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Biomedical subjects

G M Murphy

Publications and source records attributed to G M Murphy.

At least 145 records · Page 8Linked to original sources
PubMed1994

Neurotropic ulceration in systemic sclerosis.

Scleroderma is primarily a cutaneous disorder but systemic involvement is common and neurological complications are increasingly recognized but previously poorly documented. Few cases of peripheral nervous system involvement in scleroderma have been reported. The peripheral nervous system, however, is rich in connective tissue and sclerodermal involvement may not be as unusual as the literature suggests. A case in which there was a mixed sensorimotor peripheral neuropathy with neurotropic ulceration in a patient with systemic sclerosis is reported.

Foot Ulcer↗
PubMed1994

Measurement of androgen receptor expression in adult liver, fetal liver, and Hep-G2 cells by the polymerase chain reaction.

Hepatocellular carcinoma is the most commonly fatal malignant tumour worldwide. The role of androgen receptors, which have been found in hepatocellular carcinoma, is controversial. Sequence specific polymerase chain reaction (PCR) was used to quantify, for the first time, the expression of androgen receptor in four adult liver biopsy specimens (HL-A to HL-D), fetal liver, and Hep-G2 cells. The measurement of androgen receptor is expressed as a ratio (androgen receptor: beta-actin) of the value of androgen receptor to the value of a control gene, beta-actin. The value of the androgen receptor: beta-actin ratios for HL-A, HL-B, HL-C, HL-D, fetal liver, and Hep-G2 were 0.37, 0.86, 0.37, 0.44, 0.87, and 0.66 respectively. To verify sequence specific amplification of the androgen receptor, the PCR androgen receptor fragment was sequenced. The resultant sequence data for both strands of the double stranded PCR androgen receptor fragment had 100% similarity with the published androgen receptor mRNA sequence (complete codons).

Actins↗
PubMed1994

Aging and the nigrostriatal dopamine system: a non-human primate study.

The present study examined neurochemical, morphological and functional markers of the nigrostriatal dopamine system in young, intermediate-aged and old squirrel monkeys. Striking reductions in motoric activity were observed with advancing age. significant age-related loss of dopamine occurred in the substantia nigra (70%) and the putamen (30%) but not in the caudate. There was a strong correlation between the reductions in motoric activity and the loss of putamen dopamine. However, nigrostriatal dopamine loss did not appear to be the consequence of age-related loss of dopaminergic nigral neurons since the number of tyrosine immunoreactive cells was not significantly different among the three age groups. These results suggest that the aging squirrel monkey demonstrates the age-related loss of nigrostriatal dopamine thought to occur in humans and identify this non-human primate as a useful model to further investigate the underlying mechanism(s) and functional consequences of age-related decline of the nigrostriatal dopamine system. In addition, the selective loss of dopamine in the putamen but not the caudate parallels the regional vulnerability observed in Parkinson's disease, an age-related neurodegenerative disorder, raising the possibility of a relationship between normal aging and the development of this disease. Finally, because the number of tyrosine hydroxylase (TH) positive cells remains constant with age, these results raise the possibility that therapeutic strategies aimed at increasing dopamine concentrations may benefit elderly individuals.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Development of a monoclonal antibody specific for the COOH-terminal of beta-amyloid 1-42 and its immunohistochemical reactivity in Alzheimer's disease and related disorders.

The beta-amyloid peptide (beta AP) has been characterized by protein sequencing techniques as a 39-43 amino acid protein with heterogeneous COOH-termini. Controversy exists regarding the predominant form of beta AP in neuritic plaques (NP) and cerebral vasculature of Alzheimer's disease (AD) brain. A monoclonal antibody was developed that selectively recognizes the free COOH-terminal of beta AP 1-42 but not beta AP species with shorter or longer COOH-termini. Brain sections from AD and related disorders were examined using this antibody. In AD samples, the antibody stained diffuse amyloid and NP cores, many intraneuronal and extraneuronal neurofibrillary tangles (NFT), but not cerebrovascular amyloid. Pick and Lewy bodies lacked immunoreactivity. These findings suggest that beta AP 1-42 is present in early and mature amyloid deposits and NFT, but that species of beta AP other than 1-42 comprise human vascular deposits.

Adult↗
PubMed1993

Reverse transcription and polymerase chain reaction technique for quantification of mRNA in primary astrocyte cultures.

The reverse transcription and polymerase chain reaction technique (RT-PCR) was assessed for the quantification of changes in mRNA levels from primary astrocyte cultures. The effects of dibutyryl cyclic AMP (dBcAMP) on glial fibrillary acidic protein (GFAP) mRNA and the effects of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and lipopolysaccharide (LPS) on interleukin-6 (IL-6) mRNA were examined. Two quantitative PCR methods were used: one involved carrying out the reaction in the exponential phase and the other involved the coamplification of a competitive target sequence. Increased GFAP mRNA in response to chronic dBcAMP treatment and increased IL-6 mRNA in response to TNF-alpha/IL-1 beta were readily detected. Both RT-PCR techniques were found to be suitable for the detection of large as well as smaller (twofold) changes in mRNA levels. The advantages and limitations of RT-PCR for mRNA quantification are discussed.

Animals↗
PubMed1993

Detection of latent variegate porphyria by fluorescence emission spectroscopy of plasma.

The plasma of patients with overt variegate porphyria contains porphyrin with a fluorescence emission maximum at about 626 nm, which is diagnostic for the condition. We have evaluated qualitative fluorescence emission scanning of saline-diluted plasma as a method for the identification of asymptomatic carriers of the gene for variegate porphyria. Plasma from 36 unrelated patients with variegate porphyria, 136 of their asymptomatic first- and second-degree relatives aged 15 years or over, and 322 normal subjects was scanned. An emission maximum between 621 and 627 nm was observed in the 36 patients with variegate porphyria and 54 of their relatives, but not in any normal subject, nor in 56 patients with other types of porphyria. For the detection of asymptomatic adult carriers of the gene for variegate porphyria, fluorescence emission scanning of plasma appears to be 100% specific, with a sensitivity of 86% (95% confidence interval 71-98%). In contrast, the sensitivity of faecal porphyrin analysis as a test for adult gene carriers was 36%. These results suggest that fluorescence emission scanning of plasma should replace faecal porphyrin analysis as the test of first choice for this purpose.

Adolescent↗
PubMed1993

Low-dose ultraviolet-B irradiation depletes human epidermal Langerhans cells.

We have examined the effects of low-dose monochromatic UVB irradiation (295 +/- 5 nm), biologically equivalent to that generally incident on the skin during a 12-session sun-bed course, on the expression of the CD1a epidermal Langerhans cell surface marker in human skin in vivo. In five subjects, 1.5 minimal erythema doses (MEDs) at 295 nm depleted its expression by 50%. In five further subjects, a single 1.5 MED dose, 1.5 MEDs in 10 equal fractions on alternate days, and a single 1.5 MED dose at one-tenth the previously used irradiance, delivered to separate sites, also led to variable but significant depletion of CD1a expression of around 30-50%. Thus, low-dose UVB irradiation, whether received rapidly or slowly, appears significantly and approximately equally to deplete human epidermal Langerhans cell numbers as measured by CD1a expression.

Antigens, CD↗
PubMed1993

Determination of threshold UV-A elicitation dose in photopatch testing.

Photopatch testing, although widely used in the diagnosis of photosensitivity disorders, is not standardized. We performed this study to determine the threshold ultraviolet light A (UV-A) dose required to elicit photopatch test responses. 4 patients with previously positive tests were reexposed to the offending allergen, using an incremental dosage regime. Isopropyl dibenzoylmethane (Eusolex 8020), mexenone (benzophenone-10) and oxybenzone (benzophenone-3) produced positive responses at 1.0, 1.0 and 0.7 J/cm2, respectively. Responses to phenothiazines were deemed phototoxic. These results demonstrate that high doses of UV-A (e.g., 10-15 J/cm2) are unnecessary, and that 5 J/cm2 should become the current standard.

Adult↗
PubMed1993

Phosphorus supplements and fluorosis in cattle--a northern Australian experience.

Chronic fluoride toxicosis caused lameness, dental lesions and illthrift in an extensive beef cattle herd in northern Australia. Up to 15% of the herd was lame and the disease forced the culling of large numbers of cows. The source of fluoride was fertiliser-grade monoammonium and diammonium phosphate fed as part of a mineral supplement. Large quantities of mineral supplement were provided to the cattle because lameness was attributed to phosphorus deficiency, which is endemic in the area. Most lameness developed in the late dry season in the post-lactation phase. Severe lameness was caused by fractured pedal bones.

Animals↗
PubMed1992

Nuclear magnetic resonance spectroscopy to determine the micellar cholesterol in human bile.

The cholesterol of gallstones comes from the vesicular rather than the micellar phase of bile. Progress in this field has been limited because conventional analytical methods disturb the distribution of cholesterol between the two phases. The resonance of the cholesterol C6 proton occurs at a chemical shift of 5.4 ppm, to be shown by 2D NMR to be specific for biliary cholesterol, and arises only from the micellar mode. Thus integration of the C6 proton resonance peak area provides a direct non-invasive determination of the cholesterol distribution in human bile.

Bile↗
PubMed1992

Lichen planus associated with chenodeoxycholic acid and ursodeoxycholic acid for gallstone dissolution.

A patient who developed lichen planus while receiving chenodeoxycholic acid and ursodeoxycholic acid therapy for gallstones is described. Skin biopsy was performed and histological examination suggested a drug etiology. An association between lichen planus and liver disease is recognized, but this patient exhibited no clinical or biochemical evidence of liver disease and the rash disappeared after cessation of the bile acid therapy. Bile acids may cause lichen planus. The mechanism is unknown.

Aged↗