Molecular cloning and expression of a complementary DNA for inositol 1,4,5-trisphosphate 3-kinase

A complementary DNA (cDNA) clone that encodes inositol 1,4,5-trisphosphate 3-kinase was isolated from a rat brain cDNA expression library with the use of monoclonal antibodies. This clone had an open reading frame that would direct the synthesis of a protein consisting of 449 amino acids and with a molecular mass of 49,853 daltons. The putative protein revealed a potential calmodulin-binding site and six regions with amino acid compositions (PEST regions) common to proteins that are susceptible to calpain. Expression of the cDNA in COS cells resulted in an approximately 150-fold increase in inositol 1,4,5-trisphosphate 3-kinase activity of these cells.

Detection of human papillomavirus (HPV) DNA in laryngeal papilloma

Laryngeal papillomas are troublesome benign tumors of the larynx. According to their biological behavior, there are two types of laryngeal papillomas--the juvenile and adult types. Two samples of adult-type and five samples of juvenile-type laryngeal papilloma specimens were studied using the Southern blot technique with radioactively labeled human papillomavirus (HPV) 6b, 16, 18 deoxyribonucleic acid (DNA) as probes. We found that there was a linear form, an episomal form, and a concatemer or catenane of HPV DNA in the 5 samples of juvenile laryngeal papilloma and there was no evidence of HPV DNA integration. The HPV DNA in tumor cells is very closely associated with HPV 6b, but has no positive hybridization with HPV 16 and 18 DNA even in a low stringent condition. There was no positive hybridization found in the 2 samples of adult-type laryngeal papilloma with any of the three probes.

Cardiovascular effects of two disulfide analogues of sarafotoxin S6b

Sarafotoxin S6b (STX-b), a peptide toxin isolated from the venom of the Israeli burrowing asp, Atractaspis engaddensis, consists of 21 amino acid residues with four cysteines at positions 1,3,11 and 15. In the present study, we compared the cardiovascular effects of two synthetic STX-b analogues with different disulfide bridge locations, i.e. STX-b type A (1-15, 3-11) and STX-b type B (1-11, 3-15). At doses of 0.3-3 nmoles/kg (i.v.), type A produced a sustained pressor effect with transient increase in pulse pressure. However, at 5 nmoles/kg, it produced a transient increase followed by decrease in blood pressure, heart rate and respiratory rate within 30 sec and 12 out of 13 mice died within 10 min. Various kinds of ECG changes, suggestive of myocardial ischemia and hyperkalemia, were observed. Type A also caused a significant increase in the plasma levels of K+, lactate dehydrogenase, creatine phosphokinase, inorganic phosphate and glucose. By contrast, type B did not kill any mouse at doses up to 50 nmoles/kg. In the rat aorta, type A caused a potent vasoconstriction which was dependent on extracellular Ca2+ and was partially inhibited by verapamil and H-7, a protein kinase C inhibitor. In the rat Langendorff heart preparation, type A produced coronary vasospasm with potency about 100 times higher than that of type B. A similar potency ratio was observed for the positive inotropic effect in rat atria. These results indicate that the location of disulfide bridges in sarafotoxin S6b markedly influences the pharmacological potency and the natural sarafotoxin S6b should be type A with the disulfide bridge locations at positions 1-15 and 3-11.

Isolation and characterization of s-myc, a member of the rat myc gene family

A 9-kilobase-pair clone containing a myc-related gene that we have designated s-myc was isolated from a rat genomic library. The entire nucleotide sequence of the cloned DNA was determined, showing that the s-myc gene contains an open reading frame consisting of 1287 base pairs without introns. In vitro transcription-translation analysis of s-myc indicated that this gene produces a protein of approximately 50 kDa. The amino acid sequence predicted from the DNA sequence showed that the s-Myc protein is closely related to the murine N-Myc protein but lacks an acidic amino acid-rich sequence commonly present in the Myc-family proteins. Studies on transfection of s-myc into rat RT4-AC tumor cells revealed that the gene produces a polyadenylylated transcript of approximately 4.7 kilobases and that its high-level expression suppresses the tumor-igenicity of RT4-AC tumor cells in nude mice.

Developmental changes in the activities of phospholipase c, 3-kinase, and 5-phosphatase in rat brain

The specific activities of phospholipase C, 3-kinase, and 5-phosphatase were measured in brain homogenates from rats at different developmental stages. The activities of 3-kinase and 5-phosphatase increased by 14-fold and 2-fold, respectively, during development from fetus to adult, while PLC activity remained constant. These results suggest that the metabolism of inositol phosphates varies widely during development. In young brain stimulated by an agonist, it is predictable that Ins(1,4,5)P3 lasts longer and its average concentration is higher than in adult brain. The opposite is true for both the lifetime and concentration of Ins(1,3,4,5)P4. These developmental changes will invariably affect the property of Ca2+ oscillation and the effective time during which cells respond to the Ca2+-mobilizing agonists.

Intestinal absorption of zinc: sodium-metal-ligand interactions

The characteristics of zinc small intestinal absorption were investigated with the purpose of clarifying the role of sodium and the possible interaction among certain amino acids, oligopeptides, and zinc with electrolyte and water absorption. A perfusion procedure was used in anesthetized rats. Physiological concentrations of zinc with no ligands, or with twice the zinc levels of either Trp, His, Pro, or a protein hydrolysate (PrH) were pumped through jejunal or ileal segments. PrH was also used at a 10: 1 ratio to zinc. The osmotic solutes were either sodium chloride, glycerol, or NMG at isotonic concentrations. In the absence of LMW ligands, zinc transport appeared to occur only by diffusion, except in the ileum and in the presence of glycerol, where at low zinc concentrations a low affinity mediated transport component could be identified (Kt = 0.67 mM; Vmax = 1,160 pmole/min.cm. Glycerol generally elicited a greater overall zinc absorption rate as well as an enhanced net water uptake than when sodium chloride was the osmotic agent when either Trp, His, or Pro was present. The data indicate that sodium is not a requirement for zinc transport. In the presence of LMW ligands, which may also be from endogenous origin, bulk flow may be a major contributor of zinc translocation across the mammalian small intestinal mucosa.

Localized volume selection technique using an additional radial gradient coil

A volume selection technique for the localized NMR imaging using an additional radial gradient is proposed. This volume selection gradient is the fourth gradient in addition to the usual 3-dimensional imaging gradients, i.e., x-, y-, and z-directional gradients, and is of the radial form. The principle of the proposed method is the use of the radial gradient in conjunction with the selective RF pulse thereby selecting a small cylindrical volume which can be used for the 3-dimensional volume imaging with fewer encoding steps than those of the conventional full 3-dimensional volume imaging. The present technique combined with the fast steady state free precession gradient echo imaging sequence allows us to reduce the total scan time to several minutes for the 3-dimensional volume imaging with the spatial resolution of 1 x 1 x 1 mm or to spend the same scan time for the 3-dimensional imaging with improved spatial resolution. The basic principle of the radial gradient coil consisting of a main circular loop coil and an offset compensating Helmholtz coil is discussed and the construction details are presented. Some experimental results of the proposed volume selection imaging technique as well as computer simulation results are also given.

[A community-based study on risk factors of hypertension in Luh-Guu Township]

This is a community-based study on hypertension conducted in 1987 to assess the risk of demographic factors and life style of inhabitants aged over 30 in Luh-Guu Township. One-stage cluster sampling was applied. Through home visit interview, the height, weight, and blood pressure as well as demographic and life style data were taken, and 1171 (57.4%) valid data were completed. Hypertension was defined by American National Heart, Lung, Blood Institute as BP greater than = 140/90mmHg. The prevalence of hypertension was 29.2% (the prevalence was 13.4% if defined by the WHO criteria), and only 27.4% of those hypertensives were self-aware. Univariate analysis found that age, educational level, marital status, job condition, smoking habit, father's hypertension history, and usage of contraceptive were correlated with hypertension. With obesity index in addition to the above 6 factors, except contraceptive usage, as independent variables, the multiple logistic regression analysis showed that, only age and obesity index were significantly correlated with hypertension and the best model were fitted.

The incidence of congenital color deficiency among Koreans

It is important to investigate the incidence of congenital color deficiency and to determine the type and degree because the color deficiency can effect as a handicap to certain occupations. The incidence of congenital color deficiency is remarkably constant among Caucasians but other races show considerable variations. We investigated the incidence of congenital color deficiency among Koreans by the use of H-R-R pseudoisochromatic plates. The present study revealed that the incidence of congenital color deficiency among Koreans was 31.5% (5.90% in men, 0.44% in women).

Programmable quadratic associative memory using holographic lenslet arrays

Programmable higher-order optical interconnections between two-dimensional arrays of neurons are achieved by using holographic lenslet arrays and spatial light modulators. Basic experimental results for two-dimensional quadratic associative memory are reported to demonstrate its feasibility.

Dynamic viscous flow in distensible vessels of skeletal muscle microcirculation: application to pressure and flow transients

Blood flow in the microcirculation of the rat skeletal muscle during transient changes of arterial pressure is analyzed theoretically. Although flow in such small vessels is quasi-steady and has a very low Reynolds number, time-dependent nonuniform flows along the length of the blood vessels can be observed due to vessel distensibility. The governing equations for a single microvessel are derived using previously measured microvessel elasticity, and several solutions to different inflow and outflow pressures and flow conditions are investigated. The results indicate that when such distensible microvessels are subjected to a step increase of arterial pressure, the arterial flow shows a rapid overshoot followed by a progressive decay to steady-state. An arterial step flow induces a different response which takes the form of a monotonically increasing pressure. Pressure and flows are nonuniform along the vessel length during such transients. In-vitro whole organ pressure-flow data are presented in the dilated rat gracilis muscle which qualitatively agree with the theoretical predictions.

Studies of inositol phospholipid-specific phospholipase C

Inositol phospholipid-specific phospholipase C is the enzyme that generates phosphoinositide-derived messenger molecules. Mammalian cells contain at least five immunologically distinct phospholipase C enzymes that appear to be separate gene products. Complete amino acid sequences of four of these isozymes have been established. The overall sequence similarity is surprisingly low for enzymes catalyzing the same chemical reaction: three of them show limited amino acid sequence similarity to each other in two narrow regions, and the fourth enzyme is completely different. The diversity in primary structure together with different regional and cellular expression of the isozymes suggests that each isozyme has a defined function in processing the physiological response of different cell types to a variety of external stimuli and that each is regulated differently.

[Achalasia: report of two cases]

The first case, a two-month-old female infant, had frequent vomiting since 5 days of age. Dilated esophagus with narrowed distal end was noted on barium meal study. Panendoscopic examination revealed dilated esophagus and a pin-head sized, stenotic lumen at 15 cm from the incisor. Under the impression of esophageal stenosis, gastrostomy was performed for feeding. Esophagogram made at 6 months of age demonstrated good patency of the esophagus without stenosis and gastrostomy was subsequently closed at the age of 1 year. Unfortunately, swallowing disturbance had bothered her intermittently since. Barium esophagogram and panendoscopy made 8 years later again revealed distal esophageal obstruction with dilated proximal esophagus. The second case was a two and half year old boy who suffered from frequent regurgitation of undigested food for 6 months. Dilated esophagus with narrowing of the lower end of esophagus was noted on barium meal study. After admission, panendoscopic examination revealed the esophagus was very narrow at 25 cm from incisor and the proximal esophagus was dilated. The esophageal dilatation with mercury-weighted bougies was performed intermittently. At present he is doing well, and a barium meal study showed adequate esophageal emptying.

Fast SSFP gradient echo sequence for simultaneous acquisitions of FID and echo signals

Recently, the gradient echo imaging sequence in conjunction with small flip angle excitations and short repetition times has been widely used for fast NMR imaging. As the repetition time decreases to an extent comparable to the spin-spin relaxation time T2, the residual phase coherency of the transverse spin magnetization tends to form another nuclear signal which is heavily weighted by T2 and similar to a long TR/long TE spin-echo signal. This effect, although expected, has not been utilized in the conventional fast gradient echo imaging. When this residual phase coherency is utilized in conjunction with the fast SSFP (steady-state free precession) technique, both the FID and the echo signals can be obtained. In this paper, we have proposed a new technique by which simultaneous acquisitions of both the FID and the echo signals are possible. Experiments on this fast SSFP mode imaging have shown that the FID signal is T1-weighted while the echo signal is strongly T2-weighted. The flip angle optimal for maximizing signal and related contrast are also studied in conjunction with the proposed sequence and the experimental results are presented.

IgG2 subclass deficiency: IgG subclass assays and IgG2 concentrations among 8015 blood donors

Among the four IgG subclasses in humans, IgG2 is preferentially expressed in antibodies to carbohydrate antigens whereas IgG1 subclass is commonly associated with antibodies to protein antigens. Because of this association with carbohydrate antigens, values for IgG2 in serum are often used as an index of immunocompetence against carbohydrate antigens. To investigate the value of IgG2 measurements in a general population, we have developed a convenient IgG subclass assay, using monoclonal antibodies and particle concentration fluorescence immunoassay. Our assay is specific, precise, convenient, and accurate. When IgG2 concentrations were determined in the serum samples from 8015 adult blood donors, there were more individuals with low IgG2 concentrations than predicted by the log-normal distribution. The observed distribution suggested the presence of a subpopulation with low IgG2 concentration. Because apparently healthy individuals in a general population have low IgG2 concentrations, IgG2 measurements alone may have a limited clinical usefulness as an index of immune function against carbohydrate antigens.