Influence of microscopic surface asperities on the wear of ultra-high molecular weight polyethylene in a knee prosthesis.

The wear of ultra-high molecular weight polyethylene (UHMWPE) in knee and hip prostheses is one of the major factors restricting the longevity of these implants. A number of microscopic scratches caused by various factors were observed on the metallic femoral components of the retrieved knee prostheses with an anatomical design. It appears that microscopic surface asperities caused by this surface damage contribute to increasing and/or accelerating the wear of the UHMWPE tibial insert. In this study, in the first step, microscopic observations and surface roughness measurements of several retrieved metallic femoral components were performed in order to produce simplified two-dimensional (2D) finite-element method (FEM) models of a microscopic surface asperity using roughness parameters. Next, a three-dimensional (3D) microscopic surface profile measurement of the damaged surface of a retrieved metallic femoral component and the reproduction of the femoral component surface were performed in order to produce 3D FEM models of a microscopic surface asperity based on actual measurement data. 2D and 3D elastoplastic contact analyses between a metallic microscopic surface asperity and UHMWPE were also performed in order to investigate the mechanical state and microscopic wear of UHMWPE caused by a metallic microscopic surface asperity. The analytical findings of this study suggest that the aspect ratio, shape ratio, and indentation depth of the microscopic surface asperity have significant influence on increasing and/or accelerating the wear of UHMWPE. Higher aspect ratios, shape ratios, and indentation depths cause higher contact stresses and plastic strains in UHMWPE.

Purulent pericarditis caused by Streptococcus milleri.

Streptococcus milleri was isolated in pure culture from the pericardial fluid of a 42-year-old man with pulmonary tuberculosis. Pericardiectomy had to be done to cure the pericarditis.

Destruxins, cyclodepsipeptides, block the formation of actin rings and prominent clear zones and ruffled borders in osteoclasts.

Bone-resorbing osteoclasts exhibit polarized morphological structures such as actin rings, clear zones, and ruffled borders. To gain insight into the mechanism of bone-resorbing activity of osteoclast and to discover new types of anti-resorptive agents, we have screened for natural compounds that inhibit the bone-resorbing activity of osteoclast-like multinucleated cells (OCLs). Destruxin B (DestB) and E (DestE), cyclodepsipeptides, were found to inhibit pit formation without affecting osteoclast differentiation and survival. Destruxins reversibly induced morphological changes in OCLs in a dose-dependent manner (DestB, 0.2-1 microM; DestE, 0.01-0.05 microM) and inhibited pit formation. Destruxin-induced morphological changes were accompanied by disruption of the actin rings in OCLs. The formation of actin rings in OCLs after adhesion was also inhibited by destruxins. Electron microscopical analysis revealed that destruxin-treated OCLs on dentine slices have no prominent clear zones and ruffled borders. The effective concentrations of destruxins on the morphological changes were almost the same as those that inhibited bone resorption in organ culture system. These results suggest that the anti-resorptive effects of destruxins result from induction of a disorder of the morphological structures in polarized OCLs.

Paralytic ileus due to strongyloidiasis: case report and review of the literature.

We report a rare case of a patient with ileus due to Strongyloides infection that occurred four times within a six-month period. The ileus was improved by treatment with ivermectin and there has not been a recurrence of the symptoms within the last two years.

The effect of humoral and cell-mediated immunity in resistance to systemic Serratia infection.

Protection against experimental Serratia marcescens infection in mice was enhanced by prior injection of formalin-killed or viable bacteria of the same strain. From the first to the fourth week after vaccination, specific immunity was involved in the host defence against systemic serratia infection. The transfer of antiserum specific for S. marcescens increased bacterial clearance from the liver, but did not increase the survival of the mice. Bacterial clearance from the liver was also increased by the transfer of spleen cells from immunised mice, but, again, survival was not increased. However, the transfer of both antiserum and spleen cells from vaccinated mice increased both bacterial clearance from the liver and survival (p less than 0.01). These results suggest an additive effect of humoral immunity and T-cell-mediated immunity in protection against systemic serratia infection.

Characterisation of the external surfaces of Pseudomonas aeruginosa isolated from human blood and respiratory tract.

The surface structures of the cell envelopes of 16 clinical isolates of Pseudomonas aeruginosa were examined by electronmicroscopy with the new fixation technique of freeze-substitution. Two types of structures were observed among the organisms. In one group of strains, mostly isolated from blood, a dense fibrous layer c. 30 nm thick was found around the outer-membrane surface, whereas no such structure was observed in the other group of isolates, most of which were from sputum. Lipopolysaccharides extracted from the isolates with a dense fibrous layer were found by SDS-PAGE to have long O-polysaccharide chains, whereas strains without such a layer mostly had lipopolysaccharides that lacked high mol. wt. O-polysaccharide chains.

Evaluation of cefoperazone in the treatment of bacterial infections in patients with hematological diseases.

This study was conducted as a multicenter trial in 12 institutions in the Kyushu region of Japan. The clinical effects of cefoperazone were evaluated in 101 patients with 112 infections complicated by hematological disease. In about half of the patients, the baseline neutrophil count was below 1,000/mm3. Results were excellent in 23 of 101 cases and good in 48, with an efficacy rate of 70.3%. Cefoperazone alone or in combination with other antibiotics was effective in 60.7% of patients who had not responded to previous antibiotic therapy. No serious side effects attributable to cefoperazone were noted. The results indicate that cefoperazone is a useful antibiotic for the treatment of severe infections in patients with hematological diseases.

Elasto-plastic contact analysis of an ultra-high molecular weight polyethylene tibial component based on geometrical measurement from a retrieved knee prosthesis.

The wear phenomenon of ultra-high molecular weight polyethylene (UHMWPE) in knee and hip prostheses is one of the major restriction factors on the longevity of these implants. Especially in retrieved knee prostheses with anatomical design, the predominant types of wear on UHMWPE tibial components are delamination and pitting. These fatigue wear patterns of UHMWPE are believed to result from repeated plastic deformation owing to high contact stresses. In this study, the elasto-plastic contact analysis of the UHWMPE tibial insert, based on geometrical measurement for retrieved knee prosthesis, was performed using the finite element method (FEM) to investigate the plastic deformation behaviour in the UHMWPE tibial component. The results suggest that the maximum plastic strain below the surface is closely related to subsurface crack initiation and delamination of the retrieved UHMWPE tibial component. The worn surface whose macroscopic geometrical congruity had been improved due to wear after joint replacement showed lower contact stress at macroscopic level.

Adaptive multimode lubrication in natural synovial joints and artificial joints.

To examine the lubrication mechanisms in both natural synovial joints and artificial joints with artificial cartilages, pendulum tests of pig shoulder joints and simulator tests of sliding pairs of a stainless steel spherical component and natural articular cartilage or artificial cartilage have been conducted. Firstly, it was shown in pendulum tests of pig shoulder joints that both concentration of hyaluronic acid or viscosity and adsorbed film formation of proteins and phospholipids exerted a significant effect on frictional behaviour in swinging motion immediately after a loading of 100 N. Under a high load of 1 kN, low friction was observed under wide-ranging viscosity conditions, since a high load similar to body weight probably enhanced the squeeze film effect due to improved congruity. Next, frictional behaviour of sliding pairs in knee joint models, consisting of a stainless steel spherical surface and either specimens of pig tibial cartilage or polyvinylalcohol (PVA) hydrogel, was examined during walking in simulator tests. In these tests, the influences of lubricant viscosity and addition of protein on frictional behaviour were evaluated. For both compliant materials, the appropriate addition of gamma-globulin to sodium hyaluronate (HA) solution maintained low friction and protected rubbing surfaces under thin film conditions. These phenomena are discussed from the viewpoint of adaptive multimode lubrication.

[A case of remarkable effect of clindamycin in nasal septum abscess caused by Streptococcus milleri].

We encountered a 14-year-old male patient with a destructive abscess of nasal septum, caused by Streptococcus milleri. He was successfully treated with Clindamycin in combination with surgical intervention. We emphasized the significance of Streptococcus milleri as a causative agent for abscess formation, and clindamycin should be considered as a first choice of antibiotics against Streptococcus milleri infection.

[Clinical analysis on 127 cases of fungemia in Fukuoka University Hospital between 1984 and 1994].

A clinical analysis on 127 cases out of 140 cases presenting with fungemia at Fukuoka University Hospital between 1984 and 1994 was done. The number of the positive blood cultures during the same period was 1188 and the rate of fungemia was 11.8%. The rates generally increased in recent years, 9.0% (1984-1986), 10.2% (1987-1989) and 13.6% (1990-1994), but decreased after 1992. C. albicans has shown a tendency to decrease while C. parapsilosis and C. glabrata have increased in recent years thus suggesting the effect of the prevalence of intravenous hyperalimentation (IVH) and azole antifungal agents. Only 3.9% of the fungemia were preceded by bacteremia. In addition to the known risk factors for fungemia such as IVH (89.0%) and the antibacterial agents, H2-receptor antagonists were used in 58.3% of the cases. 14 cases of the fungemia were observed during the prophylactic use of antifungal drugs. Therefore, fungemia should always be kept in mind regarding the differential diagnosis for bacteremia when an indwelling venous catheter is used. The prompt extubation of the catheter in addition to the adjustment of the dosage of antifungal drugs in response to the status of the host defense system are thus considered to be important in the treatment of fungemia.

[A case of tuberculous pyothorax after an interval of four years of finishing with the first treatment for pulmonary tuberculosis].

We reported a case of tuberculous pyothorax which developed at four years after finishing with the first treatment for pulmonary tuberculosis. A 50-year-old female was admitted to our hospital with right chest pain. Tuberculous pyothorax was diagnosed by means of polymerase chain reaction (PCR method) of pleural effusion and of histological findings of the pleural section. She was cured by operation, pleural drainage and anti-tuberculous drugs. The bone scincigram of 99mTc revealed accumulation in the right 9th rib, tuberculous empyema might have been a secondary development from osteomyelitis.

[Clinical studies on mycosis especially deep-seated candidiasis in blood disorder patients].

Deep-seated mycosis is prominently increasing as a terminal infection in compromised hosts with malignant blood disorders or malignant tumors. Moreover, localized candidal abscess of visual organs has recently been reported in several laboratories. We investigated the occurrence of deep-seated mycosis in 105 autopsied cases with blood disorders in our clinic from 1980 to 1987. Forty-four of those cases had died of various infections, and 80% of them were fungal infections. More than half of the fungal infections were aspergillosis. Deep-seated candidiasis was recognized in 10 cases, 6 of which were systemic candidiasis, the average duration of neutropenia below 500/mm3 was 19.7 days that of lymphopenia was 36.5 days. Two cases were complicated with GI-tract ulcer, and involved with hepatic candidiasis. On the other hand, in the 4 cases of localized candidial abscess, the duration of neutropenia was 58.5 days and that of lymphopenia was 28.8 days. These four cases were complicated with GI-tract ulcer. Histologically, Candida spp. were recognized at the bottom of the ulcer and invasion by inflammatory cells or tumor cells was found in the portal vein. We surmised that GI-tract ulceration is a very important complication of hepatic candidiasis or liver abscess, and the occurrence of localized candidiasis seems to depend on the duration and severity of neutropenia.

[Ofloxacin in the treatment of infection caused by Salmonella paratyphi A].

We reported a case of salmonellosis treated with ofloxacin (OFLX) which showed excellent clinical and bacteriological effect in a 22 year-old Japanese male with Salmonellosis paratyphi A. He had stayed in India from Sept. 6, 1990 to Oct. 13, 1990. On Oct. 25, 1990, he complained of a high fever and headache. On Oct. 29, he was admitted to our hospital and was diagnosed as Salmonellosis paratyphi A by the blood culture. He was treated with 2.0 g/day of chloramphenicol (CP) for 7 days, but the clinical efficacy was not sufficient. Therefore, we added 900 mg/day of OFLX for 10 days. He was treated successfully with them, the temperature became on the 2nd day. No side effect and no changes of laboratory data were observed and no recurrence was observed clinically and bacteriologically for three months after his discharge.

[A case of Plasmodium vivax malaria with findings of DIC].

We reported a rare case of Plasmodium vivax malaria who showed findings of disseminated intravascular coagulation (DIC). A 50-year-old Japanese male was sent to our hospital with the diagnosis of Plasmodium vivax malaria on the 26th of April, 1990. He had stayed in the Solomon Islands from Oct. 1987 to Dec. 1989, and had febrile episodes during his stay in the island. On April 18, 1990, he complained of a high fever with chills, and showed the same episodes on the 20th, 22th and was diagnosed as malaria. He was treated successfully with the sulfadoxine 500 mg and pyrimethamine 25mg (Fansidar), following the normal temperature on the 4th day and disappearance of malarial parasites in the peripheral blood smear on the 6th day. Interestingly, he had thrombocytopenia and a high titer serum level of fibrin degradation product (FDP) supporting the questionable diagnosis of DIC. Even on the 12th day after improved thrombocytopenia by treatment with Gabexate (FOY), the serum level of FDP, D-dimer and thrombin-nati-thrombin (TAT)III complex still remained at high titer levels. One month later he was readmitted for a relapse of Plasmodium vivax malaria, when he showed thrombocytopenia but the serum level of FDP, D-dimer, TAT III complex and PM.alpha 2 PI complex were normal levels. We concluded that the thrombocytopenia and the high titer of FDP at his first admission was a manifestation of DIC.

[A case of Chlamydia pneumonia and systemic lupus erythematosus (SLE) pleurisy].

A 40-year-old female was admitted with right chest pain. SLE was absent from her past history, although she complained of polyarthralgia in winter. Atypical pneumonia/pleuritis was suspected by chest X-ray film, showing a nodular shadow in the right lower field and moderate pleural effusion. Chlamydia pneumonia was diagnosed by elevated anti-C. psittsci antibody, while characteristics of pleural fluid revealed serositis accompanied by SLE because of the high titered anti-DNA antibody and the low titered complement. She was cured by clarithromycin and subsequent administration of prednisolone and cyclophosphamide.

[Immunodeficiency and carcinogenesis in patients with chronic active Epstein-Barr virus infection].

Three adult patients with chronic active Epstein-Barr virus infection (CAEBV) had high anti-EBV-VCA antibody, positive anti-EA, low anti-EBNA and were associated with systemic lymphadenopathies and immunosuppression. The case 1 and 2 had elevated serum immunoglobulin levels, and recurrent infections, and case 3 showed pancytopenia. These 3 cases developed both EBV and latent membrane protein (LMP) positive malignant histiocytosis, EBV positive but LMP negative plasmacytoma, and EBV negative acute myelogeneous leukemia, respectively. It was suggested that CAEBV belonged to high risk groups for the development of malignant neoplasms. Since HLA of the case 1 and his father was identical, we conducted a in vitro cytotoxicity test using EBV transformed autologous B lymphocytes, K562 cells, and Raji cells to clarify the association of immunosuppression and HLA. The case 1 showed a low level of specific cytotoxicity to autologous EBV transformed B cells, while his parents were negative for the specific cytotoxicity. The patient and his parents developed inducible cytotoxicity to all targets after in vitro incubation of peripheral mononuclear cells with recombinant interleukin 2 (rIL-2) for 7 days. The patient and his mother showed lower enhancement of cytotoxicity, while HLA identical father could induce good cytotoxic activity to all targets as well as normal controls, indicating that a low IL-2 induced cytotoxic activity observed in CAEBV was independent of HLA associated immunoregulation at least in the case 1. Further studies are required to clarify the exact mechanisms responsible for the development of CAEBV.

[An autopsied case of infective endocarditis with cardiac tamponade due to myocardial rupture].

Since it is very rare that cardiac tamponade due to myocardial rupture caused by infective endocarditis, occurs we are reporting this case. A 62 year old man, who had underlying diseases of pneumoconiosis and hypertensive heart disease, visited Chikuho Rosai Hospital complaining of chest oppression and general fatigue on Feb. 7, 1987. He was diagnosed as having ischemic heart disease by electrocardiogram. Two days later, he suddenly had chills and a fever, and the laboratory data showed leukocytosis and a positive C-reactive protein (CRP). The echo cardiogram showed mitral regurgitation (MR) and aortic regurgitation (AR), but neither vegetation nor pericardial effusion was observed. On Feb. 16, he was admitted with shock, and he died the next day. The blood cultures grew gram-positive cocci, respectively. From the clinical symptoms, chest roentgenogram and electrocardiogram, we suspected a cardiac tamponade. On autopsy findings, though coronary arteries were intact, the aortic valves had severe valvular adhesions, calcifications and hypertrophies. The rupture hole was observed in the left ventricles, which was just under the aortic valve through the pericardiac space. It seemed that he died of a cardiac tamponade due to the outflow of blood from this hole. On histopathologic findings of the cardiac wall, gram-positive cocci and many of neutrophils were observed.

[Clinical studies on SM-4300].

Use of SM-4300, which is a newly developed human immunoglobulin preparation for intravenous administration, has clinically been evaluated in the patients with severe or intractable bacterial infections. Of total 13 cases of the admitted patients at the 1st department of internal medicine, faculty of medicine, Kyushu university, 10-pneumonia case were associated with blood diseases like acute myelocytic leukemia (AML) and multiple myeloma (MM), and in addition, with other underlying diseases like lung cancer and bronchiectasis, 1 was prosthetic valve endocarditis, 1 cholecystitis associated with pericarditis and 1 fever of undetermined origin (FUO). SM-4300 of 5 g single bolus or 3 daily doses of 2.5 g per day were infused with chemotherapy drugs preceedingly administered for more than 3 days and the results were evaluated; good in 4, fair 4, poor 2 and unknown 3, and the efficacy rate was 40%. Bacteriologically, the results were decreased in 1, persisted 1 and the majority was unknown. Observed were no side reactions nor the changes in clinical examination variables incurred by this drug. It is therefore considered that SM-4300 is of use for the treatment of intractable bacterial infections when used with antibiotics.

[Preclinical and clinical studies of clindamycin-2-phosphate (author's transl)].

Preclinical and clinical studies of clindamycin-2-phosphate developed as an infectable were conducted, and the following results were obtained: 1) Clindamycin-2-phosphate administered by the intravenous drip in a dose of 600 mg over one hour showed a peak blood clindamycin level of 10.5 mcg/ml at the end of administration. Though the blood level then decreased rapidly, it stayed at 0.7 mcg/ml at 8 hours later. 2) The blood level of clindamycin following intramuscular injection of 300 mg of clindamycin-2-phosphate reached a peak of 3.3 mcg/ml at one hour later. The blood level of 6 hours after injection was 1.0 mcg/ml. 3) Clindamycin-2-phosphate 300 mg was given intramuscularly 2 to 4 times daily for 5 approximately 14 days in 4 cases of pneumonia. The drug proved effective in two cases of pneumonia due to Mycoplasma; fairly effective in another case of mixed infection caused by pneumococci, Hemophilus and N. meningitidis; and ineffective in the fourth case of infection due to Hemophilus parainfluenzae. 4) No such adverse reactions as hepatic disorder, renal disorder and colitis were noted following administration of clindamycin-2-phosphate.