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Biomedical subjects

M Alvarez

Publications and source records attributed to M Alvarez.

At least 271 records · Page 15Linked to original sources
PubMed1994

The effect of placenta previa on blood loss in second-trimester pregnancy termination.

OBJECTIVE: To determine whether placenta previa increases bleeding during second-trimester pregnancy termination. METHODS: The records of 131 consecutive women undergoing elective pregnancy termination at 13-24 weeks' gestation were reviewed and divided into those with and without placenta previa based on an ultrasound examination before the procedure. These two groups were then compared for differences in maternal characteristics, estimated blood loss, operative time, infection, and hospital admission. RESULTS: Twenty-three of 131 women (17.6%) had placenta previa. Sixty-seven percent of the previa patients smoked, versus 37% in the control group, a statistically significant difference. A statistical difference was noted with respect to placenta previa in intraoperative blood loss (P < .05), but not operative time, time to discharge, infection, hemorrhage, or other complications. CONCLUSION: Second-trimester pregnancy terminations in the presence of placenta previa are associated with a higher estimated blood loss, but no apparent increase in abortion-related infection, postoperative transfusion requirements, hysterectomy, or other complications.

Abortion, Therapeutic↗
PubMed1994

[Middle lobe syndrome].

Middle lobe syndrome (MLS) or atelectasis syndrome can affect any pulmonary lobe but occurs more frequently in the right middle lobe. Only 15 per cent of the reported cases are children. We report two cases of MLS in two boys of 4 and 12 years of age who were referred to our institution because they had suffered from recurrent pneumonies of the right middle lobe for ten months and six years respectively. We performed chest radiographs, computed tomography scanning, ventilation-perfusion scintigraphy and flexible bronchoscopy. The evolution in both cases to an atelectasic middle lobe with pulmonary shrinkage and lack of perfusion was the indication to lobectomy. Histological examination showed a bronchial obstructive process in the young patient and a chronic non specific inflammation of the pulmonary parenchyma in both. The resection brought about a cure. The identification of MLS is usually a late diagnosis. Thus, if atelectasis persists after an adequate medical therapy, resection of the lobe is indicated.

Child↗
PubMed1994

Risk factors for severe preeclampsia.

OBJECTIVE: To identify risk factors associated with severe preeclampsia and to determine whether these factors are similar in nulliparous and multiparous patients. METHODS: Patients whose pregnancies were complicated by severe preeclampsia (n = 70) were compared retrospectively to 18,964 non-preeclamptic controls. Information on maternal demographic factors; medical, obstetric, and family histories; and neonatal outcome was retrieved and analyzed by univariate and multivariate analysis. RESULTS: By logistic regression, the only risk factors associated with the development of severe preeclampsia were severe obesity in all patients (adjusted odds ratio 3.5, 95% confidence interval [CI] 1.68-7.46) and a history of preeclampsia in multiparous patients (adjusted odds ratio 7.2, 95% CI 2.74-18.74). CONCLUSION: Severe obesity and a history of preeclampsia are the only maternal risk factors identified for the development of severe preeclampsia.

Adult↗
PubMed1994

[Inhibition of the multiplication of a Coxsackie A9 strain isolated from a patient with epidemic neuropathy by the interferons alfa and gamma].

We present the results of the in vitro action of alpha and gamma interferons and of Intacglobin and Igegam against the 47/93/IPK (Coxsackie A9) strain isolated from the cerebrospinal fluid of a patient with epidemic neuropathy. The in vitro studies showed that the two interferons inhibited the replication of this agent; they also showed the presence of antibodies to it in the Intacglobin and Igegam. The results attained demonstrated that the use of these compounds could be effective for the treatment of this entity.

Animals↗
PubMed1994

[Design of a curve model for the detection of human immunoglobulin G against herpes simplex virus in ultramicroELISA from a single serum dilution].

The use of a curve model in the application of a ultramicroELISA technique for the detection of human immunoglobulin G against herpes simplex virus is reported. Based on end point titration (linear regression) of 100 initial sera, 51 of these, with r2 > 0.98, were selected, and 4 curve models were elaborated to relate the natural fluorescence logarithm for 4 dilutions with the previously determined natural end point titration logarithm. The curve corresponding to the 1:40 (r2 = 0.9645) was selected to evaluate 39 additional serum samples whose approximate titration was known through the graphic design of the 4 dilutions. An 89% coincidence was found regarding the latter. Divergence of the other 11% was due to the lack of accuracy of the graphic method in the points near the cutline.

Algorithms↗
PubMed1993

Walker-Warburg syndrome: prenatal ultrasound findings.

The prenatal sonographic findings in a case of Walker-Warburg syndrome are described. The patient was not at risk for this condition. Ultrasound examination at 34 weeks' gestation revealed hydrocephaly, Dandy-Walker anomaly, and striking ocular abnormalities. From a review of the literature it appears that while intracranial abnormalities can lead to the diagnosis in cases at risk for this syndrome, ocular abnormalities are rather characteristic for this syndrome and they should be searched for in every case of hydrocephaly or encephalocele.

Abnormalities, Multiple↗
PubMed1993

Molecular epidemiology of two genes encoding 3-N-aminoglycoside acetyltransferases AAC(3)I and AAC(3)II among gram-negative bacteria from a Spanish hospital.

The molecular epidemiology of the aacC1 and aacC2 genes, encoding 3-N-aminoglycoside acetyltransferases AAC(3)I and AAC(3)II, respectively, was studied by DNA-DNA hybridization. The sample included 315 gentamicin-resistant Gram-negative bacilli collected over a six-month period from patients attending a Spanish Hospital. The aminoglycoside resistance phenotype of these strains was also determined. The aacC1 probe hybridized with 39 strains, the aacC2 probe with 146 strains and both probes hybridized with 26 strains. The aacC1 gene was most frequently detected in Pseudomonas aeruginosa whereas the aacC2 gene was most frequently detected in enterobacteria and Acinetobacter spp. Strains harbouring aacC genes were isolated from both in- and outpatients with different infectious diseases, mainly urinary tract infections. As inferred from the results of Southern hybridization, both genes showed a wide horizontal dispersion among plasmids and bacteria.

Acetyltransferases↗
PubMed1993

The presence of cervical and vaginal fetal fibronectin predicts preterm delivery in an inner-city obstetric population.

OBJECTIVE: It has previously been shown that fibronectin bearing a specific oncofetal domain is present at the chorionic-decidual interface and that its release into cervical and vaginal secretions accurately predicts preterm delivery in patients with uterine contractions. This study examines whether serial assessment of cervical and vaginal fetal fibronectin allows for the prediction of preterm delivery in symptom-free patients derived from an inner-city, general obstetric population. STUDY DESIGN: Cervical and vaginal samples were obtained from 429 consenting patients who received routine prenatal care between 24 and 37 weeks' gestation. A sensitive immunoassay was used to quantitate cervical and vaginal fetal fibronectin levels, and clinicians were blinded to fetal fibronectin results. Post hoc receiver operating characteristic curve analysis was used to determine which sample site (cervical or vaginal), fetal fibronectin concentration, and number of consecutive positive samples optimized screening efficacy. Logistic regression was employed to determine whether fetal fibronectin was an independent predictor of preterm delivery. RESULTS: The spontaneous preterm delivery rate was 11% (49/429). Among the 326 patients sampled within 28 days of delivery, receiver operating characteristic curve analysis indicated that the presence of a single cervical fetal fibronectin value > 60 ng/ml between 24 and 36 weeks' gestation predicted preterm delivery with a sensitivity of 73%, a specificity of 72%, and positive and negative predictive values of 25% and 95%, respectively. A vaginal fetal fibronectin value > 50 ng/ml predicted preterm delivery with a sensitivity of 68%, a specificity of 80%, and positive and negative predictive values of 30% and 95%, respectively. Cervical and vaginal fetal fibronectin predicted preterm deliveries resulting from both membrane rupture and preterm labor with intact membranes. A positive fetal fibronectin result preceded preterm delivery by 3.4 (+/- 3.2) weeks. Stepwise logistic regression demonstrated that cervical and vaginal fetal fibronectin levels were independent predictors of preterm delivery with adjusted odds ratios of 8.9 (95% confidence interval 3.6 to 22.1) and 6.0 (95% confidence interval 2.6 to 13.7), respectively. CONCLUSIONS: Among patients undergoing monthly cervical and vaginal sampling between 24 and 36 weeks' gestation, the presence of fetal fibronectin is a sensitive and specific predictor of preterm delivery.

Cervix Uteri↗
PubMed1993

Double-blind; placebo-controlled trial of piperacillin prophylaxis in preterm membrane rupture.

OBJECTIVE: We attempted to test whether antibiotic therapy prolongs pregnancy in preterm premature rupture of membranes, because preterm premature rupture of membranes is frequently associated with chorionic-decidual infection. STUDY DESIGN: Women with preterm premature rupture of membranes and a singleton gestation at 24 to 34 completed weeks were randomized to receive either piperacillin 3 gm or placebo intravenously every 6 hours for 72 hours and were managed conservatively until spontaneous delivery, chorioamnionitis, or fetal distress. RESULTS: Between January 1987 and January 1992, a total of 75 patients were randomized to receive piperacillin (n = 38) or placebo (n = 37). There were no differences between the piperacillin group and the placebo group in mean gestational age at randomization (30.2 +/- 3 vs 30.3 +/- 2.9 weeks). However, a greater number of patients had pregnancy prolonged beyond 7 days (42.1% vs 10.8% p = 0.005) and the mean latency period was significantly prolonged (11.4 +/- 18.8 vs 6.1 +/- 13.6 days, p = 0.001) in the piperacillin group compared with the control groups. CONCLUSIONS: Use of intravenous piperacillin for 72 hours in preterm premature rupture of membranes significantly prolongs the latency period between membrane rupture and delivery.

Adult↗
PubMed1993

The risk of second-trimester amniocentesis in twin gestations: a case-control study.

OBJECTIVE: Pregnancy outcomes in patients with twin pregnancy undergoing second-trimester amniocentesis for fetal karyotype assessment were compared in a case-control study with twin pregnancies undergoing routine ultrasonographic studies at similar gestational ages. STUDY DESIGN: All spontaneous and induced twin gestations that underwent ultrasonographic examination between 14 and 20 weeks were compiled for the period January 1987 through January 1992. Patients having undergone multifetal reduction or chorionic villous sampling and those with fetal anatomic or chromosomal anomalies, discordant growth (> 20%), death, or a monoamniotic sac detected at ultrasonography were excluded. RESULTS: The mean (+/- SD) maternal age was significantly higher among the 101 cases than among the 108 controls (35.2 +/- 3.5 vs 30.4 +/- 5.3 years, respectively; p < 0.01). No differences were noted in gravidity, parity, number of prior spontaneous losses, or gestational age at ultrasonography between the two groups. The fetal loss rate was similar among cases and controls (seven of 202 [3.5%] vs seven of 216 [3.2%], relative risk 1.07, 95% confidence intervals 0.3 to 3.5). No losses occurred within 3 weeks of the procedure. Gestational age at delivery, birth weight, mean Apgar scores at 1 and 5 minutes, and length of neonatal stay were not significantly different between cases and controls. CONCLUSIONS: Second-trimester amniocentesis in twin pregnancies is apparently not associated with excess pregnancy loss.

Abortion, Spontaneous↗
PubMed1993

Is fetal blood sampling associated with increased beta-endorphin release into the fetal circulation?

This study was conducted to determine whether fetal blood sampling during the second trimester is associated with changes in circulating fetal beta-endorphin (BE) concentrations. We measured BE concentrations in 68 paired fetal and maternal blood samples obtained between 18 and 28 weeks' gestation. Patients were divided into a control group (n = 50), if the fetal blood samples were obtained by a single umbilical cord puncture, or multiple insertion group (n = 18), if multiple cord punctures were required to obtain a sample. The mean (+/- SE) fetal BE value for the multiple insertion group was significantly higher than BE levels from the control group (771.2 +/- 79.2 pg/ml versus 107.1 +/- 11.7 pg/ml; p < 0.001]. This elevation did not appear to be related to acidosis, since no differences in fetal umbilical pH were observed between the two groups. Fetal BE levels from the control but not from the multiple insertion group significantly correlated with maternal values (Spearman rank r = 0.59; p < 0.001 vs r = -0.08; p > 0.5). In neither group did fetal BE levels correlate with gestational age. These findings indicate that multiple cord punctures at the time of fetal blood sampling are associated with significant increases in BE release. Furthermore, although a maternal or placental contribution to steady state circulating fetal BE cannot be excluded, it would seem that the fetus itself is the primary source of elevated circulating BE levels following multiple cord punctures.

Cordocentesis↗
PubMed1993

Obstetric hemorrhage: prophylactic and emergency arterial catheterization and embolotherapy.

The role of arterial catheterization and embolotherapy was evaluated in 18 patients with postpartum hemorrhage or a risk of hemorrhage. Nine patients underwent emergency arterial catheterization for unanticipated postpartum hemorrhage due to uterine and vaginal tears and/or placental abnormalities. Bleeding was controlled with embolization with gelatin sponge in eight patients, while bleeding in one patient stopped spontaneously during angiography. Nine patients underwent prophylactic arterial catheterization before cesarean section or for abnormalities associated with risk of hemorrhage. Two subsequently underwent embolization before surgery, and embolization in two others was performed intraoperatively in response to serious bleeding. Bleeding in the other five was controlled by the usual surgical means. Arterial embolotherapy in these patients was an effective means of controlling postpartum hemorrhage. Prophylactic arterial catheterization has a role in patients with an increased risk for obstetric hemorrhage.

Angiography↗
PubMed1993

Progestational regulation of human endometrial stromal cell tissue factor expression during decidualization.

Decidualized endometrial stromal cells from mid- to late secretory phase and decidual cells from gestational human endometrium displayed prominent immunohistochemical staining for tissue factor, a primary initiator of hemostasis. Consistent with the regulation by progesterone of the decidualization process in vivo, medroxy-progesterone acetate elevated the tissue factor content of primary stromal cell cultures 8-fold over basal values. This increase paralleled the release of immunoreactive PRL, a marker of decidualization. The induced, as well as basal, tissue factor displayed full functional activity and the expected electrophoretic mobility (46 kilodaltons). Moreover, Northern analysis of RNA from cultured stromal cells indicated that medroxyprogesterone acetate increased tissue factor mRNA levels approximately 10-fold relative to control levels. In contrast, cultured stromal cell tissue factor protein content and mRNA levels were unaffected by exogenous estradiol. These findings indicate that enhancement of endometrial stromal cell tissue factor content is associated with progesterone induction of the decidualization process. In humans, trophoblastic invasion of the endometrial vasculature during blastocyst implantation risks hemorrhage. Therefore, increases in perivascular decidual cell tissue factor expression could serve to promote periimplantational endometrial hemostasis.

Blotting, Northern↗
PubMed1993

Steroid-modulated stromal cell tissue factor expression: a model for the regulation of endometrial hemostasis and menstruation.

This study examined steroidal regulation of tissue factor expression by cultured endometrial stromal cells. Confluent stromal cell cultures derived from cycling human endometria were exposed to vehicle control, 10(-8) mol/L estradiol (E2), 10(-8)-10(-6) mol/L medroxyprogesterone acetate (MPA), or both E2 and MPA for 2-24 days in serum-containing medium. The progestin enhanced immunoreactive and functionally active stromal cell tissue factor content, achieving peak effects by 8-12 days of culture. Although E2 alone was ineffective, it augmented MPA-enhanced tissue factor content by 8 days of culture, with continued increases beyond 20 days. Dose-dependent effects on tissue factor protein content were observed between 10(-8)-10(-6) mol/L MPA added alone or together with E2. The content of tissue factor mRNA was also increased by MPA and synergistically increased by E2 plus MPA. Similar steroidal effects on stromal cell tissue factor protein and mRNA content were observed using a defined medium. After optimal induction of tissue factor expression by E2 plus MPA, removal of these steroids reduced levels of stromal cell tissue factor mRNA and protein, with virtually complete reversal by day 7 of withdrawal. These time-course and dose-response relationships establish in vitro conditions with which to dissect factors controlling endometrial hemostasis, whereas the observed effects of steroid withdrawal establish a novel model for the study of mechanisms regulating normal and abnormal uterine bleeding.

Cells, Cultured↗
PubMed1993

Reprogramming of nucleolar gene expression during the acclimatization of the carp.

During seasonal acclimatization of eurythermal fish, the nucleolus of the hepatocyte undergoes ultrastructural reprogramming. In winter acclimatized carp, the nucleolar components are segregated, a condition that suggests a decreased transcription of rRNA. The same nucleolar reorganization was observed when pituitary cells from winter- and summer-acclimatized carp were examined. In situ analyses of nucleolar RNA revealed a marked lowering of RNA content in the segregated nucleoli. Accordingly, in vitro synthesis of RNA was shown to be significantly lower in pituitary tissue from cold-acclimatized fish where precursor accumulated. Conversely, in pituitary tissue from summer-adapted fish the rate and extent of synthesis and of rRNA processing was notably higher. The involvement of pre-rRNA processing events during seasonal acclimatization was corroborated by the strong differences of U3 RNA content detected by in situ hybridization in pituitary cells from summer- and winter-fish. When RNA polymerase I activity from both acclimatized states were assayed, no differences were detected. Thus, it appears that in fish RNA polymerase I itself does not play an important role in the control of nucleolar gene expression and the nucleolar gene expression reprogramming that the seasonal rearrangement represents might involve, among the many nucleolar-specific proteins, transcription factors.

Acclimatization↗