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Biomedical subjects

E Naylor

Publications and source records attributed to E Naylor.

11 recordsLinked to original sources

The management of persistent or recurrent variceal bleeding after injection sclerotherapy by somatostatin.

Sixteen patients with persistent (n = 11) or recurrent (n = 5) variceal bleeding after injection sclerotherapy and balloon tamponade were treated with an intravenous infusion of somatostatin 250 micrograms/h. Somatostatin infusion successfully controlled the bleeding in 15 of the 16 patients but one rebled after 72 h of treatment. In one patient with poor liver function (Child's C) bleeding was not controlled by somatostatin, further injection sclerotherapy or balloon tamponade of the oesophagus. The results of this study, although uncontrolled and with a small number of patients, suggest that somatostatin is a very effective treatment for the control of post-injection sclerotherapy variceal bleeding.

Adult

The management of gastrointestinal haemorrhage by somatostatin after apparently successful endoscopic injection sclerotherapy for bleeding oesophageal varices.

Twenty-two patients who experienced a severe haemorrhage from either oesophagitis (n = 8) or ulcers (n = 14) following injection sclerotherapy of their oesophageal varices were treated with intravenous administration of somatostatin (250 micrograms/h). Somatostatin was effective in controlling haemorrhage and preventing rebleeding in all eight patients bleeding from oesophagitis and in 12 of the 14 patients bleeding from oesophageal ulcers. In two patients with ulcers, haemorrhage persisted despite two periods of concominant balloon tamponade and somatostatin infusion and bleeding was eventually controlled by repeated hourly bolus injections of the hormone for 24 h superimposed on the continuous infusion. The results of this study suggest that somatostatin is an effective and safe treatment for the control of bleeding from either oesophagitis or ulcers following injection sclerotherapy of oesophageal varices.

Combined Modality Therapy

Effects of cold exposure on rat adrenal tyrosine hydroxylase: an analysis of RNA, protein, enzyme activity, and cofactor levels.

Long-term cold exposure (5-7 days) is known to induce concomitant increases in the levels of adrenomedullary tyrosine hydroxylase (TH) RNA, protein, and enzyme activity. In this report, we compare the time courses of these changes and investigate the effects of cold exposure on the levels of biopterin, the cofactor required for tyrosine hydroxylation. After only 1 h of cold exposure, TH mRNA abundance increased 71% compared with nonstressed controls. Increases in total cellular TH RNA levels were maximal (threefold over control values) within 3-6 h of cold exposure and remained elevated throughout the duration of the experiment (72 h). TH protein levels increased rapidly after 24 h of cold exposure and reached a maximal value threefold above that of controls at 48-72 h. Despite the relatively rapid and large elevations in TH RNA and protein content, only modest increases in TH activity were detected during the initial 48 h of cold exposure. Adrenomedullary biopterin increased rapidly after the onset of cold exposure, rising to a level approximately twofold that of the nonstressed controls at 24 h, and remained at this level throughout the duration of the stress period. Taken together, the results of this time course study indicate that cold-induced alterations in adrenal TH activity are mediated by multiple cellular control mechanisms, which may include pre- and posttranslational regulation. Our findings also suggest that cold stress-induced increases in the levels of the TH cofactor may represent another key event in the sympathoadrenal system's response to cold stress.

Adrenal Glands

Entrainment of bimodal circatidal rhythms in the shore crab Carcinus maenas.

Individuals of the shore crab Carcinus maenas were exposed to artificial cycles, applied in tidal antiphase, of pairs of the three major environmental variables that entrain circatidal rhythmicity in this species: salinity, temperature, and hydrostatic pressure. During entrainment, the observed locomotor activity patterns were dominated by exogenous responses to high pressure, low temperature, or low salinity. In subsequent constant conditions, many of the crabs showed bimodal circatidal rhythms, with peaks phased to the times of expected high-tide characteristics of high pressure, low temperature, or high salinity. Similar bimodal rhythms were induced by exposing freshly captured crabs, with free-running circatidal rhythms, to tidal antiphase cycles of each of the three environmental variables applied individually. The hypothesis that circatidal rhythmicity in this species is controlled by at least two separate circatidal oscillators, with differential sensitivities to specific cyclical environmental variables, is discussed.

Animals

An estimation of doses received by patients in a diagnostic x-ray department.

This article describes a method of estimating the effective dose equivalent received by patients undergoing (non-fluoroscopic) diagnostic x-ray examinations. This allows those clinically or physically directing exposures to comply with the requirement, item 3, in the core knowledge contained in the schedule of the health and safety document number 778. The method described can be carried out without the use of expensive equipment or time consuming procedures and is based on the data contained in the publication NRPB R200. This method does not conflict with that described by Shrimpton in Radiography Today but is an alternative approach.

Female

Fish farming and influenza pandemics.

Human influenza pandemics commonly arise by genetic reassortment between human and avian viruses in pigs. Yet global developments in aquaculture--the so-called 'Blue Revolution'--will mean increased co-location of people, ducks and pigs.

Animal Husbandry

Tidally rhythmic behaviour of marine animals.

The best general hypothesis for the control of 'spontaneous' tidal and daily patterns of behaviour in coastal animals postulates an endogenous physiological pacemaker system which generates approximate periodicity, together with environmental adjustment of the clock(s) to local time. Free-running endogenous rhythms of circatidal, circadian, circasemilunar and circalunar periodicity have been demonstrated in a number of species in constant laboratory conditions, in some cases clarifying hitherto poorly understood aspects of the behavioural repertoire of animals in the sea. Entrainment of circatidal rhythmicity has been demonstrated using cycles of simulated tidal variables such as temperature, hydrostatic pressure, salinity and wave action. The crab Carcinus shows increased locomotor activity after changes of salinity (halokinesis); responses to 34% salinity entrain the endogenous clock, but responses to salinities above or below 34% are purely exogenous and do not persist in constant conditions after entrainment. Phase responsiveness of circatidal rhythms to pulses of tidal variables has been demonstrated in several species; phase response curves show marked differences from those of circadian rhythms. The endogenous basis of tidal and diel behaviour in marine molluscs and crustaceans involves matching spontaneous rhythms of neuroelectrical activity. Also, in decapod crustaceans a peptidic neurodepressing hormone (NDH) modulates neuroelectrical and behavioural rhythmicity. NDH is produced rhythmically in the eyestalk neurosecretory complex, perhaps partly under the control of other clock components elsewhere in the CNS. The physiological basis of circasemilunar, lunar (and annual) rhythms of behaviour has not been studied, but studies of synchronization of these rhythms have been undertaken. In some localities it has been shown experimentally that light intensities equivalent to moonlight are sufficient to entrain such rhythms. In other localities where moonlight is a less reliable cue the relative timing of tidal and daily variables has been shown to be important. So far there is no evidence that synchronization is achieved by absolute differences between tidal variables at neap and spring tides.

Activity Cycles