Mortality pattern in babies delivered by cesarean section and vaginal delivery

A total of 7077 cases of delivery were studied in a rural based hospital where most of the mothers come without any antenatal care, from November, 1979 to December, 1980 to observe the mortality pattern in different types of delivery. Only live born babies were included in the study in which the mortality rate in elective cesarean section was found to be nearly equal to that in vaginal delivery. The percentage of mortality was higher (5.4%) in emergency cesarean section-the chief causes being asphyxia neonatorum, low gestational age and low birth weight.

Characterization of the dermatan sulfate proteoglycans, DS-PGI and DS-PGII, from bovine articular cartilage and skin isolated by octyl-sepharose chromatography

Two forms of dermatan sulfate proteoglycans, called DS-PGI and DS-PGII, have been isolated from both bovine fetal skin and calf articular cartilage and characterized. The proteoglycans were isolated using either (a) molecular sieve chromatography under conditions where DS-PGI selectively self-associates or (b) chromatography on octyl-Sepharose, which separates DS-PGI from DS-PGII based on differences in the hydrophobic properties of their core proteins. The NH2-terminal amino acid sequence of DS-PGI from skin and cartilage is identical. The NH2-terminal amino acid sequence of DS-PGII from skin and cartilage is identical. However, the amino acid sequence data and tryptic peptide maps demonstrate that the core proteins of DS-PGI and DS-PGII differ in primary structure. In DS-PGI from bovine fetal skin, 81-84% of the glycosaminoglycan was composed of IdoA-GalNAc(SO4) disaccharide repeating units. In DS-PGI from calf articular cartilage, only 25-29% of the glycosaminoglycan was composed of IdoA-GalNAc(SO4). In DS-PGII from bovine fetal skin, 85-93% of the glycosaminoglycan was IdoA-GalNAc(SO4), whereas in DS-PGII from calf articular cartilage, only 40-44% of the glycosaminoglycan was IdoA-GalNAc(SO4). Thus, analogous proteoglycans from two different tissues, such as DS-PGI from skin and cartilage, possess a core protein with the same primary structure, yet contain glycosaminoglycan chains which differ greatly in iduronic acid content. These differences in the composition of the glycosaminoglycan chains must be determined by tissue-specific mechanisms which regulate the degree of epimerization of GlcA-GalNAc(SO4) into IdoA-GalNAc(SO4) and not by the primary structure of the core protein.

Proteoglycans of bovine articular cartilage. Studies of the direct interaction of link protein with hyaluronate in the absence of proteoglycan monomer

When link protein binds to hyaluronate in the absence of proteoglycan monomer a high molecular weight complex is formed. Two assay procedures have been developed to examine the formation of the complex and the rate and stoichiometry of binding of link protein to hyaluronate in the complex. In the first, the complex is isolated by differential centrifugation, and the stoichiometry of binding of link protein to hyaluronate in the sedimented complex is determined. In the second assay, which involves turbidimetry, the rate of complex formation (delta A420/min) is determined, and the amount of complex formed is determined in terms of the maximum turbidity (A420,max) attained. The effects of temperature, pH, initial total solute concentration, and the ratio by weight of link protein to hyaluronate on the amount of complex formed and on the rate of complex formation were examined. There is a linear correlation between the amount of complex formed as determined by turbidity and by differential centrifugation. Using these assays, we examined the specificity of the binding of link protein to hyaluronate and the capacity of hyaluronate oligosaccharides to competitively inhibit the binding of link protein to hyaluronate. Hyaluronate decasaccharide is the oligosaccharide of minimum size that strongly inhibits the binding of link protein to hyaluronate. Proteoglycan monomers dissociate from hyaluronate as the pH is decreased from pH 7 to pH 5. Turbidimetric studies show that the rate of binding of link protein to hyaluronate increases with decreasing pH. The binding affinity of proteoglycan monomers for hyaluronate is decreased at pH 5, whereas the binding affinity of link protein for hyaluronate is not. This difference in the effect of pH on the stability of binding of link protein to hyaluronate, compared with proteoglycan monomer, explains in part the capacity of link protein to stabilize the binding of proteoglycan monomer to hyaluronate at pH 5.

False-positive serum digoxin concentrations determined by three digoxin assays in patients with liver disease

The incidence and magnitude of false-positive serum digoxin concentrations (SDCs) determined by three digoxin assays in patients with liver disease were studied. Patients with biochemical evidence of liver disease were enrolled in the study if they had never received a cardiac glycoside, were not pregnant, were not receiving spironolactone, did not have moderate to severe renal impairment, and did not have transient elevations in liver function test results. Blood specimens from each patient were assayed for apparent SDCs in triplicate using a fluorescence polarization immunoassay (FPIA, TDx Digoxin II, Abbott) and a digoxin radioimmunoassay (RIA, GammaCoat I125, Clinical Assays) and in duplicate using a fluorometric enzyme immunoassay (Dade Stratus, American Dade). Forty-two patients met the study criteria. The percentage of patients exhibiting detectable apparent SDCs (greater than or equal to 0.2 ng/mL) was 57% with RIA, 55% with FPIA, and 28% with the fluorometric enzyme immunoassay. Apparent SDCs ranged from 0.2 to 0.6 ng/mL (RIA), 0.2 to 1.56 ng/mL (FPIA), and 0.2 to 0.38 ng/mL (fluorometric enzyme immunoassay). Values obtained using the fluorometric enzyme immunoassay were significantly different from the apparent SDCs determined using RIA and FPIA; however, no significant difference was found between the values obtained using RIA and FPIA. Significant correlations were found between the apparent SDCs determined using RIA and serum bilirubin values and between the apparent SDCs determined using the fluorometric enzyme immunoassay and alkaline phosphatase values. Of the three assay methods tested, the fluorometric enzyme immunoassay showed the least cross-sensitivity to digoxin-like immunoreactive substance (DLIS).(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanical characterization of commercially made carbon-fiber-reinforced polymethylmethacrylate

Acrylic bone cement is significantly weaker and of lower modulus of elasticity than compact bone. It is also weaker in tension than in compression. This limits its use in orthopedics to areas where tensile stresses were minimum. Many authors have shown that addition of small percentages of fiber reinforcement by hand mixing improved the mechanical properties significantly but with variable results. In this investigation we have examined the mechanical properties of machine-mixed, commercially available carbon-fiber-reinforced bone cement. Appropriate samples of normal low-viscosity cement and carbon-fiber-reinforced cement were prepared and tested mechanically. Carbon fiber increased the tensile strength and modulus by 30% and 35.8% respectively. The compression strength and modulus, however, increased by only 10.7%. Similarly, bending and shear strengths improved by 29.5% and 18.5%, respectively. Diametral compression strength, which is an indirect measure of tensile strength, however, showed only 6.2% improvement. The maximum temperature rise during polymerization was also reduced significantly by the fiber reinforcement.