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Biomedical subjects

R Bald

Publications and source records attributed to R Bald.

At least 73 records · Page 4Linked to original sources
PubMed1988

Prenatal diagnosis and management in fetuses with cystic hygromata colli.

We report on 45 fetuses with prenatally diagnosed bilateral cystic hygromata colli by ultrasound. Two of the 45 cases involved a twin pregnancy with only one fetus showing hygromata colli. In 2 cases there was only isolated hygromata colli. The other 43 cases showed the signs of non-immune hydrops fetalis. The cytogenetic findings were: 9 fetuses with Turner syndrome, 1 fetus with Turner mosaicism, 1 fetus with trisomy 18, 6 fetuses with trisomy 21, 12 fetuses with normal karyotype, and 16 fetuses with a failed chromosome culture. In fetuses with Turner syndrome and normal karyotype the sonographic findings were similar: massive bilateral hygromata colli, substantial fluid accumulations in skin and body cavities, oligohydramnios and intra-uterine growth retardation. In the cases with trisomy 21, the relative size of the hygromata colli was smaller. Intra-uterine growth retardation and oligohydramnios were not observed. The sole survivor of our group (elective pregnancy interruption: 30 cases; intra-uterine death: 14 cases) (karyotype: 46,XY) presented sonographically with massive ascites, a moderate cystic hygroma, and appropriate fetal development, and a normal amniotic fluid quantity. These findings are analysed in order to provide recommendations for prenatal diagnosis, prenatal management and genetic counselling of the couples concerned.

Adult↗
PubMed1988

[Non-immunologically-induced hydrops fetalis in complete atrioventricular block of the fetus. A summary of 11 prenatally diagnosed cases].

In 11 of 21 fetuses with prenatally diagnosed complete heart block, congestive heart failure with signs of non-immune hydrops fetalis was seen. In all 11 fetuses, cardiac malformations were present: complete atrioventricular canal with levocardia, situs inversus viscerum, and polysplenia: 5 cases; tricuspid atresia with situs inversus viscerum, endocardial fibroelastosis, common atrium with aortic valve atresia, hypoplastic left heart, atrial septal defect of secundum type: one case each. All these cardiac malformations can also cause intrauterine heart failure without heart block except hypoplastic left heart and atrial septal defect. A review of the literature confirms, that only the association between complete heart block and cardiac malformation--in particular AV-canal and endocardial fibroelastosis--can cause an intrauterine congestive heart failure, whereas in the case of fetal complete heart block without cardiac malformation or with prenatally hemodynamically insignificant cardiac malformations--in particular "corrected" transposition of great arteries--a congestive heart failure is rare.

Echocardiography↗
PubMed1988

[2-dimensional color-coded fetal Doppler echocardiography--its value in prenatal diagnosis].

105 fetuses between 16 and 38 weeks of gestation were studied by fetal echocardiography using color-coded two-dimensional Doppler-echocardiography (2-DDE). Two-dimensional, M-mode, and spectral-Doppler analyses were also performed. In 11 fetuses, structural and/or functional abnormalities were detected. Abnormalities were correctly excluded in all other fetuses. The advantages of the 2-DDE are, in particular: rapid screening for flow abnormalities in the fetal heart and, thus, shortening of the Doppler-examination time; furthermore, a rapid diagnosis of valvular regurgitation, valvular stenosis and abnormal shunting of blood across the interatrial and interventricular septa; the diagnosis of complex congenital heart defects is facilitated by and, in certain case, only possible using 2-DDE.

Blood Flow Velocity↗
PubMed1988

[Fetal atrial flutter in complete atrioventricular canal and trisomy 18].

Fetal supraventricular tachyarrhythmias are very rarely associated with congenital heart diseases. Usually a circus movement (= reentry), often associated with a preexcitation, and occasionally an atrial ectopic focus are suggested as the pathophysiologic mechanisms of supraventricular tachyarrhythmias. In the reported case - atrial flutter, complete common atrioventricular canal with fetal trisomy 18 - the atrial flutter was probably provoked by the dilatation of the atria due to the regurgitation of both atrioventricular valves. This case indicates the need for a detailed echocardiographic examination (using two-dimensional, M-mode, and Doppler-echocardiography) in each case of fetal tachyarrhythmias in order to exclude associated cardiac defects, possibly in association with a chromosomal anomaly.

Adult↗
PubMed1988

Direct intrauterine fetal treatment of fetal tachyarrhythmia with severe hydrops fetalis by antiarrhythmic drugs.

In cases of non-immune hydrops fetalis caused by tachyarrhythmias, the transplacental passage of antiarrhythmic drugs may be hampered. When this is proven by fetal blood sampling in cases of tachyarrhythmia refractory to transplacental treatment, additional administration of antiarrhythmic drugs into the fetus is necessary and seems to improve the results. Although injections of antiarrhythmic agents in fetal ascites are also highly effective, intravascular administration by sonographic guidance is to be preferred. Then, simultaneous measurements of fetal and maternal drug levels are possible for the evaluation of pharmacokinetics and for monitoring the antiarrhythmic therapy.

Anti-Arrhythmia Agents↗
PubMed1988

Intrauterine therapy of fetal tachyarrhythmias: intraperitoneal administration of antiarrhythmic drugs to the fetus in fetal tachyarrhythmias with severe hydrops fetalis.

In cases of fetal tachyarrhythmia with congestive heart failure accompanied by signs of non-immune hydrops fetalis, the transplacental treatment of the fetus with antiarrhythmic agents by administration of drugs to the mother is only rarely successful. In the two cases reported, the cardioversion of a supraventricular tachycardia to a sinus rhythm or a constant 2:1 AV conduction block to a 1:1 AV conduction with atrial flutter could only be achieved after additional antiarrhythmic treatment directly administered to the fetus using ultrasound guidance. Drugs used include: beta-methyldigoxin, verapamil, propafenon, and they were administered according to the dosing amounts for intravascular injections. This was carried out 12 times in case 1 by the intraperitoneal route into the fetal ascites and twice in case 2. This led in both cases to varying durations of a sustained sinus rhythm after 5-15 minutes. This technically relatively simple procedure affords the option of rapidly achieving high concentrations, even when antiarrhythmic agents are administered which do not adequately cross the placenta. This direct treatment is indicated in cases of tachyarrhythmia with advanced signs of non-immune hydrops fetalis as a supplement to the high-dose transplacental therapy using antiarrhythmic agents.

Adult↗
PubMed1987

DNA structure in which an adenine-cytosine mismatch pair forms an integral part of the double helix.

Extensive studies using one- and two-dimensional 1H NMR at 500 MHz revealed that the oligonucleotide d(CGCCGCAGC) in solution at 5 degrees C forms a double helix under conditions of high salt (500 mM in NaCl, 1 mM sodium phosphate), low pH (pH 4.5), and high DNA concentration (4 mM in duplex). The presence of very strong nuclear Overhauser effects (NOEs) from base H8/H6 to sugar H2',H2" and the absence of NOE from base H8/H6 to sugar H3' suggested that the oligomer under these solution conditions forms a right-handed B-DNA double helix. The following lines of experimental evidence were used to conclude that C4 and A7 form an integral part of the duplex: (i) the presence of a NOESY cross-peak involving H8 of A7 and H8 of G8, (ii) the presence of a two-dimensional NOE (NOESY) cross-peak between H6 of C3 and H6 of C4, (iii) base protons belonging to C4 and A7 forming a part of the H8/H6---H1' cross-connectivity route, and (iv) the pattern of H8/H6---H2',H2" NOESY cross-connectivity based upon a B-DNA model requiring that both C4 and A7 form an integral part of the duplex. The possibility of an A-C pair involving H bonds was also examined. Two possible structural models of the duplex at pH 4.5 are proposed: in one model A-C pairing involves two H bonds, and in the other A-C pairing involves a single H bond.

Adenosine↗
PubMed1987

DNA hairpin structures in solution: 500-MHz two-dimensional 1H NMR studies on d(CGCCGCAGC) and d(CGCCGTAGC).

A hairpin structure contains two conformationally distinct domains: a double-helical stem with Watson-Crick base pairs and a single-stranded loop that connects the two arms of the stem. By extensive 1D and 2D 500-MHz 1H NMR studies in H2O and D2O, it has been demonstrated that the DNA oligomers d(CGCCGCAGC) and d(CGCCGTAGC) form hairpin structures under conditions of low concentration, 0.5 mM in DNA strand, and low salt (20 mM NaCl, pH 7). From examination of the nuclear Overhauser effect (NOE) between base protons H8/H6 and sugar protons H1' and H2'/H2", it was concluded that in d(CGCCGCAGC) and d(CGCCGTAGC) all the nine nucleotides display average (C2'-endo,anti) geometry. The NMR data in conjunction with molecular model building and solvent accessibility studies were used to derive a working model for the hairpins.

DNA↗
PubMed1987

[Supraventricular tachycardia of the fetus in the 3d trimester of pregnancy following persistent supraventricular extrasystole].

Persistent supraventricular extrasystoles are antepartally, intrapartally and postpartally the most frequent form of arrhythmias, and do not cause fetal congestive heart failure (hydrops fetalis). The premature beats often disappear spontaneously prenatally, but in most cases within the first two weeks of life. The extremely rare observation of the occurrence of a supraventricular tachycardia in the 37th week of gestation in a fetus with persistent supraventricular extrasystoles from the 20th week of gestation onward and with a postnatally diagnosed Wolff-Parkinson-White syndrome is described. Because of the importance of this complication of supraventricular extrasystoles (a supraventricular tachycardia of the fetus can cause a cardiac failure with hydrops fetalis and eventually intrauterine death), it is important that all fetuses with supraventricular extrasystoles be closely monitored by frequent observation of the fetal heart rate using ultrasound (M-mode-echocardiography), cardiotocography and auscultation. Postpartally a cardiologic examination of these newborn infants is necessary, particularly in order to exclude the presence of a preexcitation.

Cardiac Complexes, Premature↗
PubMed1987

Protein analysis in amniotic fluid and fetal urine for the assessment of fetal renal function and dysfunction.

Micromolecular proteins (molecular weight less than 68 kD) in amniotic fluid are assumed to be derived largely from fetal urinary excretion and therefore may reflect fetal kidney function and maturation. Microprotein concentrations in amniotic fluid, neonatal urine and urine of fetuses with bilateral urinary tract dilation were analyzed using microgradient gel electrophoresis to separate proteins according to their molecular size. Alpha-1-microglobulin and beta 2-microglobulin were assayed as singular micromolecular marker proteins. Microproteins in amniotic fluid decreased progressively with advancing gestation during the 3rd trimester. Micromolecular protein concentrations in the first postnatal urine of healthy infants born prematurely or at term were similar to those in amniotic fluid of corresponding fetal age and yielded an identical developmental pattern. A strong correlation existed between the microprotein concentrations in amniotic fluid and fetal urine. It is concluded that fetal urinary production is the main determinant for the microprotein content of amniotic fluid and that a major fetal pathway exists for the intrauterine metabolism of these proteins. The 3rd trimester decrease in amniotic fluid seems to be dependent on the increasing reabsorption capacity of proximal tubular cells representing morphological and functional kidney maturation. The exact diagnostic value of microprotein analysis for the assessment of disturbed fetal kidney function has still to be defined by further investigation.

Alpha-Globulins↗
PubMed1983

5'-terminal caps of snRNAs are accessible for reaction with 2,2,7-trimethylguanosine-specific antibody in intact snRNPs.

Immune precipitation assays with antibodies specific for 2,2,7-trimethylguanosine (m2,2,7(3)G) have been used to study the accessibility of the 5'-terminal m2,2,7(3)G-containing caps of eucaryotic small nuclear RNAs (snRNAs) either as naked RNAs or in intact small nuclear ribonucleoprotein (snRNPs). The antibody selectively precipitates snRNA species U1a, U1b, U2, U4, and U5 from total deproteinized RNA isolated from Ehrlich ascites cells. Binding by the antibody occurs via the m2,2,7(3)G moiety of the snRNAs' caps, since complex formation with the antibody can be completely abolished by excess nucleoside m2,2,7(3)G. The specificity of the antibody is further demonstrated by the complete absence of reaction with deproteinized snRNA species U6, the 5' terminus of which does not contain m2,2,7(3)G. Most importantly, the cap structures of the snRNAs U1a, U1b, U2, U4, and U5 are also accessible for anti-m2,2,7(3)G IgGs when intact snRNPs are reacted with the antibody. In this case, snRNP species U6 is coprecipitated, suggesting that there are intermolecular interactions between this and other snRNPs. Our data demonstrate that the 5'-terminal regions of the above snRNAs are not protected by the snRNP proteins. This finding is of special interest for snRNP species U1, and is discussed in terms of a model which proposes that the 5'-terminal region of U1 participates in the proper alignment of splice junctions in eucaryotic pre-mRNAs (Lerner, M. R., Boyle, J.A., Mount, S.M., Wolin, S.L., and Steitz, J. A. (1980) Nature (Lond.) 283, 220-224).

Animals↗
PubMed1982

Isolation and characterization of rabbit anti-m3 2,2,7G antibodies.

Antibodies specific for intact 2,2,7-trimethylguanosine (m3 2,2,7G) were induced by immunization of rabbits with a nucleoside-human serum albumen (HSA) conjugate. Competition radioimmunoassay showed that the antibody distinguishes well between intact m3 2,2,7G and its alkali-hydrolysed form (m3 2,2,7G*). Antibody specificity is largely dependent on the presence of all three methyl groups in m3 2,2,7G: none of the less extensively methylated nucleosides m7G, m2G and m2 2,2G is able to compete efficiently with the homologous hapten. Little or no competition was observed with m1G, m1A, m6A, m5U and each of the four unmodified ribonucleosides. Binding studies with nucleoplasmic RNAs from Ehrlich ascites cells suggest that the antibody reacts specifically with the m3 2,2,7G-containing cap structure of the small nuclear U-RNAs (U-snRNAs). Thus the antibody should be a valuable tool for studying the role of the 5'-terminal regions of the U-snRNAs of eucaryotic cells.

Animals↗
PubMed1982

[Ultrasound mammography: development, current status and limits].

Starting with a survey of the historical development of ultrasound-mammography the current status of this method within other diagnostic procedures of the breast is defined. Basing on over 1000 examinations since 1975 we report the sonographic possibilities in demonstrating different normal and pathologic breast structures. Pathologic structures are: Dudectasy, Cysts, Mastitis, Fibroadenoma, Carcinoma and Gynaecomasty. Own results are reported and the future of ultrasound mammography is discussed.

Adolescent↗
PubMed1981

Localization of the puromycin binding site on the large ribosomal subunit of Escherichia coli by immunoelectron microscopy.

By using immunoelectron microscopy, we have localized the binding site on 50S Escherichia coli ribosomal subunits for puromycin, an antibiotic that interacts with the ribosomal peptidyltransferase center. This was achieved by affinity-labeling 50S subunits with N-bromoacetyl puromycin and treating the labeled subunits with an antibody specific for the N6,N6-dimethyladenosine moiety of puromycin. The position of the puromycin binding site was then revealed by localizing the attachment sites of the IgG molecules on the surfaces of the 50S subunits under the electron microscope: it was located at the interface between the subunits, on and around the wider lateral protuberance of the 50S subunit. This localizes directly the peptidyl transferase center on the surface of the large ribosomal subunit.

Binding Sites↗
PubMed1978

Restriction and modification in Bacillus subtilis. Localization of the methylated nucleotide in the BsuRI recognition sequence.

Calf thymus DNA was methylated in vitro with cell extracts of Bacillus subtilis OG3R (r+m+) and S-adenosyl[Me-3H]methionine. After depurination of the [3H]methylated DNA, the analysis of the pyrimidine dinucleotides revealed the following positions of the methylated nucleosides (indicated by an asterisk) within the BsuRI recognition sequence: 5' dG--dG--dC--dC dC--dC--dG--dG 5'.

Bacillus subtilis↗