t6A and ms2t6A Modified Nucleosides in Serum and Urine as Strong Candidate Biomarkers of COVID-19 Infection and Severity

SARS-CoV-2 infection alters cellular RNA content. Cellular RNAs are chemically modified and eventually degraded, depositing modified nucleosides into extracellular fluids such as serum and urine. Here we searched for COVID-19-specific changes in modified nucleoside levels contained in serum and urine of 308 COVID-19 patients using liquid chromatography-mass spectrometry (LC-MS). We found that two modified nucleosides, N⁶-threonylcarbamoyladenosine (t⁶A) and 2-methylthio-N⁶-threonylcarbamoyladenosine (ms²t⁶A), were elevated in serum and urine of COVID-19 patients. Moreover, these levels were associated with symptom severity and decreased upon recovery from COVID-19. In addition, the elevation of similarly modified nucleosides was observed regardless of COVID-19 variants. These findings illuminate specific modified RNA nucleosides in the extracellular fluids as biomarkers for COVID-19 infection and severity.

Experimental studies on half-joint transplantation. Antigenicity of fresh allografted articular cartilage and changes in the articular cartilage

This study was undertaken to examine the fate of articular cartilage in isogenic half-joint grafts implanted after storage by two-stage freezing. The antigenicity was evaluated quantitatively with regard to humoral and cellular immunological responses: none was seen in allogenic cartilage grafts. In the half-joint transplantations, the antigenicity of the cartilage need not be considered; only the antigenicity of cortical and cancellous bone must be reduced. Histologically, half-joint grafts stored at -196 degrees C were superior to fresh allografts. Two-stage freezing, therefore, appears to be useful for the storage of articular cartilage.

Experiments on antigenicity and osteogenicity in allotransplanted cancellous bone

This experimental study was undertaken in mice to investigate the procedures for storage of allogenic cancellous bone. Cancellous grafts were were stored at -80 degrees C, -196 degrees C or freeze dried. Grafts were implanted into a defect in the recipient's femur and after one week the cellular kinetic activity was analysed by autoradiography. For immunological study, the grafts were implanted into the recipient's muscle, and 2 weeks later the sensitising properties were examined by killer T-cell toxicity and the complement dependent cytotoxicity test. The capacity for osteogenesis of grafts frozen at -196 degrees C was similar to or higher than those freeze dried, but it was low when storage was at -80 degrees C. Immunogenicity was not affected by these three methods of storage and was very similar to that of fresh autografts. Antigenicity of allografts can be decreased by the freezing procedure. We suggest that the greater osteogenic potency after freezing at 196 degrees C is related to the lesser degree of degeneration of the bone matrix.

[A preliminary study on the morphological changes of the microvasculature following the peripheral nerve autografting]

The microvasculature of peripheral nerve following autografting was studied by scanning electron microscopy. The newly-formed capillaries was also examined by transmission electron microscopy. Capillaries of a fascicle were divided into an extrafascicular vascular plexus and an intrafascicular capillary bed; the former capillaries formed networks, while the latter capillaries ran longitudinally and formed slightly spiral curve. Normal intrafascicular capillaries had tight junctions, a continuous basement membrane and pericytes. On the suture line, capillaries of the graft and those of the host were connected by newly developed sinusoidal capillaries, which were formed at the extrafacicular region earlier than at the intrafascicular region. Newly developed sinusoidal capillaries were transformed into glomerulus-like capillaries and formed fine networks. These networks exhibited a normal capillary architecture after reconstruction. The endothelium of newly-formed capillaries showed a discontinuous basement membrane at the early stage of regeneration. An intrafascicular capillary bed was present in the middle part of the graft.

Concentration of interleukin-1 beta in serum and synovial fluid in patients with rheumatoid arthritis and those with osteoarthritis

The concentration of interleukin-1 beta (IL-1 beta) in serum and synovial fluid of the knee of patients with rheumatoid arthritis (RA) and those with osteoarthritis (OA) was examined using a recently developed radioimmunoassay method. The serum concentration of IL-1 beta was below the detection limit of 0.25 ng/ml in all RA and OA patients. The IL-1 beta concentration in the synovial fluid was higher in RA patients than in OA patients. In RA patients, a significant correlation was demonstrated between the synovial fluid IL-1 beta concentration and the erythrocyte sedimentation rate, C-reactive protein level, synovial fluid white blood cell count and Lansbury index. The synovial fluid IL-1 beta concentration decreased with the reduction of the rheumatoid activity by the medication, but tended to increase or remain high when inflammatory activity of RA could not be adequately controlled. The IL-1 beta concentration, easily determined, shows promise as a new quantitative indicator of rheumatoid activity.

Evaluation of arthrography and arthroscopy for lesions of the posteromedial corner of the knee

Injuries of the posteromedial corner of the knee joint were evaluated using the results of clinical, arthrographic, and arthroscopic examinations in 137 surgically treated patients (137 knees) with injuries of the ACL (acute in 61, chronic in 76). The accuracy of each diagnosis was confirmed by determining the site of the injury during the arthrotomy. A tear of the posteromedial corner of the medial meniscus was present in 40 patients, and an accurate diagnosis was made in 29 patients by clinical examination, in all 40 patients by arthrography, and in 38 patients by arthroscopy. Injury of the posterior oblique ligament was noted in 37 patients, and an accurate diagnosis was made in 15 patients by clinical examination, in 35 patients by arthrography, and in 8 patients by arthroscopy. Lesions of the posterior oblique ligament which were not detected in the arthroscopic examination alone were either rupture at the attachment to the femur or longitudinal tears in the meniscofemoral or meniscotibial portion. The results revealed that arthrography is an important means of evaluation in the diagnosis of injuries of the posteromedial corner of the knee joint.

Immunohistochemical localization of interleukin 1 in human growth cartilage

Although it has been reported that interleukin 1 (IL-1) stimulate chondrocytes to produce collagenase and proteoglycanase in vitro, IL-1 producing cells and the function of IL-1 have not been demonstrated in osteocartilaginous tissue in vivo. Immunohistochemical studies of human cartilaginous epiphysis and growth cartilage demonstrated that IL-1 was detected in: (1) chondrocytes surrounding cartilage canal, (2) hypertrophic chondrocytes in cartilaginous epiphysis, (3) chondrocytes at the hypertrophic and calcified zones in the growth cartilage of actively growing bone. In contrast, few hypertrophic chondrocytes showed positive reactions to IL-1 in growth plates nearing physiologic closure. Furthermore, IL-1 was detected in chondrocytes cultured from human growth cartilage. These results show that IL-1 is produced by matured chondrocytes of human growth cartilage in vivo. Chondrocyte-derived IL-1 might play a key role in the hypertrophy of chondrocytes, in the vascularization of cartilage and in the formation of bone.

The recovery of growth cartilage after removal of bone bridge between epiphysis and metaphysis

The in vitro proliferation of chondrocytes from the tibial growth plate of rabbits has been examined following bone bridge formation and its resection in vivo. In vitro 3H-thymidine incorporation by growth cartilage with bone bridges was 53.5% of the contralateral normal growth cartilage, whereas it was 95.7%, following removal of the bone bridges performed five days before sacrifice. Relative 3H-thymidine incorporation into the growth cartilage decreased with increasing discrepancy of tibial length caused by persisting bone bridges. These experiments demonstrated that growth cartilage can recover its proliferative potential following removal of a mechanical growth inhibition caused by the formation of a bone bridge.

[The relationship between cell kinetics and histological features of giant cell tumor of the bone]

This study was undertaken to clarify the relationship between the proliferative activity and histological findings of the giant cell tumor (GCT) of bone by means of an epi-illumination cytofluorometer (NIKON SPM-RF1-D). Fresh tissues of GCT were surgically obtained from two cases. In both cases, small pieces of tumor tissues were obtained from several different regions based on the macroscopic characteristics of the cut surface, and processed for single cell preparation using enzymatic method. These isolated cells were smeared and stained with acridine orange, and then analyzed cytofluorometrically to determine simultaneously DNA and RNA contents of the individual cells. The results showed that the proliferative activity of tumor cells was much higher in the regions composed of both many histiocytic stromal cells having polygonal or ovoid shape and many multinucleated giant cells, than either in the regions composed of fibrocytic stromal cells accompanying abundant collagen fibers or in the regions composed of foamy cells.

The transplantation of an autogeneic osteochondral fragment for osteochondritis dissecans of the knee

Osteochondritis dissecans in two adults with a large osteochondral defect on the weight-bearing surface was treated by transplantation of an autogeneic osteochondral fragment. The graft was transplanted from the normal portion of the medial femoral condyle, which in extension was in contact with neither patella nor meniscus. The donor site was repaired with an iliac bone fragment. After curettage of the crater, the osteochondral fragment was transfixed with AO mini-cancellous screw(s). Six months after the operation, the grafted cartilage of one patient looked the same as normal cartilage when macroscopically observed and showed no sign of histologic degeneration. At the follow-up examination, the patients were asymptomatic. One patient had a full range of motion two years and three months later; the other three years later. Roentgenographic examinations revealed slight irregularities at the grafted site. There was no significant change in the patellofemoral joint except the concavity of the donor site.

Rotational alignment of the lower limb in osteoarthritis of the knee

Rotational alignement of the lower limbs in 43 patients with osteoarthritis of the knee was measured by computerized tomography. Eighty-four limbs were classified in three subsets, patello-femoral osteoarthritis (subset P), medial femorotibial osteoarthritis (subset M) and lateral femorotibial osteoarthritis (subset L). The femorotibial angle of subset M was 5 degrees greater than that of subset P on the average. Femoral torsion of subset P was significantly greater than that of subset M. Femoral torsion in osteoarthritis of the knee was correlated with external tibial torsion and external torsion of the leg, which included both external rotation at the knee and external tibial torsion. External torsion of the leg in subset M was less than normal and rotational alignment of subset P was also outside the normal range. Our findings show that the frontal and rotational alignment of the lower limb are aetiological factors in osteoarthritis of the knee.

An investigation of the digital nerves of the thumb

With the use of a stereoscopic microscope, observations were made on the course of the proper digital nerve of the thumb on ten upper limbs in adult cadavers. By observation from the dorsal side after removal of the bone, it was possible to clearly see the ramification of the digital nerve from the subcutaneous tissue to the dermis. Ramification from the palm to the level of the interphalangeal joint was segmental. The digital nerve of the thumb trifurcates from the proximal site of the distal palmar thumb crease into the main, medial, and lateral branches. The main branch is thick and extends from the center of the pulp toward the fingertip. Ramification at the pulp of the thumb is of a radiating rather than segmental type, and its control can be considered as spotty or intermittent. Distribution of pacinian corpuscles is dense in the subcutaneous tissue of the distal palmar thumb crease. These observations are of clinical importance not only for avoidance of injury to the digital nerve in surgical procedures such as the incision and drainage for felon and the trigger thumb release but also for precise repair of the digital nerve in the reconstructive surgery of the thumb.

[DNA cytofluorometric analysis of nerve sheath tumors]

The present study was undertaken to clarify the ploidy patterns of peripheral nerve sheath tumors by determining nuclear DNA content of the individual tumor cells using PI-DNA cytofluorometry (NIKON SPM-RF1-D), and to investigate the relation between the ploidy patterns and histopathological findings. Most of the solitary neurilemmomas and neurofibromas studied were found to be associated with euploid-polyploidization, almost without DNA synthetic cells. It was also shown that the number of polyploid cells increased in accordance with an increase in the frequency of cells having large, atypical nuclei in histological picture, regardless of the natures of cellular arrangements. Malignant schwannomas, however, were composed of many polyploid and aneuploid cells with an increase of DNA synthetic cells, indicating their active cell proliferation. Thus, the ploidy patterns of nerve sheath tumors were remarkably different between benign and malignant ones. Furthermore, a case of multiple schwannoma suspected to be a variant of von Recklinghausen's disease, showed euploid-polyploidization with many DNA synthetic cells, indicating a ploidy pattern intermediate between benign and malignant tumors. This tumor thus appears to be a premalignant tumor or in the early stages of malignancy.

[DNA-RNA cytofluorometric analysis of a case of osteosarcoma in relation to histological characteristics]

We applied DNA-RNA cytofluorometry with AO stain to cell kinetic analysis of osteosarcoma in a 12-year-old girl in relation to its histological characteristics. Histological findings obtained for 9 macroscopically different lesions were grouped into 4 main structural characteristics, but their cytofluorometric results were classified into 2 main patterns of DNA-RNA distribution. One showed remarkable polyploidization with many DNA synthetic cells in the invasive lesions, which were composed of pleomorphic cells forming osteoid or occasionally cartilaginous matrix. The other showed marked accumulation of tetraploid cells almost without DNA synthetic cells, being composed of relatively uniform fibroblastic or stellate-like cells in the cartilaginous matrix. These results indicated a close relationship between cell proliferative activity and the tissue environment.

[DNA cytofluorometry of soft tissue tumors]

We carried out DNA cytofluorometry with propidium iodide stain on the 17 cases of soft tissue tumors including giant cell tumor of the tendon sheath, pigmented villonodular synovitis, 2 hemangiomas, 3 lipomas, 5 schwannomas, 3 neurofibromas, liposarcoma and synovial sarcoma. The benign tumors were characterized by regular polyploidization with very few S-phase cells, indicating slow tumor growth. Most of the malignant soft tissue tumors were associated with remarkable polyploidization with an increase in S-phase cells. However, some malignant tumors did not show polyploidization. We concluded, therefore, that an increase in S-phase cells is an important, cytofluorometric criterion for malignancy of soft tissue tumors.

Sports and peripheral nerve injury

Peripheral nerve injury is one of the serious complications of athletic injuries; however, they have rarely been reported. According to the report by Takazawa et al., there were only 28 cases of peripheral nerve injury among 9,550 cases of sports injuries which had been treated in the previous 5 years at the clinic of the Japanese Athletic Association. The authors have encountered 1,167 cases of peripheral nerve injury during the past 18 years. Sixty-six of these cases were related to sports (5.7%). The nerves most frequently involved were: brachial plexus, radial nerve, ulnar, peroneal, and axillary nerves (in their order of frequency). The most common causes of such injuries were mountain climbing, gymnastics, and baseball. More often, peripheral nerve injury seemed to be caused by continuous compression and repeated trauma to the involved nerve. Usually it appeared as an entrapment neuropathy and the symptoms could be improved by conservative treatment. Some of the cases were complicated by fractures and surgical exploration became necessary. Results of treatment produced excellent to good improvement in 87.9% of the cases. With regard to compartment syndrome, the authors stress the importance of early and precise diagnosis and a fasciotomy.

[Quantitative analysis of nuclear DNA of rat chondrocytes during the course of growth and aging--Feulgen-DNA cytofluorometry method]

There have been no reported studies on the Feulgen-DNA cytofluorometry of the cartilage cells. We have attempted to devise a method of cell separation from the epiphyseal and articular cartilages of the rats, and to analyze by cytofluorometry the changes in the ploidy patterns of these chondrocytes during growth and ageing of the animals. Chondrocytes were isolated from the proximal cartilage of tibia by dual enzymatic digestions of the cartilage matrix with papain and collagenase, followed by mechanical cell separation with scissors and a micro-homogenizer, and were smeared onto the object glass with PBS. These procedures were found to be suitable for the Feulgen-DNA cytofluorometry of the chondrocytes from our repeated studies. We also carried out Feulgen-DNA cytofluorometry combined with 3H-thymidine autoradiography to determine cellular DNA content of the DNA synthetic chondrocytes in the epiphyseal cartilage. It has been clarified that during the growth course of the rats, the chondrocytes of the epiphyseal cartilage consist of many mononuclear diploid cells, a few mononuclear tetraploid cells and of some fraction of the cells having intermediate DNA values between the diploid and tetraploid levels. Those cells with intermediate DNA values, after autoradiographic studies, were found to correspond to DNA synthetic cells, indicating cell proliferative activity. It has been shown that during ageing of the rats, most of the chondrocytes from the articular cartilage are mononuclear diploid cells. The distribution of each cellular DNA content at the diploid level as determined by Feulgen-DNA cytofluorometry was shown to become gradually broader.

Evaluation of femoral neck fracture healing in man by serial 99mTc-diphosphonate scintimetry

99mTc-diphosphonate uptake was measured in thirty-four patients with intracapsular fractures of femoral neck and in sixteen patients with trochanteric fractures during their healing process. A peak value in count ratio was recorded in all patients 4 to 6 weeks after fractures. Fifty patients were classified into a normal healing group and a delayed or non-union group. Namely, 99mTc-diphosphonate uptake was significantly higher in the delayed or non-union group than in the normal healing union group 10 weeks after injury. The application of 99mTc-diphosphonate scintimetry seems to make it possible to differentiate objectively the normal healing union from the delayed or non-union.

Effect of human leukocyte interferon on the metastatic lung tumor of osteosarcoma: case reports

Three patients with pulmonary metastases of osteosarcoma underwent treatment with intravenous or intramuscular administration of human leukocyte interferon. In 2 cases, the size of the metastasized tumor mass diminished temporarily six or eight months after interferon treatment, and serum alkaline phosphatase levels decreased to normal. In 1 case, the tumor cell from the pleural exudate 1 could be isolated and cultivated in vitro. When 2,000 IU of interferon was added to the tumor cell culture, marked inhibition of tumor cell growth resulted. In the other case, interferon had no effect on the metastasized lung tumor.

Entrapment neuropathy due to bilateral epitrochleoanconeus muscles: a case report

A case of bilateral entrapment of the ulnar nerves due to accessory epitrochleoanconeus muscles was observed in a young athlete. Hypertrophy of this muscle may be one of the causes of cubital tunnel syndrome.

[External fixation with autopolymerizing acrylic resin]

In November 1970, a new method of skeletal fixation was devised using self-curing acrylic resin. Manipulative reduction of the displaced fracture is made using screws inserted into the bone fragments under an image intensifier. After reduction, the proximal and distal fragments are joined together with the aid of self-curing acrylic resin. Adjacent joints can be exercised immediately after operation and the fixation is so firm that the use of a plaster cast after operation is not necessary. This simple method can be used in osteosynthesis, compression arthrodesis and various types of osteotomy.