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Distinct mutational signatures characterize concurrent loss of polymerase proofreading and mismatch repair. Nat Commun 2018; 9:1746. [PMID: 29717118 PMCID: PMC5931517 DOI: 10.1038/s41467-018-04002-4] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 03/26/2018] [Indexed: 12/19/2022] Open
Abstract
Fidelity of DNA replication is maintained using polymerase proofreading and the mismatch repair pathway. Tumors with loss of function of either mechanism have elevated mutation rates with characteristic mutational signatures. Here we report that tumors with concurrent loss of both polymerase proofreading and mismatch repair function have mutational patterns that are not a simple sum of the signatures of the individual alterations, but correspond to distinct, previously unexplained signatures: COSMIC database signatures 14 and 20. We then demonstrate that in all five cases in which the chronological order of events could be determined, polymerase epsilon proofreading alterations precede the defect in mismatch repair. Overall, we illustrate that multiple distinct mutational signatures can result from different combinations of a smaller number of mutational processes (of either damage or repair), which can influence the interpretation and discovery of mutational signatures. Polymerase proofreading and the mismatch repair pathway maintain the fidelity of DNA replication. Here the authors show that tumors with concurrent loss of function of both pathways lead to mutation signatures that are not simply a sum of the signatures found in tumors involving single alteration.
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Whole-genome sequencing reveals activation-induced cytidine deaminase signatures during indolent chronic lymphocytic leukaemia evolution. Nat Commun 2015; 6:8866. [PMID: 26638776 PMCID: PMC4686820 DOI: 10.1038/ncomms9866] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 10/08/2015] [Indexed: 12/17/2022] Open
Abstract
Patients with chromosome 13q deletion or normal cytogenetics represent the majority of chronic lymphocytic leukaemia (CLL) cases, yet have relatively few driver mutations. To better understand their genomic landscape, here we perform whole-genome sequencing on a cohort of patients enriched with these cytogenetic characteristics. Mutations in known CLL drivers are seen in only 33% of this cohort, and associated with normal cytogenetics and unmutated IGHV. The most commonly mutated gene in our cohort, IGLL5, shows a mutational pattern suggestive of activation-induced cytidine deaminase (AID) activity. Unsupervised analysis of mutational signatures demonstrates the activities of canonical AID (c-AID), leading to clustered mutations near active transcriptional start sites; non-canonical AID (nc-AID), leading to genome-wide non-clustered mutations, and an ageing signature responsible for most mutations. Using mutation clonality to infer time of onset, we find that while ageing and c-AID activities are ongoing, nc-AID-associated mutations likely occur earlier in tumour evolution. The oncogenic events driving indolent chronic lymphocytic leukaemia are relatively unknown. Here, the authors perform whole genome sequencing on 30 such tumours and identify recurrent mutations in IGLL5 and two activation induced cytidine deaminase signatures that are operative at different stages of CLL evolution.
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Exploration of the African green monkey as a preclinical pharmacokinetic model: oral pharmacokinetic parameters and drug–drug interactions. Xenobiotica 2009; 39:266-72. [DOI: 10.1080/00498250802657718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
The RNA world hypothesis regarding the early evolution of life relies on the premise that some RNA sequences can catalyze RNA replication. In support of this conjecture, we describe here an RNA molecule that catalyzes the type of polymerization needed for RNA replication. The ribozyme uses nucleoside triphosphates and the coding information of an RNA template to extend an RNA primer by the successive addition of up to 14 nucleotides-more than a complete turn of an RNA helix. Its polymerization activity is general in terms of the sequence and the length of the primer and template RNAs, provided that the 3' terminus of the primer pairs with the template. Its polymerization is also quite accurate: when primers extended by 11 nucleotides were cloned and sequenced, 1088 of 1100 sequenced nucleotides matched the template.
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The calcium-sensing receptor regulates calcium absorption in MDCK cells by inhibition of PMCA. Am J Physiol Renal Physiol 2001; 280:F815-22. [PMID: 11292623 DOI: 10.1152/ajprenal.2001.280.5.f815] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Calcium transport across a monolayer of Madin-Darby canine kidney (MDCK) cells was measured in response to stimulation of the basal surface with calcium-sensing receptor (CaR) agonists. Stimulation of the CaR resulted in a time- and concentration-dependent inhibition of calcium transport but did not change transepithelial voltage or resistance. Inhibition of transport was not altered by pretreatment of cells with pertussis toxin but was blocked by the phospholipase C (PLC) inhibitor U-73122. To determine a potential mechanism by which the CaR could inhibit calcium transport, we measured activity of the plasma membrane calcium ATPase (PMCA). Stimulation of the CaR on the basal surface resulted in an inhibition of the PMCA in a concentration- and PLC-dependent manner. Thus stimulation of the CaR inhibits both calcium transport and PMCA activity through a PLC-dependent pathway. These studies provide the first direct evidence that calcium can inhibit its own transcellular absorption in a model of the distal tubule. In addition, they provide a potential mechanism for the CaR to inhibit calcium transport, inhibition of PMCA.
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Gene therapies that enhance hippocampal neuron survival after an excitotoxic insult are not equivalent in their ability to maintain synaptic transmission. Exp Neurol 2000; 166:180-9. [PMID: 11031094 DOI: 10.1006/exnr.2000.7500] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Research shows that overexpression of cytoprotective genes can spare neurons from necrotic death, but few studies have addressed the functional status of surviving neurons. Overexpression of a brain glucose transporter, Glut-1, or the anti-apoptotic protein, Bcl-2, in rats decreases the size of hippocampal lesions produced by kainic acid (KA) treatment. In animals in which KA-induced lesions are reduced to similar extents by Glut-1 or Bcl-2 overexpression, spatial learning is spared by Glut-1, but not Bcl-2. We postulated that Glut-1 and Bcl-2 act differently to protect hippocampal function and investigated the effects of vector overexpression on synaptic physiology after KA treatment. Three days after KA and vector delivery to the dentate gyrus, mossy fiber-CA3 (MF-CA3) population excitatory postsynaptic potentials (EPSPs) were recorded in vitro. In addition to producing a lesion in area CA3, KA treatment reduced baseline MF-CA3 synaptic strength, posttetanic potentiation (PTP), and long-term potentiation (LTP). A similar reduction in the KA-induced lesion was produced by overexpression of Glut-1 or Bcl-2. Glut-1, but not Bcl-2, attenuated the impairments in synaptic strength and PTP. Overexpression of Glut-1 or Bcl-2 preserved LTP after KA treatment. Results indicate greater protection of MF-CA3 synaptic transmission with overexpression of Glut-1 compared to Bcl-2 and suggest that not all neuroprotective gene therapy techniques are equivalent in their ability to spare function.
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Abstract
STUDY DESIGN This study used a prospective cohort design. OBJECTIVE To examine factors associated with favorable self-reported patient outcomes 1 year after elective surgery for degenerative back problems. SUMMARY OF BACKGROUND DATA Many previous studies addressing the results of low back surgery have been conducted in academic institutions or by single surgeons. As part of a quality improvement effort, surgeons in private practice led a community-based outcomes management project in Washington State. METHODS Patients ages 18 and older with the following diagnoses were eligible for the study: degenerative changes, herniated disc, instability, and spinal stenosis. Nine orthopedists and neurosurgeons enrolled a total of 281 patients. Participants were asked to complete baseline and 1-year follow-up surveys. Data concerning diagnoses, clinical signs, and operative procedures were provided by the surgeons. The researchers examined sociodemographic characteristics, self-reported symptoms before surgery, preoperative clinical signs, diagnoses, and operative procedures associated with three primary outcomes: better functioning, improved quality of life, and overall treatment satisfaction. RESULTS Follow-up surveys were completed by 236 (84%) of the enrolled patients. Approximately two thirds of the study participants reported much better functioning (65%), a great quality of life improvement (64%), and a very positive perspective about their treatment outcome (68%). The following variables were associated with worse patient outcomes: older age, previous low back surgery, workers' compensation coverage, and consultation with an attorney before surgery. Patients undergoing a fusion procedure were more likely to report good outcomes. CONCLUSIONS The authors' experience indicates that community-based outcomes data collection efforts are feasible and can be incorporated into usual clinical practice. The study results indicate that compensation payments and litigation are two important predictors of poor outcomes after low back surgery in community practice. Because of small numbers, varied diagnoses, and possible selection bias, the findings with respect to fusion should be interpreted cautiously.
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Abstract
The calcium-sensing receptor (CaR) stimulates ERK1 in rat fibroblasts, but its effect on other MAP kinases is not known. We used a model of renal distal tubule, the MDCK cell, to determine the effects of CaR stimulation on Jun kinase (JNK) activity. Stimulation of the CaR with 5 mM Ca(2+) resulted in a time-dependent increase in JNK activity. Activation of JNK occurred preferentially with stimulation on the basal surface relative to the apical surface. Basal administration of the CaR agonist gadolinium (30 microm) also stimulated JNK activity. Pertussis toxin blocked the ability of both CaR agonists to stimulate JNK, indicating that the effect was mediated through G(ialpha) class G proteins. Finally, we used confocal microscopy to determine that the CaR was located predominantly on the basal surface. These studies demonstrate for the first time that the CaR stimulates JNK activity.
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Abstract
Considerable attention has focused on the therapeutic transfer of genes with viral vectors into neurons for the purpose of protecting against neurological insults. A number of papers have reported that overexpression of the anti-apoptotic protein Bcl-2 can protect neurons both in vitro and in vivo against a variety of necrotic insults. An emerging literature suggests that the availability of energy tends to modulate a neuron towards dying apoptotically, rather than necrotically, in the aftermath of an insult. This suggests that an anti-apoptotic protein such as Bcl-2 should be minimally protective, at best, against purely energetic insults. In support of this idea, we report that overexpression of Bcl-2 with a herpes simplex viral vector fails to protect hippocampal neurons, either in vitro or in vivo, against the electron transport uncoupler 3-acetylpyridine (3AP). As a positive control, the same vector significantly protected against the excitotoxin kainic acid. This finding supports the view that neurotoxicity induced by 3AP is likely to have only minimal apoptotic facets. On a broader level, it suggests some limitations in the neuroprotective potential of gene therapy with Bcl-2.
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Inflammatory responses and their impact on beta-galactosidase transgene expression following adenovirus vector delivery to the primate caudate nucleus. Gene Ther 1999; 6:1368-79. [PMID: 10467361 DOI: 10.1038/sj.gt.3300958] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An E1, E3 deleted adenovirus vector, serotype 5, carrying the marker gene LacZ was bilaterally microinfused into the caudate nuclei of 10 St Kitts green monkeys. The location and number of cells expressing transgene and host immunologic response were evaluated at 1 week (n = 2) and 1 month (n = 8) following vector infusion. A large number of cells expressed beta-galactosidase in some monkeys, exceeding 600000 in one monkey, but no expression was seen in three of 10. All monkeys had positive adenoviral antibody titers before vector infusion, indicating the possibility of previous exposure to some adenovirus, but only one showed a significant increase in titer afterwards. Inflammatory cell markers revealed an inverse correlation between transgene expression and the extent of inflammatory response. Dexamethasone administered immediately before and for 8 days following vector delivery, however, had no effect on transgene expression. The demonstration of significant inflammatory responses in the brain of some individual primates, including demyelination, indicates the need for new generations of adenovirus vectors, or the successful suppression of inflammatory responses, before this vector is suitable for non-cytotoxic clinical applications in the CNS.
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Spontaneous blink rates correlate with dopamine levels in the caudate nucleus of MPTP-treated monkeys. Exp Neurol 1999; 158:214-20. [PMID: 10448434 DOI: 10.1006/exnr.1999.7093] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have suggested a dopaminergic regulation of eye blink rates in human and nonhuman primates. Blockade of either dopamine (DA) D1 or DA D2 receptors or DA depletion induced by the dopaminergic neurotoxin MPTP both decrease spontaneous eye blink rates in monkeys. MPTP-induced decreases in blink rates can be reversed by administration of the full efficacy D1 agonist dihydrexidine, which has also been found to have dramatic antiparkinsonian effects in MPTP-treated animals. Increases in blink rates can also be induced by D1 and D2 agonists in normal animals. In the current study, we have investigated whether blink rates correlate with concentrations of DA or HVA and/or HVA:DA ratios in specific brain regions in MPTP-treated monkeys. Furthermore, the potential relationship between the severity of behavioral indices of parkinsonism and blink rates were examined. We found that (1) blink rates significantly correlate positively with concentration of DA and inversely with HVA:DA ratios in the rostral portion of the ventromedial body of the caudate nucleus (CD), but not other subcortical regions, and (2) that severity of parkinsonism was inversely correlated with blink rate. These data support a dopaminergic regulation of blink rate and suggest that the ventromedial region of the body of the CD may be critically involved in regulation of blink rate.
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Abstract
Considerable interest has focused on the possibility of using viral vectors to deliver genes to the central nervous system for the purpose of decreasing necrotic neuronal injury. To that end, we have previously shown that a herpes simplex virus (HSV) vector expressing Bcl-2 could protect neurons from ischemia. In that study, vector was delivered before the ischemia. However, for such gene therapy to be of clinical use, vectors must be protective even if delivered after the onset of the insult. In the present study, we show that an HSV vector expressing Bcl-2 protects striatal neurons when delivered after focal ischemia. Rats were exposed to middle cerebral artery occlusion for 1 hour, followed by reperfusion, and damage was assessed 48 hours later. Delivery of the Bcl-2 vector 30 minutes after reperfusion (i.e., 1.5 hours after ischemia onset) prevented any significant loss of virally-targeted neurons in the striatum. In contrast, in rats microinfused with a vector only expressing a reporter gene, a highly significant loss of neurons occurred. By 4 hours into the reperfusion period (5 hours after ischemia onset), delivery of the Bcl-2 vector was no longer protective. These data show the efficacy of postinsult gene therapy strategies for the brain, underline the finite length of this temporal therapeutic window, and support the growing evidence attesting to the neuroprotective potential of Bcl-2.
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Overexpression of the glucose transporter gene with a herpes simplex viral vector protects striatal neurons against stroke. J Cereb Blood Flow Metab 1996; 16:181-5. [PMID: 8594048 DOI: 10.1097/00004647-199603000-00001] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Herpes simplex virus vectors bearing a glucose transporter (GT) gene and a marker gene were found to protect neurons against a 1-h focal ischemic insult. Rats receiving the GT vector v alpha22beta gal alpha4GT exhibited a 67.4 +/- 35.3% survival of virally targeted neurons in the ischemic hemisphere compared with the contralateral control (n = 7), whereas rats receiving a control vector exhibited only 32.8 +/- 17.9% survival (n = 9). This significant improvement in survival (105%, p=0.022) suggests that energy failure is an important contributor to the neuropathology of ischemic damage in the striatum, and that it can be alleviated by gene transfer. This is the first demonstration of protection against ischemic cerebral injury by the direct transfer of GT genes to neurons.
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Overexpression of Bcl-2 with herpes simplex virus vectors protects CNS neurons against neurological insults in vitro and in vivo. J Neurosci 1996; 16:486-96. [PMID: 8551333 PMCID: PMC6578652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Previous studies have demonstrated that overexpression of the proto-oncogene bcl-2 can protect neuron and neuron-like cell lines from growth factor deprivation, calcium ionophores, glutamate excitotoxicity, hypoglycemia, free radicals, and lipid peroxidation. To determine whether Bcl-2 exhibits a similar protective effect in CNS neurons, we generated defective herpes simplex virus (HSV) vectors capable of overexpressing Bcl-2 in primary cultures and in the intact brain. Infection of hippocampal cultures with Bcl-2 vectors enhanced neuron survivorship after exposure to adriamycin, a potent oxygen radical generator. Furthermore, dichlorofluorescein measurements indicated that there was a significant reduction in the accumulation of oxygen radicals associated with this insult. Bcl-2 vectors also enhanced survival in cultured neurons after exposure to glutamate and hypoglycemia. Most significantly, the in vivo delivery of the vector protected neurons against adriamycin toxicity in the dorsal horn of the dentate gyrus and focal ischemia in the striatum.
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Defective herpes simplex virus vectors expressing the rat brain glucose transporter protect cultured neurons from necrotic insults. J Neurochem 1995; 65:842-50. [PMID: 7616244 DOI: 10.1046/j.1471-4159.1995.65020842.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Because neurons are postmitotic, they are irreplaceable once they succumb to necrotic insults such as hypoglycemia, ischemia, and seizure. A paucity of energy can exacerbate the toxicities of these insults; thus, a plausible route to protect neurons from necrotic injury would be to enhance their glucose uptake capability. We have demonstrated previously that defective herpes simplex virus (HSV) vectors overexpressing the rat brain glucose transporter (GT) gene (gt) can enhance glucose uptake in adult rat hippocampus and in hippocampal cultures. Furthermore, we have observed that such vectors can maintain neuronal metabolism during hypoglycemia and reduce kainic acid-induced seizure damage. In this study, we have developed bicistronic vectors that coexpressed gt and Escherichia coli lacZ as a reporter gene, which allows us to identify directly neurons that are infected with the vectors. Overexpression of GT from these vectors protected cultured hippocampal, spinal cord, and septal neurons against various necrotic insults, including hypoglycemia, glutamate, and 3-nitropropionic acid. Our observations demonstrate the feasibility of using HSV vectors to protect neurons from necrotic insults. Although this study has concentrated on the delivery of gt, other genes with therapeutic or protective capability might also be used.
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Herpes simplex virus vectors overexpressing the glucose transporter gene protect against seizure-induced neuron loss. Proc Natl Acad Sci U S A 1995; 92:7247-51. [PMID: 7638175 PMCID: PMC41316 DOI: 10.1073/pnas.92.16.7247] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have generated herpes simplex virus (HSV) vectors vIE1GT and v alpha 4GT bearing the GLUT-1 isoform of the rat brain glucose transporter (GT) under the control of the human cytomegalovirus ie1 and HSV alpha 4 promoters, respectively. We previously reported that such vectors enhance glucose uptake in hippocampal cultures and the hippocampus. In this study we demonstrate that such vectors can maintain neuronal metabolism and reduce the extent of neuron loss in cultures after a period of hypoglycemia. Microinfusion of GT vectors into the rat hippocampus also reduces kainic acid-induced seizure damage in the CA3 cell field. Furthermore, delivery of the vector even after onset of the seizure is protective, suggesting that HSV-mediated gene transfer for neuroprotection need not be carried out in anticipation of neurologic crises. Using the bicistronic vector v alpha 22 beta gal alpha 4GT, which coexpresses both GT and the Escherichia coli lacZ marker gene, we further demonstrate an inverse correlation between the extent of vector expression in the dentate and the amount of CA3 damage resulting from the simultaneous delivery of kainic acid.
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Abstract
With its natural propensity to infect and establish life-long latency in neurons, herpes simplex virus type 1 (HSV-1) has been successfully employed by various laboratories as vectors for gene transfer into neurons. However, analysis of its cytopathic effects in vivo and in vitro has been limited. In this study, we examined the cytopathic effects of 2 HSV-1 alpha 4 mutants (ts756 and d120) on adult rat hippocampus and striatum and of d120 on hippocampal neurons in culture. We assessed damage by stringent counting of surviving neurons after infection and demonstrated that while neither ts756 nor d120 infection resulted in any gross anatomical or behavioral changes of the animals, ts756, but not d120, produced a significant amount of damage in the CA4 cell field and dentate gyrus of the hippocampus. Thus, since crude examination is insufficient to detect subtle but significant degrees of neuron loss, the cytopathic effects of HSV or any vector system must be carefully analyzed. Furthermore, we also observed that uninfected cell lysates damaged neurons, both in vivo and in vitro. This cytotoxicity occurred within the first 24 h post-inoculation and probably arose through the activation of glutamate receptors. For the preparation of HSV vectors, purification of the virus from soluble cellular components by a simple pelleting step can significantly decrease such acute toxicity.
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Abstract
Glucocorticoids (GCs), adrenal steroids released during stress, can damage the hippocampus outright and increase hippocampal vulnerability to metabolic insults. Changes in ATP levels were measured in response to aglycemia and to cyanide in cultured hippocampal neurons that had been exposed to high- and low-GC conditions. GCs did not depress baseline ATP levels but did accelerate the rate of the decline in ATP concentrations observed during the metabolic insults. These results support the hypothesis that GCs increase neuronal vulnerability by disrupting cellular metabolism and agree with similar findings in hippocampal astrocytes.
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D1 and D2 dopamine receptors independently regulate spontaneous blink rate in the vervet monkey. J Pharmacol Exp Ther 1991; 259:595-600. [PMID: 1682479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Previous studies have revealed the involvement of a dopaminergic link in the regulation of spontaneous eye blink rate in primates. Based on the effect of dopamine D2 receptor-selective drugs and the anecdotal failure of the partial D1 agonist, SKF 38393, to alter blink rate in monkeys, it was assumed that D1 dopamine receptors did not control blink rate. The recent availability of dihydrexidine, a full D1 agonist, prompted us to reevaluate the role of D1 and D2 receptors in the regulation of blink rate. African green monkeys (n = 5) were used in all studies. Dihydrexidine produced a rapid and dose-dependent (up to 1 mg/kg, i.m.) increase in blink rate. The elevation in blink rate elicited by 0.3 mg/kg dihydrexidine was completely reversed by prior administration of a specific D1 antagonist, SCH 23390 (0.01 mg/kg, i.m.), but was unaffected by prior administration of a specific D2 antagonist, remoxipride (1 mg/kg, i.m.). Treatment with the specific D2 agonist, (+)-4-propyl-9-hydroxynaphthoxazine, led to a rapid and dose-dependent (up to 0.01 mg/kg, i.m.) increase in blink rate. The raised blink rate produced by (+)-4-propyl-9-hydroxynaphthoxazine (0.001 mg/kg) was abolished by pretreatment with remoxipride, but was not influenced by pretreatment with SCH 23390. These data indicate that spontaneous blink rate in the primate can be regulated by both D1 and D2 dopamine receptors. Furthermore, the receptor subtypes appear to affect blink rate in the same direction, yet function independently. Measurement of blink rate may provide a noninvasive method to assess the potency and selectivity of dopamine agonists and antagonists in primates.
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Abstract
Eye blink rates were studied in African green monkeys following relatively specific destruction of substantia nigra and its dopamine projections with the neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Monkeys treated with MPTP had a significantly lower blink rate than controls over a period from two to five and a half months after treatment. Furthermore, the degree of parkinsonism expressed in treated animals was inversely correlated with blink rate. Pharmacologic studies further supported the role of dopamine receptors in the regulation of blink rate. PHNO (4-propyl-9-hydroxynaphoxazine), a potent and highly specific D2 agonist, effective in alleviating parkinsonism, caused a significant transient increase in blink rate, while sulpiride, a D2 antagonist, caused a decrease and blocked the effect of PHNO. Apomorphine and haloperidol, although less specific, had potent and predictable effects based on their interactions with dopamine systems. Blink rate may provide a nonintrusive measure of central dopamine activity that would help to evaluate the progress of Parkinson's disease or treatments which attempt to restore dopamine function.
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Abstract
Systemic administration of the selective D1 antagonist, SCH 23390, caused significant motor changes in healthy African green monkeys. The effects included the parkinsonian signs of motor freezing, incoordination, bradykinesia, poverty of movement, tremor and depressed blink rate. SCH 23390 administered to MPTP-treated monkeys increased existing parkinsonism. The results are of particular interest in light of recent data that demonstrate the effectiveness of dihydrexidine, a full D1 agonist, in alleviating parkinsonism in MPTP-treated monkeys. These data implicate D1 receptors in the functions impaired by Parkinson's disease and suggest the possibility of parkinsonian side effects in the clinical use of this or similar D1 antagonists as treatments for psychiatric disorders.
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Greeks bearing gifts. West J Med 1987. [DOI: 10.1136/bmj.295.6604.995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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List size, screening methods, and other characteristics of practices in relation to preventive care. BMJ : BRITISH MEDICAL JOURNAL 1985; 291:869-72. [PMID: 3931749 PMCID: PMC1416758 DOI: 10.1136/bmj.291.6499.869] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Twenty eight practices carried out a review of patient records for information about preventive procedures on two occasions in 1980 and 1982. We have now undertaken a survey of certain characteristics of the practices in an attempt to demonstrate features associated with effective preventive care. Significant favourable factors are a small list size, the setting up of a formal screening programme for cervical cytology and measuring blood pressure, and few registered patients in social classes IV and V. More successful practices also tend to be training practices, have principals with higher qualifications, and have developed good records organization. Opportunistic screening for cervical cytology and measuring blood pressure was not shown to be more effective than no policy of screening at all.
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Effect of gentamicin and dexamethasone on the natural history of the rat Escherichia coli brain abscess model with histopathological correlation. Neurosurgery 1984; 15:475-83. [PMID: 6387526 DOI: 10.1227/00006123-198410000-00001] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
In a rodent model of Escherichia coli brain abscess, the natural history of the infection was studied and the influence of a glucocorticoid (dexamethasone) and an antibiotic (gentamicin) on the development of brain abscess and the survival of abscess-bearing animals was evaluated. The administration of steroids using three different dosage schedules suppressed the macrophage and glial response, decreased collagen formation, increased the number of pathologically evident bacteria, and decreased host survival. The administration of antibiotics by parenteral routes decreased the number of viable bacteria in the abscess. The simultaneous administration of systemic gentamicin and dexamethasone resulted in increased host survival to a level that was intermediate between that of animals treated with dexamethasone alone and that of those treated with gentamicin alone. Thus, some of the adverse effect of corticosteroids on host survival could be mitigated by the simultaneous administration of antibiotics. Finally, it was observed that the abscess in this model tends to expand along white matter tracks. This path of least resistance may be responsible for the observation that brain abscesses tend to rupture into the ventricle rather than into the subarachnoid space via the cortex.
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Hypertension in general practice. BMJ : BRITISH MEDICAL JOURNAL 1984; 288:1156-7. [PMID: 6424768 PMCID: PMC1441420 DOI: 10.1136/bmj.288.6424.1156-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Abstract
The results of two reviews of practice records for information about various preventive measures are reported. The reviews were conducted two and a half years apart in the same 29 practices, on roughly 6500 records on each occasion. The first review was carried out during a postgraduate education course involving audit. Two main analyses were undertaken: one concerned with the entire record sample and the other with the individual practice results. Important and substantial improvements were shown in both analyses, which were spread throughout the practices and were not confined to practices at the lower end of the range simply "catching up." The change between the reviews in the mean recorded rates for cervical cytology was 56% to 64%; for rubella immunity 28% to 40%; for polio immunity in adults 15% to 21%; for completed primary immunisation 68% to 78%; for recorded blood pressure 53% to 61%; and for smoking information 22% to 30%. Improvement has been steady but the rate of improvement, especially for recording blood pressure and rubella immunity, has increased since the postgraduate education course.
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An evaluation of recorded information about preventive measures in 38 practices. THE JOURNAL OF THE ROYAL COLLEGE OF GENERAL PRACTITIONERS 1981; 31:615-20. [PMID: 7328547 PMCID: PMC1972223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
This paper reports the results of a review of practice records for information about various preventive measures; 8,500 records from 38 practices were studied. In collecting the data a Practice Activity Analysis data sheet was used.The results are presented in a way which makes it possible for others undertaking these analyses to compare their results with those reported here. They point to a number of conclusions, in particular:1. Much less cervical cytology has been done for women in their 50s than for those in their 30s and 40s; in particular 45 per cent of women in their 50s have never had a smear.2. Only 35 per cent of girls aged 15 to 19 were known to be immune to rubella.3. Only 14 per cent of adults aged 20 to 40 were known to be immune to polio.4. Of men in their 40s, 47 per cent had no record of their blood pressure having been taken during the previous 10 years.5. Information about smoking habits was available in 23 per cent of records.
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31
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Celiac axis compression syndrome. Can J Surg 1971; 14:122-6. [PMID: 5554003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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32
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33
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Selected characteristics of the members of the National Medical Association: preliminary findings. J Natl Med Assoc 1970; 62:1-7. [PMID: 5445439 PMCID: PMC2611913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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34
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Occlusive disease of the subclavian artery. JOURNAL OF THE IOWA MEDICAL SOCIETY 1969; 59:312-6. [PMID: 5798157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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35
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Pulmonary lesions producing hemoptysis. Etiology and surgical treatment. J Natl Med Assoc 1967; 59:265-8. [PMID: 6043932 PMCID: PMC2611361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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36
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Thoracic-outlet compression syndrome. JOURNAL OF THE IOWA MEDICAL SOCIETY 1967; 57:561-6. [PMID: 6047388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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37
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38
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39
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40
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Results of sympathectomy for arterial occlusive disease at university hospitals, Iowa City, 1954-1964. J Am Geriatr Soc 1966; 14:1122-7. [PMID: 5921510 DOI: 10.1111/j.1532-5415.1966.tb02863.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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41
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42
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43
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Congenital diaphragmatic hernia involving the pleuroperitoneal canal. J Natl Med Assoc 1966; 58:338-41. [PMID: 5919375 PMCID: PMC2611116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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44
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Transatrial and transaortic approaches to subvalvular left ventricular outflow tract obstruction. Correction of associated anomalies in children. Ann Surg 1966; 164:418-27. [PMID: 5927625 PMCID: PMC1477288 DOI: 10.1097/00000658-196609000-00005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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45
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Mediastinal lymph node hyperplasia. Report of a case with growth over an eight year period. J Thorac Cardiovasc Surg 1966; 52:303-8. [PMID: 5965507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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46
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Vascular injuries resulting from trauma. JOURNAL OF THE IOWA MEDICAL SOCIETY 1966; 56:665-9. [PMID: 5937618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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47
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48
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49
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Pulsating supraclavicular tumor: a case report. JOURNAL OF THE IOWA MEDICAL SOCIETY 1966; 56:41-4. [PMID: 5900204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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50
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Trauma to the thoracic aorta. JOURNAL OF THE IOWA MEDICAL SOCIETY 1965; 55:637-643. [PMID: 5838221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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