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1.
Food Funct ; 6(7): 2224-30, 2015 Jul.
Article in English | MEDLINE | ID: mdl-26068548

ABSTRACT

The maintenance of physical activity is crucial for the prevention and management of type 2 diabetes (T2D), and exercise induced changes including production of metabolites like ammonia can result in fatigue and exercise intolerance. Nutritional supplements may serve as an effective measure in supporting patients undergoing physical training by acting on their metabolism. This study investigates the effects of supplementation with α-keto acids (KAS) on exercise tolerance and glucose control in T2D patients. In a double-blind, placebo-controlled, randomized study 28 T2D patients underwent 6 weeks training on a cycle ergometer while they were supplemented with either a placebo or KAS (0.2 g kg(-1) body weight each day). The weekly training volume, power output at maximum and lactic threshold, leg muscle torque, the plasma concentration and 8 h urinary discharge of glucose, ammonia and urea were determined before and after the training as well as after one week of recovery. With KAS the patients did significantly more voluntary exercise (213 vs. 62 min, P < 0.01), reached a higher VO2max (27.3 vs. 24.8 ml min(-1) kg(-1)), higher power output (224 vs. 193 watts, P < 0.05) and greater endurance capacity (108 vs. 96 watts at lactic threshold, P < 0.05). Although the patients without KAS improved their glucose control after the training (P < 0.05), this effect could not be maintained after recovery as it was in the KAS group, where there was a prolonged benefit in glucose control. KAS also affected the ammonia and urea metabolism. KAS delivered supportive effects on the physical training along with a prolonged benefit in glucose control in T2D patients.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/physiopathology , Keto Acids/administration & dosage , Aged , Blood Glucose/metabolism , Diabetes Mellitus, Type 2/metabolism , Dietary Supplements/analysis , Double-Blind Method , Exercise , Female , Humans , Male , Middle Aged , Motor Activity/drug effects , Muscle, Skeletal/physiopathology
2.
Brain Res ; 1622: 137-48, 2015 Oct 05.
Article in English | MEDLINE | ID: mdl-26119913

ABSTRACT

Aging comes along with reduced gray matter (GM) volume in several cerebral areas and with cognitive performance decline in different cognitive domains. Moreover, regional GM volume is linked to specific cognitive sub processes in older adults. However, it remains unclear which regional changes in older individuals are directly associated with decreased cognitive performance. Moreover, most of the studies on this topic focused on hippocampal and prefrontal brain regions and their relation to memory and executive functioning. Interestingly, there are only a few studies that reported an association between striatal brain volume and cognitive performance. This is insofar surprising that striatal structures are (1) highly affected by age and (2) involved in different neural circuits that serve intact cognition. To address these issues, voxel-based morphometry (VBM) was used to analyze GM volume in 18 younger and 18 older adults. Moreover, several neuropsychological tests from different neuropsychological test batteries were applied to assess a broad range of cognitive domains. Older adults showed less GM volume than younger adults within frontal, striatal, and cerebellar brain regions. In the group of older adults, significant correlations were found between striatal GM volume and memory performance and between prefrontal/temporal GM volume and executive functioning. The only direct overlap between brain regions associated with regional atrophy and cognitive performance in older adults was found for the right caudate: older adults showed reduced caudate volume relative to younger adults. Moreover, caudate volume was positively correlated with associative memory accuracy in older adults and older adults showed poorer performances than younger adults in the respective associative memory task. Taken together, the current findings indicate the relevance of the caudate for associative memory decline in the aging brain.


Subject(s)
Aging/pathology , Aging/psychology , Caudate Nucleus/pathology , Memory Disorders/pathology , Adult , Aged , Association Learning , Attention , Cerebellum/pathology , Executive Function , Frontal Lobe/pathology , Gray Matter/pathology , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Middle Aged , Neuropsychological Tests , Organ Size , Young Adult
3.
Work ; 41 Suppl 1: 1778-81, 2012.
Article in English | MEDLINE | ID: mdl-22316971

ABSTRACT

Research activities to determine the need of recovery time at work were mainly performed in the 1970s and 1980s. Previous studies were largely based on expert opinions or were generated within small and non-representative groups. Often, laboratory experiments were carried out with a low number of subjects. Especially during the last decade, only little additional scientific knowledge was generated on this topic. The very resource intensive development of more detailed results based on the existing level of scientific knowledge is assumed as one reason for this. In general, it seems to be reasonable to continue further research on the knowledge generated in previous studies, but implement larger samples and more representative groups. Besides, according to monotonous manual work, more research is especially needed regarding relative operating forces and operation frequencies taken grip conditions and hand/body position into account.


Subject(s)
Fatigue/etiology , Fatigue/prevention & control , Rest , Workplace , Humans , Task Performance and Analysis , Workload
4.
Neuroscience ; 165(4): 1244-53, 2010 Feb 17.
Article in English | MEDLINE | ID: mdl-19925856

ABSTRACT

Executive working memory operations are related to prefrontal regions in the healthy brain. Moreover, neuroimaging data provide evidence for a functional dissociation of ventrolateral and dorsolateral prefrontal cortex. Most authors either suggest a modality-specific or a function-specific prefrontal cortex organization. In the present study we particularly aimed at the identification of different prefrontal cerebral areas that are involved in executive inhibitory processes during spatial working memory encoding. In an fMRI study (functional magnetic resonance imaging) we examined the neural correlates of spatial working memory processing by varying the amount of executive demands of the task. Twenty healthy volunteers performed the Corsi Block-Tapping test (CBT) during fMRI. The CBT requires the storage and reproduction of spatial target sequences. In a second condition, we presented an adapted version of the Block-Suppression-Test (BST). The BST is based on the original CBT but additionally requires the active suppression of visual distraction within the target sequences. In comparison to the CBT performance, particularly the left dorsolateral prefrontal cortex (BA 9) showed more activity during the BST condition. Our results show that the left dorsolateral prefrontal cortex plays a crucial role for executive controlled inhibition of spatial distraction. Furthermore, our findings are in line with the processing model of a functional dorsolateral-ventrolateral prefrontal cortex organization.


Subject(s)
Attention/physiology , Brain/physiology , Executive Function/physiology , Memory, Short-Term/physiology , Space Perception/physiology , Adult , Brain Mapping , Female , Humans , Magnetic Resonance Imaging , Male , Neuropsychological Tests , Prefrontal Cortex/physiology , Reaction Time , Young Adult
5.
Indoor Air ; 15 Suppl 10: 56-64, 2005.
Article in English | MEDLINE | ID: mdl-15926945

ABSTRACT

UNLABELLED: Profiles of factors affecting self-reported eye symptoms and objectively determined tear film characteristics have been examined and compared using data from 814 office workers. Multiple logistic regression analysis reveals significantly increased risks of subjective perception of eye symptoms for female gender, use of contact lenses and persons with health problems. A reduced break-up time (BUT) depends on personal criteria such as a history of eye disease and female gender. Age under 40 years, high relative humidity and formaldehyde exposure exceeding the 90th percentile are protective regarding BUT. For a thin lipid layer (as an indication of dry eyes) significantly increased risks are detected for high particle load, high endotoxin concentration and female gender. A thick lipid layer (as an indication of inflamed eyes) is significantly associated with a low educational level. The estimation of foam in the medial eye canthus seems to be unsuitable for evaluating indoor problems. The risk factor profiles agree on a few points only. The objectively examined thin lipid layer is the best eye-related indicator of the indoor environment. We therefore conclude that there is a need for the development and application of objective clinical methods for field monitoring in parallel with questioning. PRACTICAL IMPLICATIONS: Self-reported eye symptoms in conjunction with indoor environmental problems should be validated by objective medical examinations such as semi-quantitative estimation of the superficial lipid layer, measurement of the break-up time or assessment of conjunctival epithelial damage. For unbiased proof of environmental impact, personal factors such as acute illness or low job satisfaction should be excluded. As a minimum requirement, measurements of particles, NO(2) and relative humidity (and if possible endotoxin) should be carried out to detect any indoor environmental reason for eye symptoms.


Subject(s)
Air Pollution, Indoor/adverse effects , Eye Diseases/etiology , Adult , Age Factors , Contact Lenses , Female , Humans , Humidity , Inflammation , Male , Middle Aged , Risk Factors , Sex Factors
6.
Sci Total Environ ; 326(1-3): 143-9, 2004 Jun 29.
Article in English | MEDLINE | ID: mdl-15142772

ABSTRACT

In the context of environmental monitoring in Berlin polycyclic aromatic hydrocarbon (PAH) concentrations in air and household dust were measured inside 123 residences (and simultaneously in a sub group in the air outside the windows). The aim of this study was to determine exposure to PAHs in the environment influencing by several factors, for instance, motor vehicle traffic in a populous urban area. Indoor air samplings were carried out in two periods (winter and spring/summer) in smokers and non-smokers apartments. Benzo(a)pyrene (BaP) median values were 0.65 ng m(-3) (winter) and 0.27 ng m(-3) (spring/summer) in smokers' apartments and 0.25 ng m(-3) (winter) and 0.09 ng m(-3) (spring/summer) in the apartments of non-smokers. The median BaP content in ambient air was 0.10 ng m(-3) (maximum: 1.1 ng/m(-3)) with an indoor-outdoor mean concentration ratio of 0.9 in non-smoker households and 5.4 in smoker apartments. In household dust we obtained median values of 0.3 mg kg(-1) (range: 0.1-1.4 mg kg(-1)). We found a significant relation between indoor and outdoor values. Approximately 75% of the variance of indoor air values was caused by the corresponding BaP concentrations in the air outside the apartment windows. Otherwise a significant correlation between indoor air and household dust values cannot be found. Therefore, according to our results, it is suggested that the indoor PAH concentration in non-smoker apartments could be attributed mainly to vehicular emissions.


Subject(s)
Air Pollutants/analysis , Air Pollution, Indoor/analysis , Environmental Exposure , Polycyclic Aromatic Hydrocarbons/analysis , Dust , Environmental Monitoring , Germany , Humans , Risk Assessment , Smoking , Urban Population , Vehicle Emissions
7.
Indoor Air ; 14(2): 137-43, 2004 Apr.
Article in English | MEDLINE | ID: mdl-15009420

ABSTRACT

The correspondence between impact factor profiles of self-reported skin sensation and of objectively determined skin symptoms was examined using data from the ProKlimA project (1994-1999). A sub-sample of 925 office workers participated in measurements of skin hydration and sebum content and responded to a questionnaire assessing sensory perception. The calculation of multiple logistic regression models revealed a significant increased risk for female sex [Odds ratio (OR): 2.3; confidence interval (CI): 1.4-3.6], poor software (OR: 2.2; CI: 1.3-4.0), unfavorable job characteristics (OR: 1.8; CI: 1.1-2.8), allergic illness (OR: 1.5; CI: 1.1-2.2) and the use of skin cream (OR:2.6; CI: 1.6-4.4) on the subjective perception of skin sensation. Regarding the objective medical examination of the skin humidity a significant increased risk was detected for a high concentration of Total Volatile Organic Compounds (OR: 2.5; CI: 1.3-4.8) and a low relative humidity (OR:1.9; CI: 1.1-3.4). The likewise objectively measured low sebum content is not associated with environmental variables. The impact profiles on subjective vs. objective outcome variables differ in a clear and typical way. Skin related sensory perception is mainly influenced by job-related and personal impacts. Indoor environmental characteristics affect skin hydration. We conclude the need to develop, to adapt and to use objective clinical methods applicable for field monitoring parallel to questioning.


Subject(s)
Air Pollution, Indoor/adverse effects , Skin Diseases/etiology , Skin Physiological Phenomena , Adult , Female , Germany , Humans , Humidity , Male , Middle Aged , Occupations , Odds Ratio , Perception , Risk Factors , Sebum , Sick Building Syndrome/physiopathology , Skin Diseases/pathology
8.
Int Arch Occup Environ Health ; 75(3): 153-62, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11954982

ABSTRACT

OBJECTIVE: To co-ordinate the work of the main European research teams in the field of thermal factors in order to develop and improve significantly the methods presently available for assessing the risks of heat disorders encountered during work in hot conditions. METHOD: Each item from the required sweat rate model was reviewed on the basis of the most recent literature. A database with 1,113 laboratory and field experiments, covering the whole range of hot working conditions, was assembled and used for the validation. RESULTS: Influence of clothing ensemble on heat exchange: methods and formulas were developed that take into account the dynamic effects associated with forced convection and the pumping effect associated with body movements and exercise. Prediction of the average skin temperature: the model used in the required sweat rate standard ISO 7933 was extended to cover more severe conditions with high radiation and high humidity and different clothing and take into account the rectal temperature for the prediction of the skin temperature. Criteria for estimating acceptable exposure times in hot work environments: criteria were reviewed and updated concerning the maximum increase in core temperature and the acceptable water loss, for acclimatised and nonacclimatised subjects. These limits are intended to protect 95% of the population. Measuring strategy: a strategy was developed to assess the risks in any working situation with varying conditions of climate, metabolic rate or clothing. A detailed methodology was developed in three stages: an "observation" method for the recognition of the conditions that might lead to thermal stress; an "analysis" method for evaluating the problem and optimising the solutions; and an "expert" method for in-depth analysis of the working situation when needed. VALIDATION: the different results were used to prepare a revision of the interpretation procedure proposed in the ISO standard 7933. We validated the modified approaches using the database. This involved the whole range of conditions for which the model was extended, namely conditions with high and low radiation, humidity and air velocity as well as fluctuating conditions. Based on these results, the predicted heat strain model was developed: it is presently proposed as an ISO and CEN standard.


Subject(s)
Heat Stress Disorders/physiopathology , Occupational Exposure/analysis , Risk Assessment/methods , Workplace , Biomechanical Phenomena , Clothing , Europe/epidemiology , Heat Stress Disorders/epidemiology , Heat Stress Disorders/etiology , Heat Stress Disorders/prevention & control , Humans , Skin Temperature , Sweating
9.
Ann Occup Hyg ; 45(2): 123-35, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11182426

ABSTRACT

Eight laboratories participated in a concerted research project on the assessment of hot working conditions. The objectives were, among others, to co-ordinate the work of the main European research teams in the field of thermal factors and to improve the methods available to assess the risks of heat disorders at the workplace, and in particular the "Required Sweat Rate" model as presented in International Standard ISO 7933 Standard (1989). The scientific bases of this standard were thoroughly reviewed and a revised model, called "Predicted Heat Strain" (PHS), was developed. This model was then used to predict the minute by minute sweat rates and rectal temperatures during 909 laboratory and field experiments collected from the partners. The Pearson correlation coefficients between observed and predicted values were equal to 0.76 and 0.66 for laboratory experiments and 0.74 and 0.59 for field experiments, respectively, for the sweat rates and the rectal temperatures. The change in sweat rate with time was predicted more accurately by the PHS model than by the required sweat rate model. This suggests that the PHS model would provide an improved basis upon which to determine allowable exposure times from the predicted heat strain in terms of dehydration and increased core temperature.


Subject(s)
Body Temperature Regulation/physiology , Heat Stress Disorders/prevention & control , Occupational Diseases/prevention & control , Sweating/physiology , Algorithms , Heat Stress Disorders/physiopathology , Humans , Linear Models , Models, Biological , Occupational Diseases/physiopathology , Reproducibility of Results
10.
Indoor Air ; 11(4): 217-22, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11761596

ABSTRACT

Office workers often report so-called sick building syndrome (SBS) symptoms affecting the skin, mucous membranes and nervous system. The recurring higher prevalence of SBS in women was investigated using questionnaire and ergonomic data from the German ProKlimA-Project. The hypothesis that working conditions and job characteristics for women are inferior to those of men was tested for groups of risk factors. Finally, gender-specific multiple logistic regression models were compared. It was found that 44.3% of women (n = 888) and 26.2% of men (n = 576) suffer SBS with significant differences between men and women for many variables. Considering sub-groups--supposing the same circumstances in psycho-social and work-related conditions--gender-specific SBS prevalence rates differ as for the whole sample, e.g. 35.9% of women with the most favourable job characteristic suffer SBS (men: 19.4%), 53.0% of women with the most unfavourable job characteristic suffer SBS (men: 33.3%). These results show that women suffer more SBS than men independent of personal, most work-related and building factors. Multiple logistic models define self-reported acute illness, job satisfaction, software quality and job characteristics as significant gender-independent risk factors. Number of persons/room, self-reported allergy and smoking are characteristic female risk factors. Age is a significant risk factor only in men.


Subject(s)
Job Description , Perception , Sick Building Syndrome/physiopathology , Sick Building Syndrome/psychology , Adult , Female , Humans , Job Satisfaction , Male , Middle Aged , Prevalence , Regression Analysis , Risk Factors , Sex Factors , Sick Building Syndrome/epidemiology , Software , Surveys and Questionnaires
11.
Eur J Appl Physiol ; 82(1-2): 52-60, 2000 May.
Article in English | MEDLINE | ID: mdl-10879443

ABSTRACT

The prediction of the mean skin temperature used for the Required Sweat Rate index was criticised for not being valid in conditions with high radiation and high humidity. Based on a large database provided by 9 institutes, 1999 data points obtained using steady-state conditions, from 1399 experiments and involving 377 male subjects, were used for the development of a new prediction model. The observed mean skin temperatures ranged from 30.7 degrees C to 38.6 degrees C. Experimental conditions included air temperatures (Ta) between 20 and 55 degrees C, mean radiant temperatures (Tr) up to 145 degrees C, partial vapour pressures (Pa) from 0.2 to 5.3 kPa, air velocities (v(a)) between 0.1 and 2 m/s, and metabolic rates (M) from 102 to 620 W. Rectal temperature (T(re)) was included in the models to increase the accuracy of prediction. Separate models were derived for nude (clothing insulation, I(cl), < or = 0.2 clo, where 1 clo = 0.155 m2 x degrees C x W(-1), which is equivalent to the thermal insulation of clothing necessary to maintain a resting subject in comfort in a normally ventilated room, air movement = 10 cm/s, at a temperature of 21 degrees C and a humidity of less than 50%) and clothed (0.6 < or = I(cl) < or = 1.0 clo) subjects using a multiple linear regression technique with re-sampling (non-parametric bootstrap). The following expressions were obtained for nude and clothed subjects, respectively: T(sk) = 7.19 + 0.064Ta + 0.061Tr + 0.198Pa - 0.348v(a) + 0.616T(re) and T(sk) = 12.17 + 0.020Ta + 0.044Tr + 0.194Pa - 0.253v(a) + 0.0029M + 0.513T(re). For the nude and clothed subjects, 83.3% and 81.8%, respectively, of the predicted skin temperatures were within the range of +/- 1 degree C of the observed skin temperatures. It is concluded that the proposed models for the prediction of the mean skin temperature are valid for a wide range of warm and hot ambient conditions in steady-state conditions, including those of high radiation and high humidity.


Subject(s)
Environment , Hot Temperature , Skin Temperature , Clothing , Humans , Humidity , Linear Models , Male
12.
Int Arch Occup Environ Health ; 73(4): 215-20, 2000 May.
Article in English | MEDLINE | ID: mdl-10877026

ABSTRACT

OBJECTIVES: To revise the criteria used in the present "Required Sweat Rate" standard ISO 7933 (1989) for the prediction of the maximum duration of work in hot environments. METHODS: Review of the literature and in particular, of the bases for the present criteria. RESULTS: A new method is proposed, to take into account the increase in core temperature associated with activity in neutral environments. The prediction of maximum wetness and maximum sweat rates are revised, as well as the limits for maximum water loss and core temperature. CONCLUSION: An improved set of maximum values and limits is described, to be used in the revised version of the ISO 7933 standard. Due to the major modifications to the "Required Sweat Rate" index and in order to avoid any confusion, it is suggested that the revised model be renamed the "Predicted Heat Strain" (PHS) model.


Subject(s)
Hot Temperature , Occupational Health , Workplace , Ergonomics , Heat Stress Disorders , Humans , Occupational Exposure , Reference Values
13.
Ann Occup Hyg ; 43(5): 367-76, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10481637

ABSTRACT

A strategy in four successive stages is described and justified for the prevention and control of thermal problems in the workplace. This should allow these problems to be approached and solved progressively in small as well as large companies by relying successively, when necessary, on the complementary competencies of the workers themselves, their technical assistance, the occupational health specialists and the experts. The criteria to fulfil at each stage are described and discussed. Appendix 1 describes in detail the methods to be used at stages 2, "Observation" by the workers and their assistance; at stage 3, "Analysis" with the help of specialists; and outlines the stage 4, "Expertise".


Subject(s)
Heat Stress Disorders/diagnosis , Heat Stress Disorders/prevention & control , Mass Screening/methods , Occupational Diseases/diagnosis , Occupational Diseases/prevention & control , Research Design , Risk Assessment/methods , Algorithms , Bias , Body Temperature Regulation , Data Collection , Data Interpretation, Statistical , Heat Stress Disorders/physiopathology , Humans , Occupational Diseases/physiopathology , Occupational Medicine/methods , Professional Competence , Reproducibility of Results , Sensitivity and Specificity
14.
Transpl Immunol ; 7(1): 1-7, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10375071

ABSTRACT

In the clinical setting of solid organ transplantation the event of graft-versus-host disease (GvHD) is rare and not easily predictable. Even intestinal and multivisceral transplants harbour a huge amount of immunocompetent cells and they do not exert a significantly higher risk to trigger serious GvH reactions. A series of our own experimental studies has been conducted to delineate the role of the host's innate immune system in the context of GvHD following parental to F1 hybrid semiallogeneic small bowel transplantation (SBTx). These results clearly demonstrated the immunological significance of the recipient's status of natural killer (NK) cell activity to counteract donor-derived lymphocytes and related cytotoxicity. NK cells and macrophages are both endowed with Ca2+-dependent receptors of the C-type lectin family which interact with a diversity of high-affinity oligosaccharide ligands expressed on potential target cells. One of these proteins of the C-type lectin family, termed NKR-P1, has been cloned and sequenced. Activation of NKR-P1 stimulates activation-induced cell death (AICD) of bound target cells. As intracellular mediators of apoptotic cell death a new family of cysteine proteases, the caspases, have been defined. These proteases appear to be involved in the initiation of apoptosis in response to a number of stimuli. This study was conducted to investigate the impact on the activity level of host NK cells and on target cell lysis of donor-derived lymphocytes after heterotopic semiallogeneic (parental [DA;RT1.aaav1] to F1 [DA x LEW;RT1.(1)]) small bowel transplantation using a rat model. The host's NK activity was either specifically activated (by use of polyinosinic:polycytodilic acid [poly-I:C]) or suppressed (by depletion of host NK cells after intraperitoneal administration of the NKR-P1 monoclonal antibody 3.2.3). The impact of NK-activity on the incidence of GvHD and the recipients' survival was correlated with the frequency of apoptotic cell death and related expression of caspases 1 (ICE) and 3 (CPP-32) from donor and recipient small bowel tissues. Our results confirm that depletion of NK cells in F1 host rats prior to parental small bowel transplantation significantly decreased the mean survival to 11.4 days versus 16.2 days of nondepleted F1 rats (p < 0.01). Conversely, activation of host NK activity with poly-I:C abrogated GvHD in all 12 recipient rats and led to long-term survival in seven of 12 animals. Long-term survival was associated with a substantially higher frequency of apoptotic cell death in donor and recipient small bowel and mesenteric lymph nodes. On day 10 after transplantation, Northern blot analysis of these tissues revealed profound upregulation of mRNA-specific gene expression for caspase 1 and 3 as potential mediators of programmed cell death of activated lymphocytes. Our findings emphasize the importance of NK cell associated innate immunity in the context of GvHD after semiallogeneic small bowel transplantation. Killing of alloreactive donor-derived lymphocytes was mediated by the NKR-P1 protein on NK cells and could be suppressed after pretreatment of F1 hosts with anti-NKR-P1 mAb 3.2.3. Moreover, NK cell-mediated apoptosis induced upregulation of caspases 1 and 3, thus elucidating the involvement of this protein in the context of caspase-mediated target cell killing.


Subject(s)
Caspase 1/metabolism , Caspases/metabolism , Graft vs Host Disease/immunology , Intestine, Small/transplantation , Killer Cells, Natural/physiology , Animals , Apoptosis , Caspase 1/genetics , Caspase 3 , Caspases/genetics , Disease Models, Animal , Enzyme Activation , Killer Cells, Natural/immunology , Mice , Mice, Inbred BALB C , Rats , Rats, Inbred Lew , Transplantation, Homologous
15.
Shock ; 10(1): 26-31, 1998 Jul.
Article in English | MEDLINE | ID: mdl-9688087

ABSTRACT

Glutamine is an essential substrate for gut mucosal structure, but the role for gut immune function is not fully known. To determine the effect on gut cytokine release in relation to bacterial translocation and gut morphology, a nonlethal hemorrhagic shock (30 min, 30 mmHg) was performed in male Wistar rats followed by 4 days of different way of feeding. A conventional total parenteral nutrition (TPN) solution was compared with an isocaloric and isonitrogenous TPN solution supplemented with alanin-L-glutamine and glycyl-L-glutamine. An enteral chow-fed control group was included. Gut mononuclear cells and splenic macrophages were obtained and endotoxin-induced supernatant tumor necrosis factor-alpha (TNF) and interleukin-6 (IL-6) bioactivity was measured. Histological specimen of the small bowel were taken and mesenteric lymph nodes (MLN) were separated. Enteral feeding following hemorrhagic shock was accompanied by a normal mucosal structure and no bacterial translocation could be detected. TPN was characterized by suppression of cytokine release in gut mononuclear cells and splenic macrophages compared with the enteral-fed control (p < .05). Decreased TNF and IL-6 release was associated with a significantly increased mucosal injury score (p < .05) and a high incidence of bacterial translocation to MLN (66%, p < .05 vs. control). Supplementation of glutamine-dipeptides did not prevent TPN-induced bacterial translocation to MLN (p < .05 vs. control) but significantly improved mucosal injury (p < .05 vs. TPN). Down-regulation of TNF release in TPN-fed rats could not be reversed by glutamine dipeptides while IL-6 release was significantly increased compared with TPN-fed animals (p < .05), and no difference to enteral-fed controls could be found. Enteral nutrition following hemorrhagic shock is superior to parenteral nutrition with regard to mucosal structure, cytokine release, and bacterial translocation. Supplementation of TPN with glutamine dipeptides could reverse TPN-induced suppression of IL-6 release and improved mucosal structure, which may be beneficial in various disease conditions in which TPN is an integrated part of patients management.


Subject(s)
Dipeptides/pharmacology , Interleukin-6/metabolism , Intestinal Mucosa/drug effects , Shock, Hemorrhagic/drug therapy , Animals , Bacterial Translocation/drug effects , Cytokines/drug effects , Cytokines/metabolism , Interleukin-6/pharmacokinetics , Intestinal Mucosa/cytology , Intestinal Mucosa/ultrastructure , Macrophages/drug effects , Macrophages/metabolism , Male , Parenteral Nutrition , Rats , Rats, Wistar , Spleen/immunology , Tumor Necrosis Factor-alpha/drug effects , Tumor Necrosis Factor-alpha/metabolism
16.
Surg Endosc ; 11(8): 864-7, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9266654

ABSTRACT

Experimental studies demonstrated a severe cardiac load of the CO2 pneumoperitoneum caused by an accelerated after- and a decreased preload. Patients displaying cardiovascular risks are therefore often rejected from laparoscopic surgery. Hence, the pathophysiological changes and the intraoperative risk of the CO2 pneumoperitoneum in high-risk cardiopulmonary patients (NYHA II-III, n = 15) undergoing laparoscopic cholecystectomy are described. The changes in cardiac after- and preload seem to be due to the elevated intraabdominal pressure rather than transperitoneally resorbed CO2 and are reversible by desufflation. In one patient conversion to open operation had to be performed because of a severe drop in cardiac output and right ventricle ejection fraction. Mixed oxygen saturation was predicting intraoperative worsening in this case. The described pathophysiological changes may seem to be well tolerated even in high-risk cardiac patients. Monitoring of hemodynamics should include an arterial catheter line and blood gas analyses. Pharmacologic interventions or pressureless laparoscopic procedures might not be necessary as long as laparoscopic cholecystectomy is performed.


Subject(s)
Heart Diseases/physiopathology , Heart/physiopathology , Pneumoperitoneum, Artificial/adverse effects , Aged , Aged, 80 and over , Carbon Dioxide/adverse effects , Cardiac Output , Cholecystectomy, Laparoscopic/adverse effects , Female , Humans , Male , Middle Aged , Monitoring, Intraoperative , Oxygen/blood , Risk Factors , Stroke Volume
17.
J Invest Surg ; 8(6): 425-31, 1995.
Article in English | MEDLINE | ID: mdl-8751153

ABSTRACT

A new system for long-term vascular access in the unrestrained rat (n = 380) is described that combines low cost with high reliability and free movement. It consists of a polyurethane catheter that is placed in the right atrium via the external jugular vein. A leather harness is applied to the animal and the catheter passed subcutaneously to the neck into the harness. The harness is connected to the outside of a swivel joint via a silicone tube in which the catheter runs. The catheter is connected to the inside of the swivel. The swivel is a modified conventional 5-mL glass syringe and is positioned in ball bearings and a Johnson joint. Swivel, ball bearings, and the Johnson joint are counterbalanced and can move up and down. With this system all catheters functioned well until they were electively removed after 28 days. Four catheter dislocations resulted from harness failure and three from a twisted catheter. Seven cases of septicemia and eight of thrombosis occurred. All animals gained weight (3.53 +- 0.37 [SEM] g/d) during the time the system was in place. The entire apparatus is simple and inexpensive to construct. The rotary portion of the swivel and the Johnson joint avoid twisting of the catheter, and the counterbalance enables the animal to move up and down. The low thrombogenicity of polyurethane further reduced complications. This system reduces stress for the animal during long-term investigations.


Subject(s)
Cardiac Catheterization/instrumentation , Catheters, Indwelling , Movement , Animals , Cardiac Catheterization/adverse effects , Cardiac Catheterization/methods , Catheters, Indwelling/adverse effects , Equipment Design , Jugular Veins , Rats , Reproducibility of Results , Time Factors
18.
Fortschr Med ; 110(14): 265-7, 1992 May 20.
Article in German | MEDLINE | ID: mdl-1601375

ABSTRACT

Occlusion of the lumen by gallstones must be considered a rare cause of small bowel ileus; diagnosis and clinical symptoms have only sporadically been reported. The present paper shows that, in addition to gallstones, coproliths may also cause small bowel ileus, giving rise to identical clinical symptoms. For this reason, pre-operative diagnostic work-up should differentiate concretions in gallbladder and small bowel with respect to size, shape, consistency and X-ray contrast. If the stone proves to be a coprolith, the stenotic segment of bowel should be resected to prevent recurrences, while in the case of a gallstone, its manual manipulation across Bauhin's valve into the colon suffices.


Subject(s)
Cholelithiasis/complications , Ileal Diseases/etiology , Intestinal Obstruction/etiology , Cholecystectomy , Cholelithiasis/surgery , Female , Humans , Ileocecal Valve/surgery , Intestinal Obstruction/diagnosis , Intestinal Obstruction/surgery , Middle Aged , Recurrence
19.
Schweiz Rundsch Med Prax ; 79(51): 1586-8, 1990 Dec 18.
Article in German | MEDLINE | ID: mdl-2270384

ABSTRACT

The problems of surgical technique, graft physiology and immunological reactions in small-bowel transplantation have been investigated in extended animal experiments. In these experiments, the fundamentals of a successful clinical application of small-bowel transplantation could be laid. A successful human small-bowel transplantation could be carried out by the Kiel Group for the first time in 1988. A graft which had been removed from a related donor showed a complete adaptation after 22 months, so that the patient became completely independent from parenteral nutrition. After that, in several cases small-bowel and combined liver and small-bowel transplantation have been carried out. Thus, the clinical small-bowel transplantation represents the causal therapy of short-bowel syndrome and should be developed in further clinical trials.


Subject(s)
Intestine, Small/transplantation , Short Bowel Syndrome/surgery , Adult , Animals , Female , Graft Survival , Histocompatibility Testing , Humans , Immunosuppressive Agents , Rats , Transplantation Immunology
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