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Biomedical subjects

K Nakai

Publications and source records attributed to K Nakai.

At least 235 records · Page 13Linked to original sources
PubMed1994

Combined paraumbilical perforator skin flap and vascularized pubic bone graft.

A severely depressed deformity of the buccal region was repaired with an osteocutaneous flap based on the deep inferior epigastric vessels. This osteocutaneous flap has not been previously described in the literature. The superior pubic ramus, supplied by pubic branches from the deep inferior epigastric vessels, forms the bony portion of the combined flap. The cutaneous portion is also supplied by the deep inferior epigastric vessels and its thickness can be adjusted. This combination is useful when requiring both a thin flap and a flat bone.

Adult↗
PubMed1994

Lysophosphatidylcholine, a component of stromal phospholipids, as a candidate vasoconstrictive factor in stroma-free hemoglobin.

Stroma-free hemoglobin (SFH) contains a trace amount of phospholipids, which has been implicated in the toxic reactions associated with SFH. We analyzed stromal phospholipids by high-performance liquid chromatography and found that SFH contained small quantities of lysophosphatidylcholine (LPC), which is known to be capable of producing a defect in endothelium-dependent arterial relaxation, in addition to major classes of constituent phospholipids in red cell membrane. LPC content was determined to be 1.65 nmol/ml (hemoglobin 8.1 g/dl). To evaluate the role of these stromal phospholipids in SFH-induced vasoconstriction, we next examined the effect of lipids on vascular tone in rabbit aortic strips. Preincubation with the crude lipid extract or the LPC purified from SFH significantly inhibited acetylcholine-induced relaxation in phenylephrine-precontracted tissues. The LPC-induced inhibition was reversed by incubation of the tissues in the absence of lipids, indicating the functional integrity of endothelium. From these results, we propose a possibility that LPC, a component of stromal phospholipids, is a candidate for vasoconstrictive factors present in SFH.

Acetylcholine↗
PubMed1994

Deletion polymorphism of the angiotensin I-converting enzyme gene is associated with serum ACE concentration and increased risk for CAD in the Japanese.

BACKGROUND: The angiotensin I-converting enzyme (ACE) is a key component of the renin-angiotensin system thought to be important in the pathogenesis of hypertension and cardiovascular disease. Deletion polymorphism in the ACE gene may be a risk factor for myocardial infarction in the Caucasian population. However, this finding has not yet been investigated in the Japanese population. METHODS AND RESULTS: A 287-bp insertion/deletion polymorphism in intron 16 of the ACE gene was examined by polymerase chain reaction in a cross-sectional study of 100 healthy subjects and 178 patients with coronary artery disease (CAD) (70 angina pectoris, 108 myocardial infarction), whose serum ACE levels were concomitantly measured. Polymorphism of the ACE gene was characterized by three genotypes: two deletion alleles (genotype DD), two insertion alleles (genotype II), and heterozygous alleles (genotype ID). No differences could be detected among the three genotypes for total cholesterol, HDL cholesterol, and body mass index. Serum ACE levels were 11.4 +/- 2.7, 14.5 +/- 3.5, and 16.6 +/- 4.6 IU/mL for genotypes II, ID, and DD, respectively. In the study population, the genotype DD was more closely associated with CAD than the other two genotypes (ID and II). The frequency of deletion alleles was higher (0.58) in the CAD group than in healthy control subjects (0.42) (P < .05). Furthermore, multivessel disease was more strongly associated with deletion alleles than with insertion alleles (P < .05). CONCLUSIONS: A deletion polymorphism of the ACE gene is associated with serum ACE activity and increased risk for CAD in the Japanese.

Adult↗
PubMed1994

Acellular and cellular hemoglobin solutions as vasoconstrictive factor.

The inhibitory effects of acellular and cellular hemoglobin (Hb) solutions on endothelium-dependent vasorelaxation were investigated in rabbit thoracic aortic strips. As acellular Hb solutions, 2,3-diphosphoglycerate (DPG)-depleted Hb and pyridoxylated Hb were examined. Cellular Hb solutions included washed human fresh red cells and liposome Hb encapsulated with pyridoxal-5'-phosphate (PLP). The tissues were precontracted with phenylephrine (PE), after which acetylcholine (ACh) was added to elicit a steady-state relaxation. Acellular Hb solutions cumulatively reversed ACh-induced relaxation, and these inhibitory effects reached a plateau at 10 micrograms/ml. Increasing oxygen affinity by pyridoxylation had little effect on this. In contrast, both red cells and liposome Hb solution showed moderate inhibitory effects, and they reached a plateau at 1 mg/ml. These findings indicate that acellular Hb solutions are more potent inhibitors than cellular Hb solutions by a factor of about 100, and that the encapsulation of Hb is a preferable method to mimic the red cell.

2,3-Diphosphoglycerate↗
PubMed1994

The quality control of stroma-free hemoglobin: lysophosphatidylcholine, a component of stromal phospholipids, as candidate vasoconstrictive factor.

We characterized stromal phospholipids in stroma-free hemoglobin (SFH) by normal-phase and cation-exchange HPLCs, and found that SFH contained not only four phospholipids which were the major constituent classes in membrane, but also several peaks which were not yet identified. The residual amounts of these lipids in SFH were changed with storage of red cell concentrates. The four major phospholipids decreased concomitantly with storage, whereas the unidentified peaks increased after 21 days and then decreased after 48 days. We also found that SFH contained lysophosphatidylcholine (LPC) at 5.71 micrograms/ml, which was the deacylated metabolite of phosphatidylcholine (PC). These results suggest that stromal phospholipids are degradable. Since LPC is known to be capable of producing a defect in endothelium-dependent arterial relaxation, we next examined the effect of stromal lipids on vascular tone in rabbit thoracic aortic strips. Preincubation with the crude lipid extract or the LPC purified from SFH by TLC significantly inhibited acetylcholine (ACh)-induced relaxation in phenylephrine (PhE)-precontracted tissues. These observations have led to the proposal that LPC, a component of stromal phospholipids, induces vasoconstriction as a result of inhibition of endothelium-dependent vasorelaxation.

Animals↗
PubMed1994

[Analysis of the preceding R-R interval and the coupling interval on premature ventricular contractions].

Premature Ventricular Contractions (PVCs) are one of the common arrhythmias. Although the analysis of the preceding R-R interval and the coupling interval on the Holter electrocardiogram, the Lorenz plotting method, has been used to characterize mature of PVC, this analysis has typically been performed without regard to the morphological classification of the electrocardiogram waveforms. Therefore, we performed the Lorenz plotting after a PVC classification. We analyzed 45 cases with more than 1,000 PVCs per day. Twenty-six of the cases with PVCs had no organic heart disease (idiopathic PVC); nineteen of the cases with PVCs had organic heart disease (PVC with disease). Each R-R interval was analyzed after classification based on the morphology of each QRS wave of the PVC. The computer generated a two-dimensional plot of the relationship between the preceding R-R interval of PVC and the following coupling interval. The forms of PVCs were monoform in idiopathic PVC and were mostly multiform in PVC with disease. The patterns on Lorenz plotting in idiopathic PVC had a tendency to be uniform with small standard deviations. In contrast, multiform PVCs tended to be highly variable with large standard deviations. The value of SD was 32.1 +/- 12.0 msec in idiopathic PVC, and that of the slope "a" was 0.048 +/- 0.051 in PVC with disease. Using the SD values and the slope "a" values, we were able to classify idiopathic PVC vs. PVC with disease with a 95% sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Deletion polymorphism of the angiotensin I-converting enzyme gene associates with increased risk for ischemic heart diseases in the Japanese].

The Angiotensin I-converting enzyme (ACE) is a key component of the renin-angiotensin system thought to be important in the pathogenesis of hypertension and cardiovascular diseases. Previous studies showed that deletion polymorphism in the ACE gene might be a risk factor for myocardial infarction in the Caucasian population. However, this finding has not yet been reported in the Japanese population. In this study, a 287 base pair (bp) insertion/deletion polymorphism in intron 16 of the ACE gene was examined by polymerase chain reaction (PCR) in a cross-sectional study of 35 healthy subjects and 85 patients with ischemic heart diseases (IHD) (32 angina pectoris, 53 myocardial infarction). Polymorphism of the ACE gene was characterized by three genotypes; two deletion alleles (genotype DD), two insertion allele (genotype II) and heterozygotes alleles (genotype ID). No differences could be detected among the three genotypes for total cholesterol, high-density lipoprotein cholesterol, blood pressure and body mass index. The serum ACE activities in each II, ID and DD genotype were 10.1 +/- 2.1 microU/ml, 13 +/- 3.2 microU/ml, 14.2 +/- 5.4 microU/ml, respectively. In the population study the genotype DD was significantly associated with IHD when compared with the other two genotypes (ID and II). The frequency of deletion allele was higher (0.61) in the IHD group than in the normals (0.39) (chi 2 = 7.8, p < 0.01). These frequencies were not varied whether they had classic risk factors or not. Furthermore, coronary multivessel impairment was significantly associated with the deletion allele than with the insertion allele (chi 2 = 11.7, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Identification of O-phosphoamino acids in urine hydrolysate by gas chromatography-mass spectrometry.

The occurrence of O-phosphoserine (P-Ser), O-phosphothreonine (P-Thr) and O-phosphotyrosine (P-Tyr) in the hydrolysate of human urine was demonstrated. Urine samples were separated into non-adsorbed and adsorbed fractions by DEAE-cellulose column chromatography. After acid and base hydrolyses of these fractions, the O-phosphoamino acids in the hydrolysates were converted into their N-isobutoxycarbonyl methyl ester derivatives and identified by gas chromatography-mass spectrometry. By gas chromatography with flame photometric detection, the urinary contents of P-Ser, P-Thr and P-Tyr were estimated to be 945 +/- 3, 109 +/- 3 and 2.9 +/- 0.2 ng/ml, respectively.

Amino Acids↗
PubMed1993

A case of vessel perforation during interventional neuroradiological procedure. Operative findings of the perforated vessel.

A case of vessel perforation by a guide wire during an interventional neuroradiological procedure is reported. The patient was a 59-year-old woman with a left frontal basal arteriovenous malformation (AVM) fed by the left anterior cerebral artery. Transarterial embolization of the AVM was attempted. During the procedure, vessel perforation by the guide wire occurred at the left A1-A2 junction and resulted in subarachnoid hemorrhage, which stopped spontaneously. The patient developed progressive obstructive hydrocephalus, and surgical treatment was performed. The AVM was totally removed after ventricular drainage, and the arterial perforation site was explored. When clot around the left A1-A2 junction was removed, hemorrhage recurred. This hemorrhage was similar to what has been observed when a small perforating artery was avulsed. The hemorrhage site was coagulated under temporary occlusion of both A1 segments. Surgical intervention was probably not necessary for this type of bleeding if it had stopped spontaneously, because the rebleeding from the small pinhole would be unlikely, and the operation was more hazardous than the usual aneurysmal surgery.

Cerebral Arteries↗
PubMed1993

Complex occipital arteriovenous fistula associated with neurofibromatosis treated by embolization and surgery. Case report.

It is well known that neurofibromatosis is associated with various types of arteriovenous fistulas (AVF), but association with an occipital AVF has not been reported. We are reporting this case which was successfully treated with a combination of embolization and surgery. Superselective angiography defines the anatomic details of the fistula and intraoperative digital subtraction angiography (DSA) facilitates the surgery to cure the fistula. It is important to identify the best therapeutic options using angiographic information to treat a complex arteriovenous fistula.

Adult↗
PubMed1993

Percutaneous transluminal angioplasty for the M2 portion vasospasm following SAH: development of the new microballoon and report of cases.

A new silicone microballoon was developed for the percutaneous transluminal angioplasty of smaller intracranial vessels, such as A1, A2 and M2. This balloon was 0.5 x 2.0 mm in the deflated condition and became 2.2 x 6.5 mm inflated with 0.02 mL of fluid, and its bursting pressure was 2 atm. Two illustrative cases are presented. The first case was not treated in the M2 distribution. The second case of vasospasm of the left M2 portion was successfully treated with this new balloon, with prompt improvement of the neurological condition and cerebral circulation. The usefulness of our microballoon in treating a patient with vasospasm of small intracranial arteries is discussed.

Angioplasty, Balloon↗