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Biomedical subjects

A D Macrae

Publications and source records attributed to A D Macrae.

At least 19 recordsLinked to original sources
PubMed1992

Very high concentrations of islet amyloid polypeptide are necessary to alter the insulin response to intravenous glucose in man.

Islet amyloid polypeptide (IAPP) is a beta-cell peptide that can oppose insulin action in animal systems, but has not been shown to have any action in man; previously, we failed to show an effect of infused IAPP on iv glucose tolerance in human volunteers. We have reexamined its effects at even higher concentrations in six volunteers who received iv glucose (0.5 g/kg) during infusions of IAPP (25 and 50 pmol/kg.min) or normal saline. IAPP rose from a mean basal of 14.7 +/- 5.3 pmol/L to peak levels of 1,420 +/- 110, 2,240 +/- 140, and 27.7 +/- 9 pmol/L, respectively. IAPP at 25 pmol/kg.min had no effect on the plasma glucose disposal rate or the total incremental insulin response, but, in contrast, at 50 pmol/kg.min decreased the insulin response to glucose compared to the saline infusion (incremental area under the curve, 11,276 +/- 2,353 vs. 17,549 +/- 2,687 U; mean +/- SEM; P less than 0.02). This decrease was observed both during the first phase (0-10 min postglucose) insulin response (3,210 +/- 985 vs. 4,382 +/- 815 U; P less than 0.05) and the second phase response (11-90 min, 8,520 +/- 1,719 vs. 13,679 +/- 2,326 U; P less than 0.03). Glucose disposal rate, however, was unaffected (2.0 +/- 0.2 vs. 1.9 +/- 0.2). Thus, circulating IAPP concentrations greater than 90 times normal postprandial peaks were necessary to affect the insulin response to glucose. IAPP appears unlikely to be a circulating hormone influencing carbohydrate metabolism in man.

Adult↗
PubMed1990

Diaphragmatic weakness in hereditary motor and sensory neuropathy.

Six patients severely affected by hereditary motor and sensory neuropathy (HMSN), four type I and two type II, had clinical evidence of diaphragmatic weakness. One presented with cardiorespiratory failure secondary to nocturnal hypoventilation, and three others were unable to lie flat because of dyspnoea. Diaphragmatic paralysis should be considered as a cause of respiratory or cardiac failure in cases of HMSN.

Adult↗
PubMed1989

Assessment of postural hypotension in elderly patients.

Change in blood pressure on standing was measured in 23 geriatric inpatients during the morning. The fall in systolic blood pressure was found to be greatest 30 s after standing, at 9.3 +/- 3.3 (SEM) mmHg and had returned to the supine levels within 2 min. In contrast, the diastolic pressure rose to a maximum of 9.7 +/- 1.8 mmHg by 2 min. In 13 patients the measurements were repeated in the afternoon after lunch. The systolic blood pressure drop was significantly greater: 20.8 +/- 3.6 against 7.1 +/- 2.0 mmHg in the morning (p = 0.01). Standardization of the time after standing and time of day of measurement may allow more precise comparisons of different studies.

Aged↗
PubMed1986

The rise and fall of Legionnaires' disease in Nottingham.

The annual number of confirmed cases of Legionnaires' disease in both Nottingham, and England and Wales, reached a peak in 1980 and has since declined. Legionella infection is a rare cause of community-acquired pneumonia managed at home (accounting for less than 1% of cases), more common in those admitted to hospital (5-15%) and more common still in patients with severe pneumonia as seen on an intensive care unit (up to 30% of cases). Antibiotic therapy for any patient with moderate or severe pneumonia of uncertain aetiology should cover legionella infection.

England↗
PubMed1985

Aetiology and outcome of severe community-acquired pneumonia.

Between January 1972 and December 1981, 50 patients with severe community-acquired pneumonia were admitted to the intensive care unit of a district general hospital. A causal pathogen was identified in 41 cases (82%). Streptococcus pneumoniae (16 cases), Legionella pneumophila (15 cases) and Staphylococcus aureus (5 cases) were the commonest. Assisted ventilation was required in 44 patients, of whom 25 died (57%). All 5 patients with staphylococcal pneumonia and 12(75%) with pneumococcal pneumonia died. Only 5 (33%) with Legionnaires' disease died. Mortality was significantly associated with age. Recommendations for the management of severe pneumonia are made.

Adult↗
PubMed1985

Differential blocking actions of idazoxan against the inhibitory effects of 6-fluoronoradrenaline and clonidine in the rat vas deferens.

The prejunctional inhibitory effects of clonidine and 6-fluoronoradrenaline (6-FNA) have been evaluated in the isolated prostatic segment of the rat vas deferens, against the twitch response evoked by low frequency (0.1 Hz) field stimulation. The inhibitory potency of 6FNA was significantly increased in the presence of cocaine (1 microM) or pargyline (10 microM), but was not modified in the vas deferens from rats pretreated with reserpine when the endogenous levels of noradrenaline (NA) were decreased by 97%. Clonidine was significantly more potent than 6-FNA as an inhibitory agonist, and the potency of clonidine was not modified after cocaine, pargyline or reserpine. The alpha 2-adrenoceptor blocking agent idazoxan, was a competitive antagonist against the inhibitory effects of clonidine under all experimental conditions. In contrast, the only antagonism shown by idazoxan against the inhibitory effects of 6-FNA was in the presence of cocaine (1 microM), and this antagonist effect of idazoxan was not concentration-related. Low concentrations of 6-FNA caused concentration-dependent facilitatory effects on the twitch response, which were significantly greater after treatment with idazoxan (1 microM) in reserpine-treated vas deferens. These facilitatory effects of 6-FNA were always observed in the presence of prazosin (300 nM) and also after treatment of the preparations with phenoxybenzamine (10 microM), a concentration which abolished the inhibitory actions of both clonidine and 6-FNA. The facilitatory effects on the twitch response induced by low concentrations of 6-FNA are therefore unlikely to be due to either alpha 1- or alpha 2-adrenoceptor stimulation. In conclusion, the failure of idazoxan to block the inhibitory effects of 6-FNA, while exerting a potent competitive antagonism of clonidine-induced inhibitory effects, supports the proposal that alpha 2-adrenoceptors may in fact be subdivided into two subclasses, involving imidazoline and phenylethylamine recognition sites.

Adrenergic alpha-Antagonists↗
PubMed1983

Psittacosis.

Explore the source record for details and available documents.

Adult↗
PubMed1982

Hospital study of adult community-acquired pneumonia.

The cause of primary pneumonia was diagnosed in 124 of 127 consecutive adult patients admitted to hospital with community-acquired illness. Pneumococcal infection was found in 96 (76%) patients and legionnaries' disease was the second commonest infection identified (15%). Other bacterial infections were uncommon. 11 patients had atypical pneumonia, including 7 with psittacosis. There were several mixed infections and most of the 11 patients with viral infections also had bacterial pneumonia. 19 patients died (15%) and mortality was associated with increasing age, the presence of coexisting disease, and the cause of the pneumonia. Recognition of the most likely causes of severe pneumonia allows logical initial antibiotic treatment for such patients admitted to hospital.

Adolescent↗
PubMed1982

Laboratory diagnosis of smallpox: role of the Virus Reference Laboratory, Colindale, 1947-70.

The Virus Reference Laboratory, Colindale, first embarked on laboratory investigations for smallpox early in 1947. From then, in conjunction with the Department of Bacteriology, University of Liverpool, it provided a complete diagnostic service throughout England and Wales until 1962, after which the service became available regionally until eradication was effected. Up to 1970 it had investigated 2696 specimens from suspected cases of smallpox and had recovered 108 strains of variola and 248 of vaccinia virus. These last were from persons suffering the complications of vaccination. Some outbreaks following smallpox importation are discussed but infection among laboratory staff during this period was not demonstrated.

England↗
PubMed1980

Electron microscopic evidence of flagella and pili on Legionella pneumophila.

Twenty-one strains of Legionella pneumophila, representing the six known serotypes of the organism, cultured on various bacteriological media and in the yolk sacs of fertile hens' eggs were examined by negative stain electron microscopy for flagella and pili. These appendages were usually observed after cultivation on media capable of inducing an early profuse growth of the organisms.

Culture Media↗
PubMed1979

The antibody response in Legionnaires' disease.

From 22 patients with Legionnaires' disease, 86 sera were examined for specific serotype 1 IgM and IgG antibodies by the indirect immunofluorescence technique. No antibody was detectable until 8 days or more from the onset of symptoms. When produced the amount was widely variable and remained detectable for periods from less than 34 days to more than 1 year. Intially IgM antibody predominated, ten patients produced only IgM in the first 21 days, six produced only IgM in the first 28 days and three did not produce IgG at any time. One patient, and possibly a second, produced only IgG antibody. Since IgM antibody was still present in one patient after a year it is important not to accept the presence of this as evidence of very recent infection. It is advisable that any type of serological test for L. pneumophila infection should detect the production of both IgM and IgG antibodies.

Antibodies, Bacterial↗
PubMed1979

Legionnaires' disease in Nottingham, England.

Legionnaires' disease bacterium was identified as the cause of severe pneumonia in some Nottingham, England, patients in 1977. Laboratory studies were not restricted to Nottingham but included several other areas in England. The 41 cases identified were evenly divided between areas; they also accounted for about one half of all cases for the entire country. No source of infection has been identified in these sporadic cases. There was no contact between patients, and only a few had travelled abroad before their illnesses. Serologic sampling of populations in Nottingham did not reveal a large background of infection. Only 31 of 2023 sera tested had low titer antibody to the Pontiac antigen used. Guinea-pig antisera to two positive lung extracts showed an antigenic relation to the Pontiac but not to the Togus strain,suggesting strain variation.

Antibodies, Bacterial↗