Developmental changes in Cl(-)-ATPase activity in rat brains

Developmental changes in brain Cl(-)-ATPase activity were examined using fetal, neonatal and adult rats. The Cl(-)-ATPase activity rapidly increased over 20 postnatal days to a level four-fold higher than that in an 18-day-old fetus. On Western blot analysis using an anti-Cl(-)-ATPase/pump 51 kDa subunit (ClP51) antibody, the amount of ClP51 protein increased in parallel with Cl(-)-ATPase activity. Immunohistochemistry using the same antibody showed Cl(-)-ATPase-like immunoreactivity on the cell membranes of neurons such as cerebral and hippocampal pyramidal cells and cerebellar Purkinje cells, where the immunoreactivity increased with developmental changes in the size and shape of the neurons. These findings suggest that neuronal Cl(-)-ATPase activity markedly increases during early postnatal development with an increase in the amount of Cl(-)-ATPase protein, which may support the formation of inwardly directed neuronal Cl(-) gradients.

An evaluation of elastomeric impression materials based on surface compressive strength

The setting times of seven commercially available elastomeric impression materials were determined using Wilson's reciprocating rheometer at temperatures 23 +/- 0.5 or 32 +/- 0.5 degrees C. The surface compressive strength and depression of these materials after setting time were measured using a rheometer (Fudoh). Each material was mixed according to the mixing proportion (base/accelerator or catalyst ratio) recommended by the manufacturer. The surface compressive strength and the depression of each material were measured by using a method which pressed the material to the edge of a sensitive rod (2.0 mm in diameter) connected to a load cell. In the case of silicone impression materials (additional type) at a temperature of 23 +/- 0.5 degrees C, the surface compressive strength and the depression of these materials were extremely stable after the setting time. However, the surface compressive strength of other materials except additional type materials increased markedly after setting time and the depression corresponding to the surface compressive strength decreased. These increased largely with the increase, in pressing speed to the sensitive rod. At 450 s from the setting time of all materials, there was an adequate correlation (r = 0.84) between measured values and theoretical values derived using the theory of elasticity.

Discoid lupus erythematosus developing in areas where fragments of windshield glass had become embedded in the skin

We observed a 26-year-old female patient with discoid lupus erythematosus on her left cheek skin, where fine fragments of windshield glass had been embedded in an automobile accident 8 years previously. She gradually developed general fatigue, morning stiffness of fingers and anti-nuclear antibody. As an etio-pathogenesis of this patient, we speculate that a long exposure to quartz (silica) could give rise to discoid lupus erythematosus in only local damaged areas and at the same time induce systemic immunological changes in some genetically restricted persons; such as production of anti-nuclear antibody. Silica has multi-potential biological effects, especially on immunological functions.

N-acyl-L-homoserine lactone-mediated regulation of the lip secretion system in Serratia liquefaciens MG1

The analysis of Serratia liquefaciens MG1 'luxAB insertion mutants that are responsive to N-butanoyl-L-homoserine lactone revealed that expression of lipB is controlled by the swr quorum-sensing system. LipB is part of the Lip exporter, a type I secretion system, which is responsible for the secretion of extracellular lipase, metalloprotease, and S-layer protein.

Isolation and characterization of Na+/Ca2+ exchanger gene and splicing isoforms in mice

The Na+/Ca2+ exchanger gene NCX1 is ubiquitously expressed in mammalian tissues, and encodes several isoforms through alternative RNA splicing. In this report, we describe the gene structure that gives rise to the multiple isoforms, and the tissue-specific expression of these isoforms in mice. The mouse NCX1 gene contains a cluster of six exons (A, B, C, D, E, and F) which encode a variable region in the large intracellular loop of the protein, as previously reported in rabbits and humans. Using reverse transcription-polymerase chain reaction (RT-PCR), expression of the isoforms was examined in several tissues. We also identified a novel splice variant, which originate from exons A, C, D, and F. These findings provide new insights into the significance of the large repertoire of NCX1 isoforms.

Expression of TMEFF1 mRNA in the mouse central nervous system: precise examination and comparative studies of TMEFF1 and TMEFF2

TMEFF1 and TMEFF2 are putative transmembrane proteins comprised of one epidermal growth factor (EGF)-like domain and two follistatin-like domains. Both TMEFF1 and TMEFF2 are predominantly expressed in the brain. We previously demonstrated that recombinant TMEFF2 protein can promote survival of neurons in primary culture and determined expression sites of TMEFF2 mRNA in the mouse central nervous system. To extend our understanding of TMEFF protein functions, we compared precise sites of expression of TMEFF1 and TMEFF2 mRNA using in situ hybridization analysis. Although both TMEFF genes are widely expressed in the brain, they exhibit different patterns of expression. TMEFF1 showed comparatively higher signals in the pyramidal cells of fifth layer of the cerebral neocortex, CA3, CA1 and subiculum regions of the hippocampus, locus coeruleus, and dentate cerebellar nucleus. In contrast, TMEFF2 is highly expressed in the medial habenular, CA2, CA3 and dentate gyrus region of the hippocampus, corpus callosum, cerebellar cortex and cranial nerve nuclei (III, IV, VII, X, XII). The results presented here indicate that expression of TMEFF1 and TMEFF2 are regulated differently and that they play region-specific roles in the central nervous system.

Human Ca2+/calmodulin-dependent phosphodiesterase PDE1A: novel splice variants, their specific expression, genomic organization, and chromosomal localization

We report here the identification of novel human PDE1A splice variants, their tissue distribution patterns, genomic structure, and chromosomal localization of the gene. We identified one N-terminus (N3) and one C-terminus (C3) by cDNA library screening and dbEST database search. These N- and C-termini, including the reported N-termini (N1 and N2) and C-termini (C1 and C2), combined to generate nine different PDE1A cDNAs. N1 and N2 are similar to the 5' ends of the bovine PDE1A proteins of 61 kDa and 59 kDa, respectively, and C1 and C2 are the 3' ends of the reported human PDE1A variants. The results of PCR and Southern blot analysis show that nine PDE1A splice variants exhibit distinctive tissue distribution patterns by the difference of the N-terminus. PDE1As with N2 were widely expressed in various tissues, mainly in the kidney, liver, and pancreas. On the other hand, PDE1As with N1 and N3 were particularly expressed at a high level in the brain and testis, respectively. These findings suggest that the distinct expression patterns among PDE1A variants depend on the several promoters situated upstream of exons encoding 5' ends of the variants. The PDE1A gene spans over 120 kb of genomic DNA, and consists of at least 17 exons and 16 introns. The PDE1A gene was located on human chromosome 2q32 by fluorescent in situ hybridization analysis.

Genomic organization of the human phosphodiesterase PDE11A gene. Evolutionary relatedness with other PDEs containing GAF domains

PDE11A is a dual-substrate, cAMP and cGMP, cyclic nucleotide phosphodiesterase (PDE). Presently four unique variants carrying distinct GAF sequences in the N-terminal region have been identified. While human PDE11A3 and PDE11A4 are known to be specifically expressed in testis and prostate, respectively, PDE11A1 was mainly detected in skeletal muscle. The human PDE11A gene was investigated and revealed to span > 300 kb, contain 23 exons and be mapped on chromosome 2q31. The transcription start sites of PDE11A1, PDE11A3 and PDE11A4 were determined, and the promoter sequences were revealed. Although 5' flanking genomic regions of PDE11A1 and PDE11A3 had a consensus TATA motif, that of PDE11A4 was a TATA-less but contained CCAAT box and Sp1-binding sequence. Interestingly, we found that the exon 2 sequence for N-terminal region of PDE11A3 encoded an N-terminal sequence of the cytochrome c pseudogene in an alternate reading frame, and that C-terminal region of the cytochrome c pseudogene in intron 2 was disrupted by the insertion of Alu repetitive sequence. Furthermore, we examined the exon-intron organization of the PDE2A gene and compared the exon organization among GAF-PDE family. The exon organization of the PDE11A catalytic domain was very similar to those of PDE5A and PDE6B. However, other GAF-PDEs, PDE2A and PDE10A, displayed different exon organization from PDE11A although these three PDEs are similar in their amino-acid sequences to each other. The findings suggested that PDE11A has a common ancestral gene with PDE5A and PDE6s, whereas PDE2A and PDE10A are generated separately from these three GAF-PDEs.

[Special categories of elderly patients with intractable neurological diseases (NANBYO) in Toyama, Japan]

The purpose of this study was to elucidate special categories of elderly patients with intractable neurological diseases (NANBYO) in Toyama, Japan. This goal was accomplished through comparisons of data gathered in 1991 and 1997. Forty-eight (20 males, 28 females) with such diseases were recruited for the study and agreed to be interviewed. The surveys were performed by three public health center nurses. The same questionnaire was used in both years. The surveys show that the number of jobless patients and those who needed total support increased by approximately 20% from 1991 to 1997. In addition, it appears that the ratio of hospitalized patients and those who needed medical equipment installed at home increased considerably. The number of patients with caregivers increased by approximately 30%. As the caregivers got older, it was observed that the patients became more anxious about their health condition. Also, in both years, both patients and caregivers showed the highest concern about a sudden change in the patients' conditions. In conclusion, an assessment of patient and family needs is important for the development of a community health care system. It is also essential for all the parties in the field of health, medicine, and welfare, as well as volunteer groups, to have a good understanding of each other's services and to have a cooperative relationship coordinated by health centers through discussion of each individual case.

Targeted disruption of Na+/Ca2+ exchanger gene leads to cardiomyocyte apoptosis and defects in heartbeat

Ca(2+), which enters cardiac myocytes through voltage-dependent Ca(2+) channels during excitation, is extruded from myocytes primarily by the Na(+)/Ca(2+) exchanger (NCX1) during relaxation. The increase in intracellular Ca(2+) concentration in myocytes by digitalis treatment and after ischemia/reperfusion is also thought to result from the reverse mode of the Na(+)/Ca(2+) exchange mechanism. However, the precise roles of the NCX1 are still unclear because of the lack of its specific inhibitors. We generated Ncx1-deficient mice by gene targeting to determine the in vivo function of the exchanger. Homozygous Ncx1-deficient mice died between embryonic days 9 and 10. Their hearts did not beat, and cardiac myocytes showed apoptosis. No forward mode or reverse mode of the Na(+)/Ca(2+) exchange activity was detected in null mutant hearts. The Na(+)-dependent Ca(2+) exchange activity as well as protein content of NCX1 were decreased by approximately 50% in the heart, kidney, aorta, and smooth muscle cells of the heterozygous mice, and tension development of the aortic ring in Na(+)-free solution was markedly impaired in heterozygous mice. These findings suggest that NCX1 is required for heartbeats and survival of cardiac myocytes in embryos and plays critical roles in Na(+)-dependent Ca(2+) handling in the heart and aorta.

Characterization and effects of methyl-2- (4-aminophenyl)-1, 2-dihydro-1-oxo-7- (2-pyridinylmethoxy)-4-(3,4, 5-trimethoxyphenyl)-3-isoquinoline carboxylate sulfate (T-1032), a novel potent inhibitor of cGMP-binding cGMP-specific phosphodiesterase (PDE5)

An isoquinolone derivative, methyl-2-(4-aminophenyl)-1, 2-dihydro-1-oxo-7-(2-pyridinylmethoxy)-4-(3,4, 5-trimethoxyphenyl)-3-isoquinoline carboxylate sulfate (T-1032), was found to be a novel potent inhibitor of cyclic GMP (cGMP)-binding cGMP-specific phosphodiesterase (PDE5). We investigated the inhibitory effects of T-1032 on six PDE isozymes isolated from canine tissues. T-1032 specifically inhibited the hydrolysis of cGMP by PDE5 partially purified from canine lung, at a low concentration (IC(50) = 1.0 nM, K(i) = 1.2 nM), in a competitive manner. In contrast, the IC(50) values of T-1032 for PDE1, PDE2, PDE3, and PDE4 were more than 1 microM. T-1032 also inhibited PDE6 from canine retina with an IC(50) of 28 nM, which is of the same order of magnitude as the IC(50) of sildenafil. cGMP hydrolytic activities of two alternative splice variants of canine PDE5 expressed in COS-7 cells were inhibited by this compound to a similar extent. T-1032 increased the intracellular concentration of cGMP in cultured rat vascular smooth muscle cells in the presence and absence of C-type natriuretic peptide, an activator of membrane-bound guanylate cyclase, whereas the compound did not change cyclic AMP levels. These data indicated that T-1032, which belongs to a new structural class of PDE5 inhibitors, is a potent and selective PDE5 inhibitor. This compound may be useful in pharmacological studies to examine the role of a cGMP/PDE5 pathway in tissues.

Isolation and characterization of two novel phosphodiesterase PDE11A variants showing unique structure and tissue-specific expression

cDNAs encoding a novel phosphodiesterase, phosphodiesterase 11A (PDE11A), were isolated by a combination of reverse transcriptase-polymerase chain reaction using degenerate oligonucleotide primers and rapid amplification of cDNA ends. Their catalytic domain was identical to that of PDE11A1 (490 amino acids) reported during the course of this study. However, the cDNAs we isolated had N termini distinct from PDE11A1, indicating two novel N-terminal variants of PDE11A. PDE11A3 cDNA encoded a 684-amino acid protein including one complete and one incomplete GAF domain in the N-terminal region. PDE11A4 was composed of 934 amino acids including two complete GAF domains and shared 630 C-terminal amino acids with PDE11A3 but had a distinct N terminus containing the putative phosphorylation sites for cAMP- and cGMP-dependent protein kinases. PDE11A3 transcripts were specifically expressed in testis, whereas PDE11A4 transcripts were particularly abundant in prostate. Recombinant PDE11A4 expressed in COS-7 cells hydrolyzed cAMP and cGMP with K(m) values of 3.0 and 1.4 microm, respectively, and the V(max) value with cAMP was almost twice that with cGMP. Although PDE11A3 showed the same K(m) values as PDE11A4, the relative V(max) values of PDE11A3 were approximately one-sixth of those of PDE11A4. PDE11A4, but not PDE11A3, was phosphorylated by both cAMP- and cGMP-dependent protein kinases in vitro. Thus, the PDE11A gene undergoes tissue-specific alternative splicing that generates structurally and functionally distinct gene products.

The human phosphodiesterase PDE10A gene genomic organization and evolutionary relatedness with other PDEs containing GAF domains

PDE10A is a cyclic nucleotide phosphodiesterase (PDE) exhibiting properties of a cAMP PDE and a cAMP-inhibited cGMP PDE. The transcripts are specifically expressed in the striatum. The human gene encoding PDE10A was cloned and investigated. The PDE10A gene spanned > 200 kb and contained 24 exons. The exon-intron organization of PDE10A was different from those of PDE5A and PDE6B, although these three PDEs include two GAF domains and have similar amino-acid sequences. The promoter sequence of PDE10A was highly GC-rich and did not contain a TATA motif and a CAAT box, suggesting it is a housekeeping gene. In Caenorhabditis elegans, the C32E12.2 gene encoding a probable PDE that is 48% identical to the human PDE10A protein showed similar exon organization to PDE10A but not PDE5A and PDE6B. This, together with the phylogenic tree analysis, suggested that the ancestral gene for PDE10A existed in a lower organism such as C. elegans.

Functional characterization of the HasA(PF) hemophore and its truncated and chimeric variants: determination of a region involved in binding to the hemophore receptor

Hemophores are secreted by several gram-negative bacteria (Serratia marcescens, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Yersinia pestis) and form a family of homologous proteins. Unlike the S. marcescens hemophore (HasA(SM)), the P. fluorescens hemophore HasA(PF) has an additional region of 12 residues located immediately upstream from the C-terminal secretion signal. We show that HasA(PF) undergoes a C-terminal cleavage which removes the last 21 residues when secreted from P. fluorescens and that only the processed form is able to deliver heme to the S. marcescens outer membrane hemophore-specific receptor, HasR(SM). Functional analysis of variants including those with an internal deletion of the extra C-terminal domain show that the secretion signal does not inhibit the biological activity, whereas the 12-amino-acid region located upstream does. This extra domain may inhibit the interaction of the hemophore with HasR(SM). To localize the hemophore regions involved in binding to HasR, chimeric HasA(PF)-HasA(SM) proteins were tested for biological activity. We show that residues 153 to 180 of HasA(PF) are necessary for its interaction with the receptor.

Immunohistochemical demonstration of Cl- pump in type A intercalated cells of rat kidney

In order to demonstrate the localization of an ethacrynic acid-sensitive Cl- pump in the rat kidney, immunohistochemical analysis was performed using an anti-Cl- pump antibody raised against rat brain Cl- pump protein with confocal laser scanning microscopy. The antibodies against Na+,K+-ATPase, aquaporin 2 and a type B intercalated cell marker, 43-kDa protein, were also used for comparison. Anti-Cl- pump antibody recognized a 51-kDa renal protein of the same size as that in the brain on Western blots. Cl- -pump-like immunoreactivity was observed on the basolateral membranes of 42+/-3% of cortical collecting duct (CCD) cells and of 38+/-1% of outer medullar collecting duct (OMCD) cells. Such immunoreactivity in CCD was sometimes co-localized with Na+,K+-ATPase, but in OMCD, the Cl- pump-like immunoreactivity co-existed with neither Na+,K+-ATPase, aquaporin 2 nor the type B intercalated cell marker 43-kDa protein. Thus, the Cl- pump was demonstrated to be localized on the basolateral membranes of type A intercalated cells of cortical and medullary collecting ducts in the rat kidney.

Effects of thyroplasty type I on vocal fold vibration

OBJECTIVE

To ascertain effects of medialization thyroplasty on vocal fold vibration in glottic incompetence dysphonia.

STUDY DESIGN

Quantitative videostroboscopic glottic measurements and vocal function study were perioperatively undertaken in 20 patients undergoing Isshiki's thyroplasty type I.

METHODS

In digitized images, the glottal area, glottal width, posterior glottal width, and amplitude over an entire glottal cycle were measured and normalized by membranous vocal fold length. The ratio of closed phase to total phase of vibratory cycle was calculated from the data of the glottal area and the glottal width at the middle point of the membranous vocal fold. Well-accepted acoustic, aerodynamic, and perceptual measures analyzed vocal function.

RESULTS

Glottal area and glottal width were reduced after surgery. While preoperative closure of glottal area was incomplete in all 20 patients, incomplete closure was obtained in 16 patients after surgery. In these 16 patients, closure of glottal width at the middle point of the membranous vocal fold was complete, whereas a posterior glottal gap remained in 14 patients. Closed phase over one cycle of glottal width waveform and amplitude of vocal fold vibration were increased after surgery. Glottal area, glottal width, posterior glottal width, and closed phase over one cycle of glottal width waveform correlated with vocal function measures.

CONCLUSIONS

Thyroplasty type I reduces a glottal gap and increases closed phase over one cycle and amplitude of vocal fold vibration, although a posterior glottal gap remains. With the improved glottic vibration, thyroplasty type I provides more efficient phonation in patients with glottic incompetence dysphonia.

Identification of human PDE7B, a cAMP-specific phosphodiesterase

We isolated a human cAMP-specific phosphodiesterase (PDE7B) cDNA from human caudate nucleus. The human PDE7B was composed of 450 amino acid residues with a molecular mass of 51,835 Da. The deduced amino acid sequence of human PDE7B was 64.1% identical to that of human PDE7A (67.1% identity in the catalytic region). Northern blot analysis demonstrated that PDE7B transcripts were abundantly expressed in the putamen, caudate nucleus, and heart followed by skeletal muscle, pancreas, and occipital pole. Recombinant PDE7B expressed in transfected COS-7 cells had a low cAMP K(m) value of 0. 13 microM, which is similar to the K(m) value of recombinant human PDE7A expressed in transfected COS-7 cells. Interestingly, the relative V(max) value of recombinant PDE7B was half to one-third of recombinant PDE7A. The PDE7B activity was inhibited by dipyridamole and SCH51866, with IC(50) values of 1.1 microM and 1.5 microM, respectively. Thus, the PDE7B exhibited unique tissue distribution in humans and kinetic profiles. Human PDE7B showed the lowest K(m) values compared to the other cAMP-hydrolyzing PDEs which have been reported to be expressed in the brain. Therefore, human PDE7B may be involved in the control of cAMP-mediated neural activity and cAMP metabolism in the brain.

Apolipoprotein E, methylenetetrahydrofolate reductase (MTHFR) mutation and the risk of senile dementia--an epidemiological study using the polymerase chain reaction (PCR) method

We examined apolipoprotein E (Apo E) polymorphism and methylenetetrahydrofolate reductase (MTHFR) 677 C to T mutation by using the polymerase chain reaction (PCR) method in 100 elderly Japanese aged 60 or more, and assessed whether these genetic factors are associated with an increased risk for the clinical phenotypes of senile dementia, Alzheimer's disease (AD) and vascular dementia (VD) by cross-sectional survey. It was found that the Apo E epsilon 4 allele were associated with an increased prevalence of AD as previously reported. Although, it was not strongly related to the severity of senile dementia, a weak association between the ApoE genotype and the severity of dementia was suggested. The proportion of patients with senile dementia was higher in the group of carriers of MTHFR mutation than in the group of noncarriers. Furthermore, the proportion of male patients with senile dementia was higher in the group of homozygous for the mutation (+/+) than the group without the mutation (-/-). Notably in VD patients, 5 of 7 males had the +/+ genotype. The results suggest that the ApoE epsilon 4 genotype and the MTHFR mutation are associated with the clinical phenotype and the clinical onset of senile dementia.

Immunohistochemical localization of cGMP-binding cGMP-specific phosphodiesterase (PDE5) in rat tissues

We raised a polyclonal antibody against maltose binding protein fusion human cGMP-binding, cGMP-specific phosphodiesterase (PDE5) produced in E. coli. This antibody immunoreacted specifically with recombinant human and rat PDE5 proteins expressed in transfected COS-7 cells and with a native form of PDE5 in extracts of rat platelets, lung, and cerebellum. Immunohistochemical analysis showed that the anti-PDE5 antibody detected immunoactive materials in Purkinje cell layers of the cerebellum, proximal renal tubules, collecting renal ducts, and epithelial cells of pancreatic ducts in rats. Reverse transcriptase-polymerase chain reaction analysis demonstrated that PDE5 transcripts are also present in rat cerebellum, kidney, and pancreas. Here we described a cell-specific localization of PDE5 in various rat tissues, suggesting the possibility of the presence of a cGMP/PDE5 pathway in these tissues.

The chloride channel ClC-2 contributes to the inwardly rectifying Cl- conductance in cultured porcine choroid plexus epithelial cells

1. The contribution of ClC-2 protein to the inwardly rectifying Cl- conductance in cultured porcine choroid plexus epithelial cells was investigated using Western analysis and whole-cell current recordings. 2. Inwardly rectifying currents were elicited by hyperpolarizing voltage at a potential more negative than -50 mV in the presence of intracellular protein kinase A (PKA). The relative halide selectivity estimated from the shift in the reversal potential (Erev) was I- > Br- > Cl- > F-. 3. Extracellular vasoactive intestinal peptide (VIP) activated the same currents in a dose-dependent manner with a half-maximal concentration of 167.3 nM. H-89 (a PKA inhibitor) interfered with the current activation by VIP. 4. The Cl- channel was inhibited by external Cd2+, Ba2+or H+, but only weakly inhibited by known Cl- channel blockers including glibenclamide, NPPB, DIDS and anthracene-9-carboxylic acid (9AC). 5. A specific antibody to ClC-2 detected a 79 kDa protein in porcine choroid plexus cells, which was reduced in cells treated with antisense oligodeoxynucleotide for ClC-2. Both PKA and VIP failed to activate the inwardly rectifying Cl- currents in cells transfected with the antisense oligodeoxynucleotide, while they activated the currents in cells transfected with GFP alone or the control oligodeoxynucleotide randomized from antisense oligonucleotide. 6. It is concluded that ClC-2 protein contributes to the inwardly rectifying Cl- conductance in porcine choroid plexus epithelial cells.

Binding and phosphorylation of a novel male germ cell-specific cGMP-dependent protein kinase-anchoring protein by cGMP-dependent protein kinase Ialpha

cGMP-dependent protein kinase (cGK) is a major cellular receptor of cGMP and plays important roles in cGMP-dependent signal transduction pathways. To isolate the components of the cGMP/cGK signaling pathway such as substrates and regulatory proteins of cGK, we employed the yeast two-hybrid system using cGK-Ialpha as a bait and isolated a novel male germ cell-specific 42-kDa protein, GKAP42 (42-kDa cGMP-dependent protein kinase anchoring protein). Although the N-terminal region (amino acids 1-66) of cGK-Ialpha is sufficient for the association with GKAP42, GKAP42 could not interact with cGK-Ibeta, cGK-II, or cAMP-dependent protein kinase. GKAP42 mRNA is specifically expressed in testis, where it is restricted to the spermatocytes and early round spermatids. Endogenous cGK-I is co-immunoprecipitated with anti-GKAP42 antibody from mouse testis tissue, suggesting that cGK-I physiologically interacts with GKAP42. Immunocytochemical observations revealed that GKAP42 is localized to the Golgi complex and that cGK-Ialpha is co-localized to the Golgi complex when coexpressed with GKAP42. Although both cGK-Ialpha and -Ibeta, but not cAMP-dependent protein kinase, phosphorylated GKAP42 in vitro, GKAP42 was a good substrate only for cGK-Ialpha in intact cells, suggesting that the association with kinase protein is required for the phosphorylation in vivo. Finally, we demonstrated that the kinase-deficient mutant of cGK-Ialpha stably associates with GKAP42 and that binding of cGMP to cGK-Ialpha facilitates their release from GKAP42. These findings suggest that GKAP42 functions as an anchoring protein for cGK-Ialpha and that cGK-Ialpha may participate in germ cell development through phosphorylation of Golgi-associated proteins such as GKAP42.

[Sarcoidosis differentially diagnosed from mediastinal tumor by thoracoscopic biopsy]

A 46-year-old man presented with swallowing difficulty and dyspnea when in the supine position. Chest X-ray and computed tomographic (CT) films disclosed left pleural effusion and a tumor shadow extending invasively from superior to anterior mediastinum around the heart and large arteries. These observations called for a differential diagnosis from malignant lymphoma, invasive thymoma, and small cell carcinoma. Bronchofiberscopy and percutaneous tumor biopsy were performed, but the findings were inconclusive. Thoracoscopic biopsy yielded a diagnosis of sarcoidosis. No extrathoracic lesions were detected. Corticosteroid therapy (30 mg/day of prednisolone) was started. After 6 months of treatment (7.5 mg/day of prednisolone), the tumor shadow was reduced in size and the patient's swallowing difficulty and dyspnea subsided. This was a rare case of sarcoidosis extending invasively around the heart and large arteries, and that needed to be differentiated from mediastinal tumor. Thoracoscopic biopsy should be actively enlisted as a diagnostic procedure in difficult cases of this kind.