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Biomedical subjects

N Girard

Publications and source records attributed to N Girard.

At least 73 records · Page 4Linked to original sources
PubMed1997

Ischemic cerebrovascular disease in children: retrospective study of 35 patients.

A 10-year review of a neuropediatric department experience with childhood ischemic cerebrovascular disease identified 35 patients with arterial ischemic stroke. The ability to diagnose stroke in children has improved with the development of imaging techniques in the past few years. Children have a wide array of risk factors for ischemic strokes, since some are acquired and others are congenital. Twenty-eight associated conditions (80%) were found in our patients and we identified 17 specific causes (48.5%) among them. The cause of stroke in children is important to recognize because stroke is likely to recur depending on the etiology.

Adolescent↗
PubMed1997

Clues for care.

Explore the source record for details and available documents.

Adult↗
PubMed1997

Preoperative assessment.

Surgery is moving into the community with the advent of same day surgery, noninvasive surgery, and early admit and short-stay surgeries. Preoperative assessment and planning for postoperative recovery is now being eliminated or drastically decreased in the hospital because those nurses no longer have enough contact with the patients. As a result, clinics, physician's offices, and other community-based centers must assume these activities to ensure quality patient care that is coordinated and efficient. This article gives a review of the most common preoperative assessment needs, with implications for the surgical experience that the nurse practitioner may now have to complete.

Aged↗
PubMed1996

CD44 and hyaluronan binding by human myeloid cells.

The CD44 cell surface molecule has been shown to be the principal cell surface receptor for hyaluronan (or hyaluronic acid), a glycosaminoglycan component of marrow extracellular matrix. However, its affinity for hyaluronan is not constitutive, since it depends on the cell type, the stage of differentiation and on activation by external stimuli including certain anti-CD44 antibodies and phorbol esters. Except for a few lymphoid cell lines, hematopoietic cells do not spontaneously bind hyaluronan and initial studies reported that, contrary to lymphocytes, myeloid cells could not be activated to bind hyaluronan. Because CD44 plays an important role in the initial phases of hematopoiesis, as shown by experiments using blocking anti-CD44 monoclonal antibodies, its capacity to mediate adhesion of primitive myeloid cells has been investigated. It was found that CD44 could mediate spontaneous adhesion to hyaluronan of immature myeloid cell lines KG1, KG1a, and TF1, which serve as a model for hematopoietic progenitors. However, despite expressing high amounts of CD44, no more than 15% of bone marrow progenitors could adhere to hyaluronan. Recent experiments have shown that a very important feature of CD44 is its capacity to be rapidly activated by certain antibodies and cytokines (GM-CSF and KL) from a low affinity to a high affinity state for hyaluronan. These data shed light on striking similarities in the functional regulation of CD44 and of the two integrin receptors VLA-4 (a4b1), and VLA-5 (a5b1), which are also expressed on hematopoietic progenitors. The relevance of these data to the regulation of normal hematopoiesis and mobilization of CD34+ progenitors in the view of cell grafting is analyzed. In addition, we show that in idiopathic myelofibrosis, the amount of hyaluronan is markedly increased in the extracellular matrix from the myeloproliferative spleen. Considering that the production of cytokines is enhanced in this disease, we discuss whether CD44-hyaluronan interaction may have a role in the pathophysiology of this myeloproliferative syndrome.

Antibodies, Monoclonal↗
PubMed1995

Enzyme-linked hyaluronectin: a unique reagent for hyaluronan assay and tissue location and for hyaluronidase activity detection.

Several techniques for assaying and localizing hyaluronan (HA), all based on the affinity to hyaluronan of proteins isolated from cartilage, chondrosarcoma, or brain, have been proposed. We show here that a unique reagent, alkaline phosphatase-linked hyaluronectin, can be used to assay hyaluronan in biological fluids or tissue extracts (enzyme-linked sorbent assay method) and to characterize it in cells or tissue sections in two steps: reagent incubation and staining. Results of assays in biological fluids or tissue extracts showed a good correlation with results of the previously described technique using antibodies to detect hyaluronectin bound to a plastic microtest plate (B. Delpech et al., 1985, Anal. Biochem. 149, 555-565) for both low concentrations (< 1 mg/liter, r = 0.973, P < 0.001) and high concentrations (> 1 mg/liter, r = 0.953, P < 0.001). The interassay variations were 8.5% when the assay was performed at 4 degrees C and 18.5% at 37 degrees C. The intraassay variations under those conditions were, respectively, 14.4 and 6.5%. Tissue HA could be detected easily with the reagent, as shown in fetal tissues and in tumors. Specificity of the reaction was controlled either by blocking the reagent with an excess of hyaluronan (which was not possible with other glycosaminoglycans) or by destroying tissue hyaluronan with streptomyces hyaluronidase. Alkaline phosphatase-linked hyaluronectin was also used to assay hyaluronidase activity in several biological fluids. One-hour incubation of hyaluronidase preparations on HA-coated plates made it possible to detect as low as 1 mU bovine testis hyaluronidase and 0.1 mTRU streptomyces hyaluronidase. Four-hour incubation made it possible to detect activity in a 1/12,500 dilution of human serum.

Alkaline Phosphatase↗
PubMed1995

[Current imaging of vasculo-neural conflicts in the cerebellopontine angle].

UNLABELLED: To demonstrate the high sensitivity of high definition MRI and particularly "Constructive Interference in Steay State" (Ciss) imaging sequence, in depicting neurovascular conflicts in the CP angle cistern, cisternographic imaging and high definition T1 weighed (Turbo flash), contrast enhanced imaging were used to investigate hemifacial spasm (72 patients) and tinnitus with abnormal BER (5 patients). The study was complemented with Angio MR in 25 patients. The results were compared with findings in a control group of 200 patients, and with the surgical observations in 57 operated cases. In hemifacial spasm, the morphology of the neurovascular conflict was determined, as well as the site of compression (lateral medullary fossa 38 cases; nerve 9; both 15 cases), and the vessel involved (VA 25 cases; PICA 16 cases; AICA 10 cases; VA and PICA 8 cases; VA and AICA 3 cases; lateral medullary vein 1 case). In tinnitus (5 cases), the AICA was involved in every case in the IAM. Among 57 operated cases, only one false negative was observed. In the asymptomatic control group, a nerovascular conflict was observed in 3, 5% of the cases only. CONCLUSION: CISS imaging is the single most efficient technique, but the combined used of the 3 types of imaging brings the highest diagnostic efficiency, for identifying a neurovascular conflict in the CPA cistern.

Adult↗
PubMed1995

In vivo MR study of brain maturation in normal fetuses.

PURPOSE: To illustrate normal maturation of the fetal brain, including the migrational layer, gray matter, early myelination of internal capsules, optic radiations, and corona radiata. METHODS: Seventy-seven fetal brains, ranging from 21 to 38 weeks of gestational age, were examined with MR in vivo; 33 were considered normal. MR examinations were performed as T1-weighted sequences in the axial, sagittal, and coronal planes. The neuropathologic examination (four cases) and clinical and/or neuroradiologic examinations confirmed the antenatal data. RESULTS: From 21 to 25 weeks, the cerebral ventricles are large, corresponding to the relative fetal hydrocephalus. A slight high signal intensity can be observed in the basal ganglia as early as 21 weeks. In the cerebral hemispheres, a multilayered pattern that can be observed from 23 to 28 weeks includes the cortical ribbon, the germinal matrix, and an intermediate layer corresponding to the migrating glial cells. These findings are probably related to areas of increased cellularity. A high signal intensity can be seen within the dorsal part of the brain stem as early as 23 weeks, within the posterior limb of the internal capsules at 31 weeks, and within the central area of the cerebral hemispheres at 35 weeks. Those patterns are probably caused by the evolving process of myelination. CONCLUSIONS: MR allows depiction of signal changes corresponding either to an increase in cellularity or to the evolving processes of myelination, depending on the stage of the pregnancy.

Brain↗
PubMed1994

Expression of opioid peptides in cells and stroma of human breast cancer and adenofibromas.

The expression of beta-endorphin, Met-enkephalin and Leu-enkephalin was studied in 63 malignant and benign human breast tumors using immunohistochemical methods. Among invasive ductal carcinomas, 93% were positive for beta-endorphin, 87% for Leu-enkephalin and 90% for Met-enkephalin, in both the tumor stroma and the cell bodies. Enkephalin was predominant in cells, whereas endorphin was predominant in stroma. Nearly the same distribution was found in adenofibromas. In pericancerous normal tissue, neuropeptides were predominantly expressed in the stroma. Although the neuropeptide expression is not cancer-specific, it could be cancer-related, since the results suggest that the neuropeptide expression could reflect the host response to cancer cells and not only the cancer cell activity. The possibility of a direct action of the nervous system on stroma reaction and then on cancer cells is discussed.

Adenofibroma↗
PubMed1994

Reversible tonsillar prolapse in vein of Galen aneurysmal malformations: report of eight cases and pathophysiological hypothesis.

We report eight cases of vein of Galen aneurysmal malformation (VGAM) associated with a "Chiari type I malformation." In four cases magnetic resonance imaging (MRI) or computed tomography performed in the neonatal period did not demonstrate the posterior fossa anomaly, which appeared on later scans. In the other cases the MRI was performed in infancy and the anomaly was already present. We compared the venous phases of the posterior fossa angiograms and the MRI in these patients. In all eight cases, the angiograms showed a reflux in the cerebellar veins, via the petrous vein, associated with a uni- or bilateral stenosis or thrombosis of the distal posterior dural sinuses. Furthermore, in two cases the posterior fossa returned to normal on MRI following endovascular treatment, while in three cases the herniation of the cerebellar tonsils decreased after the embolization. Tonsillar prolapse becomes irreversible when the venous outlet is incapable of taking the flow even when the VGAM has been treated adequately. In eight additional cases of VGAM for which MRI and angiogram studies were available and in which stenosis or thrombosis of posterior dural sinuses was present without tonsillar prolapse, no reflux into the cerebellar veins was shown. We suggest that the posterior fossa hydrovenous congestion is a result of inadequate venous drainage and that the tonsillar descent is reversible if adequate venous drainage is reconstituted following therapeutic embolization of the fistula. Tonsillar prolapse is not a consequence of mass or raised intraventricular pressure. Our observation suggests that in some other conditions, the "Chiari I malformations" may be secondary to early hydrovenous dysfunction of the posterior fossa.

Arteriovenous Shunt, Surgical↗
PubMed1994

3D-FT MRI of the facial nerve.

Contrast-enhanced 3D-FT MRI of the intrapetrous facial nerve was obtained in 38 patients with facial nerve disease, using a 1.0 T magnet and fast gradient-echo acquisition sequences. Contiguous millimetric sections were obtained, which could be reformatted in any desired plane. Acutely ill patients, were examined within the first 2 months, included: 24 with Bell's palsy and 6 with other acute disorders (Herpes zoster, trauma, neuroma, meningeal metastasis, middle ear granuloma). Six patients investigated more than a year after the onset of symptoms included 3 with congenital cholesteatoma, 2 with neuromas and one with a chronic Bell's palsy. The lesion was found incidentally in two cases (a suspected neurofibroma and a presumed drop metastasis from an astrocytoma). Patients with tumours had nodular, focally-enhancing lesions, except for the leptomeningeal metastasis in which the enhancement was linear. Linear, diffuse contrast enhancement of the facial nerve was found in trauma, and in the patient with a middle ear granuloma. Of the 24 patients with an acute Bell's palsy 15 exhibited linear contrast enhancement of the facial nerve. Three of these were lost to follow-up, but correlation of clinical outcome and contrast enhancement showed that only 4 of the 11 patients who made a complete recovery and all 10 patients with incomplete recovery demonstrated enhancement. Possible explanations for these findings are suggested by pathological data from the literature. 3D-FT imaging of the facial nerve thus yields direct information about the of the nerve condition and defines the morphological abnormalities. It can also demonstrate contrast enhancement which seems to have some prognostic value in acute idiopathic Bell's palsy.

Adolescent↗
PubMed1994

3D-FT thin sections MRI of prolactin-secreting pituitary microadenomas.

We studied 76 patients with endocrinological features of prolactin-secreting microadenoma by MRI, using three dimensional (3D) gradient echo acquisition (FLASH) sequences. MRI revealed a focal signal abnormality in the pituitary in all 37 patients who had not previously taken bromocriptine. However, focal abnormality was shown in only half the patients had been on dopamine agonist therapy; the MRI findings in these 39 patients were not affected by the duration and dosage bromocriptine, nor by the time elapsed since its discontinuation. The microadenoma gave spontaneous high signal on the unenhanced T1-weighted images in 8 cases; it was not seen on unenhanced images in 25 cases. It appeared as low signal within the enhancing gland in 51 cases but enhanced in 7 cases. The 3D technique gives thin (1 mm) slices and therefore facilitates detection of small focal abnormalities in the pituitary gland (2 x 2 mm). In the 19 previously treated patients in whom MRI did not demonstrate a focal abnormality, it showed localised atrophy of the gland in 3, a large, round gland with homogeneous signal in 1, and a heterogeneous appearance in 11; it was normal in 4 cases.

Adolescent↗
PubMed1994

Dilation of woven and knitted aortic prosthetic grafts: CT scan evaluation.

Because there are few reports in the literature concerning short- and medium-term outcome of woven and knitted aortic prosthetic grafts, we conducted CT evaluations in 58 asymptomatic patients (53 males and five females with a mean age of 63.5 years) undergoing infrarenal aortic reconstruction between June 1988 and June 1991. Joined CT slices after contrast enhancement, centered on the proximal anastomoses, prosthetic bodies, and prosthetic limbs, were obtained in the early (mean 19 days) and late (mean 19 months, range 6 to 40 months) postoperative periods. In end-to-side aortoprosthetic anastomoses (n = 28), early and late CT examinations revealed that the anteroposterior diameter increased 1.9% (p = NS) and 8.8% (p < 0.0001) for woven and knitted grafts, respectively. In end-to-end aortoprosthetic anastomoses, the diameter of the prosthetic body on early CT scans increased 12.6% (p < 0.0001) and 28% (p < 0.0001) for woven and knitted prosthetic grafts, respectively, as compared with diameter values provided by the manufacturer. Dilation continued to progress 2.2% (p < 0.04) for woven and 6.2% (p < 0.0002) for knitted prosthetic grafts on late CT scans. The mean diameter of the prosthetic graft limbs (n = 96) increased 22.3% (p < 0.0001) and 34.6% (p < 0.0001) for woven and knitted prosthetic grafts, respectively, on early CT scans as compared with manufacturers' values. Secondary increases were 3.2% (p < 0.002) and 7.7% (p < 0.007) for woven and knitted prosthetic grafts, respectively. These data show that dilation of aortic prostheses occurs early in most cases, most likely soon after declamping of the graft, as shown by recent intraoperative measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Localization and solubilization of hyaluronan and of the hyaluronan-binding protein hyaluronectin in human normal and arteriosclerotic arterial walls.

Hyaluronectin (HN), a hyaluronan (hyaluronic acid, HA)-binding glycoprotein isolated from human brain, was studied in normal and atherosclerotic human arteries. It can be detected and assayed in tissue samples by immunohistochemistry. In addition, its high and specific affinity for HA makes it possible to develop specific histological localization of HA using HN as a probe. We tested the presence of HN and HA in human carotid artery samples from adults and newborns. In atheroma-free arterial samples HN was found in the intima, between smooth muscle cells and in the adventitial extracellular matrix. In atherosclerotic lesions, HN was strongly expressed in the diffuse thickened intima and surrounding extracellular microcrystalline calcium deposits, and very little in the lipid core. HA was found in the same locations. The similar localizations of HN and HA shown by immunohistology and demonstration of HN-HA complexes by high pressure liquid chromatography (HPLC) suggest that they are associated in vivo.

Adult↗
PubMed1994

Breast reconstruction using an innovative flap procedure.

Most patients consider breast reconstruction an essential part of total breast cancer management. In the wake of the silicone-gel implant controversy, more women are considering breast reconstruction using their own tissue. Since 1982, the transverse rectus abdominis myocutaneous (TRAM) flap has become a well-established and popular method of reconstruction. For many women, TRAM flap reconstruction is the surgery of choice following mastectomy. It offers victims of breast cancer the potential for soft, natural-appearing breast mounds without the risks associated with other types of flaps or manufactured implants. A description of autogenous tissue grafting using the TRAM flap for breast reconstruction is provided with associated perioperative nursing care guidelines and potential complications.

Adult↗
PubMed1994

The case management model of patient care delivery.

Case management is a model of care delivery that integrates patient and provider satisfaction and consideration of cost factors and provides a method of managing individuals' holistic health concerns. Using the case management approach, nurses can optimize client self-care, decrease fragmentation of care, provide quality care across a continuum, enhance clients' quality of life, decrease length of hospitalization, increase client and staff satisfaction, and promote cost-effective use of scarce resources. Case management offers nurses an opportunity to demonstrate their roles in multidisciplinary health care teams. Case management is relevant in ambulatory surgery settings and in the perioperative care of complex surgical patients.

Humans↗
PubMed1994

Expression and effects of hyaluronan and of the hyaluronan-binding protein hyaluronectin in newborn rat brain glial cell cultures.

Hyaluronan (HA) is a polymerized nonsulfated extracellular matrix glycosaminoglycan that may be involved in brain development. We have tested the expression of HA and the HA-binding protein hyaluronectin (HN) in glial cell cultures from newborn rat brain. HA was secreted into the culture medium by type 1 astrocytes in the first stages of the primary cultures. The secretion was high during cell proliferation, reached a maximum when they were confluent, and then decreased. HA was not secreted at a detectable level by total O-2A lineage cell-enriched cultures. HA labeled small O-2A progenitor cells (GFA-, A2B5+, HA+), small O-2A progenitorlike (GFA-, A2B5-, HA+) cells, and type 2 astrocytes (GFA+, A2B5+, HA+), but not mature oligodendrocytes (Galc+, HA-). In contrast to HA, hyaluronectin labeled oligodendrocyte membranes (i.e., more mature cells) from day 8. A2B5+ GFA- cells were found to be either HA+ or HN+ at days 7-9, suggesting intermediary stages. The addition of HA to primary cultures and to O-2A progenitor-enriched cultures decreased significantly the increase in the number of O-2A progenitors, of mature (Galc+) oligodendrocytes proportionally to the decrease of the O-2A progenitor number, and of BrdU+ cells, suggesting that HA acts (directly or indirectly) on O-2A cell proliferation. This effect, which was seen for concentrations as low as 0.1 micrograms/ml, was HA specific and was not observed with other glycosaminoglycans. When primary cultures were performed in the presence of hyaluronidase-digested or HA-depleted (by passage on a HN column) fetal calf serum, the total number of O-2A lineage cells was dramatically increased (100%, p < 10(-4)) in comparison with control cultures in standard fetal calf serum. Platelet-derived growth factor increased the total number of O-2A lineage cells and of (Galc+) oligodendrocytes. This effect was opposed by HA dose dependently. The effect of HA was significantly inhibited by HN (30%, p < 10(-4)). HN had, however, no effect when it was added to culture in the presence of hyaluronidase in fetal calf serum, suggesting its effect was only due to its binding to HA. During cell maturation, HA disappears as HN appears. This and the fact that HA and PDGF have opposite effects suggest an effect of these factors, or of their balance, on myelination.

Animals↗
PubMed1994

Abnormal cortical plate (polymicrogyria), heterotopias and brain damage in monozygous twins.

We report 5 cases of abnormal cortical plate (polymicrogyria or microgyric-like pattern) and heterotopias associated with hypoxic-ischemic brain injuries in monochorionic diamniotic twin fetuses of respectively 22, 26, 28, 31, 32 weeks gestation. These fetuses belonged to a series of 5 pairs of patients (10 cases) presenting with the characteristic features of the twin-to-twin transfusion syndrome. Three of them (2 donors and 1 recipient) were macerated and the brains were not available for study. Two (most likely recipient twins) survived. In the remaining 5 fetuses (3 donors and 2 recipients) with neuropathological study there were cortical plate abnormalities. In 2 cases, the cortex was dysmorphic and consisted of focal nodular distribution or vertical stripes of neurons. True polymicrogyria was focal in 2 cases and involved almost the entire surface of the hemispheres in another one. Heterotopias of immature cells were found in 4 cases, either in the white matter or in the cortex or in both sites. There was a focal laminar necrosis only in 2 cases. The morphological pattern of the anomalies depends on the time of occurrence of the insult and on its severity. These abnormalities, although similar to those already described in singleton fetuses, illustrate the variety of cortical dysmorphia which may be associated with fetal hypoxic-ischemic injuries and emphasize the particular vulnerability of the brain in monozygotic twins, whether it belongs to the donor or the recipient.

Abnormalities, Multiple↗