarified.

Vitamin B6 suppresses growth and expression of albumin gene in a human hepatoma cell line HepG2

The effect of vitamin B6 on the growth of a human hepatoma cell line HepG2 in culture was studied. The growth of HepG2 cells and protein synthesis were almost completely inhibited in medium supplemented with 5 mM pyridoxine. Pyridoxal was as effective as pyridoxine, but pyridoxamine showed no inhibitory action. The growth inhibition of HepG2 cells by pyridoxine was accompanied by a marked inhibition of secretion of plasma proteins, particularly albumin. Northern blot analysis of albumin mRNA showed that pyridoxine caused a rapid decrease in the expression of albumin gene. The electron-microscopic examination of pyridoxine-treated HepG2 cells revealed a smoothing of nuclear membrane, a decrease in the number of nucleoli, and an appearance of aggregated heterochromatin structures. These morphological features are compatible with the depressed transcriptional activity in the pyridoxine-treated cells. The mechanism by which vitamin B6 exerts its inhibitory effect was discussed in terms of our recent finding that vitamin B6 modulates expression of albumin gene by inactivating tissue-specific DNA-binding proteins. Binding of pyridoxal phosphate with tissue-specific transcription factors may reduce the capacity of these factors to interact with the regulatory region of albumin gene, resulting in the inhibition of the gene expression.

Effect of varying amino acid levels on protein metabolism in nephrotic rats during total parenteral nutrition

In an attempt to determine appropriate diet in nephrotic syndrome, nephrotic rats, induced by puromycin aminonucleoside, were nourished by total parenteral nutrition fluid containing the same energy, but three different levels (1.65, 3.3, and 6.6%) of amino acids for 7 d. The fractional rate of total protein synthesis in the liver was determined by injecting a flooding dose of [3H]phenylalanine. The proportion of newly synthesized proteins retained and exported by the liver was estimated by injecting a tracer dose of [14C]leucine and then measuring the protein radioactivity remaining in the liver and present in the plasma after secretion was completed. Nephrotic animals synthesized more protein than control animals. Although the absolute synthesis rates of total protein in liver were increased with increasing amino acid administration, the absolute rates of synthesis of albumin were higher in the 3.3% group than in the other groups in nephrotic rats. However, kidney protein synthesis in nephrotic rats was higher in the 1.65% group than in the 3.3% group. Interestingly, the 3.3% group revealed the smallest urinary excretion of total protein and albumin. In addition, in the 3.3% group, plasma concentrations of total protein and albumin were higher, and plasma concentrations of total cholesterol and triglyceride were lower than in other groups. It was concluded that the 3.3% group, corresponding to a normal protein diet, has the greatest salutary effect on urinary protein excretion, followed by protein and lipid metabolism, in nephrotic rats. Not only protein intake but also the energy:protein ratio are important for diet therapy in nephrotic animals. The technique of total parenteral nutrition may be useful in defining the factors involved in glomerular permeability or permselectivity and intracellular protein metabolism.

Gene expression of CC chemokines in experimental crescentic glomerulonephritis (CGN)

CGN is a rapidly progressive glomerular disease. Monocytes/macrophages are frequently observed in glomeruli in cases of CGN and they are considered to play a crucial role in the pathogenesis of this disease. We described previously the glomerular expression of monocyte chemoattractant protein-1 (MCP-1), which is a potent chemoattractant for monocytes and a member of CC chemokine family, in an experimental model of CGN. In the present study we investigated the expression of mRNAs for other CC chemokines, namely, MCP-3, macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, RANTES and TCA3, all of which are chemotactic for monocytes, in the CGN model. First, we established a reverse transcriptase-polymerase chain reaction (RT-PCR) method by which mRNA for each of the CC chemokines could be amplified separately, and then we measured the levels of the expression of mRNAs for the chemokines in diseased glomeruli at several time points after induction of CGN. The mRNAs for all CC chemokines examined were expressed in glomeruli of rats with CGN. Moreover, induction of the gene expression of MIP-1alpha and MIP-1beta seemed to occur earlier than that of the others. CC chemokines may contribute to the recruitment and activation of monocytes in CGN, and each individual CC chemokine may play an overlapping but distinct role in the pathogenesis of this disease.

Production of monocyte chemoattractant protein-1 by cultured glomerular epithelial cells: inhibition by dexamethasone

Glomerular epithelial cells (GECs) have been shown to be one class of target cells in immunological and nonimmunological glomerular injury of glomerulonephritis, some cases of which are accompanied by infiltration of glomeruli by monocytes/macrophages. In this study we tested whether GECs in culture produce monocyte chemoattractant protein-1 (MCP-1), a potential molecule responsible for monocyte recruitment in inflammation, and whether the production is inhibited by glucocorticoid. GECs were obtained from outgrowth of rat glomeruli. Levels of MCP-1 mRNA and protein were determined by Northern blot analysis and ELISA, respectively. Northern blot analysis revealed the expression of MCP-1 mRNA in cytokine-treated GECs. The expression of MCP-1 mRNA was inhibited by dexamethasone. Quantitative analysis by ELISA confirmed the production of MCP-1 protein by GECs and the inhibitory effect of dexamethasone. These results indicate that cytokine-treated GECs produce and secrete MCP-1 and that the MCP-1 production is inhibited by dexamethasone. We suggest that MCP-1 produced by GECs may play a role in the recruitment of monocytes/macrophages in glomerulonephritis and that the therapeutic effect glucocorticoid on the disease might include the inhibition of the production of MCP-1.

Endocytosis of serum albumin in regenerating rat liver

Lysosomes, isolated from rat liver after 70% partial hepatectomy (PHX), were found, by Western blotting, to contain a considerable amount of serum albumin. The level of intralysosomal serum albumin after PHX showed biphasic patterns: it increased immediately after PHX, peaked at 30 min, rapidly declined within a few hours, rose again with a peak at 15 hr, and gradually declined thereafter. At 15 hr after PHX, the content of lysosomal proteins in the liver increased to twice the level of unoperated control, and the electron-microscopic observation of the isolated lysosomes revealed numerous large membrane-delimited structures with ground substances of variable electron opacities. The increase in the intralysosomal serum albumin at 30 min and 15 hr was accompanied by changes in the buoyant densities of endosomes in Percoll density gradients. At both time points, the density profiles of endosomes isolated from hepatectomized rats shifted to the denser direction, suggesting that PHX activates fusion and/or maturation of endosomes. Formaldehyde-treated bovine serum albumin is known to be taken up by the liver by receptor-mediated endocytosis. The uptake of the modified heterologous albumin was shown to be activated as early as 30 min after PHX. Both the uptake of serum albumin into lysosomes and the shift of buoyant density profile of endosomes after PHX were inhibited by the administration of adrenergic receptor antagonists, particularly by the alpha r-antagonist prazosin. Further, the concentration of catecholamines in rat serum, particularly that of norepinephrine, was found to increase immediately after PHX, relative to that in serum from sham-operated rats. These results suggest that the elevation of serum norepinephrine levels after PHX activates endocytosis and facilitates delivery of endocytosed serum albumin to lysosomes, where albumin is digested to yield amino acids for possible use in protein synthesis during liver regeneration.

Expression of monocyte chemoattractant protein-1 in experimental crescentic glomerulonephritis in rats

Crescentic glomerulonephritis (CGN) is a rapidly progressive glomerular disease that is usually associated with a poor prognosis. Monocytes/macrophages are frequently observed in glomeruli in cases of CGN, and they are considered to play a crucial role in the pathogenesis of this disease. In this study we analyzed the glomerular expression of monocyte chemoattractant protein-1 (MCP-1), a potent chemoattractant for monocytes, in an experimental model of CGN. A model of the disease was induced in the WKY strain of rats by intravenous injection of antiserum raised against glomerular basement membranes. Accumulation of monocytes/macrophages in glomeruli was observed 4 hours after the injection of antiserum. Northern blot analysis showed that the expression of mRNA for MCP-1 was enhanced within 4 hours, peaked on day 3--when it was 60 times that in the control--and then declined. Immunostaining with MCP-1-specific antibody revealed the expression of MCP-1 protein in the diseased glomeruli but not in control glomeruli. Quantitative analysis of glomerular MCP-1 protein by enzyme-linked immunosorbent assay revealed a level 46 times that in the control in reflecting the increase in mRNA for MCP-1. These results indicate that glomeruli of rats with CGN produce MCP-1, which may play an important role in the pathogenesis of glomerular inflammation and crescent formation in CGN.

Cloning and sequencing of cDNA encoding 4-aminobenzoate hydroxylase from Agaricus bisporus

A cDNA clone encoding 4-aminobenzoate hydroxylase (EC 1.14.13.27) has been isolated using a probe prepared by PCR on the basis of partially determined amino acid sequences of the enzyme. The cDNA contained 1380-base pair open reading frame encoding 460 amino acid residues (M(r) 50974), 14-base pair 5'-untranslated region and 123-base pair 3'-untranslated region including a poly(A) tail of 20 nucleotides. All of the partially determined amino acid sequences were shown to be included in the deduced amino acid sequence. Homology analyses showed that the two regions on the enzyme share other flavoproteins such as salicylate hydroxylase and p-hydroxybenzoate hydroxylase.

Detection of N-acetylgalactosaminyltransferase mRNA which determines expression of Sda blood group carbohydrate structure in human gastrointestinal mucosa and cancer

The Sda blood group carbohydrate structure, GalNAcbeta1-4[NeuAcalpha2-3]Galbeta1-4GlcNAc-R, is expressed on glycolipid and glycoprotein in human gastrointestinal mucosa. The expression of the Sda determinant dramatically decreases in cancer tissue. The activity of the beta1,4N-acetylgalactosaminyltransferase (Sda-GalNAcT), which transfers GalNAc to NeuAcalpha2-3Galbeta1-4Glc(NAc)-R, correlates with the expression of the Sda immuno-epitope. From the total RNA fraction of human gastric mucosa, we have amplified a cDNA segment by reverse-transcription-polymerase-chain reaction (RT-PCR), using primers designed according to the cDNA sequence of a murine beta1,4GalNAcT which synthesizes the Sda determinant. An RT-PCR product of 390 bp shared 85% nucleotide identity with the murine Sda-related beta1,4GalNAcT. This RT-PCR product hybridized to a transcript in mRNA prepared from human gastric mucosa. In RT-PCR using specific primers to this PCR product, Sda-GalNAcT mRNA was detected in all samples of normal stomach and small intestine examined and the majority of normal colonic specimens. Six out of nine cases of gastric cancer, and 9 out of 13 cases of colonic cancer failed to produce the target DNA. These results correlate with the beta1,4GalNAcT activity measured in the same samples. In conclusion, a segment of the cDNA for betal,4GalNAcT which determines expression of the Sda carbohydrate structure was obtained, and reduced transcription of this beta 1,4GalNAcT resulted in the disappearance of the Sda epitope in gastrointestinal cancer.

Vitamin B6 deficiency accelerates metabolic turnover of cystathionase in rat liver

Although most of cystathionase was found to exist as an inactive apoenzyme in the liver of vitamin B6-deficient rats, the concentrations of the immunoreactive enzyme protein were virtually the same for control and vitamin B6-deficient livers. Under vitamin B6 deficiency, however, the rate of synthesis of cystathionase, measured by incorporation of labeled amino acid into the immunoprecipitated enzyme, was increased severalfold due to an increased level of cystathionase mRNA. Western blot analysis of lysosomal proteins showed that the amount of cystathionase in the lysosomes from the liver of vitamin B6-deficient rats was also increased severalfold. This observation suggests that lysosomes specifically recognize the apocystathionase for sequestration in preference to the holoenzyme. The present study provides the molecular basis for dual roles of vitamin B6 in controlling the metabolic turnover of cystathionase; it regulates synthesis of the enzyme by modulating the expression of cystathionase gene, and it regulates degradation of the enzyme by different susceptibilities of apo- and holoenzymes to lysosomal proteolysis.

Jak3 expression in glomerular epithelia of IgA nephropathy (IgA-N) patients

Jak3 is a member of the Janus kinase family which plays an important role in cytokine signal transduction. Jak3 associates the gamma(c) chain of receptors for IL-2, IL-4, IL-7, IL-9 and IL-15, and is essential for the signal transduction of these cytokines. We have isolated Jak3 kinase from renal mesangial cells and demonstrated the constitutive expression of Jak3 in glomeruli in vivo. To investigate the physiological and pathological role of Jak3 in glomeruli, we prepared anti-Jak3 antibody and analysed the localization of Jak3 in glomeruli of renal biopsy samples from various nephritis patients and normal subjects. Among 61 nephritis patients and four normal subjects investigated in the present study, Jak3 was selectively localized to glomerular epithelia of IgA-N patients (14/34 cases) and focal glomerulosclerosis patients (1/5 cases), but not detected in minimal changes (n = 6), membranous glomerulonephropathy (n = 7), crescentic glomerulonephritis (n = 4), lupus nephritis patients (n = 5), and normal subjects (n = 4). The intense immunoreactivity for Jak3 is significantly associated with the decrease in creatinine clearance (81.5 +/- 10.4 ml/min versus 104.3 +/- 29.6 ml/min; P < 0.05, Student's t-test) and the increase in level of serum creatinine (1.13 +/- 0.33 mg/dl versus 0.75 +/- 0.23 mg/dl; P < 0.01, Student's t-test) in IgA-N patients. Furthermore, gamma(c) chain was concomitantly expressed with Jak3 in glomerular epithelia in vivo and in vitro, suggesting that signal transduction via gamma(c)-Jak3 cascade may be involved in the pathogenesis of glomerular injury of IgA-N. Taken together with the recent findings that IL-4-secreting T lymphocytes in affected glomeruli injure glomerular epithelium, the responsiveness of glomerular epithelium for IL-4 may be pathologically enhanced in IgA-N.