Clinical and biochemical phenotype of the MELAS mutation.
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Biomedical subjects
Publications and source records attributed to R Nakamura.
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Asparagine-linked oligosaccharides of duck ovomucoid were released quantitatively from the protein by digestion with glycoamidase A (from almond), the reducing ends of the oligosaccharide chains thus obtained were aminated with a fluorescent reagent, 2-aminopyridine, and the mixture of pyridylamino derivatives of the oligosaccharides was separated using two different types of high performance liquid chromatography (HPLC) on a reversed phase column and an amide adsorption column. More than sixteen different oligosaccharides were separated and the structures were characterized by a combination of the 2-dimensional sugar mapping technique using HPLC, exoglycosidase digestion, and proton nuclear magnetic resonance measurements (1- and 2-dimensional). Furthermore, the HPLC profile of duck ovomucoid oligosaccharides was compared with previously reported profiles obtained from quail and chicken ovomucoids.
The present study was done to evaluate the effect of short-term dietary therapy on 148 dyslipidaemic children (24 familial hypercholesterolaemia, 105 non-familial hypercholesterolaemia and 19 hypertriglyceridaemia), detected by mass screening in children at 18 months of age. In the model diet used for treatment, 15% of the total calories were obtained from protein, 27% from fat and 57% from carbohydrate. Cholesterol intake was set at < 200 mg/day and the ratio of polyunsaturated to saturated fatty acid (P/S ratio) was 1.2. When compared to the composition of the diet ingested by the dyslipidaemic children, only the P/S ratio changed from 0.7 to 1.2. During 12 months treatment, levels of total cholesterol, low density lipoproteins cholesterol and apoB decreased by 10%-15% in children with familial and non-familial hypercholesterolaemia. There was no significant change in the levels of high density lipoproteins. In 19 children with hypertriglyceridaemia, the intake of carbohydrate was limited to 55% of the total calories consumed and after 12 months of treatment, triglyceride levels reverted to normal. Throughout the study period, approximately 70% of the children on this dietary therapy were seen in our clinics every 3-6 months and physical development was within normal ranges. These results, taken together, indicate that dietary therapy can be effective for correcting dyslipidaemia, even in young children.
Changes in carpal alignment following radial osteotomy were studied in 30 patients with Kienböck's disease. The carpal height ratio and carpal-ulnar distance ratio were significantly less in wrists with Kienböck's disease than unaffected wrists. This observation implies proximal-ulnar translation of the capitate. In addition, the lunate-covering ratio increased significantly, reflecting radial translation of the lunate. Radial osteotomy corrected ulnar translation of the capitate and increased the radial translation of the lunate, thus increasing the lunate-covering ratio. The increased lunate-covering ratio is believed to increase the area of distribution of the axial load through the lunate by increasing the contact area with the radius. The satisfactory clinical outcome of radial osteotomy is believed to be due to this effect on carpal alignment.
50 patients with scaphoid non-union were treated by open reduction, anterior wedge bone grafting and internal fixation using the Herbert screw. Intra-operative image intensifier control enabled us to insert the screw into the scaphoid accurately. An excellent or good functional outcome was less likely when more than 5 years had elapsed since injury, the non-union was in the proximal third, when sclerosis of the proximal fragment was present, and when reduction of carpal and scaphoid deformity was unsatisfactory. These four factors are believed to be the primary determinants affecting the functional results of the surgical treatment of scaphoid non-union, even when bony union is achieved.
The incidence of Heberden's nodes was determined in three groups of Japanese women with different occupations to investigate the role of work-load in their pathogenesis. School cooks (n = 260), each of whom prepared 150 to 450 lunches daily, pre-school cooks (n = 222), each of whom prepared 30 to 80 lunches daily, and municipal employees (n = 298) underwent physical examination and X-ray of the hand if pathology was present. The incidence of Heberden's nodes and X-ray incidence of osteoarthritis was 19.2% and 13.5%, 8.6% and 5.4%, 5.9% and 2.0% among school cooks, pre-school cooks and municipal workers, respectively. The incidence of Heberden's nodes and osteoarthritis was significantly higher among school cooks. These findings support the concept that work-load is an aetiological factor in the pathogenesis of Heberden's nodes and also support Radin's hypothesis that women's daily work pattern explains the increased incidence of DIP joint osteoarthritis in women.
Two cases of fracture of the radius treated by pinning resulted in severe wrist joint deformity due to premature closure of the epiphysial growth plate. Inappropriate pinning through the physis damaged the growth plate in both cases. They were treated by bone bridge resection with free fat interposition. The bone bar resection was effective in correcting the wrist joint deformity, and bone growth was expected without bone grafting.
Contralateral unaffected wrists from 41 males with Kienböck's disease were compared with wrists from 66 normal males. From X-rays, various features of the lunate and radius were measured. In patients with Kienböck's disease, the lunate tended to be smaller and inclined more radially than in normal subjects and the radial inclination was flatter. Discriminant analysis showed that 85% of the unaffected contralateral wrists in patients with Kienböck's disease and 74% of the wrists in normal subjects were accurately discriminated to their respective groups. It may be possible to identify subjects who are at risk for Kienböck's disease prior to onset using discriminant analysis.
Biomechanical analysis of force transmission through the lunate was performed with the use of a two-dimensional mathematical model to evaluate the usefulness of radial wedge osteotomy, a procedure that decreases radial inclination, in the treatment of Kienböck's disease. The forces acting on the carpal bones were compared before and after radial wedge osteotomy in 29 patients with Kienböck's disease. The average osteotomy angle was 9.6 degrees. The total force through the lunocapitate joint at the midcarpal level was decreased by 23%, while the total force through the radiolunate and ulnolunate joints at the radioulnocarpal level was decreased by 10% and 36%, respectively. These changes correlated directly with the osteotomy angle and demonstrate decompression of the lunate by radial wedge osteotomy.
Direct cytotoxicity of black-pigmented anaerobic rods was studied on the confluent monolayer of human gingival fibroblasts in vitro. Only strains of Porphyromonas gingivalis caused morphological alteration (cell-rounding) and notable depression of viability of fibroblasts. To determine the location of the cytotoxicity, bacterial surface components, i.e., outer membrane, lipopolysaccharide, fimbriae and outer membrane vesicles were prepared from P. gingivalis and their cytotoxicity was assessed. Among these preparations, only outer membrane vesicles are supposed to have high affinity to human gingival fibroblasts, and the cytotoxicity of outer membrane vesicles was found to be much stronger than that of the other constituents. This cytotoxic factor seemed to consist largely of protein and to be associated with the enzyme activity of outer membrane vesicles. The effects of some protease inhibitors and L-cysteine on the cytotoxicity of outer membrane vesicles suggest that the mechanism of cell-rounding is different from that of cell death.
Insulin chain B, containing each one arginyl and lysyl residue in its peptide chain, inhibited hemagglutination by Porphyromonas gingivalis. To determine the further inhibitory profile, chain B was digested into 4 fragments by protease, which was contained in the preparation of hemagglutinin from P. gingivalis. Identification of each fragment by the amino acid analysis revealed that the chain was cleaved at the carboxyl site of arginyl and/or lysyl residues, but one fragment contained citrulline instead of arginine at its carboxyl terminal. This citrulline might have originated from arginine by an arginine deiminase-like enzyme of P. gingivalis. Only one fragment that contained the arginyl residue exhibited inhibitory activity on hemagglutination, but it was considerably weakened compared with that of the intact chain B. The difference in the inhibitory activity seemed to depend on the position of an arginyl residue in the peptide; this was also confirmed using several derivatives of bradykinin. The present result suggests that the internal arginyl residue in a peptide chain may be critical for the inhibition of the hemagglutination by P. gingivalis.
Although the accumulation of cholesterol in macrophages appears to be an initial step in atherogenesis, low-density lipoprotein (LDL), a major risk factor for atherosclerosis, does not promote cholesterol accumulation in macrophages in its native form. On the other hand, apolipoprotein (apo) A-I-containing lipoprotein removes cholesterol from cholesterol-loaded macrophages (foam cells) and prevents cholesterol from accumulating in the cells. We examined the effect of LDL on cholesterol removal by two species of apoA-I-containing lipoproteins, one containing only apoA-I (LpA-I) and the other containing apoA-I and apoA-II (LpA-I/A-II). When foam cells were incubated with LpA-I or LpA-I/A-II, cellular cholesterol mass was reduced. In contrast, when LDL was added, the cholesterol-reducing capacities of these lipoproteins were dose-dependently inhibited by LDL. In the presence of LDL, LpA-I and LpA-I/A-II removed free cholesterol preferentially from LDL rather than from the plasma membrane of foam cells. In addition, a fair amount of cellular cholesterol was directly moved to LDL rather than to LpA-I or LpA-I/A-II. The cellular cholesterol that moved to LDL was completely compensated for by the cholesterol influx from LDL to foam cells. Thus, net cholesterol efflux (a combination of influx and efflux) from foam cells was inhibited by LDL. These results, taken together, indicate that LDL may accelerate foam cell formation by inhibiting cholesterol removal from the cells and that elevated levels of plasma LDL may become a risk factor for atherosclerosis by inhibiting the function of LpA-I and LpA-I/A-II at the cellular level.
A new monocytic leukemia cell line (KP-1) was established from a 2-y-old Japanese girl with acute monocytic leukemia. The KP-1 cells were maintained in suspension culture with a doubling time of 96 h. The cells were positively stained with alpha-naphtyl butyrate esterase, but not with naphthol AS-D chloroacetate esterase, myeloperoxidase, and periodic acid-Schiff reagent. Cell surface marker analysis revealed that the cells were CD4, CD11a, CD11c, CD13, CD14, CD18, CD33, and HLA-DR positive. Karyotype analysis revealed near diploidy (47 XX) and a translocation t(11;19) was found. When treated with 12-o-tetradecanoylphorbol 13-acetate, KP-1 cells became tightly adherent, showed the enhanced reactivity for alpha-naphtyl butyrate esterase, and produced several monokines such as IL-1 beta, tumor necrosis factor-alpha, and macrophage colony-stimulating factor. Immunoelectron microscopy demonstrated that the human macrophage scavenger receptor was expressed after 12-o-tetradecanoylphorbol-13-acetate treatment, and the cells accumulated a large amount of cholesterol esters in the presence of acetylated LDL. Compared with another human monocytic leukemia cell line, THP-1, KP-1 expressed scavenger receptor and accumulated cholesterol ester more rapidly in the presence of 12-o-tetradecanoyl phorbol-13-acetate and acetylated LDL. Scatchard analysis using 125I-labeled acetylated LDL revealed a typical saturation curve with an apparent kd of 1.7 x 10(-7) M and 3400 binding sites per cell. KP-1 retained the characteristics of monocyte-macrophage lineage cells and will facilitate the in vitro studies of the pathologic and physiologic roles of scavenger receptors.
We investigated the effects of recombinant human erythropoietin (rHuEPO) therapy on exercise capacity by symptom-limited maximal treadmill exercise testing in 9 patients with coronary artery disease who were receiving maintenance hemodialysis. The initial hemoglobin concentration of 7.9 +/- 0.7 g/dl, (mean +/- S.D.) rose to 10.4 +/- 1.1 g/dl, (p < 0.01) after three months of rHuEPO therapy. The partial correction of renal anemia resulted in a significant increase in exercise duration (from 278 +/- 84 sec to 384 +/- 74 sec, p < 0.01) and maximum pressure-rate product (from 228.3 +/- 50.3 mmHg.bpm/10(2) to 262.8 +/- 40.4 mmHg.bpm/10(2), p < 0.01). The maximum exercise-induced ST segment depression significantly decreased after treatment (from 1.3 +/- 0.5 mm to 0.5 +/- 0.5 mm, p < 0.05). These results suggest that the improvement in maximum coronary oxygen supply exceeded the increased maximum myocardial oxygen requirements after the partial correction of renal anemia by rHuEPO therapy in hemodialysis patients with coronary artery disease.
24 patients with Kienböck's disease were followed with magnetic resonance imaging (MRI) for 1-3 years. 9 patients were treated with radial shortening, 10 with radial wedge osteotomy and 5 patients were treated non-operatively. Signal intensity of the lunate on T1-weighted or T2-weighted images increased postoperatively in all operated on patients, and normal or near-normal signal intensity was observed in 9 patients on T1-weighted images and in 15 patients on T2-weighted images postoperatively. Signal intensity did not increase in any patient treated non-operatively. The postoperative increase in signal intensity on MRI following radial shortening and radial wedge osteotomy presumably is due to revascularization of the lunate.
Between January 1985 and November 1992, 12 patients with renal cell carcinoma involving the inferior vena cava were evaluated and treated at this hospital. In 4 of the 12 patients (33%), the tumors extended into the right atrium. These 4 patients underwent radical nephrectomy with tumor thrombus extraction. Of the 4 patients one had metastases to regional lymph nodes, but no patient had distant metastases. We used a cardiopulmonary bypass and a right atriotomy in all patients for the removal of thrombus under direct vision. We also performed in the intra-operative transesophageal ultrasonography for monitoring of intra-atrial thrombus. The average blood loss during operation was 10,430 ml. One of these patients died in the postoperative period and the other patient died from inferior vena caval emboli without long term sequelae. However, the remaining 2 patients of this group are free of disease, with a mean follow-up of 21 months. Although the numbers are small, these results suggest that patients with intra-atrial tumor thrombus had a worse prognosis than those with other types of vena cava tumor thrombus. One reason for this poor prognosis is due to the complicated surgical management and we believe that a complete removal of tumor thrombus and a complete vascular control are key points of this operation.
Thirty-seven joints in 36 patients with a fractured carpal scaphoid were evaluated by three-phase bone scintigraphy. They were classified into two groups according to their progress. Some were in good clinical condition and some in a non-union condition. Increased blood flow in the radial arteries and ample perfusion on and around the scaphoid bones on blood flow images suggested a good clinical course. The activity and the effectiveness of remodeling correlated well with the degree of scaphoid uptake on blood pool images taken more than seven days after the injury. Scaphoid uptake was more localized or there was almost none on blood pool images in cases with nearly complete recovery while it was amply visualized on static images. Blood pool images were indispensable for analyzing lesions and evaluating the clinical course. Two typical findings of scaphoid fractures were found on both blood pool and static images. One was diffusely increased scaphoid uptake seen in cases with a good clinical course, and the other was decreased uptake at proximal fragments seen in cases with non-union. It is concluded that three-phase bone scintigraphy provides useful information for evaluating the process of scaphoid fractures which cannot be obtained by means of conventional bone scintigraphy.
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