Biomedical subjects

M Hallak

Publications and source records attributed to M Hallak.

At least 73 records · Page 4Linked to original sources

PubMed1993

Fetal serum and amniotic fluid magnesium concentrations with maternal treatment.

OBJECTIVE: To determine the effect of maternal intravenous (IV) magnesium sulfate administration on fetal serum and amniotic fluid (AF) concentrations of magnesium. METHODS: Thirty-six patients underwent fetal blood sampling for prenatal diagnosis of one of several abnormal conditions. Fifteen subjects had uterine contractions at the time of funipuncture and received IV magnesium sulfate therapy to quiet the uterus before the procedure. Three groups of subjects were defined: 21 untreated controls, ten women who received magnesium treatment for 1 hour, and five who received it for 3 hours before fetal blood sampling. Magnesium concentrations in maternal and fetal serum and AF were compared among the three groups. RESULTS: Patients who received magnesium sulfate for 1 and 3 hours had significantly higher concentrations of serum magnesium (4.11 +/- 0.6 and 5.54 +/- 0.2 mg/dL, respectively) than untreated subjects (1.77 +/- 0.2 mg/dL) (P < .0001). Fetal serum magnesium concentrations were significantly higher in the 1- and 3-hour groups (2.48 +/- 0.1 and 4.44 +/- 0.2 mg/dL, respectively) than in controls (1.67 +/- 0.2 mg/dL) (P < .0001). The AF magnesium concentration was significantly increased only after 3 hours of elevated maternal magnesium levels (1.45 +/- 0.2 and 2.84 +/- 0.2 mg/dL in controls and 3-hour group, respectively; P < .0001). The correlation between maternal and fetal blood magnesium concentrations was highly significant (r = 0.89; P < .0001), as was the correlation between fetal serum and AF concentrations (r = 0.84; P < .0001). CONCLUSION: Magnesium levels increase in fetal serum within 1 hour and AF within 3 hours after maternal IV administration.

Adult↗

PubMed1992

Mullerian adenosarcoma of the uterus with sarcomatous overgrowth.

A case of mullerian adenosarcoma of the uterus with sarcomatous overgrowth is described. The patient was also found to have bilateral polycystic ovaries. This 25 year-old white female presented with irregular vaginal bleeding and was diagnosed as having mullerian adenosarcoma with sarcomatous overgrowth by dilatation, curettage, and biopsy. Total abdominal hysterectomy, bilateral salpingo-oophorectomy with lymph node sampling were performed.

Adult↗

PubMed1992

The smaller than expected first-trimester fetus is at increased risk for chromosome anomalies.

OBJECTIVE: Intrauterine growth retardation associated with fetal chromosome anomalies is usually documented on ultrasonography late in the second trimester. However, we believe and attempt to document here that the impact of aneuploidy on fetal growth is evident much earlier (i.e., the aneuploid fetus may appear smaller than dates on ultrasonography even in the first trimester). STUDY DESIGN: For the population referred to our center for chorionic villus sampling from January 1988 to July 1991, we compared gestational age as calculated from the last menstrual period to that derived from fetal size as measured by crown-rump length. A cutoff of 7 days was chosen to select the study group. The remainder of our chorionic villus sampling population in which fetal size was expected was used as controls. We also divided those chorionic villus sampling patients by when a fetal death was observed by size. RESULTS: In the study period 3194 chorionic villus sampling procedures were performed and in 277 (8.7%) fetal length was smaller than expected by at least 7 days. Sixty (1.9%) chromosome anomalies were diagnosed by first trimester chorionic villus sampling in the study period. The frequency of chromosome anomalies was 4.3% in the study group and 1.7% in controls (p < 0.004). The more aberrant the karyotype on "postmortem chorionic villus sampling," the greater the growth retardation tended to be. CONCLUSIONS: In our chorionic villus sampling population a fetal crown-rump length smaller than dates is associated with a significant increase in risk of chromosome anomalies. Moreover, the larger the size-dates discrepancy, the higher the possibility that the aneuploidy affecting that pregnancy is of the severe or lethal type.

Adult↗

PubMed1992

Peripheral magnesium sulfate enters the brain and increases the threshold for hippocampal seizures in rats.

OBJECTIVES: Our objectives were to determine whether magnesium sulfate crosses the blood-brain barrier and whether it has central anticonvulsant action. STUDY DESIGN: In experiment 1 34 female Long-Evans rats were divided into six groups: control (n = 7); single magnesium sulfate injection and evaluation after 20 minutes in 3 conditions: normal rats (n = 7), sham-operated animals (n = 5), and after electrical stimulation by hippocampal electrode (n = 5); single injection and evaluation after 2 hours (n = 5); and prolonged (2 hours) serum magnesium elevation (n = 5). Serum, cerebrospinal fluid, and specific brain areas were analyzed for magnesium concentrations. In experiment 2 threshold for electrical seizure was measured in eight rats before and after intraperitoneal injections of magnesium sulfate versus saline solution. RESULTS: In experiment 1 there was a significant correlation between blood and cerebrospinal fluid magnesium concentrations (r = 0.80, p < 0.0001). Magnesium concentrations were increased in the cortex and hippocampus, with the largest changes occurring after two hours of sustained serum magnesium concentrations (p < 0.01). Induction of hippocampal seizure activity resulted in further elevations in cerebrospinal fluid magnesium concentrations but did not change brain concentrations. In experiment 2 magnesium sulfate increased the electrical threshold required to induce seizures by 34% (p = 0.01). CONCLUSIONS: Magnesium sulfate enters the cerebrospinal fluid and brain and has a central anticonvulsant effect.

Animals↗

PubMed1992

Oligohydramnios and megacolon in a fetus with vesicorectal fistula and anal-urethral atresia: a case report.

Severe oligohydramnios and extremely dilated bowel filled with hyperechogenic material floating in fluid were the ultrasonographic findings in a fetus at 27 weeks' gestation. Vesicorectal communication and urethral-anal atresia permitted urine to empty into the colon, causing megacolon, oligohydramnios, and markedly increased intraabdominal pressure resulting in pulmonary hypoplasia.

Anal Canal↗

PubMed1992

The effect of tocolytic agents (indomethacin and terbutaline) on fetal breathing and body movements: a prospective, randomized, double-blind, placebo-controlled clinical trial.

OBJECTIVE: The null hypothesis of this study is that maternal administration of indomethacin or terbutaline will not affect fetal breathing and body movements. STUDY DESIGN: Thirty patients with a low-risk pregnancy, gestational age 26 to 32 weeks, and no signs of preterm labor were randomly assigned to receive either terbutaline (5 mg), indomethacin (50 mg), or a placebo. Ultrasonographic evaluation of fetal breathing and body movements was performed for 1 hour before and 1 hour after treatment. The total amount of time of fetal breathing and body movements in each group was subject to statistical analysis that included analysis of variance and covariance and a multiple comparison procedure. RESULTS: Indomethacin increased fetal breathing from 20.8 +/- 13.1 minutes to 42.2 +/- 14.8 minutes (p < 0.01), whereas terbutaline increased fetal breathing movements from 19.8 +/- 9.0 minutes to 35.2 +/- 12.4 minutes (p < 0.01). No significant treatment effect was detected on fetal body movements. CONCLUSION: Between 26 and 32 weeks' gestation, a single dosage of indomethacin or terbutaline increases fetal breathing movements by 103% and 78%, respectively.

Double-Blind Method↗

PubMed1992

Effects of induction of labor with prostaglandin E2 on fetal breathing and body movements: controlled, randomized, double-blind study.

OBJECTIVE: To evaluate the effects of prostaglandin (PG) E2, given for induction of labor at term, on fetal breathing and body movements. METHODS: Eighteen women with term pregnancies, mild gestational hypertension, intact membranes, and unripe cervices who were not in labor participated in this study. After a 60-minute baseline ultrasound examination of fetal chest and body movements, recorded on videotape, the patients were randomly assigned to either 3 mg intravaginal PGE2 tablets or controls (placebo intravaginal tablets). Following tablet insertion and a 3-hour observation time, a second 60-minute ultrasound recording of fetal movements was taped. The videotape recordings were interpreted according to the total amount of time occupied by fetal body movements and fetal breathing movements. RESULTS: There was a total of 2180 minutes of ultrasound tape recordings, with 136.2 minutes of fetal body movements (6.2%) and 207.8 minutes of fetal breathing movements (9.5%). Mean (+/- standard deviation) observation times per patient before and after tablet insertion were 60.3 +/- 1.2 and 56.4 +/- 1.2 minutes for the PGE2 group and 60.1 +/- 1.3 and 60.4 +/- 1.1 minutes for the control group. Three hours after PGE2 insertion, there were significant decreases in the percentage of time occupied by body movements (7.8 +/- 3.1 versus 3.4 +/- 2.0%; P < .003) and breathing movements (10.6 +/- 8.6 versus 3.9 +/- 2.3%; P < .007). Three hours after tablet insertion, there were statistically significant decreases in the percentage of time occupied by body movements (P < .025) and breathing movements (P < .01) between the control and study groups. CONCLUSION: Induction of labor with intravaginal PGE2 tablets inhibits fetal body and breathing movements. The effects could be due to direct action on the fetus or indirect effects of PGE2 (through uterine contraction and/or endogenous PG).

Dinoprostone↗

PubMed1992

Chorionic villus sampling: transabdominal versus transcervical approach in more than 4000 cases.

OBJECTIVE: To address the evolving trends in the choice of transabdominal or transcervical chorionic villus sampling (CVS) at a teaching hospital and to evaluate the influence of gestational age on the approach chosen. METHODS: We analyzed our CVS data base, which contained information from 1986-1991. The proportions of transabdominal and transcervical CVS were tabulated for each year. In addition, the distribution of the CVS approaches over the various gestational ages was examined. RESULTS: During the study period, 4290 CVS procedures were performed. The rate of the transabdominal technique was stable at about 15% per year except for the first 2 years, when essentially all procedures were transcervical. Use of transabdominal CVS increased with advancing gestational age, from 3.6% at less than 10 weeks' gestation to 97.6% at greater than 14 weeks (chi 2 = 120, P less than .001; r = 0.791). CONCLUSIONS: The choice between the transabdominal and transcervical approach to CVS largely reflects the route emphasized during the physician's training. When choice is based strictly on technical limitations due to placental position, the overall transabdominal CVS rate is approximately 15%. A shift from transcervical to transabdominal CVS occurs with increasing gestational age as the placenta gains bulk and moves away from the cervix. After 14 weeks' gestation, most procedures are performed transabdominally.

Chorionic Villi Sampling↗

PubMed1992

Nonimmune hydrops fetalis and fetal congenital syphilis. A case report.

Nonimmune hydrops fetalis occurred secondary to a syphilitic infection. Ultrasonographic evaluation and cordocentesis were used to confirm the antenatal infection. An IgM antibody specific for Treponema pallidum wall antigen (anti-47-kDa) was used to document the fetal infection. High-dose intravenous penicillin was administered in an attempt to achieve adequate fetal levels.

Adolescent↗

PubMed1992

Evolution of hydranencephaly following intracerebral hemorrhage.

A circumscribed hyperechoic mass in the mid-portion of the left cerebral hemisphere was the presenting ultrasonographic finding in a 30-week fetus. With repeat ultrasound studies, this echo-dense mass became more sonolucent. In addition, there was an increased fluid accumulation and loss of identifiable cerebral cortex over the left parietal and occipital lobes. The patient underwent induction of labor because of progressive intracranial fluid accumulation with subsequent macrocephaly. The infant died on the fourth day of life. At necropsy, an organizing hematoma with admixtures of fresh and moderately degraded old blood was found in the left hemisphere. There was extensive resorption of the underlying cortex, leaving only a fluid-filled cavity with a meningeal covering. We believe the progressive changes that occurred after fetal intracerebral hemorrhage ultimately resulted in hydranencephaly.

Adult↗

PubMed1992

Determinants of parental decision to abort or continue after non-aneuploid ultrasound-detected fetal abnormalities.

OBJECTIVE: This study evaluated factors influencing the decision to abort after abnormalities in the karyotypically normal fetus were found through ultrasonography. METHODS: We reviewed all pregnancies complicated by ultrasound-detected abnormalities managed on our service from April 1990 through August 1991 (N = 262). Cases with associated karyotypic abnormalities were excluded (N = 35), as were cases diagnosed after the legal gestational age limit for abortion (N = 68). The remaining 159 cases were stratified into prognosis groups of "severe," "uncertain," and "mild." RESULTS: The prognostic severity of the ultrasound abnormality strongly correlated with the decision to abort (P less than .0001). Rates of termination were 0, 12, and 66% in the "mild," "uncertain," and "severe" groups, respectively. The patients' age, gravidity, and parity, and the fetal gestational age at diagnosis did not differ significantly between the groups. CONCLUSIONS: 1) In non-aneuploid pregnancies with an ultrasound diagnosis of fetal abnormality, the major predictor of the decision to abort was the severity of fetal prognosis. 2) The gestational age at diagnosis was not an important variable in the decision to abort for fetal structural abnormalities. 3) Parents who had fetuses with abnormalities associated with uncertain prognoses usually opted to continue the pregnancy. This appeared to be particularly true for defects that were potentially correctable in utero or by neonatal intervention (even if investigational).

Abortion, Induced↗

PubMed1992

Intravascular transfusion of fetuses with rhesus incompatibility: prediction of fetal outcome by changes in umbilical venous pressure.

OBJECTIVE: We examined whether abnormal elevations in umbilical venous pressure during intravascular transfusion predict post-transfusion mortality. METHODS: Umbilical venous pressures were measured during intravascular transfusion of human fetuses with Rhesus incompatibility. Five fetuses died within 24 hours after transfusion and nine fetuses survived the procedure. RESULTS: Survivors and non-survivors were similar in demographic and clinical data, as well as in transfusion characteristics. The only difference between the groups was the change in umbilical venous pressure during the transfusion: 5.0 +/- 6.3 mmHg for survivors versus 18.1 +/- 10.4 mmHg for non-survivors (P = .01). An increase in the umbilical venous pressure of 10 mmHg or more predicted fetal death with a sensitivity of 80% and specificity of 89%. CONCLUSION: Based on these results, we have modified our transfusion technique. If the change in umbilical venous pressure during intravascular transfusion approaches 10 mmHg, we discontinue the procedure. If the change in pressure exceeds 10 mmHg during transfusion, we remove blood and replace it with an equal volume of saline.

Blood Transfusion, Intrauterine↗

PubMed1992

Fetal intracardiac potassium chloride injection to avoid the hopeless resuscitation of an abnormal abortus: I. Clinical issues.

OBJECTIVE: With the intention of preventing the attendant medical, ethical, and legal problems arising from the birth of live-born, anomalous fetuses, we initiated a program offering fetal intracardiac potassium chloride injection as an adjunctive measure in the setting of genetically indicated second-trimester abortion. METHODS: A lethal fetal injection was offered to patients carrying chromosomally or structurally abnormal fetuses at 19-24 weeks' gestation who desired abortion. When the patient elected this procedure, real-time ultrasound guidance was used to inject 3-5 mL of potassium chloride (2 mEq/mL) directly into the fetal cardiac chambers, followed by observation of fetal heart activity to ascertain cessation. Labor was subsequently induced with uterotonic prostaglandins. RESULTS: The procedure caused immediate cessation of fetal heart motion in 20 of 21 cases. There were no maternal complications. No fetuses were live-born. CONCLUSIONS: Direct fetal intracardiac potassium chloride injection effectively causes immediate fetal cardiac arrest. This approach may be adopted in cases of abortion by labor-induction methods at advanced gestations to ensure that the abortus is stillborn.

Abortion, Eugenic↗

PubMed1991

Fetal supraventricular tachycardia and hydrops fetalis: combined intensive, direct, and transplacental therapy.

A 25-week fetus with severe hydrops fetalis secondary to supraventricular tachycardia was treated with fetal intramuscular injections of digoxin in conjunction with maternal intravenous digoxin, followed by oral digoxin and subsequently by oral procainamide therapy. Fetal umbilical blood sampling revealed poor placental transfer of digoxin, even after 2 weeks of therapeutic maternal levels. This case suggests that direct fetal therapy is of value in the treatment of some fetuses with supraventricular tachycardia, and lends further evidence that the role of transplacental digoxin therapy is limited in the compromised fetus. It also demonstrates that resolution of hydrops may require a prolonged period.

Adult↗

PubMed1991

Indomethacin for preterm labor: fetal toxicity in a dizygotic twin gestation.

Indomethacin was given for the treatment of preterm labor in a twin pregnancy at a dosage of 200 mg/day for 7 days beginning at 34 weeks and 5 days' gestation. During treatment, one twin developed closure of the ductus arteriosus, tricuspid regurgitation, right ventricular dysfunction, and pericardial effusion. Severe oligohydramnios in both amniotic sacs appeared as well. All findings resolved within 7 days of discontinuation of the medication. The infants, delivered vaginally at 37 weeks' gestation, were alive and well at a 2-month follow-up visit. We believe that all fetuses of mothers treated with indomethacin should be closely monitored for early evidence of decreased amniotic fluid volume and constriction of the ductus arteriosus.

Abnormalities, Drug-Induced↗

PubMed1991

Transvaginal pressure pack for life-threatening pelvic hemorrhage secondary to placenta accreta.

A patient with placenta previa presented with severe vaginal bleeding. Emergency classical cesarean was followed by hysterectomy for placenta accreta. The patient's hemodynamic status continued to deteriorate and she subsequently developed a consumptive coagulopathy secondary to massive hemorrhage. A mushroom-shaped pack, created from a sterile plastic bag filled with Kerlix gauze, was placed in the pelvis and brought out through the vagina. Traction on the pack produced pressure against the pelvic floor, controlling the bleeding. This pack was prepared quickly and removed without complication in the immediate postoperative period.

Adult↗

PubMed1989

Physostigmine, tacrine and metrifonate: the effect of multiple doses on acetylcholine metabolism in rat brain.

The effects of two consecutive intramuscular doses of three cholinesterase inhibitors (physostigmine, tetrahydroaminoacridine and metrifonate) were compared in rats. The results revealed major differences in biochemical effects on the brain of the rat including the extent and duration of inhibition of cholinesterase, inhibition of release of acetylcholine and increase in levels of acetylcholine. Side effects were also markedly different in the time of appearance, duration and severity. These results suggest that there are significant differences in the mechanisms of action of various cholinesterase inhibitors. Since all three cholinesterase inhibitors are currently used in the experimental treatment of Alzheimer's disease, these findings have potential implications for the symptomatic therapy of these patients.

Acetylcholine↗

PubMed1987

Pharmacokinetics and pharmacodynamics of physostigmine after intravenous administration in beagle dogs.

The time course of physostigmine (Phy), its metabolites and activity of cholinesterase (ChE) in plasma were studied after intravenous bolus administration of [3H]Phy (100 micrograms/kg) to beagle dogs. The maximal inhibition of ChE (78%) in plasma at 2 min correlated with the largest concentration of physostigmine (124 ng/ml). The concentration of physostigmine decreased by 88% to 16 ng/ml at 45 min when the activity of ChE was still 59% inhibited. Acetylcholinesterase activity in four regions of the brain (medulla, striatum, cerebellum and cortex) was not significantly different from controls at 70 +/- 5 min after administration of physostigmine. Concentrations of physostigmine and its metabolites determined by HPLC were not significantly different in different regions. In plasma, physostigmine was found, together with eseroline and two other metabolites M1 and M2. At 45 min, only 18% of total radioactivity was due to physostigmine and 52% was due to the major metabolite M1. On the contrary, in regions of the brain, metabolite M1 represented only 1.9-3.37% of total radioactivity at 70 +/- 5 min. Pharmacokinetic parameters, obtained in the dog, were compared to previously published data in rat and man. The elimination half-life (beta) was 30.7 min in the dog as compared to 15 min in rat and and 21.7 min in man. The Vd (ml/kg) was higher than total body water volume in all three species: dog (1832), rat (1352) and man (664), indicating sequestration of the drug in body compartments. Clearance (ml/min/kg) was found to be 41.2 in dog, which compares to 62 in rat and 22 in man.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗