Role of caldesmon in the Ca2+ regulation of smooth muscle thin filaments: evidence for a cooperative switching mechanism.

Smooth muscle thin filaments are made up of actin, tropomyosin, caldesmon, and a Ca(2+)-binding protein and their interaction with myosin is Ca(2+)-regulated. We suggested that Ca(2+) regulation by caldesmon and Ca(2+)-calmodulin is achieved by controlling the state of thin filament through a cooperative-allosteric mechanism homologous to troponin-tropomyosin in striated muscles. In the present work, we have tested this hypothesis.

Cooperative inhibition of actin filaments in the absence of tropomyosin.

We measured the inhibition of actin activated myosin subfragment-1 MgATPase activity in a solution containing no added KCl (5 mM PIPES.K2 (pH 7.1), 2.

Telepathology for routine light microscopic and frozen section diagnosis.

Telepathology (TP) uses telecommunication linkages to electronically capture, store, retrieve, and transmit images to distant sites. We assessed the feasibility of a dynamic real-time TP system for light microscopic (LM) diagnosis of anatomic pathology specimens, including frozen sections. Six pathologists, in 2 separate periods, read a set of 160 retrospectively retrieved slides (80 of which were frozen sections) by TP and LM.

Persistent Mullerian duct syndrome associated with transverse testicular ectopia.

Persistent Mullerian Duct Syndrome (PMDS) associated with transverse testicular ectopia (TTE) is rare. Ten cases have been reported in the past. Accurate diagnosis with karyotype and histological analysis is crucial.