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Biomedical subjects

A Garcia

Publications and source records attributed to A Garcia.

At least 127 records · Page 7Linked to original sources
PubMed1998

Effects of repeated ultrasound-guided transvaginal follicular aspiration on bovine oocyte recovery and subsequent follicular development.

We wished to compare cumulus oocyte complex (COC) recovery and follicle development after single and repeated ultrasound-guided transvaginal follicle aspiration (aspiration). Aspirations were performed in Holstein-Friesian heifers every once weekly (every 7 d; n = 12) or twice weekly (every 3 or 4 d; n = 6) starting on Days 3 or 4 of the estrous cycle (estrus = Day 0) and continuing for 4 wk. During each session, all visible follicles > 2 mm were aspirated using an 7.5 MHz transducer to guide an 18 ga x 60 cm single lumen needle and applying 50 mm Hg vacuum which generated 25 mL/min. The COC's harvested from each follicle were counted and classified into 4 categories. Post-aspiration follicle wave emergence was traced by daily ultrasound examinations. A total of 1410 follicles were aspirated during 96 sessions, yielding 632 (45%)oocytes. There was no difference in average COC/follicle recovered between the single vs the repeated aspiration treatment. However, ovaries of heifers subjected to two aspirations per week yielded more follicles (17.2 +/- 5.7 vs 12.4 +/- 6.1; P < 0.01) and COC's (7.7 +/- 4.5 vs 5.4 +/- 3.7; P < 0.01) per session than those subjected to a single aspiration. Ovaries of heifers subjected to twice weekly aspirations at 4-d intervals resulted in a higher recovery rate (51.1 vs 38.6%), yielded more COC's (9.3 +/- 4.7 vs 6.2 +/- 3.8) and a higher number of viable COC's recovered per session (7.6 +/- 3.8 vs 5.2 +/- 3.3) than those aspirated every 3 d, all P < 0.01. Aspiration-induced follicle waves were indicated by an increased number of follicle > or = 4 mm seen within 2 d of the procedure. We conclude that follicle aspiration appears to induce and synchronize follicle waves, and when it is done twice a week it is associated with higher number of harvestable follicles and more oocytes recovered than when done once a week. These results can be attributed to the aspiration of a newly recruited pull of follicles 3 or 4 d after the first aspiration and before the establishment of follicular dominance and regression of subordinate follicles.

Animals↗
PubMed1998

Metallothionein-I+II induction by zinc and copper in primary cultures of rat microglia.

Metallothioneins (MTs) are a family of low molecular weight proteins which in rodents comprise four isoforms (MT-I to -IV). MT-I+II are widely expressed isoforms which are highly inducible by factors such as heavy metals and a number of hormones. The expression of these isoforms in the brain has been regarded as basically astrocytic, and to a lower extent, neuronal. We, however, demonstrate in this report, by radioimmunoassay and immunocytochemistry, that MT-I+II are expressed in primary cultures of rat microglia and that, furthermore, they are inducible by zinc and copper. Thus all major brain cell types may express the MT-I+II isoforms and respond with increased protein levels to physiological stimuli such as increased extracellular zinc and copper content. In contrast, microglia MT-I+II levels are not affected by either the glucocorticoid dexamethasone or the cytokine IL-1 under the experimental conditions.

Animals↗
PubMed1998

Preservative-free lidocaine 1% anterior chamber irrigation as an adjunct to topical anesthesia.

PURPOSE: To evaluate the effect on the central corneal endothelium of anterior chamber irrigation with preservative-free lidocaine 1% as an adjunct to topical anesthesia during phacoemulsification. SETTING: Department of Ophthalmology, Hospital Capuchos, Lisbon, Portugal. METHODS: This prospective, randomized controlled study comprised 59 eyes. Thirty-one eyes had phacoemulsification (in-the-bag cracking technique) under topical anesthesia with anterior chamber irrigation by preservative-free lidocaine 1%. Twenty-eight eyes having the same procedure but with local-regional anesthesia served as the control group. All eyes had preoperative and postoperative specular microscopy and computer-assisted morphometry. A Student's t-test was used for between-group comparison of the following parameters: patient age, central corneal endothelial cell loss, mean endothelial cell size variation, and phacoemulsification ultrasound time Follow-up was 4 weeks. RESULTS: The between-group differences in mean patient age and ultrasound time were not significant. The differences between groups in the endothelial cell parameters were also not significant. Mean postoperative endothelial cell loss was 3.59% +/- 2.79 (SD) in the topical anesthesia group and 4.37 +/- 2.00% in the control group. Mean variation in cell size was 3.71 +/- 1.57% and 3.79 +/- 1.07%, respectively. CONCLUSION: Intracameral infusion of preservative-free lidocaine 1% had no effect on the corneal endothelial cell loss rate or mean cell size variation in this short-term assessment.

Adjuvants, Anesthesia↗
PubMed1998

Gastric and duodenal ulcers during pregnancy.

The frequency, symptoms, and complication rate of peptic ulcer disease appear to decrease during pregnancy significantly. Clinicians, however, often have to treat dyspepsia or pyrosis of undetermined cause because the frequency of pyrosis increases during pregnancy. Physicians are reluctant to perform esophagogastroduodenoscopy (EGD) during pregnancy for pyrosis to reliably differentiate gastroesophageal reflux from peptic ulcer disease. Dyspepsia or pyrosis during pregnancy first should be treated with dietary and lifestyle changes, together with antacids or sucralfate. When symptoms persist, H2 receptor-antagonists are recommended. If symptoms continue and are severe despite these interventions, the patient should be evaluated for possible EGD or proton pump inhibitor therapy during the second or third trimester.

Diagnosis, Differential↗
PubMed1998

Effect of an elemental diet on the mechanical resistance and morphology of the colon in rats.

The aim of this study was to investigate the effect of an elemental diet (ED) on colonic morphology and mechanical resistance. Rats received either laboratory chow (control group; n=6) or oral total parenteral nutrition solution (ED group; n=6). After 14 d the colon was measured and weighed with and without the contents. Bursting pressure was determined in the right and left colon. Samples of these segments were examined histologically. Crypt depth and wall width (WW) were measured. All animals gained body weight. The bowels of ED-fed animals were shorter (23.7+/-1.6 versus 19.7+/-1.8 cm; P=0.003) and weighed less than the controls either with (10.3+/-0.8 versus 5.0+/-0.7g, P < 0.001) or without (4.9+/-0.9 versus 2.6+/-0.3 g; P < 0.001) feces. Bursting pressure was lower in animals receiving ED compared with controls (right colon: 250+/-30 versus 200+/-30 mm Hg; P=0.03; left colon: 195+/-22 versus 160+/-14 mm Hg; P=0.009). Crypt depth and WW were significantly shorter in the left colon in the ED group. Administration of ED promotes lack of mechanical resistance and atrophy of the colonic wall, especially in the left colon.

Animals↗
PubMed1998

Estrogens modulate bovine vascular endothelial cell permeability and HSP 25 expression concomitantly.

The atheroprotective properties of estrogens are supported by clinical data from postmenopausal women who use estrogen replacement therapy. However, the mechanisms mediating activity remain unknown, and it has been suggested that estrogens may help to modulate endothelial permeability to atherogenic lipoproteins. In these studies we used bovine vascular endothelial cells as an in vitro model to show that estrogens were able to regulate low-density lipoprotein transport and permeability of the endothelial monolayer. Macromolecular transport was observed to be a second-order polynomial function of estrogen concentration. Moreover, this regulation was correlated with expression of heat shock protein (HSP) 25, which is known to influence fluid phase pinocytosis and cytoskeleton remodeling, thus suggesting a role for HSP 25 in the estrogenic control of transcellular permeability of the endothelium monolayer.

Animals↗
PubMed1998

Genetic control of blood infection levels in human malaria: evidence for a complex genetic model.

There is now accumulating evidence for the involvement of genetic factors in the control of immune response against malaria. These arguments come from numerous animal models, from population studies showing associations of red blood cell genetic defects as well as HLA antigens with severe malaria, and from familial studies including a recent segregation analysis, which led to detection of a major gene effect predisposing to high infection levels. The heterogeneity and complexity of this genetic control is one of the main findings of these previous studies, and probably a major cause of the difficulty in developing an effective malaria vaccine. A segregation analysis of blood infection levels is performed here in 44 pedigrees living in the tropical rain forest of southern Cameroon and exposed to high vectorial transmission intensity. The results confirm the existence of complex genetic factors controlling blood infection levels in human malaria but are not consistent with the parent-offspring transmission of a single Mendelian gene. This study also shows the dramatic effect of age on infection levels and its interaction with a putative major gene suggesting that genetic related differences are much more important in children than in adults. Further genetic studies focused on children may help to identify the nature of the genetic factors involved in the expression of human malaria, by means of linkage analyses using both familial information and genetic markers.

Adolescent↗
PubMed1998

Epidemiologic characterization of American cutaneous leishmaniasis in an endemic region of eastern Venezuela.

The status of American cutaneous leishmaniasis was investigated from 1985 to 1991 to provide an epidemiologic characterization of the disease in Bergantin, a rural community in the northeastern part of Anzoátegui State, Venezuela. The study revealed the presence of the infection during the period analyzed, with an average incidence of 50.2 cases per 10,000 inhabitants and this number has increased 1.5 times during the last two years. Three villages where clinical cases had been recorded were selected for a comparison of their prevalence data. These villages comprise the human population in the high and low altitude limits of Bergantin. Immunologic assessment of the inhabitants used two different antigen preparations to examine responses to parasites associated with the cutaneous and visceral forms of the disease. The leishmanin skin test (LST) was used in a sample of 276 individuals (46.3% of the inhabitants) and resulted in an overall positivity of 16.7%. The percentage of LST positivity varied with age and sex, yet analysis of this response and the prevalence for each village reflected the specific characteristics of these localities. La Montaña, situated at 800 meters above sea level, had the highest prevalence (800 cases per 10,000 inhabitants) and the most positive LST response (21.2%) in comparison with the two other villages situated at a lower altitude (300 meters above sea level).

Endemic Diseases↗
PubMed1998

Linkage analysis of blood Plasmodium falciparum levels: interest of the 5q31-q33 chromosome region.

There is accumulating evidence for the involvement of genetic factors in the human response to malaria infection, mostly based on results obtained in studies of severe clinical malaria. The role of major gene(s) controlling blood parasitemia levels in human malaria has also been detected by means of segregation analysis. To confirm and to localize such gene(s), we performed a sib-pair linkage analysis investigating the role of five candidate chromosomal regions: 6p21 (HLA-tumor necrosis factor region), 2q13-q21 (genes coding for interleukin-1 alpha and beta), 14q11 (locus coding for the alpha chain of T cell antigen receptor), 7q35 (gene cluster for the beta subunit of T cell receptor), and 5q31-q33, which includes several candidate genes and was recently linked to a locus controlling infection levels by Schistosoma mansoni, denoted as SM1. The analysis was carried out on nine families from a southern Cameroon village, and the phenotype under study was blood infection levels with Plasmodium falciparum. No linkage was found with any of the four markers outside the 5q31-q33 region. A trend in favor of linkage was observed in the distal part of the 5q31-q33 region, especially with the marker D5S636 (P < 0.05 using the Monte Carlo P value), which was the marker that provided the highest evidence for linkage with SM1. These results suggest that a locus influencing P. falciparum levels in malaria could be located in the same genetic region as that containing SM1, indicating that the 5q31-q33 region may be critical in the control of different parasite infections.

Adolescent↗
PubMed1998

Factors influencing long-term primary cadaveric kidney transplantation--importance of functional renal mass versus avoidance of acute rejections--the Toronto Hospital experience 1985-1997.

1. The 5-year actuarial graft, patient and functional graft survival rates were analyzed in 743 consecutive primary cadaveric kidney transplants from The Toronto Hospital between January 1985-December 1997. 2. Recipient age > or = 55 years, male recipient sex, recipient diabetes mellitus, CIT > 36 hours and delayed graft function were found to significantly decrease patient survival. 3. Recipient age > or = 55 years, sensitization to HLA antigens (peak PRA > 50%), donor/recipient HLA antigen mismatches, CIT > 36 hours, delayed graft, function and 6-month SCr > 200 mumol/L were found to significantly decrease graft survival. 4. Acute rejection episodes had no significant impact on overall 5-year patient or graft survival. 5. The observation that serum creatinine > 200 mumol/L had a major adverse influence on long-term outcome reflects the importance of functional renal mass on graft survival.

Adult↗
PubMed1998

[Methylene blue in surgery of primary hyperparathyroidism].

Is surgery for primary hyperparathyroidism easier when methylene blue (MB) is given preoperatively? This retrospective study compares the durations of interventions for primary hyperparathyroidism carried out after i.v. MB administration to those when no MB was given. Over a period of 20 years (June 1976 to December 1996), 175 consecutive patients (56 men and 119 women, with ages ranging from 16 to 92, mean 59.6) were operated upon for primary hyperparathyrodism; 55 were operated before February 1986--the period when BM was introduced routinely, and 120 after. Thirty-two other patients were excluded from the study: 14 had had a previous cervicotomy and 18 another procedure in addition to the parathyroidectomy (usually on the thyroid gland), two conditions which prolonged the time devoted to parathyroid identification and excision. Preoperative calcemia averaged 2.97 mmol/L (2.34 to 4.59) and mean preoperative PTH was equal to 2.6 times the upper normal limit (0.5 to 24.1). Both groups were similar for as age, sex, preoperative calcium and PTH, and histologies. Methylene blue was administered intravenously (5 mg/kg diluted in 500 cc of 5% glucose) over a period of time of one hour starting two hours prior to surgery. All 175 procedures were performed by two surgeons and duration of surgery was recorded from the anesthesiologist's notes. There were 149 adenomas (85%), 24 hyperplasias (14%), a combination of both in two, and unspecified in two others. Except for a case of acute lower back pain synchronous to the injection of the dye (which was immediately stopped), MB was well tolerated. Mean duration for the 55 interventions performed without MB was 68 minutes (35 to 140, median 60), compared to 49 minutes for the 120 procedures carried out after MB had been given (20 to 155, median 45). Differences in operative, times were highly significant (p < 10(-6) and represented a gain of time of 27%. Surgery for primary hyperparathyroidism was significantly shorter when it was preceded by the administration of MB, a dye which facilitates the identification of pathologic parathyroid gland(s).

Adenoma↗
PubMed1998

Signs of glaucoma in rhesus monkeys from a restricted gene pool.

PURPOSE: To investigate the distribution of intraocular pressure (IOP) and cup properties in a colony of rhesus monkeys that has had no outside genetic input since 1938 (approximately 12 generations). This sample of sequestered monkeys is significantly larger than any previously reported. Comparisons are made with a sample of random-source monkeys to develop population estimates defining the limits of normalcy. METHODS: The IOP and cup/disc ratio estimates were collected from 701 eyes of 354 adult rhesus monkeys from the closed colony on Cayo Santiago, Puerto Rico. Results for IOP were compared with the normal rhesus IOP population distribution function calculated from an earlier sample of genetically heterogeneous rhesus. RESULTS: The mean +/- standard deviation IOP in the Cayo Santiago monkeys (15.8+/-3 mmHg) related well to the calculated "normal" rhesus distribution (14.5+/-2 mmHg) below and around the mean IOP only. Above the mean rhesus IOP, the samples from the Cayo monkeys were strongly skewed: 129 eyes had IOP more than two standard deviations above the normal mean IOP, and 54 eyes had IOP more than three standard deviations above the normal mean IOP. Cup/disc ratio estimations tended to cluster as higher values in the higher IOP quartiles. Some eyes with IOP below the mean had cup/disc ratios > 0.5. Values for IOP that were more than two standard deviations above the mean and cup/disc ratios > 0.4 were not uniformly distributed across social groupings, although incidence of high IOP was more than 25% in one group. CONCLUSION: After 12 generations with the same genetic pool, expression of ocular hypertension and large optic disc cups is high but not uniform.

Animals↗
PubMed1998

[Percutaneous suprapubic bladder lithotripsy].

The authors present a case of multiple bladder stones in a patient with severe ankylosis of the lower extremities, treated via percutaneous suprapubic approach. The suprapubic tract was created with Teflon-coated dilators and an Amplatz tube and the stones were fragmented with the nephroscope and a pneumatic lithotriptor. The simplicity of the procedure and the ease of the manoeuvre accelerated the stone fragmentation process while avoiding unnecessary trauma of the urethra.

Ankylosis↗
PubMed1997

The product of a gas6 splice variant allows the release of the domain responsible for Axl tyrosine kinase receptor activation.

The product of gas6 (Gas6) is a growth factor with high level of similarity to protein S and was identified as the ligand for Axl family of tyrosine kinase receptors. Gas6 contains an N-terminal gamma-carboxylated domain (Gla), four epidermal growth factor like domains and a large C-terminal D region. An alternative Gas6 spliced form (Gas6SV) having an additional 43 amino acids between fourth EFG like and D domain was characterised. Here we show data indicating that Gas6SV is specifically cleaved within the inserted sequence, thereby splitting the D domain from the remaining part of the protein. The resulting two proteolytic products of 36 kDa and 50 kDa were separated and the 50 kDa fragment corresponding to region D was shown to be responsible for Axl receptor activation. Furthermore a deletion mutant of Gas6 containing only the D domain was shown to similarly activate Axl receptor phosphorylation unequivocally demonstrating that D domain can act as a signalling molecule. The possible roles of the proteolytic processing of Gas6SV in the regulation of growth factor availability are discussed.

Alternative Splicing↗
PubMed1997

Protein phosphatase 2A is a critical regulator of protein kinase C zeta signaling targeted by SV40 small t to promote cell growth and NF-kappaB activation.

We have reported that inhibition of protein phosphatase 2A (PP2A) by expression of SV40 small t stimulates the mitogenic MAP kinase cascade. Here, we show that SV40 small t can substitute for tumor necrosis factor-alpha (TNF-alpha) or serum and stimulate atypical protein kinase C zeta (PKC zeta) activity, resulting in MEK activation, cell proliferation and NF-kappaB-dependent gene transcriptional activation in CV-1 and NIH 3T3 cells. These effects were abrogated by co-expression of kinase-deficient PKC zeta and inhibition of phosphatidylinositol 3-kinase p85alpha-p110 by wortmannin, LY294002 and a dominant-negative mutant of p85alpha. In contrast, expression of kinase-inactive ERK2 inhibited small t-dependent cell growth but was unable to abolish small t-induced NF-kappaB transactivation. Our results provide the first in vivo evidence for a critical regulatory role of PP2A in bifunctional PKC zeta signaling pathways controlled by phosphatidylinositol 3-kinase. Constitutive activation of PKC zeta and NF-kappaB following inhibition of PP2A supports new mechanisms by which SV40 small t promotes cell growth and transformation. By establishing PP2A as a key player in the response of cells to growth factors and stress signals like TNF-alpha, our findings could explain why PP2A is a primary target utilized during SV40 infection to alter cellular behavior.

3T3 Cells↗
PubMed1997

Bovine ultrasound-guided transvaginal amniocentesis.

Recent interest and research activities in ultrasound-guided transvaginal amniocentesis have contributed greatly to the development of a reliable technique, particularly with respect to a reduction in fetal loss after the puncture procedure. Several investigators have reported a variety of techniques for the collection of bovine fetal fluids at different stages of pregnancy; however, thus far, a high incidence of fetal loss has occurred as a consequence of the aspiration procedure. This manuscript describes the technical aspects of a safe and reliable ultrasound-guided transvaginal method of amniotic fluid collection from heifers (n = 93) with Day 79 to 90 bovine conceptuses using a very fine aspiration needle. Using this approach, collection of amniotic fluid samples was successful in 88 out of 93 (94.6 %) attempts, and no complications or pregnancy losses were recorded as a consequence of the procedure. The results reported here suggest that the incidence of spontaneous fetal loss associated with this transvaginal amniocentesis procedure is very satisfactory and could be the method of choice for the collection of fetal fluids in embryo transfer programs.

Journal Article↗