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R N Butler

Publications and source records attributed to R N Butler.

At least 109 records · Page 6Linked to original sources
PubMed1993

Immunobead-PCR: a technique for the detection of circulating tumor cells using immunomagnetic beads and the polymerase chain reaction.

The presence of tumor cells in the circulation may predict disease recurrence and metastases. We have developed a sensitive technique for the detection of carcinoma cells in blood, using immunomagnetic beads to enrich for epithelial cells and the polymerase chain reaction to identify a tumor marker. The colon carcinoma cell line SW480, homozygous for a K-ras codon 12 mutation, was used to establish optimal conditions. The SW480 cells were serially diluted in normal blood and incubated with immunomagnetic beads labeled with a monoclonal antibody specific for epithelial cells. Cells bound to the beads were retrieved using a magnetic field and the presence of K-ras codon 12 mutations determined by a polymerase chain reaction based analysis. SW480 cells could be detected in dilutions up to 1 SW480 cell/10(5) leukocytes in whole blood.

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PubMed1993

Effect of dehydroepiandrosterone on pentose phosphate pathway activity in the rat colon.

1. The effects of fasting and fasting followed by refeeding on the activities of the oxidative pentose pathway (OPP) and the non-oxidative pentose pathway (NOPP) were estimated by the rate of production of 14CO2 from [1-14C] glucose in isolated rat colonocytes, and the production of hexose 6-phosphates from ribose 5-phosphate in rat colonic cytosols, respectively. 2. The OPP activity in colonocytes from rats in the fasted state was 50% lower when compared to colonocytes from rats refed after a fast. This indicated induction of the rate-limiting enzyme of the OPP, glucose 6-P dehydrogenase (G6-PDH) in the latter instance. No effect on the maximal catalytic activity of the enzymes of the NOPP was seen in colonocytes from rats refed after a fast compared with colonocytes from rats in the fasted state. 3. Isolated colonocytes obtained from the distal colon of rats refed after a fast, showed a significant decrease (30%) in OPP activity when incubated with 50 microM dehydroepiandrosterone (DHEA). A similar degree of inhibition was seen with 10 mM butyrate (P < 0.05). In contrast, using colonic cytosols, both DHEA and butyrate had no effect on the maximal catalytic activity of the NOPP. 4. Intraperitoneal injection (i.p.) of DHEA in rats refed after a fast showed a significant increase in the maximal catalytic activity of the NOPP in the distal colon (46%; P < 0.05). A similar elevation in the maximal catalytic activity of the NOPP was seen in the distal colon of DHEA treated pair-fed rats (43%; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1993

Vascular dementia: stroke prevention takes on new urgency.

Vascular dementia is a clinical syndrome of acquired intellectual impairment resulting from brain injury due to a cerebrovascular disorder. It is a complex diagnosis, and diagnostic criteria vary. In community practice, the physician can probably make the diagnosis based on the history and medical examination. CT demonstration of one or more infarcts increases the likelihood of this diagnosis. Hypertension is a major risk factor for vascular dementia. Others include smoking, hyperlipidemia, atrial fibrillation, diabetes, and a sedentary lifestyle. Cerebrovascular disease is an important cause of cognitive decline in older patients. Therefore, it is important to recognize risk factors for stroke and institute measures for prevention.

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PubMed1993

Vascular dementia: how to make the diagnosis in office practice.

Vascular dementia is seen much more often in people at age 85 than in those between the ages of 55 and 75. The differential diagnosis includes Alzheimer's disease and mixed dementia. The classic criteria for vascular dementia--stepwise deterioration and focal neurologic signs--are important, as focal neurologic signs usually don't occur in Alzheimer's disease. Identifying a significant number of points on the Hachinski scale, including hypertension, can help make a diagnosis of vascular disease. For more effective differential diagnosis, CT or MRI can be useful. However, not all clinicians are convinced of the necessity of imaging, as long as stroke risk factors such as hypertension and hyperlipidemia are managed for all older patients.

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