Nurses' preferences regarding MenACWY conjugate vaccines attributes: a discrete choice experiment in Spain.

OBJECTIVES: Immunisation against preventable diseases as meningitis is crucial from a public health perspective to face challenges posed by these infections. Nurses hold a great responsibility for these programs, which highlights the importance of understanding their preferences and needs to improve the success of campaigns. This study aimed to investigate nurses' preferences regarding Meningococcus A, C, W, and Y (MenACWY) conjugate vaccines commercialised in Spain. STUDY DESIGN: A national-level discrete choice experiment (DCE) was conducted. METHODS: A literature review and a focus group informed the DCE design. Six attributes were included: pharmaceutical form, coadministration evidence, shelf-life, package contents, single-doses per package, and package volume. Conditional logit models quantified preferences and relative importance (RI). RESULTS: Thirty experienced primary care nurses participated in this study. Evidence of coadministration with other vaccines was the most important attribute (RI = 43.78%), followed by package size (RI = 22.17%), pharmaceutical form (RI = 19.07%), and package content (RI = 11.80%). There was a preference for evidence of coadministration with routine vaccines (odds ratio [OR] = 2.579, 95% confidence interval [95%CI] = 2.210-3.002), smaller volumes (OR = 1.494, 95%CI = 1.264-1.767), liquid formulations (OR = 1.283, 95%CI = 1.108-1.486) and package contents including only vial/s (OR = 1.283, 95%CI = 1.108-1.486). No statistical evidence was found for the remaining attributes. CONCLUSIONS: Evidence of coadministration with routine vaccines, easy-to-store packages, and fully liquid formulations were drivers of nurses' preferences regarding MenACWY conjugate vaccines. These findings provide valuable insights for decision-makers to optimize current campaigns.

Clinical and economic hospital burden of acute respiratory infection (BARI) due to respiratory syncytial virus in Spanish children, 2015-2018.

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory infection (ALRI) in children, causing frequent outpatient visits and hospitalizations. Our study aimed to describe the clinical and direct economic burden of ALRI hospitalizations related to RSV in children in Spain and the characteristics of patients and their episodes. In this retrospective study, ALRI hospitalizations in children aged < 5 years for 2015-2018 were reviewed using anonymized administrative public hospital discharge data from Spain. Three case definitions were considered: (a) RSV-specific; (b) RSV-specific and unspecified acute bronchiolitis (RSV-specific and bronchiolitis); and (c) RSV-specific and unspecified ALRI (RSV-specific and ALRI). The study reported a mean of 36,743 yearly admissions potentially due to RSV, resulting in a mean annual cost of €87.1 million. RSV-specific codes accounted for 39.2% of cases, unspecified acute bronchiolitis for 20.1%, and other unspecified ALRI codes for the remaining 40.6%. The mean hospitalization rate per 1,000 children was 55.5 in the first year of life, 16.0 in the second, and 5.4 between 24 and 59 months. A considerable proportion of cases occurred in children under two years old (> 80.4%) and even during the first year of life (> 61.7%). Otherwise healthy children accounted for 92.9% of hospitalizations and 83.3% of costs during the period. Children born preterm accounted for 1.3% of hospitalizations and 5.7% of costs. The findings revealed that RSV still contributes to a high burden on the Spanish health care system. Children under one year of age and otherwise healthy term infants accounted for most of the substantial clinical and economic burden of RSV. Current evidence potentially underestimates the true epidemiology and burden of severe RSV infection; thus, further studies focusing on the outpatient setting are needed.

Excess hospitalizations and mortality associated with seasonal influenza in Spain, 2008-2018.

BACKGROUND: Influenza may trigger complications, particularly in at-risk groups, potentially leading to hospitalization or death. However, due to lack of routine testing, influenza cases are infrequently coded with influenza-specific diagnosis. Statistical models using influenza activity as an explanatory variable can be used to estimate annual hospitalizations and deaths associated with influenza. Our study aimed to estimate the clinical and economic burden of severe influenza in Spain, considering such models. METHODS: The study comprised ten epidemic seasons (2008/2009-2017/2018) and used two approaches: (i) a direct method of estimating the seasonal influenza hospitalization, based on the number of National Health Service hospitalizations with influenza-specific International Classification of Diseases (ICD) codes (ICD-9: 487-488; ICD-10: J09-J11), as primary or secondary diagnosis; (ii) an indirect method of estimating excess hospitalizations and deaths using broader groups of ICD codes in time-series models, computed for six age groups and four groups of diagnoses: pneumonia or influenza (ICD-9: 480-488, 517.1; ICD-10: J09-J18), respiratory (ICD-9: 460-519; ICD-10: J00-J99), respiratory or cardiovascular (C&R, ICD-9: 390-459, 460-519; ICD-10: I00-I99, J00-J99), and all-cause. Means, excluding the H1N1pdm09 pandemic (2009/2010), are reported in this study. RESULTS: The mean number of hospitalizations with a diagnosis of influenza per season was 13,063, corresponding to 28.1 cases per 100,000 people. The mean direct annual cost of these hospitalizations was €45.7 million, of which 65.7% was generated by patients with comorbidities. Mean annual influenza-associated C&R hospitalizations were estimated at 34,894 (min: 16,546; max: 52,861), corresponding to 75.0 cases per 100,000 (95% confidence interval [CI]: 63.3-86.3) for all ages and 335.3 (95% CI: 293.2-377.5) in patients aged ≥ 65 years. We estimate 3.8 influenza-associated excess C&R hospitalizations for each hospitalization coded with an influenza-specific diagnosis in patients aged ≥ 65 years. The mean direct annual cost of the estimated excess C&R hospitalizations was €142.9 million for all ages and €115.9 million for patients aged ≥ 65 years. Mean annual influenza-associated all-cause mortality per 100,000 people was estimated at 27.7 for all ages. CONCLUSIONS: Results suggest a relevant under-detected burden of influenza mostly in the elderly population, but not neglectable in younger people.

PM2.5 elemental composition in indoor residential environments and co-exposure effects on respiratory health in an industrial area.

This study aimed to identify and characterise indoor sources of particulate matter (PM) in domestic environments. 74 inhabited apartments located in the urban area of Gela (Sicily, Italy), close to a refinery, and in three villages of the hinterland were evaluated, in real-world conditions, for the elemental composition of PM2.5. The samples were collected simultaneously inside and outside each apartment for 48 h. In addition, two of the apartments were simultaneously studied for four weeks. The elemental composition of PM2.5 was determined by applying a chemical fractionation procedure followed by inductively-coupled plasma spectrometry analysis, with both optical emission and mass detection. The extractable, more bio-accessible fraction (ext), and the mineralised residual fraction (res) of each element were determined, thus increasing the selectivity of elements as source tracers. Indoor air in the considered apartments was affected by both outdoor pollution and specific indoor emission sources. The behaviour of each source was studied in detail, identifying a reliable tracer: Tires for soil, Asext for industrial sources, Vext for heavy oil combustion, Ce for cigarette smoking and Mo for the use of vacuum dust cleaners. Asext and Vext showed an excellent infiltration capacity, while the concentration of Tires was affected by a low infiltration capacity and by the contribution of particles re-suspension caused by the residents' movements. In the case of Ce and Mo, indoor concentrations were much higher than outdoor with a high variability among the apartments, due to the inhabitants' habits concerning cigarette smoke and use of electric appliances. To test the overall effect of the concomitant exposure to the identified sources on Wh12 M and on DDA, a WQS analysis was conducted. Cigarette smoking and heavily oil combustion driven the Wh12 M odds increase, while the DDA odds increase was mainly driven by heavily oil combustion and the use of vacuum dust cleaners.

Clinical and economic burden of respiratory syncytial virus in Spanish children: the BARI study.

Respiratory syncytial virus (RSV) infection is a major cause of morbidity in children. However, its disease burden remains poorly understood, particularly outside of the hospital setting. Our study aimed to estimate the burden of medically attended acute lower respiratory infection (ALRI) cases potentially related to RSV in Spanish children. Longitudinal data from September 2017 to June 2018 of 51,292 children aged < 5 years old from the National Healthcare System (NHS) of two Spanish regions were used. Three case definitions were considered: (a) RSV-specific; (b) RSV-specific and unspecified acute bronchiolitis (RSV-specific and Bronchiolitis), and; (c) RSV-specific and unspecified ALRI (RSV-specific and ALRI). A total of 3460 medically attended ALRI cases potentially due to RSV were identified, of which 257 (7.4%), 164 (4.7%), and 3039 (87.8%) coded with RSV-specific, unspecific bronchiolitis, and unspecific ALRI codes, respectively. Medically attended RSV-specific and ALRI cases per 1000 children was 134.4 in the first year of life, 119.4 in the second, and 35.3 between 2 and 5 years old. Most cases were observed in otherwise healthy children (93.1%). Mean direct healthcare cost per medically attended RSV-specific and ALRI case was €1753 in the first year of life, €896 in the second, and €683 between 2 and 5 years old. Hospitalization was the main driver of these costs, accounting for 55.6%, 38.0% and 33.4%, in each respective age group. In RSV-specific cases, mean direct healthcare cost per medically attended case was higher, mostly due to hospitalization: €3362 in the first year of life (72.9% from hospitalizations), €3252 in the second (72.1%), and €3514 between 2 and 5 years old (74.2%). These findings suggest that hospitalization data alone will underestimate the RSV infections requiring medical care, as will relying only on RSV-specific codes. RSV testing and codification must be improved and preventive solutions adopted, to protect all infants, particularly during the first year of life.

Humeral metastasis of renal cancer: Surgical options and review of literature.

INTRODUCTION: The humerus is the second most common long bone site of metastatic disease from renal cell carcinomas (RCC) after femur. Surgery has an important role in the treatment of these lesions due to renal cell tumor's resistance to chemotherapy and radiotherapy. HYPOTHESIS: Prosthetic replacement is an effective and safe solution in treatment of renal humeral metastasis. MATERIAL AND METHODS: Fifty-six patients affected by RCC bone metastases of the humerus that underwent a surgical reconstruction were rewised. Thirty-five lesions were localized on proximal third, 12 on the shaft, 9 on distal third. Among proximal 29 were treated with resection and endoprosthetic replacement and 6 with plate and cement. Six diaphyseal lesions were stabilized with intramedullary nailing, 5 with plate and cement and 1 with an intercalary prosthesis. Regarding distal lesions, 7 elbow prostheses and 2 plates and cement were used. RESULTS: The average age was 63years. Metastasis was single in 55% of cases, and in 45% metachronous. A pathologic fracture (PF) occurred in 64% of cases. Only 9% of patients had a mechanical complication, 7% an infection and 5% neurological deficit. A local recurrence occurred in 14% of patients. An implant failure has been observed in 10 patients, 5 for mechanical complications, 2 for infections and 3 for local recurrence; of these 7 were treated with a prosthesis and 3 with plate and cement. The mean value of MSTS score was 64%, 63% and 59% respectively in patients with proximal, diaphyseal and distal humerus metastases. DISCUSSION: Solitary and metachronous bone metastases have a longer survival. Disease-free interval>2years is another important prognostic factor. Reconstruction with a modular prosthesis is recommended in proximal and distal third. Instead in diaphyseal lesions a closed reduction and fixation with intramedullary locked nailing are preferred. When surgical indications are correctly followed, good oncologic and functional outcomes are obtained, leading to markedly improvement of patients' quality of life. RETROSPECTIVE STUDY: Level of evidence: IV.

Extra-axial chordoma: a clinicopathologic analysis of six cases.

Extra-axial chordoma is an exceedingly rare tumor, with only 28 cases reported in the literature to date. Axial and extra-axial chordoma exhibits complete morphologic and immunophenotypic (expression of brachyury) overlap. However, in consideration of the non-canonical presentation, extra-axial chordoma is under-recognized and often misdiagnosed, most often as extraskeletal myxoid chondrosarcoma or myoepithelioma. To increase our understanding of the clinicopathologic features of extra-axial chordoma, six cases have been retrieved from the files of the Istituto Ortopedico Rizzoli and of the General Hospital of Treviso. The clinicoradiologic, morphologic, and molecular features have been analyzed, and the follow-up was updated. Our series included four female and two male patients; their ages ranged from 20 to 67 years (mean 45.8 years). All patients presented with a single mass localized in four cases in the soft tissue (posterior arm, left leg, dorsal aspect of the foot, and popliteal fossa), and in two cases in the bone (radius and second metacarpal bone). Grossly, the neoplasm was lobulated, with a fleshy cut surface and a diameter ranging between 0.8 and 8 cm (mean 3.4 cm). Morphologically, all six cases showed an epithelioid cell proliferation organized in nests and cords demarcated by fibrous septa and set in an abundant extracellular myxoid matrix. Neoplastic cells featured hyperchromatic nuclei and abundant vacuolated cytoplasm. Immunohistochemically, all six cases were strongly positive for EMA, cytokeratin AE1/AE3, S100, and brachyury. INI1 nuclear expression was retained. Smooth muscle actin, calponin, p63, and GFAP were all negative. Fluorescent in situ hybridization (FISH) analysis did not reveal rearrangements involving NR4A3, FUS, and EWSR1 genes. At follow-up (mean 55 months), all patients were alive without disease after local surgical treatment. One patient underwent thigh amputation following multiple local recurrences and inguinal node metastases treated with marginal resection. In conclusion, primary extra-axial chordoma is an extremely rare neoplasm with distinct morphological and immunohistochemical features. Immunomorphology and molecular analysis allow distinction from both extraskeletal myxoid chondrosarcoma and myoepithelioma. Complete surgical resection appears to be curative.

Childhood osteosarcoma: Incidence and survival in Argentina. Report from the National Pediatric Cancer Registry, ROHA Network 2000-2013.

BACKGROUND: Differences in incidence and survival in osteosarcoma reports are considerable worldwide. PURPOSE: This study describes the incidence and survival of patients with osteosarcoma in Argentina with data from the National Pediatric Cancer Registry (ROHA), and the impact of age, gender, stage, regional, and socioeconomic indicators on outcome. METHODS: Pediatric patients with osteosarcoma reported to ROHA from 2000 through 2013 were analyzed, the annual age-standardized incidence rate (ASR) was calculated using the National Vital Statistics, and survival was estimated. The extended human development index (EHDI) for each reporting region was used as an indicator of socioeconomic status. RESULTS: There were 515 cases of osteosarcoma identified, yielding an ASR of 3.2/1,000,000 children (0-14 years old). The ASR did not vary significantly by year of diagnosis but ranged from 4.0/1,000,000 in the Cuyo/Western Central region to 2.7/1,000,000 in the northeast region (P < 0.000). The estimated 5-year survival rate was 45% (95% confidence interval [CI] 44-51%), with no difference by sex, diagnosis year, region, or EHDI score (P > 0.1 in all cases). Survival rate for localized disease was 52% (95% CI 45-57%) and for metastatic 22% (95% CI 15-30%). CONCLUSIONS: In Argentina, ASR of osteosarcoma is similar to that in high-income countries, but survival is lower in all regions. Future work will focus on identification and reduction of causes of preventable treatment failure.

SIgA response and incidence of upper respiratory tract infections during intensified training in youth basketball players.

The aim of the present study was to examine the effect of an intensified training phase followed by a tapering phase on the salivary immunoglobulin A concentration and on the upper respiratory tract infection (URTI) symptoms in young male basketball players. The session rating of perceived exertion method was used to quantify the internal training load, and the Wisconsin Upper Respiratory Symptom Survey-21 questionnaire was used to assess URTI symptoms. The Yo-Yo IR1 test and saliva collection were carried out at the beginning of the study (T1), after the intensified phase (T2), and after tapering (T3). A higher internal training load was observed for the intensified phase compared with the tapering phase (t=19.10; p<0.001), and a significant decrease in salivary immunoglobulin A concentration was detected (F=7.48; p=0.004) at T3 compared to T1 (p=0.02) and T2 (p=0.05). However, there was no significant difference between phases for severity of URTI (χ2= 2.83; p=0.242). The Yo-Yo IR1 test performance increased from T2 and T3 compared to T1 (F=58.24; p<0.001). There was no significant effect of aerobic fitness level on salivary immunoglobulin A response (F=1.095; p=0.344). In summary, the present findings suggest that an intensified training load followed by a tapering period negatively affects the mucosal immune function with no significant change in severity of URTI in young basketball players.

Total elbow arthroplasty for primary and metastatic tumor.

BACKGROUND: Prostheses can be used in elbow reconstruction in both primary and metastatic lesions. Several authors have reported their experience with different types of implant, but not with modular prostheses. HYPOTHESIS: Limb salvage using an elbow prosthesis is effective in obtaining good functional results and reliable local tumor control. MATERIAL AND METHODS: Forty-seven patients treated at the Rizzoli Institute for elbow neoplasm from 1990 to 2012 were evaluated. There were 30 primary tumors (64%), 24 bone tumors and 6 soft tissue sarcomas, and 17 bone metastases. Elbow reconstruction used a modular prosthesis in 25 patients and a standard prosthesis in 22. Reconstruction was primary in 30 patients and secondary in 17. RESULTS: At last control, 15 (32%) were dead of disease (DOD) at a mean follow-up of 35 months, 12 (25%) were alive with disease (AWD) at a mean follow-up of 29 months, 19 (40%) showed no evidence of disease (NED) at a mean follow-up of 80 months. Early complications were related to unexpected neurological damage, observed in 12 patients (25%): in 5 cases the deficit resolved in a mean 6 months; in the others, no or only partial recovery was observed. Two implants (4%) developed infection: 1 was treated with antibiotic therapy, and the other required implant revision. One implant showing cement extrusion was revised. In 3 patients (6%) radiography showed a radiolucent halo around the stem (2 humeral, 1 ulnar); no measures were taken, as the patients were completely asymptomatic at every follow-up. In 3 patients (6%) partial resorption of the allograft was observed on X-ray, but remained unchanged at last follow-up, without pain or functional impairment. Seven local recurrences (15%) were observed, at a mean of 16 months after surgery; 5 were treated by resection and/or radiotherapy, and 2 by amputation. Mean functional scores on MEPS and MSTS were respectively 84% and 22/30 (73%). CONCLUSIONS: Elbow prostheses provided better function in primary than in metastatic tumor. Elbow prosthesis reconstruction after tumor resection is a viable option both for primary and secondary bone neoplasms. TYPE OF STUDY: Therapeutic. LEVEL OF EVIDENCE: IV, retrospective study.

Microfabricated glucose biosensor for culture well operation.

A water-based carbon screen-printing ink formulation, containing the redox mediator cobalt phthalocyanine (CoPC) and the enzyme glucose oxidase (GOx), was investigated for its suitability to fabricate glucose microbiosensors in a 96-well microplate format: (1) the biosensor ink was dip-coated onto a platinum (Pt) wire electrode, leading to satisfactory amperometric performance; (2) the ink was deposited onto the surface of a series of Pt microelectrodes (10-500 µm diameter) fabricated on a silicon substrate using MEMS (microelectromechanical systems) microfabrication techniques: capillary deposition proved to be successful; a Pt microdisc electrode of ≥100 µm was required for optimum biosensor performance; (3) MEMS processing was used to fabricate suitably sized metal (Pt) tracks and pads onto a silicon 96 well format base chip, and the glucose biosensor ink was screen-printed onto these pads to create glucose microbiosensors. When formed into microwells, using a 340 µl volume of buffer, the microbiosensors produced steady-state amperometric responses which showed linearity up to 5 mM glucose (CV=6% for n=5 biosensors). When coated, using an optimised protocol, with collagen in order to aid cell adhesion, the biosensors continued to show satisfactory performance in culture medium (linear range to 2 mM, dynamic range to 7 mM, CV=5.7% for n=4 biosensors). Finally, the operation of these collagen-coated microbiosensors, in 5-well 96-well format microwells, was tested using a 5-channel multipotentiostat. A relationship between amperometric response due to glucose, and cell number in the microwells, was observed. These results indicate that microphotolithography and screen-printing techniques can be combined successfully to produce microbiosensors capable of monitoring glucose metabolism in 96 well format cell cultures. The potential application areas for these microbiosensors are discussed.

Salivary IL-21 and IgA responses to a competitive match in elite basketball players.

Athletes engaged in strenuous training might experience transient immune suppression that could lead to greater incidence of upper respiratory tract infections (URTI). Since interleukin 21 (IL-21) stimulates immunoglobulin A (IgA) secreting cells and a low level of this immunoglobulin is associated with increased incidence of URTI, the aim of the present study was to investigate the effect of a basketball match on salivary cortisol (sC), salivary IL-21 (sIL-21) and salivary IgA (sIgA) levels. Twenty male basketball players participated in an official game in two teams (10 players in each team). The saliva samples were collected before the warm-up and approximately 10-15 min after the end of the match and were analysed by ELISA methods. sC concentration increased significantly after the match while sIL-21 level was reduced (p < 0.05). In opposition to the study's hypothesis, sIgA level did not change in response to the match. The present findings suggest that a basketball match is sufficiently stressful to elevate sC concentration and attenuates the sIL-21 output without compromising the sIgA level. It is reasonable to speculate that the stability of sIgA acute responses to the match, despite the decrement in sIL-21, indicates that other mechanisms rather than IL-21 stimulating B cell proliferation/differentiation might modulate IgA concentration and secretion rate.

Preliminary report on a catalyst derived from induced cells of Rhodococcus rhodochrous strain DAP 96253 that delays the ripening of selected climacteric fruit: bananas, avocados, and peaches.

Despite the use of refrigeration, improved packaging, adsorbents, and ethylene receptor blockers, on average, nearly 40% of all fruits and vegetables harvested in the US are not consumed. Many plant products, especially fruit, continue to ripen after harvesting, and as they do so, become increasingly susceptible to mechanical injury, resulting in increased rot. Other plant products during transportation and storage are susceptible to chill injury (CI). There is a real need for products that can delay ripening or mitigate the effects of CI, yet still permit full ripeness and quality to be achieved. Preliminary results are discussed where catalyst derived from cells of Rhodococcus rhodochrous DAP 96253, grown under conditions that induced high levels of nitrile hydratase, were able to extend the ripening and thus the shelf-life of selected climacteric fruits (banana, avocado, and peach). A catalyst, when placed in proximity to, but not touching, the test fruit delayed the ripening but did not alter the final ripeness of the fruit tested. Organoleptic evaluations conducted with control peaches and with peaches exposed to, but not in contact with, the catalyst showed that the catalyst-treated peaches achieved full, natural levels of ripeness with respect to aroma, flavor, sweetness, and juice content. Furthermore, the results of delayed ripening were achieved at ambient temperatures (without the need for refrigeration).

A screen-printed microband glucose biosensor system for real-time monitoring of toxicity in cell culture.

Microband biosensors, screen-printed from a water-based carbon ink containing cobalt phthalocyanine redox mediator and glucose oxidase (GOD) enzyme, were used to monitor glucose levels continuously in buffer and culture medium. Five biosensors were operated amperometrically (E(app) of +0.4V), in a 12-well tissue culture plate system at 37°C, using a multipotentiostat. After 24 h, a linear calibration plot was obtained from steady-state current responses for glucose concentrations up to 10 mM (dynamic range 30 mM). Within the linear region, a correlation coefficient (R(2)) of 0.981 was obtained between biosensor and spectrophotometric assays. Over 24 h, an estimated 0.15% (89 nmol) of the starting glucose concentration (24 mM) was consumed by the microbiosensor. The sensitivity of the biosensor response in full culture medium was stable between pHs 7.3 and 8.4. Amperometric responses for HepG2 monolayer cultures decreased with time in inverse proportionality to cell number (for 0 to 10(6) cell/ml), as glucose was being metabolised. HepG2 3D cultures (spheroids) were also shown to metabolise glucose, at a rate which was independent of spheroid age (between 6 and 15 days). Spheroids were used to assay the effect of a typical hepatotoxin, paracetamol. At 1 mM paracetamol, glucose uptake was inhibited by 95% after 6 h in culture; at 500 µM, around 15% inhibition was observed after 16 h. This microband biosensor culture system could form the basis for an in vitro toxicity testing system.

Amperometric lactate biosensor for flow injection analysis based on a screen-printed carbon electrode containing Meldola's Blue-Reinecke salt, coated with lactate dehydrogenase and NAD+.

A biosensor for the measurement of lactate in serum has been developed, which is based on a screen-printed carbon electrode, modified with Meldola's Blue-Reinecke Salt (MBRS-SPCE), coated with the enzyme lactate dehydrogenase NAD(+) dependent (from Porcine heart), and NAD(+). A cellulose acetate layer was deposited on the top of the device to act as a permselective membrane. The biosensor was incorporated into a commercially available, thin-layer, amperometric flow cell operated at a potential of only +0.05 V vs. Ag/AgCl. The mobile phase consisted of 0.2 M phosphate buffer pH 10 containing 0.1 M potassium chloride solution; a flow rate of 0.8 ml min(-1) was used throughout the investigation. The biosensor response was linear over the range 0.55-10 mM lactate; the former represents the detection limit. The precision of the system was determined by carrying out 10 repeat injections of 10 mM l(+)lactic acid standard; the calculated coefficient of variation was 4.28%. It was demonstrated that this biosensor system could be applied to the direct measurement of lactate in serum without pre-treatment; therefore, this would allow high throughput-analysis, at low cost, for this clinically important analyte.

A flow injection system, comprising a biosensor based on a screen-printed carbon electrode containing Meldola's Blue-Reinecke salt coated with glucose dehydrogenase, for the measurement of glucose.

A biosensor for the measurement of glucose in serum has been developed, based on a screen-printed carbon electrode modified with Meldola's Blue-Reinecke salt, coated with the enzyme glucose dehydrogenase (from Bacillus sp.), and nicotinamide adenine dinucleotide coenzyme (NAD+). A cellulose acetate layer was deposited on top of the device to act as a permselective membrane. The biosensor was incorporated into a commercially available, thin-layer, amperometric flow cell operated at a potential of only +0.05 V versus Ag/AgCl. The mobile phase consisted of 0.2 M phosphate buffer (pH 7.0) containing 0.1 M potassium chloride solution, and a flow rate of 0.8 ml min(-1) was used throughout the investigation. The biosensor response was linear over the range of 0.075-30 mM glucose, with the former representing the detection limit. The precision of the system was determined by carrying out 20 repeat injections of a 5-mM glucose standard, and the calculated coefficient of variation was 3.9%. It was demonstrated that this biosensor system could be applied to the direct measurement of glucose in serum without pretreatment. Therefore, this would allow high-throughput analysis, at low cost, for this clinically important analyte.

Application of screen-printed microband biosensors to end-point measurements of glucose and cell numbers in HepG2 cell culture.

Microband glucose biosensors were produced by insulating and sectioning through a screen-printed, water-based carbon electrode containing cobalt phthalocyanine redox mediator and glucose oxidase enzyme. Under quiescent conditions at 37 degrees C, at an operating potential of +0.4V, they produced an amperometric response to glucose in buffer solutions with a sensitivity of 26.4 nA/mM and a linear range of 0.45 to 9.0 mM. An optimal pH value of 8.5 was obtained under these conditions, and a value for activation energy of 40.55 kJ mol(-1) was calculated. In culture medium (pH 7.3), a sensitivity of 13 nA/mM was obtained and the response was linear up to 5 mM with a detection limit of 0.5 mM. The working concentration was up to 20 mM glucose with a precision of 11.3% for replicate biosensors (n=4). The microband biosensors were applied to determine end-point glucose concentrations in culture medium by monitoring steady-state current responses 400 s after transfer of the biosensors into different sample solutions. In conjunction with cultures of HepG2 (human Caucasian hepatocyte carcinoma) cells, current responses obtained in 24-h supernatants showed an inverse correlation (R(2)=0.98) with cell number, indicating that the biosensors were applicable for monitoring glucose metabolism by cells and of quantifying cell number. Glucose concentrations determined using the biosensor assay were in good agreement, for concentrations up to 20mM, with those determined spectrophotometrically (R(2)=0.99). This method of end-point glucose determination was used to provide an estimated rate of glucose uptake for HepG2 cells of 7.9 nmol/(10(6) cells min) based on a 24-h period in culture.

17beta-estradiol synthesis in the adult male rat retina.

17beta-Estradiol (E2) exerts neurotrophic and neuroprotective effects in the retina as well as in other CNS structures, independently of sex. Retinal effects, however, have not been supported by evidence on local synthesis, and whether CNS 17beta-estradiol is formed in a neurosteroidogenic pathway starting from cholesterol conversion into pregnenolone is a question still left unanswered. In the adult male rat retina, we have previously showed localization and activity of the P450 side chain cleavage (P450scc) enzyme, which is involved in pregnenolone synthesis. Here, we demonstrate both the mRNA and protein expression of 3beta-hydroxysteroid dehydrogenase (3beta-HSD), P450aromatase and also of P450scc, but only the protein expression of P450 17alpha-hydroxylase/lyase (P450c17). Using radiolabeled pregnenolone and testosterone as precursors, in the isolated and intact retina of adult male rats, E2 is produced in a large amount by each precursor within 1-4h, suggesting a highly active metabolic pathway towards its formation. The immunolocalization pattern shows enzymes and estrogen receptor subtypes (ERalpha, ERbeta) scattered in the retina with different intensities throughout the layers. The results point to the adult male rat retina as a neurosteroidogenic structure where E2 synthesis via a progesterone pathway and the presence of estrogen receptors provide important clues for understanding the neurotrophic and neuroprotective effects of the steroid hormone.

Transthoracic electrical bioimpedance: a non-invasive technique for the evaluation of the haemodynamic alterations in patients with liver cirrhosis.

BACKGROUND/AIM: Transthoracic electrical bioimpedance is a non-invasive technique for the evaluation of systemic haemodynamics. Compared to Doppler ultrasound, it has the advantage of being operator-independent, providing continuous monitoring and being less influenced by postural changes. Until now, transthoracic electrical bioimpedance has been applied to a very limited extent in liver cirrhosis. We, therefore, aimed to compare transthoracic electrical bioimpedance and echocardiography in the assessment of haemodynamic status in cirrhotic patients. PATIENTS/METHODS: Thirteen patients with compensated cirrhosis, 10 patients with cirrhosis and ascites and 12 controls were enrolled. Haemodynamic parameters (stroke volume, cardiac output, heart rate, mean arterial pressure and vascular peripheral resistance) were assessed simultaneously by transthoracic electrical bioimpedance monitoring with BioZ.com for at least 10 min and Doppler ultrasound. RESULTS: The absolute mean values of haemodynamic parameters obtained by the two techniques were quite similar in all groups; furthermore, a good agreement between transthoracic electrical bioimpedance and echocardiography measurements was found for all the parameters. Finally, transthoracic electrical bioimpedance proved easy to employ and provided continuous real-time monitoring of cardio-circulatory variations. CONCLUSIONS: The present study showed a significant correlation between transthoracic electrical bioimpedance and echocardiography in the assessment of systemic haemodynamics in patients with cirrhosis, supporting the employment of transthoracic electrical bioimpedance in pathophysiological studies requiring real-time continuous monitoring of haemodynamic parameters.