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Biomedical subjects

U Pfeiffer

Publications and source records attributed to U Pfeiffer.

At least 19 recordsLinked to original sources
PubMed2004

High neuroticism and depressive temperament are associated with dysfunctional regulation of the hypothalamic-pituitary-adrenocortical system in healthy volunteers.

OBJECTIVE: Elevated neuroticism, depressive temperament and dysfunctional regulation of the hypothalamic-pituitary-adrenocortical (HPA) system are considered as risk factors for unipolar depression. An interaction of these vulnerability factors was suggested, but controversially discussed. In absence of other informative studies we set out for a replication test and for elucidation of the underlying mechanism. METHOD: Ninety-two subjects recruited in the community-performed assessments of personality and temperament as well as measurement of HPA function with the dexamethasone/corticotropin-releasing hormone (Dex/CRH) test. RESULTS: Cortisol levels subsequent to Dex/CRH challenge were associated with neuroticism; high-neuroticism subjects revealed a higher HPA activation. This difference was mainly because of male subjects >/=25 years. A similar relationship was observed for depressive temperament. CONCLUSION: This constellation may propose that HPA dysregulation is the endocrinological basis for neuroticism and depressive temperament; this result supports the view that distinct personality factors and HPA vulnerability interact in mediating depression.

Adrenal Cortex Hormones↗
PubMed2003

Early intrauterine exposure to tobacco-inhaled products and obesity.

An association between maternal smoking during pregnancy and offspring obesity has been reported. This study assessed the impact of maternal smoking during the first trimester. Data on 4,974 German children aged 5-6 years were obtained at school entry health examinations in 2001-2002 in Bavaria. Obesity was defined by body mass index using International Obesity Task Force cutpoints. Prevalence of obesity was 1.9% (95% confidence interval (CI): 1.5, 2.4) in offspring of never smokers, 4.5% (95% CI: 2.9, 6.7) for maternal smoking during the first trimester only, and 5.9% (95% CI: 3.8, 8.7) for maternal smoking throughout pregnancy. Unadjusted odds ratios were higher for maternal smoking throughout pregnancy (odds ratio = 3.23, 95% CI: 2.00, 5.21) compared with the first trimester only (odds ratio = 2.41, 95% CI: 1.49, 3.91). Adjusted odds ratios were similar: 1.70 (95% CI: 1.02, 2.87) for maternal smoking throughout pregnancy and 2.22 (95% CI: 1.33, 3.69) for maternal smoking in the first trimester only. When modeled together, no statistically significant difference in obesity risk was found between maternal smoking in the first trimester compared with throughout pregnancy. The effect of intrauterine tobacco exposure on childhood obesity may depend largely on cigarette smoking during the first trimester, whereas the additional impact of smoking throughout pregnancy might be due to confounding by sociodemographics. Women should be encouraged to quit smoking prior to conception.

Adult↗
PubMed2001

Right frontal hypergyria differentiation in affected and unaffected siblings from families multiply affected with schizophrenia: a morphometric mri study.

OBJECTIVE: The authors used magnetic resonance imaging to corroborate the postmortem finding of right frontal hypergyria associated with schizophrenia. METHOD: Twelve affected-unaffected sibling pairs from families multiply affected with schizophrenia were studied. Bilateral measurement of the gyrification index, the ratio of the inner and outer surface contours, was performed on three different slices of the prefrontal region. RESULTS: The mean gyrification index on the right side was significantly higher in siblings with schizophrenia or schizoaffective disorder than in the unaffected siblings. CONCLUSIONS: In this family cohort study, the postmortem finding of right-sided hypergyria in subjects with schizophrenia was replicated in vivo with magnetic resonance imaging. This observation provides further support for a neurodevelopmental mechanism in the pathogenesis of schizophrenia.

Adult↗
PubMed2000

Disturbed gyrification of the prefrontal region in male schizophrenic patients: A morphometric postmortem study.

OBJECTIVE: The goal was to test the hypothesis that abnormalities of gyrification are present in the prefrontal region of postmortem brains from schizophrenic patients. METHOD: The authors compared the prefrontal regions in brains from 24 schizophrenic patients and 24 normal comparison subjects. The gyrification index, the ratio of inner and outer surface contours, was measured bilaterally in three different slices from each brain. Area measurements of gray and white matter were studied separately by planimetric analysis in the same sections. In addition, a gray-to-white-matter ratio and an asymmetry coefficient were computed. RESULTS: The mean gyrification index on the right side was significantly higher in the male schizophrenic patients than in the comparison men. The gyrification index of the female patients was not significantly different from that of the female comparison subjects. Analysis of area measurements revealed no significant differences. CONCLUSIONS: As gyrification is an ontogenetic stable feature unaffected by atrophic processes during aging, the gyrification abnormalities of the prefrontal region provide further evidence of the importance of a neurodevelopmental mechanism in the etiology of schizophrenia, at least in males.

Age Factors↗
PubMed1997

New monitors of intravascular volume: a comparison of arterial pressure waveform analysis and the intrathoracic blood volume.

OBJECTIVE: Two new monitoring techniques, the analysis of arterial pressure waveform during mechanical ventilation and the determination of intrathoracic blood volume, were evaluated for preload assessment in a model of graded hemorrhage. DESIGN: 8 anesthetized dogs bled of 10, 20, and 30% of their blood volume, then retransfused and volume loaded with plasma expander. Central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), cardiac output, parameters of the arterial pressure waveform analysis [systolic pressure variation (SPV) and delta down (dDOWN)], and intrathoracic blood volume (ITBV) were measured at baseline and after each stage of hemorrhage and volume expansion. RESULTS: The stroke volume index decreased significantly from 1.3 +/- 0.4 ml/kg at baseline to 0.7 +/- 0.2 ml/kg at 30% hemorrhage and then increased after retransfusion and volume loading. The changes in the filling pressures during the various stages of hemorrhage were in the range of 1-2 mmHg. CVP decreased from 5.5 +/- 0.9 to 3.1 +/- 1.7 mmHg and PCWP from 8.0 +/- 0.8 to 5.1 +/- 1.2 mmHg at 30% hemorrhage. Both filling pressures responded significantly to retransfusion; PCWP also changed in response to a volume load. SPV and dDOWN (expressed as percent of the systolic blood pressure during a short apnea) increased significantly from 6.7 +/- 1.7 and 5.6 +/- 3.2%, respectively, at baseline, to 9.7 +/- 2.6 and 8.1 +/- 2.9% after 10% blood loss and to 13.1 +/- 3.9 and 11.1 +/- 3.8% after 30% hemorrhage. ITBV decreased significantly from 29.7 +/- 4.5 to 26.8 +/- 5.3 ml/kg after 10% blood loss and to 23.1 +/- 3.0 ml/kg after 30% hemorrhage. ITBV, SPV, and dDOWN responded significantly to retransfusion and volume load. Significant correlations were found between the degree of volume change and dDOWN (r = 0.93), SPV (r = 0.96), ITBV (r = 0.95), CVP (r = 0.82), and PCWP (r = 0.90). CONCLUSIONS: The parameters of arterial pressure waveform analysis (SPV and dDOWN) and ITBV were sensitive estimates of cardiac preload during the early stages of hemorrhage. Measurement of SPV and dDOWN, being both sensitive and relatively noninvasive, has advantages over other methods of preload assessment but is limited to patients on controlled mechanical ventilation. ITBV, which supplies quantitative information about cardiac preload, is more invasive but can also be used in patients who are breathing spontaneously or who are on partial ventilatory support.

Analysis of Variance↗
PubMed1997

Assessment of perioperative glycerol metabolism by stable isotope tracer technique.

The aim of this study was to investigate metabolic changes during and after abdominal hysterectomy with specific regard to glycerol metabolism. Seven otherwise healthy patients with benign uterine myoma were enrolled in this study. Glycerol turnover and hepatic glucose production were measured before and after the operation by using stable-isotope technique ([1,1,2,3,3-2H5]-glycerol, [6,6-2H2]-glucose). Metabolic substrates (glycerol, nonesterified fatty acids, beta-hydroxybutyrate, glucose, lactate) and hormones (insulin, glucagon, cortisol, catecholamines) were determined pre-, intra- and postoperatively. Hysterectomy was associated with an increase of postoperative glycerol turnover from 3.56 +/- 1.28 to 6.46 +/- 2.44 mumol.kg-1.min-1 (P < 0.05). This increment was inversely related to the age of the patients (r = 0.872, P < 0.05). Glycerol concentration tended to increase perioperatively. These changes, however, were not of statistical significance. Hepatic glucose production and glucose plasma levels increased postoperatively from 9.75 +/- 1.61 to 12.79 +/- 1.45 mumol.kg-1.min-1 (P < 0.05) and 4.6 +/- 0.9 to 6.2 +/- 0.9 mmol/L (P < 0.05), respectively. Cortisol and catecholamine levels rose during and after surgery, while insulin and glucagon remained unchanged. The enhanced rate of lipolysis after hysterectomy was not detectable from plasma glycerol levels alone. The results of this study showed that using stable isotope technique allowed a more differentiated look at metabolic pathways than static plasma substrate concentrations, especially under perioperative conditions.

Adult↗
PubMed1996

Influence of vaginal versus abdominal hysterectomy on perioperative glucose metabolism.

The aim of this study was to investigate the metabolic effects of abdominal versus vaginal hysterectomy with specific regard to perioperative glucose metabolism. Fourteen patients received either abdominal (AH, n = 7) or vaginal hysterectomy (VH, n = 7). Hepatic glucose production was measured before and 2.5 h after the operation by stable isotope technique ([6,6-2H2]-glucose). Metabolic substrates (glucose, lactate, nonesterified fatty acids [NEFA], beta-hydroxybutyrate) and hormones (insulin, glucagon, cortisol, catecholamines) were determined pre-, intra-, and postoperatively. VH induced a higher postoperative glucose concentration than the abdominal approach (VH, 148 +/- 25 mg/dL; AH, 111 +/- 16 mg/dL; P < 0.05). Since postoperative enhancement of hepatic glucose production was comparable in both groups, glucose clearance was lower after the vaginal procedure (VH, 1.7 +/- 0.3 mL.kg-1.min-1; AH, 2.1 +/- 0.3 mL.kg-1.min-1; P < 0.05). NEFA, beta-hydroxybutyrate, and catecholamines similarily increased after surgery. Cortisol levels were more increased after VH (VH, 80 +/- 26 micrograms/dL; AH, 37 +/- 14 micrograms/dL; P < 0.001). Lactate, glucagon, and insulin concentrations did not change perioperatively. The more pronounced hyperglycemic response to VH was due to lower peripheral glucose use caused by higher postoperative cortisol values. The mechanisms responsible for this marked cortisol enhancement after the vaginal operation as well as the clinical significance for patients with preexisting impaired carbohydrate tolerance, however, remained unclear and warrant further investigation.

3-Hydroxybutyric Acid↗
PubMed1995

Disturbed planum temporale asymmetry in schizophrenia. A quantitative post-mortem study.

The planum temporale of the temporal cortex was investigated post-mortem in 24 schizophrenic patients and 24 age- and sex-matched control subjects. Schizophrenic patients demonstrated a 20% volume reduction of the left planum temporale (p = 0.032), whereas on the right side, there was a trend for increase in male schizophrenics (+22%, p = 0.17), while in female patients the volume was moderately decreased (-6%, p = 0.74). The mean anterior-posterior diameter of the planum temporale was significantly reduced in the left hemisphere (-20%, p = 0.008), but unchanged on the right side. The asymmetry coefficients (Galaburda et al. (1987) Neuropsychologia 25, 853-868) for the planum temporale cortex volume (p = 0.02) and anterior-posterior diameter (p = 0.002) but not for mean area (p = 0.61) were significantly different between schizophrenics and control subjects. These data support the idea of disturbed cerebral laterality in schizophrenia. The implications of methodology and patient samples are discussed.

Adult↗
PubMed1994

[Does the choice of a reference system modify the analysis of ergospirometric values?].

The importance of the reference system (arbitrary abscissa units) for the analysis of the time courses of cardiopulmonary exercise test indices was assessed. Ten untrained students, 10 athletes, and 10 triathletes performed an exhaustion-limited cycling test. The courses of 20 pulmonary and hemodynamic indices were investigated with respect to the reference systems "heart rate," "relative and absolute oxygen consumption," "power," and a newly developed index "power-duration-product." Most of the significant differences were observed by reference to the power-duration-product. When using the power-duration-product as reference, the courses of eight indices differed significantly between students and triathletes, the courses of five indices between students and athletes, and the course of one index between athletes and triathletes. Since the number of the significant differences between the groups, as well as the courses themselves, depended clearly on the underlying reference system, the choice of the reference system must be considered as an important determinant for the analysis of cardiopulmonary exercise tests.

Adult↗
PubMed1993

Synthesis and pharmacological activity of a series of dihydro-1H-pyrrolo[1,2-a]imidazole-2,5(3H,6H)-diones, a novel class of potent cognition enhancers.

A series of dihydro-1H-pyrrolo[1,2-a]imidazole-2,5(3H,6H)-diones were synthesized. These bicylic derivatives contain both the 2-pyrrolidinone and 4-imidazolidinone nuclei, already recognized as important for cognition enhancing activity. In addition, these structures maintain the backbone of piracetam and oxiracetam with the acetamide side chain restricted in a folded conformation. Their ability to reverse scopolamine-induced amnesia was assessed in a one trial, step-through, passive avoidance paradigm. The main features observed are a potent antiamnestic activity after ip administration (minimal effective dose being between 0.3 and 1 mg/kg ip for most compounds), the presence of a bell-shaped dose-response curve and, generally, a reduction of biological activity after po administration. However, the unsubstituted compound (15, dimiracetam) shows no evidence of a bell-shaped dose-response curve and completely retains activity when given orally, being 10-30 times more potent than the reference drug oxiracetam.

Amnesia↗
PubMed1993

The neuropathology of schizophrenia: past and present.

Historical aspects of neuroanatomical schizophrenia research and recent findings in limbic and basal ganglia structures of schizophrenia are briefly reviewed. Then, results of volume measurements of these brain regions from 26 schizophrenics and 28 controls belonging to our new brain collection are presented. Volumes of the hippocampus, amygdala, stria terminalis and caudate were bilaterally significantly reduced, the internal pallidum showed a trend towards smaller volumes, while brain weight, putamen, nucleus accumbens and external pallidum were unchanged. The results give further evidence of subtle focal brain tissue reductions in schizophrenics. Finally, gaps in our present knowledge in the neuropathology of schizophrenia and some basic problems in this research field are discussed.

Adult↗
PubMed1992

The power-duration product--evaluation of a new reference system for cardiopulmonary exercise testing.

The aim of this study was to assess the discriminatory power of the new reference system, power-duration product (PDP), for the analysis of haemodynamic and metabolic variables derived from cardiopulmonary exercise tests. The PDP was calculated as the cumulative index of the product of power (W) times the duration (minutes) of each individual exercise step. The study comprised 30 healthy male volunteers, who were classified into three groups with respect to their regular physical activity: 10 untrained medical students (students), 10 sprinters and long-jumpers (athletes) and 10 endurance athletes performing triathlon (triathletes). Twenty metabolic and haemodynamic variables were recorded throughout exhaustion-limited cycling ergometry. The data were analysed with respect to five reference systems (heart rate, relative and absolute oxygen consumption/body surface area, power, and PDP). A total of 14 differences between modified time courses of haemodynamic and metabolic variables in the three groups of volunteers were observed by reference to PDP, 12 by reference to relative oxygen consumption/body surface area, 11 by reference to heart rate, 8 by reference to absolute oxygen consumption/body surface area, and 7 by reference to power. When using PDP as the reference, the time courses of 8 parameters differed significantly between students and triathletes, 5 between students and athletes, and 1 between athletes and triathletes. In addition to its discriminatory superiority for the comparison of different groups characterized by different cardiopulmonary training and endurance, it was found that PDP permitted a better characterization of the individually performed exercise than the consideration of power per se.

Adolescent↗
PubMed1992

Loss of sylvian fissure asymmetry in schizophrenia. A quantitative post mortem study.

The sylvian fissure is known to be one of the most asymmetric structures of the human brain. Sylvian fissure length was measured in post-mortem brains of 35 schizophrenic patients and 33 matched non psychiatric control subjects. The schizophrenics showed a significantly reduced length of the left sylvian fissure (-16%, p less than 0.0001) compared to the control subjects, while the right sylvian fissure length was unchanged. Sylvian fissure asymmetry (left/right ratio) was more reduced in male schizophrenics (-24%, p less than 0.001) than in female patients (-16%, p less than 0.03). This finding is consistent with several post-mortem and MRI studies showing left temporal lobe pathology in a significant proportion of patients and may indicate that schizophrenia is a disorder of early neurodevelopment causing impaired cerebral lateralization.

Adult↗
PubMed1991

Wound instillation for postoperative pain relief: a comparison between bupivacaine and saline in patients undergoing aortic surgery.

In a double blind trial 72 patients having elective aortic surgery were randomized to receive either 40 ml of 0.25% bupivacaine or 40 ml of saline through one or two indwelling wound irrigation catheters every four hours over a total of 48 hours. In transverse incisions the two catheters were randomly placed either subcutaneously or in the rectus sheath; in vertical incisions one catheter was placed subcutaneously. Analgesia was assessed by visual analogue score on Postoperative Days 1 and 2 and the number of doses of intramuscular morphine given during the instillation period. Pulmonary function was monitored by forced expiratory volume and peak flow on Postoperative Days 1 to 5; arterial blood gases were monitored preoperatively and Postoperative Day 2. In all parameters evaluated there was no statistically significant difference between the saline (n = 33) or the bupivacaine (n = 37) groups. Site of the catheter in the transverse groups made no difference. Comparing vertical (n = 21) and transverse (n = 49) incisions, the mean visual analogue scores on the first postoperative day were 40 and 29, respectively (p less than 0.05). Wound instillation with bupivacaine neither improves pulmonary function nor reduces morphine requirements when compared to saline. Transverse incisions may be less painful than vertical ones.

Adult↗
PubMed1990

[Use of the halo-gravitation-extension in preoperative preparation in severe scoliosis].

Severe and fixed scoliosis needs a preoperative extension treatment to attain a good result of correction by spondylodesis. Halo-up-extension is a very simple, comfortable and successful method to prepare patients with a severe scoliosis for operation. From January 1981 to July 1989 we carried out the preoperative halo-up-Extension treatment at 45 patients. 39 of them had a severe scoliosis with a cobb-angle of more than 70 degrees. The correction by halo-up-Extension runs on an average of 35% of the total correction.

Adolescent↗
PubMed1990

[The status of discography in determining indications for therapy of intervertebral disk-induced diseases].

During a 6-year period from 1983 to 1989 we performed lumbal discography in 403 disc levels on 144 patients. We used the discography to determine the therapeutic way in patients with chronic back pain. In the greater half it was possible to define the symptomatic level exactly. About 90% the discography was very helpful to get a diagnosis or to plan the therapy. The reproduction of pain with discography is helpful in the assessment of abnormal disc levels. Even today in view of CT and MRI.

Humans↗