[Nephroprotection in young type 1 diabetic patients treated with converting enzyme inhibitor]. / Néphroprotection chez le jeune diabétique de type 1 traité par inhibiteur d'enzyme de conversion. Résultats préliminaires d'une étude prospective.

CONTEXT: Diabetic nephritis is a renal microangiopathy that represents a major cause of morbidity and mortality in diabetic patients. It is expressed either by microalbunuria, proteinuria or renal failure, depending on the stage of the diabetes. In this context, angiotensin converting enzyme inhibitors (ACEI) slow down the progression of renal damage. OBJECTIVE: To assess the nephroprotector effects of ACEI in young type 1 Moroccan diabetics with varying stages of renal damage. Methods Prospective study including 29 patients exhibiting a diabetic nephropathy and/or hypertension having been followed-up for 1 year and treated with ACEI. The following parameters were analysed on inclusion, at six months and after 1 year of treatment: systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), urinary excretion of albumin, 24-hour proteinuria, creatininemia, creatinine clearance, glycosylated haemoglobin, kalemia, total cholesterol and triglycerides. RESULTS: The mean age of our patients was of 23.6 +/- 5.5 years, the age at onset of diabetes was of 9.3 +/- 2.6 years. According to the renal damage, we determined 4 groups of patients: Group I: microalbuminuria (10 patients), Group II: proteinuria (7 patients), Group III: renal failure (6 patients), Group IV: isolated hypertension (6 patients). Study of the progression of the clinical and biological parameters, during treatment with converting enzyme inhibitors (combined with diuretics in Groups II and III) revealed: In Group I: a decrease in urinary excretion of albumin, which returned to normal in 3 cases, in Group II: a decrease in the proteinuria, which became a microalbuminuria in 4 cases, in Group III: a stabilisation of renal function concomitant to a reduction in proteinuria, in Group IV: a significant reduction in mean arterial pressure. CONCLUSION: One year of treatment with ACEI appears effective on reducing proteinuria levels and stabilising the renal function in young type 1 diabetic patients.

Hospital policy for prevention of infection after neuraxial blocks in obstetrics.

Even though most regional anesthesia textbooks and articles about infectious complications associated with central neuraxial blocks underline the necessity of surgical asepsis, none offers a clear and precise procedure. This protocol is intended to reduce variability of practices, and is felt to be stringent enough to be effective and liberal enough to be fully implemented. Any person involved with the procedure must wear a cap and a new face mask. The patient also should wear a cap. The anesthesiologist, wearing his usual operating room clothing, must wash his hands with an antiseptic soap solution, dry them on a sterile towel and wear sterile gloves. The patient's back should be disinfected at least twice (alcohol-iodine, alcoholic solution of chlorhexidine or of povidone-iodine). Disposable equipment only must be used. Drugs must be prepared contemporaneously and in a sterile manner (collar of non-sterilized ampoules cleaned with alcohol). The solution is drawn up through the filter (contained in the epidural set) but injected after filter removal. Infusion of sterile mixtures is preferable to top-ups, which require frequent disconnections that may cause hub colonization. Manipulation of the hub of the catheter must be preceded both by antiseptic hand washing and by swabbing with sterilized gauze soaked with 70% alcohol. Catheter removal requires only antiseptic hand washing in most circumstances. Wearing mask and gloves and improving skin disinfection practices are believed to be the more important parts of this protocol.

Analysis of genes involved in 6-deoxyhexose biosynthesis and transfer in Saccharopolyspora erythraea.

Glycosylation represents an attractive target for protein engineering of novel antibiotics, because specific attachment of one or more deoxysugars is required for the bioactivity of many antibiotic and antitumour polyketides. However, proper assessment of the potential of these enzymes for such combinatorial biosynthesis requires both more precise information on the enzymology of the pathways and also improved Escherichia coli-actinomycete shuttle vectors. New replicative vectors have been constructed and used to express independently the dnmU gene of Streptomyces peucetius and the eryBVII gene of Saccharopolyspora erythraea in an eryBVII deletion mutant of Sac. erythraea. Production of erythromycin A was obtained in both cases, showing that both proteins serve analogous functions in the biosynthetic pathways to dTDP-L-daunosamine and dTDP-L-mycarose, respectively. Over-expression of both proteins was also obtained in S. lividans, paving the way for protein purification and in vitro monitoring of enzyme activity. In a further set of experiments, the putative desosaminyltransferase of Sac. erythraea, EryCIII, was expressed in the picromycin producer Streptomyces sp. 20032, which also synthesises dTDP-D-desosamine. The substrate 3-alpha-mycarosylerythronolide B used for hybrid biosynthesis was found to be glycosylated to produce erythromycin D only when recombinant EryCIII was present, directly confirming the enzymatic role of EryCIII. This convenient plasmid expression system can be readily adapted to study the directed evolution of recombinant glycosyltransferases.

Residues in the ligand binding domain that confer progestin or glucocorticoid specificity and modulate the receptor transactivation capacity.

To localize regions conferring ligand binding specificity of the human glucocorticoid (hGR) and progesterone (hPR) receptors, we constructed chimeras comprising the DNA-binding domain of the yeast transcription factor GAL4, linked to the ligand binding domain of hGR or hPR. Replacement of a sequence of hGR encompassing helices H6 and H7 with the homologous sequence from hPR creates a chimeric protein GP3, which binds the progestin RU 27987 with high affinity, and results in a concomitant loss of glucocorticoid binding [dexamethasone (DEX), RU 43044]. Moreover, GP3 is not able to mediate RU 27987-induced transactivation. A detailed mutational analysis of this sequence and the study of the recently solved hPR crystal structure revealed five residues that confer progestin responsiveness to GR or modulate ligand binding and transcriptional activation. Notably, the simultaneous presence of residues Ser637 and Phe639 on GP3, lining the ligand binding pocket, is specifically involved in RU 27987 binding. The absence of residues Asp641, Gln642, and Leu647 on GP3 is accountable for the lack of glucocorticoids binding on GP3. Unlike residue 642, residues 641 and 647 are not in direct contact with the ligand and most likely act through steric-mediated interactions. The presence of Gln642 and Leu647 are determinant for transcriptional activation in response to DEX and RU 27987, respectively. DEX-dependent transactivation is further enhanced by the presence of Leu647.

Type II antagonists impair the DNA binding of steroid hormone receptors without affecting dimerization.

Two types of steroid antagonists exert their activity by different mechanisms when bound to the cognate receptor. Type I anti-progestins, such as RU486, induce DNA binding of the human progesterone receptor (hPR), while no hPR/DNA complexes were seen in gel shift assays in the presence of the type II anti-progestin ZK98,299 or RU50,331. ZK98,299-liganded hPR exerted significantly less tight nuclear binding than receptor complexes formed with RU486. Also a type II anti-glucocorticoid (RU43,044) was detected which completely abrogated DNA binding of its cognate receptor in vivo. In keeping with the existence of two different classes of anti-progestins, agonist- or RU486-induced hyperphosphorylation of the two hPR isoforms present in the T47D breast cancer cells was not induced by ZK98,299. This lack of hyperphosphorylation was, however, not the cause but most likely the consequence, of the reduced ability of the hPR/ZK98,299 complex to interact with DNA. No "mixed-ligand" heterodimers were formed in vitro between hPR isoform A bound to ZK98,299 and R5020-liganded isoform B, but nuclear co-translocation studies indicated that ZK98,299 efficiently induced hPR dimerization in vivo.

Switching agonistic, antagonistic, and mixed transcriptional responses to 11 beta-substituted progestins by mutation of the progesterone receptor.

The study of transcription activation by a series of RU486-related 11 beta-substituted progestins revealed three types of ligands: agonists, antagonists, and a novel type of compounds that exerted a mixed activity. These ligands conferred to the human progesterone receptor (hPR) only weak activation properties despite high affinity binding and, hence, acted as agonists and, at the same time, as partial antagonists of pure agonists. When the same series of ligands was tested with mutant PRs, transcriptional activation/inactivation profiles were different from those seen with the wild-type PR, since several steroids initially classified as antagonists switched to mixed responses. One compound that acted as an antagonist for the hPR was an agonist for a mutated PR in which 15 amino acids of the hormone-binding domain were replaced by the corresponding divergent residues of the chicken homolog. In analyzing a series of steroids with wild-type and mutant PRs, we observed that a phenyl group (or a phenyl derivative) in the 11 beta position of RU486-related steroids generates antagonism with hPR, but has to be bound in a critical position in the hormone-binding domain to exert its antagonistic activity. Apparently, a deviation from this positioning by mutations in the hormone-binding domain can generate mixed or even agonistic activities.

Mechanisms of antihormone action.

The mechanisms of action of two types of anti-hormones is discussed. Type I anti-hormones comprise the antiestrogen hydroxy-tamoxifen and the antiprogestin RU486, both of which promote DNA binding of the cognate receptors and, due to the activity of one of the two transcription activation functions of the estrogen and progesterone receptors, act as mixed agonist/antagonists. Evidence supporting that ICI 164,384 is also a member of the same group is presented. Type II antagonists impair DNA binding of the corresponding receptor in vitro and, in some cases, also in vivo. Ligand-mapping, an approach to identify the site of interaction of a steroid substitution within the hormone-binding domain of the receptor has been used to identify the 11 beta-pocket of the progesterone receptor and revealed that a single amino acid is responsible for the differential antagonistic effect of RU486 in man, chicken and hamster.

A single amino acid that determines the sensitivity of progesterone receptors to RU486.

The progesterone analog RU486, an abortifacient, inhibits the action of progestins in humans but not in chickens or hamsters. Substitution of cysteine at position 575 by glycine in the hormone binding domain (HBD) of the chicken progesterone receptor (cPR) generated a cPR that binds RU486 and whose activity is antagonized by that compound. In fact, all receptors that bind RU486 have a glycine at the corresponding position. The hamster PR, like cPR, has a cysteine. Only glycine--not methionine or leucine--at position 575 allowed binding of RU486 to cPR. Substitution of this glycine by cysteine in the human PR (hPR) abrogated binding of RU486 but not that of an agonist. The corresponding mutation in the human glucocorticoid receptor resulted in a loss of binding of both dexamethasone and RU486. Examination of a series of 11 beta-substituted steroids showed that antagonism is not an intrinsic property of an antihormone, because one hPR antagonist acted as an agonist for a mutated hPR. The positioning of an aromatic 11 beta-substitution in the PR HBD appears to be critical for generating agonistic or antagonistic activity.

[Cerebral ischemia and severe digestive manifestations during rheumatoid purpura]. / Ischémie cérébrale et manifestations digestives sévères au cours d'un purpura rhumatoïde.

A 14-year-old male patient with Schönlein-Henoch vasculitis developed neurologic manifestations including cortical blindness, seizures and CT scan evidence of occipital ischemia. These manifestations occurred concomitantly with severe bleeding from a duodenal ulcer seen at endoscopy. Corticosteroid therapy was initially rejected then finally given because of the severity of neurologic involvement. Both neurologic and digestive manifestations improved rapidly. A control digestive endoscopy performed 30 days later was normal.

[Infantile visceral leishmaniasis in Morocco. A review of 67 cases managed at the Rabat Hospital for children (1979-1988)]. / Leishmaniose viscérale infantile au maroc. Expérience de l'Hôpital d'Enfants de Rabat à propos de soixante-sept cas (1979-1988).

Sixty-seven cases of visceral leishmaniasis managed at the Rabat Hospital for Children from 1979 through 1988 were studied retrospectively. Mode of onset and outcome were analyzed. Clinical manifestations included enlargement of the spleen (60 cases), fever (45 cases), enlargement of the liver (38 cases), and weight loss (53 cases). Six patients had misleading onset manifestations including one case each of pigmentary lithiasis, severe marasmus without enlargement of the spleen, nephrotic syndrome, evidence of portal hypertension, jaundice, and an abdominal mass. Diagnosis was established by the bone marrow study (positive in 58 of 66 patients) or by indirect immunofluorescence (positive in 21 of 24 patients, including 6 with a negative bone marrow study). In one patient, the parasite was recovered from a jejunal biopsy specimen. Drugs used included N-methyl-glucamine in 86 cases, pentamidine in 26 cases, and sodium gluconate stibio in one case. Complete recovery was achieved in 24 patients. Seven patients failed to respond to therapy. There were 8 deaths, including 4 prior to initiation of therapy; among these four deaths, three were due to acute anemia. Another patient died after leaving the hospital despite the physician's advice to the contrary. The 3 remaining deaths were caused by toxicity of the drugs used. Thirty-one patients were lost to follow-up after initial improvement. The severity of this disease and cost of management make earlier diagnosis and faultless management imperative.