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D Parkinson

Publications and source records attributed to D Parkinson.

At least 37 records · Page 2Linked to original sources
PubMed1998

A perspective on the clinical effectiveness and tolerance of interferon-alpha.

Interferons (IFNs) are potent biologic response modifiers with antiviral and antiproliferative effects. The successful clinical application of IFNs for the treatment of chronic viral infections and malignancies has resulted in improved quality and quantity of life for thousands of patients, and the number of new indications for IFN therapy continues to grow. However, the therapeutic effectiveness of IFNs, including IFN-alpha, is often compromised by a variety of dose-related side effects that can be dose limiting. These side effects include flu-like symptoms, fatigue, anorexia, and depression, which may be mild or severe. A better understanding of the mechanisms by which IFN-alpha causes these side effects will facilitate the development of effective strategies to lessen their effects on the patient's quality of life and allow the maximum therapeutic dose of IFN-alpha to be administered.

Humans↗
PubMed1997

Melanosis coli is associated with an increase in colonic epithelial apoptosis and not with laxative use.

We have investigated the clinical presentation, laxative use and histopathology of 38 patients with a histological diagnosis of melanosis coli and measured the colonic epithelial apoptosis in these cases. The presence of lipofuscin was confirmed in all cases. Fifteen of the cases had constipation, whilst eight had diarrhoea. Neither constipation nor diarrhoea was present in 13 cases and both were present, at different times, in two. Laxatives had been used in all those with constipation, in only one with diarrhoea and in none of the others. The mean apoptotic count was significantly increased in those with melanosis coli compared with the controls. In the majority of cases with constipation there was no other abnormality, whilst an additional diagnosis was present in the majority of the remainder. Colonic epithelial apoptosis was increased in melanosis coli and the majority of cases were not associated with laxative use. These results support the proposed role of apoptosis in melanosis coli, but indicate that melanosis coli is a non-specific marker of increased apoptosis with many possible causes, of which the use of laxatives is only one.

Adolescent↗
PubMed1997

MPTP induces dystonia and parkinsonism. Clues to the pathophysiology of dystonia.

The pathophysiology of dystonia is unclear, but several clues implicate striatal dopamine dysfunction. In contrast, the causal relationship between striatal dopamine deficiency and parkinsonism is well defined. We now suggest that parkinsonism or dystonia may occur following striatal dopamine deficiency. Baboons treated with intracarotid 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) developed transient hemidystonia prior to hemiparkinsonism. The day after MPTP treatment, most animals had spontaneous ipsilateral turning. Within a few days, all developed contralateral hemidystonia, with the arm and leg extended and externally rotated. This transient dystonia preceded hemiparkinsonism with flexed posture, bradykinesia, and postural tremor that persisted for up to 1.5 years. Dystonia corresponded temporally with a decreased striatal dopamine content and a transient decrease in D2-like receptor number. The time course of dystonia and parkinsonism is analogous to lower limb dystonia as the first, frequently transient, symptom of Parkinson's disease in humans. The association of striatal dopamine deficiency with dystonia and parkinsonism implies that other factors influence clinical manifestations.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1996

Posterior "septum" of human spinal cord: normal developmental variations, composition, and terminology.

BACKGROUND: The boundary separating the posterior columns of the spinal cord is formed by the lateral margins of the neural groove approximating to form the neural canal. In anatomy texts this line is usually drawn as continuous, uniform, centered, and straight. It is universally termed posterior or dorsal, median "septum". METHODS: Sections from the cervical and lumbar enlargements and the mid-thoracic region were examined from 35 human autopsy specimens from 20 weeks gestation to 70 years with no history of spinal cord disease or trauma. They were stained with Masson's trichrome, and by immunohistochemistry for collagen types 1 and 4, and for glial fibrillary acidic protein (GFAP). RESULTS: One or more variations were found in the position character, shape, or extent of the line at one or more levels in every case. There was no midline staining for collagen other than that associated with blood vessels. There is intense immunoreactivity for GFAP from 20 weeks gestation to 35 weeks diminishing thereafter. When the posterior columns are separated the "septum" divides. CONCLUSION: In the absence of any collagen this line of separation is more akin to a raphé than a septum. Inasmuch as there is an immediately adjacent subarachnoid posterior median septum it would be advantageous to re-name this intraspinal structure "dorsal" or "posterior" median raphé.

Adolescent↗
PubMed1996

Evaluating cerebral concussion.

Years ago we developed a rat model that was consistently comatose for 1-2 seconds following 50 G acceleration of the head. Motor normalcy returned in about 10 seconds, and normal memory in an hour. There were immediate electroencephalogram and transmitter changes. All these returned to normal within an hour following 1 or 20 such concussions. We could find no light or electron microscopic changes. Halothane anesthesia precludes measurement of coma and introduces distortion of metabolite findings. To date our findings indicated concussion at this level is completely reversible.

Animals↗
PubMed1996

Neurochemical effects of static magnetic field exposure.

BACKGROUND: There has been considerable interest in both the lay and scientific media concerning the putative effects of exposure to electromagnetic fields. An assessment of the effects of static magnet exposure on neurochemistry was undertaken to determine potential risks to patients and staff involved with magnetic resonance imaging and spectroscopy. METHODS: One set of rats were exposed to weak static field (800 gauss [G]) in an otherwise normal laboratory surrounding. Another set of rats were exposed to 7-Tesla fields, both with suitable controls. RESULTS: Exposure of rats (n=8) to weak static fields for periods between 12 hours and 8 days produced no significant change in nighttime pineal or serum melatonin levels, as compared to controls, nor did it significantly influence levels of pontine medullary 5-hydroxytryptamine [5-HT] and hypothalamic 5-hydroxyindoleacetic acid [5-HIAA]. Placing rats in a 7-Tesla MRI magnet for 45 minutes produced similar results. CONCLUSIONS: These experiments suggest that daily light/dark cycle has much greater influence on levels of melatonin, catecholamines, serotonin, or their metabolites than does exposure to a static magnetic field.

Animals↗
PubMed1996

Three dimensional comparison of blocked arcs vs. four and six field conformal treatment of the prostate.

PURPOSE: The purpose of this study is to compare five different techniques for treatment the prostate without seminal vesicles. Dose volume histograms and a time survey are the tools that were used for this analysis. METHODS AND MATERIALS: For this study we compared 3D techniques using four and six field conformal treatments, to open and blocked 8 x 8 cm2 120 degrees bilateral arcs. All the plans were normalized to deliver 100% to the central axis, and full 3D calculations were performed. Blocked arcs were created using the 'average beam's eye view' (A-BEV) technique. RESULTS: Analysis of the dose volume histograms revealed: (1) Arcs with blocks result in an improved dose distribution compared to standard arcs and four field 3DCRT techniques, (2) The DVH associated with blocked arcs, using block margins of 1.3 cm, resulted in a somewhat lower dose to the rectum but a 'tighter' margin around the prostate compared to the DVH generated using the six field 3DCRT technique. CONCLUSION: This technique is for treatment of the prostate only, when treatment of the seminal vesicle is not required. The use of blocked arcs significantly improved the dose distribution compared to using standard arcs and 4-field conformal techniques. The DVHs associated with using blocked arcs is comparable to the SFC technique. It is likely to be less expensive, faster to set-up and may allow for safe dose escalation when only the prostate is receiving treatment.

Humans↗
PubMed1996

Membranous fat necrosis of the breast.

To investigate the pattern and prevalence of membranous fat necrosis of the breast we examined 25 breast biopsies or mastectomy specimens performed for recurrent lumps following conservative surgery and radiation therapy. In addition, we examined 41 consecutive cases taken from our files coded as fat necrosis which were associated with several aetiologies. Our results demonstrate that membranous fat necrosis of the breast occurs in association with several aetiologies but in its florid form is most often due to radiation therapy.

Adipocytes↗
PubMed1996

Identification of MYCN Copy Number Heterogeneity by Direct FISH Analysis of Neuroblastoma Preparations.

Background: Amplification of MYCN and deletion of 1p in neuroblastoma are associated wtih a poor prognosis. MYCN copy numbers of 10 or greater are considered to be indicative of poor outcome. However, most molecular genetic methods for estimating the number of MYCN genes do not directly address copy number heterogeneity at the cellular level. Methods and Results: MYCN copy number was assessed by fluorescence in situ hybridization (FISH), differential polymerase chain reaction (PCR), and Southern blot analysis, using 29 patient tumors. Copy number estimates by PCR or Southern blot analyses identified MYCN amplification in 11 tumors. There was complete concordance between FISH MYCN results in all 11 tumors with amplification. FISH identified 5 tumors with marked heterogeneity for MYCN copy number. Two tumors in which a small percentage of cells within the specimen were amplified would have gone undetected by molecular genetic methods alone. Conclusions: FISH offers the advantage over the other methods of detecting heterogeneity, thereby revealing tumors with small numbers of amplified cells that would otherwise be missed and, in cases of low (3-10) copies of MYCN, distinguishing small numbers of amplified cells (poor prognosis) from triploid tumors (good prognosis). FISH also allows detection of 1p deletion using the same preparations, which represents another advantage. A combination of FISH and conventional molecular methods provides an accurate definition of sample heterogeneity, and should be routinely applied to all neuroblastomas with low levels of MYCN copy number.

Journal Article↗