The ascending projections of the dopaminergic neurons of the substantia nigra, zona reticulata: a combined retrograde tracer-immunohistochemical study

The efferent projections of the dopaminergic neurons in the zona reticulata of the substantia nigra were examined using a combined retrograde tracer-immunohistochemical method. These dopamine (DA) neurons were found to project exclusively to striatal targets in a topographically defined fashion. The zona reticulata DA neurons do not innervate mesolimbic or mesocortical dopaminergic terminal fields, nor do they project to the superior colliculus or the ventromedial thalamic nucleus. These data suggest that the dopaminergic neurons of the zona reticulata represent a ventrally placed subset of the nigrostriatal DA cells of the pars compacta.

Human fetal substantia nigra grafted to the dopamine-denervated striatum of immunosuppressed rats: evidence for functional reinnervation

Human fetal substantia nigra tissue, obtained following therapeutic termination of first trimester pregnancies, was grafted to cavities overlying the striatum in ciclosporin-treated rats whose nigrostriatal dopamine system had been removed unilaterally by 6-hydroxydopamine. Tyrosine hydroxylase (TH) immunocytochemistry revealed large numbers of surviving human substantia nigra neurons that matured and formed TH-positive nerve fibers reinnervating the host rat striatum. Apomorphine-induced rotational behavior in grafted animals was reduced by 70-80% in optimal cases 3-5 months after grafting. Thus human fetal dopamine neurons can correct functional deficits in dopamine-denervated rat hosts.

Uptake inhibition protects nigro-striatal dopamine neurons from the neurotoxicity of 1-methyl-4-phenylpyridine (MPP+) in mice

Intracerebroventricular administration of MPP+ to C57 BL/6 mice caused a pronounced depletion of striatal levels of dopamine and 3,4-dihydroxyphenyl-acetic acid ipsilaterally, and a less marked depletion contralaterally. The MPP+-induced reductions were clearly diminished by pretreatment with the dopamine uptake inhibitors mazindol and nomifensine. Similar results were obtained from determinations using tyrosine hydroxylase immunohistochemistry. These results are consistent with the hypothesis that MPTP neurotoxicity is related to the formation of MPP+ from MPTP outside the dopamine neurons and that subsequent uptake of MPP+ into these neurons initiates degeneration.

Cisplatin nephrotoxicity

Cis-dichlorodiammine platinum (II), or cisplatin, has emerged as a principal chemotherapeutic agent in the treatment of otherwise resistant solid tumors and is currently among the most widely used agents in the chemotherapy of cancer. The chief limit to its greater efficacy is its nephrotoxicity, which has made it necessary both to lower its dosage and actively hydrate patients to reduce it. The vulnerability of the kidney to cisplatin is almost certainly related to its primary role in the excretion of cisplatin. Cisplatin enters renal cells by a process that depends on normal oxygen utilization and is specifically inhibited by organic bases. Greater localization of platinum to the S3 segment of the proximal tubules suggests that the vulnerability of this segment may depend on its specific uptake of the drug. The majority of intracellular platinum is bound to macromolecules, including protein and DNA, yet a significant portion of cell platinum is biotransformed to a nonmutagenic and possibly nontoxic compound. Polyuria and hypomagnesemia, which are commonly associated with cisplatin nephrotoxicity, may be due to defects in deep nephron or collecting duct fluid and solute transport. Low single nephron glomerular filtration rates (SNGFR) during early cisplatinum-induced acute renal failure is accompanied by reduced renal blood flow and transglomerular hydrostatic pressure without elevated intratubular hydrostatic pressure, suggesting preglomerular vasoconstriction as an important determinant of renal failure.(ABSTRACT TRUNCATED AT 250 WORDS)

The Apgar score revisited: influence of gestational age

We tested the hypothesis that Apgar scores are in part related to the newborn infant's level of maturity. Seventy-three pregnant women with normal fetuses of gestational age 22 to 42 weeks were studied. Fetal well-being was documented by a prospectively designed recording of pregnancy history, labor complications, and birth outcome, including cord blood pH and base deficit measurements. The 1- and 5-minute Apgar scores were directly related to gestational age. Respiratory efforts, muscle tone, and reflex were the major determinants for a decreasing Apgar score with declining gestational age. We conclude that the 1- and 5-minute Apgar scores are influenced by the infant's level of maturity and that our data may be useful in evaluating the true value of Apgar scores in assessing the fetal and neonatal condition of low birth weight infants.

Sequential multi-agent chemotherapy and whole abdominal irradiation for stage III ovarian carcinoma

Modern therapy for stage III ovarian carcinoma patients usually involves one or more laparotomies with maximal resection of tumor, and intensive multi-agent chemotherapy. However, with long-term follow-up only 10-15% of patients remain free of disease. In the hope of improving outcome, we have treated 17 women with sequential multimodality therapy, including initial surgical resection (if possible), cyclophosphamide-adriamycin +/- cis-platinum, second-look surgery, and whole abdominal irradiation. Seven patients are currently alive without disease, with median follow-up of 52 months since initiation of radiation and 60 months since initiation of chemotherapy. Disease-free survival correlated with residual tumor at the start of radiotherapy: none (4/4); microscopic, less than or equal to 5 mm (3/4); greater than 5 mm or no surgery (0/9). Survival also correlated with tumor grade: grade 1 (2/2); grade 2 (2/3); grade 3 (3/11). Hematological tolerance of radiotherapy was dependent upon the number of chemotherapy cycles: ten of 11 patients receiving less than or equal to eight cycles completed radiotherapy without excessive delay, compared with only one of five receiving greater than eight cycles. There were no treatment-related deaths and only one patient required laparotomy for bowel obstruction. We conclude that intensive multimodal treatment may be tolerated moderately well if the amount of chemotherapy is limited, and that further studies are justified.

Receptor autoradiographical evidence for high densities of 125I-neuropeptide Y binding sites in the nucleus tractus solitarius of the normal male rat

By means of quantitative receptor autoradiography using 125I-neuropeptide Y (125I-NPY) as a radioligand, the distribution of 125I-NPY binding sites has been evaluated in coronal sections at various rostrocaudal levels of the medulla oblongata of the male rat. High densities of neuropeptide Y (NPY) binding sites were demonstrated in the nucleus tractus solitarius (nTS), in the nucleus paratrigeminalis, in the area postrema, in the medial nuclei of the inferior olive and in the substantia gelatinosa of the caudal part of the spinal trigeminal nucleus. Low densities were present in the dorsal motor nucleus of the vagus (dmnX) and in the hypoglossal nucleus. Other regions of the medulla oblongata showed only a very low density or no specific binding of 125I-NPY. These results indicate that the central cardiovascular actions of NPY at least in part may be mediated via an action in the nTS, in this way controlling the baroreceptor reflex activity. Neuropeptide Y mechanisms may also play a role in the regulation of other visceral afferents such as those involved in gastrointestinal control (dmnX) and of cerebellar function (inferior olive). Finally, the results indicate that a high density of NPY immunoreactive terminals in some regions of the medulla oblongata is associated with a low density of high affinity 125I-neuropeptide Y binding sites and vice versa.

Migration of an extradural catheter into the subdural space. A case report

After repeated, successful extradural injections in a parturient, the extradural catheter migrated into the subdural space. The injection of 3% chloroprocaine 10 ml resulted in an extensive block, which extended to the cranial nerves and paralysed the respiratory muscles. The position of the catheter tip was confirmed by fluoroscopy. Subdural injection should always be suspected when tests for subarachnoid injection are negative, but an extensive block occurs gradually within 15-20 min. Respiration and circulation should be supported until the block regresses.

Striato-nigral dynorphin and substance P pathways in the rat. I. Biochemical and immunohistochemical studies

The effect of striatal ibotenic acid lesions on dynorphin-, substance P- and enkephalin-like immunoreactivities in the substantia nigra has been studied with immunohistochemistry as well as biochemistry. A comparison was made with the effects produced by intranigral ibotenic acid lesion and by 6-hydroxy-dopamine injection into the medial forebrain bundle. In addition, the effect of the striatal lesions on nigral glutamic acid decarboxylase (GAD)-positive structures was analysed with immunohistochemistry. The effect of the lesions was analysed functionally in the Ungerstedt rotational model, in order to obtain a preliminary evaluation of the extent of the lesions. The striatal lesions produced a parallel depletion of dynorphin and substance P levels in the substantia nigra, pars reticulata, ipsilateral to the treated side, which was dependent upon the extent and location of the lesion. Ibotenic acid lesions into the tail and the corpus of the striatum produced stronger nigral-peptide depletion than lesions in the head and the corpus of the striatum. Comparison of placement of lesions and localization of depleted area in the substantia nigra revealed a topographical relationship. Furthermore, the nigral depletion patterns of dynorphin and substance P were similar. The immunohistochemical analysis revealed that also GAD-positive fibers in the pars reticulata to a large extent disappeared after striatal lesions, in parallel to the dynorphin- and substance P-positive fibers. However, the depletion was less pronounced for GAD than for the peptides, probably related to presence of local GABA neurons in the zona reticulata of the substantia nigra. These results indicate that with the types of lesion used in this study it is not possible to provide evidence for a differential localization within the striatum of dynorphin-, substance P- and GABA-positive cell bodies projecting to the substantia nigra. The radioimmunoassay showed that (Leu)- but not (Met)-enkephalin was affected to the same extent as the dynorphin peptides, supporting the view that (Leu)-enkephalin in the pars reticulata of the substantia nigra is derived from proenkephalin B and not from proenkephalin A. In the immunohistochemical analysis (Met)-enkephalin-like immunoreactivity could only be detected in the pars compacta of the substantia nigra and did not seem to be affected by any of the lesions. The striatal lesions produced a behavioural asymmetry, which could be disclosed by stimulating the rats with apomorphine, which produced ipsilateral rotation.(ABSTRACT TRUNCATED AT 400 WORDS)

Growth of human pheochromocytomas in the anterior eye chamber of the rat. A histochemical study on amine and peptide content of pheochromocytoma tumour cells

Tissue pieces from seven benign human pheochromocytomas have been successfully transplanted to the anterior eye chamber of cyclosporin-treated rats. In vivo observations showed that 74-99% of the tumour transplants were vascularized within one to two days after transplantation. No increase in the size of the transplants was noted during the observation period (1-4 weeks). Tumour transplants grown in non-immunosuppressed rats were initially vascularized but rejection started to occur one week after transplantation. Histochemical analysis of tumour transplants grown in immunosuppressed rats demonstrated numerous tumour cells with strong catecholamine fluorescence, some of which formed long cell processes on the host iris. Immunocytochemical analysis of tumour transplants demonstrated positively labelled tumour cells after incubation with antisera against neuropeptide Y, enkephalin, vasoactive intestinal polypeptide, somatostatin, substance P, dopamine-beta-hydroxylase, tyrosine hydroxylase and serotonin. A similar histochemical and immunocytochemical pattern was observed in primary tumours but tumour cells sending out cell processes were observed less frequently. Human pheochromocytomas may thus be successfully grown in oculo in cyclosporin-treated rats. This may prove to be a suitable model for the study of storage and release of catecholamines and neuropeptides from pheochromocytoma tumour cells.

[Spontaneous aortocaval fistulization caused by rupture of an abdominal aortic aneurysm: apropos of 3 case reports]

During the last six years, the authors treated 44 patients for a ruptured abdominal aneurysm. Three of these patients had a spontaneous aorto-caval fistula and their clinical cases are described. The special diagnostical and therapeutical features of this rare complication are emphasized.

LHRH and catecholamine neuronal systems in the olfactory bulb of the mouse

The luteinizing-hormone-releasing hormone (LHRH) components of the mouse olfactory system were studied by using the indirect immunohistofluorescence technique. LHRH-positive cell bodies were found in both the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB); two distinct cell groups were found--one located adjacent to the AOB in the dorsal part of the MOB and a second in the superficial ventromedial aspect of the MOB. LHRH-positive fibers were found predominantly in the posterior half of the main olfactory bulb innervating the olfactory nerve layer, the glomerular layer, the external plexiform layer, and the mitral cell layer, and small numbers innervated the AOB. The greatest density of LHRH-immunoreactive fibers was seen adjacent to the AOB where one group of LHRH-positive cells was noted. Sections adjacent to those stained with LHRH antibody were analysed for tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH). The TH staining was intense for both cells and fibers in the glomerular layer of the MOB. In the AOB lower numbers of cell bodies and fibers were seen in the glomerular layer. The internal granular layer and internal plexiform layers were both stained, the internal granular layer showing more intensely fluorescent fibers with a higher density. Since no overlapping DBH-positive fibers were found here, these TH-positive nerve endings may be dopaminergic. DBH staining was confined to sparse networks of weakly fluorescent fibers with the highest numbers in the internal plexiform layer of the AOB and fewer fibers in the external plexiform, rostral, and granular layers of the MOB. Elution-restaining experiments revealed that the LHRH-positive and TH-positive elements represent different cell populations.

Tyrosine 3-hydroxylase in rat brain and adrenal medulla: hybridization histochemistry and immunohistochemistry combined with retrograde tracing

Rat brain and adrenal gland were analyzed by hybridization histochemistry using an RNA probe complementary to mRNA for tyrosine 3-hydroxylase (TyrOHase; tyrosine 3-monooxygenase, EC 1.14.16.2), by immunohistochemistry using TyrOHase antiserum, and by retrograde tracing using the fluorescent compound Fast blue. Cell bodies in the ventral mesencephalon contained mRNA for TyrOHase, and these cells were also TyrOHase immunoreactive. After injection of Fast blue into the striatum, such double-labeled cells in addition contained the retrograde tracer, showing that these cells send axonal projections to the injection site. These results show that hybridization histochemistry can be used to identify transmitter-specific neuron populations and that their projections can be established.

Topography of NPY-, somatostatin-, and VIP-immunoreactive, neuronal subpopulations in the guinea pig celiac-superior mesenteric ganglion and their projection to the pylorus

The topography of the peptidergic neuronal subpopulations in the guinea pig celiac-superior mesenteric ganglion was studied analyzing the distribution of immunoreactivity to neuropeptide Y (NPY), somatostatin (SOM), and vasoactive intestinal polypeptide (VIP)/polypeptide HI (PHI). For comparison, the ganglion was also studied using antisera against the 2 catecholamine-synthesizing enzymes tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH). Approximately 65% of the neuronal cell bodies contained NPY-like immunoreactivity (NPY-LI), whereas 25% of the principal ganglion cells contained SOM-like immunoreactivity (SOM-LI). Though occasional cells were found to contain both NPY-LI and SOM-LI, these peptides had a complementary distribution in the ganglion, with NPY cells in the celiac poles and SOM cells in the superior mesenteric pole. The vast majority of both the NPY- and SOM-positive cells also contained TH-like immunoreactivity (TH-LI), confirming their catecholaminergic, presumably noradrenergic, nature. Some noradrenergic neurons seemed to lack NPY- and SOM-LI. Small numbers of VIP/PHI-containing cell bodies were found in areas where the NPY-immunoreactive neurons predominated. Many of the VIP/PHI-positive cells contained NPY-LI and occasionally also TH-LI. The immunohistochemical markers were also observed in fibers. Thus, a comparatively weak NPY-LI was seen in smooth fibers, probably representing axons and axon bundles. SOM-LI was seen in a similar type of fiber but also in more strongly fluorescent fibers with a varicose appearance. The latter fibers were observed only in the SOM-dominated part of the ganglion, often surrounding the ganglion cells. Varicose fibers with a similar distribution containing DBH-like immunoreactivity (DBH-LI) were also seen. In addition, DBH- and TH-LI were seen in smooth axonlike processes. VIP-positive fibers exhibited a very dense fiber network, almost exclusively related to the SOM cell-dominated part of the ganglion. The projection of the postganglionic sympathetic neurons was studied with special reference to the pylorus using a combination of retrograde axonal tracing and indirect immunofluorescence techniques. Seventy-two hours after injection of the fluorescent tracer Fast Blue into the pyloric sphincter, labeled neurons were found in the ganglion. By comparing the Fast Blue-labeled cells with the immunoreactive cell bodies, neurons containing both dye and NPY- or SOM-LI were observed. In elution-restaining experiments, it was established that the majority of these cells were also immunoreactive to TH, indicating that they produce noradrenaline.(ABSTRACT TRUNCATED AT 400 WORDS)

Preferential vulnerability of A8 dopamine neurons in the primate to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

Immunohistochemical examination of the midbrain of vervet monkeys treated with MPTP revealed a marked loss of dopaminergic neurons in the lateral, but not medial, region of the A8 dopamine (DA) cell group. In the same animals, the number of DA neurons in the substantia nigra was only slightly decreased. Biochemical assessment revealed a marked (greater than 85%) depletion of DA in the striatum. However, in the DA cell body regions significant decreases in DA and homovanillic acid were observed only in the lateral A8 region, and not in the medial A8 region or substantia nigra. These data suggest that those A8 DA neurons which project to the striatum are preferentially vulnerable to MPTP.

[Arteriovenous fistulas. Apropos of 5 cases]

An arterio-venous fistula can be defined as being a vascular anomaly in which there are one or more direct or indirect communications between an artery and a vein, without the capillary network being involved, this latter therefore being short-circuited. After the presentation of five cases, the authors review the literature on the subject.

Computer corner #14. ORTHOX: computerized measurement of x-ray films in orthopaedic surgery

We believe that ORTHOX is a practical solution for the evaluation of x-rays giving a fast and accurate reading, that can be performed by every physician, even if his orthopaedic experience is still limited.

'Neuropeptide tyrosine' (NPY) is co-stored with noradrenaline in vascular but not in parenchymal sympathetic nerves of brown adipose tissue

By using immunohistochemistry it is shown that both the parenchymal and vascular sympathetic innervation in the interscapular depot of brown adipose tissue in the rat contain the catecholamine-synthesizing enzyme tyrosine-hydroxylase (TH). In contrast, 'neuropeptide tyrosine' (NPY) is selectively present in the vascular sympathetic nerves of the tissue--but not in nerves around brown fat cells. This is consistent with the presence of two populations of neurons (containing either TH alone or TH plus NPY) in the stellate ganglion, which is the probable origin of the sympathetic nerves in the interscapular brown adipose tissue. Furthermore, the perivascular NPY-positive nerves in the brown adipose tissue disappeared after 6-hydroxydopamine treatment, demonstrating their noradrenergic nature. Taken together, these findings suggest that sympathetic nerves to blood vessels and brown fat cells represent two separate subpopulations of autonomic neurons.

Activation of alpha 2-adrenoreceptors enhances haloperidol-induced suppression of operant behavior

Inhibition of catecholamine synthesis by alpha-methyl paratyrosine (alpha-MT) was previously shown to potentiate the behavioral suppression caused by dopamine-receptor antagonists. This effect of alpha-MT is in all probability due to inhibition of the compensatory increase in dopamine turnover induced by the dopamine receptor antagonists. In the present study we investigated the effect of the alpha 2-adrenoreceptor agonist clonidine on the haloperidol-induced suppression of food-reinforced lever-pressing behavior (fixed ratio 40:1) in rats. Small behaviorally inactive doses of clonidine were found, in analogy with alpha-MT, to enhance the haloperidol-induced suppression of the lever-pressing behavior. The haloperidol-induced increase in dopamine synthesis (measured as the accumulation of DOPA after inhibition of aromatic amino acid decarboxylate) was antagonized by clonidine in the striatum as well as in the dopamine rich limbic regions. Prazosin, a selective alpha 1-adrenoreceptor antagonist had no effect on the clonidine induced behavioral changes. Idazoxane, a selective alpha 2-adrenoreceptor antagonist, counteracted both the behavioral and biochemical effects of clonidine, indicating that these effects of clonidine are mediated via its action on alpha 2-adrenoreceptors. The present findings provide support for the notion that alpha 2-adrenoreceptors may participate in the regulation of nigro-striatal as well as meso-limbic dopaminergic activity. It is suggested that alpha 2-adrenoreceptor agents, especially in combination with classical antipsychotics, might be of therapeutic value in the treatment of disorders associated with abnormal dopaminergic activity.

A monoclonal antibody against tyrosine hydroxylase: application in light and electron microscopy

The catecholaminergic neurons of the nervous system have been studied histochemically with fluorescent derivatives of catecholamines and immunocytochemically using antibodies against their biosynthetic enzymes. The immunocytochemical techniques yield permanent preparations and make possible ultrastructural studies and combined applications with other procedures. In this report, we describe the production and application of a high-affinity mouse monoclonal antibody against the rate-limiting enzyme in the biosynthetic pathway of the catecholamines, tyrosine hydroxylase. This antibody, coded TOHA1.1, has been used successfully to stain tyrosine hydroxylase immunoreactive sites in the known catecholaminergic neurons and fiber systems of rat brain in both light and electron microscopy. It has also been demonstrated that TOH A1.1 will immunoprecipitate phosphorylated tyrosine hydroxylase.

Receptor reserve at striatal dopamine autoreceptors: implications for selectivity of dopamine agonists

The dose response curve for apomorphine reversal of gamma-butyrolactone (GBL)-induced L-DOPA accumulation in rat striatum was shifted almost 6-fold to the right after partial irreversible blockade (83%) of dopamine (DA) autoreceptors with N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ); however, the maximal response was not reduced. In contrast, the major effect of a similar degree of irreversible blockade (86%) on the dose-response curve for the autoreceptor-selective agent EMD 23,448 was a reduction in maximal response (60% of control), indicating that EMD 23,448 is a partial agonist. A large receptor reserve therefore exists at the DA autoreceptor, which may explain in part why many DA agonists are more potent in models pre- than postsynaptic receptor activation.

Dopamine agonist induced self-mutilative biting behavior in monkeys with unilateral ventromedial tegmental lesions of the brainstem: possible pharmacological model for Lesch-Nyhan syndrome

We have investigated the effects of various dopamine (DA) agonists on induction of abnormal involuntary movements (AIM) in a group of monkeys which had denervated nigro-striatal DA neurons for 10-14 years rendered by a unilateral surgical ventromedial tegmental (VMT) lesion of the brainstem. The surgical lesions were placed when the monkeys were 2-4 years old. The administration of mixed DA agonists, such as L-DOPA, apomorphine (Apo) and abeorphine 201-678, elicit a self-mutilative biting behavior (SMB) of the forelimb digits contralateral to the lesion, and spasticity of the contralateral hindlimb. These dysfunctions resemble, in some aspects, the neurological disturbances associated with Lesch-Nyhan syndrome. The SMB behavior was elicited by mixed DA agonists which predominantly stimulate D1, but not D2 DA receptors, and was prevented or abolished by the D1 DA antagonist SCH 23390 or by the D1 and D2 DA antagonist fluphenazine (Flu), but not by the D2 antagonist (+/-)sulpiride. These results suggest that DA agonist-induced SMB behavior is mediated by D1 and/or by both D1 and D2 DA receptor pathways. To study the relationships between HPRT, the defective enzyme in Lesch-Nyhan syndrome, and the DA neuronal systems, we have measured the effects of nigro-striatal DA degeneration and intrastriatal neuronal degeneration on HPRT activity. The unilateral 6-OHDA-induced nigro-striatal DA degeneration does not significantly alter the HPRT activity on the lesioned side of the striatum, while the quinolinic acid-induced intrastriatal neuronal degeneration significantly reduces the enzyme activity. These results suggest that HPRT is localized on intrastriatal neurons which are also known to contain DA receptors. It is postulated that HPRT deficiency in Lesch-Nyhan syndrome results in abnormal guanine nucleotide metabolism which may affect the regulation of DA receptors.

Expression and development of phenylethanolamine N-methyltransferase (PNMT) in rat brain stem: studies with glucocorticoids

To study the differentiation of adrenergic (epinephrine-synthesizing) neurons in brain, the initial appearance and ontogeny of phenylethanolamine N-methyltransferase (PNMT), a specific marker of the adrenergic phenotype, were studied with immunocytochemistry and catalytic assay. The appearance of immunoreactivity to dopamine beta-hydroxylase (DBH-IR), an enzyme common to the noradrenergic and adrenergic phenotypes, was also studied. DBH-IR was initially observed on embryonic Day 13 (E13) in cells located on the ventrolateral floor and wall of the rhombencephalon. A day later (E14), PNMT-IR cells and PNMT catalytic activity were observed in the rhombencephalon suggesting that, as in the adrenal gland, noradrenergic expression precedes adrenergic expression. The PNMT-IR cells were presumed to be precursors of C1 neurons since they were located in the ventrolateral medulla oblongata. Cells located in the wall of the medulla which appeared to be migrating ventrally to the C1 group also contained PNMT-IR. On E15, cells which had PNMT-IR processes coursing through the germinal zone were observed dorsally near the fourth ventricle. Although the location of the C1 cell group was apparent when PNMT was initially expressed, the dorsal C2 and C3 adrenergic cell groups were not evident until late in gestation on E19. Even in the term embryo there appeared to be PNMT-IR cells which had not yet reached their final destination. On E14 and E15, PNMT-IR cells were also observed on the floor of the pons just rostral to the pontine flexure. However, these were not observed in older embryos, suggesting that transient expression of PNMT occurs in brain, as well as in the periphery. To determine whether glucocorticoids regulate brain PNMT, we examined the effects of altered glucocorticoid levels. In contrast to PNMT in the sympathetic nervous system, PNMT activity in medulla oblongata was not affected in neonates or adults by the decrease in glucocorticoids following adrenalectomy or hypophysectomy. Conversely, elevation of glucocorticoids by hormonal treatment did not alter PNMT in neonates. Notably, however, treatment of pregnant rats with dexamethasone on E18-E21, but not earlier, increased PNMT activity in the fetal brain stem. These observations suggest that PNMT expression and development is regulated by different factors in cells derived from neural crest and tube. PNMT is expressed earlier in brain than in adrenal and sympathetic ganglia. Further, the development of PNMT in the periphery, but not in the brain, is dependent on maintenance of physiological levels of glucocorticoids.(ABSTRACT TRUNCATED AT 400 WORDS)

[Clinical diagnosis of pulmonary embolism]

Pulmonary embolism, a major complication of thromboembolic disease, remains an important cause of mortality, both in surgical and medical practice. In recent literature, one finds two different currents: the first one asserts that pulmonary embolism is overdiagnosed and, therefore, "overtreated" with iatrogenic hemorrhagic complications, when other authors assert that pulmonary embolism is underdiagnosed and "undertreated". It is obvious that clinical diagnosis of non massive, acute pulmonary embolism remains difficult and that the classical triad pleuritic chest pain, hemoptysis and signs of deep venous thrombosis is not frequently found. The clinician should be attentive to the different symptoms and clinical signs which might arouse a suspicion of pulmonary embolism. A large range of investigations is available to confirm the clinical diagnosis. In deep venous thrombosis preceding or accompanying pulmonary embolism, treatment should be instituted at the first signs of venous attack. A precise diagnosis will secondarily be confirmed by phlebography. Any delay in effective early treatment of thromboembolic disease will increase the risk of pulmonary embolism and of the mortality inherent in this dreadful complication.