Biomedical subjects

G Kuhn

Publications and source records attributed to G Kuhn.

At least 19 recordsLinked to original sources

PubMed2001

Circadian rhythm, shift work, and emergency medicine.

Human beings, like other living organisms, have physiologic systems that are cyclic in nature. Many of these systems have a circadian length. This provides for internal stability while at the same time enabling the organism to interact with the external environment and respond to changes in that environment. These physiologic systems, including those with a circadian length, can change timing as a result of environmental cues, such as the light-dark cycle or seasonal variations, but this takes time. When people engage in rotating or night shift work, the circadian rhythms are unable to quickly adapt to a rapidly changing activity schedule. This results in desynchronosis of many physiologic systems, including those with circadian timing. Because many emergency physicians engage in shift work, they are subject to the effects of circadian rhythm disruption. Research on the effect of desynchronosis on emergency physicians is sparse but has demonstrated negative effects. This article reviews the effect of desynchronosis on the health and productivity of physicians engaged in shift work.

Adaptation, Physiological↗

PubMed2001

Influence of structure on nickel-titanium endodontic instruments failure.

The purpose of this work was to investigate the process history on fracture life of nickel-titanium endodontics files. The results are based on microstructural investigations of nickel-titanium engine-driven rotary instruments based on X-ray diffraction, scanning electron microscopy, and microhardness tests. Endodontic files are very work-hardened, and there is a high density of defects in the alloy that can disturb the phase transformation. The microhardness Vickers confirmed these observations (dislocations and precipitates). The X-rays show that experimental spectrum lines are extended, typical of a distorted lattice. The surface state of the endodontic files (scanning electron microscopy) is an important factor in failure and fracture initiation.

Dental Alloys↗

PubMed2001

Feeding daidzein to late pregnant sows influences the estrogen receptor beta and type 1 insulin-like growth factor receptor mRNA expression in newborn piglets.

The present study was undertaken to determine the tissue-specific expression of estrogen receptor beta (ERbeta), and the effects of a daidzein supplement to the diet of pregnant sows on the expression of ERbeta, and type 1 insulin-like growth factor receptor (IGF-1R) genes in newborn piglets by using semi-quantitative RT-PCR. Eight sows received a dietary supplement of daidzein at a dosage of 8 mg per kg feed from day 85 of gestation, and six sows were used as controls. After parturition, 2 male neonatal piglets were selected from each litter for sampling. ERbeta mRNA was detected in intestine, lung, thymus, kidney, pituitary and hypothalamus tissues, but not in heart, adrenal, skeletal muscle, liver or placental tissues. Daidzein treatment significantly increased the birth weight of male piglets and markedly reduced the level of ERbeta mRNA in the hypothalamus, but not in the pituitary. An up-regulation of IGF-1R gene transcription was observed in skeletal muscles of newborn piglets. In addition, the IGF-1R mRNA was found to be most abundant in pituitary and hypothalamus, followed by skeletal muscle, thymus, and liver tissues in decreasing order. Our results demonstrate that (1) ERbeta is expressed in a tissue-specific manner in newborn piglets, (2) daidzein down-regulates ERbeta gene expression in the hypothalamus, possibly indicating central effects of daidzein, and (3) daidzein influences fetal growth associated with higher IGF-IR gene expression in skeletal muscle.

Analysis of Variance↗

PubMed2001

Effects of exogenous somatotropin during early gestation on maternal performance, fetal growth, and compositional traits in pigs.

The objective of this study was to determine the effects of maternal treatment with porcine somatotropin (pST) during early gestation on embryonic survival, fetal development, and internal environment for fetal growth. Sixty-two crossbred gilts received daily injections of either 3 mL of a placebo (control, n = 31) or 6 mg of pST (n = 31) from d 10 to 27 of gestation. Representative gilts were slaughtered on d 28, 37, and 62 of gestation. The remaining gilts were allowed to farrow. It was found that embryonic survival was not influenced by pST treatment (P > 0.10). However, pST affected the growth and composition of the maternal (endometrium) and fetal (chorion) parts of the placenta. Thus, endometrial RNA concentration tended to be increased by pST at d 37 (P = 0.15), and it was increased at d 62 (P < 0.05) of gestation, which is indicative of increased capacity for protein synthesis. At birth, placental chorion weight (P < 0.10) and contents of DM and protein (P < 0.05) were increased due to pST treatment, but no effects were detectable up to d 62 of gestation. Maternal pST treatment was effective at increasing nutrient supply to the embryo as suggested from elevated glucose concentrations in amniotic and allantoic fluids (P < 0.05) at d 28 of gestation. With regard to prenatal growth, embryonic DNA concentration was slightly elevated at d 28 (P < 0.10), but pST did not induce any changes in average embryonic, fetal, or neonatal weights. However, within litters, the birth weights of piglets in the 25% lowest weight group (LW) were increased by pST treatment vs control LW pigs (1,241+/-55 vs 1,099+/-59 g, P < 0.10). Thirty-eight neonates from 15 litters divided among the three weight groups were examined for body composition. The weight of the intestinal tract was increased above average after maternal pST treatment (P < 0.01). Additionally, the amounts of tissues such as bone (P = 0.12) and s.c. fat (P = 0.06), and of protein, fat (P = 0.10), and ash (P < 0.05) were increased, whereas the relative body composition remained unchanged by pST (P > 0.10). On average, muscle protein concentration was elevated due to pST (P < 0.01), and, in LW piglets, plasma IGF-I concentration was increased (P < 0.10). The results suggest that maternal somatotropin is a critical factor in early pregnancy capable of influencing placental nutrient transfer and placental growth. It thereby selectively improves the growth conditions for the smaller littermates.

Allantois↗

PubMed2000

Topiramate monotherapy in the maintenance treatment of bipolar I disorder: effects on mood, weight and serum lipids.

Topiramate is a newly developed anticonvulsant agent with possible mood-stabilizing properties. Little is known about the short- and long-term effects of topiramate monotherapy in bipolar disorder. We here present the case of a 60-year-old female bipolar patient who received topiramate alone as maintenance treatment after recovering from euphoric mania. During 7 months, she was free from new manic symptomatology and she was able to reduce her overweight by 16.5 kg. The patient who is known to have a strongly hyperthymic temperament described symptoms of fatigue and sedation and eventually discontinued topiramate monotherapy. When she presented again in our bipolar clinic, severe euphoric mania had developed. After hospitalization, she slowly responded to oral sodium valproate loading plus zotepine. Her weight increased again and so did her triglyceride serum levels. Topiramate treatment and discontinuation did not seem to affect cholesterol serum levels.

Adult↗

PubMed2000

The secretory response of the rat colon to the flavonol quercetin is dependent on Ca2+-calmodulin.

The dietary flavonol quercetin induces chloride secretion in rat intestine. To clarify the underlying mechanisms, experiments were performed in Ussing chambers with tissue from rat proximal and distal colon. Quercetin induced an increase in short-circuit current (Isc), which was largely independent of submucosal neurons, as it was not affected by the neurotoxin tetrodotoxin. The effect of quercetin was blocked by the calmodulin antagonists trifluoperazine and ophiobolin A and was diminished by a blocker of Ca2+ release from intracellular stores (TMB-8), whereas the muscarinic receptor antagonist atropine was ineffective. The quercetin-induced Isc was abolished in Ca2+-free solution. The flavonol was able to further increase Isc after maximal stimulation of the cAMP pathway by forskolin. The Isc increase by the flavonol was differently affected by two analogous phosphodiesterase inhibitors. Whereas 3-isobutyl-1-methylxanthine (IBMX) antagonized the effect of quercetin, 8-methoxymethyl-IBMX had no effect. Both phosphodiesterase inhibitors similarly influenced the Isc increase induced by forskolin. These results indicate that the chloride secretion induced by quercetin in rat colon depends on Ca2+ and calmodulin. The cAMP pathway and inhibition of phosphodiesterase appear not to be responsible for the secretory activity of the flavonol.

1-Methyl-3-isobutylxanthine↗

PubMed1999

Antibody titers to hepatitis B surface antigen among vaccinated emergency physicians: three years' experience with a wellness booth.

STUDY OBJECTIVE: To determine antibody titers to hepatitis B surface antigen (anti-HBsAg) among previously vaccinated emergency physicians and to assess the degree of compliance with Centers for Disease Control and Prevention (CDC) postvaccination guidelines. METHODS: A descriptive analysis was performed of anti-HBsAg titer determinations and vaccination surveys among a self-selected group of emergency physicians attending the annual scientific assembly of the American College of Emergency Physicians in 1995, 1996, or 1997. RESULTS: Of 943 participants, titer levels were found to be protective in 768 (81%), borderline in 45 (5%), and nonreactive in 130 (14%). A total of 337 participants (36%) had not obtained postvaccination titer determinations, as advised by the CDC. More than 50% reported an occupational exposure to blood products within the previous 2 years. CONCLUSION: Despite their high risk for exposure to blood products, many previously vaccinated emergency physicians were not in compliance with CDC postvaccination guidelines.

Centers for Disease Control and Prevention, U.S.↗

PubMed1999

Post mortem changes in Ca2+ transporting proteins of sarcoplasmic reticulum in dependence on malignant hyperthermia status in pigs.

Meat quality of pigs is dependent on biochemical and biophysical processes in the time course post mortem (p.m.) and is associated with the intracellular Ca2+ homeostasis. However, there is little known about changes in the Ca2+ transporting proteins controlling the Ca2+ uptake of sarcoplasmic reticulum (SR) in the time course p.m. In this study changes in the Ca2+ transporting proteins were investigated in homogenates of longissimus muscles of 4 malignant hyperthermia susceptible (MHS) and 6 malignant hyperthermia resistant (MHR) Pietrain pigs. Muscle samples were obtained at different time intervals: biopsy 2 h prior slaughtering and from the carcass immediately after exsanguination (0 h), 45 min, 4 h, and 22 h p.m. The SR Ca2+ uptake rate was measured immediately after homogenization with closed calcium release channel (CRC), with opened CRC and without manipulation of CRC. Additionally the SR Ca2+ ATPase activity was determined. The results show: (i) The ability of SR to sequester Ca2+ declined to about 60% in the first 45 min p.m. in MHS samples irrespective of CRC state, whereas in MHR samples this decline was about 5%; (ii) Ca2+ uptake and Ca2+ ATPase activity were not different between the biopsy and 0 h samples, i.e. the stress of slaughter was of no immediate influence; (iii) The Ca2+ ATPase activity of the SR declined at about the same rate as the Ca2+ uptake in both MHS and MHR pig samples in the course of time p.m.; (iv) In samples, taken immediately after exsanguination, the Ca2+ ATPase activity of MHS pigs was higher than that of MHR pigs. However, in samples taken 4 h p.m. Ca2+ ATPase activity of MHS pigs has declined to about 30% of the value at 0 h; (v) The CRC can be closed and opened in all samples up to 22 h p.m. and seems to be fully functional at all sampling times; (vi) The CRC of MHS pigs is almost fully open, whereas the CRC of MHR pigs is only partially open at all sampling times; (vii) The permeability of the SR membrane to Ca2+ (determined as the ratio of SR Ca2+ ATPase with and without ionophore A23187) is the same in both MHS and MHR and did not change with ongoing time; (viii) No uncoupling of uptake from ATP hydrolysis occurred up to 4 h p.m., but the coupling differed between MHS and MHR for all time intervals with lower values for MHS pigs. The results suggest that the decreasing Ca2+ uptake rate of homogenates, sampled at different times p.m., is essentially caused by changes in the Ca2+ pump and not by changes in the CRC or an increased phospholipid membrane permeability to Ca2+.

Animals↗

PubMed1998

Effects of treating young boars with a GnRH depot formulation on endocrine functions, testis size, boar taint, carcass composition and muscular structure.

A study was designed to determine the effects of triptorelin (Decapeptyl C.R.), a GnRH-agonist in a depot formulation, on androst-16-en-3-one (androstenone), LH, oestradiol and testosterone and on carcass composition and muscle structure in boars. Treatment with this highly potent GnRH analog ensured peptide release for 4 weeks when given to 18 animals at 135 days of age (group 1). Control animals (n = 20, group 2) received a saline injection. Blood samples (n = 10) were collected by venipuncture from each boar from 7 days before hormone treatment to 28 days after treatment. During the treatment period, three samples of back fat were taken by biopsy to determine the levels of androstenone and skatole. Testis size was determined at slaughter at 165 days of age. The treatment of boars with triptorelin increased concentrations of LH, oestradiol-17 beta, and testosterone for one day, followed by a decrease to base-line concentrations. The result of sensorial testing for boar taint detection at slaughter showed a slight reduction in this trait (0.76 vs. 0.99). The concentration of androstenone in the body fat of all treated animals was lower than the generally accepted limit of 0.5 microgram/g for the absence of boar taint, compared with the concentrations from 20 control animals among which 13 showed levels higher than this limit. The hormonal treatment significantly reduced the weight and size of the tests. There was no effect on skatole levels in backfat (0.141 vs. 0.150 microgram/g). The GnRH-agonist did not influence the carcass composition of treated boars. The muscle meat percentage was not significantly altered in the experimental group (51.39 vs. 50.50%). Overall, these results indicate that the use of this form of GnRH-agonist in a depot formulation offers a new possibility for reducing concentrations of androstenone which is mainly responsible for undesirable boar taint.

Adipose Tissue↗

PubMed1998

Adaptation and psychometric properties of the German version of the Dissociative Experience Scale.

We introduce the 'Fragebogen zu Dissoziativen Symptomen' (FDS), a German adaptation of the Dissociative Experience Scale (DES) which was developed to screen for dissociation within an ICD-10 framework. In addition to the original 28 DES items, the FDS contains 16 items covering dissociative phenomena included in the ICD-10, particularly pseudoneurological conversion symptoms. The psychometric properties of the FDS were studied in 927 clinical and nonclinical subjects from different diagnostic groups and compared to results of American studies. The scale had good test-retest reliability of .88, high internal consistency (split-half = .90, Cronbach's alpha = .94) and good construct validity. These results indicate that the FDS may be a valuable screen for dissociative psychopathology in German-speaking countries.

Adult↗

PubMed1998

[Comparison of the body image of healthy and psychiatrically and chronically ill children using the KBMT-K].

UNLABELLED: Initially some results from empirical studies regarding body satisfaction and differentiation of body experience of children are described. METHOD: In our study several groups of children showing different kinds of illness at the age of eight to twelve years were subjected to the "Körperbildmaltest für Kinder" (KBMT-K, Günter) (Colour-A-Person-Dissatisfaction-Test for Children), a depression inventory and an anxiety test. Furthermore we examined the children's body knowledge. We assessed two samples of children in psychiatric and psychotherapeutic inpatient treatment. The diagnoses were disruptive behaviour (n = 32) or emotional disturbances (n = 36). Three other groups were formed of children with somatic chronic illnesses (asthmatics (n = 47), inpatient diabetics (n = 34) and outpatient diabetics (n = 30)). We compared the test scores with those of healthy children. RESULTS: Only the younger (eight to ten years old) children of both samples showed a significantly lower body satisfaction in comparison to healthy children, the young girls with a chronic somatic illness having the lowest scores. Older girls with a chronic somatic illness (aged 11 or 12 years) had a significantly poorer differentiation of their body experience than the healthy peers, a finding we had not expected in advance. Comparing the different clinical samples with the healthy sample, only the emotionally disturbed children were significantly more dissatisfied with their own body. Whereas we were able to demonstrate by statistical analyses that in addition to the illness, depression and anxiety had an impact on body image, the knowledge of the body did not influence the above-mentioned concepts. The results are discussed.

Affective Symptoms↗

PubMed1998

[Questionnaire on dissociative symptoms. German adaptation, reliability and validity of the American Dissociative Experience Scale (DES)].

The "Fragebogen zu dissoziativen Symptomen (FDS)" represents the authorised German translation and adaptation of the "Dissociative Experience Scale" (DES; Bernstein and Putnam 1986). The original scale comprises 28 items covering dissociative experiences with regard to memory, identity, awareness and cognition according to DSM-III-R and DSM-IV. For the German version, 16 items were added to cover dissociative phenomena according to ICD-10, mainly pseudoneurological conversion symptoms. Reliability and validity of the German version were studied in a total sample of 813 persons and were compared to the results of the original version. Test-retest reliability of the FDS was rtt = 0.88 and Cronbach's consistency coefficient was alpha = 0.93, which is comparable to the results of the DES. The instrument differentiates between different samples (healthy control subjects, students, unselected neurological and psychiatric inpatients, neurological and psychiatric patients with a dissociative disorder and schizophrenics). The FDS is an easily applicable, reliable and valid measure to quantify dissociative experiences.

Dissociative Disorders↗

PubMed1997

Geological record and reconstruction of the late Pliocene impact of the Eltanin asteroid in the Southern Ocean.

In 1995, an expedition on board the research vessel FS Polarstern explored the impact site of the Eltanin asteroid in the Southern Ocean, the only known asteroid impact into a deep ocean basin. Analyses of the geological record of the impact region place the event in the late Pliocene (approximately 2.15 Myr) and constrain the size of the asteroid to be >1 km. The explosive force inferred for this event places it at the threshold of impacts believed to have global consequences, and its study should therefore provide a baseline for the reconstruction and modelling of similar events, which are common on geological timescales.

Aluminum Silicates↗

PubMed1997

Effects of porcine somatotropin on the chemical body composition and fat quality in growing-finishing pigs.

Seventy eight growing-finishing pigs (male castrates and females) of the cross-breed Pietrain x (Large White x German Landrace) were used to investigate the effects of pST treatment on the chemical composition of the body, the growth of adipocytes, and the fatty acid profile of the backfat. Intramuscular injections (1 or 3 mg pST) were administered daily from an average weight of 65 kg up to slaughter. After pST treatment significant changes in all studied characteristics were observed in barrows, whereas the females exhibited very small responses. The pST caused an increase of water and protein contents and a simultaneous decrease of lipid content especially in body parts rich in fat. Furthermore, the proportion of unsaturated fatty acids increased and the fat cell diameter decreased in the backfat.

Adipocytes↗

PubMed1997

Follow-up study among model and pattern makers in a German automobile company. Results of a second follow-up.

An historical follow-up study of 528 model makers in a German automobile company found an unusual pattern of mortality among these workers that included an increased risk of total cancer and tumors of the stomach, genitourinary organs, and the brain (Becker et al, 1992). Because of small numbers of cases and problems with the validity of causes of death, we carried out a second follow-up using data from the official mortality statistics and extending the observation period by five years. The new results did not confirm the previous observations of an increased risk of total cancer, cancer of the genitourinary organs, and tumors of the brain but confirmed indications of an increased risk of stomach cancer and suggested for the first time that there may be an increased risk of cancer of the intestine. Though the small numbers of cases did not allow statistical confirmation of these findings, they are consistent with the results of other studies recently conducted in the United States and published in this journal.

Automobiles↗

PubMed1996

Cultured astrocytes express biglycan, a chondroitin/dermatan sulfate proteoglycan supporting the survival of neocortical neurons.

Astrocyte-conditioned medium (ACM) supports the survival of rat E15 neocortical neurons. Using a microtiter assay for neuronal survival, we demonstrated that part of the survival activity is associated with a proteoglycan fraction obtained after two chromatographic steps: (1) preparative Q-Sepharose anion-exchange chromatography under non-denaturating conditions and (2) MonoQ chromatography in the presence of 8 M urea. Analytical SDS-polyacrylamide gradient gel electrophoresis of pooled active MonoQ-fractions (MQ-pool) revealed a broad proteoglycan band migrating with an apparent M(r) in the range of 150-400 kDa. Digestion of the MQ-pool with chondroitin-ABC-lyase yielded a major core protein of 50 kDa. In Western blots the high molecular weight (150-400 kDa) material as well as the 50 kDa core protein band were immunoreactive to chicken polyclonal antibodies raised against purified biglycan from rat meningeal fibroblasts. Northern blot analysis of total RNA prepared from highly enriched astrocyte cultures revealed a single 2.9 kb biglycan transcript. By using in situ hybridization we demonstrated that essentially all cells in these cultures expressed biglycan mRNA. Furthermore, highly purified biglycan from bovine cartilage was shown to markedly enhance survival of rat neocortical neurons. In conclusion, we have shown that astrocytes synthesize and release the small chondroitin/dermatan sulfate proteoglycan (CS/DSPG) biglycan, a molecule that was found to support survival of neocortical neurons in vitro.

Animals↗

PubMed1996

Assessment of knowledge, attitudes, and behaviors relative to cervical cancer and the Pap smear among adolescent girls in West Virginia.

BACKGROUND AND METHODS: Questionnaires assessing knowledge of, attitudes toward, and behaviors relative to cervical cancer and its prevention were administered to 279 tenth-grade girls. RESULTS: Eighty-four percent had heard of cervical cancer, and 83% had heard of the Pap smear. Sexual intercourse with multiple partners and cigarette smoking were risk factors identified by 65% and 40% of these students, respectively. Forty-eight percent reported being sexually active. This group, compared with those not sexually active, was more likely to 1) identify the Pap test as a test involving a vaginal examination, 2) use tobacco products, and 3) be exposed to tobacco smoke. The most common barriers to obtaining a Pap test reported by those sexually active were embarrassment (64%), pain/discomfort (57%), fear of cancer (27%), fear of parents discovering sexual activity (25%), and cost (13%). CONCLUSIONS: Based on the information obtained in this study, the authors recommend changes in school health programs that target adolescent girls: 1) risk factors and behavior should receive more emphasis, and 2) the pelvic examination and Pap test should be described in sufficient detail to address the issues of embarrassment, pain, and discomfort.

Adolescent↗

PubMed1995

Directing an emergency medicine residency: the problems and their potential solutions.

OBJECTIVE: To characterize the problems facing emergency medicine residency directors (EMRDs), to describe potential solutions, and to associate perceptions with anticipated duration in the position of EMRD. METHODS: A confidential questionnaire was mailed to the EMRDs at all Accreditation Council for Graduate Medical Education-approved programs. The survey included a problem and solution list constructed by a panel of EMRDs. The respondents were asked to rate problems using a Likert-like scale and were asked to indicate which of the listed solutions they had used and had found useful, or thought would be useful. Associations of these features and demographic variables with the intention to leave the position of EMRD within 5 years were sought. RESULTS: Eighty-seven of 93 EMRDs (93.5%) completed the survey. Their mean age was 40 years; 50% had been EMRDs for < 3 years. Most of the EMRDs (62%) had an associate EMRD, and 77% had at least one secretary. The EMRDs worked a median of 220 hours per month. Major problems included: insufficient time for the job (57%), career interfering with family needs (44%), and lack of adequate faculty help (38%). The most frequently cited and useful solutions included: attending education courses, self-reading on education and management techniques, and discussing problems with and seeking advice from others. Most (68%) of the EMRDs anticipated continuing as program director for < or = 5 years. Neither age, gender, previous amount of time in the position, number of hours worked, nor nature of the problems faced on the job was a significant predictor of which of the EMRDs anticipated leaving. CONCLUSIONS: Half the responding EMRDs were < 40 years of age, half had been EMRDs for < or = 3 years, and 68% anticipated continuing in their position for < or = 5 years. Major frustrations included lack of knowledge and time. Family and career conflicts were frequent. These problems are similar to those of program directors in other specialties. Some recommendations are made to assist EMRDs.

Adult↗