Biomedical subjects
Publications and source records attributed to K Kaneda.
The case of a 56-year-old male with a schwannoma in the right psoas muscle is reported. The tumour was extirpated by the retroperitoneal approach, which afforded direct access to this lumbar paraspinal lesion.
This paper evaluates the failure and wear properties of the alumina ceramic posterior cruciate condylar total knee prosthesis, and reports the preliminary clinical results of this prosthesis. Thirteen sets of the alumina ceramic prostheses were used for destruction and wear tests. The average ultimate load in the static destruction tests showed 2.63 x 10(4) Newtons in the femoral component, and 1.28 x 10(4) Newtons in the tibial component. The average ultimate energy in the impact destruction tests showed 22.1 Joules in the femoral components, and 20.3 Joules in the tibial components. The wear test demonstrated that the average depth of wear was 0.04 mm in the alumina ceramic prostheses, and 0.20 mm in the Vitallium prostheses. Observation of the UHMWPE wear surface with a scanning electron microscope indicated many deep scratches and a scooped concave lesion in the Vitallium prostheses; there were few deep scratches in the alumina ceramic prostheses. Thirty patients underwent 32 total knee arthroplasties using the alumina ceramic posterior cruciate condylar prosthesis between 1988 and 1990. The results were evaluated as excellent for 59%, good for 28%, fair for 10%, and poor for 3%. Critical roentgenographic review demonstrated no cases of loosening or sinking after arthroplasties using the alumina ceramic prosthesis. Radiolucent lines were observed only in 4 knees (12%) cases. All were observed around the tibial components, but were less than 1 mm in thickness. The frequency of the radiolucent lines is less than that observed in the Vitallium prosthesis at the same followup period. The alumina ceramic posterior cruciate condylar prosthesis may have sufficient durability and excellent wear properties for low friction total knee arthroplasty.
A fibrous collagen membrane (FCM) made of crosslinked reconstituted collagen fibers was applied as a carrier of BMP. The effectiveness of FCM as a BMP carrier was compared with conventionally used insoluble bone matrix (IBM). Partially purified BMP was obtained from a guanidine HCl extract of bovine bone after a three-step chromatographic procedure. The BMP fraction was combined with FCM or IBM and implanted subcutaneously in the back of rats. Bone and cartilage formation were determined by radiographic, histologic, and biochemical analyses after removal at 1, 2, 3 and 4 weeks. After 2 weeks, bone and cartilage formation were evident histologically in IBM-BMP and FCM-BMP. In IBM-BMP, cartilage was formed in the area of presumptive bone. On the other hand, in FCM-BMP, cartilage formation occurred in the space between the fibers of fiber-bundles, while on the surface of the fibers bone formation started independently. Biochemically, the most noteworthy difference between FCM-BMP and IBM-BMP was the marked increase in type II collagen content in FCM-BMP, which contrasted with its decrease in IBM-BMP at 3 weeks. This study demonstrated that FCM definitely functioned as a BMP carrier that led to bone and cartilage formation at distinct sites. Therefore, we conclude that BMP could induce differentiation of immature cells preferentially into either osteogenic cells or chondrocytes depending upon the nature of the carrier which provides the environment for cell differentiation.
A 63-year-old woman underwent double (aortic and mitral) valve replacement in February, 1987. Thirty days later, purulent drainage developed at the sternotomy incision with high fever. Wound cultures revealed staphylococcus aureus. She was treated by local wound care with antibiotics. About one month later, she had a satisfactory wound healing. But three cutaneous fistulas with discharge emerged at the sternotomy incision in November (9 months later) and the cultures grew the same species. The fistulogram showed the communication between these tracts and the mediastinum. The diagnosis of chronic sternal osteomyelitis and anterior mediastinal abscess was made. At first the resection of the xiphoid process and the mediastinal drainage were carried out in March, 1988. Inspite of this procedure, she still had persistent purulent discharge. Then, en bloc excision of the infected sternum and the adjacent costal cartilage were performed in April. The defect was obliterated with the bilateral pectoralis major muscle flaps. After the radical operation, her wound was completely healed, even though the ventilatory support was needed for 24 days because of flail chest due to the anterior chest wall instability. Now she has been free from recurrence for four years. Total sternectomy and pectoralis major muscle plombage seem to be a very effective management in chronic sternal osteomyelitis.
We followed the course of 20 patients who underwent aortic valve plasty (AVP) combined with mitral valve surgery for rheumatic mild aortic valve disease in association with severe mitral valve disease. At operation, all patients underwent aortic leaflet slicing with a knife, and aortic commissurotomy were performed additionally in 10 patients. After surgery, the degree of aortic valve regurgitation and the amplitude of aortic leaflet motion were assessed chronologically, using ultrasound cardiography. One month after surgery, all but one patients showed a reduction in regurgitation to degree I or less. From the third post-operative year, however aortic valve regurgitation tended to increase again. However, the post-operative degree of regurgitation was observed not to be severer than the pre-operative degree of regurgitation, and no patients showed aggravation of aortic valve regurgitation attributable to exacerbation of mitral valve disease. We divided the patients into two groups according to improvement of aortic valve regurgitation. In the group where the degree of regurgitation returned to the pre-operative one, the degree of amplitude of leaflet motion began to reduce from the third post-operative year and was nearly equal to the pre-operative one at the fifth post-operative year. The results of this study can be summarized as follows: 1. From the third post-operative year, aortic regurgitation was aggravated and aortic valve motion amplitude decreased. 2. The number of sliced valve leaflets and incised commissures did not correlate well with the post-operative reduction in regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)
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We have compared the value of magnetic resonance imaging (MRI) with computed tomography (CT) in assessing the extent and the localization of osteosarcomas. Twenty patients were examined by both systems, and the results related to the clinical and histological findings. While both investigations are valuable, MRI may be more useful for defining the local extent of an osteosarcoma.
The clinical presentations and radiological features of scoliosis accompanying syringomyelia were analyzed in 14 cases of syringomyelia associated with a in 14 cases of syringomyelia associated with a Chiari malformation in children. Scoliosis was the initial symptom in 11 out of 16 patients (64%) with syringomyelia and present in 14 (88%) at the initial examination. The scoliosis associated with syringomyelia was characterized by a higher incidence of a single curve (6 cases, 43%) and convexity to the left (7 cases, 50%) than seen in idiopathic scoliosis. The syrinx was shifted to the convex side of scoliosis on the axial section at the middle or lower thoracic level in patients with a single curve, and at the cervical or upper thoracic level in patients with a double curve. The authors think that the scoliosis develops in children as a result of damage done to the anterior horn, which innervates the muscles of the trunk, by an asymmetrically expanded syrinx.
Experience with infected pseudarthrosis with segmental osseous defect, treated by debridement and microvascular bone transfer, is reported. Fourteen patients form the basis for the study, including 12 males and two females. Patient age at the time of operation averaged 35.1 years. Follow-up averaged 52 months. The affected site included tibia (10), femur (2), and ulna (2). A total of 15 vascularized bone graft transfers were carried out for the 14 patients, with the donor bone fibula (8) and ilium (7). Bony union was ultimately obtained in all patients. In 11 patients, primary union was obtained at both ends of the transferred bone segment. In the remaining three patients, a secondary procedure, consisting of onlay nonvascularized bone autografting at one end of the vascularized transferred bone segment, was required to obtain union. Recurrent infection following union occurred in one patient. One of the two patients with active osteomyelitis at the time of vascularized bone transfer had complications from recurrent sepsis, leading to the authors' caveat that vascularized bone transfer should be deferred until such time as sepsis is inactive. Criteria used in this series for determining inactive sepsis (absence of sinus tracts, negative bacterial cultures, negative c-reactive protein, and a sedimentation rate of less than 15 mm per hour) seem appropriate. The study suggests that vascularized bone transfer is a useful procedure for the treatment of infected segmental osseous defects of long bones, of more than 3 cm extent and one month or more after inactive sepsis.
The physical evaluation and exercise program of trunk muscles in patients with chronic low-back pain (CLBP) is still controversial. Many studies have been performed in the isometric and/or concentric contraction mode. Few data, however, have been reported on trunk-muscle strength during eccentric contraction, which plays a significant role in functional activities. To evaluate whether trunk-muscle strength on eccentric contraction could be applicable to the assessment and exercise of the patients with CLBP, trunk strength was measured in 20 healthy men and 16 healthy women, as well as 15 male and 10 female patients with CLBP. Maximum voluntary concentric and eccentric strength was measured during attempted flexion and extension in a seated position. In the healthy subjects, the maximum torque of extensors was greater than that of the flexors during both concentric and eccentric contraction (p less than 0.05). In flexors and extensors, maximum torque exerted on the eccentric contraction was always greater than that on the concentric contraction (p less than 0.05). Although strength was likely to be weaker in the patients with CLBP than in the healthy subjects, there were no statistical differences between the two groups. In terms of the flexor/extensor ratio of maximum torque, there were also no statistical significances between the two groups in either contraction mode. In the flexors, correlation coefficient (r) between concentric and eccentric torque was 0.84 for the healthy subjects and 0.48 for the CLBP subjects (p less than 0.05). In the extensors, the coefficient was 0.90 for the healthy patients and 0.71 for the CLBP patients.(ABSTRACT TRUNCATED AT 250 WORDS)
In order to clarify the pathomechanism of thoracolumbar burst fractures and to evaluate the influence of disc degeneration and bone mineral density, a biomechanical study was performed using cadaveric spines. Eleven motion segments of thoracolumbar spines from human cadavers were compressed vertically until a fracture occurred. In addition, bone mineral density and degree of disc degeneration were determined for each specimen. Compression of 7 of 11 specimens resulted in the typical burst fracture characterized by retropulsion of a bony fragment into the spinal canal and an increase of the interpedicular distance. All seven specimens showed disruptions of the middle end plate and disc materials in the vertebral body. The fracture line was located between the middle of the end plate and the middle of the posterior wall cortex. No burst fractures were seen in the specimens with severely degenerated discs and osteoporosis. In order to confirm the stress state in a vertebra that induces the burst fracture, finite element analysis of one motion segment was also carried out under the same mechanical conditions as the experiments in this study. As a result of calculation for the healthy disc, the highest stresses under axial compression were concentrated in the following areas: the middle of the end plate, the cancellous bone under the nucleus pulposus, and the middle of the posterior wall cortex. This implies that the above regions are more vulnerable to vertical compressive load. In the analysis of specimens with severely degenerated discs, stresses were very low at the end plate and cancellous bone under the nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)
Twenty-two patients with neurologic deficit due to delayed posttraumatic vertebral collapse after osteoporotic compression fractures of the thoracolumbar spine underwent anterior decompression and reconstruction with bioactive Apatite-Wollastonite containing glass ceramic vertebral prosthesis and Kaneda instrumentation. Eighteen patients previously had minor trauma that resulted in a mild vertebral compression fracture without any neurologic involvement and were either conservatively treated or not treated at all. Four had no history of back injury. The preoperative neurologic status was incomplete paralysis in all patients. The average age at surgery was 66 (53-79) years. The average follow-up was 34 (20-58) months after surgery. All patients had returned to their daily living with neurologic recovery and stable spine. This type of anterior procedure is effective in the osteoporotic patients and there was a very low incidence of instrumentation failure and very low morbidity.
Cyclic axial compression-tension tests and cyclic torsional tests were performed on ten fresh human L4-5 functional spinal units to investigate the structural effects of the posterior elements on the mechanical properties of L4-5 functional spinal units. The stiffness of the functional spinal unit increased with the increase of displacement under every loading. This was same in the intact functional spinal units and the functional spinal units after removal of each posterior element, respectively. All the posterior elements contributed to the compressive, tensile, and torsional stiffness of L4-5 functional spinal units. The apophyseal joints had a significant effect on the compressive and torsional stiffness. The effect of the apophyseal joints on the torsional stiffness became greater according to the extent of displacement, whereas their effect on the compressive stiffness was constant. The posterior ligaments (supraspinous and interspinous ligaments) had a significant effect on the tensile stiffness.
To clarify the morphological changes in renal proximal tubules at the onset of diabetic nephropathy, we observed 177 biopsy samples from patients with Non-Insulin-Dependent Diabetics (NIDDM) using light and electron microscopy. Group I had no proteinuria (p.u.), group II had p.u. < or = 0.5 g/day, group III had p.u. > 0.5 g/day, group IV had serum creatine level (Cr) > 1.5 mg/dl. Twenty age-matched normal patients and 80 patients with IgA nephropathy were used as controls. In groups I and II, the following features were significantly different from those in the controls: spherical enlargement of mitochondria (MT) in proximal tubule cells, hypertrophy of proximal tubule cells and their nuclei, and thickening of both the proximal tubule basement membrane (TBM) and the glomerular basement membrane (GBM). Among the histological changes observed in group I, the thickness of the GBM and TBM indicated that the disease would lead to diabetic nephropathy. MT enlargement was positively correlated with nuclear and cytoplasmic enlargement of the proximal tubule cells in diabetic patients (p < 0.05), but was not correlated with other morphological changes or disease prognosis. Glomerular nodular lesions, glomerular sclerotic change, and cortical tubulointerstitial fibrosis became evident in groups III and IV. From the above, we concluded that MT enlargement and thickening of the TBM are possible causes of reduced active transport in the proximal tubules, causing microalbuminuria in diabetics, and initial impairment of post-tubule transport.
To clarify the ultrastructural changes in renal proximal tubules causing microalbuminuria in the early stage of diabetic nephropathy, three different groups of rats were prepared: rats with streptozotocin (STZ)-induced diabetes given no treatment (DMut; n = 7), rats with STZ-induced diabetes treated with insulin (DMt; n = 7), and non-diabetic rats injected with citrate buffer (control; n = 7). In each group, the laboratory findings, ATP content of the renal cortex, and the size of proximal tubule cells and their nuclei and mitochondria (MT) were determined. In two weeks after the start of the study, MT in renal proximal tubules showed diffuse enlargement in the DMut group as compared with those in the control group. Renal cortical ATP content, fractional sodium excretion (FENa), urinary excretion of beta 2-microglobulin and albumin were also increased significantly in the DMut group relative to the controls. In the DMt group, most of the examined parameters returned almost to normal. There were positive correlations between each of the following parameters: hyperglycemia and MT enlargement, MT enlargement and increased cortical ATP content, increased cortical ATP content and increased FENa, increased FENa and increased urinary excretion of beta 2-microglobulin and albumin. On the basis of these results, we conclude that mitochondrial enlargement, resulting from disturbed metabolism of ATP, may reduce active transport in renal proximal tubules, which, in turn, may impair reabsorption in the tubules. This would cause urinary excretion of low-molecular-weight proteins and microalbumin in the early stage of diabetic nephropathy.
The mechanical and structural properties of the patellar tendon fascicle-bone units of rabbit knees were determined by tensile tests, particularly focusing on their local differences. There were no significant differences in the strains measured by a video dimension analyzer among the proximal, middle, and distal regions of the central portion of tendon. The mechanical properties of the medial portion agreed well with those of the central portion. However, significant differences were observed in the tensile strength between the lateral and the other two portions: the tensile strength of the lateral portion was about 16 percent larger than those in the other portions.
Serrawettin W2, a surface-active exolipid produced by nonpigmented Serratia marcescens NS 25, was examined for its chemical structure and physiological functions. The chemical structure was determined by degradation analyses, infrared spectroscopy, mass spectrometry, and proton magnetic resonance spectroscopy. Serrawettin W2 was shown to be a novel cyclodepsipeptide containing a fatty acid (3-hydroxydecanoic acid) and five amino acids. The peptide was proposed to be D-leucine (N-bonded to the carboxylate of the fatty acid)-L-serine-L-threonine-D-phenylalanine-L-isoleucine (bonded to the 3-hydroxyl group). By examining the effects of isolated serrawettin W2 on serrawettinless mutants, this lipopeptide was shown to be active in the promotion of flagellum-independent spreading growth of the bacteria on a hard agar surface. The parent strain NS 25 formed a giant colony with a self-similar characteristic after incubation for a relatively long time (1 to 2 weeks), similar to other fractal colony-producing strains of S. marcescens (producers of the different serrawettins W1 and W3). On a semisolid medium that permitted flagellum-dependent spreading growth, an external supply of serrawettin W2 accelerated surface translocation of a serrawettinless mutant during a short period (12 h) of observation. In contrast, bacterial translocation in the subsurface space of the semisolid agar was not enhanced by serrawettins. Thus, the extracellular lipids seem to contribute specifically to the surface translocation of the bacteria by exhibiting surfactant activity.
The effect of taxol, which is a microtubule stabilizer, was examined in a model of acute edematous pancreatitis induced in rat by the administration of caerulein. Prophylactic administration of taxol ameliorated inhibition of pancreatic secretion, increased level of serum amylase, pancreatic edema, and histological alterations in this model. Immunofluorescence studies revealed that taxol stabilized the arrangement of microtubules by the action of promoting tubulin polymerization and prevented inhibition of pancreatic digestive enzyme secretion. In isolated rat pancreatic acini, taxol reversed the inhibition of amylase secretion induced by supramaximal concentrations of cholecystokinin octapeptide and did not affect the binding of cholecystokinin octapeptide to its receptor. The results obtained in this study suggest that microtubule disorganization is the initiating event in caerulein-induced pancreatitis and that the inhibition of pancreatic digestive enzyme secretion by interfering with intracellular vesicular transport due to microtubule disorganization causes caerulein-induced pancreatitis.