Isolation,purification and 13C-and 1H-n.m.r. assignments of peptide [1–24] of human serum albumin

Isolation, purification and 360 MHz ¹H- and ¹³C-n.m.r. spectra of the residue corresponding to the NH₂-terminal peptide fragment [1–24] of human serum albumin are reported. The various resonances have been assigned to individual amino acid residues and their spatial microenvironment has been determined in a straightforward manner on the basis of (i) pH dependent chemical shifts; (ii) combined use of multiple and selective proton-decoupled ¹H- and ¹³C-n.m.r. spectra; (iii) the characteristic pK values exhibited by protons adjacent to sites of ionization in the molecule; and (iv) comparison of the spectra with the NH₂-terminal tripeptide segment of human albumin. The pK values of different ionizable groups all fall in the normal range expected for each titrating sites and support a model of peptide fragment [1–24] in which there is no special structure-forming strong associations. These results are in agreement with those obtained by CD spectroscopy.     

IMMUNOHISTOCHEMICAL DETECTION OF p53 PROTEIN OVEREXPRESSION VERSUS GENE SEQUENCING IN URINARY BLADDER CARCINOMAS

PURPOSE: Mutations of p53 tumor suppressor gene and nuclear accumulation of p53 protein are common in bladder tumors. The prognostic significance of p53 alterations in bladder tumors has not been established. The aim of the present study was to evaluate an immunohistochemical (IHC) method for the routine determination of p53 protein overexpression in human bladder tumors and to determine the relation between nuclear accumulation of p53 with the traditional prognostic indicators and patient survival. MATERIALS AND METHODS: 104 transitional cell carcinomas of the bladder were analyzed simultaneously by immunohistochemistry for p53 protein overexpression and direct DNA sequencing for p53 gene mutations. RESULTS: The overexpression of p53 protein was reported in 30.8% of the cases and mutations of p53 gene in 23.0%. A significant association was observed between p53 alterations established either by IHC or direct DNA sequencing and stage (p<0.0001), grade (p<0.001), vascular invasion (p = 0.0005), DNA ploidy (p = 0.0002) and carcinoma in situ (p<0.0001). The correlation between the p53 gene mutations and p53 nuclear reactivity as detected by IHC was highly significant (p<0.0001). Univariate statistical analysis showed that the expression of p53 was significantly correlated to poor prognosis (p<0.0001). However, in multivariate analysis, only stage was significantly correlated to prognosis (p<0.0001). CONCLUSIONS: The IHC method was highly sensitive and specific and simple to apply for the routine examination of p53 overexpression in bladder tumors. However, overexpression of p53 as determined immunohistochemically, does not appear to have a better predictive prognostic value than stage in bladder tumors.     

Vitamin K-dependent carboxylase

The conformational analysis of four glutamic acid analogues containing a cyclopentyl or cyclohexyl ring, substituted in position 1 by a Boc-protected amino group and a methyl ester group and in position 3 by a free carboxylate group (6–9), has been carried out in an aqueous environment, by ¹H and ¹³C NMR spectroscopy, and molecular dynamics (MD). These compounds have been shown to be weak competitive inhibitors (K_i? 20–65 mM) of the vitamin K-dependent carboxylation of Boc-Glu-OMe in rat liver microsomes independently of their ring size and stereochemical features. However, the cyclic trans isomers have been found more active than the cis ones and Boc-trans-C5-OMe (9) is the most potent inhibitor in the series (cis and trans isomers are defined by the relative arrangement of the carboxyl functions). Such cyclic glutamyl derivatives may provide valuable informations on the preferred bioactive conformations of synthetic glutamyl substrates at the active site of the carboxylase. In aqueous solution, the Boc-cis- and trans-C6 esters exhibit chair conformations with exclusively equatorial and axial substituent positions, while the Boc-cis- and trans-C5 compounds may display envelope E or ‘twist’ T conformations with the substituents in the following positions. equatorial, axial and isoclinal. For each compound, the conformations resulting from NMR and MD data were analyzed and classified according to the dihedral angles %1 and %2, the distances of functional groups, and the spatial charge distribution involving the free carboxyl group. A reduced number of conformational families were found to be in qualitative agreement with NMR and MD data. These results are discussed in relation with the carboxylase inhibitory activity of the analogues, and a spatial disposition of the glutamyl side chain that could be recognized by the carboxylase is deduced. © Munksgaard 1997.     

Unilateral Nevoid Telangiectasia and chronic Liver Disease

Unilateral nevoid telangiectasia was observed on the back of the left hand and wrist in a 19-year old man with chronic liver disease and portal hypertension. Moreover, abnormalities of the elastic fibers of the skin were found. Examination of the liver biopsy showed extensive portal fibrosis with many dilated blood vessels. No usual cause of juvenile cirrhosis was detected. In the comment, the authors suggest that unilateral nevoid telangiectasia and liver disease could be manifestations of a disease involving skin and liver vessels, as in hereditary hemorrhagic telangiectasia.     

CORTICOTROPHIN-LIKE INTERMEDIARY LOBE PEPTIDE AS A MARKER OF ALTERNATE PRO-OPIOMELANOCORTIN PROCESSING IN ACTH-PRODUCING NON-PITUITARY TUMOURS

In order to evaluate which of human (h) corticotrophin-like intermediary lobe peptide (CLIP) or h beta-melanocyte stimulating hormone5-22 (h beta MSH5-22) was the better marker of alternate pro-opiomelanocortin (POMC) processing, both peptides were simultaneously sought in the same tissue extracts from a normal human pituitary, six corticotrophic adenomas, and four non-pituitary tumours responsible for an ectopic ACTH syndrome. Human CLIP was detected using a combination of gel exclusion chromatography and two different radioimmunoassays (RIAs): a mid-ACTH RIA which recognized ACTH but not CLIP, and a COOH-ACTH RIA which recognized both molecules. Human beta MSH5-22 had been measured previously. Neither hCLIP nor h beta MSH5-22 were detected in the normal or tumoural pituitaries. The four non-pituitary tumours, in contrast, contained both peptides; the hCLIP and h beta MSH5-22 ratios (CLIP/CLIP + ACTH and h beta MSH5-22/h beta MSH5-22 + h gamma LPH) ranged from 40 to 94% and from 24 to 46%, respectively. In a given tissue the hCLIP ratio was always higher than the h beta MSH5-22 ratio. hCLIP is therefore the better marker of alternate POMC processing.     

Synthesis of pseudo-peptide analogues of the C-terminal tetra-peptide of gastrin and evaluation of their biological activity on acid secretion

The syntheses of pseudo-tetrapeptides Boc-Trp-ψ(CH₂-NH)-Met-Asp-Phe-NH₂ 21 and Boc-Trp-Met-ψ(CH₂-NH)-Asp-Phe-NH₂ 20, representing the C-terminal tetrapeptide sequence of gastrin, in which amide bonds were replaced by CH₂-NH bond, are described, as well as the syntheses of pseudo-peptide analogues Boc-Trp-ψ(CH₂ -NH)-Nle-Asp-Phe-NH₂ 16, Boc-Trp-Nle-ψ(CH₂-NH)-Asp-Phe-NH₂ 11, and Boc-Trp-Nle-Asp-ψ(CH₂-NH)-Phe-NH₂ 5, in which the methionyl residue was replaced by a norleucyl residue. Pseudo-peptides 16 and 21, in which the amide bond between Trp and Met (or Nle) was substituted by a CH₂-NH) bond, stimulated gastric acid secretion in the rat in vivo. Pseudo-peptides 11,16,20 and 21, where the amide bond between Met (or Nle) and Asp was replaced by a CH₂-NH bond, did not exhibit any activity on acid secretion in the rat in vivo but were potent inhibitors of pentagastrin-incluced acid secretion. Peptides 11, 16, 20 and 21 all recognize the gastrin receptor on a mucosal cell preparation. Pseudo-peptide 5, in which the amide bond between Asp and Phe was replaced by a CH₂-NH bond, was a less potent inhibitor of pentagastin-induced acid secretion and had a weaker affinity than the other pseudo-peptides.     

Should medicines be distributed by health services or pharmacies? A preliminary evaluation of the Boulgou project in Burkina Faso

Drug distribution by pharmacies is fraught with difficultiesin Africa. These include: improper use of medication by healthprofessionals; by-passing health services leading to irrationalserf-medication; the inevitable fee-for-service payment scheme;and finally inadequate management. In this article, a healthcentre in Burkina Faso is evaluated for these problems usingquantitative and qualitative methods. The reality of the problemsjustifies consideration of an alternative drug distributionarrangement, perhaps via the health services.     

The Role of the Kidney in the Production of the Erythropoietic Factor

The role of the kidney in production of erythropoietin was investigated.Dogs were made anemic by phlebotomy and were then subjected to bilateralnephrectomy, ureter ligation or ureter section. Erythropoietic stimulating activity in the dog plasma was judged by measuring the incorporation of Fe⁵⁹into the red cells of starved rats. No erythropoietic activity could be found inthe dog plasma 24 and 48 hours after nephrectomy, but erythropoietic activitywas found after ligation of the ureters.

Submitted on July 19, 1960 Accepted on September 14, 1960     

Comparison of antihypertensive efficacy and perinatal safety of labetalol and methyldopa in the treatment of hypertension in pregnancy: a randomized controlled trial

Summary. Labetalol was compared with methyldopa in a randomized controlled trial involving 176 pregnant women with mild to moderate hypertension. Diastolic blood pressure below 86 mmHg was obtained in a similar proportion of women given labetalol or methyldopa. Intrauterine death occurred in four women treated with methyldopa, and the one neonatal death on day 1 occurred in the labetalol group. The average birthweight and the proportion of preterm or small-for-gestational-age babies were similar in both groups. Heart rate, blood pressure, blood glucose, respiratory rate, and Silverman score of the babies did not differ between the two treatment groups, whether the comparison was made for all the infants, or only for those that were preterm or small-for-gestational-age. These data indicate that maternal betablockade with labetalol is as safe as methyldopa for the fetus and the newborn.