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Biomedical subjects

J E Garcia

Publications and source records attributed to J E Garcia.

At least 19 recordsLinked to original sources
PubMed2006

Genetic diversity in wild (Sus scrofa scrofa) and domestic (Sus scrofa domestica) pigs and their hybrids based on polymorphism of a fragment of the D-loop region in the mitochondrial DNA.

We examined the variation in mitochondrial DNA by sequencing the D-loop region in wild and domestic (large-white breed) pigs, in hybrids between domestic and wild pigs, and in Monteiro pigs. A D-loop fragment of approximately 330 bp was amplified by PCR. Sequencing of DNA amplicons identified haplotypes previously described as European and Asian types. Monteiro pigs and wild pigs had European haplotypes and domestic pigs had both European and Asian haplotypes.

Animals↗
PubMed2005

Identification of microsatellite DNA markers for the giant anteater Myrmecophaga tridactyla.

The giant anteater (Myrmecophaga tridactyla) is found from Belize and Guatemala to Paraguay and Argentina. Its conservation status is considered vulnerable by IUCN. Here we report the isolation and characterization of six microsatellite loci. Positive loci for (GT)(n) were isolated using a magnetic bead hybridization selection protocol. The number of alleles per locus as well as the heterozygosity and PCR conditions are described. These loci will be useful for studying population structure, genetic diversity, and paternity in M. tridactyla wild populations.

Animals↗
PubMed2005

An oocyte donation protocol using the GnRH antagonist ganirelix acetate, does not compromise embryo quality and is associated with high pregnancy rates.

PURPOSE: To evaluate the effect of the GnRH antagonist, ganirelix acetate, on oocyte quality. METHODS: Stimulation characteristics, implantation rates and clinical pregnancy rates were compared between 29 oocyte donors 21-31 years of age who underwent 31 cycles of ovarian stimulation with gonadotropins and ganirelix acetate, and 36 infertile couples of similar age range who underwent 51 cycles of ovarian stimulation using the same protocol. RESULTS: A significantly lower number of embryos were transferred in the donor/recipient group as compared to the infertile group (2.32+/-0.54 vs. 2.82+/-0.71, P<0.05). In contrast, implantation and clinical pregnancy rates per transfer, were significantly higher in the donor/recipient group (38.1% vs. 10.4%, P<0.01) and (61.3% vs. 23.1%, P<0.05) respectively, as compared to the infertile group. CONCLUSIONS: Incorporation of ganirelix acetate for pituitary suppression in stimulation protocols for oocyte donation is associated with high pregnancy rates suggesting that ganirelix acetate does not exert an adverse effect on oocyte or embryo quality.

Adult↗
PubMed2005

Genetic structure of Blastocerus dichotomus populations in the Parana River basin (Brazil) based on protein variability.

The population structure of 147 marsh deer (Blastocerus dichotomus) from three areas in the Paraná River basin, Brazil, was studied by observing protein polymorphism at 17 loci. Six loci were polymorphic and 11 monomorphic. The proportion of polymorphic loci (P) was 35.29% and the average heterozygosity (H) was 6.31%. Wright's FST indicated that only 4.9% of the total variation in allelic frequencies was due to genetic differences between the three groups. The high value of F(IS) (0.246) indicated inbreeding in the marsh deer. Genetic distance values (D = 0.014-0.051) showed little divergence between the three areas. We suggest that probable mechanisms accounting for the genetic structure are female phylopatry and polygyny and also that inbreeding has resulted from decreasing areas of wetland leading to isolation, overhunting, and diseases transmitted by cattle.

Animals↗
PubMed2002

Ticks associated with armadillo (Euphractus sexcinctus) and anteater (Myrmecophaga tridactyla) of Emas National Park, State of Goias, Brazil.

This study was conducted in October 1998 and November 1999 in the Emas National Park (131,868 ha), a savanna-type cerrado region situated in the far south of Goias State, Brazil, near the geographic center of South America (15 degrees -23 degrees S; 45 degrees -55 degrees W). Animals were captured with the aid of nets and anesthetized (15 mg/kg ketamine + 1 mg/kg xylasine) in order to collect ticks for identification and to establish laboratory colonies. They included giant anteaters (Myrmecophaga tridactyla) (n = 4) and yellow armadillos (Euphractus sexcinctus) (n = 6). Free-living ticks (larvae, nymphs, and adults) were collected from the field by using a 1 x 2-m flannel cloth. Free-living ticks were identified as Amblyomma sp., A. cajennense, and A. triste. Adult ticks collected from anteaters were identified as Amblyomma cajennense and A. nodosum and from armadillos as A. pseudoconcolor and A. nodosum. The relevance of these host-tick relationships to possible mechanisms underlying emergence of tick-borne pathogens of importance to public health is discussed.

Animals↗
PubMed2001

Plasmodium falciparum acid basic repeat antigen (ABRA) peptides: erythrocyte binding and biological activity.

Non overlapping 20-mer peptides, covering the complete sequence of acid basic repeat antigen (ABRA) of Plasmodium falciparum, were synthesised and tested in binding assays to erythrocytes. Five peptides localised in the N-terminal region coded 2148 (121LQSHKKLIKALKKNIESYQN(140)), 2149 (141KKHLIYKNKSYNPLLLSCVK(160)), 2150 (161KMNMLKENVDYIQKNQNLFK(180)), 2152 (201YKSQGHKKETSQNQNENNDN(220)) and 2153 (221QKYQEVNDEDDVNDEEDTND(240)) specifically bind to erythrocytes. These peptides bind independently of the peptide and erythrocyte charge, with high affinity (Kd between 70 and 180 nM) and the hydrophobic interaction is important for this binding ( approximately 30% hydrophobic critical residues). These results allow us define a specific erythrocyte binding region (residues 121-240), which may bound to at least three different binding sites on erythrocytes. Peptide 2153 shares the underlined sequence 221QKYQEVNDEDDVNDEEDTND(240) with an earlier 18-mer peptide recognised by human exposed sera. Peptides number 2148 and 2149 in vitro inhibit erythrocyte invasion by merozoites. We found that 2149 peptide and some of its glycine analogues show specific haemolytic and/or antimicrobial activity. We discuss a possible role of ABRA or its regions in the merozoite invasion of erythrocyte.

Amino Acid Sequence↗
PubMed2001

Plasmodium falciparum circumsporozoite (CS) protein peptides specifically bind to HepG2 cells.

Hepatocyte invasion by malaria parasites is mediated by specific molecular interactions. Several lines of evidence suggest the importance of the surface plasmodial circumsporozoite (CS) protein in the sporozoite invasion of hepatocytes. Identification of the sequences involved in binding to hepatocytes is an important step towards understanding the structural basis for the sporozoite-hepatocyte interaction. In this study, binding assays between Plasmodium falciparum CS peptides and HepG2 cells were performed. Fifteen overlapping residue 20 mer long peptides, spanning the entire CS sequence, were tested in HepG2 cell binding assays. Five High Binding Activity Peptides (HBAPs) to HepG2 cells were identified: 4593, (NANPNANPNANP); 4383, (NSRSLGENDDGNNEDNEKLR); 4388, (GNGQGHNMPNDPNRNVDENA); 4389, (HNMPNDPNRNVDENANANSA) and 4390, (DPNRNVDENANANSAVKNNN). The HBAP HepG2 interaction is independent of charge and amino-acid composition, but sequence dependent. Four HBAPs (4383, 4388, 4389 and 4390) are bound with similar affinity to a 50 kDa molecule. These HBAPs define three Hepatocyte Binding Sequences (HBSs): HBS-1, located between residues 68 and 87 (HBAP 4383); HBS-11, the repeat NANP region (HBAP 4593), for which anti repeat antibodies are able to specifically inhibit sporozoite invasion of hepatocytes have been reported; and HBS-111, between residues 286 and 315 (HBAPs 4388, 4388 and 4390), respectively. Interestingly, HBS 111 carries two earlier-reported B-epitopes (underlined) in peptides 4388, 4389 and 4390 (GNGQGHNMPNDPNRNVD ENANANSAVKNN) in its sequence. The HBSs reported here show lesser interspecie-variability than the entire protein in species invading the same kind of hepatic cells. This data supports these HBSs' important role in CS-protein function; they could be used as ligand by the sporozoite to invade hepatic cells.

Amino Acid Sequence↗
PubMed2000

Effect of cyclosporin A on inflammatory cytokine production by U937 monocyte-like cells.

Cyclosporin A (CsA) is an immunosuppresor drug that has been used in the treatment of several types of inflammatory diseases. In some of them the inhibition of T-lymphocyte activation does not suitably account for the observed beneficial effect, suggesting that CsA could act on other types of cells. The present study was undertaken to determine the effect of CsA on inflammatory cytokine secretion by U937 monocyte cells. Undifferentiated and dimethylsulfoxide (DMSO) differentiated U937 cells were incubated with different concentrations of CsA (200, 20 and 2 ng/mL) in the presence or absence of phorbol-myristate-acetate (PMA). Interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), IL-6 and IL-8 levels were measured in supernatants using specific enzyme-linked immunosorbent assays. At the highest concentration used (200 ng/mL) CsA decreased the basal and stimulated secretion of all the inflammatory cytokines studied in both undifferentiated and differentiated cells, with the only exception of PMA-stimulated IL-1 secretion by undifferentiated cells. However, only basal secretion of interleukin-8 in both undifferentiated and DMSO-differentiated U937 cells was significantly reduced by CsA at the highest concentration (200 ng/ mL). At therapeutic concentrations in vivo, CsA exerts a predominant effect on IL-8 secretion by human mononuclear phagocytes.

Cell Differentiation↗
PubMed1999

Exogenous luteinizing hormone (LH) increases estradiol response patterns in poor responders with low serum LH concentrations.

PURPOSE: Our purpose was to investigate whether the addition of exogenous leuteinizing hormone (LH) increases estradiol secretion in LH-depleted women undergoing controlled ovarian hyperstimulation (COH) with purified follicle stimulating hormone (FSH). METHODS: We carried out case series and retrospective analysis of midfollicular serum LH concentrations and estradiol response patterns in COH cycles. All patients initially received gonadotropins containing purified FSH. Human menopausal gonadotropin containing LH was added to poor responders with low midfollicular LH concentrations. RESULTS: The addition of exogenous LH to the COH regimen significantly increased estradiol secretion in poor responders with low midfollicular endogenous LH concentrations. This was confirmed statistically by an average change in the slope of the estradiol patterns from 27.54 to 85.49 after the addition of exogenous LH. Furthermore, patients with midfollicular serum LH concentrations < 3.0 mIU/ml had significantly lower midfollicular and peak estradiol (E2) concentrations compared to patients with LH concentrations > or = 3.0 mIU/ml (352.3 and 2094.3 vs 855.6 and 3757.1 pg/ml, respectively). CONCLUSIONS: The addition of exogenous LH increases E2 response patterns in poor responders with low midfollicular serum LH concentrations. Low midfollicular serum LH concentrations are associated with significantly lower midfollicular and peak E2 concentrations.

Adult↗
PubMed1997

Successful in vitro maturation of human oocytes not exposed to human chorionic gonadotropin during ovulation induction, resulting in pregnancy.

OBJECTIVE: To report a case of successful in vitro maturation of human oocytes not exposed to hCG during ovulation induction, resulting in pregnancy after transfer of a frozen-thawed embryo resulting from intracytoplasmic sperm injection (ICSI) of the in vitro-matured human oocytes. DESIGN: Clinical study. SETTING: Hospital-based private IVF center. PATIENT(S): A couple with infertility due to severe oligospermia. INTERVENTION(S): Five immature oocytes were retrieved from a patient who failed to use hCG during ovarian stimulation and were cultured for 48 hours in B2 medium containing FSH and hCG. Five oocytes extruded the first polar body and underwent ICSI with frozen-thawed husband spermatozoa. MAIN OUTCOME MEASURE(S): In vitro maturation, fertilization after ICSI, embryo development, and pregnancy. RESULT(S): All five oocytes extruded the first polar body and were injected using ICSI. Three oocytes were fertilized, but two showed three pronuclei. The remainder, a two-pronuclei embryo subsequently cleaved and was cryopreserved. An ongoing pregnancy was obtained after-the transfer of this frozen-thawed embryo. CONCLUSION(S): Immature human oocytes at the germinal-vesicle stage that have not been exposed to hCG during ovarian stimulation can be matured in vitro and a normal pregnancy can result from ICSI of the in vitro-matured oocytes.

Adult↗
PubMed1997

High fertilization rate obtained after intracytoplasmic sperm injection with 100% nonmotile spermatozoa selected by using a simple modified hypo-osmotic swelling test.

OBJECTIVE: To report a high fertilization rate after intracytoplasmic sperm injection (ICSI) in patients with 100% nonmotile spermatozoa selected by a simple modified hypo-osmotic swelling test. DESIGN: Clinical study. SETTING: Hospital-based IVF center. PATIENT(S): Three couples with infertility due to asthenospermia. INTERVENTION(S): The hypo-osmotic swelling test with 150-mOsm NaCl solution was used to select viable spermatozoa before ICSI. Three patients provided semen samples and one of these three also had a testicular biopsy. MAIN OUTCOME MEASURE(S): Selection of viable spermatozoa using the hypo-osmotic swelling test with 150-mOsm NaCl solution for ICSI. RESULT(S): No motile spermatozoa were found in three ejaculated semen samples and one testicular biopsy. Fifty-seven metaphase-II oocytes were injected with hypo-osmotic swelling test-positive ejaculated or testicular spermatozoa. Fifty-five (96.5%) of these oocytes were intact after injection. Forty-two (76.4%) of 55 oocytes showed two pronuclei, and 40 of the 42 fertilized oocytes cleaved. One patient had all embryos cryopreserved because of the risk of hyperstimulation; two other patients had embryos transferred. One ongoing pregnancy resulted. CONCLUSION: This hypo-osmotic swelling test with 150-mOsm NaCl solution is a simple and efficient method for selection of viable spermatozoa. A high fertilization rate can be obtained using ICSI with viable spermatozoa selected by using this hypo-osmotic swelling test.

Cryopreservation↗
PubMed1997

Establishment of an optimal hypo-osmotic swelling test by examining single spermatozoa in four different hypo-osmotic solutions.

In order to find an optimal hypo-osmotic swelling test (HOST) and to identify viable sperm cells from patients with asthenozoospermia for intracytoplasmic sperm injection (ICSI), we tested single motile and non-motile spermatozoa in four hypo-osmotic solutions by micromanipulation. The four solutions were: A, H2O; B, 50 mOsm NaCl; C, 150 mOsm NaCl and D, 150 mOsm sodium citrate and fructose. Eosin Y staining was then carried out for evaluation of viability of the spermatozoa after HOST. Using motile spermatozoa, no statistical difference was found in HOST-positive spermatozoa between these four solutions. There were more viable sperm cells after HOST in solutions C and D, as noted by Eosin Y staining. After non-motile spermatozoa were incubated for 1 min in the four solutions, HOST with solution C gave the best results for identification of viable sperm cells compared to the other three solutions. When motile spermatozoa were incubated in solution C or solution D for 30 min, the result of HOST with solution C (10.8% dead spermatozoa) was superior to that of solution D (49.1% dead spermatozoa). In conclusion, the HOST protocol using 150 mOsm NaCl (solution C) for 1 min yielded the best results for selection of viable spermatozoa. This procedure should be used for selection of viable spermatozoa for ICSI in patients with 100% non-motile spermatozoa.

Cell Membrane↗
PubMed1997

Outcome of in-vitro culture of fresh and frozen-thawed human testicular spermatozoa.

The effect of in-vitro culture on the motility and morphology of fresh and frozen-thawed human testicular spermatozoa obtained from obstructive azoospermic patients and on the motility of testicular spermatozoa obtained from non-obstructive azoospermic patients was evaluated. The outcome of intracytoplasmic sperm injection (ICSI) with fresh and frozen-thawed human testicular spermatozoa was studied. The results showed that significant improvement of sperm morphology and motility was observed in culture of fresh (n = 17) and frozen-thawed (n = 15) testicular sperm samples obtained from patients with obstructive azoospermia. The motility of cultured testicular spermatozoa reached a peak at 72 h without the need for special media. In six of 20 samples obtained from patients with non-obstructive azoospermia, improvement of sperm motility was observed. When only non-motile testicular spermatozoa were cultured, they all remained non-motile (n = 9). In patients with obstructive azoospermia, fertilization rates of 80 and 81% were obtained using ICSI with fresh and frozen-thawed testicular spermatozoa respectively. Clinical pregnancies were observed in four out of nine patients with fresh testicular spermatozoa and two out of five patients after using frozen-thawed spermatozoa. When fresh testicular spermatozoa obtained from patients with non-obstructive azoospermia were used for ICSI, the fertilization rate was 68% and two out of seven patients achieved clinical pregnancies. In conclusion, the morphology and motility of fresh and frozen-thawed testicular spermatozoa in patients with obstructive azoospermia can be significantly improved after in-vitro culture. The outcome of in-vitro culture of testicular spermatozoa in patients with non-obstructive azoospermia is unpredictable. In-vitro culture of non-motile testicular spermatozoa is not successful so far. The outcome of ICSI with fresh and with frozen-thawed testicular spermatozoa was similar.

Adult↗
PubMed1996

A unique case of massive ascites before ovulation associated with gonadotropin therapy.

OBJECTIVE: To describe a unique case of massive ascites associated with gonadotropin therapy. DESIGN: Case report. SETTING: Patient in a hospital-based private IVF center. INTERVENTION(S): Ovulation induction with gonadotropins for subsequent IVF. RESULT(S): Ovulation induction with gonadotropins resulted in the accumulation, before ovulation, of 1,200 and 2,000 mL of peritoneal fluid in two consecutive cycles. The stimulation yielded four and six oocytes, respectively. CONCLUSION(S): Gonadotropin therapy can result in ascites before ovulation without an exaggerated ovarian response and without interfering with follicular development.

Adult↗
PubMed1996

Hydrosalpinx affects the implantation of previously cryopreserved embryos.

The presence of hydrosalpinx has been reported to negatively affect the pregnancy and implantation rate after in-vitro fertilization (IVF) with embryo transfer. Hydrosalpinges are able to enlarge during ovarian stimulation with a possible increased passage of tubal fluid into the endometrial cavity. We report the effect of hydrosalpinges during the transfer of previously cryopreserved/thawed embryos during a natural cycle. In all, 14 transfers in 0 patients with a sonographically-documented hydrosalpinx during the studied cycle (group I) were compared to 98 cycles in 74 patients with tubal disease but no such sonographic finding (group II). Both pregnancy and implantation rates were significantly lower in group I (7.14 versus 24.49% and 5.0 versus 10. 8% respectively). The presence of hydrosalpinx negatively affects pregnancy and implantation rates during natural cycles.

Adult↗