[Quality control and cytogenetic analysis of human pre-embryos fertilized and cultured in vitro].

For the purpose to evaluate in vitro culture conditions of human preembryos, the efficacy of conventional culture and co-culture systems on embryonic development and genetic disorders was studied. Firstly, the development of cultured mouse embryos grown in standard media (Whitten's, GPM, HFT and Ham F10) or in HFT medium with different helper cell layers was compared. Embryonic growth was substantially reduced during in vitro culture, demonstrably by impaired cell proliferation, compared with in vivo controls. In in vitro fertilization and culture condition, SCEs of blastocysts were significantly increased. Development in co-culture with the feeder layers was notably better than in standard media. These results suggest that human preembryos could be rescued by the use of helper cells. Increased developmental rates and the cell numbers of blastocysts were the most evident morphological features of human preembryos that developed in co-culture with uterine luminal epithelial cells. However mosaicism may be caused by in vitro culture conditions and its onset may indicate when a disturbance in the embryonic development has occurred. It is advisable to perform further research into the mechanism of feeder cell-embryo interaction for understanding the optimal conditions of embryonic development in vitro.

A new tobacco mosaic virus vector and its use for the systemic production of angiotensin-I-converting enzyme inhibitor in transgenic tobacco and tomato.

We have developed a new tobacco mosaic virus (TMV) RNA vector and have used it initially to systemically produce an angiotensin-I-converting enzyme inhibitor peptide (ACEI) in tobacco and tomato plants. This vector incorporates a six base 3' context sequence, which permits readthrough of the stop codon for the TMV 130K protein gene, inserted between the stop codon for the coat protein (CP) gene and ACEI gene. In contrast to previous TMV RNA vectors, the new vector produced both an intact CP and a fused protein consisting of CP and ACEI (CP-ACEI). As a result, the vector could form virus particles and spread systemically from inoculated to non-inoculated leaves. In tomato plants, production of ACEI in fruit was also achieved.

[A new treatment of hyperkalemia in renal failure with selective beta 2-adrenergic stimulant, terbutaline sulfate].

Plasma potassium lowering effect of a selective beta-2 adrenergic stimulant, terbutaline sulfate (TRB) was investigated in fourteen patients with chronic renal failure (CRF) receiving maintenance hemodialysis. Fourteen CRF patients with chronic glomerulonephritis (CGN) (5 male, 2 female) and diabetes mellitus (DM) (3 male, 4 female) were infused with 0.4 mg TRB dissolved in 100 ml of 10% maltose solution. Serum potassium level in the CGN group significantly (p less than 0.01) decreased after 20 minutes infusion and maximum lowering effect (1.1 mEq/l) was obtained 40 minutes after the start. On the other hand, the maximum lowering effect of serum potassium level in the DM group (0.77 mEq/l) was obtained 60 minutes after the start. No serious metabolic and hemodynamic side effect was observed except only slight transient tachycardia in 2 CGN patients and 3 DM patients. Thus, a beta-2 selective adrenergic stimulant, terbutaline sulfate may be useful for acute treatment of hyperkalemia in CRF patients by way of the stimulation of potassium uptake in the cells.

Constitutional and echocardiographic variability of the normal electrocardiogram in children.

To understand better the normal electrocardiogram and to improve the diagnosis of left ventricular hypertrophy (LVH), the authors examined RV5 and SV1 + RV5, using a special computational technique, in relation to body size, heart size, and the distance between the heart and the chest wall in 7-year-old normal subjects. Boys and girls were analyzed separately. Using multiple regression analysis with a total of 16 constitutional and echocardiographic parameters as the predictor variable, the authors selected a minimum set of parameters and found that the greater the left ventricular mass (LVM) and the left ventricular cavity and the shorter the distance between the heart and the chest wall, the greater the RV5 and SV1 + RV5. In subjects with LVH in whom these parameters vary, SV1 + RV5 is preferable to RV5 for the electrocardiographic diagnosis of LVH, because LVM correlates more significantly with SV1 + RV5. In a similar analysis, using principal components as the predictor variable, no significance level was reached for the first principal component that represented size. This indicates that RV5 and SV1 + RV5 are in a constant range, irrespective of the body size and accompanying heart size.

Considerations on the nature of irregularity of the sequence of RR intervals and the function of the atrioventricular node in atrial fibrillation in man based on time series analysis.

Using sinus arrhythmia as a control, we elucidated the random nature of RR intervals during atrial fibrillation in man and determined the function of the atrioventricular (AV) node from the variability of RR intervals. The major difference between the characteristics of sinus arrhythmia and those of atrial fibrillation is the presence of a significant correlation between successive intervals in the former. Since the pattern of distribution of RR intervals in atrial fibrillation is unimodal and skewed to the right and so can be fitted to an Erlang distribution, atrial inputs can be considered to be summated to a certain threshold for ventricular activation in the N region of the AV node, the number of cumulative atrial inputs corresponding to this threshold being the phase of this Erlang distribution. The function of the AV node during atrial fibrillation is to transform an exponentially distributed input into an Erlang-distributed output. Loss of inputs occurs between the atria and the N region and the greater the loss of inputs the slower the ventricular response. However, the greatest loss occurs in the N region for summation of atrial inputs required to elicit ventricular activation.

A study on the irregularity of the sequence of R-R intervals in chronic atrial fibrillation in man based on the time series analysis and the information theory.

The mechanism of the irregularity of R-R intervals and especially the genesis of the long R-R intervals in atrial fibrillation were clarified. From the point of view of the present study, the sequence of successive R-R intervals can be regarded as a stochastic process, and consequently mathematical analyses can be applied, and the following conclusion could be obtained: the stability of the data, mathematically called stationarity, is present in the sequence of R-R intervals, and these intervals are independently and identically distributed. The probability density function is an Erlangian distribution with phase k of 20 to 26. Namely, as soon as, on the average, 20 to 26 atrial excitatory stimuli have arrived at the AV node, a threshold value of the AV node is reached and ventricular activation is induced. However, if we examine the mathematical structure of the sequence of successive R-R intervals in more detail, the following results can be evidently obtained: during atrial fibrillation with rapid ventricular response, the sequence of R-R intervals is completely independent, but with intermediate or slow ventricular response the adjacent R-R intervals correclate with each other and these adjacent intervals have at least the first order Markov property, which seems to be caused by the concealed conduction. Because of this Markow property due to the prolongation of the refractory period of the AV node, slow ventricular response results.