OBJECTIVE: To determine the usefulness of brain-derived neurotrophic factor (BDNF) as a diagnostic biomarker for colorectal cancer (CRC).MATERIALS AND METHODS: ELISA immunoassay was used to examine BDNF concentrations in the sera of two different retrospective cohorts consisting of CRC patients and age/gender matched controls. Cohort 1 consisted of 99 controls and 97 CRC patients, whereas cohort 2 consisted of 47 controls and 91 CRC patients.RESULTS: In cohort 1, the median concentration of BDNF was significantly (p < 0.0001) lower in CRC patient samples (18.8 ng/mL, range 4.0-56.5 ng/mL) than control samples (23.4 ng/mL, range 3.0-43.1 ng/mL). This finding was validated in an independent patient cohort (CRC patients: 23.0 ng/mL, range 6.0-45.9 ng/mL; control patients: 32.3 ng/mL, range 14.2-62.4 ng/mL). BDNF concentrations did not differ significantly between Dukes' staging in the patient cohort, however patients with Stages A, B, C and D (p < 0.01 for each stage) tumours had significantly reduced BDNF levels compared to healthy controls. Receiver operating characteristic analysis was performed to determine the ability of BDNF to discriminate between healthy controls and those with CRC. At 95% specificity, BDNF concentrations distinguished CRC patients with 25% and 18% sensitivity, respectively, in cohorts 1 and 2 (cohort 1: AUC = 0.79, 95% CI 0.70-0.87; cohort 2: AUC = 0.69, 95% CI 0.61-0.76).CONCLUSION: The serum levels of BDNF were significantly lower in colorectal cancer patients when compared to a control population, and this did not differ between different Dukes' stages.
High surface area cochlear implant electrodes with much smaller geometric surface areas than current designs might be used in the future to increase the number of stimulating electrodes along the carrier. Potential problems with an increase in charge density for a common stimulus resulting from decreasing the geometric surface area would be reduced by the enlarged real surface area of such electrodes. Electrochemically modified (HiQ) platinum (Pt) electrodes, with a real surface area ∼75 times greater than the current standard Pt electrodes of the same geometric size, had shown in vitro a low polarization (Zpol) and electrode impedance (Ze), as well as a low residual direct current (DC). In this study we examined the chronic performance of HiQ electrodes in cats, which were bilaterally implanted with a two-channel HiQ or standard Pt scala tympani electrode array and unilaterally stimulated for periods of up to 2390 h. Stimuli consisted of 50 μs/phase charge-balanced biphasic current pulses presented at 2000 pulses/s/channel with a 50% duty cycle. Electrode impedance (Ze), access resistance (Ra) and polarization impedance (Zpol) were calculated from current and voltage measurements obtained periodically throughout the implantation period. Immediately following implantation HiQ electrodes showed a significantly smaller Zpol, resulting in a reduced Ze (P<0.0001) compared to standard electrodes, while there was no significant difference between Ra of both electrode designs (P=0.91). Subsequently, Ze generally increased mainly due to a rise in Ra, which dominated Ze and obliterated the effect of a lower Zpol on Ze in HiQ electrodes. Peak Ra levels correlated closely (r=0.85) with the amount of intracochlear fibrous tissue found adjacent to the array. Following explantation of the array, voltage waveforms for both electrode designs recorded in saline were again very similar to those recorded immediately after implantation. Mean DC levels were consistently lower for HiQ electrodes compared with standard electrodes (22.45 nA vs 134.7 nA). Histopathological examination of corresponding cochlear sections comparing the stimulated test side with the unstimulated control side showed no significant difference (P>0.05) for either animals implanted with HiQ electrodes (n=6) or standard electrodes (n=2). Nor were there any significant differences between the spiral ganglion cell density of the basal turn implanted with HiQ or standard electrodes for both the stimulated test (P=0.31) and the unstimulated control side (P=0.84). Although these findings are based on a small group of animals implanted with standard electrodes (n=2), and those negative statistical results could potentially be due to the small sample size, similar spiral ganglion cell survival was found in a previous study of a larger group of animals using standard electrodes stimulated with the same stimulus paradigm as in the present study [Xu et al. (1997) Hear. Res. 105, 1–29]. Our data indicate that while some initial advantages of HiQ electrodes are lost during chronic implantation due to intracochlear fibrous tissue growth, low DC levels and the high surface area appear to be maintained, suggesting that HiQ electrodes may have important clinical applications.
OBJECTIVES:This study was designed to evaluate the efficacy and safety of the oxytocin receptor antagonist atosiban in the treatment of preterm labor. STUDY DESIGN:A multicenter, double-blind, placebo-controlled trial with tocolytic rescue was designed. Five hundred thirty-one patients were randomized to receive, and 501 received, either intravenous atosiban (n = 246) or placebo (n = 255), followed by subcutaneous maintenance with the assigned agent. Standard tocolytics as rescue tocolysis were permitted after 1 hour of either placebo or atosiban if preterm labor continued. The primary end point was the time from the start of study drug to delivery or therapeutic failure. Secondary end points were the proportion of patients who remained undelivered and did not receive an alternate tocolytic at 24 hours, 48 hours, and 7 days. RESULTS:No significant difference was found in the time from start of treatment to delivery or therapeutic failure between atosiban and placebo (median, 25.6 days vs 21.0 days, respectively; P =.6). The percentages of patients remaining undelivered and not requiring an alternate tocolytic at 24 hours, 48 hours, and 7 days were significantly higher in the atosiban group than in the control group (all P < or =.008). A significant treatment-by-gestational age interaction existed for the 48-hour and 7-day end points. Atosiban was consistently superior to placebo at a gestational age of > or =28 weeks. Fourteen atosiban-treated patients and 5 placebo-treated patients were randomized at <24 weeks; the incidence of fetal-infant deaths was higher for the atosiban group at <24 weeks. Maternal-fetal adverse events were similar except for injection-site reactions, which occurred more often with atosiban. CONCLUSIONS:In this trial the treatment of patients in preterm labor with atosiban resulted in prolongation of pregnancy for up to 7 days for those at a gestational age > or =28 weeks, and this occurred with a low rate of maternal-fetal adverse effects. In addition, at a gestational age > or =28 weeks, the infant morbidity and mortality of atosiban-initiated standard care were similar to those with placebo-initiated standard care. Given that all patients in this study were eligible for tocolysis and that, in practice, nearly all patients who are eligible for a tocolytic receive one, the benefit of using atosiban is the placebo-like maternal-fetal side effect profile. These observations support the use of this oxytocin receptor antagonist in the treatment of patients in preterm labor with intact membranes. Efficacy and infant outcome data at <28 weeks are inconclusive.
The electrochemistry of platinum electrodes in artificial perilymph solution subjected to cyclic and steady-state potentials was studied by a quartz crystal electrochemical microbalance and by analysis of electrolyte for dissolved platinum. The effect of amino acid adsorption appears to be one of blocking sites for platinum oxidation and oxide reduction, a process in which the amino acid competes with chloride from phosphate-buffered saline. For amino acids such as cysteine, which are known to interact strongly with platinum, the voltammograms became nearly featureless and only a small change in mass was observed during cycling of the potential. There were no mass changes of an electrode in solution containing human serum albumen, but its presence did inhibit dissolution of platinum. The overall magnitudes of dissolved platinum found in the buffered solutions were low, remaining below 5 ppb in most cases. Dissolution was greatest in solutions containing high concentrations of cysteine. Extrapolation of the results to implanted auditory prosthesis electrodes indicated that platinum dissolution would not lead to toxic concentrations in the body.
Neural prostheses use charge recovery mechanisms to ensure the electrical stimulus is charge balanced. Nucleus cochlear implants short all stimulating electrodes between pulses in order to achieve charge balance, resulting in a small residual direct current (DC). In the present study the authors sought to characterize the variation of this residual DC with different charge recovery mechanisms, stimulation modes, and stimulation parameters, and by modeling, to gain insight into the underlying mechanisms. In an acute study with anaesthetised guinea pigs, DC was measured in four platinum intracochlear electrodes stimulated using a Nucleus(R) CI24M cochlear implant at moderate to high pulse rates (1200-14 500 pulses/s) and stimulus intensities (0.2-1.75 mA at 26-200 /spl mu/s/phase). Both monopolar and bipolar stimulation modes were used, and the effects of shorting or combining a capacitor with shorting for charge recovery were investigated. Residual DC increased as a function of stimulus rate, stimulus intensity, and pulse width. DC was lower for monopolar than bipolar stimulation, and lower still with capacitively coupled monopolar stimulation. The authors' model suggests that residual DC is a consequence of Faradaic reactions which allow charge to leak through the electrode tissue interface. Such reactions and charge leakage are still present when capacitors are used to achieve charge recovery, but anodic and cathodic reactions are balanced in such a way that the net charge leakage is zero.
Dialysis neutropenia is the result of pulmonary sequestration of neutrophils after complement activation by the dialyzer membrane. Increased expression of neutrophil adhesion receptors, such as CD11b/CD18, suggests that neutrophil adhesion to the capillary endothelium is a possible mechanism. An alternative hypothesis is that the complement fragment C5a modulates neutrophil mechanical properties via the cytoskeleton-largely filamentous actin (F-actin)-stiffening them and thereby slowing their passage through the pulmonary capillaries. To investigate this hypothesis, we developed an assay to measure the F-actin content of neutrophils in whole blood using flow cytometry and the stain NBD-phallacidin. We measured neutrophil F-actin content during hemodialysis of patients with polysulfone (N = 6), Hemophan (N = 6), and Cuprophan membranes sterilized with either ethylene oxide (N = 5) or steam (N = 6). Cell counts, neutrophil and monocyte CD11b expression and plasma C5a concentrations were also measured. The results confirm the strong relationship between the degree of neutropenia, increases in CD11b expression and plasma C5a levels reported by previous researchers. Modulation of the F-actin content of neutrophils was also strongly related to C5a levels, indicating that the neutrophil cytoskeleton is active during dialysis. Modeling of cell counts suggests that with Cuprophan a substantial fraction of neutrophils and monocytes are sequestered before they even pass through the dialyzer, suggesting some form of systemic activation of these cells. Evidence for systemic activation was also seen in measurements of F-actin content, but not CD11b expression, a finding that strengthens the case for the involvement of the cytoskeleton in dialysis neutropenia.
Direct current (DC) was measured both in vivo and in vitro in cochlear implant electrodes with stimulation at moderate to high pulse rates in monopolar and bipolar modes. In vivo DC was approximately 2-3 times higher than that measured in vitro. In vivo DC levels were <100 nA even at very high rates, although DC levels increased as a function of stimulus rate and charge intensity. DC levels were lower in the monopolar than in the bipolar stimulation condition. Stimulation with a monopolar capacitively coupled extracochlear electrode showed even lower DC levels in the intracochlear electrodes. The authors' results indicated that the Nucleus electrode shorting system is able to maintain a low level of DC during very high rate stimulation for both monopolar and bipolar modes.
OBJECTIVE: Our purpose was to determine the efficacy of a home uterine activity monitoring system for early detection of preterm labor and reduction of preterm birth. STUDY DESIGN: A randomized, controlled, double-blinded trial was performed in which pregnant women between 24 and 36 weeks' gestation and at high risk for preterm labor or birth were assigned to receive twice daily nursing contact and home uterine activity monitoring with either active (data revealed) or sham (data concealed) devices. Study end points included mean cervical dilatation and its mean change from a previous visit at preterm labor diagnosis, preterm birth rate, and infant outcomes. Analysis of variance or logistic models including terms for site and group-by-site interaction effects were constructed for all variables. RESULTS: Of 1355 patients enrolled, 1292 were randomized, 1165 used home uterine activity monitoring devices, and 842 (72.3%) completed the study. Both device groups had similar demographics, enrollment and delivery gestational ages, discontinuation rates, risk factors, birth weights, cervical dilatation at enrollment and at preterm labor diagnosis, change in cervical dilatation at preterm labor diagnosis, rates of preterm labor and birth, and neonatal intensive care requirements. Power to detect a difference in cervical dilatation greater than or equal to 1 cm at diagnosis of preterm labor was 0.99 for all risk factors. CONCLUSIONS: Uterine activity data obtained from home uterine activity monitoring, when added to daily nursing contact, were not linked to earlier diagnosis of preterm labor or lower rates of preterm birth or neonatal morbidity in pregnancies at high risk for preterm labor and birth.
Transient leukopenia and complement activation are well documented in hemodialysis (HD). To elucidate the mechanisms involved in these processes the expression of adhesion receptor molecules was investigated on neutrophils (PMN) and monocytes in 26 patients dialysed with different dialyzer membrane materials. Blood was obtained from dialyzer inlets and outlets for determination of C3a/C5a desArg by ELISA and expression of integrins CD11b (CR3), CD11c (CR4) and complement receptor CD35 (CR1) by flow cytometry. Expression of all three receptors was found significantly upregulated in PMN and monocytes occurring rapidly after start of HD and correlating with maximal neutropenia and complement activation. Our results demonstrate that leukopenia and complement activation are associated with an upregulation of cell surface receptor molecules. These adhesion proteins could be involved in leukocyte aggregation, and adherence to endothelia or foreign surfaces.
Adult sheep (35 +/- 3 kg) underwent saline lung lavage and 1.5 h of mechanical ventilation to induce acute lung injury. Animals received 100 mg lipid/kg body wt of tracheally instilled surfactant (Inst Surf) or either nebulized surfactant (Neb Surf) or nebulized saline (Neb Saline) and were killed 3 h later. Inst Surf and Neb Surf groups had significant improvements in oxygenation (P < 0.01) and peak inspiratory pressures (PIP) (P < 0.05) compared with pretreatment values. Improvements in oxygenation and PIP for Inst Surf animals were significantly greater than for Neb Surf animals (P < 0.05). Volumes of maximal pressure of quasi-static pressure-volume curves measured at the time the animals were killed were significantly greater for Inst Surf and Neb Surf animals than for animals given Neb Saline (P < 0.05). Alveolar recovery of exogenous surfactant was 100 times greater for Inst Surf animals (1,732 +/- 70 mg) than for Neb Surf animals (15.3 +/- 2.9 mg) at the time they were killed. Although there were no differences in exogenous surfactant distribution patterns at the lobar level between the two surfactant-treated groups, distribution histograms calculated for 10-g lung pieces revealed the Neb Surf animals had significantly more pieces within 25% of the mean value of 1.0 (42.7 +/- 6.9%) than did Inst Surf animals (20.8 +/- 5.5%) (P < 0.01). Exogenous surfactant therapy improved lung function with significantly different quantities of surfactant deposited in lung tissue for the two delivery methods evaluated.
Objective To review the clinical and urodynamic outcome of treatment by the modified Pereyra procedure in 93 women with genuine stress incontinence.Design Retrospective review.Setting Harbor/UCLA Medical Center and Los Angeles County Women's Hospital, Los Angeles, California, USA.Main outcome measures Clinical and urodynamic assessment one year after modified Pereyra procedure.Results Overall 82% of patients were subjectively cured while only 63% were objectively cured. Women with failed surgery had significantly lower pre-operative maximum urethral closure pressures. The procedure had a low operative and post-operative morbidity with no significant disturbance of voiding function noted at one year follow-up.Conclusions Our results with the modified Pereyra procedure for stress incontinence showed a significantly lower success rate than has been reported from many previous studies.
The 1-hour net accumulation of four labeled proteins of different sizes (6.5, 29, 69 and 150 kD) from the vascular space into the lungs and airspaces was measured in preterm ventilated lambs at 132 days gestational age. Lambs treated with Survanta® a surfactant prepared from bovine lung, were studied at 1 3, 5 and 8 h after birth, while lambs not treated with this surfactant were studied up to 5 h of age because of severe respiratory failure. The labeled proteins were lost from the vascular space more rapidly over the first 1 h of life than at later times (p < 0.01). Labeled protein recoveries were similar at 1 and 3 h in surfactant and control lambs and decreased by 8 h in surfactant-treated lambs (p < 0.05). In both the surfactant-treated and control animals, there was a sequential decrease in labeled protein recoveries based on protein size (p < 0.01). There was no change with time in size selectivity for accumulation of the labeled proteins into the lungs for either the control or surfactant-treated lambs, although surfactant treatments decreased accumulation of the 6.5 and 29 kD proteins at 5 h when compared to the control group (p < 0.05). Labeled protein recoveries in alveolar washes demonstrated less size selectivity. These studies documented that size selectivity of the vascular endothelium did not change over the first 8 h of life in preterm ventilated lambs, a pattern that was not indicative of progressive lung injury.
Four groups of twin sheep fetuses were catheterized at 121 days of gestational age and intravenously infused with saline, 0.75 mg.kg-1.h-1 cortisol for 60 h, five intermittent bolus injections of 5 micrograms/kg thyrotropin-releasing hormone (TRH) at 12-h intervals, or both hormones before delivery at 128 days. At birth, the lambs were randomized to receive surfactant or no treatment. Surfactant treatment improved lung function of all the groups. Corticosteroids alone and in combination with TRH improved compliance and gas exchange as well as pressure-volume curves. Corticosteroids alone dramatically decreased the recovery of intravenously administered radiolabeled albumin in the lung tissue and air space and improved the pulmonary response to surfactant treatment. There were no additional effects of TRH when given with corticosteroids on lung function or albumin leak. There were no changes in alveolar surfactant-saturated phosphatidylcholine pool sizes after any hormone treatment. The single significant effect of combined corticosteroid and TRH treatment was a fivefold increase in surfactant protein A in alveolar lavage fluid relative to all other groups.
To evaluate the potential for aerosolized surfactant treatments of surfactant deficiency, twin lamb fetuses were delivered at 130-132 days gestational age and received nebulized natural surfactant (Neb NS), nebulized Survanta (Neb Surv), tracheally instilled natural surfactant (Inst NS), or nebulized saline (Neb Saline). Neb NS and Neb Surv groups had significant increases in ventilatory efficiency index and dynamic compliance values (P less than 0.05). Both groups also had pressure-volume curves that were comparable to the Inst NS group. The Neb Saline control group had deterioration of the ventilation efficiency index and dynamic compliance values over time as well as pressure-volume curves that demonstrated smaller lung volumes compared with all three surfactant-treated groups (P less than 0.01). Delivery of aerosolized surfactant to the lung was only approximately 2 mg lipid/kg for the nebulized groups, a dose one-twentieth of that previously noted to be effective in instillation protocols. Distribution histograms of the aerosolized surfactant-treated groups differed from the instilled animals as there was more deposition in the right upper lobes and tracheae in the nebulized groups compared with the instilled group (P less than 0.05). Pulmonary blood flow was not altered by aerosolized surfactant treatment. Administration of aerosolized surfactant to preterm lambs improved lung function at a very low surfactant dose.
ABSTRACT: Palmitic acid is a minor component of natural surfactant and has been used to modify lipid extracts of natural surfactants to optimize their in vitro surface properties. The metabolic fate of palmitic acid in surfactant is unknown. The clearance of surfactant-associated radiolabeled palmitic acid after intratracheal administration was investigated with trace doses of surfactant in the adult rabbit and with trace and treatment doses in the 28-d fetal rabbit and the 132-d fetal sheep. Palmitic acid was cleared rapidly from the airways, with less than 2% of the radiolabel recovered as free palmitic acid in the alveolar wash by l h in all models. Recovery as free palmitic acid in the total lung at 2 h was 2% in the adult rabbit and 3% both doses in the preterm rabbit. In the preterm sheep, the recovery as free palmitic acid in the total lung was approximately 2% of the trace dose and 1 % of the treatment dose by 5 h. Between 5 and 15% of the instilled palmitic acid was used as substrate for phospholipid synthesis by the lung in the different models. About 30% of the palmitate derived label was recovered in lipid extracts of liver 30 min after trachéal instillation of labeled surfactant in adult rabbits, whereas only 5—10% of the palmitate derived label was found in liver lipids in the preterm animals. In contrast to palmitic acid, radiolabeled triglycéride was cleared much more slowly from the airspaces and lungs of preterm sheep. Inasmuch as large amounts of palmitic acid are cleared rapidly from airspaces and lung tissue, it will not have a prolonged effect on the surface properties of surfactant but it may serve as a precursor for lung lipid metabolism.
Vulvar biopsy specimens from 16 patients with gross lesions of the vulva consistent with vulvar dystrophy were examined histologically and for the presence of human papillomavirus deoxyribonucleic acid by southern blot hybridization. None of the nonatypical dystrophies probed positive for human papillomavirus; however, three of five atypical hyperplastic dystrophies (vulvar intraepithelial neoplasia) contained human papillomavirus deoxyribonucleic acid type 16. We conclude that human papillomavirus does not seem to be a causal factor in nonatypical chronic epithelial changes of the vulva.