Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “brain”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources
PubMed2000

Treatment of brain metastases of small-cell lung cancer: comparing teniposide and teniposide with whole-brain radiotherapy--a phase III study of the European Organization for the Research and Treatment of Cancer Lung Cancer Cooperative Group.

PURPOSE: Approximately 60% of patients with small-cell lung cancer (SCLC) develop brain metastases. Whole-brain radiotherapy (WBRT) gives symptomatic improvement in more than 50% of these patients. Because brain metastases are a sign of systemic progression, and chemotherapy was found to be effective as well, it becomes questionable whether WBRT is the only appropriate therapy in this situation. PATIENTS AND METHODS: In a phase III study, SCLC patients with brain metastases were randomized to receive teniposide with or without WBRT. Teniposide 120 mg/m(2) was given intravenously three times a week, every 3 weeks. WBRT (10 fractions of 3 Gy) had to start within 3 weeks from the start of chemotherapy. Response was measured clinically and by computed tomography of the brain. RESULTS: One hundred twenty eligible patients were randomized. A 57% response rate was seen in the combined-modality arm (95% confidence interval [CI], 43% to 69%), and a 22% response rate was seen in the teniposide-alone arm (95% CI, 12% to 34%) (P<.001). Time to progression in the brain was longer in the combined-modality group (P=.005). Clinical response and response outside the brain were not different. The median survival time was 3.5 months in the combined-modality arm and 3.2 months in the teniposide-alone arm. Overall survival in both groups was not different (P=.087). CONCLUSION: Adding WBRT to teniposide results in a much higher response rate of brain metastases and in a longer time to progression of brain metastases than teniposide alone. Survival was poor in both groups and not significantly different.

Adult↗
PubMed1993

A review of brain retraction and recommendations for minimizing intraoperative brain injury.

Brain retraction is required for adequate exposure during many intracranial procedures. The incidence of contusion or infarction from overzealous brain retraction is probably 10% in cranial base procedures and 5% in intracranial aneurysm procedures. The literature on brain retraction injury is reviewed, with particular attention to the use of intermittent retraction. Intraoperative monitoring techniques--brain electrical activity, cerebral blood flow, and brain retraction pressure--are evaluated. Various intraoperative interventions--anesthetic agents, positioning, cerebrospinal fluid drainage, operative approaches involving bone resection or osteotomy, hyperventilation, induced hypotension, induced hypertension, mannitol, and nimodipine--are assessed with regard to their effects on brain retraction. Because brain retraction injury, like other forms of focal cerebral ischemia, is multifactorial in its origins, a multifaceted approach probably will be most advantageous in minimizing retraction injury. Recommendations for operative management of cases involving significant brain retraction are made. These recommendations optimize the following goals: anesthesia and metabolic depression, improvement in cerebral blood flow and calcium channel blockade, intraoperative monitoring, and operative exposure and retraction efficacy. Through a combination of judicious retraction, appropriate anesthetic and pharmacological management, and aggressive intraoperative monitoring, brain retraction should become a much less common source of morbidity in the future.

Adrenal Cortex Hormones↗
PubMed2005

Current strategies in whole-brain radiation therapy for brain metastases.

Whole-brain radiation therapy (WBRT) has been the primary treatment for patients with brain metastases for more than 50 years and provides effective palliative relief in most patients. Although advancements in radiotherapeutic technique continue to improve local and locoregional control, median survival for patients treated with WBRT monotherapy remains fixed at approximately 4 to 6 months. Key issues in the use of WBRT include optimizing its efficacy when it is used in conjunction with surgery, radiosurgery, radiosensitizers, and new chemotherapeutic agents. These multimodal approaches to brain metastases have resulted in significant increases in the median survival time in many patients. Radiosurgery is part of a continuing effort to improve the effects of radiation therapy, especially in brain metastases. The optimal combination of WBRT and radiosurgery remains to be elucidated, including appropriate timing or sequence and use in conjunction with other modalities. Newer radiosensitizing agents (e.g., efaproxiral [RSR-13] and motexafin gadolinium) have shown promise in the treatment of brain tumors, especially in specific patient subsets. Recently developed systemic chemotherapy agents, such as temozolomide, which crosses the blood-brain barrier, have a synergistic effect on brain metastases when used in conjunction with radiation. In addition, the use of interstitial chemotherapy agents provides highly focused local chemotherapy in the brain without increasing systemic toxicity; carmustine polymer wafer, in combination with WBRT, has shown promising results in treating brain metastases.

Biocompatible Materials↗
PubMed1995

Axogenesis in the embryonic brain of the grasshopper Schistocerca gregaria: an identified cell analysis of early brain development.

Axogenesis in the embryonic brain was studied at the single cell level in the grasshopper Schistocerca gregaria. A small set of individually identifiable pioneer neurons establishes a primary axon scaffold during early embryogenesis. At the beginning of scaffold formation, pioneering axons navigate along and between glial borders that surround clusters of proliferating neuroblasts. In each brain hemisphere, an axonal outgrowth cascade involving a series of pioneer neurons establishes a pathway from the optic ganglia to the brain midline. At the midline the primary preoral commissural interconnection in the embryonic brain is pioneered by a pair of midline-derived pioneer neurons. A second preoral commissural connection is pioneered by two pairs of pars intercerebralis pioneer neurons. Descending tracts are pioneered by the progeny of identified neuroblasts in the pars intercerebralis, deutocerebrum and tritocerebrum; the postoral tritocerebral commissure is pioneered by a pair of tritocerebral neurons. All of the pioneering brain neurons express the cell adhesion molecule fasciclin I during initial axon outgrowth and fasciculation. Once established, the primary axon scaffold of the brain is used for fasciculation by subsequently differentiating neurons and, by the 40% stage of embryogenesis, axonal projections that characterize the mature brain become evident. The single cell analysis of grasshopper brain development presented here sets the stage for manipulative cell biological experiments and provides the basis for comparative molecular genetic studies of embryonic brain development in Drosophila.

Animals↗
PubMed2006

Brain temperature and outcome after severe traumatic brain injury.

INTRODUCTION: In humans, raised body temperature is linked to poor outcome after brain injury. Because deviations between brain and body temperature have been reported after severe traumatic brain injury (TBI), the aim of this study was to explore the relationship between initial and mean brain temperature and survival at 3 months. METHODS: Intraparenchymal temperature was measured 3 - 4 cm within white matter. Logistic regression was used to explore linear and quadratic relationships between initial and average brain temperature and survival at 3 months. RESULTS: In 36 patients, initial brain temperatures ranged from 33.5 to 39.2 degrees C (median 37.4 degrees C). There was no evidence of an association between initial brain temperature and risk of death, either linear (odds ratio [OR] 95% confidence interval [CI] = 1.3 [0.68 to 2.5], p = 0.42) or quadratic ( p = 0.26). Assuming a linear relationship, patients with higher mean brain temperatures were less likely to die: OR (95% CI) for death per 1 degrees C was 0.31 (0.09 to 1.1), p = 0.06. However, by fitting the quadratic relationship, there was a suggestion that both high and low temperatures were associated with increased risk of death: p = 0.06. CONCLUSION: Initial brain temperature measured shortly after admission did not predict outcome. There is a suggestion that patients with "middle range" temperatures were less likely to die.

Adult↗
PubMed2005

Stereotactic radiosurgery with and without whole-brain radiotherapy for newly diagnosed brain metastases.

Brain metastases develop in 20-40% of cancer patients and can cause significant morbidity. In selected patients with one to three lesions, stereotactic radiosurgery may be used to improve local control. However, it is unclear whether whole-brain radiotherapy is necessary for all patients who are candidates for stereotactic radiosurgery. While whole-brain radiotherapy may improve the locoregional control of brain metastases, it may cause long-term side effects and may not improve overall survival in some patients. Its benefits should be evaluated in the context of risks of neurocognitive deterioration, either from whole-brain radiotherapy or from uncontrolled brain metastases, and the possible need for salvage treatments with the omission of initial whole-brain radiotherapy. For certain radioresistant brain metastases, the benefit of whole-brain radiotherapy to patients who have stereotactic radiosurgery is uncertain.

Brain Neoplasms↗
PubMed2005

Brain-to-blood transporters for endogenous substrates and xenobiotics at the blood-brain barrier: an overview of biology and methodology.

In the past decade, research into P-glycoprotein involving the blood-brain barrier (BBB) has seen a shift in the concept of the BBB as a structural barrier to that of a functional barrier for xenobiotics and changed simultaneously the strategy for the discovery and development of drugs acting in the CNS. As far as making advances in neurotherapeutics are concerned, the brain-to-blood transport function at the BBB will be one of the most important issues. Knowing the limitations of the in vivo and in vitro methods for BBB efflux research, it is essential to adopt a multidisciplinary approach in investigating the true physiological role of the BBB. Among several methods, the Brain Efflux Index method and the use of conditionally immortalized brain capillary endothelial cell lines, established from transgenic rats harboring temperature-sensitive simian virus 40 large T-antigen gene, are likely to be very useful tools for the BBB efflux transport research. According to our recent findings using these methods, several transporters in the brain capillary endothelial cells appear to play an important role in reducing the brain level of hydrophilic endogenous substrates produced either in the brain or peripheral organs, e.g., neurotransmitters, neuromodulators, metabolites of neurotransmitters, and uremic toxins. It has been reported also that large hydrophilic molecules, such as IgG, apo-transferrin, and amyloid-beta peptide, are susceptible to brain-to-blood efflux transport. In the light of the latest findings, we have formed the hypothesis that the BBB acts as a CNS detoxifying system for both endogenous substrates and xenobiotics in the brain. A fuller understanding of the physiological role of BBB efflux transporters will provide rational insights to assist in the development of safer neurotherapeutics.

Animals↗
PubMed2002

The brain endothelin system as potential target for brain-related pathologies.

The endothelin system, consisting of three peptides, two peptidases and two G-protein coupled receptors, is widely expressed in the brain cell types and brain-derived tumor cell lines. The stimulation of endothelin receptors elicits a variety of short- and long-term changes at cellular level but the effects of the modulation of the endothelin system in brain physiology and pathophysiology are, at the present time, poorly understood. Altered expression of endothelins (ETs) in reactive astrocytes has been observed in many pathological conditions of the human brain, such as infarcts, lacunae, traumatic conditions, Alzheimer's disease and inflammatory diseases of the brain. In addition, recent studies have shown that endothelin antagonists might inhibit growth and induce cell death in human melanoma cells in vitro and in vivo, and have emphasized a possible role of endothelin peptides as autocrine or paracrine factor in the proliferation and dissemination of tumor cell lines. Given the fact that brain cell and a variety of brain tumor cell lines express all the components of the endothelin system, further studies are warranted to demonstrate a possible therapeutic role of endothelin antagonist in the pharmacological treatment of brain diseases and brain tumors.

Amino Acid Sequence↗
PubMed1976

Insulin and brain metabolism. Absence of direct action of insulin on K+ and Na+ transport in mouse brain.

This is a study of the effect of insulin on the transport of K+ and Na+ from the blood into the brains of normal mice. Despite profound reductions in plasma and brain glucose levels, reduction of plasma K+ concentration and progressive deterioration of neurologic function 30-120 minutes after insulin injection, in 20-22-day-old animals there was no increase in brain K+ and Na+ concentrations. In fact, at 120 minutes, when the brain water content increased 0.7 per cent, brain K+ concentration was significantly reduced, not elevated. The effect of insulin on brain electrolyte and water content in adult mice was also studied. Although brain water increased 0.5 per cent at 120 minutes, there was no changes in brain Na+ or K+ concentrations at any time after insulin injection. The data from mice do not support a role of insulin in electrolyte transport in brain.

Age Factors↗
PubMed2004

Gamma knife surgery in the management of brain metastases from lung carcinoma: a retrospective analysis of survival, local tumor control, and freedom from new brain metastasis.

OBJECT: The objective of this retrospective study was to analyze the results of stereotactic radiosurgery performed using a gamma knife in the treatment of 44 consecutive patients with brain metastases from lung carcinoma. METHODS: Forty-four patients with lung carcinoma were treated for metastatic brain tumors by performing radiosurgery with a Leksell Gamma Knife. Twenty-one patients (47.7%) were women and 23 were men. The mean age of the patients was 56 years (range 35-77 years). Twenty-two patients (50%) had solitary tumors and the rest had multiple tumors (two-six lesions). Eighteen patients (40.9%) presented with a recurrent and/or progressive brain disease that previously had been treated with other modalities (surgery, external-beam radiotherapy, or both). Fifteen patients had controlled lung disease and 19 patients had systemic metastases (in lymph nodes, liver, and/or bones) at the time of radiosurgery. The median follow-up period was 18.25 months. All patients were followed up for three different end points: 1) death caused by the disease; 2) clinical and/or radiological evidence of progression of the tumor that had been treated with radiosurgery; and 3) appearance of new lesions. At the last follow-up review, 17 patients (38.6%) were alive and 27 (61.4%) had died. Ten patients (22.7%) died as a result of brain disease (failure of local control or new metastases). Controlled primary disease at the time of detection of metastases and the ability to achieve local tumor control after radiosurgery significantly improved the patient survival (p < 0.01). Control of the treated tumor(s) was achieved in 32 of 44 patients (72 tumors) and 10 patients experienced treatment failure. In addition to the 44 patients comprising the study population, two other patients were treated, but died of lung disease too early in the follow-up period to have been assessed. As of the last follow-up review, no new brain metastasis had occurred in 36 patients (81.8% [includes surviving and nonsurviving patients]). The median duration of overall survival was 7 months, the median period of controlled brain disease was 21 months, and the median period of freedom from new brain metastases was 17 months (95% confidence interval 13-19 months). CONCLUSIONS: Gamma knife surgery has significantly reduced the incidence of mortality from brain disease by effectively accomplishing local tumor control in patients with metastatic lung cancer. Local control and freedom from new brain metastases is not influenced by prior external-beam radiotherapy.

Adult↗
PubMed2000

Induction of IkappaBalpha mRNA expression in the brain by glucocorticoids: a negative feedback mechanism for immune-to-brain signaling.

Peripheral injection of bacterial endotoxin lipopolysaccharide (LPS) induces brain mRNA expression of the proinflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha and the cytokine-responsive immediate-early gene IkappaBalpha. Peripheral LPS also increases levels of plasma glucocorticoids. Whether the induction of IkappaBalpha mRNA in the brain after peripheral LPS injection is caused by the feedback action of glucocorticoids has not been determined. In this study, we examined the mRNA expression of IkappaBalpha and IL-1beta in the rat brain by in situ hybridization histochemistry. Injection of the glucocorticoid agonist dexamethasone induced IkappaBalpha mRNA expression in the brain in a pattern identical to that of LPS injection. LPS but not dexamethasone also induced IL-1beta mRNA expression. Pretreatment with dexamethasone 30 min before LPS injection enhanced the expression of IkappaBalpha mRNA in the brain in a dose-dependent manner. Immobilization of rats for 2 hr (which raises glucocorticoid levels) also induced IkappaBalpha mRNA expression without inducing the expression of IL-1beta. Brain IkappaBalpha expression induced by peripheral LPS injection was attenuated by pretreatment of rats with the glucocorticoid antagonist RU-486. Finally, increased expression of IL-1beta mRNA in the brain was observed at 4 hr after peripheral LPS injection in adrenalectomized rats compared with sham-operated rats. These results reveal that in the brain glucocorticoids selectively induce IkappaBalpha mRNA expression, which serves as a negative feedback mechanism for peripheral LPS-induced synthesis of proinflammatory cytokines. Such an inhibitory control mechanism may be important for preventing prolonged expression of proinflammatory cytokines in the brain after peripheral immune challenge.

Animals↗
PubMed2001

Prospective evaluation of the brain in asymptomatic children with neurofibromatosis type 1: relationship of macrocephaly to T1 relaxation changes and structural brain abnormalities.

BACKGROUND AND PURPOSE: Mutation of the neurofibromatosis type 1 (NF-1) gene may be associated with abnormal growth control in the brain. Because macrocephaly could be a sign of abnormal brain development and because 30% to 50% of children with NF-1 display macrocephaly in the absence of hydrocephalus, we sought to determine the relationship between macrocephaly and other brain abnormalities in young subjects with NF-1. These subjects were free of brain tumor, epilepsy, or other obvious neurologic problems. METHODS: We prospectively screened 18 neurologically asymptomatic subjects with NF-1, ages 6 to 16 years, using clinical measures, psychometric testing, conventional MR imaging, and quantitative MR imaging to measure T1. RESULTS: Cranial circumference was 2 or more SDs above the age norm in seven (39%) of 18 subjects, a frequency of macrocephaly 17-fold higher than normal. Conventional MR imaging showed abnormalities in all 18 children, although there were more extensive abnormalities in subjects with macrocephaly. Macrocephaly in NF-1 was associated with enlargement of multiple brain structures, and brain T1 in macrocephalic subjects was reduced with respect to controls in the genu, frontal white matter, caudate, putamen, thalamus, and cortex. In normocephalic subjects, T1 was reduced only in the genu and splenium. Volumetric analysis showed that macrocephaly was associated specifically with enlargement of white matter volume. CONCLUSION: Neurologically asymptomatic children with NF-1 showed macrocephaly, cognitive deficit, enlarged brain structures, and abnormally low brain T1. Macrocephaly in children with NF-1 may be associated with characteristic alterations in brain development, marked by more widespread and significant changes in T1, greater enlargement of midline structures, and greater volume of white matter.

Adolescent↗
PubMed2003

[Huperzine A attenuates cognitive deficits and brain injury after hypoxia-ischemic brain damage in neonatal rats].

OBJECTIVE: To investigate the protective effects of Huperzine A, a potent acetylcholinesterase inhibitor, against the hypoxic ischemic brain damage (HIBD) of the cognitive and morphology in the neonatal rats. METHODS: Postnatal 7 days old rats were given vehicle or Huperzine A (0.05 mg/kg or 0.1 mg/kg, i.p.) following HIBD (unilateral carotid artery ligation followed by hypoxia) or sham operation, and then tested the learning ability and memory in the Morris water maze (MWM) from 36 to 40 postnatal days. The performance in MWM (escape latency, probe time) were recorded to evaluate the learning and memory dysfunction. At the end of MWM trials, the rats were decapitated and their brains were histologically analyzed. The tissue loss in different brain regions including striatum, cortex, and hippocampus were analyzed by image analysis system. The CA(1) subfield neurons numbers were counted to evaluate the brain damage. The acetylcholinesterase histochemistry staining was used to determine the activity of acetylcholinesterase in different brain regions. RESULTS: Compared with sham-operated group, HIBD rats with the vehicle treatment displayed significant tissue losses in the hippocampus (including CA(1) neurons), cortex, and striatum, as well as severe spatial memory deficits (escape latency: 44 s vs 30 s, P < 0.05, probe time: 14 s vs 40 s, P < 0.01). Huperzine A treatment (0.1 mg/kg) resulted in significant protection against both HI-induced brain tissue losses and spatial memory impairments (mean escape latency: 34 s vs 44 s, P < 0.05, probe time: 35 s vs 14 s,P < 0.01). However, Huperzine A treatment (0.05 mg/kg) did not show any significant improvement of spatial memory impairments (mean escape latency: 45 s vs 44 s, P > 0.05, probe time: 17 s vs 14 s, P > 0.05), but moderate to severe brain tissue losses. There was a pronounced reduction of CA(1) neuron density in ipsilateral hemisphere of vehicle-treated group and 0.05 mg/kg Huperzine A group compared with contralateral hemisphere or ipsilateral hemisphere of sham-operated group and 0.1 mg/kg Huperzine A group (72 vs 232, P < 0.01, 72 vs 229, P < 0.01, respectively). There was a close linear correlation between the CA(1) neurons cell number and the mean escape latency for 5 d acquisition trials (r = 0.777, P < 0.01). CONCLUSION: The unilateral HI brain injury in a neonatal rat model was associated with cognitive deficits, and that Huperzine A treatment may be protective against both brain injury and spatial memory impairment. Huperzine A showed a therapeutic potential for the treatment of hypoxic-ischemic encephalopathy (HIE) caused by the perinatal asphyxia.

Acetylcholinesterase↗
PubMed2004

Imaging endogenous gene expression in brain cancer in vivo with 111In-peptide nucleic acid antisense radiopharmaceuticals and brain drug-targeting technology.

UNLABELLED: Imaging endogenous gene expression with sequence-specific antisense radiopharmaceuticals is possible if the antisense agent is enabled to traverse the biologic membrane barriers that separate the blood compartment from messenger RNA (mRNA) molecules in the cytoplasm of the target cell. The present studies were designed to image endogenous gene expression in brain cancer using peptide nucleic acid (PNA) antisense agents that were modified to allow for (a) chelation of the 111In radionuclide and (b) attachment to a brain targeting system, which delivers the PNA across both the blood-brain barrier (BBB) and the tumor cell membrane. METHODS: PNAs were designed that were antisense to either the rat glial fibrillary acidic protein (GFAP) mRNA or the rat caveolin-1alpha (CAV) mRNA. The PNA contained an amino-terminal diethylenetriaminepentaacetic acid moiety to chelate 111In and a carboxyl-terminal epsilon-biotinyl lysine residue, which enabled attachment to the delivery system. The latter comprised streptavidin (SA) and the murine OX26 monoclonal antibody to the rat transferrin receptor (TfR), which were joined by a thiol-ether linker. Control PNAs were not conjugated to SA-OX26. Brain tumors developed after the intracerebral injection of rat RG2 glial cells in adult Fischer CD344 rats. GFAP and CAV gene expression in the tumor in vivo was monitored by confocal microscopy and Northern blotting with GFAP and CAV complementary DNAs. RESULTS: If the PNA was not targeted to the TfR, then no imaging of any brain structures was possible, owing to the absence of PNA transport across the BBB. Conjugation of the 111In-GFAP-PNA to the SA-OX26 delivery system did not image brain cancer, owing to the downregulation of the GFAP mRNA in brain glial tumors. In contrast, brain cancer was selectively imaged with the 111In-CAV-PNA conjugated to SA-OX26 owing to upregulation of CAV gene expression in brain cancer. CONCLUSION: Imaging endogenous gene expression in vivo with PNA antisense radiopharmaceuticals is possible if drug-targeting technology is used. Attachment of the PNA antisense agent to the targeting ligand enables the antisense radiopharmaceutical to traverse biologic membrane barriers and access intracellular target mRNA molecules.

Animals↗
PubMed1986

The brain-specific gene 1B236 is expressed postnatally in the developing rat brain.

The rat brain-specific polypeptide 1B236 was previously characterized by molecular cloning and nucleotide sequence determination of its mRNA. It has been shown to exist in rat brain in discrete neuronal circuits, primarily as a 100,000 Da glycoprotein. We now have determined the time course of expression of 1B236 mRNA and protein in rat brain during fetal and postnatal development, detecting 1B236 mRNA by RNA blotting and assaying 1B236 protein by electroblotting and radioimmunoassay with antibodies against synthetic peptides. By both indices, expression of the 1B236 gene products is found to be a relatively late event in neuronal development. 1B236 mRNA is first detectable in extracts of whole rat brain at Postnatal Day 5 (PD 5) and increases to a maximum concentration at PD 25. In extracts of dissected brain regions, 1B236 mRNA is first detectable at PD 5 in hindbrain and cerebellum, at PD 9 in midbrain/diencephalon, but not until PD 13 in telencephalon. The appearance of 1B236 protein follows a very similar time course to that of its mRNA in both whole brain and dissected brain regions, suggesting that the expression of the protein during development is regulated largely by transcription of its mRNA. The pattern of 1B236 expression was confirmed by immunocytochemical localization of 1B236 protein: Immunoreactive material can be detected first in spinal cord at PD 3-PD 5 and then appears in progressively more rostral brain regions in increasingly older animals. Several brain regions, however, that do not contain 1B236 immunoreactivity in the adult, such as optic nerve and somatic efferent cranial nerve nuclei, show transient expression of 1B236 during postnatal development.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

The regional distribution and the chemical, chromatographic, and immunologic characterization of motilin brain peptides: the evidence for a difference between brain and intestinal motilin-immunoreactive peptides.

Motilin-like immunoreactive peptides (MLIPs) have been detected in the brain by radioimmunoassay (RIA), (Yanaihara, C., H. Sato, N. Yanaihara, S. Naruse, W. G. Forssman, V. Helmstaedter, T. Fujita, K. Yamaguchi, and K. Abe (1977) Adv. Exp. Biol. Med. 106: 269-283; Chey, W. Y., R. Escoffery, F. Roth, T. M. Chang, and H. Yajima (1980) Regul. Pept. Suppl. 1: 519; O'Donohue, T. L., M. C. Beinfeld, W. Y. Chey, T. M. Chang, G. Nilaver, E. A. Zimmerman, H. Yajima, H. Adachi, M. Roth, R. P. McDevitt, and D. M. Jacobowitz (1981) Peptides 2: 467-477). Previous studies (O'Donohue et al., 1981) demonstrated that MLIPs in rat brain probably differ chemically from porcine intestinal motilin (PIM), the first motilin peptide isolated. The possibility that this rat-pig difference represents a species difference was not examined in the previous study (O'Donohue et al., 1981), neither was the question of the cross-species distribution of MLIP. This study was initiated to examine brain MLIP distribution by RIA in three additional species: cow, pig, and guinea pig. The question of rat-pig species differences was addressed by characterizing MLIP in the brains of these species in comparison to PIM. By RIA, MLIPs were widely distributed in the brains of all species examined. MLIP concentration was highest in rat brain and lowest in pig brain. Some motilin antisera consistently detected less or no MLIPs in some brain regions of all species. Rat pituitary, pineal gland, and retina had substantially higher MLIP concentrations than did brain. MLIPs were abundant throughout the rat gastrointestinal tract and in some other peripheral organs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

Tissue distribution of brain-thymus shared antigens recognized by anti-brain xenosera in the rat, dog and man.

A comparative and quantitative study of the tissue distribution of brain-thymus shared antigens was carried out using rabbit antisera to rat, dog and human brain homogenates, assayed on rat, dog and human thymus cells, respectively. Quantitative absorption analyses with eleven different tissues showed that the tissue distribution of the brain-thymus antigens was strikingly different in the three species. In the rat, the antigens were present in large amounts on both brain and thymus, to a lesser extent on bone marrow cells, but not at all, or only slightly, on the other tissues studied. In the dog, the shared antigens were present in large amounts only on brain. They were present in smaller amounts (approximately 5% compared with brain) on thymus, spleen, lymph node and, unexpectedly, kidney, and to a slight extent on bone marrow cells. In both rat and dog, absorption to a plateau with liver indicated the presence of brain-thymus shared antigens of restricted tissue distribution. No brain-thymus antigens of restricted tissue distribution could be detected in man, since liver, heart, kidney, brain and all other tissue studied, excepting erythrocytes and platelets, could absorb out all the antibody.

Animals↗
PubMed1994

Enhanced expression by the brain matrix of P-glycoprotein in brain capillary endothelial cells.

P-glycoprotein (PGP), an active efflux pump of antitumor agents in multidrug-resistant tumor cells, exists in brain capillary endothelium and could be functionally involved in the blood-brain barrier. To study the regulatory mechanism of PGP expression in brain capillary endothelium, various mouse tissue matrices were tested for their abilities to enhance the expression of PGP in mouse brain capillary endothelial cells (MBEC), which express relatively small amounts of PGP. Of the four tissue matrices we examined, PGP expression in MBEC cultured on the brain matrix increased 2.0-fold. The PGP-inducing activity was similarly detected in bovine brain matrix, and the activity was enriched in the fraction of pl 9.0 by isoelectric focusing. The fraction, named PIC-fraction (PGP-inducing component), increased the PGP expression in MBEC 3.5-fold. By Northern blot analysis, a 3.3-fold enhancement of mdr gene expression was observed in MBEC cultured on the PIC-fraction. The PGP-inducing activity of the PIC-fraction was reduced by the treatment with trypsin but not with collagenase, suggesting that a proteinaceous factor distinct from type I collagen might be responsible for the PGP-inducing activity of PIC-fraction. Although the PIC-fraction increased the PGP expression in other mouse brain capillary endothelial cells, the PIC-fraction did not increase PGP expression in mouse aortic endothelial cells and KB carcinoma cell lines expressing various amounts of PGP. These observations suggest that PGP expression in brain capillary endothelium is specifically regulated by a tissue-specific factor in the brain matrix.

ATP Binding Cassette Transporter, Subfamily B, Mem↗