Sodium channel inhibition by anandamide and synthetic cannabimimetics in brain

Anandamide is a prominent member of the endocannabinoids, a group of diffusible lipid molecules which influences neuronal excitability. In this context, endocannabinoids are known to modulate certain presynaptic Ca(2+) and K(+) channels, either through cannabinoid (CB1) receptor stimulation and second messenger pathway activation or by direct action. We investigated the susceptibility of voltage-sensitive sodium channels to anandamide and other cannibimimetics using both biochemical and electrophysiological approaches. Here we report that anandamide, AM 404 and WIN 55,212-2 inhibit veratridine-dependent depolarization of synaptoneurosomes (IC(50)s, respectively 21.8, 9.3 and 21.1 microM) and veratridine-dependent release of L-glutamic acid and GABA from purified synaptosomes [IC(50)s: 5.1 microM (L-glu) and 16.5 microM (GABA) for anandamide; 1.6 microM (L-glu) and 3.3 microM (GABA) for AM 404, and 12.2 (L-glu) and 14.4 microM (GABA) for WIN 55,212-2]. The binding of [3H]batrachotoxinin A 20-alpha-benzoate to voltage-sensitive sodium channels was also inhibited by low to mid micromolar concentrations of anandamide, AM 404 and WIN 55,212-2. In addition, anandamide (10 microM), AM 404 (10 microM) and WIN 55,212-2 (1 microM) were found to markedly block TTX-sensitive sustained repetitive firing in cortical neurones without altering primary spikes, consistent with a state-dependent mechanism. None of the inhibitory effects we demonstrate on voltage-sensitive sodium channels are attenuated by the potent CB1 antagonist AM 251 (1-2 microM). Anandamide's action is reversible and its effects are enhanced by fatty acid amidohydrolase inhibition. We propose that voltage-sensitive sodium channels may participate in a novel signaling pathway involving anandamide. This mechanism has potential to depress synaptic transmission in brain by damping neuronal capacity to support action potentials and reducing evoked release of both excitatory and inhibitory transmitters.

Use of a habit reversal treatment for temporomandibular pain in a minimal therapist contact format

Previous research has suggested that a habit reversal treatment might be used effectively in a home-based minimal therapist contact (MTC) protocol to facilitate flexibility and increase treatment completion rates. Recent reviews of MTC interventions have found it to be generally efficacious, cost-effective, and generalizable. While MTC has been used for certain health-related disorders (e.g., headache), almost no research has evaluated the effectiveness of a MTC protocol with a population suffering from temporomandibular disorder (TMD). The current study utilized an oral habit reversal treatment in a MTC format in an attempt to reduce attrition and increase treatment flexibility. Twenty females suffering from TMD were randomly assigned to either a treatment (n = 10) or a wait-list control (n = 10) condition. Six individuals in each group used telephone contact while 4 used e-mail for weekly communication with the therapist. Results demonstrated that a habit reversal treatment in a MTC format led to statistically and clinically significant improvements in mean weekly pain ratings, number of pain-free days per week, and highest weekly pain ratings. Also, a significant reduction in maladaptive oral habits occurred from pre- to post-treatment and significant reductions in life stress and pain interference were observed. Results were maintained at follow-up. The implications for the use of MTC for treatment of facial pain are discussed, as are the implications of these findings for the role of oral habits in the etiology of TMD.

Insecticidal arylalkylbenzhydrolpiperidines: novel inhibitors of voltage-sensitive sodium and calcium channels in mammalian brain

Using preparations derived from whole mouse brain, we have demonstrated that insecticidal arylalkylbenzhydrolpiperidines inhibit the depolarization of synaptoneurosomes as measured by rhodamine 6G fluorescence and block 22Na+ uptake into synaptosomes, when veratridine is used as the activator. These insecticides also have the ability to potently displace the binding of [3H]batrachotoxinin A 20-alpha-benzoate ([3H]BTX-B) to neuronal sodium channels in a concentration-dependent manner. The study compounds can be classified as competitive inhibitors of radioligand binding, since they decrease the affinity of [3H]BTX-B for site 2 without affecting the concentration of sites labelled by this radioligand. Our kinetic analyses revealed that at its IC50, the 4-carbomethoxyaminobenzyl-piperidine analogue reduces the rate of association of [3H]BTX-B with site 2, whereas higher concentrations were required to accelerate dissociation of the [3H]BTX-B:sodium channel complex. These results indicate an ability to interact with both non-activated and persistently activated states of the voltage-sensitive sodium channel, but higher affinity for the former. Such a profile also implies that inhibition of [3H]BTX-B binding to site 2 occurs via an allosteric mechanism. In addition, arylalkylbenzhydrolpiperidines interact with presynaptic voltage-sensitive calcium channels, since we demonstrate that they inhibit increases in [free Ca++] and 45Ca++ uptake when evoked by high KC1 concentration in mouse brain synaptosomal preparations. Such effects generally occur at concentrations that are higher than those required to inhibit sodium channels. Blockade of sodium and calcium channels may therefore contribute to the in vivo neurological effects observed in rodents exposed to these insecticides.

RH-3421 action and toxicokinetics in the trout: reduced brain involvement versus mammals

The action and distribution of the insecticidal dihydropyrazole RH-3421 was examined in the trout and mouse. RH-3421 antagonized the depolarizing effect of the Na(+) channel activator veratridine and inhibited K(+)-stimulated uptake of (45)Ca(++) through voltage-sensitive calcium channels in trout brain synaptosomes. RH-3421 was a weaker inhibitor of these cellular targets in fish brain compared to mammalian brain. [(14)C]RH-3421 distributed rapidly following systemic administration to trout. Trunk kidney, muscle, liver and fat are important sites of accumulation, however, accumulation of [(14)C]RH-3421 in trout brain was low and polar metabolites were only found in bile. Mice administered an equivalent dose accumulated [(14)C]RH-3421 more efficiently into brain, and overall metabolism was more extensive. In trout, the brain is unlikely to be a major site of action of dihydropyrazoles. Our data indicate that perturbation of neuronal sites outside of brain cannot be excluded as contributing to the comparatively high acute toxicity of dihydropyrazoles in fish.

Anesthetic-like interaction of the sleep-inducing lipid oleamide with voltage-gated sodium channels in mammalian brain

BACKGROUND

cis-9,10-Octadecenoamide (cOA) accumulates in cerebrospinal fluid during sleep deprivation and induces sleep in animals, but its cellular actions are poorly characterized. In earlier studies, like a variety of anesthetics, cOA modulated gamma-aminobutyric acidA receptors and inhibited transmitter release/burst firing in cultured neurones or synaptoneurosomes.

METHODS

Here, radioligand binding ([3H]batrachotoxinin A 20-alpha-benzoate and mouse central nervous system synaptoneurosomes) and voltage clamp (whole cell recording from cultured NIE115 murine neuroblastoma) confirmed an interaction with neuronal voltage-gated sodium channels (VGSC).

RESULTS

cOA stereoselectively inhibited specific binding of toxin to VGSC (inhibitor concentration that displaces 50% of specifically bound radioligand, 39.5 microm). cOA increased (4x) the Kd of toxin binding without affecting its binding maximum. Rate of dissociation of radioligand was increased without altering association kinetics, suggesting an allosteric effect (indirect competition at site 2 on VGSC). cOA blocked tetrodotoxin-sensitive sodium currents (maximal effect and affinity were significantly greater at depolarized potentials; P < 0.01). Between 3.2 and 64 microm, the block was concentration-dependent and saturable, but cOA did not alter the V50 for activation curves or the measured reversal potential (P > 0.05). Inactivation curves were significantly shifted in the hyperpolarizing direction by cOA (maximum, -15.4 +/- 0.9 mV at 32 microm). cOA (10 microm) slowed recovery from inactivation, with tau increasing from 3.7 +/- 0.4 ms to 6.4 +/- 0.5 ms (P < 0.001). cOA did not produce frequency-dependent facilitation of block (up to 10 Hz).

CONCLUSIONS

These effects (and the capacity of oleamide to modulate gamma-aminobutyric acidA receptors in earlier studies) are strikingly similar to those of a variety of anesthetics. Oleamide may represent an endogenous ligand for depressant drug sites in mammalian brain.

Influence of a scheduled-waiting task on EMG reactivity and oral habits among facial pain patients and no-pain controls

Recent research has strongly implicated the role of psychological stress in the development of temporomandibular disorders (TMD). It is widely reported that oral habits (e.g., teeth grinding) probably provide a behavioral link between stress and the development of TMD symptomatology. Extrapolation of research in the field of adjunctive behavior to the TMD disorders suggests that oral behaviors may develop conjointly with fixed-time (FT) stimulus presentation. The current experiment extended previous research examining this possibility by assessing the influence of experimental stress on masseter EMG and oral habits among persons who met broadband criteria for TMD and no-pain controls. Oral habit activity was assessed via self-report questionnaire whereas masseter muscle activity was measured continuously via electromyography across four phases (Adaptation, Free-Play, Scheduled-Play, Recovery). The Scheduled-Play phase was designed as a stress-reactivity task that included an FT schedule. Results indicated that, consistent with the stress-reactivity model, the Scheduled-Play phase resulted in a significant increase in masseter EMG levels relative to Free-Play and Adaptation, and that this effect was significantly larger for the TMD group relative to controls. The results suggest an adjunctive behavior effect although the effect was not specific to those with facial pain. Oral habit data showed a significant phase effect with oral habits that was significantly higher during the Scheduled-Play phase relative to Adaptation. The findings are the impetus for further study regarding the mechanisms whereby oral habits are developed and maintained despite their painful consequences.

Fentanyl self-administration in juvenile rats that were tolerant and dependent to fentanyl as infants

Human neonates and infants can become tolerant and dependent during continuous fentanyl or morphine administration. The long-term consequences in these individuals as juveniles and adults are unknown. This study compared fentanyl self-administration behavior in juvenile rats that were opioid naive or were exposed chronically to fentanyl as infants. Postnatal day 14 infant rats remained naive or were implanted with saline- or fentanyl-filled Alzet minipumps. After 72 h, fentanyl's antinociceptive potency was 3.0-fold lower in the fentanyl-infused rats. Naloxone precipitated withdrawal occurred only in the fentanyl-infused animals. Other similarly treated infant rats were allowed to mature into P42 juvenile rats before enrolling them in an oral fentanyl self-administration study. Rats from each group consumed significantly more fentanyl than quinine. However, those rats, tolerant and dependent to fentanyl as infants, did not self-administer more fentanyl than their opiate-naive littermates. The issue of whether fentanyl was consumed for its reinforcing properties was demonstrated when noncontingent administration of opiate antagonists significantly reduced fentanyl intake in another group of juvenile rats. These data indicate that fentanyl is consumed for its reinforcing properties, but that infant fentanyl tolerance and dependence did not predispose them to self-administer more fentanyl than opiate-naive animals.

Can the MMPI-2 validity scales detect depression feigned by experts?

Major depression is one of the most frequently presented disorders for claims of psychiatric disability. Evidence also suggests that many individuals making claims of disability exaggerate or even fabricate mental illness. These facts suggest that the detection of feigned depression is an important task in psychiatric disability claim assessments. In this study, the capacity of a number of MMPI-2 validity scales and indicators to detect feigned depression was examined. Twenty-three mental health professionals with specific expertise and significant experience in assessing and treating major depression were asked to complete the MMPI-2 as if they were suffering from major depression. The MMPI-2 protocols of this sample were compared to those of a sample of patients diagnosed with major depression. Results indicated that the validity scales F, back F (FB), and the Dissimulation scale (Ds) were highly successful at distinguishing MMPI-2 protocols of feigned depression from bona fide depression. Replicating results from previous studies, however, FB proved most effective, outperforming all other validity scales and indicators, including F and Ds. These findings suggest that even experts are unable to feign major depression successfully on the MMPI-2, and that the FB scale might be the most effective indicator for detecting feigned depression.

The quality of forensic psychological assessments, reports, and testimony: acknowledging the gap between promise and practice

During the past decade, the field of forensic psychological assessment entered a period of standard setting, reflected in the publication of specialty guidelines for practice and in the proliferation of educational opportunities, training programs, and credentialing and certification procedures for forensic examiners. Representing significant efforts to advance the quality of psychological assessments in legal contexts, these developments foreshadow the promise of forensic assessment. During this same time period, new evidence emerged regarding the quality of forensic practice. This article reviews this evidence and evaluates current practice against the promise of forensic assessment. Forensic reports appear to be of higher quality than those described by commentators in the 1970s and early 1980s; nevertheless, the level of practice falls far short of professional aspirations for the field. The review identifies significant areas of weakness that demand the attention of professional organizations, accrediting agencies, educators, lawmakers, practitioners, and consumers.

Stereoselective modulatory actions of oleamide on GABA(A) receptors and voltage-gated Na(+) channels in vitro: a putative endogenous ligand for depressant drug sites in CNS

1. cis-9,10-octadecenoamide ('oleamide') accumulates in CSF on sleep deprivation. It induces sleep in animals (the trans form is inactive) but its cellular actions are poorly characterized. We have used electrophysiology in cultures from embryonic rat cortex and biochemical studies in mouse nerve preparations to address these issues. 2. Twenty microM cis-oleamide (but not trans) reversibly enhanced GABA(A) currents and depressed the frequency of spontaneous excitatory and inhibitory synaptic activity in cultured networks. 3. cis-oleamide stereoselectively blocked veratridine-induced (but not K(+)-induced) depolarisation of mouse synaptoneurosomes (IC(50), 13. 9 microM). 4. The cis isomer stereoselectively blocked veratridine-induced (but not K(+)-induced) [(3)H]-GABA release from mouse synaptosomes (IC(50), 4.6 microM). 5. At 20 microM cis-oleamide, but not trans, produced a marked inhibition of Na(+) channel-dependent rises in intrasynaptosomal Ca(2+). 6. The physiological significance of these observations was examined by isolating Na(+) spikes in cultured pyramidal neurones. Sixty-four microM cis-oleamide did not significantly alter the amplitude, rate of rise or duration of unitary action potentials (1 Hz). 7. cis-Oleamide stereoselectively suppressed sustained repetitive firing (SRF) in these cells with an EC(50) of 4.1 microM suggesting a frequency- or state-dependent block of voltage-gated Na(+) channels. 8. Oleamide is a stereoselective modulator of both postsynaptic GABA(A) receptors and presynaptic or somatic voltage-gated Na(+) channels which are crucial for synaptic inhibition and conduction. The modulatory actions are strikingly similar to those displayed by sedative or anticonvulsant barbiturates and a variety of general anaesthetics. 9. Oleamide may represent an endogenous modulator for drug receptors and an important regulator of arousal.

EMG reactivity and oral habits among facial pain patients in a scheduled-waiting competitive task

For individuals with temporomandibular disorder (TMD) it has been theorized that stressful events trigger oral habits (e.g., teeth grinding), thereby increasing masticatory muscle tension and subsequent pain. Recent research involving adjunctive behaviors found an increase in masseter surface EMG (sEMG) and oral habits when students with TMD symptomatology were placed on a fixed-time reinforcement schedule. The current study used a treatment-seeking community sample with TMD symptomatology in a competitive task designed to be a more naturalistic Fixed Time task. The experiment consisted of Adaptation, Free-Play, Scheduled-Play, and Recovery phases. During the Scheduled-Play phase participants played, and waited to play, an electronic poker game. Results indicated that masseter muscle tension in the Scheduled-Play phase was significantly higher (p < .001) than in any other phase. Moreover, during the Scheduled-Play phase masseter sEMG was higher (p < .001) when participants waited to play. Self-reported oral habits and overall affect were significantly higher (p's < .05) in the Free-Play and Scheduled-Play phases relative to Adaptation and Recovery. The observation that masseter sEMG was elevated during the Scheduled-Play phase relative to all other phases, and within the Scheduled-Play phase sEMG was highest while waiting, suggests that adjunctive oral habits may lead to TMD symptomatology.

Effects of state organizational structure and forensic examiner training on pretrial competence assessments

States differ widely in their delivery of pretrial forensic evaluation services, in terms of organizational structure and training requirements of forensic examiners. It was hypothesized that defendants adjudicated incompetent to proceed in states using community-based, private-practitioner systems would show less impairment on a competence assessment measure, the MacArthur Competence Assessment Tool-Criminal Adjudication (MacCAT-CA), than defendants adjudicated incompetent in states using traditional, inpatient systems. It also was hypothesized that mean MacCAT-CA scores for incompetent defendants from states requiring forensic training/certification would be lower than for defendants from states lacking such requirements. Results indicated significant differences across the four types of service delivery systems examined. However, planned comparisons revealed no differences between a state using a traditional, inpatient model and a state employing a community-based, private-practitioner model. Analyses examining the effects of mandatory forensic training failed to support the hypothesis that training requirements result in the adoption of higher thresholds for determining incompetence.

Inhibition of GABA-gated chloride channels by 12,14-dichlorodehydroabietic acid in mammalian brain

1. 12,14-dichlorodehydroabietic acid (12,14-Cl2DHA) reduced GABA-stimulated uptake of 36Cl- into mouse brain synaptoneurosomes suggesting inhibition of mammalian GABA(A) receptor function. 2. 12,14-Cl2DHA did not affect the binding of [3H]-muscimol to brain membranes but displaced specifically bound [3H]-EBOB. The inhibitory effect on [3H]-EBOB binding was not reversible. 12,14-Cl2DHA reduced the availability of [3H]-EBOB binding sites (Bmax) without changing the KD of the radioligand for remaining sites. 12,14-Cl2DHA did not affect the rate of association of [3H]-EBOB with its chloride channel receptor, but increased the initial rate of [3H]-EBOB dissociation. 3. 12,14-Cl2DHA enhanced the incidence of EPSCs when rapidly applied to cultured rat cortical neurones. Longer exposures produced block of IPSCs with marked increases in the frequency of EPSCs and min EPSCs. 12,14-Cl2DHA also irreversibly suppressed chloride currents evoked by pulses of exogenous GABA in these cells. 4. Ultimately, 12,14-Cl2DHA inhibited all synaptic traffic and action currents in current clamped cells indicating that, in contrast to picrotoxinin (which causes paroxysmal bursting), it is not fully selective for the GABA(A) receptor-chloride channel complex. 5. The depolarizing block seen with 12,14-Cl2DHA in amphotericin-perforated preparations implicates loss of Ca2+ buffering in the polarity change and this may account for inhibition of spontaneous action potentials. 6. Our investigation demonstrates that 12,14-Cl2DHA blocks GABA-dependent chloride entry in mammalian brain and operates as a non-competitive insurmountable GABA(A) antagonist. The mechanism likely involves either irreversible binding of 12,14-Cl2DHA to the trioxabicyclooctane recognition site or a site that is allosterically coupled to it. We cannot exclude, however, the possibility that 12,14-Cl2DHA causes localized proteolysis or more extensive conformational change within a critical subunit of the chloride channel.

Cristobalite in volcanic ash of the soufriere hills volcano, montserrat, british west indies

Crystalline silica (mostly cristobalite) was produced by vapor-phase crystallization and devitrification in the andesite lava dome of the Soufriere Hills volcano, Montserrat. The sub-10-micrometer fraction of ash generated by pyroclastic flows formed by lava dome collapse contains 10 to 24 weight percent crystalline silica, an enrichment of 2 to 5 relative to the magma caused by selective crushing of the groundmass. The sub-10-micrometer fraction of ash generated by explosive eruptions has much lower contents (3 to 6 percent) of crystalline silica. High levels of cristobalite in respirable ash raise concerns about adverse health effects of long-term human exposure to ash from lava dome eruptions.

Dangerousness and disability as predictors of psychiatric patients' legal status

In a sample of patients admitted to two state psychiatric facilities, discriminant analyses were used to predict (1) legal status at admission (voluntary versus emergency detention), and (2) the subsequent decision to commit patients initially admitted under an order of emergency detention (court commitment versus release). Measures of preadmission dangerousness, followed by variables reflecting degree of disability or impairment, accounted for most of the variance in legal status at admission. Personal resources and demographic characteristics added little to the discrimination. Measures of disability accounted for most of the variance in the later decision to commit, whereas indices of dangerousness, personal resources, and demographics added little to discrimination of discharged and court-committed patients. These findings reflect the gap between legal standards and the practice of civil commitment, and support the argument that degree of disability plays a more important role than dangerousness in decisions to extend the hospitalization of involuntary patients.

Role of psychosocial treatments in management of schizophrenia: a meta-analytic review of controlled outcome studies

This meta-analytic review sought to answer questions concerning the role of psychosocial treatments in the comprehensive management of patients with schizophrenia. The review focused on the effects of combining psychosocial treatment with somatic treatment. Findings demonstrated the additive and supplementary effects of psychosocial treatments and the durability of these effects. Patients with more chronic illness appeared to be more responsive to psychosocial treatments, as were patients in studies conducted in non-Western countries. Among the Western countries, studies from Scandinavian countries reported the least effectiveness for psychosocial treatments. There was some evidence for differential effect of psychosocial treatments on different dimensions of illness as the measures of disorganized behavior and employment showed little difference in treated and control groups. There was also some evidence for differences between different modalities of treatment as group treatments produced smaller effects. Implications for practice and future research are discussed.

Benzo(a)pyrene toxicokinetics in the cricket following injection into the haemolymph

The metabolic disposition of (14)C-labelled benzo(a)pyrene (BP) in the cricket (Acheta domesticus) was investigated after injection into the haemolymph. (14)C-BP was taken up rapidly by the nerve cord, malpighian tubules, reproductive organs, gut, and muscle:cuticle of the cricket. The elimination half-lives of (14)C-BP in these tissues ranged from 8.9 to 17.8 h. The haemolymph (14)C-BP concentration-time curve could be described by a one-compartment open pharmacokinetic model. (14)C-BP was metabolized by the cricket mainly to unconjugated and conjugated BP metabolites since very little unchanged (14)C-BP was found in the excreta at 48 h post-dosing. GLPC-MSD and HPLC/ES-MS analyses showed the presence of at least two BP metabolites in the excreta. The BP metabolites were identified tenatively as the diol derivatives of benzo(a)pyrene and benzo(a)pyrene quinone.

Inhibition of respiratory and bioenergetic mechanisms by hydrogen sulfide in mammalian brain

The biochemical effects of hydrogen sulfide were investigated by treating enzyme homogenates and synaptosomes prepared from mammalian brain with sodium sulfide. Brain cytochrome c oxidase activity was highly sensitive to inhibition by sodium sulfide, as demonstrated by an IC50 of 0.13 microM. Sodium sulfide was also found to inhibit carbonic anhydrase activity in cerebellum, frontal cortex, and hippocampus. Synaptosomal oxygen consumption was significantly reduced as the concentration of sodium sulfide was increased from 20 to 100 microM; this was accompanied by a concentration-dependent depolarization of the synaptosomal mitochondrial membrane in situ and a reduction in synaptosomal ATP concentration. In other experiments using synaptosomes, sodium sulfide caused a significant calcium-independent increase in the extracellular accumulation of L-glutamate, inhibited Na+-dependent uptake of [3H]glutamate, but was unable to influence intrasynaptosomal free ionic Ca2+. Parallel studies conducted in vivo showed that rats exposed over a 5-d period to hydrogen sulfide (100 ppm for 3 h/d) had significantly higher concentrations of L-glutamate in the hippocampus compared to control animals. In summary, our results indicate that sulfide causes extensive disruption to respiratory and related mitochondrial functions in mammalian brain in vitro. The reduced capacity of nerve endings to take up L-glutamate may contribute to the raised L-glutamate levels observed in vivo.

Detecting feigned depression and schizophrenia on the MMPI-2

Increasingly, investigations evaluating the effectiveness of the MMPI-2 in the assessment of malingering employ methodologies whereby research participants are asked to feigned specific disorders rather than just to "fake bad." Yet there is little research addressing the issue of whether different validity scales and indicators work differently in the detection of different feigned disorders. In this study the comparative effectiveness of a number of validity scales and indicators on the MMPI-2 to assess feigned depression and feigned schizophrenia were evaluated. Overall, the validity scales and indicators were better at detecting feigned schizophrenia than they were in detecting feigned depression, attributable, most likely, to closer familiarity with depressive experiences. The validity scales F, Fb, and F(p) best distinguish patients with schizophrenia from participants feigning schizophrenia, and F and Fb best distinguish patients with depression from participants feigning depression.

Training phantom for ultrasound guided biopsy

Commercial phantoms designed for radiologists to practise the skills needed to biopsy lesions under ultrasound guidance can be prohibitively costly, and do not have an indefinite shelf-life. A gelatin-based in-house model has been developed to recreate the conditions found in human tissues, using materials which are cheap and in everyday use. This phantom remains useful for several weeks, although tears produced by the biopsy needle take progressively longer to bond when the reconstructed gelatin is older than a month. However, new phantoms can be built quickly and easily using fresh gelatin while recycling other components.

Isolation of an enriched fraction of nerve terminals from fish brain using a discontinuous Percoll gradient

A discontinuous gradient of Percoll has been used to prepare a subcellular fraction (fraction III) from fish brain which is greatly enriched in synaptic nerve endings (synaptosomes). Synaptosomes display well-preserved morphology, good functional performance as assessed by ability to release preloaded neurotransmitter following depolarization, and the fraction as a whole has an enzyme profile consistent with the presence of nerve endings. The procedure is rapid, highly reliable and provides a mean yield of 4.5 mg synaptosomes per g wet weight of brain.

Factors affecting relapse in patients discharged from a public hospital: results from survival analysis

This study examined the effects of demographics, personal resources, and psychiatric characteristics on relapse risk in patients discharged from two state facilities. Data on 2,002 first admissions to an Oklahoma state hospital and an associated CMHC during a single year, and information on readmissions of these patients to any of the seven state facilities providing inpatient treatment for an additional two years were collected. Data were analyzed by survival analysis with the Cox regression model. Out of the different demographic, social and psychiatric variables, the patients' diagnosis, length of index hospitalization and level of functioning at discharge as well as interaction of employment status and living status and interaction of age and living status were significantly related to relapse rate. These findings are discussed in the context of previous research.

Interrater reliability of ratings of delusions and bizarre delusions

OBJECTIVE

The authors evaluated the interrater reliability of ratings of bizarre delusions, addressing limitations of previous studies.

METHOD

Fifty randomly selected psychiatrists rated bizarre delusions in 30 case vignettes adapted from a previous study by Spitzer and associates. Estimates of reliability were obtained for definitions of bizarre delusions in the DSM-III, DSM-III-R, and draft DSM-IV criteria for schizophrenia and for the clinicians grouped according to their current and previous experience with psychotic patients.

RESULTS

The kappas for ratings of bizarre delusions according to the different definitions and among clinicians with different levels of experience were in the moderate to fair range.

CONCLUSIONS

The reliability of ratings of bizarre delusions appears to be less than satisfactory for clinical practice, and the increased weight given to this symptom in modern diagnostic systems does not seem justifiable.

Metallothionein expression in human breast cancer

Metallothioneins are ubiquitous low molecular weight proteins characterised by high cysteine content and affinity for binding heavy metals. Abnormal metallothionein function and expression have been implicated in various disease states, including neoplasia. The aim of this study was to investigate metallothionein expression in human breast carcinoma. Sections of routinely fixed and processed blocks of tumour from 100 consecutive cases of primary operable breast carcinoma were stained for metallothionein using a recently developed monoclonal antibody and a standard immunohistochemical technique. Expression was scored on the basis of microscopical assessment of percentage of tumour cells staining. One patient was lost to follow-up and excluded from the study. A significant association (P < 0.0001) was observed between metallothionein expression and tumour type, with low levels being observed in tumours of good prognostic type. There was also a significant association with local recurrence (P < 0.02) and a significant difference (P < 0.02) in both survival and disease-free interval between tumours showing low and high levels of expression, the latter indicating a poor prognosis. No relationship was observed with patient age, tumour size, lymph node stage, histological grade, vascular invasion, menopausal status or oestrogen receptor status. The assessment of metallothionein expression in human breast cancer appears to provide prognostic information and may have important implications for understanding its development.

Technical note: the relationship between TV position and the effectiveness and comfort of protective spectacles in fluoroscopic procedures

Although interventional radiological procedures can result in significant eye doses to an operator, protective measures are often rejected because screens are found to impede manipulations, and 0.5 mm lead equivalent spectacles are heavy and uncomfortable. With many units the TV monitors are positioned so that the operator needs to turn his head through 80 degrees or more to view the image while screening. The aim of this study was to determine the distribution of the shielding in protective spectacles which will combine maximum dose reduction for different TV positions with minimum weight. Thermoluminescent dosimeters were used to assess the effectiveness of various spectacles in shielding the lens of the eye when a skull phantom was orientated at different angles in a large area beam of X-rays generated at a tube potential typical of diagnostic energies. The beam was tilted upwards at an angle of 20 degrees as though originating from the irradiated volume of a patient. The results showed that if weight was a consideration, and the head was turned away from the image intensifier through an angle greater than 80 degrees, the shielding was most effective when concentrated in the side-panels of the spectacles. The shape of the side-panels, however, was critical to the adequate shielding of this radiation.

Radiation dose reduction in paediatric fluoroscopy using added filtration

Studies on a water phantom indicate that the insertion of extra tube filtration combined with the removal of the antiscatter grid can reduce the total energy imparted from paediatric fluoroscopy by a factor of more than four when automatic exposure control is used. The omission of the grid is responsible for up to 40% of the reduction while the addition of 0.7 mm steel filtration is found to account for a further reduction in energy imparted of between 57% and 70%, for depths of water simulating small patients of 6-16 cm thickness. For all contrast paediatric examinations the reduction in image quality was considered to be small and the diagnostic information unimpaired with the filter in place.

Excitatory actions of dehydroabietic acid on mammalian synaptosomes

The presynaptic effects of dehydroabietic acid were investigated using mouse brain synaptosomes as the in vitro model. At concentrations ranging from 10 to 100 microM, dehydroabietic acid depolarises the synaptosomal membrane and causes pronounced release of the neurotransmitters gamma-aminobutyric acid, acetylcholine and L-glutamate. The effects on membrane potential and transmitter release occur predominantly at concentrations below which any lytic actions of this compound can be detected. Dehydroabietic acid-induced depolarisation and release of neurotransmitters are not influenced by tetrodotoxin and are associated with only marginal inhibition of membrane-associated ATPase activity. When synaptosomes are challenged with dehydroabietic acid in calcium-free saline, a partial reduction in the stimulated release of transmitters is observed. These results provide clear evidence that dehydroabietic acid is neuroactive and capable of causing substantial increases in the release of both excitatory and inhibitory neurotransmitter substances. The mechanism which underlies the neuroexcitatory effects of dehydroabietic acid remains to be resolved however it is proposed that release of transmitters from central nerve endings may be a contributory factor in the toxicity of resin acids.

RH-3421, a potent dihydropyrazole insecticide, inhibits depolarization-stimulated rises in free [Ca2+] and 45Ca2+ uptake in mammalian synaptosomes

The dihydropyrazole RH-3421 inhibits veratridine- and K(+)-induced rises in synaptosomal free Ca2+ with IC50s of 0.2 and 1 microM, respectively. The K(+)-induced rise in free synaptosomal Ca2+, which requires external Ca2+, is also blocked by RH-3421 in the presence of tetrodotoxin. The K(+)-stimulated 45Ca2+ uptake by synaptosomes is unaffected by tetrodotoxin, blocked by cobalt ions and inhibited by RH-3421 both alone (IC50 = 11 microM) and in the presence of tetrodotoxin. RH-3421 does not influence the level of free Ca2+ or basal 45Ca2+ uptake in non-depolarized synaptosomes. The results suggest RH-3421 inhibits voltage-sensitive calcium channels in nerve endings.

Predicting treatment outcome for incompetent defendants

This study examined the prediction of outcome in a sample of defendants hospitalized for treatment of incompetency. Defendants' demographic characteristics and scores on 18 scales of the Computer-Assisted Determination of Competency to Proceed instrument (CADCOMP) were used to predict competency restoration and length of stay (LOS). During the period of study, almost 90 percent of the defendants were restored to competency after a mean stay of over 280 days. Demographic characteristics were unrelated to outcome. Several CADCOMP scales, including two scales measuring psycholegal ability and one measuring psychopathology, were correlated with both outcome criteria. Discriminant analysis using the CADCOMP scales accurately classified 76.7 percent of the defendants into short and long stay groups. Although promising, the findings are nevertheless consistent with prior research in suggesting that examiners should exercise caution in providing feedback to the courts concerning competency restoration and the period of time needed for treatment.

Sub-chronic administration of ethanol to mice does not modify the inhibitory effects of dieldrin, abamectin and the dihydropyrazole RH-3421 at their respective sites of action in the nervous system

1. The potential influence of sub-chronic ethanol treatment on the ability of three chemical classes of insecticide to interact with their neuronal sites of action has been investigated in mouse brain. 2. Ethanol administration did not influence the inhibitory effects of either the cyclodiene dieldrin or the avermectin abamectin as determined by inhibition of GABA-stimulated chloride uptake. 3. Likewise there was also no discernable change in the sensitivity of sodium channels to inhibition by dihydropyrazole RH-3421 with sub-chronic ethanol treatment as assessed indirectly using a membrane potential assay. 4. The results of this study indicate that short term dietary exposure to ethanol fails to cause functional changes to the primary target sites of cyclodienes, avermectins and dihydropyrazoles in the mammalian central nervous system.

p53 protein expression in human breast carcinoma: relationship to expression of epidermal growth factor receptor, c-erbB-2 protein overexpression, and oestrogen receptor

The expression of p53 protein, oestrogen receptor protein, epidermal growth factor receptor (EGFR) and overexpression of the c-erbB-2 oncoprotein was examined in a series of 149 primary symptomatic breast carcinomas. Expression of p53 was present in 62 of 146 cases (42.5%) of the invasive carcinoma and one of three cases (33.3%) of ductal carcinoma in situ (DCIS) examined. Statistical associations of tumour oestrogen receptor positivity and lack of p53 protein expression, chi 2 = 19.78 (d.f. = 1), P less than 0.001, positive tumour p53 status and poor tumour grade; chi 2 = 14.1 (d.f. = 2), P less than 0.001, EGFR expression chi 2 = 7.07, (d.f. = 1), P less than 0.01 and tumour c-erbB-2 protein overexpression; chi 2 = 4.61 (d.f. = 1), P = 0.032 were identified. Expression of p53 is rare in invasive lobular carcinoma of classical type (8.3% of cases examined) in contrast to other common types of mammary carcinoma. Non-significant trends of p53 protein expression and increased regional tumour recurrence; chi 2 = 3.20 (d.f. = 1), P = 0.074 and also poorer patient survival; chi 2 = 3.76 (d.f. = 1), P = 0.053 were identified. p53 protein expression is a common event in human breast cancer and is present in both DCIS and invasive mammary carcinoma. Abnormal expression of p53 protein is a feature of both in situ and invasive breast carcinoma, implying that the abnormal p53 protein expression may be implicated in the early stages of mammary carcinoma progression.

Laser onychology

Laser techniques for nail pathology have existed for over a decade. Published reports concerning onychologic techniques and results are growing along with other medical laser literature. In this article, the author has presented techniques with which he and podiatric colleagues at Wenske Laser Center have operational familiarity. Preoperative concerns have been emphasized and potential complications and prevention are discussed. Widely variant results are identified. Laser onychologic procedures are technique intensive. Research is needed, therefore, to identify factors that might lead to technical improvements so that results may be enhanced. Perhaps in the future laser onychology shall exist as a subspecialty to podiatry and dermatology, much as endodontics is to dentistry. It is hoped that this work might contribute in some small way to that development.

Outcome of hospitalization for defendants found incompetent to stand trial

This study assessed the outcome of hospitalization for incompetent criminal defendants admitted to the forensic unit of a state hospital for treatment during a 4-year period. Findings suggested that the overwhelming majority of the defendants were restored to competency. The defendants also showed significant improvement in overall severity of psychopathology during hospitalization. Further, the duration of hospitalization for these defendants was relatively short. Although these results are promising with regard to treatment of incompetent defendants, predicting the outcome of hospitalization for these defendants was problematic. Prediction of competency restoration was precluded because persistent incompetence was so infrequent. Moreover, multiple regression analyses suggested limited predictive ability with regard to defendants' discharge level of functioning or length of hospitalization. These findings are consistent with the view that examiners should exercise caution in making recommendations to the courts concerning treatability of incompetent defendants.

Itemmetric and scale analysis of a new computer-assisted competency assessment instrument (CADCOMP)

Male defendants (n = 99) who had been court ordered to a forensic treatment facility as incompetent to stand trial were tested using the Computer-Assisted Determination of Competency to Proceed (CADCOMP) instrument soon after admission (median days = 15). Shortly thereafter, competency was assessed by a forensic psychiatrist and by a majority decision of three mental health professionals who viewed a videotape of the forensic psychiatrist's interview. From the CADCOMP item pool, 18 scales were constructed on conceptual grounds. Internal consistency analyses revealed that most scales had reasonable item homogeneity and scale reliability. In addition, item and scale analyses, with few exceptions, followed predicted patterns of intercorrelation and association with competency as determined by both criteria. Scales and items measuring serious psychopathology, psycholegal ability, and criminal history demonstrated the strongest associations with competency. These findings suggest that additional research on CADCOMP is warranted. The instrument shows promise for use in forensic research and assessment.

The dopamine and 5-hydroxytryptamine content of locust and cockroach salivary neurones

The salivary glands of the cockroach and locust are innervated primarily from two pairs of motoneurones, designated SN1 and SN2, in the suboesophageal ganglion. Intracellular cobalt fills and subsequent silver intensification were used to reveal the morphology of these cells in both species. Fluorescent microscopy, following treatment of the ganglion with glyoxylic acid, showed that in both species only the SN1 neurones contained catecholamines. A radioenzymatic assay for dopamine, performed on the locust SN1 neurones, confirmed that this catecholamine was present. A radioenzymatic assay for 5-hydroxytryptamine (5-HT), performed on both pairs of salivary neurones in the locust, revealed small quantities of this amine in the SN2 neurones, but no significant amount in the SN1 neurones. In the cockroach, 5-HT was assayed in the SN2 neurones only. In contrast to the locust, however, the 5-HT content of these cells was not significantly above that of control cells taken from other ganglia. These observations demonstrate that only the SN1 neurones are the source of the catecholaminergic fibres investing the locust and cockroach salivary glands. The difference in neurotransmitter content between the SN1 and SN2 neurones suggests that these neurones have separate functions in the control of salivary secretion.

Absorption, degradation and excretion of benzo(a)pyrene in the cricket (Acheta domesticus)

1. The absorption, degradation and excretion of 3H-benzo(a)pyrene (3H-BP) was examined in the cricket (Acheta domesticus). 2. After 3H-BP injection, extractable 3H-BP declined in the internal compartment over a 48 period. 3. When 3H-BP was deposited on the surface of the insect it penetrated through the cuticle, as evidenced by decrease in 3H-BP recovered in surface rinses and accumulation of 3H-BP internally. 4. Administration of 3H-BP by topical application or injection resulted in a progressive association of radioactivity with tissue debris and low-level metabolism to highly polar compounds. Both parent compound and highly polar metabolites were detected in excreta. 5. Treatment of insects with piperonyl butoxide decreased accumulation of polar products in excreta after injection of 3H-BP.

Characteristics and outcomes of insanity acquittees in Oklahoma

The insanity defense is perhaps the most vigorously debated topic at the interface of the legal and mental health systems. This article addresses the need for empirical evidence by providing data on insanity acquittees and their later outcomes in Oklahoma, a jurisdiction not previously studied. Information was obtained on the demographic, legal, psychiatric, hospitalization, and post-hospitalization characteristics of all 61 defendants acquitted not guilty by reason of insanity (NGRI) and treated on the state forensic unit during a 5-year period. Insanity acquittees had few resources, significant psychopathology, and extensive involvement with the legal and mental health systems prior to the NGRI offense. Follow-up of three groups of discharged patients--those released at an initial court review, those who completed the NGRI treatment program, and those who absconded from the forensic unit--revealed that those who escaped from the unit had significantly more arrests and subsequent legal charges than regularly discharged patients.

Effects of colchicine on central and peripheral nerve terminals of the locust Schistocerca gregaria

The treatment of locusts (Schistocerca gregaria) with colchicine leads to various changes in the ultrastructure of both central and peripheral nerve terminals. These changes include a marked reduction in synaptic vesicle density, which is further enhanced following stimulation. There are also increased numbers of coated pits and membraneous cisternae together with enlarged terminal areas and disruption of mitochondrial ultrastructure. The capacity of isolated central nerve terminals (synaptosomes) to take up the radiolabelled transmitter precursor [3H]-choline is enhanced following in vivo treatment of locusts with colchicine, whilst in vitro treatment leads to a reduction in choline uptake. The results are discussed with regard to the postulated effects of colchicine on axoplasmic transport.

The effect of in vivo stimulation on the cytology of neuromuscular junctions of locust flight muscles

The ultrastructure of neuromuscular junctions in dorsoventral (tergosternal) flight muscle no. 113 and dorsolongitudinal flight muscle no. 112 of the locust Schistocerca gregaria is described. Following in vivo stimulation by enforced flight, morphological and statistical analyses reveal cytological changes at these junctions suggestive of vesicular release of neurotransmitter and membrane recycling. Flight periods from 30 min to 3 h produced a progressive decrease in the density of terminal synaptic vesicles, an increase in terminal surface area and circumference, increases in the occurrence of membranous cisternae, increases in mitochondrial numbers, and increases in the frequency of coated pits.

Effect of taurine on neurotransmitter release from insect synaptosomes

The effect of taurine on the release of [3H]acetylcholine ([3H]ACH) and [3H]gamma-aminobutyric acid ([3H]GABA) from preloaded locust synaptosomes has been studied. Veratridine (100 microM) and K+ (100 mM) both evoked [3H]ACh release and this was reduced in a concentration-dependent manner by taurine (5, 10, and 20 mM). In contrast to this, veratridine induced no observable release of [3H]GABA, and the response to K+ was slight. In the presence of taurine, however, a concentration-dependent enhancement of [3H]GABA release was observed. Since nipecotic acid (1 mM), an inhibitor of neuronal GABA uptake, also revealed [3H]GABA release induced by veratridine, it is suggested that both this effect and that of taurine are due to prevention of GABA reuptake. These results suggest that taurine may act as a neuromodulator in insects.

Effect of taurine on calcium accumulation in resting and depolarised insect synaptosomes

The effect of taurine (2-aminoethanesulphonic acid) on 45Ca2+ accumulation in resting and depolarised synaptosomes obtained from the locust Schistocerca americana gregaria was studied. Taurine reduced 45Ca2+ accumulation in resting synaptosomes, and this effect was more pronounced when synaptosomes were depolarised with either high [K+] or veratridine. Veratridine-induced 45Ca2+ accumulation was not affected by either gamma-aminobutyric acid or leucine, but was reduced by both verapamil and tetrodotoxin.

Characteristics associated with change in the legal status of involuntary psychiatric patients

Patients initially admitted to a state hospital under an emergency commitment procedure were studied to identify the variables associated with their later change to voluntary status, release, or judicial commitment, and to compare the hospitalization and outcome patterns of voluntary and committed patients. Compared with committed or voluntary patients, released patients were younger and better educated; were more likely to be employed at admission, to contribute to family income, and to have had previous outpatient treatment; and were less likely to have serious organic or psychotic disorders or to receive government assistance. Voluntary patients were hospitalized twice as long as committed patients and were less frequently considered to have received maximum benefits from hospitalization. In view of the association between voluntary status and longer hospitalization, periodic review may be needed to safeguard these patients from unnecessary confinement.