Biomedical subjects
Publications and source records attributed to J M Basset.
Explore the source record for details and available documents.
The reactions of CpZr(CH(3))(3), 1, and Cp(2)Zr(CH(3))(2), 2, with partially dehydroxylated silica, silica-alumina, and alumina surfaces have been carried out with careful identification of the resulting surface organometallic complexes in order to probe the relationship between catalyst structure and polymerization activity. The characterization of the supported complexes has been achieved in most cases by in situ infrared spectroscopy, surface microanalysis, qualitative and quantitative analysis of evolved gases during surface reactions with labeled surface, solid state (1)H and (13)C NMR using (13)C-enriched compounds, and EXAFS. 1 and 2 react with silica(500) and silica-alumina(500) by simple protonolysis of one Zr-Me bond by surface silanols with formation of a single well-defined neutral compound. In the case of silica-alumina, a fraction of the supported complexes exhibits some interactions with electronically unsaturated surface aluminum sites. 1 and 2 also react with the hydroxyl groups of gamma-alumina(500), leading to several surface structures. Correlation between EXAFS and (13)C NMR data suggests, in short, two main surface structures having different environments for the methyl group: [Al](3)-OZrCp(CH(3))(2) and [Al](2)-OZrCp(CH(3))(mu-CH(3))-[Al] for the monoCp series and [Al](2)-OZrCp(2)(CH(3)) and [Al]-OZrCp(2)(mu-CH(3))-[Al] for the bisCp series. Ethylene polymerization has been carried out with all the supported complexes under various reaction conditions. Silica-supported catalysts in the absence of any cocatalyst exhibited no activity whatsoever for ethylene polymerization. When the oxide contained Lewis acidic sites, the resulting surface species were active. The activity, although improved by the presence of additional cocatalysts, remained very low by comparison with that of the homogeneous metallocene systems. This trend has been interpreted on the basis of various possible parameters, including the (p-pi)-(d-pi) back-donation of surface oxygen atoms to the zirconium center.
Explore the source record for details and available documents.
The hydrogenolysis of cyclohexane catalyzed by supported Ir/SiO(2) has been studied to get mechanistic information on the elementary steps of C--C bond cleavage for cyclic saturated hydrocarbons. The reaction was studied under conditions in which no dehydrogenation to benzene occurs. When a mixture of cyclohexane and H(2) flows over a Ir/SiO(2) catalyst at 200 degrees C and for a H(2)/cyclohexane ratio superior to 40, methane, ethane, propane, n-butane, n-pentane, and n-hexane are identified to be primary products. The hydrogenolysis of ethane and n-hexane has also been studied to clarify several mechanistic questions. To account for the primary products in the above reactions, a mechanism is proposed in which the key step of the carbon--carbon bond cleavage occurs via concerted electronic transfer in dimetallacyclopentane intermediate. The comparison of product distributions in the hydrogenolysis of cyclohexane and that observed for n-hexane led to conclusions about the relative ease of carbon--carbon bond cleavage with respect to surface alkyl isomerization.
After a brief summary of the technique used for myringoplasty (enlarged endaural approach, large flattened aponeurotic graft applied to deep surface of tympano-meatal flap after a "request" for boring) emphasis is given to the need for strict surveillance and postoperative care by the surgeon. Immediate postoperative care starts in the operating room and involves a deep intra-meatal dressing (1 or 2 Popes oto-wicks placed on a thin film of silastic or simply surrounded by Gelfoam) and a superficial dressing. The dressing is renewed on the 3rd day with the patient in bed and involves only the superficial one. Secondary postoperative care extends to the 10th or 15th day and includes exeresis of the deep pope-Gelfoam assemblage under careful binocular microscope control followed by audiometric examination. Hospital stay is a mean of 5 days and medical treatment (antibiotics, vasodilators, corticoids) is given as required. Late postoperative care can be summarized as involving regular surveillance and the application of certain rules that cause little disturbance in the patients life. Various rare and even exceptional incidents, benign in the majority of cases, are reviewed.
Explore the source record for details and available documents.
The authors report 15 cases collected over a period of 13 years (1972 - 1984) of a particularly serious eventuality affecting certain evacuation cavities: Early recurrence of diffuse hypertrophic osteitis (E.R.D.H.O.). This is a rare complication, occurring in 1.5% of cases of chronic otitis. However, the fact of having operated upon 7 cases in 1984 alone, whilst during the previous 12 years, only 8 had been seen, raised the alarm. The classical pattern of this complication occurs in 3 stages, each involving surgical operation: at the outset, chronic otitis with cholesteatoma or osteitis, most often mixed, for which an "inadequate" surgical procedure is performed. then, after a variable period which may exceed 10 years, a very large evacuation cavity was created by the authors. finally, 3rd and final stage: within 6 months, this cavity filled progressively and, at operation, the authors discovered a cavity virtually completely filled with a "fantastic" "moist sugar" osteitis, requiring a new evacuation cavity, even larger than that created before. In all cases, a successful result was obtained within a varying period, sometimes accompanied by spectacular improvement in general condition. The most plausible etiopathogenic hypothesis advanced to attempt to explain this phenomenon is that of secondary infection by a varied microbial flora, including, on the one hand, aerobic organisms usually discovered in such cases (pseudomonas pyocyaneus, proteus mirabilis) and, secondly, this being of essential importance, "anaerobic" bacteria, the bacteriological diagnosis of which requires application of a strict protocol. The authors have taken three decisions following their bibliographic investigations.(ABSTRACT TRUNCATED AT 250 WORDS)
The authors report 27 new cases of osteomatous chronic otitis, with (15) or without (12) cholesteatomas, with perforated (13) or intact (14) drum, the latter sometimes having a very atypical appearance (2), frankly purulent or simply inflammatory. This results in a wide range of clinical appearances. There are two macroscopic forms: the diffuse attico-antral form and localized forms (drum - C.S.C.L.). The authors emphasize: the primordial interest of tomography (or CT scan), the keystone of their discovery, as well as the dangers of their surgical treatment. In addition to review of these known concepts, two forms have been identified: 1) Osteomatous attico-chain monoblock, where the ossicles of the ear are adherent in their entirety, either to the external attical wall or, much more rarely, to the medial attical wall. They describe 13 cases, the pattern of which is very different, according to whether the diagnosis is one of cholesteatomatous chronic otitis or not. In the absence of cholesteatoma (8 cases), the clinical picture is suggestive of otospongiosis or of chronic otitis with intact drum. The surgical procedure is related to these findings: 1 completion of myringoplasty, 7 piston-malleus. In cases of cholesteatomatous chronic otitis (5 cases), the picture is completely different, the cholesteatoma developing at leisure, behind the impenetrable osteomatous shield. Once again, the surgical procedure is modified: 4 vast evacuation cavities and one mastoatticotomy for giant cholesteatoma with intact drum. 2) Diffuse and "progressive" osteomatous stenosis of the walls of the E.A.M. The authors describe 6 cases occurring either during cholesteatomatous chronic otitis, or within a few weeks, simulating chronic otitis with intact drum.
44 cases of tympanic involvement in the context of chronic otitis are described. 34 occurred during active chronic otitis. This is a rare possibility (approximately 4% of our own cases of chronic otitis). The following may be mentioned amongst them: 21 cases of osteitis, for which the following concepts should be borne in mind: the extreme severity of the chronic otitis responsible, in most instances, ears which had undergone multiple surgery (17/21), lesions exclusively of osteitis, but very extensive in 2/3 of cases (14/21). 7 cases of osteolytic disease, occurring severe or atypical cholesteatomatous chronic otitis and quite often involving associated osteolysis affecting the main VII, the promontory, the bulb of the internal jugular vein, or even the carotid canal. 4 cases of diffuse sub-obstructive osteomatous disease of the walls of the E.A.M., "progressive" development of which over several months was noted in 3 cases. Finally, 2 cases of mixed disease: (osteitis--osteomatoma and osteitis--osteolysis). 8 cases occurred following myringoplasty: this is a rare eventuality (approximately 1%), 1 case only of osteolysis due to iatrogenic cholesteatoma, 7 cases of osteitis, either highly localized and not preventing further myringoplasty (4 cases), or very extensive, finally resulting in a vast evacuation cavity. In 2 cases, a malformation is the origin of involvement of the tympanic at the origin of chronic otitis was felt probable, without it being possible to reach any definite conclusion concerning auriculobranchial fistula or Huschke foramen.
The authors undertook a study of changes in bone conduction (BC) during 800 operations carried out over a 5 years period (1979-1984) for chronic otitis or sequelae of chronic otitis. After elimination of ears with deafness (47) and cases unsuitable for evaluation (39), they finally included 714 records in the study. Only comparison of free and post-operative BC was made and using 4 conversational frequencies, not taking into account a deviation of 5 DB for each of these 4 frequencies. The study involved 317 myringoplasties: In 271 (i.e. 85,5%) there was no change in BC. Amongst them, 37 patients nevertheless showed a transient fall in BC. Of particular importance is the fact that almost 1/3 (11 to be exact) recovered only during the 2nd semester following surgery, a period which was even exceeded in the other 5 cases. 46 (i.e. 14.5%) were classified as "permanent" falls in BC. Amongst these in only 17 (i.e. 5%) were there "only" the three standard aggression factors for the I.O.: aspiration--scraping--manipulation of the tympano-ossicular system, without it being possible to attribute a predominant role to one more than the other. With regard to reaming of the E.A.M., those cases in which this could be considered responsible appeared to be infinitesimal. Furthermore, there was no statistically significant difference (reduced deviation test--"chi"2 test) between the number of falls in BC seen following myringoplasty with or without reaming. 83 tympanoplasties by Piston-Malleus, study of which led to the same conclusions as for myringoplasties. 118 masto-atticotomies, including 23 with posterior tympanotomy. Despite peri-labyrinthine and peri-ossicular scraping, results were essentially identical. 196 evacuation cavities (227-31 deafness) of which somewhat less than half only (46%) were ears undergoing surgery for the first time. Percentage of unchanged BC was here much more unfavourable, with 49 "permanent" falls in BC, i.e. 25%, of which, it must be said, 5 were minimal falls, and with, in 25 cases, a follow-up of less than 3 months.
Explore the source record for details and available documents.
Fourteen cases of Ewing's inversed papilloma of the nose and sinuses were treated as primary lesions or after recurrence. Clinical and paraclinical, mainly radiologic, endoscopic, and biologic investigations are of fundamental importance and should be as extensive for primary as for recurrent lesions. Treatment is largely dependent on the results of these examinations, is essentially surgical, and should respond to two imperatives. First, it should lead to total excision under the best possible conditions, and second, it should involve a minimum of sequelae, particular esthetic complications. Techniques for excision through the natural pathways are described, followed by those using an external approach (canine fossa or para-lateronasal approaches), as well as their advantages and inconveniences. The preferred procedure is through an open, wide, para-lateronasal approach, enabling the most effective excision to be performed, this technique appearing to be essential for recurrent lesions.
The authors report the observation of two cases of benign schwannomas, one in the nasal cavities, the other in the maxillary sinus and a case of odontogenous fibromyxoma of the ethmoïdo-maxillary sinus. After a study of the observations, a literature review determines the benign character of these tumours, the possibilities of recurring in case of incomplete operation, the importance of computerized tomography to precise their extension, the histological difficulty of the diagnosis and the importance of ultrastructural study to identify them. Taking the cases of schwannomas, we settle two forms A and B (ie) Antoni, because of the myxoïde degeneration which predominate in the second type. Concerning the fibromyxomas histochemicals and ultrastructural studies allow us to definite the character of "myxoblast" or "fibroblast", Cells. Treatment of these lesions is essentially surgical and a long term prognosis is favourable.
The cases of laryngeal tumors requiring surgical excision are presented. The first case was that of patient with a laryngeal lipoma of atypical appearance, histological findings suggesting a hamartoma. The second patient had a chemodectoma, diagnosis being difficult but facilitated by super-selective arteriography, requiring delicate excision which was almost bloodless as a result of previous embolization. Clinical and pathological features of these tumors reviewed, and problems related to their treatment discussed. The authors have previously reported 4 other rare types of laryngeal tumor.
Two further cases of a meningioma of the ear simulating a glomus tumor are reported, pathological features in the first case leading to intensive discussion. Two such cases had been previously described in great detail in a paper published in 1977. In those patients, the differential diagnosis froma jugular glomus tumor was only established two and a half years later in one case, when excision was necessary because of an intracranial recurrence, and following-re-examination of all sections of jugular glomus tumors previously operated upon, in the other case. Factors enabling detection of meningiomas simulating glomus tumors were also discussed in the original report. Theses included discordance of clinical finding, -minimal signs on arteriography, -the primordial value of contrast computed tomography, -systematic alerting of the pathologist.
Explore the source record for details and available documents.
The value of high frequency ventilation employing the inter-cricothyroid approach was assessed during general anesthesia for endoscopic examination of the upper respiratory tract passages. The technique for introducing the inter-cricothyroid canula, and the ventilatory apparatus, are described, and results exposed as a function of local effects of puncture and the quality of pulmonary ventilation obtained. Advantages, and other indications for the use of this technique, are discussed.
Ten elderly patients with subacute or chronic mastoiditis, including 5 with a complication Bell's palsy, were treated. 1) mastoid infections in elderly patients can present the typical characteristics as seen in younger subjects, this being the case in 4 of the 10 cases. 2) The findings in the other 6 patients confirmed facts, that are known or suspected, relating to the sometimes extremely serious and rapidly progressive nature of the affection, due to almost total lack of defences of the organism in elderly patients, often also diabetic, where the causal germ was invariably pyocanic. 3) In 3 cases, after removal of large amounts of wax with great difficulty, there was the very rapid development of a true malignant otitis externa with a Bell's palsy, and extensive bone involvement extending well beyond the region of the tympanic cavity.