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Biomedical subjects

V Russell

Publications and source records attributed to V Russell.

At least 19 recordsLinked to original sources
PubMed2006

Epidemiological profile and clinical associations of human bocavirus and other human parvoviruses.

BACKGROUND: Human bocavirus (HBoV) and PARV4 are newly discovered human parvoviruses. HBoV, which was first detected in respiratory samples, has a potential role in the development of human respiratory disease. The present study compared the frequencies, epidemiological profiles, and clinical backgrounds of HBoV and PARV4 infections with those of other respiratory virus infections, by evaluating diagnostic samples referred to the Specialist Virology Laboratory (SVL) at the Royal Infirmary of Edinburgh (Edinburgh, United Kingdom). METHODS: Anonymized samples and study subject information were obtained from the respiratory sample archive of the SVL. Samples were screened for HBoV, PARV4, B19, respiratory syncytial virus (RSV), adenoviruses, influenza viruses, and parainfluenza viruses by use of nested polymerase chain reaction. RESULTS: HBoV infection was detected in 47 (8.2%) of 574 study subjects, ranking third in prevalence behind RSV infection (15.7%) and adenovirus infection (10.3%). Peak incidences of HBoV were noted among infants and young children (age, 6-24 months) during the midwinter months (December and January) and were specifically associated with lower respiratory tract infections. HBoV infections were frequently accompanied by other respiratory viruses (frequency, 43%), and they were more prevalent among individuals infected with other respiratory viruses (17%), frequently adenovirus or RSV. All respiratory samples were negative for PARV4. CONCLUSIONS: In the present study, HBoV was a frequently detected, potential respiratory pathogen, with a prevalence and an epidemiological profile comparable to those of RSV. Identification of HBoV infections may be clinically important in the future.

Female↗
PubMed2001

NMDA-stimulated Ca2+ uptake into barrel cortex slices of spontaneously hypertensive rats.

The spontaneously hypertensive rat (SHR) is used as a model for attention-deficit hyperactivity disorder (ADHD), since it has behavioural characteristics that resemble the behavioral disturbances of ADHD, namely hyperactivity, failure to sustain attention, and impulsiveness. The aim of this study was to establish whether N-methyl-D-aspartate (NMDA) receptor function was altered in barrel cortex slices of 4- to 6- week-old SHR compared to their normotensive Wistar-Kyoto (WKY) control rats. The barrel cortex was dissected from brain slices corresponding to antero-posterior coordinates 8.7-4.8 mm with reference to the Paxinos and Watson (1986) atlas and divided into rostral, middle, and caudal regions. 45Ca2+ uptake was stimulated by incubating test slices in buffer containing 100 microM NMDA for 2 min at 35 degrees C. Total 45Ca2+ uptake into the entire barrel cortex as well as uptake into all regions of SHR barrel cortex was lower compared to WKY. Basal uptake into the entire barrel cortex as well as uptake into rostral and caudal regions of SHR barrel cortex was lower than WKY but basal uptake into the middle region was the same for both strains. There was no difference between SHR and WKY in NMDA-stimulated 45Ca2+ uptake into barrel cortex slices except for significantly lower NMDA-stimulated uptake into the middle region of SHR barrel cortex compared to WKY. These findings suggest that calcium metabolism is disturbed in the somatosensory cortex of SHR but that NMDA receptor function is not altered.

Animals↗
PubMed2000

Increased noradrenergic activity in prefrontal cortex slices of an animal model for attention-deficit hyperactivity disorder--the spontaneously hypertensive rat.

Spontaneously hypertensive rats (SHR) are used as a model for attention-deficit/hyperactivity disorder (ADHD) since SHR are hyperactive and they show defective sustained attention in behavioral tasks. Using an in vitro superfusion technique we showed that norepinephrine (NE) release from prefrontal cortex slices of SHR was not different from that of their Wistar-Kyoto (WKY) control rats when stimulated either electrically or by exposure to buffer containing 25 mM K(+). The monoamine vesicle transporter is, therefore, unlikely to be responsible for the deficiency in DA observed in SHR, since, in contrast to DA, vesicle stores of NE do not appear to be depleted in SHR. In addition, alpha(2)-adrenoceptor mediated inhibition of NE release was reduced in SHR, suggesting that autoreceptor function was deficient in prefrontal cortex of SHR. So, while DA neurotransmission appears to be down-regulated in SHR, the NE system appears to be under less inhibitory control than in WKY suggesting hypodopaminergic and hypernoradrenergic activity in prefrontal cortex of SHR. These findings are consistent with the hypothesis that the behavioral disturbances of ADHD are the result of an imbalance between NE and DA systems in the prefrontal cortex, with inhibitory DA activity being decreased and NE activity increased relative to controls.

Adrenergic alpha-Agonists↗
PubMed2000

Development of a method to evaluate glutamate receptor function in rat barrel cortex slices.

The rat is a nocturnal animal and uses its vibrissae extensively to navigate its environment. The vibrissae are linked to a highly organized part of the sensory cortex, called the barrel cortex which contains spiny neurons that receive whisker specific thalamic input and distribute their output mainly within the cortical column. The aim of the present study was to develop a method to evaluate glutamate receptor function in the rat barrel cortex. Long Evans rats (90-160 g) were killed by cervical dislocation and decapitated. The brain was rapidly removed, cooled in a continuously oxygenated, ice-cold Hepes buffer (pH 7.4) and sliced using a vibratome to produce 0.35 mm slices. The barrel cortex was dissected from slices corresponding to 8.6 to 4.8 mm anterior to the interaural line and divided into rostral, middle and caudal regions. Depolarization-induced uptake of 45Ca2+ was achieved by incubating test slices in a high K+ (62.5 mM) buffer for 2 minutes at 35 degrees C. Potassium-stimulated uptake of 45Ca2+ into the rostral region was significantly lower than into middle and caudal regions of the barrel cortex. Glutamate had no effect. NMDA significantly increased uptake of 45Ca2+ into all regions of the barrel cortex. The technique is useful in determining NMDA receptor function and will be applied to study differences between spontaneously hypertensive rats (SHR) that are used as a model for attention deficit disorder and their normotensive control rats.

Animals↗
PubMed1998

Differences between electrically-, ritalin- and D-amphetamine-stimulated release of [3H]dopamine from brain slices suggest impaired vesicular storage of dopamine in an animal model of Attention-Deficit Hyperactivity Disorder.

The spontaneously hypertensive rat (SHR) has behavioural characteristics which make it a suitable animal model for Attention-Deficit Hyperactivity Disorder (ADHD). The drugs of choice in the treatment of ADHD are methylphenidate and D-amphetamine. Using an in vitro superfusion system, we showed that both drugs released [3H]dopamine (DA) (and metabolites) from prefrontal cortex, nucleus accumbens and caudate-putamen slices, but methylphenidate was from 7- to 17-fold less potent than D-amphetamine. The similarity in the drug effects on SHR and WKY [3H]DA release is in accordance with the fact that there is no 'paradoxical effect' of psychomotor stimulants on ADHD behaviour. Methylphenidate released significantly less [3H]DA from nucleus accumbens slices obtained from SHR than from their normotensive Wistar-Kyoto (WKY) controls. Electrical stimulation released less [3H]DA from prefrontal cortex and caudate-putamen slices of SHR, while D-amphetamine, in contrast to methylphenidate, released more [3H]DA from prefrontal cortex, nucleus accumbens and caudate-putamen slices of SHR compared to WKY. Inhibition of the DA uptake carrier by low concentrations of methylphenidate increased the electrically-stimulated release of [3H]DA to the same extent in SHR and WKY tissue, suggesting that the DA transporter was not responsible for the differences between SHR and WKY. The present results suggest that SHR may have impaired vesicular storage of DA causing leakage of DA into the cytoplasm, since SHR released less [3H]DA from vesicular stores in response to methylphenidate or electrical stimulation and released more [3H]DA from cytoplasmic stores via the uptake carrier in response to D-amphetamine. Methylphenidate might be the drug of choice in the treatment of ADHD because it releases DA from vesicular stores only and is less potent than D-amphetamine, thus making it possible to adjust the dose and thereby 'normalise' reduced DA function more precisely than is possible with D-amphetamine. There was no difference between SHR and WKY with respect to D-amphetamine-stimulated release of [14C]acetylcholine (ACh) or methylphenidate-induced inhibition of the electrically-stimulated release of [14C]ACh from nucleus accumbens or caudate-putamen slices, suggesting that there is no major change in cholinergic transmission in SHR.

Animals↗
PubMed1996

Acute day hospitalization as an alternative to inpatient treatment.

OBJECTIVE: This paper describes the administrative process by which the Ottawa General Hospital (OGH) closed 6 beds and used the staff and space resources thus released to set up an acute day hospital (ADH) for the treatment of 8 acutely ill psychiatric patients. Outcome data are presented on the first 160 patients admitted to the ADH. METHODS: Demographic and clinical information including diagnostic (DSM-III-R; Global Assessment of Functioning [GAF]) and questionnaire data (Symptom Checklist-90 Revised [SCL-90R]; Beck Depression Inventory [BDI]; State-Trait Anxiety Inventory [STAI]; patient satisfaction) were obtained from 160 ADH patients at admission and discharge. Forty-two of these patients provided follow-up data 3 to 6 months postdischarge. The outcome of ADH patients was compared with that of a retrospectively obtained random sample (n = 100) of inpatients on selected diagnostic and demographic variables. RESULTS: On clinician-rated and self-report clinical scales, ADH patients showed significant clinical improvement reflected in higher GAF scores and less psychological distress, depression, and anxiety at discharge relative to admission. There were no significant group differences in outcome indices except for shorter length of stay in the ADH group compared with inpatients. The ADH group rated the program highly in help received and quality of service. Short-term follow-up showed that gains made during treatment were maintained 3 to 6 months later. CONCLUSIONS: These results show that a time-limited day hospital program is clinically effective for acutely ill psychiatric patients and leads to a more efficient use of inpatient resources. We believe that partial hospitalization for the treatment of acute psychiatric disorders may have wide application in psychiatric hospital practice.

Acute Disease↗
PubMed1995

Altered dopaminergic function in the prefrontal cortex, nucleus accumbens and caudate-putamen of an animal model of attention-deficit hyperactivity disorder--the spontaneously hypertensive rat.

The spontaneously hypertensive rat (SHR) has been proposed as an animal model for Attention-Deficit Hyperactivity Disorder (ADHD). The behavioural problems of ADHD have been suggested to be secondary to altered reinforcement mechanisms resulting from dysfunction of the mesolimbic and mesocortical dopaminergic systems. The present study therefore investigated whether there are regional differences in dopamine (DA) and acetylcholine (ACh) release and DA D2-receptor function in SHR compared to their normotensive Wistar-Kyoto (WKY) controls. The DA D2-receptor agonist, quinpirole, caused significantly greater inhibition of DA release from caudate-putamen but not from nucleus accumbens or prefrontal cortex slices of SHR relative to WKY. DA D2-receptor blockade by the antagonist, sulpiride, caused a significantly greater increase in DA release from nucleus accumbens slices of SHR compared to WKY suggesting increased efficacy of DA autoreceptors at low endogenous agonist concentrations in the nucleus accumbens of SHR. The electrically-stimulated release of DA was significantly lower in caudate-putamen and prefrontal cortex slices of SHR than in slices of WKY. This could be attributed to increased autoreceptor-mediated inhibition of DA release in caudate-putamen slices but not in the prefrontal cortex. No difference was observed between SHR and WKY with respect to DA D2-receptor-mediated inhibition of ACh release from caudate-putamen or nucleus accumbens slices, suggesting that postsynaptic DA D2-receptor function is not altered in SHR relative to WKY.

Acetylcholine↗
PubMed1994

Regulation of antibacterial protein synthesis following infection and during metamorphosis of Manduca sexta.

Larvae of the tobacco hornworm, Manduca sexta, respond to intrahemocoelic injection of bacteria or bacterial cell wall peptidoglycan with induced synthesis of a suite of antibacterial proteins. Previous studies have demonstrated peptidoglycan regulation of the synthesis of these antibacterial proteins. In addition to eliciting enhanced synthesis of antibacterial proteins, peptidoglycan fragments also elicit a "malaise syndrome" characterized by decreased feeding and growth, delayed metamorphosis, and altered excretion. We speculate that these symptoms may be components of a mechanism to flush out and sterilize the midgut lumen, one of the primary sources of bacterial infection in insects. Studies of naive larvae have demonstrated the accumulation of lysozyme in the differentiating pupal midgut epithelium and release of lysozyme into the pupal midgut lumen after the larval midgut epithelium has been sloughed off. These observations have been extended by the identification of potent bactericidal activity against E. coli and immunoreactive hemolin, together with lysozyme, in the lumen of the newly differentiated pupal midgut.

Animals↗
PubMed1994

Effect of amygdaloid kindling on rat striatal dopamine D1- and D2-receptors.

The effect of kindling on dopaminergic (DA) neurotransmission was assessed by measuring dopamine D1- and D2-receptor binding in the dorsal and ventral striatum of rats either 2 hours (short-term) or 3-4 weeks (long-term) after the last kindled seizure. Kindling did not have any significant long-term effect on DA D2-receptor Kd or Bmax values in the dorsal or ventral striatum or on DA D1-receptor parameters in the dorsal striatum. The short-term effect of kindled seizures was to abolish the asymmetry in DA D2-receptor density observed in the dorsal striatum of control rats. DA D1-receptor density was also increased in the dorsal striatum contralateral to the kindled amygdala of short-term rats. The short-term effects support the notion that limbic seizures can modify the lateral imbalance of DA activity in the striatum.

Amphetamine↗
PubMed1994

Evidence that noradrenergic neurons in the A1 and A2 nuclei are lesioned by low doses of 6-OHDA injected into the locus coeruleus.

In order to determine the specificity of a lesion aimed at the locus coeruleus (LC), various doses of 6-hydroxydopamine (6-OHDA), a neurotoxin which selectively lesions catecholaminergic neurons, were bilaterally infused into the LC. The noradrenaline (NA) concentration in the frontal cortex, hippocampus, hypothalamus, LC, A1 and A2 nuclei decreased with increasing doses of 6-OHDA. A 1 microgram dose of 6-OHDA injected bilaterally into the LC caused maximal depletion of the NA concentration in the frontal cortex, hippocampus and A1 and A2 nuclei. A dose of 2 micrograms 6-OHDA caused further depletion of the NA content of the hypothalamus and LC. These findings suggest that A1 and A2 neurons which project to the hypothalamus may have been lesioned or that the noradrenergic projection from the LC to the hypothalamus may be greater than was previously suspected. Alternatively, leakage of 6-OHDA into the cerebrospinal fluid may have occurred at the higher doses, thus directly exposing the hypothalamus to the toxic effects of 6-OHDA.

Animals↗
PubMed1994

Characteristics of patients who choose between two types of group psychotherapy.

Patient selection or matching to group psychotherapy is usually done by therapists. An alternative is to allow patients to "sample" and then select from different group therapies. In the current study characteristics of patients (N = 20) who selected from two types of group psychotherapy in a day-treatment program were examined. Patients were assessed on measures of current psychiatric symptomatology (Symptom Checklist 90-Revised [SCL-90R]; Derogatis, Rickles & Rock, 1976), psychological mindedness (McCallum & Piper, 1990) and psychological defenses Mechanisms Inventory (Ihilevich & Gleser, 1986). The two groups did not differ with regard to symptomatology or psychological mindedness. It was found that patients who chose a verbal and process-oriented psychotherapy tended to have externalizing defenses (turning anger against others and projection), however. These defenses appear to be congruent with this more emotionally expressive therapy. Patients who chose a structured and activity-oriented group psychotherapy tended to have internalizing defenses (repression/denial and intellectualization). These defenses seem consistent with this group therapy, which emphasized less emotional expressiveness. The implications of patient choice for group therapy and patient selection practices are discussed.

Adult↗
PubMed1992

Effect of amygdaloid kindling on [3H]dopamine and [14C]acetylcholine release from rat prefrontal cortex and striatal slices.

The involvement of the dopaminergic (DA) systems in the control of limbic kindled seizures is ill defined. The effects of kindling on DA activity may have been overlooked in the past, because of its subtle unilateral occurrence and/or the variance of the endogenous imbalance of DA activity in normal animals. In the present study rats were screened for their endogenous DA imbalance using amphetamine-induced rotational behaviour. Electrical or sham kindling was applied in the hemisphere with the higher endogenous DA activity. Sections of the bilateral prefrontal cortex and dorsal and ventral striatum were dissected either 2 hours or 21 days after the final seizure and the electrically stimulated release of [3H]DA and [14C]acetylcholine (ACh) determined. Release was also measured in the presence of quinpirole or sulpiride to assess the activity of pre- and postsynaptic DA D2-receptors. Long-term effects of kindling consisted of facilitation of ACh release in the ventral striatum contralateral to the kindled amygdala and bilateral depression of DA release in the prefrontal cortex. Kindling therefore produced area specific changes in neurotransmitter systems giving rise to increased pro-convulsive cholinergic activity in the ventral striatum and decreased anti-convulsive dopaminergic activity in the prefrontal cortex.

Acetylcholine↗
PubMed1992

Clinical assessment of fetal electrocardiogram monitoring in labour.

OBJECTIVE: To assess the potential clinical value of fetal electrocardiographic (ECG) monitoring in labour. DESIGN: Descriptive study of the use of ECG waveform analysis during labour and its correlation with other indices of fetal and neonatal well-being. SETTING: Teaching hospital in Oxford. SUBJECTS: 86 high risk pregnancies. MAIN OUTCOME MEASURES: Suitability of ST Segment Analyser (Cinventa, Sweden) for clinical use; relation between the T/QRS ratio during labour (an index of ST segment and T wave elevation) and intrapartum cardiotocography, umbilical artery pH at birth and Apgar scores; T/QRS ratio trends in labour. RESULTS: The system was robust and user-friendly. No statistically significant relation was found between T/QRS ratios in labour and FHR abnormalities in the cardiotocograph. There was a weak relation between T/QRS ratios and umbilical artery acidosis: at a cervical dilatation of 4 cm, the Spearman rank correlation of the mean T/QRS ratio with umbilical artery actual base deficit was r = -0.31, 0.05 greater than P greater than 0.01. The correlation of T/QRS with the umbilical artery pH was not statistically significant, although a trend was present (Spearman rank: r = -0.26, P greater than 0.05). Correlation of the T/QRS ratio with Apgar scores at 1 and at 5 min was not statistically significant. Only 3 of 16 infants with an Apgar score of less than 7 at 1 min had a mean T/QRS ratio above 0.25 at any time during labour. CONCLUSION: Further research is necessary before a decision can be made whether this new method of fetal monitoring should be introduced into clinical practice.

Acidosis↗
PubMed1991

The prevalence, aetiology and clinical significance of pseudo-sinusoidal fetal heart rate patterns in labour.

OBJECTIVE: To investigate the prevalence of sinusoidal and pseudo-sinusoidal fetal heart rate (FHR) patterns in labour and the relation between the characteristics of the FHR pattern and fetal outcome. DESIGN: A prospective observational study over a 6-month period in which all women who had continuous FHR monitoring in labour had their intrapartum cardiotocographs (CTGs) scrutinized for the presence of sinusoidal or pseudo-sinusoidal FHR patterns. SETTING: John Radcliffe Hospital, Oxford. SUBJECTS: 1520 women who had fetal monitoring during labour for various reasons. MAIN OUTCOME MEASURES: Both internal (electrocardiographic) and external (ultrasound) recordings of the FHR were analysed. Abnormal FHR patterns were related to obstetric characteristics and fetal outcome in terms of Apgar scores, umbilical artery pH and admission to the special care unit. RESULTS: No true sinusoidal FHR patterns were observed, but pseudo-sinusoidal FHR patterns were found in 230 of the 1520 CTGs examined (15%). Of these, 219 were classified as minor (amplitude 5-15 beats/min) and 11 as intermediate (amplitude 16-24 beats/min). Major pseudo-sinusoidal FHR patterns (amplitude greater than 24 beats/min) were not observed. Minor pseudo-sinusoidal FHR patterns had a mean duration of 21 (SD 13) min and typically occurred once or twice early in labour. Using logistic regression analysis a significant, independent relation was demonstrated between the presence of minor pseudo-sinusoidal FHR patterns and the use of pethidine (RR 1.84, 95% CI 1.3 to 2.59, P less than 0.0001) and epidural analgesia (RR 1.85, 95% CI 1.24 to 2.76, P less than 0.001). Intermediate pseudo-sinusoidal FHR patterns were found in association with both in utero fetal sucking and transient episodes of fetal hypoxia such as that caused by periodic umbilical cord compression. CONCLUSION: Pseudo-sinusoidal FHR patterns in labour will usually be associated with a normal fetal outcome but a careful fetal assessment is mandatory.

Blood Gas Monitoring, Transcutaneous↗
PubMed1991

Patient satisfaction with a psychiatric day treatment program.

Patient perceptions can contribute significantly to partial hospitalization program evaluation. A retrospective study of patients' satisfaction ratings and comments concerning a day treatment program using a discharge questionnaire yielded high degrees of satisfaction. This may reflect a priori selection biases toward patients who formed a working alliance within the program. Comparison with a group of patients admitted to the program who did not complete a discharge questionnaire failed to differentiate the two groups on the basis of demographic or clinical characteristics. Attendance by males admitted to the program who completed a questionnaire was significantly (p less than .01) more frequent than by males who did not complete the questionnaire. Consistency in individual component ratings with overall satisfaction with the program suggests nonspecific benefits, with group psychotherapy evoking polarized perceptions. The latter observation suggests the need for careful matching of patients with specific treatment modalities employed in a day treatment setting. Suggestions are made regarding the administration and construction of a patient satisfaction questionnaire as well as for the application of this measure in enhancing program efficacy.

Day Care, Medical↗
PubMed1990

Birth asphyxia and the intrapartum cardiotocograph.

The intrapartum cardiotocographs (CTGs) of 38 severely asphyxiated, term infants, born during a 17-month period, and those of 120 healthy term infants acting as controls were independently reviewed by three investigators who were unaware of the clinical outcome. Inter-observer agreement was good (Kappa statistic = 0.74, P less than 0.0001). The investigators found that cardiotocographic abnormalities were present in 33 of the asphyxiated infants (87%) and in 35 of the controls (29%) and predicted that the abnormalities were severe enough to lead to significant fetal metabolic acidosis at delivery in 23 asphyxiated infants (61%) and in 11 controls (9%). The differences between the two groups were highly significant (P less than 0.001). Using the traditional diagnostic criteria for fetal distress, the investigators found that fetal blood sampling was indicated in 58% of cases in the asphyxia group and in 20% of controls but was only performed in 16% of asphyxiated infants and in 8% of controls. Furthermore, the median response times of delivery suite staff for abnormal fetal heart rate patterns were similar whether the FHR changes, classified using Krebs' CTG scoring system, were moderate or severe: 80 min and 90 min, respectively. These findings suggest that interpretation of the intrapartum CTG continues to pose major problems for practising obstetricians.

Acidosis, Respiratory↗