P125 CORONARY REVASCULARIZATION GUIDED BY STRESS ECHOCARDIOGRAPHY WITH ULTRASOUND CONTRAST: A CASE

Echocontrastography is an echocardiography method that involves the intravenous administration of a particular contrast medium, formed by microbubbles capable of crossing the pulmonary circulation and distributing themselves in the left sections. These micro bubbles hit by ultrasound break or oscillate emitting ultrasound waves with a different frequency than the beam that hit them, generating a series of harmonic signals that can be processed to observe, for example, the opacification of the left cavities. An 82–year–old diabetic hypertensive man with a strong family history of coronary artery disease underwent routine cardiac evaluation. At the time of the visit, sporadic episodes of non–specific chest pain (localized in the right breast), of an intermittent nature, and not related to physical exertion, were reported. On the ECG, finding of sinus rhythm and q waves in V1–V3 (not present at a previous in 2019). On echocardiography (patient with poor acoustic window): Left ventricle of normal size with mild concentric parietal hypertrophy. Slight reduction in global systolic function due to alterations in district kinetics. Akinesia of the apex and middle segment of the septum and anterior wall. FE 48%. Doubtful apical iso–hyperechoicity (artifact?). Urgent hospitalization for coronary angiography was indicated in the suspicion of subacute anterior AMI. Coronary angiography revealed occlusion of anterior interventricular artery (IVA) in the proximal tract, partially re–inhabited downstream by homocoronary circulation (figure 1). Before proceeding with revascularization, given the absence of movement of the myocardiocitonecrosis indices, it was decided to perform myocardial viability tests. In consideration of the suspected apical thrombotic formation, as well as the patient‘s poor acoustic window, echo contrast was necessary (Figure 2). Once the complete opacification of the left ventricular cavity was highlighted by the contrast agent, suggestive of the absence of apex thrombi, we proceeded to ecostress with dobutamine to evaluate myocardial viability. At the explored dosages (5 – 10 and 20 ug/kg/ min) recovery of the apex kinetics was observed, but not of the mid–apical septum, which remained akinetic. We then proceeded to angioplasty on proximal IVA with a good angiographic result and the patient was discharged on the third day from revascularization in excellent clinical conditions.

P406 UNMASKING A PATTERN OF BRUGADA: FLECAINIDE VS AJMALINA

Brugada syndrome mainly affects men in the third and fourth decade of life. It presents with a typical electrocardiographic pattern, unmasked by sodium channel blocking drugs or hyperpyrexia. A 36–year–old young man, with no reported cardiovascular risk factors or family history of sudden death, had convulsions and loss of consciousness during hyperpyrexia, for which family members alerted the local emergency service. During transport to the hospital, the vital parameters and heart rhythm were normal, but, due to the onset of seizures, the patient was sedated, intubated and hospitalized in intensive care unit (ICU). The ECG performed at the entrance (in the course of hyperpyrexia) showed a dubious type 1 Brugada pattern (Figure 1). The echocardiogram (as well as the subsequent cardiac resonance) showed the absence of cardiac structural alterations. Prompt treatment of hyperpyrexia was recommended, the use of drugs listed on brugadadrugs.org was contraindicated and careful ECG monitoring was recommended. Non–sustained ventricular tachycardia was documented during the hospitalization in ICU. When the clinical picture stabilized with resumption of spontaneous breathing, the patient was transferred to our ICU for continuation of the diagnostic and therapeutic process (Figure 2). From the interview with the patient, a previous paroxysmal tachycardia from atrio–ventricular reentry emerged in antiarrhythmic prophylaxis for several years with Propafenone and subsequently treated with catheter ablation of the right lateral accessory path. Considering the lack of documentation of complex ventricular arrhythmias by the 118 during transport to the hospital and during the stay in the UTIC, the long antiarrhythmic therapy with sodium channel inhibitors, as well as the absence of a typical Brugada pattern during fever, we decide to perform a Flecainide test (2 mg / Kg in 10 ‘), negative result for Brugada type 1 pattern (Figure 2) In the following days, considering the absolute negativity of all the neuroradiological and EEG investigations, not having found the cause of the loss of consciousness during hyperpyrexia, we performed ajmaline test (1 mg / kg in 100 cc of SG5% in 10 ‘) with the identification of the diagnostic pattern type 1 (Figure 3). Finally, the implantation of a subcutaneous cardioverting defibrillator (S–ICD) was performed.

P176 MITRAL FISTULA IN PATIENT WITH OUTCOMES OF TRANSCATHETER AORTIC VALVE IMPLANTATION: A CASE REPORT

Infective endocarditis (IE) following transcatheter aortic valve replacement (TAVR) has been associated with a poor prognosis. The development of an aorto–atrial fistula (AAF) is a rare but problematic complication of IE, which can be confirmed with transesophageal echocardiography. A 55–year–old man, asthmatic and allergic (Penicillin and ASA) went to the emergency room for therapy–resistant hyperpyrexia and was admitted to Medicine Department for the necessary investigations and treatment. In remote pathological history: ischemic heart disease with dilated–hypokinetic evolution, already revascularized by CABG in 1996 and by PTCA in 2006 and in 2016; transcatheter aortic valve replacement with biological prosthesis in 2018. In the next medical history: admission to neurosurgery about 9 months before for cerebral haemorrhage and implantation of CRT– ICD about 6 months before On the echocardiogram performed at the entrance, evidence of isoechoic formation on the mitral flap for which further study with TEE was recommended. Blood cultures performed during hospitalization were positive for S. Epidermidis Oxacillin resistant. Few days after the admission, due to a sudden worsening of the respiratory picture, the patient was subjected to oro–tracheal intubation and transferred to Intensive Care Unit. The transesophageal echocardiogram (figure) performed in urgency documented: “fistula on the anterior flap of the mitral with medium–severe flow directed from the outflow tract of the left ventricle to the posterolateral wall of the left atrium.” On the recommendation of the infectious disease consultant, intravenous antibiotic therapy with Vancomycin and Gentamicin was started. In the following days, there was a progressive improvement in hemodynamics and the respiratory picture, for which the patient was transferred to Cardiac Surgery to undergo mitral valve replacement surgery. In literature, patients with perivalvular extension of infective endocarditis show very high early and late mortality rates, and surgery during hospitalization for IE appeared to be associated with better outcomes.

Performance evaluation of the automated nucleated red blood cell count of five commercial hematological analyzers

INTRODUCTION

Recent automated hematology analyzers (HAs) can identify and report nucleated red blood cells (NRBC) count as a separate population out of white blood cells (WBC). The aim of this study was to investigate the analytical performances of NRBC enumeration on five top of the range HAs.

METHODS

We evaluated the within-run and between-day precision, limit of blank (LoB), limit of detection (LoD), and limit of quantitation (LoQ) of XE-2100 and XN-module (Sysmex), ADVIA 2120i (Siemens), BC-6800 (Mindray), and UniCel DxH 800 (Beckman Coulter). Automated NRBC counts were also compared with optical microscopy (OM).

RESULTS

The limits of detection for NRBC of the BC-6800, XN-module, XE-2100, UniCel DxH 800, and ADVIA 2120i are 0.035×10⁹ /L, 0.019×10⁹ /L, 0.067×10⁹ /L, 0.038×10⁹ /L, and 0.167×10⁹ /L, respectively. Our data indicated excellent performance in terms of precision. The agreement with OM was excellent for BC-6800, XN-module, and XE-2100 (Bias 0.023, 0.019, and 0.033×10⁹ /L, respectively). ADVIA 2120i displayed a significant constant error and UniCel DxH 800 both proportional and small constant error.

CONCLUSION

Regards to NRBC counting, the performances shown by BC-6800, XN-module, and XE-2100 are excellent also a low count, ADVIA 2120i and UniCel DxH 800 need to be improved.

Effects of aging and cyclosporin a on collagen turnover in human gingiva

Background:

We aimed at characterizing the aging gingiva analyzing: i) collagen content and turnover in human gingival tissues and fibroblasts obtained from healthy young and aging subjects. ii) the effect of cyclosporin A administration in human cultured gingival fibroblasts obtained from aging compared to young subjects.

Methods:

Morphological analysis was performed on haematoxylin-eosin and Sirius red stained paraffin-embedded gingival biopsies from young and aging healthy subjects. The expression of the main genes and proteins involved in collagen turnover were determined by real time PCR, dot blot and SDS-zymography on cultured young and aging gingival fibroblasts, and after cyclosporin A administration.

Results:

Our results suggest that in healthy aged people, gingival connective tissue is characterized by a similar collagen content and turnover. Collagen turnover pathways are similarly affected by cyclosporin A treatment in young and aging gingival fibroblasts.

Conclusions:

Cyclosporin A administration affects gingival collagen turnover pathways in young and aging fibroblasts at the same extent, suggesting that during aging cyclosporin A administration is not related to relevant collagen turnover modifications.

Reticulocytes in untreated obstructive sleep apnoea

BACKGROUND AND AIM

The short, repetitive hypoxaemic episodes observed in obstructive sleep apnoea (OSA) may determine small augmentations in mature red blood cells. It is unknown whether they affect reticulocyte release. This study explored whether the number and degree of maturation of circulating reticulocytes may be altered in OSA, possibly through the effect of erythropoietin.

METHODS

Fifty male adult patients with suspected OSA, normoxic during wakefulness, were studied. After nocturnal polysomnography, a blood sample was withdrawn for blood cells count, erythropoietin, iron and transferrin determination. Reticulocyte concentration and degree of immaturity [high (H), medium (M), or low (L)] were also determined. Immature reticulocyte fraction (IRF) was calculated as (M+H) percentage of reticulocytes.

RESULTS

A wide range of OSA severity was found [apnoea/hypopnoea index (AHI): 44.3 +/- 30.4, range 0.3-105; sleep time spent at oxyhaemoglobin saturation <90%: 18.1 +/- 22.2%, range 0-81%]. Both reticulocyte count and IRF slightly exceeded the normal range. Patients with a reticulocyte concentration > 2% had higher EPO levels (p < 0.05), but not worse nocturnal desaturations, than those with values < 2%. By contrast, subjects with IRF < 15% showed worse desaturations (p < 0.05), but similar EPO concentrations, when compared to subjects whose IRF was < 10%. At univariate analysis, reticulocyte count correlated to erythropoietin, while IRF to transferrin saturation, BMI and OSA severity. At multiple regression, only lowest nocturnal oxygen saturation remained a significant contributor to IRF (r2 0.223, p < 0.05).

CONCLUSIONS

This data suggests that hypoxaemia due to OSA could influence the release of immature reticulocytes, but this effect is not mediated by erythropoietin.

Extracellular glycosaminoglycan changes in healthy and overgrown gingiva fibroblasts after cyclosporin A and cytokine treatments

BACKGROUND

It has been demonstrated that cyclosporin A (CyA) blocks the immune system, acts on cytoskeleton and stimulates the production of extracellular matrix (ECM) and transforming growth factor-beta1 (TGF-beta1). This cytokine, such as transforming growth factor-alpha (TGF-alpha), induces deposition of glycosaminoglycans (GAG), proteoglycans and collagen fibres in the ECM.

METHODS

In this work, we examined the effect induced by CyA, TGF-beta1 and TGF-alpha on cultures of healthy and overgrown human gingival fibroblasts in order to evaluate the glycosaminoglycan, cytoskeletal changes and the behaviour of fibroblasts after concanavalin A (Con A) treatment. Moreover, we examined gingival biopsies by Alcian blue histochemical staining and electron transmission microscopy.

RESULTS

Total and extracellular sulphated GAG in overgrown gingiva specimens and in derived fibroblast cultures treated with CyA and cytokines were significantly higher than controls. The action of cytokines was increased (P < or = 0.01) compared with CyA with a greater effect of TGF-alpha in comparison with TGF-beta1; the electron microscopy showed ECM accumulation. The agglutinations showed the heterogeneity of fibroblast populations.

CONCLUSIONS

Stimulation with Con A showed that the fibroblast population had cell surface heterogeneity, and could respond in a different way to both CyA and cytokine stimulus. Moreover, increased synthesis of GAG in overgrown gingiva compared with synthesis in normal fibroblasts before CyA treatment suggests a possible genetic origin of damage. As not all CyA-treated patients develop gingival overgrowth, a genetic predisposition may explain the different responses of gingival fibroblast populations.

Polyamine levels and ornithine decarboxylase activity in blood and erythrocytes in human diseases

Serum and erythrocyte levels of the polyamines spermine, spermidine and putrescine, as well as ornithine decarboxylase in erythrocytes, were studied in patients with different neoplasms (breast, lung and colon cancer) and in those with a nonmalignant proliferative disease (familial polyposis). The blood levels of polyamines and the spermine/putrescine ratio were significantly higher in all tumors and in nonmalignant colon polyposis. In erythrocyte ornithine decarboxylase activity, spermine and spermidine levels, as well as spermidine/putrescine and spermine/putrescine ratios showed a significant decrease after surgery and chemotherapy. Our data suggest that high levels of blood polyamines and erythrocyte ornithine decarboxylase activity are related to cell proliferation and cancer treatment, but that levels of polyamines in serum and erythrocytes are still significantly high after cancer treatment and are similar to those in polyposis disease. Polyamines are related to nuclear activity during differentiation; therefore, the altered turnover of polyamines could be a sign of abnormal nuclear function. Since polyamines stimulate protooncogene expression, their high levels could be considered an important cofactor in malignant cell transformation.

Extracellular signal-regulated kinases 1 and 2 phosphorylated neurons in the tele- and diencephalon of rat after visceral pain stimulation: an immunocytochemical study

We aimed at verifying whether extracellular signal-regulated kinases (erks) 1 and 2 are activated, i.e. phosphorylated, in forebrain neurons after visceral pain stimulation (VPS). Ether and urethane anaesthetized rats received an intraperitoneal injection of acetic acid or were left untreated (ECT, UCT). After 2 h the animals were perfused. Paraffin embedded brain sections immunoreacted with an antibody selective for the phosphorylated erks. The light microscope analysis revealed only a few labelled neurons in ECT, while in UCT, positive cells were detected. In VPS rats (VPSR) positive cells were mainly distributed in regions, such as the hypothalamic anterior and thalamic paraventricular midline nuclei, amygdala, hippocampal and parahippocampal, insular and perirhinal cortex, involved in nociception and/or visceral activities. Our data suggest an association of erks activation with the emotional component of nociception; moreover, they show that erks activation is not suppressed by anaesthesia.

A comparision between rapid Golgi and Golgi-Cox impregnation methods for 3-D reconstruction of neurons at the confocal scanning laser microscope

We utilized two widely used impregnation methods, the silver "rapid Golgi" and the mercuric Golgi-Cox methods, for three-dimensional (3-D) reconstruction of neurons at the confocal scanning laser microscope (CSLM), to determine which of them was more suitable for this application. The Golgi-Cox method is the most consistent arid the cleanest procedure with respect to the "rapid Golgi" one which always produces samples with scattered reflective granules that interfere with the image formation at the CSLM. The interneuronal tissue in the case of Golgi-Cox impregnated specimens (i.e. the non-impregnated tissue among impregnated neurons) contributes less to the decrease of reflected light during z-sectioning than in the case of "rapid Golgi" impregnation, but the mercury impregnated samples reflect less than the silver impregnated ones. Owing to the necessity during deep z-scanning to adjust the sensitivity of the CLSM detector the acquisition of images from the deeper planes of the sample may be difficult. In our opinion the "sandwich" mounting of the specimen between two coverslips is indispensable in order to make it possible to scan it from both sides and, thus reduce the penetration in the sample and the consequent distortion of the image. Neither of the impregnation methods used is completely suitable for CLSM observations due both to their intrinsic limitations and to those imposed by the sample thickness.

The cytoarchitecture of the adult human parabrachial nucleus: a Nissl and Golgi study

The parabrachial nucleus (PBN) plays important roles in numerous autonomic functions and in pain modulation. In different animal species, three main regions of the PBN have been identified: the m-PB, the l-PB, and the Kolliker-Fuse nucleus (KF). The KF has not been identified in humans. The present study used Nissl and Golgi-Cox material and morphoquantitative methods to investigate the cytoarchitectural organization of the adult human PBN, paying particular attention to neuronal features endowed with functional significance, i. e. the arborization of the neurons. The PBN neuron population is made up of elements which are heterogeneous in size, shape and dendritic arborization, and grouped into two regions, the lateral and medial PBN (l- and m-PB). It has been suggested that some large sized neurons located in the ventral region of the m-PB might be the counterpart of the KF. In the m-PB the fusiform neurons are the most numerous cells; in the l-PB the multipolar neurons prevail, and are particularly numerous in the dorsal l-PB. Since the dendritic arborization is generally the main target of afferent projections to a neuron, it is possible that the l-PB, and in particular its dorsal region, might be the main site for the endings of afferences to the human PBN.

Expression of Fos immunoreactivity in the rat supraspinal regions following noxious visceral stimulation

We used immunohistochemical detection of the Fos protein to study the neuronal activation in the brain of methoxyfluorane-anesthetized rats after noxious deep somatic or visceral stimulation. The anesthesia was effective in triggering gene induction in many brain regions. Nevertheless, Fos appeared de novo in several brain nuclei following noxious stimulation in anesthetized animals. This could be of clinical relevance, as it suggests that the gas anesthetic does not suppress noxious stimulus-evoked reactivity in brain neurons. Two types of visceronociceptive stimuli were used to compare the effects of a diffuse visceral inflammation (peritoneal inflammation) with those of a more restricted inflammation (urinary bladder inflammation). In the same supraspinal areas, there were very few immunostained neurons in unstimulated controls, whereas Fos-positive cells were slightly more numerous in anesthetized controls and significantly more numerous after noxious stimulation. The peritoneal inflammation induced more Fos-labeled neurons than the restricted visceral stimulation. Labeled cells were found in these cases mainly in the ventrolateral medulla, parabrachial complex, dorsal raphe nucleus, periaqueductal gray, several hypothalamic and thalamic nuclei, amygdaloid complex, and cortex. Altogether these findings indicated that somatic and visceral inputs generally activate the same neuronal groups. However, a separation between the activation of somatic and visceral pathways was found in some brain nuclei, such as the parabrachial complex, hypothalamic, and thalamic nuclei.

Supraspinal connections and termination patterns of the parabrachial complex determined by the biocytin anterograde tract-tracing technique in the rat

We have re-evaluated, using the anterograde tracer biocytin, supraspinal efferent projections from the parabrachial complex (PBN) to gain new information about the nature of its connections and nerve terminal patterns. We selectively injected biocytin into the 3 main regions of the nucleus (lateral PBN, medial PBN and Kölliker-Fuse nucleus). We observed distinct groups of ascending and descending fibres of different calibre from the PBN running throughout the brain and reaching many brain areas involved in the regulation of autonomic function. Here we detected labelled bouton-like terminals and fibres with en-passage varicosities. The ascending efferents from the lateral PBN mainly reached the reticular, raphe and thalamic nuclei, the zona incerta (ZI), central nucleus of the amygdala (CeA) and lateral area of the periaqueductal grey (PAG). Thin descending efferents reached the ventral region of the solitary tract nucleus (STN). The ascending efferents from the medial PBN were seen in the raphe nuclei, reticular nuclei, ventral and lateral areas of the PAG, thalamic nuclei, and in the medial and lateral nuclei of the amygdala. Descending efferents were seen in the STN and in some reticular nuclei. The ascending projections from the Kölliker-Fuse targeted the ventral area of PAG, CeA, ZI, lateral hypothalamic area, ventromedial thalamic nucleus and, with only a few terminals, the ipsi and contralateral reticular area. A large number of descending efferents reached STN, caudal and paragigantocellular reticular nuclei. The higher sensitivity of biocytin compared with other types of markers allowed us to determine more effectively the distribution, nature and extent of the supraspinal PBN connections. This suggested that in several nerve circuits the PBN probably plays a more important role than previously thought.

Dendritic arborization and spines of the neurons of the cat and human periaqueductal gray: a light, confocal laser scanning, and electron microscope study

Neurons of the periaqueductal gray (PAG) have an extensive dendritic tree which plays an important role in the neuronal circuits supporting the functional activities of this region. The complexity of the local circuits is increased by the occurrence of dendritic spines. We have compared the dendritic and spine organization in the cat with that of man in order to verify whether an inverse relationship exists between dendritic tree extension and spine density and complexity. Sections of cat and human PAG prepared according to the Golgi-Cox method were studied with the conventional light microscope (LM) and the confocal laser scanning microscope (CLSM). The cat PAG was also studied at the electron microscopic level. The light microscopic study provided the morphoquantitative characteristics of the dendritic arborization and spines of the multipolar and fusiform neurons of the human and cat PAG. The CLSM methodology, thanks to the three-dimensional reconstruction of the neurons and the rotation of the reconstructed images, brought into view dendritic branches and spines that could not have been observed at the LM, thereby showing a wider dendritic tree and more numerous spines. The data combined from LM and CLSM demonstrate that in both species most spiny neurons are multipolar and probably projection neurons. In man, the multipolar neurons show a more extensive dendritic tree due to a wider secondary ramification, which would seem to be balanced by more numerous spines in cat. At the electron microscopic level, axo-dendritic synapses are numerous and show symmetrical and asymmetrical junctions in equal proportions; furthermore, the great majority of the spines are in contact with synaptic boutons which contain round vesicles and make predominantly asymmetrical contacts features which indicate excitatory activity. The combined use of different techniques gave a complete picture of the dendritic tree and spines of the neurons of human and cat PAG and showed a wider dendritic surface available for the receipt of the synaptic contacts than had been reported previously. Furthermore, our findings demonstrate that the PAG dendritic spines are important and specific structures in the synaptic complex of the neuropil, suggesting that they might create a local device to modulate and integrate the afferent inputs, probably in an excitatory way. The differences observed in the two species suggest that afferent information might be handled in different ways in human and cat PAG.

Cytoarchitecture of the abducens nucleus of man: a Nissl and Golgi study

The abducens nucleus is a pontine nucleus directly involved in oculomotion through its connections with the lateral rectus muscle of the eye. The aim of the present study was to investigate the cytoarchitectural organization of the abducens nucleus in man. The data obtained showed that the nerve cell bodies were small, medium and large in size and polygonal, oval, round or spindle shaped. The cytoplasm of all neurons appeared basophilic due to clearly evident scattered Nissl granules. On the basis of the characteristics of the dendritic arborization, multipolar and fusiform cells were identified. The multipolar neurons showed four to eight primary dendrites which gave off a wide secondary ramification. The fusiform neurons showed two dendrites emerging from the opposite poles of the elongated nerve cell body. The dendrites of all the neurons were largely confined within the boundaries of the nucleus. This finding would suggest that the neuronal relationships of the abducens nucleus supplied by the afferent fibers which pass through or end within it take place almost completely inside the nucleus. The wider dendritic arborization shown by the multipolar cells would indicate the latter as the principal target fields for the afferent inputs.

Fine structure of the interstitial nucleus of Cajal of the cat

The interstitial nucleus of Cajal (INC) is a mesencephalic nucleus considered to be an important premotor centre for eliciting vertical and rotatory eye and head movements. An ultrastructural analysis was carried out on the cat INC to elucidate the structure of the neurons and neuropil and, in particular, to examine the organisation of the synaptic relationships. The neuronal population is formed by a substratum of small and medium-sized neurons and by a limited number of larger neurons scattered throughout the nucleus. The small and medium-sized neurons display ultrastructural features similar to those shown by the cells of the central reticular formation. The larger neurons differ from those of the rest of the INC both in dimensions of their somata and in certain cytological characteristics (e.g. a well developed rough endoplasmic reticulum). Synaptic boutons are scarce at the level of the nerve somata and very abundant in the neuropil, thus indicating the latter as the main target field for the afferent inputs to the INC. Again the larger neurons are exceptions as their cell surface is extensively invested with axon endings. It is suggested that the larger neurons should be considered as a distinct cell population within the nucleus. On the basis of a morphometric analysis carried out on the synapses it is possible that in the INC, at the level of the somatic synapses, a mainly inhibitory role may be exerted, whereas in the neuropil it is possible that there is also excitatory control and modulation.

Enkephalin in the caudal PAG of rat: an immunocytochemical electron microscopic study

Enkephalins are opioid peptides which elicit an analgesic effect when injected into the periaqueductal gray matter and in particular into its caudal part. In this study we wanted to investigate the fine structure of the neurons and of the synaptic circuits involved in the enkephalin action in rats using immunocytochemical pre-embedding methods. The labelled neurons show a small-medium sized soma, with a large nucleus, an absence of an extensive granular endoplasmic reticulum and few synaptic contacts. The synapses on enkephalin dendrites are often multiple, unlabelled and show both symmetrical and asymmetrical junctions. Enkephalin axon terminals make synaptic contacts on dendrites, usually unlabelled; contacts between enkephalin elements were occasionally seen. The enkephalin synapses show a symmetrical type of junction. These data give morphological support to the physiological findings, in particular to those suggesting an inhibitory effect of enkephalin on periaqueductal gray matter cells through a post-synaptic process. The findings are discussed with respect to pain modulation taking into consideration the enkephalin synaptic complex in intrinsic circuits and the possible ending of enkephalin axons on the projective neurons of the periaqueductal gray matter.

A cluster analysis of the neurons of the rat interpeduncular nucleus

The morphometric characteristics of the neurons of the interpeduncular nucleus (IPN) in the rat were investigated by cluster analysis in order to identify neuronal groups which are morphometrically homogeneous, and to define their position and density in the IPN subnuclei. Two clusters of cells were detected. Cluster 1 neurons had a larger perikaryal size with a mean cross-sectional area of 170 microns2 and a high nuclear/cytoplasmic ratio. They were located mainly in the pars dorsalis (37%) and pars medialis (34%) rather than in the pars lateralis (29%). Cluster 1 neurons were also more frequent at the rostral (31%) and caudal (57%) poles than in the central part of the IPN. Cluster 2 cells showed a smaller mean perikaryal area (110 microns2), a small nucleus and abundant cytoplasm. They were equally distributed throughout the whole IPN. These findings suggest the existence of a magnocellular region at the rostral pole of the IPN which has not been described previously. The presence of IPN regions endowed with specific cytoarchitectural characteristics is discussed with respect to the complex neurochemical organisation of the nucleus.

The ultrastructural organization of the nucleus of the posterior commissure of rat

An electron microscope study was carried out to clarify the ultrastructure of the nucleus of the posterior commissure (NPC) of rat which is thought to be related to the eye movements and oculomotor reflexes. The neurons were small or medium-sized, loosely arranged in an extensive neuropil. The nerve cell bodies showed a high nucleocytoplasmatic ratio, scanty endoplasmic reticulum and very few axo-somatic contacts. The synaptic boutons were very numerous in the neuropil, thus indicating the latter as the main target for inputs to the NPC. The majority of the synapses showed the typical morphological features of the excitatory synapses and so it was hypothesized that a mainly excitatory activity takes place in the NPC. Since the NPC, together with the nucleus of Darkschewitsch (ND) and the interstitial nucleus of Cajal (INC) belongs to the accessory oculomotor nuclei, a comparison of their ultrastructure was carried out.

Intrinsic organization of the paramedian pontine reticular formation of the cat

A morphoquantitative analysis was carried out to clarify the cytoarchitectural organization of the paramedian pontine reticular formation (PPRF) which is considered to be an important site in the control of eye movements. The study was carried out on the cat, using the Golgi staining method. The topographic position and detailed structure of the neurons were demonstrated using morphoquantitative methods. On the basis of their neuronal arborization, fusiform neurons and two types of multipolar cells were identified. Fusiform neurons show dendrites which are given off from the two poles of the small- to medium-sized cell body. The arborization generally runs caudorostrally, ending inside the PPRF. These neurons are ubiquitous. Type 1 multipolar neurons, the most frequent elements of the neuronal population (60%), have a small- to large-sized cell body from which 2 or 3 primary spiny dendrites and the axon emerge. Their dendritic field is oval and generally oriented in the vertical plane. These neurons are scattered everywhere in the PPRF. Type 2 multipolar cells are large neurons endowed with numerous primary spiny dendrites constituting a wide round dendritic field and with a thick axon. They are located almost exclusively at the boundaries of the PPRF and preferentially in the caudal region. The characteristics of the neurons suggest that the fusiform cells may play an interneuronal role, while the multipolar neurons could have both a projective function and an important receptive role for the afferent fibers to the PPRF. The lack of homogeneity found among the multipolar neurons is in agreement with the variety of projective elements shown by functional investigations.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructure of substance P immunoreactive elements in the periaqueductal gray matter of the rat

Substance P (SP) is a non-opioid peptide that generates a potent analgesia when injected into the periaqueductal gray matter (PAG). The aim of this study was to investigate the fine neuronal structures and synaptic circuits involved in SP action in rats by means of electron microscopy, using immunocytochemical (ICC) pre-embedding methods. A conventional ultrastructural study, carried out to interpret the ICC data correctly, shows small sized nerve cell bodies with a high nucleus-cytoplasmic ratio; absence of an extensive granular endoplasmic reticulum; and few axo-somatic contacts having symmetrical and asymmetrical junctions in equal proportions. The large neuropil is characterized by numerous thin unmyelinated axons and axo-dendritic synapses mainly showing pleomorphic vesicles and asymmetrical junctions. The ICC analysis showed moderately labeled nerve cell bodies with the same structural, synaptic, and dimensional features as the negative cells. In the neuropil SP immunoreactivity is shown by dendrites, synapses, and thin elements which are unidentifiable structurally. No SP terminals synapsing on SP nerve cell bodies were found and only occasional SP light labeled terminals synapsing on negative perikarya were seen. The SP boutons generally have pleomorphic vesicles and asymmetrical junctions. On the basis of these data a possible excitatory activity of PAG SP synapses could be hypothesized. This activity would take place on postsynaptic neurons generally at a dendritic level. Our ultrastructural findings give support to an excitatory role carried out by SP neurons of the PAG, as suggested by the role of PAG circuitry on spinal nociception.

The cytoarchitecture of the nucleus cuneiformis. A Nissl and Golgi study

This investigation attempts to clarify the cytoarchitectural organisation of the neurons of the nucleus cuneiformis, a reticular nucleus of the midbrain particularly involved in locomotor activities. The study was carried out on the cat and man, in Nissl and Golgi material. The nerve cell bodies, which are small or medium sized, have a light basophilic cytoplasm and a large light nucleus usually containing one nucleolus. In Golgi material multipolar and fusiform cells can be identified. Multipolar cells, which form the majority of the neural population, have 3-7 primary spiny dendrites and an axon which often projects outside the nucleus. Fusiform cells have one or two primary dendrites endowed with spines, which are, however, less numerous than those of multipolar neurons. The axons generally end inside the nucleus. The main difference between man and the cat seems to be in the length and width of the neuronal arborisation, which are considerably greater in the former species. The characteristics of the two neuronal types suggest a projective function of the multipolar elements, but an interneuronal activity of the fusiform ones. The data support the similarity already found at the ultrastructural level between the nucleus cuneiformis and the periaqueductal grey matter, but on the other hand confirm the lesser degree of cytoarchitectural complexity of the nucleus.

The nucleus of Darkschewitsch in the cat: a Nissl, Golgi, and electron microscope analysis

A light and electron microscope study was carried out to elucidate the cytoarchitectural organization of the nucleus of Darkschewitsch (ND) in the cat. From the anatomical staining methods, including Nissl and Golgi-Cox, it appears that the ND shows a clear heterogeneity of shape and size of the neuronal population. The small or medium-sized neurons show a high nuclear/cytoplasmic ratio and a modest basophilia. Spiny extrusions are present on many of the neurons, arranged either as varicosities giving a rosary feature or clumped in small groups over the dendritic processes; these are absent at the level of the soma. From the electron microscope analysis it appears that the neuropil is not very extensive because the neuronal bodies are numerous and compact. The synaptic complex is extensive both at the level of the nerve cell bodies and at the level of the neuropil. Since many of the synapses display the features typical of the inhibitory synapses, it is possible that they represent the anatomical basis of an inhibitory integrative function.

A quantitative electron microscope study of the perikaryal projections of sensory ganglion neurons. II. Gecko and lizard

The perikaryal projections of the neurons in the thoracic spinal ganglia of gecko and lizard usually appear as finger-shaped evaginations running roughly parallel to the surface of the nerve cell body; they show a nearly circular cross section with a rather uniform transverse diameter having an average value of about 0.2 micron. In both gecko and lizard a very high correlation was found between the surface area of perikaryal projections and both the volume and smoothed surface area of the corresponding nerve cell body. The results of the present research agree with those obtained in a previous study on two mammal species (cat and rabbit) and lend further support to the hypothesis advanced in that study; i.e., that perikaryal projections in sensory ganglion neurons are normal formations which maintain the surface-to-volume ratio above the critical level for metabolic exchanges. Perikaryal projections increase the surface area of the nerve cell body by 32.5% in gecko and 30% in lizard, while they increase it by 43% in cat and 39.5% in rabbit. This difference may be related to the lower metabolic rate of the neurons in poikilotherms than in mammals.

A Golgi study of the periaqueductal gray matter in the cat. Neuronal types and their distribution

In Golgi material, the neurons of the periaqueductal gray matter (PAG) of the cat have been classified into five types, according to the following criteria: number of dendrites per cell, characteristics of secondary arborization, frequency of spines and axon caliber. Type 1 cells, which are multipolar and rich in spines are the most frequent, and are probably intranuclear neurons. Type 4 cells have a short axon which ends in the PAG, but they differ from Type 1 in that their dendritic ramification is of a different type and there are few spines. Type 2 and 3 neurons have a thick axon which runs outside the PAG, and dendrites rich in spines. Type 2 cells have more primary dendrites, while Type 3 neurons have dendrites which may spread outside the PAG. Type 5 cells have dendrites with few spines and no secondary ramification. Their thick and long axon projects outside the PAG. Type 2, 3 and 5 cells have been considered projective neurons. The various neuron types are present in every area of the PAG, although in the ventral region there is a predominance of Type 2 and 5 neurons, in the dorsal regions of Type 2 and 3 cells, and in lateral regions of Type 3 and 5 cells. Local intrinsic circuits have been observed in which both the interneurons and the projective, with early axonic collaterals, are involved. The prevalence of neurons to which an afferent role has been attributed (Type 2 and 3 cells) compared with efferent cells (Type 5), is in agreement with hodological studies which indicate that the PAG receives multiple and numerous afferents in comparison with the relatively scarce efferent fibers. These projections can be intensely and deeply elaborated and modulated by means of local intrinsic circuits.

Morpho-quantitative analysis of nuclear inclusions in periaqueductal grey matter neurons in the cat

The morpho-quantitative analysis carried out in the neuronal population of the periaqueductal grey matter of the cat has shown that nuclear inclusions are mainly of the filamentous type and that they are distributed predominantly in the external region, i.e. in the part of the periaqueductal grey matter situated furthest from the cerebral aqueduct, where 30% of the cells contain nuclear inclusions. In the internal region, i.e. in the part nearest the subependymal zone, only 2% of the neurons have nuclear inclusions. The glia in the internal region is more abundant and surrounds each nerve cell body while in the external zone of the periaqueductal grey matter it is scanty and does not delimit the neuronal soma. This difference suggests that there may be a relationship between the incidence of nuclear inclusions and the neuron/glia ratio.

Electron microscope study on neurons occurring in the common peroneal nerve of rat and pigeon

During an electron microscopical study of the common peroneal nerve of albino rats and pigeons, neurons were found along the course of the nerve. Their ultrastructural morphology was studied. On the basis of observed features, such as the occurrence of bare areas of the neurilemma, of thick processes of the perikarya (dendrites), and of synapses on the soma, it appears that these cells are aberrant sympathetic neurons which have migrated to a more distal position than usual.

Cytoarchitecture of the periaqueductal gray matter in the cat: a quantitative Nissl study

We studied the periaqueductal gray matter (PAG) in cresyl-violet-stained serial sections from 5 cats applying quantitative determinations. No significant variations were observed in the cytological aspects in the various sites examined (lateral, ventral and dorsal regions, and external and internal portions). The neuronal density was constant in the different regions, but showed a gradual and significant increase in the most external regions of the PAG. Our findings do not, therefore, confirm the existence in the PAG of subnuclei with a specific cytoarchitecture; this does not, however, rule out the possibility that there are specific regions for connections, histochemical properties or functions.

The ultrastructure of the periaqueductal gray matter of the cat

The neurons of the periaqueductal gray matter (PAG) in cat are generally spindle shaped, small and medium size cells. They have a very high nucleo-cytoplasmic ratio, frequent complex nuclear inclusions and very few axo-somatic contacts. The larger neurons have spine-like extrusions. The neuropil is very extensive, made up mainly by small unmyelinated axons and small dendrites. Also the synaptic boutons are very numerous, and sometimes have particular modalities of contact and arrangement (axo-axonic and dendro-dendritic synapses, 'boutons en passant', and glomerulus-like structures). No significant differences have been observed in the dimensions and shape of the vesicles present in the axo-somatic synapses compared with those present in the neuropil synapses. In both cases pleomorphic vesicles predominate. The particular complexity and abundance of the synaptic contacts in the neuropil suggests that the neuropil is the main site where the afferent inputs to the PAG are modulated and integrated.

Short intrinsic circuit in the periaqueductal gray matter of the cat

In heavily impregnated Golgi material of cat periaqueductal gray matter (PAG), we were able to follow the course of early axon collaterals to their endings on the soma of neighboring neurons. A short intrinsic circuit is therefore created. Combined Golgi and electron microscope observation give evidence of the inhibitory action of this circuit.

A quantitative electron microscope study of the perikaryal projections of sensory ganglion neurons. I. Cat and rabbit

With a quantitative method and serial sections a study was carried out under the electron microscope of the perikaryal projections of the neurons in the thoracic spinal ganglia of cat and rabbit. These projections usually appear as finger-shaped evaginations which run roughly parallel to the surface of the nerve cell body. Their length ranges between 0.3 and 3.25 microns, and they show a nearly circular cross section with a rather uniform transverse diameter having an average value of about 0.2 microns. Both in cat and rabbit a very high correlation was found between the surface area of perikaryal projections and both the volume and smoothed surface area of the corresponding nerve cell body. Perikaryal projections increase the surface area of the nerve cell body by 43% in cat and 39.5% in rabbit. These findings support the idea that perikaryal projections in sensory ganglion neurons are normal formations, which maintain the surface-to-volume ratio above the critical level for metabolic exchanges.

[Our experience with peridural anesthesia in labor]

A clinical study has been carried out on 86 child-bearing mothers, continuous lumbar peridural block being employed, in the light of personal experience, to induce analgesia during labour. The results were positive on the whole as regards duration and the algogenous intensity measured during the dilatation phase and during expulsion.

[Cardiac contusion in closed injuries of the thorax]

Cardiac contusion is a fairly frequent clinical event in closed chest traumas. The diagnostic problems it involves influence prognosis in these patients and, in effect, prevention, speedy recognition and early treatment of the complications of cardiac contusion are essential for therapy. Here the incidence of cardiac contusion in a group of patients with closed chest trauma is analysed and the clinical, diagnostic and therapeutic aspects are examined.

[Lumbar epidural anesthesia in peripheral arteriography]

A brief survey of the difficulties associated with the intra-arterial administration of contrast media during peripheral arteriography is followed by an assessment of anaesthesiological and arteriographic results obtained with lumbar peridural anaesthesia in a group of patients. Complete analgesia, block of the sympathic, and motor block gave particular assistance in the securing of optimum definition of the radiographical picture of the peripheral circulation. These and other advantages offered by peridural anaesthesia suggest that it is a valid technique for peripheral arteriography.