Genetic linkage of the tricho-dento-osseous syndrome to chromosome 17q21

Tricho-dento-osseous syndrome (TDO), MIM# 190320, is transmitted as a highly penetrant autosomal dominant trait that is characterized by variable clinical expression. The principal clinical features include kinky/curly hair in infancy, enamel hypoplasia, taurodontism, as well as increased thickness and density of cranial bones. Possible genetic linkage has been reported for TDO with the ABO blood group locus, but the gene defect remains unknown. We have identified four multiplex families (n = 63, 39 affected, 24 unaffected) from North Carolina segregating TDO. We previously have excluded a major locus for TDO in the ABO region for these families. Utilizing a genome-wide search strategy, we obtained conclusive evidence for linkage of the TDO syndrome locus to markers on chromosome 17q21 (D17S791, Z max = 10.54, Theta = 0.00) with no indication of genetic heterogeneity. Multipoint analysis suggests the TDO locus is located in a 7 cM chromosomal segment flanked by D17S932 and D17S941. This finding represents the first step towards isolation and cloning of the TDO gene. Identification of this gene has important implications for understanding normal and abnormal craniofacial development of hair, teeth and bone.      

Preparation of a proteolytic enzyme mixture containing trypsin,elastase, and chymotrypsin for use in tissue disaggregation

Summary We describe a purification method for tissue culture-grade trypsin that yields an enzyme mixture with reproducible activities of trypsin, elastase, and chymotrypsin and eliminates amylase and lipase.     

The activated plasma recalcification time. A Measurement encompassing the activated partial thromboplastin time and platelet function, with improved detection of bleeders.

A study of 300 patients is presented to demonstrate the effectiveness of the activated plasma recalcification time (APRT) as a measure of the intrinsic pathway and platelet function in the detection of bleeders. The activated partial thromboplastin time (APTT) and platelet count were determined in all patients having both normal and abnormal APRT's and the results correlated with overt bleeding tendencies. Abnormality of the APTT is closely paralleled by abnormality of the APRT, independent of the platelet count. When the APTT is normal, an abnormal APRT will characterize clinical bleeders with greater frequency than will the platelet count. The value of the APRT is greatest when done in concert with other standard coagulation measurements, as it both reinforces and expands their diagnostic capability.