[Is the coronary artery disease in woman so different from the man]

Clinical presentation and symptoms of coronary artery disease may vary according to gender. This is not true to the same extent for acute coronary syndromes. The diagnosis is more complex in women because they show less often a typical clinical picture. In spite of these gender-related clinical differences, no diagnostic strategy in the detection of the coronary artery disease is recommended for women. Because "standard" treadmill or bicycle ECG stress test has a low specificity in women, non-invasive imaging (stress echocardiography, myocardial scintigraphy or cardiac magnetic resonance) should be preferred for the evaluation of myocardial ischemia in women.

[Do we have to be scared of chronic constitutional low blood pressure]

Chronic constitutional low blood pressure entity has been poorly studied. Typically, affects quality of life, because of manifold symptoms. Its mechanisms are not well understood but diminished cerebral blood flow, microcirculation and autonomic deregulation have been documented. Its' treatment is disappointing, without any demonstrated improvement of symptoms or prognosis. Thus, a complete medical examination is needed to exclude any organic cause. If none is found, it is important to reassure the patient and to convince him not to use expensive drugs potentially generative of side effects.

[Stress echocardiography: it is all in the contrast!]

The availability of myocardial contrast echocardiography has potential for several applications in coronary disease. Experimental studies have demonstrated a good correlation between measurements of myocardial blood flow and regional contrast intensity, and therefore capabilities of myocardial contrast echocardiography in detecting myocardial ischemia during stress. Recently, clinical studies have confirmed the value of this new technique in comparison with radionuclide imaging.

[Resistant hypertension]

Hypertension is a cardiovascular risk factor which needs a good evaluation before treatment. When this latter is decided, the target is to normalize high blood pressure. This requires a complete information of the patient; the latter will also receive individualized non pharmacological advices and also possibly different antihypertensive drugs. When blood pressure does not normalize, one must check the pressure measurement technique, the compliance to treatment and potential pharmacological interferences. Secondary hypertension is only considered if resistance to therapy cannot be found. It should be remembered that obesity and sleep apnea disorders are responsible of many instances of resistant hypertension.

[Silent myocardial ischaemia: a deafening silence]

Angina pectoris, whether stable or unstable, is not the most common ischaemic manifestation of coronary heart disease. Silent or asymptomatic ischaemia is the most frequently encountered ischaemic event in coronary heart disease. nevertheless, its prevalence is very variable, depending on the studied population (2-4% in asymptomatic patients, 20-30% after an myocardial infarction, 40-60% in stable angina and 60-80% in unstable angina). In this context, silent ischaemia raises many questions with regards to the rational use of diagnostic tools (stress test, holter electrocardiographic recording and stress imaging tests), their prognostic interpretation and its management.

Unusual presentation of a left ventricular aneurysm

We report on a case of left ventricular aneurysm in a 42-year-old woman presenting with atypical chest pains. The resting electrocardiogram showed abnormal Q and T negative waves in leads II, III, and aVF. Transthoracic echocardiography revealed an aneurysm on the posterior wall of the left ventricle. Thallium myocardial tomoscintigraphy confirmed the presence of a persistent defect with uneven uptake in the posterior wall, and coronary arteriography showed perfectly normal coronary arteries. A left ventricular aneurysm associated with normal coronary arteries and transient ischemia was diagnosed following a comparison with one of the patient's old electrocardiograms.

Alpha-tocopherol controls cell proliferation in the adult rat dentate gyrus

The effect of alpha-tocopherol on cell proliferation and proliferated cell survival was investigated in the dentate gyrus of adult rats. Adult rats were supplemented with alpha-tocopherol, injected with 5-bromo-2'-deoxyuridine (BrdU), that is incorporated into DNA during the S-phase, and killed at different time after BrdU injection. The number of newborn cells decreased after alpha-tocopherol supplementation, confirming the hypothesis that alpha-tocopherol is able to depress cell proliferation in vivo. Most newborn cells die within few days; more newborn cells survive in alpha-tocopherol-treated rats, suggesting the hypothesis that alpha-tocopherol decreases cell death.

Diagnosis of coronary artery disease in patients with permanent cardiac pacemaker by dobutamine stress echocardiography or exercise thallium-201 myocardial tomography

This study evaluated the use of dobutamine stress echocardiography and exercise thallium-201 myocardial computed tomography (CT) in the diagnosis of coronary artery disease (CAD) in patients with permanent transvenous pacemaker with the electrode implanted in the right ventricle (RV). Twenty-nine consecutive patients with pacemaker underwent dobutamine stress echocardiography, exercise thallium-201 myocardial CT, and coronary arteriography over a period of 8 +/- 1 days. None of these patients had suffered a myocardial infarction (MI). The cardiac rhythm of every patient was electrically paced during echocardiography and tomography. Sixteen (55%) patients showed CAD on angiography (stenosis > or = 50% of the luminal diameter of a major epicardial vessel). The detection sensitivity for CAD was 94% for the tomography and 88% for the echocardiography (P = NS). The difference between the sensitivities of the two techniques in detecting CAD based on the affected coronary artery was not statistically significant. Of the 13 patients without CAD, tomography showed a positive result in nine cases, i.e., a specificity of 31%, whereas echocardiography showed a positive result in only one case, i.e., a specificity of 92% (P < 0. 01). Exercise thallium-201 myocardial computed tomography produces an increased rate of false-positive results in patients with permanent transvenous cardiac pacemaker (PCP) implanted in the right ventricle (RV). Dobutamine stress echocardiography can thus be used to reduce considerably the level of false-positive results in these patients and still retain a detection sensitivity for CAD equal to that of myocardial tomography.

Spatial learning affects immature granule cell survival in adult rat dentate gyrus

Neurogenesis occurs throughout life in mammalian dentate gyrus. The effect of learning on newborn cell survival was studied in rat. Rats were trained on a hippocampus-dependent spatial learning task by using Morris water maze. Neurogenesis was evaluated by 5-bromo-2'deoxyuridine administered before learning. Several newborn cells expressed the immature neuron marker TOAD-64. The main findings were as follows: (1) the survival of newborn cells was enhanced by learning at early stage of differentiation; (2) the newborn cells saved by learning were mainly located in the rostral part of external blade of granule cell layer and (3) there was a correlation between the actual individual learning and newborn cell survival.

Clinical study to investigate the predictive parameters for the onset of atrial fibrillation in patients with essential hypertension

BACKGROUND

The risk factors involved in the onset of atrial fibrillation (AF) are well known, but the predictive clinical and paraclinical parameters for the onset of AF in hypertensive patients have not been investigated specifically.

METHODS AND RESULTS

We retrospectively analyzed 97 consecutive patients with hypertension and no known history of AF or cardiovascular events who attended the cardiology outpatient clinic. The analysis was based on clinical data, the noninvasive ambulatory 24-hour measurement of blood pressure (AMBP), a standard 12-lead electrocardiogram, and a Doppler echocardiogram. After a mean follow-up of 25 +/- 3 months, 19 (19. 5%) patients had AF, 3 (15.8%) of whom had a cerebrovascular accident. The patients with AF were older than the others and their AMBP showed higher mean systolic diurnal and nocturnal blood pressures, though no differences in the clinical blood pressure readings were present. On the electrocardiogram, the maximum duration of the P wave and its dispersion were more prolonged in the patients with AF. On the Doppler echocardiogram, left ventricular mass and left atrial dimension were higher in the patients with AF, and the A-wave velocity of diastolic mitral flow was reduced in these patients. In the multivariate analysis, age (odds ratio 3.28, P <.001), diurnal systolic blood pressure (odds ratio 1.35, P <.01) and nocturnal systolic blood pressure (odds ratio 1.16, P <.01), maximum duration of the P wave (odds ratio 2.09, P <.01), dispersion of the P wave (odds ratio 2.52, P <.001), echocardiographic left ventricular mass (odds ratio 1.43, P <.01), left atrial dimension (odds ratio 2.81, P <.001), and velocity of the A wave (odds ratio 2. 24, P <.01) were independent predictors for the onset of AF. After correction for age, maximum duration of the P wave (odds ratio 1.34, P <.01), dispersion of the P wave (odds ratio 1.63, P <.001), and the velocity of the A wave (odds ratio 1.42, P <.01) remained independent predictors for the onset of AF.

CONCLUSIONS

In patients with hypertension, age and the level of diurnal and nocturnal systolic blood pressures measured by 24-hour AMBP are important independent predictors for the onset of AF. Independent of age, increases in left atrial dimension and left ventricular mass, prolongation of the maximum duration and dispersion of the P wave and reduced A-wave velocity are also predictors for the onset of AF.

Are there proliferating neuronal precursors in adult rat dorsal root ganglia?

The origin of new neurons in dorsal root ganglia of adult rat was investigated using an experimental model in which postnatal neurogenesis naturally occurring is enhanced and restricted in a brief period of life. Possible mitotic origin of new neurons was investigated by means of 5-bromo-2-deoxyuridine, anti-NF 200 antibody was used to detect if proliferated cells showed a neuronal phenotype. The results suggest that postnatal neurogenesis in dorsal root ganglia could depend only in part on precursor proliferation and that normally new neurons derive from the late differentiation of postmitotic cells.

Postnatal proliferation of DRG non-neuronal cells in vitamin E-deficient rats

Changes in the number of satellite cells in neuron body sheaths in dorsal root ganglia (DRGs) were studied from 1 to 5 months of age in control and in vitamin E-deficient rats; furthermore, the satellite cell proliferation rate was detected in the same groups of animals with immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU). The number of satellite cells in sheaths of DRG neurons increased in the period of life considered both in control and in vitamin E-deficient rats. Satellite cell proliferation was observed in both groups, but its rate was found to be higher in vitamin E-deficient rats. The results obtained in control rats confirm that mitotic ability is retained by satellite cells in adulthood and show that at least some of newborn satellite cells add to the pre-existing population. The results obtained in vitamin E-deficient rats suggest that a faster turnover in satellite cell population takes place in these animals and support the idea that vitamin E could be an exogenous factor controlling cell proliferation.

Neurogenesis in the adult rat dentate gyrus is enhanced by vitamin E deficiency

Neurogenesis occurs throughout adult life in rat dentate gyrus. Factors and mechanisms of adult neurogenesis regulation are not well known. Vitamin E deficiency has been found to deliver a neurogenetic potential in rat dorsal root ganglia. To determine whether the role of tocopherols in adult neurogenesis may be generalized to the central nervous system, changes in adult rat dentate gyrus neurogenesis were investigated in vitamin E deficiency. Neurogenesis was quantitatively studied by determination of the density of 5-bromo-2'-deoxyuridine (BrdU)-labeled cells and by determination of the total number of cells in the granule cell layer. The BrdU-labeled cells were immunocytochemically characterized by demonstration of neuronal marker calbindin D28K. The following results were found: (1) the volume of the granule layer increased in controls from 1 to 5 months of age, mainly due to cell density decrease; (2) the volume increased by a similar amount in vitamin E-deficient rats, mainly because of an increase in cell number; (3) BrdU-positive cells were more numerous in vitamin E-deficient rats in comparison to age-matched controls; (4) the increase in proliferated cells was located in the hilus and in the plexiform layer. This study confirms that neurogenesis occurs within adult dentate gyrus and demonstrates that this process is enhanced in vitamin E deficiency. This finding indicates that vitamin E may be an exogenous factor regulating adult neurogenesis.

[Clinical value of measuring systolic arterial blood pressure post-exercise for evaluation and diagnosis of coronary disease: comparative study between women and men]

It has been demonstrated that the ratio of the systolic blood pressure post-exercise to that at peak exercise (rSBP) is a criterion for diagnosis and severity of coronary artery disease (CAD) in men. No such demonstration has been attempted in women. We have compared SBP to classical signs of ischemia, such as ST segment depression and angina pectoris, in a group of 788 ambulatory patients of whom 357 were women. All underwent a bicycle ergometric test and a coronary angiogram. The prevalence of CAD at angiography was the same for both genders (women 43.5% and men 47%) with no significant difference in the number of vessels diseased. In patients with CAD, the rSBP was significantly more elevated than in others, at 1 minute (p < 0.01) and even more so at 3 minutes (p < 0.001) post-exercise, with no gender difference. The most discriminating value of rSBP at 3 minutes post-exercise for diagnosis of CAD was situated at 0.91 for sensitivity and specificity (receiver operating characteristic curve analysis). In the whole group sensitivity of rSBP is lower, while the specificity is greater than classical criteria of ischemia. The sensitivity of rSBP is poor for the diagnosis of single vessel disease, but of equal value compared to ST segment depression in the presence of multivessel disease, with no gender difference. The specificity of rSBP is higher than ST segment depression in women (p < 0.001) compared to men (p < 0.05). rSBP has a positive correlation with the number of coronary vessels diseased but not with the extent of ST segment depression. Our study demonstrates that rSBP at 3 minutes post-exercise is a less good diagnostic sign than the classical criteria of myocardial ischemia. However, rSBP has good specificity, particularly in women, thus reducing false positive tests related to ST segment depression. rSBP is also a marker of the severity of coronary artery disease.

Neuron and glial cells in neocortex after methylazoxymethanol treatment in early development

The quantitative changes were investigated in neuron and glia density in the different cortical layers of the frontal cortex of 3 and 12 month old mice, exposed to methylazoxymethanol on embryonic day 13 (MAM13). No loss of cortical neurons was found between young and adult animals. MAM exposure on the 13th day of development induced a neuron density decrease throughout on the entire cortical depth and did not produce changes in the density of glial cells with respect to the controls and to age. Consequently, at 3 months of age we observe a glia/neuron ratio greater than that of controls and at 12 months a similar value. In the neocortex of MAM-mice at this numerical uniformity of glial cell density, did not correspond to a similar proportional composition: the frequency of the astrocytes is lower, adapting to the decreased neuron density; the greater oligodendrocyte percentage may be related to disturbed layering and to the hyperinnervation of the hypoplastic cortex; the microglia shows a trend similar to that of the controls. These results, together with those of other studies, suggest that prenatal exposure to MAM causes a cortical compensatory response regulating glial cells proliferation.

Vitamin E affects quantitative age changes in lumbar motoneurons and in their peripheral projections

Vitamin E deficiency was previously found to induce plastic changes in the number of primary sensory neurons and in motoneuron peripheral field projections. In this work, quantitative changes in motoneurons of lumbar segments, in nerve fibres constituting ventral roots and in innervating leg motor fibres were studied in normal and vitamin E deficient rats from 1 to 5 months of age. The number of lumbar motoneurons was found to decrease, while there were no changes in the number of ventral root fibres. An increase in the number of innervating leg motor fibres was observed during ageing in control rats; in vitamin E deficient rats the number of fibres in the ventral roots did not change, as occurred in controls, but the decrease in the number of motoneurons was smaller and the number of innervating leg motor fibres increased further in comparison to the controls. The findings are consistent with the idea that vitamin E deficiency causes a decrease in motoneuron death or, alternatively, that it induces some process partially compensating naturally occurring motoneuron death.

Motor nerve sprouting induction by a nerve explant in normal and vitamin E-deficient rats

Sprouting induction by a peripheral degenerating nerve has been evaluated in normal and vitamin E-deficient rats. A piece of sural nerve was grafted close to the peroneal nerve of the same animal: at one and two months after grafting thin unmyelinated axons were visible in the graft and they were sometimes functionally active; when nerve explant was frozen before grafting, sprouting induction did not take place either in controls or in vitamin E-deficient animals. No difference was noted in sprouting induction between the two groups, while degeneration showed a different time course. Some hypotheses of possible stimuli of sprouting induction are discussed.

Changes in the number of primary sensory neurons in normal and vitamin-E-deficient rats during aging

In the dorsal root ganglia (DRGs) of vitamin-E-deficient rats, we previously found an increase in the number of neurons during the first 5 months of life (Cecchini et al., 1993, 1994). This neurogenetic event seems to bring forward in time the increase in the number of primary sensory neurons that Devor et al. (1985) found in normal rats aged more than 1 year, but that other authors have not confirmed. The present study had two aims: first, to verify whether neurogenesis spontaneously occurs in DRGs of 14-month-old Sprague-Dawley rats; and, second, to determine whether the neurogenesis enhanced by vitamin E deficiency continues further in the long run, or whether it stops or reverses into neuron loss. A quantitative and morphometric analysis was performed on neurons of L3-L6 DRGs in 14-month-old normal and vitamin-E-deficient rats: the results obtained were compared to those previously obtained in 1-month-old and 5-month-old animals of both dietetic treatment groups, in order to observe the effects of aging on these neuronal populations. The total number of DRG neurons in the control group was higher in older than in younger animals, whereas the value in the vitamin-E-deficient group was lower in older than in younger animals. The present data confirm that neurogenesis occurs in DRGs of normal rats during adult life. Moreover, they show that once the premature neurogenesis in the deficient rats is completed, no further increase in the number of neurons takes place.

"Acquired" left ventricular-to-right atrial shunt (Gerbode defect) after bacterial endocarditis

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)

Regeneration of unmyelinated peripheral axons in vitamin E-deficient rats

Unmyelinated axons of normal and regenerated sciatic nerve were counted in controls and vitamin E-deficient rats. No significant change in the number of unmyelinated axons of uninjured nerve was found in the vitamin E deficiency in comparison to controls (12961 +/- 1591 and 12450 +/- 1290, respectively, mean +/- SEM). In regenerated nerve of control rats the number of unmyelinated axons was higher than in uninjured nerve (16971 +/- 1854 and 20786 +/- 1574 at 1 and 2 months after crush, respectively). In vitamin E-deficient rats the increase in number of unmyelinated axons was greater than in corresponding controls (21880 +/- 662) at 1 month after lesion, but the number returned to value found in uninjured nerve at 2 months after lesion (12536 +/- 659). These results suggest that sprouting at lesion may be enhanced but some regenerated axons does not survive at long term in vitamin E-deficiency.

Increased number of sciatic sensory neurons in vitamin-E-deficient rats

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.

Morphological analysis on the adrenal zona fasciculata of Ginseng, Ginsenoside Rb1 and Ginsenoside Rg1 treated mice

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.

Early exercise testing after acute myocardial infarction in the elderly: clinical evaluation and prognostic significance

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)

[Mid-term clinical and prognostic evaluation of idiopathic atrial fibrillation]

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.

Nodal and terminal sprouting by regenerating nerve in vitamin E-deficient rats

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.

Increased number of dorsal root ganglion neurons in vitamin-E-deficient rats

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.

[Changes due to age in the regenerating axons of the adult rat]

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.

Reduction in the frequency of ventricular late potentials after acute myocardial infarction by early thrombolytic therapy

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)

Evaluation of left ventricular diastolic function at rest and during exercise by gated radionuclide angiocardiography in coronary artery disease patients

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.

Time course of sprouting during muscle reinnervation in vitamin E-deficient rats

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.

Effect of vitamin E-deficiency on regeneration of the sciatic nerve

The regeneration of the sciatic nerve fibres was studied in both normal and vitamin E-deficient rats at 30 and 60 days after crush. The vitamin E is involved in one of the most important mechanisms of protection against peroxidation of plasma membrane lipids; the plasma membrane plays certainly a role in nerve regeneration. Both the diameter and the total number of myelinated nerve fibres was calculated at different times. The number of myelinated fibres in the undenervated deficient animals was lower than that found in the undenervated normals animals. Following the nerve crush, in normal animals after two months the number of myelinated fibres exceeded the number found in undenervated normal animals, whereas in the deficient rat nerves it was significantly lower than in the corresponding controls and moreover it did not even reach the number found in the nerves of undenervated deficient rats. Finally, the caliber distribution of myelinated fibres in undenervated and denervated deficient rats shows a relative percent increase in the number of greatest axons and a decrease in smaller axons. This result confirm the vitamin E to be an important factor of the normal process of nerve regeneration.

[Diagnosis of acute myocardial infarct using 2 new tracers: 111indium-labeled antimyosin antibodies and 99m-technetium isonitriles]

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.

The fine morphology of the basal cell in the frog's taste organ

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.