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Biomedical subjects

A Morales

Publications and source records attributed to A Morales.

At least 19 recordsLinked to original sources
PubMed2007

Risk of ischemic stroke and lifetime estrogen exposure.

BACKGROUND: Estrogen loss has been related to higher incidence of stroke in postmenopausal women, but randomized trials have demonstrated an increased risk of stroke in women receiving hormone replacement therapy (HRT). OBJECTIVE: To assess the relationship between exposure to endogenous ovarian hormones and the risk of noncardioembolic ischemic stroke. METHODS: We conducted a multicenter, age-matched, case-control study in postmenopausal women (case: nonembolic ischemic stroke; control: no stroke) comparing duration of ovarian activity or lifetime estrogen exposure, which was defined as age at menarche to age at menopause. Embolic cardiopathy and unreliable gynecologic data were exclusion criteria. Cardiovascular disease risk factors were recorded. The relationships of the principal variables to the risk of stroke were assessed using a conditional logistic regression analysis. RESULTS: There were 430 cases and 905 controls in the study. In the multivariate analysis, hypertension (odds ratio [OR]: 2.73; 95% CI: 2.09 to 3.58; p < 0.0001), diabetes (OR: 3.38; 95% CI: 2.53 to 4.52; p < 0.0001), hyperlipidemia (OR: 1.31; 95% CI: 1.01 to 1.7; p = 0.045), lifespan of ovarian activity <34 years (OR: 1.51; 95% CI: 1.13 to 2.03; p = 0.005), and menarche at <13 years of age (OR 1.49; 95% CI: 1.15 to 1.92; p = 0.002) were independently related to an increased risk of stroke. Obesity (OR: 0.73; 95% CI: 0.56 to 0.95; p = 0.021) was related to a lower risk of stroke. CONCLUSIONS: Longer lifetime exposure to ovarian estrogens may protect against noncardioembolic ischemic stroke. However, a very early age of exposure onset could be disadvantageous.

Age Factors↗
PubMed2006

Influence of harvest bacterial contamination on autologous peripheral blood progenitor cells post-transplant.

Microbiological contamination of manipulated blood products, including hematopoietic progenitors obtained from peripheral blood, is an infrequent but persistent problem in transplant units. The relevance of such contamination in causing patient infection has been reported as insignificant, but the effect on the post-transplant course has not been well documented. We studied the incidence of bacterial contamination in autologous peripheral blood progenitor cell transplants in two of the bench processing steps, as well as the repercussions in the post-transplant course affecting incidence of infections, transfusion requirements and time to engraftment. A total of 365 aphereses performed on 152 patients were cryopreserved in 617 bags. In 31 of these bags (5.0%), bacterial cultures were positive for Coagulase-negative Staphylococcus (31.1%), S. epidermidis (21.9%), Corynebacterium sp. (6.3%), S. warneri (6.3%), Stenotrophomonas maltophilia (6.3%), Streptococcus sp. (9.4%), Viridans group Streptococcus (3.1%) and more than one bacteria (Coagulase-negative Staphylococcus plus Corynebacterium) (15.6%). Half of the bags were contaminated at the time of freezing and the others at the time of thawing. The 31 contaminated bags were infused into 17 patients. In five of these the same contaminating bacteria was found. No difference between the two groups of patients (contaminated and non-contaminated) was found on the day the fever started, length of fever, blood transfusion requirements and engraftment, but length of hospitalization was significantly greater in patients receiving contaminated transplants.

Bacteria↗
PubMed2006

The effect of feeding low-phytate barley-soybean meal diets differing in protein content to growing pigs on the excretion of phosphorus and nitrogen.

An experiment was conducted with growing pigs to determine the excretion of P and N in 4 barley-based diets formulated to contain 18 or 15% CP by using a normal barley (NB) or a low-phytate barley (LPB). The NB contained 0.31% total P and 0.19% phytate P; the LPB contained 0.32% total P and 0.01% phytate P. The diets were supplemented, when so required, with lysine, methionine, threonine, and tryptophan to meet their apparent ileal digestible supplies according to the NRC (1998). The diets containing NB were supplemented with inorganic P to meet the NRC (1998) recommendation for available P (0.23%). The diets containing LPB were not supplemented with inorganic P because these contained sufficient available P (0.27%). Eight barrows with an average BW of 20.9 kg were assigned to the 4 dietary treatments according to a repeated 4 x 4 Latin square design. The diets were fed at a rate of 2.5 times the ME requirement for maintenance. The barrows were fed twice daily, at 0800 and 1500, equal amounts each meal. Water was added to the feed at a ratio of 2.5:1. Each experimental period consisted of a 7-d adaptation period followed by a 5-d collection of feces and urine. The substitution of NB with LPB decreased (P < 0.001) the total P excretion by 38 and 43% for the 18 and 15% CP diets, respectively. Reducing the CP content from 18 to 15% decreased (P < 0.001) the N excretion by 29 and 32% for the NB and LPB diets, respectively. With the reduction in CP content, there was a decrease (P < 0.001) in the amount of N retained. The N:P ratio in manure of pigs fed the LPB diets was greater (P < 0.001) than from pigs fed the NB diets. These data indicate that P and N excretion can be greatly reduced by substitution of NB by LPB, and also by the reduction of the CP content, in diets for growing pigs.

Animal Feed↗
PubMed2006

Wannier-stark ladders in one-dimensional elastic systems.

The optical analogues of Bloch oscillations and their associated Wannier-Stark ladders have been recently analyzed. In this Letter we propose an elastic realization of these ladders, employing for this purpose the torsional vibrations of specially designed one-dimensional elastic systems. We have measured, for the first time, the ladder wave amplitudes, which are not directly accessible either in the quantum-mechanical or optical cases. The wave amplitudes are spatially localized and coincide rather well with theoretically predicted amplitudes. The rods we analyze can be used to localize different frequencies in different parts of the elastic systems and vice versa.

Journal Article↗
PubMed2006

Pharmacological inhibition or small interfering RNA targeting acid ceramidase sensitizes hepatoma cells to chemotherapy and reduces tumor growth in vivo.

Ceramidases (CDases) play a key role in cancer therapy through enhanced conversion of ceramide into sphingosine 1-phosphate (S1P), but their involvement in hepatocarcinogenesis is unknown. Here, we report that daunorubicin (DNR) activated acid CDase post-transcriptionally in established human (HepG2 cells) or mouse (Hepa1c1c7) hepatoma cell lines as well as in primary cells from murine liver tumors, but not in cultured mouse hepatocytes. Acid CDase silencing by small interfering RNA (siRNA) or pharmacological inhibition with N-oleoylethanolamine (NOE) enhanced the ceramide to S1P balance compared to DNR alone, sensitizing hepatoma cells (HepG2, Hep-3B, SK-Hep and Hepa1c1c7) to DNR-induced cell death. DNR plus NOE or acid CDase siRNA-induced cell death was preceded by ultrastructural changes in mitochondria, stimulation of reactive oxygen species generation, release of Smac/DIABLO and cytochrome c and caspase-3 activation. In addition, in vivo siRNA treatment targeting acid CDase reduced tumor growth in liver tumor xenografts of HepG2 cells and enhanced DNR therapy. Thus, acid CDase promotes hepatocarcinogenesis and its antagonism may be a promising strategy in the treatment of liver cancer.

Animals↗
PubMed2006

New software for computer-assisted dental-data matching in Disaster Victim Identification and long-term missing persons investigations: "DAVID Web".

In 1997 an internally supported but unfunded pilot project at the Victorian Institute of Forensic Medicine (VIFM) Australia led to the development of a computer system which closely mimicked Interpol paperwork for the storage, later retrieval and tentative matching of the many AM and PM dental records that are often needed for rapid Disaster Victim Identification. The program was called "DAVID" (Disaster And Victim IDentification). It combined the skills of the VIFM Information Technology systems manager (VW), an experienced odontologist (JGC) and an expert database designer (JC); all current authors on this paper. Students did much of the writing of software to prescription from Monash University. The student group involved won an Australian Information Industry Award in recognition of the contribution the new software could have made to the DVI process. Unfortunately, the potential of the software was never realized because paradoxically the federal nature of Australia frequently thwarts uniformity of systems across the entire country. As a consequence, the final development of DAVID never took place. Given the recent problems encountered post-tsunami by the odontologists who were obliged to use the Plass Data system (Plass Data Software, Holbaek, Denmark) and with the impending risks imposed upon Victoria by the decision to host the Commonwealth Games in Melbourne during March 2006, funding was sought and obtained from the state government to update counter disaster preparedness at the VIFM. Some of these funds have been made available to upgrade and complete the DAVID project. In the wake of discussions between leading expert odontologists from around the world held in Geneva during July 2003 at the invitation of the International Committee of the Red Cross significant alterations to the initial design parameters of DAVID were proposed. This was part of broader discussions directed towards developing instruments which could be used by the ICRC's "The Missing" project that seeks to identify the victims of civil unrest and other atrocities. The most significant of these recommendations was that the next version of DAVID should be web-based allowing it to be used anywhere in the world and on any computer platform. The original intention that the software should be made available as freeware was strongly reiterated and endorsed. During 2005 these recommendations have been realized. This paper will describe the design parameters of the new software "DAVID web" and compare its features and performance with alternative packages.

Database Management Systems↗
PubMed2006

Clinical experience with the new long-acting injectable testosterone undecanoate. Report on the educational symposium on the occasion of the 5th World Congress on the Aging Male, 9-12 February 2006, Salzburg, Austria.

This symposium report summarizes first extensive clinical findings with injectable testosterone undecanoate (Nebido) in hypogonadal patients showing clinical symptoms of androgen deficiency with or without erectile dysfunction (ED). This new testosterone formulation (1000 mg testosterone undecanoate in 4 ml castor oil) possesses nearly ideal long-term kinetics, i.e. sustained close mimicking of eugonadal testosterone serum levels without supra- or sub-physiological serum concentrations. The generally accepted administration scheme recommends the second injection 6 weeks after the first one followed by further injections every 12 weeks. Applying this regimen, administration intervals are drastically reduced in comparison to conventional i.m. testosterone preparations (e.g. about 16 injections of testosterone enanthate vs. 4-5 injections of testosterone undecanoate per year). Depending on the testosterone serum levels, individualized therapy is possible by shortening (every 10 weeks) or prolonging (every 14 weeks) the injection intervals. In hypogonadal patients with ED 58% respond to testosterone undecanoate alone. Best results are seen in diabetic hypogonadal patients. The regimen of injectable testosterone undecanoate administration ideally fits recommendations regarding pharmacokinetics, efficacy and safety monitoring.

Aged↗
PubMed2005

BW284c51 blocks nicotinic acetylcholine receptors transplanted to Xenopus oocytes.

We have studied the effects of BW284c51 on the function of Torpedo nicotinic acetylcholine (Ach) receptors (nAchRs) transplanted to Xenopus laevis oocytes. BW284c51 reversible inhibited Ach-elicited currents (IAch) in a concentration-dependent manner, increased IAch desensitisation and changed the Ach concentration-dependence of the IAch from a two-site to a single-site Hill equation, without affecting the EC50. These effects were only present at hyperpolarising potentials, suggesting that nAchR blockade by BW284c51 is non-competitive and likely due to an open channel block as the principal mechanism.

Animals↗
PubMed2005

New limit on the neutrinoless betabeta decay of 130Te.

We report the present results of CUORICINO, a search for neutrinoless double-beta (0nu betabeta) decay of 130Te. The detector is an array of 62 TeO2 bolometers with a total active mass of 40.7 kg. The array is cooled by a dilution refrigerator shielded from environmental radioactivity and energetic neutrons, operated at approximately 8 mK in the Gran Sasso Underground Laboratory. No evidence for (0nu betabeta) decay was found and a new lower limit, T(1/2)(0nu) > or = 1.8 x 10(24) yr (90% C.L.) is set, corresponding to [m(nu)] < or = 0.2 to 1.1 eV, depending on the theoretical nuclear matrix elements used in the analysis.

Journal Article↗
PubMed2005

First results from the CERN axion solar telescope.

Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses.

Journal Article↗
PubMed2005

The current status of therapy for symptomatic late-onset hypogonadism with transdermal testosterone gel.

For over 50 years, testosterone therapy has been used for the treatment of hypogonadism. In recent years, there has been an increase in the use of testosterone therapy for men with late-onset hypogonadism, as more convenient and effective modes of application are developed. Testosterone therapy in these men can significantly improve their sense of well-being, and lead to increases in muscle and bone mass, upper body strength, virility and libido [Gruenewald, Matsumoto. J Am Geriatr Soc 2003;51:101; Morales. Aging Male 2004; in press]. However, ensuring that optimal testosterone therapy is achieved in men with hypogonadism remains challenging. Oral delivery of unmodified testosterone is not possible, due to rapid first-pass metabolism and its short half-life. Therefore, different derivatives and formulations of testosterone have been developed to enhance potency, prolong duration of action or improve bioavailability. In addition, several different routes of administration have now been evaluated, including intramuscular injections, oral formulations, transdermal patches, transbuccal systems and transdermal testosterone gel. Despite the broad range of testosterone therapy on offer, each form has its benefits and limitations, and some will suit one patient more than another. An important concern among clinicians is that testosterone therapy may cause or promote prostate cancer. While current evidence supports the safety of testosterone therapy, androgens are growth factors for pre-existing prostate cancer. Therefore, before therapy is initiated, careful digital rectal examination and determination of prostate-specific antigen (PSA) in serum should be performed, in order to exclude evident or suspected prostate cancer. The first 3-6 months after initiating testosterone therapy is the most critical time for monitoring effects on the prostate. Therefore, it is important to monitor PSA levels every 3 months for the first year of treatment; thereafter, regular monitoring (mostly for prostate safety but also for cardiovascular and haematological safety) during therapy is mandatory.

Administration, Cutaneous↗
PubMed2005

The treatment of patients with symptomatic common bile duct stenosis secondary to chronic pancreatitis using partially covered metal stents: a pilot study.

BACKGROUND AND STUDY AIMS: Although surgery remains the gold standard for the treatment of symptomatic common bile duct stenosis associated with chronic pancreatitis, plastic and self-expandable open-mesh stents have been proposed as alternative treatments. These may dysfunction, however, mainly due to stent occlusion by clogging or by hyperplasia of inflammatory tissue. The aim of this study was to evaluate the safety and long-term results of using partially covered metal stents in this setting. PATIENTS AND METHODS: A total of 14 patients (12 men, 2 women; mean age 50 +/- 3 years) underwent partially covered metal stent insertion for common bile duct stenosis secondary to chronic pancreatitis (12 alcohol-related, two idiopathic). They had all been treated previously with plastic prostheses. RESULTS: Either a 40-mm (n = 13) or a 60-mm (n = 1) partially covered metal stent was placed, depending on the length of the common bile duct stenosis and the level of the cystic duct bifurcation. Stent placement was successful, with resolution of cholangitis and improvement in cholestasis, in all patients. During the median follow-up period of 22 months (range 12 - 33 months) seven patients developed dysfunction of the stent and required re-treatment. At 12, 24, and 30 months, the stent patency rates were 100 %, 40 %, and 37.5 % respectively. CONCLUSIONS: While partially covered metal stenting is safe and effective for the initial treatment of chronic pancreatitis-associated common bile duct stenosis and shows promising short-term results, long-term data show that dysfunction occurs in 50 % of cases. In light of the continued interest in nonsurgical treatment of this condition, further research is warranted to investigate new stent designs with improved long-term patency.

Adult↗
PubMed2005

Locally periodic Timoshenko rod: experiment and theory.

The flexural vibrations of a locally periodic rod, which consists of N unit cells, are discussed both from the experimental and theoretical points of view. Timoshenko's beam theory and the transfer matrix method are used to calculate the normal-mode frequencies and amplitudes. The theoretical values are then compared with the experimental ones, which are obtained using an electromagnetic acoustic transducer (EMAT). Good agreement between the numerical results and the experimental measurements is obtained. It is shown that as N grows, a band spectrum emerges.

Acoustics↗
PubMed2005

Monitoring androgen replacement therapy: testosterone and prostate safety.

The aging of the world population has brought to the forefront of medical practice the diagnosis and treatment of hypogonadism in adult men. There is an increasing interest on the use of testosterone (T) and other androgens to manage men with clinical and biochemical evidence of hypogonadism. Although treatment with T has been used for 70 yr and it is, generally, safe and effective, there are a number of safety issues--ranging from cardiovascular and lipid alterations to hematological changes--that the physician needs to be aware of. Unquestionably, prostate safety constitutes the most important one. No evidence exists that appropriate androgen administration with knowledgeable monitoring carries significant or potentially serious adverse effects on the prostate gland. Men with symptomatic lower urinary obstruction need to be assessed carefully prior to androgen administration. The suspicion of prostate cancer is an absolute contraindication for T use. Recommendations are available for the judicious and safe use of T in aging men.

Aged↗
PubMed2004

Andropause (or symptomatic late-onset hypogonadism): facts, fiction and controversies.

The existence of the so-called 'andropause' is an irrefutable fact, although the terms 'SLOH' (symptomatic late-onset hypogonadism) or 'symptomatic ADAM' (androgen deficiency of the aging male) are more accurate. The term 'andropause' is, in most cases, inappropriate, except when the gonads cease functioning. Testosterone production decreases as a function of age, but this decrease is not universal. Several clinical manifestations are associated with hypogonadism, but these are not solely attributable to hypogonadism. Other hormones (i.e. dehydroepiandrosterone, growth hormone, thyroxine and melatonin) also decrease with age. Such multi-hormone alterations are closely inter-related and may influence 'andropause-related' symptoms. Many patients with SLOH, although by no means all, respond well to testosterone therapy. Although testosterone therapy can induce adverse effects, these can be largely minimized by proper monitoring by a knowledgeable clinician. Extrapolation of the effects of estrogens + progesterone in menopausal women to the use of testosterone in hypogonadal men is mythical, and more research on the effect of exogenous sex steroids in aging men and women is needed. However, to restrict the prescription of such hormones until all issues have been fully addressed is impossible. Indeed, the discourse on SLOH would benefit considerably from more science and less speculation.

Aging↗
PubMed2004

Quantitative assessment of a new preparatory tool for board certification in urology.

OBJECTIVE: To analyse the performance of candidates in a Canadian national mock-examination for final-year urology residents with respect to North American speciality examinations in urology. METHODS: In 1997 the Queen's Urology Examination Skills Training Program (QUEST) was established as an annual national mock examination for final-year Canadian urology residents. It consists of a short answer question component and an objective structured clinical examination. During the 5-year period (1997-2001), 91 final-year residents from all 11 Canadian urology residency-training programmes participated in QUEST and the Royal College of Physicians and Surgeons of Canada certifying examinations (RCPSCE); 43 (47%) of candidates also attempted the American Board of Urology part 1 qualifying examinations (ABU 1). Performance on QUEST was correlated with the RCPSCE and ABU 1 in a blinded fashion after submitting QUEST scores to governing bodies. Thresholds were determined to help to predict a candidate's performance on the RCPSCE and ABU 1, based on QUEST scores. RESULTS: There was a moderately close correlation between overall QUEST and RCPSCE performance (r = 0.68, P < 0.001) and a moderate correlation between overall QUEST and ABU 1 performance (r = 0.42, P = 0.005). For the following QUEST scores, the probability of success on the RCPSCE was: < 65%, 67% pass; 66-75%, 80% pass; > 75%, 100% pass (P = 0.002). For ABU 1, QUEST overall score of 80% gave a 69% probability of scoring > or = 70% on ABU 1 (P = 0.003). CONCLUSIONS: QUEST is a moderate predictor of performance on speciality examinations in urology. We consider that the time, effort and expense to maintain QUEST are justified.

Education, Medical, Undergraduate↗
PubMed2003

Second mobilization of peripheral blood progenitor cells in patients with poor first mobilization.

The aim of this study was to analyse the efficacy of 2 second mobilization (MB) protocols in 2 groups of patients who failed to obtain enough peripheral blood progenitor cells (PBPC) in the first MB. In 1 group (8 patients), 10 microg/kg of G-CSF was administered, and in the other group (8 patients), a double dosage (10 microg/kg twice a day) was administered. Both groups of patients received Cyclophosphamide (1.5 g/kg) 10 days before the apheresis. No difference was found among both groups of patients in diagnosis, previous chemotherapy, and time elapsed after the first MB. Administration of higher doses of G-CSF decreased the number of apheresis needed in the second MB to complete 2 x 10(6)/kg of CD34+ cells. It also increased the number of patients who achieved sufficient CD34+, namely, 75% versus 50%.

Blood Cells↗