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Biomedical subjects

A Albert

Publications and source records attributed to A Albert.

At least 109 records · Page 6Linked to original sources
PubMed1998

[Urinary obstruction in fetal rabbits. An experimental model].

An original model of urethral ligation on 23 gestational-day fetal rabbits is described, that can be applied in studies of both urinary obstruction and oligohydramnios. The surgical technique is detailed and subsequent urinary obstruction is assessed, as well as the lung weight. In conclusion, this is an easy, mildly aggressive, inexpensive and fast model that can be used to investigate the pathophysiology of urinary obstruction and that of oligohydramnios.

Animals↗
PubMed1997

Acute changes in serum calcium and parathyroid hormone circulating levels induced by the oral intake of five currently available calcium salts in healthy male volunteers.

Several calcium supplements are currently available and many of them are marketed without proper comparison of the bioavailability of the actual preparations. The aim of the present trial was to evaluate and compare the acute changes in serum calcium (Ca) and parathyroid hormone (PTH) levels following the oral administration of a vehicle and of five calcium salts currently prescribed in Western Europe. No significant changes in serum Ca or PTH levels were observed after administration of the vehicle. All calcium salts induced significant increases in serum Ca and decreases in serum PTH compared to baseline values. Comparison of the six response curves revealed a significantly greater increase in serum Ca and a greater decrease in serum PTH after each of the calcium salts than observed after the vehicle. However, no statistically significant differences were observed between the different calcium salts for serum Ca increments. The decrease in serum PTH observed after administration of an ossein-hydroxyapatite complex was significantly less important than after the four other calcium salts, even if statistically different than after vehicle. When assessing the area under the curve (AUC) of PTH values, we observed that calcium carbonate and citrate induce a significantly greater decrease in serum PTH than the other calcium salts which are, however, statistically more active than the vehicle. Serum PTH is decreased under the lower limit of the normal range (10 pg/ml), between t60 and t120 for calcium carbonate and citrate and between t60 and t90 for calcium gluconolactate while the mean PTH values remain within the normal range throughout the study with calcium pidolate, the ossein-hydroxyapatite complex and the vehicle. In conclusion, all calcium preparations significantly increase serum calcium and decrease serum parathormone, compared to what is observed after oral intake of a vehicle. However, significant differences in suppression of parathormone are observed between the different calcium preparations and might be of importance for their clinical use.

Administration, Oral↗
PubMed1997

Postvaccinal immune response to regimens of Newcastle disease vaccination by filter paper sampling technique.

Seven hundred and ten blood samples were collected at random from commercial layers in Tamil Nadu on Whatman filter paper No. 1 instead of the conventional method of serum collection. The birds were subjected to different Newcastle disease (ND) vaccination schedules and samples were collected to study the vaccinal response to ND at field level. Eluates were obtained from sample areas of filter paper using Brij-35 solution [detergent] and subjected to the micro haemagglutination inhibition (HI) test for ND antibodies. The HI titre ranged from less than 2(4) to 2(9). The possible causes of poor immune response to ND vaccinations are discussed.

Agglutination Tests↗
PubMed1997

Prediction of bone loss rate in healthy postmenopausal women.

Prevention of fractures is the only way to drastically reduce osteoporosis-related health expenditures. In order to optimize the cost/benefit ratio of a strategy of prevention, it is essential to identify, as early as possible, women who will develop fractures later in their life. Therefore, and since postmenopausal bone loss is an asymptomatic process, screening procedures should detect, at the time of the menopause, women whose postmenopausal bone loss is higher than the mean, and will, a couple of years later, exhibit a low mineral content and a subsequent high risk for fractures. For 3 years we have followed a cohort of 92 healthy women who had undergone menopause less than 36 months previously. By a multivariate discriminant analysis based on the differences in lumbar bone density, assessed by dual photon absorptiometry, and in a few routine biochemical parameters (serum phosphorus, estrone, androstenedione, and urine calcium) observed during the first 6 months of the study, we have been able to correctly predict the rate of spinal bone loss, observed at the end of the 3 years, in 76% of the subjects. All of the women who presented a bone loss higher than 10% over the 3 years were correctly isolated by our discriminant functions after 6 months of follow-up. We conclude that a measurement of lumbar bone mineral density coupled with a few routine biochemical determinations, repeated twice at a 6-month interval in healthy postmenopausal women, can isolate 100% of postmenopausal "fast bone losers" with an overall specificity of 76%.

Absorptiometry, Photon↗
PubMed1997

Effect of the environment on fetal skin wound healing.

Skin wound healing has been shown to be a different process in the fetus than in the adult animal. Some of these differences have been attributed to the unique fetal environment (i.e., amniotic fluid). The aim of the present study is to compare fetal skin healing in intraamniotic and extraamniotic wounds. A fetal rabbit model has been used in which three types of skin wounds were induced on 23-day-old fetuses in contact with either amniotic fluid or maternal peritoneal fluid. The wounds consisted of a sutured skin incision, a nonsutured incision, and an electrocautery burn. Seven days later all wounds were examined mechanically (scar resistance), biochemically (collagen and noncollagen protein concentration), and histologically. Biochemical and growth factor studies of both environments, the amniotic and the peritoneal fluids, were also conducted. The results showed excellent healing by first intention and absence of healing by second intention in both environments, greater scar resistance in the intraperitoneally positioned fetal wounds, and a higher concentration of insulin-like growth factor-1 (IGF-1) in the peritoneal fluid than in the amniotic fluid. It can be concluded that fetal skin wounds in contact with peritoneal fluid show the same healing pattern as in the natural fetal environment (amniotic fluid). The higher concentration of IGF-1 in the peritoneal fluid suggests that this growth factor, through its relationship with the growth hormone, plays a role in increasing the scar resistance of fetal skin wounds in contact with maternal peritoneal fluid.

Amniotic Fluid↗
PubMed1997

Psychological approaches during conscious sedation. Hypnosis versus stress reducing strategies: a prospective randomized study.

Stress reducing strategies are useful in patients undergoing surgery. Hypnosis is also known to alleviate acute and chronic pain. We therefore compared the effectiveness of these two psychological approaches for reducing perioperative discomfort during conscious sedation for plastic surgery. Sixty patients scheduled for elective plastic surgery under local anesthesia and intravenous sedation (midazolam and alfentanil upon request) were included in the study after providing informed consent. They were randomly allocated to either stress reducing strategies (control: CONT) or hypnosis (HYP) during the entire surgical procedure. Both techniques were performed by the same anesthesiologist (MEF). Patient behavior was noted during surgery by a psychologist, the patient noted anxiety, pain, perceived control before, during and after surgery, and postoperative nausea and vomiting (PONV). Patient satisfaction and surgical conditions were also recorded. Peri- and postoperative anxiety and pain were significantly lower in the HYP group. This reduction in anxiety and pain were achieved despite a significant reduction in intraoperative requirements for midazolam and alfentanil in the HYP group (alfentanil: 8.7 +/- 0.9 microg kg(-1)/h(-1) vs. 19.4 +/- 2 microg kg(-1)/h(-1), P < 0.001; midazolam: 0.04 +/- 0.003 mg kg(-1)/h(-1) vs. 0.09 +/- 0.01 mg kg(-1)/h(-1), P < 0.001). Patients in the HYP group reported an impression of more intraoperative control than those in the CONT group (P < 0.01). PONV were significantly reduced in the HYP group (6.5% vs. 30.8%, P < 0.001). Surgical conditions were better in the HYP group. Less signs of patient discomfort and pain were observed by the psychologist in the HYP group (P < 0.001). Vital signs were significantly more stable in the HYP group. Patient satisfaction score was significantly higher in the HYP group (P < 0.004). This study suggests that hypnosis provides better perioperative pain and anxiety relief, allows for significant reductions in alfentanil and midazolam requirements, and improves patient satisfaction and surgical conditions as compared with conventional stress reducing strategies support in patients receiving conscious sedation for plastic surgery.

Adult↗
PubMed1997

Increase in cytokine production (IL-1 beta, IL-6, TNF-alpha but not IFN-gamma, GM-CSF or LIF) by stimulated whole blood cells in postmenopausal osteoporosis.

Postmenopausal osteoporosis is a progressive disorder characterized by a decreased bone mass and increased susceptibility to fractures. Several investigations have suggested that one of the mechanisms through which estrogen prevents bone loss was a modulation on secretion or release of various cytokines that are known to influence bone remodeling, even if some recent data have challenged this hypothesis. However, in established osteoporosis, the possibility that enhanced cytokines activity may account for the progression of this disease remains unclear and controversial. We sought here to determine whether production of IL-1 beta, IL-6, TNF-alpha, IFN-gamma, GM-CSF and LIF, after direct stimulation in whole blood, was different in healthy (n = 30) or osteoporotic postmenopausal women (n = 24) and whether lumbar bone density (1-BMD) correlated with the values of cytokine production observed in these conditions. A significant difference was observed between the osteoporotic and control subjects for IL-1 beta (p < 0.0001), IL-6 (p < 0.001) and TNF-alpha (p = 0.027) productions, the values being higher in the osteoporotic women. No significant differences between the groups were observed for IFN-gamma (p = 0.51), GM-CSF (p = 0.70) or LIF (p = 0.97). In the whole population, statistically significant negative correlations were observed between lumbar BMD and IL-1 beta (r = -0.46) (p < 0.0005), IL-6 (r = -0.50) (p < 0.0001) and TNF-alpha (r = -0.39) (p < 0.005) production while no such correlations were observed for IFN-gamma, GM-CSF or LIF. In conclusion, the study of cytokine production by immune cells cultured in autologous whole blood suggests that in women more than 10 years past the menopause and presenting a decrease in lumbar bone density corresponding to the new WHO definition of "osteoporosis', production of IL-1 beta, IL-6 and TNF-alpha is still increased compared to controls matched for age and ovarian function, while no differences are reported for IFN-gamma, GM-CSF or LIF production.

Bone Density↗
PubMed1997

Plasma estradiol concentrations and pharmacokinetics following transdermal application of Menorest 50 or Systen (Evorel) 50.

OBJECTIVES: In order to compare the pharmacokinetics of two transdermal estrogen replacement therapy (ERT) systems designed to release 50 micrograms 17 beta-estradiol/day, two studies were performed in healthy postmenopausal volunteers. METHODS: Both studies had a cross-over design and incorporated a 1-week wash-out period between treatments. In the first study, Menorest 50 and Systen 50 (Evorel 50) were compared over four days of application in 30 women. In the second, 13 women wore each of the two systems for a total of 12 days each (three patches each for 4 days), and comparison was made during the third patch period (steady state, between days 8 and 12). Plasma 17 beta-estradiol levels were assayed using specific direct radioimmunoassays, and pharmacokinetic parameters were calculated by standard methods. All the samples of the first study were re-analysed using a different radioimmunoassay and the results of both assays were compared. RESULTS: In both studies, plasma 17 beta-estradiol levels rose at a comparable rate and reached similar peak levels with each of the two formulations. Levels then remained relatively constant throughout both evaluation periods with Menorest 50, but began to decline after 12 hours in the first study and after 30 h under steady state conditions in the second study with Systen 50. The difference between the two products was statistically significant in both studies. Analysis of pharmacokinetic parameters confirmed the greater bioavailability of Menorest 50. In addition, 17 beta-estradiol levels remained within the suggested therapeutic ranges for relief of acute symptoms and protection against osteoporosis for longer periods of time with Menorest 50 than with Systen 50. CONCLUSION: Since the acute efficacy, long-term protective effects, side effects and risks associated with ERT may depend on critical threshold plasma levels, much attention should be paid to the pharmacokinetic profiles of different formulations. The comparison of these two different radioimmunoassays demonstrates the comparability of their results.

Administration, Cutaneous↗
PubMed1997

Education and training in health informatics: guidelines for European curricula.

Guidelines are suggested for European curricula in Health Informatics that apply to both healthcare professionals and health administrative staff. These guidelines are the results of in-depth discussions and thoughts of the EU-EDUCTRA concerted action. Emphasis is placed on the way information is generated in the health domain. The guidelines also consider the various actors, their position and role in the healthcare structure. Characteristics of and operations on health information are discussed. Data quality control, ethical issues, benefits and potential caveats related to health information are also outlined. The article concludes with a list of possible applications.

Administrative Personnel↗
PubMed1997

Adult groin hernias: new insight into their biomechanical characteristics.

The biomechanical properties of the transversalis fascia and rectus abdominis aponeurosis were assessed in adult groin hernias, using a computerized-suction device (Cutometer) equipped with a 2-mm probe. Evaluations were made ex vivo on fresh samples collected from 63 patients with unilateral or bilateral hernias and 30 control subjects without hernias. Under 50 and 200 mbar suctions, there was no statistical difference between the overall mechanical properties of control and patient aponeuroses. For both 50 and 200 mbar suctions, the maximum distension (MD) and the biological elasticity (BE) of fasciae from direct hernias were significantly increased, compared with control fasciae. In the same comparison, the MD-50 and -200 and the BE-50 of patient fasciae from the non-herniated sides were also significantly increased. It is concluded that the presently reported biomechanical alterations seem to be the cause and not the consequence of the hernias. These data suggest that a functional connective tissue pathology probably plays a role in the genesis of groin hernias.

Adult↗
PubMed1997

Effect of potassium channel openers on the firing rate of hippocampal pyramidal cells and A10 dopaminergic neurons in vitro.

The effect of four KATP channel openers (KCOs) on the firing rate of CA1 pyramidal cells and A10 dopaminergic neurons was investigated using extracellular recording techniques in rat brain slices. Pinacidil, lemakalim, diazoxide and a new compound, BPDZ44, had an inhibitory effect on the electrical activity of CA1 pyramidal cells. They all had a similar potency. Only BPDZ44 and diazoxide inhibited the firing rate of A10 dopamine neurons. The sulfonylurea glipizide (1 microM) antagonized the effect of BPDZ44 and diazoxide on A10 neurons but failed to antagonize the effect of KCOs on CA1 pyramidal cells. These results show that differences exist among KCOs in their ability to decrease the electrical activity of various populations of central neurons.

Action Potentials↗
PubMed1997

Sepsis and serum cytokine concentrations.

OBJECTIVE: To look for relationships between the classification of sepsis and plasma cytokine concentrations. DESIGN: Prospective, consecutive entry study of patients meeting severe sepsis criteria and having bacteriologically documented infections. SETTING: University hospital, surgical intensive care unit. PATIENTS: Fifty consecutive patients developing severe sepsis or septic shock between December 1991 and December 1993. MEASUREMENTS AND MAIN RESULTS: Concentrations of tumor necrosis factor, interleukin (IL)-6, IL-8, and leukemia inhibitory factor were measured by immunoradiometric assay in the plasma of patients as soon as they developed severe sepsis or septic shock. Septic shock patients were divided into three groups in a blinded fashion (i.e., without knowing the results of the concentrations of cytokines), according to the presence of sustained hyperlactacidemia and to the rapidity of the onset of sepsis. Peak concentrations of all cytokines were statistically different between severe sepsis and septic shock patients. This finding was almost exclusively due to the data from patients with rapid onset of septic shock, who demonstrated very high but transient cytokine concentrations. Septic shock patients may thus have different profiles in the time course of their cytokine concentrations. The transient, high peak concentrations of cytokines were also related to transient leukopenia. Among the cytokines measured, IL-8 appeared to be the one that correlated best with lactacidemia, the presence of disseminated intravascular coagulation, severe hypoxemia, the Acute Physiology and Chronic Health Evaluation II score, and mortality rate. CONCLUSIONS: According to the profiles of the cytokines, septic shock patients do not represent a homogeneous population. These profiles should be described in order to distinguish between patients, and the profiles may be useful to identify those patients susceptible to new therapies.

APACHE↗
PubMed1997

Scintigraphic visualization of intrathecal liposome biodistribution.

BACKGROUND: Liposomes containing local anaesthetics have been administered intrathecally and in the epidural space. Poor attention has been given to the pharmacokinetics of liposomes as drug carriers. Therefore, we observed the biodistribution of liposomes after intrathecal injection in rats by scintigraphic imaging during 24 h. METHODS: We administered 99mTc-labeled multilamellar (MLV) and small unilamellar vesicles (SUV) of defined size and volume dispersities into the cerebrospinal fluid at the lumbar level. Those vesicles were free of contamination by radiolabeled colloids as visualized by light and electron microscopy and of neurotoxic products from phosphatidylcholine hydrolysis and peroxidation, both during the preparation process and after 24 h incubation in cerebrospinal fluid at 37 degrees C in vitro. RESULTS: SUV immediately diffused from the lumbar site of injection to the head and were cleared between 1 and 24 h after injection. MLV were cleared more slowly from the spinal space and appeared in the head region 1 h after injection where they accumulated up to 24 h. These differences were explained in terms of vesicle sizes and volumes. SUV with 0.05 micron diameters were rapidly absorbed into the blood through the arachnoid granulations. In contrast, particles larger than the upper size limit of the arachnoid granulations permeability (+/- 8 microns) could accumulate in the head with a slow elimination rate. CONCLUSION: This difference in clearance from the intrathecal space outlines the importance of defining the size of the liposomes, the distribution of a tracer or a drug inside the liposomal preparation, the chemical stability and the absence of toxic degradation products of liposome formulations before clinical use.

Animals↗
PubMed1997

Optimized transcranial Doppler technique for the diagnosis of cardiac right-to-left shunts.

Transcranial Doppler sonography (TCD) is a simple method to detect a right-to-left cardiac shunt, although standardized procedures do not exist. In this study 69 patients were tested according to predetermined criteria and procedures (cluster of > 10 microbubbles, duration between injection in the cubital vein and detection in the middle cerebral artery [MCA] < or = 10 sec). Agitated saline solution was compared to oxypolygelatine, a plasma volume expander, as contrast media. Valsalva's maneuver and coughing were used to provoke right-to-left cardiac shunting, detected by TCD, transthoracic echocardiography (TTE), and transesophageal echocardiography (TEE). Oxypolygelatine caused a significantly higher number of microbubbles in the right atrium and MCA than did the saline solution, leading to a greater diagnostic reliability of TCD (paired t test, p < 0.001). Coughing did not provoke right-to-left cardiac shunts (x2 analysis, p < 0.001). The technique used for carrying out Valsalva's maneuver was important for the detection of right-to-left cardiac shunts. Twenty-five right-to-left shunts were diagnosed with TCD and 18 with TTE (36 vs 26%; x2 analysis, p = 0.1). The findings indicate that TCD when properly done is highly sensitive and specific for the diagnosis of right-to-left cardiac shunts.

Adult↗
PubMed1997

Prenatal hormones alter antioxidant enzymes and lung histology in rats with congenital diaphragmatic hernia.

Prenatal administration of dexamethasone (Dex) and thyrotropin-releasing hormone (TRH) synergistically enhances lung maturity, but TRH suppresses the antioxidant enzyme activity. Prenatal hormonal therapy improves alveolar surfactant content and lung compliance in rats with congenital diaphragmatic hernia (CDH). In full term neonatal rats with CDH we studied the effects of prenatal Dex or Dex+TRH on antioxidant enzyme activity at birth, on survival, and on lung morphometry after 4 h of ventilation with 100% O2. CDH was induced by administration of 2,4-dichlorophenyl-p-nitro-phenylether (Nitrofen) on gestational day 10. Dex+TRH-treated CDH rats had lower activity of glutathione reductase after birth than did sham-treated CDH pups. Dex-treated and sham-treated pups had similar antioxidant enzyme activity. Hormonal treatment did not change survival during ventilation. The average airspace volume increased in Dex-treated CDH pups after ventilation, with a small synergistic effect after addition of TRH. On the basis of our findings, we speculate that prenatal administration of Dex is the best choice to improve lung maturity and airspace volume in CDH patients.

Animals↗