The role of endogenous proteases in the tenderisation of fast glycolysing muscle.

The activities of lysosomal cathepsins and the calpain-calpastatin system were measured to determine their involvement in the more rapid tenderisation of fast glycolysing muscle. The rate of pH fall of M. longissimus dorsi (LD) of Hereford cross Friesian heifers (n = 52, Experiment 1; n = 36, Experiment 2) was measured.

Determination of 3-methylhistidine by capillary electrophoresis.

The post-translational methylation of histidine to form 3-methylhistidine (3MH) is a modification principally found in contractile proteins, and thus, the level of free 3MH has been used to monitor muscle protein turnover. This work describes procedures for the capillary electrophoretic separation and determination of the phenylthiohydantoin (PTH) derivative of 3MH using uncoated fused-silica capillaries. The procedure described here utilized UV detection and resulted in a linear standard curve in the range of 2-15 pmole, which is more sensitive than previously reported HPLC methods using fluorescent detection.

Ultrastructural observations on fibril profiles in normal and degenerative human articular cartilage.

Ultrastructural changes in collagen fibril morphology in human osteoarthritis have not been critically analyzed. In this study, fibril profiles in healthy and fibrillated articular cartilage samples obtained from specimens resected during prosthetic arthroplasty were examined by transmission electron microscopy. Collagen fibrils were deposited parallel to the articular surface in the tangential zone, but were aligned radially to the surface in the deeper layers.

The chondrogenic potential of carbon fiber and carbon fiber periosteum implants: an ultrastructural study in the rabbit.

The articular tissue generated on carbon fiber rods in rabbit knee joints after 75 days of intermittent active motion was compared with tissue generated on carbon fiber rods whose articular surfaces were covered with a free reversed periosteal graft. Both methods were effective in generating articular tissue; however, tissue with ultrastructural characteristics similar to those of hyaline cartilage was noted more frequently on the composite implants. If such composite implants were clinically effective then they might be useful in treating symptomatic osteochondral defects.

A survey to assess the ultrastructural preservation of fixed biological samples after air-drying from tetramethylsilane.

A scanning electron microscope (SEM) survey assessed the quality of ultrastructural preservation of a wide range of tissues from the laboratory rat and from a limited number of botanical and fly-larval samples, air-dried from tetramethylsilane (TMS) after chemical fixation and dehydration. Comparisons were made with critical point drying (CPD) and air-drying from acetone. CPD produced good results in all cases.

Quantitative and morphological observations on the ultrastructure of articular tissue generated from free periosteal grafts.

This study investigates the ultrastructure of articular tissue generated on osteochondral defects in skeletally immature rabbits from free reversed periosteal allografts after 50 and 100 days of post-operative intermittent active motion. Tissue samples prepared for transmission electron microscopy were compared with normal cartilage and periosteum in terms of cell morphology and the pattern of intercellular collagen deposition. Well-differentiated tissue demonstrated many ultrastructural features of normal articular cartilage while poorly differentiated samples contained cells and intercellular collagen profiles which were somewhat similar to those observed in periosteum.

An evaluation of the usefulness of air-drying biological samples from tetramethylsilane in preparation for scanning electron microscopy.

A survey was done, using a limited number of animal, plant and insect samples, to evaluate the quality of structural preservation obtained when chemically fixed tissue is air-dried from tetramethylsilane (TMS). Comparisons were made with critical point drying (CPD) and air-drying from acetone (Controls). CPD samples showed good structural preservation in all cases.

Investigation of the possible effect of the Chernobyl accident on Irish mortality rates.

RADIOACTIVE fallout from the Chernobyl accident reached Ireland in May 1986 and caused serious concern with regard to its possible effects on health. Reports of a large scale American study claim an almost immediate effect of Chernobyl fallout in terms of increased mortality rates. A study of Irish mortality rates reported a substantial increase in numbers of deaths during the three months immediately post-Chernobyl.

A Ca2+-activated protease possibly involved in myofibrillar protein turnover. Subcellular localization of the protease in porcine skeletal muscle.

A study was done to determine whether the Ca2+-activated muscle protease (CAF) that removes Z disks from myofibrils in the presence of Ca2+ is located in a sedimentable subcellular organelle. Porcine skeletal muscle cells were diced finely with a scalpel and were suspended in 0.25 M sucrose, 4 mM EDTA with a VIRTIS homogenizer.

A Ca2+-activated protease possibly involved in myofibrillar protein turnover. Partial characterization of the purified enzyme.

The purified Ca2+-activated protease (CAF) isolated from porcine skeletal muscle and capable of removing Z-disks from intact myofibrils is optimally active on either myofibril or casein substrates at pH 7.5 and in the presence of 1 mM Ca2+ and at least 2 mM 2-mercaptoethanol. No CAF activity is detected when 1 mM Mg2+, Mn2+, Ba2+, Co2+, Ni2+, and Fe2+ are added singly.

A Ca2+-activated protease possibly involved in myofibrillar protein turnover. Purification from porcine muscle.

Ca2+-activated Z-disk-removing activity in the P0-40 crude muscle extracts described by Busch et al. (Busch, W. A.