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Biomedical subjects

P Morris

Publications and source records attributed to P Morris.

At least 19 recordsLinked to original sources
PubMed2000

Updating working memory for words: a PET activation study.

A PET study of 10 normal individuals was carried out to investigate the cerebral regions involved in the controlled updating of verbal working memory. Subjects viewed single concrete words on a computer monitor and detected occasional target words in an attended color. In the activating condition, a target was defined as a word that was identical to the previous word presented in the attended color. In the control condition, the target was a predesignated word. The same word lists, target probabilities, and target response demands were used for both conditions, with interword intervals constrained to ensure equivalence in the demand for target rehearsal. A comparison of the conditions found bilateral activation of dorsolateral prefrontal (middle frontal gyrus; MFG) and inferior parietal (supramarginal gyrus; SMG) cortical regions. Activation of the MFG is taken to reflect executive control by prefrontal regions over the working memory updating process linking posterior representations of the anticipated target stimulus to anterior representations of the planned response. It is proposed that the updating of the stimulus link is mediated via connections between the MFG and SMG. The role of the SMG as an amodal region binding the various modal representations in posterior association cortex of the word being retained in working memory is considered and reviewed. It is suggested that the combined activation of these regions is related to the executive control of goal-setting in planned behavior.

Blood Flow Velocity↗
PubMed2000

Antibiotics for persistent nasal discharge (rhinosinusitis) in children.

BACKGROUND: Nasal discharge (rhinosinusitis) is the result of inflammation of the mucosa of the upper respiratory tract, and is usually due to either infection or allergy. OBJECTIVES: To determine the effectiveness of antibiotics versus placebo or standard therapy in treating children with persistent nasal discharge (>10 days). SEARCH STRATEGY: The Cochrane Controlled Trials Register, MEDLINE, EMBASE, and bibliographies of relevant articles were searched. Authors and pharmaceutical companies were contacted. Date of most recent searches: March 2000. SELECTION CRITERIA: All randomized controlled trials that compared antibiotics versus placebo or standard therapy (decongestants or nasal saline drops). Trials which included the use of other medications were included if all participants were allowed equal access to such medications or if the additional or alternative therapies were regarded as ineffective. Trials that only combined or compared antibiotics with surgery, or sinus puncture and lavage, were not included in the review. DATA COLLECTION AND ANALYSIS: Data were extracted by a single reviewer for the following outcomes: clinical failure, failure to improve, clinical improvement, time to resolution, complications, side-effects and bacteriologic failure. For the dichotomous outcome variables of each individual study, proportional and absolute risk reductions were calculated using a modified intention-to-treat analysis. The summary weighted risk ratio and 95% confidence interval (fixed effects model) were calculated using the inverse of the variance of each study result for weighting (Cochrane statistical package, REVMAN version 4.3). MAIN RESULTS: A total of five studies involving 401 children compared antibiotics with placebo or standard therapy. Only one of the seven outcomes (clinical failure) was reported in all studies. Around 45% of children did not have a clinical success documented when reviewed 2-6 weeks after randomization. The control event rate varied from to 47-71% (mean 56%). The risk ratio estimated using a fixed effects model was 0.72 (95% CI 0.59, 0.89). The estimated effect size was consistent in four of the five studies. REVIEWER'S CONCLUSIONS: For children with persistent nasal discharge or older children with radiographically confirmed sinusitis, the available evidence suggests that antibiotics given for 10 days will reduce the probability of persistence in the short to medium-term. The benefits appear to be modest and around six children must be treated in order to achieve one additional cure. No long term benefits have been documented. These conclusions are based on a small number of small randomized controlled trials and additional larger well-designed studies are indicated.

Adolescent↗
PubMed2000

Chromosomal localization of cotransformed transgenes in the hexaploid cultivated oat Avena sativa L. using fluorescence in situ hybridization.

Fluorescence in situ hybridization (FISH) was used to localize two transgenes (gus and bar), carried on plasmids pACT-1F and pUBA, respectively, on mitotic metaphase squashes of T1 plants of the cultivated hexaploid oat Avena sativa L. cotransformed by microprojectile bombardment of embryogenic callus. Among the eight progeny analysed by FISH in each of two lines, we detected plants null, hetero- and homozygous for the two genes in one line, and plants null and heterozygous for the two genes in the other line. Our results demonstrated that in the two independent transformation events, the gus and bar genes had inserted in the same position relative to each other. In each transformation event, the insertions occurred on D satellite (SAT) chromosomes bearing a C genome translocation.

Avena↗
PubMed2000

Severe haemolysis after an ABO unmatched kidney transplant - a nonsecretor transplanted from a donor with high anti-A titre.

A case of severe haemolysis following an ABO unmatched renal transplant is reported in a group A nonsecretor who received a kidney from a group O living related donor. Following the haemolytic episode, group A donor units were incompatible and the patient was transfused with group O blood. Serological investigation of the recipient revealed anti-A present in the serum and on the red cells. Investigation of the donor revealed the presence of high-titre anti-A. The association of such high-titre donor antibody with haemolysis in ABO unmatched grafts has not been reported before. We discuss the risk factors for developing haemolysis in an ABO unmatched organ transplant and explore the possible relevance of such high donor antibody titre to recipients who are nonsecretors.

ABO Blood-Group System↗
PubMed1999

Detecting activations in event-related fMRI using analysis of variance.

The most common design of a functional MRI (fMRI) experiment is a block design. The use of rapid imaging, however, and carefully designed paradigms makes the separation of cognitive events possible. Such experiments make use of event-related paradigms, in which a task involving several cognitive processes is repeated. In analyzing data from such experiments, existing methods often prove inadequate, because the prediction of the exact shape or timing of the time course is difficult. Here we present an analysis of variance (ANOVA) method for analyzing fMRI data that does not require any assumptions about the shape of the activation time course. Consequently, this method can simultaneously detect brain areas showing a variety of stimulus-locked time courses in the same experiment. The utility of this technique is demonstrated by the analysis of data from two event-related paradigms in which regions of activation are detected that correspond to a variety of distinct neural processes, yielding significantly different temporal signal changes. Magn Reson Med 42:1117-1122, 1999.

Analysis of Variance↗
PubMed1999

A Canadian multicenter, double-blind study of paroxetine and fluoxetine in major depressive disorder.

BACKGROUND: Recent studies have suggested clinical differences among selective serotonin reuptake inhibitors. In a 12-week randomized, multicenter, double-blind trial, the antidepressant and anxiolytic efficacy of the selective serotonin reuptake inhibitors paroxetine and fluoxetine was compared in patients with moderate to severe depression. METHODS: A total of 203 patients were randomized to fixed doses (20 mg/day) of paroxetine or fluoxetine for the first six weeks of therapy. From week 7-12, dosing could be adjusted biweekly, as required (paroxetine 20-50 mg/day, and fluoxetine 20-80 mg/day). The mean prescribed doses were paroxetine 25.5 mg/day (range 20.0-40.2 mg/day), and fluoxetine 27.5 mg/day (range 20.0-59.5 mg/day). Emergence of motor nervousness or restlessness was assessed using the ESRS scale for akathisia. RESULTS: Both active treatments demonstrated comparable antidepressant efficacy (HAM-D, CGI). Anxiolytic activity of the two drugs (COVI, STAI, HAM-D) was also comparable. However, paroxetine was found to be superior to fluoxetine on two subscore measures at week 1 of therapy (HAM-D Agitation item, p < 0.05; Psychic Anxiety item, p < 0.05), with no differences detected after week 2. The overall incidence of adverse effects was comparable in the two treatment groups. Constipation, dyspepsia, tremor, sweating and abnormal ejaculation were more common in paroxetine-treated subjects, whereas nausea and nervousness were more frequent in fluoxetine-treated patients. Weight loss was more common in the fluoxetine versus paroxetine group (11.88% versus 2.94%, respectively). ESRS scores for akathisia were low throughout the study and showed little change. LIMITATIONS: Differences observed between the two drugs in antianxiety effects were limited to two measures of anxiety among several others. DISCUSSION: The data indicate that paroxetine and fluoxetine have comparable antidepressant and anxiolytic efficacy. Paroxetine appears to produce an earlier improvement in agitation and psychic anxiety symptoms compared with fluoxetine.

Adult↗
PubMed1999

Treatment outcome in Australian veterans with combat-related posttraumatic stress disorder: a cause for cautious optimism?

This study investigated treatment outcome in combat-related posttraumatic stress disorder (PTSD). Participants were 419 Australian Vietnam veterans who completed a 12-week hospital-based program. A comprehensive protocol assessed PTSD, comorbidity, and social functioning at admission and at 3 and 9 months posttreatment. Overall, the group showed significant improvements in core PTSD symptoms, anxiety, depression, alcohol abuse, social dysfunction, and anger. Changes occurred mostly between admission and 3 months posttreatment, with gains maintained at 9 months. Ratings by patients and their partners indicated perceived improvement and strong satisfaction with treatment. Nevertheless, treatment gains were variable and, for most veterans, considerable pathology remained following the programs. The current study provides grounds for cautious optimism in the treatment of combat-related PTSD.

Alcoholism↗
PubMed1999

Streptococcus pneumoniae antibiotic resistance in Northern Territory children in day care.

BACKGROUND: There is evidence that the rapid rise in Streptococcus pneumoniae (SP) antimicrobial resistance seen in other countries may have commenced in Australia. Streptococcus pneumoniae carriage and resistance levels are described for urban Northern Territory children in day care. METHODS: A prospective cohort study was conducted of 250 children in nine Darwin day care centres between 24 March and 15 September 1997. Each fortnight nasopharyngeal swabs were collected from children, and parents were interviewed about medications administered. RESULTS: Streptococcus pneumoniae was detected in 52% (1028/1974) of all nasopharyngeal swabs. Streptococcus pneumoniae was isolated from 92% (231/250) of children at some time. Penicillin resistance was found in 30% (312/1028) of isolates using a screening test. Of these, 256 (82%) had resistance confirmed by E-test. Two hundred and one (20% of all isolates) had intermediate penicillin resistance and 55 (5% of all isolates) had high level resistance. Ceftriaxone resistance was found in 19% of children's first isolates. Resistance to other antibiotics was also common: co-trimoxazole 45%, erythromycin 17%, tetracycline 17% and chloramphenicol 13%. A total of 17% (172/1028) of the isolates were multiresistant. The average fortnightly proportion of children given antibiotics was 16% (405/2476). CONCLUSION: Levels of intermediate and high level penicillin resistance in this day care population are consistent with previous data from the Northern Territory, and considerably higher than the rest of Australia. The national trend of increasing pencillin resistance is likely to continue.

Australia↗
PubMed1999

Surgery for suspected neurogenic thoracic outlet syndromes: a follow up study.

OBJECTIVES: To assess the outcome of surgical treatment for thoracic outlet syndrome (TOS), and to compare the outcome in patients with and without an underlying cervical rib. METHODS: a heterogeneous group of 40 patients (33 women, seven men; aged 22-62 years) were evaluated 3 months to 20 years after surgery for suspected neurogenic TOS. Forty nine operations had been performed: cervical ribs were removed in 23 patients, together with fibrous band excision in nine. In the 17 without a cervical rib the thoracic outlet was decompressed by resection of the first thoracic rib in nine, and by other operations in eight. RESULTS: After surgery patients reported improved pain (33/36), sensory disturbance (30/35), hand muscle strength (14/27), and hand function (23/34). Postoperatively TOS recurred in two, and symptoms continued to progress in three patients in whom other diagnoses eventually emerged. Surgical complications were recorded in 10 patients, but were transient and did not result in permanent symptomatic sequelae. CONCLUSIONS: Surgical treatment of suspected neurogenic TOS relieves pain and sensory disturbance (90%), but is less effective for muscle weakness (50%). Surprisingly, surgery relieved sensory and motor abnormalities to a similar degree in patients both with and without a cervical rib. Ideally, patients require early operation to forestall permanent hand muscle denervation, but, our retrospective analysis fails to identify any single preoperative diagnostic criterion for TOS, particularly in patients lacking a radiographic cervical rib.

Adolescent↗
PubMed1999

Interventional neuroradiology in the treatment of brain tumors.

The current role of the interventional neuroradiologist in the treatment of brain tumors is limited to preoperative devascularization of vascular tumors and, occasionally, palliative therapy of metastatic or inoperable disease. Research protocols are in progress examining the role of intraarterial chemotherapy with disruption of the blood-brain barrier and may harbinger an expanded role for endovascular therapy in this group of patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Isolation of ATMEKK1 (a MAP kinase kinase kinase)-interacting proteins and analysis of a MAP kinase cascade in Arabidopsis.

In plants, a number of MAP kinase (MAPK), MAPK kinase (MAPKK), and MAPKK kinase (MAPKKK) homologues have been reported. However, there have been no reports of protein-protein interactions between these kinases or molecular analysis of MAPK cascades in higher plants. To analyze a possible MAPK cascade in Arabidopsis thaliana, we took two molecular approaches. One is the two-hybrid screening of ATMEKK1 (a MAPKKK)-interacting proteins; the other is an analysis of physical and functional interactions among isolated MAPK, MAPKK, and MAPKKK homologues from Arabidopsis. In two-hybrid screening using ATMEKK1 as bait, we isolated a novel MAPKK homologue, ATMKK2, a MAPK homologue, ATMPK4, and an unknown protein. ATMKK2 has high sequence similarity with MEK1 (a MAPKK) in Arabidopsis. Based on yeast two-hybrid analysis, we detected protein-protein interactions between ATMEKK1 and ATMKK2/MEK1 (MAPKKs), between ATMKK2/MEK1 and ATMPK4 (a MAPK), and between ATMPK4 and ATMEKK1. ATMPK4 and ATMKK2/MEK1 interacted with two distinct regions of ATMEKK1, the N-terminal regulatory domain and the C-terminal kinase domain, respectively. Coexpression of ATMEKK1 increased the ability of two closely related MAPKKs, ATMKK2 and MEK1, to complement a growth defect of the yeast pbs2 mutant. Coexpression of ATMPK4 and MEK1 complemented a growth defect of the yeast mpk1 and bck1 mutants. By contrast, other combinations of MAPKs and MAPKKs did not suppress these yeast mutations. These results suggest that ATMEKK1, ATMKK2/MEK1, and ATMPK4 may constitute a MAP kinase cascade.

Alanine↗
PubMed1998

Identification of a possible MAP kinase cascade in Arabidopsis thaliana based on pairwise yeast two-hybrid analysis and functional complementation tests of yeast mutants.

A possible MAP kinase (MAPK) cascade of Arabidopsis thaliana was identified on the basis of both yeast 2-hybrid analysis and complementation analysis of yeast mutants. Specific protein-protein interactions between ATMPK4 (a MAPK) and MEK1 (a MAPKK) and interactions between MEK1 and ATMEKK1 (a MAPKKK) were detected by using the 2-hybrid system. A growth defect of the yeast mpk1delta mutant was reversed by coexpression of ATMPK4 and MEK1. Coexpression of the N-terminal deletion form of ATMEKK1 increased the ability of MEK1 to suppress a growth defect of the yeast pbs2delta mutant. These results suggest that ATMPK4, MEK1, and ATMEKK1 may interact with each other and constitute a specific MAPK cascade in Arabidopsis. This is the first demonstration of a possible MAPK cascade in plants.

Arabidopsis↗
PubMed1998

Long-term effects of nurse home visitation on children's criminal and antisocial behavior: 15-year follow-up of a randomized controlled trial.

CONTEXT: A program of home visitation by nurses has been shown to affect the rates of maternal welfare dependence, criminality, problems due to use of substances, and child abuse and neglect. However, the long-term effects of this program on children's antisocial behavior have not been examined. OBJECTIVE: To examine the long-term effects of a program of prenatal and early childhood home visitation by nurses on children's antisocial behavior. DESIGN: Fifteen-year follow-up of a randomized trial. Interviews were conducted with the adolescents and their biological mothers or custodial parents. SETTING: Semirural community in New York. PARTICIPANTS: Between April 1978 and September 1980, 500 consecutive pregnant women with no previous live births were recruited, and 400 were enrolled. A total of 315 adolescent offspring participated in a follow-up study when they were 15 years old; 280 (89%) were born to white mothers, 195 (62%) to unmarried mothers, 151 (48%) to mothers younger than 19 years, and 186 (59%) to mothers from households of low socioeconomic status at the time of registration during pregnancy. INTERVENTION: Families in the groups that received home visits had an average of 9 (range, 0-16) home visits during pregnancy and 23 (range, 0-59) home visits from birth through the child's second birthday. The control groups received standard prenatal and well-child care in a clinic. MAIN OUTCOME MEASURES: Children's self-reports of running away, arrests, convictions, being sentenced to youth corrections, initiation of sexual intercourse, number of sex partners, and use of illegal substances; school records of suspensions; teachers' reports of children's disruptive behavior in school; and parents' reports of the children's arrests and behavioral problems related to the children's use of alcohol and other drugs. RESULTS: Adolescents born to women who received nurse visits during pregnancy and postnatally and who were unmarried and from households of low socioeconomic status (risk factors for antisocial behavior), in contrast with those in the comparison groups, reported fewer instances (incidence) of running away (0.24 vs 0.60; P = .003), fewer arrests (0.20 vs 0.45; P = .03), fewer convictions and violations of probation (0.09 vs 0.47; P<.001), fewer lifetime sex partners (0.92 vs 2.48; P= .003), fewer cigarettes smoked per day (1.50 vs 2.50; P= .10), and fewer days having consumed alcohol in the last 6 months (1.09 vs 2.49; P = .03). Parents of nurse-visited children reported that their children had fewer behavioral problems related to use of alcohol and other drugs (0.15 vs 0.34; P = .08). There were no program effects on other behavioral problems. CONCLUSIONS: This program of prenatal and early childhood home visitation by nurses can reduce reported serious antisocial behavior and emergent use of substances on the part of adolescents born into high-risk families.

Adolescent↗
PubMed1998

The effects of cocaine on nonhuman primate brain function are age dependent.

The effects of acute intravenous (i.v.) cocaine (COC) on several complex brain functions were studied in rhesus monkeys at 1.5, 3 and 10-11 years of age. Subjects performed several operant tasks (for food) that were used to model learning, short-term memory, color and position discrimination, and motivation, and disruption of performance of these tasks was used to quantitate drug effect. Drug effects were age dependent: The youngest subjects were 3 to 10 times less sensitive than the oldest. Presuming the observed behavioral effects of cocaine were caused primarily via its interaction with dopamine (DA) systems, changes in sensitivity to its effects with age are likely a reflection of the functional status of the DA system. These data, along with preliminary data on levels of DA transporters, suggest that the age-related differences in sensitivity to cocaine lie in, 'downstream' from, the dopamine receptor.

Aging↗
PubMed1998

Platelet paroxetine binding in post-traumatic stress disorder.

Sixty-two subjects, 45 with post-traumatic stress disorder (PTSD) and 17 healthy control subjects, were examined in a study of serotonin function measured by [3H]paroxetine binding to platelet membranes. Subjects were selected from male combat exposed veterans. The mean (+/- S.D.) Kd was 0.078 +/- 0.045 nM for the PTSD patient group and 0.064 +/- 0.037 nM for the control group. The mean Bmax was 934 + 238 fmol/mg protein for the PTSD patient group and 1011 +/- 363 fmol/mg protein for the control group. There was no significant difference between the groups for either Kd or Bmax before or after controlling for season of sampling. There were no significant differences between subjects with current PTSD and those with PTSD in the past, or between PTSD subjects with or without concurrent major depressive disorder. This study finds no relationship between PTSD, major depressive disorder and peripheral serotonin function measured by [3H]paroxetine binding to blood platelets.

Adult↗