Asymptomatic hyperuricemia: impact of ultrasonography

Thirty-five patients (23 males) with asymptomatic hyperuricemia for at least two years underwent two-dimensional ultrasonography of knees and ankles. Urate deposits (tophi) in tendons, synovium, and other soft tissues were detected in 12 patients (34%). Increased vascularity (inflammation) was evident in 8 of these patients (23%). Tophi were more frequently found in knees than in ankles and were especially prevalent in the distal patellar tendon. The presence of tophi was unrelated to the known duration of hyperuricemia (mean, 5 years). Ultrasonography allows detection of tophi and inflammation in a third and in a fourth, respectively, of asymptomatic hyperuricemic patients.

Modelling adaptative volumetric finite growth in patient-specific residually stressed arteries

Understanding the functional performance of vascular tissue is taking a rising importance due to the increasing impact of cardiovascular diseases in developed countries. Currently available medical imaging acquisition techniques, combined with computer modelling allow patient-specific simulations of customized geometries that may help in medical diagnosis and therapeutic treatment. In this work we show methodology to develop patient-specific simulations. Particular features of arteries such as their multilayered structure, as well as the non-linear behaviour of the arterial tissue are considered. A strategy based on the decomposition of the deformation gradient tensor is followed in order to include residual stresses in the real geometry. By means of this technique, it is also possible to model the adaptative growth of the artery neglecting the developing process from the embryo state.

Methylmalonic acidaemia: examination of genotype and biochemical data in 32 patients belonging to mut, cblA or cblB complementation group

Methylmalonic acidaemia (MMA) is a genetic disorder caused by defects in methylmalonyl-CoA mutase or in any of the different proteins involved in the synthesis of adenosylcobalamin. The aim of this work was to examine the biochemical and clinical phenotype of 32 MMA patients according to their genotype, and to study the mutant mRNA stability by real-time PCR analysis. Using cellular and biochemical methods, we classified our patient cohort as having the MMA forms mut (n = 19), cblA (n = 9) and cblB (n = 4). All the mut (0) and some of the cblB patients had the most severe clinical and biochemical manifestations, displaying non-inducible propionate incorporation in the presence of hydroxocobalamin (OHCbl) in vitro and high plasma odd-numbered long-chain fatty acid (OLCFA) concentrations under dietary therapy. In contrast, mut (-) and cblA patients exhibited a milder phenotype with propionate incorporation enhanced by OHCbl and normal OLCFA levels under dietary therapy. No missense mutations identified in the MUT gene, including mut (0) and mut (-) changes, affected mRNA stability. A new sequence variation (c.562G>C) in the MMAA gene was identified. Most of the cblA patients carried premature termination codons (PTC) in both alleles. Interestingly, the transcripts containing the PTC mutations were insensitive to nonsense-mediated decay (NMD).

Computer simulation of damage on distal femoral articular cartilage after meniscectomies

It is commonly accepted that total or partial meniscectomies cause wear of articular cartilages that leads to severe damage in a period of few years. This also produces alteration of the biomechanical environment and increases articular instability, with a progressive and degenerative arthrosic pathology. Due to these negative consequences, total meniscectomy technique has been avoided, with a clear preference for partial meniscectomies. Despite the better results obtained with this latter technique, it has been demonstrated that the knee still suffers progressive long-term wear, which alters the properties of the surface of articular cartilage. In this paper, a phenomenological isotropic damage model of articular cartilage is presented and implemented in a finite element code. We hypothesized that there is a relation between the increase of shear stress and cartilage degeneration. To confirm the hypothesis, the obtained results were compared to experimental ones. It is used to investigate the effect of meniscectomies on articular damage in the human knee joint. Two different situations were compared for the tibio-femoral joint: healthy and after meniscectomy. The distribution of damaged regions and the damage level distribution resulted qualitatively similar to experimental results, showing, for instance that, after meniscectomy, significant degeneration occurs in the lateral compartment. A noteworthy result was that patterns of damage in a total meniscectomy model give better agreement to clinical results when using relative increases in shear stress, rather than an absolute shear stress criterion. The predictions for partial meniscectomies indicated the relative severity of the procedures.

Reproducibilidad de la prueba de sobrecarga oral de glucosa en pacientes con glucosa alterada en ayunas

BACKGROUND AND OBJECTIVES

Impaired fasting glucose (IFG) is defined by a fasting glucose between 5.6 and 6.9 mmol/l in subjects with no known diabetes. The present study objectives were: a) to analyze the glucose tolerance test (GTT) reproducibility and b) to assess this test's diagnostic classification agreement.

PATIENTS AND METHOD

Cross-sectional study in adult patients diagnosed with IFG. Study subjects underwent a 75 g GTT in two occasions.

RESULTS

Fifty-nine patients were studied. The interval between GTT tests was 37 +/- 26 days. Fasting and post-GTT plasma glucose intra-individual variation coefficients were 6.9 and 31.0%, respectively. Diagnostic agreement between the two tests (normal tolerance vs. abnormal tolerance) was measured using the kappa index: 0.62 (95% CI 0.42-0.82). Agreement ranged from 80% (95% CI, 70-90%) to 83% (95% CI, 73-93%) depending on whether the first GGT results were abnormal or normal, respectively.

CONCLUSIONS

GTT reproducibility is moderate in patients diagnosed with IFG. Considering this fact, perhaps this test should be repeated before therapeutic decisions are made.

Treatment with tiludronate has a similar effect to risedronate on Paget's disease activity assessed by bone markers and bone scintigraphy

OBJECTIVE

To compare the effects of tiludronate and risedronate on Paget's disease activity assessed by biochemical markers of bone turnover and quantitative bone scintigraphy.

METHODS

An open-labeled non-randomized study was performed in 49 patients with Paget's disease who had completed treatment with tiludronate (400 mg/d) for 3 months (28 patients) or risedronate (30 mg/d) for 2 months (21 patients). Biochemical markers of bone turnover, including serum total alkaline phosphatase (TAP), bone alkaline phosphatase (BAP), procollagen type I N propeptide (PINP) and urinary N-terminal cross-linking telopeptide of type I collagen (NTX) were measured at baseline and at 6 and 12 months after the end of treatment. Quantitative bone scintigraphy at baseline and 6 months after the end of treatment was performed in all patients obtaining a scintigraphic activity index (SAI).

RESULTS

At baseline there were no significant differences in disease activity between both groups of patients, since markers of bone turnover as well as SAI were similar in both groups. The effects of tiludronate and risedronate in reducing the biochemical markers of bone turnover were comparable at 6 months (tiludronate vs risedronate: TAP -52% vs -43%; BAP -69% vs -56%; PINP -68% vs -63%; NTX -62% vs -59%) and at 12 months after the end of treatment (tiludronate vs risedronate: TAP -47% vs -36%; BAP -57% vs -46%; PINP -57% vs -52%; NTX -51% vs -52%). The effects of tiludronate and risedronate on SAI were also similar 6 months after the discontinuation of treatment. In addition, the percentage of patients who showed normalized serum TAP levels at 6 months after treatment were similar with both agents (74% with tiludronate and 70% with risedronate).

CONCLUSION

Tiludronate and risedronate given at the currently recommended dosages induce similar responses in Paget's disease activity.

Hypophosphatemia in postoperative patients with total parenteral nutrition: influence of nutritional support teams

PURPOSE, SETTING AND SUBJECTS: We conducted a prospective, descriptive study of postoperative patients under total parenteral nutrition controlled by a Multidisciplinary Nutritional Support Team in a tertiary care hospital. Between january 2002 and november 2003. Data of nutritional status, nutritional support, hypophosphatemia, electrolyte and metabolic complications were reviewed.

RESULTS

215 postoperative patients (63.3% male, 68 +/- 13.9 years old, 47.4% neoplasia). were included. Nutritional support according nutritional needs was made during fasting 14.2 +/- 18.4 days. Mild-moderate initial malnutrition was present in 58% of patients. 18.1% developed postoperative hypophosphatemia 96 hours after starting total parenteral nutrition containing phosphate. 37.7% patients showed moderated and 6.5% severe hypophosphatemia. Nutritional intervention corrected hypophosphatemia (p < 0.001). Factors related to hypophosphatemia were hypokalemia, hypomagnesemia, hypercalcemia, female sex, neoplasia, 96-hour postoperative period and duration of nutrition.

CONCLUSIONS

Prevalence of hypophosphatemia in postoperative patients with total parenteral nutrition is high and needs timely monitoring. The intervention of Multidisciplinary Nutritional Support Team is effective detecting and correcting postoperative hypophosphatemia.

Toxicokinetics of lambda-cyhalothrin in rats

The toxicokinetics of lambda-cyhalothrin after single 20 mg kg(-1) oral and 3 mg kg(-1) intravenous doses were studied in rats. Serial blood samples were obtained after oral and intravenous administration. Liver, brain, spinal cord, sciatic nerve, vas deferens, anococcygeus and myenteric plexus tissue samples were also collected. Plasma, liver, hypothalamus, cerebellum, medulla oblongata, frontal cortex, striatum, hippocampus, midbrain, spinal cord, vas deferens, anococcygeus, myenteric plexus and sciatic nerve concentrations of lambda-cyhalothrin were determined by HPLC. The plasma and tissue concentration-time data for lambda-cyhalothrin were found to fit a two-compartment open model. For lambda-cyhalothrin, the elimination half-life (T1/2beta) and the mean residence time from plasma were 7.55 and 8.55 h after i.v. and 10.27 and 14.43 h after oral administration. The total plasma clearance was not influenced by dose concentration or route and reached a value of 0.060l h(-1)kg(-1). After i.v. administration, the apparent volume of distribution and at steady state were 0.68 and 0.53l kg(-1), suggesting a diffusion of the pyrethroid into tissue. After oral administration, lambda-cyhalothrin was extensively but slowly absorbed (Tmax, 2.69 h). The oral bioavailability was found to be 67.37%. Significant differences in the kinetic parameters between nervous tissues and plasma was observed. The maximum concentrations in hypothalamus (Cmax, 24.12 microg g(-1)) and myenteric plexus (Cmax, 25.12 microg g(-1)) were about 1.5 times higher than in plasma (Cmax, 15.65 microg ml(-1)) and 1.3 times higher than in liver (Cmax, 18.42 microg ml(-1)). Nervous tissue accumulation of lambda-cyhalothrin was also reflected by the area under the concentration curve ratios of tissue/plasma (liver). The T1/2beta for lambda-cyhalothrin was significantly greater for the nerve tissues, including neuromuscular fibres, (range 12-26 and 15-34 h, after i.v. and oral doses) than for plasma (7.55 and 10.27 h, respectively).

A three-dimensional finite element analysis of the combined behavior of ligaments and menisci in the healthy human knee joint

We present here a three-dimensional FE model of the healthy human knee that included the main structures of the joint: bones, all the relevant ligaments and patellar tendon, menisci and articular cartilages. Bones were considered to be rigid, articular cartilage and menisci linearly elastic, isotropic and homogeneous and ligaments hyperelastic and transversely isotropic. Initial strains on the ligaments and patellar tendon were also considered. This model was validated using experimental and numerical results obtained by other authors. Our main goal was to analyze the combined role of menisci and ligaments in load transmission and stability of the human knee. The results obtained reproduce the complex, nonuniform stress and strain fields that occur in the biological soft tissues involved and the kinematics of the human knee joint under a physiological external load.

A finite element simulation of the effect of graft stiffness and graft tensioning in ACL reconstruction

BACKGROUND

The anterior cruciate is the most frequent knee ligament to be totally disrupted. Surgical reconstruction of the anterior cruciate ligament is a common practice to treat the disability or chronical instability of knees due to anterior cruciate ligament insufficiency. Some of the factors that influence the success or failure of the anterior cruciate ligament reconstruction are the integrity of secondary restraints, the preoperative laxity of the knee, the status of the articular and meniscal cartilages, the selection of the graft material, the surgical technique, the graft tension and the postoperative rehabilitation.

METHODS

In this paper we present and discuss the results obtained with a three-dimensional finite element model of the human knee joint corresponding to different aspects of human anterior cruciate ligament reconstruction. In particular, this model was used to investigate the effect of graft stiffness and graft tensioning on the knee joint biomechanics. The initial graft tension was set to 0, 20, 40 or 60 N with the knee at 0 degrees , 30 degrees and 60 degrees of flexion. Three different stiffnesses corresponding to those of patellar tendon, gracilis and quadrupled semitendinosus grafts were analyzed.

FINDINGS

The resulting kinematics in each of these cases under an anterior load of 134 N was compared to that of the intact knee. The obtained results showed that, after reconstruction, the closest anterior tibial translation to that of the intact knee is obtained with a bone-patellar tendon-bone graft with a pretension of 60 N.

INTERPRETATION

However, this initial tension produces an important additional stress in the graft during the knee movement. This may cause problems in revascularization and remodelling during the postoperative healing process. A lower pretension of about 40 N should therefore be recommended in the present conditions.

Finite element analysis of the effect of meniscal tears and meniscectomies on human knee biomechanics

BACKGROUND

Many authors have suggested that the high levels of shear and tensile stresses that appear in the articular cartilage after meniscectomy are partly responsible for cartilage pathologies, such as osteoarthrosis.

METHODS

In this paper, we investigate the effect of meniscal tears and meniscectomies on the human knee joint. Solid models of the tibia, femur, menisci and cartilage were generated from MRI images. A three-dimensional finite element model was developed that included the femur, tibia, cartilage layers, menisci and ligaments. The femur and tibia were considered to be rigid, the articular cartilage and menisci to be linearly elastic, isotropic and homogeneous and the ligaments were modelled as hyperelastic. Three different situations were compared: a healthy tibio-femoral joint, a tibio-femoral joint with tears in one meniscus and a tibio-femoral joint after meniscectomy.

FINDINGS

The minimal principal stresses corresponding to a compressive load at 0 degrees flexion were obtained for the posterior zone of the medial meniscus and the corresponding region of the articular cartilage. Under an axial femoral compressive load, the maximal contact stress in the articular cartilage after meniscectomy was about twice that of a healthy joint.

INTERPRETATION

This fact could partially explain the cartilage damage and degeneration that have been observed after meniscectomy.

[Prevalence of malnutrition in outpatients with stable chronic obstructive pulmonary disease]

OBJECTIVE

To determine the prevalence of malnutrition in outpatients with stable chronic obstructive pulmonary disease (COPD) followed at a respiratory clinic.

MATERIAL AND METHOD

In this prospective study, we assessed the nutritional status of consecutive outpatients with stable COPD by investigating various anthropometric parameters. Patients were malnourished (low body weight) if their body mass index was within the bottom quartile of a reference population. Muscle mass was determined from the midarm muscle area and if this mass was at or within the bottom quartile, muscle wasting was present. Albumin and transferrin plasma concentrations were used as a measure of visceral protein stores. Fat stores were assessed from body fat and if this value was at or within the bottom quartile, calorific malnutrition was present. All patients underwent arterial blood gas sampling at rest and spirometry.

RESULTS

A total of 178 patients--one woman (0.6%) and 177 men (99.4%)--were enrolled in the study, with a mean (SD) age of 69 (9) years. We found low body weight in 19.1% of the patients, muscle wasting in 47.2%, visceral protein depletion in 17.4%, and fat depletion in 19.1%. Of the patients with normal weight, 62.9% showed muscle wasting. The proportion of patients with a body mass index or midarm muscle area at or within the bottom quartile increased significantly with increased bronchial obstruction (P<.001 and P=.015, respectively), though 35.7% of the patients showed muscle wasting even when COPD was mild.

CONCLUSIONS

Many patients with stable COPD suffer malnutrition. Nutritional state is worse with more severe COPD. Depletion involves both fat stores and muscle and visceral protein stores, but the greatest effect is seen in muscle wasting. A significant number of patients with normal weight also suffer muscle wasting. Although changes in body composition were common in our patients, low body weight was less prevalent than has been reported for populations in countries that are socially and economically similar to Spain.

Pharmacokinetics of amoxycillin and the rate of depletion of its residues in pigs

Six pigs were used in a two-period crossover study to investigate the pharmacokinetics of amoxycillin after single intravenous and oral doses of 20 mg/kg bodyweight. Twelve pigs were used to study the residues of the drug in muscle, kidney, liver and fat after they had received daily oral doses of 20 mg/kg amoxycillin for five days. The mean (sd) elimination half life (t1/2beta) and mean residence time of amoxycillin in plasma were 3.38 (0.30) and 3.54 (0.43) hours, respectively, after intravenous administration and 4.13 (0.50) and 4.47 (0.30) hours, respectively, after oral administration. After oral administration, the maximum plasma concentration (Cmax) was 7.37 (0.42) microg/ml and it was reached after 0.97 (0.29) hours. Six days after the last oral dose, the mean concentration of amoxycillin in the pigs' kidneys was 21.38 ng/g and in the liver it was 12.32 ng/g, but no amoxycillin could be detected in fat or muscle; the concentrations of amoxycillin in edible tissues were less than the European Union maximal residue limit of 50 microg/kg.

A Comparative Solid-Phase Extraction Study for the Simultaneous Determination of Fluoxetine, Amitriptyline, Nortriptyline, Trimipramine, Maprotiline, Clomipramine, and Trazodone in Whole Blood by Capillary Gas--Liquid Chromatography with Nitrogen-Phosphorus Detection

This paper reports the simultaneous detection of the seven antidepressants fluoxetine, amitriptyline, nortriptyline, trimipramine, maprotiline, clomipramine, and trazodone in whole blood at concentration levels of 100-2000 ng/mL by gas chromatography with a nitrogen-phosphorus detector (GC-NPD). A comparative and validation study using two solid-phase extraction (SPE) columns, Chem Elut and Bond Elut Certify, were developed regarding their recovery, precision, sensitivity, and matrix purification efficiency. The Chem Elut columns, a diatomaceous earth, are closely related to conventional liquid-liquid extraction. The Bond Elut Certify columns, more recently developed in the market, are a mixed SPE: reversed-phase and cation exchange sorbent. Recoveries of the compounds using Chem Elut columns at 500 ng/mL were in the range 30-50%, with intra- and interassay precisions of less than 9% and 17%, respectively. Limits of detection (LODs) and quantitation (LOQs) ranged from 13 to 146 ng/mL and from 44 to 485 ng/mL, respectively. Recoveries of the compounds using Bond Elut Certify columns at 500 ng/mL were in the range 59-84% with intra- and interassay precisions of less than 8% and 11%, respectively. LODs and LOQs ranged from 8 to 67 ng/mL and from 25 to 223 ng/mL, respectively. An excellent linearity was observed with both extraction procedures from the LOQs up to 2000 ng/mL. Higher recoveries, cleaner extracts, better sensitivity, better precision, and less solvent consumption and disposal were achieved for the screening of these antidepressants with the use of the mixed SPE Bond Elut Certify compared with Chem Elut columns.

Poly-beta-hydroxyalkanoates consumption during degradation of 2,4,6-trichlorophenol by Sphingopyxis chilensis S37

AIMS

To analyse the possible effect of poly-beta-hydroxyalkanoate (PHA) consumption on 2,4,6-trichlorophenol (2,4,6-TCP) degradation during starvation by Sphingopyxis chilensis S37 strain, which stores PHAs and degrades 2,4,6-TCP.

METHODS AND RESULTS

The strain was inoculated in saline solution supplemented with 2,4,6-TCP (25-400 microm). Chlorophenol degradation was followed both spectrophotometrically and by chlorine released; viable bacterial counts were also determined. Cells starved for 24, 48 or 72 h were incubated with 25 microm of 2,4,6-TCP and PHA in cells investigated by spectrofluorimetric and flow cytometry. Results demonstrated that starvation decreased the ability to degrade 2,4,6-TCP. After 72 h of starvation, degradation of 2,4,6-TCP decreased to less than 10% and the relative PHA content diminished to ca 50% during the first 24 h.

CONCLUSION

Utilization of PHA may be an important factor for the degradation of toxic compounds, such as 2,4,6-TCP, in bacterial strains unable to use this toxic compound as carbon and energy source.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study describing a relationship between intracellular PHA consumption and 2,4,6-TCP degradation. Therefore, PHAs provides an endogenous carbon and energy source under starvation and can play a significant role in the degradation of toxic compounds.

Acute nitrobenzene poisoning with severe associated methemoglobinemia: identification in whole blood by GC-FID and GC-MS

A rare fatal case of self-poisoning with nitrobenzene following oral ingestion is reported. On presentation to the hospital, severe methemoglobinemia (70%) was observed in an 82-year-old male who had ingested 250 mL of an unknown substance in the previous 24 h. Methylene blue and exchange transfusion were the therapeutic methods applied in the treatment of the methemoglobinemia. Forty-eight hours after ingestion, a blood sample was collected in ICU and sent to our laboratory. We detected that the blood contained 3.2 microg/mL of nitrobenzene. The determination of nitrobenzene was performed using the combination of GC-FID for screening analysis and quantitation and GC-MS for confirmation of the obtained results.

[CADASIL: a case with clinical, radiological, histological and genetic diagnoses]

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare inherited cerebrovascular disease. The onset of clinical symptoms occurs with migraine with aura, transient ischemic attacks, recurrent subcortical ischemic infarcts, neuropsychiatric changes reaching subcortical dementia. Brain magnetic resonance images show multiple deep cerebral infarcts in white matter and basal ganglia and diffuse leukoencephalopathy. Neuropathologic hallmark consists of deposition of small electron dense granular patches related to the basement membrane of vascular smooth muscle cells with degeneration of smooth muscle cells and media and luminal obliteration. Recently, the genetic characteristics of this disorder have been reported. Missense mutations in notch3 gene localized in chromosome 19 are involved in its pathogenesis. Only three families from Spain have been reported. Here we describe a patient with typical clinical symptoms, neuroimaging and pathology of CADASIL. C406T (Arg110Cys) mutation in notch3 gene was found. We comment on the clinical symptoms of different members of the patient's family.

Six years of experience in laparoscopic surgery of esophageal achalasia

BACKGROUND

We show the experience of 6 years in laparoscopic surgical therapy of esophageal achalasia, performing of the Heller-Dor or Heller-Toupet operation, with particular regard to the technical aspect.

METHODS

One hundred and ten laparoscopic interventions were done between November 1995 and December 2001. We studied operative time in hiatus approach, esophagocardiomyotomy, transoperative endoscopy, and anti-reflux procedure. We also analyzed the relation between complications and clinical evolution of disease with clinical stage.

RESULTS

The mean surgical time of the intervention is 138 min, and it is significantly increased by transoperative endoscopic control; conversion to open surgery was not necessary. Clinical results are classified as excellent in 103 patients. Morbidity was 6%.

CONCLUSION

This surgical procedure is a first line in the treatment of esophageal achalasia. It is necessary to have special care in early diagnostic cases to avoid electrosurgical injury.

Effect of ovaric hyper-stimulation on blood lymphocyte subpopulations, cytokines, leptin and nitrite among patients with unexplained infertility

PROBLEM

To determine the effect of ovarian stimulation on TH1, TH2 and natural killer (NK) lymphocytes, plasma cytokines, leptin and nitrite levels.

METHODS

Women with reproductive failure were studied during the implantation window, at baseline (n = 18) and under ovarian stimulation (gonadotropins + progesterone, n = 6).

CONTROLS

eight fertile women. Lymphocyte subpopulations and NK function were determined by flow cytometry. Interleukin-2 (IL-2), IL-4, IL-10, IFN-gamma, TNF-alpha, TGF-beta1 and leptin were measured by enzyme immunoassay (EIA); nitrite by the Griess reaction.

RESULTS

At baseline, patients had higher values of NK effectors, NK activity and plasma IFN-gamma and IL-2 than controls. Conversely, TGF-beta1 values were lower. Hormones induced leukocytosis. Under stimulation, THI CD4+ cells, NK effectors and function and plasma IFN-gamma and IL-2 decreased, while transforming growth factor (TGF)-beta1 increased. Other variables did not change.

CONCLUSION

The abnormal distribution of leukocytes, high TH1 cytokines and a low TGF-beta1 associated with reproductive failure, respond to ovarian stimulation, achieving total or partial normalization.

Simultaneous determination of viloxazine, venlafaxine, imipramine, desipramine, sertraline, and amoxapine in whole blood: comparison of two extraction/cleanup procedures for capillary gas chromatography with nitrogen-phosphorus detection

A comparative study for the simultaneous gas chromatographic (GC) resolution and detection of the six antidepressants viloxazine, venlafaxine, imipramine, desipramine, sertraline, and amoxapine in whole blood at concentration levels of 100-2000 ng/mL was developed. Two extraction/cleanup analytical procedures were compared regarding their recovery, precision, sensitivity and matrix purification efficiency. The first procedure consists of the employment of Chem Elut columns (diatomaceous earth) and is based on the principle of liquid-solid absorption extraction that is closely related to conventional liquid-liquid extraction. The second focuses on the use of Bond Elut Certify columns and a mixed SPE, reversed-phase and cation-exchange sorbent, more recently developed for the market. Each procedure required 2.0 mL of whole blood extraction and injection into a capillary GC equipped with a nitrogen-phosphorus detector. Mepivacaine was used as the extraction standard (surrogate), and prazepam was used as the chromatographic standard. No interferences were found, and the time for the chromatographic analysis was 16 min for one sample. Recoveries of the compounds using Chem Elut columns at 500 ng/mL were in the range of 28-74% with intra-assay and interassay precisions of less than 7% and 19%, respectively. Limits of detection (LOD) and quantitation (LOQ) ranged from 39 to 153 ng/mL and from 128 to 504 ng/mL, respectively. Recoveries of the compounds using Bond Elut Certify columns at 500 ng/mL were in the range of 64-86% with intra-assay and interassay precisions of less than 4% and 10%, respectively. LODs and LOQs ranged from 21 to 100 ng/mL and from 70 to 330 ng/mL, respectively. An excellent linearity was observed with both procedures from the LOQs up to 2000 ng/mL. The use of the reversed-phase and cation-exchange sorbent Bond Elut Certify showed advantages compared with Chem Elut columns for the screening of these antidepressants such as higher recoveries, cleaner extracts, better sensitivity, better precision, and less solvent consumption and disposal.

Antibiotic administration in patients with preterm premature rupture of membranes reduces the rate of histological chorioamnionitis: a prospective, randomized, controlled study

OBJECTIVE

To determine whether antibiotic administration in patients with preterm premature rupture of membranes is associated with a reduction in the rate of histological chorioamnionitis and funisitis.

METHODS

One hundred consecutive patients with preterm premature rupture of membranes and no labor between 24 and 34 weeks were invited to participate in this study. Eligible patients randomly received either clindamycin-gentamicin for 7 days or placebo, and were managed expectantly until 35 weeks unless fetal or maternal indications developed. Microbial invasion of the amniotic cavity was defined as the presence of a positive amniotic fluid culture obtained by transabdominal amniocentesis. Cervicovaginal infection was diagnosed when bacterial vaginosis or a positive culture for cervicovaginal pathogens or facultative bacteria associated with a significant increase in the white blood cell count were found. Histological chorioamnionitis was based on the observation of polymorphonuclear leukocyte infiltration of the chorionic plate or the extraplacental fetal membranes. Funisitis was diagnosed in the presence of polymorphonuclear leukocyte infiltration into the umbilical vessel walls or Wharton jelly. Statistics were performed using contingency tables.

RESULTS

Seventy-one patients with available histological study of the placenta were included. Thirty-five women received antibiotics and 36 were given placebo. Patients who received antibiotics had a significantly lower rate of histological chorioamnionitis than patients who received placebo (46% (16/35) vs. 69% (25/36), respectively; p < 0.05). This effect was more pronounced among women with microbial invasion of the amniotic cavity and/or cervicovaginal infection (58% vs. 89%, respectively; p < 0.01). Antibiotic therapy was associated with an increase in the frequency of placentas without histological abnormalities (29% vs. 6%; p < 0.01). The frequency of funisitis was not different between groups.

CONCLUSION

Administration of antibiotics in patients with preterm premature rupture of membranes is associated with a significant reduction in the incidence of histological chorioamnionitis but it does not modify the frequency of funisitis.

Occurrence and antimicrobial susceptibility of Ureaplasma parvum (Ureaplasma urealyticum biovar 1) and Ureaplasma urealyticum (Ureaplasma urealyticum biovar 2) from patients with adverse pregnancy outcomes and normal pregnant women

A recent phylogenetic analysis of Ureaplasma urealyticum resulted in the proposal to divide their 2 biovars into species. We used PCR to compare the distribution of species and the presence of the tet(M) and int-Tn resistance determinants in 63 strains of Ureaplasma spp. isolated from the amniotic fluid of patients with an adverse pregnancy outcome and in 22 strains obtained from the lower genital tract of healthy pregnant women. We also determined the antimicrobial susceptibility of the organisms to erythromycin and tetracycline. U. parvum was the most frequent Ureaplasma species detected in our study. Thus, 50/63 (79.4%) invasive isolates and 17/22 (77.3%) lower genital tract isolates corresponded to U. parvum, whereas 12/63 (19%) invasive isolates and 4/22 (18.2%) non-invasive strains corresponded to U. urealyticum. A mixture of species was found in 2 women. We found no significant differences in the antimicrobial susceptibility of isolates according to species or origin of isolation. Sixty-two strains of Ureaplasma spp. (74.7%) were susceptible to erythromycin, and 21 strains (25.3%) were intermediately susceptible. Sixty-eight isolates (81.9%) were susceptible to tetracycline, 2 strains (2.4%) were intermediate and 13 strains (15.7%) were resistant. DNA sequences related to the tet(M) determinant and the int-Tn gene were found in all tetracycline-resistant isolates.

An anisotropic internal-external bone adaptation model based on a combination of CAO and continuum damage mechanics technologies

In this work, a complete internal-external bone-remodelling scheme is presented and implemented into a finite element code. This model uses a combination of an anisotropic internal remodelling model based on a new Continuum "Damage-Repair" theory and an external adaptation approach that follows the idea, early introduced by Mattheck et al., to simulate the growth behaviour of biological systems, known as CAO method. This combined scheme qualitatively resembles most of the main features of the bone adaptive behaviour, like the bone mass distribution (heterogeneity and porosity), the directional internal structure (anisotropy), the alignment of the microstructure with the constitutive principal directions and these with those of the stress tensor when permanently loaded by a unique stress state (Wolff's law). It is also thermodynamically consistent, fulfilling a principle of minimum mechanical dissipation. Finally, the comparison between the predicted results and the ones obtained by different experimental tests allows us to conclude that this model is able of reproducing qualitatively the global behaviour of bone tissue when subjected to external mechanical loads.