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Biomedical subjects

J W Larsen

Publications and source records attributed to J W Larsen.

At least 19 recordsLinked to original sources
PubMed1995

Advent of maternal serum markers for Down syndrome screening.

Trisomy 21, or Down syndrome, is the most common serious autosomal chromosome aberration in which affected individuals survive beyond infancy. The association between advancing maternal age and increased risk of trisomy 21 is well known, and pregnant women older than 35 years at delivery are routinely offered invasive prenatal diagnostic testing. More recently, the use of maternal serum markers in the second trimester of pregnancy to predict the risk of trisomy 21 for women under the age of 35 has received intensive analysis. Maternal serum alpha-fetoprotein (MSAFP) was the first of these markers to be identified, and an inverse correlation between MSAFP level and risk of trisomy 21 was noted. A second marker, unconjugated estriol (uE3), has also been studied, and a correlation between low uE3 and trisomy 21 has been demonstrated, with a high level of correlation between AFP and uE3. The addition of uE3 to the screening protocol has not consistently improved detection rates, possibly because of its high correlation with AFP. A strong association of human chorionic gonadotropin (hCG) and Down syndrome was reported. This analyte is the most sensitive one in use today, although controversy exists regarding the best form of the analyte to use for trisomy 21 prediction. Several groups of investigators advocate measurement of total hCG, while others feel that measurement of the free-beta subunit of the molecule offers greater detection ability. The maximum detection rate that has been reported is 80 percent with a 5 percent false-positive rate using a combination of MSAFP, free-beta hCG, and maternal age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Diagnosis of abnormalities of the human fetus during the first, second, and third trimesters.

Clinical teratologists will have new challenges during the 1990s as birth defects are diagnosed more frequently than in previous decades. Malformations and genetic disorders will be diagnosed in utero during all three trimesters of pregnancy. The teratologist may participate in or lead a multispecialty group to give the involved family optimal interpretation of test results, counseling, and recommendations regarding subsequent clinical management.

Congenital Abnormalities↗
PubMed1990

Trisomy 22 with holoprosencephaly: a clinicopathologic study.

Trisomy 22 (47, XY, +22) was found at 17 weeks gestation in one fetus of a twin gestation. The karyotypes of both parents and of the other twin were normal. Abnormal prenatal findings included maternal pre-eclampsia, fetal growth retardation, and progressive intracranial sonolucency of the trisomic fetus. Delivery by cesarean section at 36 weeks gestation yielded a normal healthy female weighing 2,822 grams and a markedly macerated dysmorphic male weighing 642 grams. Holoprosencephaly was found in the trisomic fetus, an unusual feature in trisomy 22. Additional findings in this case are compared to other findings in the literature.

Adult↗
PubMed1990

Maternal serum Down syndrome screening: free beta-protein is a more effective marker than human chorionic gonadotropin.

The use of quantitative human chorionic gonadotropin measurement in obstetrics has a long and successful history. Prior studies on the utility of human chorionic gonadotropin in Down syndrome screening have utilized assays that measure the intact human chorionic gonadotropin molecule. This study targeted a distinct marker, the human chorionic gonadotropin free beta-protein, which is present in second-trimester maternal serum at much lower concentrations than is intact human chorionic gonadotropin. Our study of 29 cases of trisomy 21 and 450 control samples shows 80% detection efficiency with maternal serum alpha-fetoprotein, the free beta-protein, and maternal age in pregnancies under 17 weeks' gestation. We conclude that the combination of maternal serum alpha-fetoprotein and the human chorionic gonadotropin free beta-protein will be useful in the prenatal detection of trisomy 21.

Antibodies, Monoclonal↗
PubMed1990

Maternal serum Down syndrome screening: unconjugated estriol is not useful.

Study of 41 known Down syndrome cases and 441 matched controls did not confirm earlier reports that low unconjugated estriol levels can be used to detect fetal Down syndrome. Hence the obstetric community should exercise caution in using unconjugated estriol levels as a marker in prenatal Down syndrome screening.

Down Syndrome↗
PubMed1990

Maternal serum alpha-fetoprotein (MSAFP) patient-specific risk reporting: its use and misuse.

Fundamental to maternal serum alpha-fetoprotein screening is the clinical utility of the laboratory report. It follows that the scientific form of expression in that report is vital. Professional societies concur that patient-specific risk reporting is the preferred form. However, some intermediate steps being taken to calculate patient-specific risks are invalid because of the erroneous assumption that multiples of the median (MoMs) represent an interlaboratory common currency. The numerous methods by which MoMs may be calculated belie the foregoing assumption.

Algorithms↗
PubMed1988

Three-dimensional computed tomography in maxillofacial surgical planning.

Fifty-four maxillofacial three-dimensional computed tomographic examinations were performed during a 12-month period for the purpose of surgical planning. Pathologic entities in the series included trauma, neoplasia, cleft palate, and other developmental anomalies. Computer-assisted mandibular disarticulation was performed routinely after each study to permit direct viewing of the mandible or maxilla in isolation. Three-dimensional computed tomography is a useful technique for maxillofacial surgical planning.

Adolescent↗
PubMed1988

Acardiac fetus in a triplet pregnancy.

The acardiac monster represents one of the most severe but rare congenital anomalies. It occurs only in multiple gestations associated with vascular anastomoses between the affected fetus and its co-twin. The prenatal diagnosis of an acardiac fetus must be suspected in any multiple gestation in which cardiac activity cannot be documented sonographically in a growing fetus. We report an acardiac fetus occurring in a spontaneously conceived triplet pregnancy. A review of the literature, including pathogenetic theories and sonographic reports, is discussed.

Abnormalities, Severe Teratoid↗
PubMed1988

Prenatal diagnosis of fetal anomalies using ultrasound and MRI.

In conclusion, it is unlikely that MRI will replace ultrasound as the primary obstetric imaging modality in the near future. Ultrasound has a proven record of accuracy and safety in addition to its easy access and low cost. MRI has promise, however, in providing crucial information in patients with underlying medical or surgical conditions that would ordinarily require ionizing radiation for evaluation. Currently, MRI is helpful in evaluating gross fetal anomalies and disturbances of fetal growth and development when ultrasound is limited by oligohydramnios or maternal obesity. Further experience is required to determine the value of spectroscopy and quantitative relaxation times regarding fetal metabolism and fetal well-being. Technologic improvements and software updates will reduce imaging time and increase spatial resolution, thus rendering MRI more competitive with existing imaging techniques. The ultimate role, however, that MRI will have in the evaluation of the fetus is currently undefined.

Congenital Abnormalities↗
PubMed1988

Prenatal diagnosis of cystic fibrosis by chorionic villus sampling using 12 polymorphic deoxyribonucleic acid markers.

This report describes the application of a genetic prenatal diagnostic test for cystic fibrosis to a family with a cystic fibrosis-affected child. The test uses 12 deoxyribonucleic acid (DNA) markers that bracket the cystic fibrosis gene on chromosome 7, and chorionic villus tissue as a source of DNA from the fetus at risk for cystic fibrosis. The fetus was predicted by DNA analysis to be unaffected (although a carrier of one cystic fibrosis gene); this diagnosis was confirmed postnatally by the standard sweat electrolyte test. The genetic linkage test is informative in more than 99% of families with cystic fibrosis-affected members and is also useful for determination of carrier status. The test is both more informative and more accurate than one based upon the markers Met and D7S8 (J3.11) alone. The analysis can be done directly from chorionic villus tissue, and therefore can provide a diagnosis as early as nine to 12 weeks after conception.

Adult↗
PubMed1987

Temporomandibular joint imaging. Practical application of available technology.

Clinical afflictions of the temporomandibular joint (TMJ) are common, but TMJ afflictions remain one of the most poorly understood and controversial areas of clinical practice. Theories of TMJ pathophysiology, diagnosis, treatment, and patient disposition abound. Many afflicted patients have undergone expensive, protracted, and fruitless therapeutic endeavors, many of which are without scientific basis, causing many health insurers to exclude evaluation and treatment of TMJ disorders from coverage. Medical imaging has a central role in establishing a correct diagnosis. Available imaging procedures include roentgenography, arthrography, videofluoroscopy, magnetic resonance imaging, and computed tomography.

Arthrography↗
PubMed1987

Genetic implications of idiopathic hydramnios.

The antenatal diagnosis of hydramnios requires a careful search for associated underlying maternal or fetal conditions. Even in pregnancies associated with idiopathic hydramnios in which no underlying condition can be identified, a high perinatal mortality rate exists. Although trisomy 18 has been seen in pregnancies with hydramnios and growth retardation, the association with specific chromosomal disorders and idiopathic hydramnios has not been well defined. A review of pregnancies complicated by hydramnios was undertaken; 99 cases with complete pregnancy and delivery information were identified. Fifty-nine pregnancies were complicated by idiopathic hydramnios, and except for the hydramnios, sonographic evaluation was normal. Delivery information revealed one infant with trisomy 18 and eight infants with structural anomalies not appreciated antenatally. Of the undiagnosed malformations, 25% are frequently associated with trisomy 21. We recommend fetal chromosomal analysis as an adjunct to the evaluation of pregnancies complicated by idiopathic hydramnios.

Chromosomes, Human, Pair 18↗
PubMed1987

Second-trimester polyhydramnios: evaluation with US.

The sonograms of 40 patients with second-trimester polyhydramnios were reviewed to determine (a) whether fetal and maternal conditions occur as often during second-trimester polyhydramnios as during third-trimester polyhydramnios, (b) the frequency of persistence of polyhydramnios into the third trimester, and (c) how sonography can help in maternal and fetal management. Second-trimester polyhydramnios often (62%) persisted into the third trimester. The frequencies of maternal (25%) and fetal (12%) conditions were similar to those previously reported for third-trimester polyhydramnios. Fetal anomalies were always identified on the sonogram that initially demonstrated polyhydramnios. Fetal outcome was excellent in the nondiabetic patient with polyhydramnios in whom no fetal abnormalities were detected on sonograms. In polyhydramnios associated with maternal diabetes mellitus, however, the pregnancy was often (71%) complicated by premature labor or macrosomia. In such patients serial sonographic follow-up is indicated.

Amniotic Fluid↗
PubMed1987

A simple method for gross examination of the brain in abortuses and macerated fetuses.

The use of maternal serum alpha-fetoprotein screening and sonography has led to an increase in the prenatal diagnosis of major central nervous system (CNS) malformations. Therefore, it is important to correctly identify the type of malformation for proper counseling. We describe an autopsy method--freezing and sectioning of the fetal head--that should increase the accuracy of diagnosis after second-trimester abortion.

Brain↗
PubMed1987

Postabortal septic pelvic thrombophlebitis diagnosed with computed tomography. A case report.

Septic pelvic thrombophlebitis is an uncommon complication in obstetrics and gynecology that may be difficult to diagnose clinically. Computed tomography (CT), an accurate and noninvasive modality, has greatly aided in the diagnosis of this disorder. In a case of septic pelvic thrombophlebitis complicating second-trimester pregnancy termination, CT enabled the correct diagnosis to be made and treatment to be initiated.

Abortion, Induced↗