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Biomedical subjects

H Shindo

Publications and source records attributed to H Shindo.

At least 199 records · Page 11Linked to original sources
PubMed1977

Muscle load and fatigue of film rolling workers.

Effects of locally concentrated loading by repetitive upper limb operations on the musculature were studied in female workers of ages 19--33 rolling photographic film. They repeated rolling and capping of a 35 mm film every 2.5--5 sec during the whole day shift which had a 60 min lunch recess and two 10 min rests. Increase of dull-drowsy symptoms and shoulder complaints was dominant after work, stiff shoulders complaints being divided into 41.6% for prework and 78.7% for postwork. It was characteristic for these workers to have the trapezius muscle showed continuous electromyographic activities in sustaining arms. The average level of the contraction was estimated at about 10--30% of the maximum contraction. Eighty-four per cent of those studied had tenderness at the ascending part of the trapezius, while the same tenderness was found in only 48% of female office workers of the same firm. The operators having low tenderness threshold of 0.6 kg/cm2 or less had stiff shoulders more frequently as well as lower levels of back muscle and upper arm abduction forces than those having no tenderness. It is thus likely that habitual shoulder muscle fatigue is due to repetitive tasks that results in localized tenderness and possibly in occupational hazards.

Adult↗
PubMed1976

Nuclear magnetic resonance titration curves of histidine ring protons. A direct assignment of the resonances of the active site histidine residues of ribonuclease.

One of the four titrating histidine ring C-2 proton resonances of bovine pancreatic ribonuclease has been assigned to histidine residue 12. This was accomplished by a direct comparison of the rate of tritium incorporation into position C-2 of histidine 12 of S-peptide (residues 1 to 20) derived from ribonuclease S, with the rates of deuterium exchange of the four histidine C-2 proton resonances of ribonuclease S under the same experimental conditions. The same assignment was obtained by a comparison of the NMR titration curves of ribonuclease S, the noncovalent complex of S-peptide and S-protein (residues 21 to 124) with the results for the recombined complex in which position C-2 of histidine 12 was fully deuterated. The second active site histidine resonance was assigned to histidine residue 119 by consideration of the NMR titration results fro carboxymethylated histidines and 1-carboxymethylhistidine 119 ribonuclease. This assignment is a reversal of that originally reported, and has important implications for the interpretation of NMR titration data of ribonuclease.

Binding Sites↗
PubMed1976

Nuclear magnetic resonance titration curves of histidine ring protons. Ribonuclease S-peptide and S-proteins.

The histidine C-2 proton NMR titration curves of ribonuclease S-peptide (residues 1 to 20) and S-protein (residues 21 to 124) are reported. Although S-protein contains 3 histidine residues, four discrete resonances are observed to titrate. One of these arises from the equivalent histidine residues of unfolded S-protein. The variation in area of the four resonances indicate that there is a reversible pH-dependent equilibrium between the folded and unfolded forms of S-protein, with some unfolded material being present at most pH values. Two of the resonances of the folded S-protein can be assigned to 2 of the histidine residues, 48 and 105, from the close similarity of their titration curves to those in ribonuclease. These similarities indicate a homology of portions of the folded conformation of S-protein to that of ribonuclease in solution. These results indicate that the complete amino acid sequence is not required to produce a folded conformation similar to the native globular protein, and they appear to eliminate the possibility that proteins fold from their NH2 terminus during protein synthesis. The low pH inflection present in the titration curve assigned to histidine residue 48 in ribonuclease is absent from this curve in S-protein. This is consistent with our previous conclusion that this inflection arises from the interaction of histidine 48 with aspartic acid residue 14, which is also absent in S-protein. The third titrating resonance of native S-protein is assigned to the remaining histidine residue at position 119. The properties of this resonance are not identical with either of the titration curves of the active site histidine residues 12 and 119 of ribonuclease. The resonance assigned to histidine 119 is the only one significantly affected on the addition of sodium phosphate to S-protein, indicating that some degree of phosphate binding occurs. In both the absence and presence of phosphate this curve also lacks the low pH inflection observed in the histidine 119 NMR titration curve in ribonuclease. This difference presumably arise from a conformational between ribonuclease and the folded S-protein involving a carboxyl group.

Animals↗
PubMed1976

Observation of individual carboxyl groups in hen egg-white lysozyme by use of high field 13C-nuclear magnetic resonance.

Several of the carboxyl carbon atom resonances of hen egg-white lysozyme (mucopeptide N-acetylmuramoyl hydrolase, EC 3.2.1.17) have been resolved by 13C-nuclear magnetic resonance (NMR) at 68 MHz. The change in chemical shift of the carboxyl carbon atom resonances, as a function of pH, has enabled the distinction of these resonances against the background of many nontitrating carbonyl group resonances. Several apparent microscopic ionization constants have been determined from the carboxyl group NMR titration curves, and possible assignments are discussed. Preliminary experiments were carried out in the presence of cobaltous ion, and selective shifts of several resonances were observed. Our results indicate the possibility of the direct observation of a wide range of single functional groups of proteins in solution by NMR techniques.

Animals↗
PubMed1975

Nuclear magnetic resonance titration curves of histidine ring protons. Conformational transition affecting three of the histidine residues of ribonuclease.

NMR titration curves are reported for the 4 histidine residues of ribonuclease A in sodium acetate and for ribonuclease S in sodium acetate, phosphate, and sulfate solutions. Evidence is presented that the imidazole side chain of histidine residue 48 undergoes a conformational change, probably also involving the carboxyl side chain of aspartic acid residue 14. This group is considered to be responsible for the low pH inflection with pKa 4.2 present in the NMR titration curve of the C-2 proton resonance of histidine 48. The NMR titration curves of the active site histidine residues 12 and 119 also exhibit inflections at low pH values, although there is no carboxyl group within 9 A of the imidazole side chain of histidine residue 12 in the structure of ribonuclease S determined by x-ray crystallography (Wyckoff, H. W., Tsernoglou, D., Hanson, A. W. Knox, J. R., Lee, B., and Richards, F. M. (1970) J. Biol. Chem. 245, 305-328). Curve fitting was carried out on 11 sets of NMR titration data using a model in which the 3 histidine residues 12, 119, and 48 are assumed to be affected by a common carboxyl group. The results obtained indicate that such a model with fewer parameters gives as good a representation of the data as the model in which each histidine residue is assumed to interact separately with a different carboxyl group. Therefore, it is concluded that the ionization of aspartic acid residue 14 is indirectly experienced by the active site histidine residues through the conformational change at histidine 48. A model assuming mutual interaction of the active site histidine residues does not account for the low pH inflections in these curves.

Acetates↗