A review of the assessment and treatment of anger and aggression in offenders with intellectual disability

Rates of aggression amongst people with intellectual disability (ID) have been found to be high in studies conducted on several continents across a number of service settings. Aggression is the primary reason for people with ID to be admitted or re-admitted to institutional settings, and it is also the main reason for individuals in this client group to be prescribed behaviour-control drugs. Anger is a significant activator of aggression, but little is known about the emotional aspects of the lives of people with ID. There are many reasons for this, but a lack of reliable and validated assessment measures is chief among them. The present review found that very little work has been conducted to date concerning the development of robust tools for assessing anger and aggression in this population. A narrative review of interventions for reducing aggression and anger in people with ID showed that there is virtually no evidence to support the use of psychotropic medications. Research has shown that behavioural interventions can be effective; however, they are intrusive and have not been tested in naturalistic settings with higher-functioning clients and low-frequency aggression. More recently, cognitive-behavioural interventions have shown promise, but the mechanisms for effective change have yet to be delineated. Priority research questions relating to assessment, treatment and therapeutic skills in working with anger and aggression problems are offered by the present review.

Cortically evoked neural volleys to the human hand are increased during ischaemic block of the forearm

Reorganisation of the motor cortex may occur after limb amputation or spinal cord injury. In humans, transcranial magnetic stimulation (TMS) shows expansion of motor cortical representations of muscles proximal to the injury. Similarly, ischaemic block of the hand can increase acutely the representation of the biceps muscle, measured by increased biceps motor potentials evoked by TMS. It is thought that this increase occurs at the expense of the cortical representation of the paralysed and deafferented hand muscles but this has never been investigated. To study what changes occur in the cortical representation of the hand muscles during ischaemic block, a tungsten microelectrode was inserted into the ulnar or median nerve above the elbow and the size of the neural potential elicited by TMS in fascicles supplying the hand was measured in seven subjects. Prior to ischaemia, TMS evoked EMG responses in the intrinsic hand muscles. In the nerve, a brief motor potential preceded the response in the muscle and was followed by a contraction-induced sensory potential. During 40 min of ischaemia produced by a blood pressure cuff inflated around the forearm to 210 mmHg, the EMG response to TMS and the sensory potential from the hand were progressively blocked. However, the motor neural evoked potential showed a significant increase in amplitude during the ischaemic period (30.5 %, P = 0.005). The increase in the neural potential suggests that output to the hand evoked from the cortex by TMS was not decreased by ischaemic block. Thus, we conclude that the increased response of biceps to TMS during distal ischaemia is not accompanied by a corresponding decrease in the motor cortical representation of the hand.

Balancing acts: respiratory sensations, motor control and human posture

1. The present brief review covers some novel aspects of integration between respiration and movement of the body. 2. There are potent viscerosomatic reflexes in animals involving small-diameter pulmonary afferents that, when excited, would limit exercise. However, recent studies using lobeline injections to excite pulmonary afferents in awake humans suggest that there is no evoked reflex motoneuronal inhibition. Instead, the noxious respiratory sensations generated by the vagal afferents may be crucial in the decision to stop exercise. 3. While respiratory movements may affect limb movements, the control of the trunk and limbs can involve interaction (and even interference) with key respiratory muscles, such as the diaphragm. Recent studies have revealed that not only does the diaphragm receive feed-forward drive prior to some limb movements, but that it also contracts both phasically and tonically during repetitive limb movements. 4. Thus, challenges to posture can indirectly challenge ventilation, while coordinated diaphragm contraction may contribute to control of the trunk.

Evaluation of a group intervention for convicted arsonists with mild and borderline intellectual disabilities

BACKGROUND

The extent to which people with intellectual disabilities (ID) set fires is difficult to ascertain. However, services working with people with ID and offending or quasi-offending histories are increasing the amount of attention that they give to this difficult and perplexing issue. This is due to the real and perceived threat that it presents to society and the seriousness with which it viewed by the criminal justice system.

AIM

Against this background there is very little available in the research literature concerning treatment interventions for fire-setting behaviour in this client group, and even less regarding their effectiveness.

METHOD

In the current study 14 men and women with mild and borderline ID, convictions for arson and detained in a hospital low secure service were offered and completed a broadly cognitive behavioural, approximately 40-session group-based intervention. The treatment was aimed primarily at reducing fire interest and attitudes associated with fire-setting behaviour. Participants were assessed pre- and post-treatment on a number of fire-specific, anger, self-esteem and depression measures.

RESULTS

Following treatment, significant improvements were found in all areas assessed, excepting depression. Despite the limitations of the study design, the results provide encouragement and some guidance to practitioners who are required to develop interventions for this challenging, yet much neglected client group.

Mechanisms of motor-evoked potential facilitation following prolonged dual peripheral and central stimulation in humans

1. Repetitive electrical peripheral nerve or muscle stimulation can induce a lasting increase in the excitability of the corticomotor projection. By pairing peripheral stimulation with transcranial magnetic brain stimulation it is possible to shorten the duration of stimulation needed to induce this effect. This ability to induce excitability changes in the motor cortex may be of significance for the rehabilitation of brain-injured patients. The mechanisms responsible for the increases in excitability have not been investigated thoroughly. 2. Using two paired transcranial magnetic stimuli protocols we investigated the excitability of intracortical inhibitory and excitatory systems before and following a period of repetitive dual muscle and brain stimulation. The dual stimulation consisted of motor point stimulation of first dorsal interosseous (FDI; 10 Hz trains of 1 ms square waves for 500 ms) delivered at one train every 10 s, paired with single transcranial magnetic stimulation given 25 ms after the onset of the train. 3. Following 30 min of dual stimulation, motor-evoked potentials (MEPs) were significantly increased in amplitude. During this period of MEP facilitation there was no significant difference in the level of intracortical inhibition. There was, however, a significant increase in the intracortical facilitation demonstrated with paired magnetic stimuli. The increase in facilitation was seen only at short interstimulus intervals (0.8-2.0 ms). These intervals comprised a peak in the time course of facilitation, which is thought to reflect I wave interaction within the motor cortex. 4. The relevance of this finding to the MEP facilitation seen following dual peripheral and central stimulation is discussed.

Unexpected reflex response to transmastoid stimulation in human subjects during near-maximal effort

1. In human subjects, a high-voltage electrical pulse between electrodes fixed over the mastoid processes activates descending tract axons at the level of the cervico-medullary junction to produce motor responses (cevicomedullary evoked responses; CMEPs) in the biceps brachii and brachioradialis muscles. 2. During isometric maximal voluntary contractions (MVCs) of the elbow flexors, CMEPs in the biceps brachii and brachioradialis muscles are sometimes followed by a second compound muscle action potential. This response can be observed in single trials (amplitude of up to 60 % of the maximal M wave) and follows the CMEP by about 16 ms in both muscles. The response only occurs during very strong voluntary contractions. 3. The second response following transmastoid stimulation appears with stimulation intensities that are at the threshold for evoking a CMEP in the contracting muscles. The response grows with increasing stimulus intensity, but then decreases in amplitude and finally disappears at high stimulation intensities. 4. A single stimulus to the brachial plexus during MVCs can also elicit a second response (following the M wave) in the biceps brachii and brachioradialis muscles. The latency of this response is 3-4 ms longer than that of the second response observed following transmastoid stimulation. This difference in latency is consistent with a reflex response to stimulation of large-diameter afferents. 5. The amplitude of the second response to transmastoid stimulation can be reduced by appropriately timed subthreshold transcranial magnetic stimuli. This result is consistent with intracortical inhibition of the response. 6. We suggest that transmastoid stimulation can elicit a large transcortical reflex response in the biceps brachii and brachioradialis muscles. The response travels via the motor cortex but is only apparent during near-maximal voluntary efforts.

Development of a method for mRNA differential display in filamentous fungi: comparison of mRNA differential display reverse transcription polymerase chain reaction and cDNA amplified fragment length polymorphism in Leptosphaeria maculans

We modified a technique, cDNA-AFLP, for identifying differentially expressed genes in plants to work in the filamentous fungus Leptosphaeria maculans (Desmaz.) Ces. & De Not. The cDNA fragments generated by our method ranged in size from approximately 100 to 400 bps. On average, twice as many cDNA fragments were amplified per primer set with cDNA amplified fragment length polymorphism in comparison with mRNA differential display reverse transcription polymerase chain reaction. The DNA fragments of interest were excised from gels and analyzed by single-stranded conformation polymorphism to eliminate nondifferentially expressed cDNA contamination. The method was used to examine gene expression differences between cultures grown in the presence or absence of an analog of the Brassica phytoalexin brassinin. Eleven of the fourteen fragments examined were determined by reverse Northern blot to be differentially expressed. In examining gene expression differences between young cultures not producing sirodesmins and older cultures that were producing these phytotoxins, we found 17 of 25 fragments were differentially expressed. Northern blots with these fragments confirmed the results.

Nucleus accumbens muscarinic receptors in the control of behavioral depression: antidepressant-like effects of local M1 antagonist in the Porsolt swim test

Systemically administered cholinomimetics or cholinesterase inhibitors can depress behavior in humans and animals, whereas antimuscarinic agents reverse this effect or even produce euphoria. Although these effects have been well documented, the specific brain regions that mediate them remain largely unknown. In the present experiments, muscarinic agonists and antagonists were locally injected into the nucleus accumbens of female Sprague-Dawley rats to test for their effects on behavioral depression in the Porsolt swim test and locomotor activity. Local, microinjections of the drugs in the accumbens elicited behaviors that were similar to the systemic effects reported in other studies. Injection of the non-specific agonist arecoline (40 and 80 microg) dose-dependently inhibited swimming and escape behavior. This may be mediated in part by accumbens M1 receptors because blocking these receptors with the specific antagonist pirenzepine (17.5 and 35.0 microg) did the opposite by increasing swimming. Gallamine (0.13, 0.44, and 0.88 microg), an antagonist at M2 receptors, dose-dependently decreased swimming. Two-way microdialysis suggested that this was in part due to the release of ACh by blocking M2 autoreceptors. Scopolamine, a mixed M1/M2 receptor antagonist, also released ACh but did not decrease swimming, probably because the M1 receptors were blocked; the drug (1.0 microg) increased swimming time, much like pirenzepine. With the exception of arecoline, none of the drugs significantly affected locomotor activity in a photocell cage. Arecoline (40 microg), which had decreased swimming, reduced activity. The present study suggests that muscarinic receptors in the nucleus accumbens can control immobility in the Porsolt swim test. The onset of immobility may depend on the activation of post-synaptic M1 receptors.

Changes in respiratory sensations induced by lobeline after human bilateral lung transplantation

1. The sensations evoked by the injection of lobeline into the right antecubital vein were studied in 8 subjects after bilateral lung transplantation and 10 control subjects. In control subjects, two distinct sensations were experienced. There was an early noxious sensation (onset approximately 10 s) followed by a late sensation of breathlessness (onset approximately 26 s) associated with involuntary hyperventilation. The early sensation was accompanied by respiratory and cardiovascular changes. 2. In contrast to control subjects, the early respiratory events and the noxious sensations evoked by injections of lobeline (18-60 microg kg(-1)) did not occur in subjects with recent bilateral lung transplantation. This suggests that the early respiratory sensations are mediated by the discharge of receptors in the lungs. 3. The late hyperventilation and the accompanying sensation of breathlessness occurred in both transplant and control subjects and are therefore likely to be mediated by receptors elsewhere in the body, presumably systemic arterial chemoreceptors stimulated by lobeline. 4. In control subjects, but not transplant subjects, there was a consistent decrease in mean arterial pressure associated with the lobeline injection. This suggests that pulmonary afferents mediate the hypotension. 5. For transplant subjects studied more than a year after transplantation, there was some evidence that the noxious respiratory sensations evoked by lobeline had returned. This suggests that some functional reinnervation of pulmonary afferents may occur.

Influence of the menstrual cycle on flight simulator performance after alcohol ingestion

OBJECTIVE

Previous studies investigating the influence of the menstrual cycle on cognitive functioning of women after alcohol ingestion have obtained inconsistent results. The present study tested the hypothesis that flight simulator performance during acute alcohol intoxication and 8 hours after drinking differs between the menstrual and the luteal phase of the menstrual cycle.

METHOD

White female pilots (N = 24) were tested during the menstrual and the luteal phases of their menstrual cycles. On each test day they performed a baseline simulator flight, consumed 0.67 g/kg ethanol, and performed an acute-intoxication and an 8-hour-carryover simulator flight.

RESULTS

Subjects reached highly significant increases in estradiol (E2) as well as progesterone (P) levels during the luteal test day. Yet, there were no significant differences in overall flight performance after alcohol ingestion between the menstrual and luteal phases during acute intoxication or at 8-hour carryover. We found no correlations between E, or P levels and overall flight performance. However, there was a statistically significant Phase x Order interaction: Pilots who started the experiment with their menstrual day were less susceptible to the effects of alcohol during the second test day than were pilots who started with their luteal day.

CONCLUSIONS

The tested menstrual cycle phases and varying E2 and P levels did not significantly influence postdrink flight performance. Because the present study included a comparatively large sample size and because it involved complex "real world" tasks (piloting an aircraft), we believe that the present findings are important. We hope that our failure to detect menstrual cycle effects will encourage researchers to include women in their investigations of alcohol effects and human performance.

Relationship between variations in estradiol and progesterone levels across the menstrual cycle and human performance

RATIONALE

Studies about whether or not the cognitive performance of women is influenced by changes in levels of sex steroid hormones across the menstrual cycle have produced ambiguous results.

OBJECTIVES

This study tested whether flight simulator performance differs significantly between the menstrual and the luteal phase of the menstrual cycle.

METHODS

In a within-subjects design, 24 female pilots were tested twice during their menstrual cycle: once during the menstrual and once during the luteal phase. On both test days they performed a 75-min simulator flight in a Frasca 141, a popular pilot training device.

RESULTS

Despite highly significant differences in estradiol (E2) as well as progesterone (P) levels on the 2 test days, and despite excluding subjects with anovulatory cycles from the analyses, there were no significant differences in overall flight performance between the menstrual and luteal phases. We found no significant correlations between E2 or P levels and flight performance.

CONCLUSIONS

We found no evidence that the tested menstrual cycle phases and their associated E2 and P levels significantly influence flight simulator performance. We consider these negative findings based on 24 subjects meaningful because previous studies on the influence of menstrual cycle on cognitive performance have not involved complex "real world" tasks such as piloting an aircraft and they obtained inconsistent results.

Isolation and characterization of novel defence-related genes induced by copper, salicylic acid, methyl jasmonate, abscisic acid and pathogen infection in Brassica carinata

Summary To examine the defence response in Brassica carinata we differentially screened a cDNA library made from CuCl(2)-treated (Cu) leaves. The sequence of 17 of the 27 cDNA clones examined that showed Cu-induction had a high similarity to defence genes from other plant species. Among other clones that showed higher expression in the Cu leaves were two cDNAs encoding polypeptides of 351 and 250 amino acids, designated BcCJS1 and BcCJAS1. BcCJS1 had similarity to S-adenosyl-l-methionine: salicylic acid carboxyl methyltransferase from Clarkia breweri. However, the enzyme activity was not found in extracts from E. coli expressing BcCJS1. BcCJAS1 did not show extensive similarity to any genes with known function in the databases but it did contain three regions of amino acid sequence that are frequently found in amidotransferases. A third Cu-induced mRNA, Bcp6PGL, showed very high (86%) similarity to a putative 6-phosphogluconolactonase (6PGL) from Arabidopsis thaliana. In addition to Cu induction, BcCJS1 expression was induced by methyl jasmonate (MeJA) and salicylic acid (SA), BcCJAS1 expression by MeJA, SA and abscisic acid and Bcp6PGL expression by MeJA. The expression of all three genes increased after Alternaria brassicae infection. BcCJS1 and BcCJAS1 were induced within 1 h after MeJA- but not until 3 h after SA-treatment. The expression of both genes was systemically induced after infection with a compatible or incompatible fungal pathogen. SA systemically induced only BcCJAS1. The effects of various inhibitors of signalling pathways on expression of the three genes were studied.

COX-1 inhibitory activity in extracts from Eucomis L'Herit. species

Non-steroidal anti-inflammatory compounds can relieve pain and inflammation associated with elevated levels of prostaglandins in the body and are proposed to be the agents responsible for the action of traditional herbal remedies associated with the reduction of pain, fever and inflammation. Primarily the bulbs and in some instances the leaves and roots, of Eucomis L 'Herit. species are widely utilized in South African traditional medicine for this purpose. A measure of the anti-inflammatory activity of plant extracts can be generated using the cyclooxygenase (COX-1) assay. High levels of COX-1 inhibitory activity were detected in crude extracts prepared from the leaves, bulbs and roots of Eucomis species. Of the 11 species tested, 9 species exhibited moderate COX-1 inhibitory activity (40-70%) for the aqueous bulb extracts. All 11 species showed COX-1 inhibitory activity of +/-70% or higher, for the ethanol bulb extracts. The bulb and root extracts (ethanol) showed, in general, the highest levels of COX-1 inhibitory activity, but most species exhibited no significant difference in activity between plant parts. Generally (for 7 of the 11 species), these levels did not differ significantly in specimens harvested in summer and in winter. IC50 values were calculated to be 72 microg ml(-1) for the bulb extract of E. autumnalis autumnalis, and 27 microg ml(-1) for the root extracts. The corresponding IC50 value for the leaf extract was estimated to be 15 microg ml(-1). The COX-1 inhibitors were relatively stable over time, both in solution (ethanol) and in the dried plant material. Extracts tested over a period of three years did not differ significantly in COX-1 inhibitory activity. These experimental results validate the extensive use of this plant in southern African traditional medicine.

Measuring outcomes of care for adolescents with emotional and behavioral problems

OBJECTIVES

To validate the prototype Adolescent Treatment Outcomes Module (ATOM), examine its sensitivity to clinical change, and determine its feasibility for administration in routine clinical settings.

METHOD

A sample of 67 adolescents, aged 11 through 18, was selected from new patients at two inpatient and two outpatient mental health programs. Adolescents and parents completed the ATOM and validating instruments at intake, 1 week postintake, and again at 6 months.

RESULTS

Nine self-report symptoms predicted positive diagnoses of oppositional defiant, conduct, anxiety, and depressive disorders on the basis of structured diagnoses, with sensitivities of 0.7 to 0.8. Test-retest correlations for outcome scales were largely excellent (>0.70). Scales that measured functioning at home, in school, and in the community were moderately correlated in the expected direction with global functioning. Decreases in symptom severity and functional impairment were generally associated with decreases in validating instruments. Administration time averaged 25 minutes for adolescents and 28 minutes for parents.

CONCLUSIONS

Both parents and adolescents readily completed the ATOM. Module scales demonstrated excellent reliability and good to fair concurrent validity. The ATOM was able to detect change and its absence.

Regulation of nitric oxide synthase 2 in rabbit corneal cells

PURPOSE

The purpose of these studies was to investigate the role of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta), and transforming growth factor-beta (TGF-beta) in the regulation of inducible nitric oxide synthase (NOS2) activity in rabbit corneal cells.

METHODS

Rabbit corneal epithelial, stromal, and endothelial cells were grown in culture and treated with cytokines and growth factors, alone or in combination. NOS activity was measured at times up to 72 hours after treatment by assaying the culture medium for nitrite using the Griess reaction. Cell lysates were analyzed by Western blot analysis for NOS2 protein. RNA was isolated and amplified with NOS1-, NOS2-, and NOS3-specific primers by RT-PCR.

RESULTS

NOS2 expression was induced by combined cytokine treatment from nondetectable levels to abundant levels in low passage (<4) stromal cells and to low levels in corneal endothelial cells but not in corneal epithelial cells. In the absence of IFN-gamma, little or no nitrite accumulation was induced by TNF-alpha, IL-1beta, or lipopolysaccharide (LPS) treatment. The inductive effects of IFN-gamma were antagonized in a dose-dependent manner by the myxoma virus rabbit IFN-gamma receptor homolog, M-T7. rRaIFN-gamma, in combination with IL-1beta and TNF-alpha, induced the appearance of NOS2 mRNA within 24 hours but detectable nitrite did not accumulate in large amounts (>10 microM) until after 24 hours postinduction. NOS2 was identified as a 130 kDa protein on Western blot analysis using monoclonal antibody against murine NOS2. TGF-beta(1) and beta(2) inhibited the accumulation of cytokine-induced nitrite in a dose-dependent manner while not significantly reducing the steady state level of NOS2 mRNA. The activity of the induced NOS was inhibited by 1400W, a NOS2-selective inhibitor, but not 7-nitroindazole, a NOS1-selective inhibitor.

CONCLUSIONS

In cultured corneal stromal cells, NOS2 expression was upregulated by IFN-gamma in combination with IL-1beta and TNF-alpha but not by any of these cytokines alone, while TGF-beta downregulated the activity. Cultures of corneal epithelial cells could not be induced to express NOS2, yet cultures of endothelial cells produced low amounts of NO in response to cytokines. The NOS1 and NOS3 isoforms were not detected in any of these corneal cells.

Transcranial magnetic stimulation and human muscle fatigue

During exercise, changes occur at many sites in the motor pathway, including the muscle fiber, motoneuron, motor cortex, and "upstream" of the motor cortex. Some of the changes result in fatigue, which can be defined as a decrease in ability to produce maximal muscle force voluntarily. Transcranial magnetic stimulation (TMS) over the human motor cortex reveals changes in both motor evoked potentials (MEPs) and the silent period during and after fatiguing voluntary contractions in normal subjects. The relationship of these changes to loss of force or fatigue is unclear. However, during a sustained maximal contraction TMS evokes extra force from the muscle and thus demonstrates the development of suboptimal output from the motor cortex, that is, fatigue at a supraspinal level. In some patients with symptoms of fatigue, the response to TMS after exercise is altered, but the changed MEP behavior is not yet linked to particular symptoms or pathology.

Toward a level playing field: predictive factors for the outcomes of mental health treatment for adolescents

OBJECTIVE

To understand better the effectiveness of routine treatment for emotional and behavioral problems experienced by adolescents, methods are needed to control for between-provider differences in the distribution of factors that adversely affect treatment success. Such methods are necessary to fairly compare providers' outcomes and to aid clinicians in identifying adolescents for whom routine care may need to be altered. As a preliminary step toward developing a model to adjust treatment outcomes to account for predictive factors, findings from studies of treated samples of adolescents were reviewed to identify the factors that influence the likelihood of treatment success for this population.

METHOD

Medline and PSYCInfo databases were searched for studies of treated adolescents that reported the association between expert-nominated predictive factors and outcomes. Thirty-four studies met inclusion criteria.

RESULTS

Significant predictors identified in these studies include diagnosis, baseline severity of symptoms and functional impairment, family dysfunction, and previous treatment. Several expert-nominated factors have not been adequately studied in treated samples.

CONCLUSIONS

Much basic work is needed before a convincing body of empirical evidence can explain predictive factors for adolescent mental health treatment outcomes. Future efforts should determine a reduced set of predictive factors that can be measured with minimal burden to providers.

Changes in muscle afferents, motoneurons and motor drive during muscle fatigue

Fatigue is a reduction of maximal muscle force or power that occurs with exercise. It is accompanied by changes at multiple levels in the motor pathway and also by changes in the discharge patterns of muscle afferents. Changes in afferent firing can lead to altered perceptions and can also act on the efferent pathway. Changes in the motor pathway include slowing of motor unit firing rates during sustained maximal voluntary contractions (MVCs). Muscle responses to stimulation at different levels of the motor pathway also change. Transcranial magnetic stimulation of the motor cortex and stimulation of descending tracts in the spinal cord in human subjects show an increase in the response of the cortex and a decrease in response of the motoneuron pool during sustained MVCs. In addition, the silent period following magnetic stimulation is prolonged. During relaxation after fatiguing exercise, muscle responses to stimulation of the motor cortex are initially facilitated and are then depressed for many minutes, whereas responses to descending tract stimulation are initially depressed but recover over about 2 min. Although some of the loss of force of fatigue does occur through inadequate drive to the muscle, it is not clear which, if any, of the changes described in the cortex or the motoneurons are responsible for loss of maximal voluntary force and thus contribute to fatigue. Changes may be associated with muscle fatigue without causing it.

Ethanol pharmacokinetics in white women: nonlinear model fitting versus zero-order elimination analyses

BACKGROUND

Studies have shown repeatedly that ethanol pharmacokinetics are not linear, yet most researchers still determine ethanol elimination by linear, zero-order kinetics. The goals of the present work were to: (1) fit four nonlinear pharmacokinetic models to mean breath alcohol concentration (BrAC)-time data of 27 women and determine the best-fit model; (2) fit the determined best-fit model to individual BrAC data and estimate the pharmacokinetic parameters; and (3) compare the method of nonlinear model fitting with the classical zero-order elimination method and determine in which cases the classical approach is justified.

METHODS

Twenty-seven healthy white women ingested four drinks (total of 0.67 g x kg(-1)) of ethanol on two test days. Approximately 24 breath ethanol samples (for pharmacokinetic analyses) and one blood sample (for hormonal markers) were taken per day. Pharmacokinetic model evaluation was based on the coefficient of variation, the weighted residual sum of squares, and the sequence of the weighted residuals. Because hormonal changes across the menstrual cycle did not significantly influence ethanol pharmacokinetics, data from the two test days were pooled.

RESULTS

The best-fit model was a one-compartment open model with first-order absorption and sequential first-order elimination, followed by Michaelis-Menten elimination kinetics. Fitting this model to the individual BrAC data yielded mean ka = 0.062 hr(-1), Vd = 0.457 L x kg(-1), ke = 0.011 hr(-1), Vmax = 0.136 g x L(-1) x hr(-1), and Km = 0.096 g x L(-1). For the classical analyses, mean time to peak BrAC = 1.83 hr, disappearance rate = 0.179 g x L(-1) x hr(-1), and area under the blood ethanol-time curve (AUC) = 2.884 g x L(-1) x hr. Correlational analyses showed that more frequent drinkers eliminated ethanol significantly faster and reached significantly lower AUC than less frequent drinkers.

CONCLUSIONS

After multiple dose ingestion in white women, classical zero-order elimination analyses can be applied only to a limited portion of the descending BrAC-time curve. They seem justified and practical from 0.5 hr after peak BrAC until BrAC reaches 0.2 g x L(-1). To describe ethanol pharmacokinetics across the entire BrAC-time curve, however, sophisticated nonlinear model fitting is required.

Interferon coordinately inhibits the disruption of PML-positive ND10 and immediate-early gene expression by herpes simplex virus

Interferons (IFNs) are important components of the innate immune response, limiting herpes simplex virus (HSV) infection. In recombinant HSV-infected cells, IFN inhibited expression of beta-galactosidase from the immediate-early gene, ICP4, promoter. The extent of inhibition was dependent on IFN dose, IFN type, cell type, and multiplicity of infection (moi). IFN inhibited gene transcription, leading to a complete block in ICP4 promoter-driven gene expression in 90% of cells. The same IFN treatments resulted in an increase in the size and number of nuclear domain 10 (ND10) structures that stained positive by immunofluorescence for the promyelocytic leukemia (PML) protein. In cultures infected at low moi with a recombinant HSV producing ICP4 as a fusion protein with green fluorescence protein, the appearance of green fluorescence in the nucleus coincided with loss of PML-positive ND10 in the same nucleus, even in the rare ICP4-expressing IFN-treated cells. IFN-dependent inhibition was nearly complete when the immediate-early promoter was in the viral genome but was minimal when the promoter was stably integrated into the cellular genome. These data reveal that IFN can completely block viral gene expression in infected cells and that enhancement of the ND10 structure, which is the site of initiation of HSV replication, correlates with the block in viral gene expression.

Plant part substitution--a way to conserve endangered medicinal plants?

Population growth, urbanization and the unrestricted collection of medicinal plants from the wild is resulting in an over-exploitation of natural resources in southern Africa. Therefore, the management of traditional medicinal plant resources has become a matter of urgency. In southern Africa the most frequently used medicinal plants are slow-growing forest trees, bulbous and tuberous plants, with bark and underground parts being the parts mainly utilized. A strategy which would satisfy the requirements of sustainable harvesting, yet simultaneously provide for primary health care needs, would be the substitution of bark or underground parts with leaves of the same plant. This paper outlines the concept of plant substitution, using preliminary results of our recent investigations into four of the most important and most threatened South African medicinal plants - Eucomis autumnalis (bulb), Siphonochilus aethiopicus (rhizome), Ocotea bullata (bark), and Warburgia salutaris (bark) - as a demonstration of the kind of research necessary. Extracts of various plant parts were compared chemically using TLC-analysis, and pharmacologically in terms of antibacterial activity and cyclooxygenase-1 inhibition in vitro. The importance of the concept of plant part substitution as a strategy for the conservation of medicinal plants in southern Africa is discussed in terms of the results obtained.

Supraspinal fatigue during intermittent maximal voluntary contractions of the human elbow flexors

Responses to transcranial magnetic stimulation in human subjects (n = 9) were studied during series of intermittent isometric maximal voluntary contractions (MVCs) of the elbow. Stimuli were given during MVCs in four fatigue protocols with different duty cycles. As maximal voluntary torque fell during each protocol, the torque increment evoked by cortical stimulation increased from approximately 1.5 to 7% of ongoing torque. Thus "supraspinal" fatigue developed in each protocol. The motor evoked potential (MEP) and silent period in the elbow flexor muscles also changed. The silent period lengthened by 20-75 ms (lowest to highest duty cycle protocol) and recovered significantly with a 5-s rest. The MEP increased in area by >50% in all protocols and recovered significantly with 10 s, but not 5 s, of rest. These changes are similar to those during sustained MVC. The central fatigue demonstrated by the torque increments evoked by the stimuli did not parallel the changes in the electromyogram responses. This suggests that part of the fatigue developed during intermittent exercise is "upstream" of the motor cortex.

Ischaemia after exercise does not reduce responses of human motoneurones to cortical or corticospinal tract stimulation

Motor unit firing rates and voluntary activation of muscle decline during sustained isometric contractions. After exercise, the responses to motor cortical and corticospinal stimulation are reduced. These changes may reflect motoneuronal inhibition mediated by group III and IV muscle afferents. To determine whether the post-contraction depression of the responses to corticospinal or motor cortical stimulation could be maintained by continued firing of ischaemically sensitive group III and IV muscle afferents, we examined responses in muscles that were held ischaemic after exercise. Following a sustained maximal voluntary contraction (MVC) of the elbow flexors lasting 2 min, the response to stimulation of the corticospinal tract was reduced but the usual recovery (over approximately 2 min) was not delayed when the muscles were maintained ischaemic for 2 min after the contraction. Following a sustained MVC, the time course of the reduction in the response to motor cortical stimulation (a gradual decrease over approximately 2 min, maintained for > 10 min) was also not altered if the muscle was held ischaemic. Mean arterial blood pressure rose to 155 +/- 12 mmHg during the 2 min MVC, declined to 125 +/- 9 mmHg immediately after it, but remained at this level without returning to pre-exercise levels (102 +/- 10 mmHg) until circulation to the arm was restored. This confirms that the sustained MVC activated a reflex dependent on group III and IV muscle afferents. This study shows that ischaemically sensitive group III and IV muscle afferents do not mediate depression of responses to motor cortical or corticospinal stimulation after fatiguing exercise. It also suggests that firing of such afferents does not directly inhibit motoneurones or motor cortical output cells.