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Biomedical subjects

D M Jones

Publications and source records attributed to D M Jones.

321 records · Page 18Linked to original sources

Mycoplasma hominis in pregnancy.

One hundred and seventyone antenatal patients were examined for the presence of ;large colony' mycoplasmas in the vagina, and for complement-fixing antibody to Mycoplasma hominis. In 25 patients the findings before and after delivery were compared. In patients from whom M. hominis was grown, antibody was twice as common after delivery, and the development of antibody was sometimes associated with pyrexia and signs of genital tract infection.

Adolescent↗

Prevalence of antibody to Helicobacter pylori in children in northern Nigeria.

Helicobacter pylori infection is common in northern Nigeria, but the age of acquisition is unknown. In a prospective study, immunoglobulin G antibodies to H. pylori were measured in 143 children under the age of 20 years. Ninety-one percent of 43 randomly chosen subjects over 10 years had antibodies to H. pylori. A further 100 children under 10 years presenting to the University of Maiduguri Teaching Hospital were also tested. Sixty-nine percent had antibodies, including 58% of those aged under 1 year. H. pylori infection is acquired at an early age, and in this study was not associated with any other pathology. This study was carried out in an area where peptic ulceration and gastric cancer are uncommon. The early acquisition of H. pylori infection may be important in relation to its apparent lack of pathogenicity.

Adolescent↗

Conducted current on guidewires in single lumen papillotomes.

An in vitro electrical circuit was designed to measure conducted current in plastic-coated guidewires and standard guidewires inserted in a single lumen papillotome. Single lumen papillotomes, which are more flexible than double lumen papillotomes, require the removal of the guidewire before electrosurgery due to concern over conducted current. In an in vitro electrical circuit, equivalent current was measured in both the papillotome wire and the standard guidewire. Plastic-coated guidewires did not allow any current flow. The advantages of flexible single lumen papillotomes and maintenance of deep biliary cannulation over a guidewire may be combined if insulated plastic-coated guidewires are used.

Ampulla of Vater↗

The impact of broadband noise on serial memory: changes in band-pass frequency increase disruption.

Irrelevant sound consisting of bursts of broadband noise, in which centre frequency changes with each burst, markedly impaired short-term memory for order. In contrast, a sequence of irrelevant sound in which the same band-pass noise burst was repeated did not produce significant disruption. Serial recall for both visual-verbal (Experiment 1) and visual-spatial items (Experiment 2) was sensitive to the increased disruption produced by changing irrelevant noise. The results provide evidence that sounds that are largely aperiodic can produce marked disruption of serial recall in a similar manner to periodic sounds (e.g., speech, musical streams, and tones), and thus show a changing-state effect.

Female↗

Participation of the renin-angiotensin system in regulating the excretory response to acute sodium ingestion.

1. A gastric sodium monitor has been proposed, based upon greater urinary sodium excretion after gastric, compared with intravenous, sodium loading. However, this difference has only been demonstrated in animals and humans on a low sodium diet prior to study. This suggests involvement of a system activated by decreased sodium intake. As the renin-angiotensin system is the most active of these, this study sought to determine whether angiotensin II (AII) might act as a humoral mediator for this gastric sodium monitor. 2. Male New Zealand white rabbits with a gastrostomy tube in situ were placed on a low sodium diet (0.008% NaCl) for 7 days. To determine if differences in plasma AII might explain the different natriuretic responses AII was measured 0,5,10, 30, 60 and 120 min after a 1.5 mmol/kg sodium load given gastrically or intravenously. To determine whether the AII response was specific to low salt diets the gastric salt load was given after equilibration on normal (2.2% NaCl) and high (4.4% NaCl) sodium diets. 3. In rabbits on the low sodium diet plasma AII decreased significantly at 5 min after both gastric (P < 0.025) and intravenous (P < 0.05) sodium and returned to baseline by 10 min in the latter. In contrast after gastric sodium AII remained less than in controls throughout (120 min, P < 0.05). In the rabbits on the normal and high sodium diets plasma AII concentration increased non-significantly after gastric sodium administration. 4. We conclude that circulating AII may participate as a mediator of the gastric sodium monitor.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

Radiographic abnormalities of the lumbar spine in college football players. A comparative analysis.

The purpose of this study was to make a direct comparison between lumbar spine radiographs of incoming college football players and of an age-matched control group to determine whether there is a higher prevalence of lumbar spine abnormalities in football players before competing at the Division I level. We reviewed 187 lumbar spine radiographs. Of these, 104 were taken as a standard part of the preparation physical examination for incoming college football players. The remaining 83 radiographs were taken during routine preemployment physicals at a local factory. Each radiograph was read independently by three separate orthopaedic radiologists in a blinded fashion. Data were collected and statistically evaluated for 13 variables. The rate of spondylolysis was only 4.8% in our group of athletes and 6.0% in the control group (not significantly different). Only in the category of degenerative changes was a significant difference found. The control group had a 16.9% incidence of disk space narrowing and spurring and the football players had a 6.7% incidence. The remainder of the variables were not significantly different between the two groups. Our findings differ from previously published reports and indicate that football players entering college at the Division I level may have a similar prevalence of radiographic lumbar spine abnormalities, including spondylolysis and spondylolisthesis, as age-matched controls.

Adult↗

Indispensable benefits and unavoidable costs of unattended sound for cognitive functioning.

Critical to survival, and also to the organism's efficient management of the flow of information in the brain, is attentional selectivity; the ability to select one source of information to guide action whilst ignoring others that are irrelevant to the current behavioural goal. But such selectivity is not merely the inclusion of the relevant information and the complete neglect of irrelevant information. We discuss in this paper the way that all sound is processed in an obligatory fashion--whether relevant or irrelevant--and discuss the fate of sound in the case when it is irrelevant to the immediate mental task. Using the so-called irrelevant sound paradigm we show that unattended information is both registered and organised. This obligatory process of organisation compromises the efficiency of particular types of mental activity. We discuss how such interference comes about but the key emphasis is upon the possible beneficial effects of such processing-of-the-irrelevant, in allowing the switching of attention to be more facile and intelligent and in allowing the accumulation of evidence about statistical regularities in the auditory world (such as those helpful to the efficient perception, acquisition and use of language). In sum, we describe how purposeful processing based on directed attention is in a state of tension with the obligatory, automatic processing of the unattended. One of the consequences of this tension is typically manifested in auditory distraction, but the benefits of processing of the attended may considerably outweigh this disadvantage.

Attention↗

H-77: a potent new renin inhibitor. In vitro and in vivo studies.

Chemical modification of the backbone at the cleavage site in the (6-13)-octapeptide of equine angiotensinogen resulted in greatly increased binding affinity and resistance to cleavage by renin. The D-His6-Tyr13 octapeptide analog containing the reduced bond -CH2-NH-instead of a peptide bond -CO-NH- at the Leu10-Leu11 linkage (H-77) was a powerful in vitro inhibitor of canine renin (IC50 = 24nM). It gave an IC50 of 1 microM against human renin and 0.6 microM against rat renin. In sodium-depleted conscious dogs, infusion of H-77 caused dose-related falls of plasma angiotensin I plasma angiotensin II concentration and mean arterial pressure; the minimum effective dose was 0.1 mg . kg-1 hr-1. Similar infusions of H-77 in chronically catheterized rats have no effect on blood pressure or plasma angiotensin II concentration. Thus, the in vitro effect of H-77 as an inhibitor of renin in dog, human, and rat plasma was paralleled by its action in the whole animal.

Angiotensin I↗