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Biomedical subjects

J Rosa

Publications and source records attributed to J Rosa.

At least 19 recordsLinked to original sources
PubMed2000

The cytotoxic effect of wastewater from the phosphoric gypsum depot on common oak (Quercus robur L.) and shallot (Allium cepa var. ascalonicum).

The effect of wastewater from a phosphoric gypsum depot on common oak, Quercus robur L., at cytogenetical level was studied. Allium-test was used as a control. The treatment of common oak seedlings with wastewater under laboratory conditions caused mitodepressive effect. Chromosome aberrations and mitotic irregularities were found. Cytogenetic analysis of common oak seedlings grown from acorns collected near the depot did not show changes in mitotic activity in comparison to control but the number of aberrations was higher than in control. In comparison to Alliumtest common oak was found to be more tolerant to wastewater from the phosphoric gypsum depot.

Allium↗
PubMed2000

[Genetics and the precautionary principle].

It is very important to follow the Precautionary Principles with regard to genetics because of its fast development and of its impact in the public imaginer. In that regard gene grafts, OGM or recombinant drugs are pre-eminently be suspected to transmit human or animal viruses and/or to induce severe allergies. Pharmaceutical Industry has conducted large reflexions on such problems and are using drastic rules to prevent them. By contrast, academic research laboratories are handicapped by the problem of fund seeking. At the genetic disease level and mainly because the fast development of Predictive Medicine, patient and family councelling requires a great lot of reflexion and carefulness. Memorization of the presence of abnormal genes in the history of families also constitutes an important problem. We believe that, to be in accordance with the Precautionary Principles, an important work of formation and information is required.

Drug Industry↗
PubMed1999

Short chain fatty acids are effective in short-term treatment of chronic radiation proctitis: randomized, double-blind, controlled trial.

PURPOSE: Short chain fatty acids are the main energy source of colonocytes and their use may be impaired in chronic radiation proctitis. The aim of the present study was to evaluate the therapeutic effect of short chain fatty acid enemas in patients with chronic radiation proctitis. METHODS: A prospective, randomized, double-blind trial comparing short chain fatty acid enemas with placebo was conducted in 19 patients with chronic radiation proctitis. Short chain fatty acid enemas contained 60 mM sodium acetate, 30 mM sodium propionate, and 40 mM sodium butyrate. The treatment period lasted five weeks and patients were followed up for six months. RESULTS: On admission, both groups were similar regarding all parameters evaluated. After five weeks short chain fatty acid-treated patients showed a significant decrease in the number of days with rectal bleeding from the previous week (4.4+/-1.8 to 1.4+/-2.2; P = 0.001) and an improvement of endoscopic score (4.8+/-1.4 to 2.2+/-1.2; P = 0.001). Hemoglobin values were also significantly higher in short chain fatty acid-treated patients (13.1+/-0.9 g/dl vs. 10.7+/-2.1 g/dl; P = 0.02). Mucosal DNA and protein concentrations decreased in both groups but significantly so only in placebo-treated patients (P = 0.05). Changes in histologic parameters were not significant in either group. Although short chain fatty acid-treated patients did not get worse in the next six months, placebo-treated ones gradually improved, and at the end of six months, differences between the two groups were no longer observed. CONCLUSIONS: Short chain fatty acid enemas can accelerate the process of healing in chronic radiation proctitis, but treatment has to be continuous if a complete and sustained clinical, endoscopic, and histologic response is to be obtained.

Chronic Disease↗
PubMed1998

[Plastic and reconstructive surgery in oncology].

The authors are members of the surgical staff of a central hospital specialized in the treatment of cancer (Portuguese Institute of Oncology-Francisco Gentil, Lisboa). They present their experience as plastic and reconstructive surgeons, mostly in the use of current reconstructive possibilities, after excision surgery or in a later phase. The aim is to offer the best quality available, which is evaluated by morbidity, mortality and quality of life. Most of the patients are subjected to different series of oncologic therapy, which is submitted to a multidisciplinary decision.

Breast Neoplasms↗
PubMed1997

Critical role of human bisphosphoglycerate mutase Cys22 in the phosphatase activator-binding site.

The enzymatic activities catalyzed by bisphosphoglycerate mutase (BPGM, EC 5.4.2.4) have been shown to occur at a unique active site, with distinct binding sites for diphosphoglycerates and monophosphoglycerates. The physiological phosphatase activator (2-phosphoglycolate) binds to BPGM at an undetermined site. BPGM variants were constructed by site-directed mutagenesis of three amino acid residues in the active site to identify residues specifically involved in the binding of the monophosphoglycerates and 2-phosphoglycolate. Substitution of Cys22 by functionally conservative residues, Thr or Ser, caused a great decrease in 2-phosphoglycolate-stimulated phosphatase activity and in the Ka value of the activator, whereas it caused no change in other catalytic activities or in the Km values of 2,3-diphosphoglycerate (2,3-DPG) and glycerate 3-phosphate (3-PG, EC 1.1.1.12), indicating that Cys22 is specifically involved either directly or indirectly in 2-phosphoglycolate binding. Kinetic experiments showed that the Ka of the cofactor and the Km of 3-PG were affected by the substitution of Ser23 indicating that this residue is necessary for the fixation of both 3-PG and 2-phosphoglycolate. The R89K variant has previously been shown to have a modified Km value for monophosphoglycerates, however, its affinity for 2-phosphoglycolate is unaltered, suggesting that Arg89 is specifically involved in monophosphoglycerates binding. CD spectroscopic studies of substrates and cofactor binding showed that 2,3-DPG induced structural modifications of normal and mutated enzymes which could be due to protein phosphorylation. Addition of 2-phosphoglycolate to phosphorylated proteins with normal affinity for the cofactor produced spectra with the same characteristics as unphosphorylated species. In summary, monophosphoglycerates and 2-phosphoglycolate have partially distinct binding sites in human BPGM. The specific implication of the Cys22 residue in 2-phosphoglycolate binding is of great significance in the design of analogs of therapeutic benefit.

Binding Sites↗
PubMed1997

Endoscopic screening for dysplasia and mucosal aneuploidy in adolescents and young adults with childhood onset colitis.

OBJECTIVES: In adults, the premalignant nature of ulcerative colitis (UC) has long been accepted. Currently there is increasing concern that Crohn's disease (CD) may be equally premalignant. As a consequence, most adults with long-standing UC and many with chronic CD are enrolled in ongoing endoscopic cancer surveillance programs. In contrast, the risk of colonic cancer in adolescents and young adults with either form of colitis is less well recognized, and the need for dysplasia and cancer screening in this population has not been systematically evaluated. We therefore report the prospective results of colonoscopic cancer screening in such a young population. METHODS: Thirty-five adolescents and young adults with long-standing colitis (18 UC, 17 CD; 21 +/- 3 yr old, 11 +/- 3 yr colitis duration) underwent colonoscopic cancer screening. All had multiple biopsies for flow cytometry and light microscopy. RESULTS: Seven subjects had aneuploidy (3/18 UC, 4/17 CD). Of these seven, only two had dysplasia [one high grade (UC), one low grade (CD)]. One additional subject had indefinite dysplasia with normal flow cytometry. The remaining 27 subjects had both normal flow cytometry and light microscopy. Five of the seven aneuploid subjects underwent surgery within 1 yr of screening. Four, including both subjects with dysplasia, had no evidence of colon cancer at surgery. However, a 24-yr-old female with a 14-yr history of UC and no evidence of dysplasia or cancer at screening had a Dukes C adenocarcinoma. CONCLUSIONS: Adolescents and young adults with childhood onset UC or CD are at risk for aneuploidy, dysplasia, and colon cancer. Aneuploidy can be evident 10 yr after the onset of colitis and in patients as young as 16 yr of age. Therefore, the risk for colon cancer in patients with childhood onset colitis must be based on the duration of the illness, not on their chronological age. Incorporation of flow cytometry into an endoscopic screening protocol appears to enhance the ability to identify individuals at highest risk for colon cancer.

Adolescent↗
PubMed1995

Highly destructive perianal disease in children with Crohn's disease.

The perianal complications of Crohn's disease (CD) seen in children and adolescents include skin tags, anal fissures, fistulae, and abscesses. While these lesions are often chronic and variably responsive to medical therapy, only rarely are they severely destructive. In this report, we characterize the frequency, severity, and clinical course of a highly destructive form of perianal disease (HDPD) that we have noted in a number of children and adolescents with Crohn's disease. A database containing records from 350 children with inflammatory bowel disease was reviewed to identify all children with CD treated between 1970 and 1993. For each, the occurrence or absence of significant perianal pathology, including fistula, abscess, and HDPD, was determined. Pertinent clinical details were recorded for all patients. In addition, the clinical characteristics of those children with HDPD were compiled, and the courses of those with HDPD characterized. A search of the database identified 230 children and adolescents with CD followed for a total of 1,518 patient years. Sixty-seven of these patients (29% of the CD population) had significant perianal pathology. This included 6 with HDPD, 8 with complicated fistulae [rectourethroperineal (1), rectovaginal (1), rectolabial (2), and multiple communicating perineal (4)], and 53 with simple perianal fistulae or abscesses. All six with HDPD had deeply destructive perineal ulcerations, marked undermining of the perineal and perirectal tissues, and copious exudate, and often there was a deeply cleaved or fileted perineum on separating the buttocks. Two children with HDPD had fecal incontinence.

Abscess↗
PubMed1995

Geographic distribution of 119 alleles of the alpha and beta globin genes detected in 432 French Caucasian carriers of haemoglobin variant.

The French population is the result of mixing of different peoples including the Celts, Saxons, Germans, Italians and Hispanics. Between 1981 and 1993 patients were selected during investigations in France for haematological disorders associated or otherwise with the presence of a haemoglobin (Hb) variant. Further carriers of abnormal Hb were identified by HPLC measurement of glycated Hb in diabetics and by neonatal screening. Four-hundred and thirty-two subjects were found to be heterozygous for one of the 119 different alpha and the beta gene alleles encountered. These variants were characterised by a combination of 6 electrophoretic methods and in some cases by protein structure determinations. Some mutants reflected the population movements in and into France. A few mutants are frequently described in the French Caucasian population: Hb Lepore Boston, Hb D Punjab, whereas others appear to be anthropological markers. Hb Winnipeg has only been found in the West of France (Normandy); Hb J Baltimore is mainly found in French subjects of Spanish origin. Several cases of sporadic and previously undescribed mutations of Hb were identified. The last immigration waves from Africa and Asia appear to have contributed to the evolution of the pattern of haemoglobinopathies in the French population (Hb S, Hb O Arab or Hb C).

Alleles↗
PubMed1994

A recombinant bisphosphoglycerate mutase variant with acid phosphatase homology degrades 2,3-diphosphoglycerate.

To date no definite and undisputed treatment has been found for sickle cell anemia, which is characterized by polymerization of a deoxygenated hemoglobin mutant (HbS) giving rise to deformed erythrocytes and vasoocclusive complications. Since the erythrocyte glycerate 2,3-bisphosphate (2,3-DPG) has been shown to facilitate this polymerization, one therapeutic approach would be to decrease the intraerythrocytic level of 2,3-DPG by increasing the phosphatase activity of the bisphosphoglycerate mutase (BPGM; 3-phospho-D-glycerate 1,2-phosphomutase, EC 5.4.2.4). For this purpose, we have investigated the role of Gly-13, which is located in the active site sequence Arg9-His10-Gly11-Glu12-Gly13 in human BPGM. This sequence is similar to the Arg-His-Gly-Xaa-Arg* sequence of the distantly related acid phosphatases, which catalyze as BPGM similar phosphoryl transfers but to a greater extent. We hypothesized that the conserved Arg* residue in acid phosphatase sequences facilitates the phosphoryl transfer. Consequently, in human BPGM, we replaced by site-directed mutagenesis the corresponding amino acid residue Gly13 with an Arg or a Lys. In another experiment, we replaced Gly13 with Ser, the amino acid present at the corresponding position of the homologous yeast phosphoglycerate mutase (D-phosphoglycerate 2,3-phosphomutase, EC 5.4.2.1). Mutation of Gly13 to Ser did not modify the synthase activity, whereas the mutase and the phosphatase were 2-fold increased or decreased, respectively. However, replacing Gly13 with Arg enhanced phosphatase activity 28.6-fold, whereas synthase and mutase activities were 10-fold decreased. The presence of a Lys in position 13 gave rise to a smaller increase in phosphatase activity (6.5-fold) but an identical decrease in synthase and mutase activities. Taken together these results support the hypothesis that a positively charged amino acid residue in position 13, especially Arg, greatly activates the phosphoryl transfer to water. These results also provide elements for locating the conserved Arg* residue in the active site of acid phosphatases and facilitating the phosphoryl transfer. The implications for genetic therapy of sickle cell disease are discussed.

2,3-Diphosphoglycerate↗
PubMed1994

Hemoglobin variants in North Africa.

The populations of Morocco, Algeria, and Tunisia are composed of different ethnic groups including Arabs, Berbers, Sub-Saharan Africans, Europeans, and Turks. Between 1981 and 1991, we studied more than 3,000 individuals from these North African countries. One-hundred and eighty-one carried one (or more) unusual hemoglobin variant(s) other than Hb S and Hb C which are the most frequent variants in these countries. Each of these 181 individuals was heterozygous for at least one of the 49 abnormal alpha or beta alleles identified by electrophoretic and/or structural studies, and some homozygotes were detected. A few mutants are common in North Africa: Hb O-Arab, Hb D-Punjab and Hb G-Philadelphia. Other mutants encountered in European or African populations are found in relatively few North African families. The observed polymorphisms in the populations of North Africa probably result largely from their complex ethnic origins.

Algeria↗
PubMed1993

Reducing unnecessary laboratory use with new test request form: example of tumour markers.

To limit the ordering of serum tumour marker tests that are clinically irrelevant, we designed a new request form. This is a matrix of boxes, rows being individual markers and columns body organs. The box at the intersection of line and column is colour-coded to indicate whether the test is appropriate or not. These ratings were allocated on the basis of published data and local consensus. This new form replaced the form in use at our hospital at the beginning of 1992, and resulted in a 25% decrease in the ordering of tumour markers. Adapting the design of the test request form is a low-cost intervention that combines both economic and clinical requirements in reducing the prescription of tests that are useless in a given clinical situation.

Acid Phosphatase↗
PubMed1993

Amino acid residues involved in the catalytic site of human erythrocyte bisphosphoglycerate mutase. Functional consequences of substitutions of His10, His187 and Arg89.

Human bisphosphoglycerate mutase (GriP2 mutase) is a trifunctional enzyme which synthesizes and degrades GriP2 in red cells. Among the amino acid residues involved in its active site there are two conserved histidine residues, His10 which is phosphorylated during the catalytic process and His187 for which only speculative data have been made about the potential role during the reactions. Another amino acid residue, Arg89, had not been described as part of this active site but we have recently shown that a natural mutant Arg89-->Cys was highly thermolabile and showed severe perturbations of its enzymatic properties. To understand better the exact role of these residues, replacements of His10 by Gly (H10G) or Asp (H10D), His187 by Asn (H187N), Tyr (H187Y) or Asp (H187D) and Arg89 by Cys (R89C), Ser (R89S), Gly (R89G) or Lys (R89K) were performed by site-directed mutagenesis. The results obtained in this report show that replacement of the His10 residue completely abolished the enzymatic activities. Concerning the His187 residue, our results afford arguments that it plays an essential role in the three catalytic activities. Indeed all these activities are abolished in the two H187Y and H187D variants, whereas they are detectable though strongly diminished, for the H187N variant. In addition mutations at His187 could be distinguishable from those at His10 since the former resulted in a thermolabile enzyme, whereas no significant change in heat stability was observed for the latter. It is noteworthy that the H187N variant is protected against thermal instability by glycerate 2,3-bisphosphate (GriP2). Concerning the Arg89 mutants, R89C, R89S and R89G, the three variants showed characteristics identical to those found in the natural R89C mutant, i.e. loss of 99% of synthase activity, consistent decrease of mutase and 2-phosphoglycolate-stimulated phosphatase activities whereas the unstimulated phosphatase activity was normal. Moreover these mutants were unstable at 55 degrees C but GriP2 was able to protect them against thermal instability. In contrast, the R89K mutant was stable at 55 degrees C. Its synthase and unstimulated phosphatase activities were normal but its mutase and 2-phosphoglycolate-stimulated phosphatase activities were decreased. In addition, Km values for monophosphoglycerates were increased (3.2-fold) in the synthase but normal in mutase activities, whereas Km values for GriP2 were normal in mutase and phosphatase activities.(ABSTRACT TRUNCATED AT 400 WORDS)

Arginine↗
PubMed1993

Unstable alpha-chain hemoglobin variants with factitious beta-thalassemia biosynthetic ratio: Hb Questembert (alpha 131[H14]Ser-->Pro) and Hb Caen (alpha 132[H15]Val-->Gly).

Hb Questembert [alpha 131(H14)Ser-->Pro] was found in several members of a French family suffering from congenital Heinz body anemia. The unstable hemoglobin was expressed in the peripheral red blood cells at a very low level. Globin biosynthetic studies revealed a high specific activity of the abnormal chain and an alpha-/beta-labeling ratio similar to that of beta-thalassemia trait. Hb Caen [alpha 132(H15) Val-->Gly] is another unstable variant with the same globin biosynthesis abnormality. In both cases the structural modification is localized at the end of the H helix, a region encoded by the third exon. The mechanism for the unbalanced globin synthesis is not yet clear. It may be related 1) to a defect in chain assembly, 2) to an increased rate of degradation of the variant chain followed by the release of unlabeled beta-chains from the abnormal hemoglobin, thus leading to an apparent suppression of beta-chain synthesis, or 3) to a modified stability of the abnormal alpha-globin mRNA.

Adult↗
PubMed1993

Growth failure in pediatric inflammatory bowel disease.

To assess whether children with inflammatory bowel disease (IBD) develop permanent impairment of linear growth, we analyzed records from 48 young adults who had IBD during childhood or early adolescence (Tanner I-III; 11.8 +/- 2.4 years old at diagnosis). All were fully grown (Tanner V; 21.1 +/- 3.0 years) at last examination. Adult heights were predicted from data obtained at or shortly after the diagnosis of IBD by three methods: height for age percentile, the Bailey-Pinneau (BP), and Roche-Wainer-Thissen (RWT) methods. Predicted adult heights were then compared with the actual ultimate height of each subject. Permanent growth failure occurred in 19-35% of subjects, depending upon the method used to assess growth. Overall, 31% (15 of 48) of the subjects had deficits of adult height identified by two or more methods, including 14 of 38 (37%) of those with Crohn's disease but only one of 10 with ulcerative colitis. Age at diagnosis of IBD, age at last examination, age at cessation of linear growth, and site of IBD did not differ between impaired and normal growth groups. Duration of corticosteroid use was longer (p < 0.05) in growth-impaired subjects. In addition, although 60% of all subjects had periods of poor growth that put them in height-for-age percentiles two or more major growth channels below previous percentiles, only 19% remained at these levels upon achieving their final adult heights. Permanent impairment of linear growth leading to clinically meaningful deficits of ultimate adult height is common in patients with IBD in childhood or early adolescence. New therapeutic approaches are needed to address this problem.

Adolescent↗