Raman-assisted parametric frequency and polarization conversion in a birefringent fiber

Highly efficient energy conversion of the pump into the downshifted parametric Stokes radiation resulting from the phase-matched parametric four-photon mixing and subsequent perpendicular Raman amplification in a birefringent fiber is presented. We also observed significant polarization conversion from the fast y axis to the slow x axis of the birefringent fiber as a consequence of group-velocity-matched perpendicular Raman amplification of the x-polarized parametric Stokes radiation by the y-polarized pump.

A silencer element from the alpha-globin gene inhibits expression of beta-like genes

We have studied the cis and trans interactions of the alpha- and beta-globin genes in a transient expression system. We found that the alpha-globin gene inhibited beta-globin expression in cis but not in trans. The silencer element responsible for this inhibition was localized to a 259-base-pair fragment at the 5' end of the alpha-globin gene.

The elastogenic effect of recombinant transforming growth factor-beta on porcine aortic smooth muscle cells

Transforming growth factor-beta, a peptide growth factor, is known to be a multifunctional regulator of cellular activity. The effect of this growth factor on extracellular matrix formation is well established, but its effects on elastin, a critical component of lung, skin, and blood vessels are unknown. In the present study, by use of an Enzyme-Linked Immunoassay method, we found that transforming growth factor-beta strongly increased elastin production in cultured porcine aortic smooth muscle cells. In a dosage-dependent study, 1.0-10.0 ng/ml transforming growth factor-beta promoted elastin production 2-3 fold. In a time-dependent study, at least an 8 h pre-treatment with 10.0 ng/ml transforming growth factor-beta was required for sustained increases in elastin production. The effects of transforming growth factor-beta on cultured aortic smooth muscle cells suggest that this cytokine may be an important mediator of elastin formation during atherosclerosis and hypertension.

[Prostatic carcinoid and neuroendocrine tumors--a case report]

This paper reports a rare primary prostatic adenocarcinoid tumor confirmed by electron microscopy as well as immunohistochemical method including prostate specific antigen and prostatic acid phosphatase. Electron microscopy showed the presence of neuroendocrine granules in the cytoplasm of some tumor cells and the latter method ruled out the possibility of secondary tumor from other organs. It is noted that prostatic adenocarcinoid tumor is one of the diffuse neuroendocrine system tumors. Although the histogenesis of these tumors is not entirely clear, it is believed to be of multiple origins, and may transform through metaplasia into neoplasm.

Dietary protein, enhancement of N-nitrosomethylurea-induced mammary carcinogenesis, and their effect on hormone regulation in rats

The effect of supplemental dietary protein (casein) fed with high fat diets was investigated using the N-nitrosomethylurea-induced mammary tumor model. Isocaloric diets containing casein and corn oil at 19 and 15% (normal protein-high fat) or 33 and 15% (high protein-high fat) were fed ad libitum to Sprague-Dawley mother rats. Female offspring continued on the diet. Food consumption and growth curves were similar over the entire growth period. N-Nitrosomethylurea (50 mg/kg body weight) or saline was administered at 7 and 8 weeks of age via the tail vein. Dietary protein had no effect on serum prolactin or growth hormone throughout the estrous cycle: Prior to carcinogen administration, at 7 weeks old, proestrus at 5 p.m., serum prolactin was 231.6 +/- 141.0 (SE) ng/ml (12 rats) versus 292.2 +/- 141.0 (13 rats) for normal versus high protein diet groups, respectively. No difference was noted after carcinogen injection at 9, 13, 28, and 33 weeks of age. Similarly no effect was noted on serum growth hormone activity. Tumor latency was 7 weeks and incidence was 100% in normal protein (24 rats) and high protein (39 rats) groups 28 weeks after carcinogen treatment. The number of tumors per rat (4.38 +/- 0.37 versus 2.87 +/- 0.35, P less than 0.002) and average tumor weight (17.97 +/- 2.63 versus 9.94 +/- 2.92 g) were significantly greater in the high protein group. Study indicates that diet or carcinogen treatment did not alter hormone regulation during the estrous cycle. However, supplemental dietary protein increased the effect of high fat diets enhancing the mammary tumor burden.

Effect of dietary protein on morphologic development of rat mammary gland

Isocaloric diets, containing 8% casein [low protein (LP)], 19.5% casein [normal protein (NP)], or 31% casein [high protein (HP)] and 10% corn oil, were fed to adult virgin female Sprague-Dawley rats prior to conception and were continued through mating, gestation, and lactation. Female pups, 8 per litter, were fed on their mother's diet for the duration of the study. The pups' sexual maturation occurred at 33, 35, and 70 days of age for the HP, NP, and LP groups, respectively. At 7 weeks of age, duct development in the mammary gland was markedly delayed in the LP group. No significant differences in the extent of ductal development were noted between the HP and NP groups. Morphologic development into terminal end buds, alveolar buds, lobules, and terminal ducts was determined for each diet group at 7 weeks and at sexual maturity plus 3 weeks (SM+3) of age. At 7 weeks, the terminal end bud was the dominant structure in the LP group and was significantly greater in number than in the HP and NP groups. The latter groups were dominated by the alveolar bud structures. At SM+3, the number of terminal end buds decreased, and the alveolar buds increased in the LP group; however, the numbers were still significantly different than in the HP and NP groups. This study indicates that dietary protein affects mammary duct proliferation and morphologic development.

Trends in morbidity and mortality for oesophageal cancer in Linxian County, 1959-1983

Data on morbidity and mortality from oesophageal cancer (EC) over the 25 years from 1959-1983 indicate that this malignancy has been the commonest cause of death in Linxian (LX) county during that period, accounting for 16% of deaths from all causes and 65% of deaths from cancer. Whereas incidence and mortality of EC were high but stable during this period, a decline in mortality has been noted recently in younger age groups, coinciding with an improvement in nutritional standards. Cohort analysis for the period 1879-1954 demonstrates mortality peaks among individuals born late in the last century and early in the present one. It also shows that a decline in mortality appears to have started among natives of the county born during the period 1935-1954.

Simple technique for measurements of pulsed Gaussian-beam spot sizes

A simple technique for in situ measurements of pulsed Gaussian-beam spot sizes is reported. This technique is particularly useful for measurements on highly focused beam spots. It can also be used for absolute calibration of the threshold-energy fluences for pulsed-laser-induced effects. The thresholds for several effects in picosecondlaser-induced phase transformation on silicon-crystal surfaces are calibrated with this technique.

Diurnal fluctuations in methionine-enkephalin levels in the hypothalamus and preoptic area of the male rat: effects of pinealectomy

Methionine-enkephalin (met-enk) levels were measured at 09.30-10.30, 16.30-17.30 and 23.30-00.30 h in the anterior hypothalamus-preoptic area (AHPOA), medial basal hypothalamus (MBH), anterior, intermediate and posterior lobe of the pituitary gland of male rats. Met-enk levels in the AHPOA and MBH fluctuated significantly through a 24-hour period; from low levels at 09.30-10.30 h, met-enk in the AHPOA and MBH rose slowly in the afternoon to reach peak concentrations at 23.30-00.30 h. Pinealectomy appears to depress or shift the normally occurring increments in met-enk levels at 23.30-00.30 h in the AHPOA only. Serum testosterone (T) levels displayed an inverse relationship with the met-enk rhythm; high concentrations during the day were associated with low met-enk levels and as T levels decreased to a nadir at 23.30-00.30 h, the met-enk in the MBH and AHPOA attained peak concentrations. Daily changes in serum T levels were not affected by pinealectomy.