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Biomedical subjects

J Wisser

Publications and source records attributed to J Wisser.

At least 19 recordsLinked to original sources
PubMed1998

Prenatal diagnosis of fetal malformations by ultrafast magnetic resonance imaging.

Prenatal ultrasonography is the primary imaging modality in pregnancy as it allows direct real-time fetal examination. Antenatal magnetic resonance imaging (MRI) has so far been of limited clinical value owing to poor image quality. This was due to the long acquisition times that were needed to achieve a high enough spatial resolution for assessment of the small fetal anatomic structures resulting in severe motion artefacts. This problem has now been overcome by recent technical improvements. We present a case of fetal malformation (MURCS association), where an ultrafast T2-weighted RARE sequence (single shot fast spin echo sequence) provided images of excellent quality, which led to the correct antenatal diagnosis. MRI using this sequence can now be used for prenatal diagnosis and is thus likely to become an important adjunct to ultrasonography, especially in cases in which ultrasound findings are unclear of sonographic images are impaired by maternal obesity or oligohydramnios.

Adult↗
PubMed1998

Pulsatility index in the fetal anterior tibial artery during the second half of normal pregnancy.

The objective of this prospective study was to establish reference values for the pulsatility index in the fetal anterior tibial artery during the second half of pregnancy. Pulsed Doppler waveform analysis of 203 fetuses at 23-42 weeks of pregnancy was performed, each fetus being examined just once. There were neither fetal nor maternal complications detectable at the time of the examination. In the first 14 fetuses from which recordings were taken, Doppler examination was performed on both fetal legs in order to evaluate systematic differences between the right and left legs. Intraobserver variability was analyzed by repetition of the measurements by the same examiner in the first 130 cases. There was no difference between right and left tibial circulation. The repeatability coefficient, defined as the 95% range for the difference in two repeat measurements, was 1.08. The pulsatility index of the anterior tibial artery (50th centile) increased slightly from 3.29 at 23 weeks of pregnancy to 4.09 at 42 weeks. The 5th and 95th centiles were calculated, as was the 95% confidence interval of the 5th and 95th centiles. Examination of the fetal peripheral circulation during the second half of pregnancy is possible with a high degree of precision. Whether there are changes in peripheral arterial circulation in compromised fetuses remains to be evaluated.

Female↗
PubMed1997

Lethal multiple pterygium syndrome: suggestion for a consistent pathological workup and review of reported cases.

We report on 2 brothers with lethal multiple pterygium syndrome (LMPS) born to non-consanguineous parents as late spontaneous abortions. Both fetuses presented with massive nuchal edema, and facial anomalies including cleft palate and broad ribs. Apparently, several subgroups of LMPS exist. Differentiation is difficult, as there is no consistent agreement on a workup protocol for autopsies. We compared the findings in the literature on cases with LMPS, and we suggest a standardized workup as an initial step for more efficient differentiation between various subgroups.

Abnormalities, Multiple↗
PubMed1997

Successful treatment of fetal megavesica in the first half of pregnancy.

OBJECTIVE: Our goal was to assess fetal kidney function in fetuses with megavesica diagnosed during the first half of pregnancy before treatment. STUDY DESIGN: In a prospective interventional study 9 fetuses with megavesica diagnosed during the first half of pregnancy underwent vesicocentesis. Fetal urine biochemical markers (urine electrolytes, osmolarity, and beta 2-microglobulins) were determined after diagnostic vesicocentesis of the fetal megavesica. RESULTS: Surprisingly, in four fetuses who underwent sampling at 13 to 18 postmenstrual weeks, vesicocentesis proved both diagnostic and therapeutic. Pregnancy proceeded with normal amniotic fluid volume, a normal-sized urinary bladder with normal dynamics, and normal postnatal renal function. A fifth fetus had trisomy 18. In three of the remaining four fetuses in whom sampling was performed at 16 to 20 postmenstrual weeks, biochemical markers indicated a poor prognosis. In the remaining fetus marginal results of biochemical studies prompted intrauterine treatment, but death from respiratory problems ensued after premature delivery at 31 weeks. CONCLUSIONS: Fetal megavesica in the first half of pregnancy is an indication for an immediate diagnostic vesicocentesis. This is the first report emphasizing early diagnosis of fetal megavesica with subsequent fetal vesicocentesis and demonstrating that this minimally invasive procedure can be life-saving if performed in early pregnancy.

Abdominal Muscles↗
PubMed1997

Reference resistance indices of the umbilical, fetal middle cerebral and uterine arteries at 24-42 weeks of gestation.

The objective of this cross-sectional study was to construct new reference ranges for Doppler flow velocity waveform resistance indices for the fetal umbilical artery, middle cerebral artery, placental and non-placental uterine arteries and the placentocerebral ratio in a large and minimally selected population attending a single clinic. Study design and data analysis adhered to a number of stringent and validated methodological recommendations derived both from the recent literature and from a review of earlier publications in this field. The final database comprised initial routine Doppler velocimetry at 24-42 weeks' gestation in 1675 pregnancies. Separate regression models were fitted to estimate the mean and standard deviation at each gestational age for each vessel. New charts, centile tables and regression equations are presented for the resistance indices of the fetal umbilical artery, middle cerebral artery, placental and non-placental uterine arteries and the mean of both uterine arteries and for the placentocerebral ratio.

Adult↗
PubMed1997

Prenatal diagnosis in Switzerland.

Switzerland, with a population of slightly over 7 million, has about 83,000 births per year. There is no comprehensive national registry for prenatal diagnosis (PND) or congenital malformations. Health care is largely organised within each of the 23 countries. Whereas ultrasound screening is available to all pregnant women, the availability of other types of PND is largely determined by proximity to the university medical centres or specialised clinics. Maternal biochemical serum screening is offered by some 15-20 laboratories, and cytogenetic analyses are performed in 8. DNA-based diagnosis is essentially limited to the medical genetics departments/divisions of the 5 university medical schools. It can be estimated that slightly over 10% of gestations are monitored by invasive prenatal diagnostic techniques. The greatest challenge for the future will be the training of the medical and paramedical personnel necessary for the current and future pre- and postnatal diagnostic testing.

Female↗
PubMed1997

[PARS--a software program for pathologic anatomic diagnosis of wild animals].

A computer programme (PARS) was designed for the collection of Pathological-Anatomical References of the Institute for Zoo Biology and Wildlife Research. We systemized more than 40,000 postmortem cases in order to develop a data bank for wild animal pathology. The PARS-programme was designed on the basis of PARADOX 7 for WINDOWS. As a netwoking programme with a central server it offers direct access to the data of the IZW case documentation for all scientists. In order to minimize desk work, the programme contains tables of zoological systemic (amphibians, reptiles, birds and mammals) as well as tables for systemic assignment (bacteria, viruses, fungi, protozoa, helminths and arthropods) for most common species. The records and findings of the necropsies can be printed immediately.

Amphibians↗
PubMed1996

[Obstetric ultrasonic studies in clinical practice].

Routine ultrasound screening during pregnancy is being debated. The paper presents the aims of a three-step ultrasound screening during pregnancy care. These are exact dating of the pregnancy, detection and classification of multiple pregnancies and the detection of fetal malformations. In order to achieve these goals, we describe these three examinations. In the Cochrane Database, the efficiency of routine ultrasound screening during pregnancy is presented. Consequences of pregnancy care without routine ultrasound examinations are discussed.

Congenital Abnormalities↗
PubMed1996

Diaphragmatic defects, limb deficiencies, and ossification defects of the skull: a distinctive malformation syndrome.

We report on prenatal and postnatal findings in 4 consecutive fetuses with a pattern of severe congenital anomalies who were born to a healthy nonconsanguineous couple. The spectrum of malformations includes diaphragmatic defects, hypoplastic lungs, omphalocele, limb deficiencies, syndactyly of toes, and ossification defects of the skull. This specific spectrum of anomalies is not fully compatible with that of any established syndrome. No prenatal exposure to any possible teratogen was found. Family history is suggestive for autosomal recessive inheritance, even though germ-line mosaicism in one of the parents cannot completely be excluded.

Abnormalities, Multiple↗
PubMed1995

Prenatal sonographic diagnosis of autosomal recessive polycystic kidney disease (ARPKD) during the early second trimester.

Autosomal recessive polycystic kidney disease (ARPKD) is a rare hereditary disease with a high neonatal mortality. Currently, prenatal diagnosis is possible only during the second half of pregnancy, when bilaterally enlarged, echogenic kidneys are visible by ultrasound. We describe a case in which a diagnosis of ARPKD was sought in the first half of pregnancy. High-resolution ultrasonography revealed echogenic, normal-sized kidneys at 15 + 4 weeks. Microsatellite DNA analysis of a chorionic villus sample, parental blood, and blood of an affected sibling showed that the fetus had the maternal haplotype and a recombination of the paternal haplotype. Thus, no distinction between homo- and heterozygosity for the ARPKD mutation in the fetus was possible. A further ultrasound examination at 19 + 4 weeks confirmed the previous results, indicating that the fetus was likely to be affected. After termination of the pregnancy, the diagnosis was confirmed on microscopic examination.

Adult↗
PubMed1995

A glycine 375-to-cysteine substitution in the transmembrane domain of the fibroblast growth factor receptor-3 in a newborn with achondroplasia.

Achondroplasia, the most common form of chondrodysplasia, has been associated with mutations in the gene of the fibroblast growth factor receptor-3 (FGFR-3) on chromosome 4p. All 39 achondroplasia alleles studied so far carried point mutations which caused the same amino acid exchange, a substitution of glycine by arginine at position 380 (G380R) in the transmembrane domain of the receptor. We report on a newborn with achondroplasia who does not carry a G380R mutation but has a mutation causing substitution of a nearby glycine with a cysteine (G375C). This observation indicates allelic heterogeneity and confirms the role of mutations in the transmembrane domain of FGFR-3 in the pathogenesis of achondroplasia.

Achondroplasia↗
PubMed1994

Temporomandibular joint disc replacement made by tissue-engineered growth of cartilage.

OBJECTIVE: To test the effectiveness of the new technique of tissue-engineered growth of cartilage, temporomandibular joint (TMJ) disc replacements were created by seeding dissociated chondrocytes on synthetic, three-dimensional, bioresorbable polymer constructs of a predetermined anatomic shape, incubating the cell-polymer constructs in vitro, and transplanting them into test animals. MATERIALS AND METHODS: Twelve highly porous and bioresorbable cell-transplantation devices in the shape of TMJ discs were created using biodegradable polylactid and polyglycolic acid fibers. Bovine articular cartilage was dissociated into chondrocytes and the cells were allowed to attach to the three-dimensional polymer scaffolds and multiply in vitro. After 1 week, the cell-polymer constructs were implanted subcutaneously into nude mice. The neocartilage was assessed by magnetic resonance imaging (MRI) techniques, gross inspection, histology, and biomechanical and biochemical analysis after 12 weeks. RESULTS: All implants seeded with chondrocytes showed gross evidence of histologically organized hyaline cartilage. The scaffolds maintained their specific shape. They not only showed appropriate intrinsic stability during neomorphogenesis of cartilage in vitro and in vivo, but also seemed to guide the growth of cartilage. The presence of sulfated glycosaminoglycans was shown by aldehyde fuchsin alcian blue staining of the specimens. Type II collagen, considered to be indicative of cartilage formation, was found in the specimens tested. MRI showed signal characteristics similar to those of hyaline cartilage. Analysis of neocartilage force/displacement curves and aqueous phase compliance using a closed compression chamber suggested that the ability of the constructs to resist deformation was similar to that of native donor cartilage. CONCLUSION: The technology of tissue-engineered growth of cartilage on individually designed scaffolds may have many applications not only in reconstructive surgery of the TMJ, but also in craniomaxillofacial, plastic, and orthopedic surgery.

Animals↗
PubMed1994

Embryonic heart rate in dated human embryos.

Using simultaneous B-mode and time-motion transvaginal ultrasonography we measured embryonic heart rate (EHR) in dated human embryos during the first trimester in a prospective study. In 160 pregnant women who had undergone assisted reproductive procedures, 139 singleton embryos and 46 embryos from 21 multiple pregnancies were studied between the 37th and 98th postmenstrual day. Because multiple measurements in one embryo at different ages were possible, a total of 348 measurements were taken. EHR in dated human embryos shows an increase up to 63 postmenstrual days or 22 mm greatest length. Thereafter a steady decrease of EHR was noted. Maximal EHR is reached when morphological development of the embryonic heart is completed. Furthermore, we examined 27 embryos with low EHR compared with greatest embryonic length. All of these ended in missed abortion within the embryonic period. According to our data the increase of EHR parallels the morphological development of the embryonic heart. Decline of EHR afterwards is interpreted as a functional adaption to muscular development of the heart.

Female↗
PubMed1993

[Teratoma of the umbilical cord. Case report with literature review].

A rare case of teratoma of the umbilical cord is reported. It is differentiated from acardius amorphus and compared with the nine cases reported in the literature since the first description in 1878. The clinical consequences for pregnancy of the tumour's influence on the circulation are discussed. For the first time, non-radioactive in situ hybridization of the interphase nucleus was performed in a teratoma of the umbilical cord. The results are presented and different histogenetic pathways, e.g. parthenogenetic origin of the teratoma, are debated.

Cell Transformation, Neoplastic↗