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Biomedical subjects

M Nelson

Publications and source records attributed to M Nelson.

At least 379 records · Page 21Linked to original sources
PubMed1987

Ritanserin and serotonergic mechanisms in blood pressure and fluid regulation in sheep.

1. In previous studies, exogenous serotonin (5-HT), administered intravenously, caused dose-related increases in mean arterial pressure and heart rate in conscious sheep. The 5-HT2 antagonist ketanserin (0.1 mg/kg per h, i.v.) was shown to lower blood pressure in the conscious sheep primarily through antagonism of alpha-adrenoceptors. 2. A newer 5-HT2 antagonist, ritanserin, is a more selective antagonist in vivo, as it attenuated or abolished pressor responses to exogenous 5-HT, but not to phenylephrine. 3. When infused alone, ritanserin (0.1 mg/kg per h, i.v.) failed to produce a decrease in blood pressure, suggesting that 5-HT antagonistic properties are not sufficient by themselves to lower blood pressure. 4. Ritanserin displayed a different metabolic profile to ketanserin, with a markedly decreased water intake. The mechanism of this effect is unresolved, but may imply a permissive role for 5-HT in the modulation of drinking responses in the sheep. 5. Ritanserin did not modify ACTH-induced hypertension in sheep.

Animals↗
PubMed1987

Diet, infection, and acute appendicitis in Britain and Ireland.

During 1979-82 hospital discharge rates after emergency admission for acute appendicitis were higher in Eire (17.4 per 10,000 population) than in England (10.3), Scotland (11.1), or Wales (12.3). Comparison of food consumption between the four countries, and between the health board areas of Eire and regions of Scotland, shows that appendicitis rates are highest in communities that consume more potatoes, sugar, and cereals, and less non-potato vegetables and fruit. The rates are also related to mortality from enteric and respiratory infections, to general practice consultations for infective disease, and to postneonatal mortality. This is evidence in favour of the hygiene hypothesis for the aetiology of appendicitis.

Acute Disease↗
PubMed1987

Enhancement of the apparent cleavage specificities of restriction endonucleases: applications to megabase mapping of chromosomes.

We have described how DNA methylases may be used to enhance the apparent specificities of restriction endonucleases [9-11, 17, 18] to generate DNA fragments averaging 6000 to 270,000,000 base pairs on random DNA. Taking into account the non-random arrangement of natural DNA, we have predicted the rarity of certain recognition sequences in the genomes of several species.

Base Sequence↗
PubMed1987

Thyroid gland size in pregnancy. An ultrasound and clinical study.

We estimated the size of the thyroid gland by palpation and measured thyroid gland volume with ultrasound in the immediate postpartum period and six months after delivery in 16 women. The 13% reduction in the mean thyroid gland volume detected six months after delivery implied that the thyroid gland enlarges slightly during pregnancy. Physical examination, however, did not detect any goiters during the immediate postpartum period and did not identify a change in thyroid gland size six months after delivery. The thyroid gland enlargement that occurs during pregnancy is not large enough to be detected by physical examination. We urge physicians to discard the commonly held notion that goiter frequently develops during pregnancy.

Female↗
PubMed1987

Iodine intake and excretion in two British towns: aspects of questionnaire validation.

One hundred and eighty-nine women aged 25-64 years living in Preston and Southampton completed a postal questionnaire on their usual consumption of the major dietary sources of iodine. A subsample of 56 women collected 24-h urine specimens. Median iodine intakes based on the questionnaire responses and food consumption tables were 99 micrograms and 97 micrograms per day, respectively, but these figures rose to 105 micrograms and 118 micrograms when the women were given the opportunity to revise their original responses and analysed values for milk iodine were used. Median urinary iodine excretion (determined by the dry-ashing method) was 70 micrograms/day in Preston and 76 micrograms/day in Southampton. Although positive associations between intake and excretion were observed, the study lacked sufficient statistical power to validate the questionnaire as a measure of iodine intake. Some problems of questionnaire validation are discussed.

Adult↗
PubMed1987

[Aneurysm of the ampulla of Galen. Nosologic reflections and endovascular therapy].

Nosologic concepts distinguish three types of aneurysm of Galen's ampulla: true aneurysms, related aneurysms, false aneurysms, whatever the type the majority of these malformations can be treated by the endovascular approach, frequently the most effective alternative therapy. Experience acquired during treatment of intracerebral arteriovenous angioma allows perfect control of direct, high output arteriovenous fistula by injection of pure isobutyl cyanoacrylate. Occlusion of shunts should be combined with prevention of consequences, that is to say extensive venous thrombosis. Two cases are reported that demonstrate the value of post-embolization heparin therapy.

Adult↗
PubMed1986

Vegetable consumption and acute appendicitis in 59 areas in England and Wales.

Rates of acute appendicitis in 59 areas of England and Wales were correlated with consumption of different foods per caput, measured from household food purchases. There was a statistically significant positive correlation with potato consumption and a negative correlation with non-potato vegetables. This negative correlation depended mainly on green vegetables and tomatoes. There was no consistently significant correlation with any other main food group. In particular the correlations with cereal foods, cereal fibre, and total dietary fibre were small and not significant. Green vegetables and tomatoes may protect against appendicitis, possibly through an effect on the bacterial flora of the appendix.

Acute Disease↗
PubMed1986

Optic nerve hypoplasia and maternal diabetes mellitus.

Altitudinal visual field defects were discovered in four young women on routine eye or general physical examinations. This led to extensive investigations because three of them were falsely presumed to have acquired disorders of the central nervous system. In each case the defect appeared to result from congenital hypoplasia of the optic nerve associated with maternal diabetes mellitus. Congenital optic nerve hypoplasia should be included in the differential diagnosis of visual field defects even when they are discovered in adults. Hypoplasia consequent to maternal diabetes mellitus is apt to be associated with excellent visual acuity and is usually an isolated defect. The female offspring of diabetic mothers may be at greater risk than the male offspring for the development of this anomaly.

Adolescent↗
PubMed1986

The distribution of nutrient intake within families.

1. During 1978 and 1979, the 343 members of seventy-nine families representative of households with two adults and two or three children living in Cambridge, England, completed 7-d records of food consumption using the semi-weighed technique. Nutrient intakes were calculated using food composition tables. 2. Amongst males, the average intakes of energy and most nutrients were highest in men and boys aged 11-17 years, and lowest in boys under 5 years. Amongst females, intakes were highest in girls aged 11-17 years, and lowest in those under 5 years. At each age, intakes in males were generally higher than those in females. 3. Nutrient distribution within families was described using the ratio, intake of each subject:intake of the male head of the household. The problems inherent in using this ratio are discussed. 4. The distribution of nutrient intakes within the families was not in accordance with the recommended daily amounts (RDA). Men and young boys received more than their fair share of the family diet, while women and girls aged 5-17 years received less. 5. Estimates of dietary adequacy based on the averages of family consumption and requirements (RDA) concealed up to twofold variations in the adequacy of diet of different age-sex-groups. 6. The interpretation of dietary adequacy in household food surveys should take into account the distribution of nutrient intakes within the household, as the distribution may be substantially different from that predicted by the RDA.

Adolescent↗
PubMed1986

A case-control study of acute appendicitis and diet in children.

The diets of 53 Southampton children who had had appendicitis were compared with those of two sets of age-sex matched controls using a seven-day weighed food record. One set of controls comprised classmates of the cases; the other was a random sample of all schoolchildren in the city. The cases weighed less and were shorter in height; they had lower intakes of energy, all the main nutrients and water. The differences in weight and water intake were statistically significant. Low water intake was identified as a risk factor independent of other factors. Consumption of dietary fibre from cereals and vegetables in relation to total energy intake and body weight was similar in cases and controls.

Acute Disease↗
PubMed1986

A prospective comparison of iotrolan, iohexol and iopamidol for lumbar myelography.

The provisional results are presented of a comparative blind trial of iotrolan, iohexol and iopamidol for lumbar myelography. The aim of the trial was to assess the relative safety, tolerance and radiologic efficacy of the media. From the data available to date the incidence of side effects is similar for all three substances. Iotrolan does not provide specific imaging advantages.

Contrast Media↗
PubMed1985

Purification of Mbo II methylase (GAAGmA) from Moraxella bovis: site specific cleavage of DNA at nine and ten base pair sequences.

The restriction modification methylase M. Mbo II has been purified using a sensitive oligonucleotide linker assay. The enzyme methylates the Mbo II recognition sequence* GAAGA at adenine to produce GAAGmA. M. Mbo II can be used in conjunction with the methylation dependent restriction endonuclease Dpn I (GmATC) to produce cleavage at the 10 base sequence GAAGATCTTC. When M. Mbo II is used in combination with M. Cla I (ATCGATCGAT), cleavage by Dpn I occurs at the four ten base sequences GAAGATCTTC, GAAGATCGAT, ATCGATCTTC and ATCGATCGAT, which is equivalent to a nine base recognition site. The use of combinations of adenine methylases and Dpn I to generate highly selective DNA cleavages at a variety of sequences up to fourteen base pairs is discussed.

Base Sequence↗
PubMed1985

Human cytomegalovirus polypeptides stimulate neutralizing antibody in vivo.

At least three human cytomegalovirus polypeptides are targets for virus neutralizing antibody; a single protein of 86,000 molecular weight (p86) and two coimmunoprecipitating proteins of 130,000 and 55,000 molecular weight (p130/55). These polypeptides have been isolated by immunoaffinity chromatography and tested for immunogenicity in guinea pigs. Neutralizing antibody was detected after immunization with both p86 and p130/55. Hyperimmune sera to p130/55, but not p86, were dependent upon guinea pig complement for virus neutralization.

Animals↗
PubMed1985

Family food purchases and home food consumption: comparison of nutrient contents.

Estimates of nutrient intakes based on food purchasing records modelled on the National Food Survey (NFS) were compared with nutrient intakes calculated from food consumption records based on a semi-weighted method, a combination of weighing and household measurement techniques. Of eighty-two families in Cambridge who completed the study, thirty-two were volunteers and fifty were from a random sample in which the co-operation rate was 73%. The estimated energy and nutrient contents of the Cambridge food purchases were very similar to those reported by the NFS for families of similar composition and income. The energy intakes obtained by the semi-weighed method were compared with results from twenty-five studies of energy intake based on quantitative measurements of food consumption: there was no evidence to suggest that the semi-weighed method consistently under- or overestimated intakes in the Cambridge subjects. Purchases adjusted to allow for waste and consumption of food by visitors contained significantly more energy, protein, carbohydrate, calcium, iron and dietary fibre than measured home food consumption. There was no significant difference in the nutrient content of purchases and consumption per 4.184 MJ (1000 kcal), with the exception of Fe and ascorbic acid. Measured wastage of edible food in thirty-one families averaged 3.2% of purchases. Estimate of wastage in all eighty-two families was 3.8%, and consumption of food by visitors accounted for 3.0% of purchases. The excess of purchases over measured home food energy intake is probably accounted for by a net increase in larder stocks rather than wastage, consumption of food by visitors, or under-recording of intakes.

Adolescent↗
PubMed1985

Nutritional goals from COMA and NACNE: how can they be achieved?

A simple way of altering the average British diet to make it comply with the short-term NACNE nutritional goals was discovered by comparing the diet of a cross-section of Cambridge adults with that of a subgroup whose diet approached the desired objectives. Between 1977 and 1979, 105 men and 112 women aged 18-57 completed 7-day semi-weighed records of food consumption. Although no subject achieved all of the NACNE or COMA goals, seven men and three women had diets in which fat provided less than 35 per cent of energy, alcohol less than 10 percent, with fibre more than 20 g/day; total sugars provided 25 per cent of energy. When these diets were compared with those of the rest of the sample (excluding diets where alcohol provided more than 10 per cent of energy), it was seen that men and women in the low-fat, high-fibre group ate more white bread, high-fibre breakfast cereals, low-fat meat dishes, and vegetables, and less brown bread, biscuits, eggs, poultry and fried fish. Only small changes were needed to make the average Cambridge diet consistent with the short-term NACNE goals for fat and fibre. Achieving the COMA or long-term NACNE goals will require more radical change, based on strategies to provide the necessary foodstuffs and nutrition education to allow informed individual choice.

Adolescent↗