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Biomedical subjects

J Simpson

Publications and source records attributed to J Simpson.

At least 307 records · Page 17Linked to original sources
PubMed1985

Light-inducible and tissue-specific expression of a chimaeric gene under control of the 5'-flanking sequence of a pea chlorophyll a/b-binding protein gene.

We have investigated the regulatory functions of the 5'-flanking sequences of a chlorophyll a/b-binding protein gene from Pisum sativum, using the neomycin phosphotransferase (II) activity from Tn5 as an enzymatic reporter. We show that 0.4 kb of the upstream flanking sequences of this gene are sufficient for both organ-specific and light-regulated expression of our chimaeric constructs in transformed tobacco plants. In addition, we show that sequences farther upstream have a significant influence on the level of transcription of these constructions.

Journal Article↗
PubMed1985

Biochemical studies on rabbits with aluminium induced neurofilament accumulations.

The activities of acid phosphatase, hexosaminidase, beta-galactosidase, Mg2+-stimulated Na+K+ATPase, fumarase and ATP:citrate lyase were measured in grey matter of rabbit spinal cord 7-8 days after intra-ventricular or intra-cisternal injection of aluminium. RNA, DNA, and water content were measured in whole spinal cords. Choline acetyltransferase (CAT) and acetylcholinesterase were assayed in dorsal grey matter of the cord, which contained no aluminium-induced neurofilament accumulations (NFAs), and ventral grey matter, which had large numbers of such NFAs. CAT was also assayed in the hypoglossal nerve. None of these measures were consistently altered in the aluminium treated rabbits, although the activity of beta-galactosidase was increased in the NFA-free caudate nucleus of rabbits given aluminium intra-ventricularly, possibly due to the presence of phagocytes on the ventricular surface of the caudate. It is concluded that neither aluminium nor its induced NFAs has a gross effect on neuronal metabolism within 7-8 days.

ATP Citrate (pro-S)-Lyase↗
PubMed1985

Toxicity of the mycotoxin patulin for rat alveolar macrophages.

Agricultural workers are exposed to a variety of organic dusts containing fungi and their secondary metabolites. Patulin, a polyketide lactone mycotoxin produced by several common species of Aspergillus and Penicillium, is found in corn silage. Patulin is toxic in experimental animals and has been reported to be mutagenic, teratogenic, and carcinogenic. The cytotoxicity of patulin was studied in rat alveolar macrophages in vitro. The effects of patulin on membrane integrity were studied by measuring cell volume changes and release of 51Cr. There was a significant release of 51Cr after 1 hr exposure to submillimolar concentrations of patulin. Similarly, there was a significant decrease in ATP in cell cultures exposed to 0.5 mM patulin for 15 min and in cultures exposed to 0.05 mM patulin for 2 hr. There was a significant increase in mean cell volume after 2 hr exposure to 1.0 mM patulin but not after a 1 hr exposure. The effects of patulin on protein and RNA synthesis were studied by monitoring the incorporation of [3H]leucine and [3H]uridine, respectively. Inhibitions of protein and of RNA synthesis were both dose and time dependent. Protein synthesis was the most sensitive cellular parameter studied, with 50% inhibition after 1 hr at ca. 0.002 mM patulin. The data demonstrate that patulin is cytotoxic for rat alveolar macrophages in vitro.

Adenosine Triphosphate↗
PubMed1985

Neurotensin immunoreactivity in post-mortem brain is increased in Down's syndrome but not in Alzheimer-type dementia.

Neurotensin immunoreactivity and choline acetyltransferase (ChAT) activity were measured in post-mortem brain from 10 cases of Down's syndrome (7 aged 53-63 years, one aged 27 years, one aged 16 months and one aged 10 months), 6 cases of Alzheimer-type dementia (ATD) and 19 control subjects (13 aged 40-88 years and 6 aged 9-18 months). Neurotensin concentrations in anterior and basal hypothalamus, amygdala, septal area, caudate nucleus and temporal cortex were unaltered in ATD. The concentrations of neurotensin were significantly increased in the caudate nucleus, temporal cortex and frontal cortex in the cases of Down's syndrome aged 53-63 years with the neuropathological features of ATD, and were also increased in the cerebral cortex of the 27-year-old, which did not have the neuropathological features of ATD, and in two infant Down's cases. ChAT activity was reduced in the ATD and the 53-63-year-old cases of Down's syndrome, but not in the 27-year or 10-month-old Down's cases. The increased neurotensin concentrations appear to be a feature of Down's syndrome not related to the presence of plaques and neurofibrillary tangles or to a deficit in ChAT activity.

Adult↗
PubMed1985

Skin test, RAST and clinical reactions to peanut allergens in children.

One-hundred-and-four children were skin-tested with four peanut-allergen preparations, a commercial extract, extracts of raw and roast peanuts prepared by NH4HCO3 extraction, and a wheatgerm lectin-reactive glycoprotein obtained by affinity chromatography. The presence of symptoms after ingestion of peanut or peanut products was also recorded. The roast allergen extract provided the greatest specificity with eight symptomatic children having a positive skin test and only one positive skin-test reaction in an asymptomatic child in the group of 104 children tested. Despite differences in the incidence of skin-test reactions there was a strong correlation between raw, roast and commercial RAST suggesting common allergens were being identified by circulating IgE. Clinical sensitivity was observed particularly in younger children with 75% of the children being under 4 years of age. A positive roast skin test or a RAST test adds confirmation to the clinical history of allergic reactions to peanuts.

Adolescent↗
PubMed1985

Choline acetyltransferase activity in the pars distalis, preoptic area and striatum during the rat estrous cycle.

Choline acetyltransferase (CAT) activity of the striatum, preoptic area (POA), and pars distalis (PD) of the anterior pituitary gland was measured on each day of the 4-day estrous cycle of adult Wistar rats. Only in the PD did CAT activity vary significantly during the cycle, with the activity being lower during estrus than at other stages of the cycle. The CAT activity of the PD was extremely low, approximately 500 nmol/h/g protein, and, therefore, the specificity of the CAT activity of the PD was verified in studies on substrate requirement, the effect of a CAT inhibitor, and by paper chromatography of the reaction products. Measurement of CAT activity in saline-perfused glands, in sections of tissue taken from the lateral extremes of the PD and in hypophysial portal blood showed that the CAT activity of the PD was intrinsic, and not due to CAT activity in entrapped blood or adjacent tissues. The precise cellular origins of CAT in PD and the significance of the cyclical variation require further investigation.

Animals↗
PubMed1984

Percutaneous angioplasty of stenoses of bypass grafts or of bypass graft anastomotic sites.

Forty patients who had stenoses of coronary artery bypass grafts or stenoses of the proximal or distal coronary insertion sites were treated with percutaneous transluminal angioplasty (PTA). PTA was successful in 78% of the patients. Mean stenoses were diminished from 86% to 34% in luminal diameter. One patient needed emergency coronary artery bypass grafting. There were no deaths associated with PTA. Follow-up angiography showed continued patency in asymptomatic patients, whereas in all but 1 patient with recurrent symptoms restenosis had developed at the PTA site. In 38% of patients restenosis developed after successful PTA; the highest restenosis rate was after PTA of aorta/graft anastomoses or proximal graft stenoses. In conclusion, PTA is a successful, low risk alternative to repeat coronary artery bypass grafting, although the restenosis rates at some PTA sites are high.

Adult↗
PubMed1984

Aflatoxin in respirable airborne peanut dust.

Laboratory shelling and pilot handling operations were conducted to determine if peanut dust generated by such operations contained significant amounts of aflatoxin. Air samples were collected from points of highest dust concentration. No aflatoxin B1 was detected in dust from uncontaminated lots. Aflatoxin B1 levels of 700 ppb and 7.6 ng/m3 were detected from highly contaminated lots. The contamination of the dust was directly proportional to the contamination of the lots handled or shelled. In the shelling tests, the level of contamination of the dust samples was about one-ninth of the level of contamination of the peanuts. In the handling tests, the level of contamination of the dust samples was about half the contamination level of the peanuts. These results indicate that most of the contaminated dust was probably removed by handling operations prior to shelling. Although workers are not routinely exposed to such levels of contaminated dust, these findings suggest the need for a more thorough study of peanut dust during handling or processing of contaminated peanuts.

Aflatoxin B1↗
PubMed1984

Species differences in the effect of decreased CSF sodium concentration on salt appetite.

During the course of evolution from the beginning of the Caenozoic period, the mammalian species have irradiated into increasingly diverse environments and these physical conditions have imposed powerful selection pressures on the systems of water and salt homeostasis. In the case of physiological actions of hormonal elements of the control systems, effects of antidiuretic hormone and aldosterone on water and salt conservation and of renin-angiotensin II on blood pressure and aldosterone secretion show a general similarity across mammalian species. However, evidence is accruing that there may be large species variation in the vectors of physical, chemical and hormonal changes of the milieu which cause water and salt intake. In the sheep, physiological degree of reduction of CSF [Na] produced by IVT infusion of various hypertonic or isotonic saccharide solutions has a powerful stimulating effect on salt appetite of both Na replete and Na deficient animals. Increasing CSF [Na] reduces appetite. The 0.7 M mannitol CSF infusions initially stimulated thirst but eventually depressed it, presumably due to reduction of CSF [Na]. By contrast, in wild rabbits infusion of 0.9 M mannitol CSF for 2 days at 17 microliter/h caused a large reduction of water intake, a diuresis and no significant increase in salt intake. In laboratory white rats, 0.7 M mannitol CSF infusion at 10 microliter/h for 4 days by Alzet pump, did not increase salt appetite though the infusion was calculated to produce moderate reduction of CSF [Na]. It would appear that there may be significant species differences in effect of reduced CSF [Na] on salt appetite.

Animals↗
PubMed1983

Catecholamines and cholinergic enzymes in pre-senile and senile Alzheimer-type dementia and Down's syndrome.

Noradrenaline, dopamine, homovanillic acid (HVA), choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) levels were measured in post-mortem brains from 8 cases of pre-senile Alzheimer-type dementia (ATD), 5 cases of senile ATD, 4 cases of Down's syndrome aged 53-57 years, one 27-year-old case of Down's syndrome and 13 controls. In the controls, the concentration of noradrenaline in hypothalamus (P less than 0.05) and mamillary body (P less than 0.02) decreased with age. Compared with age-matched controls, noradrenaline levels in these areas were more markedly reduced in pre-senile ATD (P less than 0.01), the 53-57-year-old cases of Down's syndrome (P less than 0.001) and in the 27-year-old Down's, than in senile ATD (hypothalamus P less than 0.05, mamillary body, n.s.). Dopamine and HVA concentrations in caudate nucleus were unaltered in pre-senile or senile ATD but dopamine was decreased (P less than 0.01) in the older cases, although not in the 27-year-old case, of Down's syndrome. In the olfactory tubercle in ATD the level of HVA was unaltered but the activity of ChAT was decreased (P less than 0.01). ChAT activity was reduced in pre-senile ATD (P less than 0.001), the older Down's cases (P less than 0.01) but not the young Down's case, and senile ATD (P less than 0.001) in the temporal cortex and in pre-senile ATD (P less than 0.001) and the older Down's cases (P less than 0.001) but not senile ATD in the caudate nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholinesterase↗
PubMed1983

Phosphate-activated glutaminase in relation to Huntington's disease and agonal state.

Involvement of phosphate-activated glutaminase in Huntington's disease and agonal state was investigated in caudate nucleus and frontal cortex from postmortem brains. In Huntington's disease the activities of phosphate-activated glutaminase, glutamic acid decarboxylase, succinic dehydrogenase, choline acetyltransferase, and acetylcholinesterase were significantly reduced in the caudate nucleus, but not in the frontal cortex. The activity of phosphate-activated glutaminase, and to a lesser extent of glutamic acid decarboxylase, was reduced in cases of terminal illness, as compared with cases of sudden death. Succinic dehydrogenase and choline acetyltransferase were reduced only in the few cases of prolonged and severe terminal illness. Enzyme activities of the caudate nucleus were more affected by agonal state than were those of frontal cortex. Results indicate that phosphate-activated glutaminase could be a useful marker of neuronal damage due to agonal state, and that phosphate-activated glutaminase and succinic dehydrogenase are reduced in Huntington's disease.

Acetylcholinesterase↗
PubMed1983

Percutaneous transluminal coronary angioplasty: report of complications from the National Heart, Lung, and Blood Institute PTCA Registry.

The complications reported in the first 1500 patients enrolled in the National Heart, Lung, and Blood Institute Percutaneous Transluminal Coronary Angioplasty (PTCA) Registry are analyzed. Data were contributed from 73 centers between September 1977 and April 1981. PTCA was successful in 63% of attempts. Five hundred forty-three in-hospital complications occurred in 314 patients (21%). The most frequent complications were prolonged angina in 121, myocardial infarction (MI) in 72, and coronary occlusion in 70. One hundred thirty-eight patients (9.2%) had major complications (MI, emergency surgery or in-hospital death). One hundred two patients (6.8%) required emergency surgery, usually for coronary dissection or coronary occlusion. Sixteen patients (1.1%) died in-hospital; the mortality rate was 0.85% in patients with one-vessel disease and 1.9% in those with multivessel disease. The mortality rate was significantly higher in patients who had had bypass surgery (p less than 0.001). Nonfatal complications were significantly influenced by the presence of unstable angina (p less than 0.001) and initial lesion severity greater than 90% diameter stenosis (p less than 0.001). This report delineates and assesses the complications encountered with PTCA during its initial 3 1/2-year clinical experience. These results support the relative safety of PTCA as a method of nonsurgical myocardial revascularization in carefully selected patients.

Adult↗
PubMed1983

Neonatal deaths in bonnet monkeys born to dams with rudimentary papillae mammae.

Deaths due to dehydration and starvation occurred in the early neonatal period in bonnet monkey (Macaca radiata) infants housed with their dams in an outdoor half-acre corral. Dams were found to have small, rudimentary papillae mammae of insufficient size to permit suckling. Both papillary and breast tissue of affected dams were histologically normal; the nipples differed macroscopically from those of normal females only in size. This abnormality accounted for half of the neonatal mortality experienced in this breeding colony over a 5-year period.

Animals↗