Atrioventricular plane displacement and regional contribution to stroke volume to predict outcome in pulmonary arterial hypertension

Background

Patients with pulmonary arterial hypertension (PAH) exhibit high mortality, partially related to right heart failure. Right ventricular (RV) volumes and ejection fraction (EF) can be measured accurately with cardiac magnetic resonance (CMR), but EF is a crude measure of cardiac function. Additional methods for risk assessment and prognosis are of value. Stroke volume (SV) is generated by longitudinal, lateral and septal myocardial contraction. Longitudinal contribution to SV (SVlong%) generated from the atrioventricular displacement (AVPD) is the major contributor to SV in both the left ventricle (LV) and RV. AVPD in both sides and LVSVlong% are lower in patients with PAH compared to controls. However, it is unknown if altered AVPD or regional contributions to SV are prognostic in patients with PAH. The aim of this study was therefore to evaluate if AVPD, longitudinal, lateral or septal contribution to LVSV and RVSV are associated with death or lung transplantation in patients with PAH.

Purpose

To evaluate if biventricular AVPD, and regional contributions to SV are associated with outcome in patients with PAH.

Methods

Seventy-one patients with PAH and 20 sex and age-matched healthy controls underwent CMR. Endocardial and epicardial borders and RV insertion points were defined in end diastole and end systole in cine short-axis stacks to compute biventricular volumes, SVlat% and SVsept%. Eight atrioventricular points were defined in end diastole and end systole in 2-, 3- and 4-chamber cine long-axis views, for computation of AVPD and SVlong%. Cut-off values for survival analysis were defined as above or below mean ± 2 standard deviations from the healthy controls. Outcome was defined as death or lung-transplantation.

Results

Median follow-up time was 3.6 [IQR 3.7] years. AVPD, SVlong%, SVlat% in both ventricles and SVsept% were altered in PAH compared to controls. Transplantation-free survival was lower with values below cut-off for LV-AVPD (hazard ratio (HR)=2.1, 95% CI: 1.2–3.9, p=0.02) and RV-AVPD (HR=9.8, 95% CI: 4.6–21.1, p=0.005) (fig 1). In cox regression analysis, decreased LV-AVPD and RV-AVPD inferred lower transplantation-free survival (LV: HR=1.16 per mm decrease, p=0.007; RV: HR=1.11 per mm decrease, p=0.01) (table 1). LVEF, RVEF, LV-SVlong%, RV-SVlong%, LV-SVlat%, RV-SVlat% or SVsept% did not affect outcome (table 1).

Conclusions

Decreased left and right AVDP were associated with decreased transplantation-free survival in patients with PAH. There were no associations between ejection fraction, longitudinal, lateral or septal contribution to stroke volume.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Skåne University Hospital, Region of Skåne Southern Healthcare Region of Sweden

Incident depression in patients diagnosed with multiple sclerosis: a multi-database study

BACKGROUND AND PURPOSE

Data on rates of newly diagnosed depression after multiple sclerosis (MS) diagnosis are sparse. Here, incident, treated depression in MS patients after diagnosis compared with matched non-MS patients is described.

METHODS

A matched cohort study was conducted in two separate electronic medical databases: the US Department of Defense (US-DOD) military healthcare system and the UK's Clinical Practice Research Datalink GOLD (UK-CPRD). The study population included all patients with a first recorded diagnosis of MS and matched non-MS patients. Patients with a history of treated depression were excluded. Incidence rates and incidence rate ratios with 95% confidence intervals for treated depression after MS diagnosis/matched date were estimated.

RESULTS

Incidence rate ratios of treated depression amongst MS patients compared with non-MS patients were 3.20 (95% confidence interval 3.05-3.35) in the US-DOD and 1.90 (95% confidence interval 1.74-2.06) in the UK-CPRD. Incidence rate ratios were elevated across age and sex. Rates were higher in females than males but, compared to non-MS patients, males with MS had a higher relative risk than females with MS.

CONCLUSIONS

Multiple sclerosis patients in the UK and the USA have a two- to three-fold increased risk of new, treated depression compared to matched non-MS patients.

Infections in patients diagnosed with multiple sclerosis: A multi-database study

BACKGROUND

Recent data on the rates of infections among patients with multiple sclerosis (MS) are sparse. The objective of this study was to quantify incidence of infections in patients with MS compared with a matched sample of patients without MS (non-MS).

METHODS

This study was conducted in two separate electronic medical databases: the United States Department of Defense (US-DOD) military health care system and the United Kingdom's Clinical Practice Research Datalink GOLD (UK-CPRD). We identified patients with a first recorded diagnosis of MS between 2001 and 2016 (UK-CPRD) or 2004 and 2017 (US-DOD) and matched non-MS patients. We identified infections recorded after the MS diagnosis date (or the matched date in non-MS patients) and calculated incidence rates (IRs) and incidence rate ratios (IRRs) with 95% confidence intervals (CIs) by infection site and type.

RESULTS

Relative to non-MS patients, MS patients had higher rates of any infection (US-DOD IRR 1.76; 95% CI 1.72-1.80 and UK-CPRD IRR 1.25; 95% CI 1.21-1.29) and a two-fold higher rate of hospitalized infections (US-DOD IRR 2.43; 95% CI 2.23-2.63 and UK-CPRD IRR 2.00; 95% CI 1.84-2.17). IRs of any infection were higher in females compared with males in both MS and non-MS patients, while IRs of hospitalized infections were similar between sexes in both MS and non-MS patients. The IR of first urinary tract or kidney infection was nearly two-fold higher in MS compared with non-MS patients (US-DOD IRR 1.88; 95% CI 1.81-1.95 and UK-CPRD IRR 1.97; 95% CI 1.86-2.09) with higher rates in females compared with males. IRs for any opportunistic infection, candidiasis and any herpes virus were increased between 20 and 52% among MS patients compared with non-MS patients. IRs of meningitis, tuberculosis, hepatitis B and C were all low.

CONCLUSION

MS patients have an increased risk of infection, notably infections of the renal tract, and a two-fold increased risk of hospitalized infections compared with non-MS patients.

Reduced training distance and a forage-only diet did not limit race participation in young Standardbred horses

In this study, a survey was used to document the type and amount of training to which 2- to 3-year old Swedish Standardbred horses are generally subjected. Moreover, an experimental study was conducted to examine the ability to achieve conventional performance goals in 16 Standardbred geldings fed a forage-only diet and allocated to either a control training programme (C-group) or a training programme with the high intensity training distance reduced by 30% (R-group) from March as 2-year-olds until December as 3-year-olds. The median distance of high intensity training per week reported by professional trainers was 6,700 m. In experimental horses, planned high intensity training/week was 6,315 and 4,288 m in C-group and R-group, respectively. There was no difference between experimental training groups in ability to race. The proportion of experimental horses that passed a preparation race as 2-year-olds (100%) and qualified for races (94%) was greater (P<0.05) than for the rest of the cohort (77 and 63%), geldings of the same cohort (71 and 45%) and siblings of the experimental horses (84 and 69%). The proportion of horses that raced (56%) was equal to that of the cohort and of siblings (54%), but greater than the proportion of cohort geldings (35%, P<0.05). In experimental horses, total earnings until 7 years of age were correlated to exercise haematocrit as 3-year-olds (r=0.51, P>0.05) and number of races (r=0.55, P>0.05). Race record was correlated to VLa4 as 3-year-olds (r=-0.75, P<0.01). It was concluded that a forage-only diet and shorter distance of high intensity training than commonly used in Standardbred training in Sweden do not appear to restrict ability to qualify for races and race before 4 years of age.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Curriculum vitae paper - Sune G.B. Persson (1931-2009)

Sune Persson was born in Landskrona Sweden in 1931 and grew up on the west coast of Sweden. He graduated from the Royal Veterinary College in Stockholm in 1960 and in 1967 received his PhD entitled ‘On blood volume and working capacity in horses’. Sune pursued an academic career devoted to internal medicine and exercise physiology. He rapidly became Professor of Medicine in 1979 as the veterinary school moved from Stockholm to the Swedish University of Agricultural Sciences in Uppsala.

Subtypes of Hepatitis B Antigen in Blood Donors and Post-transfusion Hepatitis: Clinical and Epidemiological Aspects

Subtyping of hepatitis B antigen (HBA) in blood donors revealed subtype ad in 56% while patients with icteric post-transfusion hepatitis from the same centre showed subtype ay in the majority of the cases (75%). Donors with subtype ad in serum were mostly asymptomatic long-term carriers of the antigen with normal liver function (83%), while 70% of donors with subtype ay in serum had signs of acute or chronic liver disease. Healthy long-term carriers of HBA seem to present little risk of transmitting hepatitis irrespective of subtype. It is, however, possible that these differences in blood donors with subtype ad and patients with post-transfusion hepatitis with subtype ay might reflect epidemiological circumstances rather than biological differences in the two viral strains.

The Opioid Haemorphin-7 in Horses During Low-speed and High-speed Treadmill Exercise to Fatigue

The opioid neuropeptide haemorphin-7 was measured, by immunoreactivity, in Standardbred horses during low-speed (7 m/s) and high-speed (10 m/s) endurance exercises, lasting 49-58 and 12-16 min respectively. In parallel, heart rate, muscle temperature and plasma lactate concentrations were measured. The profile of the low-speed exercise showed significantly increased heart rate after 10 min [154 beats per minute (bpm)]. After the exercise, muscle temperature (42.1 degrees C) and plasma lactate (4.8 mmol/l) were significantly increased. The profile of the high-speed exercise was comparatively characterized by a higher increase of heart rate after 5 min (194 bpm) and higher increases of muscle temperature (43.2 degrees C) and lactate levels (15.8 mmol/l) after the exercise. The horses were probably exhausted by glycogen depletion in the low-speed exercise and by muscle pH decrease in the high-speed exercise. Haemorphin-7 increased significantly during the high-speed exercise (274.8 fmol/ml) but not during low speed (108.3 fmol/ml), coincident with the results of lactate. These results suggest that plasma haemorphin-7 is measurable in the horse by immunoreactivity, and that intense exercise stimulates release of this opioid. Such endogenous opioids are most likely involved in regulatory functions associated with pain, physical effort, inflammation, and blood pressure variation in horses, as have been established in other species.

Insulin aspart: a novel rapid-acting human insulin analogue

In order to improve therapy and increase the quality of life for diabetic patients, it has been of significant interest to develop rapid-acting insulin preparations that mimic the physiological meal-time profile of insulin more closely than soluble human insulin. Insulin aspart (B28Asp human insulin) is a novel rapid-acting insulin analogue that fulfils this criterion. The B28Asp modification weakens the self-association of the insulin molecule and provides a more rapid absorption from the sc. injection site. The preclinical evaluation in vitro and in vivo demonstrates that apart from the more rapid absorption, insulin aspart is equivalent to human insulin. Thus, insulin aspart is equivalent to human insulin on key in vitro parameters such as insulin receptor affinity, insulin receptor dissociation rate, insulin receptor tyrosine kinase activation, IGF-I receptor binding affinity, metabolic and mitogenic potency. In accordance with the equivalent in vitro profiles, the toxico-pharmacological properties of insulin aspart and human insulin are also identical. The available data for insulin aspart and other rapid-acting insulin analogues supports that in vitro assays are sensitive and valuable in the preclinical evaluation of insulin analogues. Clinical studies demonstrate that insulin aspart has a pharmacokinetic and pharmacodynamic profile superior to that of soluble human insulin. In Type 1 diabetic patients on a basal-bolus injection regimen, insulin aspart given immediately before the meals provides an improved postprandial glycaemic control and an improved long-term metabolic control, as compared to soluble human insulin given 30 min before the meals, without increasing the risk of hypoglycaemia. Taken together, the data support the hope that insulin aspart will allow the diabetic patient to combine a more flexible lifestyle with better glycaemic control, without any increased safety risk.

Hypoglycaemia with insulin aspart: a double-blind, randomised, crossover trial in subjects with Type 1 diabetes

AIMS

To compare the effects of the rapid-acting insulin analogue insulin aspart and soluble human insulin on hypoglycaemia and glycaemic control in patients with Type 1 diabetes when injected immediately before meals as part of intensive insulin therapy.

METHODS

In this multinational, double-blind, randomised, crossover trial, 155 patients with Type 1 diabetes (HbA(1c) < 8.0%) were symmetrically randomised to two 16-week treatment periods on either type of insulin, both injected 0-5 min before meals. NPH insulin was given as basal insulin once or twice daily as needed, and insulin dosages were regularly adjusted using pre-defined algorithms to maintain tight glycaemic control. Treatment periods were separated by a 4-week washout.

RESULTS

The rate of major nocturnal (24.00-06.00 h) hypoglycaemic episodes was 72% lower with insulin aspart than with human insulin (0.067 vs. 0.225 events/month; P = 0.001). Total rate of major hypoglycaemia did not differ significantly between treatments (insulin aspart/human insulin relative risk 0.72; 95% CI 0.47-1.09, P = 0.12). The rate of minor events was significantly reduced by 7% with insulin aspart (P = 0.048). Reductions in rate of hypoglycaemia were achieved with maintained overall glycaemic control: Mean HbA(1c) remained constant, slightly below 7.7% on both treatments.

CONCLUSIONS

The use of insulin aspart in an intensive insulin regimen in patients with tightly controlled Type 1 diabetes led to clinically significant reductions in major nocturnal hypoglycaemia with no deterioration in glycaemic control. Major nocturnal hypoglycaemia appears to be a strong clinical indication for the use of rapid-acting insulin analogues during intensive insulin therapy.

Comparison of thrice daily 'high' vs. 'medium' premixed insulin aspart with respect to evening and overnight glycaemic control in patients with type 2 diabetes

BACKGROUND

The glycaemic control of thrice daily treatment with premixed biphasic insulin aspart (BIAsp) without other antidiabetic therapy was tested in type 2 diabetic patients, in order to compare the glucose control of a 'high' mixture (BIAsp 70) or a 'medium' mixture (BIAsp 50) (70 or 50% soluble IAsp and 30 or 50% protamine-crystallized IAsp, respectively) administered just before dinner.

AIM

To compare these regimens to conventional 30 : 70 premixture on a twice a day basis.

METHODS

This randomized, double-blind, two-period crossover study included 16 patients with type 2 diabetes. Twenty four-hour serum glucose and insulin profiles were obtained thrice: (1) after a one-week run-in period with biphasic human insulin (BHI) 30/70 twice daily (run-in), (2) after 4 weeks of treatment with thrice daily BIAsp 70 before breakfast, lunch and dinner (Dinner70 regimen) and (3) after 4 weeks of BIAsp 70 before breakfast and lunch and BIAsp 50 before dinner (Dinner50).

RESULTS

Daytime average serum glucose was lower with Dinner70 compared to run-in (9.6 +/- 0.39 mmol/l vs. 11.2 +/- 0.61 mmol/l, p < 0.05). Postprandial glucose excursions after breakfast and lunch were lower, but fasting morning glucose was higher during the treatment periods than in the run-in period. Twenty four-hour C-peptide AUC was considerably lower during both treatment periods than in the run-in period (run-in/Dinner50 ratio 1.29 [1.08; 1.54] p < 0.01; run-in/Dinner70 ratio 1.31 [1.08;1.58], p < 0.01).

CONCLUSIONS

Switching the dinner dose to BIAsp 50 did not alter overall glucose control significantly from that provided with BIAsp 70. Exploratory analyses between the two active treatment regimens and run-in/BHI indicate that thrice daily BIAsp 70 administration: (1) for optimization of the night-time control, the dinner dose needs adjustment or replacement by a premixed insulin with a larger proportion of basal insulin than BIAsp 50 and (2) none of the premixtures adequately provide for both the evening meal and overnight requirements.

A randomized trial of insulin aspart with intensified basal NPH insulin supplementation in people with Type 1 diabetes

AIMS

Insulin aspart has been shown to improve post-prandial and overall glycaemic control in people with Type 1 diabetes. We hypothesized that insulin aspart with intensified basal NPH insulin supplementation would result in better overall glycaemic control than human regular insulin with standard basal NPH insulin.

METHODS

The trial was conducted in 43 centres in seven countries. People with Type 1 diabetes were randomized to mealtime insulin aspart with up to four daily NPH doses if meals were > 5 h apart and a 25% increase in bedtime NPH dose (n = 187), or to mealtime human unmodified insulin with once or twice daily basal NPH insulin (n = 181). Efficacy and safety were evaluated at 12 weeks (primary evaluation period) and 64 weeks.

RESULTS

At 12 and 64 weeks there was no statistically significant difference in HbA1c between the insulin aspart and regular insulin groups: -0.09 (95% confidence interval (CI) -0.23, +0.05)% and -0.14 (-0.32, +0.04)%. Post-prandial glucose values were lower and the area under the 24-h self-monitored blood glucose curve above 7.0 mmol/l was 28% smaller with insulin aspart (35.2 +/- 3.2 vs. 48.9 +/- 3.1 mmol/l h, P = 0.0015). No significant differences were found in mild or severe hypoglycaemia, or adverse event rate. At 64 weeks treatment satisfaction was higher in the insulin aspart group (difference 1.57 (95% CI 0.49, 2.64) points, P = 0.004), while quality of life was not different.

CONCLUSIONS

Improved post-prandial glycaemic control and treatment satisfaction with insulin aspart were confirmed. Intensifying basal insulin supplementation resulted in a similar HbA1c decrement as previously found with the use of insulin aspart and standard NPH insulin supplementation. This does not support routinely basal NPH insulin intensification when using rapid-acting insulin analogues in daily practice.

Effects on exercise metabolism of varying dietary starch and sugar proportions

Studies of the effect of varying dietary carbohydrate compositions on exercise metabolism of horses are scarce. In the present study, the starch and sugar proportions were altered in the diet to 4 Standardbred horses. In a crossover experiment, the horses were offered a hay and oat diet, where the oats were substituted for barley syrup (BS) at 4 levels (BS 0, 0.5, 1.0 and 1.5 kg). Each diet was consumed for 21 days and both an incremental treadmill exercise test (IE) and a 40 min submaximal exercise test (SE) were performed. During the IE there was a significant (P<0.05) increase in mean VO2 on BS 1.5 and at the highest speed respiratory exchange ratio (RER) was significantly lower on BS 1.0 and 1.5. During the SE, RER and HR were significantly higher on BS 1.0 and 1.5. There were no significant effects of diets on plasma levels of glucose, lactate and insulin. Following the SE there was a significant decrease in the muscle glycogen content on BS 0, which was not observed in the other diets. In addition, there was a numerical decrease in the glycogen utilisation with increasing proportions of sugar in the diet. In conclusion, this study indicates that horses on diets with a high sugar inclusion respond with an increased heart rate during exercise of lower intensities; and that the response in VO2 and RER may differ depending on the exercise intensity. In addition, glycogen utilisation during submaximal exercise was lowered when daily sugar intake was increased. However, further investigation is needed to evaluate whether this strategy of feeding could be beneficial for exercising horses competing over endurance distances.

Premixed insulin aspart 30 vs. premixed human insulin 30/70 twice daily: a randomized trial in Type 1 and Type 2 diabetic patients

AIM

To compare the efficacy and safety of premixed insulin aspart (30% free and 70% protamine-bound, BIAsp 30) with human insulin premix (BHI 30) used in a twice-daily injection regimen in people with Type 1 and Type 2 diabetes.

METHODS

People with Type 1 and Type 2 diabetes (n = 294) using twice-daily insulin were randomized to a 12-week open-label comparison of BIAsp 30 and BHI 30. Efficacy was assessed by analysis of variance of 12-week data, adjusted for baseline level.

RESULTS

BIAsp 30 was as effective as BHI 30 based on the primary efficacy measure, HbA1c, mean difference -0.01 (90% confidence interval (CI) -0.14; 0.12) %Hb. Meal-time self-measured blood glucose increment averaged over the three main meals was significantly lower in the BIAsp 30 group than in the BHI 30 group (-0.68 (-1.20; -0.16) mmol/l; P < 0.02). Significant improvements were observed after breakfast, before lunch, after dinner and at bedtime (P < 0.02-0.05), with blood glucose around 1.0 mmol/l lower in the BIAsp 30 group. The number of major hypoglycaemic episodes with BIAsp 30 was half that with BHI 30. However, the overall risk of both minor and major hypoglycaemia did not differ significantly between treatments.

CONCLUSION

Post-prandial glycaemic control was significantly improved, without increasing the risk of hypoglycaemia, and overall control was similar when people with Type 1 and Type 2 diabetes were treated on a twice-daily regimen with immediate premeal injections of BIAsp 30 compared with BHI 30.

Clinical pharmacokinetics and pharmacodynamics of insulin aspart

Insulin aspart is a novel rapid-acting insulin analogue with improved subcutaneous absorption properties when compared with soluble human insulin. Pharmacokinetic studies show an absorption profile with a time to reach peak concentration (t(max)) about half that of human insulin, a peak plasma drug concentration (Cmax) approximately twice as high and shorter residence time. The potency and bioavailability of insulin aspart are similar to those of human insulin. The pharmacokinetics of insulin aspart have been studied in healthy Caucasian and Asian-Japanese volunteers, in patients with type 1 and 2 diabetes mellitus, and in children with diabetes, with both pre- and postprandial administration and during continuous subcutaneous insulin infusion (CSII). The pharmacokinetic profile was similar to that of another rapid-acting insulin analogue, insulin lispro, on the basis of published information for that agent. Pharmacodynamic studies show a smaller excursion of postprandial glucose with insulin aspart injected subcutaneously just before the meal compared with soluble human insulin injected 30 minutes before the meal in patients with type 1 diabetes mellitus, and an equivalent control in patients with type 2 diabetes displaying residual insulin production. In a treatment study, glucose excursions evaluated from 24-hour glucose profiles showed less variability with insulin aspart compared with human insulin. Adverse events, including hypoglycaemia-induced ventricular repolarisation and hypoglycaemic threshold and awareness, did not differ between insulin aspart and human insulin. The available data suggest that subcutaneous injections of insulin aspart just before meals better mimic the endogenous insulin profile in blood compared with human insulin, resulting in improved glucose control in a meal-related insulin regimen. This review summarises the clinical pharmacokinetics and pharmacodynamics of insulin aspart in relation to human insulin and insulin lispro.

Water intake and fluid shifts in horses: effects of hydration status during two exercise tests

In the present study, the main objective was to study factors affecting postexercise voluntary water intake in horses. Four Standardbred horses (mean +/- s.e. bwt 500 +/- 8 kg) were used to study water intake and effects of altering hydration status before an incremental exercise test (INCR) and a 40 min constant velocity exercise test (CONST) on a treadmill. Exercise was performed during normohydration (N), after dehydration for 24 h (DEH) and after hyperhydration with 12 l water 30 min before exercise (HH). DEH resulted in a bodyweight loss of 3% and there were signs of some fluid uptake prior to exercise in both HH trials. By the end of the INCR, the calculated change in plasma volume (PVcalc) was -13 +/- 1, -21 +/- 1 and -11 +/- 3% in the N, DEH and HH trials, respectively. During the highest exercise velocities a hypotonic shift of fluid was seen in all INCR trials. There was a greater accumulation of plasma lactate (pLA) in HH-than in N-INCR, probably caused by the extra weight to be carried. CONST induced a similar fluid loss (3%) in all trials, but the decrease in PVcalc at the end of exercise was significantly smaller in HH (-7 +/- 2%) than in N (-14 +/- 1%) and DEH (-19 +/- 2%). In DEH-INCR and DEH-CONST, plasma sodium concentration (pNa) was higher than in N until drinking water was offered 1 h postexercise. In the presence of both an increased pNa and a decrease in PVcalc when dehydrated, the horses drank immediately when offered water postexercise. In N-CONST, there was a significant decrease in calculated PVcalc (-10 +/- 2%) but no increase in pNa when water was given and in this trial the horses rehydrated less rapidly. Plasma aldosterone concentration (PAC) had increased to the same magnitude in all trials after about 10 min, irrespective of type of exercise or hydration status. It was concluded that when both an osmotic and hypovolemic thirst stimulus was present, the horses rehydrated more rapidly postexercise.

Effects of acute intravenous aldosterone administration on Na(+), K(+), and water excretion in the horse

The effect of a temporary increase in plasma aldosterone concentration on Na(+), K(+), and water balance was investigated in four horses. Aldosterone was injected intravenously for 6 h at 20-min intervals (total 5.4 microg/kg body wt). Samples were taken for 24 h before, during, and for 48 h after the treatment. Aldosterone treatment reduced the Na(+) loss via urine and feces by 99 and 72%, respectively, later followed by a marked increase in Na(+) excretion by both pathways. During the first 6 h after the treatment, fecal K(+) excretion was elevated, and the plasma K(+) concentration was lowered. Fluid was retained throughout the treatment period and for 12-15 h thereafter. In a second experiment, exercise was performed once after aldosterone treatment and once without prior treatment. Sweat samples were collected, and the composition was not altered after treatment. It was concluded that acute aldosterone injections reduce Na(+) losses in both feces and urine but not in sweat. In addition, the feces was shown to be the main excretion pathway of aldosterone.

Glycaemic control in type 1 diabetic patients using optimised insulin aspart or human insulin in a randomised multinational study

Insulin aspart (IAsp), is a rapid-acting analogue of human insulin (HI), for use in the meal related treatment of diabetes mellitus. The degree of glycaemic control achieved by IAsp in comparison with HI after algorithm-driven dose optimisation was tested over 3 months. The prospective, multicentre, randomised, open-label study with parallel groups was performed in 48 centres in 11 countries and included 423 basal-bolus treated patients with Type 1 diabetes. Main outcome measures were blood glucose control assessed by HbA1c, nine-point self-monitored blood glucose profiles, insulin dose, quality of life, hypoglycaemia and adverse events. An algorithm-driven increase occurred in the dose and number of daily injections of basal insulin, particularly in the IAsp group. After 12 weeks of treatment, HbA1c was significantly lower in IAsp compared to HI treated subjects by 0.17 (95% CI 0.30-0.04) (P<0.05). Comparison of the blood glucose profiles showed lower blood glucose levels with IAsp after breakfast (mean 8.4 vs 10.1 mmol/l; P<0.0001) and dinner (8.2 vs 9.3 mmol/l; P<0.01). There were no differences between treatments in the incidence of hypoglycaemic episodes or in the adverse event profiles. The WHO Diabetes Treatment Satisfaction Questionnaire score for perceived hyperglycaemia was lower with Iasp (P=0.005), and patients found the insulin aspart treatment more flexible (P=0.022). The current study underlines the need for optimising the basal insulin regimen in order to take full advantage of the pharmacodynamics of IAsp.

The use of a neutralizing monoclonal antibody to detect infections of equine herpesvirus type 2 (EHV-2)

A blocking enzyme-linked immunosorbent assay (ELISA) was developed to detect antibodies to equine herpesvirus 2 in serum samples of horses. By measuring the binding to a single epitope, this blocking ELISA gives a good picture of the antibody status in the animal. The test is based on a monoclonal antibody with neutralizing activity and had a sensitivity of 94% and a specificity of 100%. Antibodies due to newly acquired infection in foals were successfully detected with this blocking ELISA.

Insulin aspart vs. human insulin in the management of long-term blood glucose control in Type 1 diabetes mellitus: a randomized controlled trial

AIMS

To compare the efficacy of insulin aspart, a rapid-acting insulin analogue, with that of unmodified human insulin on long-term blood glucose control in Type 1 diabetes mellitus.

METHODS

Prospective, multi-centre, randomized, open-labelled, parallel-group trial lasting 6 months in 88 centres in eight European countries and including 1,070 adult subjects with Type 1 diabetes. Study patients were randomized 2:1 to insulin aspart or unmodified human insulin before main meals, with NPH-insulin as basal insulin. Main outcome measures were blood glucose control as assessed by HbA1c, eight-point self-monitored blood glucose profiles, insulin dose, quality of life, hypoglycaemia, and adverse events.

RESULTS

After 6 months, insulin aspart was superior to human insulin with respect to HbA1c with a baseline-adjusted difference in HbA1c of 0.12 (95% confidence interval 0.03-0.22) %Hb, P < 0.02. Eight-point blood glucose profiles showed lower post-prandial glucose levels (mean baseline-adjusted -0.6 to -1.2 mmol/l, P < 0.01) after all main meals, but higher pre-prandial glucose levels before breakfast and dinner (0.7-0.8 mmol/l, P < 0.01) with insulin aspart. Satisfaction with treatment was significantly better in patients treated with insulin aspart (WHO Diabetes Treatment Satisfaction Questionnaire (DTSQ) baseline-adjusted difference 2.3 (1.2-3.3) points, P < 0.001). The relative risk of experiencing a major hypoglycaemic episode with insulin aspart compared to human insulin was 0.83 (0.59-1.18, NS). Major night hypoglycaemic events requiring parenteral treatment were less with insulin aspart (1.3 vs. 3.4% of patients, P < 0.05), as were late post-prandial (4-6 h) events (1.8 vs. 5.0% of patients, P < 0.005).

CONCLUSIONS

These results show small but useful advantage for the rapid-acting insulin analogue insulin aspart as a tool to improve long-term blood glucose control, hypoglycaemia, and quality of life, in people with Type 1 diabetes mellitus.

Influence of bacitracin on microbial functions in the gastrointestinal tract of horses

This study investigated the influence of zinc bacitracin on the intestinal flora of horses. The functionally active intestinal flora was examined in 6 horses during treatment with zinc bacitracin. Utilising gas chromatography, spectrophotometry, gel electrophoresis and paper chromatography, samples were analysed on biochemical markers reflecting the action of parts of the intestinal flora. The following 5 flora-related functions were studied in faecal samples and intestinal samples from different sections of the hindgut: conversion of cholesterol to coprostanol and of bilirubin to urobilinogens, degradation of mucin and of beta-aspartylglycine and inactivation of tryptic activity. Conversion to coprostanol, conversion to urobilinogens and degradation of mucin were affected by treatment of zinc bacitracin and conversion to coprostanol was most sensitive. All functions were normalised in a short time, in contrast to man and rats. Differences in environmental exposures are probably the reason for a more rapid normalisation of the intestinal flora functions in horses.

Symptomatic and counterregulatory hormonal responses to acute hypoglycaemia induced by insulin aspart and soluble human insulin in Type 1 diabetes

BACKGROUND

The aim of this study was to assess hypoglycaemia awareness with the insulin analogue, insulin aspart. The counterregulatory hormonal and symptomatic responses to hypoglycaemia induced by insulin aspart were compared with soluble human insulin in a double-blind, randomised, two-period crossover trial in patients with Type 1 diabetes. The primary objective was to compare the blood glucose threshold for autonomic activation during hypoglycaemia induced by insulin aspart and soluble human insulin. Secondary objectives were to compare the counterregulatory, symptomatic and physiological responses to hypoglycaemia.

METHODS

20 patients were screened, 17 were randomised and 16 completed the study. Acute hypoglycaemia was induced by intravenous infusion of insulin aspart or soluble human insulin (100 U ml(-1) at a rate of 2 mU kg(-1) min(-1)).

RESULTS

No statistical difference between insulin aspart and soluble human insulin was shown for the primary blood glucose endpoint; mean arterialised blood glucose concentrations (+/-SD) at the onset of autonomic activation were 1. 88+/-0.39 mmol L(-1) for insulin aspart and 1.89+/-0.43 mmol L(-1) for soluble human insulin (not significant). No statistical differences were observed between the two insulins for the secondary endpoints: counterregulatory hormonal responses, autonomic responses, hypoglycaemia symptom scores, cognitive function and blood glucose responses. No serious adverse events were reported during the study.

CONCLUSIONS

Insulin aspart and soluble human insulin elicit the same counterregulatory and symptomatic responses to acute hypoglycaemia in patients with Type 1 diabetes.

Rapid appearance and onset of action of insulin aspart in paediatric subjects with type 1 diabetes

The pharmacokinetics of the novel, rapid-acting insulin aspart were compared with those of soluble human insulin following subcutaneous administration in nine children (aged 6-12 years) and nine adolescents (aged 13-17 years) with stable type 1 diabetes. The study had a randomised, double-blind, two-period crossover design. Each patient received a single subcutaneous dose of insulin aspart or human insulin (0.15 IU/kg body weight) 5 min before breakfast and the plasma insulin and glucose concentrations were measured at intervals during the following 5 h. The pharmacokinetic profile of insulin aspart differed significantly from that of human insulin with a higher mean maximum serum insulin (Cmax ins), 881 +/- 321 (SD) pmol/l versus 422 +/- 193 pmol/l for human insulin (P < 0.001); and with a shorter median serum insulin tmax ins, 40.0 min (interquartile range: 40-50 min) versus 75.0 min (interquartile range: 60-120 min) for human insulin, (P < 0.001). An age-related effect on Cmax ins and area under the curve (AUC0-5 h ins) was observed with higher values in adolescents than in children for both insulin aspart and human insulin. Postprandial glycaemic control was improved with insulin aspart; the baseline-adjusted delta Cmax glu being lower for insulin aspart compared with human insulin (increase of 7.6 +/- 5.1 versus 9.4 +/- 4.4 mmol/l respectively, P < 0.05). The incidence of adverse events was similar for the two insulin types.

CONCLUSION

The more rapid onset of action of insulin aspart versus human insulin, previously observed in adults, is confirmed in a paediatric population with type 1 diabetes.

Six intestinal microflora-associated characteristics in sport horses

The aim of this study was to investigate 6 microflora-associated characteristics (MACs) in faecal samples from horses and to compare the results with baselines previously established in other mammals. A MAC is defined as any anatomical structure, physiological, biochemical or immunological characteristic in a host, which has been acted on by microorganisms. When the active microbes are absent, as in germ-free animals and healthy newborn organisms, the corresponding characteristic is defined as germ-free animal characteristic (GAC). The MACs studied were degradation of mucin, conversion of cholesterol to coprostanol and bilirubin to urobilinogens, inactivation of tryptic activity, degradation of beta-aspartylglycine and excretion of short-chain fatty acids. Five MACs were studied in 19 sport horses and the mucin pattern investigated in 25 other sport horses. Our results show that conversion of cholesterol to coprostanol was present in all horses, irrespective of diet. All horses also demonstrated excretion of urobilinogens; however, the values varied depending on diet. Mucin and beta-aspartylglycine were totally degraded, as occurs similarly in other animal species. Excretion of short-chain fatty acids was lower than values previously found in man, rats and pigs, and the level of faecal tryptic activity was low. Our results show that the MAC/GAC concept is as good in monogastric herbivores as in omnivores for investigations of endogenous and exogenous factors influencing the intestinal ecosystem(s). Therefore, use of the MAC/GAC concept has a potential significance for future studies on functions related to the microflora.

Injectable dextranomer-based implant: histopathology, volume changes and DNA-analysis

OBJECTIVE

To study the tissue reaction in and around the implant, the changes in implant volume and the DNA profile of the invading cells when a new substance, dextranomers in sodium hyaluronan solution (DiHA), was injected into experimental animals.

MATERIALS AND METHODS

Nine pigs were followed up from 2 weeks to 3.5 months and 34 rats were followed up from 3 weeks to 16 months after injection of DiHA into the bladder in pigs and into the subcutaneous tissue in rats. Histopathological analysis was performed in 16 pig and 63 rat implants. In 31 of the rat implants the DNA profile was analysed. Changes in implant volume over time were estimated in 51 rat implants during the period up to 12 months after implantation.

RESULTS

Histologically, in the early phases the area within and around the implant was fairly rich in cells, predominantly fibroblasts, inflammatory cells and giant cells of the foreign body type. Later in the process an increase in extracellular matrix around the microspheres and ingrowth of blood vessels was seen. No tissue necrosis or significant eosinophilia was observed around the implants. DNA measurements by flow cytometry revealed no aneuploid cells. There was a decrease in implant volume by 23% over a period of 12 months.

CONCLUSIONS

DiHA does not induce any major tissue changes in and around the implants. No DNA changes were observed during the study period of 16 months. DiHA seem to be a safe and suitable injectable substance with good tissue-augmenting properties.

Effects of potassium intake on potassium, sodium and fluid balance in exercising horses

The aim of this study was to investigate the adaptation to an increased potassium (K+) intake in horses and to study whether the regulation of the post exercise K+, sodium (Na+) and fluid balances were altered by an increased K+ intake. Four Standardbred horses were fed 2 levels (4.1 and 5.4 mmol/kg bwt/day) of K+ for 17 days in a crossover design. The effects on K+, Na+ and fluid balance were studied both at rest and in response to 29 km exercise. K+, Na+ and fluid intakes and outputs were balanced within 24 h after a new diet had been introduced. Adaptation consisted primarily of an increased urinary K+ excretion, later followed by an increase in faecal excretion. The increased urinary K+ excretion was associated with an increased mass of urine (1.2-1.4 kg/day) compensated for by an increased water intake. The sweat Na+ concentration was increased on the highest K+ intake (from 123 +/- 5 mmol/l to 138 +/- 3 mmol/l) and the urinary Na+ excretion was lower post exercise on this diet. There were no differences in the magnitude of post exercise hypokalaemia between the diets, and plasma K+ concentration was still reduced 24 h post exercise even when the horses were fed the higher K+ diet. Adaptation to an increased K+ intake was rapid in these horses and consisted mainly of an increased urinary excretion. The response to exercise was unaltered by the increased K+ intake, except for an increased Na+ concentration in sweat.

Muscle adenine nucleotide degradation during submaximal treadmill exercise to fatigue

The aim was to investigate metabolic response in muscle during submaximal treadmill exercise to fatigue, with a special emphasis on adenine nucleotide degradation products such as inosine monophosphate (IMP) in muscle and hypoxanthine, xanthine and uric acid in plasma. Five Standardbred trotters performed treadmill exercise on 2 occasions, once at 7 m/s and once at 10 m/s. Venous blood samples were taken at rest, during exercise and at the end of exercise. Muscle biopsies were taken before and after exercise and muscle temperature was measured before and after exercise. Running time differed among horses and was 48-58 min at 7 m/s and 10-15.5 min at 10 m/s. Both lactate and uric acid concentrations in plasma showed a gradual increase during exercise at both 7 and 10 m/s. At the end of exercise, values for uric acid were higher and values for lactate lower at 7 m/s compared with at 10 m/s. No marked changes were seen in plasma concentrations of hypoxanthine or xanthine with exercise. Muscle glycogen decreased after exercise at both 7 and 10 m/s with a marked depletion seen in some fibres. Muscle lactate concentrations increased after exercise at both 7 m/s and at 10 m/s. No significant changes were seen in adenosine triphosphate (ATP), ADP and AMP concentrations, whereas IMP concentrations increased after exercise at both 7 m/s and at 10 m/s. The results of this study indicate that AMP deamination occurs with submaximal exercise and that development of fatigue may be related to adenine nucleotide degradation in muscle.

A comparison of the ultrastructure and metabolic response of the skeletal muscle of horses performing intense treadmill exercise at 20 and 35 degrees C

The aim of this study was to determine whether the metabolic response and ultrastructure of muscle differed when horses performed intense exercise at different ambient temperatures. Four Standardbred geldings performed treadmill exercise, including an intensive trot of 2600 m on two different occasions, either at a high ambient temperature of 35 degrees C or at a temperature of 20 degrees C. The horses had a warm-up period of 23.5 min of submaximal exercise, followed by 2 h of box rest before the intensive exercise. Muscle biopsy data of adenine nucleotides, creatine phosphate, lactate and glycogen concentrations measured before the warm-up period were similar to those measured before the period of intensive exercise. Muscle lactate concentrations did not differ between the two temperatures, but increased significantly after intense exercise to levels of 34.7 +/- 8.3 mmol/kg d.w. at 20 degrees C, and to 41.7 +/- 12.5 mmol/kg d.w. at 35 degrees C. Muscle glycogen and creatine phosphate concentrations did not differ between the two ambient temperatures, but decreased significantly by 122 +/- 82 mmol/kg d.w. and 25.2 +/- 17.4 mmol/kg d.w., respectively, after the intensive exercise. No changes were seen in adenosine triphosphate, adenosine diphosphate and adenosine monophosphate concentrations. The muscle biopsies were investigated by electron microscopy, and showed no marked changes in the ultrastructure of the muscle due to exercise at the two different ambient temperatures. In conclusion, no marked changes were seen in the muscle metabolic response or in the ultrastructure of the muscle when the horses performed intense exercise at 35 degrees C compared to 20 degrees C.

Comparative pharmacokinetics and pharmacodynamics of the novel rapid-acting insulin analogue, insulin aspart, in healthy volunteers

OBJECTIVE

The pharmacokinetics of a new insulin analogue, insulin aspart, were compared with unmodified human insulin in a double-blind crossover study of 25 fasting healthy men following a single subcutaneous dose.

METHODS

Either insulin aspart or human insulin, 0.1 U x kg-body-weight(-1), was injected subcutaneously and followed by determination of 8-h profiles of serum insulin and plasma glucose concentrations.

RESULTS

The absorption of insulin aspart was, on average, more than twice as fast and reached levels more than twice as high compared with human insulin [tmax(ins) of 52 (23) vs 145 (93) min, P < 0.0001; and Cmax(ins) of 41 (11) vs 18 (4) mU x l(-1), P < 0.0001; mean with (SD)]. However, total bioavailability did not differ between the insulins, and thus the mean residence time was significantly shorter for insulin aspart [MRT(ins) of 149 (26) vs 217 (30) min, P < 0.0001]. Plasma glucose (PG) fell more than twice as rapidly [tmin(PG) of 94 (45) vs 226 (120) min, P < 0.0001], to a greater extent [Cmin(PG) 2.1 (0.6) vs 1.4 (0.4) mmol x l(-1), P < 0.0001], and for a shorter duration with insulin aspart than with human insulin.

CONCLUSION

With improved subcutaneous absorption characteristics, the insulin aspart concentration-time profile resembles physiological meal-stimulated insulin release more closely than that of unmodified human insulin. This significantly alters the pharmacodynamic response in an advantageous manner in the meal-related treatment of diabetes mellitus.

Improved postprandial glycemic control with insulin aspart. A randomized double-blind cross-over trial in type 1 diabetes

OBJECTIVE

Insulin aspart is a novel rapid-acting insulin analog. This study was performed to compare the postprandial serum glucose control after administration of insulin aspart with that of unmodified human insulin.

RESEARCH DESIGN AND METHODS

The trial was a double-blind double-dummy injection three-way cross-over study in 22 subjects with type 1 diabetes. Insulin aspart was injected subcutaneously immediately before the meal, and human insulin was injected subcutaneously 30 min before the meal or immediately before the meal.

RESULTS

The postprandial glucose control as assessed by the excursion of serum glucose was superior with insulin aspart as compared with that with human insulin injected immediately before or 30 min before a meal (891 +/- 521 vs. 1,311 +/- 512 vs. 1,106 +/- 571 mmol.l-1.min-1, P < 0.0001 and P < 0.02). This was accompanied by a significantly lower glucose maximum concentration [Cmax(SG)] for insulin aspart than for human insulin injected immediately before the meal (13.5 +/- 3.5 vs. 16.4 +/- 3.4 mmol/l, P < 0.001). Insulin aspart was, on average, absorbed twice as fast as human insulin, with median time to insulin aspart Cmax(ins) on the order of 40 min, and the maximum concentration was approximately twice as high for insulin aspart. The relative bioavailability of the insulins indicated a similar extent of absorption. Insulin aspart was well tolerated.

CONCLUSIONS

This study demonstrates the ability of insulin aspart to improve postprandial glucose control when compared with human insulin.

Muscle characteristics and plasma lactate and ammonia response after racing in Standardbred trotters: relation to performance

Blood samples from the jugular vein and muscle biopsies (gluteus medius) in 25 Standardbred trotters were obtained 5-10 min after racing. The biopsies were analysed for fibre type composition and enzymatic profile and blood samples for plasma lactate and ammonia concentrations. Muscle characteristics, plasma lactate and ammonia concentrations after racing were compared with each horse's individual performance index (IPI). The IPI is calculated annually from the individual horse's racing performance (% placing 1, 2 or 3, total annual earnings, average earning per start, and best racing record), respectively, converted to and expressed as a percentage deviation from the average record of the same sex and age group. The IPI values were 100-116. Plasma lactate concentrations were 15.0-42.7 mmol/l (mean 31.3 mmol/l) and ammonia concentrations 65-210 micromol/l (mean 141 micromol/l) after racing. Fibre type composition varied among horses (range 9-27% for Type I, 32-54% for Type IIA, and 27-46% for Type IIB). Fibre type composition, enzyme activities, plasma lactate and ammonia responses to racing were not correlated to IPI. Ten of the horses also performed a submaximal test on the track, consisting of 5 incremental 1000 m heats at approximate speeds of 9.1, 9.5, 10.0, 10.5, and 11.1 m/s. Immediately after each heat a blood sample was drawn from the jugular vein for plasma lactate analysis. Plasma lactate response to exercise differed between horses, but no correlation was seen with IPI. Muscle characteristics, plasma lactate and ammonia concentrations after racing and lactate response to a submaximal track test did not correlate with current race performance expressed as IPI in a group of horses with average or better performance capacity at the time of testing. Analysis of lactate and ammonia in blood after racing is not a valuable tool to predict an individual performance index.

Studies on equine lipid metabolism. 2. Lipolytic activities of plasma and tissue lipases in large horses and ponies

The enzymatic fundamentals of lipid metabolism of equine have not been thoroughly investigated at this point in time. It is still unclear why ponies in contrast to horses may become hyperlipaemic when coming negative energy balance. In this study, the activities of the triglyceride-cleaving key enzymes of ponies are large bred horses were investigated in order to obtain insight into the aetiology of the syndrome. The objective of the study was to measure the activities of hormone-sensitive lipase (HSL), lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) in ponies and horses in ex vivo in vitro assays. Norepinephrine (NE) stimulated pony adipocytes to release FFA in a linear fashion (4.57 +/- 2.09 nmol FFA.10(5) cells-1.min-1). This was not observed in horses. Lipolysis was significantly higher in fat cells of ponies than in horses when adenosine deaminase (ADA) and NE were added (12.71 +/- 3.12 vs. 1.96 +/- 1.22 nmol FFA.10(5) cells-1.min-1). Relative inhibition of lipolysis by the action of insulin was comparable in adipocytes of horses and ponies. However, absolute FFA release in pony fat cells was as high as the maximal NE and ADA stimulated lipolysis in horse adipocytes. Postheparin plasma lipase activities in ponies and horses did not differ between the sub-species. This finding was supported by the results obtained from measurement of LPL activity in adipose and muscle tissue showing only a tendency of increased activities in pony explants when compared to horse tissue incubations. This study further supports the hypothesis that differences in regulation of TG release from fat stores rather than clearance of TG from plasma is causative for the development of hyperlipaemia in ponies. Abbreviations used: ADA, adenosine deaminase; BW, body weight; FFA, free fatty acid; HSL, hormone-sensitive lipase; HTGL, hepatic triglyceride lipase; LPL, lipoprotein lipase; NE, norepinephrine; SDS, sodium dodecyl sulfate; TG, triglyceride; VLDL, very low density lipoprotein.

Effects of differently composed feeds and physical stress on plasma gastrin concentration in horses

Plasma gastrin concentrations were determined in 6 Standardbreds (4 geldings and 2 mares) after 3 different meals consisting of unlimited amounts of hay (8-9 kg per horse), a restricted amount of hay (0.6 kg/100 kg body-weight) and grain (0.2 kg/100 kg body-weight) in combination or of grain alone (0.2 kg/100 kg body-weight). In another series of experiments the possible role of gastrin as a stress hormone was investigated. Plasma gastrin and cortisol concentrations were determined during fasting and compared with concentrations during hay feeding. In addition, gastrin and cortisol concentrations were determined before, during and after 2 kinds of physical exercise on a treadmill. Meal stimulation significantly increased the plasma gastrin concentration, irrespective of the meal composition. An immediate and large increase in plasma gastrin concentration was found when voluminous meals were given, whereas a small meal evoked a later onset of gastrin release, suggesting that gastric distention plays an important role in inducing gastrin release during a meal. Meals consisting of grain seem to evoke a slower onset and then a more prolonged gastrin response than a hay meal, possibly due to different emptying rates of the stomach. Nervous excitation may play a minor role in the activation of gastrin release in horses. No experimental support was obtained for the idea that gastrin acts as a stress hormone in the horse.

Improved glycemic control with insulin aspart: a multicenter randomized double-blind crossover trial in type 1 diabetic patients. UK Insulin Aspart Study Group

OBJECTIVE

To compare glycemic control obtained with the new rapid-acting insulin analog insulin aspart with that obtained with unmodified human insulin using algorithm-driven dosage adjustment.

RESEARCH DESIGN AND METHODS

This was a multicenter randomized double-blind crossover study of 90 male subjects with type 1 diabetes. Insulin aspart or soluble human insulin was administered before meals, and NPH insulin was administered at bedtime as basal therapy. Each 4-week study period ended with a 24-h inpatient serum insulin and plasma glucose profile.

RESULTS

The 24-h plasma glucose control obtained with insulin aspart, as assessed by excursions of blood glucose outside a predefined normal range (4.0-7.0 mmo/l), was superior (22% reduction in excursion, P < 0.01). Fructosamine levels remained unchanged with insulin aspart, with daytime glycemic control superior but nighttime glycemic control inferior. Eight-point home blood glucose profiles confirmed that insulin aspart significantly improved postprandial blood glucose control after lunch and dinner (P < 0.05) without deterioration of preprandial blood glucose control. Hypoglycemic episodes requiring third-party intervention were significantly fewer with insulin aspart than with human insulin (20 vs. 44 events, P < 0.002). Insulin aspart was well tolerated.

CONCLUSIONS

In comparison with human insulin, insulin aspart can improve postprandial glycemic control as assessed by a reduction in hyper- and hypoglycemic excursions in people with type 1 diabetes. For its full potential to be realized, it will need to provide better control of nighttime hyperglycemia.

GBV-C/HGV infection in hepatitis C virus-infected deferred Swedish blood donors

Sera from 62 hepatitis C virus (HCV)-infected Swedish blood donors were tested by a nested polymerase chain reaction using primers targeting the 5'-noncoding region of the GB virus-C/hepatitis G (GBV-C/HGV) genome and an enzyme-linked immunosorbent assay that detects antibodies to the envelope protein E2 of GBV-C/HGV (anti-E2). Fourteen (22%) and 21 (34%) of the 62 blood donors were found to be GBV-C/HGV RNA and anti-E2 positive, respectively. None of the blood donors was positive for both GBV-C/HGV RNA and anti-E2. Thus, 35 of 62 (56%) HCV-infected donors had been exposed to GBV-C/HGV infection. At sequencing of the 14 GBV-C/HGV isolates, 12 were identified as subtype 2a and 2 as subtype 2b. One of 7 (14%) donors with mild liver disease such as steatosis and nonspecific reactive hepatitis had been exposed to GBV-C/HGV vs. 34 of 55 (62%) with chronic hepatitis with or without cirrhosis (P = 0.04). All other differences in histology were small between HCV and dual HCV GBV-C/HGV-infected donors. In conclusion, more than half of HCV-infected Swedish blood donors in this study were positive for either GBV-C/HGV RNA or anti-E2. GBV-C/HGV viremia and seropositivity were mutually exclusive.

Effects of differently composed feeds and physical stress on plasma gastrin concentration in horses

Plasma gastrin concentrations were determined in 6 Standardbreds (4 geldings and 2 mares) after 3 different meals consisting of unlimited amounts of hay (8-9 kg per horse), a restricted amount of hay (0.6 kg/100 kg body-weight) and grain (0.2 kg/100 kg body-weight) in combination or of grain alone (0.2 kg/100 kg body-weight). In another series of experiments the possible role of gastrin as a stress hormone was investigated. Plasma gastrin and cortisol concentrations were determined during fasting and compared with concentrations during hay feeding. In addition, gastrin and cortisol concentrations were determined before, during and after 2 kinds of physical exercise on a treadmill. Meal stimulation significantly increased the plasma gastrin concentration, irrespective of the meal composition. An immediate and large increase in plasma gastrin concentration was found when voluminous meals were given, whereas a small meal evoked a later onset of gastrin release, suggesting that gastric distention plays an important role in inducing gastrin release during a meal. Meals consisting of grain seem to evoke a slower onset and then a more prolonged gastrin response than a hay meal, possibly due to different emptying rates of the stomach. Nervous excitation may play a minor role in the activation of gastrin release in horses. No experimental support was obtained for the idea that gastrin acts as a stress hormone in the horse.

The association of erythromycin ethylsuccinate with acute colitis in horses in Sweden

In Sweden there are several reports of mares developing acute colitis while their foals were being treated orally for Rhodococcus equi pneumonia with the combination of erythromycin and rifampicin. In this study 6 adult horses were given low oral dosages of these antibiotics, singly or in combination. Within 3 days post administration of erythromycin, in one case in combination with rifampicin, 2 horses developed severe colitis (one fatal). Clostridium difficile was isolated from one of the horses, whereas no specific pathogens were isolated from the other. Both horses had typical changes in blood parameters seen in acute colitis. Clostridium difficile was also isolated from the faeces of a third horse given an even lower dosage of erythromycin in combination with rifampicin. This horse developed very mild clinical symptoms and recovered spontaneously. In the fourth horse given erythromycin only, very high numbers of Clostridium perfringens were isolated. The horses given rifampicin only did not develop any clinical symptoms and there were no major changes in their faecal flora. In conclusion, it has been demonstrated that low dosages of erythromycin ethylsuccinate can induce severe colitis in horses associated with major changes of the intestinal microflora. Clostridium difficile has been demonstrated as a potential aetiological agent in antibiotic-induced acute colitis.

Clostridium difficile associated with acute colitis in mature horses treated with antibiotics

Clostridium (C.) difficile, or its cytoxin, was demonstrated in faecal samples from 10 of 25 (40%) mature horses investigated with acute colitis treated primarily with antibiotics for disorders other than diarrhoea. C. difficile was not found in faecal samples from 140 horses without signs of enteric disorders, from 21 nondiarrhoeic horses treated with antibiotics, nor from 22 horses with colitis untreated with antibiotics. Except for C. difficile neither Salmonella nor any other investigated intestinal pathogen was isolated in any of the diarrhoeic horses. The findings strongly support some earlier reports that C. difficile is associated with acute colitis in mature horses treated with antibiotics. Of the 10 horses, 4 proved positive for C. difficile both in culture and in the cytotoxin test, 4 in culture only and 2 only in the cytotoxin test. Eight of 10 horses positive for C. difficile were or had recently been hospitalised, indicating that C. difficile may be a nosocomial infection in horses. All horses positive for C. difficile were treated with beta-lactam antibiotics.

Comparison of standardbred trotters exercising on a treadmill and a race track with identical draught resistances

The responses in heart rate, plasma lactate and rectal temperature of standardbred trotters to draught loaded interval exercise on a treadmill and a race track were studied. The horses were exercised with incrementally increasing trotting speeds for two-minute intervals with draught loads of 10, 20 and 30 kilopond (kp) in three different tests. Each trotting interval was followed by two-minute periods at a walk without a draught load. Measurements of heart rate and plasma lactate were made at the end of each interval and the rectal temperature was taken at the end of the exercise. The heart rate and plasma lactate levels were significantly lower on the treadmill than on the track in the tests with 10 kp, but no significant differences were found between the treadmill and track exercise tests with the heavier draught resistances. No differences were observed in rectal temperature between treadmill and track conditions. From these findings it was concluded that the workload was significantly greater on the race track compared to the treadmill when the draught resistance was low (10 kp). Although the workload increased on both the race track and the treadmill as draught resistance increased, at the heavier draught resistances track exercise was no longer more demanding than exercise on the treadmill.

Genetic markers in standardbred trotters susceptible to the rhabdomyolysis syndrome

The equine rhabdomyolysis syndrome (RHA) is believed to be multifactorial in origin; and could be caused by an interaction between genetic and environmental factors. In order to analyse its genetic background an association study was undertaken. Two sample groups of Standardbreds (Stb) which had suffered from RHA were compared to the total population of Swedish Standardbred trotters using recorded polymorphic genetic markers. The results showed that gene frequencies for several markers in the RHA groups differed significantly from those estimated for the total population. A rhabdomyolysis risk group could be characterised using 4 or 5 genetic marker loci.

Cardio-respiratory and plasma lactate responses to exercise with low draught resistances in standardbred trotters

Five Standardbred trotters performed treadmill exercise with incrementally increasing trotting velocities for 2 min intervals in three different tests until fatigue. Each test was performed with draught loads of either 10, 20 or 30 kilopond (kp). Each trotting interval was followed by 2 min periods at a walk without draught load. Recordings were made of heart rate (HR), respiratory rate (RR), plasma lactate (PLA) and stride frequency (SF) at the end of each trotting interval. The HR increased to average values of 191 +/- 10,203 +/- 10 and 214 +/- 7 bpm and PLA increased to 3.8 +/- 0.7, 7.3 +/- 3.8 and 10.8 +/- 6.4 mmol/l at 9 m/s in the three tests, respectively. The HR response to exercise was significantly higher with increasing draught loads, and PLA was significantly higher with 30 kp compared to 10 kp draught resistance. The lowest respiratory rate was seen in the test with 30 kp loading. Peak oxygen uptake (VO2peak) was measured in a separate test on a sloped treadmill with increasing velocities without draught load and averaged 70.4 +/- 9.11/min. Muscle biopsies were taken from the gluteus muscle. Individual variations were seen in VO2peak, muscle fibre composition and HR and PLA responses to exercise. In conclusion, at a certain velocity a small increase in draught resistance from 10 to 30 kp significantly increases both the HR and PLA responses. At comparable work intensities the horses differed in circulatory and metabolic responses to exercise.