Increase in myocardial interstitial adenosine and net lactate production in brain-dead pigs: an in vivo microdialysis study.

BACKGROUND: Brain death-related cardiovascular dysfunction has been documented; however, its mechanisms remain poorly understood. We investigated changes in myocardial function and metabolism in brain-dead and control pigs. METHODS: Heart rate, systolic (SAP) and mean (MAP) arterial pressure, left ventricular (LV) dP/dtmax, rate-pressure product, cardiac output (CO), left anterior descending coronary artery blood flow, lactate metabolism, and interstitial myocardial purine metabolite concentrations, monitored by cardiac microdialysis, were studied. A volume expansion protocol was performed at the end of the study. RESULTS: After brain death, a transient increase in heart rate (from 90 [67-120] to 158 [120-200] beats/min) (median, with range in brackets), MAP (82 [74-103] to 117 [85-142] mmHg), LV dP/dtmax (1750 [1100-2100] to 5150 [4000-62,000] mmHg x sec(-1), rate-pressure product (9100 [7700-9700] beats mmHg/min to 22,750 [20,000-26,000] beats mmHg/min), CO (2.2 [2.0-4.0] to 3.3 [3.0-6.0] L/min), and a limited increase in left anterior descending coronary artery blood flow (40 [30-60] to 72 [50-85] ml/min) were observed. Net myocardial lactate production occurred (27 [4-40] to -22 [-28, -11] mg/L, P<0.05) and persisted for 2 hr. A 6-7-fold increase in adenosine dialysate concentration was observed after brain death induction (2.9 [1.0-5.8] to 15.8 [7.0-50.7] micromol/L), followed by a slow decline. Volume expansion significantly increased MAP, CO, and LV dP/dtmax in control animals, but decreased LV dP/dtmax and slightly increased CO in brain-dead animals. A significant increase in adenosine concentration was observed in both groups, with higher levels (P<0.05) in brain-dead animals. CONCLUSIONS: Brain death increased oxygen demand in the presence of a limited increase in coronary blood flow, resulting in net myocardial lactate production and increased interstitial adenosine concentration consistent with an imbalance between myocardial oxygen demand and supply. This may have contributed to the early impairment of cardiac function in brain-dead animals revealed by rapid volume infusion.

Angiotensinogen in the developing rat fetal hindbrain and spinal cord from 18th to 20th day of gestation: an immunocytochemical study.

We have detected angiotensinogen immunoreactivity in the hindbrain and in the spinal cord of rat fetuses during the 18th to 20th day of gestation. In the 18th-day fetus, a few immunoreactive angiotensinogen cells are localized in precise brain areas. Their number sharply increase during the 19th and 20th day gestation period when there is an active cell differentiation and cell growth. These observations suggest a role of the renin-angiotensinogen system during cell growth and cell differentiation.

[Effects of sleep on ovary development during hibernation and aestivation in the dormouse (Eliomys quercinus L.)(author's transl)]. / Influence du sommeil sur l'évolution de l'ovaire au cours des périodes hivernale et estivale chez le lérot

Hibernation does not correspond to a period of rest of the ovary, nor to the prolongation of a period of anoestrus. Hibernation is necessary for the normal course of the period of genital activity. Its suppression tends to modify more or less severely the physiological equilibrium implicated in the control of genital activities. However, the animal can find a more or less normal rythm even if is deprived of hibernation during the course of a second year. Prolongation of hibernation in hemicastrated animals during the entire period of genital activity suppresses the ovular discharge and the ovulating secretion of FSH and LH, without affecting the tonic secretions of FSH. It inhibits the phenomenon of compensatory hypertrophy. However, in hemicastrated animals deprived of hibernation, the reaction to hemicastration does not take place nor during anoestrus nor during mid-december or mid-march but only when the period of genital activity begins again.

Neuronal systems immunologically related to the somatostatin system in the garden dormouse.

Cells and fibers containing somatostain (SRIF) or SRIF-like peptides were detected immunocytochemically in the brain of the garden dormouse (Eliomys quercinus L.). The periventricular preoptic nucleus and the paraventricular nucleus encompass a component of the SRIF-immunoreactive hypothalamo-infundibular and hypothalamo-neurohypophyseal systems. The suprachiastmatic, ventromedial and arcuate nuclei contain a number of SRIF-positive cells and receive a rich SRIF innervation. The extrahypothalamic systems containing SRIF can be subdivided into the following groups: (1) Afferents, the cellular origin of which is not always clearly evident, i.e., fibers of the septum, the lateral preoptic area, the thalamus, the superior olivary nucleus, the mesencephalic gray matter, and the subfornical organ; (2) dispersed cells with short projections (neocortex, caudate nucleus, putamen); (3) scattered cells with short projections (nucleus accumbens) or innervating remote territories (nucleaus interpeduncularis); (4) vascular organ of the lamina terminalis, a neurohemal area comparable to the median eminence. These observations lead to a theory of a functional bipotentiality of the somatostatin molecule. Immunocytological results depend on the antisera employed, the type of fixation and the experimental conditions. Adrenalectomy is followed by an accumulation of immunoreactive material in all SRIF-containing systems of the brain. These results clearly indicate the SRIF participates in the function of the CRF-ACTH-adrenal axis. The endocrine disturbance induced by adrenalectomy appears to modify the activity of both the neurohormonal and neuromodulator components of the SRIF system.

[Immunocytologic detection of peptides immunologically related to LRH and to SRIF in the garden dormouse under various conditions]. / Détection immunocytologique de peptides immunologiquement apparentés au LRH et au SRIF chez le lérot dans différentes conditions

Immunocytologic technics have allowed us to detect appreciable and progressively increasing amounts of LRH and of SRIF in the median eminence of the dormouse during hibernation at 6 degrees C. In animals conditioned to darkness at 22 degrees C with the ovarian involution that is very important, there exists a nearly total disappearance of LRH while the amount of SRIF remains high. On the contrary permanent lighting at 22 degrees C responsible of an important reactivation of the genital sphere provoques a massive accumulation of LHR in the median eminence; SRIF is present in large amounts during the first weeks but diminishes of the experience is prolonged.

[Effects of blinding by bilateral orbital enucleation on the ultrastructure of the pineal gland in the female garden dormouse (Eliomys quercinus L.). Correlations with the hypothalamo-pituitary-ovarian axis]. / Effets de l'énucléation oculaire bilatérale sur l'ultrastructure de l'épiphyse chez la femelle du lérot (Eliomys quercinus L.). Corrélations avec l'axe hypothalamo-hypophyso-ovarien.

Dormice were blinded by bilateral enucleation in December before hibernation or in March at the end of hibernation and were then studied in July and October. All the animals stayed in permanent anoestrus even at long-term. The ultrastructure of the pinealocyte was very characteristic, presenting typical elements of both hibernal anoestrus and sexual activation. Two organelles were well developed in enucleated dormice: reticulo-endoplasmic vacuoles and liposomes whose development seemed to be associated with protein secretions and pineal serotonine level, respectively. The hypothalamo-hypophyseal characterististics of the enucleated animals were also surprising: the hypothalamic LHRH load was important and hypophyseal gonadotropic cell development normal although the ovaries were hypoactive. The dormouse has a seasonal sexual cycle which cannot be realized without light. Pineal ultrastructural findings correlated with the activity of the hypothalamo-pituitary-ovarian axis lead us to think that this endocrine gland plays a role in the action of light on sexual activity.

Effect of castration and adrenalectomy on the ultrastructure of pinealocytes in the female garden dormouse (Eliomys quericnus L.) under different conditions of lighting and temperature during the normal period of hibernation.

The ultrastructure of the female garden dormouse pinealocyte has been studied during the period of hibernation in normal, castrated, castrated and adrenalectomized hibernant animals and non-hibernant ones living under a L-D = 10-14 photoperiodicity or continuous lighting. Continuous illumination on the one hand, and gonad and adrenalectomy on the other, have similar effects on the ultrastructure of pinealocytes. Especially a striking reduction of liposomes, an increased development of the Golgi apparatus and of cisterns formed by the rough endoplasmic reticulum were observed. The observations suggest that the liposomes are involved in a perhaps indoleaminergic antigonadotropic secretory process whereas the peculiar dilated cisterns of the rough endoplasmic reticulum may be related with a pineal polypeptidergic gonadotropic secretory process.

[Influence of the photoperiod on the ultrastructure of the pineal gland before and during the seasonal genital cycle in the female garden dormouse (Eliomys quercinus L.) (author's transl)]. / Influence de la photopériode sur l'ultrastructure de l'épiphyse avant et pendant la phase génitale saisonnière chez la femelle du lérot (Eliomys quercinus).

The pinealocyte of the female garden dormouse presents ultrastructural characteristics correlated with the sexual cycle. In winter, during the period of sexual quiescence, the pinealocyte is very rich in liposomes, myelinic bodies and lysosomes; the same holds during the summer quiescence state. These organelles and a great number of intracellular vacuoles are very well developed in dormice artificially maintained in anoestrous during the normal sexual activity period by light deprivation. In spring liposomes are strongly reduced in animals that are awake and sexually active, whereas the number of "synaptic ribbons" and of densecored vesicles increases. This ultrastructural aspect can be obtained during winter quiescence in animals living at 22 degrees C, under continuous light, and showing early sexual activation. If illumination is prolonged over the seasonal sexual phase dilated cisterns of granular endoplasmic reticulum, filled with proteinaceous material, appear in the cell. It seems that light no more activates, but inhibits gonadostimulator mechanisms. The pinealocyte's ultrastructural elements which are characteristic of a definite sexual state generally develop before this state is fully established. Actually, the functional significance of these organelles is not known.

The renin-angiotensin system in the rat brain. Immunocytochemical localization of angiotensinogen in glial cells and neurons.

The distribution of angiotensinogen containing cells was determined in the brain of rats using immunocytochemistry. Specific angiotensinogen immunoreactivity is demonstrated both in glial cells and neurons throughout the brain, except the neocortical and cerebellar territories. Positive neurons are easily and invariably detected in female brains, and haphazardly in male brain (sex hormone dependent). Angiotensinogen immunoreactivity in male brain neurons can be induced by water deprivation or binephrectomy in some areas and particularly in paraventricular nuclei. Finally, the highest concentrations of positive neurons are found in the anterior and lateral hypothalamus, preoptic area, amygdala and some well known nuclei of the mesencephalon and the brainstem. Our results confirm the wide distribution of angiotensinogen mRNA in the brain reported recently by Lynch et al. (1987). Thus the demonstration of angiotensinogen in neurons and glial cells allows a greater understanding of the biochemical and physiological data in accordance with multiple brain renin angiotensin systems.

Histoimmunological identification of a prolactin-like substance in rodent testis.

Anti-rat prolactin (PRL) antibodies were localized by histoimmunological methods in the cytoplasm of testicular interstitial cells, Sertoli cells, spermatogonia and primary spermatocytes of the rat and mouse. Control of specificity by affinity chromatography methods showed this PRL-like material to be non-specific in these testicular tissues, but specific in adenohypophyseal cells. These results are discussed.

Demonstration by immunocytochemical staining of a somatostatin-28-(1-14)-like peptide in planarians (Plathyhelminthes Turbellaria Tricladida).

A specific polyclonal antiserum directed against the somatostatin-28(1-14) of vertebrates was applied to sections of the planarians Dugesia lugubris and Dendrocoelum lacteum. This made it possible to reveal nerve cells and processes specifically both in cerebral ganglia and in ventral nerve cords. The phylogenetic importance of this demonstration is pointed out.

Immunolocalization of albumin and transferrin in germ cells and Sertoli cells during rat gonadal morphogenesis and postnatal development of the testis.

The localization of albumin and transferrin was examined immunohistochemically in germ cells and Sertoli cells during rat gonadal morphogenesis and postnatal development of the testis. These proteins appeared as early as the 13th day of gestation in migrating primordial germ cells before Sertoli cell differentiation. In the fetal testis, strong immunoreactivity was only detected in the gonocytes. In the prepubertal testis, spermatogonia, primary spermatocytes, and some Sertoli cells accumulate albumin and transferrin. At puberty, different patterns of immunostaining of the germ cells were observed at the various stages of the cycle of the seminiferous epithelium. Diplotene spermatocytes at stage XIII, spermatocytes in division at stage XIV, and round spermatids at stages IV-VIII showed maximal staining. Labeling was evident in the cytoplasm of adult Sertoli cells. Albumin and transferrin staining patterns paralleled each other during ontogenesis.

Immunolocalization of some plasmatic proteins in basement membranes during earliest rat morphogenesis with special reference to the gonadal differentiation.

Rat albumin, transferrin, angiotensinogen and T kininogen were examined immunohistochemically in the epithelial basement membranes (BMs) during the earliest rat morphogenesis. As a specific marker for BMs, laminin was used. Albumin and transferrin immunostaining appeared as early as the 11th day of gestation in all epithelial BMs. In 13-day-old mesonephric-gonadal complex, just after the onset of the sexual cord differentiation, all BMs were weakly stained. One day later, a stronger immunoreactivity was distributed along the coelomic epithelium, the Wolffian duct, the mesonephric tubules, the differentiating sexual cords and the blood vessels. The epidermal BM and all epithelial BMs of differentiating organs are also immunoreactive. The accumulation of albumin and transferrin in the BMs is probably the result of a strong release of these two major liver proteins in the embryonic blood and their diffusion in extracellular spaces. At these stages, the lack of angiotensinogen and T kininogen BM labeling is consistent with their low hepatic and plasmatic concentrations. During embryogenesis, some plasma proteins are probably trapped in the epithelial BMs and not produced by local cells.

[Demonstration of peptides immunologically related SRIF, neurophysins and angiotensin in the planarian Dugesia lugubris (Platyhelminths,Turbellaria) (author's transl)]. / Mise en évidence de peptides immunologiquement apparentés au SRIF, à l'ACTH, aux neurophysines et à l'angiotensine II chez la planaire Dugesia lugubris (Plathelminthes, Turbellariés).

Several antisera, specific to the neuropeptides of Vertebrates, were applied to frontal sections of the planarian Dugesia lugubris. Five of them enabled to show specific neurones: anti-sera anti-SRIF, anti-neurophysines, anti-ACTH 17-39, anti-ACTH4-10 and anti-angiotensin II. The positive perikarya were situated mainly at the margin of the cerebroïd ganglia and the nerve cords, at all levels of the animal. Nerves processes were detected in the central nervous system and in the surrounding areas.

Differential distribution of immunoreactive angiotensinogen in the hind-brain and spinal cord of neonatal and adult rats.

The present communication deals with the cytochemical localization of angiotensinogen (ATG) immunoactivity in the hind-brain and spinal cord of neonatal (1-day-old) and adult (3-month-old pregnant) female rats. In the neonatal hind-brain, the immunoreactive cells were more numerous than in that of adult rats. In the adult rat hind-brain, the number of ATG-positive cells was quite limited in each nucleus. Further, in some nuclei, only neurons or neuroglia were positive, while in others the immunoactivity was observed in both the components. Spinal cords of neonatal rats showed a few undifferentiated ATG-positive cells in the grey matter. Contrary to this, the spinal cord of adult animals contained numerous immunoreactive glial cells in the grey matter, fasciculus cuneatus and fasciculus gracilis. Immunoactivity in the neurons was localized in the Nissl bodies.

Immunolocalization of type IV collagen and laminin during rat gonadal morphogenesis and postnatal development of the testis and epididymis.

The distribution of type IV collagen and laminin was studied by immunocytochemistry during rat gonadal morphogenesis and postnatal development of the testis and epididymis. Immunostaining appeared as early as the 12th day of gestation along the basement membranes of the mesonephric-gonadal complex. The connection between some mesonephric tubules and coelomic epithelium was seen between the 12th and 13th day of gestation. Discontinuous immunostained basement membranes delineated the differentiating sexual cords in 13-day-old fetuses; this process probably began in the inner part of the gonadal ridge. The seminiferous cords surrounded by a continuous immunoreactive basement membrane are separated from the coelomic epithelium by the differentiating tunica albuginea in 14-day-old fetuses. During the postnatal maturation of epididymis and testis, the differentiation of peritubular cells is accompanied by a progressive organisation of the extracellular matrix into a continuous basement membrane. This change is associated with a gradual condensation of peritubular cells inducing an increase of immunostaining. In adult animals, the tubular wall of epididymis is thicker than the lamina propria of seminiferous tubules. Both type IV collagen and laminin immunostaining paralleled during ontogenesis at the light-microscope level.