摘要:

Regarding maxillofacial morphogenesis there has been a long debate on the growth of the maxillary structure. Using 120 normal fetal maxillae of gestational ages from 16 to 41 weeks, palatal radiograms and frontal histologic sections were made. We have observed two pairs of accentuated growth areas in the fetal maxillae and named them primary growth centers to formulate the maxillary trapezoid (MT) by radiologic image. The MT is formed by four primary growth centers that are best demonstrated by palatal radiograms of the fetal maxilla as well as by frontal histologic sections. The dimensional increase in the MT during the fetal period is documented and statistically analyzed. From this series of results, we have suggested that the growth centers which demarcate the MT are the basic structures of the developing human maxilla. It was also found that the four primary growth centers are the most active sites for maxilla formation until 20 weeks of gestation and thereafter the growth of the maxilla is enhanced by the participation of the intramembranous bone formation along the periphery. This was in contrast to the central primary growth centers that have already finished maturation in the early fetal period and remain only as a peripherally radiating arrangement of thick trabecular bones.

ISSN:1422-6405    

DOI:10.1159/000147334

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

During the course of root formation, histologic examinations show many pictures; however, the last stage of root formation is not well documented. In this paper, we describe cellular and extracellular components of immature teeth with incompletely formed roots. The odontoblast cells were observed with reticular fibers. The cementoblasts and epithelial cells covered the cementoid tissue. The results are discussed.

ISSN:1422-6405    

DOI:10.1159/000147335

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Afferents to the fetal rat cerebellum have been studied in fixed tissue with the fluorescent tracer, 1,1’-dioctadecyl-3,3,3’,3’tetramethylindocarbocyanine perchlorate (DiI). The dye was applied to the cerebellar anlage at ages from embryonic day (E) 12 to birth (PO). Central processes of vestibular ganglion cells were found to be the first identifiable afferents to the cerebellum, being present at least by E13 and perhaps as early as E12. Ipsilateral spinocerebellar fibres may be labelled from E15, vestibular nuclei (both ipsi- and contralateral) also from E15, while contralateral inferior olivary nuclei could not be retrogradely labelled until E17. Trigeminocerebellar neurons in the interpolaris subnucleus of the nucleus of the trigeminal spinal tract and neurons of the lateral reticular nucleus were not labelled until E22 and P0, respectively. Finally, contralateral pontine nuclei were retrogradely labelled from the cerebellum after

ISSN:1422-6405    

DOI:10.1159/000147336

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The findings of the histological study of the human temporomandibular joint confirm that the cranium and the lower jaw are joined by two temporomandibular articular complexes (one on the left and another on the right side), each made up, in turn, of two joints – a condylomeniscal condyloarthrosis and a reciprocally fitting meniscotemporal joint. Both these joints are surrounded by short capsular bands which stretch from the condyle to the meniscus and from the latter to the temporal bone and form the true joint capsules. Longer bands which extend from the condyle to the temporal bone may be regarded as reinforcements passing over two articulation

ISSN:1422-6405    

DOI:10.1159/000147337

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Methods of morphological, histochemical and immunohistochemical analyses were used to further characterize differences between tumorous and adjacent grossly normal tissues in chemically-induced colon cancer in rats. Colon tumors were induced by the treatment of rats with 1,2-dimethylhydrazine or with N-methyl-N’-nitro-N-nitrosoguanidine alone or with subsequent treatment with deoxycholic bile acid. Tissues were studied morphologically (for the presence of goblet cells in the colon crypts, and the extent of infiltration of lymphocytes into the crypts and between them) histochemically (for the presence of positive reaction to neutral and acid mucopolysaccharides) and immunohistochemically (for the presence of tissue polypeptide antigen). All data were evaluated quantitatively, and index of tissue damage was calculated for both tumorous and non-tumorous tissues. Significant morphological differences were found between tumorous and adjacent apparently normal tissue. Histochemically and immunohistochemically, both types of tissue reacted very similarly to exposure to the carcinogens. Index of damage was significantly different from normal untreated colon in both kinds of tissue. It was suggested that precancerous state in tissue adjacent-to-tumor could be detected using the combination of these method

ISSN:1422-6405    

DOI:10.1159/000147338

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The morphology of the pectoralis major muscle and its antagonist, the supracoracoideus muscle, of the Chinese quail was studied in comparison with the Japanese quail, in relation to behaviourial characteristics. The actomyosin ATPase reaction after alkaline and acid preincubation reveals two fibre types. The indirect immunofluorescence, using specific antibodies against ‘slow’ (twitch) myosin from the human vastus lateralis muscle, provokes a weak reaction. All fibres observed show focal, monoaxonal ‘en plaques’ endings, typical of the phasic motor system. For the two quail species, the muscle structure seems adequate in relation to the movement characteristics, meaning muscle activity of migratorys, flying long di

ISSN:1422-6405    

DOI:10.1159/000147339

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The thenar and hypothenar muscles as well as their supplying nerves were analyzed with an improved dissecting method. Among the four thenar muscles, the m. abductor pollicis brevis (AbPB) has a separate muscle belly, whereas the m. opponens pollicis (OP), the superficial and deep heads of the flexor pollicis brevis (sFPB and dFPB), and the adductor pollicis (AdP) are fused with each other to make a single mass (deep thenar muscle group). These muscles are innervated by branches of the recurrent nerve and the accessory recurrent nerve from the median nerve as well as by terminal branches of the deep branch (ramus profundus) of the ulnar nerve. These three nerves frequently form a loop within the deep thenar muscle group (thenar loop), and a branch to the OP and one to deep parts of the sFPB often make a smaller loop (intrathenar loop) whereas the AbPB receives a separate nerve branch. Among the hypothenar muscle, the m. abductor digiti minimi and the m. flexor digiti minimi brevis are fused with each other, and their supplying nerves frequently form a loop in these muscles (intrahypothenar loop), whereas the m. opponens digiti minimi is separated from the others and receives a separate nerve branch. In the distribution pattern of supplying nerves to the thenar and hypothenar muscles, we find regularities in that they branch off in a regular manner from the ulnar and the median nerve, and that nerve branches to those muscles with fused bellies frequently communicate with each other to make loops.

ISSN:1422-6405    

DOI:10.1159/000147340

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Using the histochemical stains aluminon, solochrome azurine and solochrome cyanine, intracellular binding of aluminium was examined in the mucosa of the stomach, duodenum, jejunum and ileum of adult rats. A first group of rats (n = 42) was sacrificed 1, 3, 6, 12, 24, 48 and 96 h after a single (300 mg × kg–1) oral administration of aluminium hydroxide. A second group of animals (n = 30) received daily the same dose of Al(OH)3 and was euthanatized after 3, 4, 5, 6 and 7 days of treatment. Aluminium deposits occurred only in the antral glands of the stomach and in rats treated for at least 3 days. The reactive deposits are located in the cytoplasm of the upper glandular cells and in the lumen of the antral glands. These results suggest that aluminium is absorbed through the antral mucosa and may be re-excreted through the glandular mucus flow into the digestive lumen where it will be absorbed again. We hypothesize that the metal could act as a delayed-effect dr

ISSN:1422-6405    

DOI:10.1159/000147341

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

In this study, a detailed examination of the distribution of the cochlear artery (branch of the labyrinthine artery) together with an investigation into whether or not another artery contributes to the supply of the cochlea were carried out, and the results were compared with the findings of similar studies.

ISSN:1422-6405    

DOI:10.1159/000147342

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Glucocorticoids may induce osteopenia in experimental animals and in man. In order to study the possible effects of vitamin D metabolites in the prevention of glucocorticoid-induced osteopenia in rats, we administered 1α(OH)-vitamin D3, 24,25(OH)2-vitamin D3 or a combination of both metabolites, by intragastric intubation, to rats treated daily by intramuscular injections of 10 mg/kg cortisone acetate. Treatment with the vitamin D metabolites started after 1 month of glucocorticoid therapy, at the time osteopenia was already present. Cortisone acetate decreased the gain weight, increased alkaline phosphatase (AP) and decreased Ca serum levels. It also decreased tibial wet and ash weight and tibial Ca content. Computerized histomorphometry of sections from the upper tibia showed decreased epiphyseal bone volume and increased bone marrow volume; decreased height of hypertrophic cartilage in the growth plate and decreased amount of persisting cartilage in the metaphyseal bone trabeculae were also observed. Administration of 24,25(OH)2D3 alone did not reduce these glucocorticoid-induced bone changes and sometimes even worsened them. 1α(OH)D3 reversed many of the deleterious effects of cortisone acetate. It reduced serum AP levels, increased serum Ca levels, increased bone ash weight, epiphyseal and metaphyseal bone volume, with a concomitant reduction in epiphyseal and metaphyseal bone marrow volume. The best results were obtained by a combination of 1α(OH)D3 and 24,25(OH)2D3. It is presumed that both metabolites are needed to reduce the impact of glucocorticoids on bone. 1α(OH)2D3 acts on the gut, increasing Ca absorption (which was decreased by glucocorticoids), and 24,25(OH)2D3 directly acts on bone to enhance bone formation and mineralizat

ISSN:1422-6405    

DOI:10.1159/000147343

出版商:S. Karger AG    

年代:1992

数据来源: Karger