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Biomedical subjects

J Bahr

Publications and source records attributed to J Bahr.

At least 19 recordsLinked to original sources
PubMed2003

[To resuscitate or not? The emergency physician's decision in the prehospital setting].

OBJECTIVE: To identify factors affecting the decision to withhold resuscitative attempts or to terminate cardiopulmonary resuscitation (CPR) in the prehospital setting. METHODS: In a physician-based emergency medical system (EMS) standardised interviews with the emergency physicians were performed within 24 hours after unsuccessful or withheld CPR-efforts. RESULTS: Over a period of one year 170 prehospital cardiac arrests were evaluated. 47 patients (28 %) were declared dead on arrival by the emergency physician. The decision to withhold CPR was based on obvious clinical signs of death (32 patients) or the diagnosis of cardiac arrest due to severe trauma (8 patients). In 4 cases the terminal state of a fatal illness was the emergency physician's criterion not to initiate resuscitative efforts. In 3 patients an extended response time (more than 10 minutes) was mentioned, in combination with a primary rhythm of either asystole or electromechanical dissociation and additional information given by the family doctor. In 123 patients CPR was attempted. In 72 cases (59 %) resuscitative efforts were terminated as no return and stabilisation of spontaneous circulation was achieved. In 58 patients the decision to stop CPR was based on the evidence of cardiac death. Additional criteria for the termination of the resuscitation attempt were the duration of CPR, an extended response time, pre-existing diseases, age, pupillary status, missing brain stem reflexes, the reason of cardiac arrest, information given by the family or the family doctor and secondarily evolving signs of death. In 14 patients the emergency physicians reported that their decision to terminate CPR was primarily based on these co-factors, the evidence of cardiac death was not explicitly mentioned in these cases. CONCLUSION: In the pre-hospital setting the decision to withhold or to withdraw CPR is mostly based on reliable criteria such as obvious clinical signs of death, fatal trauma or evidence of cardiac death. Nevertheless, in a small but considerable number of cases exceptions to this rule are made by emergency physicians.

Adolescent↗
PubMed2003

Surface and intracellular Fas expression associated with cytokine-induced apoptosis in rodent islet and insulinoma cells.

During the process of insulitis in the pathogenesis of type I (insulin-dependent) diabetes mellitus, proinflammatory cytokines induce expression of the death receptor Fas on the surface of pancreatic beta-cells and thereby contribute to the enhanced susceptibility of beta-cells for apoptosis. The aim of this study was to compare cell-surface and intracellular Fas expression associated with cytokine-induced apoptosis in commonly used beta-cell models such as isolated islets and insulinoma lines derived from mouse and rat. The cell line NIT-1 responded to the interleukin (IL)-1beta+interferon (IFN)-gamma stimulus with translocation of Fas to the cell surface. Likewise, islet cells from non-obese diabetic (NOD) mice and BB/OK rats expressed increasing amounts of the Fas receptor on their surfaces after exposure to IL-1beta in combination with IFN-gamma and tumour necrosis factor-alpha. Moreover, islets obtained from BB/OK rats at an age near the onset of diabetes had an increased surface expression of Fas compared with young rats. In contrast, western blot analysis of cell lysates from cytokine-exposed islets and insulinoma cells revealed total Fas expression levels comparable to those of untreated controls. In conclusion, islets from BB/OK rats and NOD mice, in addition to NIT-1 insulinoma cells, responded to cytokine exposure with surface expression of the Fas receptor, whereas in cell lysates the levels of expression of Fas were found to be independent of cytokine exposure. Taken together, the findings indicate that cytokine-treated beta-cells might possess two pools of Fas protein, one of which is inducible by cytokines and accounts for surface Fas expression, whereas the other is constitutively expressed in cytoplasmic compartments. The underlying mechanisms, including possible interactions between these two sources of cellular Fas expression, need to be investigated in future studies.

Animals↗
PubMed2002

Cell surface trafficking of Fas in NIT-1 cells and dissection of surface and total Fas expression.

The appearance of Fas receptor at the surface of pancreatic beta-cells affected by progressive insulitis strongly suggests that Fas-mediated beta-cell apoptosis plays an important role in the pathogenesis of type 1 diabetes. In support of this concept, the present study has shown that islet cells from NOD mice and the beta-cell line NIT-1 respond to the proinflammatory cytokines IL-1beta and IFN-gamma with Fas surface expression in a dose- and time-dependent manner. Moreover, the prevention of cytokine-induced surface Fas expression by actinomycin D, cycloheximide, and brefeldin A demonstrated that trafficking of Fas to the beta-cell surface requires RNA and protein synthesis and, in addition is critically dependent on intracellular protein transport. Compared with total cellular Fas protein, the amount of Fas at the cell surface was relatively small and indicated that Fas is preferentially expressed in cytoplasmic compartments of NIT-1 cells. It is concluded that inflammatory insults specifically induce translocation of Fas to the beta-cell surface and that interference with cell surface Fas expression is a new strategy to improve beta-cell survival in inflamed islets.

Animals↗
PubMed2001

Oestrogen, its receptors and function in the male reproductive tract - a review.

Oestrogen is synthesized in the male reproductive system by at least three different cell types; Sertoli, Leydig and germ cells. Although testosterone is recognized as the primary sex steroid in man, oestrogen is produced in sizable quantities in the testis, as well as the brain and is found in extremely high concentrations in the semen of several species. The high concentration of oestrogen in rete testis fluid of the rodent is now thought to be derived from the conversion of testosterone to estradiol by P450 aromatase in germ cells of the testis and spermatozoa traversing the reproductive tract. This new major source of oestrogen would target oestrogen receptors in the male reproductive tract, in particular the efferent ductules, which contain the highest concentration of oestrogen receptor-alpha. This recent data raises new hypotheses regarding the role of oestrogen in the function of the male reproductive system. The oestrogen receptor-alpha knockout mouse was used to help define the function of oestrogen in the male. It was found that oestrogen receptor-alpha is essential for fluid reabsorption in the efferent ductules and in the absence of expression the male is infertile.

Animals↗
PubMed2001

[Attempted CPR in nursing homes - life-saving at the end of life?].

AIM: We studied the course and success rate of cardiopulmonary resuscitation (CPR) attempted on nursing home residents by a physician-staffed pre-hospital advanced cardiac life support (ACLS) team. METHODS: Ambulance records of nursing home residents from Goettingen/Germany who had a cardiac arrest were examined retrospectively. RESULTS: During a seven-year period (1992 - 1998) the ACLS team was called to 71 residents (mean age 81.8 years) who sustained cardiac arrest. In 25 patients no CPR was attempted: 20 were pronounced dead by the arriving emergency physician, though only in 7 patients obvious clinical signs of death were present. Five patients suffered from a continuous deterioration of their health status and the ACLS team arrived after the process of dying had already started. No CPR attempt was initiated. The ACLS team performed CPR on 46 nursing home residents. In 33 patients (72 % of CPR attempts) no return of spontaneous circulation (ROSC) was achieved. In three patients (6%) palpable pulse returned only transiently. Ten patients (22 %) who showed ROSC were transported to the hospital. Six patients died within 24 hours after having been admitted to the hospital, two patients within the next 8 days. Two patients survived to hospital discharge. The first was a 79-year old woman who returned to the nursing home after three weeks and survived severely mentally disabled another five days. The second was an 83-year-old man who was hospitalised for 20 days, returned in a persistent vegetative state to the nursing home and died 10 months later. A comparison of the arrest characteristics demonstrated that in patients with successful CPR there was a higher incidence of a witnessed collapse, bystander CPR, ventricular fibrillation and cardiac aetiology of arrest. CONCLUSION: In a high rate (35 %) the ACLS team with the emergency physician at the scene withheld CPR efforts in nursing home residents. Even if CPR was initiated, the benefits were very limited with only two patients (4,3 %) surviving severely disabled to hospital discharge.

Aged↗
PubMed2001

Estrogen regulation of ion transporter messenger RNA levels in mouse efferent ductules are mediated differentially through estrogen receptor (ER) alpha and ER beta.

Earlier studies have shown that the efferent ductules (ED) of the male mouse are a target for estrogen. The loss of estrogen receptor (ER) function through either knockout technology (alpha ERKO mouse) or chemical interference (pure antagonist, ICI 182 780) results in a failure of a major function of the ED, the reabsorption of testicular fluids. The purpose of this study was to test the hypothesis that estrogen controls fluid (water) reabsorption in the ED by modulating ion transporters important for passive water movement through a leaky epithelium such as the ED. Northern blot analysis was used to detect the mRNA levels for key ion transporters in the following experimental groups: 1) wild-type (WT) control for the 14-day experiment, 2) ER alpha knockout (alpha ERKO) control for the 14-day experiment, 3) WT treated with ICI 182 780 (ICI) for 14 days, 4) alpha ERKO treated with ICI for 14 days, 5) WT control for the 35-day experiment, and 6) WT treated with ICI for 35 days. Estrogen differentially modulated the mRNA levels of key ion transporters. ER alpha mediated carbonic anhydrase II mRNA abundance, and there was a decrease in Na(+)/H(+) exchanger 3 mRNA levels in the alpha ERKO that appeared to be a cellular effect and not a direct estrogen effect. The loss of ER alpha control resulted in an increase in mRNA abundance for the catalytic subunit of Na(+)-K(+) ATPase alpha 1, whereas an increase in the mRNA abundance of the Cl(-)/HCO(3)(-) exchanger and the chloride channel cystic fibrosis transmembrane regulator was significantly ER beta mediated. Our results indicate for the first time that estrogen acting directly and indirectly through both ER alpha and ER beta probably modulates fluid reabsorption in the adult mouse ED by regulating the expression of ion transporters involved in the movement of Na(+) and Cl(-).

Animals↗
PubMed1999

Resuscitation in Europe: a tale of five European regions.

AIM: To describe cardiac arrest data from five emergency medical services (EMS) systems in Europe with regard to survival from an out-of-hospital cardiac arrest. METHODS: Based on recommendations from various countries in Europe EMS systems were approached with regard to survival from out-of-hospital cardiac arrest. Five EMS systems were asked to report their cardiac arrest data according to the Utstein style. RESULTS: The five selected EMS systems were: Bonn (Germany), Göttingen (Germany), Helsinki (Finland), Reykjavik (Iceland) and Stavanger (Norway). For patients with a bystander witnessed arrest of cardiac aetiology the percentage of patients being discharged alive from hospital in these regions were: 21, 33, 23, 23 and 35. The corresponding percentages for patients fulfilling criteria as above and being found in ventricular fibrillation were: 32, 42, 32, 27 and 55. CONCLUSIONS: Many EMS systems in Europe show extremely good results in terms of survival after an out-of-hospital cardiac arrest. Some of the results should be interpreted with caution since they were based on relatively small sample sizes. Furthermore, the results from one of the regions (Stavanger) was unit based and not community based.

Cardiopulmonary Resuscitation↗
PubMed1999

[Emergency and intensive care medicine as an interdisciplinary training requirement].

While substantial and practical qualification for medical practice within the framework of emergency medical services have to be proven by an advanced training, there are no special training programs for in-hospital emergency situations. As in the emergency room a transparent in-hospital emergency management has to be established including definite competencies to avoid time delays and inadequate treatment due to disputes about competence. Especially surgical intensive care medicine is an interdisciplinary task, requiring the participation of the surgeon as a responsible partner. Thus, the physician working in ICUs needs professional qualification and specialized knowledge as well as marked competence to co-operate. In any case the final clinical responsibility has to be taken over by physicians who not only have performed their internship on a ICU but are highly qualified in the whole range of intensive care medicine including all topics required in advanced intensive care medicine curricula.

Clinical Competence↗
PubMed1997

A role for oestrogens in the male reproductive system.

Oestrogen is considered to be the 'female' hormone, whereas testosterone is considered the 'male' hormone. However, both hormones are present in both sexes. Thus sexual distinctions are not qualitative differences, but rather result from quantitative divergence in hormone concentrations and differential expressions of steroid hormone receptors. In males, oestrogen is present in low concentrations in blood, but can be extraordinarily high in semen, and as high as 250 pg ml(-1) in rete testis fluids, which is higher than serum oestradiol in the female. It is well known that male reproductive tissues express oestrogen receptors, but the role of oestrogen in male reproduction has remained unclear. Here we provide evidence of a physiological role for oestrogen in male reproductive organs. We show that oestrogen regulates the reabsorption of luminal fluid in the head of the epididymis. Disruption of this essential function causes sperm to enter the epididymis diluted, rather than concentrated, resulting in infertility. This finding raises further concern over the potential direct effects of environmental oestrogens on male reproduction and reported declines in human sperm counts.

Animals↗
PubMed1997

The decision to terminate resuscitative efforts: results of a questionnaire.

Despite all the progress made in emergency medicine, out-of-hospital resuscitative efforts still remain unsuccessful in the majority of cases and a decision concerning termination of cardiopulmonary resuscitation (CPR) has to be made. We used a multi-question survey to assess the attitude of emergency physicians towards the duration of an unsuccessful resuscitation attempt in non-traumatic cardiac arrest, and to identify the criteria affecting the decision to terminate CPR in the prehospital setting. More than 400 physicians participated in the inquiry on CPR in adults. If spontaneous circulation cannot be restored, the majority (65%) abandon the resuscitation attempt at the latest after performing advanced cardiac life support for 45 min. The participants indicated the following factors as criteria for the termination of unsuccessful CPR: pre-existing diseases (92%), presumed interval between onset of arrest and application of CPR (92%), duration of the resuscitation attempt (90%), age of the patient (89%), electrocardiographic (ECG) alterations such as persistent asystole/ventricular fibrillation or electromechanical dissociation (83%), persistent fixed and dilated pupils (78%), lack of brain stem reflexes (31%), body temperature (12%) and suspected drug intoxication (8%). The answers reflect the physicians opinions on termination of CPR even if they do not present real decisions under emergency conditions. The results indicate that in addition to the failure to restore spontaneous circulation, other factors are involved in decision making at the scene. A high rate of respondents include criteria of weak diagnostic value such as the pupillary status, or factors of doubtful prognostic significance such as the patient's age. Concerning the patient's history and underlying diseases, the emergency physician often has to resort to presumptions. We conclude that the decision to terminate CPR is made by most physicians considering the specific circumstances of the cardiac arrest.

Adult↗
PubMed1997

Skills of lay people in checking the carotid pulse.

American Heart Association as well as European Resuscitation Council require the carotid pulse check to determine pulselessness in an unconscious victim and to decide whether or not cardiopulmonary resuscitation (CPR) should be initiated. Recent studies on the ability of health professionals to check the carotid pulse have called this diagnostic tool in question and led to discussions. To contribute to this discussion we performed a study to evaluate skills of lay people in checking the carotid pulse. A group of 449 volunteers (most had participated in a first aid course) were asked to check the carotid pulse in a young healthy, non-obese person by counting aloud the detected pulse rate. Time intervals until correct detection of the carotid pulse were registered. Overall the volunteers needed an average of 9.46 s, ranging from 1 to 70 s. Only 47.4% of the volunteers were able to detect a pulse within 5 s, and 73.7% within 10 s. A level of 95% volunteers detecting the pulse correctly was reached only after 35 s. Based on these findings we conclude that the intervals established for carotid pulse check may be too short and that perhaps the value of pulse check within in the scope of CPR needs to be reconsidered.

Adult↗
PubMed1996

Influence of different types of recovery positions on perfusion indices of the forearm.

BACKGROUND: Basic life support guidelines of the European Resuscitation Council (ERC) suggest a modified type of recovery position compared to that recommended by the American Heart Association (AHA). However, anecdotal reports and the results of a small study by Fulstow and Smith (Resuscitation 1993; 26: 89-91) gave evidence that the new ERC position may cause an impairment of perfusion of the lower forearm. The aim of our study was to evaluate the effects of different recovery positions on arterial perfusion and venous drainage of the forearm. METHODS: We placed 20 young healthy volunteers randomly in either ERC or AHA position for 15 min first, and in the other position thereafter. Before and between volunteers were positioned supine. In a second series 10 volunteers were positioned according to the same protocol in semiprone positions as described by Morrison, Mirkhur and Craig (MMC), and Rautek's position, respectively. Forearm perfusion indices of the dependent arm were continuously assessed by photoplethysmographic pulsatility change, photoplethysmographic volume change, invasive peripheral venous pressure and non-invasive blood pressure amplitude. Subjective discomfort was assessed non-qualitatively. RESULTS: All indices of arterial perfusion demonstrated an impairment of arterial inflow in ERC, MMC and Rautek's position as well as venous congestion in these three positions. On the contrary, AHA position was associated with no significant changes of arterial flow and only moderate, insignificant signs of venous congestion. CONCLUSION: The results of this study suggest that AHA position causes less circulatory disturbances than the ERC, MMC and Rautek's positions.

Adult↗
PubMed1996

ACD versus standard CPR in a prehospital setting.

BACKGROUND: Animal and human studies in cardiac arrest demonstrate significant improvements in systolic blood pressure, coronary perfusion pressure and total brain and myocardial blood flow with active compression-decompression (ACD) cardiopulmonary resuscitation (CPR). The results of recent studies in patients with out-of-hospital cardiac arrest and use of ACD-CPR are non-uniform and require supplementation. METHODS: In a retrospective non-randomised design, 152 adult patients with prehospital cardiac arrest, not caused by trauma or hypothermia, were studied. Compressions were performed according to the recommendations of the American Heart Association. Three ACD devices were assigned to seven rescue units changing monthly. Study end-points were the rates of return of spontaneous circulation (ROSC), admission to hospital, survival at 24h, hospital discharge and neurologic outcome. RESULTS: 70 (46%) patients underwent standard (STD) CPR and 82 (54%) patients were treated with ACD-CPR. Both groups were comparable with regard to age, sex, witnessed cardiac arrests, bystander CPR, cause of arrest, time intervals, number of defibrillations, and total amount of epinephrine. No significant differences in outcome could be found: 20 patients (29%) who received STD-CPR, and 14 patients (17%) who underwent ACD-CPR survived to hospital discharge. Neither at other end-points nor in any subgroups could any significant differences be discovered. Patients regaining ROSC showed a significant difference in favour of STD-CPR for the end-points of hospital admission, 24-h survival and hospital discharge. CONCLUSION: No significant differences in hospital discharge and neurological outcome were found between STD-CPR and ACD-CPR.

Adult↗
PubMed1995

Characteristics of residents with do-not-resuscitate orders in nursing homes.

We determined patient characteristics associated with do-not-resuscitate (DNR) status in nursing homes using cross-sectional analysis of secondary data derived from Minimum Data Set documents in 14 nursing homes from one state in the upper Midwest. The primary outcome variable was DNR status. Bivariate analysis was first carried out on all variables. Variables associated with DNR status at this stage were then included in a stepwise logistic regression to determine variables independently associated with DNR status. Overall, 71% of patients had DNR orders. Variables found to be independently associated with a higher probability of DNR status were increasing age, female gender, worse cognitive function, durable power of attorney, being self-paying, or having commercial insurance. Lack of daily contact with relatives and friends and lack of involvement with others were associated with lower probability of DNR status. A higher prevalence of DNR status in nursing homes was seen than in prior literature. The patient characteristics shown to be associated with DNR status may give important insight into the reasons that such decisions are made.

Age Factors↗
PubMed1994

A comparison of two different European EMS centers (Brugge and Göttingen) using the same electronic 'cardiopulmonary-cerebral-resuscitation' registration program: a preliminary report.

A preliminary comparison of out-of-hospital cardiac arrest (CA) data registered with a common software program (Utstein style) in two different European EMS centers is presented. Rather than attempting independently several small-scale trials, we prefer to develop in a committed effort a coordinated program of active and passive surveillance. Hopefully, this will allow us to determine the true European profile and outcome of our out-of-hospital CA victims.

Belgium↗
PubMed1994

[Laser Doppler: new diagnostic possibilities in gestosis].

To evaluate the Laser-Doppler flowmeter (LD) as a diagnostic tool in microcirculatory alterations of gestosis, cutaneous circulation was measured in the forearm under basal conditions and during reactive hyperaemia by means of an MBF3D (Moor Instrument Ltd., Oxford) in 11 hypertonic and in 14 normotonic pregnant women (+/- proteinuria, +/- pathologic increase in body mass, 16-36 years old, 26-40th week of gestation) with the exception of systolic and diastolic blood pressure, all statistical and clinical criteria were identical in the two groups. There were, however, in the hypertonic patients significant reductions in most of the LD criteria (basal and maximal speed and concentration of erythrocytes, duration of reactive hyperaemia). Regardless of group assignment, there were negative correlations between erythrocytes speed on the one side (basal, maximal), and blood pressure an the other, in some instances also to the increase in body mass and to the APGAR score of newborns. These preliminary findings are considered on an expression of cutaneous vasoconstriction accompanying hypertension in pregnancy. Extensive validation of LD under these conditions seems promising.

Adolescent↗