Endoscopic anterior cruciate ligament reconstruction using a computer-assisted fluoroscopic navigation system

Background During anterior cruciate ligament (ACL) reconstruction, placement of the reconstructed ligament affects the clinical results. To accomplish accurate and reproducible placement of the tibial bone tunnel, we employed a fluoroscopic navigation system for endoscopic ACL reconstruction. In this study, preciseness of the tibial tunnel placement was evaluated, and the advantages and disadvantages of this navigation system for endoscopic ACL reconstruction are discussed. Methods Altogether, 16 knees of 16 patients who had undergone ACL reconstruction using this system (navi group) were evaluated regarding the positioning of the tibial tunnel against Blumensaat's line using X-p and the route of the graft by magnetic resonance imaging (MRI). Another 16 knees of 16 patients who underwent endoscopic ACL reconstruction without the navigation system were the controls (control group). Results At the 1-year follow-up, maximally extended lateral knee X-p revealed that the anterior edge of the tibial tunnel and Blumensaat's line were almost aligned and that roof impingement was avoided; the T2-weighted MR images showed that the graft was placed close to and parallel to the intercondylar roof in all the knees of the navi group. The ratio of the distance between Blumensaat's line and the anterior edge of the tibial tunnel at the level of the tibial plateau to the anteroposterior width in fully extended true lateral radiographs was 2.7% ± 3.4% in the navi group and 8.4% ± 7.4% in the control group. Conclusions The computer-assisted fluoroscopic navigation system improves accuracy and decreases dispersion of the tibial tunnel placement against Blumensaat's line in single-bundle ACL reconstruction. This innovative device renders the reconstruction procedure more reliable, eliminating the problem of skeletal variation among patients. However, the function of this navigation system for femoral tunnel placement is insufficient at present. Further refinement of the system is necessary, and the method of application requires improvement.     

Activation of protein kinase C and nicotinamide adenine dinucleotide phosphate oxidase in leukocytes of spontaneously hypertensive rats.

The involvement of oxidative stress in polymorphonuclear leukocytes (PMN) in the pathogenesis of hypertension remains to be elucidated. We analyzed the generation of reactive oxygen species (ROS) by the circulating and peritoneally infiltrating PMN from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). Flow cytometric analysis revealed that ROS generation by PMN from SHR was higher than that from WKY before (at 6 weeks of age) and after (at 16 weeks of age) the onset of hypertension. In vivo, ROS generation by PMN from SHR, but not that by PMN from WKY, was significantly suppressed by 10-week treatment with 50 mg/kg/day carvedilol, and this treatment did not affect blood pressure. Western blotting analysis revealed that protein kinase C alpha (PKCalpha), but not PKCbetaI or betaII, was activated more strongly in PMN from SHR than in PMN from WKY. Furthermore, expression of p47phox of nicotinamide adenine dinucleotide phosphate oxidase, but not of p67phox, in PMN from SHR was higher than that in PMN from WKY. These results suggest that ROS generation by PMN is principally enhanced in SHR through activation of PKCalpha and p47phox.     

Adsorption of Human Recombinant Erythropoietin on Dialysis Membranes In Vitro

Abstract: The adsorptive characteristics of 5 dialysis membranes for recombinant human erythropoietin (EPO) were studied in vitro in a closed circuit system. For 120 min, EPO added with bovine serum was significantly adsorbed by polymethylmetacrylate (PMMA) and polyacry–lonitrile (PAN) membranes but not by Cuprophan, ethylene vinyl alcohol (EVAL), or polysulfone (PS) membranes. In addition the EPO adsorptive rate, as well as that of β₂–microglobulin (β₂–MG), was greater with a PMMA membrane than with a PAN membrane. EPO was not detected in the ultrafiltrate at 15 min with 5 membranes. These results indicate that EPO was eliminated by membrane adsorption only with some dialysis membranes.     

Effect of systemic zinc administration on delayed neuronal death in the gerbil hippocampus

The divalent cation zinc has been reported to possess several physiological properties such as blocking apoptotic cell death through an inhibitory effect on Ca²⁺-Mg²⁺ endonuclease activity, or modulating the neurotoxicity via glutamate receptor subtypes. In the present study, we investigated the effect of peripherally injected zinc on delayed neuronal death seen in the hippocampus after transient global ischemia, in order to elucidate a possible beneficial role on zinc in ischemic neuronal cell death. Forty-five adult Mongolian gerbils of both sexes underwent transient bilateral clipping of the common carotid arteries for 3 min. In the pretreated animals, ZnCl₂ (20 mg/kg) was injected subcutaneously once, 1 h before ischemia (superacute group; n=6) or twice at 24 and 48 h before ischemia (subacute group; n=14). Histological survey was carried out 3 days later by in situ DNA fragmentation method and 4 days later by hematoxylin-eosin staining by semiquantatively counting dead neurons in the CA1 sector. Subacute zinc pre-administration significantly reduced the nuclear damage and subsequent neuronal death; however, superacutely pre-administered zinc did not protect hippocampal neurons against ischemia but it did not aggravate the effect of ischemia, either. The present study suggested that transfer of exogenous zinc into the intracellular space is required for neuroprotection, presumably via the anti-endonuclease activity.     

Determination of ion recombination loss by two-voltage method for pulsed radiation beams.

The ion recombination loss is one of the most important correction factors for dosimetry using ionization chamber especially for the measurement of high-intensity pulsed radiation beam. The two-voltage method has been used frequently for the correction of ion recombination loss. Several ways to approximate the method are presented. Comparisons were carried out to check the validity of the approximation. Using four ionization chambers of different types and shapes, measurements were made to obtain the optimal value of the ratio for the two voltages.     

Production of human hematopoietic survival and growth factor by a myeloid leukemia cell line (KPB-M15) and placenta as detected by a monoclonal antibody

Fifty-five hematopoietic cell lines, including 19 T-, 16 B-, 5 pre-B-, 5 non-T non-B-, 1 erythroid, and 9 myeloid-monocytoid cells, were screened for production of human hematopoietic survival and stem cell growth factor (SCGF) by enzyme immunoassay using anti-SCGF monoclonal antibody. The KPB-M15 myeloid cell line constitutionally secreted a considerable quantity of SCGF, while other T- or myeloid-monocytoid cell lines did not secrete SCGF. Other biomaterials investigated were fetal calf, horse, and human serum; granulocyte-macrophage colony-stimulating factor and erythropoietin preparations; human placental conditioned medium; lectin (phytohemagglutinin, concanavalin A, and pokeweed mitogen); and mixed leukocyte reaction-stimulated leukocyte-conditioned medium. SCGF was detected only in human placental conditioned medium. SCGF produced by the KPB-M15 cells was a protein with a molecular weight of 20,000. The molecule, highly purified by immunoadsorbent affinity chromatography, retained SCGF activity in vitro, e.g., erythroid burst-promoting activity and granulocyte-macrophage-colony potentiation. With the availability of purified SCGF, it is now possible to study in detail the mechanisms regulating hematopoietic stem cells.     

Effects of AETT-Induced Neuronal Ceroid Lipofuscinosis on Learning Ability in Rats

Abstract: The behavioral effects of ceroid-lipofuscin accumulation, induced by intraperitoneal administration of acetyl-ethyl-tetramethyl-tetralin (AETT) in Wistar rats for 3 months, were examined in the present studies. A significant increase in neuronal ceroid-lipofuscin was demonstrated neuropathologically as well as morphometrically. Although the AETT-intoxicated rats showed neither alteration of locomotor activity nor shock sensitivity, a significant impairment of learning ability, especially an acquisition trial in passive avoidance tests, was observed. Results of the present studies indicate the possibility that a diffuse lipofuscin accumulation causes a learning impairment in rats. The results also imply the possibility of a significant role of age-related lipofuscin accumulation in the dementing processes of human especially in the elderly.     

Hemorrhagic cystitis after bone marrow transplantation: importance of a thin sectioning technique on urinary sediments for diagnosis.

We used a thin-sectioning technique for the electron microscopic detection of viral particles within the cells of urinary sediments in three recipients who developed hemorrhagic cystitis after allogeneic bone marrow transplantation. Results of viral cultures of urine and electron microscopic (EM) observations on urinary sediments were consistent in only one recipient. In this recipient, EM observations revealed many viral particles within the cells of urinary sediments with diameter of about 80 nm corresponding to adenovirus, of which type 11 was produced in viral cultures. In one of the other two recipients many viral particles with a mean diameter of 41.6 nm corresponding to papovavirus were observed, but viral cultures using conventional cells were negative. Re-cultures using HEK cells produced polyomavirus BK. EM observation was a clue to the correct diagnosis. In the remaining recipient, no viral particles were observed within the cells of urinary sediments, suggesting the hemorrhagic cystitis to be of non-viral origin, despite a positive result of viral culture. These results suggest that a thin-sectioning technique on the cells of urinary sediments is important for the differential diagnosis between a viral-induced and non-viral hemorrhagic cystitis.