The in vivo kinematics of the rheumatoid wrist

The objectives of this study were to describe the three-dimensional in vivo kinematic behavior of wrists affected by rheumatoid arthritis, to correlate kinematic parameters and two radiographic indices of carpal disease, and to describe the in vivo kinematic behavior of the Swanson Silastic wrist implant. Fifteen normal wrists, 17 rheumatoid wrists, and 7 wrists with Silastic wrist implants were tested using a three-dimensional sonic digitizing system. The motion of the hand segment relative to the forearm segment, corresponding to the positions exhibited during flexion-extension motion (FEM) and radial-ulnar deviation (RUD), was described using the equivalent screw displacement (ESD) concept. The mean magnitudes of ESD rotation for both FEM and RUD were statistically different (p less than 0.05) among the normal, rheumatoid, and implant groups. The remaining ESD parameters (i.e., mean values for the translation, the direction angles of the ESD axis, and the intercepts of this axis with the planes of motion), the minimum separation between the FEM and RUD axes, and the coordinates of the midpoint of this separation were not statistically different (p greater than 0.05) among the normal, rheumatoid, and implant groups. The two radiographic indices (carpal collapse and carpal translation) did not correlate with the magnitude of rotation or with any other ESD parameter.

Characterization of the primary gene product of rat incisor alpha-phosphophoryn

The nature of the primary gene product for the alpha-phosphophoryn component of rat incisor dentin has been examined by cell-free translation of the total RNA and poly(A+) mRNA from rat maxillary incisors, including pulp cells and odontoblasts. The RNA was extracted by the guanidinium thiocyanate method and translated in a rabbit reticulocyte system. The translated proteins were analyzed by gradient gel electrophoresis, and alpha-phosphophoryn was identified by isolation on an anti-rat alpha-phosphophoryn antibody coupled Sepharose column and dot-blot procedures. The major protein identified as alpha-phosphophoryn had a molecular weight of 153 000 (+/- 5000) and had chromatographic properties similar to those of alpha-phosphophoryn. Since tissue-isolated rat phosphophoryn has a molecular weight of only approximately 90 000 when fully phosphorylated, it appears that the primary gene product is a prepro-alpha-phosphophoryn. Thus, alpha-phosphophoryn in the extracellular space of rat incisor dentin must be the product of one or more posttranslational proteolytic processing steps.

On the propagation of error in air pollution measurements

Four methods for estimating the uncertainties in air pollution measurements are outlined. The approaches are: analytical solution-approximation; application of distribution theory; experimentation; and simulation. The advantages and disadvantages of each method are illustrated using data from High-Volume air samplers, the instrument most commonly used for monitoring ambient concentrations of airborne particles.

Proton magnetic resonance studies on peptide fragments of troponin-C containing single calcium-binding sites

Proton magnetic resonance spectroscopy has been employed to study the solution conformation of three cleavage fragments of troponin-C, each containing a single Ca(II)-binding site and corresponding to different regions in the primary sequence; viz. CB8 (residues 46-77), CB9 (residues 85-134) and TH2 (residues 121-159). Although all three peptides lack a well-defined tertiary fold in the absence of metal ions, several spectral features indicate the presence of local conformational constraints in each apo-peptide. Ca(II) binding led to spectral changes consistent with increased restriction of backbone motility and the adoption of a more compact conformation. Studies using paramagnetic ions as conformational probes support current views concerning the nature of the ligands at the metal binding sites. The nature and kinetics of the structural influence of metal binding suggest that the conformational constraints existing in the CB8 apo-peptide provide an adequate Ca(II)-binding configuration. In contrast, the CB9 and TH2 peptides exhibit spectral changes consistent with an increased local structure in the region of helix E (residues 94-102) in the case of CB9 and helix H (residues 148-159) in the case of TH2. In CB9, conformation changes also appear to be transmitted to a portion of the sequence (residues 87-93) preceding helix E, a putative site of interaction between troponin-C and troponin-I. These data are discussed with reference to the contribution of long-range (interdomain) interactions within troponin-C and the modulation of troponin subunit protein-protein interactions by Ca(II) binding.

Protein-protein interaction sites in the calcium modulated skeletal muscle troponin complex

The sequence domains that contribute to the surfaces of contact between Troponin-C and the other regulatory protein subunits of skeletal muscle troponin are proposed on the basis of data obtained by proton magnetic resonance and other physicochemical studies on the interaction with Troponin-I of both Troponin-C and its peptide fragments. Marked sequence homology in Troponin-C from various species is found for the residues involved in subunit linkage. The role of the recognition sites is discussed.

Proton magnetic resonance studies on proteolytic fragments of troponin-C. Structural homology with the native molecule

Comparison of proton magnetic resonance spectra of a tryptic and a thrombin fragment of troponin-C with that of the native protein has identified the domain of the molecule influenced by Ca2+ binding to the lower affinity regions I and II of troponin-C. The binding of Ca2+ to these sites results in a subtle alteration of the tertiary fold of the N-terminal half of troponin-C involving weakened contacts between several hydrophobic groups. The role and kinetics of the movements within the troponin-C molecule associated with binding at the regulatory sites are discussed.

Manufacture of antithymocyte globulin (ATGAM) for clinical trials

Methods are described for preparing large amounts of horse anti-human thymocyte globulin (ATG, ATGAM; The Upjohn Company) for clinical use. These methods have been used since 1968 to provide material for clinical trials. Characteristics of 40 lots of ATG are summarized.

The influence of thiamin deficiency on the metabolism of the oral contraceptive mestranol [3-methoxy-17-ethynyl-1,3,5(10)-estratrien-17 beta-o1] by female rat liver enzymes

Hepatic microsomes from female rats fed a thiamin deficient diet for three weeks had approximately three times the capacity to metabolize mestranol as microsomes from similar rats fed a diet rich in thiamin. The incremental addition of thiamin to the diet depressed mestranol O-demethylation, NADPH cytochrome c reductase, and cytochrome P-450 content in a dose related manner up to 2 microgram thiamin per gram of feed. Pair-feeding experiments indicate that thiamin ingestion is responsible for the depression of mestranol O-demethylation and NADPH cytochrome c reductase activity while carbodhydrate ingestion is responsible for the decrease in cytochrome P-450. The absorbance spectra generated by the binding of ethylisocyanide to microsomes yield data which suggest that there are no qualitative alterations in cytochrome P-450 due to diet.

Influence of norethindrone on drug-metabolizing enzymes of female rat liver in various B-vitamin deficiency states

Ingestion of high levels of thiamin significantly decreased the activity of cytochrome P-450, NADPH cytochrome c reductase, and the metabolism of aniline and ethylmorphine. Apparent VmaxS for ethylmorphine N-demethylase and aniline hydroxylase were decreased by high levels of riboflavin even though NADPH cytochrome c reductase was elevated. High levels of dietary pyridoxine significantly decreased only the Vmax for aniline hydroxylase. Generally, norethindrone produces either no change or slight depression of cytochrome P-450 regardless or diet, whereas the administration of norethindrone produced no change or an increase in activity of c reductase and ethylmorphine N-demethylase. Norethindrone induces aniline hydroxylase in animals fed all diets except those deficient in thiamin and riboflavin. The activities of the four parameters of the drug metabolizing system measured in these studies as well as the effects of norethindrone are clearly affected by the dietary status of the animal.

173t, a new antitumor antibiotic. II. Antitumor and toxicological studies

The β-lactamase specified by an R_te16 plasmid in Bordetella bronchiseptica was purified 200-fold by carboxymethyl-Sephadex column chromatography and electrofocusing. The enzyme has a molecular weight of 46,000 ± 3,000 and an isoelectric point of 8.3 and was highly active against phenethicillin, oxacillin, and propicillin. The enzyme activity was inhibited by sodium chloride but not by ferrous ion. The maximal enzyme activity to benzylpenicillin was observed at pH 7.0 to 7.5 and at 40 C. It is concluded that this enzyme is different from the R-mediated β-lactamases, i.e., the type I and type II β-lactamases which have been classified in previous papers.

Thyrotrophin secretion from rat pituitary autografts infused with synthetic thyrotrophin releasing factor

Thyroidal uptake and release of 131I were used to study the response of pituitary autografts to locally infused synthetic thyrotrophin releasing factor (TRF) and porcine median eminence extract (MEE). Thyroidal release rates of 14% 131I/24h were maintained during continuous infusion of grafts with MEE (equivalent to 4 hypothalami/day) while 12·6% 131I/24 h was lost from thyroids of rats whose pituitary autografts were infused with 1000 ng synthetic TRF/day. Infusion of autografts with 5, 50 and 250 ng synthetic TRF/day resulted in lower, but dose-dependent, thyroidal responses suggesting that synthetic TRF could induce thyrotrophin (TSH) synthesis in the grafts.

At all doses of TRF, thyroidal 131I release was significantly increased by daily injection of cortisone (2 mg s.c.).

Local TRF stimulation of TSH release from pituitary grafts significantly increased the dose of thyroxine (T4) needed to decrease thyroid activity, and while 1·0 μg T4/100 g depressed activity in rats receiving saline infusions, 1·7–2·7 μg T4/100 g was needed to inhibit 131I release in rats receiving 250 ng TRF/day, and 3 μg T4/100 g was needed by rats receiving 1000 ng TRF/day.

Continuous TSH infusion (25–28 mu./day) into hypophysectomized rats induced thyroidal 131I release at rates similar to those in rats with TRF-stimulated pituitary autografts.

It is suggested that while synthetic TRF can enhance TSH synthesis in the pituitary its effects on TSH synthesis may normally be potentiated by other humoral substances.

Increase in thyrotrophin secretion by rat pituitary autografts after infusion of hypothalamic extracts

Thyroidal uptake and release of 131I were used to study the effects of prolonged infusion of porcine hypothalamic extract on the ability of rat pituitary autografts to secrete thyrotrophin (TSH). The extract used contained insufficient TSH to induce release of thyroidal 131I in hypophysectomized rats.

After infusion for 10 days, the time of maximal uptake of 131I and onset of 131I release was significantly shortened by infusion of hypothalamic, but not cerebral cortical extract, when compared with non-infused autografted controls. The rate of release of thyroidal 131I was significantly increased by the infusion of hypothalamic extract so that by 96–120 h after the administration of 131I the rate of release was not significantly different from that in intact controls.

Accelerated thyroidal release of 131I began 42–48 h after the application of hypothalamic extracts to pituitary autografts and fell rapidly after withdrawal of the extract. At the end of 14–17 days of infusion sections of the autografts contained aldehyde-fuchsin positive staining basophils.