Serum concentrations of luteinizing hormone, growth hormone, and cortisol in gilts treated with N-methyl-D,L-aspartate during the estrous cycle or after ovariectomy

The objective of this experiment was to determine the effects of n-methyl-d,l-aspartate (NMA), an agonist of the neurotransmitter glutamate, on circulating concentrations of LH, GH, and cortisol in gilts treated during the luteal (n = 4) or follicular (n = 4) phase of the estrous cycle, or after ovariectomy (n = 4). Blood was sampled every 15 min for 10 h on each of two consecutive days. On the 1st d, two gilts from each group received i.v. injections of NMA (10 mg/kg BW) at h 4 and 6, and the remaining gilts received .9% saline (vehicle). The following day, gilts that had received NMA on the 1st d received vehicle, and gilts that had received vehicle on d 1 received NMA. All gilts received an i.v. challenge of GnRH (.1 microg/kg BW) at h 8 on each day. The NMA treatment increased (P < .01) LH pulse frequency in luteal-phase gilts by 125%. In contrast, NMA decreased (P < .05) mean concentrations of LH by 48% and suppressed (P < .01) LH pulse frequency by 33% in ovariectomized gilts. No characteristics of LH secretion were affected (P > .05) by NMA in follicular phase gilts. Serum LH concentrations for the 2-h period following GnRH were lower (P < .05) in follicular-phase gilts than in ovariectomized gilts and were 1.15 +/- .09 (mean +/- SE), .81 +/- .05, and .51 +/- .17 ng/mL for ovariectomized, luteal-phase, and follicular-phase gilts, respectively. Treatment with NMA increased circulating concentrations of GH by 334% (P < .01) and cortisol by 77% (P < .03) in all gilts. We suggest that the effects of NMA on LH release in gilts depend on the circulating steroidal milieu. In contrast, NMA evokes secretion of GH and cortisol irrespective of the reproductive status of treated gilts.     

Automobile accidents in patients with sleep apnea syndrome. An epidemiological and mechanistic study

AIM: To compare the pregnancy outcome, in particular gestational age and birth weight in women with systemic lupus erythematosus (SLE) diagnosed before and after pregnancy, and to review data on presence or absence of the antiphospholipid (aPL) antibody and flares of disease activity. METHOD: Case histories were reviewed of women with a diagnosis of SLE and an obstetric event attending Monash Medical Centre (MMC) over an eight year period (1988-96). Fifty-four pregnancies in 28 women were studied, with 44 occurring after the diagnosis of SLE (Group 1) and ten prior to the diagnosis of SLE (Group 2). RESULTS: In Group 1 there were 25 live births (63%) with 16 full term and nine premature deliveries, 12 spontaneous abortions, three foetal deaths in utero and four elective terminations. In Group 2 there were seven live births (70%), two spontaneous abortions and one foetal death in utero. The mean gestational age of live births was 35.8 weeks and 39.2 weeks respectively (p < 0.001). The mean birth weight of live births was 2448 g and 3030 g respectively (p < 0.023). a PL antibodies were positive in eight of 26 women tested with three live births and were negative in 18 of 26 women with 12 live births. Flares of disease activity occurred in 17 of 28 pregnancies. CONCLUSION: Pregnancy in women with a predisposition to SLE have a high risk of an adverse outcome. Clinical disease confers an additional risk. The mean gestational age and birth weight were significantly less in women with established disease. Mild flares in disease activity resulted in a favourable outcome while renal flares had a worse outcome.     

Treatment of sleep apnea-hypoapnea syndrome

Two patients with chronic myelogenous leukemia are described in whom thrombotic thrombocytopenic purpura (TTP) developed following treatment by interferon-alpha. In one of the patients, a lymphoblastic transformation was diagnosed concomitantly. Prompt institution of plasmapheresis, steroids and vincristine resulted in complete resolution. In the hitherto reported case of TTP complicating interferon-alpha treated chronic myelogenous leukemia, the course was fatal.     

Central and peripheral administration of kisspeptin activates gonadotropin but not somatotropin secretion in prepubertal gilts

It is well established that kisspeptin signaling is necessary for the onset of puberty in laboratory animals. However, the role that kisspeptin may have in regulating puberty in large domestic animals is unknown. We tested the hypothesis that either central or peripheral infusion of kisspeptin would stimulate gonadotropin and GH secretion in prepubertal gilts. In experiment 1, prepubertal gilts were fitted with i.c.v. cannula and indwelling jugular catheters. Animals were randomly assigned to receive 0, 10, or 100 microg kisspeptin in saline. In experiment 2, prepubertal gilts, fitted with indwelling jugular catheters, randomly received 0, 1, 2.5, or 5 mg kisspeptin in saline intravenously. Serial blood samples were collected every 15 min for 3 h before and 5 h after infusions, and serum concentrations of LH, FSH, and GH were determined. Mean concentrations of LH and FSH remained at basal levels for control animals but were increased (P<0.001) for animals receiving i.c.v. infusion of kisspeptin. Area under the LH and FSH curves following i.c.v. infusion of kisspeptin increased (P<0.001) in a dose-dependent manner. Concentrations of GH were unaffected by i.c.v. treatment. Peripheral administration of kisspeptin increased (P<0.05) serum concentrations of LH but not FSH or GH. Thus, kisspeptin can activate gonadotropic but not somatotropic hormone secretion in prepubertal gilts. The present data support the concept that kisspeptin plays a role in the mechanism involved in initiating puberty in swine.     

Shallow donors with high n-type electrical conductivity in homoepitaxial deuterated boron-doped diamond layers

Diamond is a unique semiconductor for the fabrication of electronic and opto-electronic devices because of its exceptional physical and chemical properties. However, a serious obstacle to the realization of diamond-based devices is the lack of n-type diamond with satisfactory electrical properties. Here we show that high-conductivity n-type diamond can be achieved by deuteration of particularly selected homo-epitaxially grown (100) boron-doped diamond layers. Deuterium diffusion through the entire boron-doped layer leads to the passivation of the boron acceptors and to the conversion from highly p-type to n-type conductivity due to the formation of shallow donors with ionization energy of 0.23 eV. Electrical conductivities as high as 2omega(-1) x cm(-1) with electron mobilities of the order of a few hundred cm2 x V(-1) x s(-1) are measured at 300 K for samples with electron concentrations of several 10(16) x cm(-3). The formation and break-up of deuterium-related complexes, due to some excess deuterium in the deuterated layer, seem to be responsible for the reversible p- to n-type conversion. To the best of our knowledge, this is the first time such an effect has been observed in an elemental semiconductor.     

如何看待控制器的操作系统

控制器提供商和系统集成商纷纷加入了私有性与开放性问题的讨论,讨论的内容包括Microsoft的Windows、Linux以及接口和编程工具的重要性。     

Reducing the wrapping effect

When solving ODEs by interval methods, the main difficulty is reducing the wrapping effect. Various solutions have been put forward, all of which are applicable for narrow initial intervals or to particular classes of equations only. This paper describes an algorithm which, instead of intervals, uses a larger family of sets. The algorithm exhibits a very small wrapping effect and applies to any type of equation and initial region. For the time being it handles only two-dimensional equations.     

On the Hankel singular values of linear continuous and sampled-data multivariable systems

This paper considers the Hankel singular values of the sample-data systems obtained from continuous-time models via standard sampling techniques. It is shown that the Hankel singular values of the sampled-data system recover the Hankel singular values of the continuous-time system as the sampling period approaches zero. A state space proof of this result is given.     

Creating a Natural Vascular Scaffold by Photochemical Treatment of the Extracellular Matrix for Vascular Applications

The development of bioscaffolds for cardiovascular medical applications, such as peripheral artery disease (PAD), remains to be a challenge for tissue engineering. PAD is an increasingly common and serious cardiovascular illness characterized by progressive atherosclerotic stenosis, resulting in decreased blood perfusion to the lower extremities. Percutaneous transluminal angioplasty and stent placement are routinely performed on these patients with suboptimal outcomes. Natural Vascular Scaffolding (NVS) is a novel treatment in the development for PAD, which offers an alternative to stenting by building on the natural structural constituents in the extracellular matrix (ECM) of the blood vessel wall. During NVS treatment, blood vessels are exposed to a photoactivatable small molecule (10-8-10 Dimer) delivered locally to the vessel wall via an angioplasty balloon. When activated with 450 nm wavelength light, this therapy induces the formation of covalent protein–protein crosslinks of the ECM proteins by a photochemical mechanism, creating a natural scaffold. This therapy has the potential to reduce the need for stent placement by maintaining a larger diameter post-angioplasty and minimizing elastic recoil. Experiments were conducted to elucidate the mechanism of action of NVS, including the molecular mechanism of light activation and the impact of NVS on the ECM.