To analyze the flow patterns of the left blood chamber of the Baylor total artificial heart (TAH) and to evaluate influences of the inflow valve angle to the flow patterns, flow visualization studies were performed. The inflow valve angle of the left housing was changed by 20 degrees orthogonal to the inflow tube, and comparison studies of the modified and unmodified models were made. For evaluating sectional flow patterns, a laser light was used, the clear transparent housing was scanned segmentally, and flow patterns were recorded on high contrast film for measuring flow velocities. A signal was used that synchronized the timing of the camera shutter to the pusher-plate movement signal. With the modified 20 degree inflow valve direction, there were better closing characteristics of the inflow valve leaflets. At the same time, we could successfully reduce the vortex formation at the inflow port, which may cause thrombus formation. We also have improved the washout during the diastolic phase in not only the bottom area, but in the entire pumping chamber. This flow visualization setup is simple and inexpensive. It is useful not only for validation of global flow patterns, but also for validation of local flow velocities of various blood pumps.

Biomedical Engineering↗

PubMedDate not supplied

MR imaging of large nonferromagnetic metallic implants at 1.5 T.

To evaluate the feasibility of magnetic resonance (MR) imaging in patients with nonferromagnetic metallic implants, we imaged implants in vitro and in 15 patients. Image artifacts both in vitro and in vivo occurred only locally and consisted of image distortions, areas of total signal loss, and lines of high signal intensity. The artifacts were most prominent in areas where the implants exhibited edges or points, but overall image quality was good except for regions lying very close to the implants. The implants themselves appeared as structures without signal in all patients. We conclude that in patients with femoral head prostheses or osteosynthetic plates that are nonferromagnetic MR may be preferable to CT, where beam hardening artifacts usually degrade image quality severely in the entire field of view.

Alloys↗

PubMedDate not supplied

Expression of rabbit Ig allotypes in litters of mothers immunized against a paternal allotype.

Sera of successive littermates of mothers producing anti-allotype antibodies (Ab) were analysed for altered a locus or b locus allotype expression. We measured the allotype concentration in sera of 66 individuals (17 litters) of seven mothers producing anti-a1 Ab, and 63 individuals (15 litters) of seven mothers producing anti-b4 Ab, in an enzyme-linked immunosorbent assay (ELISA). We confirmed that the ability to induce allotype suppression in utero increases with the number of antigen boosts applied to the mother, even though the Ab titre in the maternal serum may be decreased. All individuals of a litter expressed the allotype in about equal concentration. This contrasts the results we obtained when newborn rabbits were injected with anti-allotype antiserum. Injection of the same amount of anti-allotype antiserum into nine offspring of two mothers caused allotype suppression in only five individuals, showing no effect in the others. No suppression was observed when IgG-depleted antiserum was injected into newborn rabbits. As expected, maternal antibodies to a paternal allotype do not affect the Mendelian distribution of the progeny phenotypes.

Animals↗

PubMedDate not supplied

In utero suppression of kappa 2 isotype in homozygous bas/bas rabbits through embryo transfer.

Allotypes of rabbit Ig provide a useful tool for the study of quantitative expression of alternative allelic forms. In the rabbit, maternal Ig is transmitted to the foetus and protects the immunologically immature newborn during several of the first weeks of life. Induced maternal antibodies directed towards a paternally inherited allotype of the offspring can influence the expression of that allotype drastically. Normal Ig level in heterozygous allotype suppressed animals is provided by increased expression of the alternative allele. On the other hand, allotype suppression in homozygous animals leads to increased expression of non-allelic alternative gene products. We quantitatively analysed the expression of bas, a marker on the kappa 2 light chain isotype of the mutant strain Basilea, in homozygous bas/bas rabbits which had been fostered in utero of b4/b6 mothers producing anti-bas. All of the offspring studied expressed the kappa 2 isotype at a very low level at two months of age, and, in some individuals, bas was hardly expressed after 6 to 12 months. A suppressed rabbit, which was immunized to produce auto-antibodies against bas, continued to do so for at least 2.5 years. The long duration of homozygous bas suppression contrasts with homozygous suppression of other allotypes (CL kappa 1 and VHa) which generally lasts for a much shorter period.

Animals↗

PubMedDate not supplied

[Size of the cell nucleus and nucleus-cytoplasm relations in pinealocytes in humans of middle and advanced age].

In the presented light microscope study, the question was examined of whether the size of the nucleus and nucleolus, respectively the nuclear:cytoplasmic ratio of pinealocytes, are changed in different human age groups. We investigated the pineals of 30 to 40-year-old men in comparison with those from patients who were older than 70 years. The investigation was performed with smears of the pineal gland which were stained according to Pappenheim (May-Grünwald and Giemsa method). The results show that the nuclear size of the pinealocytes of the younger men (30 to 40-year-olds) is 92 micron 2 and is significantly larger than in the older patients; in this age group the nuclear area is only 75 micron 2. The cell size of the pinealocytes shows no differences between both age groups. From these data a nuclear:cytoplasmic ratio of 1:1.77 was calculated for the 30 to 40-year-old men. In the age group of the over 70-year-olds, this ratio is significantly decreased to 1:2.13. Concerning the nucleoli in the 30 to 40-year-old men a value of 10.1 micron 2 was measured, which is significantly different from the 7.8 micron 2 for the over 70-year-old patients. On the basis of well-known criteria of nuclear size and nuclear:cytoplasmic ratio, our study underlines the higher functional significance of the pineal gland in the younger decades of life.

Adult↗

PubMedDate not supplied

[Memory training: an important constituent of milieu therapy in senile dementia].

At the Memory Clinic in Basel we provide long-term memory training as part of our "milieu therapy". Mildly demented elderly out-patients attend weekly group sessions of 60 min for a special semistructured memory training. The goal is to relearn and practice strategies which help to preserve or extend the phase of autonomy and thus life quality and self-esteem. In several studies we tested the efficiency of the training on mood, global mental status, short-term memory, cognitive flexibility, and quality of life by comparing the performance of groups of patients attending the memory training to nontreated matched control groups after 1 year. We found that depression scores improved in a treated group and worsened in a control group, independently of diagnosis. Global mental status as measured by Mini-Mental-State Examination and performance on a figural and verbal fluency task remained stable for the memory training groups and declined in the control groups. Short-term memory declined in both groups, however, significantly only in the nontreated groups. The individual quality of life schedule showed stable or improved scores for the treated group and lower scores for the control group. We conjecture from these results that memory training is effective in mildly demented out-patients in delaying the progression of cognitive deficits.

Activities of Daily Living↗

PubMedDate not supplied

[Evaluation of a German version of WOMAC (Western Ontario and McMaster Universities) Arthrosis Index].

The WOMAC (Western Ontario and McMaster Universities) Osteoarthritis Index is a tested questionnaire to assess symptoms and physical functional disability. We adapted the WOMAC for the German language and tested its metric properties, test-retest reliability and validity in 51 patients with knee and hip OA. All WOMAC scales (pain, stiffness, function) were internally consistent with Cronbach's coefficient alpha ranging from 0.80 to 0.96. Test-retest reliability was satisfactory with intraclass correlation coefficients ranging from 0.55 to 0.74. All scales and the global index calculated as the mean of scale scores had a bimodal distribution and a slight ceiling effect. As hypothesized the WOMAC scales were associated with radiological OA-severity and limitations of range-of-motion. Patients with more severe symptoms and functional disability perceived more limitations in their roles at home and at work. The presented German version of the WOMAC is a reliable and valid instrument for the assessment of symptoms and physical functional disability in patients with knee and hip OA.

Activities of Daily Living↗

PubMedDate not supplied

[Evaluation of a German questionnaire version of the Lequesne cox- and gonarthrosis indices].

The Lequesne algofunctional indices for the knee and the hip require a physician interview. We adapted the Lequesne indices for the German language and tested the metric properties, test-retest reliability and validity of a self-report questionnaire-format in 51 patients with hip or knee OA. The symptom and function components as well as the global indices had a high test-retest reliability (intraclass correlation coefficient knee: 0.87/0.92 and 0.86, hip: 0.96/0.85 and 0.94). The symptom component showed an insufficient internal consistency (Cronbach's coefficient alpha knee: 0.55; hip: 0.63). Also, the symptom component was not or only weakly associated with radiological OA-severity and the limitations of range-of-motion. The most likely explanation is the grading of the Lequesne symptom questions which addresses such different concepts as pain presence, pain on movement, duration of pain and appearance of pain after a certain period of time. Because of the insufficient internal consistency and questionable validity the tested self-report German-version of the Lequesne algofunctional indices may not be recommended for use in clinical research and practice.

Activities of Daily Living↗