Biomedical subjects

J Koizumi

Publications and source records attributed to J Koizumi.

At least 19 recordsLinked to original sources

PubMed2000

Covered stent implantation by the puncture method for the treatment of a small aneurysm of the common iliac artery.

A method to repair endovascular aneurysms with covered stents has recently been developed. In the present paper, the implantation of a covered stent through a 12Fr sheath by the puncture method for the treatment of an isolated aneurysm of the right common iliac artery is reported. The aneurysm was less than 3 cm in diameter, and computed tomography showed no signs of aneurysm rupture, but the patient nonetheless complained of right lower abdominal pain and constipation. It was decided to implant a covered stent in lieu of surgical repair because it was difficult to prove a causal relationship between the aneurysm and the patient's complaints. Fortunately, after implantation, the symptoms were resolved. In conclusion, it is possible to choose this less invasive type of therapy for the treatment of an isolated iliac artery aneurysm if the patient complains only of general malaise and there are no certain signs of an impending rupture, although surgery should be indicated regardless of aneurysm size.

Aged↗

PubMed2000

Long-term results of percutaneous transluminal angioplasty for hemodialysis shunt insufficiency

Purpose: The purpose of this study was to evaluate the long-term results of percutaneous transluminal angioplasty (PTA) for stenosis and/or occlusion of dialysis shunts. Methods: One hundred thirty-nine stenosed or thrombosed dialysis shunts (99 native fistulae, 37 grafts) in 122 patients were treated by PTA. In 39 cases, additional PTA for restenosis was performed. In total, 230 PTAs were performed (1-10 PTA/shunt). Results: The initial success rate was 86% in cases without occlusion. In contrast, the success rate in cases with occlusion was 53%, significantly worse than in the cases without occlusion. In cases in which initial success was obtained, primary cumulative patency rates at 3, 6, and 12 months were 87%, 60%, and 40%, respectively. With repeat PTA, secondary cumulative patency rates at 3, 6, 12, and 24 months were 96%, 83%, 63%, and 55%, respectively. Patency of native fistulae was better than patency of grafts. There was no significant relationship between the anatomical location of the stenoses and the patency rates. Conclusion: PTA is an effective treatment for shunt stenosis; although primary patency after PTA is not sufficient, repeated PTA increases patency.

Journal Article↗

PubMed2000

A case of aortoduodenal fistula occurring after surgery and radiation for pancreatic cancer.

The patient was a 58-year-old woman given curative treatment (pancreatectomy (body and tail) + intraoperative irradiation (25 Gy)) on the basis of a diagnosis of pancreatic carcinoma. Having a favorable postoperative course, she was discharged 24 days after surgery. A week after discharge, she was readmitted for a hemorrhagic gastric ulcer. She was later discharged again on conservative treatment, and followed up at the outpatient clinic, but nine months postoperatively, was readmitted complaining of loss of appetite and abdominal pain. Subsequent tests revealed stricture of the horizontal portion of the duodenum with distension oral to the stricture. Around the celiac artery, the paraaortic lymph nodes were swollen, and a diagnosis of stricture due to recurrent pancreatic carcinoma was made. On the day before bypass surgery was scheduled, the patient vomited blood, so the operation was postponed, conservative treatment such as blood transfusion was administered, and emergency angiography was performed simultaneously. The findings were an aortic pseudoaneurym 1 cm in diameter immediately below the origin of the superior mesenteric artery and between the left and right renal arteries, and a hemorrhage, caused by an aortoduodenal fistula, issuing from the horizontal portion of the duodenum. Hemostasis via a laparotomy was judged difficult, and so an indwelling stent-graft in the aorta was tried to stanch the blood, but without success. Another stent then had to be inserted within the first, thus stopping the flow, but the blood supply to the celiac artery, the superior mesenteric arteries and the renal arteries was impaired, and the patient died about six hours later. Postmortem examination revealed aortoduodenal fistula without recurrence of the carcinoma. The duodenal wall around the fistulous tract showed delayed radiation changes with deep ulceration. The intraoperative radiation may have played an important part in the formation of the fistula.

Aortic Diseases↗

PubMed1999

Early Lung Cancer Action Project: overall design and findings from baseline screening.

BACKGROUND: The Early Lung Cancer Action Project (ELCAP) is designed to evaluate baseline and annual repeat screening by low-radiation-dose computed tomography (low-dose CT) in people at high risk of lung cancer. We report the baseline experience. METHODS: ELCAP has enrolled 1000 symptom-free volunteers, aged 60 years or older, with at least 10 pack-years of cigarette smoking and no previous cancer, who were medically fit to undergo thoracic surgery. After a structured interview and informed consent, chest radiographs and low-dose CT were done for each participant. The diagnostic investigation of screen-detected non-calcified pulmonary nodules was guided by ELCAP recommendations, which included short-term high-resolution CT follow-up for the smallest non-calcified nodules. FINDINGS: Non-calcified nodules were detected in 233 (23% [95% CI 21-26]) participants by low-dose CT at baseline, compared with 68 (7% [5-9]) by chest radiography. Malignant disease was detected in 27 (2.7% [1.8-3.8]) by CT and seven (0.7% [0.3-1.3]) by chest radiography, and stage I malignant disease in 23 (2.3% [1.5-3.3]) and four (0.4% [0.1-0.9]), respectively. Of the 27 CT-detected cancers, 26 were resectable. Biopsies were done on 28 of the 233 participants with non-calcified nodules; 27 had malignant non-calcified nodules and one had a benign nodule. Another three individuals underwent biopsy against the ELCAP recommendations; all had benign non-calcified nodules. No participant had thoracotomy for a benign nodule. INTERPRETATION: Low-dose CT can greatly improve the likelihood of detection of small non-calcified nodules, and thus of lung cancer at an earlier and potentially more curable stage. Although false-positive CT results are common, they can be managed with little use of invasive diagnostic procedures.

Aged↗

PubMed1999

The subcellular localization of SF2/ASF is regulated by direct interaction with SR protein kinases (SRPKs).

Serine/arginine-rich (SR) proteins play an important role in constitutive and alternative pre-mRNA splicing. The C-terminal arginine-serine domain of these proteins, such as SF2/ASF, mediates protein-protein interactions and is phosphorylated in vivo. Using glutathione S-transferase (GST)-SF2/ASF-affinity chromatography, the SF2/ASF kinase activity was co-purified from HeLa cells with a 95-kDa protein, which was recognized by an anti-SR protein kinase (SRPK) 1 monoclonal antibody. Recombinant SRPK1 and SRPK2 bound to and phosphorylated GST-SF2/ASF in vitro. Phosphopeptide mapping showed that identical sites were phosphorylated in the pull-down kinase reaction with HeLa extracts and by recombinant SRPKs. Epitope-tagged SF2/ASF transiently expressed in COS7 cells co-immunoprecipitated with SRPKs. Deletion analysis mapped the phosphorylation sites to a region containing an (Arg-Ser)8 repeat beginning at residue 204, and far-Western analysis showed that the region is required for binding of SRPKs to SF2/ASF. Further binding studies showed that SRPKs bound unphosphorylated SF2/ASF but did not bind phosphorylated SF2/ASF. Expression of an SRPK2 kinase-inactive mutant caused accumulation of SF2/ASF in the cytoplasm. These results suggest that the formation of complexes between SF2/ASF and SRPKs, which is influenced by the phosphorylation state of SF2/ASF, may have regulatory roles in the assembly and localization of this splicing factor.

Glutathione Transferase↗

PubMed1999

Opposite effects on serum cholesteryl ester transfer protein levels between long-term treatments with pravastatin and probucol in patients with primary hypercholesterolemia and xanthoma.

Long-term effects of pravastatin and probucol on serum cholesteryl ester transfer protein (CETP) and xanthoma/xanthelasma size were compared. Twenty-three patients with primary hypercholesterolemia and xanthoma/xanthelasma, including 11 patients with heterozygous familial hypercholesterolemia, were treated with pravastatin (20 mg/day) or probucol (1000 mg/day) for 24 months. Serum CETP levels were measured by sandwich ELISA. In 11 patients (six men and five women, 55 +/- 2 [SE] yr) treated with pravastatin, serum cholesterol levels decreased from 262 +/- 13 to 229 +/- 13 mg/dl during the 24-month treatment period (P = 0.05). Serum HDL cholesterol levels were not changed. Serum CETP levels decreased from 2.5 +/- 0.2 to 2.0 +/- 0.2 microg/ml (-21%, P = 0.002). By contrast, in 12 patients (four men and eight women, 57 +/- 4 year) treated with probucol, serum cholesterol levels did not significantly decrease from 236 +/- 11 to 207 +/- 13 mg/dl. Serum HDL cholesterol levels decreased from 44 +/- 2 to 30 +/- 2 mg/dl (P = 0.009). Serum CETP levels increased from 2.3 +/- 0.1 to 2.8 +/- 0.2 microg/ml (+23%, P = 0.02). Xanthelasma regression was found in two of four patients (50%) each treated with pravastatin and probucol, respectively. In contrast, Achilles' tendon xanthoma regressed in four of five patients (80%) treated with pravastatin, but only in two of five patients (40%) treated with probucol. Patients with xanthoma/xanthelasma regression after 2 years treatment had higher baseline levels of serum CETP than those without regression (2.7 +/- 0.2 microg/ml [n = 9] versus 2.1 +/- 0.2 microg/ml [n = 7], P = 0.05). Serial changes in serum CETP levels during treatment with pravastatin and probucol were discordant, but not related to the degree of xanthoma regression. However, higher level of serum HDL3 cholesterol was an independent factor in the smaller size of Achilles' tendon xanthoma at baseline. In addition, higher levels of serum HDL3 triglyceride on lipid-lowering therapy (6 months) appear to be a common predictor of regression of Achilles' tendon xanthoma in the treatment with either pravastatin or probucol.

Achilles Tendon↗

PubMed1999

Plasma homocysteine level and development of coronary artery disease.

BACKGROUND: The plasma level of homocysteine is an independent risk factor for atherosclerotic vascular disease. The relationship between plasma homocysteine level and the onset of coronary artery disease (CAD) has not been established. OBJECTIVE: To investigate the relationship between plasma homocysteine level and the age at which CAD was diagnosed. METHODS: Fifty-seven male patients aged < or = 65 years (mean age 53 years) with angiographically proven symptomatic CAD seen consecutively and 138 age-matched male control subjects (mean age 52 years) free from atherosclerotic vascular disease were studied. They were divided into two subgroups, a group of younger subjects (aged < or = 55 years) and a group of older subjects (aged 56-65 years). RESULTS: Plasma homocysteine levels in CAD patients significantly exceeded those of control subjects (means 13.4 versus 10.6 nmol/ml, P = 0.0002). Plasma homocysteine level of subjects in younger CAD group was significantly higher than that of subjects in older CAD group (15.0 versus 11.3 nmol/ml, P = 0.03), and age and logarithmically transformed plasma homocysteine level exhibited a significant negative correlation (r = -0.28, P = 0.03) for subjects in CAD group. Among control subjects, members of our two age subgroups had similar plasma homocysteine levels. Younger CAD patients had significantly higher plasma homocysteine levels than did younger controls (15.0 versus 10.4 nmol/ml, P < 0.0001). However, for older groups there was no significant difference between plasma homocysteine levels in CAD patients and controls (11.3 versus 10.9 nmol/ml). Multiple regression analysis showed that only logarithmically transformed plasma homocysteine level was a significant predictor for age of onset of CAD. CONCLUSION: An elevated level of plasma homocysteine is more important in the development of premature CAD than it is in that of late-onset CAD among men.

Adult↗

PubMed1999

Abetalipoproteinemia caused by maternal isodisomy of chromosome 4q containing an intron 9 splice acceptor mutation in the microsomal triglyceride transfer protein gene.

Uniparental disomy (UPD), a rare inheritance of 2 copies of a single chromosome homolog or a region of a chromosome from one parent, can result in various autosomal recessive diseases. Abetalipoproteinemia (ABL) is a rare autosomal recessive deficiency of apoB-containing lipoproteins caused by a microsomal triglyceride transfer protein (MTP) deficiency. In this study, we describe a patient with ABL inherited as a homozygous intron 9 splice acceptor G(-1)-to-A mutation of the transfer protein gene. This mutation alters the splicing of the mRNA, resulting in a 36 amino acids, in-frame deletion of sequence encoded by exon 10. We analyzed chromosome 4, including MTP gene (4q22-24), using short tandem repeat markers. The proband has only his mother's genes in chromosome 4q spanning a 150-centimorgan region; ie, segmental maternal isodisomy 4q21-35, probably due to mitotic recombination. Nonpaternity between the proband and his father was excluded using 6 polymorphic markers from different chromosomes (paternity probability, 0.999). Maternal isodisomy (maternal UPD 4q) was the basis for homozygosity of the MTP gene mutation in this patient.

Abetalipoproteinemia↗

PubMed1999

[Clinical significance of serum lipoprotein(a) concentration in the elderly with regard to vascular complications and long-term prognosis].

To elucidate the clinical significance of lipoprotein(a) [Lp(a)] in the elderly, 48 patients with Lp(a) of 35 mg/dl or more [the high Lp(a) group] and 97 patients with Lp(a) less than 20 mg/dl [the low Lp(a) group] were enrolled to investigate their outcome for five years. At registration, they were all examined by brain computerized tomography (CT) for cerebrovascular diseases, B-mode ultrasonography (US) for carotid lesions, ECG for myocardial ischemia, and Doppler arteriography for the ankle pressure index (API). They were followed up completely to study survival rates, cause of death, and morbidity rates of vascular events, including occurrence of stroke, myocardial infarction, and aortic aneurysm as well as progression of the stage in arteriosclerosis obliterans. The mean age of the high Lp(a) group was 78.1, whereas that of the low Lp(a) group was 76.8. Baseline clinical findings revealed no difference in age or gender between the two groups, although a previous history of stroke, abnormal CT and US findings, and low API were more frequent in the high Lp(a) group than in the low Lp(a) group. In the high Lp(a) group [vs. the low Lp(a) group], 18 patients (vs. 21 patients) died within five years, which resulted in a cumulative mortality rate of 37.5% (vs. 21.6%) and an annual mortality rate of 9.4% (vs. 4.8%). Based on log-rank analysis, the survival rate of the high Lp(a) group was significantly lower than that of the low Lp(a) group. The most common causes of death were vascular events and pneumonia, more than half of them were aspiration pneumonia complicated with stroke. Ten patients in the high Lp(a) group had vascular events (vs. 8 patients). The morbidity rate of vascular events, most of which were cerebral infarction, was higher in the high Lp(a) group (annual morbidity rate 5.5%) than in the low Lp(a) group (1.8%). These findings suggested that serum Lp(a) concentration, genetically determined and remaining consistent throughout life, had influenced vascular wall damage over a long time with age, therefore, a high Lp(a) level might promote atherothrombosis. In the elderly, therefore, high Lp(a) level, resulting in symptomatic vascular lesions with organ dysfunction, is a distinct and independent poor prognostic risk factor.

Aged↗

PubMed1999

[A case of mediastinal myelolipoma].

Myelolipoma is a benign tumor composed of mature adipose tissue and hematopoietic tissue. It was mainly found in the adrenal grand, but there have been reports of extra-adrenal locations. Only 7 cases of mediastinal myelolipoma have been reported ever. We have experienced a case of mediastinal myelolipoma surgically resected from a 55-year-old-man. He has visited our department because of chest pain. Chest X-ray showed typical pneumothorax, but abnormal mediastinal shadow was remarked. Chest CT showed a well circumscribed mass with fat and soft-tissue attenuation in posterior mediastinum. Lung bullectomy and mediastinal tumor resection under VATS was performed. A blue-red tumor 4 cm in diameter was resected en bloc. Pathological examination showed its composition of mature adipose tissue and hematopoietic tissue. Diagnosis was extra-adrenal myelolipoma. No recurrent nor abnormality was found in 8 months since surgery.

Endoscopy↗

PubMed1999

Coronary ectasia in familial hypercholesterolemia: histopathologic study regarding matrix metalloproteinases.

A 39-year-old male heterozygous familial hypercholesterolemia patient with marked ectasia over the entire coronary artery tree had been treated with several kinds of lipid-lowering single or combined drug therapies using clofibrate, compactin, cholestyramine, probucol, and pravastatin, and LDL-apheresis. During the 19-year follow-up, he suffered myocardial infarction three times and some of the ectatic coronary segments became enlarged, others narrowed, and one of them occluded in spite of the treatment. At the age of 58, he died after a fourth cardiac attack and subsequent cardiogenic shock. The autopsy indicated that his three coronary arteries showed diffuse ectatic changes and the largest lumen diameter of the left anterior descending artery was 25 mm, of the circumflex artery 12 mm, and of the right coronary artery 13 mm. The ectatic artery wall was not thick and the major part of the lumen was occupied by organized thrombi. Microscopic examinations showed that the larger the diameter of the lumen, the more severe the structural damage of the intima and tunica media and the larger the number of infiltrated cells, including lymphocytes, macrophages, and plasma cells. Immunoreactivity against matrix metalloproteinase (MMP)-1, and MMP-2 was observed in smooth muscle cells, macrophages, lymphocytes, and endothelial cells of the vasa vasorum or neovasculature. MMP-9 immunoreactivity was also localized in intimal foamy macrophages and round cells (macrophages and lymphocytes) of the media and adventitia. MMP-1 increased with the lumen diameter of the ectatic arteries. The ratio of immunoreactivity against both MMP-2 and MMP-9 to that against tissue inhibitor of metalloproteinase (TIMP)-2 also increased with the lumen diameter, but it no longer increased when the diameter was over 10 mm. These observations suggest that the MMP-TIMP system appears to play a significant role in the development of coronary ectasia

Adult↗

PubMed1998

Long-term efficacy of low-density lipoprotein apheresis on coronary heart disease in familial hypercholesterolemia. Hokuriku-FH-LDL-Apheresis Study Group.

Familial hypercholesterolemia (FH) is characterized by severe hypercholesterolemia and premature coronary heart disease (CHD). The lower the plasma cholesterol level, the more likely it is that CHD can be prevented or retarded; aggressive cholesterol-lowering therapies may be indicated for FH patients with CHD. This study describes the long-term (6 years) safety and efficacy of intensive cholesterol-lowering therapies with low-density lipoprotein (LDL) apheresis in heterozygous FH patients with CHD. One hundred thirty heterozygous FH patients with CHD documented by coronary angiography had been treated by cholesterol-lowering drug therapy alone (n=87) or LDL apheresis combined with cholesterol-lowering drugs (n=43). Serum lipid levels and outcomes in each treatment group were compared after approximately 6 years. Both treatment groups had significant reductions in serum cholesterol, LDL cholesterol, and high density lipoprotein cholesterol levels. LDL apheresis significantly reduced LDL cholesterol levels from 7.42+/-1.73 to 3.13+/-0.80 mmol/L (58%) compared with group taking drug therapy, from 6.03+/-1.32 to 4.32+/-1.53 mmol/L (28%). With Kaplan-Meier analyses of the coronary events including nonfatal myocardial infarction, percutaneous transluminal coronary angioplasty, coronary artery bypass grafting, and death from CHD, the rate of total coronary events was 72% lower in the LDL-apheresis group (10%) than in drug therapy group (36%) (p=0.0088). It is concluded that LDL-apheresis is effective as treatment of CHD in FH heterozygotes, and may become the therapy of choice in severe types of FH.

Aged↗

PubMed1998

Clinical efficacy and safety of cerivastatin in the treatment of heterozygous familial hypercholesterolemia.

Patients with heterozygous familial hypercholesterolemia are at especially high risk of premature coronary artery disease and usually require aggressive long-term lipid-lowering drug therapy to decrease plasma low-density lipoprotein (LDL) cholesterol concentrations to normal levels. In the present study, the lipid-lowering effects of cerivastatin in combination with cholestyramine and probucol were investigated in 20 patients with heterozygous familial hypercholesterolemia over a 20-week treatment period. After an initial 4-week treatment with once-daily 0.2 mg cerivastatin, serum total cholesterol and LDL cholesterol levels had decreased by a significant 22% and 25%, respectively (p <0.01). The addition of 8 g/day cholestyramine or 1 g/day probucol to ongoing cerivastatin therapy produced further significant reductions in total cholesterol of 16% and 16%, respectively, and in LDL cholesterol of 22% and 15%, respectively (p <0.01), over the 12-week combination therapy period. The potent lipid-lowering effects of combined treatment were accompanied by excellent toleration of study drugs. Only 2 patients experienced gastrointestinal side effects associated with cholestyramine therapy. There was no evidence of any abnormalities in creatine phosphokinase in either treatment group and only 2 patients exhibited minor increases in hepatic transaminases. This study has shown that cerivastatin can be safely combined with either cholesytramine or probucol to provide a safe and highly effective hypolipidemic treatment regimen for patients with heterozygous familial hypercholesterolemia.

Adult↗

PubMed1998

Low-density lipoprotein receptor genotype-dependent response to cholesterol lowering by combined pravastatin and cholestyramine in familial hypercholesterolemia.

We compared the effects of cholesterol-lowering therapy on 2 patient groups genetically defined as heterozygous for familial hypercholesterolemia (FH), 5 with a deletion of exon 15 (FH(Tonami-1)), and 7 with a point mutation at codon 664 (FH(Kanazawa-2)). There were significant differences in both serum and low-density lipoprotein cholesterol reductions between the 2 groups after combination therapy with pravastatin and cholestyramine, and the overall effect of genotype on serial changes in both was significant.

Adult↗

PubMed1998

Enzyme immunoassay for cholesteryl ester transfer protein in human serum.

We developed a new simple sandwich-type enzyme immunoassay to measure cholesteryl ester transfer protein (CETP) mass in human serum. In assay validation, Intra- and Inter-assay coefficients of variation were 2.7 to 5.7% and 2.2 to 12.2%, respectively. There was no cross-reactivity with various lipoproteins (apo A-I, apo A-II, apo B, apo C-III). A good correlation between CETP mass and CETP activity (n = 46, correlation coefficient = 0.88) was observed. This assay provided a specific and reproducible method for measuring CETP mass in samples. The average value of CETP in the normal sera of 41 males was 1.8+/-0.6 microg/ml (mean+/-S.D.) and that of 37 females was 2.0+/-0.5 microg/ml. In the study of patients with the CETP gene mutation (Int 14A and D442G), our results on the value of plasma CETP mass reflected to genetic CETP deficiency. In conclusion, this assay for CETP mass in human serum may be a useful tool for clinical investigations involving lipid metabolism related to disease.

Adult↗

PubMed1998

Correlation between magnetic resonance imaging and histopathology of an amputated forearm after an electrical injury.

A 53-year-old man sustained a 50 Hz, 60 kV electrical injury. The current flowed between his right hand and both feet. There was necrosis of the distal portion of the right forearm, and the fourth and fifth toes on the right foot. The skin on the amputated right upper extremity appeared normal except for an ulcer in the antecubital fossa and some blister scars. However, most of the muscles of the arm at the elbow were necrosed and partially replaced by fatty tissue or fibrosis. These necrotic areas corresponded to minimally increased signal intensities on T1-weighted MRI, and high signal intensities on T2-weighted images. MRI may be employed to predict amputation level after electrical injury.

Adult↗

PubMed1998

Hepatic perfusion changes after transcatheter arterial embolization (TAE) of hepatocellular carcinoma: measurement by dynamic computed tomography (CT).

We observed the hemodynamic changes at the level of the hepatic parenchyma induced by transcatheter arterial embolization (TAE) for hepatocellular carcinoma in 22 patients. TAE was performed by administration of a mixture of iodized oil, adriamycin, and mitomycin C, followed by injection of gelatin sponge particles (1-mm pieces). Perfusion measurements (arterial and portal) were done by dynamic computed tomography (CT). Arterial perfusion was increased two to six days after TAE (0.146 +/- 0.073 ml/min/ml, P < 0.0002) compared with that before TAE (0.064 +/- 0.039), but decreased again one month after TAE (0.086 +/- 0.038). Portal perfusion was decreased two to six days after TAE (0.541 +/- 0.180, P < 0.001) compared with that before TAE (0.733 +/- 0.263) and was grossly unchanged one month after TAE (0.651 +/- 0.214). We suspected that these perfusion changes were due to acute inflammatory responses. Quantification of tissue perfusion by dynamic CT was useful for studying hemodynamic changes after TAE.

Aged↗

PubMed1998

Isolation and chemical composition of the sheath of Sphaerotilus natans.

A sheathed bacterium, Sphaerotilus natans, was cultured with vigorous shaking in a medium containing peptone. Then the biomass was harvested and treated with lysozyme, sodium dodecyl sulfate, and protease. With treatment, 1.6 mg of sheaths was obtained from 15 mg of biomass. For the preparation of sheaths of high purity, cultivation must be in the absence of glucose with sufficient aeration to prevent poly(3-hydroxybutyrate) accumulation. Carbohydrate (54.1%), protein (12.2%), and lipid (1-3%) were detected in the sheaths by colorimetric reactions and solvent extraction. Gas-liquid chromatography showed glucose and galactosamine to be present in the molar ratio of 1:4. The most abundant amino acids in the sheath protein were glycine (49.2 mol%) and cysteine (24.6 mol%). The sheaths were resistant to agents that reduce disulfide bonds (dithiothreitol and 2-mercaptoethanol) and to protease. However, sheathes were degraded completely by hydrazine, and a heteropolysaccharide composed of glucose and galactosamine (1:4) was released. The weight-average molecular weight of the polysaccharide was estimated to be 1.2 x 10(5) by gel filtration chromatography with a low-angle laser-light scattering photometer and a rotation index detector. A ladder of 1.5-kDa peptides separable by sodium dodecyl sulfate gel electrophoresis was obtained by partial hydrolysis of sheaths, suggesting the sheath protein has repeating units of 1.5 kDa.

Amino Acids↗