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Biomedical subjects

J Morton

Publications and source records attributed to J Morton.

At least 73 records · Page 4Linked to original sources
PubMed1999

Creatine supplementation increases muscle total creatine but not maximal intermittent exercise performance.

This study investigated creatine supplementation (CrS) effects on muscle total creatine (TCr), creatine phosphate (CrP), and intermittent sprinting performance by using a design incorporating the time course of the initial increase and subsequent washout period of muscle TCr. Two groups of seven volunteers ingested either creatine [Cr; 6 x (5 g Cr-H(2)O + 5 g dextrose)/day)] or a placebo (6 x 5 g dextrose/day) over 5 days. Five 10-s maximal cycle ergometer sprints with rest intervals of 180, 50, 20, and 20 s and a resting vastus lateralis biopsy were conducted before and 0, 2, and 4 wk after placebo or CrS. Resting muscle TCr, CrP, and Cr were unchanged after the placebo but were increased (P < 0.05) at 0 [by 22.9 +/- 4.2, 8.9 +/- 1.9, and 14.0 +/- 3.3 (SE) mmol/kg dry mass, respectively] and 2 but not 4 wk after CrS. An apparent placebo main effect of increased peak power and cumulative work was found after placebo and CrS, but no treatment (CrS) main effect was found on either variable. Thus, despite the rise and washout of muscle TCr and CrP, maximal intermittent sprinting performance was unchanged by CrS.

Adolescent↗
PubMed1999

Characteristics, context and consequences of memory recovery among adults in therapy.

BACKGROUND: There are concerns that memories recovered during therapy are likely to be the result of inappropriate therapeutic techniques. AIMS: To investigate systematically these concerns. METHOD: One-hundred and eight therapists provided information on all clients with recovered memories seen in the past three years, and were interviewed in detail on up to three such clients. RESULTS: Of a total of 690 clients, therapists reported that 65% recalled child sexual abuse and 35% recalled other traumas, 32% started recovering memories before entering therapy. According to therapists' accounts, among the 236 detailed client cases very few appeared improbable and corroboration was reported in 41%. Techniques to aid recall were used in 42%, but only in 22% were they used before memory recovery started. CONCLUSIONS: Some of the data are consistent with memories being of iatrogenic origin, but other data clearly point to the need for additional explanations.

Age Distribution↗
PubMed1999

A case of recurrent congenital fetal anomalies associated with a familial subtelomeric translocation.

The potential of a new fluorescent in situ hybridization technique is discussed, which uses a complete set of telomeric probes to reveal cryptic chromosome rearrangements that remain undetected by standard cytogenetic analysis. We report the obstetric history of a patient who had a termination of pregnancy at 20 weeks for a fetus with multiple congenital anomalies but a normal male karyotype using conventional G-banding analysis on a mid-trimester placental biopsy. In a subsequent pregnancy, a diaphragmatic hernia and intra-uterine growth restriction were detected at 34 weeks' gestation and a fetal blood sample showed a normal female karotype. However, her child was born with dysmorphic features and additional severe abnormalities including microcephaly, anophthalmos and left fixed talipes. The child has shown marked developmental delay. In view of a strong family history of congenital abnormalities and recurrent miscarriage suggestive of a familial translocation, a fluorescent in situ hybridization technique using specific telomeric probes was performed on blood from the affected child and her parents. An unbalanced subtelomeric translocation was detected involving the long arms of chromosomes 2 and 7 in the child and a balanced translocation was detected in her father. Accurate genetic counselling and the opportunity for early prenatal diagnosis can now be offered to this family.

Abnormalities, Multiple↗
PubMed1999

Heritable variation and mechanisms of inheritance of spore shape within a population of Scutellospora pellucida, an arbuscular mycorrhizal fungus.

Substantial variation was found among single-spore cultures established from a single population of the arbuscular mycorrhizal fungus Scutellospora pellucida. A common environment experiment demonstrated that five single-spore cultures differed in their average spore shape (as measured by length:width ratios) and size (volume) with interisolate heritabilities of offspring mean values of 0.96 and 0.87, respectively (0.66 and 0.43 for the shape and size of individual spores). The distribution of offspring spore shapes also differed in levels of variance, skewness, and kurtosis. In fact, these aspects of the distributions shifted with mean spore shape as predicted by the binomial distribution-the distribution expected due to the segregation of genetically diverse nuclei through dividing hyphae. Thus, the original parental spores generating these cultures appear to have contained genetically variable nuclei, which then segregate into the offspring spores to generate consistent differences in the mean, variance, skewness, and kurtosis of the distribution of offspring spore shapes. This nuclear segregation may be followed by the assemblage of novel combinations of nuclei through hyphal fusion. Together these processes are rarely considered mechanisms for the creation of novel genetic combinations and may contribute to the maintenance of the high level of heritable variation observed in this study.

Journal Article↗
PubMed1998

Modelling the training effects of kinaesthetic acuity measurement in children.

In previous papers (Sims, Henderson, Hulme, & Morton, 1996a; Sims, Henderson, Morton, & Hulme, 1996b) we have found that the motor skills of clumsy children are capable of significant improvement following relatively brief interventions. Most remarkably, this included a 10-minute intervention while testing the kinaesthetic acuity of the children using a staircase method (Pest). In this paper, we show that Pest testing improves the kinaesthetic acuity of normal children as well. We analyse the available data on the development and improvement of motor skills and kinaesthetic acuity and derive a causal model for the underlying skills. We show that at least three independent cognitive/biological components are required to account for the data. These three components are affected differently by the various interventions that have been tried. We deduce that improvement on a general test of motor impairment can be found as a result of training in kinaesthetic acuity or through other, independent factors.

Child↗
PubMed1997

Predictors for optimal mobilization and subsequent engraftment of peripheral blood progenitor cells following intermediate dose cyclophosphamide and G-CSF.

Fifty consecutive patients undergoing cyclophosphamide/G-CSF mobilization were studied for indicators predictive for adequate harvest (CD34+ cells > 2 x 10(6)/kg, CFU-GM > 1 x 10(5)/kg). Target yields following a single leukopheresis were achieved for 66% of patients (89% with no previous alkylation chemotherapy or radiotherapy). Previous alkylation therapy, radiotherapy and low collection day platelet count were predictive of poor collection yields. Following reinfusion, the median time to platelets > 20 x 10(9)/l (PLT > 20) was 10 days and to neutrophils > 500 x 10(6)/l (ANC > 500) was 13 days. Total CD34+ cells infused was predictive of early platelet engraftment. Previous radiotherapy was inversely predictive of neutrophil engraftment. For the majority of patients not exposed to alkylation therapy or radiotherapy, adequate progenitor cells can be collected following a single leukopheresis. In patients suitable for future autologous bone marrow transplantation it would seem appropriate to avoid or minimize radiotherapy and alkylation therapy exposure in the pre-collection period.

Adolescent↗
PubMed1997

Free associations with EPS and memory.

In celebrating 50 years of EPS involvement in memory, I have taken a personal line rather than trying to achieve even coverage. Accordingly, the paper is in three parts. In the first, some early papers that have resonance for today's debates are described. Their framework was Bartlettian, with versions of schema theory as the guiding principles, and they were formative in my undergraduate education. This phase ended in the 1950s. From then, there was an explosion of work in memory in the U.K., the most important parts of which saw light at the EPS. This requires a proper history, which requires a proper space. In the second part, then, rather than show favourites or sample at random, my own involvement in EPS and memory is fallibly revisited, to give some flavour of the excitement, as well as some of the ideas. In the final part, some current work is described, and the Current State Buffer is introduced, in the hope of anticipating a little of the next 50 years.

History, 20th Century↗
PubMed1997

Memories for the Marchioness.

We examined the accounts of 27 survivors of the Marchioness ferry sinking, using cross-validation of accounts to search for instances of motivated forgetting. In order to identify objective items that could be validated, we focused the analysis on subjects' statements of whom they were with at various stages of the disaster. We compared these findings with an informal recall of a non-traumatic event after an interval of a few days. The main finding was that recall was reasonably good for both traumatic and non-traumatic events. Specifically, in the Marchioness sample, among those 86 statements that could have been confirmed in the accounts of other informants, 74 were in fact confirmed. Of the remaining 12 unconfirmed statements, only one involved a contradiction. We conclude that for a disaster of this kind, and with this particular sample of individuals, motivated forgetting was extremely rare.

Amnesia↗
PubMed1997

Total hip arthroplasty for complications of proximal femoral fractures.

OBJECTIVES: To determine problems associated with and to present the results of secondary total hip replacement for complications of proximal femoral fractures. SETTING: An acute care hospital with a prospectively entered database for primary total hip arthroplasty. PATIENTS AND PARTICIPANTS: The prospective database was reviewed to extract all patients undergoing primary total hip replacement for complications of treatment of proximal femoral fractures. These fifty-three patients were then compared with fifty-three patients from the same data bank matched for age, sex, weight, prosthesis type, and length of follow-up but who had not sustained a proximal femoral fracture before total hip replacement. INTERVENTION: Primary total hip arthroplasty for complications of proximal femoral fractures. After the surgical procedure, patients were seen at follow-up intervals of three months and six months and, thereafter, yearly. MAIN OUTCOME MEASUREMENTS: Patients were evaluated using the St. Michael's hip rating scale, which is a scale measuring pain, motion, and function specifically designed for evaluation of total hip arthroplasty. Routine radiographs were obtained at each patient visit. RESULTS: The complications associated with total hip replacement in patients with previous proximal femoral fracture fixation occurred more frequently than in patients who had not had undergone previous fracture fixation; in addition, intraoperative surgical difficulty was significantly greater in those patients who had undergone previous surgery for hip fracture. However, the final hip score at > or = 2 years after total hip arthroplasty was not statistically different between the two patient groups. CONCLUSION: Total hip replacement is a satisfactory salvage procedure for failed fracture treatment despite the increased incidence of operative difficulty and increased incidence of complication.

Aged↗
PubMed1997

New renin inhibitors containing novel analogues of statine.

Solid-phase methodology has been used to synthesize a series of peptides based on the N-terminal sequence of human angiotensinogen in which statine (Sta) or the novel analogues (3S,4S)-3,4-diamino- or (3R,4S)-3,4-diamino-6-methylheptanoic acid (Ads or R-Ads) and (3S,4S)-4-amino-3-aminomethyl- or (3R,4S)-4-amino-3-aminomethyl-6-methylheptanoic acid (Amd or R-Amd) replace either residue 10 or both residues 10-11 at the P1-P1' cleavage site. The synthesis of these novel analogues of statine together with biological results on the inhibition of human and rat renin by peptides derived from them is reported. The absolute stereochemistry of the (3S,4S) Ads was determined by an X-ray crystallographic analysis of its N gamma-Boc, B beta-Z, R(+)-1-methyl benzamide derivative. Peptide Boc-His-Pro-Phe-His-Sta-Val-Ile-His-NH2 (VI) is the best inhibitor of human renin containing Sta at position 10. However, peptides containing Ads and Amd gave better rat renin inhibitors than the corresponding Sta-containing peptides. Peptides Boc-His-Pro-Phe-His-Ads-Val-Ile-His-NH2 (VII) having Ads at position 10 had an IC50 of 12 nM against rat renin. Although Sta has come to be accepted as an isosteric replacement for a dipeptide unit rather than for a single amino acid residue, in our series of inhibitors Sta is more effective when replacing only the amino acid at position 10 in the natural angiotensinogen sequence. None of the peptides gave any effect in vivo in a hypertensive rat model.

Amino Acid Sequence↗
PubMed1997

Prevalence of IgE-mediated allergy to latex in hospital nursing staff.

BACKGROUND: IgE-mediated hypersensitivity to latex proteins has become a significant clinical problem over the last decade. Nursing and medical staff are at risk because of their occupational exposure to latex. AIMS: To determine the prevalence of type I hypersensitivity to latex allergens in the nursing staff of an Australian hospital. METHODS: A questionnaire which asked about symptoms associated with the use of latex gloves was completed by 140 nurses working in the Alfred Hospital (72 in general medical wards, 68 in intensive care units). Skin prick tests with eluates of five different types of latex glove as well as common aeroallergens (rye pollen and house dust mite) and banana extract were performed. RESULTS: Thirty-one nurses (22%) were skin prick test positive to at least one of the five latex glove eluates. All of these nurses were atopic, having positive skin prick tests to rye pollen or house dust mite. Symptoms of local dryness, itch and erythema associated with glove use were reported by more than half the study group, but not more frequently by those who were skin prick test positive to latex. Urticaria associated with glove use was reported more frequently by those with positive latex skin prick tests (13% vs 4%, p = 0.05). Eighty-seven per cent of the nurses who were latex skin test positive were also positive to banana extract. CONCLUSIONS: IgE-mediated hypersensitivity to latex is common in nurses working in an Australian hospital. Glove associated symptoms were frequently reported, but in most cases the symptoms were more typical of irritant or contact dermatitis rather than type I hypersensitivity reactions. However, the extent of subclinical sensitisation to latex found in this study suggests that symptomatic latex allergy is likely to emerge as an increasing problem for nursing staff in this country.

Adult↗
PubMed1997

Factors influencing the outcome of donor marrow transplantation in adults from less than ideal donors: experience from two Australian centres.

BACKGROUND: This paper reports the results of 78 marrow transplants in two Australian hospitals between 1991 and 1996, using unrelated (n = 54) or mismatched related (n = 24) donors. Twenty-six patients received granulocyte-macrophage colony stimulating factor (GM-CSF) post-transplant as part of a phase II study. Fifty-four patients (74%) had advanced disease. AIMS: To identify factors associated with a superior outcome post-transplant, to evaluate the effect of GM-CSF on engraftment and other transplant parameters, and to compare the overall results with those of published series. METHODS: Review of patient records, a Medline search of the relevant literature and appropriate statistical analysis. RESULTS: The probability of overall survival and event-free survival (EFS) at three years was 35 +/- 6% and 22 +/- 6% respectively. Pre-transplant factors significantly associated with an inferior EFS were advanced disease, poorer performance status and age > 30 years. The EFS in patients with standard risk disease was 51 +/- 13% versus 10 +/- 5% in patients with advanced disease, p < 0.0001. Severe acute graft-versus-host disease was also associated with a poorer outcome. Neutrophil engraftment was faster in patients who received GM-CSF but there was no difference in any other transplant parameters. CONCLUSIONS: These results are consistent with reported series elsewhere and suggest that an extended family or unrelated donor transplant should generally be limited to patients with a good performance status and early phase but otherwise incurable haematological disease.

Acute Disease↗
PubMed1997

A short course of low-molecular-weight heparin to prevent deep venous thrombosis after elective total hip replacement.

OBJECTIVE: To determine the efficacy of a short course of low-molecular-weight heparin (enoxaparin) in the prevention of deep venous thrombosis and pulmonary embolism after elective total hip replacement. DESIGN: A prospective cohort study. Follow-up was a minimum of 3 months. SETTING: An acute-care hospital with a large-volume practice of elective total joint replacement. PATIENTS: A prospective group of 150 patients who required primary total hip arthroplasty and a historic control group of 150 patients. All patients were treated with compression stockings, indomethacin and early mobilization. The treatment group received low-molecular-weight heparin, 30 mg every 12 hours for 5 days postoperatively; the control group received no specific anticoagulant therapy. INTERVENTIONS: Total hip replacement. Doppler venography on postoperative day 5 and 2 to 5 days later if required. MAIN OUTCOME MEASURES: Presence or absence of deep venous thrombosis. Wound hemorrhage, transfusion rate, number of units of blood transfused and changes in the hemoglobin level. RESULTS: The incidence of proximal deep venous thrombosis (popliteal vein to common iliac vein) was 0% in the treatment group versus 4% in the control group. There was no difference in bleeding or number of transfusions required. There was, however, a significant (p = 0.005) drop in hemoglobin level in the treatment group. CONCLUSIONS: A short course of low-molecular-weight heparin provides effective protection against proximal deep venous thrombosis without significantly increasing the risk to the patient. The treatment is compatible with early patient discharge and the pharmacologic prevention of heterotopic ossification after total joint replacement.

Anticoagulants↗
PubMed1996

The serotonin transporter is a potential susceptibility factor for bipolar affective disorder.

The serotonin transporter is a strong candidate for aetiological involvement in affective disorders and psychosis. We analysed a VNTR in intron 2 of the human serotonin transporter gene (hSERT) for allelic association with bipolar affective disorder, unipolar depression and schizophrenia. An increased frequency of allele 12 of the VNTR was observed in subjects with bipolar affective disorder (n = 191; chi 2 p = 0.00048 by allele) but not unipolar depression (n = 86; chi 2 p = 0.18, ns) or schizophrenia (n = 129; chi 2 p = 0.08, ns), although a trend towards an excess of allele 12 was observed for the latter. There was also a significant difference in the frequency of allele 12 between bipolar affective disorder and unipolar depression (p = 0.0087). The relative risk for bipolar affective disorder with respect to allele 12 was 1.84 (95% CI 0.97-3.56) for heterozygotes, and 3.10 (95% CI 1.60-6.07) for homozygotes, with evidence for a gene-dosage effect. Because allele 12 is common in the population, the attributable risk is 50.8% (95% CI 14.5%-73.3%). We hypothesize that either the VNTR affects regulation of expression of hSERT at the transcriptional level or it is in linkage disequilibrium with another functional polymorphism in the gene, and this results in an increased risk for the development of bipolar affective disorder.

Alleles↗
PubMed1996

Short-term efficacy of ultrasonically nebulized hypertonic saline in cystic fibrosis.

Progressive lung disease in patients with cystic fibrosis (CF) is caused by thick secretions, which cause airway obstruction and subsequent colonization and infection by inhaled pathogenic microorganisms. Recently, recombinant human DNase has been shown to reduce the viscoelasticity of sputum in patients with cystic fibrosis and to improve lung function. Ultrasonically nebulized hypertonic saline (HS) has been demonstrated to enhance mucociliary clearance and sputum expectoration by rehydrating airway secretions, and may therefore provide a low cost alternative. We studied the changes in pulmonary function and symptoms in a group of patients with CF who have moderate to severe lung disease. The patients were evaluated following 2 weeks of treatment with HS in an open-label study. Subjects were randomly allocated to receive 10 ml of either 0.9% NaCl (IS) or 6% NaCl (HS). Twice daily, prior to physiotherapy, treatments were delivered by a portable ultrasonic nebulizer. To prevent bronchoconstriction, 600 mg of salbutamol was administered prior to the nebulized solutions. A symptom score was recorded and spirometry was performed on day 0 before therapy was started, on day 14 (the last day of therapy), and on day 28 (14 days after the last treatment with either IS or HS). Fifty-two patients (32 males), with a mean age of 16.2 (range 7-36) years completed the study. There was no difference in baseline characteristics between the two groups. Following 2 weeks of treatment, there was a significant improvement from baseline in FEV1 of 15.0 +/- 16.0% (mean +/- SD) in patients treated with HS, compared with a change of 2.8 +/- 13% in those on IS therapy (P = 0.004). Furthermore, there was a subjective improvement in the effectiveness of chest physiotherapy as reported by those using HS (P = 0.02). The treatment was well tolerated. We conclude that in patients with CF, ultrasonically nebulized hypertonic saline improves lung function in a way similar to that reported for human recombinant DNase when inhaled over a 2 week period. Nebulized saline also enhances the perception of effectiveness of chest physiotherapy.

Administration, Inhalation↗
PubMed1996

High response rates with short infusional 2-chlorodeoxyadenosine in de novo and relapsed low-grade lymphoma. Australian and New Zealand Lymphoma Study Group.

Thirty-five patients (eight de novo, 27 relapsed disease) with low-grade non-Hodgkin's lymphoma (diffuse small lymphocytic, follicular small cleaved cell, follicular mixed cell, and lymphoplasmacytoid) were treated with 2-chlorodeoxyadenosine (2CdA) at a daily dose of 0.14 mg/kg for 5d (2 h infusion) for an average of three cycles. Minor treatment delays, generally due to haematological toxicities, occurred in nine of 105 cycles. Major toxicities were lymphopenia, neutropenia and thrombocytopenia. Opportunistic infections occurred in seven patients. Overall response rate was 69% (five complete, 19 partial) reaching 88% for de novo patients (two complete, five partial). Elevated beta 2-microglobulin level was negatively predictive of response (P = 0.0014). Eight of 24 responders relapsed, with a median follow-up of 13 months. 2CdA administered as an intermittent infusion shows considerable single-agent activity in low-grade lymphomas achieving high response rates of prolonged duration. Consideration of schedules where 2CdA is alternatively administered with combination chemotherapy appears warranted.

Adult↗
PubMed1996

Is developmental dyslexia a disconnection syndrome? Evidence from PET scanning.

A rhyming and short-term memory task with visually presented letters were used to study brain activity in five compensated adult developmental dyslexics. Their only cognitive difficulty was in phonological processing, manifest in a wide range of tasks including spoonerisms, phonemic fluency and digit naming speed. PET scans showed that for the dyslexics, a subset only of the brain regions normally involved in phonological processing was activated: Broca's area during the rhyming task, temporo-parietal cortex during the short- term memory task. In contrast to normal controls these areas were not activated in concert. Furthermore the left insula was never activated. We propose that the defective phonological system of these dyslexics is due to weak connectivity between anterior and posterior language areas. This could be due to a dysfunctional left insula which may normally act as an anatomical bridge between Broca's area, superior temporal and inferior parietal cortex. The independent activation of the posterior and anterior speech areas in dyslexics supports the notion that representations of unsegmented and segmented phonology are functionally and anatomically separate.

Adult↗