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Biomedical subjects

D Braun

Publications and source records attributed to D Braun.

At least 55 records · Page 3Linked to original sources
PubMed1997

Post-prandial lipaemia after a moderate fat challenge in normolipidaemic men with and without coronary artery disease.

BACKGROUND: The role of triglycerides as a risk factor for coronary artery disease (CAD) is controversial. In prospective studies, which have reported discrepant results, triglycerides have generally been measured with subjects in the fasting state. Taking into account the fact that the average person spends up to 18 h per day in the post-prandial state, fasting triglyceride levels alone are inadequate to describe the actual effective concentrations, metabolism and atherogenicity of triglyceride-rich lipoproteins. Therefore, investigations of the dynamic post-prandial triglyceride metabolism of patients with CAD in comparison with healthy controls are necessary. METHODS: We studied the post-prandial metabolism of lipids in 99 men: 50 male patients with CAD confirmed by angiography and 49 matched healthy men. After an overnight fast of 12 h, the subjects (aged 40-60 years) ate a standardized oral fat load (3.2 MJ; 49 g fat = 58% of the total energy content). Blood samples for lipid analyses were drawn immediately prior to and hourly during the 6 h period after ingestion of the meal. RESULTS: As required by the study design, fasting triglyceride and total cholesterol levels did not differ between patients and controls; however, high-density lipoprotein (HDL), HDL2 and HDL3 cholesterol levels were significantly lower in the CAD patients. The highest post-prandial triglyceride serum concentrations were observed 3 h after ingestion of the oral fat load both in cases and in controls. Generally, CAD patients had slightly higher triglyceride values than did controls and, at the 5 h measurement point, this difference was significant. CONCLUSIONS: The results suggest that there are differences in triglyceride metabolism between patients with CAD and healthy controls after a challenge with a moderate amount of fat. These differences can best be observed in the degradation phase of post-prandial lipaemia.

Adult↗
PubMed1996

Stationary and pursuit visual fixation share similar behavior.

Stationary and pursuit fixation may involve different fixation mechanisms that are reflected by differences in saccadic reaction times (SRTs). Gap, Simultaneous, and Overlap interval paradigms provided three distinct SRT ranges for comparisons between these two viewing conditions. SRTs following pursuit fixation were longer than following stationary fixation, but were similarly affected by the interval paradigms. The SRT increase with smooth pursuit was largely explained by additional demands for programming oblique saccades. The paradigm dependent SRT relationships also persisted after timing cues were minimized. These results indicate that stationary and pursuit fixation have similar responses to different fixation paradigms and do not implicate the existence of multiple fixation processes.

Analysis of Variance↗
PubMed1995

The enhancement of muscimol-stimulated 36C1 influx by the antispastic 5-aryl-3-(alkylsulfonyl)-4H-1,2,4-triazole (MDL 27,531) in rat brain membrane vesicles.

The antispastic triazole, 4-methyl-3-methylsulphonyl-5-phenyl-4H-1,2,4-triazole (MDL 27,531) was tested in glycine- and muscimol-stimulated 36Cl- influx into brain membrane preparations. MDL 27,531 (100 nM) had no effect on glycine- (100 nM-400 microM) stimulated 36Cl- influx in brain stem tissue; on the other hand, MDL 27,531 (10 nM-10 microM) enhanced muscimol- (1 microM) stimulated 36Cl- influx in cerebellar but not cortical membranes. In the presence of the benzodiazepine (BZD) antagonist, flumazenil (10 microM), MDL 27,531 inhibited muscimol-stimulated flux. These data suggest a novel interaction of this triazole with subtypes of the gamma-aminobutyric acid (GABA)A receptor complex and the BZD receptor.

Animals↗
PubMed1995

New butenolides from the photoconductivity screening of Streptomyces antibioticus (Waksman and Woodruff) Waksman and Henrici 1948.

Streptomyces antibioticus strain TU 99, from which a wide variety of active compounds had been isolated previously, was reinvestigated using an HPLC photoconductivity screening system. Four new compounds were isolated, characterized and their constitutions determined. All four were alpha, beta-unsaturated gamma-lactones; the most abundant compound 3 (C10H16O4), as well as compound 1 (C9H14O4) had a hydroxy group at C(5) of the lactone ring. The four lactones showed antibiotic activity against Pseudomonas aeruginosa and also a weak inhibition of the chitinase from Serratia marcescens.

4-Butyrolactone↗
PubMed1994

Transcranial magnetic stimulation of extrastriate cortex degrades human motion direction discrimination.

The human temporo-parieto-occipital junction is an extrastriate visual area that may mediate motion vision processing. We determined if transcranial magnetic stimulation (TMS) delivered over this extrastriate area would degrade motion discrimination, similar to the transient decrease in spatial acuity observed when TMS is delivered over striate cortex. TMS was delivered 50-250 msec after the onset of a brief, random dot, motion direction discrimination task or a spatial acuity task. TMS significantly reduced correct motion discrimination when delivered 100-150 msec after the random dot stimulus. During the same time window TMS did not significantly effect spatial acuity. TMS over the left extrastriate cortex reduced motion discrimination in both hemifields and its effect had a crude topographical organization. TMS safely perturbs extrastriate visual areas and may reveal the temporal sequence of higher perceptual processing.

Adolescent↗
PubMed1994

Hearing smiles and frowns in normal and whisper registers.

Two experiments measured listeners' abilities to detect facial expression in unfamiliar speech in normal and whisper registers. Acoustic differences between speech produced with neutral or marked facial expression were also assessed. Experiment 1 showed that in a forced-choice identification task, listeners could accurately select frowned speech as such, and neutral speech as happier sounding than frowned speech in the same speakers. Listeners were able to judge frowning in the same speakers' whispered speech. Relative to neutral speech, frowning lowers formant frequencies and increases syllable duration. In both registers, judgments of frowning and its relative happiness were significantly poorer for lip-rounded vowels, suggesting that listeners may recover lip protrusion in making judgments. Experiment 2 replicated the finding [V. Tartter, Percept. Psychophys. 27, 24-27 (1980)] that listeners can select speech produced with a smile as happier sounding than neutral speech in normal register, and extended the findings to whisper register. Relative to neutral, smiling increased second formant frequency. Results are discussed with respect to nonverbal auditory emotion prototypes and with respect to the direct realist theory of speech perception.

Emotions↗
PubMed1994

[Muscle aches and biochemical changes following a ultra-marathon in the cold--modification by diclofenac].

After the Swiss Alpine Marathon in Davos (67 km, altitude difference of 2300 m) the majority of the athletes are suffering from muscle soreness. The goal of the study was therefore to investigate muscle damage, inflammatory reactions and soreness perception during and after this ultramarathon. 27 athletes took part in the study. Creatine-kinase (CK) and C-reactive protein (CRP) were measured 24 hours before the race, immediately before and after the race as well as 2 hours, 24 hours and 48 hours, after the race respectively. Muscle soreness of the lower extremities before and during stretching were assessed at the same time points using a visual analog scale from 1 to 10 (VAS). Significant CK elevations were found in all runners ranging from 600 to 28,000 U/l. Compared to the values before and 48 hours after the start all athletes showed 24 hours after the start significantly elevated CRP values, indicating a pronounced systemic inflammatory reaction. Immediately after the race all runners reported a significantly elevated muscle soreness with maximal pain in the posterior muscles of the lower leg. In order to assess the influence of a nonsteroidal antiinflammatory agent on muscle damage, muscle soreness and inflammatory reactions 16 of the 27 runners received *Diclofenac SR. We were unable to find a difference in the mean plasma CK and CRP activity after the race between both groups, but there was a highly significant, till now to our knowledge never described correlation between the degree of muscle damage and systemic inflammatory reaction (r = 0.75, p < 0.02) in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Accidental head trauma and retinal hemorrhage.

Retinal hemorrhage and intracranial hemorrhage in a child with little external evidence of trauma and with a poorly documented history are considered pathognomonic child abuse. The mechanism and magnitude of force required to produce the injuries are seldom witnessed or known. This study was designed to determine the incidence of retinal hemorrhage in pediatric head injuries under known accidental circumstances, in association with forces sufficient to cause skull fracture and/or intracranial hemorrhage. Of 525 consecutive hospital admissions for head injuries, 200 children filled these criteria. Thirty children were excluded because of suspected child abuse or gunshot wounds. Of the remaining 170, 140 were evaluated by an ophthalmologist for retinal hemorrhage. Two children, who were both involved in side-impact car accidents, had retinal hemorrhages in associated with severe head injury. Retinal hemorrhage occurs rarely in accidental head injury and is associated with extraordinary force.

Accidents↗
PubMed1992

[Effect of carbohydrate intake during a long distance run on work capacity and metabolism].

The present study addressed the effects of carbohydrate consumption during endurance exercise on performance, energy turnover, and metabolism. Well-trained endurance runners consumed a beverage with (cho[+]) or without (cho[-]) carbohydrates during a long-distance run (46.6 km). The respiratory quotient (RQ), plasma levels of carbohydrate and fat metabolites, and of hormones (insulin, glucagon) were measured before, several times during, and after the run. The mean running speed for the entire distance was 13.6 and 13.4 km/h with the cho[+] and cho[-] beverage, respectively. The decrease in speed that was observed towards the end of the run was somewhat more pronounced with consumption of the cho[-] beverage. The RQ decreased during the run almost linearly. This decrease was independent of the consumed beverage. The changes in plasma levels of lactate, free fatty acids (FFA), glycerol, D-3-hydroxybutyrate (DHB), glucagon and insulin that occurred during the run were not affected by intake of the cho[+] beverage. However, intake of the cho[+] beverage prevented the decrease in plasma glucose observed towards the end of the run under control conditions, and eliminated the steep postexercise increase in plasma DHB. The intake of the cho[+] beverage also caused a rapid decrease in plasma levels of FFA and glucagon after the run, and slightly increased plasma insulin. The results demonstrate that ingestion of a carbohydrate-containing beverage during a long-distance run affects metabolism only during the final phase of the run and during the subsequent recovery period. Moreover, carbohydrate consumption improves performance only during the final phase of a long-distance run.

3-Hydroxybutyric Acid↗
PubMed1992

Saccadic reaction times in patients with frontal and parietal lesions.

The effect of unilateral circumscribed lesions in different areas of the frontal and parietal cortex on the distributions of saccadic reaction times (SRTs) was investigated in 32 patients under four stimulus conditions: (i) gap-random: a target light appeared 200 ms after extinction of a central fixation light randomly at 8 degrees either left or right; (ii) overlap-random: like (i), but the fixation light remained on ('overlap'); (iii) gap-simultaneous: two peripheral lights appeared simultaneously left and right 200 ms after the extinction of the fixation light, one predesignated by instruction as saccadic target; (iv) overlap-simultaneous: like (iii), but the fixation light remained on. Depending on SRT and condition and based on the data of control subjects, we evaluated the percentages of anticipatory (SRT: 0-90 ms), express (91-157 ms) and regular (158-400 ms) saccades, of time (> 400 ms) and direction errors as well as the mean latencies and the standard deviations. These data were compared across control subjects, frontal lobe patients with a lesion in the region of the frontal eye field (FEF), and frontal patients with a lesion outside the FEF, as well as across control subjects, parietal lobe patients with a lesion in the dorsolateral region, and parietal patients with a lesion outside the dorsolateral region. (i) Frontal patients with a lesion in the FEF region showed an increased percentage of express saccades (gap-random condition), especially with saccades directed towards the side of the lesion (ipsilateral). If fixation was not interrupted prior to target appearance (overlap-random), express saccades were largely suppressed, similar to normals. All patients with a frontal lesion, whether in the region of the FEF or not, showed a decreased percentage of contralateral anticipatory saccades (gap-simultaneous), whereas the percentages of direction and time errors were in the normal range, even if more than one stimulus was presented (e.g. overlap-simultaneous condition). (ii) Patients with dorsolateral parietal lesions showed decomposed SRT patterns (high SRT variability, increased percentages of time and direction errors, decreased percentages of express and anticipatory saccades). The decomposition had a contralateral preponderance and increased if more than one stimulus was visible beside the saccadic target. Our results suggest that FEF lesions impair mainly the volitional control over visually triggered express or reflex-like saccades if fixation is disrupted, whereas dorsolateral parietal lesions impair mainly the selection of the visual targets.

Adult↗