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Michael Bauer

Publications and source records attributed to Michael Bauer.

At least 73 records · Page 4Linked to original sources
PubMed2004

Using technology to improve longitudinal studies: self-reporting with ChronoRecord in bipolar disorder.

OBJECTIVES: Longitudinal studies are an optimal approach to investigating the highly variable course and outcome associated with bipolar disorder, but are expensive and often have missing data. This study validates patient self-reported mood ratings using a home computer-based system (ChronoRecord) with clinician mood ratings on the Hamilton Depression Rating scale (HAMD) and Young Mania Rating scale (YMRS), and investigates the patient acceptance of the technology. METHODS: After brief training, outpatients with bipolar disorder were given the software version of an established paper based self-reporting form (ChronoSheet) to install on a home computer. Every day for 3 months, patients entered mood, medications, sleep, life events, and menstrual data. Weight was entered weekly. RESULTS: Eighty of 96 (83%) patients returned 8662 days of data. The mean days of data returned was 114.7 +/- 32.3 SD The mean percentage of days missing for mood data was 6.1% +/- 9.3 SD, equivalent to missing 7.3 day of the 114.7 days. Self-reported ratings were strongly correlated with clinician HAMD ratings (-0.683, p < 0.001). CONCLUSIONS: This study demonstrates concurrent validity between ChronoRecord and HAMD. Patients with bipolar disorder showed high acceptance of a computer-based system for self-reporting of daily data. Automation of data collection can reduce missing data and eliminate errors associated with data entry. This technology also enables on-going feedback for both patient and researcher during a long-term study.

Adult↗
PubMed2004

Impact of bispectral index monitoring on stress response and propofol consumption in patients undergoing coronary artery bypass surgery.

BACKGROUND: Bispectral Index (BIS)-titrated administration allows a reduction of propofol infusion rates in patients undergoing surgery. Resulting differences in anesthetic depth might affect the stress response to surgery involving neural circuitry not reflected in the electroencephalogram. METHODS: Forty patients scheduled to undergo elective coronary artery bypass grafting receiving a background infusion of remifentanil (0.3 microg . kg . min) were anesthetized with intravenous propofol delivered by target-controlled infusion according to the Marsh pharmacokinetic model under BIS monitoring. In a randomized, prospective design, 20 patients received propofol at a target concentration of 3 microg/ml, whereas in 20 patients propofol was titrated to maintain a BIS value of 40-50. Plasma concentrations of propofol (by means of gas chromatography-mass spectrometry), epinephrine, norepinephrine (by means of high-pressure liquid chromatography), cortisol (by means of radioimmunoassay), and interleukins 6 and 10 (by means of enzyme-linked immunosorbent assay) were measured repeatedly throughout surgery. RESULTS: BIS monitoring allowed a 30% reduction of propofol infusion rates and a similar decrease in plasma propofol concentrations in the BIS group without affecting the stress response to surgery for the group mean. None of the patients reported awareness during a standardized interview. Interestingly, propofol-remifentanil anesthesia blunted the release of epinephrine and cortisol to bypass surgery completely even when the propofol infusion rate was reduced according to BIS values. CONCLUSIONS: Total intravenous anesthesia using propofol-remifentanil effectively attenuates the neurohumoral stress response to coronary bypass surgery involving cardiopulmonary bypass. Titration of propofol using BIS allows for significant reduction of propofol consumption, with only minor effects on stress response under these conditions.

Aged↗
PubMed2004

Heme oxygenase-1 gene expression in pericentral hepatocytes through beta1-adrenoceptor stimulation.

Induction of heme oxygenase (HO)-1 may confer hepatocellular protection, e.g., in reperfusion injury. Previous reports suggest that intracellular cAMP up-regulates HO-1. The aim of the present study was to assess the role of adrenoceptor agonists as a means to induce HO-1 and to assess molecular mechanisms of HO-1 gene expression by adrenoceptor agonists. Induction of HO-1 in primary cultures of hepatocytes and in rat liver in vivo was assessed by Northern blot, Western blot, and immunohistochemistry. The beta-receptor agonists (+/-)isoproterenol and (-)isoproterenol induced HO-1 in primary cultures of hepatocytes but not the inactive enantiomer (+)isoproterenol. No induction of HO-1 was observed after alpha1, alpha2, beta2, or beta 3 agonists. beta1-Receptor agonists dobutamine and xamoterol induced HO-1 dose dependently, whereas the beta1-receptor antagonist metoprolol attenuated HO-1 induction by beta1-receptor agonists. Furthermore, 8 Br-cAMP and forskolin induced HO-1. Inhibition of protein kinase A (PKA) abolished induction by dobutamine and 8 Br-cAMP. Parallel changes were observed for the transcription factor AP-1. In vivo infusion of dobutamine for 6 h induced HO-1 in rat livers. Immunohistochemical detection of HO-1 revealed a pericentral expression pattern of HO-1 in hepatocytes, i.e., the area at risk for ischemia/reperfusion injury. These results suggest induction of HO-1 by beta1-adrenoceptor agonists via the PKA pathway in hepatocytes, reflecting a potential means for "pharmacological preconditioning."

Adrenergic Agonists↗
PubMed2004

Peptidoglycan of Staphylococcus aureus causes inflammation and organ injury in the rat.

OBJECTIVE: Previous studies have implicated a role of peptidoglycan in the pathophysiology of organ injury in sepsis. However, the systemic response to, and organ injury caused by, peptidoglycan have been scarcely studied in vivo. DESIGN: Prospective, randomized study. SETTING: University-based research laboratory. SUBJECTS: Fifty-seven anesthetized, male Wistar rats. INTERVENTIONS: After surgical preparation, anaesthetized rats were administered 3 mg/kg Staphylococcus aureus peptidoglycan (n = 9), 10 mg/kg S. aureus peptidoglycan (n = 14), or an equal volume of saline (sham, n = 12) in the jugular vein over a 10-min period. MEASUREMENTS AND MAIN RESULTS: Injection of low-dose peptidoglycan (3 mg/kg) had no measurable effects on the rats. In contrast, high-dose peptidoglycan (10 mg/kg) caused increased serum values of aspartate aminotransferase (p < or =.005), alanine aminotransferase (p < or =.001), gamma-glutamyltransferase, and bilirubin (p < or =.05) (indicators of liver injury/dysfunction) as well as a moderate, but significant, increase in serum creatinine and urea (p < or =.05) (indicators of renal dysfunction). Plasma analyses showed a substantial increase in plasma values of tumor necrosis factor-alpha, interleukin-6, and interleukin-10 (p < or =.05 for all vs. sham) at 1 and 3 hrs (enzyme-linked immunosorbent assay). This was accompanied by accumulation of messenger RNAs for tumor necrosis factor-alpha, interleukin-6, and interleukin-10 in both the liver and the lung (p < or =.05 for all cytokines vs. sham) (real-time polymerase chain reaction). Peptidoglycan also caused increased DNA binding of nuclear factor-kappaB (band-shift assays) and phosphorylation of c-Jun and Jun N-terminal kinase (Western blots). In the kidney, interleukin-6 messenger RNA was increased, whereas Toll-like receptor 4 messenger RNA was significantly decreased. CONCLUSIONS: These results demonstrate that injection of peptidoglycan alone causes organ injury/dysfunction, organ inflammation, and systemic inflammation in the rat, involving nuclear factor-kappaB and possibly activator protein 1. These data support the contention that peptidoglycan is a contributing factor in the pathophysiology of organ injury in sepsis.

Animals↗
PubMed2004

Hepatocyte growth factor and c-Met expression in rat and human liver fibrosis.

BACKGROUND: Hepatocyte growth factor (HGF) is a potent mitogen for hepatocytes in vitro. AIMS: Substitution of HGF was suggested for human liver disease on the basis of animal experiments. The cellular sources of HGF and its receptor, c-Met, in liver disease in vivo are not well defined. METHODS: We characterised HGF and c-Met expression in normal and cirrhotic human livers and rat livers at various time points after CCl4 administration by in situ hybridisation and immunohistology. HGF transcripts were restricted to resting and activated stellate cells in rat and human liver. RESULTS: In rat liver, HGF showed peak levels 6-12 h following acute intoxication, and remained increased after repeated CCl4 injury. HGF transcript levels were very low in normal human liver, but excessively raised in fibrosis/cirrhosis. In contrast, HGF immunoreactivity was found not only in perisinusoidal/periductular cells but also in cholangiocytes of proliferating ductules. c-Met RNA and protein was expressed in hepatocytes, cholangiocytes, and arteriolar endothelial cells. CONCLUSIONS: The HGF-specific immunostaining of proliferating cholangioles in the absence of HGF RNA suggests c-Met-mediated uptake of HGF and paracrine stimulation of cholangiocellular proliferation. Mitogenic effects of HGF on hepatocytes may therefore be accompanied by undesired cholangiogenesis and angiogenesis limiting its therapeutic value in chronic liver disease.

Animals↗
PubMed2004

Cytokine response to pulmonary thromboendarterectomy.

BACKGROUND: Pulmonary thromboendarterectomy (PTE) is an effective but challenging treatment for chronic thromboembolic pulmonary hypertension (CTEPH). PTE is associated with marked hemodynamic instability in the perioperative course, suggesting the involvement of circulating mediators. The aim of this study was to characterize the expression of proinflammatory and anti-inflammatory cytokines in patients undergoing PTE. METHODS: Fourteen patients with CTEPH (mean [+/- SD] pulmonary vascular resistance, 1,056 +/- 399 dyne.s.cm(-5)) underwent PTE using cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA). Peripheral arterial blood samples were drawn prior to patients undergoing sternotomy, during CPB, before and after DHCA, and 0, 8, 16, 24, and 48 h after surgery. An enzyme-linked-immunosorbent assay was used to analyze the plasma levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-10. Seven patients undergoing aortic arch replacement (ARCH) in DHCA served as a control group. RESULTS: Prior to and during PTE, the CTEPH patients exhibited elevated TNF-alpha levels, which decreased within the first 24 postoperative hours (p = 0.02). There was no TNF-alpha release among patients in the ARCH group. IL-6 levels were similar in both groups throughout the perioperative course. A profound anti-inflammatory response was observed in the PTE group, which was reflected by elevated IL-10 levels prior to surgery and a marked peak level immediately after surgery. A positive correlation was found between maximum vasopressor support and peak levels of IL-6 (r = 0.82) in the PTE patients. CONCLUSION: Heart failure due to CTEPH appears to generate a pronounced inflammatory response with the release of proinflammatory and anti-inflammatory cytokines. PTE results in the rapid normalization of preoperatively elevated TNF-alpha levels. IL-6-mediated systemic inflammatory cascades may be involved in the regulation of peripheral vascular tone after PTE.

Cardiopulmonary Bypass↗
PubMed2004

Peripheral thyroid hormones and response to selective serotonin reuptake inhibitors.

OBJECTIVE: To examine the relation between baseline measurements of thyroid function and response to selective serotonin reuptake inhibitors (SSRIs) and to consider the effect of these antidepressants on thyroid hormone levels. METHODS: Nineteen subjects with major depression, but without a history of thyroid treatment or lithium treatment, were treated openly with either sertraline or fluoxetine in a university- affiliated tertiary care hospital. Hamilton Depression Rating Scale (Ham-D) scores were measured before and after treatment. Clinical Global Impressions (CGI) scores were measured at study end. Thyroid data, consisting of values for thyroid-stimulating hormone (TSH), triiodothyronine (T(3), measured by radioimmunoassay [RIA]), thyroxine (T(4), measured by RIA) and free T(4), were collected before and after treatment. Complete thyroid data were available for 17 subjects. Data were collected during 1997-1999. RESULTS: Baseline TSH correlated strongly with response to treatment as measured by change in Ham-D scores (r = 0.64, p = 0.003). Low TSH values correlated with greater improvement in depressive symptoms. Thyroid hormone levels decreased with treatment, but these decreases did not correlate with clinical improvement. CONCLUSION: Baseline thyroid function, as measured by serum TSH, may predict a patient's response to antidepressant treatment with SSRIs. Optimal thyroid function, beyond simply being within the normal laboratory values, may be necessary for an optimal response to antidepressants.

Adolescent↗
PubMed2004

Noninvasive mechanical ventilation of mice by using a balloon-tipped cannula.

Cardiovascular research in mouse models can lead to respiratory insufficiency with the need for temporary mechanical ventilation to reduce mortality. We developed a noninvasive method for brief ventilation in which a balloon-tipped cannula is inserted into the oral cavity of the mouse. The rubber balloon is constructed in such a way that it becomes inflated when the pressure in the tube rises. We tested the cannula in ten C57BL/6J mice which underwent mechanical ventilation by a membrane-pump-driven ventilator. Results of blood gas analyses in the ten cannulated animals were in the normal range after 1 h of mechanical ventilation and did not differ significantly from those of anesthetized and spontaneously breathing mice (n = 5) and mice mechanically ventilated via tracheal intubation (n = 5). Noninvasive mechanical ventilation by using the balloon-tipped cannula is a useful method which is quick and easy to manipulate.

Animals↗
PubMed2003

Thyroid hypofunction in patients with rapid-cycling bipolar disorder after lithium challenge.

BACKGROUND: There is debate whether patients with rapid-cycling bipolar disorder (BD) are predisposed to thyroid axis abnormalities and whether this may contribute to development of rapid mood shifts. Using lithium carbonate as a challenge to the hypothalamic-pituitary-thyroid (HPT) system, we determined whether patients with rapid-cycling BD are sensitive to the "antithyroid" properties of lithium. METHODS: We studied the response to thyrotropin-releasing hormone (TRH) of HPT system hormones in 20 medication-free patients with rapid-cycling BD and compared these measurements with those of 20 healthy age- and gender-matched control subjects. The same measurements were repeated after both groups had received lithium carbonate for 4 weeks in sufficient doses to maintain blood levels between.7-1.2 mEq/L. RESULTS: At baseline, the results of thyroid function tests, including the TRH challenge test, did not differ between patients and control subjects. After treatment with lithium, serum concentrations of thyroxine significantly decreased, whereas basal thyrotropin (TSH) and DeltaTSH(max) significantly increased in both patients and control subjects; however, patients had significantly higher DeltaTSH(max) after TRH stimulation. More patients than control subjects developed laboratory evidence consistent with grade III hypothyroidism after lithium treatment. CONCLUSIONS: Rapid-cycling BD is associated with a latent hypofunction of the HPT system. This dysfunction becomes manifest with short-term lithium challenge.

Adult↗
PubMed2003

Arabidopsis sulfurtransferases: investigation of their function during senescence and in cyanide detoxification.

Sulfurtransferases (STs) and beta-cyano- l-alanine synthase (CAS) are suggested to be involved in cyanide detoxification. Therefore, the accumulation of ST1 and CAS RNAs, and the ST and CAS protein levels and enzyme activities were determined in Arabidopsis thaliana Heynh. plants grown under different conditions. Senescence-associated processes were successfully induced by natural aging, by jasmonate methyl ester and by darkness in whole plants and detached leaves, as demonstrated by the expression of the senescence marker genes SAG12 and SAG13. However, the changes in RNA accumulation and protein levels of ST and CAS did not correlate with the expression of these senescence marker genes; the specific ST and CAS activities either decreased (ST) or increased (CAS). In another experiment, Arabidopsis plants were sprayed with cyanide to investigate the role of ST and CAS in cyanide detoxification. The expression of ST and CAS at the RNA and protein levels, and also the enzyme activities, remained equal in cyanide-treated and control plants. Incubation with 1-aminocyclopropane-1-carboxylic acid, the precursor of ethylene, increased while fumigation with ethylene decreased expression and activity of ST and CAS. In summary, cyanide does not induce the expression or enhance the activity of ST and CAS in Arabidopsis. For both proteins the evidence for a role in cyanide detoxification or induced senescence is low.

Acetates↗
PubMed2003

Lithium augmentation increases post-dexamethasone cortisol in the dexamethasone suppression test in unipolar major depression.

Although considerable evidence exists on the efficacy of lithium as an augmenting agent in refractory depression, the underlying neurobiology of this phenomenon is unknown. In patients with major depression, changes of the hypothalamic-pituitary-adrenocortical (HPA) system have been detected by means of the dexamethasone suppression test (DST), when administered during treatment with tricyclic antidepressants. We investigated whether the DST also reveals alterations of the HPA system during lithium augmentation. We also sought to identify whether response to lithium augmentation can be predicted with the DST. Twenty-five patients with unipolar major depression, who did not respond to an adequate antidepressant monotherapy of at least 4 weeks, were measured for basal (pre-dexamethasone, 0800h) cortisol and ACTH levels and were administered the DST the day before initiation of lithium augmentation treatment. The same neuroendocrine procedures were repeated after 3 to 4 weeks. Criteria of response to lithium augmentation, defined as a reduction of the Hamilton Depression Rating Scale (HDRS17) score by > or =50% and an end point score of 9 or less, were determined by weekly HDRS ratings. The DST revealed a statistically significant increase of the post-dexamethasone cortisol values (P = 0.021) and an increase in the post-dexamethasone ACTH values (P = 0.051) during lithium augmentation as compared to pre-treatment baseline evaluations. The pre-dexamethasone hormone values were unchanged. The number of non-suppressors at baseline was one and increased to three at follow-up. Results of DST did not predict response to lithium augmentation, which occurred in 40% of subjects. Results suggest that lithium augmentation increases HPA system activity, as indicated by the increase of post-dexamethasone cortisol and ACTH levels measured by the DST. This is in contrast to the established decline of HPA system activity during treatment with tricyclic antidepressants.

Adolescent↗
PubMed2003

Lithium augmentation therapy in refractory depression-update 2002.

Lithium has been used to augment the efficacy of antidepressant medications for more than 20 years. The present study examines whether evidence exists to support the clinical efficacy of lithium augmentation in refractory, treatment resistant depression. Studies were identified by searching Medline (1980 to August 2002) and by scanning the references of published reviews and standard textbooks. Studies were selected if they were open-labeled or double-blind, placebo-controlled or comparator trials that involved patients who had not responded to conventional antidepressants. 27 prospective studies were identified that included a total of 803 depressed patients displaying the following designs: 10 double-blind, placebo-controlled trials, 2 randomized, double-blind comparator trials, 2 randomized, open comparator trials, and 13 open-label trials. The majority of randomized controlled trials has demonstrated substantial efficacy of lithium augmentation in partial and non responders to antidepressant treatment. In the placebo-controlled trials, the response rate in the lithium group was 45% and in the placebo group 18% (p<0.001). Summarizing all open and controlled studies, approximately 50% of patients responded to lithium augmentation within 4 weeks. In conclusion, lithium is the foremost and most well-documented augmentation strategy in refractory depression.Therefore, it should be considered a first-line treatment strategy in patients with major depression who do not adequately respond to standard antidepressants.

Adult↗
PubMed2003

Neuronal injury regulates fractalkine: relevance for HIV-1 associated dementia.

Fractalkine (FKN), a chemokine highly expressed in the central nervous system, participates in inflammatory responses operative in many brain disorders including HIV-1 associated dementia (HAD). In this report, HIV-1 progeny virions and pro-inflammatory products led to FKN production associated with neuronal injury and apoptosis. FKN was produced by neurons and astrocytes; but differentially produced by the two cell types. Laboratory tests paralleled those in infected people where cerebrospinal fluid FKN levels in HIV-1 infected cognitively impaired (n=16) patients were found to be increased when compared to infected patients without cognitive impairment (n=8, P=0.0345). These results demonstrate a possible role of FKN in HAD pathogenesis.

AIDS Dementia Complex↗
PubMed2003

Iloprost ameliorates post-ischemic lung reperfusion injury and maintains an appropriate pulmonary ET-1 balance.

BACKGROUND: Ischemia-reperfusion (I/R) injury of the lung involves increased pulmonary vascular resistance. Prostaglandins are thought to have a beneficial effect in lung transplantation, but their mechanism in I/R injury is unknown. We investigated whether iloprost, a stable prostacyclin analogue, prevents I/R-associated pulmonary vascular dysfunction and whether it affects endothelin-1 (ET-1) balance. METHODS: In an isolated blood-perfusion model, we subjected lungs of Lewis rats to 45 minutes of ischemia at 37 degrees C and randomly allocated the lungs to 3 groups (n = 6 each): iloprost (33.3 nmol/liter) added to the perfusate before ischemia and reperfusion (ILO+IR), iloprost (33.3 nmol/liter) given only before reperfusion (ILO+R), and controls without iloprost treatment (ILO-). RESULTS: Reperfusion induced marked pulmonary edema in non-treated controls (ILO-), which was attenuated in ILO+R lungs and completely prevented in ILO+IR lungs. At 60 minutes reperfusion, arterial oxygen tension was significantly greater in both ILO+R and ILO+IR lungs compared with ILO- controls. Mean pulmonary artery pressure and pulmonary vascular resistance were slightly decreased in the ILO+R and significantly decreased in the ILO+IR group compared with the ILO- controls. Plasma levels of big ET-1, measured in both afferent and efferent blood, showed that I/R results in increased pulmonary venous levels of big ET-1. Interestingly, the increased venoarterial ET-1 gradient in ILO- lungs decreased significantly in the ILO+IR group. CONCLUSIONS: We demonstrated in an isolated lung perfusion model that iloprost ameliorates post-ischemic lung reperfusion injury and maintains an appropriate pulmonary ET-1 balance.

Animals↗
PubMed2003

Menstrual cycle related mood changes in women with bipolar disorder.

OBJECTIVES: A relationship between affective symptoms and menstrual cycle in women with bipolar disorder (BPD) has been suggested. This study investigates the influence of the menstrual cycle on mood in women with BPD who are taking medication, but not selected for menstrual abnormalities. METHODS: Data from women with BPD (n = 17) consecutively enrolled into a ChronoRecord validation study were included in the current analysis. All women received medication for BPD, in addition, 35% received oral contraceptives (OC). Participants entered mood, menstrual data, psychiatric medications, and life events daily for a 3-month period using a computerized version (ChronoRecord) of an established paper based form for self-reporting (ChronoSheet). RESULTS: The majority of women treated for BPD (65%) reported significant mood changes across the menstrual cycle. Long menstrual cycle was present in 59% of subjects, including those taking OC. CONCLUSIONS: Women with BPD taking medication report a high rate of long menstrual cycles, and significant mood changes in relation to menstrual cycle phase.

Adult↗