Breast tumor developed in a pregnant rat after treatment with the teratogen Cycloheximide.

AIM: To describe histochemically and immunohistochemically a breast tumor presented in a pregnant rat given Cycloheximide to examine its teratogenic and embryotoxic effect on the embryos. METHODS: Cycloheximide was injected in pregnant Wistar rats at a dose of 3 mg/kg.b.w. on both 10th and 11th gestational days. In one of the rats, a large breast tumor developed rapidly. Histochemical staining with Hematoxylin-Eosin and Masson Trichrome and immunohistochemical identification with mouse monoclonal antibodies: a) Estrogen Receptor A and b) Estrogen Receptor B was performed. RESULTS: Analysis with A-receptor and B-receptor showed that the breast tumor which was developed after treatment with Cycloheximide was malignant. Positive immunohistochemical reaction was evident especially with A-receptor indicating the malignancy of the tumor. CONCLUSIONS: Cycloheximide is a known toxic and teratogenic agent and potentially a carcinogenic drug. Thus it should be used with extreme caution as a pesticide.

[Postoperative deposits on a second-generation silicone lens]. / Postoperative Eintrübungen einer Silikonlinse zweiter Generation.

BACKGROUND: In the literature there have often been reports about deposits (hydroxyapatite) in hydrophilic or hydrophobic intraocular lenses (IOLs). We report, for the first time, about deposits on a silicone IOL of the second generation. MATERIALS AND METHODS: A silicone IOL (Allergan, type SI-40) which was extracted due to gradual visual loss, has been examined. RESULTS: The examination with the scanning electron microscope (SEM) showed crystalline precipitations in the anterior surface of the IOL while the X-ray analysis showed the existence of calcium and carbon, whereas no phosphorus was found. CONCLUSIONS: It could be hypothesised that metabolic disorders in aqueous humor (i. e., in patients with diabetes mellitus), the quality of the production of the lens, and not the IOL material, are the main cause for deposits in the IOL surface.

Dense-cored vesicles in human dental macrophage-like pulpal cells.

In the human dental pulp of five healthy premolars, we detected the presence of vesicles in the cytoplasm of macrophage-like cells. There were, in general, two types of vesicles, with regard to their size and content. The first was of smaller size (35 to 55 nm), and they were electron optically empty. The second type included larger vesicles (100 to 150 nm) presenting a heavily and homogeneously osmiophilic dense core. Their overall morphology was strikingly similar to the well-known, dense-cored vesicles of the sympathetic and neuroendocrine systems. This morphological evidence may be considered as an adjunctive support for the neural crest derivation of the dental pulp.

Pathogenesis of bromodeoxyuridine-induced cleft palate in mice.

This study was designed to examine the pathogenesis of bromodeoxyuridine-induced (BrdU) clefts of the secondary palate in mice. Intraperitoneal injections of BrdU (500 mg/kg body weight) were given on days 11 and 12 to some pregnant mice and on days 12 and 13, and days 11, 12 and 13 to others. Evaluation of craniofacial relations and palate development in BrdU-treated mice revealed inhibition of vertical development of the palatal shelves, mandibular hypoplasia which led to failure of downward displacement of the tongue and the creation of an obstacle to reorientation of the palatal shelves. The results of this study demonstrate a strong correlation between induction of cleft palate and the presence of structural alterations in the mandible, and the mechanism of BrdU-induced cleft palate resembles the defect in the Pierre Robin anomaly.

Computerized reconstruction of TEM examined pulpal blood vessels and nerves.

Five healthy premolars were used for transmission electron microscopy examination and three-dimensional (3D) reconstruction of pulpal blood vessels and their surrounding nerves. Serial Epon thin sections were taken from specimens. After a series of preprocessing steps that included digitization, contrast enhancement, slice alignment, segmentation and interpolation, three dimensional surface representation was performed using the triangulation method. The findings showed that vessels were usually accompanied by a number of myelinated and unmyelinated nerves. The nerves shared a more or less common course with the vessels. Small arteries presented greater number of nerves in their vicinity, compared to small veins. In the sections examined, no direct contact between the nerve trunks and the wall of the vessels was found; the closest distance measured was approximately 67 microns. The common course of vessels and nerves suggested autonomic innervation on part of the myelinated axons.

Ultrastructural alterations of the rabbit sciatic nerve, spinal cord and cerebellum, following methionine sulphoximine administration.

Methionine sulphoximine (MSO) is a centrally acting neurotoxin which inhibits the glutamate metabolism enzymes and has convulsive properties. Small doses of MSO were administered to rabbits, either intravenously (i.v.) or intracerebroventricularly (ICV), and electron microscopic examination of the cerebellum, the spinal cord and the sciatic nerve was performed on the first day of rabbit hind leg rigid paralysis (myopathy with histological findings resembling myositis), which set in by the 2nd to 4th day after MSO administration. In the cerebellum focal minor alterations were found in the astrocytes (swelling and lucidity, diminution of glycogen granules) and sparsely in the presynaptic terminals (lucidity and clumping), whereas most of the neuron presented a normal appearance. In the spinal cord and in the sciatic nerve a dissociation of the axon from the myelin sheath was evident in a small number of myelinated nerve fibres, along with the appearance of vacuolated spaces. Mitochondrial disorganisation in the axons, as well as glial cell alterations, were also seen. The ultrastructural alterations were non specific, and since they were induced 2 to 4 days after the administration of either minimum doses (i.v.) or of extremely low doses (ICV) of MSO, they may be attributed to the inordinate increase of metabolism during the period of convulsions.

Ultrastructural alterations of the rat intestinal epithelium fed with polymeric, oligopeptidic or elementary full diet, following starvation.

In this study the ultrastructure of rat jejunal epithelial cells was examined, following a starvation period of 72 hours and an enteral refeeding period of 12 days, with either Nutrison, Pepti 2000, or Nutri 2000. Most changes occurred in the animals examined immediately after the 72-hour starvation period; these mainly included a significant decrease in microvilli population, occasional cell membrane disintegration, and a usual microvesicular appearance and degranulation of the rough endoplasmic reticulum. No alterations were found in the normally-fed animals (control group). This was also practically the same for the Pepti 2000 group. In the Nutrison group, a small amount of changes were found, while in the Nutri 2000 group many alterations were detected, which nevertheless were fewer than in the starved animals. The results demonstrate that the micromorphological alterations of the intestinal epithelium caused by starvation improve faster when an oligopeptidic formula is provided, which consequently results in faster and better absorption of the nutrients.

Pinocytotic vacuoles in human dental pulp capillaries.

Dental pulp capillaries were studied in human. They were of the continuous type, with the exception of a small number which were of the fenestrated type, located in the vicinity of the odontoblasts. A characteristic morphological peculiarity was found in the endothelial cells. In places there was a large quantity of multi-sized vacuoles. The vacuoles were evidently of pinocytotic origin, and their content was emptied into the extracapillary space. The initiation of their formation was indicated by the creation of cytoplasmic flaps, which could not be characterised as typical pseudopodia, and which in cross sections resembled microvilli. The flaps engulfed a quantity of plasma and then, after bending over, their edge fused with the cell, creating a vacuole. The vacuole, after being moved abluminally, was emptied into the pericapillary area by exocytosis. There was indication that flaps created at the borders of the endothelial cells (flanges) acted likewise, transporting vacuoles through the intercellular spaces. Micropinocytosis, was a distinctly different phenomenon, contributing, to a very small degree, to the intracellular enlargement of the vacuoles. It seems that this vacuolar mechanism of transportation serves an augmented metabolic need of the surrounding tissue.

Ultrastructural study of foetal and adult mouse renal tissue implanted in testis.

Kidneys of mice foetuses 15, 17, 19 days old, as well as kidneys of mice 1 and 4 weeks old of the pure C3H/SY species, were implanted into the right testis of 40 adult mice 1.5 to 2 months old, of the same species. The animals were sacrificed after 30 and 60 days and the evolution and development of the renal implants within the testis ware studied. The findings in the light as well as in the electron microscope, showed that the renal implants presented the histologic characters of nephroblastoma, which became clearer the more prolonged the time of the implantation was.

Morphogenesis and ultrastructure of the peripolar cells in the mouse kidney.

Peripolar cells are located in the outer layer of the Bowman's capsule. They surround the vascular pole of the renal corpuscle and project into the urinary space. Morphologically they are characterized by the presence of secretory granules within their cytoplasm. In order to study their embryological development, we used 60 C57bl mice embryos (15th to 19th gestational day), 10 newborn mice (2 hours to 6 days old), 10 preadult mice (8-30 days old) and 4 adults (4 months old). Some granular cells, dispersed at the outer and inner layer of the Bowman's capsule, appear on the 17th gestational day. Later, these cells are found around the vascular pole of the renal corpuscle, located exclusively at the outer layer of the Bowman's capsule. Their granules are spherical and variously dense, they are surrounded by a membrane and their number increases progressively with time and reaches a maximum on the 4th postnatal day. Following that, there is a diminution and then their population stabilizes. By the end of the first month, there are only a few such cells (mean number 1 to 2). They become smaller and they always project into the urinary space.

Ultrastructure of the rat hippocampus after isobaric respirative hyperoxia.

After exposing rats to an environment of isobaric hyperoxia, the ultrastructural alterations of the hippocampus were studied. No major alterations were found in the nerve cells. Of importance was the moderate osmiophilia and the spindle-like transformation of the mitochondria. Vacuolated synapses and neuraxons were found, containing amorphous material. Astrocytic perivascular end feet were found vacuolated in many places. Many endothelial cells of the capillaries presented high osmiophilia, which sometimes prevented structural details. Quantitatively, the findings were proportionally related to the time of exposure in the pure oxygen atmosphere (24, 48 and 65 hours).

Ultrastructural study of rabbit sciatic nerve regeneration following experimental excisional transection and autograft reconstruction.

This experimental study presents the ultrastructure of regenerating sciatic nerve of the rabbit, after transection and immediate end to end anastomosis, using perineural fascicular nerve autograft, in a sterile environment. Twenty-four hours, 1, 2, and 6 weeks after the anastomosis, the treated sciatic nerves were exposed and three segments were excised and studied. The first at the region of the graft and the others from the proximal and distal stump of the nerve, in the vicinity of the graft suture. The sections taken from the proximal part showed that the nerve structure was identical with the control. Degeneration and regeneration of nerve fibres were observed on the sections taken from the region of the grafts and from the distal parts. Macrophagic activity appeared mainly one week after the operation. Fibroblastic invasion started 24 hours after operation. A moderate amount of collagen fibres was gradually formed. The fibres were disposed in parallel with the neuraxon. Schwann cells were slightly affected initially but consequently they fully recovered and showed signs of extra-activity of the cytoplasm organelles, e.g., enlargement of the granular endoplasmic reticulum cisternae. The present study showed that the bridging of experimental gaps of rabbit's sciatic nerve, by means of autograft and by use of perineural suturing, was successful. The regenerating nerve fibres were growing through the graft towards the distal part of the nerve. In this process Schwann cells and fibroblastic activity play a key role, which is most favourably influenced by using the technique described in this paper.

[Presence of microcilia on the apical extremity of the cilia of the epithelium of the Fallopian tubes]. / Présence de microcils sur l'extrémité apicale des cils de l'épithélium de la trompe utérine.

The role played by the ciliated cells of the salpinx in the transport of the ovum has been the subject of numerous studies. In this work we examined the ultrastructure of the cilia of the ampullary portion of the oviductal epithelium in a series of mammals and in man. We found the classical structure of the motile cilia. The free part of the cilia, surrounded by the cell membrane, is composed by nine peripheral doublets and by a pair of central microtubules. In the species we examined, we had the occasion to observe an ultrastructural particularity of the cilia. It is about a group of microcilia placed on their apical extremity. These formations were observed in longitudinal sections and appeared aligned on the top of the cilium. They have a length of 200-300 A and a diameter of 100 A. Their number varies with the species examined. The proportion of cilia which presented microcilia is also different from species to species. The functional role of the microcilia is unknown.

Electron microscopic study of the oviduct epithelium of the rabbit: normal structure and modifications in 4 weeks experimental hydrosalpinx.

The ultrastructure of the oviduct epithelium in its ampullary portion has been examined in 10 rabbits. As normal control material we used microbiopsies of tubal mucosa, taken before ligature of the oviduct. The experimental material consisted of microbiopsies of tubal mucosa, taken in the same animals, 4 weeks after ligature of the oviduct and subsequent induction of hydrosalpinx. The main morphological alteration of the epithelium in hydrosalpinx consisted of absence of cilia in certain areas and presence of vacuoles in the cytoplasm of the ciliated cells. The secretory cells showed an increased number of granules in their cytoplasm. These observations suggest that 4 weeks after ligature of the oviduct the destruction of cilia and the increase of secretions may cause an impairment in the ovum transport through the oviduct.