Cytokinesis in the green alga Eremosphaera viridis: Plasmalemma formation from "open membranes".

Cytokinesis in the unicellular chlorococcalean alga Eremosphaera viridis de Bary has been investigated by electron microscopy of thin sections. The new plasmalemmata of the daughter cells in this organism form centrifugally within a phycoplast. Unlike other cell division systems each new plasmalemma is formed, not by the fusion of vesicles, but rather by the fusion of "open membranes" which are characteristically heavily stained.

Immunochemotherapy of lung cancer.

After surgical resection of their primary lung cancer, 33 patients were randomized into one of three groups. The first received high-dose methotrexate once per month with citrovorum rescue, for 3 months. The second group were immunized monthly with a homogenate of Freund's complete adjuvant and carefully characterized soluble antigen derived from allogeneic lung cancer cells of appropriate histology, for 3 months.

The effect of potassium on the cell membrane potential and the passage of synchronized cells through the cell cycle.

The cell membrane potential of cultured Chinese hamster cells is known to increase at the start of the S phase. The putative role of the cell membrane potential as a regulator of cell proliferation was examined by following the cell cycle traverse of synchronized Chinese hamster cells in the presence or absence of high exogenous levels of potassium. An increase in external potassium levels results in a depressed membrane potential and a reduced rate of cell proliferation.

The hypothalamo-neurohypophysial complex in organ culture: effects of metabolic inhibitors, biologic and pharmacologic agents.

Organ cultures of the guinea pig hypothalamo-neurohypophysial complex synthesize the octapeptide hormone, vasopressin, a specific product of the neurosecretory cells of the supraoptic nucleus. Inhibitors of both protein and RNA synthesis (cycloheximide and bromotubercidin respectively) were found to block vasopressin biosynthesis. In the presence of bromotubercidin, the apparent half-time of decline in the rate of hormone biosynthesis was about 28 h.

The hypothalamo-neurohypophysial complex in organ culture: morphologic and biochemical characteristics.

Organ cultures of the guinea pig hypothalamo-neurohypophysial complex could be maintained for periods as long as 3 weeks. Morphological studies using conventional light microscopy as well as electron microscopy indicate that neurosecretory cells remain viable during this time. Biochemical studies show that the capability of the cultures to synthesize a normal spectrum of cellular RNA species is impaired during the initial day in culture, but that this capability is restored after 4-5 days.

Stimulated vasopressin synthesis by a fetal hypothalamic factor.

The hypothalamo-neurohypophyseal complex (HNC) of the fetal guinea pig shows a dramatic increase in its content of vasopressin and neurophysin between the 40th and 55th days of gestation. The values for radioimmunoassayable hormone and binding protein are at day 40, 2 milliunits and less than 0.1 microgram; and at day 55, about 100 milliunits and 10 micrograms, respectively.

Electrical activity in embryonic heart cell aggregates. Developmental aspects.

Action potential parameters were measured in beating heart cell aggregates which were formed from trypsin-dissociated cells of embryonic chick heats aged 2 1/2, 4 or 7 days. 1. In aggregates composed of cells from the whole heart there was an increase in the maximum diastolic potential, overshoot, maximum rate of rise of the action potential (V max), and action potential duration between days 2 1/2 and 7.

Electrical activity in embryonic heart cell aggregates. Pacemaker oscillations.

Aggregates were formed from dissociated heart cells of 7-day chick embryos. When spontaneous action potentials were blocked with 10-8 to 10-7 g/ml tetrodotoxin (TTX) oscillatory pacemaker potentials were sometimes seen. The emergence of these pacemaker potentials was critically dependent on the external potassium concentration.

[Cytofotometrically Determined DNA-pattern of premalignant cases of dysplasia of the cervix uteri. Contribution to the problem of morphologic definition and clinical sigificance of these lesions (author's transl)].

24 cases of probably benign and precancerous epithelial lesions of the cervix uteri were analysed cytofotometrically. The specimens were stained after the method of Feulgen. Benign epithelial changes for instance metaplasia, regenerating epithelium, atrophic and parakeratotic epithelium, basal cell hyperplasia and cervix epithelium irritated by inflammation, had normal diploid DNA-pattern.

[Pulsecytophotometric analysis of cervical cells of postmenopausal women (author's transl)].

49 suspensions with cells of the cervix uteri exclusively taken from postmenopausal women were analysed with the pulsecytophotometer. 7 of these cases had an histologically verified invasive cancer of the cervix uteri. There were no false negative results, the percentage of false positive measurements was about 30%.

Effect of a screening program on changing patterns of lead poisoning.

A biphase program of screening and treating high-risk children for lead poisoning resulted in a 30% fall in mean lead values in the target areas over a 5-year period. The mean and median for subjects under 6 years was 4-10 mug/100 ml higher than for those over 6. Median for a high incidence area was 42 mug/100 ml in 1967 and 30.