Correlation of the production of gonadotropic and sex hormones in boys and girls during sex maturation

There is an early period of puberty in boys at the age of 10 to 13, accompanied by an increase in the level of follicle stimulating hormone and a low secretion of luteinizing hormone and testosterone, with no secondary sexual signs. The beginning of an increase in the luteinizing hormone and testosterone concentration in boys coincides with the development of secondary sexual signs. The stabilization of the level of luteinizing hormone takes place in boys already at the 2nd degree of the sexual development. The secretion of luteinizing hormone at this point corresponds already to the normal level in adult men. The level of testosterone in the blood continues to increase and does not reach its definitive level until after the age of 17, or at the 5th degree of sexual development. Like in boys, the increase of the follicle stimulating hormone in girls precedes the increase of the luteinizing hormone secretion. The beginning of the increase in the follicle stimulating hormone coincides with an increase in the level of estrogens and testosterone in the blood, and with the appearance of secondary signs of sexual maturation. The increase of the luteinizing hormone secretion takes place later in girls than in boys and is accompanied by a new and significant increase in the level of estrogens in the blood. At the 2nd degree of sexual development, the level of testosterone in the blood of girls is substantially higher than at the other stages.     

Clival chordoma

Chordomas are uncommon tumors arising from embryonic remnats of the fetal notochord. The spheno-occipital and sacrococcygeal regions account for over 90 per cent of cases, the remaining 10 per cent occurring anywhere along the vertebral axis. A case of chordoma arising from the clivus is presented with a view to discussing management. The ability to obtain reasonable survival times associated with a useful and meaningful quality of life is emphasized. This may be accomplished by repeated, judicious surgical intervention with surprising ease and little morbidity to the patient in spite of its intracranial location.     

Potential difference across subcellular particle membranes. II. Compensation method of measurement

"Zero-loop" of the molecular potential transformer of submitochondrial particles (SMP) is separated from the remaining electron transfer chain by rotenone, and its e.m.f. ET=0,003+RT/2F in [NADP X H] [NAD+]/[NADP+] [NAD X H] volts is used in the compensative method of measurement of the potential difference across the SMP membrane (delta USMP). The phospholipid membrane, measuring the concentration of the penetrating anions in the solution contained SMP, is used as "zero-indicators". This concentration drops monotonically with increase in delta USMP. Delta USMP is equal to ET when the addition of substrates of transhydrogenase reaction with definite ET does not change the potential across phospholipid membrane.     

DNA polymerase of Dictyostelium discoideum

Only one molecular weight species of DNA polymerase was found in different developmental stages of the eukaryotic microorganism Dictyostelium discoideum. The molecular weight of this DNA polymerase is estimated to be about 127 000 by sucrose gradient centrifugation. The enzyme is present in all stages of growth and development, including dormant spores. All DNA polymerase activity is lost upon incubation of the crude extract with N-ethylmaleimide. The reaction properties, molecular weight and N-ethylmaleimide sensitivity of the D. discoideum DNA polymerase are similar to those of the DNA polymerase-alpha from mammalian sources.     

Tracheal obstruction associated with a fungus ball. A case of primary tracheal candidiasis

A case of transient filling defects in the renal pelves and ureters, secondary to spontaneously occurring acquired anticoagulants, is presented. The relationship of this entity to hemophilia, immunologic disorders, such as systemic lupus erythematosis, and normal post partum patients is discussed. The differential diagnosis for filling defects in the renal pelvis is reviewed.     

Heat transfer efficiency in a fliuidized bed

The equilibrium stage concept used in staged contacting operations was adopted as a measure of heat transfer efficiency for a fluidized bed. A simple model was developed which postulates that solids flow through the bed can be by perfect mixing, plug flow and short-circuiting. Efficiencies were determined experimentally in a 150 mm diameter fluidized bed with air as the fluidizing medium and sand as the solid. Heat transfer efficiencies greater than 100% were obtained indicating that small diameter, low aspect ratio fluidized beds do not behave as perfect mixers. The results indicate that heat transfer measurements can be used to develop information on solids flow behavior.