Showing papers by "University of Milan published in 1986"

Intimal plus medial thickness of the arterial wall: a direct measurement with ultrasound imaging.

Abstract: A study in vitro of specimens of human aortic and common carotid arteries was carried out to determine the feasibility of direct measurement (i.e., not from residual lumen) of arterial wall thickness with B mode real-time imaging. Measurements in vivo by the same technique were also obtained from common carotid arteries of 10 young normal male subjects. Aortic samples were classified as class A (relatively normal) or class B (with one or more atherosclerotic plaques). In all class A and 85% of class B arterial samples a characteristic B mode image composed of two parallel echogenic lines separated by a hypoechoic space was found. The distance between the two lines (B mode image of intimal + medial thickness) was measured and correlated with the thickness of different combinations of tunicae evaluated by gross and microscopic examination. On the basis of these findings and the results of dissection experiments on the intima and adventitia we concluded that results of B mode imaging of intimal + medial thickness did not differ significantly from the intimal + medial thickness measured on pathologic examination. With respect to the accuracy of measurements obtained by B mode imaging as compared with pathologic findings, we found an error of less than 20% for measurements in 77% of normal and pathologic aortic walls. In addition, no significant difference was found between B mode-determined intimal + medial thickness in the common carotid arteries evaluated in vitro and that determined by this method in vivo in young subjects, indicating that B mode imaging represents a useful approach for the measurement of intimal + medial thickness of human arteries in vivo.

Dementia and Working Memory

Abstract: This study explored the hypothesis that patients suffering from dementia of the Alzheimer type (DAT) are particularly impaired in the functioning of the Central Executive component of working memory, and that this will be reflected in the capacity of patients to perform simultaneously two concurrent tasks. DAT patients, age-matched controls and young controls were required to combine performance on a tracking task with each of three concurrent tasks, articulatory suppression, simple reaction time to a tone and auditory digit span. The difficulty of the tracking task and length of digit sequence were both adjusted so as to equate performance across the three groups when the tasks were performed alone. When digit span or concurrent RT were combined with tracking, the deterioration in performance shown by the DAT patients was particularly marked.

Low-frequency positive-pressure ventilation with extracorporeal CO2 removal in severe acute respiratory failure.

Abstract: Forty-three patients were entered in an uncontrolled study designed to evaluate extracorporeal membrane lung support in severe acute respiratory failure of parenchymal origin. Most of the metabolic carbon dioxide production was cleared through a low-flow venovenous bypass. To avoid lung injury from conventional mechanical ventilation, the lungs were kept "at rest" (three to five breaths per minute) at a low peak airway pressure of 35 to 45 cm H2O (3.4 to 4.4 kPa). The entry criteria were based on gas exchange under standard ventilatory conditions (expected mortality rate, >90%). Lung function improved in thirty-one patients (72.8%), and 21 patients (48.8%) eventually survived. The mean time on bypass for the survivors was 5.4 ± 3.5 days. Improvement in lung function, when present, always occurred within 48 hours. Blood loss averaged 1800±850 mL/d. No major technical accidents occurred in more than 8000 hours of perfusion. Extracorporeal carbon dioxide removal with low-frequency ventilation proved a safe technique, and we suggest it as a valuable tool and an alternative to treating severe acute respiratory failure by conventional means. (JAMA1986;256:881-886)

Survival and prognostic indicators in compensated and decompensated cirrhosis.

Abstract: Six-year survival of cirrhosis was assessed in a series of 1155 consecutive patients (751 men, 404 women). Among the men, 33% were alcoholics and 18% were HBsAg positive; corresponding figures for the women were 15% and 6%, respectively. Features of decompensation at first presentation were observed in 63% of the patients. Six-year survival was 54% in compensated and 21% in decompensated patients. No significant differences in survival were found between alcoholics and nonalcoholics. Leading causes of death were liver failure (49%), hepatocellular carcinoma (22%), and bleeding (13%). The prognostic role of 21 variables was evaluated separately in compensated and decompensated patients by the Cox's regression model. The following variables were found to be significant predictors of death risk in compensated patients: male sex, HBsAg positivity, age, prothrombin time prolongation, and esophageal varices. In decompensated disease the significant indicators of death risk were: hepatocellular carcinoma, encephalopathy, hemorrhage, SGOT, esophageal varices, gamma globulins, prothrombin time prolongation, continued abuse of alcohol, HBsAg positivity, gamma glutamyl transpeptidase, and cholinesterase. A simple prognostic index based upon the relative risk coefficient of the significant variables is suggested.

Adult respiratory distress syndrome profiles by computed tomography

Abstract: Ten patients with full-blown ARDS, on mechanical ventilation with PEEP underwent lung CT. Seven normal subjects were also studied. Three tomographic levels (apex, hilum, and base) were selected. The most consistent morphologic finding in ARDS was the presence of densities in the dependent regions of the lung. Assuming that the three levels were a representative sample of the whole lung, the lung weight was computed from the mean CT number and lung gas volume. Analysis of the CT number frequency distribution revealed three definite patterns of distribution: type 1, bimodal, with one mode in the normal CT number range; type 2, unimodal narrow distribution, with the mode in the CT range of water; and type 3, unimodal broad distribution in the abnormal CT number range.

Characterization of single pacemaker channels in cardiac sino-atrial node cells

Abstract: Normal pacemaking in the mammalian heart is driven by spontaneously active cells located in the sino-atrial (SA) node. The rate of firing of these cells and the modulation of this rate by catecholamines are controlled by if, an inward Na- and K-current that turns on at voltages more negative than −40 mV1–9. The ‘pacemaker’ current if is also present in other types of cell where its ability to produce and modulate a depolarizing process may be useful10. For example, in vertebrate photoreceptors if drives the depolarization that terminates the light-induced hyperpolarization11. Currents similar to if are also found in hippocampal neurones and DRG neurones12,13. The present report shows for the first time that the opening of single if-channels of low conductance (1 pS) can be resolved using a modification of the patch-clamp technique14 on isolated SA-node cells. Modulation of if by adrenaline is shown to be mediated by an increase in the probability of channel opening, whereas the single-channel amplitude remains unchanged.

Arterial baroreflexes and blood pressure and heart rate variabilities in humans.

Abstract: The factors responsible for 24-hour blood pressure and heart rate variabilities have never been clarified; however, studies performed in unanesthetized animals have shown an increase in blood pressure variability after sinoaortic denervation, and a negative relationship has been reported occasionally between blood pressure variability and baroreflex control of heart rate in humans. We have systematically investigated this issue in 82 ambulant hypertensive subjects using 24-hour intraarterial blood pressure recording (Oxford method) in which blood pressure and heart rate variabilities were measured by calculating the standard deviations of the values obtained throughout the 24 hours or during separate daytime and nighttime periods. Baroreflex sensitivity was assessed by the bradycardic or tachycardic responses to intravenous injections of phenylephrine or nitroglycerin and by the blood pressure response to changes in carotid transmural pressure obtained with a neck chamber. The sensitivity of the baroreceptor-heart rate reflex as assessed by the vasoactive drug technique showed a negative relationship with 24-hour blood pressure variability as well as with daytime and nighttime blood pressure variabilities measured separately (r = -0.28 to -0.50, p less than 0.05). These variabilities also correlated negatively with the sensitivity of the baroreceptor-blood pressure reflex as assessed by the neck chamber technique. By contrast, baroreflex sensitivity showed a positive correlation with heart rate variabilities (r = 0.32 to 0.47, p less than 0.05). The relationship between baroreflex sensitivity and blood pressure and heart rate variabilities was confirmed when the data were analyzed by multiple regression to adjust for blood pressure and age differences among the 82 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Energetic cost of carrying loads: have African women discovered an economic way?

Abstract: When travelling in East Africa one is often surprised at the prodigious loads carried by the women of the area. It is not uncommon to see women of the Luo tribe carrying loads equivalent to 70% of their body mass balanced on the top of their heads (Fig. 1). Women of the Kikuyu tribe carry equally large loads supported by a strap across their foreheads; this frequently results in a permanently grooved skull. Recent experiments on running horses, humans, dogs and rats showed that the energy expended in carrying a load increased in direct proportion to the weight of the load for each animal at each speed, that is, carrying a load equal to 20% of body weight increased the rate of energy consumption by 20% (ref. 1). The purpose of the present study was to determine whether these African women use specialized mechanisms for carrying very large loads cheaply. We found that both the Luo and Kikuyu women could carry loads of up to 20% of their body weight without increasing their rate of energy consumption. For heavier loads there was a proportional increase in energy consumption, that is, a 30% load increased energy consumption by 10%, a 40% load by 20% and so on. We suggest that some element of training and/or anatomical change since childhood may allow these women to carry heavy loads economically.

The electronic structure of the benzene molecule

Abstract: The Kekule description of benzene as a mixture of the two structures and was given a firm foundation in quantum theory as a ‘resonance hybrid’ (see, for example, ref. 1). As molecular orbital (MO) theory developed, it was felt that the aromatic character of benzene was explained more naturally in terms of delocalized orbitais. The view that delocalized electrons provide essentially the correct description for this type of system appears to be accepted at all levels2; however, we present here theoretical evidence which challenges this view. We show that the π-electrons in benzene are almost certainly localized and that the characteristic properties of such a system arise from the mode of spin coupling.

An epidemiological study of psychic trauma and treatment effectiveness for children after a natural disaster.

Abstract: Approximately 300 Italian elementary school children who were victims of a devastating earthquake were surveyed in an epidemiological study. The measure used was the Rutter Behavioral Questionnaire for Completion by Teachers. In one village a treatment program was developed and implemented. A frequency count of the expressed earthquake-related fears and anxieties was taken during every treatment session. Treatment consisted of a gradual series of steps that led to a replaying of the earthquake. It was hypothesized that the number of children shown to be at risk for developing neurotic or antisocial problems would be positively correlated with the amount of destruction in a village. This was not verified. It was also hypothesized that treatment would reduce earthquake fears and the number of children at risk. This was verified. The village where treatment was carried out for 1 academic year showed a significant drop in the at-risk scores. Conclusions were that treatment alleviates symptoms but that the number of children at risk seems to be more related to the length of time needed for the community to reorganize after the disaster.

Morphological response to positive end expiratory pressure in acute respiratory failure. Computerized tomography study

Abstract: Ten patients with acute respiratory failure (ARF), (4 pneumonia, 4 sepsis, 2 polytrauma), underwent computerized tomography (CT) of the lungs, (apex, hilum, base), at 5, 10, 15 cm H2O positive end expiratory pressure (PEEP). The ARF lungs, on CT scan, appeared as a patchwork of normal and dense areas with generally well defined boundaries. Most of the densities were found in the dependent regions. The areas of density were correlated with PaO2 (r = 0.51). The PEEP increase resulted in a significant expansion of total cross-sectional lung surface area. The dense areas decreased significantly at the hilum and base when increasing PEEP while the changes at the apex were not significant. The changes of density with PEEP were highly correlated with the changes in oxygenation (r = 0.91). In the individual patient, however, the modifications of gas exchange can not be entirely predicted from morphological changes, possibly due to a diversion of pulmonary blood flow.

Conjugated estrogens for the management of bleeding associated with renal failure.

Abstract: Bleeding is a major complication of uremia. Both cryoprecipitate and desmopressin effectively shorten the prolonged bleeding time and favorably influence clinical bleeding, but the former carries the risk of transmitting blood-borne infectious diseases, and both cryoprecipitate and desmopressin have a short duration of action. Preliminary evidence has suggested that estrogens may be useful, and we therefore performed a randomized, double-blind, crossover trial comparing the effect of conjugated estrogens with that of placebo on hemorrhagic tendencies and the bleeding time in six patients with uremia who were on maintenance hemodialysis. Five daily infusions of placebo or conjugated estrogens were administered at the beginning of one-month trial periods. Estrogen shortened the bleeding time in all six patients. The effect was detectable six hours after the first infusion, reached its maximum in all patients between days 5 and 7, and lasted for 14 days. By day 16 after the last infusion, the bleeding time had returned to base line in four of the six patients. No side effects were noted during or after estrogen infusion. Estrogens did not influence the circulating level of von Willebrand factor or change its multimeric structure. Moreover, the defective platelet aggregation and thromboxane formation observed in the patients were not corrected by estrogens. We conclude that conjugated estrogens are an adequate alternative to cryoprecipitate or desmopressin for the treatment of bleeding associated with renal failure, especially when a longer duration of action is needed and immediate onset of the effect is not essential. The mechanism of action of estrogens remains to be clarified.

Effects of reversible renal denervation on haemodynamic and excretory functions of the ipsilateral and contralateral kidney in the cat

Abstract: In anaesthetized cats reversible denervation of one kidney was performed by cooling of the left renal nerves to 3 degrees C for 16 min. The response of the left (ipsilateral) kidney was compared with the response of the right (contralateral) kidney twice in the same animal: (1) when the right kidney was still innervated, and (2) after it had been surgically denervated. Left renal nerve cooling did not cause any changes in arterial pressure. In the left kidney, blood flow, vascular conductance, sodium and water excretions increased, and renin release decreased. Simultaneously in the contralateral kidney, no haemodynamic changes were observed, glomerular filtration was only transiently decreased, whereas sodium and water excretion significantly decreased and renin release increased. When left renal nerve cooling was repeated after surgical denervation of the right kidney, similar changes were observed in the left (ipsilateral) kidney, whereas all contralateral effects were abolished. These experiments suggest that tonically active afferent fibres from one kidney exert a reflex inhibitory action on sympathetic activity directed to the contralateral kidney controlling tubular sodium reabsorption and renin release.

Cutaneous lesions in 67 cyclosporin-treated renal transplant recipients.

Abstract: Sixty-seven out of 100 kidney transplant recipients treated with cyclosporin and methylprednisolone were evaluated for the presence of dermatological manifestations. Only 2 patients had no dermatological lesions; 80% had iatrogenic lesions, 38% infectious, 13% miscellaneous, 3% cancerous lesions, while 28% had cutaneous manifestations related to previous uremic state. Most of the lesions concerned the pilosebaceous unit: hypertrichosis (60%), epidermal cysts (28%), pilar keratosis (21%), acne (15%), folliculitis (12%) and sebaceous hyperplasia (10%). Among infectious manifestations, viral lesions were the most frequent and were very severe in the first month after transplantation. Two patients developed a squamous-cell epithelioma and a probable cutaneous lymphoma, respectively.

Wheat inoculation with Azospirillum brasilense Sp6 and some mutants altered in nitrogen fixation and indole-3-acetic acid production

Abstract: Inoculation of wheat seedlings with Azospirillum brasilense Sp6 produced an increase in the number and length of the lateral roots as a plant response. Inoculation with a Nif− mutant, A. brasilense SpF103, which is producer of indole-3-acetic acid (IAA), yielded a very similar plant response. However, inoculation with a Nif− mutant, A. brasilense SpF57, which is a low producer of IAA, did not elitic any response from the plant. The data suggest that the root system response of wheat seedlings to bacterial inoculation is due mainly to production of auxin-type substances by the microorganism.

Static Behavior of the Respiratory System

Abstract: The sections in this article are: 1 Lung Volumes 2 Volume-Pressure Relations of Respiratory System During Relaxation 2.1 Total Respiratory System 2.2 Chest Wall and Lung 2.3 Effects of Gravity and Posture 2.4 Changes Throughout Life Span 3 Volume-Pressure Relations of Respiratory System During Static Muscular Efforts 3.1 Alveolar Pressure 3.2 Abdominal and Thoracic Pressures 4 Factors Limiting Volume Extremes 4.1 Upper Volume Extreme 4.2 Lower Volume Extreme

Binding of fibrinogen to human monocytes.

Abstract: The interaction of fibrinogen with monocytes was studied. After stimulation with ADP (10 microM) or thrombin (1 U/ml), platelet-free suspensions of human monocytes bind 125I-fibrinogen with two different affinities in a specific and Ca2+-dependent reaction with saturation at 5.80-7.35 X 10(-7) M of added protein. The binding of fibrinogen to specific receptors on monocytes induces the procoagulant activity of these cells. Thrombasthenic cells or normal monocytes preincubated with a monoclonal antibody to the platelet glycoprotein IIb/IIIa complex (10E5) do not bind fibrinogen and have no procoagulant activity. Metabolic studies with [35S]methionine revealed that cultured monocytes actually synthesize a surface antigen precipitated by 10E5 antibody as a major band with 92,000 relative molecular weight. Our data indicate that monocytes express receptors for fibrinogen only in part related to the platelet glycoprotein IIb/IIIa complex. Furthermore, the binding of fibrinogen to monocytes enhances the cooperation of these cells in hemostasis.

Modulation of the Hoffmann reflex by rapid muscle contraction or release

Abstract: The inhibition of the H-reflex of the Soleus (Sol) muscle that takes place during and after voluntary release of Sol muscle has been attributed to presynaptic inhibition of autogenetic spindle afferences. In the present study, the time-relationship between onset of H-reflex depression and termination of Sol contraction was investigated to ascertain whether the reflex inhibition is linked to the command to release, or whether it is an accompanying phenomenon connected to changes in the neural outflow from the periphery. A parallel investigation was carried out on the temporal characteristics of the facilitation of the H-reflex that precedes onset of Sol contraction, in an attempt to point at the different functional organization of the two motor tasks. Voluntary releases from a bilateral isometric plantar torque, or bilateral plantar flexions, were performed in response to an acoustic stimulus, in a reaction time (RT) situation. The intervals from the starting signal to complete termination, or to beginning, of the Sol EMG were measured. The H-reflex was evoked at random during the tasks in one leg and its amplitude was referred in time to the end, or to the onset, of the EMG recorded from the contralateral Sol muscle. The RTs of the termination of Sol EMG had an average duration of about 100 ms, being some 20 ms shorter than those of the onset of EMG. In the release-task, the H-reflex amplitude was higher than that of the controls during the holding phase, and started to decrease about 20 ms before the cessation of the EMG.(ABSTRACT TRUNCATED AT 250 WORDS)

Sexual factors, venereal diseases, and the risk of intraepithelial and invasive cervical neoplasia.

Abstract: The relation between major indicators of sexual habits (age at first intercourse and total number of sexual partners), history of selected venereal diseases, and cervical neoplasia was investigated using data from a case-control study of 206 cases of cervical intraepithelial neoplasia compared with 206 age-matched outpatient controls, and of 327 cases of invasive cancer compared with 327 control subjects in hospital for acute conditions unrelated to any of the established or suspected risk factors for cervical cancer The relative risks increased with decreasing age at first intercourse and increasing number of sexual partners both for intraepithelial and for invasive cancers The effects of these two variables were independent, since they were only marginally affected by reciprocal adjustment, or by allowance for several other identified potential distorting factors The negative association with age at first intercourse was particularly strong in the case of invasive cancers, with risk estimates over five-fold elevated for women reporting their first intercourse before age 18 compared with those aged over 22 years This relation might be discussed in terms of multistage models of carcinogenesis, which predict that the incidence of epithelial carcinomas is a function of duration of exposure In fact, when age was allowed for, the relative risks of cervical neoplasia were positively and strongly related with the total duration of the interval between age at diagnosis/interview and age at first intercourse Clinical histories of several sexually transmitted diseases were positively associated with the risk of intraepithelial neoplasia In particular, genital warts were reported by nine cases but no control subject No such association, however, emerged for invasive carcinomas Thus, the current findings confirm that, although intraepithelial neoplasia and invasive cervical cancer appear to share several important epidemiological features, the specific (infectious) agents implicated in dysplastic lesions probably differ to some extent from those causing invasive cancer

Nutrition and diet in the etiology of endometrial cancer.

Abstract: The risk of endometrial cancer in relation to nutrition and frequency of consumption of a few selected dietary items was evaluated id a case-control study of 206 patients with endometrial cancer and 206 control subjects with acute conditions unrelated to any of the established or potential risk factors for endometrial cancer. Obesity was strongly and positively associated with the risk of endometrial cancer, and several conditions related to body weight, such as early menarche, diabetes mellitus, or hypertension were more common in cases. The risk of endornetrial cancer was elevated in subjects reporting (on a subjective basis) greater fat (butter, margarine, and oil) intake (relative risk estimate for the higher compared to the lower scores equals 5.65, with 95% confidence interval of 2.76-11.55). Cases reported less frequent intake of green vegetables, fruit, and whole-grain foods: thus, the risk of endometrial cancer appeared inversely related to indices of beta-carotene and fiber intake. Furthermore, cases consumed milk, liver and fish less frequently than controls. No significant difference was noted between cases and controls in the frequency of intake of carrots, meat, eggs, ham, and cheese. Alcohol consumption WBS somewhat larger among the cases, but this trend in risk was not significant. Dietary information collected in this study probably is too limited and inconsistent to permit analysis of biologic correlates of these findings or discussion of their potential implications in terms of prevention on a public health scale. Nonetheless, the mere existence of differences in reported diet between endometrial cancer cases and controls is of interest, and may warrant further, more detailed investigation. Cancer 57:1248-1253, 1986. HERE IS a persuasive body of evidence that endoT metrial cancer is associated with body weight, as it occurs considerably more frequently in obese women.’ This is commonly explained in terms of increased aromatization of androgens to estrogens in adipose tissue, which is the major source of estrogens in postmenopausal women.2 The relation between body weight and endometrial cancer risk, however, is similarly evident in premenopausal women as well when circulating estrogens are chiefly ovarian in 0rigin.~9~ The link between nutrition and endometrial cancer, therefore, may be more complex, including the importance of sex hormone-binding globulins or the composition itself of adipose tissue, and potentially mediated through specific dietary components.