Phase matching in birefringent fibers

We describe a new technique that utilizes birefringence for phase matching of stimulated parametric emission in a single-mode optical fiber. The frequency shift between the generated frequencies and the pump frequency can be controlled over a wide range (approximately 1000 cm(-1)) by the magnitude of birefringence built into the fiber.

Optical-pulse equalization of low-dispersion transmission in single-mode fibers in the 1.3 - 1.7-microm spectral region

We describe a simple optical-pulse-equalization technique for minimizing pulse dispersion in a single-mode fiber transmission system utilizing the positive- and the negative-dispersion characteristics of single-mode fibers on both sides of a zero-chromatic-dispersion wavelength.

High-pressure liquid chromatographic method for determination of rosaramicin in humans

A high-pressure liquid chromatographic method has been developed for the quantitative determination of rosaramicin in serum. This procedure involves addition of an internal standard, adjustment to alkaline pH, treatment with potassium carbonate, ether extraction, and a reverse-phase column separation with acetonitrile-acetate buffer mixture as the mobile phase. This technique produces a good linear relationship between the peak height ratio and the rosaramicin concentration. In addition, this method has proven to be quite specific for rosaramicin, since many of its derivatives tested do not interfere with the assay. The method is accurate and reproducible with a sensitivity of about 0.01 microgram of rosaramicin per ml of serum. It may be useful in monitoring drug levels in serum of patients and also for the pharmacokinetic studies of the drug in humans.

Direct demonstration of distortionless picosecond-pulse propagation in kilometer-length optical fibers

We describe the use of a mode-locked color-center laser to demonstrate nearly distortionless propagation of ~5-psec-wide, Fourier-transform-limited pulses, at or near the zero-dispersion wavelength, in two fused-silica, singlemode fibers of 0.76- and 2.5-km length, respectively. We also report the detection of sharply defined cross correlations between pulses directly from the laser and those had been delayed many microseconds by passage through a fiber.

Reduction of GTP activation of adenylate cyclase system by its coupling to hormone receptor

We have examined the characteristics of the adenylate cyclase system from control and butyrate-treated cells. Butyrate treatment results in both an increased number of catecholamine receptors and an induction of a response to the hormone, as reported previously (Tallman, J.F., Smith, C.C., and Henneberry, R.C. (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 873-877); in addition, we found that the same treatment reduces the degree of activation of adenylate cyclase by GTP. We have demonstrated in two cell types that this decrease in GTP activation is inversely related to the degree of induction of the hormone response. Furthermore, in plasma membranes isolated from butyrate-treated cells, the hormone receptor is sensitive to GTP; i.e. GTP reduces the affinity of isoproterenol for the receptor. We propose that these changes reflect an interaction between the beta-adrenergic receptor and the nucleotide regulatory component and that this interaction represents, at least in part, the process of coupling. Several possible mechanisms which can account for the change in GTP activation are discussed in terms of our current understanding of the regulation of the adenylate cyclase system.

Absorption, metabolism, and excretion of 14C-tosifen in the dog and rat

14C-tosifen [N-2-(1-phenylpropyl)-N'-p-tolyl sulfonylurea] was readily absorbed in both rats and dogs. The rates of absorption, metabolism, and urinary excretion were higher in the rat than in the dog. More of the drug was excreted via the feces than in the urine of the rat, whereas in the dog, the drug was primarily excreted into the urine. The parent drug was the major radioactive component in the plasma of both species. In the urine, however, only a negligible amount of tosifen was found. The major urinary metabolite was a hydroxymethyl derivative which accounted for about 60% and 40% of the total radioactivity in the urine of the dog and rat, respectively.

Pulse delay measurements in the zero material dispersion wavelength region for optical fibers

Subnanosecond pulses in the 1120-1550-nm region are generated by multiple-order stimulated Raman scattering in a small core single-mode silica fiber pumped by a Q-switched and mode-locked Nd:YAG laser at 1064 nm. These near ir pulses are injected into various km long test fibers, and relative time delay changes between different wavelengths are used to determine dispersion in a region where fiber material dispersion is small. Zero material dispersion has been observed in germanium and boron-doped single-mode and multimode est fibers.

A cw tunable near-infrared (1.085-1.175-microm) Raman oscillator

This is the first report of a cw tunable Raman laser in the 1.1-microm region of the spectrum. A prism-tuned fiber Raman resonator with a 650-m-long, low-loss small-core single-mode silica fiber was pumped by a 5-W cw Nd:YAG laser at 1.064 microm. With two separate resonator mirrors for the first and the second Stokes oscillation, we have obtained first Stokes oscillation tunable from 1.085 to 1.13 microm and second Stokes oscillation tunable from 1.15 to 1.175 microm.

Isolation and identification of the major metabolite of albuterol in human urine

The major urinary metabolite of albuterol in man was isolated and purified by ion-exchange chromatography and countercurrent distribution. On the basis of proton magnetic resonance, infrared, and mass-spectral analysis, enzymic hydrolysis, and assay of inorganic sulfate after acid hydrolysis, the metabolite has been identified as the 4'-O-sulfate ester of albuterol.

Routine amnioscopy at term

A controlled study for the management of antepartum meconium-stained amniotic fluid (MSAF) detected by amnioscopy performed in a total of 508 patients is presented. The incidence of antepartum MSAF was 2.2%, while intrapartum MSAF was found in 15% of cases. A significant incidence of depressed neonates was found in the latter group. Patients with antepartum MSAF had no perinatal losses, whether managed expectantly or by oxytocin induction. Immediate operative intervention (ie, cesarean section) is not warranted. Observations on FHR patterns, fetal pH, and Apgar scores of these patients are presented.

Correlation of 14C-griseofulvin metabolism in rat liver microsomes, isolated perfused rat livers, and in rats with bile duct cannulas

The metabolism of 14C-griseofulvin has been compared in rat liver microsomes, isolated perfused rat livers, and rats with bile duct cannulas. In all three preparations, 4-desmethylgriseofulvin and 6-desmethylgriseofulvin were the major metabolites. The ratio of total 4-desmethylgriseofulvin to 6-desmethylgriseofulvin formed was 1.20, 0.89, and 1.01 in liver microsomes, isolated perfused livers, and rats with bile duct cannulas, respectively. After a 7-min incubation with liver microsomes, most (96%) of the griseofulvin remained unchanged. Only small amounts of 4-desmethylgriseofulvin (1.26%) of dose) and 6-desmethylgriseofulvin (1.05% of dose) were formed. In isolated perfused liver, most of the drug (59% of dose) was excreted into bile within 4 hr, primarily as 4-desmethylgriseofulvin (24% of dose) and 6-methylgriseofulvin (24% of dose). In animals with bile duct cannulas, 65% of the dose was excreted into bile and 18% of the dose into urine within 4 hours. In bile, 32% of the dose was excreted as 4-desmethylgriseofulvin and 20% of the dose as 6-desmethylgriseofulvin, whereas in urine the drug was excreated predominantly as 6-desmethylgriseofulvin (13% of dose) with only a small amount of 4-desmethylgriseofulvin (1% of dose), during the first 4 hr. These results show that there is good correlation in the metabolic fate of 14C-griseofulvin in the liver microsomes, isolated perfused liver, and rats with bile duct cannulas. In addition to the similar ratio of 4-desmethylgriseofulvin to 6-desmethylgriseofulvin, there is also an agreement in the extent of metabolism and biliary excretion in isolated perfused liver and in rats with bile duct cannulas, which suggests that the isolated perfused liver is an important technique for studying drug metabolism in animals.

Electron microscopy of albumin synthesis

Albumin molecules appeared to be synthesized in the light hepatocytes of rats by bound polysomers on rough and endoplasmic reticulum and the nuclear envelope. The molecules were discharged directly into the cytosol, then to the external cellular spaces. This conclusion failed to support the current theory from biochemical studies that albumin is synthesized by bound ribosomes, discharged into the cisternae of rough endoplasmic reticulum, and transported to the smooth endoplasmic reticulum and then to the Golgi apparatus. In addition to the liver, positive syntheic activities were observed in the aorta, kidney, and hepatoma cells of rat. Earlier investigators have reported that only liver cells can synthesize albumin.

Ureteral obstruction from metastatic breast carcinoma

Metastases from carcinoma of the breast may involve one or both ureters, and may be a clinically important phenomenon. Two cases are presented and the autopsy experience with 181 cases of metastatic breast carcinoma is reviewed. Ureteral involvement was demonstrated in 8.3% of the cases. Bilateral metastases were common.

Calcitonin inhibition of bone cell metabolism in vivo: an experimental study in dogs

Calcitonin (CT) has been shown to act by decreasing the output of calcium from the bone, but the precise mechanism that brings about this change is still not fully understood. The present investigation was designed to study the effect of CT on the metablic activity of bone cells, utilizing changes in oxygen consumption and carbon dioxide production as indices of tissue metabolism. Arterio-venous gradients of calcium, inorganic phosphate, hydroxyproline, oxygen, carbon dioxide and hydrogen ions were studied across the canine femur. The results showed that the hypocalcemic action of CT was accompanied by a corresponding decrease in free hydroxyproline output from the bone, demonstrating that decreased bone resorption was responsible for the fall in plasma calcium levels. Reduced oxygen consumption and decreased carbon dioxide production by the bone showed that CT acted by inhibiting the metabolic activity of bone cells in vivo. It is speculated that CT may have acted by depressing mitochondrial respiration.

An empirical method of grouping genotypes based on a linear function of the genotype-environment interaction

The regression approach for analysing genotype-environmental interaction is extended to include the grouping of genotypes. An unweighted pair-group cluster analysis was applied to a special dissimilarly index, derived from the test statistic for differences among regressions. The resulting groups reflect the general pattern of response to the various environments. The data of Yates and Cochran (1938) were used to illustrate the clustering process.