Biomedical subjects

D M Jacobowitz

Publications and source records attributed to D M Jacobowitz.

At least 91 records · Page 5Linked to original sources

PubMed1992

Calretinin distribution in the thalamus of the rat: immunohistochemical and in situ hybridization histochemical analyses.

The distribution of calretinin-containing cells was examined by in situ hybridization histochemistry and compared with the immunohistochemical mapping of calretinin in the thalamus of the rat. Results revealed a close correspondence between the immunohistochemical localization of cell bodies and the messenger RNA label produced by the calretinin oligonucleotide probe. Calretinin cells were most prominent in the midline (paraventricular, reuniens, rhomboid) and intralaminar (central medial, paracentral) nuclei and in a group of cells along the rostral central gray which appeared continuous with the caudal extent of the midline nuclei. A subpopulation of calretinin cell bodies was also identified in the reticular nucleus. The mediorostral lateral posterior nucleus, subparafascicular, lateral geniculate and habenular nuclei also contained calretinin messenger RNA probe label. In contrast, no positive cells were found in the anterior, ventral or posterior thalamic nuclei. The distribution of calretinin cells did not correspond directly with that of other histochemical markers. Thus, the in situ hybridization histochemical and immunohistochemical results revealed calretinin as a unique identifying marker for distinct sets of thalamic neurons.

Animals↗

PubMed1992

A rabbit autoantibody specific for the 46-kDa form of 2',3'-cyclic nucleotide 3'-phosphodiesterase.

An autoantibody occurring in the serum of an apparently normal rabbit that immunocytochemically stains myelin sheaths and oligodendrocytes in rat brain was shown to react specifically with the 46-kDa isoform of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) (EC 3.1.4.37) in a number of species. Identification of the shorter isoform of the enzyme (CNP1) as the antigen was achieved by comparing the immunostaining of Western blots by the autoantibody with that of a well-characterized anti-CNP antiserum. The 46-kDa antigen reacting with the autoantibody exhibited the same Mr and pI as the small isoform of CNP on two-dimensional gels and showed a similar enrichment in purified CNS myelin. The autoantibody has very high affinity for CNP1 and is capable of detecting the very low amounts of this enzyme in peripheral nerve, spleen, adrenal gland, pancreas, testis, and intestine. Testing the reactivity of the autoantibody with synthetic peptides by enzyme-linked immunosorbent assay revealed that it reacted with the N-acetylated decapeptide corresponding to the N-terminus of CNP1, but did not react if the peptide was not acetylated or if the acetyl group was replaced with a palmityl group. The lack of reactivity with CNP2, which differs from CNP1 by a 20-amino acid extension at the N-terminus of the protein as a result of alternative splicing, may be due to the absence of the N-acetyl moiety that is part of the epitope and/or blocking of antibody binding to the decapeptide by extension of the polypeptide chain.(ABSTRACT TRUNCATED AT 250 WORDS)

2',3'-Cyclic-Nucleotide Phosphodiesterases↗

PubMed1991

Differential distribution of AT1 and AT2 angiotensin II receptor subtypes in the rat brain during development.

Angiotensin II (AII) receptor subtypes were analyzed in the brains of adult and 2-week-old rats by in vitro autoradiography with 125I-labeled [Sar1,Ile8]AII and competition studies with three AII antagonists: the nonpeptide antagonist, DuP 753, which is specific for AT1 receptors that mediate the calcium-inositol phospholipid signaling actions of AII; and nonpeptide (PD 123177) and peptide (CGP 42112A) antagonists that are selective for AT2 receptors of yet unknown function. In the adult rat brain, DuP 753 inhibited radioligand binding to the circumventricular organs and paraventricular nucleus but not to the lateral septum, subthalamic nucleus, and inferior olive. However, binding of 125I-labeled [Sar1,Ile8]AII in the latter regions was inhibited by the AT2 receptor antagonists PD 123177 and CGP 42112A. These areas showed similar displacement by the AT2 receptor subtype-specific antagonists in 2-week-old rats. In addition, radioligand binding at multiple sites of transient expression of AII receptors in 2-week-old rats, including several thalamic nuclei, the nuclei of the 3rd and 12th cranial nerves, geniculate bodies, cerebellum, and cingulate cortex, was displaced by the AT2 antagonists but not by DuP 753. These studies have demonstrated the presence of two AII receptor subtypes in the brain, one (AT1) in areas related to regulation of blood pressure, water intake, and pituitary hormone secretion, and one (AT2) whose function is not yet defined. The abundance and location of brain AT2 receptors in young animals, and the age-related changes in relative expression of the receptor subtypes, suggest that AII exerts specific actions according to the developmental stage of the central nervous system.

Aging↗

PubMed1991

Calretinin, a neuronal calcium binding protein, inhibits phosphorylation of a 39 kDa synaptic membrane protein from rat brain cerebral cortex.

The neuronal calcium binding protein calretinin was studied for possible effects on brain protein phosphorylation. Calretinin (100 nM) inhibited the appearance of a calcium stimulated 39 kDa phosphoprotein within a synaptic membrane fraction following sucrose density centrifugation. Calmodulin or a specific protein kinase C inhibitor had no effect on either the phosphorylation of the 39 kDa protein or the inhibition produced by calretinin. At the same concentration, calretinin produced a slight increase in the phosphorylation of several other synaptic membrane proteins which appeared additive with the stimulation produced by either calmodulin or phosphatidylserine in the presence of calcium.

Adenosine Triphosphate↗

PubMed1991

Identification and ultrastructural localization of a calretinin-like calcium-binding protein (protein 10) in the guinea pig and rat inner ear.

Calretinin has been identified as a brain specific calcium-binding protein which appears as a prominent protein in the cochlear nucleus. We identified and localized calretinin in the guinea pig and rat inner ear using polyclonal antibodies. Immunoblot analyses of guinea pig and rat auditory nerve homogenates revealed an immunoreactive band migrating with the same molecular weight as the purified protein, at Mr = 29 k. Immunocytochemistry was carried out at the light and electron microscope levels. In the guinea pig cochlea, inner hair cells, Deiters' cells, Hensen's cells and interdental cells of the spiral limbus were stained. Most of the cochlear ganglion cells were immunostained. In the guinea pig vestibular organs, the staining was exclusively neuronal and localized in large nerve fibers and nerve calices of the apex of the cristae. Only some vestibular ganglion cells were stained. In the rat cochlea, inner hair cells and most of the ganglion neurons were immunoreactive. In the rat vestibule, large nerve fibers and calices were stained as were some type II hairs cells. Only some vestibular ganglion cells were reactive. Electron microscopic observations of immunostained guinea pig cochlea and vestibule showed that the staining was cytosolic. In addition, specific sub-localization was also found in the apical portion of the nerve calices in association with microvesicles. These results describe the discrete localization of calretinin in the cochlea and in the vestibular receptors and suggest a function associated with biochemical regulations at the level of microvesicles in vestibular afferent neurons.

Animals↗

PubMed1991

Calretinin-immunoreactivity in vagal and glossopharyngeal sensory neurons of the rat: distribution and coexistence with putative transmitter agents.

Immunoreactivity for the calcium binding protein, calretinin (calretinin-ir), was demonstrated in cell bodies of vagal and glossopharyngeal sensory ganglia (jugular, petrosal, and nodose ganglia) and in associated nerve fibers. In the jugular and petrosal ganglia, many calretinin-ir neurons were also immunoreactive for calcitonin gene-related peptide and substance P. In the nodose ganglion, most of the calretinin-ir neurons lacked these peptides. None of the calretinin-ir neurons in these ganglia were also immunoreactive for tyrosine hydroxylase.

Animals↗

PubMed1991

Immunohistochemical localization of calretinin in the rat hindbrain.

The localization of calretinin in the rat hindbrain was examined immunohistochemically with antiserum against calretinin purified from the guinea pig brain. Calretinin immunoreactivity was found within neuronal elements. The distribution of calretinin-immunoreactive cell bodies and fibers is presented in schematic drawings and summarized in a table. Major calretinin-immunoreactive neurons were found in the lateral and medial geniculate nuclei, substantia nigra, ventral tegmental area, interpeduncular nucleus, periaqueductal gray, mesencephalic trigeminal nucleus, superior and inferior colliculi, pontine nuclei, parabrachial nucleus, dorsal and laterodorsal tegmental nuclei, cochlear nuclei, vestibular nuclei, medullary reticular nuclei, nucleus of the solitary tract, area postrema, substantia gelatinosa of the spinal trigeminal nucleus, and cerebellum. These results show that distinct calretinin-immunoreactive neurons are widely distributed in the rat hindbrain.

Animals↗

PubMed1991

Immunocytochemical localization of calretinin in the forebrain of the rat.

The distribution of the calcium binding protein calretinin (protein 10) was examined in the rat forebrain by immunohistochemistry. The main and accessory olfactory bulbs had immunoreactive label in granule, periglomerular, and mitral cells. Positive fibers were noted in the external plexiform and granule cell layers, glomeruli, and in the molecular layer of the anterior olfactory nucleus. The cerebral cortex contained calretinin label in nonpyramidal bipolar cells. Cells in the substantia nigra compacta and ventral tegmental area were also calretinin positive as were nigrostriatal and mesolimbic projections (caudate-putamen, nucleus accumbens). In the hippocampus, interneurons were stained in all the subfields of the CA1-CA4 regions. In the thalamus, many positive cells were observed in the periventricular, reticular, lateral habenula, and reunions nuclei. Calretinin immunoreactive cells were particularly abundant in the lateral mamillary and septofimbrial nuclei. Several fiber tracts were also revealed, i.e., the lateral olfactory tract, mamillothalamic tract, fasciculus retroflexus, optic tract, and stria medullaris. These results demonstrate a distinct distribution of calretinin within cell bodies and fibers.

Animals↗

PubMed1991

Extracellular matrix permits the expression of von Willebrand's factor, uptake of di-I-acetylated low density lipoprotein and secretion of prostacyclin in cultures of endothelial cells from rat brain microvessels.

Microvascular endothelial cells from the adult rat brain were cultured on Matrigel and found to express many differentiated properties including secretion of prostacyclin (PGI2) and von Willebrand's factor (vWF). Brain microvascular endothelial cells (BMECs) were purified by dextran and percoll gradients after enzymatic treatment and cultured under various conditions. BMECs that were plated on Matrigel stained positively for factor VIII-related antigen and incorporated Di-I-acetylated low density lipoprotein, whereas BMEC plated on fibronectin, gelatin, or uncoated dishes did not express any of the above properties which are characteristic of endothelial cells. vWF was measured by a sensitive ELISA in the culture media of BMECs plated on different types of matrices. Specificity of the anti-human vWF antibodies for the rat vWF was verified by immunoabsorption on a solid phase, sodium dodecyl sulfate, and Western blot analysis. BMECs also secreted vWF into the culture media only when the cells were plated on Matrigel, and this secretion was augmented after a 6 h incubation with an interleukin-1 tumor necrosis factor-alpha mixture, but not by lipopolysaccharide. From different matrices tested, only Matrigel permitted the secretion of PGI2 by BMECs. Cells also proved to be sensitive to mechanical stimulation and became refractory to secretagogue if the mechanical stimulation was serially repeated. Under the best conditions, stimulation of the cells with bradykinin (1 microM) substantially increased PGI2 secretion. These data indicate that growth of BMECs on Matrigel in vitro permits the expression of classical endothelial cell markers in a manner similar to the behavior of these cells in situ.

Acetylation↗

PubMed1991

Neurochemicals in the dorsal pontine tegmentum.

Detailed maps of neurochemicals in the locus coeruleus and adjacent dorsal tegmental areas are discussed in this chapter. The locus coeruleus appears to be one of the most complex brain regions with six neurochemicals (acetylcholinesterase, tyrosine hydroxylase, galanin, neuropeptide Y, neurotensin, and vasoactive intestinal protein) contained within the cell bodies.

Acetylcholinesterase↗

PubMed1991

Fetal nondopaminergic neural implants in parkinsonian primates. Histochemical and behavioral studies.

Implantation of fetal dopamine-containing tissue into preformed cavities in the caudate nucleus of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonian monkeys leads to behavioral recovery. Recovery may be related to two sources of dopamine: the grafted cells and/or the sprouted fibers from host dopaminergic neurons. The authors undertook this study to determine whether behavioral recovery requires release of dopamine by the implanted tissue, and to establish if nondopaminergic fetal central nervous system implants can induce sprouting of dopamine fibers in the primate brain and cause behavioral recovery. Rhesus monkeys with MPTP-induced hemiparkinsonism or full parkinsonism and a stable neurological deficit were used for this study. Cavities were created in the caudate nuclei anterior to the foramen of Monro via an open microsurgical approach. Fetal cerebellum or spinal cord was implanted into the preformed cavities of three monkeys. Control parkinsonian monkeys showed no recovery. However, implant-induced improvement was stable for up to 6 months after implantation. Sprouted dopaminergic fibers oriented from the ventral striatum and nucleus accumbens were found in the area of the tissue implant in the animals that received fetal grafts but were not present in the control monkeys. It is concluded that brain implants do not need to contain dopamine to induce functional recovery in MPTP-induced parkinsonian primates. Implant-induced and trophic factor-mediated dopaminergic sprouting by the host brain plays a role in the behavioral recovery and may well be responsible for the clinical improvement seen in parkinsonian patients after brain implants.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1990

Antibody to a soluble protein purified from brain selectively labels layer V corticofugal projection neurons in rat neocortex.

An antibody to a soluble protein (protein 36) isolated and purified from rat brain labels the cell bodies and processes of pyramidal cells within layer V of the rat neocortex. We have used the fluorescent retrograde axonal tracer, Fast blue, in combination with FITC immunocytochemistry to determine the projection sites of the cortical neurons detected by this antibody. Retrogradely labeled pyramidal tract neurons and corticotectal neurons are labeled with the protein 36 antibody, but the callosally projecting neurons within layer V are not. Thus within the neocortex the antibody to protein 36 may selectively detect a particular class of neuron, the corticofugal projection neurons of layer V.

Animals↗

PubMed1990

A synthetic oligonucleotide probe encoding for atrial natriuretic peptide detects specific mRNA transcripts in rat heart but not brain using in situ hybridization histochemistry.

In situ hybridization histochemical techniques were used in an attempt to demonstrate atrial natriuretic peptide (ANP) messenger RNA (mRNA) in the rat brain. A synthetic oligonucleotide derived from previously reported ANF cDNA sequence was used as a probe. Northern blot analysis of total RNA isolated from rat heart demonstrated that the oligonucleotide recognized a single species of RNA (0.9 kb), a size consistent with previous reports. Rat heart sections revealed dense accumulations of ANF mRNA in the cardiac atria and lesser densities in the ventricles. Rat brain sections hybridized with the same oligonucleotide did not label ANF mRNA accumulations in any neuronal cell bodies. A possible explanation for this latter observation is either sparsely distributed expressing neurons or low expression and high turnover of ANF mRNA in brain.

Animals↗

PubMed1990

Localization of substance P mRNA in cholinergic cells of the rat laterodorsal tegmental nucleus: in situ hybridization histochemistry and immunocytochemistry.

1. In situ hybridization histochemical techniques in combination with immunocytochemistry and acetylcholinesterase (AChE) histochemistry were used to study the colocalization of messenger RNA (mRNA) encoding the neuropeptide substance P (SP) in cholinergic cells of the laterodorsal tegmental nucleus (LDT) of the rat pontine brain stem. 2. Alternate serial sections were hybridized with a 48-base, 35S-labeled synthetic oligonucleotide probe encoding SP using in situ hybridization histochemistry and processed either histochemically for AChE or immunocytochemically for choline acetyltransferase (ChAT). 3. In addition, serial section analysis was used to demonstrate the correlation between SP and SP mRNA in the same cells of the LDT. 4. These studies reveal that the cholinergic neurons of the LDT synthesize SP.

Acetylcholinesterase↗

PubMed1990

Detection of CCK mRNA in the motor nucleus of the rat trigeminal nerve with in situ hybridization histochemistry.

The regional distribution of dorsal pontine tegmental neurons expressing cholecystokinin (CCK) messenger RNA (mRNA) was examined using in situ hybridization histochemical techniques. A distribution of neurons containing CCK mRNA was observed in the motor nucleus of the trigeminal nerve, a region which has not been shown to contain CCK by immunocytochemical means. In addition, CCK mRNA was seen in the caudal portion of the dorsal raphe nucleus which correlates with prior immunocytochemical observations. The presence of CCK mRNA in the cholinergic motor trigeminal nucleus suggests that these cells express the CCK gene and have gone undetected in previous immunocytochemical studies. It is also suggested that CCK may have an influence on muscular contraction at sites of trigeminal nerve innervation (e.g. muscles of mastication).

Animals↗

PubMed1990

A novel autoantibody from a rabbit preimmune serum that immunostains myelinated nerves of the brain.

Preimmune serum from a rabbit was found to contain antibodies that selectively immunostained myelin in brain sections of the rat. It also reacted with oligodendroglial cells in culture as shown by double labeling with galactocerebroside. On Western blots of two-dimensional electrophoretic gels of rat cortex, this antiserum recognized a 46 kD protein with a basic pI. The presence of this protein within myelin may help identify possible cellular mechanisms of myelination and the autoimmune serum might be useful in structural studies of myelin.

Animals↗

PubMed1990

The effect of fetal mesencephalon implants on primate MPTP-induced parkinsonism. Histochemical and behavioral studies.

Parkinsonism or hemiparkinsonism was induced by administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in four rhesus monkeys, which then received homologous fetal mesencephalon implants into the caudate nuclei. Cavities were prepared in the medial caudate nucleus 2 to 5 weeks before the fetal grafts were implanted. Control studies were conducted in unoperated MPTP-treated animals. Significant behavioral improvement, which occurred within weeks of implantation of fetal mesencephalon, was sustained for up to 7 months. No recovery was seen in the unoperated control animals. Histological examination revealed numerous surviving tyrosine hydroxylase (TH)-immunoreactive cell bodies. In addition to the graft, abundant TH-immunoreactive fibers were observed in the host caudate nucleus ventral to the region of the implanted and the nonimplanted cavities. Since TH-immunoreactive cell bodies of the substantia nigra compacta (A-9 cells) were destroyed by MPTP treatment and the ventral tegmental area (A-10) remained intact, it is concluded that sprouting of remaining host dopaminergic fibers occurs. These newly formed fibers appeared to emanate from the mesolimbic projection to the striatum. It is likely that the newly sprouted dopaminergic fibers account for the motor improvement elicited by precavitation and fetal mesencephalon implantation. These results suggest that the mechanism of recovery of parkinsonian primates after implantation of fetal dopaminergic tissue into the caudate nucleus is by stimulation of sprouting from host neurons. They also suggest that, with identification of the factors responsible for the formation of the new dopaminergic neuronal processes and with further development, tissue implantation may be an effective therapy for Parkinson's disease in humans.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1990

Serum autoantibodies in type 1 (insulin-dependent) diabetes mellitus: identification of reactivity against a 29 kd pancreas-specific protein.

Serum samples from patients with type 1 (insulin-dependent) diabetes mellitus and controls were incubated with two-dimensional Western immunoblots of pancreas and other tissues. Two out of 26 (8%) of the diabetics and 0 out of 45 of the controls demonstrated reactivity against four pancreas-specific proteins with identical molecular weights of 29,000 daltons and different isoelectric points ranging from pH 7.0-8.0. It is concluded that 29 Kd autoantibody reactivity is not a major marker for type 1 diabetes, but may help identify a subgroup of type 1 diabetics.

Adolescent↗