Tensile properties of the human acetabular labrum-the first report

The tensile properties of the human acetabular labrum were investigated using a uniaxial tension testing apparatus. The superior quadrant of the acetabular labrum was harvested from patients who underwent hip surgery. The obtained labra were sliced and shaped into rectangles for measuring uniaxial tension. We hypothesized that several characteristics such as gender, age, degeneration due to primary ailment, and the severity of the acetabular dysplasia would influence the tensile properties of the labrum. Antero-posterior radiographs of the pelvis have been used to evaluate the severity of the acetabular dysplasia and to diagnose the developmental dysplasia of the hip joint (DDH) clinically. Thus, we investigated the correlation between each of two representative radiological measurements-the CE angle and the Sharp angle-and tensile properties to assess the influence of the severity of the acetabular dysplasia. The tensile stress-strain curves for the labrum assumed a sigmoid shape. The mean tensile stress at failure for all specimens was 8.8+/-4.1 MPa. The mean strain at failure for all specimens was 48.5+/-10.4%. The mean tensile modulus was 66.4+/-42.2 MPa. Mean tensile stress at failure for specimens from males was greater than that of specimens from females. A significant difference was found in the maximum stress at failure among the three diagnosis-based groups: the other group withstood the highest stress before failure, whereas the osteoarthritis (OA) group withstood the lowest. No significant correlations with age or radiological characteristics were found for tensile stress, strain at failure, or tensile modulus. Our results suggest that labra obtained from male patients have stronger tensile stress than those from female patients, and that degenerative changes may influence the properties of the acetabular labrum.     

Visual hallucinations on eye closure after orthopedic surgery under general anesthesia

A 61-year-old woman suffering from rheumatoid arthritis without a contributory neurological, mental, or psychological history experienced visual hallucinations solely on eye closure after total hip arthroplasty under general anesthesia combined with epidural anesthesia. The visual hallucinations first appeared when she arose from sleep early on postoperative day 1, approximately 12 h after the end of surgery. Only on closing her eyes, she had a clear view of colored clothes, lace curtains, handbags, hats, and sofas, all of which were vivid, realistic, complex, of natural size, and in normal perspective without distortion and appeared independently and randomly in succession. The hallucinations disappeared when she opened her eyes even in the dark. The visual hallucinations gradually decreased as the days elapsed and they had entirely subsided on postoperative day 4. The level and content of her consciousness seemed entirely normal throughout her hospital course. Although postoperative visual hallucinations are not uncommon, they do not always show the closed-eye variation. The causes and underlying mechanisms of this type of visual hallucination remain to be elucidated.     

6‐Formylpterin protects retinal neurons from transient ischemia–reperfusion injury in rats: A morphological and immunohistochemical study

Neuroprotective effects of 6‐formylpterin (6FP) on transient retinal ischemia–reperfusion injury were evaluated in rats by means of counting the number of retinal ganglion cells, measuring the thicknesses of the inner plexiform and inner nuclear layers, and by immunohistochemical detection of apoptotic cells in the retina. Sixty‐one Sprague–Dawley rats (12 weeks, male, 295–330 g) were subjected to transient retinal ischemia–reperfusion by elevated intra‐ocular pressure (80 mmHg for 60 min). Intraperitoneal injection of 6FP (3.8 mg/kg) was performed before or after ischemia. The retina was histologically better preserved in rats with 6FP treatment than without 6FP treatment. 6FP showed more strong neuroprotective effects when it was administered before ischemia. The number of single‐stranded DNA‐positive cells in the retina also decreased remarkably in rats with 6FP treatment, especially when administered before ischemia. These results suggest that 6FP protects retinal neurons from transient ischemia–reperfusion injury, at least in part by inhibiting apoptotic cell death.     

Enhancing effect of thoracotomy and/or laparotomy on the growth of ascitic tumor in rats

To evaluate the effect of operative stress on a tumor growth, thoracotomy and/or laparotomy were performed 48 hours after the intraperitoneal inoculation of Sato lung cancer cells in Donryu rats. The survival time and the spread of the tumor were examined. Thoracotomy and laparothoracotomy reduced significantly the survival time of the inoculated rats as compared with the control but no significant difference was observed between the two test groups subjected to operative stress. No difference was observed in the spread of the tumor between the test groups and the control. These results indicated that the operative stress increased only the number of metastatic foci and did not change the characteristics of the tumor cells. Supported in part by Grants-in-Aid from the Ministry of Education, Science and Culture and the Ministry of Health and Welfare.     

Articular cartilage depicted at optimized angular position of Laue angular analyzer by X-ray dark-field imaging.

Using 36.0 keV X-ray from synchrotron radiation, we examined the optimized angular position of Laue analyzer for depicting articular cartilage of an intact human finger by X-ray dark-field imaging. The surface of articular cartilage was depicted clearly by adopting the offset angle of 0.04 arcsec to lower angular side to the analyzer whilst the contour of articular cartilage was delineated clearly at the other angular positions of the analyzer within the width of the rocking curve.     

A Novel Monoclonal Antibody against Squamous Cell Carcinoma

The monoclonal antibody, INS-2, was raised against rat fibroblasts transformed by open reading frames E6 and E7 of human papillomavirus (HPV) DNA. In immunoperoxidase testing of frozen sections, the INS-2 antibody was reactive with all squamous cell carcinomas of the uterine cervix and esophagus tested. In contrast, no antibody binding was detected with adenocarcinomas of various origins. Similarly, normal tissues, lymphoid cells and erythrocytes from multiple donors were negative, except that binding localized at basal cells in normal squamous epithelium was observed. Interestingly, strong staining was observed in dysplastic cells of cervical intraepithelial neoplasia and at the growing edge of squamous cell carcinomas. The antigen for the INS-2 antibody is a non-sialyl glycoprotein with Mw. 40,000 and appears to be a squamous cell-specific cell differentiation marker, although it is not related to HPV-DNA-derived protein.     

Release of the lymphokine osteoclast activating factor requires cyclic AMP accumulation

Summary The bone resorbing lymphokine osteoclast activating factor (OAF) is released by lymphocytes activated by phytohemagglutinin (PHA). In this study we have found that release of OAF by activated lymphocytes is dependent on cyclic AMP (cAMP). OAF release is preceded by cAMP accumulation in the lymphocytes, and when cAMP accumulation is impaired by treatment of activated leukocytes with indomethacin, OAF is not released. OAF release in these cultures is restored by the addition of agents that mimic or increase lymphocyte cAMP content by different mechanisms. When activated purified lymphocytes that do not release OAF by themselves were cultured with these agents, OAF appeared in the culture media. These results suggest that cyclic AMP accumulation in lymphocytes is required for OAF to be released after activation.