Evaluation of housing as a means to protect cattle from Culicoides biting midges, the vectors of bluetongue virus.

The housing of animals at night was investigated as a possible means of protecting them from attack by Culicoides biting midges (Diptera: Ceratopogonidae), the vectors of bluetongue. Light-trap catches of Culicoides were compared inside and outside animal housing, in the presence and absence of cattle. A three-replicate, 4 x 4 Latin square design was used at four farms in Bala, north Wales, over 12 nights in May and June 2007, and the experiment repeated in October. In the two studies, respectively, >70 000 and >4500 Culicoides were trapped, of which 93% and 86%, respectively, were of the Culicoides obsoletus group. Across the four farms, in May and June, the presence of cattle increased catches of C. obsoletus by 2.3 times, and outside traps caught 6.5 times more insects than inside traps. Similar patterns were apparent in October, but the difference between inside and outside catches was reduced. Catches were strongly correlated with minimum temperature and maximum wind speed and these two variables explained a large amount of night-to-night variation in catch. Outside catches were reduced, to a greater extent than inside catches, by colder minimum temperatures and higher maximum wind speeds. These conditions occur more frequently in October than in May and June, thereby suppressing outside catches more than inside catches, and reducing the apparent degree of exophily of C. obsoletus in autumn. The results suggest that the risk of animals receiving bites from C. obsoletus is reduced by housing at both times of year and the benefit would be greatest on warm, still nights when outside catches are at their greatest.

Intravenous lactate prevents cerebral dysfunction during hypoglycaemia in insulin-dependent diabetes mellitus.

1. Intravenous lactate prevents cerebral dysfunction during hypoglycaemia in healthy volunteers. This study examines whether this also occurs in insulin-dependent diabetes. Changes in four-choice reaction time, auditory brain stem response, and P300 latency were used as measures of cerebral function. 2. Ten subjects were studied twice at least 4 weeks apart. Blood glucose was maintained between 5 and 8 mmol/l for 1 h before starting a 60 m-unit min-1 m-2 stepped hyperinsulinaemic clamp, achieving blood glucose concentrations of 4.5, 3.3 and 2.5 mmol/l. At one visit, 40 mumol min-1 kg-1 sodium lactate was infused, and at the other, normal saline. Cerebral function was measured at each blood glucose concentration. 3. Blood lactate rose to 3.32 +/- 0.06 mmol/l during lactate infusion compared with 0.9 +/- 0.03 mmol/l during saline infusion. Compared with the results at 4.5 mmol/l there were no significant changes at 3.3 mmol/l in any measure of cerebral function at either visit. At 2.5 mmol/l a significant increase in reaction time and P300 latency occurred with saline [mean change 33.1 +/- 8.6 ms (P < 0.01) and 30.1 +/- 9.2 ms (P < 0.01) respectively] but not lactate [mean change -5.9 +/- 3.7 ms (P > 0.05) and -6 +/- 7.6 ms (P > 0.05) respectively]. No significant changes occurred in auditory brain stem response. The catecholamine response to hypoglycaemia was attenuated by lactate (P < 0.05 for adrenaline and noradrenaline). 4. Thus intravenous lactate prevents cerebral dysfunction during hypoglycaemia in insulin-dependent diabetes.

Well-being, cerebral function, and physical fatigue after nocturnal hypoglycemia in IDDM.

OBJECTIVE: This study assessed the effect of nocturnal hypoglycemia on well-being cerebral function, and physical fatigue the next day in 10 subjects with IDDM. RESEARCH DESIGN AND METHODS: After an exercise test to determine work-loads corresponding to 30 and 60% VO2max, volunteers were studied twice, 4 weeks apart. Blood glucose was lowered one night to 2.3-2.7 mmol/l for 1 h, and at the control visit, hypoglycemia was avoided. The next morning, well-being was assessed using the minor symptom evaluation profile (MSEP), and cerebral function was assessed with the paced auditory serial addition test, the digit symbol substitution test, trail making part B, four-choice reaction time, and auditory P300 latency. Subjects then exercised at predetermined workloads corresponding to 30% VO2max for 30 min and 60% VO2max until exhaustion. Fatigue was assessed every 10 min using the Borg scale for rating of perceived exertion. RESULTS: All three components of the MSEP scored higher (indicating more symptoms) after the hypoglycemic night compared with the control night (P < 0.01 contentment, sleep; P < 0.001 vitality). None of the cerebral function tests performed the next day was affected by hypoglycemia. Exercise capacity was similar at both visits, but subjects were more fatigued after the hypoglycemic night (P < 0.01, analysis of variance). There were no differences in potassium, catecholamine, glucose, or lactate concentrations between visits either before or during exercise. CONCLUSIONS: One hour of hypoglycemia at night affects a subject's sense of well-being, but not cerebral function, the next day. The greater fatigue after the hypoglycemic night cannot be explained by the biochemical parameters measured.

The effect of intravenous lactate on cerebral function during hypoglycaemia.

Any factor which protects the brain against hypoglycaemia induced cerebral dysfunction could have important therapeutic implications for intensive insulin therapy. This study tested the hypothesis that intravenous lactate protects cerebral function during hypoglycaemia. Four choice reaction time, Auditory Brain Stem Response (ABR), and P300 latency were used as measures of cerebral function. Nine healthy volunteers (six female) underwent two stepped hyperinsulinaemic clamps at least 4 weeks apart, achieving blood glucose levels of 4.5, 3.3, and 2.5 mmol l-1. On one occasion 40 mumol kg-1 min-1 sodium lactate was infused, and on the other, normal saline. Cerebral function tests were measured at each glucose level. At 3.3 mmol l-1, there was a significant slowing of four choice reaction time with saline (p < 0.02) but not with lactate; no changes in P300 latency or ABR occurred on either occasion. At 2.5 mmol l-1 results from all three tests deteriorated significantly during saline infusion (p < 0.001 reaction time, p < 0.02 ABR and p < 0.05 P300), but not lactate. Lactate infusion was associated with a reduction in noradrenaline (p < 0.05), adrenaline (p < 0.05), and growth hormone (p < 0.02) responses at a glucose of 2.5 mmol l-1. These results support the hypothesis that intravenous lactate protects cerebral function during hypoglycaemia.

Antecedent hypoglycaemia in non-diabetic subjects reduces the adrenaline response for 6 days but does not affect the catecholamine response to other stimuli.

1. Recent hypoglycaemia reduces the counter-regulatory and symptomatic response to the next episode of hypoglycaemia. This study was designed to determine whether antecedent hypoglycaemia (a) affected the sympathoadrenal response to other stimuli (postural change and a mathematical stress test, (b) was associated with adaptation of cognitive function and (c) if avoided for 6 days led to the restoration of the counter-regulatory response to hypoglycaemia. 2. On the morning of day 1, 10 healthy men had their response to the sympathoadrenal stimuli assessed before an episode of hypoglycaemia (2.5 mmol/l). A further hyperinsulinaemia clamp was performed for 2h (blood glucose 3.0 mmol/l or 5.0 mmol/l) in the afternoon and the assessments repeated the next day and 6 days later. Cognitive function using the four-choice reaction time test was assessed before and during the episodes of morning hypoglycaemia. The whole study was repeated 4 weeks later with the other afternoon glucose level. 3. Adrenaline levels and sweat rates were reduced (P < 0.05) on day 2 during hypoglycaemia on both occasions and had not returned to normal after 6 days. Symptom scores were lower (P < 0.05) only on day 2 after the afternoon of hypoglycaemia. The responses to the sympathoadrenal stimuli and cognitive function were unaffected by antecedent hypoglycaemia. 4. The adaptation of the counter-regulatory response to antecedent hypoglycaemia appears to be specific to hypoglycaemia. The response takes longer than 6 days but less than 4 weeks to return to normal. Antecedent hypoglycaemia does not lead to cerebral adaptation.

Physiological response to postural change during mild hypoglycaemia in patients with IDDM.

It has been suggested that patients with insulin-dependent diabetes mellitus may be less aware of impending hypoglycaemia when lying than standing. We have studied the effect of posture and duration of hypoglycaemia on symptoms and physiological responses in 10 men with insulin-dependent diabetes. A standard tilting protocol was used (supine, 50 degrees, 90 degrees headup, and return to supine, 5 min at each position). At one visit patients were tilted before, 10 min after and 40 min after achieving hypoglycaemia (blood glucose 2.5 mmol/l), and at another visit were tilted after euglycaemia (5.0 mmol/l) using a hyperinsulinaemic clamp. At each position, hormonal and physiological responses and symptoms (using visual analogue scales) were recorded. After 10 min of hypoglycaemia, adrenaline was significantly higher when 90 degrees headup compared with supine (mean [+/- SEM] 6.26 [+/- 1.88] vs 1.68 [+/- 0.4] nmol/l; p < 0.05), and fell significantly (to 2.46 [+/- 0.65] nmol/l; p < 0.05) when returned to supine; sweating, symptom score and blood pressure followed a similar pattern. After 40 min of hypoglycaemia a similar effect of standing was seen on sweating, adrenaline and blood pressure but symptoms did not increase. Five patients underwent two further periods of hypoglycaemia, remaining supine or standing throughout. Face skin blood flow (p < 0.05) and temperature (p = 0.05) decreased when standing was maintained compared with lying. In conclusion, standing increases awareness of early hypoglycaemia and modifies many of the physiological changes. This increase in awareness is lost if hypoglycaemia is prolonged.

Metabolic effects of acute hyperketonaemia in man before and during an hyperinsulinaemic euglycaemic clamp.

1. The effects of acutely raising blood ketone body levels to those seen after 72 h of starvation were examined in 10 subjects after an overnight fast. Metabolic rate and respiratory exchange ratio were measured with indirect calorimetry before and during an insulin-glucose clamp. Arteriovenous differences were measured across forearm and subcutaneous abdominal adipose tissue. 2. In response to the clamp the respiratory exchange ratio rose from 0.82 to 0.83 during 3-hydroxybutyrate infusion and from 0.83 to 0.94 during control (saline) infusion (P < 0.001). 3. Forearm glucose uptake at the end of the clamp was 4.02 +/- 0.95 (3-hydroxybutyrate infusion) and 7.09 +/- 1.24 mmol min-1 100 ml-1 forearm (saline infusion). Whole body glucose uptake at the end of the clamp was 72.8 +/- 7.9 (3-hydroxybutyrate infusion) and 51.0 +/- 3.0 (saline infusion) mmol min-1 kg-1 body weight-1. 4. 3-Hydroxybutyrate infusion reduced the baseline abdominal venous-arterialized venous glycerol difference from 84 +/- 28 to 25 +/- 12 mmol/l and the non-esterified fatty acid difference from 0.60 +/- 0.17 to 0.02 +/- 0.09 mmol/l (P < 0.05 versus saline infusion). 5. Hyperketonaemia reduces adipose tissue lipolysis and decreases insulin-mediated forearm glucose uptake. Hyperketonaemia appears to prevent insulin-stimulated glucose oxidation, but does not reduce insulin-mediated glucose storage.

The effect of educational brochures on knowledge and emotional distress in women with abnormal Papanicolaou smears.

OBJECTIVE: To determine whether an educational brochure about abnormal Papanicolaou smears could reduce psychological distress and concerns about cancer and future health, and increase knowledge about dysplasia and the investigation, treatment, and recommended follow-up. METHODS: One hundred twenty-five consecutive women with dysplasia on a Papanicolaou smear referred to a colposcopy clinic for their first examination were alternately assigned to receive a mailed educational brochure the same day or to receive no brochure. At the colposcopy clinic, consenting women were given the Brief Symptom Inventory, specific questions about feelings regarding an abnormal smear, and a knowledge quiz about dysplasia, colposcopy, and the recommended follow-up. RESULTS: Women who received the brochure were significantly less distressed on the Brief Symptom Inventory and were less anxious about the abnormal Papanicolaou smear, the fear of cancer, and their future health than were women not receiving the brochure. Study women also performed significantly better on knowledge questions about dysplasia, colposcopy, and the recommended follow-up. CONCLUSION: Given the low cost, ease of delivery, and usefulness of educational brochures in reducing psychological distress and increasing knowledge specific to the condition, an educational brochure should routinely accompany or immediately follow notification about an abnormal Papanicolaou smear.

Focus on Trent: management. Developing nurse management skills.

Within a climate of change in the National Health Service and in recognition of the management function of nurses, Trent Region introduced a 'fast-track' development initiative to prepare nurses to fulfil new managerial roles. Two self-managed action learning programmes were conducted: one for nurses who would be functioning at clinical directorate or equivalent level, and another for those at executive board level. The author argues that the programme has proved itself as an enabling process for all of the participants.