摘要:

The principle of antagonistic compensation was presented by Riesenfeld in 1966 to explain the relative shortening and broadening of hypofunctional bones. Few studies have concerned themselves with this phenomenon, even though the causative agent(s) have not been delineated. In his study, Riesenfeld induced the hypofunction by complete unilateral and bilateral forelimb amputation. The resulting hypofunctional condition may be attributed to the lack of muscle function or to the lack of weight bearing or both in combination. In the present study weight bearing was eliminated in such a manner as to preserve muscle functioning. This was accomplished by two techniques: (1) unilateral forearm amputation and (2) unilateral humeral resection. Statistically significant differences in interindividual scapular length and breadth as well as humeral and ulnar lengths are reported. In all cases, the bones of the operated side were shorter than those of the unoperated side and the scapular breadth of the unoperated side was relatively greater. This confirms the hypothesis that weight bearing is, at least, partially responsible for the morphological changes induced by hypofunction and described by the principle of antagonistic compensation. However, as the reduction in length was of a lesser magnitude than that reported by Riesenfeld, the input of muscle function cannot be ignored. Rather, as both muscle functioning and weight bearing induce compressive force on long bones (including the scapula), both may serve to initiate the observed morphological changes through the vehicle of reduced compression.

ISSN:1422-6405    

DOI:10.1159/000144597

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

(1) Data on the embryonic growth of several organs and of many different types of tissue in the mouse and rat are presented. (2) The concept developmental age is introduced, because it leads to an age estimate that is better correlated with the developmental stage. (3) The general growth pattern of the organs and tissues studied agrees with that found for the whole animal, consisting of phases with exponential growth separated by breaks. In the majority of the organs the breaks occur at the same time as in the whole animal. (4) The decrease in the growth rate at the end of phase EII is definitely smaller in the majority of the organs than in the whole animal. (5) Breaks occurring at other times than those found in the whole animal seem to take place in a few organs, and in the mouse at the embryonic age of about 17 days in a large number of organs.

ISSN:1422-6405    

DOI:10.1159/000144598

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

3 and 5 days following intravenous injection of 6-OHDA (100 mg/kg) in adult rats, the Nauta technique demonstrated sparse axon degeneration in laminae V, VII, IX and X of Rexed in the mid-thoracic spinal cord and also in the lateral and ventral white columns. This showed that in adult rats 6-OHDA may pass the blood-brain barrier at the level of the spinal cord. An unexpected finding was the absence of degeneration in the laminae dorsal to lamina V, where noradrenergic nerve terminals are known to occur.

ISSN:1422-6405    

DOI:10.1159/000144599

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

The effects of the long-acting prostaglandin Ax upon pregnancy and fetal development were investigated in Long-Evans rats. The animals were treated by the intra-uterine route either on gestational day 14 with 25 μg PGA1 or with 50 μg on day 17 of gestation. The incidence of fetal resorptions was significantly increased compared to the controls following treatment on gestational day 17. A significantly high incidence of nonspecific malformations was also induced in the offspring as a result of the treatment. There were no significant differences between experimental and control fetal and placental weights. The total protein content of fetal liver following treatment with PGA1 was not significantly reduced. Microscopic examination of placentas showed a consistent decrease in the thickness of the decidua basalis following treatment with 25 μg PGA1 on day 14 of gestation. The ovaries and umbilical cords showed no changes. In addition, treatment of rats daily with 200 μg PGA1, administered subcutaneously, on gestational days 9–12 or 12–15 did not affect the development of the conc

ISSN:1422-6405    

DOI:10.1159/000144600

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Chronic administration of α-chlorhydrin caused lesions of rat, gerbil and bat testicles selectively. The seminiferous epithelium became systematically depleted of spermatogenic elements. α-Chlorhydrin did not produce lesion of the caput epididymidis. Sloughing of the epithelial lining did not occur. No obstruction of the lumen of the epididymal duct was seen. The growth of androgen-dependent organs, i.e. seminal vesicles, epididymis and levator ani muscles was suppressed. α-Chlorhydrin caused no response directly on the epididymides. Subcutaneous or oral administration of α-chlorhydrin for a period of 3–5 weeks caused no response in the testes and epididymides of the

ISSN:1422-6405    

DOI:10.1159/000144601

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Malononitrile dimer was administered to mice by single or by chronic (40 day) injections. The concentration of RNA in neurons of the brain was determined on histological sections by means of azure B staining. The nucleolus and Nissl substance of the several types of large neurons studied had a significantly higher concentration of RNA in the drug-injected than in the control animals.

ISSN:1422-6405    

DOI:10.1159/000144602

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

The trophoblast giant cells of the mouse placenta are mitotically inactive. Nucleolar RNA synthesis is apparently at a standstill. The high nuclear DNA contents of these cells shown by 3H-thymidine marking is conceived by us to be a synthesis of metabolic nuclear DNA. Thus protein synthesis in trophoblast giant cells has been taken over by a metabolic DNA.

ISSN:1422-6405    

DOI:10.1159/000144603

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

A fine-structure study of the hamster fungiform, foliate and vallate taste buds was undertaken for comparative purposes. All three taste bud types shared in common composition of the dark cells, light cells, basal cells, nerve fibers and nerve endings and undifferentiated peripheral cells, but morphological difference existed among them. The foliate and vallate taste buds were quite similar in their ultrastructural morphol ogy. Their dark cells displayed long apical necks, long apical microvilli, apical osmiophilic secretory granules and an abundant rough endoplasmic reticulum. The dark cells of the fungiform taste buds, however, showed no neck formation and lacked apical osmiophilic granules. They had short apical microvilli and relatively scant rough endoplasmic reticulum. There was no difference in the fine structure features of the light cells, basal cells and neural elements of different types of taste buds. Both light and dark cells were much more readily distinguishable in foliate and vallate buds than in fungiform buds at both light- and electron-microscopic levels. Foliate and vallate buds demonstrated homogeneous dense substance within the taste pores while fungiform pores were frequently empty. It is speculated that the differences in taste bud morphology may be due to their different lingual locations and/or may be a reflection of the differences in the inductive influences from different nerves. Furthermore, structural differences may be responsible for varying thresholds to different taste modalities.

ISSN:1422-6405    

DOI:10.1159/000144604

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Intramuscular administration of crystalline mammalian glucagon (0.5–2.0 mg/kg body weight) evokes significant cytological alterations in the principal islets of Channa punctatus, a fresh-water fish. Initially there is degeneration of the α-cells but later the /5-cells are also atrophied. Regressive changes in some of the α-cells have been interpreted to reflect their possible role in glucagon secretion. The degeneration of β-cells appears to be secondary to the fluctuations in the blood glucose level, induced by exogenous gluc

ISSN:1422-6405    

DOI:10.1159/000144605

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

The work is devoted to the study of the structure of the innervation apparatus of taste buds in the epiglottis of monkeys (Macacus rhesus). The Campos impregnation method was used. It is established that several afferent myelinated fibers participate in the innervation of each taste bud of the epiglottis. The peculiarity of structure of their pre-terminal and terminal parts having the appearance of complex windings and spirals is noted. The polyaxonic principle of the innervation of taste buds of the epiglottis in monkeys is considered as a possible mechanism of generalization of the afferent impulses. It is suggested that the innervation apparatus of the taste buds of the epiglottis constitutes part of unique afferent system of this organ, ensuring its defensive function. The incongruity (from the histophysiological standpoint) of the term ‘taste bud’ in relation to the epiglottis is noted. It is proposed to call these formations special structures of the chemo-recept

ISSN:1422-6405    

DOI:10.1159/000144606

出版商:S. Karger AG    

年代:1976

数据来源: Karger