Increase in SNAP-25 immunoreactivity in the mossy fibers following transient forebrain ischemia in the gerbil

SNAP-25 (a synaptosomal-associated protein of 25 kDa) has been shown to be involved both in synaptic vesicle exocytosis and in axonal outgrowth. In the present study, we investigated the changes in SNAP-25 immunoreactivity in the hippocampus of the Mongolian gerbil (Meriones unguiculatus) at different time points after transient forebrain ischemia insult. In parallel, immunostaining for GAP-43, a protein involved in axonal outgrowth, and for syntaxin-1 (stx1A and stx1B), another protein implicated in neurotransmitter release, was also analyzed. The animals were subjected to 2.5 or 5 min of transient forebrain ischemia through bilateral common carotid occlusion, and examined at different intervals after ischemia. SNAP-25 immunoreactivity was increased in the mossy fiber layer as early as 2 days after 5 min of ischemia. Increased SNAP-25 immunoreactivity in mossy fibers was also detected at days 4 and 7 after ischemia. On day 15, SNAP-25 staining was similar to that observed in control non-ischemic animals. In contrast, no changes in GAP-43 and syntaxin-1 immunoreactivity were observed in the mossy fiber layer following 5 min of ischemia. No modifications in SNAP-25, syntaxin-1 or GAP-43 immunoreactivity were observed following 2.5 min of ischemia, the longest period for which no neuronal damage is observed. These results provide evidence of a specific involvement of SNAP-25 in the reactive changes associated with transient forebrain ischemia.

Distribution of fibroblast growth factor receptor-1 (FGFR-1) and FGFR-3 in the hippocampus of patients with Alzheimer's disease

To learn about the localization of fibroblast growth factor (FGF) ligands in normal and pathologic brains, fibroblast growth factor receptor-1 (FGFR-1; Flg) and FGFR-3 immunoreactivities were examined in the hippocampus of patients with Alzheimer's disease and age-matched controls. Flg immunoreactivity was found in practically all neurons of the hippocampus and dentate gyrus in control and Alzheimer's disease cases. In patients with Alzheimer's disease, Flg immunoreactivity was present in tangle-bearing and non-tangle-bearing neurons, as well as in neurons with granulovacuolar degeneration, but not in ghost tangles. Aberrant neurites of senile plaques were negative. FGFR-3 immunoreactivity was found in reactive glial cells, most of them astrocytes, including those in the vicinity of senile plaques.

8-Azido-nucleotides as substrates of Torpedo electric organ apyrase. effect of photoactivation on apyrase activity

Ecto-apyrase is a widespread enzymatic activity that hydrolyses tri- and diphosphonucleotides and consequently controls the amount of available extracellular ATP and ADP. In the nervous system, purines have important neuromodulatory actions, acting at pre- and postsynaptic sites, and consequently, ecto-apyrase may play an indirect role in the modulation of nucleotide- and nucleoside-mediated processes. The azido-nucleotides have been largely employed to characterize the nucleotide binding sites of several proteins. In the present work the azido-nucleotides are described as putative substrates for apyrase activity in a presynaptic plasma membrane preparation (PSPM) from the Torpedo electric organ. Both 8-N3-ATP and 8-N3-ADP were hydrolyzed in a calcium-dependent manner showing Vmax of 23.8 +/- 4.8 and 14.5 +/- 3 U/mg of protein, and Km values (in microM) of 116 +/- 39 and 119 +/- 4, respectively. Vmax for calcium-dependent hydrolysis of ATP and ADP were significantly higher: 59.2 +/- 3.9 and 32.9 +/- 3.5 U/mg of protein respectively, while Km values did not show any significant differences regarding azido-nucleotides: 83.8 +/- 12 microM for Ca2+-ATP and 121 +/- 34 microM for Ca2+-ADP. The photoactivation of the PSPM in the presence of the azido-derivatives results in an irreversible inactivation of apyrase activity, showing an IC50 of 10 microM and a maximal inhibitory effect of 38 and 60% on Ca2+-ATPase and Ca2+-ADPase activities. Apyrase was protected from inactivation by nucleotides that are natural substrates for this enzymatic activity and also by AMP while adenosine did not protect from apyrase inhibition.

Vitronectin is expressed in the ventral region of the neural tube and promotes the differentiation of motor neurons

The extracellular matrix protein vitronectin and its mRNA are present in the embryonic chick notochord, floor plate and in the ventral neural tube at the time position of motor neuron generation. When added to cultures of neural tube explants of developmental stage 9, vitronectin promotes the generation of motor neurons in the absence of either notochord or exogenously added Sonic hedgehog. Conversely, the neutralisation of endogenous vitronectin with antibodies inhibits over 90% motor neuron differentiation in co-cultured neural tube/notochord explants, neural tube explants cultured in the presence of Sonic hedgehog, and in committed (stage 13) neural tube explants. Furthermore, treatment of embryos with anti-vitronectin antibodies results in a substantial and specific reduction in the number of motor neurons generated in vivo. These results demonstrate that vitronectin stimulates the differentiation of motor neurons in vitro and in vivo. Since the treatment of stage 9 neural tube explants with Sonic hedgehog resulted in induction of vitronectin mRNA expression before the expression of floor plate markers, we conclude that vitronectin may act either as a downstream effector in the signalling cascade induced by Sonic hedgehog, or as a synergistic factor that increases Shh-induced motor neuron differentiation.

Localization of putative receptors for tetanus toxin and botulinum neurotoxin type A in rat central nervous system

Clostridial neurotoxins (tetanus and botulinum toxins) are potent blockers of neurotransmitter release. These toxins act specifically on the nervous system by interacting with still non-identified protein receptors together with gangliosides. Whereas many biochemical data are available on their binding properties to neuronal membranes in vitro, there is poor morphological evidence of their binding to mammalian central nervous system. In the present study, the binding of tetanus and botulinum neurotoxin type A to rat brain sections is reported. Both toxins bound to nerve terminals with a broad distribution in brain. Tetanus toxin additionally bound to nerve fibres. The staining patterns were clearly shown to be due to the interaction of the heavy chains, which contain the binding moiety, with the tissue. In an attempt to investigate the nature of the acceptors present in the tissue, some sections were pre-incubated with periodic acid. This treatment resulted in the additional binding of botulinum neurotoxin type A to nerve fibres. Since the extended staining of nerve terminals was not modified by this pretreatment, it is suggested that protein receptors of clostridial neurotoxins are located at the nerve terminals, which may be common constituents of the synapses.

BDNF and TrkB co-localize in CA1 neurons resistant to transient forebrain ischemia in the adult gerbil

Delayed cell death of projection cells in the CA1 area of the hippocampus is produced in the adult gerbil following 5 minutes (min) of transient forebrain ischemia. Parvalbumin-immunoreactive local-circuit neurons are resistant to the ischemic insult. Brain-Derived Neurotrophic Factor (BDNF) immunoreactivity is localized in all neurons of the CA1 area in control gerbils. However, TrkB immunoreactivity is observed in a minority of BDNF-immunoreactive neurons in the CA1 area. The number of BDNF-immunoreactive cells in CA1 is dramatically reduced in ischemic gerbils as early as 24 h after ischemia, but the number of TrkB-immunoreactive cells in the CA1 area is maintained following ischemia. Moreover, about 90% of BDNF-immunoreactive cells and about 85% of TrkB-immunoreactive cells in ischemic gerbils co-localize the calcium-binding protein parvalbumin. Finally, BDNF and TrkB are coexpressed in about 95% of CA1 neurons surviving the ischemic insult. These results indicate that a subpopulation of CA1 hippocampal neurons coexpressing TrkB, parvalbumin and BDNF is resistant to transient forebrain ischemia in the gerbil. These results also suggest that a subpopulation of CA1 hippocampal neurons in the gerbil hippocampus is endowed with a putative BDNF/TrkB autocrine regulatory loop that may be involved in both cell survival and synaptic remodeling of the damaged gerbil hippocampus following transient forebrain ischemia.

[Identification of 5 variants of the hemoglobin beta chain using DNA analysis (amplification, sequencing and restriction enzymes)]

PURPOSE

To confirm the conventional techniques for studying structural haemoglobinopathies and to show off the simplicity and efficacy of new methods based on the study of DNA.

PATIENTS AND METHODS

Peripheral blood samples of 17 patients with 5 haemoglobin variants detected by conventional and shown off by means of sequencing according to Sanger's method, plus PCR-RFLP, were studied.

RESULTS

Five structural haemoglobin variants were found, which distributed as follows: 7 cases of Hb Complutense (beta 127 Gln-->Glu), 1 Hb D-Punjab (beta 121 Glu-->Gln), 3 Hb Hofu (beta 126 Val-->Glu), 3 Hb J-Baltimore (beta 16 Gly-->Asp) and 3 Hb San Diego (beta 109 Val-->Met).

CONCLUSIONS

These results allow us to stress the simplicity and usefulness of DNA analysis (sequencing , amplification and enzymatic digestion) to identify haemoglobin variants as opposed to laborious analysis of the primary structure by means of HPLC peptide separation.

[The association of beta zero-thalassemia and Hb D Punjab in a family of Indian origin. The second case reported in Spain]

The present report described the hematologic and molecular study of the second case of Hb D-Punjab associated with a beta zero-thalassemia found in Spain and the first case in which the mutations have been identified at molecular level. A family from India is studied, which is constituted by mother (I2) and 3 children (II1, II2 and II3). The molecular characterization of the hemoglobinopathy was made by electrophoretic and chromatographic techniques and confirmed by sequencing of the beta-globin gene. The mutation causer of the beta-thalassemia was studied by PCR-ARMS. The mother (I2) and one of her child (II2) are carriers of the gene for beta zero-thalassemia owing to the frameshift CD 8/9 mutation (+ G). Other of them (II1) is heterozygous for Hb D-Punjab without beta-thalassemia association. The third child (II3) knows a double heterozygote state for Hb D-Punjab/beta zero-thalassemia (hemoglobin D-thalassemia). In spite of the patient with hemoglobin D-thalassemia has 94.5% of Hb D, without Hb A, the hematologic picture belongs to thalassemia trait with moderate haemolytic anemia, intense microcytosis and hypochromia and numerous target cells. This hematologic picture discloses the mildness of the Hb D-Punjab, but the reliable responsible for the phenotype is the disbalance in the synthesis of globin chains, because of frameshift CD 8/9 mutation (+ G) beta zero-thalassemia mutation.

The metabolic productivity of the cell factory

It is widely accepted that some performance function has been optimized during the evolution of metabolic pathways. One can study the nature of such a function by analogy with the industrial manufacturing world, in which there have been efforts over recent decades to optimize production chains, and in which it is now accepted that fluxes are not the only important system variables that determine process efficiency, because inventory turnover must also be considered. Inspired by the parallels between living cells and manufacturing factories, we propose that fluxes and transit time may have simultaneously been major targets of natural selection in the optimization of the design, structure and kinetic parameters of metabolic pathways. Accordingly we define the ratio of flux to transit time as a performance index of productivity in metabolic systems: it measures the efficiency with which stocks are administered, and facilitates comparison of a pathway in different steady states or in different tissues or organisms. For a linear chain of two enzymes, at a fixed total equilibrium constant, we have analysed the variation of flux, transit time and productivity index as functions of the equilibrium constants of the two steps. The results show that only the productivity index has a maximum, which represents a good compromise in optimizing flux and transit time. We have extended control analysis to the productivity index and derived the summation theorem that applies to it. For linear chains of different length with maximum productivity index values, the distribution of control coefficients with regard to the three parameters has a characteristic profile independent of the length of the chain. Finally, this control profile changes when other variables are optimized, and we compare the theoretical results with the control profile of the first steps of glycolysis in rat liver.

Insulin-like growth factor-I stimulates neurogenesis in chick retina by regulating expression of the alpha 6 integrin subunit

Insulin-like growth factor I (IGF-I) strongly stimulates the generation of differentiated neurons in cultures of neuroepithelial cells of the embryonic chick neural retina in the presence of a laminin-1 tissue culture substrate. Treatment of cultured neuroepithelial cells with IGF-I rapidly up-regulated the mRNA coding for the alpha 6 integrin subunit whereas specific reduction of alpha 6 subunit levels by treatment with an alpha 6 integrin antisense oligonucleotide resulted in reduced neuronal differentiation in vitro. Although IGF-I immunoreactivity is seen throughout the neural retina, expression of IGF-I mRNA is confined to the pigment epithelium during the period of neurogenesis in vivo. Neutralization of the endogenous IGF-I with a blocking antibody down-regulated levels of alpha 6 integrin mRNA and reduced the production of differentiated retinal neurons in vivo. These data indicate a role for IGF-I in the generation of retinal neurons mediated by the interaction of laminin with its alpha 6 integrin subunit-containing receptor.

Neurotrophin-3 antibodies disrupt the normal development of the chick retina

When chick embryos are treated with a monoclonal antibody specifically blocking the activity of neurotrophin-3 (NT-3), the development of the retina is profoundly affected. Fewer axons are found in the optic nerve, and the retina shows abnormalities in all layers. Early during retinogenesis, the proportion of dividing cells is higher in NT-3-deprived embryos compared with age-matched controls and that of differentiated neurons is smaller. The NT-3 receptor trkC is expressed early by a majority of retinal cells, and NT-3 is present in the retina at the earliest stage studied. Initially, it is located mainly in the pigmented epithelium, with a shift toward the neural retina as development proceeds. Thus, NT-3 seems to be an essential intrinsic signal acting early in development to promote the differentiation and survival of many retinal neurons.

Action of suramin upon ecto-apyrase activity and synaptic depression of Torpedo electric organ

1. The role of ATP, which is co-released with acetylcholine in synaptic contacts of Torpedo electric organ, was investigated by use of suramin. Suramin [8-(3-benzamido-4-methylbenzamido)naphthalene-1,3,5-trisulphoni c acid], a P2 purinoceptor antagonist, potently inhibited in a non-competitive manner the ecto-apyrase activity associated with plasma membrane isolated from cholinergic nerve terminals of Torpedo electric organ. The Ki was 30 microM and 43 microM for Ca(2+)-ADPase and Ca(2+)-ATPase respectively. 2. In Torpedo electric organ, repetitive stimulation decreased the evoked synaptic current by 51%. However, when fragments of electric organ were incubated with suramin the evoked synaptic current declined by only 14%. Fragments incubated with the selective A1 purinoceptor antagonist, DPCPX, showed 5% synaptic depression. 3. The effects of suramin and DPCPX on synaptic depression were not addictive. Synaptic depression may thus be linked to endogenous adenosine formed by dephosphorylation of released ATP by an ecto-apyrase. The final effector in synaptic depression, adenosine, acts via the A1 purinoceptor. 4. ATP hydrolysis is prevented in the presence of suramin. It slightly increased (20%) the mean amplitude of spontaneous miniature endplate currents. The frequency distribution of the amplitude of spontaneous events was shifted to the right, indicating that ATP, when not degraded, may modulate the activation of nicotinic acetylcholine receptors activated by the quantal secretion of acetycholine.

Inhibition of ATP-diphosphohydrolase(apyrase) of Torpedo electric organ by 5'-p-fluorosulfonylbenzoyladenosine

It has been shown previously that ATP is released into extracellular space from pre- and postsynaptic sources in peripheral synapses. The extracellular metabolism of ATP is likely to affect nucleotide- and nucleoside-mediated regulation of neurotransmission. The enzymes responsible for ATP breakdown are nucleotidases whose active site faces the extracellular space. ATPase and ADPase Ca(2+)-dependent activities were characterized in presynaptic plasma membrane preparation from the electric organ of Torpedo. Features described were in accordance with the presence of an ATP-diphosphohydrolase (apyrase EC 3.6.1.5) in this fraction. Active site studies using the affinity label 5'-fluorosulfonylbenzoyladenosine were performed on Torpedo apyrase. ATPase and ADPase Ca(2+)-dependent activities were inhibited with 5'-fluorosulfonylbenzoyladenosine. From this study it is concluded: (1) 5'-fluorosulfonylbenzoyladenosine binds specifically to the active site of apyrase. (2) Divalent cations accelerate the apyrase inactivation rate. (3) Divalent cations are not required for the binding of either the substrate or the inhibitor to the active site. (4) The apyrase active site is more specific for highly phosphorylated nucleotides. The results presented may be extrapolated to apyrases from other sources. The importance of this enzyme and its regulation are discussed.

Relationship of curative surgery on natural killer cell activity in colorectal cancer

PURPOSE

Aim of this study has been to evaluate natural killer (NK) activity in patients with colorectal tumors before and after curative surgery.

METHODS

Forty colorectal cancer patients without distant metastases were stratified according to American Joint Committee on Cancer/International Union Against Cancer staging system into three categories: Stage I (n = 12), Stage II (n = 15), and Stage III (n = 13). All of them underwent curative resection, and there were no major postoperative complications. Venous blood samples were obtained preoperatively, at surgical wound closure, and on the 1st, 7th, and 21st postoperative days. Mononuclear cells were isolated over Ficoll-Hypaque (Lymphoprep, Nycomed Pharma AS, Oslo, Norway) gradients, and NK activity was assayed by evaluation of cytotoxic response against K562 cells. Normal NK activity was achieved from 15 healthy donors. Percentage relative increments in relation to preoperative levels were calculated for every postoperative sample, and t-test was used for statistical evaluation.

RESULTS

Before surgery, Stages II and III patients had lower levels of NK activity than healthy people (P < 0.05 and P < 0.001, respectively). NK activity always fell after surgery (Stage I: -18.48 +/- 11.42; Stage II: -16.93 +/- 13.57; Stage III: -35.29 +/- 12.03, at day 1 postsurgery) and appeared to rise slightly by the 21st postoperative day in Stage I patients (+4.87 +/- 12.41). Stage II, and especially Stage III, patients did show a significant recovery by the 21st postoperative day (+23.63 +/- 9.36 and +43.19 +/- 13.34, respectively). At this time, NK activity in these two groups was not significantly lower than in normal subjects (P > 0.05).

CONCLUSION

NK activity is depressed in colorectal cancer patients in relation to progression of illness, even at locoregional stages. Curative resection of tumors at Stages II and III has promoted a recovery of NK activity in patients with uneventful postoperative courses.

Developmentally regulated vitronectin influences cell differentiation, neuron survival and process outgrowth in the developing chicken retina

Vitronectin is a multifunctional protein involved in the regulation of the immune system and blood coagulation. Here we report that the expression of vitronectin is developmentally regulated in the embryonic retina of the chicken. Vitronectin immunoreactivity was detected in chicken retinas from embryonic day 5, encompassing the cell bodies of most neuroepithelial cells. At this developmental stage, alpha v integrin subunit expression was distributed across the retina, suggesting a ligand/receptor interaction. Expression of both vitronectin and alpha v increased during development and reached a maximum at embryonic day 9, a time when most differentiated neurons grow processes and initiate synapse formation. At this age, vitronectin immunoreactivity appeared to be located predominantly in the fiber and inner plexiform layers of the differentiated stratified retina. alpha v immunoreactivity and mRNA expression was seen associated with all layers formed by differentiated neurons, being most abundant in the ganglion cell and inner nuclear layers. Later in development, levels of vitronectin decreased and immunoreactivity appeared exclusively associated with the fiber layer. In accordance with this pattern of expression, vitronectin as a substrate sustained both proliferation and differentiation of cultured neuroepithelial cells from embryonic day 5 retinas. At later stages, vitronectin supported survival and neurite outgrowth of most differentiated neurons. Our data suggest that vitronectin is a ubiquitous component of the retinal extracellular matrix, serving as a substrate for developmental processes such as proliferation, differentiation of neuron progenitors, cell survival, and axonal and dendritic growth of differentiated neurons.

The effect of intravenous lipids on gastric emptying in rats subjected to total parenteral nutrition

Total parenteral nutrition (TPN) is indicated in a number of clinical situations involving obstructive disorders of the gastrointestinal tract or when total bowel rest is required. However, little is known of its effects upon the physiology of gastric storage and emptying. A study of the effects of lipid nutrient content of TPN on the gastric emptying of a non-energy liquid test meal in male and female conscious rats (250-280 g) was undertaken. Five experimental groups were set up according to the percentage of total non-protein energy administered in the form of different lipids: A (lipid-free: 100% of non-protein energy as glucose); B (5% long-chain triglycerides (LCT), 95% glucose); C (40% LCT, 60% glucose); D (5% LCT and medium-chain triglycerides (MCT) in 1:1 proportion, 95% glucose); and E (40% LCT and medium-chain triglycerides (MCT) in 1:1 proportion, 60% glucose). Animals were maintained on TPN for 24 h and for 3 and 4 days, after which gastric emptying was measured by the phenol red method. 40% lipid TPN was found to accelerate gastric emptying as infusion was prolonged, although the type of lipid had no effect.

Distribution of Sonic hedgehog peptides in the developing chick and mouse embryo

Sonic hedgehog (Shh) encodes a signal that is implicated in both short- and long-range interactions that pattern the vertebrate central nervous system (CNS), somite and limb. Studies in vitro indicate that Shh protein undergoes an internal cleavage to generate two secreted peptides. We have investigated the distribution of Shh peptides with respect to these patterning events using peptide-specific antibodies. Immunostaining of chick and mouse embryos indicates that Shh peptides are expressed in the notochord, floor plate and posterior mesenchyme of the limb at the appropriate times for their postulated patterning functions. The amino peptide that is implicated in intercellular signaling is secreted but remains tightly associated with expressing cells. The distribution of peptides in the ventral CNS is polarized with the highest levels of protein accumulating towards the luminal surface. Interestingly, Shh expression extends beyond the floor plate, into ventrolateral regions from which some motor neuron precursors are emerging. In the limb bud, peptides are restricted to a small region of posterior-distal mesenchyme in close association with the apical ectodermal ridge; a region that extends 50–75 microns along the anterior-posterior axis. Temporal expression of Shh peptides is consistent with induction of sclerotome in somites and floor plate and motor neurons in the CNS, as well as the regulation of anterior-posterior polarity in the limb. However, we can find no direct evidence for long-range diffusion of the 19 × 10(3) Mr peptide which is thought to mediate both short- and long-range cell interactions. Thus, either long-range signaling is mediated indirectly by the activation of other signals, or alternatively the low levels of diffusing peptide are undetectable using available techniques.

Requirement of 19K form of Sonic hedgehog for induction of distinct ventral cell types in CNS explants

The identity and patterning of ventral cell types in the vertebrate central nervous system depends on cell interactions. For example, induction of a specialized population of ventral midline cells, the floor plate, appears to require contact-mediated signalling by the underlying notochord, whereas diffusible signals from the notochord and floor plate can induce ventrolaterally positioned motor neurons. Sonic hedgehog (Shh), a vertebrate hedgehog-family member, is processed to generate two peptides (M(r) 19K and 26/27K) which are secreted by both of these organizing centres. Moreover, experiments in a variety of vertebrate embryos, and in neural explants in vitro, indicate that Shh can mediate floor-plate induction. Here we have applied recombinant Shh peptides to neural explants in serum-free conditions. High concentrations of Shh bound to a matrix induce floor plate and motor neurons, and addition of Shh to the medium leads to dose-dependent induction of motor neurons. All inducing activity resides in a highly conserved amino-terminal peptide (M(r) 19K). Moreover, antibodies that specifically recognize this peptide block induction of motor neurons by the notochord. We propose that Shh acts as a morphogen to induce distinct ventral cell types in the vertebrate central nervous system.

Tacrine-induced increase in the release of spontaneous high quantal content events in Torpedo electric organ

1. The anticholinesterases, tacrine (100 microM) and physostigmine (60 microM) had different effects on the amplitude distribution and kinetics of miniature endplate currents (m.e.p.cs) recorded extracellularly from the electric organ of Torpedo marmorata. 2. Tacrine increased the ratio of giant miniatures (larger than 4 mV of amplitude) to more than 20% of recorded spontaneous events. In the presence of physostigmine such events represented only 4%. 3. Both tacrine and physostigmine increased the rise time and the decay phase of normal-sized m.e.p.cs when compared to control conditions. Both effects were significantly greater for tacrine. 4. We have tested the specificity of the tacrine effect on ectoenzyme activities associated with plasma membranes of these pure cholinergic nerve endings. Tacrine does not act unspecifically on every ectoenzyme, because it is not able to block the ectoapyrase activity even at a concentration 100 fold greater than that required to inhibit 94% of AChE. 5. We conclude that the differential effects of tacrine and physostigmine can be explained in terms of undetermined presynaptic actions of tacrine, while comparable effects of the two compounds can be explained through a shared anticholinesterase activity.

Expression of the beta-subunit isoforms of the Na,K-ATPase in rat embryo tissues, inner ear and choroid plexus

We report evidence of the apical localization of the two Na,K-ATPase beta-subunit isoforms in cells of the inner ear and of the choroid plexus of the rat. To this end, we generated isoform-specific antisera against the human Na,K-ATPase beta 1 and beta 2 subunits. These polyclonal rabbit antisera were raised against truncated beta-isoform proteins that were made in E coli with pET expression vectors. Deglycosylation of the native antigen with N-endoglycosidase F shows four bands in the beta 1 isoform and five bands in the beta 2 isoform immunoblots. In E15 rat embryos, the beta 1 isoform was detected in brain, heart and kidney and the beta 2 isoform only in brain. While beta-subunit mRNA expression (Watts AG, Sanchez-Watts G, Emanuel JR, Levenson R (1991) Proc Natl Acad Sci USA 88, 7425-7429), immunoblotting and enzymatic activity have been determined (Zlokovic BV< mackic JB, Wang L, McComb JG, McDonough A (1993) J Biol Chem 268, 8019-8025), very little is known about the specific localization of each beta-isoform in the epithelia of choroid plexus and inner ear. Immunocytochemical preparations of 15-day-old whole rat embryos and adult rat brain showed an enhanced staining for the beta 1 and beta 2 isoforms in the apical membrane of the ampullary crests of the inner ear's semicircular ducts and in the cuboidal cells of the choroid plexus.

A four-layered 'lissencephalic' cortex induced by prenatal X-irradiation in the rat

A four-layered cortex is produced in the dorsal region of the rat brain, after 200 cGy X-irradiation at embryonic day 16. The layer 1 is the molecular layer; layer 2 is the upper cellular layer which is in continuity with normal layers V and VI in the lateral cortex; layer 3 is a sparsely cellular layer; and layer 4 is the inner cellular layer which is composed of neurons normally committed to the upper cortical layers. This failure of neuroblast migration to the upper layers is associated with reduced numbers, and morphological abnormalities, of radial glial cells in the dorsal cortex. This further supports the idea that abnormal interactions between neuroblasts and radial glial cells result in abnormal migratory patterns. Since a similar four-layered organization is found in human lissencephaly type I, the present results bring new data that can serve our better understanding of human cortical malformations.

A transient immunoglobulin-like reactivity in the developing cerebral cortex of rodents

Species-specific antisera against rat or mouse immunoglobulins, such as the commercial ones currently used as secondary antibodies in immunohistochemistry, revealed an intense, developmentally regulated immunostaining of the cerebral cortex in the homospecific rodent species. The immunostaining showed evident anatomical restrictions, favouring the subplate in prenatal animals. In Western blots, the antisera recognized the protein moiety of a 93 kDa glycoprotein. Both tissue and Western blot immunostaining were completely prevented by preadsorption of the antisera with the corresponding homospecific immunoglobulin. The present results show that a novel molecule, related to immunoglobulins, is transiently expressed in the developing cerebral cortex of rodents, and stress the need for exquisite controls in immunohistochemical studies.

Distribution of neuropeptide Y-like immunoreactivity in the brain of the lizard Gallotia galloti

The distribution of neuropeptide Y (NPY)-like immunoreactivity was studied in the brain of the lizard Gallotia galloti, in order to gain insight into the comparative topography of this peptide. Antisera against both NPY and its C-terminal flanking peptide (C-PON) were used, demonstrating a general coexistence of both peptides, as described in other vertebrates. Most NPY-like immunoreactive (NPY-LI) cell bodies were observed in the telencephalon, specifically in various olfactory structures, all cortices, septum, basal ganglia (except for the globus pallidus), the nucleus of the diagonal band of Broca, the amygdaloid complex, and the bed nucleus of the anterior commissure. NPY-LI cells were also seen in the preoptic and hypothalamic regions and the dorsal thalamus (mainly in the perirotundal belt), as well as in the mesencephalic tegmentum (in the ventral tegmental area, the substantia nigra, and the retrorubral area). NPY-LI fibers and terminals were widely distributed in the brain. All visual and auditory neuropiles were densely innervated. Specially dense plexuses were seen in the nucleus accumbens, the ventral pallidum, the suprachiasmatic and ventromedial hypothalamic nuclei, the nucleus medialis thalami, the left habenula, and the central nucleus of the torus semicircularis. Our analysis shows that the distribution of NPY-like immunoreactivity in the forebrain of Gallotia largely resembles that of other vertebrates, whereas differences are mainly observed in the brainstem. The widespread distribution of NPY in the lizard brain suggests several modulatory functional roles, either in local-circuit systems of the forebrain, or in various limbic, neuroendocrine, and sensory pathways.

Neuropeptide Y m-RNA and peptide are transiently expressed in the developing rat spinal cord

The distribution of neuropeptide Y (NPY) m-RNA and peptide were studied during the ontogeny of the rat spinal cord, by means of in situ hybridization and immunohistochemistry. NPY expressing neurons were visualized by both techniques, although by in situ hybridization they appeared slightly more abundant than by immunohistochemistry. In the ventral horn, a few neurons transiently expressed NPY from the embryonic day 15 to birth, but not in the adult animals. In the embryonic dorsal horn, NPY expressing neurons were numerous and seen as early as embryonic day 15 (E15). In contrast, in the postnatal and the adult dorsal horn, the number of neurons expressing the NPY phenotype was dramatically lower.

Carnosine, nerve growth factor receptor and tyrosine hydroxylase expression during the ontogeny of the rat olfactory system

The localizations of carnosine, nerve growth factor (NGF) receptor and tyrosine hydroxylase (TH) were studied in the embryonic and postnatal rat olfactory bulb and epithelium by means of single- and double-immunostaining methods. Tyrosine hydroxylase ontogeny was also evaluated at the mRNA level by in situ hybridization. All these molecules were expressed in the olfactory bulb but with different developmental patterns and cellular localization: carnosine immunoreactivity is seen from embryonic day 17 in primary olfactory neurons scattered in the nasal cavity and in fibres projecting from them to the olfactory bulb. Nerve growth factor-receptor immunoreactivity associated with small glial-like cells is visible in some glomeruli starting from the second day of postnatal life. At postnatal day 10 NGF-receptor immunoreactivity is extended to all glomeruli. Periglomerular neurons expressing TH mRNA and protein are present prenatally and their number sharply increases during the early postnatal development. Double-staining methods show that TH and NGF-receptor immunoreactivity do not overlap in cell bodies and processes. In addition, NGF-receptor immunoreactivity is not colocalized with carnosine. These findings definitely exclude NGF-receptor expression in periglomerular and primary olfactory neurons, suggesting that at least part of NGF-receptor expression in the olfactory bulb is associated with glial cells. In addition, they provide the first immunohistochemical data on carnosine ontogeny and confirm at the mRNA level previous studies on the ontogeny of TH protein.

Naturally occurring, postnatal cell death in the cerebral cortex of the micrencephalic rat induced by prenatal X-irradiation

Naturally occurring postnatal cell death in the somatosensory cortex and medial cortical areas was examined in micrencephalic rats produced after exposure to 100 cGy X-rays at embryonic day 15. The absolute numbers of dead cells per tissue section were not affected in the future subcortical white matter, but were severely decreased in the cerebral cortex when compared with age-matched controls. Furthermore, the proportion of cortical dead cells per 1000 live neurons in the cerebral cortex and the cumulative cell death across time were significantly reduced in irradiated animals. These results suggest that naturally occurring postnatal cell death in the cerebral cortex is reduced in micrencephaly.

Development of dendritic spines in the cerebral cortex of the micrencephalic rat following prenatal X-irradiation

Postnatal development of dendritic spines (DS) on the 500-microns-proximal region of the apical dendrite of large layer V pyramidal neurons of the somatosensory cortex (Par 1) was studied with the rapid Golgi method in micrencephalic rats produced after exposure to 100 cGy X-irradiation at embryonic day 18. Treated rats examined at the age of 15 days had more DS than age-matched controls, whereas the reverse occurred in rats aged 30 days. After this time the number of DS decreased in normal rats. As a result, irradiated and control rats aged 90 days had about the same number of DS in the proximal region of the apical dendrite. These results suggest that development of DS appears early, and that natural overproduction and elimination of DS is impaired in the cerebral cortex of micrencephalic rats.

Arteriolosclerotic leucoencephalopathy in the elderly and its relation to white matter lesions in Binswanger's disease, multi-infarct encephalopathy and Alzheimer's disease

Arteriolosclerotic leucoencephalopathy in the elderly (ALE) is characterized by white matter lesions associated with atherosclerosis and arteriolosclerosis. Mild lesions are focal and probably represent early status cribosus or incomplete lacunar infarcts. Moderate and severe lesions are diffuse areas of demyelination in the centrum semiovale in which lacunar infarcts are seldom observed. The incidence of ALE in a consecutive necropsy series of 50 cases (mean age 62.6 +/- 13.1 years) was 52%, it was rare in the fourth and fifth decades but increased thereafter to reach a prevalence of 100% at the age of 80 years. Mild lesions occurred in 19 patients and lesions were moderate or severe in 7 (14%). The mean age was higher in this group (74.7 +/- 7.6 years) than in patients with white matter changes as a whole. Dementia occurred only in 3 patients with moderate or severe ALE. These data suggest that (a) ALE is common in old age and is probably the cause of leuko-araiosis in most CT scans in the elderly; (b) ALE may be asymptomatic; (c) the severity of white matter changes may be not related to the severity of neurological deficits; and (d) multiple lacunar infarcts or associated degenerative diseases (i.e., Alzheimer's disease) may be the main cause of dementia in patients with ALE. White matter lesions in ALE, Binswanger's disease, transition areas in multi-infarct encephalopathy (MIE) and Alzheimer's disease (AD) are similar in morphology and are probably the result of a subacute hypoperfusion/hypoxic process. Increased arterial blood pressure is a frequent risk factor in ALE, Binswanger's disease and MIE, whereas congophilic angiopathy of the meningeal and cortical vessels, in addition to mild or moderate arteriolar hyalinosis in the white matter, may play a role in the pathogenesis of incomplete infarctation of the white matter in patients with AD.

Studies with the Golgi method in central gangliogliomas and dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease)

The rapid Golgi method, combined with current optical and electronmicroscopical techniques, was used in three central gangliogliomas and in one dysplastic gangliocytoma of the cerebellum to study the morphology of ganglionic cells. Gangliogliomas were composed of bipolar, fusiform and radiate cells with dense core and clear vesicles in the perikaryon and cellular processes, the number of each cellular type varying from one case to another. These features, together with the fact that isodendritic neurons are considered to be phylogenetically old neurons, suggest that these tumours are composed of "primitive" neurons that are not homogeneous with regard to their morphology. In contrast, ganglionic cells in dysplastic gangliocytoma are huge cells with long, stereotyped neurites that establish unique asymmetric contacts with neighbouring perikarya and neurites by means of claw-shaped processes covered with synaptic buttons. These morphological characteristics are different from those of any other neuron of the CNS.

[Myxoglobulosis of the cecal appendix]

We report a case of mucinous cystadenoma of the appendix with myxoglobulosis associated to cecal adenocarcinoma. Appendiceal myxoglobulosis present typical gross and microscopical findings. The clinical diagnosis of myxoglobulosis should be followed by a careful evaluation of the patient in order to detect an appendicular neoplasm and/or an assoiciated occult intestinal carcinoma.

[Immunoglobulin levels at different ages in the healthy child population]

In this study, we report the IgE, IgA, IgM and IgG levels in the serum and the secretory IgA obtained from a group of children of different ages with normal morphgram, with no personal or family history of allergies and without recurrent infectious diseases. The IgG, IgA and IgM and salivary secretory IgA were determined by the immunonephelometry technique, using specific anti-serum for heavy chains obtained form rabbits and purified by affinitive chromatography. The IgE was determined by radioimmunoassay, using the PRIST technique. If we look at all published works about normal levels of immunoglobulins in serum, we can see many differences among the results obtained by different authors. Our results are different as well; however, there is no difference in IgE levels. In our work, the secretory IgA level cannot be compared as we do not have any other study available for comparison. We think that our results differ from those obtained by other authors because of differences in laboratory and statistical techniques and other factors such as environment, constitution, nutrition, etc.