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Biomedical subjects

M Martell

Publications and source records attributed to M Martell.

At least 19 recordsLinked to original sources
PubMed1996

Transmission of hepatitis C virus by a cardiac surgeon.

BACKGROUND: In the course of a study conducted in 1992 through 1994 of the efficacy of screening blood donors for antibodies to hepatitis C virus (HCV), we found that two patients had acquired hepatitis C after cardiac surgery, with the transmission apparently unrelated to blood transfusions. Because their surgeon had chronic hepatitis C, we sought to determine whether he was transmitting the virus to his patients. METHODS: Of 222 of the surgeon's patients who participated in studies of post-transfusion hepatitis between 1988 and 1994, 6 contracted postoperative hepatitis C, despite the use of only seronegative blood for transfusions. All six patients had undergone valve-replacement surgery. Analyses were performed to compare nucleotide sequences encompassing the hypervariable region at the junction between the coding regions for envelope glycoproteins E1 and E2 in the surgeon, the patients, and 10 controls infected with the same HCV genotype. RESULTS: The surgeon and five of the six patients with hepatitis C unrelated to transfusion were infected with HCV genotype 3; the sixth patient had genotype 1 and was considered to have been infected from another source. Thirteen other patients of the surgeon had transfusion-associated hepatitis C and were also infected with genotype 1. The average net genetic distance between the sequences from the five patients with HCV genotype 3 and those from the surgeon was 2.1 percent (range, 1.1 to 2.5 percent; P < 0.001), as compared with an average distance of 7.6 percent (range, 6.1 to 8.3 percent) between the sequences from the patients and those from the controls. The results of phylogenetic-tree analysis indicated a common epidemiologic origin of the viruses from the surgeon and the five patients. CONCLUSIONS: Our findings provide evidence that a cardiac surgeon with chronic hepatitis C may have transmitted HCV to five of his patients during open-heart surgery.

Adult↗
PubMed1994

Dynamic behavior of hepatitis C virus quasispecies in patients undergoing orthotopic liver transplantation.

We have studied the distribution of viral sequences from the 5' noncoding region and from a fragment of the E2/NS2 region of the hepatitis C virus (HCV) genome in samples obtained before and after liver transplantation in two patients with HCV cirrhosis. The population of viral sequences in both regions were established by sequencing cloned PCR products. In both cases, the complexity of the viral quasispecies decreased after transplantation, although the consensus nucleotide and amino acid sequences remained unchanged. It is suggested that both positive and negative selection and random sampling events contribute substantially in shaping the genetic composition of HCV quasispecies and that recurrence of HCV infection may occur under equilibrium conditions.

Amino Acid Sequence↗
PubMed1994

Repeated direct fetal intravascular high-dose immunoglobulin therapy for the treatment of Rh hemolytic disease.

Recently, administration of high-dose intravenous immunoglobulin (HDivIG) either to the mother or the neonate has been proposed in an effort to prevent progressive hemolysis in Rh(D) perinatal disease, but no cases have been published with direct fetal HDivIG administration. We report a case in which HDivIG was repeatedly administered by cordocentesis to a fetus affected by Rh(D) disease from 28 to 36 weeks gestation, at doses of approximately 450 mg/kg. The fetus required no transfusions, and the neonatal evolution was satisfactory. The treatment, performed at three weeks intervals, seemed to be useful in preventing fetal hemolysis. No fetal complications were present. Recurrent administration of HDivIG therapy to the fetus in cases of severe Rh(D) disease, appears to be feasible and free of serious complications to the fetus or the mother.

Adult↗
PubMed1993

Suction patterns in preterm infants.

The suction pattern for breast and bottle feeding in two groups of preterm infants is described. The time elapsed between birth and the moment of suction was longer in preterm neonates born at lower gestational ages for both groups studied, breast and bottle fed (figure 1). The evolution of suckling in breastfeeding was analyzed in a composite study (longitudinal and transverse) in a group of 16 neonates starting from 32 weeks of gestation. The velocity of milk extraction during suckling varied with gestational age. It was uniform at lower gestational ages, then it became faster in the first minutes and at the 36th week, it was very similar to that of mature neonates (figure 2 and table I). The evaluation of bottle feeding was performed in a transverse study in 46 preterm neonates which had been exclusively bottle fed during 1 or 2 weeks. All of them had previously been fed using an orogastric tube. Nourishing time was shorter than in breastfeeding; the average duration was 3.7 minutes (table II). The greatest volume was ingested in the first minute, 40% (range between 44 and 25%) (figure 3). The frequency of suction did not change the duration of feeding, but it was found that the efficiency of suction (number of suctions to ingest 1 cc) was significantly lower in the first minute (Anova, p < 0.05) (figure 4).

Bottle Feeding↗
PubMed1992

Hepatitis C virus (HCV) circulates as a population of different but closely related genomes: quasispecies nature of HCV genome distribution.

Sequencing of multiple recombinant clones generated from polymerase chain reaction-amplified products demonstrated that the degree of heterogeneity of two well-conserved regions of the hepatitis C virus (HCV) genome within individual plasma samples from a single patient was consistent with a quasispecies structure of HCV genomic RNA. About half of circulating RNA molecules were identical, while the remaining consisted of a spectrum of mutants differing from each other in one to four nucleotides. Mutant sequence diversity ranged from silent mutations to appearance of in-frame stop codons and included both conservative and nonconservative amino acid substitutions. From the relative proportion of essentially defective sequences, we estimated that most circulating particles should contain defective genomes. These observations might have important implications in the physiopathology of HCV infection and underline the need for a population-based approach when one is analyzing HCV genomes.

Amino Acid Sequence↗
PubMed1990

Heterogeneity of HLA genetic factors in IDDM susceptibility.

The association of certain HLA-D alleles with insulin-dependent diabetes mellitus (IDDM) is well known. One hundred and sixty-one non-related diabetic individuals and 142 non-related healthy controls were typed for the HLA DR-DQw-Dw association, using a restriction fragment length polymorphism (RFLP) typing method that combines three probe/enzyme systems: DRB/Taq I, DQB/Taq I, and DQB/Bam HI. Comparison of frequencies in both diabetics and controls confirms previous results in terms of HLA class II and IDDM association. Moreover, we have found that DR3/3 heterozygous individuals are more susceptible to IDDM when they are also Dw25 (associated with B18) than when they are Dw24 (associated with B8). Using oligonucleotide dot-blot hybridizations we analyzed the HLA-DQB1 sequence of DR3,Dw24 and DR3,Dw25 homozygous individuals, and we found no difference at position 57 between these two DR3-carrying haplotypes. This observation points to the heterogeneity of HLA genetic factors in IDDM susceptibility.

Alleles↗
PubMed1988

Use of synthetic oligonucleotides for genomic DNA dot hybridization to split the DQw3 haplotype.

Comparison of two different HLA-DQ beta gene sequences from two DR4 individuals, probably corresponding to DQw3.2 (DQR4) and DQw3.1 (DQR5) specificities, has shown several nucleotide variations. Eight oligonucleotides (24 bases long), derived from these polymorphic areas, have been synthesized. Each oligonucleotide was hybridized to BamHI-digested DNA samples from eight families with HLA-DR4 individuals. Four polymorphic BamHI fragments were detected. Two of eight oligonucleotides gave a single signal (8.9 kilobases) on DQw3.2-positive haplotypes. We used one of these oligonucleotides in a genomic DNA dot hybridization and detected a hybridization signal only in DQw3.2-positive individuals. A very simple test like this allows the screening of a large population sample within a very short period.

Base Sequence↗
PubMed1987

Small for dates: evaluation of different diagnostic methods.

Ninety-four high-risk pregnancies were studied weekly in a prospective and longitudinal study. Uterine height, biparietal diameter (BPD), cranial perimeter (CrP) and abdominal perimeter (AbP) were measured. Amniotic fluid volume (AFV) was assessed. Of the sample selected, 58 neonates were appropriate for gestational age and 36 were small-for-date (17 symmetrical and 19 asymmetrical). The sensitivity values in diagnosis of small-for-dates were: 67% for BPD, 42% for CrP, 94% for AbP, 56% for Uterine Height and 28% for AFV. The specificity for the five variables ranged from about 91% to 100%. If we consider symmetrical and asymmetrical retardation separately, the sensitivity values for the former were: 94%, 77%, 100%, 77% and 24% for BPD, CrP, AbP, Uterine Height and AFV respectively. For symmetrical retardation, the sensitivity values were: 43%, 11%, 90%, 37% and 32% for BPD, CrP, AbP, Uterine Height and AFV respectively. The fetal cranial measurements were the only ones to demonstrate a different pattern of evolution in symmetrical and asymmetrical small-for-dates. This is therefore a useful measurement in making a differential diagnosis between both retardations. The earliest diagnoses were made in the symmetrical small-for-date group.

Female↗
PubMed1987

[Alpha genes of the T cell receptor: a possible implication in genetic susceptibility to multiple sclerosis].

Multiple sclerosis (MS) is a neurological disease in which 60% of patients are DR2 (versus 20% in controls). Restriction fragment length polymorphism (RFLP) associated with T cell receptor alpha-chain and beta-chain genes have been analysed in a sample of 46 MS patients and compared with those of 142 controls. The alpha-chain gene polymorphism is localized to the V-J region and consists of 3 Bgl II alleles (alpha a = 3.2 kb; alpha b = 2.9 kb; alpha c = 2.8 kb). A significant difference was found in the distribution of these three alleles since 97% of DR2 patients versus 60% in DR2 non-MS individuals were found to be homozygotes alpha a/alpha a. These results suggest the influence of T cell antigen receptor germ line repertoire on the etiopathology of this disease.

Alleles↗
PubMed1986

Human enzyme polymorphism on the Canary Islands. I. Gran Canaria Island population.

Genetic polymorphism of seven red cell enzymes was examined in two Canary Island populations and in an Iberian peninsula sample. The more isolated insular population shows a considerable gene frequency heterogeneity when compared with the peninsular sample but both are within the range of European populations. The presence of certain rare alleles normally associated with blacks suggests an African component in the Canarian populations.

Alleles↗
PubMed1985

Influence of glucocorticoid and betamimetic therapy on milk secretory IgA concentration produced by mothers delivering preterm infants.

A prospective study was performed to find the possible difference in secretory IgA concentration in milk of mothers with term pregnancy labors and those delivering at earlier gestational ages. Since tocolytic drugs and/or glucocorticoid agents are usually given in cases of threatened premature labor, the pre-term group was divided into mothers with or without medication. Thirty two mothers were distributed in three groups: Group I, mothers with preterm labors without any medication; Group II, preterm labors with previous treatment with betamimetics and glucocorticoids; Group III, term labors (see Tab. I). In each of the three groups, three periods were studied: colostral (4 to 5 days postpartum), transitional (8 to 10 days), and mature (14 to 15 days). All mothers were healthy, with good nutritional state, without local inflammation and membranes had been ruptured 12 hours or less before labor. There was no significant difference in the proportion of primiparas and multiparas in both groups. The gestational age was evaluated by amenorrhea and neonatal examination. In all mothers milk was extracted with a vacuum pump to empty the mammary gland. The determinations were made using a specific antibody against the secretory component. The concentration of free secretory component in these milks was practically insignificant. No differences were found in the concentration of secretory IgA among the three groups (Tab. II, Fig. 1) in the periods that were studied, colostral, transitional or mature. The farther away from labor that milk extraction was made, in the periods considered in our study, there is a progressive decrease in the concentration of secretory IgA (Fig. 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Intrauterine and extrauterine growth of cranial perimeter in term and preterm infants. A longitudinal study.

In this study a cranial perimeter curve was established from 13 weeks of gestation to 6 months of postnatal life. Thirty cases were studied. The intrauterine section of the curve was derived from data obtained weekly by echography. The tenth and fiftieth percentiles of fetal measurements were greater than those described by other authors, who established intrauterine growth curves with data obtained after pretermed delivery. This pattern was used to assess the cranial perimeter growth to six months of corrected age in 48 preterm neonates of appropriate weight. Their values were below the standard at birth, reaching the normal measures on the expected date of confinement.

Cephalometry↗