Von Willebrand factor (VIII R:Ag), fibronectin, and insulin-like growth factors I and II in diabetic retinopathy and nephropathy.

We have measured plasma von Willebrand factor (VWF) as the factor VIII-related antigen, plasma fibronectin, and two of the serum somatomedins, insulin-like growth factor I (IGF I) and IGF II, in 51 diabetic patients and 25 nondiabetic control subjects. VWF was significantly higher in the diabetic group than in the controls (173 +/- 9% SEM versus 101 +/- 9%, P less than 0.001), as has been reported by others.

Tryptic peptide mapping studies on the regulatory subunits of type II protein kinases from cerebral cortex and heart. Evidence for overall structural divergence and differences in the autophosphorylation and cAMP-binding domains.

Regulatory subunits of type II cAMP-dependent protein kinases (RII) (EC 2.7.1.

Cloning of cDNA sequences for murine ATP-citrate lyase. Construction of recombinant plasmids using an immunopurified mRNA template and evidence for the nutritional regulation of ATP-citrate lyase mRNA content in mouse liver.

Mouse liver mRNA that was enriched in sequences coding for ATP-citrate lyase by polysome immunoadsorption was used as a template for cDNA synthesis. Double-stranded cDNA sequences were inserted into the plasmid pBR322 and cloned in Escherichia coli RR1. Twenty-seven plasmids containing putative cDNA sequences for ATP-citrate lyase were identified by differential hybridization with single-stranded 32P-cDNAs synthesized from immunopurified mRNA, sucrose gradient-purified ATP-citrate lyase mRNA, and mRNA isolated from the livers of mice that were nutritionally induced or de-induced for ATP-citrate lyase biosynthesis.

Cloning of cDNA sequences for murine malic enzyme and the identification of aberrantly large malic enzyme mRNA in MOD-1 null mice.

Polysomes containing cytosolic malic enzyme mRNA and malic enzyme nascent chains were complexed with specific antibodies and purified by chromatography on protein A-Sepharose. When poly(A+) mRNA derived from the immunoselected polysomes was translated in vitro, full length malic enzyme (subunit Mr = 58,000) accounted for a significant fraction (approximately 20%) of the polypeptides synthesized. Double-stranded cDNA, synthesized using partially purified malic enzyme mRNA as a template, was inserted into pBR 322 and cloned.

Static vs dynamic loads as an influence on bone remodelling.

Remodelling activity in the avian ulna was assessed under conditions of disuse alone, disuse with a superimposed continuous compressive load, and disuse interrupted by a short daily period of intermittent loading. The ulnar preparation consisted of the 110mm section of the bone shaft between two submetaphyseal osteotomies. Each end of the preparation was transfixed by a stainless steel pin and the shaft either protected from normal functional loading with the pins joined by external fixators, loaded continuously in compression by joining the pins with springs, or loaded intermittently in compression for a single 100s period per day by engaging the pins in an Instron machine.

Skeletal strain and the functional significance of bone architecture.

Regulation of the magnitude and distribution of skeletal strain is achieved in limb bones both "internally" by alterations to bone morphology, and "externally" by coordination of muscle activity and modifications in the animal's behavior. Though not actually minimizing functional strain, these mechanisms conspire to produce a restricted strain environment, which allows an economical and optimized structure, and, in a variety of species over a wide range of activities, the architectural and behavioral modifications have resulted in remarkably similar peak functional strain magnitudes. This confined range of functional strains reflects a universal mechanism and objective of structural adaptation in bone.

Activation of cyclic AMP-dependent protein kinase isoenzymes: studies using specific antisera.

A novel method for rapidly determining the amount and degree of association-dissociation of the Type I and Type II cAMP-dependent protein kinases has been developed and validated. Antibodies directed against the regulatory subunits of Type I and Type II cAMP-dependent protein kinases were used. The antibodies formed complexes with holoenzymes and regulatory subunits which were precipitated by goat anti-rabbit IgG (immunoglobulin G).

Ultrastructural immunolocalization of apolipoprotein B within human jejunal absorptive cells.

Apolipoprotein B (apoB) was localized by electron microscopy within absorptive cells of human jejunal biopsy specimens taken fasting and after micellar fat infusion. Nakane's double antibody immunoperoxidase technique was used to label apoB near open cut surfaces of 60-Micrometers fixed tissue slices sectioned by a Ralph knife in a Vibratome. In fasting tissue, apoB label was found within structurally intact peri-mitochondrial rough endoplasmic reticulum (RER) and within Golgi cisternae of absorptive cells covering the tips of jejunal villi.

Comparison of stem-cell recovery in autoimmune and normal strains.

The capacity of NZB stem cells to proliferate in vivo was evaluated in two systems which required repopulation of peripheral organs. In both types of depletion systems, stem-cell repopulation after cyclophosphamide treatment or adoptive transfer repopulation in lethally irradiated hosts, it was found that NZB stem cells were hyperproliferating. The increase in proliferating cells was most pronounced in the spleens of NZB mice treated with high-dose cyclophosphamide and in lethally irradiated F1 mice reconstituted with NZB T-cell-depleted bone marrow.

High-performance gel-permeation chromatography of polypeptides in a volatile solvent: rapid resolution and molecular weight estimations of proteins and peptides on a column of TSK-G3000-PW.

A gel-permeation column of TSK-G3000-PW that was equilibrated and developed with 36 or 45% acetonitrile in 0.1% trifluoroacetic acid fractionated mixtures of peptides with high resolving power. In addition, the elution volumes of 11 standard peptides and proteins were linearly related to the logarithms of their molecular weights in the acetonitrile-trifluoroacetic acid solvent at both low and high flow rates.

Regulation of cAMP-dependent protein kinase subunit levels in Friend erythroleukemic cells. Effects of differentiation and treatment with 8-Br-cAMP and methylisobutyl xanthine.

Friend erythroleukemic cells contain both type I and type II cAMP-dependent protein kinases. The amounts of type I and type II regulatory subunits (R I and R II) were established by a combination of the equilibrium binding of cyclic [3H]AMP and specific immunoprecipitation. In control cells the total specific cAMP-binding activity was 9.

Latent insulin receptors and possible receptor precursors in 3T3-L1 adipocytes.

Cell surface and cryptic insulin receptors were solubilized from the particulate fraction of murine 3T3-L1 adipocytes with buffer containing 1% Triton X-100. Solubilized receptors were affinity crosslinked with 125I-labeled insulin and disuccinimidyl suberate and characterized by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and autoradiography after specific immunoprecipitation. Two insulin-binding polypeptides were identified: the more abundant protein had a Mr of 130,000, corresponding to the size of the hormone-binding subunit of insulin receptors on the surface of target cells; the second polypeptide exhibited a Mr of 200,000 and appears to be a component of the latent pool because it was unaffected when 3T3-L1 adipocytes were exposed to trypsin under conditions that result in a 95% reduction in cell surface insulin-binding activity and the loss of the Mr 130,000 polypeptide in crosslinking experiments.

Limb mechanics as a function of speed and gait: a study of functional strains in the radius and tibia of horse and dog.

Rosette strain gauges were attached to the midshaft of the radius and tibia of two horses and two dogs, which ran on a treadmill through their entire range of speed and gait. The relative magnitudes of the principal strains on the opposite cortices of each bone remained constant through the stance phase of the stride, and their orientation varied by a maximum of only 14 degrees through the entire speed range. The maximum strain rate increased linearly with speed, but the peak strain magnitude was also dependent upon the gait used, increasing incrementally by up to 59% at the transition from walk to trot, and dropping by 42% from a trot to a canter.

Clinical experience with a prototype real-time dedicated breast scanner.

The evaluation of 1,003 sonomammographic examinations on a predominantly symptomatic population using a prototype real-time dedicated breast scanner is presented. Interpretations were initially made by one of four experienced radiologists without knowledge of clinical data (i.e.

Insulin activates a tyrosine-specific protein kinase in extracts of 3T3-L1 adipocytes and human placenta.

Insulin activates a tyrosine-specific cAMP-independent protein kinase when added directly to detergent extracts of differentiated 3T3-L1 adipocytes and humal placental membranes. The kinase is also activated by antibody to the insulin receptor and, to a lesser extent, by proinsulin. It catalyzes the phosphorylation of the 92,000-dalton component of the insulin receptor, histone, and casein; in each case, tyrosine is the principal amino acid modified.

Changes in the bone-cement interface after total hip replacement. An in vivo animal study.

Unlabelled: In order to study the temporal sequence of radiographic, histological, mechanical, bacteriological, and chemical changes around the femoral component following total hip replacement, a model was created by implanting plastic-on-metal total hip replacements in sheep and walking the animals on a concrete surface beginning six weeks postoperatively. This model demonstrated a decreased torsional rigidity between the prosthesis and the femoral cortex in all sheep. Failure of bonding occurred at the bone-cement interface and appears from our results to be most probably due to alterations in the functional stress of the proximal end of the femur following insertion of the femoral component rather than exothermic polymerization, toxicity of free monomer residue, or infection.

Dexamethasone regulates the beta-adrenergic receptor subtype expressed by 3T3 L1 preadipocytes and adipocytes.

The subtype of the beta-adrenergic receptor expressed in 3T3-L1 preadipocytes and adipocytes differentiated with dexamethasone and methylisobutylxanthine was determined by comparing the affinity of the receptors for epinephrine, norepinephrine, and beta-1 and beta-2 selective antagonist, 8-fold more avidly than adipocyte receptors. In contrast, adipocyte beta-receptors had a 10-fold higher affinity for epinephrine than for norepinephrine and complexed the beta-2 selective agonist zinterol with a 20-fold higher affinity than preadipocyte receptors. Hofstee plots and computer analyses of the binding data revealed that the populations of beta-1 receptors in preadipocytes and beta-2 receptors in adipocytes were nearly homogeneous.

Pulmonary function in firefighters: a six-year follow-up in the Boston Fire Department.

Tests of ventilatory capacity, objective cough, and standardized respiratory questionnaires were used in a prospective study to measure the effect of firefighting on pulmonary function in a cohort of 951 white Boston firefighters between 1970-1976. During the six years of follow-up, the mean annual decrements in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were 36 and 29 ml per year, respectively. At the end of the study in 1976, the mean FEV1 for this group was 98.

Genetic control of insulin receptors.

Insulin-binding activity was measured in hepatocyte suspensions and liver membrane preparations from newborn mice homozygous for a perinatal-lethal deletion at and around the albino locus in chromosome 7. Cell suspensions and membrane preparations from the mutant mice exhibited only 20-25% of the specific hormone-binding activity observed in comparable preparations from their homozygous normal and heterozygous littermates. The decrease in insulin-binding activity appears to be attributable to a decrease in the number of insulin receptor sites per cell rather than to a change in receptor affinity.