The effect of exercise on intramyocellular acetylcarnitine (AcCtn) concentration in adult growth hormone deficiency (GHD)

To cover increasing energy demands during exercise, tricarboxylic cycle (TCA) flux in skeletal muscle is markedly increased, resulting in the increased formation of intramyocellular acetylcarnitine (AcCtn). We hypothesized that reduced substrate availability within the exercising muscle, reflected by a diminished increase of intramyocellular AcCtn concentration during exercise, might be an underlying mechanism for the impaired exercise performance observed in adult patients with growth hormone deficiency (GHD). We aimed at assessing the effect of 2 hours of moderately intense exercise on intramyocellular AcCtn concentrations, measured by proton magnetic resonance spectroscopy (¹H-MRS), in seven adults with GHD compared to seven matched control subjects (CS). Compared to baseline levels AcCtn concentrations significantly increased after 2 hours of exercise, and significantly decreased over the following 24 hours (ANOVA p for effect of time = 0.0023 for all study participants; p = 0.067 for GHD only, p = 0.045 for CS only). AcCtn concentrations at baseline, as well as changes in AcCtn concentrations over time were similar between GHD patients and CS (ANOVA p for group effect = 0.45). There was no interaction between group and time (p = 0.53). Our study suggests that during moderately intense exercise the availability of energy substrate within the exercising muscle is not significantly different in GHD patients compared to CS.

Genetic architecture of tipburn resistance in lettuce

KEY MESSAGE

Two major QTLs for tipburn were identified in LGs 1 and 5 contributing to resistance in cv. Salinas. The findings suggest pleiotropic effects between leaf crinkliness/savoy and tipburn. Tipburn is a physiological disorder in lettuce that is thought to be caused by a localized deficiency of calcium in leaf tissues. To elucidate the genetic architecture of resistance to tipburn in lettuce, seven recombinant inbred line populations were analyzed in multiple environments and years to identify quantitative trait loci (QTLs) for tipburn. Core height, head firmness, head closure, leaf crinkliness, plant fresh weight, and leaf savoy were also analyzed to investigate whether QTLs for these morphological traits collocated with QTLs for tipburn, which would be indicative of pleiotropic effects. Twenty-three major, intermediate, and minor unique QTLs for tipburn were identified in one or more populations scattered throughout the genome. Two major QTLs for tipburn incidence were identified in linkage groups (LGs) 1 and 5, which determined up to 45 and 66% of the phenotypic variance. The major QTL in LG 1 collocated with the head firmness QTL. The major QTL in LG 5 collocated with the QTL for core height, leaf crinkliness, and head firmness. Further research is needed to determine whether these associations are due to pleiotropic effects of the same gene or if the genes determining these traits are tightly linked. The beneficial alleles at the QTLs in LGs 1 and 5 are present in Lactuca sativa cv. Salinas, the genotype sequenced for the reference genome assembly. Therefore, these QTLs are good targets to identify genes causing tipburn as well as regions for marker-assisted selection to improve resistance to tipburn in lettuce.

Impaired repletion of intramyocellular lipids in patients with growth hormone deficiency after a bout of aerobic exercise

BACKGROUND

Ectopic lipids such as intramyocellular lipids (IMCL) are depleted by exercise and repleted by diet, whereas intrahepatocellular lipids (IHCL) are increased immediately after exercise. So far, it is unclear how ectopic lipids behave 24 h after exercise and whether the lack of growth hormone (GH) significantly affects ectopic lipids 24 h after exercise.

METHODS

Seven male patients with growth hormone deficiency (GHD) and seven sedentary male control subjects (CS) were included. VO_2max was assessed by spiroergometry; visceral and subcutaneous fat by whole body MRI. ¹H-MR-spectroscopy was performed in M. vastus intermedius and in the liver before and after 2 h of exercise at 50% VO_2max and 24 h thereafter, while diet and physical activity were standardized.

RESULTS

Sedentary male subjects (7 GHD, 7 CS) were recruited. Age, BMI, waist circumference, visceral and subcutaneous fat mass was not significantly different between GHD and CS. VO_2max was significantly lower in GHD vs. CS. IMCL were diminished through aerobic exercise in both groups: (-11.5 ± 21.9% in CS; -8.9% ±19.1% in GHD) and restored after 24 h in CS (-5.5 ± 26.6% compared to baseline) but not in GHD (-17.9 ± 15.3%). IHCL increased immediately after exercise and decreased to baseline within 24 h.

CONCLUSION

These findings suggest that GHD may affect repletion of IMCL 24 h after aerobic exercise.

Molecular photosensitisers for two-photon photodynamic therapy

Two-photon excitation has attracted the attention of biologists, especially after the development of two-photon excited microscopy in the nineties. Since then, new applications have rapidly emerged such as the release of biologically active molecules and photodynamic therapy (PDT) using two-photon excitation. PDT, which requires a light-activated drug (photosensitiser), is a clinically approved and minimally invasive treatment for cancer and for non-malignant diseases. This feature article focuses on the engineering of molecular two-photon photosensitisers for PDT, which should bring important benefits to the treatment, increase the treatment penetration depth with near-infrared light excitation, improve the spatial selectivity and reduce the photodamage to healthy tissues. After an overview of the two-photon absorption phenomenon and the methods to evaluate two-photon induced phototoxicity on cell cultures, the different classes of photosensitisers described in the literature are discussed. The two-photon PDT performed with historical one-photon sensitisers are briefly presented, followed by specifically engineered cyclic tetrapyrrole photosensitisers, purely organic photosensitisers and transition metal complexes. Finally, targeted two-photon photosensitisers and theranostic agents that should enhance the selectivity and efficiency of the treatment are discussed.

Evaluation of the frequency of adrenal crises and preventive measures in patients with primary and secondary adrenal insufficiency in Switzerland

AIMS OF THE STUDY

Adrenal insufficiency is a dangerous clinical condition, leading to significant morbidity or mortality in situations with inadequate glucocorticoid replacement treatment. We aimed to assess preventive measures in adrenal insufficiency and the incidence and risk factors of adrenal crisis, as well as to test the patients' knowledge about their disease.

METHODS

All patients in May and June 2016 and December 2016 and January 2017 with primary (17.9%) or secondary (82.1%) adrenal insufficiency were prospectively included in this observational study. They completed questionnaires about their personal and medical background, including the occurrence of adrenal crises, and possession of an emergency card and medication. They were asked about self-perceived subjective knowledge of their disease and filled out two multiple-choice tests about the modalities of the glucocorticoid replacement therapy (test A) and dose adaptation in hypothetical clinical situations (test B) in order to objectively test their knowledge.

RESULTS

A total of 56 datasets were available for descriptive and statistical analysis. Overall, 94.6% of the patients were equipped with an emergency card, 64.3% had their daily hydrocortisone with them and 57.1% carried spare hydrocortisone pills. Twelve patients had experienced at least one adrenal crisis. There were 4.4 adrenal crises per 100 disease-years. Precipitating causes for adrenal crises were mainly gastroenteritis, influenza and noncompliance. Globally, the patients' self-perceived, subjective knowledge level was good to very good. In the two objective knowledge tests, however, only 28.9% (test A) and 60.1% (test B) of the questions were answered correctly. Secondary adrenal insufficiency reduced the chance of being in the group with better knowledge in test A.

CONCLUSIONS

The incidence of adrenal crisis in Switzerland is lower than described in recent European studies. Although nearly all of the patients carry their emergency cards with them, emergency treatment is available in only about half of the patients. There is a mismatch between subjective and objective knowledge of the disease and the education of patients with adrenal insufficiency needs to be improved.

Changes of Thyroid Hormones and Their Binding Proteins during Plasma Exchange for Polyneuropathy in a Patient with Substituted Hypothyroidism due to Hashimoto's Thyroiditis

BACKGROUND

Pharmacodynamic studies and data concerning adaptation of thyroid substitution in patients with substituted hypothyroidism during plasma exchange (PE) is not available.

CASE REPORT

We measured TSH, fT3 and fT4, total T4, thyroxin binding globulin (TBG), and albumin before and after 5 PE procedures in a 37-year-old women who underwent PE for a therapy-resistant polyneuropathy. Thyroxin was increased empirically by 8% resulting in a dose of 1.95 µg/kg per day.

RESULTS

Despite larger reductions of total T4 and TBG over a series of 5 PEs (40-50% from baseline), only small reductions of 8% in fT3 and fT4 concentrations were documented with a concomittant increase in TSH level. Changes of fT4, fT3, and TSH remained within normal range.

CONCLUSIONS

i) Despite a significant decrease in total thyroid hormone pool following PE, fT4, fT3, and TSH concentrations changed only slightly. ii) Based on this observation, a general increase in thyroid replacement therapy before PE cannot be recommended, but considered in case of a high normal TSH level.

π-Extended diketopyrrolopyrrole–porphyrin arrays: one- and two-photon photophysical investigations and theoretical studies

Diketopyrrolopyrrole–porphyrin conjugates show remarkable NIR emission properties, high two-photon absorption cross-sections and significant singlet oxygen production efficiency.

[Insulin therapy in type 2 diabetes: a review of "when" over "how" up to "why"]

Type 2 Diabetes is characterized by its progressive character. An intensification of the therapy is necessary in most cases over the years and insulin is typically used as an add-on agent when oral antidiabetic regimes are judged to be no longer sufficient. However, insulin can also be used in the initial phase of the disease directly after diagnosis of diabetes. Intermittent worsening of glycemic control (e.g. due to infectious diseases or corticosteroids) may be additional indications for an insulin treatment at an earlier stage. Noticeably, insulin can often be stopped if the triggering event or treatment is reversible, thereby countering the widely spread fear of dependency on insulin. We recommend a rather cautious starting dose of insulin and individual adaptations thereafter. Well-informed patients can also perform such adaptations themselves.

[A fever of finally known origin]

We present the case of a 77 year old man with fever of unknown origin. Despite a thorough assessment in hospital the diagnosis could only be made after discharge when positive results for C. burnetii serology revealed acute Q-fever. However, retrospectively history and clinical findings matched well with acute Q-fever.

Symptomatic treatment of ascites with a peritoneo-vesical automated fluid shunt system in a dog

A six-year-old Rottweiler with chronic ascites and moderate panhypoproteinaemia that had been treated with large volume paracentesis over several months duration was diagnosed with a large bi-atrial mass and hepatic fibrosis. For palliative treatment, a peritoneo-vesical automated fluid shunt system with an integrated chargeable battery and an integrated computer to control pump function and to transmit data transcutaneously was implanted by coeliotomy. The pump was left in place for 10 weeks, eliminating the need for further paracentesis during this time. At the end of this period, no ascites was discernible and serum protein concentrations had returned to their respective reference intervals. As a complication, decubitus with skin perforation had developed above the pump. Besides palliative treatment of chronic refractory ascites, this pump may have application in other conditions characterised by chronic cavity effusion or in peritoneal dialysis.

Noninvasive assessment of exercise-related intramyocellular acetylcarnitine in euglycemia and hyperglycemia in patients with type 1 diabetes using ¹H magnetic resonance spectroscopy: a randomized single-blind crossover study

OBJECTIVE

Intramyocellular acetylcarnitine (IMAC) is involved in exercise-related fuel metabolism. It is not known whether levels of systemic glucose influence IMAC levels in type 1 diabetes.

RESEARCH DESIGN AND METHODS

Seven male individuals with type 1 diabetes performed 120 min of aerobic exercise at 55-60% of Vo(2max) randomly on two occasions (glucose clamped to 5 or 11 mmol/l, identical insulinemia). Before and after exercise, IMAC was detected by ¹H magnetic resonance spectroscopy in musculus vastus intermedius.

RESULTS

Postexercise levels of IMAC were significantly higher than pre-exercise values in euglycemia (4.30 ± 0.54 arbitrary units [a.u.], P < 0.001) and in hyperglycemia (2.44 ± 0.53 a.u., P = 0.01) and differed significantly according to glycemia (P < 0.01). The increase in exercise-related levels of IMAC was significantly higher in euglycemia (3.97 ± 0.45 a.u.) than in hyperglycemia (1.71 ± 0.50 a.u.; P < 0.01).

CONCLUSIONS

The increase in IMAC associated with moderate aerobic exercise in individuals with type 1 diabetes was significantly higher in euglycemia than in hyperglycemia.

Response of interleukin-6 during euglycaemic and hyperglycaemic exercise in patients with type 1 diabetes mellitus

The aim of this randomized, single-blinded cross-over study was to investigate the response of interleukin-6 (IL-6) during moderate aerobic exercise in stable euglycaemia and hyperglycaemia in seven male patients with type 1 diabetes mellitus. IL-6 increased significantly over the entire study period in euglycaemia, but not in hyperglycaemia.

Exercise-induced growth hormone response in euglycaemia and hyperglycaemia in patients with Type 1 diabetes mellitus

AIMS

To compare exercise-induced growth hormone (GH) response in patients with Type 1 diabetes during stable euglycaemic and hyperglycaemic conditions.

METHODS

We conducted a randomized, controlled, single-blinded cross-over trial in seven male patients with well-controlled Type 1 diabetes. The patients cycled twice for 120 min at a level of 55-60% maximal oxygen uptake. Euglycaemia was at 5.0 mmol/l, hyperglycaemia at 11.0 mmol/l.

RESULTS

Area under the curve of GH (AUC(GH)) during exercise was significantly higher during euglycaemia [1430 ng ml(-1) min, 95% confidence interval (CI) 703-2910] compared with hyperglycaemia (1061 ng ml(-1) min, 95% CI 538-2091, P = 0.02).

CONCLUSIONS

In patients with Type 1 diabetes, GH concentrations during moderate aerobic exercise during stable hyperglycaemic conditions are significantly lower compared with euglycaemia. These findings are compatible with preserved glucose-mediated GH regulation during exercise in individuals with well-controlled Type 1 diabetes.

Use of auscultation and Doppler echocardiography in Boxer puppies to predict development of subaortic or pulmonary stenosis

BACKGROUND

Boxers are predisposed to subaortic and pulmonic stenosis (SAS, PS). Screening of puppies may be useful in estimating the risk of their developing a defect that potentially compromises life expectancy or exercise tolerance.

HYPOTHESIS

Presence of SAS or PS in adult Boxers can be predicted by auscultation and Doppler echocardiography at 9-10 weeks of age.

ANIMALS

Eighty-five Boxer puppies examined at 9-10 weeks of age and at 12 months of age.

METHODS

Prospective, longitudinal observational study. Auscultation by stethoscope and continuous wave-Doppler echocardiography for peak velocities (V(max)) in the aorta (Ao) and pulmonary artery (PA).

RESULTS

Intensity of heart murmurs in puppies correlated with V(max)Ao and V(max)PA in adults. V(max)Ao and V(max)PA in puppies correlated with V(max)Ao and V(max)PA in adults, respectively. From puppy to adult, V(max)Ao increased and V(max)PA remained unchanged. The negative predictive value for absent or only a soft (< or =II/VI) murmur in puppies being associated with V(max)Ao and PA < or = 2.4 m/s as an adult was 90% and < or =3.5 m/s 100%. The negative predictive value of a V(max)< or = 2.4 m/s as a puppy still being < or =2.4 m/s as an adult was 94% for Ao and 96% for PA, and of a V(max)< or = 3.5 m/s, 99% for Ao and 100% for PA.

CONCLUSIONS AND CLINICAL IMPORTANCE

Even though V(max)Ao increases during growth in Boxer puppies, indicating relative narrowing of the aorta, puppies with V(max)Ao < or = 2.4 m/s do not usually progress to clinically have relevant SAS at 12 months of age.

Fuel metabolism during exercise in euglycaemia and hyperglycaemia in patients with type 1 diabetes mellitus--a prospective single-blinded randomised crossover trial

AIMS/HYPOTHESIS

We assessed systemic and local muscle fuel metabolism during aerobic exercise in patients with type 1 diabetes at euglycaemia and hyperglycaemia with identical insulin levels.

METHODS

This was a single-blinded randomised crossover study at a university diabetes unit in Switzerland. We studied seven physically active men with type 1 diabetes (mean +/- SEM age 33.5 +/- 2.4 years, diabetes duration 20.1 +/- 3.6 years, HbA1c 6.7 +/- 0.2% and peak oxygen uptake [VO2peak] 50.3 +/- 4.5 ml min(-1) kg(-1)). Men were studied twice while cycling for 120 min at 55 to 60% of VO2peak, with a blood glucose level randomly set either at 5 or 11 mmol/l and identical insulinaemia. The participants were blinded to the glycaemic level; allocation concealment was by opaque, sealed envelopes. Magnetic resonance spectroscopy was used to quantify intramyocellular glycogen and lipids before and after exercise. Indirect calorimetry and measurement of stable isotopes and counter-regulatory hormones complemented the assessment of local and systemic fuel metabolism.

RESULTS

The contribution of lipid oxidation to overall energy metabolism was higher in euglycaemia than in hyperglycaemia (49.4 +/- 4.8 vs 30.6 +/- 4.2%; p < 0.05). Carbohydrate oxidation accounted for 48.2 +/- 4.7 and 66.6 +/- 4.2% of total energy expenditure in euglycaemia and hyperglycaemia, respectively (p < 0.05). The level of intramyocellular glycogen before exercise was higher in hyperglycaemia than in euglycaemia (3.4 +/- 0.3 vs 2.7 +/- 0.2 arbitrary units [AU]; p < 0.05). Absolute glycogen consumption tended to be higher in hyperglycaemia than in euglycaemia (1.3 +/- 0.3 vs 0.9 +/- 0.1 AU). Cortisol and growth hormone increased more strongly in euglycaemia than in hyperglycaemia (levels at the end of exercise 634 +/- 52 vs 501 +/- 32 nmol/l and 15.5 +/- 4.5 vs 7.4 +/- 2.0 ng/ml, respectively; p < 0.05).

CONCLUSIONS/INTERPRETATION

Substrate oxidation in type 1 diabetic patients performing aerobic exercise in euglycaemia is similar to that in healthy individuals revealing a shift towards lipid oxidation during exercise. In hyperglycaemia fuel metabolism in these patients is dominated by carbohydrate oxidation. Intramyocellular glycogen was not spared in hyperglycaemia.

Dehydroepiandrosterone sulfate in the assessment of the hypothalamic-pituitary-adrenal axis

CONTEXT

The role of dehydroepiandrosterone-sulfate (DHEA-S) in assessing the integrity of the hypothalamic-pituitary-adrenal (HPA) axis in patients with suspected insufficiency is uncertain.

OBJECTIVE

The objective of the study was to prospectively evaluate the diagnostic value of DHEA-S on HPA function in consecutive patients with suspected HPA insufficiency with and without pituitary lesions at a tertiary referral center.

DESIGN AND PATIENTS

In 70 consecutive patients, insulin tolerance test was accompanied by measurement of basal DHEA-S. Assessment of HPA axis was based on peak cortisol response in insulin tolerance test (normal > or = 550 nmol/liter). To account for the age and gender dependency of DHEA-S, a z-score was calculated using age- and gender-specific reference values of the assay.

RESULTS

Individuals with HPA insufficiency had significantly lower z-scores than those with normal HPA function (-1.66 vs. -0.62, P < 0.0001). In individuals up to 30 yr of age, a z-score of -2.0 had 100% sensitivity and specificity regarding HPA function [area under receiver operating characteristics (ROC) curve 1.00], whereas z-scores proved less useful in older individuals. In individuals with pituitary macroadenoma, a z-score below -2.0 had 100% specificity to predict HPA insufficiency (area under ROC curve 0.82). In the absence of a pituitary adenoma, the diagnostic value of the z-score was reduced (area under ROC curve 0.71).

CONCLUSIONS

Individuals with HPA insufficiency have lower z-scores for DHEA-S than those with normal HPA function. There is evidence that a z-score could be of diagnostic value in assessing HPA integrity, especially in younger patients and patients with pituitary macroadenoma, but further studies are needed to consolidate these findings.

[Simultaneous defect of visual fields and loss of libido--a coincidence?]

We present the case of a 60 year old male patient with incidentally detected visual abnormalities. Detailed personal history revealed a hypogonadism that had been present for several years. Further investigations established the diagnosis of an infiltrative macroadenoma. Medical treatment with cabergoline led to a rapid regression of ophthalmologic symptoms and, subsequently, of tumor size. In male subjects symptoms of hypogonadism are often reported only late in the course of the disease, thereby leading to a generally larger tumor size at the point of diagnosis. In contrast to other pituitary tumors that are mainly treated by surgery, medical treatment with dopamine agonists is the principal therapeutic option in prolactinomas.

Exercise capacity in subjects with type 1 diabetes mellitus in eu- and hyperglycaemia

BACKGROUND

Circumstantial evidence suggests that an increase in plasma glucose availability improves exercise capacity in subjects with type 1 diabetes mellitus. The aim of this study was to assess exercise capacity in eu- and hyperglycaemic conditions in subjects with type 1 diabetes.

METHODS

Eight moderately exercise-trained male subjects with type 1 diabetes on continuous subcutaneous insulin infusion were studied. Using identical insulin infusion rates, the patients were randomly allocated to perform two stepwise ergometer tests in eu- and hyperglycaemic clamp conditions. The primary endpoint was the peak power output; the secondary endpoints comprised the rate of perceived exertion, lactate levels, heart rate, and respiratory exchange ratio.

RESULTS

Eu- and hyperglycaemic clamp conditions were observed at a plasma glucose concentration of 5.3 +/- 0.6 mmol/L and 12.4 +/- 2.1 mmol/L, respectively (mean +/- SD), and remained stable throughout the physical exercise. Insulin levels were similar in both conditions. Hyperglycaemia did not result in a significant increase in the peak power output compared to euglycaemia (mean paired difference of 4.96 W, 95% CI - 11.3 to 21.2, p = 0.49). Hyperglycaemia did not have a significant impact on the secondary endpoints compared to euglycaemia. Sensitivity analyses confirmed these results.

CONCLUSIONS

In subjects with type 1 diabetes, exercise capacity is not influenced by hyperglycaemia. Comparable levels of lactate and similar respiratory exchange ratio suggest that an increase in extracellular glucose availability did not translate into increased intracellular glucose oxidation.