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Biomedical subjects

M Jung

Publications and source records attributed to M Jung.

At least 289 records · Page 16Linked to original sources

Combined cytogenetic techniques and non-fluorescent Y. Cytologic evidences of dic(Yp)(q11) in a previously interpreted 46,X,Yq-.

mos 45,X/46,X,Y with no bright fluorescence was studied in 4 patients presenting variable phenotypes, from Turner's syndrome, with or without virilization, to ambiguous external genitalia, with combined cytogenetic techniques. G-11 staining demonstrated, in all cases, that the abnormal Y was a dic(Yp). Considerations about the possibility that some of the 46,X,Yq-males attending infertility clinics may be examples of dic(Yp) are made.

Adolescent↗

Concordance of experimentally mapped or predicted Z-DNA sites with positions of selected alternating purine-pyrimidine tracts.

The recent electronmicroscopic and biochemical mapping of Z-DNA sites in phi X174, SV40, pBR322 and PM2 DNAs has been used to determine two sets of criteria for identification of potential Z-DNA sequences in natural DNA genomes. The prediction of potential Z-DNA tracts and corresponding statistical analysis of their occurrence have been made on a sample of 14 DNA genomes. Alternating purine and pyrimidine tracts longer than 5 base pairs in length and their clusters (quasi alternating fragments) in the 14 genomes studied are under-represented compared to the expectation from corresponding random sequences. The fragments [d(G X C)]n and [d(C X G)]n (n greater than or equal to 3) in general do not occur in circular DNA genomes and are under-represented in the linear DNAs of phages lambda and T7, whereas in linear genomes of adenoviruses they are strongly over-represented. With minor exceptions, potential Z-DNA sites are also under-represented compared to random sequences. In the 14 genomes studied, predicted Z-DNA tracts occur in non-coding as well as in protein coding regions. The predicted Z-DNA sites in phi X174, SV40, pBR322 and PM2 correspond well with those mapped experimentally. A complete listing together with a compact graphical representation of alternating purine-pyrimidine fragments and their Z-forming potential are presented.

Animals↗

The conformation of single stranded oligonucleotides and of oligonucleotide-oligopeptide complexes from their rotation relaxation in the nanosecond time range.

The conformation of single stranded oligonucleotides is analysed by measurements of their rotation time constants. The oligomers are aligned to some degree by short electric field pulses; after pulse termination the transition to a random orientation is followed by measurements of the linear dichroism. An efficient deconvolution procedure is developed for evaluation of the experimental data obtained in the ns-time range. The increase of rotation time constants observed for chain lengths in the range from 14 to 22 residues are interpreted according to a weakly bending rod model providing a persistence length and a Stokes' diameter. The Stokes' diameters obtained for ribo- and deoxyriboadenylates are about 13A, in approximate agreement with the expectation for a single stranded helix. The persistence length L = 53A corresponding to approximately 16 nucleotide residues found for riboadenylates at 2 degrees C appears to reflect relatively strong stacking interactions at this temperature. However, a comparison with the average length of stacked residues evaluated from available thermodynamic parameters of base stacking indicate that unstacked residues are not completely flexible. Apparently the ribose-phosphate chain provides an essential contribution to the stiffness of oligomers and polymers, even when the bases are unstacked. Addition of 100 microM Mg2+ leads to an increase of the persistence length to 88A. Corresponding measurements with deoxyriboadenylates show a slightly lower value of the persistence length than that found for riboadenylates. Addition of LysTrpLys and LysTyrLys to A(pA)19 leads to an increase of the rotation time constant, which corresponds approximately to a length increment by one residue per bound peptide. Since controls performed with LysLeuLys do not show any similar effect, the increase of the time constants induced by LysTrpLys and LysTyrLys is attributed to intercalation of the aromatic amino acids.

Chemical Phenomena↗

G-11 staining in Turner's syndrome with mos 45,X/46,X,r(?).

Mos 45,X/46,X,r(?) in 4 patients with Turner's syndrome and no signs of virilization, and in one pair of monozygotic twins, one of them with clitoral hypertrophy, was studied using combined cytogenetic techniques and specially G-11 staining for the characterization of the X or Y origin of the rings. In all 6 patients the ring was G-11 positive, attesting its Y origin. Both twins were operated and bilateral streak gonads with a bilateral nodule of testicular tissue were found. Similar small rings were also studied in one patient with mos 46,XX/46,X,r(X) and in one nonvirilized Turner's syndrome patient with a larger ring; in these two cases the ring was G-11 negative. It seems that the small rings occasionally found in Turner's syndrome are more frequently from Y origin and therefore prophylactic gonadectomy should be considered.

Adolescent↗

Monozygotic twins with Turner's syndrome and mos 45,X/46,X,r,(Y).

A pair of monozygotic twins with Turner's syndrome was studied using combined cytogenetic techniques and a mos 45,X/46,X,r(Y) was demonstrated in both. One of the twins presented clitoral hypertrophy. Surgery was performed and uterus, bilateral Fallopian tubes, bilateral epididymis and bilateral streak gonads with a small nodule of testicular tissue containing numerous seminiferous tubules were found in both.

Adolescent↗

Structural family therapy: its application to Chinese families.

In summary, it can be stated that structural family therapy, for a variety of reasons, offers an appropriate treatment model for dysfunctional Chinese families. Since the family, not the individual, is the more important unit in Chinese culture, the model offers the opportunity for the total family to participate in changing dysfunctional individual and family patterns. The model focuses upon structure, which is the essence of the Chinese family. In addition, it is problem- and growth-oriented, creates a nondefensive atmosphere in which family members can change, and works toward helping family members improve communication and modify behavior. It is important to stress that it does not focus upon helping family members make significant changes in their value system. Furthermore, the model can be applied to most problem areas, because it is assumed that the presenting problem is reinforced by family structure and repetitive patterns. Consequently, family interactional patterns that reinforce the presenting problems are the major focus of the treatment. Finally, the model allows for the utilization of theories and practice principles of other clinical approaches. Structural family therapists assume the role of authority figures who are experts in family therapy. They view the family within the context of its environment, are sensitive to the cultural norms of the group with which they are working, and utilize supportive services as an integral part of treatment. More important, therapists believe in the power of families to make changes and work toward helping them become involved in a new process of interaction that will lead to satisfactory changes.

Acculturation↗

[Implantation of ultra thin naso-duodenal and naso-jejunal tubes for feeding].

Enteral nutrition through filiform naso-duodenal or naso-jejunal tubes with homogeneous low molecular nutritional solutions has a rather important place in therapy of different conditions; endoscopy can help to introduce these tubes into the intestinal tract in the following situations: A leak in the upper gastrointestinal tract, which may occur after surgical resections of the esophagus or stomach, or which may occur in rare cases after bouginage or after diagnostic procedures can be passed by with an ultrathin tube until it is healed of. Patients with stenotic lesions of the esophagus or the cardia, which can not be treated by surgery or conservative procedures like pertubation and dilation can be fed enterally if it is possible to move the tube beyond the stenosis. Patients with neurogenic swallowing dysfunction of different origine can be fed during long periods of time through such filiform naso-enteral tubes successfully and reach a perfect nutritional state. In acute treatment of Crohn's disease and other inflammatory intestinal diseases enteral nutrition through tubes is an essential therapeutic procedure.

Deglutition Disorders↗

[Poisoning with clonidin hydrochloride in children and adults].

In this study clinical findings are presented of 31 patients with clonidinee intoxication and the therapeutic measures taken in these cases are discussed. In toddlers poisoning is seen after ingestion of a single tablet of 150 micrograms clonidine, whilst in adults poisoning may occur already at a dosage just exceeding the therapeutic limit, which is subject to wide individual variation (1 to 3 tablets). Primary elimination procedures must be instituted at these dosages, but, because of the rapid absorption of clonidine, gastric lavage and induced emesis provide no benefit to patients with complete symptomatology or those who took the overdose several hours before. Chlorpromazine-like effects, hypotension and bradycardia proved to be the outstanding features. Respiratory depression, disturbances of myocardial conduction or hypertension were less frequent. Symptoms lasted for a mean of 15.5 +/- 8.6 hours, with a range of 4 to 36 hours. Fluid therapy and, as necessary, dopamine for hypotension, phentolamine for hypertension and atropine for bradycardia caused prompt improvement in addition to essential measures such as meticulous control of respiratory function, body temperature and of ECG changes. There was no need to implement the central clonidine antagonist, tolazoline in any of these cases.

Adolescent↗

Inhibition of histamine biosynthesis and gastric function in the rat: effect on pentagastrin-induced gastric acid secretion.

A very simple and rapid method to measure gastric acid secretion in the conscious unoperated fasted rat is reported. Antisecretory activity of cimetidine and hypersecretory activity of pentagastrin are detected by this procedure. Pentagastrin induces gastric acid secretion and causes an increase by 2-fold in histidine decarboxylase activity. There is a delay between the increase of gastric acid output and the appearance of histidine decarboxylase activity. Co-administration of monofluoromethyl histidine, a specific irreversible inhibitor of histidine decarboxylase, does not modify the peak response to pentagastrin but shortens the duration of stimulation. We suggest from this data that histamine biosynthesis is needed for maintenance of elevated gastric acid secretion.

Animals↗

Stability decrease of RNA double helices by phenylalanine-, tyrosine- and tryptophane-amides. Analysis in terms of site binding and relation to melting proteins.

The amides of L-phenylalanine, L-tyrosine and L-tryptophane decrease the melting temperatures tm of poly(A)*poly(U) and poly(I)*poly(C) double helices at low concentrations (1 mM), whereas high concentrations finally lead to an increase of tm. This dependence of the tm-values upon the ligand concentration can be represented quantitatively by a simple site binding model, providing binding parameters for the interaction between the amides and the nucleic acids both in the double- and the single-stranded conformation. According to these data the affinity to the single strands is higher than that to the double strands and increases in the series Phe less than Tyr less than Trp. The binding constants decrease with increasing salt concentration as expected for an interaction driven by electrostatic attraction. However, part of the interaction is also due to stacking between the aromatic amides and the nucleic acid bases. The present results indicate a direct correlation between the presence of aromatic amino acids at the binding site of helix destabilising proteins and the properties of simple derivatives of these amino acids. Furthermore the results suggest that very simple peptides containing aromatic amino acids served as a starting point for the evolution of helix destabilising proteins.

Chemical Phenomena↗

Electric properties and structure of DNA-restriction fragments from measurements of the electric dichroism.

The electric dichroism of 17 homogeneous DNA fragments, ranging in size from 43 to 4362 base-pairs, has been analyzed in high electric fields. The orientation of the small fragments can be described in terms of an induced dipole moment, whereas the large fragments are oriented according to a constant dipole mechanism. In the intermediate size range, DNA orients according to an induced dipole mechanism at low field strengths and according to a constant dipole mechanism at high field strengths. From these observations we propose an orientation mechanism with a saturating induced dipole. The induced dipole observed at low field strengths is saturated at a field strength Eo within a transition range Em to give a constant dipole moment at high field strengths. These parameters together with the polarizability and the limit reduced dichroism are evaluated by a least-squares analysis of the experimental data. Eo and Em are found to decrease with increasing chain length from Eo approximately 40 kV/cm (Em approximately 14 kV/cm) at 65 base-pairs to 10 kV/cm (6 kV/cm) at 194 base-pairs. The polarizability is found to increase with the square of the chain length, whereas the saturated dipole increases with chain length N at low N and goes to a limit value at high N. The temperature dependence of the orientation parameters is found to be very small. The values obtained for the limit dichroism are between -1.0 and -1.3 for chain lengths between 60 and 1000 base-pairs, whereas values around -1.4 are observed at chain lengths greater than 1000 base-pairs. These data indicate that electric fields extend the contour of DNA strands at high chain lengths from a weakly bent to a more linear form. The variations of the limit dichroism observed for short fragments suggest sequence-dependent differences in the secondary structure of the helix. The experimental results are compared with numerical calculations based on simple polyelectrolyte models. For short fragments the magnitude of several electrochemical parameters can be adequately explained by a polarization of the ion cloud around the DNA molecules. However, these polyelectrolyte models do not adequately describe the observed chain length dependence of the orientation phenomena.

Base Composition↗

[Serodiagnosis of human Yersinia infections. Preliminary results].

Preliminary data are reported on experience with newly developed complement-fixing (CF) antigens prepared from cultures of type 3 and type 9 Yersinia enterocolitica and from Yersinia pseudotuberculosis. Antigens were immunologically potent and not anti-complementary, thus making it possible to obtain satisfactory serologic tests. The results may be summarized as follows: 1. Yersinia CF antigens do not react with sera from healthy blood donors. There was only one low titer reaction with type 9 antigen among more than 300 serum samples tested. 2. There was a high degree of correlation between results of the agglutination tests and those obtained by CF. 3. There is no cross-reactivity by CF among the three Yersinia antigens if human sera are tested. A complete crossing was, however, obtained between type 9 Yersinia and Brucella abortus. 4. Hyperimmune sera frequently showed marked cross-reactivities in both CF and agglutination tests. 5. Human sera positive for various Salmonellae do not react in the CF tests with Yersinia antigens. It is felt that the new CF antigens may become an important tool for the detection of antibodies against Yersinia enterocolitica in the diagnosis of infectious diseases.

Antibodies, Bacterial↗

Recent biosynthetic studies on beta-lactam antibiotics.

Recent experimental observations on the cell-free formation of penicillins and cephalosporins in protoplast lysates from C. acremonium are described. Conversion of radiolabelled penicillin N into deacetoxycephalosporin C is described. A proposal is made about the general types of mechanism involved in these conversions.

Acremonium↗