A new method of deriving velocity and acceleration curves for height from the kernel estimation of distance

Further development of the optimal kernel (OK) method of growth curve analysis of Gasser et al. (1984b) is presented with the aim of eliminating the necessity of repeated changes in bandwidth to suit different characteristics of the velocity and acceleration curves at varying ages. After using the OK method to obtain a distance curve for height, we introduce a new method (VADK) to derive velocity and acceleration curves from the fitted distance curve. The results from growth data on 16 boys and 15 girls from the Edinburgh Longitudinal Study are presented in a preliminary test of this method in comparison with the OK estimation.

Single-dose pharmacokinetics of pravastatin and metabolites in patients with renal impairment

The disposition of a single 20-mg oral dose of pravastatin was assessed in subjects with various degrees of renal function. Sixteen subjects (13 males, 3 females) with creatinine clearance values ranging from 15 to 112 mL/min/1.73 m2 completed the study. Area under the serum concentration-time curve, maximum serum concentration, time to maximum serum concentration, terminal serum elimination half-life, apparent clearance, and apparent volume of distribution for pravastatin were not affected by renal impairment, whereas the renal clearance of pravastatin decreased as creatinine clearance decreased (r2 = 0.697, P less than .001). The area under the serum concentration-time curve and time to maximum serum concentration of SQ 31,945 (a hepatic metabolite) increased in patients with renal impairment, whereas the terminal elimination rate constant and renal clearance of SQ 31,945 significantly decreased as a function of creatinine clearance. The renal clearance of another metabolite (SQ 31,906) also significantly declined with decreasing renal function. This single-dose study demonstrates that pravastatin pharmacokinetics were not affected in patients with renal impairment, probably because of its dual route of elimination.

Identification of the DNA-binding domain of the FLP recombinase

We have subjected the FLP protein of the 2-micron plasmid to partial proteolysis by proteinase K and have found that FLP can be digested into two major proteinase K-resistant peptides of 21 and 13 kDa, respectively. The 21-kDa peptide contains a site-specific DNA-binding domain that binds to the FLP recognition target (FRT) site with an affinity similar to that observed for the native FLP protein. This peptide can induce DNA bending upon binding to a DNA fragment containing the FRT site, but the angle of the bend (approximately 24 degrees) is smaller in magnitude than that induced by the native FLP protein (60 degrees). The additional DNA bending induced by the interaction between two native FLP molecules bound to the FRT site is not observed with the 21-kDa DNA-binding peptide. Amino-terminal sequencing has been used to map this peptide to an internal region of FLP that begins at residue Leu-148. It is likely that the DNA-binding peptide includes the catalytic site of the FLP protein.

Erythrocyte vesiculation in paroxysmal nocturnal hemoglobinuria

Red blood cells from patients with paroxysmal nocturnal hemoglobinuria (PNH) were found to be liable to vesiculate, as demonstrated by both DMPC liposome- and CaCl2-induced vesiculation and measured in terms of acetylcholinesterase activity and 3H-inositol radioactivity in the supernatant. Membrane proteins released from the cells during vesiculation included several constituents with molecular weights identical to those of some complement regulating factors (e.g. DAF) which play an essential role in complement-mediated hemolysis. Red blood cells from both normal and PNH patients showed decreased deformability after vesiculation. Liability to vesiculate and the consequential loss of certain essential membrane proteins and decreased deformability might be a factor contributing to the mechanism of hemolysis in PNH.

Antioxidant action of certain simple phenolic compounds derived from Chinese herbs

H2O2 and hydroxyl free radical active oxygen generation systems were utilized to define the antioxidant activities of simple phenolic compounds derived from Chinese herbs. Although the antioxidant activities of compounds differed when assessed in the two systems, all compounds tested were found to be effective at preventing red blood cell membrane lipid peroxidation, with the propyl and butyl esters of gallic acid being especially potent. No compound was able to prevent hemoglobin oxidation. All compounds but salicylic acid were found to interact dose-dependently with H2O2 and hydroxyl free radical as determined by a chemiluminescence method.

Physiological role of vitamin A in growth cartilage cells: low concentrations of retinoic acid strongly promote the proliferation of rabbit costal growth cartilage cells in culture

We have demonstrated that high concentrations of retinoic acid (RA) inhibit expression of the differentiated phenotypes of rabbit costal chondrocytes in culture [M. Takigawa et al. (1980) Proc. Natl. Acad. Sci. U.S. 77, 1481-1485]. In this study we examined the effects of low concentrations of RA on rabbit costal chondrocytes cultured in medium containing vitamin A-deficient serum. In vitamin A-deficient medium, chondrocytes isolated from growth cartilage (GC) proliferated only very slowly, and RA strongly stimulated their proliferation. This stimulatory effect was observable at a concentration of 10(-10) M RA and maximal at a concentration of 10(-8) M. RA at 10(-8) M did not change GC cells from a typical polygonal shape to fibroblast-like cells or inhibit their synthesis of type II collagen. Moreover, RA-treated cells did not synthesize type I collagen. RA inhibited glycosaminoglycan (GAG) synthesis by the cells dose-dependently, but did not change the distribution profile of proteoglycan monomers as determined by glycerol gradient centrifugation. The inhibitory action of RA on GAG synthesis was reversible: after removal of RA from the culture, the rate of GAG synthesis increased within 2 days. In contrast, resting cartilage (RC) cells proliferated well in vitamin A-deficient medium without addition of RA, and RA (10(-8) M) stimulated their proliferation only slightly. Furthermore, the inhibitory effect of RA on GAG synthesis in RC cells was much weaker than that in GC cells. These observations suggest a physiological role of RA in cartilage in stimulating the proliferation of GC cells without causing drastic change in their differentiated phenotypes.

[Radiotherapy of olfactory neuroblastoma--report of 5 patients]

Olfactory neuroblastoma is a rare tumor arising from the olfactory mucosal epithelium. 5 patients with this tumor were treated in our hospital from 1978 to 1982. The youngest patient was 3 years old and the eldest was 66. The clinical symptoms were nasal stuffiness, rhinorrhea, epistaxis and vascular polypoid mass in the nasal cavity. According to the staging system proposed by Kadish et al, the five patients in this series were 3 stage A and 2 stage C patients. Treatment consisted of radiotherapy, surgery or combination of radiotherapy and surgery. Our data indicate that the olfactory neuroblastoma is a radiosensitive tumor with the prognosis favorable in the stages A and B patients as treated by these three modalities. Two stage A patients are alive for more than 5 years. One of them was treated by radiotherapy alone, the other by combination of surgery and radiation. The third stage A patient as treated by radiotherapy alone has survived more than 3 years. One stage C patient, treated by combination of radiation and surgery, is still alive for more than 3 years. The other stage C patient, treated by radiotherapy alone, had survived for only 7 months after the treatment. The radiation dose varies with the extent of invasion. In stages A and B lesions, a dose of 4,500-5,500 rad in 5 weeks may be reasonable but in stage C, a dose of 6,000-6,500 rad in 7 weeks should be given. The authors agree to the prognostic equation proposed by Homzie et al. It may be possible to predict the tumor control or recurrence after a period of 3 years which gives an accuracy rate of 87%.

Purification and characterization of two forms of a low-affinity Ca2+-ATPase from erythrocyte membranes

A low-affinity Ca2+-ATPase from erythrocyte membranes has been purified by agarose suspension electrophoresis and polyacrylamide gel electrophoresis in the absence of detergents. For maximal activity a calcium concentration above 10 mM is required. The activity is independent of magnesium. The Km value for ATP is about 60 microM. The enzyme appears in two forms (A and B) with similar amino acid composition. The specific activity of A is higher than that of B. Gel electrophoresis in SDS of A gives a pattern consisting of two bands. B gives the same pattern; the only difference between the patterns is the ratio of the amounts of protein in the bands. The apparent molecular weight of the proteins in the two SDS bands has been estimated at 23000 and 21000, respectively. The results obtained can be explained by assuming that the two proteins corresponding to the two bands obtained in SDS electrophoresis have a similar structure and can associate to complexes A and B. We have also shown that electrophoretic and chromatographic supporting media can induce aggregation of (membrane) proteins. Artificial complexes can thus be formed and cause misinterpretation of the data obtained. This may be the reason why some authors have speculated that Ca2+-ATPase is active only in complex with other proteins such as spectrin and actin.