Comparison of A-mode ultrasound and computed tomography: detection of secretion in maxillary and frontal sinuses in ventilated patients.

OBJECTIVE: To study the accuracy of A-mode ultrasonography (A-MU) in detecting secretion in maxillary and frontal sinuses in critically ill, intubated patients undergoing mechanical ventilation. DESIGN: Open study in mechanically ventilated, comatose patients. SETTING: Medical-surgical intensive care unit in the General Hospital of Rovigo. PATIENTS: 50 consecutive, mechanically ventilated, critically ill patients. All patients were in a coma and needed cerebral computed tomography (CT) for a diagnosis. MEASUREMENTS AND RESULTS: The A-MU technique gave 100 images of maxillary and frontal sinuses. The images were read blindly and classified into five categories: definitely normal, definitely abnormal, probably normal, questionable, and probably abnormal. CT findings were considered to be the "gold standard". The specificity of echo images varied from 72 to 98% and the sensitivity from 63 to 86% for maxillary sinuses. For frontal sinuses, the specificity varied from 96 to 99% and the sensitivity from 14 to 57%. The area under the receiver-operating characteristic curve was found to be 0.89 and 0.76 for maxillary and frontal sinuses, respectively. CONCLUSIONS: The A-MU technique is an accurate tool for detecting secretion in the maxillary sinuses in intubated patients. More investigations are necessary in order to evaluate its usefulness in the frontal sinuses.

Neuroprotective effect of reduced glutathione on cisplatin-based chemotherapy in advanced gastric cancer: a randomized double-blind placebo-controlled trial.

PURPOSE: We performed a randomized double-blind placebo-controlled trial to assess the efficacy of glutathione (GSH) in the prevention of cisplatin (CDDP)-induced neurotoxicity. PATIENTS AND METHODS: Fifty patients with advanced gastric cancer treated with a weekly CDDP-based regimen were included in this study. In patients randomized to receive GSH, GSH was given at a dose of 1.5 g/m2 in 100 mL of normal saline solution over a 15-minute period immediately before CDDP administration, and at a dose of 600 mg by intramuscular injection on days 2 to 5. Normal saline solution was administered to placebo-randomized patients. Clinical neurologic evaluation and electrophysiologic investigations have been performed at baseline and after 9 (CDDP dose, 360 mg/m2) and 15 (CDDP dose, 600 mg/m2) weeks of treatment. RESULTS: At the 9th week, no patients showed clinically evident neuropathy in the GSH arm, whereas 16 patients in the placebo arm did. After the 15th week, four of 24 assessable patients in the GSH arm suffered from neurotoxicity versus 16 of 18 in the placebo arm (P = .0001). In confirmation of this neuroprotective effect, the neurophisiologic investigations, based on the evaluation of the median, ulnar, and sural sensory nerve conduction, showed a statistically significant reduction of these values in the placebo arm but not in the GSH arm, above all considering potential amplitude. In this trial, GSH also reduced hemotransfusion requirements (32 v 62 hemotransfusions) and treatment delay (55 v 94 weeks). The response rate was 76% (20% complete response) in the GSH group and 52% (12% complete response) in the placebo arm, confirming preliminary reports about the lack of reduction in activity of cytotoxic drugs induced by GSH. CONCLUSION: This study provides evidence that GSH is a promising and effective new drug for the prevention of CDDP-induced neuropathy, and that it does not reduce the clinical activity of chemotherapeutic drugs.

A method for improving classification reliability of multilayer perceptrons.

Criteria for evaluating the classification reliability of a neural classifier and for accordingly making a reject option are proposed. Such an option, implemented by means of two rules which can be applied independently of topology, size, and training algorithms of the neural classifier, allows one to improve the classification reliability. It is assumed that a performance function P is defined which, taking into account the requirements of the particular application, evaluates the quality of the classification in terms of recognition, misclassification, and reject rates. Under this assumption the optimal reject threshold value, determining the best trade-off between reject rate and misclassification rate, is the one for which the function P reaches its absolute maximum. No constraints are imposed on the form of P, but the ones necessary in order that P actually measures the quality of the classification process. The reject threshold is evaluated on the basis of some statistical distributions characterizing the behavior of the classifier when operating without reject option; these distributions are computed once the training phase of the net has been completed. The method has been tested with a neural classifier devised for handprinted and multifont printed characters, by using a database of about 300000 samples. Experimental results are discussed.

[Interferon-alpha. Results of a pharmaco-epidemiologic study]. / Interferone alfa. Risultati di uno studio farmaco-epidemiologico.

In the present study we evaluated the use of alpha-IFN in the ULSS 21 of Veneto Region. All outpatients treated with interferon during the period June-July 1992 (114 subjects) were interviewed using a standard questionnaire which was meant to collect information about therapy, side effects and quality of life. Alpha-IFN was mostly prescribed for chronic non-A non-B hepatitis (as approved by the FDA in the USA and by the Ministero della Sanità in Italy), while 35% of the patients were suffering from diseases for which interferon use is approved by Ministero della Sanità but not by FDA. In most cases, independently of the specific disease, a standard dose of 9 MU/week was used, which often resulted to be below the recommended doses reported in the literature. Adverse effects were frequently reported. The most common include fever, chills, headache, fatigue, myalgia. Mild mental disturbances (irritability and/or depression) and thyroid dysfunction were also reported but were less frequent. Finally, a negative influence of alpha-IFN therapy on the quality of life was reported by about half of the interviewed patients.

Regressing intracranial carotid occlusions in childhood.

Though detected with increasing frequency, intracranial carotid artery dissection remains less common in infancy. We report on 3 otherwise healthy children aged 8, 12 and 15 years who presented with focal headache and stroke secondary to intracranial carotid occlusive disease consistent with arterial dissection. In 2 cases this was precipitated by strenuous physical exertion. The protean angiographic configuration included long tapered narrowing with focal stenosis, beaded narrowing with Moya Moya vascular network and 'string sign'; occlusion of the anterior cerebral artery was always present. Control angiograms revealed complete or partial recanalization in all cases suggesting self-healing dissection. The clinical course was smooth in all patients, and at long-term follow-up (5, 3, and 2 years) they remain in good neurological condition. Although intracranial carotid dissection has a poor reputation, regression to normal and fair outcome may sometimes occur as in the extracranial counterpart, suggesting the existence of benign forms of the disease. Surgical procedures should be weighed against the spontaneous resolution of the lesion.

From local maxima to connected skeletons.

In picture processing it is often convenient to deal with a stick-like version (skeleton) of binary digital images. Although skeleton connectedness is not necessary for storage and retrieval purposes, this property is desirable when a structural description of images is of interest. In this paper a parallel procedure is described which, applied to a connected image, originates a connected skeleton made by the union of simple digital arcs. The procedure involves a step by step propagation of the background over the image. At every step, contour elements either belonging to the significant convex regions of the current image or being local maxima of the original image are selected as skeleton elements. Since the final set so obtained is not ensured to be connected, the configurations in correspondence of which disconnections appear are investigated and the procedures to avoid this shortcoming are given. The presence of the whole set of local maxima among the skeleton elements ensures the possibility of recovering the original image by means of a reverse distance transform. The details of the program implementing the proposed algorithm on a parallel processor are finally included.

Modulation of Hydra attenuata rhythmic activity: phase response curve.

We investigated the effect of photic stimulation on the frequency of Hydra attenuata column contractions. We used positive or negative abrupt light transitions, single or repetitive light or darkness pulses, and alternation of light and darkness periods. The main results are: (a) The frequency of the contraction pulse trains (CPTs) varies transiently in response to an abrupt variation of the light intensity. (b) CPTs in progress can be inhibited by different types of photic stimuli. (c) The response time to a single photic stimulus varies during the inter-CPT interval and depends also on the polarity of the stimulus. (d) The CPTs are entrainable with repetitive light stimulation of various frequencies. (e) Long-lasting variations of the frequency of CPTs occur after the end of a repetitive light stimulation. We suggest that the mechanism responsible for the rhythym of column contractions is quite similar to that on which other biological rhythmic phenomena are based.

Modulation of Hydra attenuata rhythmic activity. Photic stimulation.

We investigated in Hydra attenuata the possibility of altering more or less permanently and in different environmental conditions, the frequency of Contraction Pulse Trains (CPT's) associated with the rhythmic spontaneous contraction activity, by repetitive light stimuli of variable duration, frequency and amplitude. The CPT's activity of various pieces of Hydra has been also investigated in indisturbed conditions and under stimulation. The following observations have been performed. 1. A transient effect, consisting of an increase or a decrease of CPT's frequency, occurs respectively after an abrupt decrease or increase of the light level. 2. If Hydra is stimulated by repetitive light pulses of 0.5-10 sec duration, at a frequency different from the CPT's average one, the CPT's frequency modifies; if the stimulation frequency is included in a range not too much up or below that of CPT's the new CPT's frequency equals exactly that of stimulation; close to this range the CPT's frequency is a multiple or submultiple of that of stimulation. 3. No habituation to such repetitive stimulation was found. 4. The phase relation between CPT's at the new frequency and light stimuli is a function of the difference between CPT's and stimulation frequencies. 5. Stimulation with repetition of light and darkness periods of some minutes duration induces activity only or mainly during darkness. 6. Modification of CPT's frequency by means of repetitive light stimulation [of the type mentioned either in 2) or 5)] has been observed also with hypostomal preparations. 7. With cessation of the light stimulation, the new CPT's frequency of the whole animal lasts in darkness for a time (10-85 min) that is about 5-10 times longer than that necessary to obtain CPT's syncronization with stimulation. 8. The influence of the light intensity level on transient CPT's frequency variation (see 1), CPT's inhibition and stimulation, promptness of entrainment, range of entrainability, phase relation between entrained CPT's and stimuli, retention time of entrained rhythm has been examined, together with the influence of the reversal of polarity of light transitions on CPT's inhibition and entrainment.