The HSPB1-p62/SQSTM1 functional complex regulates the unconventional secretion and transcellular spreading of the HD-associated mutant huntingtin protein.

Conformational diseases, such as Alzheimer, Parkinson and Huntington diseases, are part of a common class of neurological disorders characterized by the aggregation and progressive accumulation of proteins bearing aberrant conformations. Huntington disease (HD) has autosomal dominant inheritance and is caused by mutations leading to an abnormal expansion in the polyglutamine (polyQ) tract of the huntingtin (HTT) protein, leading to the formation of HTT inclusion bodies in neurons of affected patients. Interestingly, recent experimental evidence is challenging the conventional view by which the disease pathogenesis is solely a consequence of the intracellular accumulation of mutant protein aggregates. These studies reveal that transcellular transfer of mutated huntingtin protein is able to seed oligomers involving even the wild-type (WT) forms of the protein. To date, there is still no successful strategy to treat HD. Here, we describe a novel functional role for the HSPB1-p62/SQSTM1 complex, which acts as a cargo loading platform, allowing the unconventional secretion of mutant HTT by extracellular vesicles. HSPB1 interacts preferentially with polyQ-expanded HTT compared with the WT protein and affects its aggregation. Furthermore, HSPB1 levels correlate with the rate of mutant HTT secretion, which is controlled by the activity of the PI3K/AKT/mTOR signalling pathway. Finally, we show that these HTT-containing vesicular structures are biologically active and able to be internalized by recipient cells, therefore providing an additional mechanism to explain the prion-like spreading properties of mutant HTT. These findings might also have implications for the turn-over of other disease-associated, aggregation-prone proteins.

MMP-2, MMP-9, VEGF and CA 15.3 in breast cancer.

BACKGROUND: Matrix metalloproteinases (MMPs) are a family of extracellular matrix degrading proteinases. Owing to their matrix-degrading abilities and high expression in advanced tumours, MMPs were originally implicated in cancer progression, invasion and metastasis. PATIENTS AND METHODS: In this study, the correlation was determined between the expression of gelatinases (MMP-2 and MMP-9) in the sera of breast cancer patients from zymographic analysis and serum concentrations of VEGF and CA 15.3, before surgery and after 1 and 6 months; the association of both markers with clinicopathological features including histological type, stage of disease and estrogen (ER) and progesterone (PgR) receptors status were also analysed. In all, 88 breast cancer patients and 20 healthy women were involved in this study. RESULTS: No statistically significant correlation between pro MMP-2, pro MMP-9, VEGF and CA 15.3 serum levels was found (p>0.05). In breast cancer patients, a significant decrease of the pro MMP-2 serum expression 1 month after surgery with respect to serum levels before surgery (p=0.0008) was evident, as well as of CA 15.3 serum levels at baseline and after 1 month (p=0.017). Moreover a strong decrease of pro MMP-9 serum levels was found in 88 breast cancer patients after 1 month (p=0.028) and after 6 months (p =0.009) from surgery. On the other hand, no significant differences in the serum levels of VEGF, CA 15.3, pro MMP-2 or pro MMP-9 between 88 breast cancer patients preoperatively and 20 healthy women as controls were found. Our findings did indicate a significant positive association between higher preoperative levels of CA 15.3 and progression of disease (p=0.03), as well as a longer disease-free survival in patients who exhibited a decrease of serum pro MMP-9 expression compared to other biomarkers. No relationship between these four markers and the main clinical and pathological parameters was found. CONCLUSION: The present study failed to demonstrate any association between serum levels of MMPs, VEGF and CA 15.3 and well-known clinicopathological characteristics of breast carcinoma, while demonstrating the prognostic value of CA 15.3 and pro MMP-9 in the follow-up of breast cancer patients.

Calcium antagonists in the therapy of acute myocardial infarction.

The theoretical background and experimental evidence of the use of calcium antagonists in the treatment of acute myocardial infarction are summarised. The main clinical trials that have studied the effects of the three different groups of these drugs in patients with myocardial necrosis are then reviewed. Finally, the conclusion is drawn that there is no proof of the efficacy of calcium blockers in the therapy of patients with acute myocardial infarction but that, in some subgroups of these subjects (Q-wave myocardial infarction with good left ventricular function, non Q-wave myocardial infarction), non-dihydropyridinic compounds should be effective, in particular in patients with contraindications to beta-adrenergic blockade.

Summer camps for diabetic children: an experience in Campania, Italy.

To evaluate the effectiveness of summer camps with objective parameters, the authors examined data relative to nine summer camps organized by the Young Diabetics Association in Campania, Italy. The mean duration of camps was 10 days (range, 8-15) and a total of 256 diabetic children with an average age of 10 (range 8-16) participated in them. The medical personnel consisted of three pediatric endocrinologists, one psychologist, two male nurses and two parents who were directors of the Association. A significant improvement in knowledge and self-management of the disease was noted at the end of the camps. A beneficial effect on mean HbA1c level was also observed in the diabetic children who attended the monthly meetings and follow-up checks with their parents after the camp. On the other hand, a worsening of these values was noted in diabetic children who did not participate in them. No increased incidence of hypoglycaemia or ketoacidosis was found during or after camps, in contrast with previous studies. From a psychological viewpoint, the results suggest that summer camps have an important bearing on achieving acceptance of the disease. Sharing personal experiences with actively involved parents who participated in self-management training together with their children, has favourably influenced the results of this experience in Campania.

Surgical treatment of late neurological deterioration in children with myelodysplasia.

Late deterioration of the neurological condition in patients operated on for myelomeningocele repair has been repeatedly reported in the literature. At the present time magnetic resonance imaging (MRI) allows one to recognize various pathological conditions which can be amenable to surgical correction in these patients, such as Chiari type II malformation, hydro/syringomyelia, decompensated hydrocephalus, and tethered spinal cord. The authors report their experience with 26 myelodysplastic children operated on for myelomeningocele repair in the early neonatal period, who exhibited late deterioration at variable time intervals from the first operation. The children were examined pre-operatively by means of MRI; the results were compared with those provided by MRI in 46 myelodysplastic children who underwent the investigation as a routine follow-up control. The MRI findings were subdivided into 4 main groups of increasing severity from 1 to 4; in some subjects, associated pathological conditions (Chiari II malformation, hydromyelia, etc.) were detected as well. Twenty-two out of the 26 patients with late neurological deterioration were operated on. Eleven of them (grades 2 to 4) underwent detethering of the fixed conus, with an improvement of their clinical picture from mild to good. On the other hand the remaining 11 subjects (grades 1 to 2) improved their condition following the correction of the associated abnormalities (malfunctioning CSF shunt: 5 cases; hydromyelia: 4 cases; symptomatic Chiari II malformation: 2 cases).

The cardiopulmonary response to incremental exercise test: the effect of aging.

The aims of the present study were to define the respective roles of the cardiac and respiratory response to exercise as determinants of the age-related physiological decrease in exercise performance, and to assess the relationship between aging and interindividual variability in the response to effort. We studied 91 normal subjects recruited in three age-groups: Group A (42 children, aged 10 +/- 2 years); Group B (29 young adults, aged 27 +/- 5 years); Group C (20 elderly, aged 74 +/- 9 years). All the subjects underwent an incremental cycle ergometer exercise test with a work load increase of 15 W every 2 minutes in groups A and C, and 25 W every 2 minutes in group B, until they achieved 80% of the predicted maximal heart rate. Ventilatory equivalent changes during exercise were significantly lower in group A than in the other two groups, and in group B compared to group C. Exercise-induced changes in oxygen pulse were significantly higher in group A, but no difference was found between groups B and C. Thus, gas-exchange function and overall exercise performance decrease with advancing age, whereas cardiovascular performance is well maintained in normal elderly subjects. Discriminant analysis showed that the exercise response conformed to the group-specific model in 74% and 79% of subjects in groups A and B, but only in 50% of the group C subjects; 5% and 45% of the elderly subjects were functionally classified in groups A and B, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiarrhythmic effect of L-propionylcarnitine in isolated cardiac preparations.

The effects of L-propionylcarnitine on reperfusion-induced ventricular arrhythmias were studied in isolated hearts from spontaneously hypertensive rats. During reperfusion, 60% (n = 15) of the hearts from control spontaneously hypertensive rats hearts developed irreversible ventricular fibrillation. In contrast, irreversible ventricular fibrillation did not occur in hearts from normotensive Wistar Kyoto rats (n = 11, p less than 0.01). In a second group of spontaneously hypertensive rats, the addition of 10(-6) M L-propionylcarnitine to the medium during ischemia and reperfusion reduced the incidence of irreversible ventricular fibrillation to 14% (n = 14, p less than 0.05 versus control spontaneously hypertensive rats, NS versus Wistar Kyoto rats). Concentrations of L-propionylcarnitine from 10(-6) to 10(-2) M were tested on isolated guinea pig papillary muscles using microelectrodes. Resting potential, action potential amplitude, action potential duration and active tension were not modified by L-propionylcarnitine; and 10(-3) M L-propionylcarnitine did not influence the oscillatory afterpotentials induced by digitalis. We conclude that reperfusion ventricular arrhythmias are more severe in spontaneously hypertensive rats than in Wistar Kyoto rats and that the antiarrhythmic effect of L-propionylcarnitine in spontaneously hypertensive rats is mediated by myocardial protection from damage induced by reperfusion.

Possible sources of iron for lipid peroxidation.

Possible sources of iron for lipid peroxidation are described and discussed. In particular, evidence is presented that microsomes contain ferric nonheme iron which may participate in formation of lipid oxidants, provided reductants are available to favor its mobilization from membrane binding sites. Aging- and tumor-associated changes of this microsomal pool of nonheme iron are also described and discussed from biochemical and biomedical viewpoints.

Microsomal iron-dependent NADPH oxidation: evidence for the involvement of membrane-bound nonheme iron in NADPH oxidation by rat heart microsomes.

Rat heart microsomes were found to contain nonheme iron and two lines of evidence suggested that this iron was involved in NADPH oxidation. As first evidence, pretreatment of rats with iron gluconate increased microsomal iron content and NADPH oxidation. As second evidence, treatment of microsomes with nonionic detergent Triton N-101 decreased membrane iron content and NADPH oxidation. Triton N-101-solubilized nonheme iron was nondialyzable and ammonium sulfate-precipitable, indicative of association with protein(s). This protein-bound iron per se did not oxidize NADPH but its addition to detergent-treated microsomes restored very high rates of NADPH oxidation, that were abolished by inhibiting NADPH-cytochrome P450 reductase with p-hydroxymercuribenzoate. Since heart microsomes did not contain cytochrome P450, these results suggested that stimulation of NADPH oxidation was mediated by direct electron transfer from reductase to iron. Purified rat heart ferritin and hemosiderin did not stimulate NADPH oxidation and the stimulation observed with detergent-solubilized microsomal iron was much higher than that observed with EDTA-Fe3+, a very effective electron acceptor for the reductase. This suggested that (i) microsomal iron was different from other intracellular iron-storage proteins, and (ii) microsomal iron was unusually permissive to one-electron transfer from reductase.

Increased propensity of the aged myocardium to develop calcium-related electrophysiological alterations.

The electrico-mechanical effects of calcium overload have been studied in cardiac papillary muscles of young adult and senescent Wistar rats driven at different rates. Action potential duration and contraction duration were found to be more prolonged in senescent than in younger animals during control conditions. Oscillatory afterpotentials and aftercontractions were more frequent in senescent than in younger rats during high calcium perfusion. Triggered activity was induced in senescent fibers but not in younger ones. Resting tension increased more in senescent fibers whereas the peak tension was not different in the two groups. It is concluded that aging is associated with a reduced capacity of the cardiac cells to handle an increased calcium load.

Cardiac aging, calcium overload, and arrhythmias.

The effect of aging was tested on experimental ventricular arrhythmias in isolated heart preparations from normal Wistar rats (NWR), Wistar Kyoto rats (WKY), and spontaneously hypertensive rats (SHR). Delayed afterdepolarizations and triggered activity induced by high-calcium perfusion (16 mM) in isolated papillary muscles were more frequent in the 24-month-old than in 6-month-old NWR. Reperfusion-VA were more severe in 14-month-old SHR than in WKY. The authors have previously shown that: (1) reperfusion- and reoxygenation-induced VA, in the isolated Langendorff perfused heart, were significantly more severe and frequent in 24-month-old than in 6-month-old NWR; (2) no age-related difference in the incidence of programmed electrical stimulation (PES, train of stimuli + 1 or 2 extrastimuli)-induced VA was observed in isolated NWR hearts during control perfusion, after coronary artery ligation or during hypoxia; (3) on the contrary, the incidence of PES-induced VA was significantly higher in isolated hearts from 14-month-old SHR than from 3-month-old SHR, and 3-month-old and 14-month-old WKY. It was concluded that "physiological" aging is associated with a higher propensity to calcium-related VA, while "pathological" aging characterized by hypertension of long duration increases the incidence of PES-induced VA, probably caused by myocardial fibrosis, which could facilitate reentry.

Programmed electrical stimulation-induced arrhythmias in isolated hearts from adult and senescent rats.

In isolated hearts from normal rats, we previously demonstrated an age-related increase of spontaneous ventricular arrhythmias. The aim of the present experiments was to test the possible effect of aging on ventricular arrhythmias induced by programmed electrical stimulation. Experiments were performed in isolated cardiac preparations of 6- and 24-month-old normal Wistar rat hearts. Programmed electrical stimulation (single or double premature stimuli following a stimuli train) was tested in isolated Langendorff perfused hearts during control perfusion, after left anterior descending coronary artery ligature and during global hypoxia. No significant differences were observed between adult and senescent hearts in the incidence of programmed electrical stimulation-induced ventricular arrhythmias during these three different situations. These experiments demonstrate that the cardiac "physiological" aging process is not associated with a greater propensity to programmed electrical stimulation-induced arrhythmias.

Age-related increase in the incidence of ventricular arrhythmias in isolated hearts from spontaneously hypertensive rats.

In order to test the effect of arterial hypertension on cardiac electrical activity, isolated Langendorff perfused hearts from spontaneously hypertensive (SHR) and normotensive (WKY) rats were studied. The incidence of spontaneous ventricular arrhythmias occurring during the control perfusion was 0% (n = 28) in WKY, 31% in SHR (n = 29, p less than 0.01), 7% (n = 14) in 3-month-old SHR, and 53% in 14-month-old SHR (n = 15, p less than 0.05). The incidence of ventricular arrhythmias induced by programmed electrical stimulation (PES = stimulus train + two extrastimuli) was 18% in WKY (n = 28), 48% in SHR (n = 27, p less than 0.05), 29% (n = 14) in 3-month-old SHR, and 69% (n = 13) in 14-month-old SHR (p less than 0.05). The incidence of PES-induced irreversible ventricular fibrillation was 0% in WKY and in 3-month-old SHR (n = 42), whereas it was 38% (n = 13) in 14-month-old SHR (p less than 0.001). Myocardial norepinephrine was significantly reduced in SHR with respect to WKY, but no significant difference was observed between 3-month-old SHR and 14-month-old SHR. Thus, no correlation between myocardial norepinephrine and ventricular arrhythmias could be found. It was concluded that the duration of hypertension was the most important factor in the development of severe ventricular arrhythmias.

Electrical and ionic mechanisms of early reperfusion arrhythmias in sheep cardiac Purkinje's fibers.

The mechanisms of induction of early reperfusion arrhythmias were studied in sheep cardiac Purkinje's fibers superfused in vitro. Transmembrane potentials, intracellular sodium activity (aiNa), and contractile force were recorded. Stoppage of the flow of Tyrode's solution (ischemia) for 1 hour initially decreased slightly aiNa (-0.57 mmol -7.2%), increased the action potential amplitude (+6.1%) and duration (+7.8%), and decreased diastolic depolarization slope (-45.2%). As the ischemia continued, aiNa increased progressively (to 12.53 mmol, +56.2%), whereas force peaked (+395%) after about 30 minutes and then began to decrease. By the end of ischemia, there was a decrease in action potential amplitude (-14.9%) and duration (-39.6%), whereas diastolic depolarization slope reincreased again almost to control value (-7%). When the flow of Tyrode's solution was resumed (reperfusion), force markedly increased (+211.1%) and oscillatory potentials initiated arrhythmias (extrasystoles and repetitive fast discharge) in 64% of tests. Force and aiNa decreased relatively rapidly. The arrhythmias initiated after 58.4 +/- 1.8 seconds of reperfusion and lasted 101.5 +/- 3.2 seconds. When [Na]o was increased by +19.2%, reperfusion arrhythmias occurred after only 30 minutes of ischemia. Thus, in Purkinje's fibers superfused in vitro, early reperfusion arrhythmias are induced by oscillatory potentials caused by calcium overload, which is enhanced by the increase in aiNa during ischemia.

An outbreak of cholera in a refugee camp in Africa.

A total of 541 cases of cholera were observed between May 7 and July 19, 1985 among the 9,929 displaced persons present in a refugee camp in Africa. In spite of malnutrition and other diseases affecting this population, only 12 deaths occurred. Antiepidemic measures consisted of preparation of isolation-wards, treatment of contaminated materials, training of refugees and patient care. Mass prophylaxis, initially considered, was dropped before the end of the epidemic.

An outbreak of cholera in a refugee camp in Africa

A total of 541 cases of cholera were observed between May 7 and July 19, 1985 among the 9,929 displaced persons present in a refugee camp in Africa. In spite of malnutrition and other diseases affecting this population, only 12 deaths occurred. Antiepidemic measures consisted of preparation of isolation-wards, treatment of contaminated materials, training of refugees and patient care. Mass prophylaxis, initially considered, was dropped before the end of the epidemic(AU)

Induction of overdrive excitation in the sinoatrial node in the presence of caffeine.

The induction of spontaneous repetitive activity by a drive ('overdrive excitation') was studied in the sinoatrial node of the guinea pig by recording electrical and mechanical activity in sinoatrial preparations made quiescent by exposure to 20 mM caffeine of caffeine plus high [Ca]0. Electrical drive induced action potentials that were followed by oscillatory potentials and simultaneous aftercontractions. The oscillatory potentials (and the associated aftercontractions) increased in magnitude with successive action potentials, thereby initiating spontaneous beats during slow drives or after fast drives. The repetitive activity eventually slowed and ceased abruptly as the oscillatory potential failed to attain the threshold. Overdrive induced oscillatory potential and aftercontractions even when it did not initiate spontaneous activity. These results suggest that in the presence of caffeine calcium overload can occur in the sinoatrial node and result in oscillatory potentials and abnormal automaticity.

Age-related differences in isolated rat sinus node function.

In order to rule out age-related differences in the sinus node (SN) function, the effects of different substances were tested in SN isolated preparations from adult (4-5-month-old) and old (24-25-month-old) rats. No difference was seen in the in vivo heart rate between adult and old rats, whereas sinus node rate (SNR) was significantly lower in the old rather than in the adult preparations. The effects of acetylcholine (10(-9)-10(-5) M) were similar between the two groups of preparations. The response to adenosine (10(-9)-10(-4) M) was significantly higher in the adult than in the old preparations (p less than 0.05). No significant difference was noted in the response to isoproterenol (10(-10)-10(-6) M). High calcium (5.4-8.1 mM) caused an increase of the SNR that was significantly greater in the old than in the adult preparations (p less than 0.005). In conclusion, our results show an age-related decrease in the isolated SNR that does not seem to be mediated by different responses to neuromediators but is probably due to an alteration of the intrinsic activity of the SN cells.