Study of Two Grafting Methods for Obtaining a 3-Aminopropyltriethoxysilane Monolayer on Silica Surface

In order to establish a 3-aminopropyltriethoxysilane (APTES) grafting procedure with limited number of APTESs noncovalently linked to the silica surface, two different methods of grafting (in acid-aqueous solution and in anhydrous solution) were compared. The grafted surface state was investigated by atomic force microscopy (AFM). The stability of the grafting was checked at different temperatures by AFM. Continuous and plane APTES grafted surfaces were successfully prepared using both grafting preparations. The grafting in an anhydrous solution behaves homogeneously and stably compared to the grafting in an acid-aqueous solution. Moreover, with anhydrous solution, results showed that a unique monolayer of APTES was grafted.

Leukocyte filtration fails to limit functional neutrophil activity during cardiac surgery

OBJECTIVE AND DESIGN

The beneficial effects of leukocyte filtration on the outcome of cardiac surgery with cardiopulmonary bypass (CPB) is probably due to the limitation of pathogenesis mediated by over-stimulated neutrophils. However, the influence of leukocyte filtration on the functional neutrophil activity has not been studied in detail. Therefore, by using different filtration timing strategies we determined neutrophil effector functions before and after the filter passage as well as blood surrogate markers for neutrophil activation.

METHODS

We randomly assigned 80 cardiac surgery patients to four groups (n = 20 each) without (1) and with three different filtration timing strategies (II-IV). As functional end points neutrophil phagocytic activity and oxidative burst upon ex vivo stimulation with E.coli were analyzed from blood of 31 patients whereas polymorphonuclear elastase (PMNE), myeloperoxidase, and malondialdehyde (MDA), a marker for lipid peroxidation was determined in plasma samples from 80 patients. Blood was harvested immediately before and behind the filter (Pall LG6) at different times during CPB.

RESULTS

We found that none of the filtration strategies either reduced the number of neutrophils capable of eliciting phagocytic activity and oxidative burst or the activity per cell. In contrast, PMNE and MPO levels in peripheral venous blood were found to be significantly increased in groups II-IV compared with group I throughout the entire filtration period in all patients. MDA was not enhanced in the filter groups.

CONCLUSIONS

Our results show that the leukocyte depletion filter in the arterial line of the heart-lung machine failed to limit neutrophil stimulation but rather augmented PMNE plasma levels. We speculate that augmented PMNE and MPO levels mainly stem from neutrophils that are captured within the mesh of the leukocyte filter.

[Positive pressure ventilation in Cheyne-Stokes respiration]

Cheyne-Stokes respiration (CSR) is found in patients with chronic left ventricular failure and associated with a reduced prognosis. Continuous positive airway pressure (CPAP) improves the survival rate. In this retrospective study we report on the effect of different positive pressure ventilation modes in CSR. The observation period lasted from 1995 - 1999. Inclusion criteria was CSR with a respiratory disturbance index > 10/h whereas > 50 % of the events had to be central and/or mixed. In each patient a 4 week lasting intervention with each of CPAP, Bilevel CPAP in spontan mode (i.e. BiPAP S or BiPAP ST) and BiPAP in controlled mode (i.e. BiPAP T) was performed. Responder were defined by subjective and objective criteria. In total 41 males were included. Responder were distributed as follows: CPAP: n = 13 patients (31.7 %), BiPAP S/ST: n = 9 patients (22.0 %) and BiPAP T: n = 12 patients (29.3 %). In total 7 from 41 patients (17.1 %) rejected a long-term treatment with positive pressure ventilation. The majority of patients with CSR responded to CPAP and BiPAP S/ST mode. Compared to the other responder groups the best quality was reached with BiPAP T. However the latter was performed only by 29 % of the population.

Simplified artificial endometrial preparation, using oral estradiol and novel vaginal progesterone tablets: a prospective randomized study

There are various successful protocols for artificial endometrial preparation, comprising induction of endometrial proliferation with estrogens and secretory transformation with progestins. The aim of this prospective randomized study was to evaluate a simplified approach for endometrial preparation, comparing two constant doses of oral estradiol combined with a novel low-dose vaginal natural progesterone preparation (100 mg Endometrin tablets). Twenty-nine patients were enrolled in the study and divided randomly into two groups. Both groups received oral estradiol tablets from the beginning of menstruation, group A (15 patients) receiving 4 mg/day divided into two doses of 2 mg each, and group B (14 patients) receiving 6 mg/day divided into three doses. Serum estradiol and progesterone and sonographic thickness of the endometrium were measured on the 1st day of menstruation and on the 6th, 11th, 16th and 21st days of the artificial cycle. Following the first 12 days of estradiol priming, with an endometrial thickness of > or = 8 mm, Endometrin vaginal tablets 100 mg were added twice a day for 10 days. On the 21st cycle day, an endometrial biopsy was taken from all patients using Pipelle. In all 29 patients, appropriate changes in estradiol, progesterone and endometrial thickness were observed. Estradiol levels were significantly higher in the 6 mg/day group on days 6 and 11, but no significant difference was noted in serum progesterone level and endometrial thickess between groups. Histological evaluation of endometrial biopsies, on the 21st day, revealed adequate late-secretory endometrium in 14/15 (93.3%) patients of group A and in 13/14 (92.9%) patients of group B. In conclusion, our results demonstrate that an appropriate endometrial secretory transformation may be induced using an economical regimen of fixed low-dose oral estradiol (4 mg/day) and low-dose vaginal progesterone tablets (Endometrin 100 mg twice daily).

Interference-free sample preparation for the determination of plasma oxalate analyzed by HPLC-ER: preliminary results from calcium oxalate stone-formers and non-stone-formers

BACKGROUND

Oxalate generation at pH-values above 5.0 and an oxalate-protein binding in acidified plasma would appear to complicate the determination of oxalate in plasma.

METHODS

To avoid complex sample preparation we used a high-performance liquid chromatographic system with an inline enzyme reactor (HPLC-ER) containing immobilised oxalate oxidase. The detection limit was 0.68 micromol/l. Blood was drawn in lithium-heparin vessels and immediately centrifuged at 4 degrees C. The yielded plasma was ultrafiltered using a Centrisart-I-tube. To inhibit oxalate generation by ascorbic acid, the ultrafiltrate was acidified with 1 mol/l hydrochloric acid during ultrafiltration at 4 degrees C. The liquid thus yielded was used for HPLC-ER analysis. Blood samples were obtained from 133 healthy adults (63 men, 70 women, aged 20-94 years) with no history of renal disorder and from 79 patients (53 men, 26 women, aged 19-77 years) with a history of calcium oxalate stone formation.

RESULTS

Mean plasma oxalate was 2.65 +/- 2.31 micromol/l for healthy subjects and 4.21 +/- 0.56 micromol/l for stone formers.

CONCLUSIONS

Analysis yielded no significant differences between males and females. A correlation between age and plasma oxalate was found for the healthy adults (p < 0.001).

Modeling MHC class II molecules and their bound peptides as expressed at the cell surface

A detailed insight to the structure of a given major histocompatibility complex (MHC)-peptide complex can strongly support and also improve the analysis of the peptide binding capabilities of the MHC molecule and the characterization of the developing T cell response. The number of MHC class II-peptide crystal structures is limited, therefore constructing and analyzing computer models can serve as efficient complementary tools when someone deals with experimentally determined binding and/or functional data. Commercial programs are available for modeling protein and protein-protein complexes, in general. However, more accurate results can be obtained if the parameters are directly optimized to a given complex, especially in the case of special proteins as MHC class II, an integral membrane protein, whose functional parts behave like regular globular proteins. Here, we present the optimization of an approach used for modeling MHC class II molecules complexed with various peptides fitting into the binding groove and several ways to analyze them with the help of experimental data.

Differential subcellular localization of the 5-HT3-As receptor subunit in the rat central nervous system

Following the cloning and sequencing of the A subunit of the 5-HT3 receptor, two alternatively spliced isoforms, 5-HT3-AS and 5-HT3-AL, have been identified. In order to analyse the distribution of the receptor, a polyclonal antibody has been produced against the short form which is the most abundant in the central nervous system [Doucet et al. (2000) Neuroscience 95, 881-892]. As expected from the recognition of functional 5-HT3 receptors, immunostaining by this anti-5-HT3-R-AS antibody matched the distribution of the high-affinity 5-HT3 binding sites in the rat brain and spinal cord. 5-HT3-AS-like immunoreactivity was detected at low levels in the limbic system, particularly in the amygdala and the hippocampus, and in the frontal, piriform and entorhinal cortices. High levels of immunoreactivity were found in the brainstem, mainly in the nucleus tractus solitarius and the nucleus of the spinal tract of the trigeminal nerve, and in the dorsal horn of the spinal cord. At the ultrastructural level, immunostaining was generally found associated with axons and nerve terminals (70-80%) except in the hippocampus, where labelled dendrites were more abundant (56%). This preferential localization on nerve endings is consistent with the well-documented physiological role of 5-HT3 receptors in the control of neurotransmitter release. However, the different distribution in the hippocampus raises the question of whether differential addressing mechanisms exist for preferentially targeting 5-HT3 receptors to postsynaptic dendritic sites as compared to presynaptic nerve endings, depending on the nature of the neurons bearing these receptors.

Five-year experience with valve sparing surgery for aortic root aneurysms

BACKGROUND

The aim of this study was to analyze the mid-term results of aortic root reconstruction.

METHODS

Between September 1995 and March 2001, 32 patients (25 males, 7 females, median age 58 +/- 21 years) underwent aortic root reconstruction as described by T. David. Indications for operation were aortic insufficiency with ascending aortic aneurysm in 27 patients, and acute aortic dissection (Stanford type A) in 5 patients. In all patients the native valve was preserved and suspended inside a tubular prosthesis with reimplantation of the coronary arteries. In 10 patients the classic reconstruction technique was modified by shaping a "Neosinus."

RESULTS

There was one perioperative death due to myocardial infarction. Two patients suffered a stroke. 26 patients were followed up 12 months postoperatively. 22 out of 26 patients were in NYHA functional class I, 2 patients in class II and the remaining 2 in class III. Three patients died in the postoperative period. Six patients had trivial AR, 4 mild and 1 moderate regurgitation. There were no thromboembolic events during follow up. The mean transvalvular gradient was 3.5 +/- 2.2 mmHg. Compared to a normal cohort of patients (n = 20), resuspended aortic valves opened (26.4 +/- 5.8 vs. 61.3 +/- 22.1 cm/sec, p < 0.0001) and closed (22.8+/- 6.9 vs. 57.9 +/- 22.3) at a higher speeds and also showed shorter opening (0.053 +/- 0.12 vs. 0.023 +/- 0.09 sec, p < 0.0001) and closing times (0.051 +/- 0.07 vs. 0.23 +/- 0.07 cm/sec) of the aortic leaflets.

CONCLUSIONS

Aortic valve reimplantation is a reliable technique able to reduce long term complications when compared to conventional composite graft replacement of the aortic root. Altered leaflet opening and closing dynamics do not impair midterm durability.

Results and long-term followup of intravenous immunoglobulin infusions in chronic, refractory polymyositis: an open study with thirty-five adult patients

OBJECTIVE

Polymyositis is a rare inflammatory muscular disease of unknown cause. Corticosteroids and immunosuppressive drugs are the first choice of therapy but are not always effective and may cause serious side effects. Many studies have shown that polyvalent intravenous immunoglobulin (IVIG) may be of interest for the treatment of dermatomyositis. We carried out an open, prospective study to evaluate the efficacy of IVIG in subjects with polymyositis that was refractory to traditional treatments, and we evaluated the benefits of this therapy over a long-term period of followup.

METHODS

Thirty-five adult white patients (20 female, 15 male, mean age 43.5 years [SD 16.8]) with chronic, refractory polymyositis were treated with high doses of IVIG, after the patients had received the following traditional treatments: prednisone (n = 35), methotrexate (n = 24), azathioprine (n = 13), cyclophosphamide (n = 4), cyclosporine (n = 7), chlorambucil (n = 1), plasmapheresis (n = 8), lymphopheresis (n = 1), and total body irradiation (n = 1). There had been no changes in the patients' treatment in the 2 months before the initiation of IVIG therapy, and doses were not increased during IVIG treatment. We used preparations of polyvalent human IVIG with increased concentrations of intact IgG. The patients received 1 gm/kg/day for 2 consecutive days per month. The mean course of treatment was 4-6 months. The clinical assessment involved the evaluation of proximal muscle power, muscle disability scale score, and esophageal disorders. The biochemical evaluations carried out before each treatment period were compared by Student's t-test and nonparametric Wilcoxon test. Results were considered to be significant at P = 0.05.

RESULTS

In the short-term, significant clinical improvement was noted in 25 of the 35 patients (71.4%). Mean muscle power was estimated before and after IVIG therapy and was found to be significantly improved (P < 0.01). All patients had a significant biochemical response. Mean creatine kinase levels during IVIG therapy decreased significantly before the fourth IVIG perfusion (P < 0.01). Side effects, usually minor, were noted in 6 patients. This benefit allowed the initial prednisone dose to be reduced by >50% in all patients. The mean (+/- SD) followup time for the 25 patients who responded favorably to IVIG treatment was 51.4 +/- 13.1 months. Twelve of these 25 patients remained in full remission following their initial course of IVIG, resulting in complete stoppage of medication in 5 patients or low doses of steroids in 7 patients. The condition of 6 patients remained improved and no other drugs were prescribed, but the patients remained dependent on IVIG infusions. Seven of the 25 patients who responded well to IVIG treatment relapsed at an average of 17.1 months (range 4-23 months) after the discontinuation of IVIG.

CONCLUSION

IVIG is an interesting therapy for the treatment of polymyositis, with results showing that the condition of approximately 70% of the patients tested improved. After the discontinuation of the IVIG therapy, the efficacy remained stable in 50% of the patients, with a followup of over 3 years.

A high predictive value of the first testicular fine needle aspiration in patients with non-obstructive azoospermia for sperm recovery at the subsequent attempt

BACKGROUND

The objective of this retrospective study, which included 51 men with non-obstructive azoospermia, was to evaluate the predictive value of the results of the first sperm recovery attempt on the probability for sperm recovery in a second attempt.

METHODS AND RESULTS

A positive testicular fine needle aspiration (TEFNA) was defined as the recovery of any number of mature sperm. At the first and second TEFNA attempts, mature sperm were recovered in 33 (64.7%) and 25 (49%) of 51 patients respectively. In 23 of the 33 (69.7%) patients with a positive first TEFNA, sperm were recovered at both attempts, whereas in only two of 18 (11.1%) with a negative first TEFNA, sperm were recovered at the second attempt. Our analysis revealed a high predictive value of the first TEFNA for sperm recovery at the subsequent attempt, with a mean positive predictive value of 69.7%, with the highest probability being 90.9% in hypospermatogenesis, 72.7% in Sertoli cell-only pattern, 75% in tubular hyalinization, and the lowest being 28.6% in maturation arrest. The mean negative predictive value was 88.9%, which was high in all categories (80% in Sertoli cell-only pattern and 100% in maturation arrest and tubular hyalinization).

CONCLUSION

A second TEFNA attempt should be offered to all non-obstructive azoospermic patients with a positive first TEFNA. Patients with a negative first TEFNA may undergo a repeated attempt, but a donor sperm back-up is strongly advised.

Flavonoids: structural requirements for antiproliferative activity on breast cancer cells

Several classes of flavonoids (flavones, flavanones, 2'-hydroxychalcones and flavan-4-ols) having a variety of substituents on A ring were investigated for their antiproliferative activity against MCF-7 human breast cancer cells. Structure-activity relationships of these compounds were discussed. 2'-hydroxychalcones and methoxylated flavanones were found to be potent inhibitors of MCF-7 cells growth whereas flavones and flavan-4-ols appeared to be weak inhibitory agents except 7,8-dihydroxyflavone.

[Metopic craniosynostosis, probable effect of intrauterine exposure to maternal valproate treatment]

Metopic craniosynostosis may be an adverse effect of valproic acid exposed fetus.

CASES

We report two infants with metopic craniosynostosis, born to mothers who were treated with valproic acid. In one case, a prenatal diagnosis was made. In the other case, only the male dizygotic twin was affected.

CONCLUSION

Trigonocephaly may be a symptom of valproate embryofoetopathy detectable by antenatal ultrasound examination.

Gender differences in wall shear-mediated brachial artery vasoconstriction and vasodilation

OBJECTIVES

We sought to investigate wall shear rate (WSR) and brachial artery diameter (BAD) changes simultaneously and to determine whether any gender differences exist in arterial reactivity.

BACKGROUND

Wall shear rate/stress and arterial reactivity are rarely assessed at the same time. Furthermore, flow-mediated vasoconstriction has received less attention than flow-mediated vasodilation in humans.

METHODS

A new noninvasive evaluation of WSR in the brachial artery, using multigated, pulsed Doppler velocimeter and a double-transducer probe moved and fixed by a robotic system, was developed.

RESULTS

The validity of the system was tested in vitro with calibrated tubes and showed a high correlation (r = 0.98, p < 0.001). In 10 men and 10 women of similar age, induction of low and high shear rates by forearm occlusion produced significant vasoconstriction and vasodilation, respectively. The time lag for maximal BAD changes was 3 min for vasoconstriction and 1 min for vasodilation. A greater half-time for vasodilation (96 +/- 6 for men and 86 +/- 12 s for women) than for shear rate (31 +/- 5 s for men and 34 +/- 4 s for women) was observed after discontinuation of occlusion. Relative BAD was correlated with WSR changes, showing a significantly higher slope in women than in men (p < 0.01). Moreover, a larger normalized arterial diameter per shear rate was observed for vasoconstriction (p < 0.01) and vasodilation (p < 0.01) in women than in men.

CONCLUSIONS

Shear-mediated arterial vasodilation and vasoconstriction were more pronounced in women than in men, suggesting different gender-related sensitivity in the regulation of large-artery vascular tone.

Genetic analysis as a valuable key to diagnosis and treatment of periodic Fever

We describe 2 Dutch patients with recurrent fever attacks undiagnosed for more than 40 years. The diagnosis of periodic fever was made when molecular analysis revealed novel mutations in the tumor necrosis factor (TNF) receptor gene (TNFRSF1A), establishing the diagnosis of TNF receptor-associated periodic syndrome. This syndrome is an autosomal dominant disorder characterized by recurring episodes of fever, arthralgia, and skin lesions that is caused by mutations in the 55-kd TNFRSF1A gene. This finding has facilitated treatment for TNF receptor-associated periodic syndrome because blocking of TNF signaling seems to alleviate the symptoms. Use of a short course of recombinant p75TNFR:Fc fusion protein (etanercept) induced prolonged remission in one patient.

Re-occurrence of HIV-1 drug mutations after treatment re-initiation following interruption in patients with multiple treatment failure

Antiretroviral treatment interruption in 20 extensively pre-treated HIV-1 patients with treatment failure led to genotype viral reversion of at least one class of drug-mutation resistance in half of the patients. The only predictive factor of reversion was found to be the duration of interruption. The outgrowth of residual wild-type virus seems not to be a true genetic reversion because drug mutations are detected rapidly at salvage therapy re-initiation.

Myocardial protection by ischemic preconditioning and delta-opioid receptor activation in the isolated working rat heart

OBJECTIVE

delta-Opioid receptors are involved in the cardioprotective effect of ischemic preconditioning. This study was designed (1) to assess the protective capacities of ischemic preconditioning and the synthetic delta-opioid receptor agonist D-Ala(2)-D-Leu(5) enkephalin (DADLE) in a functionally oriented experimental model of ischemia and reperfusion and (2) to assess whether the effects of both protective measures are similarly blocked by naloxone, a nonspecific delta-opioid receptor antagonist.

METHODS

Sixty-four isolated working rat hearts were subjected to 45 minutes of hypothermic ischemia at 30 degrees C followed by 25 minutes of normothermic reperfusion. Rats were pretreated with DADLE (1 mg/kg body weight intravenously), naloxone (3 mg/kg body weight intravenously), or a combination thereof within 60 minutes before onset of isolated heart perfusion. During the preischemic perfusion period, 8 hearts per group were preconditioned by one cycle of 5 minutes of normothermic global ischemia and subsequent reperfusion whereas another 8 served as nonpreconditioned controls. The postischemic functional recovery of hearts and their creatine kinase leakage were determined.

RESULTS

Pretreatment with DADLE and ischemic preconditioning improved the postischemic recovery of aortic flow when compared with nonpreconditioning (57.7% +/- 4.0% and 60.8% +/- 4.3% vs 40.0% +/- 4.2% of preischemic baseline value, P <.001). Combined pretreatment with DADLE before ischemic preconditioning afforded additional aortic flow recovery compared with pretreatment with DADLE alone (68.6% +/- 3.3% vs 57.7% +/- 4.0% of preischemic baseline value; P =.038). With combined pretreatment, early postischemic creatine kinase release was lower than control in hearts without pretreatment (0.48 +/- 0.11 vs 0.80 +/- 0.12 IU/5 minutes per heart; P =.001). Naloxone abolished the beneficial functional effects of pretreatment with DADLE and ischemic preconditioning.

CONCLUSIONS

Pharmacologic activation of delta-opioid receptors affords improvement of functional protection in isolated working rat hearts similar to that conferred by classic ischemic preconditioning. The combination of both pretreatments reduces ischemic cellular damage and further adds to postischemic functional recovery. These changes are reversed by naloxone, an observation providing evidence that ischemic preconditioning involves signaling through opioid receptors.

Resistance profile and cross-resistance of HIV-1 among patients failing a non-nucleoside reverse transcriptase inhibitor-containing regimen

The objectives were to determine the resistance profile and the rate of cross-resistance in HIV-1 infected patients failing an efavirenz or a nevirapine or a nevirapine then efavirenz containing regimens, and to investigate if zidovudine and more generally thymidine analog nucleosides lead to a particular genotypic pattern in nevirapine failing patients. A study was conducted in 104 patients with virological rebound to a non-nucleoside reverse transcriptase inhibitors (NNRTI) regimen (efavirenz n = 39, nevirapine n = 46 and nevirapine then efavirenz n = 19). Genotypic resistance testing was carried out of detectable plasma HIV-1 RNA (> 200 copies/ml). Among the 104 patients studied, only two patients failed to respond to the nevirapine regimen without selection of a NNRTI resistance mutation. All patients failing an efavirenz regimen harboured mutations conferring cross-resistance to nevirapine (K103N, Y188L, G190S). Among patients failing the nevirapine regimen and presenting with NNRTI mutations, 35 (80%) harboured mutations conferring cross-resistance to efavirenz (K101E, K103N, Y188L) and 9 (20%) harboured mutations conferring resistance to nevirapine alone (V106A and Y181C). In patients failing nevirapine then efavirenz therapy, all NNRTI resistance profile led to cross-resistance to all available NNRTIs. Among patients receiving nevirapine, the selection of mutations associated with a cross-resistance to efavirenz was more frequent statistically when a thymidine nucleoside analog (zidovudine or stavudine) was used in the regimen (P = 0.02). In conclusion, 100% of patients developed cross-resistance to nevirapine and efavirenz after treatment by efavirenz and 80% after treatment by nevirapine. The use of a thymidine analog concomitantly with nevirapine leads to the preferential selection of cross-resistance NNRTI mutations.