Histology and histopathology Vol. 7, nº 3 (1992)
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- PublicationOpen AccessScanning electron microscopic and light microscopic observations on morphological changes of freeze-dried bone implantation in rats(Murcia : F. Hernández, 1992) Matsuda, Mikio; Satoh, Y.; Ono, K.Bone remodelling after the implantation of freeze-dried autogenous bone in rat parietal bone was compared with fresh autogenous bone transplantation, using a scanning electron and light microscope revealed the time intervals after transplantationfimplantation. The light microscope revealed the time delay of the bone remodelling in the implantation, compared with the transplantations. The scanning electron microscope showed that the differences between the two groups were in the states of bone union and bone resorption. In the fresh bone group, the newly-formed bone filled the spaces between host and the transplanted bones at 2 to 3 weeks after the transplantation: the newly-formed bone fused and melted into the transplanted bone. New bone formation was more dominant on the bone surface in the dura mater side than in the skin side. The union was almost completed at 5 weeks. In freeze-dried bone implantation, the bone union in the contact space was very poor and the implanted bone was mainly covered by the new bone, which developed from the host bone surface in the dura mater side at 2 to 3 weeks after the implantation. What is noteworthy is that bone resorbed areas showing numerous Howship's lacunae were mainly observed on the host bone surface in the vicinity of newly-formed bone. However in freeze-dried bone implantation, the bone resorption was greater on the host and implanted bone surface than that of fresh bone transplantation: the resorption of host bone was considerably larger at certain periods after freeze-dried bone implantation. The present results show that the healing process of freeze-dried bone implantation, even though autogenous bone was used, differed from that of fresh autogenous bone transplantation, and the differences are concerned not only with time sequences but also with qualitative changes. This suggests that the host would have some different responses to the freeze-dried autogenous bone from fresh materials.
- PublicationOpen AccessDistribution of neuropeptide Y-like immunoreactivity in the brain of Salmo salar and Gambusia affinis(Murcia : F. Hernández, 1992) García-Fernández, J.M.; Del Brío, M.A.; Cernuda-Cernuda, R.; Coto, A.; Riera, P.Through the imrnunohistochernical PAP technique, the distribution of irnrnune positive neurons and fibres for an antibody anti-NPY in the encephalon of salrnon fixed in Bouin have been located and studied. NPY-positive neurons are found forming three important nuclei: in the ventrolateral telencephalon; in the tegmentum mesencephali; and in the locus coemleus. Neurons in the optic tecturn, in the thalarnic region and a few in the preoptic recess have also been located. The fibres were found throughout the brain, with the exception of the cerebellurn, presenting a greater density in three regions: in the dorsal telencephalon; in the mesencephalon; and in the visceral lobes in the rhombencephalon. With the airn of proving if this distribution is found in other groups of teleosts, we processed, with the sarne technique, the advanced teleost Gambusia affinis, in order to compare it with the prirnitive teleost Salmo salar. The results show that in both fish this neuropeptide has the same pattem of distribution. The results also suggest that in fish this neuropeptide can be involved in severa1 functions of the central nervous systern, as has been dernonstrated for rnarnmals. The innervation of the visceral lobes and also the presence of NPY-fibres in the posterior hypothalarnus are anatornical supports of the studies which suggest that NPY is related to the control of the food intake.
- PublicationOpen AccessMorphometric studies on the development of human thyroid gland in early fetal life(Murcia : F. Hernández, 1992) Bocian-Sobkowska, J.; Malendowicz, L.K.; Woíniak, W.Histological and morphometric studies were performed on 30 thyroid glands obtained from normal human fetuses. Their crown-rump length (CRL) ranged from 57 to 190 mm, corresponding to the gestational age of 10 - 20 weeks. The weight of the thyroid gland increased proportionally in relation to CRL, foot length and fetus weight. The first follicles containing PAS-positive colloid were observed in the peripheral part of the thyroid gland of 57 mm CRL fetus. The number of follicles per 1 mm2 of thyroid surface section increased up to 85 mm CRL and thereafter gradually declined for the end of studied period of fetal life. The volumes (in mm3) of thyroid epithelium, colloid and stroma, beginning from 85 mm increased proportionally to the CRL while the height of epithelial cells did not change. The epithelium/colloid ratio decreased notably to 165 mm CRL and thereafter remained constant. Results of the present study suggest that the thyroid gland of human fetus approaches structural maturity in 17.5 week of gestation.
- PublicationOpen AccessRetinal pigment epithelial fine structure in the red-backed salamander (Plethodon cinereus)(Murcia : F. Hernández, 1992) Braekevelt, Charlie R.The retinal pigment epithelium (RPE) of the red-backed salamander (Plethodon cinerus) consists of a single layer of large squamous shaped cells. The RPE cells are but minimally infolded basally (sclerally) but show many large apical (vitreal) processes interdigitating with the rod outer segments. These epithelial cells are joined laterally by prominent tight junctions located in the mid region of the cells. Internally smooth endoplasmic reticulum is very plentiful while rough endoplasmic reticulum is not. Polysomes, small dense mitochondria and small round to oval melanosomes are plentiful. Golgi zones and lysosome-like bodies are also present as are phagosomes of outer segment material and myeloid bodies. The RPE cell nucleus is large and vesicular. It is felt that the melanosomes undergo retinomotor movements but as only light-adapted specimens were examined it is not known how extensive are these movements. Bruch's membrane or complexus basalis shows the typical pentalaminate structure noted for most vertebrates. The choriocapillaris is a single layer of large anastomosing capillaries which are minimally fenestrated facing Bruch's membrane.
- PublicationOpen AccessRetinal photoreceptor fine structure in the red-backed salamander (Plethodon cinereus)(Murcia : F. Hernández, 1992) Braekevelt, Charlie R.The retinal photoreceptors of the red-backed salamander (Plethodon cinerus) have been studied by light and electron microscopy. Rods and single cones are present in this duplex retina in a ratio of about 25: 1. The photoreceptors in this amphibian species are much larger than is reported for most vertebrates. In the light-adapted state, rods reach deep into the retinal epithelial (RPE) layer. The rod outer segment is composed of discs of uniform diameter displaying severa1 very deep incisors. The rod inner segment displays a dista1 elliposid of mitochondria and a short stout myoid region. Rod nuclei are electron dense and often protrude through the extemal limiting membrane. Rod synaptic spherules are large and display severa1 invaginated synaptic sites as well as superficial synapses. It is felt that the rods do not undergo retinomotor movements. The cone photoreceptors are much smaller than the rods and display a tapering outer segment, an unusual modified ellipsoid and a large parabolid of glycogen in the inner segment. Cone nuclei are less electron dense than rods and are located at al1 levels within the outer nuclear layer. The synaptic pedicle of the cones is larger, more electron lucent and display more synaptic sites (both invaginated and superficial) than that of rods. It is felt that cone photomechanical responses are minimal.