[Hormone evaluation in brain death].

Background: In this study, the level and the variation of a number of hormone and metabolic parameters during brain death treatment in potential organ donors have been monitored.

Methods: Thirty-nine consecutive brain-dead patients were enrolled in 3 Intensive Care Units of Regional Hospitals of the North of Italy. All patients were potential organ donors and free from diseases before the accident leading to death.

Ethylene-oxide and steam-sterilised polysulfone membrane in dialysis patients with eosinophilia.

Eosinophilia and some acute dialysis side-effects, such as itching, flushing and bronchospasm, are often associated with the presence of ethylene oxide (ETO) as dialyzer sterilizing agent. This study evaluated the effects of two different polysulfone (PS) hollow-fiber dialysers sterilized with ETO and steam in 31 chronic dialysis patients with eosinophilia. Clinical symptoms, metabolic and biochemical parameters, complement (C3a and C5a) activation and production were evaluated in each patient dialysed for two months at a time with Cuprophan dialyser, ETO-PS dialyser and steam-PS dialyser.

The pleurodele, an animal model for space biology studies.

Pleurodeles waltl, an Urodele amphibian is proposed as a model for space biology studies. Our laboratory is developing three types of experiments in space using this animal: 1) in vivo fertilization and development ("FERTILE" project); 2) influence of microgravity and space radiation on the organization and preservation of specialized structures in the neurons and muscle cells (in vitro; "CELIMENE" PROJECT); 3) influence of microgravity on tissue regeneration (muscle, bone, epidermis and spinal cord).

Multicentre evaluation of the Serono SR1 assay for prostate specific antigen.

This report describes the findings of an evaluation of the validity of the new, highly automated Serono SR1 enzyme immunoassay for prostate specific antigen performed at three European sites. Within-run precision was below 5.5% at the clinically important decision point of 4 micrograms/l, less than 10% below 3 micrograms/l and less than 5% above 4 micrograms/l.

Hyponatremic hypertensive syndrome and massive proteinuria in a patient with renin-producing leiomyosarcoma.

We report a case of renin-producing leiomyosarcoma associated with the hyponatremic hypertensive syndrome and nephrotic-range proteinuria. Extremely high levels of active renin and, to a greater extent, of prorenin were found in plasma and tumor tissue. Immunohistochemical and in situ hybridization studies demonstrated that the neoplastic cells were the source of renin production.

Urinary albumin excretion in normal pregnancy and pregnancy-induced hypertension.

We measured the urinary excretion of albumin in 67 healthy primigravidae, at monthly intervals, from 16 to 36 weeks of gestation and 12 weeks postpartum. Of the 67 primigravidae, 55 completed a normal pregnancy and 12 developed pregnancy-induced hypertension. In the latter group, an additional measurement of urinary albumin excretion was performed at 24 weeks postpartum.

From presumptive ectoderm to neural cells in an amphibian.

As an immediate consequence of neural induction during gastrulation, some neuroectodermal cells acquire the ability to develop a number of specific neuronal and astroglial features, without requiring subsequent chordamesodermal cues. Thus, cholinergic, dopaminergic, noradrenergic, gabaergic, somatostatinergic, enkephalinergic, etc. traits are expressed in cultures of neural plate and neural fold isolated from amphibian late gastrulae immediately after induction and cultured in a defined medium.

Cross-linking of membrane glycoconjugates is not a sufficient condition for neural induction by concanavalin A.

Tetravalent native concanavalin A (Con A) has a neural inducing effect on amphibian presumptive ectoderm. The divalent dimeric form of this lectin, succinylated Con A (Succ-Con A), is devoid of neuralizing action on this target tissue in Pleurodeles waltlii. These results suggested that cross-linking of Con A receptors on the cell membrane (which is not provoked by the divalent lectin) might be required for neural induction.

Alterations in lateral lipid mobility in the plasma membrane of urodelean ectodermal cells during gastrulation.

The mobility characteristics of lipids were studied in the plasmalemma of dissociated presumptive ectodermal cells from embryos of Pleurodeles Waltl at different stages of development, from early blastula to early neurula, using a Fluorescence Recovery After Photobleaching technique (FRAP), after incorporation of the lipophilic fluorescent probe 5N-(hexadecanoyl)-aminofluoresceine (HEDAF) into the cell plasma membrane. At all stages of development, fluorescence recovery was found to extrapolate to 100%, which suggested that the lipid phase in these plasma membranes can be regarded as dynamically homogeneous (no immobilized fraction). It appears as a continuum over a wide cell surface area, in which lipids are free to move laterally.

Structural alteration of the target plasma membrane affects reception but not expression of the neural inductive signal.

We have previously reported that incubation of presumptive neuroectoderm in a solution of lectin (soybean agglutinin or garden pea agglutinin at 50 micrograms ml-1, 30 min) prior to its association with blastoporal lip inhibits neural induction (Duprat et al., 1982). We have also shown that incubation of presumptive ectoderm immediately after its association with blastoporal lip does not prevent neural induction.

Effect of short-term cyclosporine administration in rats on renin-angiotensin and thromboxane A2: possible relevance to the reduction in glomerular filtration rate.

A short-term treatment with Cyclosporine A (CyA) induces a decrease in glomerular filtration rate (GFR), promptly reversible after withdrawal of the drug. Several lines of evidence are now available as to indicate that this phenomenon is dependent on a hemodynamic perturbation resulting in a renal vasoconstriction. With the present work we have examined the relationship between the reduction in GFR which follows a short-term administration of CyA in rats and the biochemical changes in renin-angiotensin system and renal arachidonic acid metabolism.

Neural induction.

The molecular mechanism of neural induction of embryonic cells is an important but poorly understood problem in neuroembryology. Glycoconjugates in the target cell plasma membrane and/or its structural organization play a key role in the reception of the inductive signal. It is the competent target tissue itself which probably contains the capacity and specificity for neuralization.

Neural induction and in vitro initial expression of neurofilament and tetanus toxin binding site molecules in amphibians.

Tetanus toxin (Tt) binding site and neurofilament (NIF), the intermediate-sized filaments, are neuronal markers essentially described in mammals and birds; are these molecular markers present in urodela neuronal cells and are they expressed immediately after neural induction? Our findings are based on immunofluorescent localization of NIF and Tt proteins using three previously characterized antisera against 200 kDa and 70 kDa neurofilament components and against fragment IIc derived from purified tetanus toxin. Embryonic undifferentiated neuronal cells from Pleurodeles waltlii neural plate and/or neural fold (early neurula stage) are cultured isolated in vitro without further chordamesodermal influence. At the beginning of the culture none of the undifferentiated neuronal precursors bind antibodies against NIF or Tt components.

Neural induction: embryonic determination elicits full expression of specific neuronal traits.

In Pleurodeles waltl, the early neuronal differentiation of precursor cells from late gastrula stage has been studied by culture in vitro from either isolated neural plate (NP) or isolated neural fold (NF). The aim of this study was to delineate the information acquired by ectodermal target cells during neural induction. By culturing these cells in vitro either with or without the underlying chordamesoderm, we showed that in the absence of chordamesodermal influence such NP or NF cells exhibited a high degree of biochemical and morphological differentiation as revealed by the synthesis and the storage of neurotransmitters, the activity of specific enzymes, as well as by the expression of neuronal markers: specific changes in cell surface carbohydrates, tetanus toxin binding sites and neurofilament polypeptides.

Extracellular matrix and neural determination during amphibian gastrulation.

Previous studies have shown the presence of a network of extracellular matrix on the inner surface of the ectoderm of the early gastrulae Pleurodeles waltlii. Similar dense networks have been described by other authors in another Urodele species and in Anurans. It now seems well established that this extracellular material (ECM) has important functions in the mechanisms of morphogenetic cell movements during gastrulation.

Membrane changes in neural target cells studied with fluorescent lectin probes.

The competent ectoderm of Pleurodeles waltl comprises two cell layers with characteristic differences in their morphology, their composition and the molecular arrangement of the various constituents. The use of labelled lectin probes for observations of ectoderm tissue in vitro with u.v.

Neural induction and the structure of the target cell surface.

Lectins (SBA and PSA) were used to provoke crowding and structural modifications of the presumptive ectoderm cell surface in order to investigate the role of the membrane organization of the competent target cells in neural induction. Are specific characteristics of the cell surface essential for this phenomenon to occur? From amphibian gastrulae, it is possible to obtain neural induction in vitro by association of presumptive ectoderm (target cells) with chordamesoderm (inductor tissue): 4 h of contact is sufficient in Pleurodeles waltl for transmission of the inductive signal. Very quickly, the treatment of the normal ectoderm by lectins (SBA-FITC or PSA-FITC) provoked surface modifications.

A rapid experimental method to study primary embryonic induction.

The technique described here is a combination of the sandwich-method and cell culture. It allows one to know quickly whether induction occurred or not (48 h if cell spreading is considered, 4-5 days if morphological differentiation is observed). The dissociation of the explants soon after induction does not disturb their inductive pattern.