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Biomedical subjects

P Page

Publications and source records attributed to P Page.

At least 37 records · Page 2Linked to original sources
PubMed1998

The synthesis of symmetrical spermine conjugates using solid-phase chemistry.

The utility of spermine, selectively functionalised and immobilised on a solid support by means of the Wang "oxycarbonyl" linker is demonstrated by the solid-phase synthesis of a number of spermine conjugates including the natural product and potent antihypertensive agent kukoamine. The synthesis opens up the area of solid-phase spermine chemistry and library generation based on the symmetrical spermine scaffold.

Chromatography, High Pressure Liquid↗
PubMed1998

[The place of radiosurgery in the treatment of hypophyseal adenoma].

Since 1984, the neurosurgical team of Sainte-Anne Hospital in Paris has taken in charge almost 750 patients for linear accelerator radiosurgery. But only a small percentage of them were harbouring a pituitary tumor. That is why the present paper is based mostly on literature data. Pituitary adenoma radiosurgery (RS) is a second intention therapeutic method. It should be recommended only after failure of medical and/or surgical treatment. Two main methods can be used: linear accelerator-radiosurgery and Cobalt-60 gamma unit. Both procedures provide equivalent results in terms of dosimetry, accuracy and clinical data. Results of various series presented in recent and updated literature have been studied and analysed. They show and confirm the efficiency of radiosurgery on tumor and hormone secretion controls, with few cases of pituitary insufficiency. However, results were disappointing concerning visual disorders, particularly if visual dysfunction and impairment existed before radiosurgery. All authors agree nowadays on different points: a) indications: invasive adenomas, with an incomplete resection, or adenomatous recurrences, b) contraindications: tumoral size > 20 mm, distance to visual pathways < 5 mm, c) imperative precautionary measures: less than 8 Gray must be delivered on visual pathways, less than 40 Gray on oculomotor nerves. In some cases, stereotactic fractioned radiotherapy may be an alternative treatment for large tumors close to visual pathways.

Adenoma↗
PubMed1998

[Intracavernous extension of hypophyseal macroadenomas: infiltration or invagination?].

Frequency of intracavernous invasion by a pituitary adenoma varies from 9% to 40% depending on the publications. Without putting off the possibility of true intracavernous invasion, it seems less frequent than evocated on CT-Scan and/or MRI data. We studied 153 files of pituitary adenomas operated upon recently: 72 prolactinomas (47.3%), 30 GH-secreting adenomas (19.7%), 7 corticotrop adenomas (4.6%), 44 non secreting adenomas (28.3%). 108 patients (70.4%) harboured a macroadenoma (diameter > 10 mm). A suprasellar expansion was seen 90 times on CT-Scan and/or MRI views. 19 times (17.7% of macroadenomas, 12.5% of the whole series) MRI evocated an infiltration of one or both cavernous sinuses (CS). Such data were found 3 times before 1991, 16 times since 1991, i.e. since MRI is systematically performed preoperatively. Except in two patients who respectively presented with a large intraorbital or temporal expansion, we have not been able to confirm the reality of the intracavernous invasion. We think that most of CT-Scan or MRI data of so-called intracavernous invasion correspond in fact to a compression or to a fingerglove invagination of the medial wall of the CS. In fact, anatomical studies by Harris & Rhoton (1976) and by Taptas (1990) demonstrated that such an invagination of the medial wall exists in almost one third of normal pituitary glands. These data must bring up to much carefulness when considering a possible pathological CS invasion by a macroadenoma. Therefore, it should be thoroughly assessed with anatomoradiological and radio-surgical correlations.

Adenoma↗
PubMed1998

[Controversies in the management of operated pituitary macroadenomas].

BACKGROUND AND PURPOSE: Complete resection of a pituitary adenoma is feasible in almost 50 to 70% of cases. Dealing with the remnant is still controversial. Three positions can be discussed: second stage operation, radiation therapy, clinical and radiological follow-up. METHODS: Among 108 pituitary macroadenomas operated on during the last 10 years, 54 patients (50%) with partially removed tumors were studied. Three cases best illustrating the evolution of these remnants are reported. RESULTS: Late MRI performed 4 to 6 months postoperatively is more valuable than early MRI in the evaluation of these remnants, which can remain stable for a long period of time without any adjuvant treatment. CONCLUSION: MRI should be performed 4 to 6 months postoperatively. Rather than performing radiation therapy systematically for asymptomatic patients, these patients should be followed up at regular intervals and treated only in case of regrowth of the tumor.

Adenoma↗
PubMed1997

[Prognostic factors and primary cerebral lymphoma].

Therapeutic results of 248 patients with primary central nervous system lymphoma reported in the SFNC series between 1980 and 1995 were analyzed. Clinical, biological and radiological prognostic factors were found to have a favorable impact on survival: a) age < 60 years; b) radiation therapy but without evidence of a dose-response relationship; c) radiation therapy in addition to chemotherapy; d) the use of systemic chemotherapy consisting of anthracyclines. In multivariate analysis, we identified 4 independent factors: a) radiotherapy (RR = 3), b) age (RR = 2.31), c) the use of chemotherapy consisting of anthracyclines (RR = 2.53), d) partial surgical resection but as an unfavourable prognostic factor (RR = 1.45).

Age Factors↗
PubMed1995

Pathophysiology of acute exercise-induced muscular injury: clinical implications.

Acute muscular injury is the most common injury affecting athletes and those participating in exercise. Nearly everyone has experienced soreness after unaccustomed or intense exercise. Clinically, acute strains and delayed-onset muscle soreness are very similar. The purpose of this paper is to review the predisposing factors, mechanisms of injury, structural changes, and biochemical changes associated with these injuries. Laboratory and clinical findings are discussed to help athletic trainers differentiate between the two conditions and to provide a background knowledge for evaluation, prevention, and treatment of exercise-induced muscular injury.

Journal Article↗
PubMed1995

[Identification of deep septal ventricular tachycardia substrates from epicardial breakthrough characteristics].

This study aimed to elucidate the relationship between the epicardial activation pattern and the site of origin of the ventricular tachycardia (VT) occurring from the interventricular septum, and to find epicardial breakthrough characteristics identifying VT substrates. Seven patients undergoing intraoperative mapping including right ventricular endocardial mapping were studied. Thirteen septal VTs, which were defined as VTs in which both right and left ventricular endocardial breakthroughs were on the septal aspect, were induced. The VT site of origin was identified from the site and timing of right and left septal endocardial breakthroughs. All VTs were classified into three groups according to the site of epicardial breakthrough: type A, epicardial breakthrough in the anterior interventricular area; type F, epicardial breakthrough in the right ventricular free wall; type P, epicardial breakthrough in the posterior interventricular area. All type F VTs had a right ventricular endocardial breakthrough in the anterior septum and preceded the left ventricular endocardial breakthrough, thereby indicating right anterior septal origin. In the types A and P, both the right and left endocardial breakthroughs were localized in consistent (anterior and posterior, respectively) halves of the septum, but their relative timing was inconstant. This result suggests that epicardial mapping, and even noninvasive methods like body surface mapping, can identify the site of origin of the septal VTs, especially when the epicardial breakthrough occurs in the right ventricular free wall.

Aged↗
PubMed1991

Perioperative autotransfusion and its correlation to hemostasis and coagulopathies.

The use of autologous blood techniques affords the reduction or elimination of homologous blood transfusions for most patients. In addition, for certain religious faiths such as Jehovah's Witnesses or those patients with rare blood types, intraoperative salvage and return of the patient's own blood is the only source of available blood. Autologous blood salvage in the perioperative period includes: hemodilution; intraoperative salvage of lost blood; postoperative collection of shed blood. Perioperatively, autologous blood is salvaged and returned and the volumes involved do not create any hematological problems for the patient. In those cases involving large volumes of blood being processed and returned to the patient, the autotransfusionist must be aware of the possible alterations that may occur in the patient's coagulation system. The collection and reinfusion of wound drainage fluids from operative sites has the potential to cause severe bleeding problems. This paper will present an overview of autologous blood salvage techniques in the perioperative period along with a review of the clinical effects of autotransfusion on hemostasis. Also discussed will be possible coagulopathies that can be caused by returning collected autologous blood.

Blood Coagulation↗
PubMed1990

[Percutaneous angioscopy in the diagnosis of arteriopathies of the lower limbs].

Because of the poor specificity of the arteriography, the authors have performed a percutaneous angioscopy before every angioplasty of the arteries of lower limbs for nearly 3 years. They define the angioscopy and describe materials and technique. The percutaneous route without surgery and without anesthesia underlines the originality of the technique. The great difficulty is to counter-pulse the arterial inflow. The rate of saline irrigation and all the means of arterial blockade are described. In the second part, the "elementary images" are classified. The authors insist on the specificity of the angioscopy in the interpretation of arterial obstructions. Because of this specificity, the right treatment can be applied to any type of lesion. Angioscopy permits to foresee endoluminal surgery technique.

Angiography↗
PubMed1989

Activities, family relationships and feelings about aging in a multicultural elderly sample.

This study looked at ethnic and gender differences in activities, family relationships, and feelings about aging in 128 American Indian, Anglo, and Hispanic adults over sixty. Reading, visiting, and watching television were the most popular activities for all subjects, with a number of sex and ethnic differences appearing. Most subjects reported improved relationships with their families on various dimensions after turning sixty. A number of advantages and disadvantages of aging were mentioned. Few ethnic or gender differences were found on these latter variables.

Activities of Daily Living↗
PubMed1988

Anisotropic conduction and functional dissociation of ischemic tissue during reentrant ventricular tachycardia in canine myocardial infarction.

We measured the conduction characteristics at the epicardial surface of the left anterior ventricular wall in the in situ canine heart before and 3 to 5 days (n = 9 dogs) after permanent occlusion of the left anterior descending coronary artery (LAD). During ventricular stimulation generating wavefronts conducted along the longitudinal or the transverse fiber direction, 61 unipolar electrograms were recorded with a fine-meshed plaque electrode. Before occlusion, the fastest conduction velocity was consistently found in a direction perpendicular to the nearby LAD segment (longitudinal direction), and the slowest velocity in a direction parallel to the LAD segment (transverse fiber direction). In 3- to 5-day-old infarct preparations, a layer of subepicardial muscle with 1 to 3 mm thickness survived over necrotic tissue. The velocities and directions of fast and of slow conduction measured in ischemic subepicardial muscle were not significantly different from preocclusion values during stimulation at a basic rate, but excitability was found to be depressed in response to premature stimuli. Premature impulses initiated in nonischemic myocardium and conducted into ischemic tissue in the longitudinal or in the transverse directions induced sustained (greater than 100 beats) monomorphic tachycardias during which figure-eight activation patterns were mapped with sock-array electrodes. During these tachycardias, the direction of the common reentrant wavefront of the figure-eight pattern was preferentially oriented along the longitudinal fiber direction, independently of the direction of the initiating impulse. When polymorphic beats were induced, tachycardia terminated spontaneously within 20 beats, or changed to a monomorphic pattern, as described above. In conclusion, the anisotropic organization of surviving subepicardial muscle overlying an infarct provides a spatial constraint that determines a preferential direction of reentrant propagation and may contribute to sustaining monomorphic tachycardia.

Animals↗