Biomedical subjects
Publications and source records attributed to S Ciaroni.
We present, with echocardiographic and intraoperative findings, a rare case of left ventricular-to-right atrial communication (Gerbode defect) after endocarditis associated with Staphylococcus aureus. (Tex Heart Inst J 1995;22:100-2)
The number and morphometric characteristics of sciatic sensory neurons were studied in Vitamin-E-deficient rats. Horseradish peroxidase (HRP) was injected into the sciatic nerves of normal and vitamin-E-deficient rats of the same age, and retrogradely labeled sensory neurons were counted and measured. The study was also carried out in rats that had previously undergone sciatic nerve crush, in order to observe the effects of axotomy on primary sensory neurons. In vitamin-E-deficient rats the number of sciatic sensory neurons was significantly higher than normal, with an increase of about 30%, in agreement with a previous finding concerning total population of primary sensory neurons in lumbar dorsal root ganglia (DRGs) of vitamin-E-deficient rats. The increase involved the small cell classes in particular. Axotomy induced similar percentages of neuron loss in normal and in vitamin-E-deficient rats (about 40%). In the latter, death affected small cell classes in particular--that is, the same classes that had increased in number in vitamin-E-deficient rats by comparison with controls. These results, together with previous findings, suggest that neurogenesis may occur in DRGs of vitamin-E-deficient rats.
Early exercise testing (EET) after acute myocardial infarction (MI) is a well-established means of detecting patients at high risk for subsequent cardiac events. However, the value of this test is not well documented in elderly patients. We evaluated the clinical and prognostic significance of EET in 188 patients, aged 70 years or more, 14 +/- 3 days after an uncomplicated acute MI. The mean follow-up period was 3.6 years (range 1 to 6 years) in 95% of the patients. The total mortality rate was 13.5% (24/178) and the cardiac-related mortality rate was 7.8% (14/178), with 64% of the deaths occurring in the first 3 years. There were no complications during EET. The following parameters measured during EET on a bicycle ergometer were predictive of subsequent cardiac death: an increase in systolic blood pressure of less than 30 mm Hg (p < 0.001), an increase in the double product of less than 12,500 mm Hg.beats/min (p < 0.001), a maximal load less than 60 W (p < 0.001), and a total duration of exercise less than 5 minutes (p < 0.001). The combination of these four parameters increased the predictive value of the test (p < 0.0001). ST segment depression and ventricular arrhythmias during exercise were not correlated with the incidence of subsequent cardiac death, but the degree of ST segment depression was directly and significantly (p < 0.0001) associated with the incidence of subsequent nonlethal cardiac events (coronary bypass surgery, coronary angioplasty, reinfarction, or unstable angina).(ABSTRACT TRUNCATED AT 250 WORDS)
The increased number of poly-innervated cells in normal and reinnervated extensor digitorum longus (edl) muscle of vitamin E-deficient rats suggests enhanced sprouting by motor neurons in conditions of decreased protection against lipid peroxidation. End-plates and terminal axons were observed by a combined technique that shows both end-plate acetylcholinesterase area and axons. Quantitative observations of nodal and terminal sprouting in normally innervated and reinnervated edl muscles of vitamin E-deficient rats were carried out. Branch points of nerve terminal within end-plates were also observed. Three main results were obtained. First, a notable increase of both terminal and nodal sprouting was found in reinnervated muscles of normal and vitamin E-deficient rats; moreover, a relative increase in the number of nodal sprouts occurs in the long run. Second, in muscles of uninjured, vitamin E-deficient rats, nodal and terminal sprouting and branching within end-plate was greater than in controls. Third, nodal sprouting by regenerating axons was more affected by vitamin E-deficiency than terminal sprouting and branching within end-plates.
Quantitative and morphometric observations were carried out on neurons of L3-L6 dorsal root ganglia (DRGs) in control and vitamin-E-deficient rats at different ages. Controls were fed a standard diet and sacrificed at 1 or at 5 months of age; deficient rats were fed a diet without vitamin E from 1 to 5 months of age and then sacrificed. No significant difference in total number of neurons was found, but an increase in neuron sizes, a decrease in nucleus-cytoplasm ratio, and a more circular neuron shape were found in controls with increasing age (from 1 to 5 months). In L3-L6 DRGs of vitamin-E-deficient rats (5 months of age), a higher number of neurons was found than in those of either young or adult controls. Moreover, some morphometric characteristics of neurons in the deficient rats were similar to those of neurons in 1-month-old controls. The findings suggest that vitamin E deficiency can trigger events resulting in appearance of new neurons, possibly anticipating phenomena that normally occur in aging.
Morphological analysis was performed on the adrenal cortex of depressed mice which received repeated administrations of Ginseng extract or Ginsenoside Rb1 or Ginsenoside Rg1 in order to follow the behaviour of the gland. The left gland was fixed for usual stains and cell measurements of both treated and control adrenal cortex were made on twenty central sections. The outlines of cells from the zona fasciculata, in which nucleus was evident, were traced at 625X using a drawing tube. Cell areas were computed from these drawings by means of image analysis (Optilab software). Our results show that: 1) Ginseng extract administration produces a significant increase in the zona fasciculata cell size with respect to controls. The distribution of soma sizes is generally to the right of the spectrum showing a considerable decrease in cells of small size and a similar increase in cells of intermediate and large size with respect to controls; 2) in Ginsenoside-administered animals, although the mean cell areas is not significantly altered, the distribution of cell sizes shows significant differences between normal and treated animals. It is commonly recognized that mean cell area is in strict connection with cell activity: therefore Ginseng extract may be thought to stimulate adrenal cell activity while the two Ginsenosides have an effect which do not lead to significant changes in mean cell size.
Forty-six patients with idiopathic or lone atrial fibrillation (AF) underwent clinical evaluation in the cardiology outpatient department. The follow-up period was 4.6 +/- 2.5 years. The prevalence of idiopathic AF was 19% (89% paroxysmal and 11% permanent) in a population of 244 patients with atrial fibrillation. The global prevalence was 1.15% out of 4,000 patients examined over the same period. A history of paroxysmal atrial fibrillation over a 6 +/- 4 year period was obtained in 61% of the patients with idiopathic AF before the study. At inclusion, 24% of patients were asymptomatic. During follow-up, 12 patients (26%) developed cardiovascular disease and/or hypertension. The size of the left atrium was measured by echocardiography in 45 patients and reevaluated in 30 of them during follow-up without any statistically significant difference being observed between the two values. There were no thromboembolic complications or deaths during follow-up. These results show that idiopathic AF is not uncommon in cardiology clinics. The evolution of the paroxysmal forms is variable--but the medium-term prognosis is excellent. In some cases, idiopathic AF may be a manifestation of asymptomatic coronary artery disease but the relationship between the two pathologies has not been definitely established.
Muscle reinnervation after nerve crush was observed in rats at different ages with a combined technique that simultaneously demonstrates nerve endings and endplates. At early times of reinnervation the amount of sprouting was higher in older rats than in younger rats; according to this finding an enhanced number of polyinnervated endplates was found in older rats. A similar enhancement of sprouting and polyinnervation was observed during muscle reinnervation of vitamin E deficient rats, supporting the proposed analogy between vitamin E deficiency and aging.
In this study we examined the changes in cortical layers when Methylazoxymethanol-acetate (MAM) was injected on 13th, 15th and 17th day of gestation (MAM13, MAM15, MAM17). Prenatal MAM administration prevents neuron precursor proliferation; the subsequent cell number decrease is followed by an increase in size of surviving cells. When MAM was injected on 13th or 15th day of gestation the significant decrease in cell density, in II and III zone (MAM13) and in the upper layers (MAM15), was compensated by a proportional increase in cell size and synaptic density. When MAM was injected on 17th embryonal day it did not cause a significant change in the neuron density and soma size was not altered while the distribution of cell size among layers showed significant differences with respect to the controls. Our findings of some area and synaptic density show that the cell surface increase is proportional to the decrease in cell number and that in the surviving cells there is a rearrangement in synaptic connections that compensate for the cellular density decrease.
Ventricular late potentials are strong predictors of arrhythmic events after acute myocardial infarction (AMI). To assess the effect of intravenous thrombolysis on the incidence of ventricular late potentials, 223 consecutive patients surviving a first AMI were included in the present study: 59 patients (53 men, 6 women, mean age +/- standard deviation 55 +/- 10 years) received intravenous recombinant tissue-type plasminogen activator (100 mg over 3 hours, group A) and 164 patients (123 men, 41 women, mean age 61 +/- 11 years) received conventional medical treatment (group B). A time-domain signal-averaged electrocardiogram and a high-resolution beat-to-beat recording (gain 10(6), filters 100 to 300 Hz) were performed at 10 +/- 3 days after AMI. There was no difference between group A and B patients in terms of AMI location (anterior in 28 of 59 vs 80 of 164, difference not significant [NS]), mean left ventricular ejection fraction (55 +/- 10 vs 55 +/- 13%, NS), or presence of heart failure (New York Heart Association class III or IV in 12 of 59 vs 40 of 164, NS). The incidence of ventricular late potentials was 10% (6 of 59) in group A and 24% (39 of 164) in group B (p less than 0.05). Among the 146 patients who underwent coronary arteriography, the incidence of ventricular late potentials was 13% (10 of 80) in patients with a patent infarct-related artery and 26% (17 of 66) in patients with an occluded infarct-related artery (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
A typical aspect of motoneuron plasticity is the sprouting which occurs during muscle reinnervation, resulting in a transitory multiple innervation of the muscle cells. In order to verify the effect of a decreased protection from free radical attack on the sprouting, the multiple innervation in the extensor digitorum longus muscle, following sciatic nerve crush and regeneration, was studied in vitamin E-deficient rats. Thus, the innervated end-plates and the end-plates with multiple innervation were studied with histochemical and electrophysiological techniques. The percentage of innervated end-plates was similar in both groups at 30 as well as at 60 days after nerve crush. Nevertheless, multiple innervation was found in a larger part of the muscle and it lasted longer in the deficient rats. This finding is discussed in relation to some of the major hypotheses of sprouting; it may be relevant in the treatment of some lesions of peripheral nerve.
The reduction of the forceps major of the corpus callosum was estimated quantitatively in relation to the lesions to the neocortex in animals to which methylazoxymethanol-acetate (MAM) had been administered on the 13 th, 15 th or 17 th day of embryonic development. The specimens which received a prenatal injection of MAM the 13 th or 15 the day of gestation show noticeable reductions in both the extension of the occipital neocortex and the forceps major of the corpus callosum. Parallelly in MAM 13 there is a significant reduction in cell density both in the deeper layers and the more superficial ones, whereas in MAM 15 only the supragranular layers seem to be altered. Such a quantitative analysis shows a close correlation among the decreases in the area of the forceps major of the corpus callosum, in the area of the occipital neocortex and in cell density of the infragranular and supragranular layers.
The clinical usefulness of scintigraphies with 111Indium radiolabeled antimyosin antibodies (Myoscint) and 99mTc isonitriles (Cardiolite) for the detection and topographic location of acute myocardial infarction (AMI) has been evaluated in 29 patients admitted for suspected AMI. The scintigraphic results were compared to ECG and enzymatic data and, in 22 patients, to coronaro-angiography. The CK enzymes (from 258 to 4986 IU/l, mean 1429) were elevated in all, while the ECG showed diagnostic Q waves in only 21 patients. 2 patients died in cardiogenic shock, one after massive extension of AMI. Myoscint and Cardiolite images were positive in all 29 patients. Both techniques showed concordant results in 27/28 comparable patients, and localized the AMI in 8 patients without diagnostic ECG. Regional comparison in 140 segments of 28 patients was concordant in 91% of the segments, totally discordant in 3 segments and partially discordant in 9 segments. In conclusion, this preliminary study in selected patients shows the clinical usefulness of 111In radiolabeled antimyosin antibodies and 99mTc isonitriles for detection of AMI in all 29 patients and for topographic localization in more than 90% of the cases. Imaging with 111In radiolabeled antimyosin antibodies seems particularly useful in patients with non diagnostic ECG and previous MI and for the detection of right ventricular infarct extension.
Methylazoxymethanol acetate (MAM ac) injected prenatally affects development of neocortex in mice. Treatment at 13 days of gestation results in cortical hypoplasia that affects all the cortical layers except the first. Treatment at 15 days of gestation causes a statistically significant reduction in cell density in the superficial layers, while the deepest layers show no significant differences compared to the controls. Treatment at 17 days of gestation causes an alterated arrangement of the cortical layers, not easily separable since MAM ac in limiting perhaps glial cell proliferation, modifies the subsequent migration mechanisms. Fetal MAM exposure prevents proliferation of the various cortical laminae and there aren't subsequent compensatory phenomena.
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We investigated the fine morphology of basal cell in the frog's taste organ by means of transmission electron microscopy. Results show that basal cells are placed at the base of the disc and are highly polarized; the cell body is peripherally located and a long cell process reaches the central region of the taste disc without branching. The cell body contains the nucleus, the Golgi apparatus and large lysosomes; junctions between more peripherally located 'marginal' cells prevent passage of macromolecules from oral ambient to basal cells as shown by horse-radish peroxidase experiments. The cell process, running just over the basement membrane in the taste disc epithelium, is rich in microtubules, filaments and clustered secretory granules arranged near the plasmalemma. Nerves interrupting the basement membrane make synaptic-like junctions with basal cells. The cell process ends in the central region of the taste disc; here, the basal cell is expanded to contain filaments, secretory granules and mitochondria in characteristic arrangement and contacts intraepithelial nerve endings as well as basal processes of sensory and supporting cells. Marginated granules are found where basal cell contacts nerve ending and also where nerve and sensory cells contact basal cell. Our findings are consistent with the hypothesis that basal cells are under nerve control and that they may have a diffuse (paracrine) influence on neighbouring cells in the frog's taste organ.
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The peak filling rate (PFR) is an index of the diastolic function and has been proposed as an excellent parameter for the evaluation and early detection of left ventricular (LV) dysfunction. This study contributes to the assessment of LV diastolic function at rest and during submaximal exercise in 19 normal subjects and in 42 patients with coronary artery disease (CAD). The PFR was compared to the ejection fraction (EF) and the peak ejection rate (PER)--both indexes of systolic LV function--after acquiring a high-resolution time-activity curve (time/frame between 10 and 30 msec) with gated radionuclide angiocardiography. In 23 patients with normal EF at rest (greater than or equal to 50%), PFR and PER were abnormally low in 87% and 43% of the cases respectively. During submaximal exercise in 13 CAD patients, EF, PFR and PER varied very little from baseline values but were significantly reduced compared to the values of normal subjects. The PFR proved to be a very sensitive indicator of LV dysfunction in coronary patients but was not capable of discriminating between one-, two- or three-vessel disease. Our results tend to show the PFR to be a good indicator of LV dysfunction at rest and during exercise and its usefulness for the assessment of LV function is becoming more and more evident in clinical practice.