Determination of resistance at zero and infinite frequencies in bioimpedance spectroscopy for assessment of body composition in babies

OBJECTIVE

Bioimpedance spectroscopy (BIS) is a popular technique for the assessment of body composition in children and adults but has not found extensive use in babies and infants. This due primarily to technical difficulties of measurement in these groups. Although improvements in data modelling have, in part, mitigated this issue, the problem continues to yield unacceptably high rates of poor quality data. This study investigated an alternative data modelling procedure obviating issues associated with BIS measurements in babies and infants. Approach BIS data are conventionally analysed according to the Cole model describing the impedance response of body tissues to an applied AC current. This approach is susceptible to errors due to capacitive leakage errors of measurement at high frequency. The alternative is to model BIS data based on the resistance-frequency spectrum rather than the reactance-resistance Cole model thereby avoiding capacitive error impacts upon reactance measurements. Main results The resistance-frequency approach allowed analysis of 100% of data files obtained from BIS measurements in 72 babies compared to 87% successful analyses with the Cole model. Resistance-frequency modelling error (percentage standard error of the estimate) was half that of the Cole method. Estimated resistances at zero and infinite frequency were used to predict body composition. Resistance-based prediction of fat-free mass (FFM) exhibited a 30% improvement in the two-standard deviation limits of agreement with reference FFM measured by air displacement plethysmography when compared to Cole model-based predictions. Significance This study has demonstrated improvement in the analysis of BIS data based on the resistance frequency response rather than conventional Cole modelling. This approach is recommended for use where BIS data are compromised by high frequency capacitive leakage errors such as those obtained in babies and infants. .

Complete Physical Characterization of Quantum Nondemolition Measurements via Tomography

We introduce a self-consistent tomography for arbitrary quantum nondemolition (QND) detectors. Based on this, we build a complete physical characterization of the detector, including the measurement processes and a quantification of the fidelity, ideality, and backaction of the measurement. This framework is a diagnostic tool for the dynamics of QND detectors, allowing us to identify errors, and to improve their calibration and design. We illustrate this on a realistic Jaynes-Cummings simulation of a superconducting qubit readout. We characterize nondispersive errors, quantify the backaction introduced by the readout cavity, and calibrate the optimal measurement point.

Período de adaptação a dietas com baixa ou alta fibra sobre a digestibilidade e as características fecais em cães

RESUMO Objetivou-se avaliar três períodos de adaptação, cinco, 10 e 15 dias, a dietas com baixa ou alta fibra sobre a digestibilidade e características fecais. Foram utilizadas duas dietas, uma contendo 0% de casca de soja (0%CS) e outra com 15% de casca de soja (15%CS), fornecidas a 12 cães adultos. Ao final de cada período, houve coleta total de fezes para avaliação dos coeficientes de digestibilidade aparente (CDA), energia metabolizável (EM) e características fecais. Além disso, foi avaliada a palatabilidade das dietas. Como resultado, não houve efeito do período de adaptação sobre a digestibilidade das dietas (P>0,05). A dieta 15%CS apresentou menor CDA da matéria seca (MS) e EM, em relação à dieta 0%CS (P<0,05). A consistência fecal dos cães não diferiu entre as dietas e os períodos (P>0,05). Houve redução no pH e na amônia fecal dos cães alimentados com a dieta 15%CS (P<0,05), após 10 dias de alimentação. Não houve diferença na palatabilidade das dietas (P>0,05). Períodos de adaptação à dieta superiores a cinco dias não alteram a digestibilidade e a maioria das características fecais de cães, exceto a amônia fecal. A inclusão de 15%CS na dieta reduz a digestibilidade da MS e a EM, bem como o pH e a amônia fecal.

Strong and frequent T-cell responses to the minor allergen Phl p 12 in Spanish patients IgE-sensitized to Profilins

BACKGROUND

Profilins are dominant pan-allergens known to cause cross-sensitization, leading to clinical symptoms such as pollen-food syndrome. This study aimed to determine the T-cell response to Phl p 12 in profilin-sensitized patients, by measuring the prevalence, strength and cross-reactivity to clinically relevant profilins.

METHODS

The release of Phl p allergens from pollen was determined by mass spectrometry and immunochemistry. T-cell responses, epitope mapping and cross-reactivity to profilins (Phl p 12, Ole e 2, Bet v 2 and Mal d 4) were measured in vitro using PBMCs from 26 Spanish grass-allergic donors IgE-sensitized to profilin. Cross-reactivity was addressed in vivo using 2 different mouse strains (BALB/c and C3H).

RESULTS

Phl p 12 and Phl p 1 are released from pollen simultaneously and in similar amounts. Both T-cell response frequency (17/26 donors) and strength were comparable between Phl p 12 and Phl p 1. T-cell cross-reactivity to other profilins correlated with overall sequence homology, and 2 immunodominant epitope regions of Phl p 12 were identified. Data from mice immunized with Phl p 12 showed that cross-reactivity to Bet v 2 was mediated by conserved epitopes and further influenced by additional genetic factors, likely to be MHC II.

CONCLUSION

The strength, prevalence and cross-reactivity of T-cell responses towards Phl p 12 are comparable to the major allergen Phl p 1, which supports the hypothesis that T cells to Phl p 12 can play an important role in development of allergic symptoms, such as those associated with pollen-food syndrome.

Automated angular and translational tomographic alignment and application to phase-contrast imaging

X-ray computerized tomography (CT) is a 3D imaging technique that makes use of x-ray illumination and image reconstruction techniques to reproduce the internal cross-sections of a sample. Tomographic projection data usually require an initial relative alignment or knowledge of the exact object position and orientation with respect to the detector. As tomographic imaging reaches increasingly better resolution, thermal drifts, mechanical instabilities, and equipment limitations are becoming the main dominant factors contributing to sample positioning uncertainties that will further introduce reconstruction artifacts and limit the attained resolution in the final tomographic reconstruction. Alignment algorithms that require manual interaction impede data analysis with ever-increasing data acquisition rates, supplied by more brilliant sources. We present in this paper an iterative reconstruction algorithm for wrapped phase projection data and an alignment algorithm that automatically takes 5 degrees of freedom, including the possible linear and angular motion errors, into consideration. The presented concepts are applied to simulated and real measured phase-contrast data, exhibiting a possible improvement in the reconstruction resolution. A MATLAB implementation is made publicly available and will allow robust analysis of large volumes of phase-contrast tomography data.

Modified strontium titanates: from defect chemistry to SOFC anodes

A review describing how compositional design of modified strontium titanates can lead to conductive, redox stable SOFC anodes.

[Sentinel node biopsy after neoadjuvant chemotherapy in breast cancer. Its relation with molecular subtypes]

OBJECTIVE

To evaluate the influence of the molecular subtype (MS) in the Sentinel Node Biopsy (SNB) technique after neoadjuvant chemotherapy (NAC) in women with locally advanced breast cancer (BC) and a complete axillary response (CR).

MATERIAL AND METHODS

A prospective study involving 70 patients with BC treated with NAC was carried out. An axillary lymph node dissection was performed in the first 48 patients (validation group: VG), and in case of micro- or macrometastases in the therapeutic application phase (therapy group:TG). Classified according to MS: 14 luminal A; 16 luminal B HER2-, 13 luminal B HER2+, 10HER2+ non-luminal, 17 triple-negative.

RESULTS

SNB was carried out in 98.6% of the cases, with only one false negative result in the VG (FN=2%). Molecular subtype did not affect SN detection. Despite the existence of axillary CR, statistically significant differences were found in the proportion of macrometastasis (16.7% vs. 35.7%, p=0.043) on comparing the pre-NAC cN0 and cN+. Breast tumor response to NAC varied among the different MS, this being lowest in luminal A (21.5%) and highest in non-luminal HER2+ group (80%). HER2+ and triple-negative were the groups with the best axillary histological response both when there was prior clinical involvement and when there was not.

CONCLUSIONS

Molecular subtype is a predictive factor of the degree of tumor response to NAC in breast cancer. However, it does not affect SNB detection and efficiency. SNB can also be used safely in women with prior node involvement as long as a complete clinical and radiological assessment is made of the node response to NAC.

Effects of MSC Coadministration and Route of Delivery on Cord Blood Hematopoietic Stem Cell Engraftment

Hematopoietic stem cell transplantation (HSCT) using umbilical cord blood (UCB) progenitors is increasingly being used. One of the problems that may arise after UCB transplantation is an impaired engraftment. Either intrabone (IB) injection of hematopoietic progenitors or mesenchymal stem cell (MSC) coadministration has been proposed among the strategies to improve engraftment. In the current study, we have assessed the effects of both approaches. Thus, NOD/SCID recipients were transplanted with human UCB CD34+ cells administered either intravenously (IV) or IB, receiving or not bone marrow (BM)-derived MSCs also IV or IB (in the right femur). Human HSC engraftment was measured 3 and 6 weeks after transplantation. Injected MSCs were tracked weekly by bioluminescence. Also, lodgment within the BM niche was assessed at the latter time point by immunofluorescence. Our study shows regarding HSC engraftment that the number of BM human CD45+ cells detected 3 weeks after transplantation was significantly higher in mice cotransplanted with human MSCs. Moreover, these mice had a higher myeloid (CD13+) engraftment and a faster B-cell (CD19+) chimerism. At the late time point evaluated (6 weeks), human engraftment was higher in the group in which both strategies were employed (IB injection of HSC and MSC coadministration). When assessing human MSC administration route, we were able to track MSCs only in the injected femurs, whereas they lost their signal in the contralateral bones. These human MSCs were mainly located around blood vessels in the subendosteal region. In summary, our study shows that MSC coadministration can enhance HSC engraftment in our xenogenic transplantation model, as well as IB administration of the CD34+ cells does. The combination of both strategies seems to be synergistic. Interestingly, MSCs were detected only where they were IB injected contributing to the vascular niche.

[Proximal femoral intramedullary nail versus DHS plate for the treatment of intertrochanteric fractures. A prospective analysis]

OBJECTIVE

To show that patients with intertrochanteric fractures treated with a proximal femoral nail have a better postoperative course than those treated with a DHS plate (dynamic hip screw).

METHODS

Patients with a Boyd & Griffin type II intertrochanteric fracture were randomly divided into two groups: a group of patients treated with a PFN and another one treated with a DHS plate. All patients were assessed at 2, 4, 8 and 16 weeks using the Harris scale and the visual analog scale pre- and postoperatively, as well as the operative time, incision size, intraoperative bleeding, onset of partial and/or total weight bearing, healing time, time to attain prior physical activity level, and radiographic result.

RESULTS

32 patients met our criteria. The variables that had a significant reduction were: incision, operative time, postoperative pain according to the visual analog scale, onset of mobility, partial weight bearing and pain at 2 weeks.

CONCLUSIONS

The proximal femoral nail has better short-term outcomes than the DHS plate; however, in the medium term both implants have the same outcomes.

P3-07-11: Multicenter Comparative Study between One-Step Nucleic Acid Amplification (OSNA) Whole Node Assay and Standard Frozen Section Histology: Intraoperative Molecular Assay for Sentinel Lymph Node Metastases in Early Breast Cancer Can Avoid a Second Surgery

Studies on intraoperative assessment of sentinel nodes by frozen section in breast cancer have reported low sensitivity rates. Recently, a molecular-based procedure to detect lymph node metastases, one-step nucleic acid amplification (OSNA) assay, has been developed. OSNA assay can assess a whole lymph node and yields definitive semi quantitative results. The aim of this study was to evaluate the ability of intraoperative assessment comparing sentinel lymph node (SLN) metastases with OSNA assay versus routine H&E frozen section (FS) histology.

METHODS: A cohort of 478 consecutive patients diagnosed in 2010 with early breast cancer in two centers was analyzed. Frozen section was performed intraoperatively in 228 patients and OSNA assay in 250 patients. Patient characteristics were evaluated in both groups and rates of metastasis detected by both methods were compared.

RESULTS: Patients and tumor characteristic are summarized in the table.

Nanoporous Silica For Low K Dielectrics

As integrated circuit sizes decrease below 0.25 microns, device performance will no longer improve at the same rate as for past generations because of RC interconnect delay which becomes significant as compared to the intrinsic gate delay. Parallel approaches to address this are to use a lower resistance metal (i.e., copper instead of aluminum) and to use a dielectric material with a dielectric constant significantly below that of dense silica (∼4). Recently, considerable progress has been made in development of thin films of nanoporous silica for these applications. Advantages include high thermal stability, small pore size, similarity to conventional spin-on deposition processes and spin-on glass precursors and final material (silica). The dielectric constant of nanoporous silica can be tailored between ∼1 and 3 which allows its’ implementation at multiple technology nodes in integrated circuit manufacture.

Recent development efforts have been focused on; 1) simpler and more reproducible deposition processes, 2) a more complete understanding of processing-property relationships for this material, 3) scale-up of manufacturing to yield a range of precursor products with stability for at least six months and very high purity, and 4) working with customers to integrate this material into both aluminum/gapfill and copper/damascene process flows. This paper targets several specific issues related to nanoporous silica use including water adsorption, pore size distribution control, processing at commercially viable throughputs, and obtaining thickness and dielectric uniformity across 200 mm wafers and wafer to wafer.

Efficacy of silver diamine fluoride for caries reduction in primary teeth and first permanent molars of schoolchildren: 36-month clinical trial

We hypothesized that the six-monthly application of silver diamine fluoride (SDF) can arrest the development of caries in the deciduous dentition of six-year-old schoolchildren and prevent caries in their first permanent molars. A prospective controlled clinical trial was conducted on the efficacy of a 38% SDF solution for caries reduction. Four hundred and twenty-five six-year-old children were divided into two groups: One group received SDF solution in primary canines and molars and first permanent molars every 6 mos for 36 mos. The second group served as controls. The 36-month follow-up was completed by 373 children. The mean number of new decayed surfaces appearing in primary teeth during the study was 0.29 in the SDF group vs. 1.43 in controls. The mean of new decayed surfaces in first permanent molars was 0.37 in the SDF group vs. 1.06 in controls. The SDF solution was found to be effective for caries reduction in primary teeth and first permanent molars in schoolchildren.

Localization and identification of phenolic compounds in Theobroma cacao L. somatic embryogenesis

Cocoa breeders and growers continue to face the problem of high heterogeneity between individuals derived from one progeny. Vegetative propagation by somatic embryogenesis could be a way to increase genetic gains in the field. Somatic embryogenesis in cocoa is difficult and this species is considered as recalcitrant. This study was conducted to investigate the phenolic composition of cocoa flowers (the explants used to achieve somatic embryogenesis) and how it changes during the process, by means of histochemistry and conventional chemical techniques. In flowers, all parts contained polyphenolics but their locations were specific to the organ considered. After placing floral explants in vitro, the polyphenolic content was qualitatively modified and maintained in the calli throughout the culture process. Among the new polyphenolics, the three most abundant were isolated and characterized by 1H- and 13C-NMR. They were hydroxycinnamic acid amides: N-trans-caffeoyl-l-DOPA or clovamide, N-trans-p-coumaroyl-l-tyrosine or deoxiclovamide, and N-trans-caffeoyl-l-tyrosine. The same compounds were found also in fresh, unfermented cocoa beans. The synthesis kinetics for these compounds in calli, under different somatic embryogenesis conditions, revealed a higher concentration under non-embryogenic conditions. Given the antioxidant nature of these compounds, they could reflect the stress status of the tissues.

Processing of ovine cardiac valve allografts: 3. Implantation following antimicrobial treatment and preservation

It is known that a satisfactory clinical outcome can follow the implantation of cardiac valve allografts in spite of the loss of living cells in the tissue. If viable cells are not required for long term graft function, then effective disinfection of the tissue might become possible. In an earlier paper in this series we reported that peracetic acid (PAA) is an effective antimicrobial agent for the treatment of valve allografts; it was lethal to the cells but at a concentration of 0.21% had little effect on the mechanical properties or extracellular morphology of the valve leaflets. It was also found that PAA-treatment could be combined with storage in 85% glycerol at 4 degrees C, or cryopreservation with 10% Me(2)SO, without substantial further impairment of microscopic structure or mechanical properties. In this paper we describe the implantation of processed ovine aortic valves in the descending thoracic aorta of sheep. The experimental groups included control untreated valves and valves that had been treated with antibiotics or PAA and either cryopreserved, or stored in 85% glycerol. The recipient sheep showed good clinical appearances until the experiment was terminated at six months. The explanted grafts were examined by standard morphological and mechanical testing methods. The PAA-treated valves were clearly recognisable as valves: the leaflets had fair to medium morphology in both the unpreserved and the cryopreserved groups. All leaflets had a superficial overgrowth of cells. Microsatellite analysis for allelic differences were performed on samples of donor and recipient tissues using three markers of tissue source. Only one valve, which had been treated with PAA, revealed allelic differences between donor and recipient. It is suggested that DNA-fragments may have remained after the destruction of donor cells and six months of implantation: the overgrowing cells were almost certainly of recipient origin. We conclude that our experiments, in which PAA-treatment was combined with preservation, are sufficiently encouraging to justify further studies to refine the technique, but in our opinion they are not sufficient to justify a clinical trial at this time.

Processing of ovine cardiac valve allografts: 1. Effects of preservation method on structure and mechanical properties

It is essential to have some method of preservation of allograft valves during the time between procurement and implantation. Cryopreservation is the most commonly-used storage method today but it has the major disadvantage of high cost, and because its aim is to preserve living cells only relatively gentle antimicrobial treatments are used. This study addresses two interrelated questions: Is it necessary to maintain living donor cells in the tissue graft? Can more effective measures be used to reduce the risk of transmission of diseases, especially viral diseases, via human tissue grafts. In this paper, we report an investigation of four preservation methods that could be combined with more effective disinfection: cryopreservation with dimethyl sulphoxide, storage at approximately 4 degrees C in a high concentration of glycerol as used for the preservation of skin, snap-freezing by immersion in liquid nitrogen and vitrification. Snap freezing was mechanically damaging and vitrification proved to be impracticable but two methods, cryopreservation and storage in 85% glycerol, were judged worthy of further study. Cryopreservation was shown to maintain cellular viability and excellent microscopic structure with unchanged mechanical properties. The glycerol-preserved valves did not contain any living cells but the connective tissue matrix and mechanical properties were well preserved. The importance of living cells in allograft valves is uncertain. If living cells are unimportant then either method could be combined with more effective disinfection methods: in that case the simplicity and economy of the glycerol method would be advantageous. These questions are addressed in the two later papers in this series.

Processing of cardiac valve allografts: 2. Effects of antimicrobial treatment on sterility, structure and mechanical properties

This is the second in a series of papers that report experiments to investigate the properties required for effective tissue valve implants. This paper is concerned with investigations into alternative antimicrobial treatments and the effect these treatments produce on the structural and biomechanical properties of ovine aortic valves. Six treatments were studied: heat, peracetic acid (at two concentrations), chlorine dioxide, a surfactant cleaning agent and a solvent/detergent treatment. Samples of myocardial tissue were exposed to a mixed bacterial culture or one of three virus cultures and then decontaminated. Two of the six treatments (0.35% peracetic acid and heat) were effective in removing both bacterial and viral contamination, reducing levels of contamination by 2.5 to 3 logs, whilst a third (chlorine dioxide) was effective against viruses ( approximately 3 log reduction). Valves subjected to these treatments were examined by microscopy and measurements of mechanical properties were made. All three treatments seriously damaged endothelial cells and leaflet fibroblasts. Heat treatment also damaged connective tissue components (collagen and elastin) but these changes were not seen after chemical treatment. Mechanical testing confirmed severe damage following heat treatment but chemical treatment showed only minor effects on the elasticity of the leaflets and none on extensibility. These minor effects could be mitigated by exposure to a lower dose of peracetic acid and this treatment could be safely combined with cryopreservation or storage in 85% glycerol. Peracetic acid was the preferred disinfection method for use in the subsequent in vivo studies in sheep.

Repeated administration of hepatitis C virus core-encoding plasmid to mice does not necessarily increase the immune response generated against this antigen

DNA immunization is a promising approach in generating immune responses to infectious pathogens in many different animal models. In an effort to augment the anti-[hepatitis C virus (HCV) core] immune response, generated after DNA immunization, the importance of vaccination regimen regarding dose and boosting was investigated in the present study. Balb/c mice were intramuscularly injected with an expression plasmid encoding a truncated variant comprising amino acids 1-176 of the HCV core protein. The highest anti-core antibody titres (1:3700) were detected in mice inoculated with 50-100 microg of core-encoding plasmid. Additionally, we demonstrated that antibody levels induced by a single injection of DNA could be further increased by boosting with a second injection of DNA three weeks after primary immunization. However, administration of additional doses or lengthening of the resting period between inoculations resulted in similar or even weaker anti-core antibody responses. A similar anti-(HCV core) lymphoproliferative response was also detected in animals that had the highest level of anti-core antibodies. These results indicate that, in clinical trials, vaccination regimen might be a critical factor in generating optimal anti-(HCV core) immune responses after genetic immunization.

Frequency and determinants of microalbuminuria in mild hypertension: a primary-care-based study

OBJECTIVE

To evaluate the frequency of microalbuminuria and its relationship with several risk factors and left ventricular mass in a population of mildly hypertensive subjects attended in a primary-care setting.

DESIGN

Cross-sectional study.

SETTING

Eight primary-care centres.

PATIENTS

Two hundred and twenty-three non-diabetic patients recently diagnosed with mild hypertension were included in the study. None of them had clinical evidence of target-organ damage or had received prior antihypertensive treatment.

INTERVENTIONS

Subjects included in the study underwent clinical interview, measurement of blood pressure (BP) on three visits, blood analysis, measurement of albumin by immunonephelometry in three overnight urine collections, 24 h BP monitoring and M-mode and Doppler echocardiography.

MAIN OUTCOME MEASURES

Tobacco habit, clinic BP, body mass index, serum lipids and uric acid, glycaemia, urinary albumin excretion (UAE), ambulatory BP and left ventricular mass index.

RESULTS

The frequency of microalbuminuria was 7.2%. Microalbuminuric patients were more likely to be men and to be characterized by higher ambulatory BP, body mass index and uric acid levels. Regression analysis demonstrated that male sex and 24 h systolic BP were determinants of UAE. Patients with white-coat hypertension showed lower UAE than did subjects with sustained hypertension. Although a certain relationship between UAE and left ventricular mass index was found, these variables were not significantly correlated.

CONCLUSIONS

A low proportion of mildly hypertensive patients attended in a primary care setting are microalbuminuric. In this population, UAE is an expression of BP values over 24 h and correlates with several risk factors.

Surgery for atrial fibrillation using radiofrequency catheter ablation: assessment of results at one year

OBJECTIVE

The results obtained in 43 patients using direct intraoperative radiofrequency catheter ablation, as an alternative to surgical incisions, to perform atrial fibrillation surgery, are presented.

METHODS

Forty-three patients with ages ranging from 43 to 74 years (x = 59), with chronic atrial fibrillation with an average duration 6+/-5 years were operated. Eleven patients suffered from clinically relevant tachyarrythmia and eight had previous thromboembolic events. All but one patient had concomitant mitral valve surgery. Direct intraoperative radiofrequency catheter ablation was used to perform endocardial bilateral isolation of the pulmonary veins from the left atrium.

RESULTS

There were no local or general complications, namely bleeding or thromboembolic events. Of the 33 patients with more than 3 months of follow-up, 36% remained in atrial fibrillation (Santa Cruz score 0); 30% had Score 4; 18% had Score 3; 6% had Score 2; 9% had Score 1.

CONCLUSIONS

We conclude that the use of intraoperative radiofrequency catheter ablation is fast and safe. Presently, this is our method of choice for surgical treatment of atrial fibrillation in mitral patients.

When and how to report results of surgery on atrial fibrillation

OBJECTIVE

Several medical, interventional and surgical techniques are used to treat atrial fibrillation, aimed at different goals and having variable success rates. To be able to assess and compare all these techniques a methodology of study and a classification is proposed.

METHODS

We developed a five grade score, named the Santa Crus Score, based upon the post-operative atrial rhythm and the effective atrial contraction. Score 0 corresponds to a persistence of atrial fibrillation, the presence of a regular rhythm is grade 1, 2 or 3 if there is no atrial contraction; right atrial contraction; or bilateral atrial contraction, respectively. Score 4 corresponds to sinus rhythm and bilateral atrial contraction. Surgery for atrial fibrillation was performed on 51 patients since 1992. All patients but two had associated mitrial surgery. Three different maze techniques were performed on 17 patients and the pulmonary veins isolation procedure on 34 patients. Patients were reassessed at 1, 6, 12, 24 and 36 months.

RESULTS

After the maze I procedure atrial fibrillation eradication was achieved in 88% of patients but none scored 4. Three patients changed score during the first year. All maze III patients scored 0 initially and one changed to score 3 in the first year. Sixty percent of the maze IIIA patients scored 4, but one evolved to score 0 at 6 months. The pulmonary veins isolation technique eliminated atrial fibrillation in 71% of the patients initially, and in 60% after 1 year, and achieved a score of 4 in a third of the patients.

CONCLUSION

This classification considers the intermediate grades of success that can occur with absence of atrial fibrillation and is applicable to all forms of therapy.

Mechanisms underlying degeneration of cryopreserved vascular homografts

OBJECTIVE

To analyze the mechanism(s) underlying homograft degeneration, we designed an experimental model in which the behavior of cryopreserved autografts and homografts, as well as fresh autografts, implanted in the same animal was compared.

METHODS

A cryopreserved homograft was implanted in the aorta of 14 sheep. The excised aortic autologous segment was then subjected to cryopreservation, and 1 to 8 weeks later it was implanted 1 to 2 cm below the cryopreserved homograft. The intermediate segment of the native aorta, the fresh autograft, was dissected at this point. Animals were put to death at different times and the implanted segments were harvested together with a portion of native aorta. Histologic and immunohistochemical analyses, as well as cell viability assessments, were then performed on the explanted segments. Similar studies were also conducted on fragments of cryopreserved autografts and homografts before implantation.

RESULTS

With the exception of a partial loss of the endothelium, cryopreserved specimens retained cell viability and morphologic integrity before implantation. Explanted cryopreserved homografts showed profound changes affecting all strata, as well as a decline in cell viability. Lymphocyte infiltrates were found up to 12 months after implantation. Endothelium was always absent in cryopreserved homografts. However, a reendothelialization of the cryopreserved autografts was observed. After an initial period of neuronal degeneration, reenervation of the cryopreserved autograft segment occurred 6 to 12 months after the operation. Findings regarding the fresh autografts were similar to those of the cryopreserved autografts.

CONCLUSION

Our results suggest that the immunologic reaction rather than the cryopreservation process is responsible for the degenerative process occurring in cryopreserved homografts.

Purine metabolism in patients with gout: the role of lead

Primary gout is characterized by increased plasma and decreased urinary concentrations of hypoxanthine, xanthine and uric acid. To examine whether lead could explain the disturbance of purine metabolism in gout, we determined hypoxanthine, xanthine and uric acid metabolism and 5-day cumulative urinary lead excretion rates after an EDTA (calcium disodium edetate) test in 27 patients with primary gout and reduced creatinine clearance (C(cr)) and in 50 patients with gout and normal C(cr). The results were compared to those obtained in 26 normal subjects matched for age. All gout patients evidenced a marked renal underexcretion of hypoxanthine, xanthine and uric acid relative to their increased plasma levels. Purine metabolism was remarkably similar in both gout groups except for a significantly lower uric acid excretion in patients with reduced C(cr). Blood lead levels and cumulative lead excretion rates were significantly higher in gout patients with renal failure as compared to patients with normal C(cr). Fourteen patients (52%) with renal insufficiency and 6 (12%) with normal C(cr) showed increased lead excretion rates (95% Cl for the difference, 29-51%, p < 0.001). Mobilizable lead was not significantly correlated with serum or urinary purine concentrations. Hypoxanthine, xanthine and uric acid underexcretion was similar in gout patients with increased or normal cumulative lead excretion rates. The prevalence of atheromatosis and arterial hypertension together was significantly higher in gout patients with renal failure than in patients with normal C(cr) (81 vs. 60%, 95% Cl for the difference, 11-31%, p < 0.005). These results indicate that lead is not a significant contributor to the renal underexcretion of purines in gout. An increased mobilizable lead is not by itself evidence that lead is the cause of the renal insufficiency in patients with primary gout. Atheromatous nephropathy and/or nephroangiosclerosis may explain impaired renal function in patients with primary gout.

Histologic and genetic assessment of explanted allograft valves

A possible way of analyzing the immune response triggered by the allograft and the cellular viability is to compare immunocompetent and immunosuppressed patients, such as those having valve replacement and heart transplantation, respectively. These groups differ in immunosuppression therapy, preparation methods, valve hemodynamics. In the present study, we investigated polymerase chain reaction-amplified DNA flanking hypervariable (CA)n regions obtained from valve leaflets taken from patients having valve replacement or heart transplantation and performed a histologic analyses of the cells. In addition, we assessed an autograft valve to compare the hemodynamic effects on the cellular composition of the valve leaflet. We conclude that leaflet cellularity of the heart transplantation and autograft patients is superior to that of the valve replacement patients. These differences were consistent with the occurrence of an immune response in the valve replacement group, which was prevented or abrogated by immunosuppressive therapy administered to the heart transplantation group. However, it cannot be excluded that preparation procedures have a long-term effect on the extracellular matrix, leading to deterioration of cell adhesion and homing conditions.

Expression of antigens of the carcinoembryonic antigen family on B cell lymphomas and Epstein-Barr virus immortalized B cell lines

Expression of antigens of the carcinoembryonic (CEA) family on B cell lymphomas and Epstein-Barr virus (EBV) immortalized B cell lines was studied using two CEA reactive mAbs. Results from experiments where five B cell lymphomas and two immortalized B cell lines, one from fetal liver and one from normal blood, were analyzed by flow cytometry, showed that all cell lines were strongly reactive with both mAbs. Glycoproteins of 66-90 kDa were identified in cell lysates and spent medium of metabolically labelled cells, immunoprecipitated with the two anti-CEA mAbs and analyzed by SDS-PAGE autoradiography. In cell lysates, a polyclonal anti-CEA antibody reacted with two molecules of 78 and 90 kDa. EBV negative lymphomas, converted, in vitro, with EBV, expressed significantly higher glycoprotein levels, as compared with the parent cell lines. Furthermore, two additional glycoproteins of 45 and 33 kDa were found in lysates from these cells. Northern analysis of mRNA from four of the lymphoma and one of the EBV immortalized B cell lines, using a probe which hybridizes with all CEA family members, showed two CEA related transcripts of 3.9 and 2.2 kb. Based on the sizes of the transcripts and of the glycoproteins, it was concluded that some of the CEA antigens expressed on B cells were, most likely, alternatively spliced forms of biliary glycoprotein.

Interleukin 5 is a differentiation factor for cytotoxic T lymphocytes

The role of IL-5 on the generation of cytotoxic T lymphocytes (CTL) was analysed using a culture system in which production of T helper cell factors was abrogated by exposure of the stimulator cells to ultraviolet irradiation. Supernatants from a T helper cell line (2.19 sup), recombinant (r) IL-2, rIL-4 and rIL-5 were then tested for the capacity to replace T cell help, on the generation of CTL. The results showed that the specific CTL response, in unseparated spleen cells, could be reconstituted by either 2.19 sup, IL-2 or IL-4. However, if the responder cells were purified in nylon wool, only 2.19 sup or rIL-4 plus rIL-5, but not each lymphokine per se, reconstituted the CTL response. Because IL-5 does not support T cell proliferation, it is suggested that IL-5 induces differentiation of immature precursors into CTL. Based on these findings and in an attempt to conciliate the conflicting views that have emerged from different reports, as to whether IL-2 by itself could support generation of CTL in purified T cells, a hypothesis is formulated, suggesting that T cell at different stages of differentiation require distinct lymphokines to acquire CTL effector function.

Biosynthesis of phenolic compounds inVitis vinifera cell suspension cultures: Study on hydroxycinnamoyl CoA:ligase

In cell suspensions cultures from grape berry pulp (Vitis vinifera cv. Gamay fréaux)hydroxycinnamoyl CoA ligase (CoAL) displayed maximum activity (100 %) forp-coumaric acid and then, in decreasing order, for ferulic acid (81.3 %) and caffeic acid (60.4 %). No activity was detected with sinapic and cinnamic acids. The changes in CoAL activity during the growth cycle of the culture displayed two peaks : the highest (6 h after subculturing) was linked with a strong increase in protein caused by dilution ; the second was weaker and occurred on the 7th day of culture.Grape cell suspension accumulated mainly peonidin (Pn) and cyanidin (Cy) glucosides (Pn 3-glucoside, Cy 3-glucoside, Pn 3-acetylglucoside, Pn 3-caffeylglucoside, Pn 3-p-coumarylglucoside, and Cy 3-p-coumarylglucoside). Maximum accumulation of anthocyanins was associated with the exponential growth phase of the culture and might be the result of the substantial increase in CoAL activity resulting from the effect of dilution. The second enzyme activity peak was probably oriented towards the acylation of anthocyanins since the percentage of acylated forms increased with time after subculturing.

Acute adrenal insufficiency mimicking septic shock: a case report

Acute adrenal insufficiency is an unusual problem that may mimic overwhelming sepsis. Elevated cardiac output and low systemic vascular resistance in a patient with known risk factors should alert clinicians to the possibility of that condition.

Sex differences in uric acid metabolism in adults: evidence for a lack of influence of estradiol-17 beta (E2) on the renal handling of urate

The serum urate concentration of adult women, which is lower than in men of a similar age, is thought to be related to a higher renal clearance of urate in women, possibly due to their higher plasma estrogen levels. Intersexual differences in the renal handling of uric acid was assessed in 9 normal adult women and 9 normal age-matched men. Women showed a significantly lower serum urate concentration as compared to men (3.5 +/- 0.3 v 4.9 +/- 0.7 mg/dL, P less than 0.001), higher fractional excretion of urate (9.8 +/- 1.0 v 7.3 +/- 0.8%, P less than 0.001), and significantly lower tubular urate postsecretory reabsorption (67.2 +/- 1.6 v 76.6 +/- 1.4% of secreted urate, P less than 0.01). To test whether plasma E2 has a uricosuric effect we administered estradiol valerate and estradiol benzoate to either oophorectomized or adult women. Plasma E2 levels and urinary total estrogen excretion increased significantly in both groups but the treatment failed to significantly modify serum urate or the fractional excretion of uric acid. Furthermore, in 4 normal adult women, the tubular phases that modulate the renal excretion of urate were not significantly influenced by increased plasma E2 levels. We conclude that in comparison to men of a similar age, the lower tubular urate postsecretory reabsorption of adult women is in accordance with the intersexual differences in uric acid metabolism. Plasma E2 does not influence renal handling of uric acid or serum urate levels.

Renal handling of uric acid in patients with recurrent calcium nephrolithiasis and hyperuricosuria

Hyperuricosuria is a frequent finding in patients with recurrent calcium nephrolithiasis (RCN) that has been related to purine overingestion . The influence of diet and the renal handling of uric acid were investigated in patients with RCN to assess the pathogenic mechanism of excessive urate excretion. Among 50 patients with recurrent nephrolithiasis 42 formed renal stones containing calcium and 9 of these 42 patients demonstrated concomitant asymptomatic hyperuricosuria while on a self-selected diet. Ingestion of a purine-free diet normalized the uric acid excretion in 4 of these 9 patients. The other 5 patients showed persistent hyperuricosuria while on a purine-free diet. In order to assess a possible dysfunction in the renal handling of uric acid, pharmacological tests were undertaken in these 9 patients. Pyrazinamide administration almost completely suppressed urate excretion, excluding a presecretory reabsorption defect. Urate excretion in response to probenecid administration was decreased in 4 patients and increased in 1. This finding is in accordance with a postsecretory reabsorption defect in the former and an augmented tubular secretion of urate in the latter. This study proves that both dietary factors and tubular transport defects are involved in patients with recurrent calcium nephrolithiasis and hyperuricosuria.