摘要:

AbstractVarious methods of ENcalcification, processing and staining have been investigated to study thin sections of human enamel. EDTA‐Na2in a phosphate buffer was found to be the ENcalcifier of choice, and a stain utilizing SnF2and H2S solutions was found to stain the sections a rich dark brown. The sections produced showed a keyhole outline of enamel rods in cross section with no eviENnce of interrod materia

ISSN:0003-276X    

DOI:10.1002/ar.1091730301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractFluorometric measurements were made of 5‐hydroxytryptamine levels in spleens obtained from separate subgroups of adult male rats killed at two‐hourly intervals over four separate 24‐hour time spans. For three weeks prior to obtaining tissue, all rats were standardized carefully and were subjected to 12 hours of light (0600–1800) followed by 12 hours of darkness. Analyses showed in each study very significant fluctuation over the 24‐hour time scale; the range of change over this period was as great as 131%. The phasing of the rhythms, in spite of the rigid environmental synchronization, was not similar in any of the four studies. Possible explanations for this unexpected desynchronization are discussed. Spleen weights also fluctuated with a significant 24‐hour circadian frequency.In addition, the rhythm characterizing this amine was described in female rats as well as the effect of different stimuli on the same rhythm. These stimuli were ether, immobilization and a ‘novelty’ situation; and all three significantly increased the levels of 5‐HT in spleen when the overall 24‐hour mean values of each experimental group were compared with controls. However, in all cases there were discrete time points when significant differences in 5‐HT levels could not be obtained with any of the stimuli. This study demonstrates that the effect of the stimuli used depends on the phase of the rat's circadian system during which it was applied. The necessity of considering the natural rhythmic fluctuation in any investigation evaluating this biogenic amine in s

ISSN:0003-276X    

DOI:10.1002/ar.1091730302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractWounds ˜ 1 mm wide were made in the middle third of the spine in both scapulae of 25 middle‐aged Wistar‐strain rats weighing ˜ 500 gm. Wounding of the body of the scapula was avoided. Some of the animals were injected with tetracycline, and sections from their scapulae were viewed in ultraviolet light. After one or more weeks of healing, bony callus was deposited on the dorsal surface of the blade of the scapulae in the vicinity of the wounds. Discrete deposits of bony callus were also deposited on the corresponding costal surface of the blade of the scapulae. These deposits, which were in no way connected with those on the dorsal surface, did not exhibit continuity with the wound in the spine. This observation has been interpreted as suggesting the passage of an ‘osteogenic message,’ whose nature can only be guessed, from the vicinity of the wound on the dorsal surface of the scapula to the corresponding costal surface. Lacunae of osteocytes in the scapulae, lying deep to periosteal and endosteal callus, fluoresced. This suggests that these osteocytes were activated by the trauma, and deposited mineral salts on the walls of thei

ISSN:0003-276X    

DOI:10.1002/ar.1091730303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractThe fine structure of the epldidymal epithelium of the rat was studied at intervals up to nine months after bilateral vasectomy, unilateral vasectomy, or a bilateral sham operation. Membranous material accumulated in the cytoplasm of the ‘light’ cells of the cauda epididymidis in greater amounts after bilateral vasectomy than following a sham operation. The membranes were found in apical vacuoles, in moderately dense membrane‐bounded bodies in the mid‐region of the cells, and, most prominently, in large infranuclear masses. These large infranuclear membranous masses had a polymorphic interior composed of granules and amorphous material as well as membranes, and thus morphologically resembled large lysosomes or residual bodies. In some instances readily dentifiable parts of sperm were found in apical vacuoles of epithelial cells after vasectomy. It is suggested that these changes may reflect the absorption of parts of sperm by the epithelium of the cauda epididymidis after vasectomy. The nature of the ‘light’ cells is discussed, and the results are compared with alterations in other species afte

ISSN:0003-276X    

DOI:10.1002/ar.1091730304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractThe swimming motion of rat epididymal spermatozoa was reexamined using high speed cinematography. Sperm were filmed at 100 frames per second and viewed at a reduced speed for detailed study. The flagella of spermatozoa from the caput epididymidis exhibit a rigid curved middle piece proximal to the cytoplasmic droplet and a flexible portion distal to the droplet. Bending waves begin at the caudal end of the immobile middle piece and propagate distally. The large majority of sperm from this region of the epididymis swim in a circular fashion, clockwise or counterclockwise, depending on the orientation of the curved midpiece. A few spermatozoa, however, manage to achieve a form of forward progression by alternation of the direction of curvature of their inflexible anterior segment. Spermatozoa from the cauda epididymidis swim progressively forward and rotate frequently about their axis of progression. Propagated waves of bending arise in the neck region and involve the midpiece as well as the more distal segments of the tail. The changing pattern of motility of sperm as they mature in the epididymis is consistent with the hypothesis, suggested by others, that the components of motility may develop independently and sequentially and further suggests that the site of initiation of bending waves is not limited to the centriole.

ISSN:0003-276X    

DOI:10.1002/ar.1091730305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractNumerous examples of partitioned mitochondria were present in cardiac muscle cells of mice, rats, guinea pigs, and canaries. The partitions, which usually bisected the mitochondria, consisted of two parallel membranes in direct continuity with the inner mitochondrial membrane. Some of these mitochondria showed varying degrees of constriction at the level of the partitions. In many partitioned organelles, the two sets of cristae on opposite sides of the septum were positioned at right angles to one another, so that if one set was seen in profile, the other appeareden face. This arrangement of cristae simplified the detection of partitioned mitochondria even at low magnifications.The number of mitochondria and the frequency of occurrence of partitioned mitochondria were considerably enhanced in heart muscle cells of some weanling mice by feeding them the copper‐chelating agent, cuprizone. The mitochondria, both with and without partitions, were identical to those in untreated animals. Based on this and other experimental evidence, and by analogy with other organs, notably mammalian liver and insect fat body, it was concluded that partitioned cardiac mitochondria are in fact dividin

ISSN:0003-276X    

DOI:10.1002/ar.1091730306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractDifferent acinar glycogen patterns are observed in rat liver after different diets. Experiments were carried out to determine if these patterns depend on the concentration of blood glucose in the various zones of the acinus or on the direction of the blood flow. It is possible to investigate this problem by reversal of blood flow in a perfusion apparatus. Livers were perfused with Krebs‐Henseleit solution, the same volume of bovine erythrocytes, and 379 mg% glucose, 2.5% albumin and different quantities of heparin. Perfusion in the normal direction is possible through the vena porta and in the reversed direction by perfusing through the vena cava. The reported results show that glycogen localization depends on the acinar enzyme pattern for glycogen synthesis rather than the direction of blood flo

ISSN:0003-276X    

DOI:10.1002/ar.1091730307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractMuscle fibers of the diaphragm and hindleg muscles of the rat were characterized bistochemically by their mitochondrial distribution (succinic dehydrogenase activity) as A, B and C (after Stein and Padykula, '62), by their myofibrillar, alkali‐stabile ATPase activity as α, β and αβ (after Samaha et al., '70), and by their acid‐stabile ATPases (intermyofibrillar and myofibrillar) as D (dark), M (moderate) and L (light). Comparisons of the differentially stained serial sections revealed profound dissimilarities between the fibers of functionally disparate muscles. The majority of fibers of the hindleg muscles were distinguishable as the conjugates AαβM, BβTD and CαL (figs. 1‐3), whereas those of the diaphragm were principally AαM, BαL and CβD (figs. 4‐6). Thus, no one histochemical reaction could accurately predict the multiple attributes of fibers of both muscle groups. Previous studies suggest that additional discrepancies in histochemical appearance would arise were other specialized muscles, e.g., extraocular muscles (Yellin, '69), compared with the more common muscles of body and limb. Any extrapolation of data on the basis of limited histochemical analyses is not without risk, whether comparing the same muscle in different species (Yellin and Guth, '70), or different muscles i

ISSN:0003-276X    

DOI:10.1002/ar.1091730308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractThe cycle of the seminiferous epithelium of the dog was divided into eight stages, using as criteria the shape of the spermatid nucleus, the location of spermatids and spermatozoa in regard to the basement membrane, the presence of meiotic figures and the release of spermatozoa from the lumen of the tubule. Based upon these criteria, a modification of the eight‐stage system of classification of the cycle of the seminiferous epithelium was developed. Cell populations making up each stage are described. The relative frequencies of stages 1 through 8 were 21.9, 12.7, 2.8, 11.5, 8.3, 15.4, 13.3 and 14.0%, respectively. The duration of one cycle of the seminiferous epithelium was 13.6 days (SE ± 0.7), as determined from cells labeled by tritiated thymidine. The absolute durations of stages 1 through 8 were 3.0, 1.7, 0.4, 1.6, 1.1, 2.1, 1.8 and 1.9 days, respectively. The life span of primary spermatocytes was 20.9 days, of secondary spermatocytes 0.5 days, spermatids with round nuclei 10.5 days, spermatids with elongated nuclei up to the time they are released into the lumen, 10.6 days. Counts of the different types of spermatogenic cells in tubular cross sections revealed little or no germ cell degeneration during the two maturation divisio

ISSN:0003-276X    

DOI:10.1002/ar.1091730309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY

摘要:

AbstractFiber‐caliber analysis of the facial nerve was made in the Japanese lesser shrew‐mole and the Japanese shrew‐mole possessing muscle spindles in the snout muscles and in the shinto shrew with no spindles. Using an enlarged photographic scale (× 250) prepared from the object‐micrometer (1/100 mm), the measurement of the fiber‐caliber was made on the enlarged photograph (× 1250) of the cross paraffin section treated with a modified myelin‐sheath staining procedure by Pettersen et al. ('70). The facial nerves of the shrew‐moles contained fibres of 1 to 10 μ in diameter, while the facial nerve of the shrew consisted of fibers of 1 to 6 μ The spectra of the former have a slight bimodality with the highest peak at 2 μ and smaller one at 6 μ. The spectrum of the latter has a unimodality with a greater peak at 2 μ. Each peak revealed a log‐normal distribution curve. Statistically, it can be said that there is a significant difference in the caliber‐spectra between the facial nerves supplying the snout muscles with muscle spindles and without spindles.For testing whether the skew of the spectrum can be the result of a truly bi‐modal distribution, the left facial nerve of the Japanese shrew‐moles was cut at the site beneath the auditory capsule. Complete degeneration of spindle innervation in the snout muscles was observed histologically in animal

ISSN:0003-276X    

DOI:10.1002/ar.1091730310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1972

数据来源: WILEY