Biomedical subjects

F Harrisson

Publications and source records attributed to F Harrisson.

At least 19 recordsLinked to original sources

PubMed2004

Thromboembolic events after aortic valve replacement in elderly patients with a Carpentier-Edwards Perimount pericardial bioprosthesis.

OBJECTIVES: Thromboembolic events after aortic valve replacement with a bioprosthesis were the most frequently occurring complications in elderly patients. Whether this was valve related or dependent on other factors needed further exploration. METHODS: Five hundred patients with a median age of 73 years were followed retrospectively after aortic valve replacement with a pericardial prosthesis for occurrence of thromboembolism. Of these, 348 also underwent coronary artery bypass grafting. Twenty-five factors were investigated for their potential effect by using univariate and multivariate analysis. RESULTS: Univariate analysis revealed 6 significant factors: preoperative endocarditis (P =.0001), preoperative cerebrovascular accident (P =.002), use of postoperative warfarin sodium (Coumadin, DuPont Merck; P =.006), arterial hypertension (P =.023), size of valve prosthesis of 27 mm or larger (P =.023), and hospital thromboembolism (P =.040). There was a trend toward increased fatal thromboembolism in patients without medication. With a multivariate analysis, 4 factors remained significant: preoperative cerebrovascular accident (risk ratio, 4.8; P =.0016), warfarin sodium (risk ratio, 3.0; P =.0028), preoperative endocarditis (risk ratio, 5.6; P =.006), and hospital thromboembolism (risk ratio, 6.1; P =.016). Hypertension had a borderline effect. Age, sex, diabetes, 4 coronary artery factors, 3 other valvular factors, atrial fibrillation, and carotid artery disease had no significant effect. CONCLUSIONS: Some emboli seemed triggered by the valve prosthesis. A proper anticoagulant protocol but also a treatment of hypertension is important in the prevention of thromboembolism after aortic valve replacement with a bioprosthesis. We did not find a significant role of atrial fibrillation and carotid artery disease.

Aged↗

PubMed2003

Role of age, gender and association of CABG on long-term results after aortic valve replacement with a Carpentier-Edwards bioprosthesis in the elderly.

AIM: The problem of postoperative sudden death and the effect of age, gender and association of coronary artery bypass grafting were studied after implantation of a bioprosthetic valve in aortic position. METHODS DESIGN: retrospective investigation during 13 year. SETTING: general hospital. PATIENTS: 500 mostly symptomatic patients who received this bioprosthesis had a follow-up of 2,022 patient-year for 499 patients. INTERVENTION: aortic valve replacement with a Carpentier-Edwards pericardial prosthesis. MEASURES: hospital complications and mortality, long-term mortality with focus on sudden death and its risk factors, valve related complications and other cardiac events. RESULTS: Within the hospital: atrial fibrillation was the most frequent complication, for which only gender had an effect (p=0.014). The most occurring valve related complications were thrombo-embolic events. Mortality was adversely affected by male gender (p=0.040). Long-term results: thrombo-embolic events were the most important valve related complications. These events and haemorrhage, endocarditis and reoperation rate were not affected by the association of a CABG. Univariate analysis in patients over 73 showed that the need for CABG significantly increased global mortality (p=0.0001), occurrence of cardiac fatality (p=0.0003) and congestive heart failure (p=0.0036). Non-valve related factors seemed most responsible for postoperative sudden death. CONCLUSION: Age, male gender and the association of a CABG remain important determinants for postoperative survival, but not for the occurrence of valve related complications. Sudden death seems not always related to the valve prosthesis, but is as such classified by convention.

Age Distribution↗

PubMed2001

Effect of gravity on the interaction between the avian germ and neighbouring ooplasm in inverted egg yolk balls.

The developmental capacities of an avian germ (from before symmetrization to the moment of laying) are strongly diminished after inversion of its egg yolk ball followed by culture in egg white. Our present experiments show that even when the avian germ is completely horizontally inverted (without an upper or lower border) below its egg yolk ball before symmetrization, symmetrization and gastrulation phenomena take place. The germ grows slower and becomes smaller than after normal incubation. After culture of inverted unincubated germs, localized on freshly laid eggs, the closure of the neural tube is impaired and it remains open over a long distance. Although a primitive streak (PS) develops, mesoderm migration (mainly from the lateral part of the area pellucida) is also impaired. On sections through the germinal disc one can see the abnormal upward migration into the depth of the ooplasm and yolk of cells from the germ wall and the development of large cellular extensions encircling the yolk globules. Most prominent is the loss of contact between the superficial cell layers and the deep layer elements (junctional endoblast and yolk endoblast in the area opaca). Large areas without deep layer elements (even visible on surface micrographs) develop in the area vasculosa and area vitellina interna. The margin of overgrowth grows and extends normally over the egg yolk ball. An autoradiographic study after labelling of the yolk layers in inverted egg yolks reveals that mainly compression of the peripheral subgerminal and perigerminal ooplasm takes place. This suggests that the compression by the neighbouring yolk and upwards growth of cells are at the origin of the impaired development. After return to the normal upward orientation of the germ on the topmost part of the egg yolk ball, a more or less pronounced restoration to normal development takes place (depending on the duration of the inversion period and the age of the germ).

Animals↗

PubMed2001

Determinants of survival after aortic valve replacement as treatment for symptomatic aortic valve disease in the elderly.

BACKGROUND AND AIM OF THE STUDY: The effect of concurrent disease and cardiac comorbidity on survival after bioprosthetic valve replacement in elderly patients was assessed retrospectively. Risk factors were categorized as general, non-cardiac (age, diabetes, previously treated carcinoma) and cardiac (LVEF, three-vessel disease, previous CABG or valve replacement, and endocarditis). METHODS: A total of 400 elderly patients (median age 73 years; range: 71-76 years) was studied. Medical history included diabetes, previous CABG or aortic valve replacement (AVR), endocarditis and treatment of previous carcinoma. A left ventricular ejection fraction (LVEF) of <0.66 and presence of three-vessel disease were also investigated. Hospital deaths (and cause) were recorded; survival or date and cause of death after discharge were obtained by questionnaire. Kaplan-Meier univariate and Cox proportional hazards multivariate regression analyses were carried out. RESULTS: Mortality during follow up was 28.3%; hospital mortality was 3.8%. Univariate analysis showed five factors significantly to affect survival: LVEF, history of endocarditis, carcinoma, age and three-vessel disease. Fifteen of 38 patients with history of carcinoma died, 10 due to a malignancy. Of 76 patients with three-vessel disease, 26 died. A history of diabetes and previous CABG did not influence survival significantly. Four of eight patients with preoperative endocarditis died, all in hospital. Six of 11 patients died after redo-AVR, none before 36 months follow up. By Cox regression analysis, LVEF and histories of carcinoma and endocarditis remained significant. CONCLUSION: AVR should be performed before ventricular deterioration occurs. Previous CABG is not a contraindication for AVR. Endocarditis impaired survival. Long-term mortality after redo-AVR in this population was relatively high, but acceptable. AVR should also be performed in elderly patients with aortic valve disease. Since prognosis of symptomatic aortic valve disease is poor in the short term, AVR is indicated in patients treated for carcinoma.

Aged↗

PubMed2000

Avian junctional endoblast has strong embryo-inducing and -dominating potencies.

In the present study, we demonstrate that quail junctional endoblast fragments have powerful embryo-inducing potencies when placed on the deep side of the upper layer (UL) of the anti-sickle region of unincubated chicken blastoderms. Moreover, in most cases the inducing potencies of the autochthonous Rauber's sickle-endophyll complex were inhibited at distance. Also, junctional endoblast still in situ in an early streak embryo strongly inhibits the inducing capacities of a Rauber's sickle - endophyll complex apposed on the deep side of the upper layer of the cranial part of the area pellucida. So junctional endoblast, besides embryo inducing potencies also seems to dominate and to inhibit at distance the gastrulation potencies of an ectopically placed or autochthonous Rauber's sickle - endophyll complex.

Animals↗

PubMed2000

Localisation of epidermal growth factor receptor in the quail ovary.

The present study focuses on the distribution of EGFR in the follicular and stromal compartments of the Japanese quail (Coturnix coturnix japonica) ovary, using immunohistochemical methods and a histological ligand binding assay. EGFR was predominantly present in granulosa cells during each stage of the folliculogenesis. Furthermore, EGFR was also detected in thecal cells and in oocytes. In some cells of the vascular endothelium, of the ovarian smooth muscle, and of the surface epithelium, the presence of EGFR was detected as well. The presence of EGFR allows to formulate the hypothesis that EGFR-ligands are involved in the autocrine and/or paracrine regulation of oocyte maturation and of folliculogenesis in the quail, and possibly in all birds.

Animals↗

PubMed2000

Gastric emptying rate measurement after vertical banded gastroplasty.

BACKGROUND: In vertical banded gastroplasty (VBG), a small proximal gastric pouch is created, which is believed to fill rapidly and to empty slowly. METHODS: In 13 patients who underwent VBG, gastric emptying rate was measured. A radiolabelled solid test meal was used before and 2 weeks after operation. From a region of interest above the whole stomach, the proximal pouch and the distal stomach, half emptying time as well as retention percentage were derived. RESULTS: All patients experienced early satiety and gastric fullness after ingestion of a small test meal. The proximal pouch emptied rapidly. The evacuation of the test meal from the whole gastric region as well as the distal stomach were not altered significantly by the operation. CONCLUSION: VBG is a safe operation which reduced weight significantly. Early satiety, however, induced by this technique, cannot be explained alone by slow emptying of the proximal pouch. The nature of the outlet of the pouch as well as the behavior of its wall must be considered.

Adult↗

PubMed2000

Comparison of anterior and geometric mean liquid and solid gastric emptying rates in dogs and in patients after partial gastrectomy.

OBJECTIVE: The purpose of this study was to determine if geometrical correction is necessary in the study of gastric emptying rate (GER) for liquids, using a low-energy radionuclide, such as 99mTc. Solid test meals were considered the reference. METHODS: Both solid and liquid GERs were investigated using regional analysis. Anterior data were compared with geometrically corrected values in 15 dogs and 9 partial gastrectomy patients. RESULTS: Anterior and geometrically corrected measurements differed significantly for solid food in the whole gastric region and in the antrum. Geometrically corrected values differed slightly from anterior data after partial gastrectomy. No difference was found for liquid food. Liquids redistributed much faster than solids within the stomach. CONCLUSION: Measurement of GER using a single-phase liquid meal does not require geometrical correction. This is due to the rapid intragastric redistribution of the liquid. Geometrical correction for solid food can be omitted only after partial gastrectomy.

Adult↗

PubMed1999

Distribution of apoptosis-related proteins in the quail ovary during folliculogenesis: BCL-2, BAX and CPP32.

It is suggested that follicular apoptosis is driven by the status of the BCL-2: BAX rheostat, and that CPP32 is a key effector of granulosa cell death. In the present study, we have immunohistochemically localized two BCL-2 family members, BCL-2 and BAX, and one caspase, CPP32, in the quail ovary during folliculogenesis. BCL-2 was predominantly found in the granulosa cells of developing follicles. BAX was detected in some follicular cells of atretic follicles, and in the nucleus of some prelampbrush oocytes. Expression of CPP32 was detected in leukocytes and in follicular cells of atretic follicles. Immunostaining was also found in interstitial cells, in surface epithelial and vascular endothelial cells, and in some thecal cells of post-ovulatory follicles. In the granulosa cells of non-growing and small prehierarchal follicles, a weak immunostaining was observed. We can conclude that in the avian ovary, BAX and CPP32 are involved in atresia. The present results support the BCL-2: BAX rheostat hypothesis.

Animals↗

PubMed1999

Localization of nitric oxide-related substances in the quail ovary during folliculogenesis.

In the present study, nitric oxide (NO)-related substances, namely NO synthase (NOS), L-citrulline, cGMP and nitrotyrosine, have been localized in the quail ovary, using NADPH-diaphorase staining and immunohistochemical methods. The results indicate the presence of the NOS isoforms, showing distinct cell-specific distribution patterns in the quail ovary. Inducible NOS is primarily present in leukocytes, endothelial NOS in granulosa cells, and neuronal NOS in nerve cells, oocytes, interstitial cells and granulosa cells of pre-hierarchal follicles and of the germinal disc region of pre-ovulatory follicles. NOS activity, indicated by the presence of L-citrulline, is observed in oocytes, nerve cells, interstitial cells and a few granulosa cells of pre-hierarchal follicles. Detection of accumulated cGMP indicates that granulosa cells of pre-hierarchal and of pre- and post-ovulatory follicles, the theca interna of pre-ovulatory follicles, and oocytes are main targets of NO. Nitrotyrosine, a marker of peroxynitrite activity, is mainly localized in atretic follicles and in post-ovulatory follicles. It is concluded that the quail ovary possesses a NO/NOS system, and that NO may be considered as a mediator involved in various ovarian processes, including atresia.

Animals↗

PubMed1999

Endophyll orients and organizes the early head region of the avian embryo.

By placing endophyll on the caudal area marginalis situated behind Rauber's sickle of avian unincubated blastoderms, we observed after using the quail-chick chimera system and culture the development of a (pre)neural plate or a miniature embryo, head-oriented towards this endophyll. A Rauber's sickle fragment placed in the same conditions gives no reaction. If we place endophyll close to Hensen's node (stage 4 Vakaet, 1962) on an isolated anti-sickle region of an avian unincubated blastoderm in vitro, a similar endophyll-oriented development takes place after culture. Under the same conditions, but in the absence of endophyll, a Hensen's node provokes a thickening of the upper layer in the immediate neighbourhood, eventually with formation of a neural axis, oriented according to the original caudocranial direction of the graft. Our study indicates that avian endophyll (from unincubated blastoderms) can induce in the upper layer a (pre)neural plate, with or without neural folds. By interaction with sickle endoblast coming from Rauber's sickle (the early gastrulation organizer: Callebaut and Van Nueten, 1994), or from Hensen's node (a later avian organizer: Waddington, 1932), it can orient or re-orient the head region and the caudocranial direction of an induced miniature embryo. The conclusions from our embryological experiments are in agreement with the results obtained by recent molecular biology studies.

Animals↗

PubMed1998

Histochemical demonstration of apoptotic cells in the chicken embryo using annexin V.

This study describes the use of biotinylated annexin V for the histochemical detection of apoptotic cells in cultured chicken embryos during gastrulation. This method is based on the Ca2+-dependent binding of annexin V to phosphatidylserine, a negatively charged phospholipid, located at the inner leaflet of the cell membrane in living cells. However, in the early stages of apoptosis, phosphatidylserine is translocated to the outer layer of the cell membrane and can then be recognized by annexin V. Applying this method in cultured chicken embryos during gastrulation, we obtained labelling of apoptotic cells in the three germ layers. In the epiblast and mesoblast, labelling was predominantly present in the region lateral to the primitive streak. At the level of the germinal crescent, labelled cells were also found in the epiblast. Labelled cells in the deep layer, which is a heterogeneous tissue layer composed of endophyll, sickle endoblast and definitive endoblast, were rather scarce. The distribution of cells, as observed in this study after labelling with annexin V in light microscopy and confocal laser scanning microscopy, is consistent with distributions reported by other authors using other approaches and with our previous observations made with the TUNEL technique and by electron microscopy after fixation in a tannic acid-based fixative. The main advantages of this method over other more sophisticated methods is its easiness and rapidity of execution and the fact that both early and late stages of apoptosis are detected.

Animals↗

PubMed1998

Induction of (pre) gastrulation and/or (pre) neurulation by subgerminal ooplasm and Rauber's sickle in cultured anti-sickle regions of avian unincubated blastoderms.

Rauber's sickle fragments from unincubated quail blastoderms, associated or not with chicken central subgerminal ooplasm, were placed on the deep side of the upper layer (UL) of the isolated anti-sickle region of unincubated chicken blastoderms and cultured in vitro. When only a Rauber's sickle fragment was placed, we observed always a pronounced thickening of the UL (pregastrulation) in the immediate neighbourhood. Some times a primitive streak (PS) developed. When the Rauber's sickle fragment was "sandwiched" between the UL and a central subgerminal ooplasmic mass [containing the nucleus of Pander (1817)], always a (pre)neural plate accompanied by endophyll developed, not or well associated with a primitive streak. In the latter case a complete miniature embryo developed. De novo formation of endophyll was observed. As it contained quail nuclei it was derived from Rauber's sickle cells which colonized the subgerminal ooplasm. Our experiments indicate that the uncommitted upper layer (UL) of the anti-sickle of unincubated blastoderms constitutes an excellent reactor tissue for inductions. The thickening induced in the UL of the anti-sickle region by Rauber's sickle initiates (pre)gastrulation and the thickening induced by endophyll initiates (pre)neurulation. In the beginning, pregastrulation and preneurulation seem to be independent phenomena. It is only later, when both become correctly linked at the right place and time, that a normal embryo will develop.

Animals↗

PubMed1997

Avian gastrulation and neurulation are not impaired by the removal of the marginal zone at the unincubated blastoderm stage.

In the present study, we removed the whole area marginalis, Rauber's sickle and the peripheral part of the area centralis from unincubated chicken blastoderms (st IV, Vakaet, 1962a). By placing a fragment of a quail Rauber's sickle (functioning as early gastrulation organizer: Callebaut and Van Nueten, 1994) at different places and oriented in different directions on the remaining central part of the area centralis, we observed, after in vitro culture, a normal embryonic development. This indicates that the area marginalis itself is not indispensable for gastrulation and neurulation. Our study also indicates that none of the three elementary tissues (Rauber's sickle, endophyll and upper layer) of the avian unincubated blastoderm present an irreversible functional polarity.

Animals↗

PubMed1997

Presence and function of growth factors in the avian ovary.

It is now evident that a number of growth factors and cytokines are intimately involved in ovarian processes. This review focuses on these autocrine/paracrine modulators in terms of describing their presence and function in avian ovaries.

Animals↗

PubMed1996

Immunohistochemical localization of transforming growth factor-beta 1 beta 2 during folliculogenesis in the quail ovary.

Immunohistochemical methods were used to show the presence and distribution of transforming growth factor-beta 1 and beta 2 during folliculogenesis in quail ovarian tissues. The results indicated that both transforming growth factor-beta subtypes are present. Immunolabelling for transforming growth factor-beta 1 demonstrated that prelampbrush oocytes are immunoreactive in the Balbiani complex, and developing and pre-ovulatory oocytes in the zona radiata. Immunolabelling was also associated with granulosa cells. The number of stained granulosa cells decreased during folliculogenesis. In the pre-ovulatory follicles, immunolabelling was found predominantly in the theca interna. Immunolabelling for transforming growth factor-beta 2 was associated with the zona radiata of developing and pre-ovulatory follicles, and with stromal interstitial cells. Moderate immunoreactivity was found in the Balbiani complex of prelampbrush oocytes. Weak immunolabelling was localized in the granulosa cells of prelampbrush follicles, and in a few cells of the theca interna of pre-ovulatory follicles. The immunolocalization of transforming growth factor-beta 1 and -beta 2 in the quail ovary supports their autocrine and/or paracrine role in avian ovarian processes.

Animals↗

PubMed1996

Map of the Anlage fields in the avian unincubated blastoderm.

By excision at different sites of rectangular fragments from unincubated chicken blastoderms and replacement by isotopic fragments from unincubated quail blastoderms, we could make the first complete map of the Anlage fields in the freshly laid avian blastoderm. All the Anlage fields (Fig. 11) are found in the upper layer (UL) of the caudal half of the area centralis (bordered by the Rauber-Koller's sickle). In the UL of the area marginalis, peripheral to Rauber-Koller's sickle, neither gastrulation nor neurulation phenomena could be observed. Similar heterotopic replacement experiments indicate that before incubation, the different parts of the UL of the area centralis are still uncommitted or reversibly committed. The Anlage fields of chordamesoblast and definitive endoderm (gut endoderm) in unincubated avian blastoderms appeared to be disposed caudally in the caudal half of the area centralis. As far as we know we are the first to demonstrate that the Anlage field of the definitive gut endoderm (which is derived from the upper layer: Hunt, 1937; Vakaet, 1962b) is localized in the most caudal upper layer part of the area centralis just centrally to the Rauber-Koller's sickle. The Anlage field of the neural plate is localized in the upper layer over the more cranial endophyll. The Anlage of the brain is shield-shaped, whilst the other Anlage fields are sickle-shaped, parallel with the Rauber-Koller's sickle. Their general hemicircular disposition and form still seem to reflect (together with the Rauber-Koller's sickle) the original ooplasmic radial symmetry (Callebaut, 1972) combined with the eccentricity of the deep layer components, which was observed during early symmetrization by gravitational orientation of the egg yolk (Callebaut, 1993a,b). The Rauber-Koller's sickle might be homologous with the vegetal dorsalizing cells or centre of Nieuwkoop (1973) in amphibian blastulas.

Animals↗

PubMed1996

Localization of apoptotic cells by direct immunogold detection of digoxigenin-labeled genomic DNA in semithin sections.

In this study, which correlates apoptosis with avian ovarian physiology, we modified an in situ DNA nick end-labeling method using immunogold reagents to detect apoptotic cells in semithin sections of quail ovaries embedded in glycol methacrylate resin. Special attention was paid to the prevention of background staining. The results are comparable with those of the ApopTag peroxidase kit in paraffin-embedded ovaries.

Animals↗