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Biomedical subjects

K G Petersen

Publications and source records attributed to K G Petersen.

At least 19 recordsLinked to original sources
PubMed2002

Training intensity influences leptin and thyroid hormones in highly trained rowers.

Leptin (L) is associated with body-weight-regulating and adipostatic functions. Its receptors also may be found centrally. Thyroid hormones regulate metabolic processes mainly by binding at peripheral receptors. Aim of this study was to show if there is a link between those central and peripheral regulation systems and to investigate the influence of different training intensities on L and the hypothalamic-thyroid-axis (HTA) in highly trained rowers. Six rowers (18.9 +/- 2.6 y; BMI 22.8 +/- 2.1 kg/m (2)) undertook high intensity resistance training (RT) for three weeks followed by three weeks of endurance training (ET). After each training cycle the subjects had one week for recovery (R1, R2). Blood samples were taken before and at the end of RT, R1, ET and R2. L, thyroid stimulating hormone (TSH), free T3 (fT3) and free T4 (fT4) were measured. After RT, a significant reduction in L, TSH and fT3 was found (p < 0.05). fT4 was unchanged. L remained decreased until the end of R1. After ET, a significant increase of TSH was found. L correlated to basal TSH levels (r = 0.49, p = 0.006) during R. BMI and body fat were unchanged throughout the study and were not correlated with hormonal levels. We speculate a high energy flux during intensified training (RT) caused the decrease of L and the HTA, independent of BMI or body fat. Thus, we conclude a depression of L and HTA is associated with training intensity.

Adolescent↗
PubMed2000

Training of junior rowers before world championships. Effects on performance, mood state and selected hormonal and metabolic responses.

BACKGROUND: Few data have been published on training of competitive athletes and about metabolic, hormonal and psychological reactions to overreaching (transient over-training) and tapering in successful athletes. METHODS: Training was recorded and effects on mood state and metabolic and hormonal responses were examined in 10 rowers and spares of the coxed eight during preparation for the World Championships 1995. Mood state was determined using the Recovery-Stress-Questionnaire for Athletes. Resting morning blood parameters as well as performance were measured every week over a period of five weeks. RESULTS: Very high training loads of approximately 3.2 hours per day were sustained for 18 days. Maximum performance (Pmax) and maximum lactate (Lamax) were decreased during high-load training phases (overreaching), Pmax, Lamax and endurance increased after the tapering period. There were decreases in gonadal and hypothalamic steroid hormones (fsh, 1h, prolactin, testosterone) during overreaching and increases in these hormones in tapering. Both performance and hormonal indices of training load were reflected by deterioration of recovery in the Recovery-Stress-Questionnaire for Athletes. CONCLUSIONS: Clear signs of overreaching were found after 18 days of intense training of about 3 h.d(-1) in these highly-trained athletes, i.e. decreases in performance, gonadal and hypothalamic steroid hormones and deterioration of recovery in the psychological questionnaire. After tapering values returned to baseline values before the World Championship. The findings indicate that overreaching is an integral part of successful training regimens and can be analyzed by a multi-factorial approach involving biological and psychometric data.

Adolescent↗
PubMed1998

Ultra-triathlon-related blood-chemical and endocrinological responses in nine athletes.

BACKGROUND: Objective of this study was to get more insight in hematology, biochemistry, and endocrinology of ultra-endurance exercise, to improve knowledge in this field, supplementation, and medical care of affected athletes. METHODS: A large body of individual hematological, biochemical, and endocrinological parameters was analyzed in the blood taken from ultra-athletes before and after completing the 1993 Colmar ultra triathlon covering 7.5 km swimming, 360 km cycling, and approximately 85 km running. PARTICIPANTS: Nine experienced ultra-athletes participated in the study. A follow-up was not possible since the athletes left Colmar within 24 hrs after the contest. RESULTS: The athletes finished the ultra-contest at rankings 4, 5, 7, 8, 9, 11, 18, 22, 23 in a total time between 23:38:53 and 27:54:30 hr:min:sec. Their final body mass (68.6 +/- 1 kg) was significantly lower than at baseline (71.9 +/- 4.2 kg). Non of the athletes made use of medical care. Data after this contest reflect mild hyponatremia, intravascular hemolysis, increased triglyceride turnover, acute-phase reaction, hyperaldosteronemia 2061 +/- 1013 pmol.L-1), hypercortisolemia 971 +/- 486 nmol.L-1), hyper-growth-hormonemia (median 6.8 ng.ml-1), hypoinsulinemia, hypo-free-testosteronemia (42 +/- 17 pmol.L-1), protein catabolism, depressed testicular function, oliguria, and muscle cell leakage. CONCLUSIONS: In our opinion, data presented do not reflect any acute health risks in healthy athletes who are well prepared and carefully supplied during such a contest.

Adult↗
PubMed1998

Monitoring intensive endurance training at moderate energetic demands using resting laboratory markers failed to recognize an early overtraining stage.

BACKGROUND: Aim was to answer the question whether resting laboratory parameters are suitable for monitoring intensive endurance training at moderate energetic demands. This was designed since markers of overtraining at high energetic demands, e.g. mild anemia, leukopenia, iron deficiency, reduced serum albumin, glucose, triglyceride, triglyceride-rich cholesterol (LDL, VLDL), free fatty acid, increased plasma noradrenaline levels, and decreased basal catecholamine excretions were recommended. METHODS: A prospective 6-wk, 6-dys/wk intensive steady state and interval cycle ergometer training of 40-60 min/dy was performed. Total load was about 6-time pretraining activities followed by a 2-wk, 2-hour/wk regenerative training period. Six recreational athletes (VO2max 51.5 +/- 4.5 ml.kg-1.min-1) participated and finished the study. A large pattern of resting hematological, blood-chemical, and hormonal parameters was tested regarding suitability for monitoring overtraining. RESULTS: After 3 wks, submaximum and maximum performance were significantly increased, stopped improving between wk 3 and 6, or deteriorated. No supercompensation occurred after regeneration, but a decrease in work output. Lack of progression and supercompensation, and decreased maximum work output indicate a critical stage in the training process. CONCLUSIONS: All examined resting laboratory parameters failed to reflect this critical stage except for a significant decrease in serum glucose, ferritin, and free fatty acid concentrations.

Adult↗
PubMed1996

[Primary pigmented nodular adrenocortical dysplasia. A rare cause of Cushing's syndrome].

HISTORY AND CLINICAL FINDINGS: A 29-year-old woman was found to have arterial hypertension (175/115 mm Hg). The 24-hour profile showed no diurnal cortisol variations with normal concentrations and 24-hour urinary cortisol was normal. 14 months later there was definite hypercortisolism with discrete Cushing signs and no amenorrhoea. She also had signs of depression. INVESTIGATIONS: Routine laboratory tests were unremarkable. ACTH and dehydroepiandrosterone levels were reduced and there was marked hypercortisolism (600 micrograms/24h). Bone densitometry showed osteoporosis. The low- and high-dose dexamethasone inhibition tests showed no suppression of 24-hour urinary cortisol, raising the suspicion of adrenal cortical adenoma or carcinoma. Magnetic resonance imaging (MRI) of both adrenals was normal, and scintigraphy showed physiological storage. MRI of the skull was normal. TREATMENT AND COURSE: As ACTH-independent hypercortisolism had been proven, unilateral adrenalectomy was performed. The specimen showed primary pigmented nodular adrenocortical dysplasia (PPNAD). While cortisol levels and blood pressure were at first normal, hypercortisolism had recurred 5 months postoperatively. The other adrenal was removed and showed a similar histology. A malignant melanoma of the shoulder was also found, perhaps part of a Carney syndrome. CONCLUSION: PPNAD should be included in the differential diagnosis of an ACTH-independent Cushing's syndrome with normal adrenal on imaging, perhaps as part of a Carney syndrome.

Adrenal Cortex↗
PubMed1995

Potential of endogenous peptides to induce immunological reactions as observed in type I diabetes, a study in mice.

The initiation of the immunological processes leading to type I diabetes is still not understood. The potential of endogenous peptides to induce autoimmune reactions was investigated. Peptides generated in the beta-cell by proteolysis could bypass antigen processing by binding to MHC molecules. Selfreactive T and B lymphocytes could be activated by these MHC peptide complexes. The antibody production of peptide-induced B lymphocytes was investigated in mice. Insulin A chain, B chain, C-peptide or amylin were tested for potential induction of antibodies to antigens other than the immunizing peptide. Lymph node B lymphocytes were characterized with an avidin at solid phase ELISA-spot assay. In BALB/c mice insulin A chain induced more spots to B29biotin- and to B1biotinDOP insulin than to A chain itself (P < 0.01, each). Spots to insulin were not inhibited by insulin A chain. Spots to B1DOP insulin were not inhibited by A chain or insulin, excluding crossreaction. Inbred strains of mice with H-2d but not with H-2k or H-2b showed the effect. Application of A chain without adjuvant produced the effect. The antigens recognized by A chain-induced B lymphocytes had to be included in the natural IgM antibody repertoire of the spleen. The study supports the hypothesis that endogenous breakdown peptides can bypass antigen processing resulting in an autoreactive T-B cell interaction. A potential to induce type I diabetes could exist.

Amyloid↗
PubMed1994

Insulin as a target antigen in autoimmune diabetes: a natural repertoire as the source of antibody response.

A solid-phase immunoenzymatic technique with B1- or B29-biotinylated insulin coupled to avidin-coated wells was used to characterize serum anti-insulin antibodies and to locate insulin antibody-producing B lymphocytes in different organs of mice. Low natural serum anti-insulin IgM and IgG antibodies were found in ten different healthy inbred strains of mice. Prediabetic non-obese diabetic (NOD) mice had significantly higher measurements than BALB/c mice (P < 0.05). Anti-insulin IgM antibody-producing B lymphocytes were found in bone marrow and spleen of NOD mice and healthy strains of mice, but not in peripheral lymph nodes, thymus, blood or pancreas. B29-fixed insulin was more frequently recognized than B1-fixed insulin. There was no relationship to the MHC or to other immune markers. IgG insulin antibody-producing cells were not detected. IgG insulin antibody-producing cells appeared in the draining lymph node and in the blood 10 days after immunization with insulin. IgM insulin-recognizing cells in the spleen were reduced in number during the same period (P < 0.05-0.01 for BALB/c, DBA2, B10.D2 and NOD), suggesting migration of these cells. This was tested by in vivo staining of spleens with the red-fluorescent membrane linker PKH-26 on day 7 after immunization. Cells from immunized lymph nodes were FACS-sorted on day 10. Insulin antibody-producing B lymphocytes with red-fluorescence were found, indicating a splenic origin. Examination of IgG subclasses showed preferential production of complement-fixing IgG2b in sera and lymph node cells of immunized NOD mice (P < 0.05 vs BALB/c).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Coincidence of hepatic angiosarcoma and insulin-resistance diabetes mellitus with high-dose intraperitoneal insulin therapy].

Angiosarcoma of the liver was diagnosed at autopsy in a 50 year old female with insulin-resistant diabetes mellitus. Over the course of 27 years, the patient received 27 l of Insulin-preparations applied subcutaneously and by an intraperitoneal pump-system. The preparations contained 20 g phenol. Known carcinogens for angiosarcoma of the liver-thorotrast, monovinylchloride or arsenic-were excluded. Phenol is a well known carcinogen of the skin and its tumor-promoting potential has been demonstrated in vitro. We suggest phenol as a potential aetiologic factor for angiosarcoma of the liver.

Autopsy↗
PubMed1993

In vivo labelling of the spleen with a red-fluorescent cell dye.

A method for labelling mouse spleen cells in situ is described. Spleen vessels were clamped before intrasplenic injection of a red-fluorescent cell dye (PKH-26). The labelling rate was 11.8% of all cells and 13.9% of B lymphocytes 30 min after injection as determined by FACS. 3 days later, the proportions of labelled cells were reduced to 7.4% (P < 0.01) and to 10.7% (P < 0.05), respectively. Only 10% of cells detected by FACS could be detected by fluorescence microscopy. Labelled cells were not found in peripheral lymph nodes 30 min after spleen injection, but were present 3 days later (FACS: 2.8% of all cells and 5.4% of B lymphocytes, P < 0.05 each), indicating migration of stained cells. Neither adverse nor toxic effects of in situ staining were observed. Isolated stained B lymphocytes from spleens of naive mice and from lymph nodes after immunisation with insulin showed proper function when tested in an ELISA-spot assay. The labelling procedure was used to follow splenic B lymphocytes producing natural anti-insulin antibody. These cells were found to be recruited for the early immune response in lymph nodes immunised with insulin.

Animals↗
PubMed1993

Glucose-induced water movement from the intracellular to the extracellular space and its influence on calculations of glucose metabolism.

The osmotic effect of intravenous glucose was investigated in eight healthy volunteers. Increases in plasma glucose can induce water movement from the intracellular to the extracellular space. Serum choline esterase was used as an endogenous marker of serum dilution. Intravenous tests with 5, 15, 30 and 35 g of glucose showed that the water shift was proportional to the amount infused. The respective dilutions of choline esterase were 1.3 +/- 0.7%, 3.3 +/- 0.9%, 6.3 +/- 0.8% and 7.8 +/- 0.5%. The effect on extracellular water was maintained when plasma glucose remained elevated (inhibition of insulin secretion with a somatostatin analogue). In comparison to glucose, infusion of 10 g of a mixture of amino acids produced a less pronounced effect than expected. The acute water shift after intravenous glucose dilutes serum components including glucose (8% of total extracellular glucose at 35 g). This can be misinterpreted as glucose clearance when calculating metabolic rates. For estimated amounts a proportional correction should be made (3.5% per 5 mmol l-1 increase). A measured plasma glucose of 22.2 mmol l-1 should be corrected to 24.8 mmol l-1, while a plasma glucose value of 5.0 mmol l-1 needs no correction.

Blood Glucose↗
PubMed1993

Influence of 6-week, 6 days per week, training on pituitary function in recreational athletes.

The influence on pituitary function of 6 weeks of training on 6 days a week was examined in six recreational athletes. Endurance training on a bicycle ergometer for 31-33 min was performed on 4 days each week at 90-96% (weeks 1-3) and 89-92% (weeks 4-6) of the 4 mmol lactate thresholds determined on day 0 and day 21, respectively, with interval training of 3-5 x 3-5 min in addition on 2 days a week at 117-127% and 115-110%, respectively. Determination of the serum hormone levels and a combined pituitary function test (200 micrograms thyrotropin releasing hormone (TRH), 100 micrograms gonadotrophin-releasing hormone (GnRH), 100 micrograms corticotrophin releasing hormone (CRH), 50 micrograms growth hormone releasing hormone (GHRH)) were made before training, after 6 weeks of training and after another 3 weeks of recovery. Training increased performance at 2 mmol lactate by 25%, at 4 mmol by 12%, and maximum performance by approximately 12%. The releasing hormone-stimulable prolactin, thyroid stimulating hormone (TSH) and somatotrophic hormone (STH) synthesis-secretion capacity remained unchanged, the adrenocorticotrophic hormone (ACTH) was increased after training. Cortisol release was reduced, follicle-stimulating hormone (FSH)-synthesis-secretion capacity was increased after training, and the luteinizing hormone (LH)-synthesis-secretion capacity reduced. This had no influence on base or exercise-induced serum hormone levels (cortisol, aldosterone, insulin, prolactin, FSH, LH, TSH, ACTH, ADH and STH), which showed no dependence on training, except for free testosterone which showed a decreasing trend (P < 0.10) of 19-25% and post-exercise ACTH which showed an increasing trend of 33% (P < 0.10). Conditioning (cortisol sensitivity and ACTH response) or adaptation (FSH and LH responses) to changed testosterone serum levels and altered spermatogenesis is discussed.

Adrenocorticotropic Hormone↗
PubMed1992

Osmotic stress due to changes in plasma glucose and its regulation in IDDM patients.

Intravenous glucose tolerance tests (30 g, 5 min, constant rate) were performed in 8 IDDM patients and in 8 controls. The consequences of the osmotic pressure, induced by glucose, were investigated. Serum choline esterase was used as an endogenous marker of serum dilution. Five minutes after the end of infusion plasma glucose was raised by 182 +/- 12 mg.dl-1 in patients and by 189 +/- 6 mg.dl-1 in controls. Choline esterase values decreased by 6.6 +/- 0.8% and 6.3 +/- 1.0% respectively, P less than 0.01 each. Calculated water shifts into the extracellular space were 924 +/- 112 ml and 882 +/- 140 ml respectively. Fifteen minutes after the end of infusion glucose decreased by 32 +/- 1 mg.dl-1 in IDDM patients and by 57 +/- 2 mg-1 in controls. Serum choline esterase recovered by 2.6 +/- 0.2% and 2.7 +/- 0.2% respectively, P less than 0.01 each, indicating comparable water correction in spite of the slower fall of glucose in IDDM patients. Water correction was more rapid than glucose fall. Diuresis (46 +/- 4 ml versus 42 +/- 3 ml) or cellular uptake of serum solutes (electrolytes, amino acids, urea, creatinine) could not explain this. It is hypothesized that accumulation of free intracellular glucose reduces the osmotic gradient and facilitates cellular water re-uptake.

Adult↗
PubMed1992

Training-overtraining: performance, and hormone levels, after a defined increase in training volume versus intensity in experienced middle- and long-distance runners.

Performance and hormones were determined in eight middle- and nine long-distance runners after an increase in training volume (ITV, February 1989) or intensity (ITI, February 1990). Seven runners participated in both studies. The objective was to cause an overtraining syndrome. The mean training volume of 85.9 km week-1 increased within 3 weeks to 176.6 km week-1 during ITV and 96-98% of training volume was performed as long-distance runs at mean(s.d.) 67(8)% of maximum capacity. Speed endurance, high-speed and interval runs averaging 9 km week-1 increased within 3 weeks to 22.7 km during ITI, and the total volume increased from 61.6 to 84.7 km. A plateau in endurance performance and decrease in maximum performance occurred during ITV, probably due to overtraining, with performance incompetence over months. Nocturnal catecholamine excretion decreased markedly (47-53%), contrary to exercise-related plasma catecholamine responses, which increased. Resting and exercise-related cortisol and aldosterone levels decreased. Improvement in endurance and maximum performance occurred during ITI indicating a failure to cause an overtraining syndrome in ITI. Decrease in noctural catecholamine excretion was clearly lower (9-26%), exercise-related catecholamine responses showed a significant decrease, cortisol and aldosterone levels remained almost constant, exercise-related prolactin levels decreased slightly. There were no differences in insulin, C-peptide, free testosterone, somatotropic hormone (STH), follicle stimulating hormone (FSH), luteinizing hormone (LH), thyroid stimulating hormone (TSH), tri-iodothyronine (T3) and thyroxine (T4). The decrease in nocturnal catecholamine excretion during ITV might indicate a decrease in intrinsic sympathetic activity in exhausted sportsmen. But it remains open whether this reflected a central nervous system incompetence.

Adult↗
PubMed1992

Pathophysiology of polyhydramnios in twin transfusion syndrome.

In 3 cases of severe twin transfusion syndrome we demonstrate that the concentration of atrial natriuretic factor (ANF) in the cord blood of recipient twins is significantly elevated compared to that of donor twins. The discrepancy between recipient and donor concentration correlates with the volume of transfusion. The following pathophysiological mechanism for explaining polyhydramnios in recipient twins is proposed: chronic overload in recipient twins causes enhanced release of ANF from the fetal heart. Consequently, increased fetal urine production leads to polyhydramnios, which is additionally enhanced by inhibition of ADH release.

Adult↗
PubMed1991

Sympathetic autonomic dysfunction. Programmed subcutaneous noradrenaline administration via microdosing pump.

Sympathetic dysfunction is characterized by postural hypotension, decreasing blood pressure without compensatory tachycardia during graded supine ergometric exercise, impaired catecholamine metabolism, and hypersensitivity to catecholamines. We report on eight patients, seven with sympathetic dysfunction, of whom three patients were treated for the first time with programmed subcutaneous noradrenaline administration by means of a microdosing pump over a time period of 1.5-13 months. A clear improvement in blood pressure values, orthostasis tolerance, and exercise capacity has been observed in these three patients which permit them to extend their action radius. Adjustment of the noradrenaline dose to the wide range of everyday stress and the possible occurrence of adrenoreceptor desensitization, however, remains a severe problem.

Adult↗
PubMed1991

Lack of beta 2-adrenoceptor induced long-acting effect on glucose tolerance in type 2 diabetic patients.

The long-acting effect of a 10-min pulse infusion of the beta 2-adrenergic agonist fenoterol on oral glucose tolerance tests in controls and in normotensive patients with type 2 diabetes mellitus on diet was compared. During an oral glucose load starting 2 h after fenoterol control persons showed hyperglycemia (area: 25,950 +/- 467 vs. 22,650 +/- 410, P less than 0.01), hyperinsulinemia (area: 13,980 +/- 1050 vs. 8160 +/- 405, P less than 0.02) and a pronounced fall of serum potassium (area: 775 +/- 26 vs. 748 +/- 25, P less than 0.02). The patient group showed no late response to fenoterol: plasma glucose (area: 51,000 +/- 382 vs. 51,300 +/- 413, n.s.), serum insulin (area: 7215 +/- 233 vs. 8280 +/- 410, n.s.), serum potassium (area: 748 +/- 26 vs. 750 +/- 24, n.s.). The data show that there is a defect of the beta 2-adrenergic long-acting effect on glucose metabolism and on insulin release in type 2 diabetes mellitus.

Adult↗
PubMed1991

Urine screening in outdoor volunteers: day versus night versus 24 hour collection.

Urine constituents were measured in 12 healthy outdoor volunteers on four occasions within a month. Day, night, and 24 hour collection periods were compared. Measurements made on the four occasions did not differ. The amount of water, creatinine, electrolytes, proteins, and enzymes were higher during the day (up to three fold, p always less than 0.05), while equal amounts of amino acids were excreted in the day and the night period. A comparison of all values from all individuals for all four sampling occasions showed that the variation was lowest in the 24 hour samples. Relating the values to creatinine did not consistently reduce the variation. Twenty-four hour samples correlated better with the day than with the night samples. Day and night samples did not correlate. Twenty-four hour collection is superior to day or night collection in healthy outdoor volunteers. Based on the normal variation of values found in the present study, criteria for suspected kidney damage and therefore for the withdrawal of drugs in pharmacological studies can be defined for each collection period.

Adult↗