Biomedical subjects
Publications and source records attributed to M Bonnet.
Three cases of acute myeloblastic leukemia of FAB-M2 type revealed by an isolated otitis media are reported. This mean of revelation is valuable for early diagnosis and treatment of the disease. A karyotype was performed in two cases and showed an 8;21 translocation. As far as we know, these are the first acute myeloblastic leukemia cases with otitis media reported in which an 8;21 translocation was detected.
The influence of hyperosmolarity on superoxide production by polymorphonuclear leukocytes (PMNL) was examined using NaCl and urea as osmotic substances. Superoxide production was inhibited in a hyperosmotic environment produced by high concentrations of these substances with the following IC50: 440 +/- 75 (SD) mOsm/kg for NaCl and 660 +/- 100 for urea. In the case of NaCl, this inhibition was time-dependent and abolished at 4 degrees C. Since PMNL pump out Na+ ion for maintenance of cellular volume in an energy dependent fashion, it was suggested that the inhibition of superoxide production was due to the exhaustion of energy stores. On the other hand, urea inhibition was almost immediate and remained even when preincubation was performed at 4 degrees C. Because the transport of urea through the cell membrane is known to be energy independent, these findings suggested that urea was either an inhibitor of the NADPH oxidase or a scavenger of superoxide anion.
A prospective clinical study was conducted to determine wether preoperative proliferative vitreoretinopathy (PVR), grade B, was a significant risk factor in the development of severe PVR after surgery for retinal detachment repair. Two series of consecutive retinal detachments associated with horseshoe retinal tears were compared. The first series included 40 eyes of 40 patients with preoperative PVR, grade O-A. The second series included 30 eyes of 27 patients with preoperative PVR, grade B. All eyes were operated on with conventional microsurgical techniques. At the first operation, no vitrectomies were carried out in any eyes. The incidence of postoperative PVR, grades C and D, was 20% (6/30 eyes) after a single operation in the series of eyes with preoperative PVR, grade B as compared to 0% in the series of eyes with preoperative PVR, grade O-A. The difference between the two groups was statistically significant (P = 0.01). It was also found that the incidence of postoperative proliferative PVR was significantly higher in eyes with preoperative vitreous hemorrhage (30.7%) as compared to eyes with no preoperative vitreous hemorrhage (0%; P = 0.02). Incomplete posterior vitreous detachment without collapse of the vitreous gel occurred significantly more frequently in eyes with preoperative proliferative vitreoretinopathy, grade B (68.4%, than in eyes with preoperative proliferative vitreoretinopathy, grade O-A (27.5%; P = 0.02).
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A retrospective study was conducted on a series of 28 eyes with primary retinal tears associated with vitreous hemorrhage. At initial presentation, the retina was detached in 17 eyes and attached in 11. In the series of eyes with an attached retina, the vitreous hemorrhage was massive in 5 eyes (45%), the average number of retinal tears was 1.36. All eyes showed a retinal tear located in the upper quadrants. Three patients (27%) experienced recurrent vitreous hemorrhage after sealing of the retinal tears. In the series of eyes with a detached retina, the vitreous hemorrhage was massive in 5 eyes (29%) and the average number of retinal tears was 1.9. The retinal detachment was located in the upper quadrants in 16 eyes (94%). Clinical evidence of proliferative vitreoretinopathy was noted, at initial presentation, in 6 eyes (35%). Permanent retinal reattachment was achieved in only 12 eyes (70%). All surgical failures were related to proliferative vitreoretinopathy. In the present series the prognosis of primary retinal tears with significant vitreous hemorrhage was guarded because of recurrent vitreous hemorrhages. The prognosis of primary rhegmatogenous retinal detachments with significant vitreous hemorrhage at initial presentation was guarded because of the high incidence of proliferative vitreoretinopathy.
The authors report the case of 5 1/2 year-old boy with insulin-dependent diabetes mellitus revealed during the induction therapy of an acute leukemia of the mixed type, and who presented with an unusual type of pulmonary fungal infection: mucormycosis. It had a favourable outcome with surgical excision preceded and followed by amphotericin B treatment.
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A single-step technique for fluid-gas exchange with pure perfluoropropane gas in proliferative vitreoretinopathy (PVR) is described. The technique was used in 38 eyes of 38 patients. Permanent and total retinal reattachment, with a minimum follow-up of 6 months after gas disappearance, was achieved in 24 eyes (63%). The anatomical success rate was 80.9% (17/21 eyes) in PVR grade C and 41% (7/17 eyes) in PVR grade D. Twenty-two of the successful eyes (92%) underwent a single operation. Thirteen of the successful eyes (54%) obtained final visual acuities of 0.1 or better. Severe increase of intraocular pressure postoperatively, due to overestimation of the intraocular space available for gas expansion, is a potential risk of the technique. This risk should be avoided by means of preoperative evaluation of the vitreous cavity volume with A-scan ultrasonography and intraoperative measurement of the intraocular fluid volume displaced by scleral buckling.
In our hospital, 62 retinal detachments (RDs) in 58 patients who had previously been subjected to prophylactic argon laser photocoagulation (ALP), were operated on between July 1980 and October 1985. The incidence of RDs after prophylactic ALP has increased in recent years, being 3.90% (10 out of 256 RDs) in 1982, and 12.09% (26 out of 215 RDs) in 1985. The time interval between ALP and the occurrence of RD was less than 1 year in 54.7% of the patients, and between 1 and more than 10 years in 45.3%. Fifty per cent of the RDs developed after prophylactic ALP of retinal breaks. Fifty per cent of the RDs occurred after prophylactic treatment of degenerative lesions of the peripheral retina; 77% of the RDs in this last group occurred in eyes that had been subjected to 360 degrees photocoagulation. From the data obtained from the present series, the value of the 360 degrees technique for prophylactic ALP would appear to be rather questionable in most cases. In the present series, most RDs occurring after prophylactic ALP did not appear to be less severe than RDs in eyes that had not been subjected to prophylactic treatment.
Nine eyes in nine patients with rhegmatogenous retinal detachments of 1-18 years, duration showed clinical evidence of significant retinal neovascularization in the equatorial region. The retinal new vessels showed a sea-fan configuration. Their extent in the periphery of the fundus ranged from 10 degrees to 180 degrees. All retinal detachments were associated with round atrophic retinal holes in the equatorial region. Retinal reattachment was achieved in all eyes with scleral buckling. The retinal new vessels totally regressed within 15 days to 3 months after retinal reattachment. It is believed that the peripheral retinal new vessels were secondary to retinal hypoxia resulting from decreased retinal blood flow in the detached retina.
The binding of 3H-labeled serotonin (or 5-hydroxytryptamine: 5HT) to mouse lymphocytes was investigated. It was shown to be highly specific, time-dependent, saturable and partly reversible. Saturation analysis demonstrated a Kd of 198 nM and B max of 3.53 nM. We studied receptor specificity by using different types of serotonin antagonists, and numerous other substances. Serotonin was found to be the most effective drug among those tested in inhibiting the binding of 3H-5HT, having an IC50 of 194 nM. The fact that 5HTP, a 5HT precursor, had no inhibitory capacity indicated the high specificity of these 5HT binding sites. Dopamine was somewhat able to competitively inhibit 5HT fixation (IC50 = 27,000 nM), whereas norepinephrine and histamine had no effect. Lastly, we investigated the cellular specificity of this binding, and observed that nonmacrophage peritoneal cells extensively bound serotonin under the same conditions as spleen cells. This is the first direct demonstration of 5-hydroxytryptamine receptors on mouse lymphocytes. The presence of these binding sites can contribute to the understanding of the suppressive effect of 5HT on mouse immunoreactivity.
Heavy cryotreatment of the fibrous ingrowth remnants at the inner surface of the scleral wound was performed, as an adjunct to vitreo retinal microsurgery, in a series of 32 eyes affected with retinal detachment after penetrating scleral wound. Surgical success, with a follow-up of 6-42 months after gas disappearance, was achieved in 25 eyes (71%). However, permanent retinal reattachment was achieved with a single operation in only 64% of the eyes successfully operated on (16/25). Thirty-six per cent (9/25 eyes) of the retinal detachments that were eventually successfully operated on showed clinical evidence of gradual contraction of the vitreous base in the postoperative course, and required 2 or more operations. Experimental studies on standardized models are required to determine whether destruction of the fibrous ingrowth remnants with heavy cryo is of any value in the management of retinal detachment after penetrating scleral wound.
Microsurgery for RD repair has brought about significant improvement in the management of easy RD as well as difficult and desperate cases. At present, prevention of severe PVR remains the only major problem in the management of rhegmatogenous RD.