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Biomedical subjects

M A Harper

Publications and source records attributed to M A Harper.

At least 19 recordsLinked to original sources
PubMed1998

Early amniocentesis: effect of removing a reduced volume of amniotic fluid on pregnancy outcome.

In mid-trimester amniocentesis (MTA), 12-15 ml of amniotic fluid is aspirated for cytogenetic analysis. When a similar volume of amniotic fluid is removed by early amniocentesis (EA), it represents a significant proportion of the total amniotic fluid volume in the first trimester. The fluid depletion, which may persist for 7 to 10 days, is considered to impair development of fetal lungs and extremities and, possibly, contribute towards procedure-related congenital abnormalities and miscarriages. By only removing 7 ml of amniotic fluid, we have demonstrated a total miscarriage rate (3.8 per cent) comparable with previous large studies (Table V), a low incidence of respiratory difficulties at birth (2.7 per cent) and a low incidence of fixed flexion deformities (1.6 per cent), at the expense of a small increase in the incidence of culture failure (2.2 per cent).

Abortion, Spontaneous↗
PubMed1998

Transplacental early amniocentesis and pregnancy outcome.

The effect on pregnancy outcome of transplacental needle insertion was studied in 401 consecutive women attending for early amniocentesis between 10 and 14 completed weeks of pregnancy. Transplacental early amniocentesis was associated with a significantly higher incidence (P < 0.001) of blood-stained amniotic fluid taps but a lower incidence (not significant; P > 0.05) of pregnancy loss and miscarriages. Women in the nontransplacental early amniocentesis group had a significantly higher (P < 0.01) incidence of late procedure-related antenatal complications, such as preterm rupture of membranes or preterm labour. Our study showed that transplacental early amniocentesis is a safe procedure; contrary to present recommendations, the study also showed that avoiding the placenta during early amniocentesis is an unnecessary practice.

Amniocentesis↗
PubMed1995

Successful pregnancy in association with Zollinger-Ellison syndrome.

Persistent severe vomiting in pregnancy may be caused by underlying disease and should be investigated. A patient with intractable vomiting associated with abdominal pain and dental enamel erosion in two pregnancies had a gastrinoma. Symptoms were successfully controlled with omeprazole in a third pregnancy. All three babies were healthy.

Adult↗
PubMed1994

Triploid partial molar pregnancy detected through maternal serum alpha-fetoprotein and HCG screening.

BACKGROUND: Screening for Down syndrome using maternal serum alpha-fetoprotein (MSAFP) and hCG, with or without unconjugated estriol (E3), has become standard practice in much of the United States. When both MSAFP and hCG are elevated, the possibility of a partial molar pregnancy with fetal neural tube or abdominal-wall defect should be added to the differential diagnosis, as illustrated by this case. CASE: A 22-year-old woman had elevated MSAFP and hCG levels on routine screening at 16 weeks' gestation. Ultrasound examination suggested a neural tube defect and a thickened placenta. Amniocentesis was performed. She very rapidly developed preeclampsia. Fluorescence in situ hybridization showed three distinct spots for the three probes tested. A triploid karyotype was confirmed with standard cytogenetic analysis. The fetus had an open neural tube defect, and placental pathology was consistent with a partial hydatidiform mole. CONCLUSIONS: A possible partial molar pregnancy with abdominal-wall or open neural tube defect should be added to the differential diagnosis for interpreting Down syndrome screens when both MSAFP and hCG are elevated. A presumptive diagnosis of triploidy using fluorescence in situ hybridization was important in the management of this pregnancy.

Adult↗
PubMed1993

Myocardial infarction during pregnancy: management and outcome of two pregnancies.

OBJECTIVE: Each year in the United States approximately 500,000 women die from ischemic heart disease. However, there are < 100 reported cases of myocardial infarction occurring during pregnancy. The current management of these patients is empiric, with pulmonary artery catheterization during labor being frequently reported. STUDY DESIGN: In the past year we have managed and delivered two such patients, including the first reported case of myocardial infarction with a triplet gestation. RESULTS: Both patients had clinical and laboratory signs of myocardial infarction and underwent coronary angiography. They subsequently had preeclampsia and were prematurely delivered of viable fetuses. One patient had angina pectoris during labor and was successfully treated with sublingual nitroglycerin. Neither patient suffered reinfarction or heart failure. Invasive hemodynamic monitoring was not used, and the mode of delivery was determined solely on obstetric indications. CONCLUSION: In pregnant patients with myocardial infarction, invasive central monitoring is unnecessary in patients with good cardiac function and reserve and the mode of delivery should be based on obstetric indications.

Adult↗
PubMed1993

Immature lecithin/sphingomyelin ratios and neonatal respiratory course.

OBJECTIVE: We hypothesized that the absolute value of an immature lecithin/sphingomyelin ratio, in addition to gestational age and birth weight, contributes significantly to predicting the clinical course of the neonate. The lecithin/sphingomyelin value may therefore enhance clinical decision-making regarding timing of delivery and use of tocolytics in high-risk pregnancies. STUDY DESIGN: One hundred four mother-baby pairs with delivery within 72 hours of an immature lecithin/sphingomyelin determination in the 3-year period immediately before the initiation of surfactant therapy in our hospital were retrospectively reviewed. Stepwise regression was performed for the independent variables of gestational age, birth weight, and lecithin/sphingomyelin values in a linear model to predict total days of respiratory support (oxygen, continuous positive airway pressure, or mechanical ventilation). RESULTS: In the patients without preterm premature rupture of membranes the lecithin/sphingomyelin value was the best predictor of duration of respiratory support (R2 = 0.2426, F = 12.4908, p = 0.011). After gestational age was controlled for, there was a significant inverse correlation between the lecithin/sphingomyelin value and days of respiratory support (F = 4.634, p = 0.031). In the patients with preterm premature rupture of membranes with vaginally collected fluid, however, lecithin/sphingomyelin values did not contribute significantly in predicting duration of respiratory support. Rupture-to-delivery interval and gestational age were the best predictors in this group. CONCLUSION: Although a mature lung profile is the ideal situation, preterm delivery may be indicated in pregnancies complicated by maternal disease or evidence of possible fetal compromise. We conclude that in patients without premature rupture of membranes the absolute value of the immature lecithin/sphingomyelin ratio is a better predictor than gestational age or birth weight of duration of respiratory support and should be considered in timing of delivery.

Amniotic Fluid↗
PubMed1990

Tuboovarian pregnancy associated with elevated maternal serum alpha-fetoprotein. A case report.

Tuboovarian implantation is a rare form of pregnancy that is difficult to diagnose in early gestation. A patient with a tuboovarian pregnancy presented with abnormally elevated initial screening maternal serum alpha-fetoprotein (MSAFP). The elevated MSAFP and a pelvic mass of uncertain etiology on ultrasonography delayed the diagnosis until laparotomy was performed. Elevated MSAFP accompanied by oligohydramnios and a pelvic mass is a particularly suspect finding for a tuboovarian or other type of extrauterine implantation.

Adult↗
PubMed1989

Phaeochromocytoma in pregnancy. Five cases and a review of the literature.

We report five patients with phaeochromocytoma associated with pregnancy and review the 42 other cases reported in the literature from 1980 to 1987. The overall maternal mortality was 17% and the fetal loss 26%; antenatal diagnosis of phaeochromocytoma reduced the maternal mortality to zero and the fetal loss to 15%, but was made in only 53% of the patients. Although phaeochromocytoma is rare, a high index of clinical suspicion must be maintained and all those at risk investigated if earlier diagnosis and improved outcome are to be achieved. Once the diagnosis is confirmed, alpha-blockade is essential and beta-blockade may be required. CT scan or magnetic resonance imaging may be used to localize the tumour during the antenatal period. In the first and second trimesters, tumour resection has a good fetal outcome; in later pregnancy, delivery by elective caesarean section followed by tumour resection is recommended.

Adrenal Gland Neoplasms↗
PubMed1988

Arginine vasopressin infusion stimulates adrenocorticotropic hormone and cortisol release in the ovine fetus.

Arginine vasopressin may play a role in the control of adrenocorticotropic hormone release during stress in the adult animal. Arginine vasopressin is also considered an important stress hormone in the fetus. The effect of arginine vasopressin infusion on adrenocorticotropic hormone release in the fetus was investigated in 14 chronically cannulated ovine fetuses with normal blood gas and pH values between 103 and 137 days' gestation. There was a significant increase in adrenocorticotropic hormone and cortisol levels during a 30-minute infusion of arginine vasopressin. Plasma renin activity was unchanged. The corticotropin-releasing activity of arginine vasopressin was not blocked by pretreatment with a V1-receptor antagonist and was not significantly different when the pressor response was attenuated by sodium nitroprusside infusion.

Adrenocorticotropic Hormone↗
PubMed1987

Vasopressin-induced bradycardia in fetal and adult sheep is not dependent on an increase in blood pressure.

Other investigators have reported that intravenous infusion of synthetic arginine vasopressin into fetal lambs increases mean arterial pressure and decreases heart rate. To determine if the bradycardia produced by arginine vasopressin is a reflex response to the increase in blood pressure, we studied the effect of arginine vasopressin infusion on heart rate with and without blocking the increase in blood pressure. We performed 34 experiments in 12 chronically cannulated fetal lambs between 103 and 137 days' gestation. All animals had normal blood gas and pH values. Infusion of arginine vasopressin increased mean arterial pressure 10.1 +/- 1.1 mm Hg and decreased heart rate 50 +/- 8 bpm. Fetal heart rate decreased similarly when arginine vasopressin was infused and the hypertensive response was blocked with nitroprusside or a selective vasoconstrictor antagonist. [1-(beta-mercapto-beta,beta-cyclopentamethylene propionic acid) 2-(O-methyl)tyrosine] arginine vasopressin. For comparison we also studied five adult nonpregnant ewes. Bradycardia was observed in the adults after infusion of arginine vasopressin alone and when the hypertensive response was blocked with the vasoconstrictor antagonist. We conclude that arginine vasopressin infusion causes a fall in heart rate independent of any increase in blood pressure in both the fetal lamb and the adult sheep.

Animals↗
PubMed1987

Human fetal breathing response to intravenous glucose is directly related to gestational age.

This prospective longitudinal study examined human fetal breathing activity over the second half of pregnancy both in the fasting state and after intravenous glucose administration. There was a linear relationship between gestational age and percent time spent breathing after glucose between 19 and 38 weeks' gestation. However, no such correlation could be demonstrated between gestational age and fetal breathing activity in the fasting state.

Embryonic and Fetal Development↗
PubMed1983

Comparison of tubal surgery with the CO2 laser and the unipolar microelectrode.

The uterine horns of 40 New Zealand White female rabbits were resected and anastomosed to compare microsurgical anastomosis of the horns excised with microscissors, with a laser, and with a microelectrode. The rabbits were divided into four groups. In the first group of ten rabbits, 3 cm of tissue was resected by microscissors from each uterine horn; the cut ends were then anastomosed in one layer with 8-0 Vicryl sutures using the operating microscope. In the second group of ten rabbits, 3 cm of tissue was resected by laser from each uterine horn; the cut ends were then anastomosed in one layer with 8-0 Vicryl. In the third group of ten rabbits, 3 cm of tissue was resected by laser from each uterine horn; the cut ends were then anastomosed by "welding" the tissues with the laser. In the fourth group of ten rabbits, 3 cm of tissue was resected by a microelectrode; the cut ends were then anastomosed in one layer with 8-0 Vicryl sutures using loupe magnification. All the rabbits in the first and fourth groups became pregnant, only four became pregnant in the second group, and none became pregnant in the third group. It is concluded that the CO2 laser beam as used in this study has no place in tubal resection and reconstruction.

Animals↗
PubMed1977

Cerebral circulatory and metabolic effects of 5-hydroxytryptamine in anesthetized baboons.

1. The cerebral circulatory effects of the intracarotid administration of 5-hydroxytryptamine were examined in anaesthetized baboons. Cerebral blood flow was measured by the intracarotid 133Xe technique, cerebral O2 consumption and glucose uptake were measured as indices of brain metabolism and electrocortical activity was continuously monitored. 2. Despite a marked reduction in the calibre of the internal carotid artery (assessed angiographically), the intracarotid infusion of 5-hydroxytryptamine 0-1 microgram/kg. min did not effect any significant changes in cerebral blood flow, O2 consumption or glucose uptake. 3. Following transient osmotic disruption of the blood-brain barrier with the intracarotid infusion of hypertonic urea, the same dose of 5-hydroxytryptamine effected a marked reduction in cerebral blood flow from 51 +/- 2 to 36 +/- 2 ml./100 g. min (mean +/- S.E.; P less than 0-01). Both indices of cerebral metabolism were reduced significantly and the e.e.g. showed a more pronounced suppression-burst pattern. 4. We postulate that the cerebral circulatory responses to 5-hydroxytryptamine are dependent upon the integrity of the blood-brain barrier and the predominant effect of the intravascular administration of 5-hydroxytryptamine is on cortical activity or metabolism, rather than on cerebrovascular smooth muscle.

Animals↗