Immuno-cytologic study of hypothalamic LH-RH neurons of the human fetus]

The immunocytological study of LH-RH producing neurons was carried out on 3 newborns and 14 fetuses (from 10 to 36 weeks of age). Perikarya and fibers which were immunoreactive to anti-LH-RH IS were revealed by IF or IE in all the hypothalamus beginning with the 13th week. Important variations in neurons staining may translate "physiological" differences in their LH-RH charge but can be also the result of the diverse technical conditions. In three 16-week-old female fetuses, the large number of neurons (more than 150 per hypothalamus) permitted a good topographical and morphological study of them. They are scattered in vast areas of the anterior hypothalamus (lamina terminalis (LT) and septum), mediobasal and premammillary hypothalamus. The fibers which are particularly immunoreactive in semi-thin sections form a large hypothalamo-infundibular contingent in the posterior lip of the ME where they give rise to collaterals that terminate in contact with the capillaries of the mantelplexus, this taking place both before and after the apparition of the intra-eminential loops at the 16th week. Numerous in the LT, they terminate around the deep capillaries of the vascular organ or in contact with the ependymal epithelium. Some extra hypophyseal fibers go towards the epithalamus and the mesencephalon. To conclude, very early, in the human fetus the peptidergic LH-RH system resembles that described in adult primates; its role in the maturation and control of the gonadotropic cells is evoked.     

Adaptive changes in the nigrostriatal pathway in response to increased 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurodegeneration in the mouse

Although several adaptive mechanisms have been identified that mask the existence of Parkinson's disease and delay the onset and aggravation of motor symptoms, the timescale and implications of this compensatory process remain an enigma. In order to examine: (i) the nature of the dopaminergic adaptive mechanisms that come into action; (ii) their sequential activation in relation to the severity of degeneration; and (iii) their efficacy with regard to the maintenance of a normal level of basal ganglia activity, we analysed the brains of mice treated daily with 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP, 4 mg/kg, i.p.) and killed at 5-day intervals from day 0 (D0) to D20. Our results demonstrate the sequential activation of two compensatory mechanisms: (i) an increase in striatal tyrosine hydroxylase (TH) protein content attested by the persistence of TH immunolabelling up to D15, contrasting with the decrease observed in both the number of nigral TH-immunoreactive neurons (-70.2%) and striatal dopamine content (-38.4%); (ii) a downregulation of DA uptake in surviving terminals at D20 (73.4% of nigral degeneration). At this point, the failure of adaptive mechanisms to maintain striatal dopaminergic homeostasis is also illustrated by an increase in the cytochrome oxidase activity of substantia nigra pars reticulata, a marker of neuronal function. It has been postulated that an increase in dopamine release per pulse could constitute an adaptive mechanism. The data we present from our MPTP mice model infirm this hypothesis. This study explores the link between the degree of nigral degeneration and the sequential activation of dopaminergic compensatory mechanisms in the nigrostriatal pathway and, in so doing, proposes a rethink of the paradigm applied to these mechanisms.     

Renal vascular disease: medical management, angioplasty, and stenting

In the absence of large, prospective, quality randomized trials, there remains tremendous debate concerning the optimal management of patients with renal vascular disease. This debate is compounded by the fact these patients do not represent a homogeneous group; different causes and presentations each carry a different prognosis and potential response to therapy. Therapeutic options include medical management, surgery, or percutaneous approaches (angioplasty or stenting). This review examines the results of observational studies of medical and percutaneous therapies for blood pressure control and preservation of renal function. Generally, in patients with fibromuscular disease, the results of percutaneous management are superior to medical therapy. Although these observational studies are difficult to compare, in patients with atheromatous disease, the results with interventional and medical therapy appear roughly similar. There have been three randomized prospective trials of routine angioplasty versus medical management. These trials show little advantage to interventional therapies in those patients whose blood pressure is well controlled with medication who do not show progression of renal insufficiency during medical management. Based on these data, this review outlines a potential management strategy that relies on an individualized risk benefit assessment.     

In vitro expression of inducible nitric oxide synthase in the nasal mucosa of guinea pigs after incubation with lipopolysaccharides or cytokines

In order to demonstrate the involvement of nitric oxide synthases (NOS) – in particular the inducible isoform (iNOS) – in inflammatory processes within the nasal airways, we used organ-bath incubation to study isolated inferior turbinates and mucosa of the maxillary sinus of guinea pigs. The pattern of the expression in various substructures of the nasal mucosa was of special interest. Mucosa was incubated for 6 h with lipopolysaccharides (LPS) produced by E. coli, interleukin II (IL-2) or tumor necrosis factor-alpha (TNF-α). Saline was used as the control solution. Following incubation the specimens were fixed in buffered 4% formaldehyde solution over a period of 4 h. Tissues were next exposed to nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase-reaction and immunostained with specific antibodies to iNOS. Results then showed a clearly increased or initiated expression of iNOS in epithelium, glands, leucocytes and blood vessels of treated tissues in comparison to the control specimens. The inflammatory mediator LPS and the cytokines Il-2 or TNF-α alone were found to be capable of increasing the expression of iNOS, although the effects of LPS clearly exceeded those of the cytokines. This finding implicates iNOS-generated nitric oxide as a key factor for causing nasal swelling, secretion and obstruction during nasal infections and allergic episodes. Received: 18 November 1997 / Accepted: 22 April 1998     

Cardiovascular abnormalities in thoracopagus twins: embryological interpretation and review

The cardiovascular abnormalities of two sets of thoracopagus twins with conjoined heart and liver are described and compared with 27 well documented cases. An embryological interpretation of the cardiovascular abnormalities is suggested. The common heart in both sets showed a common atrium and two ventricles. In case 1 the great arteries were L. malposed in twin A. In case 2 the great arteries originated from their respective double outlet single ventricle. The systemic and pulmonary veins drained directly into the common atrium in case 1 and indirectly via systemic veins in case 2. The type of cardiovascular abnormalities are complex and discordent from one set to another and in the same set. However among 27 published cases of thoracopagus twins, cardiac union, including atrial union with separate ventricles, or atrial and ventricular union, was encountered in 16 cases. Approximately 90% of them are not suitable for surgical separation because of the high degree of cardiac union and the complexity of cardiovascular abnormalities. Surgical separation could be attempted in only two cases, but at the cost of the life of one of the twins.     

Einzelreferate und Buchbesprechungen

Ohne Zusammenfassung     

Versuche einer chemischen Charakterisierung und Reindarstellung des Trichophytins (des aktiven,antigenen Prinzips pathogener Hautpilze)

Ohne Zusammenfassung