Characteristics of the membranes of the pellicle of the ciliatePseudomicrothorax dubius

Summary The membranes of the pellicle of the ciliatePseudomicrothorax dubius are investigated using thin section electron microscopy and freeze-fracture replicas. The plasma membrane is covered by a surface coat and is connected to the outer alveolar membrane by short, sometimes branched, bridges. The inner alveolar membrane is coated on both sides. The epiplasm lies in intimate contact with the cytoplasmic surface of this membrane, and there is a corresponding deposit on the other surface. This deposit is regularly striated.The epiplasmic layer and the alveoli are interrupted at sites of cytotic activity,e.g., the attachment sites of trichocysts, the cytoproct, and the parasomal sacs. The striated deposit ends where the epiplasm ends, indicating a direct relationship between these two epimembranous layers.There is a deposit along the sides of the first part of the tip of the trichocysts, and in this region the trichocyst membrane is free of intramembranous particles.The membrane of the parasomal sacs has a coat on both surfaces. That on the extraplasmic surface is similar to the surface coat of the plasma membrane. The origin of the cytoplasmic coat is unknown. The cytotic activity of these sacs is indicated by their highly irregular profiles.     

The early development of the tail and the transformation of the shape of the nucleus of the spermatid of the domestic fowl,Gallus gallus

Summary The differentiation of the spermatid, especially in reference to the formation of the flagellum, and transformation of the shape of the nucleus was investigated in the domestic fowl.In the early stage of the spermatid, a prominent Golgi apparatus appears around the centrioles. The Golgi vesicles then surround the axial-filament complex which develops from the distal centriole. These vesicles fuse to form continuous membrane at the earliest stage of flagellar formation, and in the succeeding stage Golgi lamellae are attached to the plasma membrane of the developing flagellum. From these observations, it is assumed that Golgi apparatus may be a source of the membrane system of the flagellum.The microtubules distributed around the nucleus form the circular manchette. The anterior region of the nucleus with the manchette is cylindrical in shape and the posterior region without it remains irregular in shape. When the circular manchette has been completed, the whole nucleus acquires a slender cylindrical shape. The circular manchette then changes into the longitudinal manchette. The nuclei of spermatids without a longitudinal manchette are abnormal in shape. In view of these observations it is assumed that the nuclear shaping of the spermatid may be accomplished by circular manchette and the maintenance of shape of the elongated nucleus by longitudinal manchette.The authors wish to thank Mr. Takayuki Mori for his helpful suggestions and technical advices     

Observations on the permeability of the choriocapillaris of the eye

Summary The choriocapillaris is a fenestrated capillary bed located posterior to the retinal pigment epithelium. It serves as the main source of supply to the photoreceptors, retinal pigment epithelium, and other cells of the outer retina. The permeability of these capillaries to intravenously injected ferritin (MW — approx. 480,000; mol. diam. 11 nm) was examined in the mouse, rabbit, and guinea pig, each of which is characterized by a different type of retinal vascularization. In all three species, the bulk of the ferritin remained in the capillary lumina, where it appeared to be blocked at the level of the diaphragmed fenestrae. Some ferritin was present in endothelial cell vacuoles. The results confirm previous work on the rat choriocapillaris and indicate that the barrier function of the choriocapillary endothelium is present even among species in which the retinal circulation differs significantly.Supported by NIH grant EY03418     

Separation of the pineal vesicle from the wall of the third ventricle during the post-hatching development of the chicken

Summary According to light- and electron-microscopic observations the pineal organ of the 3-day-old chicken consists of a prominent end vesicle and a tapering parenchymal stalk. During this stage the pineal lumen is in open communication with the third ventricle. However, in the 40-day-old chicken, which still possesses a well-developed end vesicle, the proximal portion of the pineal stalk displays regressive changes leading to local fragmentation. At this stage the pineal stalk is reduced, and the pineal lumen is missing. In 1-year-old chickens the parenchyma of the proximal portion of the stalk is further diminished, and in 3-year-old domestic fowl is completely displaced by bundles of collagenous fibers, only some nerve fibers being present. This post-hatching pineal development may reflect the sequence of changes leading from pineal sense organs to pineal glands.This work was supported by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan     

Analysis of the intra-individual differences of the joint surfaces of the calcaneus

Patients with calcaneus fractures experience considerable interferences with daily living activities. The quality of anatomical reconstruction is important because of its influence on functional outcome. The aim of this study was to develop an automatic algorithm based on computer tomographic (CT) images to quantify the integrity of calcaneal joint surfaces. Validation of this algorithm was done by assessing intra-individual variations of characteristic joint parameters. Bilateral hind foot CT data of 12 subjects were manually segmented, and 3D models from the calcaneus, talus and cuboid were generated. These models were implemented in a custom-made software to analyse the area, 3D orientations and bone distance of the joint surfaces of the calcaneus. Three joints were detected, and the calculated parameters were compared between right and left hind foot by the evaluation of the directional asymmetry (%DA). The results were statistically analysed with a paired t-test. The median of area (5–7 %DA) of the joint surfaces and the distance between two articulating surfaces (8–9 %DA) showed the greatest intra-individual differences. Median differences in 3D orientation were comparatively low (1–2 %DA). None of these differences was statistically significant. Inter-individual variations among subjects were several magnitudes larger than intra-individual differences. The presented computational tool provides 3D joint-specific parameters of the calcaneus, which enable to describe their respective joint integrity. The results show that only small intra-individual differences within the anatomy exist. Surgical treatment should take place with the aid of CT data from the contralateral side. Thus, a good restoration of the anatomy may be reached. The computational tool assesses the quality of reduction, and may be helpful to evaluate the outcome and quality of operative treatment based on the calculated joint-specific parameters of joint reconstructions in the hind foot.     

Characterization of the composition of the aqueous humor and the vitreous body of the eye of the frog Rana temporaria L

This study aimed to analyze the aqueous humor (AH) and the vitreous body (VB) of the eye of the adult frog Rana temporaria L. as a representative species of amphibians, which lead a semi-terrestrial life. The presence of collagen, albumin, uric acid and electron donors was shown in both media; however, there are slight differences in their concentrations. To determine collagen, a spectral-fluorescent probe, cyanine dye, was used. The presence of collagen in AH of the frog was found at the first time. The total content of electron donors (ascorbic and uric acids, tryptophan, and tyrosine) in VB and HA was roughly estimated at ~ 1.5 × 10^− 4 mol/L. Both VB and AH absorb light in similar UV regions. The total protein and albumin contents in AH were found to be somewhat higher than those in VB. The uric acid content was at an equally low level in both intraocular media. It is supposed that the similarity of VB and AH compositions shown in this work is due to some exchange between VB and AH contents in the course of accommodation. The role of intraocular fluids in physiological functions of the eye and in protecting the retina against UV light is discussed.     

A conspectus of the Cladocera of the subterranean waters of the world

A synthesis of current knowledge of the Cladocera living in non-surface waters is provided. For all 94 species and subspecies recorded (Dec. 1994) we give information on their ranges, ecological characteristics, and a review of literature data. We also give a historic survey of the development of concepts, identify categories among groundwater-dwelling species, and discuss their adaptations and the evolutionary lines present. Of the estimated total of c. 450 non-marine Cladocera of the world, c. 20% may occur in underground aquatic habitats, but true groundwater forms (stygobionts or stygobites) are relatively few, possibly not more than 10 species (c. 2.5% of the total). This number may increase, as attention is given to subterranean habitats outside Europe.     

Topography of the contours of the inner surface of the wall of the left ventricle of the heart in systole

Chosen at random 38 diastolic preparations of human hearts from persons having not any cardiac pathology, as demonstrate the postmortem examination, have been investigated. The left ventricle casts have been made during the first 24 hours after death according to a strictly fixed technique by means of filling the cardiac chambers with polymere mass--protacryl--under a physiological pressure of the diastolic filling. The trabecules are arranged as a spiral from the apex of the ventricle up to the atrioventricular fibrous ring, with approaching the apex the spiral step increases and the trabecules straighten. The left ventricle cast is devided into some planes, the envelopes and the trabecularity lines are measured. Average values of the shift in the trabecularity lines I, II, III and in the cross sections B, C, D, E are defined in relation to the plane A and in every case in relation to the previous plane Cn-1. The data obtained are presented in tables and diagrams. The greatest shift demonstrate the trabecularity lines I running predominantly along the posterior wall of the left ventricle in the planes B and which are situated nearer to the atrioventricular ring projection. Owing to the presence of the spiral-shaped course of the trabecules, it is possible to suppose that it influences the blood stream twisting clockwise in the left ventricle during the diastole phase. This indicates the necessity to work out some new constructions of artificial cardiac valves, securing the twisted blood stream. The condition mentioned should be taken into consideration while making prostheses of the cardiac valves.     

Forms of the Word and the Mystery of the Objectified Nature of the Word

The time has come to proceed from forms of givenness of the word to forms of the word as such. They can, if you like, be called external and inner structures. Humboldt, however, preferred to speak of the external and inner forms of the language. Shpet adopted precisely this distinction. Why did this problem interest Shpet? Already in [Appearance and sense], he had set the task of returning to the source of pretheoretical, living science. Shpet wrote that the outer cover of words and logical expressions obscure the objectified meaning and that it was necessary to remove another cover from the objectified sign so as to grasp a certain genuine intimacy, and in it the fullness of being (Shpet, 1914. Pp. 5-6). We shall keep in mind this major undertaking posed by this scientist. The existence of the inner form of words should not come as a surprise. That same year (1914) Ortega y Gasset wrote that material objects have a third dimension. However, we cannot see or touch it: "For just as depth needs a surface beneath which to be concealed, the surface, or outer cover, in order to be so, needs something over which to spread, covering it" (Ortega y Gasset, 2000. Pp. 62-63).