Ten-Year Review of Tracheostomy Techniques and Related Complications.

Background: Tracheostomy is a frequently performed procedure that allows for definitive airway access in critically ill patients. Complications associated with tracheostomy have been well documented in the literature. This study aims to examine if different tracheostomy techniques were associated with specific complications.

Hydrogen sulfide and cerebral microvascular tone in newborn pigs.

Hydrogen sulfide (H2S) is a gaseous signaling molecule that appears to be involved in numerous biological processes, including regulation of blood pressure and vascular tone. The present study is designed to address the hypothesis that H2S is a functionally significant, endogenous dilator in the newborn cerebrovascular circulation. In vivo experiments were conducted using newborn pigs with surgically implanted, closed, cranial windows.

Glutamate regulates Ca2+ signals in smooth muscle cells of newborn piglet brain slice arterioles through astrocyte- and heme oxygenase-dependent mechanisms.

Glutamate is the principal cerebral excitatory neurotransmitter and dilates cerebral arterioles to match blood flow to neural activity. Arterial contractility is regulated by local and global Ca(2+) signals that occur in smooth muscle cells, but modulation of these signals by glutamate is poorly understood. Here, using high-speed confocal imaging, we measured the Ca(2+) signals that occur in arteriole smooth muscle cells of newborn piglet tangential brain slices, studied signal regulation by glutamate, and investigated the physiological function of heme oxygenase (HO) and carbon monoxide (CO) in these responses.

Astrocyte-derived CO is a diffusible messenger that mediates glutamate-induced cerebral arteriolar dilation by activating smooth muscle Cell KCa channels.

Astrocyte signals can modulate arteriolar tone, contributing to regulation of cerebral blood flow, but specific intercellular communication mechanisms are unclear. Here we used isolated cerebral arteriole myocytes, astrocytes, and brain slices to investigate whether carbon monoxide (CO) generated by the enzyme heme oxygenase (HO) acts as an astrocyte-to-myocyte gasotransmitter in the brain. Glutamate stimulated CO production by astrocytes with intact HO-2, but not those genetically deficient in HO-2.

Heme is a carbon monoxide receptor for large-conductance Ca2+-activated K+ channels.

Carbon monoxide (CO) is an endogenous paracrine and autocrine gaseous messenger that regulates physiological functions in a wide variety of tissues. CO induces vasodilation by activating arterial smooth muscle large-conductance Ca2+-activated potassium (BK(Ca)) channels. However, the mechanism by which CO activates BK(Ca) channels remains unclear.

A newly discovered mycobacterial pathogen isolated from laboratory colonies of Xenopus species with lethal infections produces a novel form of mycolactone, the Mycobacterium ulcerans macrolide toxin.

Mycobacterium ulcerans, the causative agent of Buruli ulcer, produces a macrolide toxin, mycolactone A/B, which is thought to play a major role in virulence. A disease similar to Buruli ulcer recently appeared in United States frog colonies following importation of the West African frog, Xenopus tropicalis. The taxonomic position of the frog pathogen has not been fully elucidated, but this organism, tentatively designated Mycobacterium liflandii, is closely related to M.

Optimized sample-processing time and peptide recovery for the mass spectrometric analysis of protein digests.

Proteomics requires an optimized level of sample-processing, including a minimal sample-processing time and an optimal peptide recovery from protein digests, in order to maximize the percentage sequence coverage and to improve the accuracy of protein identification. The conventional methods of protein characterization from one-dimensional or two-dimensional gels include the destaining of an excised gel piece, followed by an overnight in-gel enzyme digestion. The aims of this study were to determine whether: (1) stained gels can be used without any destaining for trypsin digestion and mass spectrometry (MS); (2) tryptic peptides can be recovered from a matrix-assisted laser desorption/ionization (MALDI) target plate for a subsequent analysis with liquid chromatography (LC) coupled to an electrospray ionization (ESI) quadrupole ion trap MS; and (3) an overnight in-gel digestion is necessary for protein characterization with MS.

Quantitative analysis of [Dmt(1)]DALDA in ovine plasma by capillary liquid chromatography-nanospray ion-trap mass spectrometry.

The synthetic opioid peptide analog Dmt-D-Arg-Phe-Lys-NH(2) ([Dmt(1)]DALDA; [Dmt= 2',6'-dimethyltyrosine) is a highly potent and selective mu opioid-receptor agonist. A very sensitive and robust capillary liquid chromatography/nanospray ion-trap (IT) mass spectrometry method has been developed to quantify [Dmt(1)]DALDA in ovine plasma, using deuterated [Dmt(1)]DALDA as the internal standard. The standard MS/MS spectra of d(0)- and d(5)-[Dmt(1)]DALDA were obtained, and the collision energy was experimentally optimized to 25%.

Proteome of monocytes primed with lipopolysaccharide: analysis of the abundant proteins.

We performed a proteomic analysis of monocytes primed by lipopolysaccharide (LPS) in vitro, using two-dimensional gels stained with Coomassie blue. We found 16 proteins of approximately 500 detected that either increased or decreased in abundance as a result of priming by LPS (14 with P View Article and Find Full Text PDF

Downregulation of a unique photoreceptor protein correlates with improper outer segment assembly.

A unique photoreceptor protein has been characterized. This protein, termed XAP-1 antigen, is expressed by photoreceptors exclusively under conditions in which the outer segment membranes are properly assembled. When the retinal pigment epithelium is adherent to the underlying neural retina, the XAP-1 antigen is localized to the plasma membrane that surrounds the inner and outer segments in the areas juxtaposed to the subretinal space.

Matrix-assisted laser desorption/ionization mass spectrometric quantification of the mu opioid receptor agonist DAMGO in ovine plasma.

The synthetic opioid peptide analog Tyr-D-Ala-Gly-N-methyl-Phe-Gly-ol (DAMGO), which is a mu opioid receptor-selective agonist, was quantified in ovine plasma samples with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), using delayed extraction and a reflectron. The internal standard was pentadeuterated DAMGO. Timed-ion selection was used to select the precursor ion.

Ovarian hyperstimulation augments adrenal dehydroepiandrosterone sulfate secretion.

Objective: To determine if factor(s) secreted by the ovaries during hyperstimulation potentiate basal and ACTH-stimulated adrenal androgen secretion.

Design: Retrospective and prospective and prospective clinical study.

Setting: University tertiary care center infertility clinic.

Delivery of dehydroepiandrosterone to premenopausal women: effects of micronization and nonoral administration.

Objectives: This single-dose study compares three dehydroepiandrosterone delivery methods (oral crystalline steroid, micronized steroid, and vaginal administration) to ascertain whether physiologic levels of circulating dehydroepiandrosterone and dehydroepiandrosterone sulfate can be obtained while increases in testosterone are minimized.

Study Design: Two randomized, double-blind, placebo-controlled single-dose comparisons were made. For oral micronized versus crystalline dehydroepiandrosterone 300 mg doses of micronized or crystalline dehydroepiandrosterone were administered, followed by 6 hours of blood sampling (n=7).

Postmenopausal steroid replacement with micronized dehydroepiandrosterone: preliminary oral bioavailability and dose proportionality studies.

Objectives: Because dehydroepiandrosterone may protect against neoplasia, osteoporosis, and cardiac disease, we investigated the bioavailability of oral micronized dehydroepiandrosterone, anticipating its adjunctive use in postmenopausal steroid replacement.

Study Design: Eight postmenopausal women randomly received either a placebo or 150 or 300 mg of oral micronized dehydroepiandrosterone in a lipid matrix. Serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, testosterone, and estradiol were measured periodically over the 12 hours after each dose.

Rising human chorionic somatomammotropin predicts ectopic pregnancy rupture following methotrexate chemotherapy.

In the medical management of ectopic pregnancy, human chorionic somatomammotropin (hCS) proved to be a more sensitive indicator of continued trophoblastic activity than either beta-human chorionic gonadotropin (beta-hCG) or progesterone (P). In the authors' series of 21 women treated with methotrexate for ectopic pregnancies, only two ruptured. In both cases, hCS levels continued to rise during and after methotrexate treatment.

Additional binding sites for delta 5-androstenediol and estradiol in serum.

A graphic method called close-pair-analysis is described for determining the high affinity binding parameters in a complex system. Assumptions are that the nonspecific binding is accurately measured, and that there are two specific binding classes in which the affinities (Ka) are a factor of 5 or greater apart. Using this method and equilibrium dialysis data of delta 5-Adiol and E2 binding in serum, an apparently new binding site class was found.

Deprivation and repletion of androgen in vivo modifies triacylglycerol synthesis by rat hepatocytes.

Given the same quantity of fatty acid, livers from male rats esterify less fatty acid and secrete less triacylglycerol in very-low-density lipoprotein than do livers from female animals. To elucidate the role of testosterone in maintenance of this male pattern, conversion of [1-14C]oleic acid into triacylglycerol was assessed in vitro by rat hepatocytes (male) following gonadectomy and replacement with testosterone. Following castration, incorporation of fatty acid into triacylglycerol was increased.

Nonsteroidal substances that affect serum free testosterone.

Several steroid hormones affect free testosterone (FT) levels in blood by competing with testosterone for binding sites on testosterone-binding globulin (TeBG). However, the effect of endogenous nonsteroidal substances in serum has not been reported. Some of these potential modifiers of FT were studied using equilibrium dialysis.

A theoretically sound and practicable equilibrium dialysis method for measuring percentage of free testosterone.

Free testosterone measured in serum equilibrated in vitro is considered a good index of biologically available testosterone even though a large part of free testosterone in vivo is derived locally from rapid dissociation of testosterone bound to albumin. The most accurate method for measuring free testosterone, however, is unsettled. The classical method--equilibrium dialysis--has been questioned because of the dilution of serum that it entails and the previous inability to achieve identical results with diluted and undiluted serum.

Androgen parameters and their correlation with body weight in one hundred thirty-eight women thought to have hyperandrogenism.

The first objective of this study was to determine which plasma androgen assay or combination of assays would be the most useful in documenting hyperandrogenism in women with hirsutism, acne, oligomenorrhea, or unexplained infertility. Plasma levels of androstenedione (A), total testosterone (T), and dehydroepiandrosterone sulfate (DHEAS) were measured and free T (FTc) was calculated from the measured total T and T-estradiol-binding globulin binding capacity (TeBG-BC) in 138 consecutive women referred to our clinic for hirsutism, acne, oligomenorrhea, and/or unexplained infertility. FTc was elevated in 82% and was most frequently elevated parameter.