Junctions on the maternal blood surface of the human placental syncytium

Terminant chorionic villi of the human placenta at 8, 9, 12, 14 weeks' gestation and at full term have been studied in freeze-fracture replicas and in thin sections. In replicas, maculae occludentes of different size have been detected in all placental samples on the cleaved plasma membrane of the free (maternal) surface of the syncytiotrophoblast. In thin sections they are located in narrow invaginations of the syncytium luminal plasma membrane. These invaginations are in turn similar to flattened vesicles (also associated with junctions) located in the underlying syncytioplasm. Possible origin and function of the junctions on the syncytium free surface are discussed.

Donor pretreatment: rat heart allograft survival and measurement of passenger leukocyte depletion with indium-111

The present experiment was designed to study the relationship between rat heart allograft survival and passenger leukocyte depletion in donor-pretreated animals. Untreated Lewis rats served as recipients of cardiac allografts from treated Fischer rats. Passenger leukocyte depletion was assayed with indium-111 oxine-labeled leukocytes (predominantly lymphocytes) which were infused into donor rats 6 hr before treatment with cyclophosphamide, antilymphocyte globulin (ALG), sublethal total body irradiation, or in vitro perfusion-preservation of the isolated beating heart. In vivo pretreatment of the donor with cyclophosphamide resulted in a significant prolongation of heart allograft survival but effected no reduction in graft-labeled lymphocytes. In vitro perfusion-preservation of the donor heart, for 1 to 2 hr, led to a 50 to 60% reduction in graft-labeled lymphocytes but failed to significantly prolong the survival of the heart allografts. Both ALG and sublethal total body irradiation donor pretreatments resulted in significant prolongation of heart allograft survival and a 20 to 25% labeled passenger lymphocyte depletion. This study demonstrates that there is no direct correlation between allograft survival and the degree of mobile passenger lymphocyte depletion, suggesting that the efficacy of leukocytotoxic donor pretreatment methods may depend in part on alternative mechanisms.

Amniotic epithelium in diabetes mellitus. Light and electron microscopic examination

The epithelium of human amnion was examined under the light and electron microscopes. Morphologically, the amniotic epithelium in diabetes mellitus differs from that of a normal term specimen by the following characteristics: 1. An increase in the number of beta-shaped glycogen granules and lipid droplets; 2. The presence of epithelial areas with dead cells; 3. Thickening of the basal membrane. Areas with dead cells could be identified in the amniotic epithelium of diabetic patients. These were not found in normal term pregnancies nor in other types of high-risk pregnancies, such as non-diabetic hydramnios, rhesus incompatibility, or pretoxaemia/toxaemia. These findings may indicate that the areas are specific to diabetes mellitus.

[Examination of placenta by light and electron microscope in a woman patient with renal transplant (author's transl)]

The placenta of a woman who had received a renal graft before she became pregnant was examined. The light- and electronmicroscopical results were as follows: 1. Enlargement of the granulated endoplamatic reticulum in the syncytium. 2. Increase of the syncytial knots. 3. Persistence of exceeding numbers of Langhans cells. These alterations coinciding with the immune suppressive therapy might play a role for the initiation of the growth retardation as observed in children of renal-grafted mothers.

Diagnosis of Strongyloides stercoralis in sputum cytology

A unique case of hyperinfection with Strongyloides stercoralis in an apparently immunosuppressed host is reported. The organism in various stages of maturation was initially detected by routine sputum cytology. Papanicolaou-stained smears from scrapings of jejunal and colonic mucosa provided specific confirmation of the parasite. Postmortem examination also showed massive tissue and vascular invasion in the intestine with cerebral and pulmonary dissemination.

[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.