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Biomedical subjects

M Herrera

Publications and source records attributed to M Herrera.

At least 19 recordsLinked to original sources
PubMed1992

Parathyroid autotransplantation.

Although rare following initial cervical exploration, reoperative parathyroid surgery may cause permanent hypoparathyroidism in 15% to 30% of patients. Immediate fresh or delayed cryopreserved parathyroid autotransplantation is the principal surgical option to resolve this complication. Between 1980 and 1990, 18 and 12 patients underwent immediate and cryopreserved autotransplantation, respectively. With a mean follow-up of nearly 5 years, 61% of the immediate and 42% of the cryopreserved tissue showed evidence of function. However, only 10 (55%) and two (17%) of the respective patients had completely discontinued treatment with calcium supplementation. Graft-dependent hypercalcemia can occur with either technique. We conclude that until cryopreserved tissue can be transplanted with more reliable success and if the excised abnormal parathyroid likely represents the only remaining gland, we would advise immediate autotransplantation. In the reoperative setting, unless a residual normal parathyroid gland is confirmed, a portion of the excised parathyroid tissue should be cryopreserved for possible autotransplantation in case hypoparathyroidism develops subsequently.

Cryopreservation↗
PubMed1992

Effectiveness of continuous vs. intermittent amoxicillin to prevent episodes of otitis media.

The effectiveness of continuous compared with intermittent amoxicillin prophylaxis administered to subjects with a history of recurrent otitis media enrolled during the winter respiratory infection season was assessed in a prospective single blinded clinical trial. Patients with three or more chart-documented episodes of otitis media (OM) in the preceding 6 months were enrolled and randomly assigned to each treatment group. Patients in the continuous group received amoxicillin twice a day every day for up to 4 months. During the same period patients in the intermittent group received amoxicillin twice a day only when they developed respiratory symptoms of congestion, runny nose or cough. Among the 30 patients receiving continuous amoxicillin who were followed for at least 3 months, 22 (73%) had no OM episodes and 8 (28%) had one OM episode. Among the 25 patients receiving intermittent amoxicillin for at least 3 months, 13 (52%) had no OM episodes, 8 (32%) had 1 episode and 4 (16%) had 2 episodes. Significantly fewer patients had fewer than 2 OM episodes on continuous compared with intermittent amoxicillin (P less than 0.04). The incidence density was 0.46 episode/120 days at risk in the continuous treatment group compared with 1.10 episodes/120 days at risk for intermittent treatment (P less than 0.03). Among patients 12 months or older the incidence density of OM episodes per 120 days was 3.5 times higher in the intermittent amoxicillin group (0.80) compared with the continuous amoxicillin group (0.23) (P = 0.05). The incidence densities of the continuous vs. intermittent therapy groups did not differ significantly for patients younger than 12 months of age. The findings suggest that continuous amoxicillin prophylaxis may be more effective than intermittent treatment in preventing OM episodes in patients 12 months or older with a history of recurrent otitis media.

Amoxicillin↗
PubMed1991

Polymorphism of the alleles of the merozoite surface antigens MSA1 and MSA2 in Plasmodium falciparum wild isolates from Colombia.

The degree of polymorphism and the allelic distribution of 2 major Plasmodium falciparum merozoite surface antigens (MSA1 and MSA2) have been analysed in clinical isolates from Colombia. DNA was prepared directly from patients' blood and used in PCR reactions to amplify block 2 of MSA1 and the central region from MSA2. Thirty one samples were analysed and a marked degree of length polymorphism was detected, especially for MSA2. A high proportion of multiple bands was also observed, most probably resulting from mixed infections. Allele-specific oligonucleotides were used to type both alleles. For MSA1, 26 out of 31 clinical isolates were of the RO33 type, 15 were MAD20 and three were typed as KI. When the MSA2 allele was analysed, 7 isolates hybridised with a CAMP specific probe and 6 hybridised strongly with an FC27-derived oligonucleotide. Two samples, which showed multiple bands, hybridised with both probes. Interestingly, in 14 out of 27 isolates the MSA2 allele remained unassigned by the specific probes. Five of these were cloned and their DNA sequenced; these sequences are discussed.

Adolescent↗
PubMed1991

Complete nucleotide sequence of a genomic clone encoding HLA-B35 isolated from a Caucasian individual of Hispanic origin. Identification of a new variant of HLA-B35.

The primary structure of an HLA class I genomic clone isolated from a homozygous HLA-B35 Caucasian individual of hispanic origin was determined. The nucleotide sequence of exons 1, 2, 4, 5, 6, and 7 is identical to that of the HLA-B35 allele of Oriental origin reported previously. Exon 3 differs in only three nucleotides present in a stretch of 23 bp. These changes introduce three amino acid substitutions in residues 109 (Leu----Phe), 114 (Asp----Asn), and 116 (Ser----Tyr), two of which (114 and 116) are located in one of the beta sheets at the bottom of the peptide binding site. The nature of these replacements in this HLA-B35 variant is likely to affect peptide binding and recognition by T lymphocytes. Introns 1, 2, 3, 4, 5, and 6 from this genomic clone are identical to those present in HLA-Bw58, further confirming the evolutionary origin of HLA-B35.

Amino Acid Sequence↗
PubMed1991

[The antioxidative activity of drugs in the liver microsomal system of rats].

The antioxidative properties of drugs--diethylcarbamazine citrate--DECC, dipyridamole-DP, levamisole and labinzarit--have been investigated in various microsomal lipid peroxidation (LPO) models: NADPH-, ascorbate- and CCl4-dependent. The most strong antioxidant of direct action turned out to be DP, DECC exhibited the antioxidative properties as a result of metabolic activity in monooxygenases system of rat liver microsomes. Levamisole and labinzarit turned out to be weak antioxidants. The control of microsomal membrane stability against Fe(2+)-ADP, NADPH-induced LPO, after being isolated from rat liver after the action of CCl4 without and with DECC, showed that DECC protected microsomal membranes from CCl4 in vivo and they remained stable against LPO in vitro.

Animals↗
PubMed1991

[Cystic fibrosis. Prenatal diagnosis].

The clinical case of heterozygote parents, both bearers of cystic fibrosis, whose three newborn infants died of this disease is presented. The authors describe the prevention of and the progress in its early prenatal diagnosis and management.

Carrier State↗
PubMed1991

[Myocardial involvement in 2 women, carriers of Duchenne de Boulogne muscular dystrophy].

Duchenne muscular dystrophy is the commonest genetic muscular disease. The prognosis, which depends on cardiac involvement, is poor. In boys, this takes the form of a hypokinetic cardiomyopathy particularly affecting the postero-lateral wall of the left ventricle which then dilates. The recent identification of the gene which transmits the disease on the X chromosome and of the coded protein, dystrophin, has improved our understanding of the disease. We report two cases of isolated cardiac involvement in two female carriers of the disease, classically thought to be unaffected. They presented with apparently idiopathic dilated cardiomyopathies. These cases show that Duchenne muscular dystrophy is an original example of a genetically determined diffuse muscular disease with cardiac involvement.

Adult↗
PubMed1990

[Surgical mitral valvuloplasty in the treatment of mitral valve diseases].

Mitral valve repair surgery, in presence of a pure mitral leakage or one associated to a stenosis, is not only possible but has been well codified for a decade. According to damage, there are two methods of operation: valvular mobilization surgery and valvular motion amplitude reduction surgery. They are usually associated to annuloplasty with a Carpentier prosthetic ring. The incidence of late mortality is of 0.6 p. 100 pt/yr, that is to say 91.7 p. 100 at 13 years. This late survival rate is about 20 p. 100 better than for a valvular replacement. Reoperations rate is 1.6 p. 100 pt/yr. The incidence of thromboembolic event occurrence is low: 0.5 p. 100 pt/yr. The ideal indications for mitral valve repair are represented by damage of prolapse from a degenerative origin for which results are better and more constant. For rheumatic damage, the valvular repair indication depend on the valvular tissue elasticity and area. The presence of calcification and extensive fibrosis remain on principle counter-indications.

Adult↗
PubMed1990

Mutagenicity of N-nitrosomorpholine biosynthesized from morpholine in the presence of nitrate and its inhibition by ascorbic acid.

N-nitrosomorpholine biosynthesis and inhibition in mice treated with nitrate, morpholine and ascorbic acid, was studied by means of the mutagenic activity in urine samples. The preincubation method was used and Salmonella typhimurium TA 1535 was the test strain. The results suggest that N-nitrosomorpholine biosynthesis was carried out when the animals were fed high doses of nitrate, however ascorbic acid was an inhibitor of this process.

Animals↗
PubMed1990

Successful diaphragmatic pacing for idiopathic alveolar hypoventilation.

We describe the case of a 17-year-old woman noted to have idiopathic alveolar hypoventilation, with multiple Intensive Care Unit (ICU) admissions because of acute respiratory failure (ARF) due to respiratory infections. After two years of diaphragmatic pacing arterial blood gases have substantially improved, without obstructive apnoea. Signs of right ventricular enlargement and pulmonary hypertension have decreased. Morning headache and diurnal somnolence have disappeared, and she is also able to perform more physical and mental activity, allowing her to enjoy a better quality of life.

Adolescent↗
PubMed1989

Restriction fragment length polymorphism in HLA class II genes of Latin-American Caucasian celiac disease patients.

In the present study Latin-American celiac disease patients were analyzed for the frequency of certain HLA class II restriction fragment length polymorphisms in order to investigate whether they exhibited the normal associated alleles or showed unusual class II variants. A DPB/RsaI 4.0-kb fragment that was shown to be significantly increased among North Americans celiac disease patients of the DR3,DQw2 haplotype was found with similar frequency in Latin-American control and celiac disease individuals. A DPA/BglII 3.7-kb fragment previously shown to be increased among British celiac disease patients was also present with similar frequency among Latin-American control and celiac disease individuals. These results show that the frequency of the HLA-DP region-derived restriction fragment length polymorphisms linked to celiac disease differs between Caucasian populations of different ethnic backgrounds (Anglo-Saxon and Latin-American). On the other hand, DNA samples from 13 patients and 14 controls bearing the DR5/DR7 phenotype (which is significantly associated with celiac disease in Latin populations) were investigated for the presence of particular restriction fragment length polymorphisms disproportionally present in celiac disease individuals. No significant differences were found between controls and patients when the DNA was analyzed with 10 different restriction enzymes and probes for DRB, DQA, DQB, and DPB HLA class II sequences.

Alleles↗
PubMed1989

False-positive radionuclide hepatobiliary imaging following cystic duct stone removal.

The authors report a case in which a radionuclide hepatobiliary image was falsely indicative of cystic duct obstruction in a patient with an indwelling cholecystostomy tube and an externalized gallbladder-duodenal stent. Cystic duct patency was demonstrated radiographically shortly before and after the radionuclide study. The authors recommend that cystic duct obstruction indicated by a radionuclide hepatobiliary image be confirmed by another means if a cholecystostomy tube is present, or if the patient recently has undergone percutaneous gallbladder or cystic duct manipulations.

Aged↗
PubMed1989

[HLA and disease in Argentina. Serologic and genomic polymorphism].

In this report we discuss the results of the association of chronic active hepatitis (B virus) and coeliac disease with HLA class I and class II antigens, in patients of Latin American Caucasian origin. Evidence is presented showing that the alleles involved differ from those reported in other Caucasian populations of different ethnic background. Differences were observed both at the serology and at the DNA (RFLP) level. The relevance of these findings regarding the clinical implications as well as the molecular mechanisms involved in the associations are discussed.

Argentina↗