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Biomedical subjects

W H Clewell

Publications and source records attributed to W H Clewell.

36 records · Page 2Linked to original sources
PubMed1985

Clinical course of fetal hydrocephalus: 40 cases.

The clinical course and outcome of hydrocephalus diagnosed in utero is not well understood. To approach this problem 40 cases were reviewed of intrauterine fetal hydrocephalus diagnosed with sonography, and follow-up information was obtained regarding them. Sonograms were evaluated for cerebral dimensions, biparietal diameter, brain mantle size, ventricular ratio, amount of amniotic fluid, and associated abnormalities. Neonatal brain sonograms and computed tomographic (CT) scans were reviewed also. Clinical charts were reviewed for maternal age and parity, referral source, family history, fetal age at diagnosis and delivery, mode of delivery, physical examination and/or autopsy findings, karyotype, amniotic alpha 1 fetoprotein level, cause of death, shunt placement after birth, and status of live infants. The observations indicate that the prognosis for fetal hydrocephalus is poor. Only six infants (15%) were alive after an average follow-up of 13 months. Three children were normal and the other three had neurologic abnormalities ranging from severe (paralysis and incontinence) to minimal (2-3 months delayed motor development). Thirty-four fetuses or neonates died. Nine families elected to terminate pregnancy. Ten opted for decompression at delivery for progressive hydrocephalus. Neural tube defects were present in 12 of 23 infants at delivery. Fourteen other infants had additional significant congenital abnormalities. Other abnormal sonographic findings included polyhydramnios (13 of 38), oligohydramnios or decreased fluid (nine of 38), neural tube defect (nine of 40), and other congenital abnormalities (nine of 40). These findings indicate that hydrocephalus diagnosed in utero by sonography is caused by a heterogeneous group of disorders. In general, the prognosis for normal development is poor. Individual prognoses, however, depend on the specific malformations and the interventions used.

Female↗
PubMed1985

The clinical significance of increased echogenicity in the fetal abdomen.

Seven cases of increased echogenicity in the fetal abdomen detected on prenatal sonography were reviewed for findings and causes. In four cases, the findings corresponded to calcification secondary to meconium peritonitis, infection, or unknown cause. One infant with meconium ileus had inspissated but noncalcified meconium corresponding to the increased echoes. In two cases, follow-up prenatal sonography was normal, and the neonate was also normal. Eight cases from the literature with increased echogenicity in the fetal abdomen were also reviewed: Two cases were secondary to meconium ileus, and six were caused by meconium peritonitis. Increased abdominal echogenicity on prenatal sonography may result from various processes that may affect obstetric and neonatal management.

Abdomen↗
PubMed1985

Intra-uterine shunting procedures.

Modern realtime ultrasound equipment and interpretation have presented physicians with a new type of patient, i.e. the fetus. The fetus suffers all the diseases we know as birth defects, but in their formative stages. Two conditions, namely obstructive uropathy and obstructive hydrocephalus, appear to be amenable in some cases to treatment in utero. Animal models for these conditions have been developed and the first attempts to treat the disorders in humans have been made. While many questions remain unanswered, some initial observations and conclusions can be drawn from this experience.

Amniotic Fluid↗
PubMed1982

Fetal treatment 1982.

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Congenital Abnormalities↗
PubMed1982

A surgical approach to the treatment of fetal hydrocephalus.

Untreated fetal hydrocephalus results in gross cranial and facial abnormalities and profound brain damage. In an attempt to prevent both, a ventriculoamniotic shunt was implanted in a fetus with probable X-linked aqueductal stenosis and hydrocephalus. Performed at 24 weeks' gestation, the procedure used techniques similar to those used for intrauterine transfusion. After shunt placement, the fetal head size grew normally until after the 32d week, when the shunt failed. A cesarean delivery was performed at 34 weeks' gestation. The infant received a standard ventriculoperitoneal shunt after delivery, and his neonatal course has been evaluated through the first three months of life. In selected cases, the ventriculoamniotic shunt may be an acceptable treatment for fetal hydrocephalus.

Adult↗
PubMed1981

Fetal transfusion with real-time ultrasound guidance.

A technique of fetal transfusion using sonographic guidance for needle placement is described. Sixteen patients underwent a total of 43 transfusions. The fetal mortality risk appears to be lower than that encountered in fluoroscopy-directed transfusions. Fetal irradiation has been dramatically reduced from an average of 2.2 rads per transfusion to 0.29 rads per transfusion. The technique allows very precise placement of a needle within the uterus or fetus. We have used it in difficult cases for amniocentesis. The technique could also be adapted to other problems requiring accurate placement of a needle within the body, such as biopsy of masses or aspiration of cysts.

Blood Transfusion, Intrauterine↗
PubMed1980

Stimulus summation and tachyphylaxis in estrogen response in sheep.

The response of the uterine circulation to estrogen has been extensively studied. Estrogen is the most potent vasodilator of the uterine bed. The magnitude of the vascular response depends on both the dose of estrogen used and the duration of exposure to estrogen. In this study, the relationship between the arterial concentration of estrogen, the duration and pattern of exposure, and the response was studied. This is a complex relationship, but one that is consistent with accepted models of estrogen-target tissue interaction. It was also shown that prolonged, high-concentration exposure results in tachyphylaxis.

Animals↗
PubMed1979

Prematurity.

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Birth Weight↗
PubMed1978

Changes in cervical compliance at parturition independent of uterine activity.

A new animal model has been developed to measure intrinsic changes of cerivcal compliance during spontaneous parturition or exposure to hormonal manipulation. Intermittent measurements of cervical compliance and continous measurements of uterine and cervical pressure were made during the last month of gestation of nine pregnant ewes. Cervical compliance increased abruptly and dramatically during spontanous and dexamethasone-induced parturition. Maternal progesterone supplementation at parturition inhibited uterine contractions but not the increase in cervical compliance, demonstrating the independence of the two events. The cervix was found to contract rhythmically and vigorously with a gradual decrease in activity as parturition approached.

Animals↗
PubMed1977

Comparison of uterotrophic and vascular effects of estradiol-17beta and estriol in the mature organism.

Estradiol-17beta (E2) has been considered the most potent of the natural estrogens in terms of uterine growth and vasodilatation. As a result of studies of uterine growth in rodents, estriol (E3) has been considered an "impeded" estrogen. In this study, direct comparisons of the actions of E2 and E3 on the sheep uterus were made in nonpregnant, oophorectomized ewes by using bilateral uterine artery catheters and electromagnetic flow transducers. Intra-arterial injections of E2 or E3 had equal growth-promoting and vascular effects. There were slight but statistically significant differences in the time course of vasodilatation. Estriol induced a more prolonged dilatation than did estradiol.

Animals↗