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Biomedical subjects

R Frey

Publications and source records attributed to R Frey.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Myo-inositol in depressive and healthy subjects determined by frontal 1H-magnetic resonance spectroscopy at 1.5 tesla.

Myo-inositol (mI) as a precursor in the phosphatidylinositol second messenger system has been reported to be reduced in depression. By means of proton-magnetic resonance spectroscopy (1H-MRS) the mI levels in the frontal brain were investigated in vivo in the present study. Twenty-two patients (mean age: 42.8 +/- 10.7 years) with depressive episodes according to ICD 10 (HAMD score > 17) were compared to 22 healthy subjects (28.0 +/- 5.3 years). Two voxels (30 x 20 x 20 mm3) in the frontal lobes were examined in a Siemens Magnetom SP 4000 at 1.5 T (STEAM sequence: TR = 3500 ms, TE = 55 ms). With the total creatine (Cr) as an internal standard, mI/Cr ratios were calculated to follow the mI levels. In the left frontal lobe, mI/Cr was 0.43 +/- 0.06 in depressive patients and 0.46 +/- 0.07 in healthy subjects; concerning the right frontal lobe, mI/Cr was 0.46 +/- 0.08 and 0.48 +/- 0.06, respectively. There were neither significant differences between the two groups nor between the hemispheres. Since there was a significant positive correlation (R = 0.6) between the age and the mI/Cr in the right frontal lobe of depressed patients, age matched pairs analysis was performed (n = 2 x 10, in each group: nine females, one male, < 40 years). In the right frontal lobe, the patients' mI/Cr of 0.40 +/- 0.05 was now significantly lower than the controls' mI/Cr of 0.45 +/- 0.06. However, most of the patients were on antidepressive medication. Interestingly, it was exactly this group of patients which showed significantly lower mI levels. We regard our investigation as a pilot study which suggests an influence of age and antidepressants on mI levels and should be taken into consideration in further investigations in depressive patients.

Adult↗
PubMedDate not supplied

[Short-term-interval stress following corrective operations in tetralogy of Fallot].

21 clinically asymptomatic children aged 5.5 to 15.5 years were examined by bicycle exercise 1 to 9 years after surgical repair for tetralogy of Fallot. The results were compared to normal values gained from 169 healthy children (10 age groups of girls and boys). Submaximal exercise testing was performed in three stages of 1, 2 and 3 Watts per kg body weight, followed by 2 minutes of recovery. The following results were gained: 7 of the 21 patients showed rhythm disturbances during the exercise testing. Only three of them had documented arrhythmias before this date. Another 3 children with normal exercise test had arrhythmias in their former history. Thus total incidence of documented arrhythmias is 48 percent in contrast to only 1.2 percent in the control group. Using this weight related exercise test the heart rates of the patients were significantly lower during exercise than those of the control group. The differences are most evident during the maximal exercise period. The ability of LVET-shortening with increasing heart rates was significantly reduced in the patients. PEP was significantly prolonged. Both phenomena lead to a relatively shorter diastole than in normal subjects. This must result in a hemodynamical disturbance under the conditions of high frequencies. Blood pressure monitoring is not very valuable for the interpretation of hemodynamic changes. There are signs of alterations of hemodynamics as well as of the heart rhythm in the patients after surgical repair for the tetralogy of Fallot, even if the patients feel very well. By short time submaximal exercise testing it is possible to detect these alterations.

Adolescent↗