A 60-kDa phosphorylated protein from fetal human bone

A phosphorylated protein was isolated and purified from fetal human bone. Fetal and adult human bones were decalcified with EDTA, and the extract from the fetal bone was fractionated using Q-Sepharose anion exchange chromatography. The fraction containing Ser(P) was purified by Sephacryl S-200 molecular sieving and C4 reverse-phase HPLC. The purified protein had a molecular weight of 60000 on SDS-PAGE, where the protein was stained with Rhodamine-B. The amino acid composition of this protein was different from any other reported phosphorylated proteins in human bone. However, this phosphorylated protein was difficult to detect in the adult bone extract on SDS-PAGE.

Analysis of thallium-201 myocardial SPECT images using fuzzy set theory

Using the fuzzy set theory, a method was developed for analyzing the extent and severity of ischemia by comparing the exercise and delayed SPECT images with Thallium-201. For each short axial image (slice) for exercise and delayed study, a defect probability matrix (DPM) is created so that it shows the severity of ischemia of myocardium in that slice. Each slice is divided into 8 equi-angle sectors, and the left ventricle (LV) also is divided into 8 equi-angle vertical sectors from apex to base. Using DPMs, the defect probability is calculated for each slice, sectors of each slice and vertical sectors of the LV. The results are displayed on a CRT by means of images, curves and histograms. They show what percentage of the area of each slice and that of the lateral, anterior, septum and inferior portions have how much defect. They provide comprehensive and easily understood information about the condition of the LV in exercise and delayed stages. Persistent and transient ischemia can be diagnosed by visual comparison of patients' curves and histograms with their corresponding normal limits.

Use of ultrasonographic risk score in the timing of operative intervention for acute cholecystitis

Timing of operative intervention for acute cholecystitis has long been a subject of debate. However, actual or impending perforation constitutes an absolute indication for prompt operative intervention. To discriminate these cases from those undergoing observation with conservative treatment, clinical and ultrasonographic findings were reviewed and analyzed in 17 patients with acute cholecystitis. Specificity, sensitivity, and accuracy of ultrasonography in discriminating cases of acute cholecystitis, in terms of timing of operative intervention, were calculated retrospectively based on the operative findings. The risk score for each ultrasonographic finding was determined, and the total risk score was calculated for each patient. The calculated total risk score was found to be well correlated with the macroscopic appearance of the gallbladder at operation in cases of acute cholecystitis. Therefore, this score should be useful in determining the timing of operative intervention for acute cholecystitis. However, the usefulness of the variables should further be established prospectively in other patient populations.

The distribution and propagation pattern of motor unit action potentials studied by multi-channel surface EMG

We developed the multi-channel surface EMG system using a matrix-type of surface electrode and with the aid of digital signal processing. The subjects were 14 normals (4-50 years) and 2 patients with Duchenne muscular dystrophy (7 and 8 years). The biceps brachii and the tibialis anterior muscles were investigated. The location of the motor end-plates and the measurement of muscle fiber conduction velocity were evaluated by the time shift of bipolar EMG arrays along muscle fibers, or by the distribution map of averaged motor unit action potentials (MUAPs). The lateral extension of a motor unit could be also estimated from the changes of averaged MUAP's amplitudes in the distribution map. Moreover in the biceps of 2 patients with Duchenne dystrophy, the mean muscle fiber conduction velocities were reduced compared to normal subjects, and characteristic propagation patterns of action potentials were obtained. In the 2-dimensional or 3-dimensional distribution map of integrated monopolar EMGs, the high density area agreed with the motor end-plate band.

Isolation and chemical characterization of the phosphoproteins of chicken bone matrix: heterogeneity in molecular weight and composition

Ethylenediaminetetraacetic acid and HCl extracts of calcified chicken bone were fractionated by a variety of techniques, including molecular sieving in guanidinium chloride, ion-exchange chromatography on DEAE-cellulose, high-performance liquid chromatography (HPLC), reverse-phase HPLC, and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Using several different experimental schemas, we isolated 14 apparently homogeneous components varying in molecular weight from approximately 150K to approximately 4K-5K. The compositions of all of the phosphoproteins were characterized by high concentrations of Asp, Glu, Ser, Gly, and Ala. Seven of the components which were analyzed contained concentrations of carbohydrate varying from approximately 4% to approximately 17%. Three of the components containing O-phosphoserine which behaved as single bands on SDS-PAGE with molecular weights of approximately 150K, approximately 90K, and approximately 70K contained Hyp and Hyl or Hyl alone and may represent covalently bonded or strongly associated collagen-phosphoprotein complexes or hydroxylated Pro and/or Lys residues of the phosphoproteins. The findings that the amino acid compositions of several of the components were very similar and that N-terminal partial amino acid sequences of the approximately 90- and approximately 60-kilodalton (kDa) and of the approximately 150- and approximately 32-kDa components, respectively, were identical make it clear that some of the lower molecular weight components are derived by proteolysis from higher molecular weight species. In addition to proteolysis, we speculate that it is possible, from the N-terminal amino acid sequence data and preliminary cross-reaction studies of antibodies to four of the phosphoproteins, that the heterogeneity observed in the phosphoprotein components may also be due in part to there being more than one independent gene product for chicken bone phosphoproteins.

Preliminary studies of the secondary structure in solution of two phosphoproteins of chicken bone matrix by circular dichroism and fourier transform-infrared spectroscopy

The secondary structures of two phosphoproteins from chicken bone matrix of Mr approximately 15kDa and approximately 28kDa, rich in Asx, Glx, and Ser, and containing Ser(P) and Thr(P) residues, have been investigated in solution by Circular Dichroism (CD) and Fourier Transform-Infrared Spectroscopy (FT-IR). CD spectroscopy, which yields useful information on the backbone conformation of polypeptides and proteins, suggests a predominantly beta-sheet structure for the two phosphoproteins. The FT-IR spectra of the approximately 15kDa protein, which is sensitive to secondary structure and hence provides complimentary information to CD spectroscopy, are consistent with the results obtained by CD studies.

[Extraction and characterization of phosphoproteins from chicken bone]

EDTA and HCl extracts of chicken bone were fractionated by a variety of techniques, including molecular sieving, ion exchange chromatography, and high performance liquid chromatography. Six different molecular weight phosphoproteins, 13K, 14K, 15K, 28K, 33K, and 70K dalton, were obtained. Further purified fractions were isolated by extraction of single bands from SDS electrophoresis gels. The amino acid composition of these phosphoproteins suggested the origin of the lower molecular weight phosphoproteins from higher molecular weight phosphoprotein during the purification process or maturation of the animal. In those instances, however, the amino acid composition and the degree of phosphorylation varied. This suggested the existence of genetically different phosphoproteins. Molecular weight 70K fraction included collagen component, indicating some of the phosphoproteins strongly bound to the collagen of the bone matrix.

Analysis of pyridinoline, a cross-linking compound of collagen fibers, in human urine

Pyridinoline, a cross-linking compound of collagen fibers, was found in human urine. A significant portion of urinary pyridinoline was in free form. The ratio of total pyridinoline to creatinine changed with age. It was high in children and decreased with growth. It was low and constant in adults, and increased slightly in old age. It was increased significantly in patients with certain bone and joint diseases. Urinary pyridinoline may serve as a useful marker for the breakdown of collagen fibers of skeletal tissues.

Synthesis of pyridinoline during in vitro aging of bone collagen

Pyridinoline is a non-reducible crosslink of collagen. The changes in the content of this crosslink during in vitro aging of bone collagen were studied. The pyridinoline content of bone collagen of 6-week-old chick was very low. When the collagen was incubated with physiological saline in air at 37 degrees C, the pyridinoline content increased markedly. After 6 weeks, the content reached the same level as that of the adult. The synthesis of pyridinoline was inhibited when air was excluded. The in vitro aged collagen was less susceptible to pepsin than the untreated collagen. The results indicate that pyridinoline is one of the mature crosslinks of collagen and plays a role in the stabilization of collagen fibers.