Engineering of functional contractile cardiac tissues cultured in a perfusion system.

Overcoming the limitations of diffusional transport in conventional culture systems remains an open issue for successfully generating thick, compact and functional cardiac tissues. Previously, it was shown that perfusion systems enhance the yield and uniformity of cell seeding and cell survival in thick cardiac constructs. The aim of our study was to form highly functional cardiac constructs starting from spatially uniform, high density cell seeded constructs. Disk-shaped elastomeric poly(glycerol sebacate) scaffolds were seeded with neonatal rat cardiomyocytes and cultured for eight days with direct perfusion of culture medium or statically in a six-well plate. In the perfusion experimental group, the integrity of some disks was well maintained, whereas in others a central hole was formed, resulting in ring-shaped constructs. This allowed us to also study the effects of construct geometry and of interstitial flow versus channel perfusion. The ring-shaped constructs appeared to have a denser and more uniform deposition of extracellular matrix. In response to electrical stimulation, the fractional area change of the ring-shaped constructs was 7.3 and 2.7 times higher than for disk-shaped tissues cultured in perfusion or statically, respectively. These findings suggest that a combination of many factors, including scaffold elasticity and geometry and the type of perfusion system applied, need to be considered in order to engineer a cardiac construct with high contractile activity.

[The "Barthel Index": alternative to expertising in compulsory care insurance?]. / Der Barthel-Index: eine Alternative zum Begutachtungsverfahren in der Pflegeversicherung?

Measuring the level of care needed is difficult and since the introduction of nursing care insurance in Germany in 1995 the assessment method applied by the MDK (Medizinischer Dienst der Krankenversicherung) has repeatedly been criticised. The method is very costly and not broadly tested for its validity and reliability. The question arises whether similar results can be obtained by applying another instrument, like the Barthel Index (BI), which is easier to use and more reliable. In this article the authors show - based on a preliminary study in 1999 - that by using the Barthel Index a discriminance analysis will show identical results in 80 % of all cases. The authors regard this identical measurement of care needs, which is reached by scoring only ten items (BI) versus thirty (MDK's assessment method) and with a presumingly higher reliability, as a major progress and reason enough for further discussion and studies of the use of the Barthel Index for care needs assessment.

[A different approach--a new instrument for expert assessment of disability stages?]. / Es geht auch anders--Ein neues Instrument zur Begutachtung der Pflegestufen?

A New Tool for Expertising Nursing-Care Need? Since the introduction of the long-term care insurance in April 1995 criticism of the mode of expertise used to assign a particular nursing status to a patient has not ceased. Nursing status is required to receive monetary benefit from the long-term care insurance. According to the code of social law (SGB XI) nursing status is based on the total amount of time in minutes a care-needing person requires help to perform certain activities of daily living (ADL). This time-based classification is the bone of contention. As the currently used classification instrument has not been validated and is not reliable, it has been the aim of the present study to introduce a more objective mode of expertise. In our study we used the Barthel-Index as an instrument that allows to assign nursing status to a person in agreement with the person's respective ability to fulfil ADL. In a prospective study 252 patients were examined by the raters of the MDK Bavaria (Medical Service of Health Insurance) according to the SGB XI and the Barthel-Index. On the basis of the Barthel-Index and a certain discriminatory function more than 86% of the patients were assigned the same nursing status as with the normally used mode of expertise. Most of the differing results were borderline cases between two levels of nursing status. The new mode of expertising results in a more balanced distribution of different levels of nursing status. Therefore, the Barthel-Index in combination with the discriminatory function is as effective as the normally used mode of expertising. It is a valid and reliable instrument which could well replace the mode of expertising used so far.

[Systemic treatment of oral lichen planus with an aromatic retinoid (Ro 10-9359)]. / Zur systemischen Behandlung des oralen Lichen planus mit einem aromatischen Retinoid (Ro 10-9359).

Experiences in the treatment of lichen planus mucosae (including the erosive type) are reported. Good therapeutical results could be obtained in all patients. Leukoplakic patches showed a partial involution and in some cases erosive alterations healed completely. After interruption of medication a relapse was observed in most cases. Concerning side effects, some patients complained in particular of minor dryness of both labial and nasal mucosa and of diffuse hair effluvium.

Autoradiographic study on some proliferative properties of human buccal mucosa.

This study was designed to investigate the proliferative activity of the buccal mucosa in healthy adult persons with regard to individual age. Punch biopsy specimens were taken from the buccal mucosa of 19 individuals (10 females, 9 males) ranging in age from 24 to 80 years, and were then examined autoradiographically, applying nuclear 3H-thymidine labelling in vitro under oxygen pressure of 2.2 atm. The mean total labelling index in the progenitor compartment amounted to 26.0 +/- 2.6% including 6.2 +/- 2.0% labelled basal nuclei and 19.8 +/- 2.6% labelled suprabasal nuclei. Related to 1,000 mu surface length, the mean number of basal cells runs up to 270.7 +/- 38.6 and the total nuclear labelling index to 70.9 +/- 10.4. This high rate of S phase nuclei, exceeding that of the epidermis several times, depends on the ample progenitor compartment as well as on the basal epithelium length which, as compared to the epithelium surface length, was shown to be extended by a mean proportion of 1.75. None of the autoradiographic results obtained in the present study revealed an age dependency of the buccal mucosa proliferative activity. The magnitude of the proliferative pool constitutes the matrix of the high renewal rate of the healthy buccal mucosa and provides a steady state of superficial cell loss and basal cell regeneration, that was proved, at least in the normal mucosa, to continue until senile age.

[Some measures of proliferative activity in normal and leukoplakic buccal mucosa (author's transl)]. / Zur Proliferationskinetik der normalen und leukoplakischen Wangenmucosa.

In 29 patients, the DNA synthesis rate of clinically healthy buccal mucosa epithelium in comparison to benign buccal leukoplakias has been studied by in vitro-autoradiography. The proliferative activity has been determined by means of the 3H-labelling indices of basal cells (LBC) and suprabasal cells (LSBC) including the total of labelled epithelium cells and the quotient of LBC:LSBC as well. The progenitor compartment of both leukoplakic and normal buccal epithelium comprises the stratum basale and the adjacent 2-3 layers of suprabasal cells. Around 70% of the DNA synthesis of normal mucosa was found in the suprabasal nuclei of the progenitor compartment. In the leukoplakic mucosa, some displacement of the labelled nuclei in the progenitor compartment resulting in a statistically significant change of the quotient of LBC:LSBC in favour of LBC was determined. Moreover, the leukoplakic specimens showed a moderate decrease of the mean proliferative activity of the total of labelled epithelial cells which may be due to a diminished exfoliation of cornified cells from the hyper(ortho)keratotic surface. It is supposed that in chronic oral leukoplakias some variation of the steady state between renewal and desquamative loss of epithelial cells is operating as far as no precancerous condition is present.

[Comparative histological and autoradiographic investigations on benign oral leukoplakias (author's transl)]. / Vergleichende histologische und histoautoradiographische Untersuchungen an benignen oralen Leukoplakien.

Proliferation was studied in 18 patients with benign oral leukoplakias of the buccal mucosa by in vitro labelling with 3H-TdR. Identical investigations were performed in clinically normal mucosa of the same patients. Significant differences were found between the LI of both groups. On the other hand the total of labelled cells per 100 micron length of the basal membrane was approximately equal in leukoplakias and normal mucosa. In the majority of cases the LI was increased in leukoplakic regions whereas the number of labelled suprabasal cells was lowered compared to normal. These findings are supposed to be a consequence of shifting of epithelial keratinization to the lower stratum spinosum. From that results an increased proliferation in the basal cell layer.

[Experiments and theoretical cell kinetic calculations on the problem of in vivo synchronization with vincristine in L 1210 ascites tumor cells and crypt cells of the mouse (author's transl)]. / Experimentelle untersuchungen und zellkinetische berechnungen zur frage der synchronisation mit vincristin in vivo (mäuseleukämie l 1210, krypten-epithelien der maus)

Experiments are described on synchronizing L 1210 ascites tumor cells and jejunal crypt cells of the mouse with vincristine. In both cases the percentage of mitoses increases to a peak value 4 hrs after application of vincristine and decreases during the following 8 hrs ("releasing time") to the level of the normal mitotic index. Following this first mitotic peak no futher peak of neither the mitotic nor the labeling index was observed during 48 hrs in L 1210 ascites tumor cells and during 38 hrs in crypt epithelia. Thus, in both cell types it was not possible to obtain a synchronizing effect by applying vincristine. Based on cell kinetic considerations it was examined whether peaks of the mitotic as well as the labeling index can be expected at all under the given circumstances. The results show that the theoretical course of the mitotic index coincides with the measured values. This means that no peak of the mitotic index can be expected from the theoretical point of view. In calculating the time course of the labeling index the theoretical curve proved to depend to a high degree on the variations of the cycle time which are not known in detail, especially not after application of vincristine. However, the theoretical conditions show that also in the case of the labeling index no peak can be expected. This agrees with the experimental results. The general significance of a long "releasing time" of 8 hrs or more for the lack of a synchronizing effect is discussed.

[Experimental and theoretical studies on the in-vivo production of a partially synchronous proliferating cell population with vincristine]. / Experimentelle und theoretische Untersuchungen zur Erzeugung einer teilsynchron proliferierenden Zellpopulation mit Vincristin in vivo

The problem of whether vincristine can be used to synchronize partially cells in vivo was investigated. After injection of 0,0045 mug vincristine/g body-weight into mice practically all L1210-ascites tumour cells entering mitosis were arrested in metaphase up to the fourth hour. However, no second peak of the mitotic index was observed within 48 hours. Calculation of the theoretical mitotic index to be expected under the present experimental conditions also shows no second peak. The reason for this lack of synchrony is the long releasing time of the arrested cells.