Biomedical subjects

A B Perez

Publications and source records attributed to A B Perez.

5 recordsLinked to original sources

PubMed1999

Expansion of CTG repeat in myotonin protein kinase gene on Alu(ins)-HinfI-I background in a myotonic dystrophy patient from India. Mutations in brief no. 210. Online.

To determine the founder of Indian myotonic dystrophy mutation, we have studied the expansion of CTG repeats in myotonin protein kinase gene and two intragenic linked loci Alu(ins) / Alu(del) and G/T intron 9 HinfI polymorphism in ten unrelated DM patients from eastern India. Out of these ten patients, reconstruction of haplotype was possible for five patients unambiguously. In the other five cases, haplotype for the normal allele was assumed to be the most common haplotype found in normal individuals from Indian populations. Such analysis showed that in nine cases, the expansion of CTG repeats took place on Alu(ins)-HinfI-2 background indicating common founder with other DM mutation published. However, in one case we observed a different haplotype [Alu(ins)-HinfI-1] which could be a new mutation or due to admixture.

Deoxyribonucleases, Type II Site-Specific↗

PubMed1994

Transfer of dideoxyinosine across the human isolated placenta.

1. Dideoxyinosine (ddI) has recently been approved for the treatment of patients with HIV infection. As increasing numbers of such patients are pregnant, we wished to define the rate and mechanism(s) of ddI transfer by the placenta to the foetus. Using isolated single perfused human term placental cotyledons, the drug was shown to cross the placenta from mother to foetus at a rate of 25% that of a freely diffusible marker, antipyrine, and at about half the rate of zidovudine (AZT). The transfer of ddI was similar in both directions (maternal to foetal and the reverse), equal to that of L-glucose, a passively transported sugar, and was not inhibited by excess inosine or uric acid (structural analogues of ddI). ddI did not cross to the foetus against a concentration gradient. The transport process appeared to be passive and it was not altered by AZT. 2. ddI was not metabolized in the Krebs Ringer buffer/albumin perfusate, and placental homogenates converted only 4% of ddI to hypoxanthine over the 4 h incubation. However, when maternal term or cord blood was incubated with ddI for 3 h, 50% of the drug was converted to hypoxanthine in maternal blood and to hypoxanthine and uric acid in cord blood. 3. Thus, ddI metabolism in maternal blood should decrease its net transfer to the foetus in vivo. In the foetal circulation, ddI will be further metabolized by erythrocytes to hypoxanthine and possibly to uric acid. Hence, the fraction of administered ddI delivered to foetal tissues should be much lower than that of AZT.

Antipyrine↗

PubMed1993

Limb deficiency with or without Möbius sequence in seven Brazilian children associated with misoprostol use in the first trimester of pregnancy.

Misoprostol, a synthetic analog of prostaglandin, has been widely used in Brazil as an abortifacient. Abortion is illegal in Brazil. An uncertain number of these abortion attempts are unsuccessful and the pregnancy continues. We report on 7 patients whose mothers attempted to abort using this drug in the first trimester of gestation without success. The 7 patients presented with limb defects and in 4 of them a diagnosis of Möbius sequence was made.

Abnormalities, Drug-Induced↗

PubMed1992

Tradescantia-micronucleus (Trad-MCN) bioassay on clastogenicity of wastewater and in situ monitoring.

The Tradescantia-micronucleus (Trad-MCN) bioassay was used to determine the clastogenicity of wastewater samples collected from the Arena canal which contains effluent from the industrial district Benito Juarez of the city of Queretaro, Mexico. Fifteen wastewater samples which were collected, in most cases, at bi-weekly intervals beginning in September 1986 through February 1988, after a 3-fold dilution were used to treat Tradescantia plant cuttings. The clastogenicity expressed in terms of micronucleus frequencies of treated groups (30 h of treatment without recovery time) was significantly (0.01) higher than that of the tapwater control groups. The Trad-MCN bioassay was also used for in situ monitoring of air pollutants for the clastogenicity at 3 sites near the industrial and residential areas (Flores Magon, Conalep and Bellas Artes) of the city of Queretaro. Fourteen monitoring trips were made to each of the 3 sites at monthly intervals beginning in May 1988 through June 1990. Seasonal variation of micronucleus frequencies was exhibited with the peak clastogenicities shown in May and June 1988, June 1989 and April 1990 at the three sites. Micronucleus frequencies of all the exposed groups at the Conalep site, a predominantly industrial area, were markedly higher than that of the laboratory control groups throughout the 2-year period.

Environmental Monitoring↗

PubMed1992

Acyclovir transport by the human placenta.

Genital Herpes simplex infection is noted increasingly in women of childbearing age and in neonates. Concern about transmission of herpes to the newborn has led to cesarean delivery of many pregnant women with a history of genital herpes. Severe herpes hepatitis has also been noted in pregnancy. Acyclovir is the drug of choice for this infectious organism. Because there are no data on the mechanism(s) of transport of this drug by the human placenta, this study addressed this issue. We used normal term human placentas. For study of overall placental transport of acyclovir, we used the single, isolated perfused cotyledon technique. For assessment of initial acyclovir uptake, we used microvesicles prepared from the maternal-facing syncytiotrophoblast. Overall transfer of acyclovir at therapeutic concentrations from maternal to fetal compartment was at a rate of about 30% that of a freely diffusible marker, antipyrine. The overall transport was not saturable, was not inhibited by 50-fold adenine concentration, and did not proceed against a concentration gradient. There was no placental metabolism of the drug. Fetal-to-maternal transfer of acyclovir was at a similar rate. In maternal-facing microvesicles net uptake of acyclovir was not saturable, but was temperature dependent and was inhibited by high concentrations of adenine and ganciclovir, but not by nucleosides (adenosine, cytidine, cytosine). These data are most consistent with a carrier-dependent, nucleobase-type uptake of the drug, but passive overall net transfer of acyclovir, dependent on its solubility characteristics.

Acyclovir↗