Effects of TGFbeta on bone ingrowth in the presence of polyethylene particles

We implanted bone harvest chambers (BHCs) bilaterally in ten mature male New Zealand white rabbits. Polyethylene particles (0.3+/-0.1 microm in diameter, 6.4 x 10(12) particles/ml) were implanted for two, four or six weeks bilaterally in the BHCs, with subsequent removal of the ingrown tissue after each treatment. In addition to the particles, one side also received 1.5 microg of recombinant transforming growth factor beta1 (TGFbeta1). At two weeks, the bone area as a percentage of total area was less in chambers containing TGFbeta compared with those with particles alone (7.8+/-1.3% v 16.9+/-2.7% respectively; 95% confidence interval (CI) for difference -14.0 to -4.30; p = 0.002). At four weeks, the percentage area of bone was greater in chambers containing TGFbeta compared with those with particles alone (31.2+/-3.4% v 22.5+/-2.0% respectively; 95% CI for difference 1.0 to 16.4; p = 0.03). There were no statistical differences at six weeks, despite a higher mean value with TGFbeta treatment (38.2+/-3.9% v 28.8 +/-3.5%; 95% CI for difference -4.6 to 23.3; p = 0.16). The number of vitronectin-receptor-positive cells (osteoclast-like cells) was greater in the treatment group with TGFbeta compared with that with particles alone; most of these positive cells were located in the interstitium, rather than adjacent to bone. TGFbeta1 is a pleotropic growth factor which can modulate cellular events in the musculoskeletal system in a time- and concentration-dependent manner. Our data suggest that there is an early window at between two and six weeks, in which TGFbeta may favourably affect bone ingrowth in the BHC model. Exogenous growth factors such as TGFbeta may be a useful adjunct in obtaining osseointegration and bone ingrowth, especially in revisions when there is compromised bone stock and residual particulate debris.     

Dislodgement of Intracoronary Thrombus During Angiography in a Patient with Unstable Angina Pectoris

A patient with unstable angina pectoris in whom thrombus release from intracoronary lesion was seen during angiography is described. The event resulted in improvement of vessel patency and resolution of ischemic symptoms. To our knowledge, only two similar cases have been reported in English literature since 1966.     

Cowden syndrome and Lhermitte-Duclos disease.

BACKGROUND. Cowden syndrome (CS) is a rare but underdiagnosed autosomal dominant condition also known as "multiple hamartoma-neoplasia syndrome." Patients have multiple tricholemmomas (a type of benign skin appendage tumor) and oral papillomatosis and cutaneous keratoses. They often have goiter, gastrointestinal polyps, and hamartomatous soft tissue lesions. Breast cancer affects approximately one third of women with CS. Lhermitte-Duclos disease (LDD) is a peculiar proliferation of abnormal neuronal elements of the cerebellum that has features of a hamartoma and of a neoplasm. METHODS. The authors described two patients who have both CS and LDD. Also reviewed were 50 of approximately 62 previously described cases of LDD (identified through literature searches) in an effort to find patients with LDD who had other associated lesions. RESULTS. Only one other patient in whom both LDD and CS were recognized has been reported. In addition, a number of patients with LDD who had other neoplasms and/or thyroid lesions have been described. CONCLUSIONS. Given the rarity of these two entities, we believe that their association is not fortuitous. LDD fits into the concept of CS as a hamartoma-neoplasia syndrome. In addition, a number of patients with LDD who had other neoplasms or thyroid lesions have been reported, raising the possibility that CS and LDD are more closely linked than is generally appreciated. We suspect that there are more patients with LDD who have unrecognized CS. Patients with either of the two diseases should be examined and followed up for evidence of the other.     

Intermittent micromotion inhibits bone ingrowth. Titanium implants in rabbits.

We studied the effects of micromotion on bone ingrowth into a 1-mm canal through a titanium chamber implanted in the proximal tibia of rabbits. The implant surface became "osseointegrated," but an interior core was movable, allowing the central portion of the canal to be moved in relation to the ends. Thus, the ingrowing bone in the canal had to pass an area of ad latus motion. When implanted in rabbit tibiae, the canal became filled with ingrown cancellous bone. Bone ingrowth was inhibited by 20 cycles of 0.5-mm movement applied during a 30-second period once daily. With this regimen, the canal was usually filled with vascularized fibrous tissue and significantly less bone. The micromotion chamber may enable detailed studies of the effects of different motion variables on ingrowth of bone.     

Sexual addiction: designation and treatment.

While there is general agreement that the pattern of behavior described as "sexual compulsivity" or "sexual dependency" or "sexual addiction" does exist, considerable controversy surrounds the issue of how this syndrome should be designated. The principle candidates--compulsivity, dependency, and addiction--are examined, and addiction is found to be the most suitable term. Addiction is then clearly defined, and diagnostic criteria for addictive disorder are specified. After the definition of and diagnostic criteria for sexual addiction are presented, arguments against the concept of sexual addiction are reviewed and answered. Implications of this concept for treatment are then explored.     

The immobilization response in rhesus monkey: a behavioral and electroencephalographic study.

Rhesus monkeys maintained in individual cages are rarely inactive when observed by humans unfamiliar to them. It has been observed that these animals display a greatly reduced behavioral repertoire after they are transferred to primate chairs. The present study used systemic behavioral observations to document those changes and to examine additional changes produced by arm restraint. Chair restraint was associated with a reduction in activity which was intensified when animals were further immobilized by arm restraint. This immobilization produced a reduction of tone in all limbs, a reduction of spontaneous behavior, and the appearance of eye closure. Electroencephalographic (EEG) correlates of the behavioral changes were examined also, using quantitative data generated through power spectral analysis of sensorimotor cortical EEG signals. Immobilization was accompanied by a significant increase in spectral density at 12 to 15 Hz which was most marked at mid and far lateral rholandic recording sites. No other significant changes were seen in the frequency bands studied. When the immobilized animal was alerted with novel stimuli, lower frequencies were attenuated but 12- to 15-Hz activity remained enhanced. These findings indicate that a unique immobilization response is elicited by restraint in the rhesus monkey which is associated with discrete changes in both behavior and accompanying EEG patterns.