Temporomandibular joint: morphology and signal intensity characteristics of the disk at MR imaging

Magnetic resonance (MR) imaging has been used in the temporomandibular joint (TMJ) primarily to define the disk position. This report examines altered morphology and signal intensity characteristics of the TMJ disk as they relate to the severity of internal derangement. Two hundred sixteen joints in 133 patients with a history of such derangement. were imaged with MR. Disk position, signal intensity, morphology, and the presence of osteoarthritis were determined for each joint. The normal disk was not anteriorly displaced and had a normal "bow-tie" shape. A grade 1 disk was anteriorly displaced and had a normal shape; a grade 2 disk was anteriorly displaced and had an abnormal shape. Forty (19%) joints were considered normal; none of these exhibited osteoarthritis. One hundred thirty-nine (64%) joints were grade 1; osteoarthritis was found in 17%. Thirty-seven (17%) were grade 2; osteoarthritis was found in 95%. All forty normal joints had high or intermediate signal intensity in the disk. Osteoarthritic joints had a higher percentage of disks with diminished intensity (P less than .0001). Severe or untreated osteoarthritis is known to be a complication of TMJ internal derangements; hence this grading system seems to correlate with the severity of internal derangement.     

Induction of a stable hapten-specific immunosuppression by a hapten conjugated to poly(N-vinylpyrrolidone) (PVP).

The ability of a hapten coupled to a clinically permissive synthetic polymer (NIP-PVP) to induce suppression was investigated. NIP coupled to the low molecular weight non-immunogenic form of poly(N-vinylpyrrolidone) (PVP) was found to be capable of inducing a hapten-specific longlasting suppression of both primary and secondary responses. The previous use of PVP as a plasma expander in humans makes this polymer a potentially suitable tool for the induction of specific immunosuppression to a variety of clinically important drug and tissue specific epitopes. The possible use of low molecular weight PVP for that purpose will be investigated further, specifically with larger antigenic components.     

Characterization of dystrophin in muscle-biopsy specimens from patients with Duchenne's or Becker's muscular dystrophy

A deficiency of the protein dystrophin has recently been shown to be the probable cause of Duchenne's muscular dystrophy. We sought to determine the relation between the clinical phenotype and the status of dystrophin in muscle-biopsy specimens from 103 patients with various neuromuscular disorders. We found very low levels (less than 3 percent of normal levels) or no dystrophin in the severe Duchenne phenotype (35 of 38 patients), low concentrations of dystrophin in the intermediate (outlier) phenotype (4 of 7), and dystrophin of abnormal molecular weight in the mild Becker phenotype (12 of 18). Normal levels of dystrophin of normal molecular weight were found in nearly all the patients (38 of 40) with 20 other neuromuscular disorders we studied. These data show the clinical consequences of both quantitative alterations (in Duchenne's and intermediate dystrophy) in a single protein. The biochemical assay for dystrophin should prove helpful in delineating myopathies that overlap clinically with Duchenne's and Becker's dystrophies, and it shows promise as an accurate diagnostic tool.     

Minimal progesterone support required for the maintenance of pregnancy in mice

A study of the degree of progesterone support required for the maintenance of various stages of pregnancy was undertaken in mice. Mated females were ovariectomized at various stages of pregnancy and progesterone and oestradiol support provided by s.c. Silastic implants with known release characteristics. In the earliest stages of pregnancy (days 1-5), very low concentrations of progesterone (<25% of normal physiological values) were sufficient to maintain pre-implantation stages and allow implantation. In the immediate post-implantation period (days 5-9), the development of implantation sites and decidualization required considerably higher progesterone support. In mid-pregnancy (days 11-14), progesterone alone could not maintain pregnancy unless present in very high amounts; however, the presence of oestradiol during this period lowered the progesterone requirements to well within the physiological range. This effect of oestradiol started on day 11 but required the level of oestradiol support to be kept within strictly defined limits, with high concentrations inducing abortion. Progesterone alone was able to maintain pregnancy from day 15. These results indicate that the minimal progesterone support required for pregnancy in mice varies considerably at different stages of pregnancy and is at least partly modulated by oestradiol.      

Elastin point mutations cause an obstructive vascular disease, supravalvular aortic stenosis

Supravalvular aortic stenosis (SVAS) is an inherited obstructive vascular disease that affects the aorta, carotid, coronary and pulmonary arteries. Previous molecular genetic data have led to the hypothesis that SVAS results from mutations in the elastin gene, ELN. In these studies, the disease phenotype was linked to gross DNA rearrangements (35 and 85 kb deletions and a translocation) in three SVAS families. However, gross rearrangements of ELN have not been identified in most cases of autosomal dominant SVAS. To define the spectrum of ELN mutations responsible for this disorder, we refined the genomic structure of human ELN and used this information in mutational analyses. ELN point mutations co-segregate with the disease in four familial cases and are associated with SVAS in three sporadic cases. Two of the mutations are nonsense, one is a single base pair deletion and four are splice site mutations. In one sporadic case, the mutation arose de novo. These data demonstrate that point mutations of ELN cause autosomal dominant SVAS.