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Biomedical subjects

G Porta

Publications and source records attributed to G Porta.

At least 37 records · Page 2Linked to original sources
PubMed1998

[3-Hydroxy-3-methyl-glutaryl-CoA-lyase deficiency as coma etiology in the neonatal period: case report].

We report a patient that presented two episodes of coma in the neonatal period, with severe metabolic acidosis and hypoglycemia, without ketosis. The urinary organic acid analysis showed increased amounts of 3-hydroxy-3-methyl-glutaric, 3-methylglutaconic, 3-methylglutaric and 3-hydroxyisovaleric acid. The deficiency of 3-hydroxy-3-methylglutaryl-CoA lyase was diagnosed by the clinical and metabolic features. This disease shows autosomal recessive inheritance and the treatment is done by a diet with restriction of protein (mainly leucine) and lipids, high in carbohydrate content, and the avoidance of fasting and carnitine supplementation.

Coma↗
PubMed1997

4.5-Mb YAC STS contig at 50-kb resolution, spanning Xq25 deletions in two patients with lymphoproliferative syndrome.

Sequence-tagged site (STS) content mapping in yeast artificial chromosomes (YACs) was used to cover the region deleted in two patients affected with X-linked lymphoproliferative disorder. The order of markers includes, centromere to telomere, DXS8009-DXS1206-DXS8078-DXS8044-DXS982- DXS6811-DXS8093-AFM240xblO- DXS75-DXS737-DXS100-DXS6-DXS1046-DXS803 8. The order of six major markers is confirmed by fluorescent in situ hybridization, and all the markers assigned by linkage mapping fall within a 1.6-cM interval. The contig comprises 90 clones containing 89 STSs, yielding a resolution of 50 kb; DNA in a gap just telomeric to DXS8044 has not been found in > 20 equivalents of YACs or bacterial clones. The two deletions were found to have centromeric breakpoints that lie close to DXS1206 and may be identical; the telomeric breakpoints are -150 kb apart, one falling between DXS737 and DXS100, the other between DXS100 and DXS1046. Several STSs near the breakpoints show weak amplification from more than one site; one gives products from three groups of YACs, and lie, respectively, within 50 kb of the centromeric and the two telomeric deletion borders. Such partially duplicated segments of DNA are candidates for involvement in the formation of the deletions.

Chromosome Deletion↗
PubMed1997

Liver biopsy in neonatal cholestasis: a review on statistical grounds.

The aim of this study was to improve the accuracy of the histopathologic diagnosis in the differential diagnosis between obstructive and nonobstructive forms of neonatal cholestasis, using this clinical situation as a model for a mathematical approach. The study was blind, and we performed it in two steps. In the first step, 49 histologic parameters were visually estimated and were scored on a scale of 0 to 4+ in 100 liver biopsy specimens obtained between 1980 and 1985 from 78 patients with neonatal cholestasis. Forty-eight of these 100 specimens were from patients with final diagnosis of obstructive cholestasis (Group I), and 52 were from patients with nonobstructive cholestasis (Group II). The age range was 3 to 24 weeks (median, 12.5 wk). Twelve histologic variables were selected by chi 2 and Fisher's exact test (P < .05). Next, a series of combinations among these variables were submitted to statistical analysis by logistic regression method, defining a six-variable model that had the most powerful predictive value to classify the type of cholestasis. The variables were portal ductal proliferation, bile plugs in portal bile ductules, portoportal bridges, neutrophils, hepatocyte swelling, and multinucleated giant hepatocytes. The score obtained by this model correspond to the probability of a case belonging to Group I. The accuracy, sensitivity, and specificity rates were 94.0%. In the second step, the model was applied to a new sample of 74 needle-liver biopsy specimens obtained between 1990 and 1995, 45 from patients in Group I and 29 from patients in Group II. The age range was 3 to 15 weeks (median, 8 wk). The accuracy, sensitivity, and specificity rates were 90.5%, 100%, and 75.9%, respectively. In our diagnostic routine, this score has been systematically reported and has been helpful in orienting the therapeutic decision in this group of patients.

Biliary Atresia↗
PubMed1996

Heat serum inactivation as a mandatory procedure for antiactin antibody detection in cell culture.

In autoimmune hepatitis (AIH), the smooth-muscle antibody is specific for polymerized actin. Detection of antiactin antibody (AAA) has been hampered by technical problems. We have investigated AAA in 30 sera from patients with liver diseases and smooth-muscle antibody. AAA was detected by indirect immunofluorescence in 1:40, 1:80, and 1:160 dilutions. Five techniques were performed using fibroblasts: with vinblastine (A); without drugs (B); with sodium citrate (C); without drugs but with heat serum inactivation (D); and with sodium citrate and heat serum inactivation (E). For comparative analysis, we considered: the total number of AAA-positive sera regardless of the dilution in which reactivity was observed, as well as in each dilution separately; and the comparison of AAA intensity between 1:40 x 1:80, 1:40 x 1:160, and 1:80 x 1:160 dilutions. AAA was more positive in techniques B, C, D, and E than in A (P < .001) in general, and in each dilution separately. AAA was more positive in technique D than in B in 1:40 (P = .0005) and 1:80 dilutions (P = .03), as well as in E than in C (P = .0001) in 1:40 dilution. Techniques B and D yielded results similar to C and E, respectively. AAA staining was significantly more intense in 1:80 and 1:160 than in 1:40 dilution in A, B, and C; it was both significantly less intense in 1:80 and 1:160 than in 1:40 dilution and in 1:80 than in 1:160 in techniques D and E. We concluded that heat inactivation increased AAA seropositivity/intensity in 1:40 and 1:80 dilutions, preventing false-negative results; actin polymerization with sodium citrate did not enhanced AAA seropositivity/intensity. The technique with vinblastine was the least effective.

Actins↗
PubMed1996

HIV-1 proviral DNA polymerase chain reaction detection in chorionic villi after exclusion of maternal contamination by variable number of tandem repeats analysis.

OBJECTIVE: The study of the placental HIV infection in cases of seropositive pregnant women after exclusion of maternal contamination of chorionic villi samples by variable number of tandem repeats (VNTR) analysis. METHODS: We studied 30 HIV-positive women: 17 terminated their pregnancy (11 in the first trimester and six in the second) and 13 delivered at term (one was a twin gestation). We selected chorionic villi and ruled out maternal contamination by VNTR analysis. DNA from chorionic villi and cord and maternal blood were tested for HIV by PCR. All infants underwent a paediatric follow-up. RESULTS: All maternal blood samples tested positive for HIV-1 by polymerase chain reaction. No maternal contamination was revealed and HIV was found in six out of 11 first trimester placentas, in all second trimester samples, and in 10 out of 14 at term. Cord blood tested positive in all second trimester cases and in seven out of 14 liveborns. In no case was HIV found in cord blood without infection of the corresponding placenta; conversely, three placentas tested positive but cord blood was negative. Two infants were HIV-positive, 11 were uninfected (one case was lost to follow-up). CONCLUSION: Our study indicates that HIV-1 can infect the placenta from first trimester onwards. HIV was found in two-thirds of our cord blood samples but it is possible that some viral DNA in cord blood may have come from infected placental cells. Additional studies are needed to assess the source of HIV in cord blood and the possible contribution of placental or maternal cells infected with HIV to vertical transmission of the virus.

Blotting, Southern↗
PubMed1996

Physical map and cosmid contig encompassing a new interstitial deletion of the X-linked lymphoproliferative syndrome region.

The X-linked lymphoproliferative syndrome (XLP) is an inherited immuno-deficiency to Epstein-Barr virus infection that has been mapped to chromosome Xq25. Molecular analysis of XLP patients from ten different families identified a small interstitial constitutional deletion in 1 patient (XLP-D). This deletion, initially defined by a single marker, DF83, known to map to interval Xq24-q26.1, is nested within a previously reported and much larger deletion in another XLP patient (XLP-739). A cosmid minilibrary was constructed from a single mega-YAC and used to establish a contig encompassing the whole XLP-D deletion and a portion of the XLP-739 deletion. Based on this contig, the size of the XLP-D deletion can be estimated at 130 kb. The identification of this minimal deletion, within which at least a portion of the XLP gene is likely to reside, should greatly facilitate efforts in isolating the gene.

Adolescent↗
PubMed1993

Alu and L1 sequence distributions in Xq24-q28 and their comparative utility in YAC contig assembly and verification.

The contents of Alu- and L1-containing TaqI restriction fragments were assessed by Southern blot analyses across YAC contigs already assembled by other means and localized within Xq24-q28. Fingerprinting patterns of YACs in contigs were concordant, and using software based on that of M. V. Olson et al. (1986, Proc. Natl. Acad. Sci. USA 83: 7826) to analyze digitized data on fragment sizes, fingerprinting itself could establish matches among about 40% of a test group of 435 YACs. At 100-kb resolution, both repetitive elements were found throughout the region, with no apparent enrichment of Alu or L1 in DNA of G compared to that found in R bands. However, consistent with a random overall distribution, delimited regions of up to 100 kb contained clusters of repetitive elements. The local concentrations may help to account for the reported differential hybridization of Alu and L1 probes to segments of metaphase chromosomes.

Chromosome Mapping↗
PubMed1993

High-resolution mapping of probes near the X-linked lymphoproliferative disease (XLP) locus.

Fluorescence in situ hybridization (FISH) was employed in high-resolution mapping of probes near the X-linked lymphoproliferative disease (XLP) locus. The map includes the DXS42, DXS12, DXS6, DXS982, DXS739, DXS75, DXS100, DXS10, and DXS177 loci. Metaphase analysis showed that DXS12 and DXS42 mapped to proximal Xq25, while DXS10 and DXS177 mapped to proximal Xq26.1. DXS6, DXS982, DXS739, DXS75, and DXS100 were in Xq25. The order of probes deduced from interphase FISH was: Xq24-(DXS12, DXS42)-DXS6-DXS982-DXS739-DXS75-DXS100+ ++-DXS10-DXS177-Xq26.2. We estimate that the entire region between DXS12 and DXS177 is about 7 Mb. Our previous study indicated that all three XLP deletions (63-3, 66-1, and 43-4) lacked DXS739. We now report that DXS75 and DXS982 are also missing in these deletions. Using interphase FISH measurements, we estimate that 2 Mb are absent in 63-3, and 4 Mb are absent in 66-1 and 43-4. This FISH map confines the XLP candidate gene region to a 2-Mb interval between DXS6 and DXS100 and places DXS100 distal to the XLP locus. This study also demonstrates that small probes (0.6 to 3.6 kb) can be utilized in FISH.

Chromosome Deletion↗
PubMed1991

The endoscopic and surgical management of portal hypertension in children: analysis of 123 cases.

Since 1973, 178 children with portal hypertension (PH) have been seen at Instituto da Criança of the University of São Paulo Medical School. Fifty-five of these children were excluded from this analysis for various reasons, including no treatment required, death before treatment, or incomplete data. From the remaining 123 children with esophageal varices, only 96 (76.1%) of them had at least one episode of upper gastrointestinal hemorrhage. Eighty-eight children were submitted to injection sclerotherapy; 26 treated prophylactically, and 62 for treatment of previous bleeding. Eleven (42.3%) children from the prophylactic group bled from esophageal varices during the treatment. They were all successfully managed thereafter. Satisfactory results were achieved in 53 (85.4%) children in the therapeutic group. Twenty-eight (45.1%) children had at least one episode of bleeding after beginning of sclerotherapy, 19 of whom eventually had successful control of the variceal bleeding. From 1973 to 1984, distal splenorenal shunt (DSS) was the procedure of choice for the treatment of bleeding esophageal varices. Forty-two children have undergone DSS during this period. Only one child was shunted prophylactically. Since 1985, injection sclerotherapy has been the first choice for the treatment and only seven children with sclerotherapy failure have since been treated by DSS. Characteristically these children had very similar splenoportographic pattern with huge esophageal and gastric varices and deviation of portal vein blood flow toward the left gastric vein.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Yeast artificial chromosome-based genome mapping: some lessons from Xq24-q28.

Yeast artificial chromosomes (YACs) have recently provided a potential route to long-range coverage of complex genomes in contiguous cloned DNA. In a pilot project for 50 Mb (1.5% of the human genome), a variety of techniques have been applied to assemble Xq24-q28 YAC contigs up to 8 Mb in length and assess their quality. The results indicate the relative strength of several approaches and support the adequacy of YAC-based methods for mapping the human genome.

Chromosome Mapping↗
PubMed1991

Is there a role for pericytic cells in the vascular bed of infantile hemangioendothelioma of the liver?

Electron microscopic examination of an infantile hemangioendothelioma (IHE) type I of the liver, appearing in a five month old child, showed a high density of pericytes in the walls of the neoplastic vessels. These vessels, in part of the IHE patients, establish an important arteriovenous shunt leading to high output, congestive cardiac failure. It is unclear whether functions ascribed to pericytes, such as participation in microvascular contractility or as suppressors of endothelial cell proliferation are involved in two noteworthy aspects of the present case. The child exhibited no congestive heart failure and the multiple nodular lesions underwent spontaneous regression.

Endothelium, Vascular↗
PubMed1990

Anti-liver-kidney microsome antibody-positive autoimmune hepatitis presenting as fulminant liver failure.

A 17-month-old girl presented with acute hepatitis, which took a fulminant course leading to death 2 months after onset. No known cause of fulminant liver failure could be identified. Postmortem examination of the liver showed massive multilobular necrosis and areas of severe piecemeal necrosis. A high level of total serum gamma-globulins raised the possibility of autoimmune hepatitis. Search for anti-liver-kidney microsome antibody in the patient's serum was positive by immunofluorescence and enzyme-linked immunosorbent assay. Western blot analysis showed reactivity of the antibody with a 50-kDa protein identical to that observed in children with autoimmune hepatitis. This patient's history strongly suggests that autoimmune hepatitis can present as fulminant liver failure in children. Early diagnosis in such a patient could lead to early immunosuppressive therapy.

Antibodies↗
PubMed1990

Human Xq24-Xq28: approaches to mapping with yeast artificial chromosomes.

One hundred twenty-seven yeast strains with artificial chromosomes containing Xq24-Xqter human DNA were obtained starting from a human/hamster somatic cell hybrid. The clones were characterized with respect to their insert size, stability, and representation of a set of Xq24-Xqter DNA probes. The inserts of the clones add up to 19.3 megabase (Mb) content, or about 0.4 genomic equivalents of that portion of the X chromosome, with a range of 40-650 kb in individual YACs. Eleven clones contained more than one YAC, the additional ones usually having hamster DNA inserts; the individual YACs could be separated by extracting the total DNA from such strains and using it to retransform yeast cells. One of the YACs, containing the probe for the DXS49 locus, was grossly unstable, throwing off smaller versions of an initial 300-kb YAC during subculture; the other YACs appeared to breed true on subculture. Of 52 probes tested, 12 found cognate YACs; the YACs included one with the glucose-6-phosphate dehydrogense gene and another containing four anonymous probe sequences (DX13, St14, cpx67, and cpx6). Xq location of YACs is being verified by in situ hybridization to metaphase chromosomes, and fingerprinting and hybridization methods are being used to detect YACs that overlap.

Animals↗
PubMed1989

Yeast artificial chromosomes with 200- to 800-kilobase inserts of human DNA containing HLA, V kappa, 5S, and Xq24-Xq28 sequences.

Sequences hybridizing to several human gene probes have been recovered as cloned inserts in yeast artificial chromosomes (YACs). Among 2300 YACs made from human leukocyte DNA (totaling about 0.1 genomic equivalent of human DNA) we have found two, 200 and 780 kilobases (kb), containing sequences of V kappa I immunoglobulin (V = variable); one, 240 kb, with class I HLA; and 11, 200-800 kb, with 5S rRNA-encoding DNA (rDNA). Fifty human YACs from a hamster-human cell hybrid with only the Xq24-Xq28 portion of the X chromosome include one that contains two anonymous probe sequences, DX13 and St14, previously inferred by indirect means to lie within about 70 kb of one another in Xq28. The YACs specific for human DNA arise at a frequency equivalent to the fraction of cellular DNA that is human-specific. Furthermore, the human YACs, formed in a 280-fold excess of hamster DNA, do not hybridize to a hamster DNA probe, indicating that individual YACs do not contain a combination of human and hamster DNA. To confirm that sequences are not scrambled, the YACs containing V kappa I or DX13 and St14 sequences were shown to produce restriction fragments identical in mobility to fragments detected by the same probes in total human DNA digested with the same enzymes. YACs may therefore provide large clones to bridge gene mapping at the chromosome level to molecular analyses of small fragments of genomic DNA.

Animals↗
PubMed1988

Rhodanese isozymes in human tissues.

An investigation of a range of tissue homogenates by various electrophoretic methods, followed by staining for specific enzyme activity, has revealed a series of isozymes of human rhodanese. Polyacrylamide gel isoelectric focusing provided the most data and rhodanese activity was found in all of the tissues examined. The simplest isozyme pattern was found in red cell lysates; liver homogenates generated the most complex pattern which included the 'red cell' forms together with a set of more basic 'tissue' isozymes. Variation in isozyme patterns thought to be attributable to storage changes affecting reactive sulphydryl residues was observed in 'red cell' rhodanese but no genetic variants of either 'red cell' or 'tissue' rhodanese were encountered in a study of material from the European population. We conclude that 'red cell' and 'tissue' rhodanese are determined by separate genes but more than one locus may be concerned with the synthesis of the heterogeneous 'tissue' isozymes.

Electrophoresis, Polyacrylamide Gel↗