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Biomedical subjects

D Price

Publications and source records attributed to D Price.

At least 109 records · Page 6Linked to original sources
PubMed1996

Selective effects of nerve growth factor on spatial recent memory as assessed by a delayed nonmatching-to-position task in the water maze.

Nerve growth factor (NGF) ameliorates age-related deficits in certain types of memory in rats. Although the effects of NGF on reference memory are well documented, the influence of NGF on recent memory is less well understood. The issue of recent memory is of primary importance in the design of therapies for cognitive disorders, because this type of memory is impaired in elderly humans and is severely affected early in the course of Alzheimer's disease (AD). The present study was designed to evaluate the efforts of NGF on recent memory in a task that used escape from water as the motivating stimulus and used the same design as forced-choice recognition tasks given to humans. Fischer-344 rats, 4 months old (4MO) or 23 months old (23MO), were pretested in a new spatial recent memory task designed for the Morris water maze, a delayed nonmatching-to-position task, and infused intraventricularly with recombinant human NGF or vehicle. After 2 weeks of NGF infusion, no substantial changes in behavior were observed in either age group. However, NGF treatment extended over 4 weeks improved considerably the choice accuracy of 23MO rats to a level similar to the performance of 4MO rats. These results, together with our previous work (Markowska et al., 1994), indicate that the effects of NGF on spatial recent memory are more intense than on spatial reference memory. NGF suppressed the body weight gain in 4MO rats but did not affect 23MO rats. In 23MO rats, NGF mildly counteracted age-related deficits in inhibitory avoidance, but did not have an effect in young rats.

Aging↗
PubMed1996

Lessons for health care rationing from the case of child B.

More details have emerged about the child B leukaemia case with the publication of the All England Law Report on the Appeal Court decision. At the time the view was widely held that the controversy might have been avoided if the responsible health authority had consulted the public. The law report reveals, however, that the courts adopted a moral language widely at variance with that of the patient's doctor. The courts were concerned to support a utilitarian decision procedure based on calculations of the greatest overall good; the doctor was concerned with the best interests of a sick child. The doctor-patient relationship may be damaged when public consideration transforms the issue in this way. Also, the Appeal Court supported a decision which claimed to have "weighed" opposing evaluations, but it excused the health authority from describing how that weighing took place. One of the main criticisms of the utilitarian approach, however, is that weighing of this type is extremely difficult to justify. By its ruling the court has made legal challenge on the grounds of inadequate consultation virtually impossible to substantiate.

Child↗
PubMed1996

Radiological features of a symptomatic splenic hamartoma.

Symptomatic splenic hamartomas are rare in the pediatric age group, with only four previous reports in the literature. Splenic hamartoma has been reported as a solid homogeneous mass without calcification on CT and ultrasound (US), and only one previous report of the findings on MRI has been published. We report a case of a large symptomatic splenic hamartoma in a 14-year-old girl who presented with splenomegaly, pancytopenia and growth retardation. A solid mass with multiple punctate foci resembling calcifications was seen on US. The mass was heterogeneous and better demarcated on enhanced CT. Radiocolloid scintigraphy demonstrated uptake within the lesion, but less than that of normal spleen. The mass was isointense relative to normal splenic tissue on T1-weighted MRI (0.5 T) and of increased intensity with T2 weighting. At splenectomy, a red pulp hamartoma was identified, which contained nodules of hyalinization and necrosis thought to account for the punctate foci seen on US.

Adolescent↗
PubMed1996

MR of the pituitary in patients with Prader-Willi syndrome: size determination and imaging findings.

Prader-Willi syndrome (PWS) is an unusual genetic disorder characterized by short stature, obesity, hypogonadism, hypotonia, cognitive impairment, and dysmorphic facies. There is an interstitial deletion of the proximal long arm of chromosome 15 in about 70 % of patients. Some of these clinical features suggest a central hypothalamic/pituitary dysfunction, and recent investigations have demonstrated a marked impairment in spontaneous growth hormone (GH) secretion. We studied 15 GH-deficient PWS patients by magnetic resonance imaging (MRI) to determine whether there was a diminution in the gross morphological size of the anterior pituitary gland, the site of GH synthesis. We also set out to catalog the pertinent imaging findings in this patient population. Our results indicate that this is the first report documenting pituitary size by MRI in PWS patients. No statistically significant difference was found in the height of the anterior pituitary gland in PWS patients compared with either normal children or children with isolated GH deficiency. An interesting imaging finding is that three of 15 patients (20 %) demonstrated complete absence of the posterior pituitary bright spot (PPBS), and a fourth patient demonstrated a small PPBS. These observations reflect an objective physiologic disturbance in the hypothalamus. The clinical and radiologic implications of these findings are discussed.

Adolescent↗
PubMed1996

Oligomers in plastics packaging. Part 1: Migration tests for vinyl chloride tetramer.

Vinyl chloride (VC) tetramer has been studied as a representative oligomer that has the potential for migration from plastics packaging. Poly(vinyl chloride) (PVC) bottles for retail beverages were analysed by a process of dissolution followed by gas chromatography. Tetramer levels ranged from 70 to 190 mg/kg in the plastic. When these bottles were tested for migration into the simulants distilled water, 3% acetic acid, 15% ethanol and olive oil, no tetramer migration was detected at a limit of 5-10 micrograms/kg. Since, of the low molecular weight oligomers, the tetramer had the highest concentration in the PVC plastics, it is concluded that the other VC oligomers of higher molecular weight, would not migrate above this limit of detection either.

Acetates↗
PubMed1996

Ruralising the undergraduate medical curriculum through consultation with key stake holders.

This paper describes the approach taken at the University of Queensland to broaden the scope of curriculum design to involve rural general practitioners, medical students and rural health care consumers. A form of nominal group process in serial telephone teleconferences was used, with a group of rural general practitioners, to develop and pilot curriculum content, learning strategies and assessment methods. Medical students assisted in the evaluation of the curriculum and representatives of rural organisations were consulted about the value of hosting medical students in rural communities. The three groups made significant contributions to the project. The results will be trialed for the entire year 6 cohort (240 students) in 1995 and will form the basis of the planned rural practice term in the new graduate course.

Community Participation↗
PubMed1996

Collaboration in curriculum design: preparing educational programs for Australian rural medical practitioners.

Details of the process used by the authors, as curriculum design consultants, for the Rural Medicine Curriculum Design Project are presented. The process resulted in separate curricula in surgery, anaesthesia and obstetrics for use in advanced training within the Rural Training Program of the Faculty of Rural Medicine of the Royal Australian College of General Practitioners (RACGP). Key features of the design process are synthesised as a guide to projects where agreement across divergent groups is essential.

Anesthesiology↗
PubMed1996

Complement C6 and C7 DNA polymorphisms analysed by PCR in seven ethnic groups and characterisation of the C6 MspI RFLP.

Five polymorphisms in the C6 and C7 genes have been investigated in seven ethnic groups. The allele frequencies are broadly similar in most groups except C7 M/N which is monomorphic in our group of Africans, and C6 MspI and C7 S367T where the allele frequencies in African and Cape Coloured subjects are very different from the other ethnic groups. There is very little allelic association except between C6 A/B and C6 MspI. Seventeen of the 32 possible haplotypes have been observed, suggesting that much recombination has taken place. We describe a new method for the investigation of the MspI RFLP located in intron 3 of C6 (approximately 3 kbp 3' from exon 3 and 1.5 kbp 5' from exon 4) and its molecular basis, together with an improved method for the isolation of DNA from stored serum.

Alleles↗
PubMed1995

The MATK tyrosine kinase interacts in a specific and SH2-dependent manner with c-Kit.

We have cloned a protein tyrosine kinase, MATK, which is expressed abundantly in megakaryocytes and the brain. We investigated whether MATK participates in the c-Kit ligand/stem cell factor (KL/SCF) signaling pathway in the megakaryocytic cell line CMK. After KL/SCF stimulation, five major proteins of molecular masses of 145, 113, 92, 76, and 63 kDa were rapidly and transiently tyrosine-phosphorylated in a time-dependent manner, peaking within 5 min, and returning to basal levels within 60 min. To study the role of MATK in the KL/SCF signaling pathway, glutathione S-transferase (GST) fusion proteins containing SH2 and SH3 domains of MATK were cloned, expressed in Escherichia coli, and purified. MATK-SH2, but not MATK-SH3, precipitated the tyrosine-phosphorylated c-Kit (molecular mass of 145 kDa) in KL/SCF-stimulated CMK cells. Other GST fusion proteins containing the SH2 domain of p85 of phosphatidylinositol 3-kinase, phospholipase C gamma-1, and ras-GAP also precipitated c-Kit. The tyrosine-phosphorylated c-Kit was co-immunoprecipitated with anti-MATK and anti-p85 antibodies in KL/SCF-stimulated CMK cells, but not in granulocyte-macrophage colony stimulating factor or interleukin-6-stimulated cells, suggesting receptor specificity. These results indicate that MATK associates with the c-Kit receptor following specific stimulation by KL/SCF via its SH2 domain and likely participates in transduction of growth signals induced by this cytokine in megakaryocytes.

GTPase-Activating Proteins↗
PubMed1995

Age-related CNS disorder and early death in transgenic FVB/N mice overexpressing Alzheimer amyloid precursor proteins.

Transgenic FVB/N mice overexpressing human (Hu) or mouse (Mo) Alzheimer amyloid precursor protein (APP695) die early and develop a CNS disorder that includes neophobia and impaired spatial alternation, with diminished glucose utilization and astrogliosis mainly in the cerebrum. Age at onset of neophobia and age at death decrease with increasing levels of brain APP. HuAPP transgenes induce death much earlier than MoAPP transgenes expressed at similar levels. No extracellular amyloid was detected, indicating that some deleterious processes related to APP overexpression are dissociated from formation of amyloid. A similar clinical syndrome occurs spontaneously in approximately 20% of nontransgenic mice when they reach mid- to late-adult life, suggesting that APP overexpression may accelerate a naturally occurring age-related CNS disorder in FVB/N mice.

Aging↗
PubMed1995

Abnormal intraepithelial airway nerves in persistent unexplained cough?

Idiopathic persistent nonproductive cough (PNPC) is characterized by enhanced cough sensitivity to inhaled capsaicin, suggesting that capsaicin-sensitive afferent airway nerves are either present in increased numbers or functionally upregulated. In 16 patients with idiopathic PNPC and eight healthy control subjects, we measured cough sensitivity to inhaled capsaicin and the anatomic density in bronchial epithelium of nerves immunoreactive for the general nerve-marker protein gene product (PGP)-9.5 and the sensory neuropeptides calcitonin-gene-related-peptide (CGRP) and substance-P (SP). The log concentrations of capsaicin required to elicit at least two (C2) and five (C5) coughs were significantly lower in patients (P) than in control subjects (C) (median [range] log C2, P = 0.3 [-0.3 to 1.2] microM; C = 1.5 [0.9 to 2.1], p < 0.0005; log C5, P = 0.8 [-0.3 to 2.1]; C = 2.6 [1.8 to 3.0], p < 0.0005). In bronchial epithelium taken from the carina of the right upper lobe (RUL) and a subsegmental carina of the right lower lobe (RLL), total nerve density (PGP-9.5 immunoreactivity) was greater in P than C, although this was not significant. CGRP-immunoreactive nerve density was significantly higher in P than in C in the RUL (median [range] P = 1.05% [0.13 to 5.08]; C = 0.02% [0 to 0.24], p = 0.001) and RLL (P = 0.59% [0.04 to 3.14]; C = 0% [0 to 0.50], p < 0.02). SP-immunoreactive nerves were not significantly different in the two groups. Abnormal intraepithelial airway nerves containing increased quantities of CGRP are present in patients with idiopathic PNPC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Diffuse idiopathic skeletal hyperostosis (DISH): a review of radiographic features and report of four cases.

OBJECTIVE: To discuss the diagnostic criteria, clinical findings and radiographic findings of diffuse idiopathic skeletal hyperostosis (DISH). CLINICAL FEATURES: DISH is a disease that affects elderly persons and is characterized by a bone-forming tendency with prominent radiographic findings, including proliferation of bone throughout the ligaments and tendons of the spine and extremities. Clinical symptoms are often mild and include mild pain and stiffness. DISH can coexist with other articular diseases, such as degenerative joint disease and rheumatoid arthritis, or can be complicated with myelopathy and fracture. INTERVENTION AND OUTCOME: All four patients were men over the age of 75 and had DISH with associated neurological signs and symptoms. Three patients showed improvement after chiropractic manipulative treatment. One patient was referred for a surgical consultation for atlantoaxial instability from rheumatoid arthritis and was subsequently lost to follow-up. CONCLUSION: DISH is a common disease of the elderly; clinicians should recognize its radiographic and diagnostic features.

Aged↗