Prediction of efficacy of octreotide therapy in patients with acromegaly

Octreotide (OCT) administration provides a biochemical cure in most acromegalic patients. This drug, however, causes several side effects and is very expensive. Acute testing has been reported to predict chronic responsiveness to OCT administration. The aim of this retrospective study was to evaluate which test, if any, among acute testing, short-term (1 month) administration, and 111In-pentetreotide (111In-DTPA-Phe-D-OCT) scintigraphy, is best in predicting response to long-term OCT treatment. Sixty-eight patients with active acromegaly were studied. An acute test (100 micrograms sc OCT) was performed as usual: a GH decrease greater than or equal to 50% of baseline was considered a positive response. GH and insulin-like growth factor I (IGF-I) were then assayed after 1 month (300 micrograms daily) and 3 months (150-600 micrograms daily) of OCT administration. GH was considered normalized when decreased less than or equal to 5 micrograms/L. Twenty-six of 68 patients were subjected to 111In-pentetreotide scintigraphy. Linear correlation analysis of the results was performed. Sensitivity, specificity, and positive and negative predictive values of the three tests were also calculated. Thirty-eight of 68 patients (56%) responded to the acute test. Among these 38 patients, 20 experienced normalization of GH and IGF-I levels during long-term therapy, as did 8 patients who did not respond to the acute test. No significant correlation was found between GH percent decrease during acute testing and long-term therapy (r = 0.11). Seven patients who responded to the acute test and 2 who did not respond had adenoma shrinkage during therapy. Conversely, GH and IGF-I decrease after short-term treatment significantly correlated with long-term treatment (r = 0.76 and 0.64, P < 0.01). Of the 26 patients subjected to 111In-pentetreotide scintigraphy, 13 had significant tracer uptake: normalization of GH and IGF-I was obtained in 8 patients. A significant correlation was found between tracer uptake and GH/IGF-I inhibition after 3 months of therapy (r = 0.6; P < 0.05). In the whole population, the positive predictive value of acute testing, short-term OCT administration, and 111In-penetreotide scintigraphy was 53%, 70%, and 73%, respectively, when the GH normalization (< 5 micrograms/L) after 3 months of therapy was considered. Moreover, 111-In-pentetreotide scintigraphy had the highest specificity (100% in patients with baseline GH values below 50 micrograms/L) compared with that of acute testing and short-term OCT administration. The acute test cannot be considered as a valuable index to identify patients' responsiveness to long-term OCT therapy, but it can be useful to test tolerability. By contrast, 1 month of OCT administration or the in vivo imaging of somatostatin receptors by 111-In-pentetreotide might better indicate the patients who might effectively benefit from this treatment.     

A correlator for light scattering experiments

Light scattering is frequently used to examine the random motion of physical system particles. By evaluating the autocorrelation function of the acquired signal, structural information of macromolecular solutions can be obtained. Here we present an instrument that is able of calculating the correlation function in real time. The instrument features high-precision capabilities and a wide range of selectable delays. A digital signal processor (DSP) is charged with the calculations, whereas a PC permits the user the management of the global instrument and the visualization and the storing of the evaluated correlation     

Analysis and measurement of timing jitter induced by radiated EMI noise in automatic test equipment

This paper deals with the generation, measurement and modeling of the jitter encountered in the signals of a testhead board for automatic test equipment (ATE). A novel model is proposed for the jitter; this model takes into account the radiated electromagnetic interference (EMI) noise in the head of an ATE. The RMS value of the jitter is measured at the output signal of the testhead board to validate the proposed model. For measuring the RMS value, a novel circuitry has been designed on a daughter board to circumvent ground noise and connectivity problems arising from the head environment. An H-field is applied externally at the loop filter of a phase-locked loop (PLL), thus permitting the measurement of the RMS jitter to verify the transfer function between radiated EMI and jitter variation. The error between measured and predicted jitters is within a 15% level at both 200 kHz and 500 kHz.     

Acute renal failure in open heart surgery

A case-control study was performed to establish possible risk factors for acute renal failure (ARF) and mortality in patients undergoing cardiac surgery. A consecutive series of 704 patients were included in the study. A randomized sample of 255 patients was taken to analyze risk factors for ARF and mortality. Incidence of acute renal failure was 3.8% (27/704). Low cardiac output (LCO) was observed in all patients who developed ARF and in 72/255 without ARF (p < 0.0005). When LCO was isolated, no difference was found between groups. Association to prolonged perfusion time and sepsis increased the probability of developing ARF: 5/27 versus 0/255, p < 0.001; and 9/27 versus 0/255, p < 0.001, respectively. Overall mortality was 7.2% (51/704). Significant difference was found between ARF (55.6%, 15/27) and non-ARF patients (5.4%, 36/704), p < 0.005. Neither age nor sex was associated to outcome. Nonsurvivor patients were more oliguric (11/15 vs. 0/12, p < 0.005), required dialysis more frequently (7/15 vs. 0/12, p < 0.005), and were complicated with sepsis more often (9/15 vs. 0/12, p < 0.005), compared to survivors. We concluded that ARF was an uncommon complication in this group of patients, but mortality rate was dramatically high. This study identified LCO associated to prolonged perfusion time and sepsis as risk factors for ARF. Severity of ARF (oliguric forms and dialysis requirement) and postoperative events (sepsis) were associated with mortality.     

Esophago-jejuno-gastroplasty in the treatment of peptic stenosis of the esophagus]

Resistance to benzalkonium chloride (BC) among Pseudomonas spp. isolated from poultry carcasses was determined and strategies for elimination of resistant strains evaluated. This investigation showed that resistance was quite common, about 30% of the isolates being able to grow in 200 micrograms ml-1 BC. Pseudomonas fluorescens strains were generally less susceptible than strains of Ps. lundensis and Ps. fragi. An overnight incubation in medium containing 200 micrograms ml-1 BC was sufficient to reduce the susceptibility of two Pseudomonas strains to the lethal effect of BC significantly. Adding EDTA enhanced the lethal effect of BC, but the effect was reduced after growing cells in medium containing BC and EDTA. Growth in medium with a quaternary ammonium compound (QAC) rendered the cells more susceptible to chlorine, phenolics, and alkylaminoacetate. These results indicate that alternating use of QACs with these compounds can be used to avoid build-up of resistant strains. In addition, increased temperatures improved the lethal effect of BC and should be considered when planning disinfection routines.     

Carbon dioxide removal in power generation using membrane technology

Carbon dioxide separation by means of membranes from methane reformed synthesis gas and from semi-closed cycle flue gases has been studied. In the first case, removing carbon dioxide using membrane is more energy consuming than removing it, from the same synthesis gas, using chemical absorption, leading to overall energy conversion efficiency of about 39% for the recuperated-auto thermal reforming (R-ATR) cycle equipped with membrane vs. 45% for the same R-ATR equipped with chemical absorption. With reference to the semi-closed cycle, the net cycle efficiency in the case of membrane removal (42.7%) seems to be not very far from the chemical absorption case (46%). Finally, published data about CO₂ membrane separation specific cost have been analysed, showing that the membrane technology for flue gas application can be competitive with respect to chemical absorption if CO₂ flue gas concentration is higher than 10%.     

Hirunorms are true hirudin mimetics. The crystal structure of human alpha-thrombin-hirunorm V complex

OBJECTIVE: Pelvic pain can account for up to 40 percent of laparoscopies performed by gynecologists. This report compares the psychological profiles and efficacy of laparoscopic surgery at long-term follow-up in a series of laparoscopy-positive and laparoscopy-negative patients with chronic pelvic pain. METHOD: A retrospective chart review was performed on patients diagnosed with chronic pelvic pain combined with postoperative written questionnaires and self-rating scales. These questionnaires were used to assess long-term post laparoscopy follow-up of the physical and psychological status of women with positive findings at laparoscopy compared to those women with negative findings. RESULTS: There were no statistically significant demographic differences between respondents and nonrespondents. In the respondents, no statistically significant differences were noted even with long-term follow-up when comparing responses of the laparoscopy-positive and laparoscopy-negative groups on the above questionnaires. CONCLUSION: Though reporting modest improvement in pelvic pain since laparoscopy, both groups reported a high incidence of anxiety, depression, physical worries, and marital/sexual problems.     

FAD-mediated enzymatic conversion of NAD+ to NADH: application to chiral synthesis of L-lactate

Electroenzymatic reduction of NAD+ to NADH for subsequent use in enzymatic synthesis has been carried out at carbon electrodes bearing lipoamide dehydrogenase (LiDH) immobilized under a Nafion film. The self-mediated electron transfer was made possible by an excess of flavin adenine dinucleotide (FAD) entrapped together with LiDH. Results were compared to those obtained with a similar electrode containing both LiDH and a polymeric form of FAD (pFAD) prepared by anodic polymerization of FAD.     

Performance analysis of an adaptive receiver structure for digital mobile communications

In this paper we investigate the performance of a combined estimation/equalization technique for the mobile radio channel, assuming a GSM-recommended transmission format (narrowband TDMA with midamble, recommendation 5.04) and MSK modulation scheme. Channel estimation is performed via correlation of the received signal with a suitably modulated replica of the transmitted midamble. Equalization is then obtained by means of a maximum likelihood sequence estimation (MLSE) scheme in the form of a so-called Viterbi equalizer. Our analysis provides theoretical results concerning the bit error rate (BER) attained by the receiver for a given stationary multipath channel model. Simulation results are also presented in order to integrate and validate the theory.     

Long-term and low-dose treatment with cabergoline induces macroprolactinoma shrinkage

Cabergoline (CAB), a long-lasting dopamine-agonist, specific for the D2 receptor, is effective in normalizing serum PRL levels in most patients with microprolactinoma or idiopathic hyperprolactinemia. Because few data are presently available on the effects of CAB treatment in macroprolactinomas, the aim of this open-label study was to investigate whether this drug was effective in producing tumor shrinkage, as well as in normalizing PRL levels. Twenty-three patients with macroprolactinoma entered this study 15 patients had had no treatment, whereas the remaining 8 patients had been previously treated with bromocriptine, which was with-drawn because of intolerance. Three of 23 patients had undergone unsuccessful surgery. Pretreatment serum PRL levels ranged from 100-3860 micrograms/L. CAB was administered at a dose of 0.5-3 mg once or twice a week for 12-24 months. Magnetic resonance imaging (MRI) scans were performed before and 3, 6, 12, and 24 months after the beginning of treatment, to evaluate tumor shrinkage, defined as a decrease of at least 80% of baseline tumor volume. After 3-6 months of treatment with a low dose (0.5-1 mg/week), serum PRL levels normalized in 18 patients. In the remaining 5 patients, whose serum PRL levels were not normalized, the dose was increased to 2-3 mg/week. This schedule caused the normalization of PRL levels in 1 patient, whereas in the remaining 4 patients, PRL levels were reduced to 30-82 micrograms/L. A tumor volume reduction greater than 80% at MRI occurred in 14 of 23 patients (61%) after CAB treatment (from 2609.4 +/- 534.7 to 530.1 +/- 141.3 mm3 at the 12-24th month follow-up, P < 0.001). A volume reduction of 41.8 +/- 3.4% was already evident after 3 months (1436 +/- 285.9 mm3; P < 0.001). The complete disappearance of the tumor mass at MRI occurred after 6 months of treatment with CAB in 1 patient, and in 5 patients after 1 yr of treatment. An improvement of visual field defects was obtained in 9 of the 10 patients presenting visual impairment before CAB treatment. The drug was tolerated well by all patients. Only 1 patient experienced mild nausea, which disappeared spontaneously after the 2nd day of treatment. Long-term, a low dose of the D2 receptor agonist CAB significantly reduced tumor volume and normalized serum PRL levels in a great majority of patients bearing macroprolactinoma. This treatment met with excellent patient compliance. This study suggests that CAB can be used as a first choice drug treatment in macroprolactinomas, as already shown for microprolactinomas and idiopathic hyperprolactinemia.