[The amnion epithelium in hydramnion. Light- and electron-microsocpy studies]

Human amniotic epithelium was examined in cases of pregnancy complicated with hydramnios; the light- and electronmicroscopical results were compared with those of epithelium in normal pregnancy. The cells of the hydramniotic epithelium show an increased number of microvilli in apical and lateral cell surfaces. There are also a greater number of desmosomes and enlarged intercellular spaces. In a single case where hydramnios was correlated with maternal diabetes mellitus the amniotic epithelium is characterized by local foci showing cellular dystrophy.

Transient kinetics of Ca2+ transport of sarcoplasmic reticulum. A comparison of cardiac and skeletal muscle

Current evidence supports similar functions and mechanisms for cardiac sarcoplasmic reticulum (CSR) as for skeletal sarcoplasmic reticulum (SSR). It is thought that the slower relaxation rate of cardiac muscle compared to fast skeletal muscle reflects the lower ATPase activity and calcium transport of CSR. Possible quantitative differences is phosphorylation, dephosphorylation, and calcium transport of the isolated preparations are studied using a quench-flow apparatus. The results show that both CSR and SSR bind calcium tightly in the absence of ATP, and coupling of E approximately P formation and calcium transport occurs in the transient phase of ATP hydrolysis. The rate of phosphorylation (t-1/2 - 10 ms) of sarcoplasmic reticulum (SR) preloaded with calcium is the same for cardiac and skeletal preparations. However, the rates of dissociation of extra vesicular calcium (10 s-1 versus 15 s-1), phosphorylation of calcium-free SR, and dephosphorylation of E approximately P (8 s-1 versus 12 s-1) are lower for CSR than for SSR. By computer simulation, the apparent rate constants associated with the reduced rates of phosphorylation of calcium-free SR were: 12 s-1 for CSR and 63 s-1 for SSR in the presence of high Mg2+. The difference in the rates may be partly responsible for the lower levels of ATPase and calcium transport activity with characterize cardiac muscle preparations.

[Long-term cultures of trophoblast cells and mixed trophoblast cultures as a model for in-vitro studies (author's transl)]

Trophoblast cell-cultures provide a much promising model for qualitative and quantitative in-vitro-examinations of immunological, morphological and biochemical items. In the present paper an attempt has been made to analyze the light-microscopically identificable morphological modifications of the cultured cells under standardized culture-conditions in a temporary order. Furthermore, a number of single cases is presented in which mixed cultures of trophoblast cells with heterologous cells of embryonic origin and with cells derived from adult malignoma were tried.

Rise and fall of cyclic AMP required for onset of lymphocyte DNA synthesis

The adenosine 3',5'-monophosphate (cyclic AMP) levels of mouse lymphocytes rose and fell sharply 10 hours after stimulation with concanavalin A. Treatment of the cells with indomethacin reversibly prevented the increase in cyclic AMP and the subsequent onset of DNA synthesis. When the heightened cyclic AMP before S phase was maintained by either inhibiting phosphodiesterase or by adding the 8-bromo derivative of cyclic AMP, DNA synthesis was also blocked. Both the increase and decrease in cyclic AMP appear to be required for progression of lymphocytes into the S phase of growth.

Increased phosphorylation of a specific protein in mitogen-stimulated lymphocytes

The phosphorylation of proteins from murine splenic lymphocytes was studied. When the phosphorylation of proteins in extracts from Concanavalin A (ConA)-treated lymphocytes was compared with that of resting lymphocytes, there was only one detectable difference between them. A protein of 135,000 mol. wt was highly phosphorylatable in extracts from ConA-treated cells while phosphate incorporation into this protein was slight in extracts from untreated cells. This effect could be observed 12 h after ConA treatment and was maximal during S phase. This soluble protein was also phosphorylated in intact lymphocytes.

Bi-morphic atrial flutter

A case of atrial flutter whose classic "saw-tooth" morphology, resistant to full doses of digoxin and quinidine, was changed to an unusual form by low energy direct current shock is presented. The atrial and ventricular rates remained identical in spite of the different F wave pattern before and after attempted cardioversions. 0.5 mg digoxin was given after cardioversion failed and the patient reverted to normal sinus rhythm. This case strengthens the theory of rapidly discharging atrial focus as a mechanism of atrial flutter and the case for a change in intra-atrial conductions as cause for change in atrial electrograms.

Aneurysm of the body of the left atrium presenting with chest pain

A patient with aneurysm of the body of the left atrium presenting with angina pectoris and mild congestive heart failure, but completely normal coronary arteriograms, is reported. A deverticulum seen in the left ventricular angiogram, read as a ventricular diverticulum, was found at surgery to be an aneurysm of the body of the left atrium. The possible etiologics and complications of the left atrial aneurysm are briefly discussed.