Altered gene expression of natriuretic peptide receptor subtypes in the kidney of stroke-prone spontaneously hypertensive rats

1. To elucidate the physiological and pathophysiological role of the natriuretic peptide system in the progression of hypertensive renal disease, we examined the gene expression of natriuretic peptide receptor subtypes, guanylate cyclase-A (GC-A), guanylate cyclase-B (GC-B) and clearance receptor (C receptor), in the kidney of stroke-prone spontaneously hypertensive rats (SHRSP) at 8 and 20 weeks of age, and compared them with their gene expression in age-matched Wistar-Kyoto (WKY) rats. 2. Northern blot analyses revealed that messages for three natriuretic peptide receptor subtypes were expressed in the kidney, and their expressions were higher in the glomeruli than in the whole kidney in each strain. 3. In 20 week old rats with established hypertension, the glomerular concentration of GC-A mRNA was significantly higher in SHRSP than in WKY. The concentrations of GC-B and C receptor mRNA in the glomeruli tended to increase and decrease, respectively, but they were not statistically significant in SHRSP. 4. In 8 week old rats, the glomerular concentrations of GC-A, GC-B and C receptor mRNA were not significantly different between SHRSP and WKY. 5. This study demonstrates that in the progression of hypertension, the expression of GC-A, which mediates biological actions of natriuretic peptides, is enhanced in the kidney of SHRSP compared to that of WKY. Together with the augmented secretion of the ligands previously revealed, altered expression of natriuretic peptide receptor subtypes in SHRSP may have a deterrent role in the development of hypertension and its renal complications.

Preparation of a monoclonal antibody against mouse brain natriuretic peptide (BNP) and tissue distribution of BNP in mice

1. In order to explore the significance of brain natriuretic peptide (BNP), a cardiac hormone secreted from the ventricle, in mice, we prepared a monoclonal antibody against mouse BNP (mBNP) and established a specific radioimmunoassay (RIA) for mBNP. 2. A monoclonal antibody, KY-mBNP-I, was prepared by the fusion of mouse myeloma cells X63-Ag8.653 with spleen cells of the BALB/c mouse immunized with synthetic mBNP[108-121] conjugated to bovine thyroglobulin. KY-mBNP-I belonged to an IgG2a subclass and showed a high affinity for mBNP (Ka = 1.8 x 10(11) mol/L-1). 3. The RIA established that using KY-mBNP-I was highly sensitive and specific for mBNP, with an IC50 value of 3 fmol/tube and cross-reactivities of less than 0.003% with related natriuretic peptides. mBNP-like immunoreactivity (mBNP-LI) was detected in the mouse atrium (0.35 +/- 0.02 nmol/g), ventricle (20.5 +/- 0.5 pmol/g) and kidney (0.50 +/- 0.05 pmol/g), but not in other tissues including brain. 4. Gel filtration analysis revealed that the major component of tissue mBNP-LI was co-eluted with synthetic mBNP[77-121], a 45-amino acid mature peptide. 5. The monoclonal antibody and RIA for mBNP established here will provide useful tools to investigate the functional significance of BNP in mice, coupled with the genetic engineering approach.

Augmented expression of the endothelin-A receptor gene in cultured mesangial cells from stroke-prone spontaneously hypertensive rats

1. To elucidate the role of endothelin (ET) receptor in hypertension, we studied the expression of the ET-A receptor (ET-AR) gene and the ET-B receptor (ET-BR) gene in cultured mesangial cells isolated from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto (WKY) rats. 2. The mesangial cells from both SHRSP and WKY expressed ET-AR predominantly. The level of the ET-AR mRNA in mesangial cells from SHRSP was 5-fold higher than that in the cells from WKY. The ET-BR mRNA in the mesangial cells from both strains was hardly detectable by northern blot analysis. 3. These results demonstrate that the expression of the ET-AR gene was markedly augmented in mesangial cells from SHRSP.

Decreased expression of the very low density lipoprotein receptor mRNA in the cardiac ventricle of spontaneously hypertensive rats

1. To elucidate the functional implication of very low density lipoprotein (VLDL) receptor, we studied the gene expression of VLDL receptor in rats. The VLDL receptor mRNA was highly expressed in the cardiac ventricle and skeletal muscle. Intermediate amounts of VLDL receptor mRNA were detected in adipose tissue, adrenal gland, brain and lung. Thus the tissue distribution of VLDL receptor mRNA in rats was similar to that reported previously in rabbits. 2. We studied the gene expression of the VLDL receptor in the heart of stroke-prone spontaneously hypertensive rats (SHRSP), an animal model for hypertension-induced cardiac hypertrophy. RNase protection assay showed that the level of ventricular VLDL receptor mRNA was already decreased to one half when hypertension was not fully developed, and further diminished to one fifth when cardiac hypertrophy was established. 3. It is reported that energy utilization in SHRSP hypertrophied myocardium is impaired. Our results suggest that inactive fatty acid metabolism in the ventricle of SHRSP is related to the lowered expression of the VLDL receptor which is postulated as a gate for triglyceride-rich lipoprotein particle.

Structural organization and chromosomal assignment of the human obese gene

The obese (ob) gene has been identified through a positional cloning approach; the mutation of this gene causes marked hereditary obesity and diabetes mellitus in mice. We report here the isolation and characterization of the human ob gene. Southern blot analysis demonstrated a single copy of the ob gene in the human genome. The human ob gene spanned approximately 20 kilobases (kb) and contained three exons separated by two introns. The first intron, approximately 10.6 kb in size, occurred in the 5'-untranslated region, 29 base pair (bp) upstream of the ATG start codon. The second intron of 2.3 kb in size was located at glutamine +49. By rapid amplification of 5'-cDNA ends, the transcription initiation sites were mapped 54-57 bp upstream of the ATG start codon. The 172-bp 5'-flanking region of the human ob gene contained a TATA box-like sequence and several cis-acting regulatory elements (three copies of GC boxes, an AP-2-binding site, and a CCAAT/enhancer-binding protein-binding site). By the fluorescence in situ hybridization technique, the ob gene was assigned to human chromosome 7q31.3. This study should establish the genetic basis for ob gene research in humans, thereby leading to the better understanding of the molecular mechanisms underlying the ob gene.

Augmented expression of the obese gene in the adipose tissue from rats fed high-fat diet

Expression of the obese (ob) gene is augmented in the adipose tissue in several rodent models of genetic obesity. In the present study, we examined the ob gene expression in a rodent model of acquired obesity obtained by pure overfeeding of normal rats. Male Sprague-Dawley rats at 8 weeks of age were fed standard diet or high-fat diet. Rats fed high-fat diet developed moderate degree of obesity, hyperglycemia, and hyperlipidemia as compared with rats fed standard diet. Northern blot analysis revealed that the ob gene is expressed abundantly in the adipose tissue obtained from the epididymal, mesenteric, subcutaneous, retroperitoneal, and interscapular fat pads in rats fed standard diet. Expression of the ob gene was augmented in all the adipose tissue examined in rats fed high-fat diet. The present study demonstrates that the ob gene expression is augmented in the adipose tissue in diet-induced obesity, thereby suggesting the pathophysiologic roles of the ob gene in acquired obesity.

Molecular cloning and expression of multiple isoforms of human prostaglandin E receptor EP3 subtype generated by alternative messenger RNA splicing: multiple second messenger systems and tissue-specific distributions

Five distinct cDNA clones encoding four different isoforms of human prostaglandin (PG) E receptor EP3 subtype were isolated from a human kidney cDNA library. Two cDNA clones differed only in their 3'-untranslated regions. The four isoforms, tentatively named EP3-I, EP3-II, EP3-III, and EP3-IV, which were generated by alternative mRNA splicing, had identical amino acid sequences except for their different carboxyl-terminal tails. Transfection experiments revealed that all the four isoforms show high binding affinities to PGE2, PGE1, and M&B28767, an EP3-specific agonist, whereas their downstream signaling pathways are divergent. M&B28767 increased cAMP concentrations in cells expressing EP3-II and EP3-IV, whereas it inhibited forskolin-induced cAMP accumulations in cells expressing all EP3 isoforms. M&B28767 also stimulated phosphoinositide turnover in cells expressing EP3-I and EP3-II. Northern blot analysis revealed that the EP3 gene is expressed in a wide variety of human tissues. The human EP3 mRNA was present most abundantly in the kidney, pancreas, and uterus. A substantial expression was also detected in the heart, liver, skeletal muscle, small intestine, colon, prostate, ovary, and testis. Furthermore, reverse transcription-polymerase chain reaction analysis demonstrated tissue-specific expressions of the five different EP3 mRNA species. The present study suggests the presence of the multiple systems of PGE2/EP3 isoforms and leads to the better understanding of its physiological and pathophysiological implications in humans.

Comparative study of bone marrow induced by purified BMP and recombinant human BMP-2

Into a calf muscle pouch in Wistar rats, 50 micrograms purified bone morphogenetic protein (pBMP) or 50 micrograms recombinant human bone morphogenetic protein-2 (rhBMP-2) was implanted using atelopeptide type I collagen solution (CL) as a carrier. Three weeks later bone and bone marrow were induced in both groups. These induced bone and bone marrow were studied histologically. In the pBMP+CL group (n = 5), rich bone matrix and little bone marrow were observed. There was no fatty marrow or angioid tissue observed. In the rhBMP-2+CL group (n = 5), bone matrix and rich marrow including fatty marrow and angioid tissue were observed around and among the bony trabeculae. It was suggested that a "self-supporting bone organ" was induced.

[Clinical aspects and types of Sjögren's syndrome]

Sjögren's syndrome (SS) is a systemic as well as an organ-specific autoimmune disease, characterized by destructive lymphocytic infiltration of the salivary and lacrimal glands. We divided SS patients into three stages: stage I is glandular SS, stage II is extraglandular SS, and stage III is extraglandular SS with lymphoid malignancy. The lymphoaggressive nature of the disease appears to lead SS patients from stage I to II and from stage II to III. However, stage III patients made up only 5% of SS patients. Many patients remain stable in stages I or II for as long as 10 or 20 years. Therefore, we can assume that there are factors which trigger patients in stages I or II to progress to stages II or III and that only those patients who have such factors progress from stages I or II to stages II or III, respectively. Accumulation in the salivary glands or in the peripheral blood of B cells which have rearrangement of the RF-related germline gene Vg or over-expression of the bcl-2 gene in the lymphoepithelial lesion might be included among these factors.

[Lymphoproliferative disorders in patients with Sjögren's syndrome--Vg gene rearrangement and expression of bcl-2 protein]

Sjögren's syndrome (SS) is a unique disease which develops a high incidence of lymphoproliferative disorders (LPD) such as monoclonal gammopathy or malignant lymphoma. In order to elucidate the mechanism responsible for the emergence of monoclonal B cell proliferation at the site of a chronic autoimmune reaction, the rheumatoid factor (RF) related germline gene Vg and expression of the bcl-2 gene in the lymphoepithelial lesion (LEL) were studied. Predominant usage of the Vg or Vg-like genes was found in the peripheral blood leukocytes in SS patients and abundant expression of bcl-2 protein in the lymphocytes in and around the LEL were observed. These results suggest that RF clones were activated resulting into monoclonal proliferation and overexpression of bcl-2 protein play a role allowing the cell to escape a apoptotic cell death resulting into the increased risk of monoclonal proliferation in SS patients.

Differential response to transforming growth factors-beta1 and beta2: connective tissue deposition in animal models

The ability of transforming growth factor (TGF)-beta(1) and TGF-beta(2) to promote connective tissue deposition were compared in different animal models. A single subcutaneous injection of TGF-beta(2) in collagen/heparin gel carrier promoted markedly more extensive development of connective tissue than TGF-beta(1) at the site of injection in both neonatal and adult mice. Both TGF-beta(1) and TGF-beta(2) promoted deposition of dense and well-vascularized connective tissue matrix infiltrated with macrophages and fibroblasts. However, the results of immunohistochemical analyses suggested that TGF-beta(2) promoted an accumulation of more macrophages in the connective tissue than TGF-beta(1). Similar differences in the extent of connective tissue development were observed in neonatal mice when these factors were administered as a solution, without the collagen/heparin gel carrier. TGF-beta(2) was also more potent than TGF-beta(1) in domestic pigs. However, in guinea pigs, TGF-beta(1) promoted more extensive connective tissue development than TGF-beta(2). These results suggest that the differential connective tissue response to TGF-beta(1) and TGF-beta(2) is species dependent. However, the differences in the physical and chemical properties of these factors may account in part for the differential response as well.

Rapid ventricular induction of brain natriuretic peptide gene expression in experimental acute myocardial infarction

BACKGROUND

We have demonstrated that brain natriuretic peptide (BNP) is a cardiac hormone predominantly synthesized in and secreted from the ventricle. We have also reported that, compared with atrial natriuretic peptide (ANP), the plasma concentration of BNP is increased to a greater degree in patients with congestive heart failure and more rapidly in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

To investigate ventricular gene expression of BNP in AMI, we analyzed plasma and ventricular BNP concentrations along with ventricular BNP mRNA in rats with AMI produced by coronary artery ligation. The BNP concentration in the left ventricle increased about 2-fold as early as 12 hours postinfarction and 5-fold 1 day postinfarction compared with sham-operated rats, whereas left ventricular ANP concentration remained unchanged within 1 day. The tissue concentration of BNP increased in the noninfarcted region as well as in the infarcted region. The surviving myocytes in and around the necrotic tissues in the infarcted region were intensely stained with the anti-BNP antiserum, indicating augmented production in the remaining myocytes in the infarcts. The BNP concentration in the right ventricle also increased about 10-fold 12 hours postinfarction, whereas the ANP concentration remained unchanged within 12 hours. Northern blot analysis revealed that BNP mRNA expression was augmented 3-fold in the left ventricle as early as 4 hours postinfarction. In contrast, ANP mRNA expression was unchanged. Reflecting the rapid induction of ventricular BNP production, the plasma BNP concentration rose to about 100 pg/mL 12 hours postinfarction (sham-operated rats, < 70 pg/mL).

CONCLUSIONS

These results demonstrate the rapid induction of ventricular BNP gene expression in rats with AMI compared with ANP and suggest that BNP gene expression in the ventricle is regulated distinctively from ANP gene expression against acute ventricular overload. They also suggest that the BNP gene can be one of the acutely responsive cardiac genes for the ventricular overload and suggest a possible pathophysiological role of BNP distinct from ANP in AMI.

Synthesis and crystal structure of methyl 4-6-dideoxy-4-(3-deoxy-L- glycero-tetronamido)-2-O-methyl-alpha-D-mannopyranoside, the methyl alpha-glycoside of the terminal unit, and presumed antigenic determinant, of the O-specific polysaccharide of Vibrio cholerae O:1, serotype Ogawa

Methyl 4-azido-4,6-dideoxy-3-O-benzyl-alpha-D-mannopyranoside and its analogous 3-O-(4-methoxybenzyl) derivative were methylated and the 2-O-methyl derivatives formed were converted into methyl 4-amino-4,6-dideoxy-2-O-methyl-alpha-D- mannopyranoside [sequence: see text]. Reaction of the latter with 3-deoxy-L-glycero-tetronolactone gave the methyl glycoside of 4,6-dideoxy-4-(3-deoxy-L-glycero- tetronamido)-2-methyl-alpha-D-mannopyranose [sequence: see text], the monosaccharide that is reported to be the terminal moiety of the O-specific polysaccharide of Vibrio cholerae O:1, serotype Ogawa. The unit cell packing of the compound, which crystallized as a monohydrate, differs from that of the previously described crystalline compound lacking the 2-O-methyl group. The unmethylated sugar is the terminal moiety of the O-specific polysaccharide of Vibrio cholerae O:1, serotype Inaba. The crystal structure of methyl 4,6-dideoxy-2-O- methyl-4-trifluoroacetamido-alpha-D-mannopyranoside [sequence: see text] is also described.

Different expression of esterase variants in rat hepatic and hepatoma-derived cell lines detected by electrophoresis

Esterases in nine rat hepatic and hepatoma-derived cell lines and normal rat liver homogenate were detected by polyacrylamide gel electrophoresis coupled with active staining with alpha-naphthyl acetate or butyrate as a substrate. The esterase band patterns of the non-cancerous and oncogene-transformed cell lines were alike, but different from those of hepatoma cell lines and normal rat liver homogenate. The former groups of cells might have completely lost the characteristics of rat liver parenchymal cells, or else they might have their origin at cells other than liver parenchyma. The esterase patterns of the hepatoma cell lines (e.g., McA-RH7777) and the normal rat liver highly resembled with each other, exemplifying the slight biochemical deviation of cancer from normal cells. However, two-dimensional electrophoretogram for the McA-RH7777 cell line showed a prominent esterase spot (pI 6.0-M(r) 110 kDa) that was lacking in the normal liver. This result indicates that there is invariably some change in esterase expression between the cancer cells and the normal liver cells.

Characterization of the 5'-flanking region and chromosomal assignment of the human brain natriuretic peptide gene

Brain natriuretic peptide (BNP) is a cardiac hormone that occurs predominantly in the ventricle, and synthesis and secretion of BNP are greatly augmented in patients with congestive heart failure and in animal models of ventricular hypertrophy. In order to elucidate the molecular mechanisms underlying the human BNP gene expression in the heart, the human BNP gene was isolated from a size-selected genomic minilibrary. The 1.9-kb human BNP 5'-flanking region (-1813 to +110) contained an array of putative cis-acting regulatory elements. Various lengths of the cloned 5'-flanking sequences were linked upstream to the bacterial chloramphenicol acetyltransferase (CAT) gene, and their promoter activities were assayed. The 1.9-kb promoter region showed a high-level CAT activity in cultured neonatal rat ventricular cardiocytes. When the CT-rich sequences (-1288 to -1095) were deleted, the high-level activity was reduced to approximately 30%. The 399-bp BNP 5'-flanking region (-289 to +110) showed approximately 10% activity of the 1.9-kb region. Furthermore, using human-rodent somatic hybrid cell lines, the BNP gene was assigned to human chromosome 1, on which the atrial natriuretic peptide gene is localized. The present study leads to a better understanding of the molecular mechanisms for the human BNP gene expression in the heart.

CD68+ reactive histiocytosis complicating early gastric cancer

A peculiar form of reactive, non-granulomatous proliferation of CD68+ histiocytes was demonstrated, for the first time, in the submucosal layer just beneath the IIa-type early gastric adenocarcinoma that focally invaded submucosal lymphatics. The histiocytic cells possessed plump eosinophilic and often foamy cytoplasm and eccentric small nuclei with apparent nucleoli. They contained periodic acid-Schiff-reactive granules, and were further immunoreactive for lysozyme and alpha 1-antitrypsin. The infiltration was ill-defined, and partly involved the tunica muscularis mucosae and the proper muscle layer. Markers of epithelial cells, Langerhans' histiocytes, smooth muscle cells and myofibroblasts were all negative.

Molecular cloning of rat obese cDNA and augmented gene expression in genetically obese Zucker fatty (fa/fa) rats

The obese (ob) gene has recently been isolated through a positional cloning approach, the mutation of which causes a marked hereditary obesity and diabetes mellitus in mice. In the present study, we isolated rat ob cDNA and examined the tissue distribution of the ob gene expression in rats. We also studied the gene expression in genetically obese Zucker fatty (fa/fa) rats. The rat ob gene product, a 167 amino acid protein with a putative signal sequence, was 96 and 83% homologous to the mouse and human ob proteins, respectively. Northern blot analysis using the rat ob cDNA probe identified a single mRNA species of 4.5 kb in size in the adipose tissue, while no significant amount of ob mRNA was present in other tissues in rats. The ob gene was expressed in the adipose tissue with region specificities. The rank order of the ob mRNA level in the adipose tissue was epididymal, retroperitoneal, and pericardial white adipose tissue > mesenteric and subcutaneous white adipose tissue > or = interscapular brown adipose tissue. The ob gene expression occurred in mature adipocytes rather than in stromalvascular cells isolated from the rat adipose tissue. Expression of the ob gene was markedly augmented in all the adipose tissue examined in Zucker fatty (fa/fa) rats at the stage of established obesity. The present study leads to the better understanding of the physiologic and pathophysiologic roles of the ob gene.

Rapid transcriptional activation and early mRNA turnover of brain natriuretic peptide in cardiocyte hypertrophy. Evidence for brain natriuretic peptide as an "emergency" cardiac hormone against ventricular overload

We previously demonstrated that brain natriuretic peptide (BNP) is a cardiac hormone mainly produced in the ventricle, while the major production site of atrial natriuretic peptide (ANP) is the atrium. To assess the pathophysiological role of BNP in ventricular overload, we have examined the gene expression of BNP, In comparison with that of ANP, in a model of cardiac hypertrophy using cultured neonatal rat ventricular cardiocytes. During cardiocyte hypertrophy evoked by endothelin-1, Phenylephrine, or PMA, the steady state level of BNP mRNA increased as rapidly as the "immediate-early" induction of the c-fos gene expression, and reached a maximal level within 1 h. Actinomycin D, a transcriptional inhibitor, completely diminished the response, while the translational blocked with cycloheximide did not inhibit it. In contrast, ANP mRNA began to increase 3 h after the stimulation, and accumulated during cardiocyte hypertrophy. The BNP secretion from ventricular cardiocytes was also stimulated, more rapidly than the ANP secretion. Furthermore, the turnover of BNP mRNA was significantly faster than that of ANP mRNA, being consistent with the existence of AUUUA motif in the 3'-untranslated region of BNP mRNA. These results demonstrate that the gene expression of BNP is distinctly regulated from that of ANP at transcriptional and posttranscriptional levels, and indicate that the characteristics of the BNP gene expression are suitable for its possible role as an " emergency" cardiac hormone against ventricular overload.

Synthesis and mitogenic activity of nonreducing-sugar subunit analogs of bacterial lipid A composed only of 3-hydroxytetradecanoic acid and its homologs

Novel analogs of the nonreducing-sugar subunit of bacterial lipid A, which were composed only of 3-hydroxytetradecanoic acid and its homologs, were synthesized. These analogs exhibited significant mitogenic activity.

Tumour angiogenesis and tumour cell proliferation as prognostic indicators in gastric carcinoma

Tumour growth depends on neovascularisation and tumour cell proliferation. Factor VIII-related antigen (F-VIII RA) localises to vascular endothelium. Expression of proliferating cell nuclear antigen (PCNA) is correlated with cell proliferation. We investigated the correlation between the expression of these antigens and prognosis in gastric carcinoma. A total of 108 specimens resected from patients with gastric carcinoma were investigated by staining with monoclonal antibodies against F-VIII RA and PCNA. Microvessel count (MVC; the mean number of microvessels in the five areas of highest vascular density at 200 x magnification) and PCNA labelling index (PCNA LI; percentage of positive cells in more than 500 tumour cells) were determined. The results showed that prognosis was significantly worse in patients who had a tumour with a high MVC (16 or greater) or a high PCNA LI (42% or greater) than in those patients who had a tumour with a low MVC (less than 16) or a low PCNA LI (less than 42%). Furthermore, MVC was significantly associated with the risk of hepatic recurrence. In conclusion, both MVC and PCNA LI may be good prognostic indicators in patients with gastric carcinoma.

Inhibition by beraprost sodium of thrombin-induced increase in endothelial macromolecular permeability

Effect of beraprost sodium (BPS), a long-acting and orally active stable analogue of PGI2, on the macromolecular permeability of cultured vascular endothelial cells (HUVEC) was detected by the transport of FITC-albumin. Thrombin treatment resulted in induction of FITC-albumin transport across the endothelial cell monolayer. The albumin transport induced by thrombin was not accompanied by any damage to the cells. BPS had no effect on the permeability of resting endothelial monolayers, while BPS inhibited the thrombin-induced increase in the albumin permeability in a dose-dependent manner (30-1000 nM). Treatment of the cells with PGI2 or dibutyryl cAMP caused a significant inhibition of the thrombin-induced increase in the albumin permeability. These results strongly suggested that BPS suppressed the thrombin-induced macromolecular permeability in HUVEC through the elevation of its intracellular cAMP, and that BPS was a suppressor against inflammatory vascular changes such as exudation.

[Development of apoptosis induced by whole-body irradiation in murine liver]

Apoptosis is known to be induced by radiation. However, the correlation between radiation-induced apoptosis and radiation injury in tumors in vivo has been unclear. In this paper, we report the study of apoptosis induced by whole-body irradiation using an immunohistochemical technique to detect DNA fragmentation in murine liver. A dose of 7 Gy was employed as LD50/30. DNA fragmentation was observed 30 min after radiation, and it peaked between 1 and 6 hours. DNA fragmentation could be detected 48 hours after radiation in capillary endothelium. This study was able to reveal the development of radiation-induced apoptosis in the liver by detecting DNA fragmentation in situ.