Identification and characterization of a novel human phosphatidylinositol 4-kinase

The extensive sequence homology that exists among the catalytic domains of phosphatidylinositol 3- and 4-kinases allowed us to clone a novel human gene encoding a putative phosphatidylinositol kinase, NPIK. Among other known phosphatidylinositol 3- and 4-kinases, NPIK was most closely related to yeast PIK1 phosphatidylinositol 4-kinase. Several forms of NPIK cDNAs were isolated, and expression of NPIK message was detected in a wide variety of tissues. Fluorescence in situ hybridization and radiation hybrid analyses assigned the NPIK gene to human chromosome 1. Recombinant NPIK protein catalyzed a conversion from phosphatidylinositol to phosphatidylinositol 4-phosphate. The catalytic activity of NPIK was augmented by Triton X-100, and was reduced in the presence of adenosine. Using green fluorescent protein system we determined that NPIK is localized in the cytoplasm. Taken together, the data suggest that NPIK may play a pivotal role in regulating the synthesis of phosphatidylinositol 4-phosphate at the site(s) accessible from cytoplasm.

Pentaerythritol tetranicotinate (niceritrol) decreases plasma lipoprotein(a) levels

We determined the most effective dosage of pentaerythritol tetranicotinate (niceritrol) to reduce plasma lipoprotein(a) [Lp(a)] levels in 44 Japanese patients (16 men and 28 women; mean age, 59.2 +/- 10.8 years) with hyperlipidemia types IIa, IIb, and IV. Patients received oral niceritrol at a dosage of 750 mg (3 tablets)/d for 8 weeks, followed by 1,500 mg (6 tablets)/d for 8 weeks. Administration of niceritrol 750 mg/d for 8 weeks decreased total and low-density lipoprotein (LDL) cholesterol in patients with type IIa hyperlipidemia and decreased triglycerides in patients with type IV hyperlipidemia, but did not affect Lp(a). However, niceritrol 1,500 mg/d for 8 weeks decreased Lp(a) in patients with initial Lp(a) levels greater than 30 mg/dL in addition to decreasing total and LDL cholesterol and triglycerides. These results suggest that the effective dosage of niceritrol to reduce the serum Lp(a) concentration in Japanese hyperlipidemic patients with a high Lp(a) level (> or = 30 mg/dL) is greater than 1,500 mg/d.

Isolation and mapping of karyopherin alpha 3 (KPNA3), a human gene that is highly homologous to genes encoding Xenopus importin, yeast SRP1 and human RCH1

From a human fetal-brain cDNA library, we isolated and characterized a novel gene (KPNA3) encoding a protein highly homologous to certain nuclear transport proteins of Xenopus and human. The complete cDNA clone, designated karyopherin alpha 3, contained an open reading frame of 1,563 nucleotides encoding 521 amino acids. The predicted amino acid sequence showed 48%, 45% and 48% identity with Xenopus importin, yeast SRP1 and human RCH1, respectively. The similarities among these proteins suggest that karyopherin alpha 3 may be involved in the nuclear transport system. Eight repeats of the arm motif were well conserved among these proteins. The N-terminal region of the predicted karyopherin alpha 3 product was highly basic and the C-terminal region was strongly acidic. A 4.3-kb transcript was expressed in all adult human tissues examined by Northern blotting. The cDNA clone was assigned to chromosome band 13q14.3 by fluorescence in situ hybridization.

Cloning and chromosome assignment to 1q32 of a human cDNA (RAB7L1) encoding a small GTP-binding protein, a member of the RAS superfamily

A full-length cDNA homologous to RAB7, a member of the RAB-related GTP-binding protein subfamily, was isolated from a human placenta cDNA library. This cDNA, designated RAB7L1, has an open reading frame of 609 nucleotides encoding 203 amino acids. Northern analysis showed that the mRNA is ubiquitously expressed in human tissues, although signal intensities were different among the various organs examined. This gene was located on chromosome band 1q32 by fluorescence in situ hybridization.

Inhibition of lipid hydroperoxidation of low density lipoprotein by the Ca(2+)-channel and alpha 1-adrenoceptor antagonist monatepil maleate

The antioxidative effect of monatepil maleate (CAS 103379-03-9, AJ-2615), a new antihypertensive agent, was investigated by measuring its ability to inhibit copper-induced lipid hydroperoxidation of low density lipoprotein (LDL) and was compared with those of diltiazem (Ca(2+)-channel antagonist), prazosin (alpha 1-adrenoceptor antagonist), and probucol. The concentration of AJ-2615 required to inhibit copper-induced lipid hydroperoxidation of LDL by 50% (IC50) was 28 mumol/l. The IC50 values for diltiazem, prazosin, and probucol were > 1 mmol/l, > 1 mmol/l, and 17 mumol/l, respectively. These results indicate that AJ-2615 has the same potent antioxidative effect as probucol and suggest that a previously reported ability of AJ-2615 to inhibit the progression of atherosclerosis may be due to this antioxidative property. In addition, the dihydrodibenzothiepine ring of AJ-2615 may have an antioxidative functions.

New method for assaying free and total cholesterol in cultured cells by high-pressure liquid chromatography

We developed a simple, sensitive and accurate method for assaying cellular free and total cholesterol by monitoring 4-cholesten-3-one, a conversion product of the cholesterol oxidase-catalyzed oxidation of the free cholesterol that has a strong chromophoric alpha, beta-unsaturated ketone at 240 nm, using a high-pressure liquid chromatographic system. This method measured picomole quantities of free and total cholesterol and precisely determined their concentrations in cells (10(4) range) in culture using 7 beta-hydroxycholesterol as an internal standard.

[Endothelial dysfunction of the infarct-related coronary artery after reperfusion therapy]

The response of the infarct-related coronary artery to acetylcholine (20, 30, 50 micrograms) was investigated in 30 patients without restenosis during a 4-month follow-up period after direct percutaneous transluminal coronary angioplasty (PTCA) of the left proximal anterior descending coronary artery. The patients were divided into two groups according to wall motion as obtained by the centerline method from a left ventricular angiogram: moderate group (n = 10) with reduced wall motion with less than 20 abnormal contraction segments (moderate reduction at the infarcted site), severe group (n = 20) with reduced wall motion with 20 or more abnormal contraction segments (severe reduction). The acetylcholine-induced percentage changes in luminal diameter were assessed at the PTCA site and the distal portion of the coronary artery and the effect of acetylcholine was compared at the two sites. Coronary artery diameter in the moderate and severe groups displayed 8.1 +/- 24.9% and 7.4 +/- 30.8% contraction at the PTCA site and 38.3 +/- 46.3% and 72.5 +/- 28.2% contraction at the distal portion, respectively. Severe group had greater contraction at the distal portion than at the PTCA site. Vasoconstriction of the patent infarct-related coronary artery tended to occur in the infarcted area where wall motion was severely affected. In addition, endothelial dysfunction appears to be induced by a lengthy interruption of epicardial coronary blood flow and is present in the patent infarcted coronary artery without restenosis.

Atherosclerotic disease in marked hyperalphalipoproteinemia. Combined reduction of cholesteryl ester transfer protein and hepatic triglyceride lipase

Hyperalphalipoproteinemia (HALP) has been regarded as a beneficial state accompanied by a longevity syndrome. However, we reported the cases of markedly hyperalphalipoproteinemic subjects with juvenile corneal opacification. The patients had reduced postheparin hepatic triglyceride lipase (HTGL) activities, and one of them has recently been identified to be homozygous for a missense mutation in exon 15 (D442: G) in the cholesteryl ester transfer protein (CETP) gene. In the current study, to elucidate the clinical significance of and atherogenicity in marked HALP, we determined the incidence of atherosclerotic cardiovascular disease (ACD) in patients with marked HALP and characterized the lipoprotein abnormalities in those who had ACD, focusing especially on CETP and HTGL. The subjects were 201 patients (111 males and 90 females) with marked HALP ( > or = 2.58 mmol/L [100 mg/dL]), 67% of whom were demonstrated to have the CETP gene mutations in the intron 14 splice donor site or in exon 15. Their mean age was 54 +/- 15 years. Plasma levels of total cholesterol, HDL cholesterol, and triglyceride in all subjects were 6.28 +/- 1.78, 3.15 +/- 0.90, and 1.08 +/- 0.53 mmol/L, respectively. Ten of the male patients (9.0%) and two of the female patients (2.2%) had apparent ACD such as myocardial infarction, angina pectoris, and peripheral vascular diseases. Ten patients with HALP who had ACD were identified to be heterozygotes for CETP deficiency. To further clarify the characteristics of marked HALP in patients with ACD, we compared the plasma lipids, lipoproteins, CETP, and HTGL activities between heterozygotes for CETP deficiency who were with and without ACD.

Molecular cloning of a novel human cDNA, RT14, containing a putative ORF highly conserved between human, fruit fly, and nematode

From a human fetal-brain cDNA library we isolated a novel gene, designated RT14, whose cDNA contained an open reading frame of 375 nucleotides encoding 125 amino acids. A 71-amino-acids region of the predicted peptide sequence showed 62% identity with a putative peptide encoded in the region close to Drosophila Tra-2. It also showed significant homology with the putative peptide of T20G5.10 of C. elegans. Northern-blot analysis revealed expression of 0.7-kb and 1.1-kb transcripts in all human tissues examined.

Opposite effects on cholesterol metabolism and their mechanisms induced by dietary oleic acid and palmitic acid in hamsters

The effects of dietary oleic acid on cholesterol metabolism were investigated and compared with those of palmitic acid in hamsters. Addition of 5% oleic acid to a 0.1% cholesterol-supplemented diet decreased plasma total cholesterol, very low density lipoprotein (VLDL) cholesterol, and low density lipoprotein (LDL) cholesterol, increased hepatic LDL receptor activity, and decreased plasma cholesteryl ester transfer protein (CETP) activity in comparison with 0.1% cholesterol alone. In contrast, addition of 5% palmitic acid to a 0.1% cholesterol-supplemented diet increased total cholesterol and LDL-cholesterol, increased plasma CETP activity, and suppressed hepatic LDL receptor activity to a greater extent than 0.1% cholesterol alone. Neither oleic acid nor palmitic acid altered hepatic microsomal 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity, but oleic acid increased hepatic microsomal cholesterol 7 alpha-hydroxylase activity. These results suggest that dietary oleic acid inhibits the increases in total, VLDL-, and LDL-cholesterol induced by dietary cholesterol by preventing both LDL receptor suppression and increased CETP activity, whereas dietary palmitic acid augments the cholesterol-induced increases in total and LDL-cholesterol by both further suppression of LDL receptor activity and further stimulation of CETP activity.

Developmental expression of KG-CAM in the rat neostriatum

The present study examines the developmentally regulated expression pattern of an Ig superfamily member, KG-CAM, in the neostriatum of the rat. KG-CAM is a 90-kDa glycoprotein that is related to the DM-GRASP/Neurolin family of adhesion molecules. In the embryonic and early postnatal neostriatum, the distribution of KG-CAM correlates with the distribution of dopaminergic terminals. Early in neostriatal development, KG-CAM is found in the tyrosine hydroxylase-positive patches. In the maturing neostriatum, the levels of KG-CAM remain high within the patches, and KG-CAM upregulates in the matrix compartment. As the neostriatum is reaching its adult morphology, 5 weeks postnatal, the expression of KG-CAM in the matrix is approximately equal to that of the patches. When the distribution of KG-CAM is examined at the ultrastructural level, the immunoreactivity is localized to the external surface of neuronal and glial profiles in the neuropil. KG-CAM does not appear to be associated with the guidance of dopaminergic axons from the substantia nigra to the striatum, for this pathway is not immunopositive for this member of the Ig superfamily. The present study identifies an Ig superfamily member, KG-CAM, that appears to play a major role in the development of the neostriatum. Furthermore, the high levels of KG-CAM in the adult neostriatum suggest that this Ig superfamily member may be involved in maintaining the integrity of this structure in the adult rat.

Effect of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, on hepatic cholesterol 7 alpha-hydroxylase, acyl-coenzyme A: cholesterol acyltransferase, and bile lipid secretion in the hamster with intact enterohepatic circulation

The effects of administration of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, on hepatic cholesterol 7 alpha-hydroxylase and acyl-coenzyme A: cholesterol acyltransferase (ACAT) activities and bile lipid secretion were investigated in Syrian golden hamsters. Continuous administration of pravastatin induced no significant changes in hepatic cholesterol content, ACAT and cholesterol 7 alpha-hydroxylase activities, or bile lipid and acid composition. Abrupt withdrawal of pravastatin induced increases in hepatic cholesterol content and ACAT activity and no change in hepatic cholesterol 7 alpha-hydroxylase activity, and increased cholesterol saturation in bile. Hepatic cholesterol 7 alpha-hydroxylase activity paralleled hepatic mRNA levels of this enzyme. These results suggest that a change in hepatic cholesterol metabolism induced by continuous administration of pravastatin maintains a constant net balance of hepatic cholesterol content. In addition, the drug has no deleterious influence on metabolism of bile lipids and acids and related enzymes, except for a transient increase in cholesterol saturation in bile induced by an inappropriate increase in hepatic cholesterol content and a lack of response of cholesterol 7 alpha-hydroxylase activity to changes in hepatic cholesterol content upon abrupt withdrawal of pravastatin.

Subperiosteal tissue expansion for mandibular augmentation with hydroxylapatite particles: an experimental study

PURPOSE

The utility of subperiosteal tissue expansion (STE) for mandibular augmentation with hydroxylapatite (HA) particles was evaluated experimentally in two groups of dogs.

MATERIALS AND METHODS

Eight grams of solid HA particles were implanted in previously formed bilateral subperiosteal expanded beds on the mandible. In one group, the HA particles were implanted in the intact subperiosteal expanded bed and in the other the newly formed capsule overlying the bone was removed before implantation of HA.

RESULTS

Despite marked augmentation with a large number of HA particles, there was neither deformity nor infection of the implants, which maintained the original desired contour. The firm fibrous capsule formed by STE allowed consolidation of the HA particles and prevented their migration. In the first group, although histologic evidence of bony union of the implanted particles was not seen even after 2 months, clinical immobilization of the grafts was achieved in 1 to 2 months. After 1 year, substantial bone growth into the implants was observed. In the second group, clinical immobilization was observed even after 2 weeks. Histologic evidence of bony union of the particles located along the surface of the mandible was observed after 1 or 2 months. In these specimens, however, marked bone resorption of the mandibular cortex, was also noted. No evidence of bone or osteoid formation on the expanded periosteal side was noted in either group.

CONCLUSION

These results provide fundamental data regarding mandibular augmentation using STE, and indicate that the subperiosteal expanded bed is an excellent recipient site for onlayed implants.

Microsurgical anatomy of the lower cervical spine and cord

The authors dissected the cervical spine and its surrounding structures from 40 adult cadavers under a surgical microscope. The anterior part of the spine and spinal cord was examined after vertebrectomy. The posterior longitudinal ligament (PLL) consists of two layers; the anterior one is termed the deep layer, and the posterior one is termed the superficial layer. These two layers adhered together loosely. In the lateral portion of the spinal canal, the superficial layer joined the periradicular sheath at the level of the intervertebral disc spaces and joined the dura mater at the level of the vertebral bodies. After the removal of the deep layer, the anterior internal vertebral venous plexus was seen on top of the lateral part of the superficial layer. The venous plexus was embedded between the double-layered PLLs, was not located in the epidural space, and was not seen in the medial part of the PLL. The PLL without venous channels on top of it was about 10 mm in width at the levels of the intervertebral disc and about 5 mm at the levels of the vertebral body. The anterior root exit zone (AREZ) was an elliptical shape; the transverse length of the AREZ was about 2 mm, and the longitudinal length was 10 to 15 mm. The average number of anterior rootlets on the AREZ was 17 to 25 and tended to decrease in the lower cervical spinal cord. The posterior structures were examined after en bloc laminectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of a functional receptor differing from the LDL receptor that catabolizes chylomicron remnant in Hep G2 cells

We investigated types of lipoprotein receptors on Hep G2 cells using a monoclonal antibody against the LDL receptor. IgG-C7 inhibited the binding and internalization of 125I-labeled low density lipoprotein (LDL) in Hep G2 cells with upregulated and downregulated LDL receptors by 90% of control values. Binding and internalization of 125I-labeled chylomicron remnant in Hep G2 cells with upregulated and downregulated LDL receptors was 50% and 85%, respectively, of control values after exposure to IgG-C7. Excess unlabeled chylomicron remnant inhibited binding and internalization of 125I-labeled chylomicron remnant in Hep G2 cells with downregulated LDL receptors completely. Pronase treatment abolished binding and internalization of 125I-labeled LDL and 125I-labeled chylomicron remnant in Hep G2 cells. When solubilized fractions of Hep G2 cells were immunoprecipitated with IgG-C7, the binding activity of 125I-labeled chylomicron remnant to reconstituted vesicles was unchanged. 45Ca blotting analysis showed the presence of 45Ca binding protein (approximately 600 kDa) in Hep G2 cells. The amount of 45Ca binding protein was not affected by cholesterol and was abolished by pronase treatment. These results suggest the existence of a functional receptor other than the LDL receptor that catabolizes chylomicron remnant in Hep G2 cells and that this receptor may correspond to LDL receptor-related protein.

An animal model for subperiosteal tissue expansion

An animal model for subperiosteal tissue expansion is described. Small tissue expanders were placed bilaterally and inflated in the buccal subperiosteal pockets of the mandible. Additionally, subcutaneous expansion was performed in the breast region. Twenty-one dogs were used in three experimental groups to evaluate the optimal size of an expander for this model, the optimal inflation regimen, and the histologic changes following subperiosteal expansion. Hemicylindrical expanders, 20 mm in width, 10 mm in height, and 30 mm in length, inflated with 1 mL saline every four days, were used for this model. It was found that the periosteum was replaced by fibrous connective tissue during expansion. Capsule formation following subperiosteal expansion was much more rapid than that following subcutaneous expansion. A greater increase in vascularity was noted in the subperiosteal expansion group and the subperiosteal control group than in the subcutaneous expansion group. In the subperiosteal expansion group, a thick fibrous capsule, with minimal inflammatory response, was observed 1 week after full inflation. Leaving the fully inflated subperiosteal expanders in place more than 1 month accelerated the resorption of the underlying bone. These results support the previously reported empirical regimens of subperiosteal tissue expansion. Furthermore, the excellence of the subperiosteal expanded bed as a recipient site for onlay grafting was confirmed.

Effect of fluvastatin sodium (XU62-320), a new inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on the induction of low-density lipoprotein receptor in HepG2 cells

The effect of fluvastatin sodium (XU62-320), a new type of inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A, on the induction of LDL receptor in the human liver-derived cell line HepG2 was investigated. Fluvastatin sodium produced marked inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and induction of LDL receptor on HepG2 cells at a concentration of 0.1-1.0 microM. These results suggest that fluvastatin sodium has potential for use as a strong plasma cholesterol-lowering drug.