PubMed Health⌕ Search

Biomedical subjects

F Harrisson

Publications and source records attributed to F Harrisson.

72 records · Page 4Linked to original sources
PubMed1981

Microspectrographic analysis of trypan blue-induced fluorescence in oocytes of the Japanese quail.

It was shown that the vital dye trypan blue injected subcutaneously is adsorbed on exogenous yolk and stored in oocytes of Japanese quails. The binding sites of the dye could be visualized by fluorescence microscopy. The spectral distribution of the trypan blue-induced fluorescence emitted by yolk granules was analyzed microspectrographically. The analysis revealed that yolk granules exhibit a deep red fluorescence radiation with a maximum intensity at 670 nm, when blue or green excitation light is used. This fluorescence was exclusively induce by the presence of trypan blue, and not by contaminants of the dye. The fluorescence intensity did not decrease during processing of the tissue throughout the different solvents routinely used in light microscopy, especially after fixation in Heidenhain's fluid, nor did it suffer from pronounced fading during irradiation of the tissue. Model experiments showed that the value of the fluorescence emission maximum was concentration-dependent, and that amounts as little as 5 x 10(-3) mg trypan blue per ml solution containing an excess of yolk as a substrate for the dye, could clearly be detected and measured. It is suggested that a highly diluted solution of trypan blue can be used without teratogenic effects, as a tracer for exogenous yolk uptake and migration into oocytes, and that fluorescence microscopy is a reliable method for its further localization. A detailed account of the procedure is reported.

Animals↗
PubMed1981

Resolution in light microscope autoradiography using a carbon-14 labelled line source.

Light microscope autoradiographs were prepared from a 14C line source Two factors that affect resolution were studied: emulsion thickness and section thickness. The distribution around the line source was determined using the half-distance (HD) value to quantify the resolution. An increase in HD value was observed with thicker sections or emulsion layers. The shape of the curve reflecting the grain density distributions around these line sources was very similar. After normalization in HD and relative grain density units, an average distribution was calculated and compared with the shape of normalized density distributions obtained from electron microscope autoradiographs. Other than a discrepancy near the source, an acceptable correlation was observed.

Autoradiography↗
PubMed1979

The effect of L-DOPA on the ultrastructure of the adenohypophysis of the Chinese quail, Excalfactoria chinensis.

Intraperitoneally injected L-DOPA was found to stimulate strongly the lysosomal system of all of the cell types of the adenohypophysis. We suggest that this amine may play a role in the regulation of the secretory activity of the gland by mediating the lysosomal activity, this role being of variable importance according to the fluctuations in hormonal activity. Utrastructural changes occur in some cell types following injection of L-DOPA. The question as to whether these changes are induced directly by L-DOPA or via the monoaminergic system of the hypothalamus and its hypophysiotropic hormones is discussed.

Animals↗
PubMed1978

Ultrastructural study of the adenohypophysis of the male Chinese quail.

The ultrastructural analysis of the adenohypophysis in the male Chinese quail reveals seven different types of granular cells, and agranular folliculo-stellate cells. The cell types are assumed to be endocrine cells and are classified as: Type I cells (presumptive LH-gonadotrophs), with dilated endoplasmic reticulum, perinuclear spaces, and granules of 150--260 nm; Type II cells (presumptive FSH-gonadotrophs), with regularly-shaped cytoplasmic cisterns and small granules (80--150 nm); Type III cells (presumptive thyrotrophs), very close in appearance to the type II cells of normal birds; Type IV cells (presumptive prolactin cells), with very large secretory granules (up to 400 nm), Type V cells (presumptive corticotrophs), with abundant and electron-dense granules (160--300 nm); Type VI cells, with irregularly-shaped granules; Type VII cells (presumptive somatotrophs), with abundant granules (130--220 nm) and less cytoplasmic structures. Cytological characteristics of the nucleus, and more particularly the presence of a Feulgen-postive nucleolus with a very particular ultrastructure are here reported. It is proposed that heterospecific associations of Chinese quail cells with chick cells can be used in embryological work for the study of cellular interactions.

Animals↗
PubMed1977

Electron microscope study of two types of cells in the anterior lobe of the Chinese quail adenohypophysis with special reference to their cytological features after photostimulation.

Two types of cells in the adenohypophysis of the Chinese quail, Excalfactoria chinensis, were studied by electron microscopy in birds receiving nine hours of light per day, and birds exposed to continuous light. Type-I cells of photostimulated quail have a well-developed vacuolar system consisting of cisternae and perinuclear spaces confluent with each other. The cytoplasm is restricted to small strands enclosing cell organelles. Secretory granules reaching 150-250 nm in size are scattered at the secretory pole of the cell. Exocytotic vesicles are not often observed. A circular Golgi apparatus with immature secretory granules in its neighbourhood is characteristic for this type of cell. Type-II cells of photostimulated quail present analogous features: distended endoplasmic reticulum and perinuclear spaces. A cup-shaped Golgi apparatus is often observed, with secretory granules, ranging in size from 80-150 nm. Exocytosis is regularly observed. Evidence is provided that the Type-I cell could be a LH-like cell (gamma-cell), and Type II, a FSH-like cell (beta-cell) in birds. The existence of relationships between gonadotrophs and thyrotrophs did, nevertheless, not exclude the possibility that one of the two types could be a thyrotroph.

Animals↗
PubMed1976

Histochemical characterization of the monoamine-containing cells of the adenohypophysis in the Chinese quail.

The demonstration of biogenic amine-containing cell is classically performed by means of the formaldehyde-induced fluorescence technique after administration of the monoamine precursors, L-dopa or 5-hydroxytryptophan (5-HTP. The injection of these two two compounds rapidly leads to the formation of large amounts. The biochemical pathway evoked above is studied in the avian adenohypophysis by two different methods involving enzyme...

5-Hydroxytryptophan↗
PubMedDate not supplied

Comparison between oogenesis and related ovarian structures in a reptile, Pseudemys scripta elegans (turtle) and in a bird Coturnix coturnix japonica (quail).

The aspect of the oogonia during their premitotic DNA synthesis and of the premeiocytes during their premeiotic DNA synthesis was studied in turtles by autoradiography, after injection of 3H-thymidine. As in the adult laying quail, the intrafollicular oocytes of the adult turtle go through three successive stages: prelampbrush, lampbrush and postlampbrush. During the prelampbrush and lampbrush stage two kinds of nucleoli exist: peripheral and central. In contrast to avian yolk, during its final rapid growth, no polyhedric protein yolk units were found in turtle yolk. As in the yellow yolk of quail, highly osmiophilic alcohol insoluble satellite yolk (egg oil) accumulates between the protein globular yolk of Pseudemys. Turtle yolk globules increase in volume by fusion. The penetration of peripherally assembled yolk in the turtle germinal disc is analogous to what we have described in the quail. Also in postlampbrush germinal discs subcortical ooplasmic organelles are present. Below the turtle germinal disc no structure comparable to the avian nucleus of Pander could be observed. No pyriform cells (as in squamate reptiles) and no pyriform-like cells (as in birds: Callebaut, 1991 b) were found in the chelonian ovarian granulosa layer. We could not demonstrate functional lacunoperitoneal communications via openings in the hilus ovarii of the turtle as is the case in birds.

Animals↗
PubMedDate not supplied

Spatial relationship between endophyll, primordial germ cells, sickle endoblast and upper layer in cultured avian blastoderms.

By isotopic quail-chicken chimera experiments of the Rauber's sickle or by radioactive labelling and isotopically replacing of the caudal endophyllic sheet in unincubated avian blastoderms, followed by culture, we demonstrated that the displacement of the endophyll by the cranially extending sickle endoblast is not exclusively a mechanical phenomenon, as suggested by earlier studies (Vakaet, 1962 a, b). Indeed, our study suggests that the sickle endoblast also migrates centripetally very soon (already after 5 h) in and through the caudal endophyll before ingression of upper layer cells takes place. We also describe the early spatial relationship between the three elementary tissues (endophyll, Rauber's sickle, upper layer) (Callebaut et al, 1996a) and the induction phenomena between quail sickle endoblast and chicken upper layer (UL) during the formation of the primitive groove. The latter already develops before ingression occurs. We found no evidence for an endophyllic origin of avian primordial germ cells.

Animals↗
PubMedDate not supplied

Only the endophyll-Rauber's sickle complex and not cells derived from the caudal marginal zone induce a primitive streak in the upper layer of avian blastoderms.

From unincubated quail blastoderms, we have excised, caudal marginal zones (caudally from Rauber's sickle), upper layer fragments covering Rauber's sickle or Rauber's sickle fragments alone (as controls), and placed them on the ventral side of the cranial quadrant of unincubated chicken blastoderms. Also, quail Rauber's sickle fragments, all or not associated with quail endophyll, were placed on the ventral side of isolated central upper layer discs of prestreak chicken blastoderms from which the deep layer was previously removed. Only the Rauber's sickle-derived cells (sickle endoblast cells), placed on unincubated or shortly incubated blastoderms induce, after culture, a primitive streak (PS) and a normal embryo. This indicates, together with previous experimental evidence, that even in the presence of endophyll, neither the deep part of the caudal marginal zone nor the upper layer above it can induce a primitive streak. This experimental study affords further evidence that the function of the avian Rauber's sickle is homologous to the function (mesoderm induction) of the vegetal dorsalizing cells (Nieuwkoop centre) in amphibian blastulas.

Animals↗
PubMedDate not supplied

Interaction of central subgerminal ooplasm with the elementary tissues (endophyll, Rauber's sickle and upper layer) of unincubated avian blastoderms in culture.

By placing a central subgerminal ooplasmic mass over isolated parts (alone or in association) of unincubated avian blastoderms and culture, we obtained an improvement in, or in some cases restoration of normal development. The evolution of small rectangular fragments (isolates) excised from different regions of the unincubated blastoderm was observed in association or not with subgerminal ooplasm. The only type of differentiation that was clearly distinguished in these isolates (taken from the caudocentral area centralis region) was a so-called 'primary neurula' formed by the endophyll and an associated thickened upper layer. In the present study, we also demonstrate that after removal of the area centralis from an unincubated caudal blastoderm quadrant, the upper layer (UL) and endophyll can no longer be restored from the associated subgerminal ooplasm (and form a miniature embryo), as is the case after removal of the endophyll alone. A deep layer (containing the endophyll) reformed during the migration of Rauber's sickle-derived cells into the neighbouring central subgerminal ooplasm only in the presence of the upper layer. This suggests that the upper layer has an early influence on the cells containing the original central deep ooplasm (delta ooplasm) to form the endophyll. The present study offers supplementary arguments in favour of the hypothesis that the endophyll is an inductor of preneurulation.

Animals↗
PubMedDate not supplied

Activation of avian embryo formation by unfertilized quail germ discs: comparison with early amphibian development.

In the present study we placed germ discs (or fragments containing the deep central part of it) from unfertilized laid or extracted quail eggs on the deep side of the upper layer of isolated anti-sickle regions from unincubated chicken blastoderms. After culture in vitro of associations where the central deep part of the germ discs was in contact with the deep side of the upper layer (UL), we observed in about 30% of the cases the onset of embryonic development. Both associated parts play a role in the final formation of an embryo. Our experimental results, suggest that the delta ooplasm of the nucleus of Pander influences the cranial upper layer to segregate an endophyll layer. The definitive embryonic structures i.e. mesoderm, epiblast and neural plate are derived from the chicken upper layer by respectively normal gastrulation and (pre)neurulation phenomena. Our experiments seem to have some homology with the association experiments of isolated cortices from various regions of unfertilized Xenopus eggs implanted into the ventroequatorial core of a recipient 8-cell Xenopus embryo.

Animals↗
PubMedDate not supplied

Timing of aortic valve replacement in elderly patients with symptomatic aortic valve disease using outpatient clinical parameters.

OBJECTIVE: To determine by how far worsening outpatient clinical parameters can affect outcome after aortic valve replacement, in patients with preserved left ventricular function and symptomatic aortic valve disease. PATIENTS AND METHODS: Five hundred patients with aortic valve disease underwent aortic valve replacement using a bioprosthesis. In 348 patients, another procedure was added. The preoperative outpatient parameters were investigated for their effect on hospital and long-term mortality. A Fisher exact, Kaplan-Meier univariate and Cox proportional hazard analysis were used. RESULTS: A retrospective follow-up of 2022 patient years was obtained. Five preoperative parameters were found to be more present in patients with a decreased left ventricular function: 1) severity of symptoms, 2) previous myocardial infarction, 3) conduction defects, 4) aortic valve regurgitation and 5) increasing need for medication. In patients with an ejection fraction of 50% or more, logistic regression analysis showed that hospital mortality increased with need for medication (p=0.004), previously performed CABG (0.015), increase in symptoms (p=0.018) and myocardial infarction (p=0.034). A Kaplan-Meier analysis revealed aortic valve regurgitation (p=0.017) and increased need for medication (p=0.012) as significant on long-term survival. Presence of a previous myocardial infarction showed a trend (p=0.062). A Cox' proportional hazard analysis showed for global mortality increased need for medication (p=0.010) and previous myocardial infarction (p=0.018) as independent factors and for long-term mortality, this was aortic valve regurgitation (p=0.001). CONCLUSIONS: Results after aortic valve replacement deteriorate with the presence of valve regurgitation, a preoperative myocardial infarction, increasing need for medication or severity of symptoms, even for an ejection fraction of 50% or more. Anamnesis with special care to the degree of symptoms and increasing need for medication early in the valve disease could lead to early referral, thereby reducing number of patients with severe symptoms and improving postoperative results.

Age Factors↗
PubMedDate not supplied

Gastric emptying rate for solid and for liquid test meals in patients with dyspeptic symptoms after partial gastrectomy and after vagotomy followed by partial gastrectomy.

BACKGROUND/AIMS: Gastric emptying rate for solid and for liquid test meals was investigated retrospectively in patients with longstanding epigastric distress after partial gastrectomy, either as primary treatment or after failure of vagotomy for peptic ulcer in order to find an explanation for the postoperative symptoms. METHODOLOGY: Radionuclide-labeled liquid and solid test meals were used to evaluate gastric emptying rate, at least one year after surgery. RESULTS: The lag phase for liquid test meals disappeared in all operated patients. Partial gastrectomy usually lead to fast emptying but this resective procedure, if performed after vagotomy, lead to stasis in a significant number of patients. Gastric emptying rate for solids increased in only a few of these symptomatic patients. In most of them however, there was a normal to decreased emptying rate. If a vagotomy had preceded the resective procedure, gastric emptying rate decreased significantly. CONCLUSIONS: In all these symptomatic patients, gastric emptying had been disturbed for at least one type of test meal. This makes investigation for both meals necessary, especially since there is a lack of correlation. Furthermore, if vagotomy fails to prevent ulcer recurrence, one should carefully consider all options before performing partial gastrectomy since gastric emptying rate after these consecutive procedures worsens considerably.

Adult↗
PubMedDate not supplied

The effect of stress on gastric emptying rate measured with a radionuclide tracer.

BACKGROUND/AIMS: Stress can delay gastric emptying rate. This phenomenon has not yet been investigated with a physiological solid test meal or a regional analysis. METHODOLOGY: We investigated the gastric emptying rate in beagle dogs using a radio-labeled solid test meal and a gamma camera. The transport to an unknown environment served as a stress stimulus. This offers the advantage to mimic fairly well the clinical situation just before a diagnostic or therapeutic procedure. Control values were obtained after the third investigation, in which all dogs were accustomed to the environment. RESULTS: Regional analysis of the emptying curves from the whole gastric region revealed that the length of the lag phase increased with stress, but the post-initial emptying rate remained unchanged. Emptying of the fundus changed hardly, but the antropyloral motor activity decreased during stress. CONCLUSIONS: Gastric emptying rate is impeded during stress. It is necessary to limit the unnatural stress-stimuli, in order to mimic the clinical situation. Measurement techniques that influence directly gastric emptying or act as a stress-stimulus by themselves are undesirable. A radionuclide solid test meal is preferable and a regional analysis reveals the impairment of the antral motility as the mechanism of the delay of gastric emptying.

Animals↗
PubMedDate not supplied

Smooth muscle cells in the peritubular tissue of the quail testis.

The aim of the present study was to reveal the presence of smooth muscle cells in the quail testis. We used an immunocytochemical and ultrastructural approach. The features of smooth muscle cells were present in the cells of the peritubular tissue and of the tunica albuginea. The peritubular cells formed a pseudo-stratified tissue. We suggest that the smooth muscle cells of the quail testis may be important in testicular contractile processes.

Actins↗