Some reflections on self-mutilation.
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Humans↗
Biomedical subjects
J C Fowler
Publications and source records attributed to J C Fowler.
Contributions of Na+ flux and the anoxic depolarization to adenosine 5'-triphosphate levels in hypoxic/hypoglycemic rat hippocampal slices.
A 10 min exposure of rat hippocampal slices to hypoxic/hypoglycemic medium decreased tissue adenosine 5'-triphosphate (ATP) levels. Hypoxia/hypoglycemia also caused an anoxic depolarization and essentially no recovery of the synaptically evoked population spike from CA1 region recorded 30 min after re-introduction of normoxic/normoglycemic medium. Removal of Ca2+ or the addition of either the non-competitive N-methyl-D-aspartate antagonist dizocilpine maleate, the inorganic Ca2+ channel antagonist Co2+; or the Na+ channel blocker tetrodotoxin to hypoxic/hypoglycemic medium improved recovery of the evoked population spike upon re-oxygenation. Dizocilpine maleate, Co2+, and tetrodotoxin spared ATP during exposure to hypoxia/hypoglycemia. In contrast, Ca(2+)-free medium facilitated recovery of the population spike but did not preserve ATP during hypoxia/hypoglycemia. Dizocilpine maleate, Co2+ or dantrolene, when added to Ca(2+)-free medium, did not preserve ATP. Tetrodotoxin, when added to Ca(2+)-free medium, was effective in sparing ATP in hypoxic/hypoglycemic medium. To determine the effect of anoxic depolarization on ATP levels, hippocampal slices were collected just before and after the depolarization. There appeared to be an abrupt drop in ATP associated with the anoxic depolarization. We conclude that Na+ influx plays a relatively larger role in ATP consumption during hypoxia/hypoglycemia than Ca2+ influx. In addition, the anoxic depolarization imposes a large and rapid drop in ATP levels.
Adenosine Triphosphate↗
Rorschach correlates of the DSM-IV histrionic personality disorder.
Rorschach assessment data have long been rationally linked to the psychiatric condition of hysteria. This study represents the first empirical attempt to explore the associations among select Rorschach variables, the Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV]; American Psychiatric Association, 1994) Histrionic Personality Disorder (HPD) criteria, and two self-report measures of hysteria. We correlated four Rorschach variables with total symptom scores for DSM-IV Cluster B Personality Disorders (Borderline, Antisocial, Narcissistic, and Histrionic). We found two Rorschach variables, FC + CF + C and T (Exner, 1993), to be significantly and meaningfully correlated with both the DSM-IV HPD total score (number of criteria) and the individual HPD criteria. Although not significantly associated with the HPD total score, Denial (DEN; Lerner & Lerner, 1980) was associated with one individual HPD criterion. Furthermore, DEN was significantly correlated with the MMPI-2 Hysteria (Hy) scale. The results are reviewed in terms of their clinical utility and the insights they offer into the psychological characteristics of the DSM-IV HPD.
Adult↗
The Rorschach Schizophrenia Index (SCZI): an examination of reliability, validity, and diagnostic efficiency.
In this study, we investigate the reliability, validity, and diagnostic efficiency of the Rorschach Schizophrenia Index (SCZI) in relation to the accurate identification of patients diagnosed with Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV], American Psychiatric Association, 1994) schizophrenia or other psychotic disorder (PD) according to the methodological recommendations offered by Wood, Nezworski, and Stejskal (1996). Seventy-eight patients who were found to meet DSM-IV criteria for a PD or Axis II disorder (PD = 33; borderline personality disorder = 23; Cluster A personality disorders = 9; Cluster C personality disorders = 13) and 50 nonclinical participants were compared on the SCZI. The results of this study indicate that the SCZI is internally consistent and can be reliably scored. In addition, the SCZI was used effectively in differentiating PD patients from patients with an Axis II disorder and from the participants in the nonclinical sample. Also, the SCZI variable was found to be empirically related to the presence of a DSM-IV diagnosis of PD. Finally, this variable could be employed for classification purposes in ways that were clinically meaningful in the diagnosis of a PD. Conceptual and methodological issues are discussed in relation to the assessment of psychosis.
Adult↗
Hydrogen peroxide opposes the hypoxic depression of evoked synaptic transmission in rat hippocampal slices.
Hydrogen peroxide (H2O2, 3.3 mM) partially reversed the hypoxic depression of the evoked population spike recorded from CA1 region of rat hippocampal slices. It is known that elevated endogenous adenosine contributes to the hypoxic inhibition of the population spike. Exogenous adenosine (100 microM) inhibited the population spike that had been partially resuscitated by H2O2 during maintained hypoxia. It is concluded that the ability of H2O2 to oppose hypoxic depression does not occur at the level of the adenosine receptor since added adenosine was still effective in inhibiting the evoked potential in the presence of H2O2.
Adenosine↗
Phorbol ester alters rat hippocampal neuronal response to hypoxia.
The effect of the protein kinase C (PKC) activator, 4 beta-phorbol-12, 13-dibutyrate (beta-PDBu) on electrophysiological properties of rat hippocampal CA1 neurons exposed to moderate hypoxia was examined. Hypoxic beta-PDBu-pretreated neurons differed from untreated neurons by exhibiting an adenosine-independent loss of synaptic transmission, an apparent large increase in injected threshold current necessary to elicit an action potential, an increase rather than a decrease in membrane resistance, and an increase rather than a decrease in hyperpolarizing holding current. Additional experiments with an adenosine A1 antagonist suggest that beta-PDBu alters neuronal responses to hypoxia through some mechanism other than the documented ability of beta-PDBu to uncouple the A1 receptor.
Action Potentials↗
Choline substitution for sodium triggers glutamate and adenosine release from rat hippocampal slices.
Substituting choline for sodium resulted in an extracellularly recorded transient depolarization and increased efflux of glutamate and adenosine from rat hippocampal slices. The depolarization was blocked by a combination of NMDA and non-NMDA antagonists, MK-801 (10 microM) and 6,7-dinitroquinoxaline-2,3-dione (DNQX, 50 microM). Adenosine release was blocked by MK-801 alone. These data suggest that glutamate released as a result of the sodium removal acts at NMDA and non-NMDA glutamate receptors to trigger the depolarization and acts at NMDA receptors to trigger adenosine release.
Adenosine↗
Phorbol ester alters the electrophysiological responses to hypoxia and ischemic-like conditions in the rat hippocampal slice.
The effect of incubation with the protein kinase C activator, 4 beta-phorbol 12,13-dibutyrate (beta-PDBu) on the electrophysiological responses to hypoxia and combined hypoxia and hypoglycemia was investigated in the rat hippocampal slice. Preincubation with beta-PDBu prevents adenosine-mediated inhibition of synaptic transmission under normoxic, normoglycemic conditions. beta-PDBu preincubation also reduces the adenosine-mediated hypoxia-induced depression of synaptic transmission revealing a substantial adenosine-independent hypoxia-induced depression of synaptic transmission. During combined hypoxia and hypoglycemia, slices preincubated in beta-PDBu display a significant shortening of the time of anoxic depolarization, an effect of beta-PDBu that is not mimicked by application of the adenosine antagonist cyclopentyltheophylline (8-CPT). It is concluded that the state of PKC activation may influence the electrophysiological responses to hypoxia and ischemia.
Action Potentials↗
An evaluation of sequence tagged microsatellite site markers for genetic analysis within Citrus and related species.
Microsatellites, also called sequence tagged microsatellite sites (STMSs), have become important markers for genome analysis but are currently little studied in plants. To assess the value of STMSs for analysis within the Citrus plant species, two example STMSs were isolated from an intergeneric cross between rangpur lime (Citrus x limonia Osbeck) and trifoliate orange (Poncirus trifoliata (L.) Raf.). Unique flanking primers were constructed for polymerase chain reaction amplification both within the test cross and across a broad range of citrus and related species. Both loci showed length variation between test cross parents with alleles segregating in a Mendelian fashion to progeny. Amplification across species showed the STMS flanking primers to be conserved in every genome tested. The traits of polymorphism, inheritance, and conservation across species mean that STMS markers are ideal for genome mapping within Citrus, which contains high levels of genetic variability.
Alleles↗
Enrichment of microsatellites from the citrus genome using biotinylated oligonucleotide sequences bound to streptavidin-coated magnetic particles.
A method is described for the rapid isolation of microsatellite sequences using a biotin-labeled oligonucleotide attached to streptavidin-coated magnetic particles. The oligonucleotide "hook" in solution hybridizes to complementary single-stranded lengths of genomic DNA onto which have been engineered specific PCR priming sites. The final product is an enriched library of microsatellites of defined sequences. The method is applicable to any genome and in principle is adaptable to the rapid isolation of both repetitive as well as genic sequences. It is illustrated by the isolation of trinucleotide repeat (TAA)n sequences from the citrus genome.
Bacterial Proteins↗
PCR amplification of alleles at locus D17S5: detection of new and rare long-length alleles by oligoprobing in a survey of Australian populations.
Alleles of the hypervariable human locus D17S5 were amplified by polymerase chain reaction (PCR) and categorized by length. Unlike other surveys of this locus, the products of amplification were authenticated by Southern analysis using an oligomeric probe directed to part of the 70-base-pair (bp) variable number of tandem repeat (VNTR) region. A small number of unusually long alleles were located. In a survey of 201 unrelated Caucasian individuals, 16 alleles (size range, 170-1430 bp) and 59 genotypes were observed (heterozygosity, 86.4%; discriminating power, 0.963). In a similar survey of 166 traditional Australian aboriginals, 18 alleles (size range, 170-1430 bp) and 46 genotypes were found (heterozygosity, 80.8%; discriminating power, 0.942). The allele frequencies differed significantly between these two ethnically distinct populations. Comparisons are made with other anthropologically diverse populations.
Alleles↗
Purine release and inhibition of synaptic transmission during hypoxia and hypoglycemia in rat hippocampal slices.
Evoked synaptic potentials and purine efflux were measured simultaneously from rat hippocampal slices. Slices were exposed to hypoxia, to glucose-free medium, and to in vitro ischemia consisting of glucose-free, hypoxic medium. During exposure to hypoxia or the glucose-free condition, radiolabelled purine efflux increased and the evoked population spike declined. Synaptic potentials and purine efflux returned to baseline values after reintroduction of normoxic and normoglycemic medium. During exposure to in vitro ischemia, purine and adenosine efflux were greatly increased with the appearance of the anoxic depolarization.
Adenine↗
Changes in extracellular adenosine levels and population spike amplitude during graded hypoxia in the rat hippocampal slice.
Concentrations of adenosine and inosine in the incubation media of baths containing rat hippocampal slices were measured during graded hypoxia. Slices were exposed to atmospheres containing 95%, 71%, 48%, 24%, or 0% oxygen, with 5% CO2 and a balance of N2. Absorbance HPLC measurements were made with samples drawn from static tissue baths each containing four slices supported on a net at the interface between the medium and the atmosphere. Concentrations of adenosine and inosine were proportionate to the fractional oxygen content. They were significantly higher in atmospheres of 24% and 0% O2. Introducing a 95% N2/5% O2 atmosphere in place of 95% O2/5% CO2 resulted in a roughly 4-fold increase in the adenosine concentration in the bath. The adenosine transport blocker dipyridamole (200 microM), and the convulsant drug picrotoxinin (300 microM), had little effect on basal levels of adenosine measured at 95% O2 but significantly augmented the responses seen at 48%, 24% and 0% O2. Picrotoxinin, while increasing the adenosine concentration did not change the ratio of adenosine to inosine. In contrast, dipyridamole significantly increased the ratio of adenosine to inosine. Evoked population spikes were recorded from the CA1 layer. The population spike amplitude was depressed as the fractional oxygen content was reduced. It is concluded that adenosine regulation in the slice preparation is similar to that seen in the intact animal. In particular, the amounts of adenosine released into the incubation medium are related to oxygen availability.
Action Potentials↗
Glucose deprivation results in a lactate preventable increase in adenosine and depression of synaptic transmission in rat hippocampal slices.
The effect of glucose deprivation on adenosine levels and on synaptic transmission was investigated in rat hippocampal slices. Incubation of hippocampal slices either in glucose-free medium or in the presence of the glucose transport inhibitor cytochalasin B (50 microM) increased bath adenosine levels and depressed the extracellularly recorded synaptic potential or population spike. The addition of lactate (10 mM), a precursor for mitochondrial ATP generation, prevented the elevation in adenosine and the depression of the population spike. These results indicate that the neuroinhibitory modulator adenosine is elevated during glucose deprivation and contributes to the hypoglycemic depression of synaptic transmission. The increase in adenosine during glucose deprivation can be prevented by providing substrate for mitochondrial ATP generation. The present results indicate an interaction between lactate and adenosine such that an increase in lactate may contribute to a decline in adenosine production.
Adenosine↗
Escape from inhibition of synaptic transmission during in vitro hypoxia and hypoglycemia in the hippocampus.
Electrophysiological recordings were made from rat hippocampal slices exposed to in vitro ischemic conditions in which the superfused medium is hypoxic and lacking glucose. Under these conditions, the evoked population spike recorded in CA1 is initially depressed and then transiently returns prior to an anoxic depolarization. This transient return in synaptic function under ischemic-like conditions also occurs if the population spike is inhibited by pretreatment with adenosinergic agonists or with the gamma-aminobutyric acid (GABA)B agonist, baclofen.
Adenosine↗
Satellite III DNA: regions of extreme endonuclease resistance and inter-individual polymorphism in the Mb size range.
Southern analysis of within-gel digested and restricted human cells has revealed very large Satellite III restriction fragments which show clear inter-individual length polymorphism. The Mb and sub-Mb length of these fragments indicate that they arise from regions of heterochromatin which contain homogeneous Satellite III sequences of peculiar resistance to common endonucleases. Based on sequence alone, such regions would be little digested by endonuclease digestion of chromatin in metaphase, regardless of its method of preparation. Polymorphic regions such as these might be expected to stain as part of the C-banding seen in endonuclease treated metaphase chromosomes, and may in part account for inter-individual C-band heteromorphisms.
Cells, Cultured↗
Analysis of mixed human/microbial DNA samples: a validation study of two PCR AMP-FLP typing methods.
The reliability of the PCR technique used to type two human variable number tandem repeats, that is, 3' to apolipoprotein B gene and locus D17S30, was examined using DNA samples of mixed human and microbial origin. Mixtures of human and microbial DNA were amplified, choosing microbes found commonly in the vagina. Total inhibition of human amplification and/or "drop-out" of the larger amplification fragment length polymorphism allele was observed at both loci in the presence of DNA from some vaginal micro-flora.
Artifacts↗
Adenosine antagonists alter the synaptic response to in vitro ischemia in the rat hippocampus.
Exposure of the submerged hippocampal slice to in vitro ischemic conditions (superfusion with hypoxic medium lacking glucose) resulted in a progression of changes in the orthodromically evoked response recorded from the CA1 pyramidal region. There was an early depression of the population spike with no change in the presynaptic fiber volley, followed by a transient return of the population spike and, finally, a complete loss of both the population spike and fiber volley. The adenosine A1 subtype-selective antagonists, 8-phenyltheophylline (8-PT) and 8-cyclopentyltheophylline (8-CPT), greatly attenuated the early depression of the population spike such that the initial loss of the population spike was associated with the loss of the fiber volley. This result suggests that the initial loss of synaptic function in the hippocampal slice during exposure to in vitro ischemic conditions is due to increased levels of the inhibitory neuromodulator, adenosine.
Action Potentials↗