Search PubMed⌕ Search

Biomedical subjects

M Molina

Publications and source records attributed to M Molina.

At least 73 records · Page 4Linked to original sources
PubMed1998

Functional results of laparoscopic fundoplication in children.

BACKGROUND: There is no evidence that the results of laparoscopic fundoplication in children match those of the open procedure. In the current report, pre- and postoperative function of the antireflux barrier is examined in children having laparoscopic fundoplication for gastroesophageal reflux. METHODS: Twenty-seven patients with gastroesophageal reflux, aged 7.2+/-4.5 years, were operated on for unremitting gastrointestinal symptoms (n = 24), with respiratory tract disease (n = 11), cystic fibrosis (n = 2), or brain damage (n = 11). Gastrostomy was added in 5 cases. Barium contrast study, pH-metering, endoscopic examination, and biopsy were performed before and after a median of 19 months (range, 8 to 46) after operation. RESULTS: At diagnosis, 15 of 21 patients had esophagitis that was moderate or severe in 11 (1 with Barrett's esophagus). Symptoms disappeared after fundoplication in all but 2 patients, in whom they became milder. The reflux index decreased from 20.2+/-20% to 4.9+/-9% and became normal in all except 4 children (2 with brain damage and 1 with cystic fibrosis). Open repair of the failed wrap was considered necessary in only 1 of them. CONCLUSIONS: Laparoscopic fundoplication is as effective as the open procedure (14% overall failure rate). However, the failure rate in neurologic patients (18%) suggests that before reaching conclusions on the benefits of this approach, careful long-term assessment of the functional results is necessary.

Biopsy↗
PubMed1998

Molecular study of the rhodopsin gene in retinitis pigmentosa patients in the Basque Country.

Retinitis pigmentosa (RP) is a degenerative disorder affecting the outer segment of the retina and leading to night blindness and progressive visual field loss. The rhodopsin gene encodes a photolabile pigment located in the rod outer segments constituting around 80-90% of its protein content and is the initiation point for the visual cascade upon absorption of a single photon. Seventy-five unrelated, isolated RP families in the Basque Country, with at least one affected member, were diagnosed at our hospital after ophthalmic examination and electroretinogram analysis. The patients received genetic counselling according to their individual case based on their clinical diagnosis. The modes of inheritance found from pedigree studies were the following: 20% (15/75) were classified as autosomal dominant retinitis pigmentosa (ADRP), 17.33% (13/75) were autosomal recessive (ARRP), 2.66% (2/75) were unclassified (NC), and 60% (45/75) were sporadic cases (SCRP). From these families, 75 unrelated and affected index cases together with 22 affected relatives and 42 unaffected relatives were screened for mutations in the rhodopsin gene by GC clamped denaturing gradient gel electrophoresis. Our results showed that five ADRP, three ARRP, 15 SCRP, and one NC families had alterations in this gene. Only three of these alterations, that is 4% (3/75) (95% CL 0-8), appeared to be responsible for the disease. This represents a lower percentage than the 10% previously reported.

Electrophoresis, Polyacrylamide Gel↗
PubMed1998

Indications and counterindications for cochlear implantation in children.

OBJECTIVE: This study is aimed to analyze the current indications and counterindications of cochlear implantation (CI) in children. STUDY DESIGN: This study reviews the children implanted in our institution looking specifically at the following aspects: 1) auditory criteria for candidate selection; 2) age at implantation; 3) educational environment; and 4) associated handicapping conditions. SETTING: Tertiary referral center with experience in CI since 1989 with inpatient and outpatient care. INTERVENTION: All children received a Mini Nucleus 22 CI device (Cochlear Limited, Australia) in a standard surgical procedure. RESULTS: Regarding auditory criteria, children with average hearing level of 100-105 dB HL are more likely to obtain benefit from a CI than from a hearing aid. The minimum age for CI should be as soon as there is a reliable diagnosis of bilateral profound hearing loss, while the maximum age for CI depends on strict selection criteria of candidates. The educational environment is of a great importance in the rehabilitation process, permitting a progressive change to oral communication. Our experience in CI of children with multiple handicapping conditions is limited to a case of a deaf-blind child who was implanted with a good performance. In the selection of these children it is mandatory to have extensive multidisciplinary evaluation. CONCLUSIONS: An experienced team is needed in the selection of children for CI. Candidates should meet anatomic criteria, have a reliable diagnosis of bilateral profound hearing loss, an evaluation of communication skills, and extensive neuropediatric and socioeducational evaluation.

Adolescent↗
PubMed1998

[Impact of hypertensive disease of pregnancy on intrauterine growth retardation].

BACKGROUND: Intrauterine growth retardation, associated to hypertensive disease of pregnancy, is responsible for a higher perinatal mortality and morbidity. AIM: To assess obstetrical, perinatal and neonatal features of intrauterine growth retardation associated to hypertensive disease of pregnancy. PATIENTS AND METHODS: One hundred thirty seven newborns with intrauterine growth retardation, whose mothers had hypertensive disease of pregnancy, were compared to 165 similar newborns but whose mothers did not have the disease. RESULTS: The incidence of intrauterine growth retardation associated to hypertensive disease of pregnancy was 45.4%. Maternal obesity at the start and end of pregnancy, a pregestational weight over 65 kg and a weight increment of more than 20 kg during pregnancy were risk factors for hypertensive disease of pregnancy with relative risks of 1.76, 1.62, 1.62 and 2.09 respectively. Relative risks for cesarean section and prematurity were also higher among women with hypertensive disease of pregnancy. Intrauterine growth retardation associated to maternal hypertension was symmetrical and severe in 37.9% of newborns. All seven neonatal deaths occurred in newborns with severe retardation. CONCLUSIONS: Neonatal and perinatal morbidity and mortality are higher in newborns with intrauterine growth retardation. Hypertensive disease of pregnancy was associated with a twice higher incidence of asymmetrical intrauterine growth retardation.

Birth Weight↗
PubMed1998

[Lipids, lipoproteins and apolipoproteins in normal newborns].

BACKGROUND: In Chile, there is a high prevalence of cardiovascular diseases. Because atherosclerosis starts in childhood, it is important to assess serum lipid levels in children. AIM: To measure serum lipid levels in normal Chilean newborns. SUBJECTS AND METHODS: A sample of umbilical cord venous blood was obtained from 156 normal newborns (76 male) immediately after delivery. Total and HDL cholesterol, triglycerides, apoprotein A1, B and lipoprotein (a) were measured. RESULTS: Mean values for total cholesterol in males, females and in the total sample were 60.6, 67.8 and 64 mg/dl respectively. The figures for HDL cholesterol were 24.9, 29.3 and 27 mg/dl, for LDL cholesterol were 28.3, 32.4 and 30 mg/dl, for triglycerides were 37.5, 30.3 and 35 mg/dl, for apoprotein A1 were 69, 79 and 74 mg/dl, for apoB were 23, 25 and 24 mg/dl and for lipoprotein (a) were 1.58, 1.79 and 1.69 mg/dl. Total cholesterol, HDL cholesterol, triglycerides and apoprotein A1 were significantly different between sexes. Percentiles 5 and 95 for total cholesterol were 37 and 111, for HDL cholesterol were 14 and 40, for LDL cholesterol were 13 and 57, for triglycerides were 20 and 69, for apoprotein A1 were 53 and 101, for apoprotein B were 11 and 48 and for lipoprotein (a) were 1.3 and 2.1 mg/dl. Five percent of children had apoprotein B values over 48 mg/dl. CONCLUSIONS: The detection of high levels of apoprotein B in newborns, could allow the early identification of individuals with high cardiovascular risk.

Apolipoprotein A-I↗
PubMed1997

Characterization of SKM1, a Saccharomyces cerevisiae gene encoding a novel Ste20/PAK-like protein kinase.

Ste20/PAK serine/threonine protein kinases have been suggested as playing essential roles in cell signalling and morphogenesis as potential targets of Cdc42 and Rac GTPases. We have isolated and characterized the Saccharomyces cerevisiae SKM1 gene, which codes for a novel member of this family of protein kinases. The amino acid sequence analysis of Skm1p revealed the presence of a PH domain and a putative p21-binding domain near its amino terminus, suggesting its involvement in cellular signalling or cytoskeletal functions. However, deletion of SKM1 produced no detectable phenotype under standard laboratory conditions. Moreover, disruption of each of the two other S. cerevisiae Ste20/PAK-like kinase-encoding genes, STE20 and CLA4, in skm1 backgrounds, showed that Skm1p is not redundant with Ste20p or Cla4p. Interestingly, overexpression of SKM1 led to morphological alterations, indicating a possible role for this protein in morphogenetic control. Furthermore, overproduction of Skm1p lacking its N-terminus caused growth arrest. This effect was also seen when similarly truncated versions of Ste20p or Cla4p were overexpressed. We further observed that overproduction of this C-terminal fragment of Skm1p complements the mating defect of a ste20 mutant strain. These results suggest that the N-terminal domains of S. cerevisiae Ste20/ PAK-like protein kinases share a negative regulatory function and play a role in substrate specificity.

Amino Acid Sequence↗
PubMed1997

Effects of aspirin or basic amino acids on collagen cross-links and complications in NIDDM.

OBJECTIVE: To determine if long-term therapy with aspirin or basic amino acids for subjects with NIDDM reduces the severity of clinical complications and/or reduces tissue levels of markers of glycooxidative damage. RESEARCH DESIGN AND METHODS: Subjects with NIDDM were administered either aspirin (100 mg/day) or a combination of basic amino acids consisting of L-arginine (2 g/day) plus L-lysine (0.5 g/day) for 1 year. The study was double-blind and placebo-controlled. The presence and severity of retinopathy, nephropathy, and neuropathy were assessed in all subjects at 4-month intervals, as were serum blood glucose, glycohemoglobin levels, and presence of albuminuria. Collagen cross-linking and collagen glycation were measured in skin collagen obtained by biopsy at the beginning and the end of the study. Skin biopsies were also obtained from age-matched control subjects. RESULTS: Skin samples obtained from NIDDM subjects at the beginning of the study had significantly increased levels of glucitolyllysine, pentosidine, and hydroxypyridinium, as compared with age-matched control subjects. Pentosidine levels were significantly correlated with severity of retinopathy and neuropathy, but not nephropathy. Subjects receiving aspirin, but not amino acids or placebo, had significantly decreased levels of skin pentosidine after 1 year of therapy. CONCLUSIONS: It is concluded that 1) low-dose aspirin may reduce glycooxidative damage in people with NIDDM, and 2) treatment may need to continue for more than 1 year before clinical status improves.

Analysis of Variance↗
PubMed1996

HLA-DR4-IE chimeric class II transgenic, murine class II-deficient mice are susceptible to experimental allergic encephalomyelitis.

To investigate the development of HLA-DR-associated autoimmune diseases, we generated transgenic (Tg) mice with HLA-DRA-IE alpha and HLA-DRB1*0401-IE beta chimeric genes. The transgene-encoded proteins consisted of antigen-binding domains from HLA-DRA and HLA-DRB1*0401 molecules and the remaining domains from the IE(d)-alpha and IE(d)-beta chains. The chimeric molecules showed the same antigen-binding specificity as HLA-DRB1*0401 molecules, and were functional in presenting antigens to T cells. The Tg mice were backcrossed to MHC class II-deficient (IA beta-, IE alpha-) mice to eliminate any effect of endogenous MHC class II genes on the development of autoimmune diseases. As expected, IA alpha beta or IE alpha beta molecules were not expressed in Tg mice. Moreover, cell-surface expression of endogenous IE beta associated with HLA-DRA-IE alpha was not detectable in several Tg mouse lines by flow cytometric analysis. The HLA-DRA-IE alpha/HLA-DRB1*0401-IE beta molecules rescued the development of CD4+ T cells in MHC class II-deficient mice, but T cells expressing V beta 5, V beta 11, and V beta 12 were specifically deleted. Tg mice were immunized with peptides, myelin basic protein (MBP) 87-106 and proteolipid protein (PLP) 175-192, that are considered to be immunodominant epitopes in HLA-DR4 individuals. PLP175-192 provoked a strong proliferative response of lymph node T cells from Tg mice, and caused inflammatory lesions in white matter of the CNS and symptoms of experimental allergic encephalomyelitis (EAE). Immunization with MBP87-106 elicited a very weak proliferative T cell response and caused mild EAE. Non-Tg mice immunized with either PLP175-192 or MBP87-106 did not develop EAE. These results demonstrated that a human MHC class II binding site alone can confer susceptibility to an experimentally induced murine autoimmune disease.

Amino Acid Sequence↗
PubMed1996

Molecular and functional characterization of a mutant allele of the mitogen-activated protein-kinase gene SLT2(MPK1) rescued from yeast autolytic mutants.

We have further characterized the functionality of the Saccharomyces cerevisiae gene SLT2(MPK1), coding for a MAP-kinase homolog essential for cell integrity, which is involved in the Pkc1p signalling pathway. This gene was isolated on the basis of its capacity to complement the thermosensitive-autolytic, osmotic-remediable phenotype of lyt2 mutants. Both slt2delta and lyt2 mutants displayed a caffeine-sensitive phenotype consisting of cell lysis that was not dependent on temperature. Caffeine concentrations affecting the growth of these mutant strains were dependent on the genetic background, the SSD1 allele being very significant in this regard. The SLT2 allele of several lyt2 strains was both rescued and amplified by PCR. The recovered allele was shown to be non-functional as it could not complement the lytic phenotype of both deletion (slt2delta) and lyt2 strains. After nucleotide sequencing of the recovered allele, we found that the defect of lyt2 mutants consists in a substitution of an aspartic acid for a glycine at position 35 of the amino-acid sequence of Slt2p. Gly35 is the third glycine of a glycine cluster (Gly-X-Gly-X-X-Gly), a conserved region in protein kinases and other nucleotide-binding proteins. Keywords Yeast middle dot SLT2 middle dot MAP-kinase middle dot Caffeine

Alleles↗
PubMed1996

A reliable method for Golgi staining of retina and brain slices.

Although the classical Golgi method is a powerful means for structural analysis of the brain, it is generally considered to be an unpredictable technique making anatomists wary of using it. Often, even when successful staining has occurred, deposits of silver chromate crystals on the surface of the tissue obscure examination. This paper describes a simple procedure for Golgi impregnation of retina and brain slices so that good, even staining is obtained and crystal formation is avoided. The most outstanding feature of the method is the consistency of results. This consistency is due to two factors: (1) the accurate determination of the optimal chromation by measuring the rise of pH in the solutions and (2) the uniform penetration of dichromate and silver nitrate to the specimen by using a freely hanging, sandwiching technique. We suggest that the method described here can be applied to other parts of the nervous system and will be a reliable way to identify and better classify new cell types.

Animals↗
PubMed1996

Raphe-septal neurons changes in sensitivity to desipramine following an early septal lesion in the rat.

1. The electrophysiological responsivity to desipramine (DMI) applied by systemic or local route was tested in Wistar female rats submitted to a wide lesion in the lateral septal area on the 8th day after birth. 2. One year after a septal lesion, the dorsal raphe nucleus (DRN) stimulation produced an initial brief response in lateral septal and CA1/CA3 neurons. In the control and sham-lesion groups, most recordings showed only this initial brief response (non-late responding neurons); however, in the lesion group most of the recorded neurons showed an afterdischarge. 3. DMI (2.14 mg/kg, 21 days, i.p.) increased the firing rate in septal and CA1/CA3 non-late responding neurons. In the equivalent septal neurons from lesion group, DMI produced the inverse effect, i.e., a decreased firing rate. 4. In septal non-late responding neurons, DMI (2 mM; 10-15 nAmps, 0.5 sec) applied by microiontophoresis increased the firing rate only after long-term systemic DMI impregnation. The response to locally applied DMI did not occur in the lesion group even after long-term DMI treatment. 5. In conclusion, an early lateral septal lesion canceled the response of intermediate-dorsal septal neurons to DMI applied by systemic and local routes.

Animals↗
PubMed1996

Raman spectroscopic determination of thymidine nucleoside structures in nucleotides.

Several spectral differences in Raman spectra were observed for thymidine (TM), 3'-O-acetylthymidine (3'OATM), 3',5'-di-O-acetylthymidine (3'5'DOATM), thymidine 5'-monophosphoric acid (H2TMP) and its Ca2+, Sr2+ and Ba2+ salts owing to nucleoside conformational differences in the thymidine moiety. The spectroscopic characterization of the nucleoside structures was made on the basis of previous crystallographic works relative to TM, 3'OATM, 3'5'DOATM and Ba(TMP).6H2O. The crystal structures of the other compounds reported here are, as yet, unknown. However, their nucleoside structures were inferred from the position of the phosphoester stretching band. The results show that C(2')-endo-anti, C(3')-endo-anti and C(2')-endo/C(3')-exo-anti puckers generate marker bands useful to characterize and titrate these thymidine nucleoside conformations. The furanose sugar puckering of the C(2')-endo-anti geometry has been suggested to account for the enhanced activity of thymidine derivatives against human immunodeficiency virus-type 1. A Raman spectroscopic method is described for the determination of this structure in thymidine nucleosides and nucleotides.

Crystallization↗