Overproduction of alpha chains provides a proton-insensitive component to the bluefish hemoglobin system.

Expression of alpha and beta chains and their post-translational assembly into alpha(2)beta(2) tetramers is fundamental to the formation and function of most vertebrate hemoglobins. There is a strong evolutionary bias that favors expression of equal amounts of the two types of chains, because cooperativity, pH sensitivity, and anionic control of function occurs only for the alpha(2)beta(2) tetramers. Remarkably, an over-production of alpha chains, as in the pathological condition known as beta thalassemia in humans, is adaptive rather than pathological in the bluefish hemoglobin system.

Responses of normal and sickle cell hemoglobin to S-nitroscysteine: implications for therapeutic applications of NO in treatment of sickle cell disease.

Factors which govern transnitrosation reactions between hemoglobin (Hb) and low molecular weight thiols may define the extent to which S-nitrosated Hb (SNO-Hb) plays a role in NO in the control of blood pressure and other NO-dependent reactions. We show that exposure to S-nitrosylated cysteine (CysNO) produces equivalent levels of SNO-Hb for Hb A(0) and sickle cell Hb (Hb S), although these proteins differ significantly in the electron affinity of their heme groups as measured by their anaerobic redox potentials. Dolphin Hb, a cooperative Hb with a redox potential like that of Hb S, produces less SNO-Hb, indicating that steric considerations outweigh effects of altered electron affinity at the active-site heme groups in control of SNO-Hb formation.

Internal electron transfer between hemes and Cu(II) bound at cysteine beta93 promotes methemoglobin reduction by carbon monoxide.

Previous studies showed that CO/H2O oxidation provides electrons to drive the reduction of oxidized hemoglobin (metHb). We report here that Cu(II) addition accelerates the rate of metHb beta chain reduction by CO by a factor of about 1000. A mechanism whereby electron transfer occurs via an internal pathway coupling CO/H2O oxidation to Fe(III) and Cu(II) reduction is suggested by the observation that the copper-induced rate enhancement is inhibited by blocking Cys-beta93 with N-ethylmaleimide.

Plantar fibromatosis of the heel in children: a report of 14 cases.

Based on a study of 14 patients younger than 16 years, we found that lumps on the plantar aspect of the anteromedial portion of the heel pad can safely be observed. Many remained small and asymptomatic, some disappeared, and two that required repeated excision biopsy did not subsequently recur. The six patients who were subjected to excision biopsy were found to have plantar fibromatosis.

Biomechanical effects of gamma irradiation on fresh frozen allografts in vivo.

The effect of gamma irradiation on the mechanical properties of allograft in a rabbit model was examined. Tibial allografts were tested in torsion to failure to determine maximum torque and maximum stress. Statistically significant degradation in the torsional strength of irradiated tibias vs controls was demonstrated.

A carbon monoxide irreducible form of cytochrome c oxidase and other unusual properties of the "monomeric" shark enzyme.

Contrary to previous reports, the functional and spectral properties of "monomeric" shark cytochrome c oxidases are not entirely similar to those of the "dimeric" beef enzyme. Most significantly, unlike the behavior of beef oxidase, the fully oxidized shark enzyme is not reducible by carbon monoxide. Also, preparations of the shark enzyme, isolated at pH 7.

The site of the redox-linked proton pump in eukaryotic cytochrome c oxidases.

The electronic spectra of fully oxidized derivatives of some cytochrome c oxidase preparations are distinctly pH dependent. In general, the observed spectral shifts are greater in the case of pulsed derivatives compared to resting preparations and also, greater for preparations of the enzyme from shark skeletal muscle compared to beef heart. The low temperature near-infrared magnetic circular dichroism spectrum of the fully oxidized shark enzyme is not pH dependent in the experimental range, indicating the sensitivity of the visible region electronic spectrum to variation in pH to be due principally to changes at the heme a3-CuB chromophore.

Surgical correction of congenital kyphosis in myelomeningocele.

A progressive kyphosis in myelomeningocele patients may occur when the lesion is in the lower thoracic spine (i.e., a high-level lesion).

Is pinning in situ a safe procedure for slipped capital femoral epiphysis?

This report reviews the results of 37 patients with 46 involved hips treated with pinning for slipped capital femoral epiphysis. Particular attention was given to incidence of complications, including avascular necrosis, chondrolysis, and penetration of the joint. Of 46 hips with 1-year follow-up, there were no cases of chondrolysis.

Medial triceps flap coverage for an ulnar neuroma.

This paper reports on a technique for coverage of a posttraumatic lateral neuroma at the elbow. A 14-year-old male patient underwent exploration of the ulnar nerve 4 months after a laceration to the elbow. Following neurolysis and anterior submuscular transposition, the exposed neuroma was covered using a flap of medial triceps muscle.

Percutaneous screw fixation of intercondylar fracture of the distal humerus.

A greenstick intercondylar fracture of the distal humerus occurred in a 13-year-old boy. The articular surface of the trochlea was diastased nearly 5 mm. The fracture was reduced and fixed percutaneously using a 4.

Synergistic effects of vinblastine and recombinant interferon-beta on renal tumor cell lines.

Potential synergistic interactions between vinblastine (VBL) and recombinant interferon-beta (rIFN-beta) were assessed using median effect analysis. Calculation of the combination index demonstrated values less than 1 (indicating synergy) over a wide range of drug-induced growth inhibition for each of four different renal carcinoma cell lines (RCC). The degree of synergy observed could not be predicted from the morphology, doubling time, or relative sensitivity of the RCC lines to VBL and rIFN-beta.

Isolation, purification and characterization of an iron-binding protein from the horseshoe crab (Limulus polyphemus).

The presence of an iron-binding protein in the haemolymph of the horseshoe crab, Limulus polyphemus, was detected by gel filtration of 59Fe-labelled haemolymph. Lysis of amoebocytes did not change the amount of iron-binding protein in haemolymph samples. The protein was purified to homogeneity by ion-exchange chromatography.

Hemocyanin of the horseshoe crab, Limulus polyphemus. Structural differentiation of the isolated components.

The high molecular weight hemocyanin found in the hemolymph of the horseshoe crab, Limulus polyphemus, is composed of at least eight different kinds of subunits. Ion exchange chromatography at high pH in the presence of EDTA yields five major zones, hemocyanins I to V, three of which are electrophoretically heterogeneous. The subunits have similar molecular weights, 65,000 to 70,000, and their amino acid compositions are remarkably similar to each other and to other arthropod and molluscan hemocyanins.

Hemoglobin Deer Lodge (beta 2 His replaced by Arg). Consequences of altering the 2,3-diphosphoglycerate binding site.

Hemoglobin Deer Lodge is an abnormal human hemoglobin with arginine substituted for histidine at the beta 2 position. X-ray crystallography of normal human hemoglobin has shown that the beta 2 residue is normally part of the binding site for 2,3-diphosphoglycerate. The substitution of arginine for histidine at beta 2 affects both the kinetics and equilibria of ligand binding.