Anisotropic Absorption of Linearly Polarized Light by Cylindrical Molecules

A general theory relating the orientation of the transition moment in a chromophore to incident light, linearly polarized at an arbitrary angle, is discussed for cylindrical molecules. Experimental verification of this theory is presented for molecules of tobacco mosaic virus (TMV), T₂ DNA, and polyadenylic acid (poly-A).     

Microfluorometric detection of asymmetry in the centromeric region of mouse chromosomes

A lateral asymmetry in the centromeric region of mouse chromosomes is revealed in studies involving the BUdR quenching of 33258 Hoechst fluorescence. This cytologically detected asymmetry may reflect the unequal distribution of thymidine between the two chains of mouse satellite DNA.     

Gonadotropin release as a function of mating and steroid feedback in the female rat

The aim of this investigation was to study possible relationships between mating-induced and steroid-induced luteinizing hormone (LH) release in spayed Long-Evans rats. Large amounts of LH were released approximately 7 hr following progesterone injection in rats primed with estradiol benzoate (EB). The amount of LH release varied widely depending on (1) the interval between the time of the progesterone injection and the EB priming; (2) the progesterone dose; and (3) the time of day when blood samples were collected. These findings provided confirmation of those of Caligaris, Astrada and Taleisnik (1971a). Females, prepared with estrogen-progesterone treatment in a variety of schedules in which the three above-mentioned variables were altered systematically, were allowed to mate with vigorous males. Mating under these various conditions did not significantly increase plasma LH levels even when the females showed high degrees of sexual receptivity. Sodium pentobarbital prevented the afternoon LH rise resulting from progesterone treatment 3 days after EB priming. Pituitary sensitivity to LRF was not enhanced in the afternoon and the mating did not significantly increase plasma LH in these barbiturate-blocked rats. Following administration of 5 large daily doses of EB without progesterone, however, significant increases in LH were produced by mating on the sixth day. Postcopulatory LH release in these circumstances was dependent on a diurnal factor since the effect of mating was greater in the afternoon than in the morning. Thus, although major LH release can be readily induced by mating in estrogen-treated spayed rats, this effect could not be obtained under conditions of progesterone administration to estrogen primed rats.     

Glycosaminoglycan composition of human amniotic fluid

The glycosaminoglycan composition of human amniotic fluid between 12–21 weeks gestation has been studied by Dowex column chromatography coupled with enzymatic analyses of the specific glycosaminoglycan in each column fraction. The total uronic acid recovered from the columns consisted of “glycopeptides” (7%), hyaluronic acid (34%), nonsulfated chondroitin (14%), chondroitin-4-sulfate (13%), chondroitin-6-sulfate (20%), dermatan sulfate (5%), and heparan sulfate (6%). Based on these studies a simple screening procedure was devised to detect increased quantities of heparan sulfate and dermatan sulfate in 5–10-ml samples of amniotic fluid and tested in the antenatal diagnosis of Hurler and Hunter's syndrome. A false negative result was recorded in a Hunter fluid obtained early gestation and a false positive result recorded in a normal fluid obtained at weeks. These data suggest that the time in gestation when amniotic fluid is sampled for chemical analysis is an important variable affecting glycosaminoglycan composition in both normal and pathological pregnancies.     

Transport of O2 along a model pathway through the respiratory region of the lung

A pathway through the system of branching in the respiratory region of the lung is modelled by a circular cylinder, closed at one end, with partitions which define the component respiratory units. In this model the transport of O₂ during inspiration, generated by diffusion is compared with that produced by diffusion together with convection and the importance of convection in the respiratory region in promoting oxygen uptake at the alveolar wall is discussed. For this discussion it is only necessary to consider inspiration. The equations are solved numerically for flow rates of 10, 85 and 200 liters/min. O₂ uptake at the wall and curves of constant O₂ concentration are shown to illustrate the influence of convection. It is found that after a 2 sec inspiration from an O₂ tension of 98 mm Hg and a lung volume of 2300 ml, convection is about 12 per cent as important as diffusion at a flow rate of 85 liters/min, whereas at 10 liters/min convection is only about 0.4 per cent as important as diffusion.     

On the morphology,behaviour and systematic status of the assam macaque (Macaca assamensis McClelland, 1839)

Studies on a living and freshly dead male ofM. assamensis at Y.R.P.R.C. supplemented by notes on a living pair and their male offspring observed at the Z.S.L., enable us to supplement existing data on the somatology, craniology, dental anatomy and behavioural features of the species. Collectively the new data necessitate taxonomic revision of the status of the species, viz: its removal from immediate association withM. mulatta (subgenusMaimon) and alignment within the subgenusZati. Zoogeographical discontinuity in this subgenus is compared with that of the subgenusSilenus.     

Ultrastructure of Human labial salivary glands

Summary Human labial salivary glands, obtained by biopsy from 32 subjects, were studied by light and electron microscopy. Intranuclear inclusions, unrelated to nucleoli, were present in many of the acinar nuclei in glands from 16 of the 32 donors. More than one inclusion was sometimes observed within a single nucleus. They measured about 1 in diameter, and were stainable in a variety of ways. They were eosinophilic, some were stained by Nile blue sulphate, some were PAS-positive, and all were Feulgen-negative. They were bounded by a single membrane, which never exhibited continuity with the nuclear envelope, and they showed considerable morphological variation. The more complex inclusions consisted of alternating shells of light and dark material with tiny dense granules embedded in the latter. The intranuclear inclusions, which apparently were non-viral in origin, were in some way related to the secretory cycle of the mucous cells, since they were found only in immature cells, and never in cells in which secretory products were abundant.This work was supported in part by grants from the Henry Spenadel Trust and the Max C. Fleischmann Foundation of Nevada, by grant CA-08748 from the National Cancer Institute, by grant 5 SO1 FR 05335-07 from the National Institutes of Health, by a grant from the National Cystic Fibrosis Research Foundation, and by an Institutional Grant to the School of Dental and Oral Surgery, Columbia University, from the National Institutes of Health.The authors are indebted to Dr.Louis Mandel for performing the biopsies used in this study. The expert technical assistance of Mrs.Mona Seggio is acknowledged.