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B Morin

Publications and source records attributed to B Morin.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effect of chronic renal failure on the expression of erythropoietin message in a murine model.

The anemia of chronic renal failure (CRF) is largely due to decreased production of erythropoietin (EPO) by the kidney. A small amount of EPO also originates from extra-renal sources, and this would be expected to assume a more important role in maintaining erythropoiesis when renal production is impaired. In this study, we examined the production of EPO mRNA by RT-PCR in kidney, liver, and bone marrow tissues isolated from normal mice, mice rendered acutely anemic by phlebotomy, and from mice with surgically induced CRF. The induction of acute anemia results in an expected increase in the expression of EPO mRNA in renal and hepatic tissue. In contrast, while the expression of EPO mRNA was expectedly reduced in the kidney from CRF mice, it was completely absent in the liver of these same animals. EPO mRNA expression was also absent in the bone marrow in both states of acute anemia and CRF. These results show that CRF can directly or indirectly can suppress the extrarenal production of EPO by the liver and that this effect may further aggravate the anemia of CRF.

Anemia↗
PubMed1995

Photooxidation of d(TpG) by riboflavin and methylene blue. Isolation and characterization of thymidylyl-(3',5')-2-amino-5-[(2-deoxy-beta-D- erythro-pentofuranosyl)amino]-4H-imidazol-4-one and its primary decomposition product thymidylyl-(3',5')-2,2-diamino-4-[(2-deoxy-beta-D- erythro-pentofuranosyl)amino]-5(2H)-oxazolone.

The major initial product of riboflavin- and methylene blue-mediated photosensitization of 2'-deoxyguanosine (dG) in oxygen-saturated aqueous solution has previously been identified as 2-amino-5-[(2-deoxy-beta-D-erythro-pentofuranosyl)amino] 4H-imidazol-4-one (dlz). At room temperature in aqueous solution dlz decomposes quantitatively to 2,2-diamino-4-[(2-deoxy-beta-D-erythro- pentofuranosyl)amino]-5(2H)-oxazolone (dZ). The data presented here show that the same guanine photooxidation products are generated following riboflavin- and methylene blue-mediated photosensitization of thymidylyl-(3',5')-2'-deoxyguanosine [d(TpG)]. As observed for the monomers, the initial product, thymidylyl-(3',5')-2-amino-5-[(2-deoxy- beta-D-erythro-pentofuranosyl)amino]-4H-imidazol-4-one [d(Tplz)], decomposes in aqueous solution at room temperature to thymidylyl-(3',5')-2,2-diamino-4- [(2-deoxy-beta-D-erythro-pentofuranosyl)amino]-5(2H)-oxazolone [d(TpZ)]. Both modified dinucleoside monophosphates have been isolated by HPLC and characterized by proton NMR spectrometry, fast atom bombardment mass spectrometry, chemical analyses and enzymatic digestions. Among the chemical and enzymatic properties of these modified dinucleoside monophosphates are: (i) d(Tplz) and d(TpZ) are alkali-labile; (ii) d(Tplz) reacts with methoxyamine, while d(TpZ) is unreactive; (iii) d(Tplz) is digested by snake venom phosphodiesterase, while d(TpZ) is unaffected; (iv) relative to d(TpG), d(TpZ) and d(Tplz) are slowly digested by spleen phosphodiesterase; (v) d(Tplz) and d(TpZ) can be 5'-phosphorylated by T4 polynucleotide kinase. The first observation suggests that dlz and dZ may be responsible for some of the strand breaks detected following hot piperidine treatment of DNA exposed to photosensitizers.

Bacteriophage T4↗
PubMed1994

Benzophenone photosensitization of 2'-deoxyguanosine: characterization of the 2R and 2S diastereoisomers of 1-(2-deoxy-beta-D-erythro-pentofuranosyl)- 2-methoxy-4,5-imidazolidinedione. A model system for the investigation of photosensitized formation of DNA-protein crosslinks.

Benzophenone-mediated photosensitization of 2'-deoxyguanosine and its 3',5'-di-O-acetyl derivative, used as DNA model compounds, in oxygen-saturated water-methanol (1:1) solution results in the nucleophilic addition of methanol to the guanine base. The resulting modified nucleosides have been isolated by reverse-phase high-performance liquid chromatography and characterized by extensive spectroscopic measurements including 13C and 1H nuclear magnetic resonance, fast atom bombardment mass spectrometry and circular dichroism as the 2R and 2S diastereoisomers of 1-(2-deoxy-beta-D-erythro-pentofuranosyl)-2-methoxy-4,5-imidazolinedione and their related 3',5'-di-O-acetyl derivates. Information concerning the absolute configuration of the two pairs of diastereoisomers was inferred from detailed nuclear Overhauser effect experiments. A reaction mechanism, involving guanine radical intermediates, is proposed to explain the generation of these new guanine photoproducts.

Benzophenones↗
PubMed1994

The value of computed tomography for the diagnosis of recurrent patellar subluxation in adolescents.

OBJECTIVE: To determine if computed tomography of the patellofemoral joint has any advantage over standard radiologic techniques in the evaluation of recurrent patellar subluxation. DESIGN: A case series. SETTING: A tertiary children's hospital out-patient clinic. PARTICIPANTS: Forty consecutive adolescents with a clinical diagnosis of recurrent patellar subluxation (study group) and 14 volunteers with normal knees (control group). INTERVENTIONS: A standardized radiologic protocol, including axial views of the patella at 30 degrees of knee flexion, with and without external torsion of the tibia, and computed tomography (CT) of the patella at 15 degrees of knee flexion. MAIN OUTCOME MEASURES: The lateral patellofemoral angle on the axial views and on the CT scan and patellar centralization on the CT scan. RESULTS: In the control group, no radiologic evidence of recurrent patellar subluxation was found. In the study group, an abnormal lateral patellofemoral angle was found in 25% of axial views; this rate increased to 42% with external rotation and 86% on the CT scan. Patellar centralization was abnormal in 79% of cases. CONCLUSIONS: CT of the patellofemoral joint is more sensitive than standard radiographs for the diagnosis of recurrent patellar subluxation. The use of CT is recommended when standard radiographs appear normal.

Adolescent↗
PubMed1990

[Retinal detachment in pseudophakic patients. Apropos of 39 cases].

Pseudophakic Retinal Detachment (PRD) is of major concern, because since 1981, the number of patients receiving implants per year has been higher than that not implanted in the United States. Recently, the number of PRD has exceeded that of Aphakic Retinal Detachment (A.R.D.). This has been observed over the last two years in our unit. We report on 39 cases treated in the unit of Pr METGE between April 1986 and April 1988; P.R.D. characteristics, surgical procedures and anatomic results are presented. We have distinguished 4 types of P.R.D. Differences in prognosis may be imputed to the larger number of undetected tears and the more advanced vitreo-retinal proliferation in PRD as compared with A.R.D. Surgical procedures in PRD are identical with those of A.R.D., and implant may be maintained. Reinterventions, vitrectomy, and internal tamponnement are more frequently needed. The best prognosis observed in our patients occurred for PRD following ECCE + posterior chamber lens without peroperatory complications.

Humans↗
PubMed1990

[Endophthalmia of pseudophakic patients].

After the era of antibiotics, a real improvement has been stated in the percentage of endophthalmis following cataract surgery which has fallen from 1% between 1950 and 1977, to 0.2-0.3% now. Since 10 lenses have been implanted, the incidence of acute bacterial endophthalmitis due to pathogenic organisms has not increased. But we now encounter many cases of "cold endophthalmitis", with a lowered symptomatology, a delayed onset, and which are due to organisms of low virulence. Their prognosis can be improved by early vitrectomy combined to intraocular antibiotics in the more severe cases, and by using antibiotics of high intraocular penetration in the milder cases. We report fifteen cases of pseudophakic endophthalmitis. The clinical course was acute in one case, sub acute in eleven cases, and chronic in three cases. In the latter fourteen cases a vitrectomy was performed in 60% of the cases. Aqueous and vitreous taps have found cocci gram + in five cases. Visual results are superior to 1/20 in 2/3 of the cases.

Acute Disease↗
PubMed1990

Experimental retinectomy in the rabbit.

We developed a model for creating retinectomies of various sizes in phakic rabbit eyes and examined the effects of retinal attachment, epiretinal membrane formation, and intraocular pressure. Eleven retinectomized eyes with an average defect size of 5.6 disc areas and a postoperative followup from 48 to 62 days remained attached without retinopexy, and pigmented scarring involving the photoreceptor/retinal pigment epithelial layers was observed at the margins of the retinectomy. No sign of epiretinal membrane formation was detected by ophthalmoscopic or histologic examination. Postoperative ocular tensions were similar between retinectomized and unoperated control eyes. This experimental study in the avascular rabbit retina suggests that retinectomies do not invariably cause epiretinal membranes or ocular hypotension.

Animals↗
PubMed1989

[Acute bilateral glaucoma in an LAV-positive subject].

A bilateral angle-closure glaucoma is described in a homosexual man, with a positive HIV serology. This angle closure is secondary to an anterior rotation of the ciliary body at the scleral spur following development of an inflammatory cilio-choroidal detachment: which is itself connected with a massive uveal-retinal effusion. The cause of this uveal effusion appears to be cytomegalovirus. This unusual syndrome was the initial manifestation of AIDS (Acquired Immune Deficiency Syndrome). A symptomatologic treatment with cycloplegics and prednisolone and a specific one with DHPG (9-1, 3-dihydroxy-2-propoxymethyl guanine), resulted in rapid regression of the local lesions; his overall clinical condition however deteriorated rapidly over two months following onset of syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Galand disk implant and pupillary block].

We have implanted 530 Galand's disc lens in the last 15 months. Stability and self-centering of implant were good when peroperative vitreous pressure was normal and in any case when wound was closed. Pupillary blocks, specific complications of this lens were rare (less than 1%); they can be prevented occurred by simple and adequate protocols.

Adolescent↗
PubMed1988

Cardiovascular effects of two new calcium antagonists, PY 108-068 and PN 200-110, in conscious spontaneously hypertensive rats.

1. The acute cardiovascular effects of PY 108-068 and PN 200-110 were studied by means of a computerized analysis of the intra-aortic blood pressure (BP) recorded continuously for 26 h in conscious unrestrained spontaneously hypertensive rats. Both compounds were studied at three doses (50, 100 and 200 micrograms kg-1) and each dose was administered intravenously 5 times (09 h 00 min, 14 h 00 min, 19 h 00 min, 24 h 00 min and 09 h 00 min). Baroreflex sensitivity was measured 1 h following the last injection. 2. The two compounds were found to induce rapid (3 min) and dose-dependent falls in BP. After the first administration, these decreases reached -20% and -35% for systolic BP (SBP) and diastolic BP (DBP) respectively with PY 108-068 (200 micrograms kg-1) and -25% and -45% for SBP and DBP respectively with PN 200-110 (200 micrograms kg-1). 3. The duration of the reduction in BP increased with the dose and was much longer for PN 200-110 (180 min for SBP) than for PY 108-068 (20 min for SBP). 4. A tachycardia was associated with the decrease in BP which did not differ at 200 micrograms kg-1 between PY 108-068 (+ 108 beats min-1) and PN 200-110 (+ 103 beats min-1). Baroreflex sensitivity was not significantly increased by either drug. 5. The 5 repeated injections of PY 108-068 and PN 200-110 evoked similar responses. 6. In conclusion, both compounds exhibited marked hypotensive properties. PN 200-110 appeared to be more suitable for further development since its effects were found to be greater and much longer lasting than those of PY 108-068.

Animals↗
PubMed1987

[Permeability of venous aortocoronary bypasses one year after their implantation].

For a short-term evaluation of the patency of aortocoronary bypass vein grafts, 54 consecutive patients who underwent this operation alone were examined, irrespective of their functional state, 12.4 +/- 2.1 months after surgery. Examinations included coronary arteriography, selective opacification of the graft and ventriculography. The patients were 47 men and 7 women who had coronary arteriography for stable angina pectoris (22.4%) or a recent episode of unstable angina (59.3%) or a recent myocardial infarction (18.5%). Coronary arteriography showed one-vessel (5.5%), two-vessel (27.8%) or three-vessel (42.6) disease or stenosis of the main left coronary artery (24.1%). The mean number of distal anastomoses in multiple-vessel patients was 2.6. Peri-operative mortality was 1.04%, and the proportion of peri-operative electrocardiographic signs of necrosis was 11%. At the time of control examination, 82% of the patients had few or no symptoms, and 88% were improved by at least one functional class. 79% (97/123) of distal venous anastomoses were patent. All anastomoses were patent in 59% (22/54) and all were occluded in 7% (4/54) of the patients. Localized stenosis of the graft was found in 11% and diffuse stenosis in 4% of the cases. The patency of vein grafts was higher when the distal bed was of normal size than when it was small or poorly visualized at the initial angiography (85% vs 62%, p less than 0.01), or when the diameter of the artery bypassed was greater than 1.3 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗