Caliber of the lumen of the eustachian tube pre-isthmus in infants and children

We measured the eustachian tubes in temporal bones taken from infants and children. These specimens included eustachian tubes from 35 normal temporal bones and 13 temporal bones containing acute and secretory otitis media. All temporal bones were serially sectioned for histological studies. The lumen of the third portion of each eustachian tube (i.e., the pre-isthmus or the physiological isthmus) was measured with the aid of a grid mounted on a microscope. These measurements showed: (1) the eustachian tube lumen grows and enlarges to a small degree with age; (2) each age group has a considerable variation in the size of the lumen which is compatible with natural biological distribution; (3) no statistical differences were found in the size of the pre-isthmus lumina of those eustachian tubes from temporal bones showing acute or secretory otitis media when compared with the lumina of eustachian tubes in non-pathological ears.     

Screening for induction of differentiation and toxicity to blast cells by chemotherapeutic compounds in human myeloid leukemia

Bone marrow cells from 9 patients with acute myeloid leukemia and 1 patient with a blast crisis of chronic myeloid leukemia were cultured to determine their ability to be induced to differentiate by different chemotherapeutic compounds. Five of these 10 patients showed differentiation to granulocytic and/or monocytic cells by culture with medium containing the myeloid cell differentiation-inducing protein MGI-2. Actinomycin D induced differentiation in cells from 2 of the patients who did not show differentiation with MGI-2 containing medium. In these 7 patients there was an increase in the ratio of differentiated myeloid cells to blasts. None of these 10 patients showed induction of differentiation by cytosine arabinoside, adriamycin, or daunomycin, but treatment with these compounds showed in some patients an increase in the ratio of differentiated myeloid cells to blasts. The results indicate that this ratio can be increased by differentiation and also in some patients by toxicity to blast cells. With dexamethasone or vinblastine there was no induction of differentiation and no increase in this ratio in any of the 10 patients tested. After in vivo chemotherapy with low dose cytosine arabinoside, cells from one patient showed a similar response in culture to actinomycin D as cells before chemotherapy, whereas in another patient the cells had acquired the ability to respond to actinomycin D. In contrast, after high-dose in vivo chemotherapy with cytosine arabinoside and daunomycin, cells from a third patient seemed to have lost the ability to differentiate in vitro by MGI-2 containing medium or actinomycin D. The results indicate that pre-screening for differentiation-inducing compounds and compounds that show toxicity to blast cells should be useful to select the appropriate compounds to be used for therapy, and that it is advisable to screen the cells both before and after initiation of therapy.     

Provoked visual impairment in multiple sclerosis studied by visual evoked responses.

Pattern-reversal VERs were studied during the visual impairment provoked by exercise in 2 patients with demyelinating optic neuritis. It was found that the transient reduction in visual acuity was correlated to a transient decrease in the amplitude of the major positive component of the VER, whereas no significant changes could be observed in the latency of the response. The normal VER was not influenced by exercise.     

Immunoreactive calcitonin in brain regions and pituitary of sheep

In this study we have investigated the presence of immunoreactive calcitonin in the central nervous system and pituitary of sheep. The calcitonin concentrations were determined radioimmunologically by two different antibodies. We have demonstrated calcitonin in extracts of areas of the central nervous system, whole pituitary, thyroid gland and plasma of 21 sheep. The concentrations were (ng/g wet weight, mean values +/- SE): thyroid 16.0 +/- 4.4, pituitary 2.03 +/- 0.34, reticular formation 1.64 +/- 0.25, substantia nigra 1.53 +/- 0.46, dentate nucleus 1.11 +/- 0.27, putamen 1.05 +/- 0.35, hippocampus 0.97 +/- 0.17, fornix 0.96 +/- 0.15, anterior thalamus 0.92 +/- 0.28, mammillary body 0.88 +/- 0.12, cerebellum 0.86 +/- 0.09, caudate nucleus 0.84 +/- 0.11, posterior hypothalamus 0.83 +/- 0.19, epiphysis 0.75 +/- 0.25, thalamus centralis 0.71 +/- 0.10, almond nucleus 0.69 +/- 0.16, medulla oblongata 0.67 +/- 0.15, anterior hypothalamus 0.66 +/- 0.20, precentral gyrus 0.66 +/- 0.16, globus pallidus 0.63 +/- 0.31, postcentral gyrus 0.36 +/- 0.08 and plasma (ng/ml) 0.058 +/- 0.013. Our results demonstrate that immunoreactive calcitonin is present in the central nervous system (CNS) of sheep, compatible with a neurotransmitter function for this hormone.     

Independent regulation of two types of aryl hydrocarbon (benzo(a)pyrene) hydroxylase in mammalian cells.

Aryl hydrocarbon (benzo(a)pyrene) hydroxylase induced by dibutyryl cyclic AMP (dcAMP), plus aminophylline (AHH I) can be ditsinguished from the hydroxylase induced by benz (a) anthracene (AHH II) by its lower Km for benzo (a) pyrene. Treatment with the combination of benzo (a) anthracene and dcAMP plus aminophylline induced both AHH I and AHH II activities. After optimal induction of AHH II activity by benz (a) anthracene, the addition of dcAMP plus aminophylline gave an induction of AHH I. Although AHH I activity declined to an almost basal level 24 h after treatment with dcAMP plus aminophylline, the addition of benz (a) anthracene prevented this decline. Inducibility by dcAMP plus aminophylline or by benz (a) anthracene varied in different cell lines. Some cell lines were induced by both substances, with a higher induction by benz (a) anthracene, while other lines were inducible only by benz (a) anthracene, and a third cell type was not inducible by either. Selection for resistance to benzo (a) pyrene of a cell line inducible by both compounds resulted in a fourth cell type which was more inducible by dcAMP plus aminophylline than by benz (a) anthracene. The results suggest that there is an independent regulation of hydroxylase AHH I and AHH II and that the induction of these two enzyme activities is determined by different genetic controls.