[The incidence of silent myocardial ischemia]

Retrospectively evaluated was the patient population of the years 1982 to 1988 which underwent ergometric investigations concerning the appearance of silent myocardial ischaemias. In 256 reactions of exercise ischaemia of patients with definitive coronary disease in 47 cases angina pectoris appeared (18.4%). Reactions of ischaemia in a large area of the breast wall showed, compared with a small area of ischaemia, a significantly higher proportion of symptomatic episodes (34.3% vs 13.0%, P less than 0.05). Ergometric exercises lying below the norm of age were more frequently accompanied by symptomatic ischaemias than ischaemic reactions, which only appeared in a good area of performance (26.0% vs 11.4%, P less than 0.05). In addition to this more anginose complaints were found in patients, whose ischaemic reaction was accompanied by an insufficient frequency response (28.1% vs 9.8%, P less than 0.05).

Chemical and enzymatic analysis of covalent bonds between peptides and chromosomal DNA

DNA from Ehrlich ascites tumor (EAT) cells and from human placenta was examined for covalent bonds between hydroxy amino acid residues in peptides and nucleotide phosphate groups. The residual proteinaceous material in highly purified DNA was radiolabelled with 125Iodine and the linking-groups between peptides and nucleotides released by combined protease and nuclease treatment were investigated with respect to their chemical and enzymatic stabilities. The residual nucleotide(s)-peptide(s) fraction from DNA isolated after prolonged alkaline cell lysis and phenol extraction contains mainly alkali and acid-stable but phosphodiesterase-sensitive peptide-nucleotide complexes which indicates phosphodiesters between tyrosyl residues in peptides and nucleotide phosphates. In contrast, the linking-group fraction from DNA isolated under native conditions contains additional peptide components. (a) Phospho-peptides that co-purify with DNA but that are not covalently bound to nucleotides. (b) A fraction of peptides that is released from nucleotides by alkali in a time and concentration-dependent reaction. Evidence is presented indicating that the latter fraction involves phospho-triesters between hydroxy amino acid residues in peptides and internucleotide phosphates. The phosphodiesters between hydroxy amino acids and nucleotide phosphates representing the predominant class of peptide-nucleotide complexes in alkali-denatured DNA are most likely side products of peptide-nucleotide phospho-triester hydrolysis.

Indirect Na+ dependency of urate and p-aminohippurate transport in pig basolateral membrane vesicles

Membrane vesicles were used to study the basolateral transport of urate and p-aminohippurate (PAH) in the proximal tubule of the pig kidney. Consistent with a cooperation between a Na(+)-2-oxoglutarate cotransporter and a 2-oxoglutarate-urate or a 2-oxoglutarate-PAH exchanger, urate and PAH uptakes were stimulated in presence of extravesicular 2-oxoglutarate when an inwardly directed Na+ gradient was applied. Both transports exhibited, however, different characteristics. The optimal 2-oxoglutarate concentration for stimulating uptakes was 10 microM for PAH and 150 microM for urate. Extravesicular chloride was required to observe a stimulation of PAH uptake but not of urate uptake. Transports of both PAH and urate exhibited different affinity sequences for various organic anions. Stimulated PAH uptake was inhibited by probenecid greater than cold PAH greater than urate = pyrazinoate greater than lactate, whereas stimulated urate uptake was inhibited by probenecid greater than cold urate greater than PAH and not by pyrazinoate or lactate. These results are consistent with independent transport processes for urate and PAH in pig basolateral membrane vesicles, both being indirectly driven by an inwardly directed Na+ gradient.

Isoflavonoid-inducible resistance to the phytoalexin glyceollin in soybean rhizobia

The antibacterial effect of the soybean phytoalexin glyceollin was assayed using a liquid microculture technique. Log-phase cells of Bradyrhizobium japonicum and Sinorhizobium fredii were sensitive to glyceollin. As revealed by growth rates and survival tests, these species were able to tolerate glyceollin after adaptation. Incubation in low concentrations of the isoflavones genistein and daidzein induced resistance to potentially bactericidal concentrations of glyceollin. This inducible resistance is not due to degradation or detoxification of the phytoalexin. The inducible resistance could be detected in B. japonicum 110spc4 and 61A101, representing the two taxonomically divergent groups of this species, as well as in S. fredii HH103, suggesting that this trait is a feature of all soybean-nodulating rhizobia. Glyceollin resistance was also inducible in a nodD1D2YABC deletion mutant of B. japonicum 110spc4, suggesting that there exists another recognition site for flavonoids besides the nodD genes identified so far. Exudate preparations from roots infected with Phytophthora megasperma f. sp. glycinea exhibited a strong bactericidal effect toward glyceollin-sensitive cells of B. japonicum. This killing effect was not solely due to glyceollin since purified glyceollin at concentrations similar to those present in exudate preparations had a much lower toxicity. However, glyceollin-resistant cells were also more resistant to exudate preparations than glyceollin-sensitive cells. Isoflavonoid-inducible resistance must therefore be ascribed an important role for survival of rhizobia in the rhizosphere of soybean roots.

Circadian pattern of large neutral amino acids, glucose, insulin, and food intake in anorexia nervosa and bulimia nervosa

Insulin, glucose, and large neutral amino acids (LNAA) were studied in 10 patients with anorexia nervosa, 13 patients with bulimia nervosa, and 15 healthy controls. Blood samples were collected at hourly intervals during the day and at two-hour intervals during the night over a 24-hour period. Ad libitum caloric and relative carbohydrate intake was significantly reduced in the anorectic and bulimic patients. Elevated concentrations of beta-hydroxybutyric acid (BHBA) were seen in the bulimic group, and low triiodothyronine (T3) concentrations in the anorectic group. Mean plasma glucose and insulin concentrations were significantly lowered in both groups. The tryptophan (Trp) to LNAA ratio was reduced in anorectic, but not in bulimic patients. These findings suggest that Trp influx into the brain is reduced in anorectic patients, possibly impairing central serotonergic function.

Nucleotide sequence of the murine prothymosin alpha cDNA and its deduced primary and secondary protein structure

Searching for proliferation-related and cell cycle phase-specific genes we detected a full-length cDNA for the murine prothymosin alpha mRNA which was sequenced on the DNA level. The amino acid sequence deduced from the nucleotide sequence shows a high degree of positional identities with prothymosin alpha from man and rat. However, the minor differences in the primary structures largely influence predictions for the secondary structures of prothymosin alpha from different species. These differences in the secondary structure could explain the differences of activity of prothymosin alpha from different origin in immuno-protection assays.

Murine cDNAs coding for the centrosomal antigen centrosomin A

Screening of an induced Ehrlich ascites cell-derived lambda gt11 cDNA library with an antibody (GP1), immunoreacting specifically with centrosomal antigen(s) of interphase and mitotic cells of different species, released a partial cDNA clone (lambda P10A) encoding the carboxy-terminal section of a centrosome-specific antigen. This specificity of the clone lambda P10A could be verified by lacZ-directed antigen expression from Escherichia coli Y1089 lysogenized with the recombinant phage lambda P10A and subsequent production of centrosome-specific antibodies by means of the recombinant antigen. Using the lambda P10A insert as a probe, two types of cDNA clones were identified in a lambda gt10 cDNA library by plaque-hybridization. The inserts of PN1 type clones were 1.2 kb (kilobases) and those of PN5 type clones were 2.2 kb in length. The DNA sequence of a PN1 type clone revealed its full-length cDNA nature. The open reading frame of PN1 encodes a rather hydrophilic and highly charged 34.5 × 10(3) Mr polypeptide comprising short but apparently significant strings of 100% sequence identity with the major nuclear lamina polypeptides lamins A/C and lamin B. Restriction enzyme mapping of PN1 and PN5 inserts, cross-hybridization experiments and comparison of overlapping DNA sequences indicate that the 1.2 kb and 2.2 kb cDNAs code for the same 34.5 × 10(3) Mr polypeptide, termed centrosomin A. Western blots of Ehrlich ascites cell proteins show a second, larger GP1 antigen (centrosomin B) whose cDNA has not been cloned. It remains to be investigated whether centrosomin B is encoded by a second mRNA or whether it reflects an oligomeric or a postranslationally modified form of centrosomin A.

Random silent mutagenesis in the initial triplets of the coding region: a technique for adapting human glutathione reductase-encoding cDNA to expression in Escherichia coli

The introduction of random silent mutations into the 5'-coding region of a human cDNA as the basis for successful expression in Escherichia coli is demonstrated in four steps. (1) Plasmid pUB200 containing the pRpL promoters of phage lambda was found not to serve as an expression vector for a unchanged human glutathione reductase (hGR)-encoding cDNA. (2) When this cDNA was expressed in a two-cistron context using high-copy-number plasmids, recombinant protein was detected in low yield (0.03% of the total cell protein). (3) Silent mutations were introduced into the triplets coding for the N-terminal amino acids. When screening E. coli colonies transformed with expression plasmids containing cDNA mutants, we identified adapted clones that produced hGR in up to 70-fold higher yield than the clone containing the unchanged cDNA. Sequence analyses of adapted cDNA species revealed lower G + C contents in the modified regions, suggesting altered mRNA structures. (4) When the adapted cDNA sequences were recloned in the vector which had failed to express unchanged hGR cDNA in step 1, synthesis of recombinant protein was as high as in step 3. This means that the yield of expression for adapted cDNA was at least 1000-fold higher than for unchanged cDNA. In conclusion, random silent mutations introduced into the translation initiation region of cDNA might be a useful technique for designing sequence features which favour gene expression.

Transport of urate and p-aminohippurate in rabbit renal brush-border membranes

The mechanisms involved in urate and p-aminohippurate (PAH) transport in the rabbit renal brush-border membrane were investigated through study of membrane vesicles. Transport of [14C]urate and [3H]PAH was measured by a rapid filtration method. As previously reported by others, no OH(-)-PAH exchanger could be demonstrated by imposing an outwardly directed OH- gradient (pHin 7.4, pHout 6). In contrast, an OH(-)-lactate exchanger (or H(+)-lactate cotransport) was demonstrated. In the presence of valinomycin and an inwardly directed K+ gradient, both [14C]urate and [3H]PAH vesicle uptake were stimulated, demonstrating a potential-driven transport of these two anions. Probenecid, PAH, or cold urate decreased potential-driven urate uptake, suggesting that this transport was facilitated by a specific transport mechanism. The potential-driven urate transport described here may play a role in the second step of urate secretion in rabbits, because rate (or PAH) is transported across the brush-border membrane from the negative interior of the cell to the more positive omen.

Cloning and sequencing of mammalian glutathione reductase cDNA

The molecular cloning of a partial cDNA to mouse glutathione reductase mRNA and of a full-length cDNA to the mRNA of the human enzyme is described. An initial cDNA clone designated lambda GRM-B11 was isolated by plaque-screening of an induced mouse cDNA expression library in the lambda gt11 vector with a rabbit antibody probe to human glutathione reductase. 125Iodine-labelled whole anti-rabbit immunoglobulin was used as second antibody. EcoRI digestion of the lambda GRM-B11 clone released a 720-bp fragment which was identified as a partial mouse glutathione reductase cDNA by the following techniques. (a) Escherichia coli Y1089 lysogenized with lambda GRM-B11 could be induced to synthesize a recombinant polypeptide whose antigenicity to anti-(glutathione reductase) serum was established by SDS/polyacrylamide gel electrophoresis and subsequent immunoblotting. (b) The GRM-B11 sequence, recloned in the Bluescript vector to give the plasmid pGRM-B11, was found to code for a polypeptide consisting of 242 amino acid residues exhibiting 82% identities with the known amino acid sequence of the human glutathione reductase from position 77 to 318. The insert of the pGRM-B11 plasmid was used as a bona fide nucleic acid probe to screen mouse and human cDNA libraries prepared in the lambda gt11 or in the lambda gt10 vector. The first full-length cDNA clone (lambda GRH-Mev10) was identified in a human cDNA library based on RNA of human placental cells. Its insert was composed of three EcoRI fragments of 720, 613 and 336 bp. The three fragments were recloned in the Bluescript vector and sequenced. The largest fragment (pGRH-B) is colinear with the mouse sequence cloned in the pGRM-B11 plasmid. The fragment of intermediate size (pGRH-CT) comprises the 3' end of the mRNA and the poly(A) tail while the short fragment (pGRH-NT) corresponds to the 5' region of the mRNA. The amino acid sequence deduced from the nucleotide sequences of the three subclones is identical with the known sequence of the mature glutathione reductase from human erythrocytes in all 478 positions.

Differential screening of murine ascites cDNA libraries by means of in vitro transcripts of cell-cycle-phase-specific cDNA and digital image processing

Cell-cycle-phase-specific cDNA libraries were prepared in the lambda gt10 vector and in the in vitro transcription vector, pBluescript. Plaques of the cDNA libraries prepared in the lambda gt10 vector were differentially screened with (a) in vitro transcripts of the cell-cycle-phase-specific cDNAs cloned in the transcription vector and (b) with first-strand cDNA of mRNA from phase-synchronous cells. The results suggest that first-strand cDNA can be replaced, at least in prescreening experiments, by in vitro transcripts of representative cDNA libraries prepared in in vitro transcription vectors. The fractions of differential clones detected with in vitro transcripts (1.2%) and with first-strand cDNA (1%) were in the same order. Individual clones selected by differential hybridization with in vitro transcripts could be verified by differential hybridization with cell-cycle-phase-specific first-strand cDNA. This indicates that the pattern of stage-specific prevalences of cDNA clones is essentially retained during careful amplifications of large cDNA libraries. The application of in vitro transcripts of stage-specific cDNA for differential screening experiments is of interest in cases where the amount of biological material is either limited or difficult to prepare. It also allows standardization of the probes in repeated screening experiments. Three clones reflecting cell-cycle-phase-specific mRNA prevalences were chosen and analyzed on the sequence level. Two sequences with S-phase prevalences were identified. They code for elongation factor EF1 alpha and for glyceraldehyde-3-phosphate dehydrogenase, respectively. The third sequence reflects the first cDNA of a mRNA with significant prevalence in G2-phase cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Urate and p-aminohippurate transport in the brush border membrane of the pig kidney

The transport of urate and p-aminohippurate (PAH) across the pig renal brush border membrane was investigated using membrane vesicles. Compared to a pH equilibrium condition (pHin = 7.4; pHout = 7.4), an outwardly directed OH- gradient (pHin = 7.4; pHout = 5.8) stimulated markedly both lactate and pyrazinoate uptake with overshoots exceeding 2 times that of the steady state. In contrast, neither OH-/urate nor OH-/PAH exchange could be demonstrated. An outwardly directed Cl- gradient (Cl-in = 100 mM; Cl-out = 16.7 mM) increased 2.6-fold 15-sec PAH uptake compared to Cl- equilibrium (Cl-in = Cl-out = 100 mM) but this stimulation was due solely to an effect of membrane potential. Creation of an electropositive intravesicular space, by imposing an inwardly directed K+ gradient (K+in = 0 mM; K+out = 100 mM) in the presence of valinomycin, was very effective to drive uphill PAH and urate accumulation compared to the control condition (no valinomycin). Four-second potential-stimulated PAH uptake was saturable (Km, 0.8 mM; Vmax, 1.7 nmol/mg of protein x 4 sec). Different organic anions cis-inhibited both 4-sec potential-stimulated PAH and urate uptakes in a similar fashion. PAH and urate, moreover, decreased each other's accumulation. In countertransport experiments, PAH and urate uptakes were not significantly stimulated by trans-unlabeled substrate. These results are consistent with the presence, in the pig renal brush border membrane, of a mediated secretory pathway common for urate and PAH, which could be facilitated by the potential difference existing in vivo across the luminal membrane of the proximal tubule.

Site-specific location of covalent DNA-polypeptide complexes in the chicken genome

A nitrocellulose filter binding assay was applied to isolate and to analyze the fraction of chicken DNA fragments associated with residual nuclear polypeptides resistant to SDS/proteinase K treatment and phenol extraction. It is shown that the DNA-polypeptide complexes retained on nitrocellulose filters are located on a non-random sub-set of DNA sequences. (a) Southern analysis reveals that the fractions of DNA fragments from chicken erythrocytes and from hen oviduct cells associated with the resistant polypeptides have a lower sequence complexity than unfractionated DNA. Moreover, the retained DNA fractions from different cell types of the same species are highly homologous. (b) All DNA fragments of the transcriptionally active and inactive ovalbumin gene map in the DNA fraction passing the filters indicating that the tight DNA-polypeptide complexes are not remnants of transcription complexes. (c) By use of a genomic sub-set library prepared from DNA retained on filters, clones were isolated with sequences mapping specifically in the DNA fraction associated with the tight DNA-polypeptide complexes. The results are consistent with fixed covalent DNA-polypeptide complexes in the chicken genome whose location is essentially identical in different cell types of the same species and apparently determined by DNA signal-sequences.

Nucleotide sequence of the full-length mouse lamin C cDNA and its deduced amino-acid sequence

We have cloned and sequenced the cDNA comprizing the entire coding region and several hundred base-pairs of its flanks for the mouse nuclear envelope protein lamin C mRNA. The nucleotide sequence and the deduced amino-acid sequence of the mouse lamin C are compared with the previously published human lamin A/C sequences with respect to (a) the general organisation, (b) homologies, (c) predictions for the essential structural characteristics of lamins and (d) the localization of the most conserved region. Moreover, the mouse lamin C sequence presented allows the first intraspecies comparison between A/C-type and B-type lamins.

Peribacteroid membrane nodulin gene induction by Bradyrhizobium japonicum mutants

Seventeen translation products from Glycine max root mRNA precipitated with antiserum prepared against a peribacteroid membrane preparation from effective root nodules. Messenger RNA from fix (+) nodules coded for these 17 products plus 7 other nodule-specific polypeptides which bound to the antiserum. Of these 7 nodulins only 4 were present when nodules were infected with Bradyrhizobium japonicum 110 rif 15 2960, which induces the plant to produce 'empty' peribacteroid membranes. In nodules infected with B. japonicum strains inducing either very short-lived or defective peribacteroid membrane, only 5 or 6, respectively, of these nodulins could be detected.From these results we hypothesize that the microsymbiont is responsible for the production of at least 4 different signals leading to peribacteriod membrane formation by the plant.

Construction and quality of cDNA libraries prepared from cytoplasmic RNA not enriched in poly(A)+RNA

Poly(A)+RNA and cytoplasmic RNA of Ehrlich ascites tumor cells grown in vivo were used to study the quality and efficiency of cDNA synthesis. It was found that the rates of oligo(dT)-primed and unprimed reverse transcription were very similar in both cases. The size distributions of the cDNA strands prepared from unfractionated RNA reflected the size of cytoplasmic mRNA populations including a significant fraction of long molecules up to 6 kb. The fraction of cDNAs primed on rRNAs by oligo(dT) was found to be as low as 2-3%. Following second-strand synthesis by means of RNase H-induced nick translation by DNA polymerase I the overall yields in double-stranded cDNA were slightly higher when unfractionated cytoplasmic RNA was used as starting template. In repeated experiments we obtained an average yield of 2.2 micrograms of double-stranded cDNA when 70 micrograms of unfractionated cytoplasmic RNA was used as starting material. This amount of cDNA synthesized in one assay was sufficient to construct representative cDNA libraries in different vectors. Southern hybridizations of DNA isolated from cDNA libraries with various radiolabelled probes show that the libraries constructed from cDNA synthesized from cytoplasmic RNA not enriched in poly(A)+RNA contain a high ratio of full-length cDNA clones. The results suggest that representative cDNA libraries of high quality can be constructed without pre-isolation of poly(A)+RNA fractions.

Functional role of a highly repetitive DNA sequence in anchorage of the mouse genome

The major portion of the eukaryotic genome consists of various categories of repetitive DNA sequences which have been studied with respect to their base compositions, organizations, copy numbers, transcription and species specificities; their biological roles, however, are still unclear. A novel quality of a highly repetitive mouse DNA sequence is described which points to a functional role: All copies (approximately 50,000 per haploid genome) of this DNA sequence reside on genomic Alu I DNA fragments each associated with nuclear polypeptides that are not released from DNA by proteinase K, SDS and phenol extraction. By this quality the repetitive DNA sequence is classified as a member of the sub-set of DNA sequences involved in tight DNA-polypeptide complexes which have been previously shown to be components of the subnuclear structure termed 'nuclear matrix'. From these results it has to be concluded that the repetitive DNA sequence characterized in this report represents or comprises a signal for a large number of site specific attachment points of the mouse genome in the nuclear matrix.

Oesophageal carcinoma. Third-World modification of a First-World treatment programme

A 59-year-old man completed a course of cytotoxic treatment and palliative radiotherapy for stage III oesophageal carcinoma and then sought the aid of a traditional healer.

The role of U tube palliative treatment in high bile duct carcinoma

Twenty-one patients with cholangiocarcinoma at the confluence of the main right and left hepatic ducts were referred to our professorial surgical unit between 1968 and 1982. All were evaluated, treated, and documented prospectively with follow-up to mid 1986. No lesion was deemed resectable. The U tube palliative bypass developed during the course of the study was used in 14 patients, and its role in treating high bile duct carcinoma was evaluated. Histologic confirmation of the diagnosis was obtained in 71% of patients. Seven patients received additional treatment with radical radiotherapy. The 30-day overall hospital mortality rate was 19%. The 1- and 2-year survival rates were 57% and 33%, respectively. The quality of survival was usually good. The need for centralized referral and treatment of these difficult patients is stressed. The case against radical resection for this lesion is presented. It is concluded that radical resection is seldom possible, and therefore the U tube palliative procedure is advocated in most patients.

Carnitine plasma concentrations in 353 metabolically healthy children

Carnitine plasma concentrations were determined by an enzymatic radioisotopic method in 353 metabolically healthy children and in 41 adults. There was a positive correlation between total and free carnitine plasma concentrations and the age of the children. Both free and acylcarnitine concentrations were elevated on the 1st day of life, reflecting an increased rate of fatty acid oxidation. Carnitine plasma concentrations decreased after the 1st day and subsequently increased during the 1st year. From the 2nd year of life until adulthood, no further change was noted. Up to 17 years of age no differences were seen between male and female individuals. However, adult males had higher carnitine concentrations in plasma than adult females. Total carnitine concentrations were higher in 10- to 17-year-old females and lower in 10- to 17-year-old males compared with adults of the same sex, indicating a possible role for sex hormones in the regulation of carnitine plasma concentrations.

Particle density and protein composition of the peribacteroid membrane from soybean root nodules is affected by mutation in the microsymbiont Bradyrhizobium japonicum

Particle frequency of the peribacteroid membrane (PBM) from nodules of Glycine max (L.) Merr. cv. Maple Arrow infected with Bradyrhizobium japonicum 61-A-101 (wild-type strain) was determined by freeze-fracturing to be about 2200·μm(-2) in the protoplasmic fracture face and 700·μm(-2) in the exoplasmic fracture face. In membranes isolated from nodules infected with the mutant RH 31-Marburg of B. japonicum, the particle frequency was similar in both fracture faces with 1200-1300 particles·μm(-2). Analysis of particlesize distribution on peribacteroid membranes showed a loss, especially of particle sizes larger than 11 nm, in the mutant-infected nodules. Two-dimensional gel electrophoresis (isoelectric focussing and sodium dodecyl sulfate-polyacrylamide) showed 27 different polypeptides in the PBM from nodules infected with the wild-type strain, four of which were absent from the PBM of nodules infected with the mutant RH 31-Marburg, which also exhibited one extra small-molecular-weight polypeptide. At least 14 of the 27 polypeptides in the PBM from the wild-type-infected nodule were glycoproteins. In three of these glycoproteins, post-translational modifications were either lacking or different when the membrane was derived from mutant-infected nodules.

Cell cycle phase-specific cDNA libraries reflecting phase-specific gene expression of Ehrlich ascites cells growing in vivo

Asynchronous populations of Ehrlich ascites tumor cells grown in vivo were separated by centrifugal elutriation into fractions of G1-, S-, and G2/M-phase cells with less than 10% cross-contamination. Cytoplasmic mRNA from phase-synchronous cells was used to prepare cDNA which was ligated with bacteriophage lambda gt10 arms and amplified in Escherichia coli C600 hfl-. EcoRI digests of DNA isolated from the sublibraries (G1, S, G2/M) were submitted to Southern hybridizations with radiolabeled probes either (a) for genes whose phase-specific expression is clearly documented, thymidine kinase, dihydrofolate reductase, and thymidylate synthase, or (b) for genes whose change of expression during the cell cycle is likely, lamin C, beta-actin, alpha- and beta-tubulin, c-myc, c-fos, p53. The cDNA sequences for genes of group (a) were found to be significantly enriched in DNA of the S-phase library indicating that the cell cycle phase-specific patterns of the respective mRNA levels are conserved in the sublibraries. Sequences belonging to group (b) were also found to be enriched in DNA isolated from the sublibraries: c-fos in G1 phase, lamin C, beta-actin, tubulins, c-myc in S phase, and p53 in G1/S phase. The unexpected prevalence of c-myc and alpha-tubulin in the S-phase library is supported by Northern analysis of RNA from phase-synchronous cells. Non-phase-specific, randomly chosen sequences hybridized equally strong with DNA isolated from the different sublibraries. No significant changes of the patterns of hybridization signals were observed with DNA from different amplifications of the sublibraries when analyzed with the same DNA probe indicating that the cDNA complexities are well conserved during amplifications. Consequently, the sublibraries are useful to obtain information about the cell cycle phase-specific expression of mRNAs for other genes of interest. Since the sublibraries reflect mRNA levels of the cells growing in vivo they supply data on the physiological in vivo pattern of gene expression undisturbed by potentially unphysiological in vitro conditions.

Sub-set characteristics of DNA sequences involved in tight DNA/polypeptide complexes and their homology to nuclear matrix DNA

Polypeptides co-isolating with DNA induce the binding of a fraction of native DNA fragments to nitrocellulose filters. Southern analysis reveals a high intensity of self-hybridization of the DNA sequences retained on nitrocellulose filters. Consistently, the DNA fraction passing the filters shows only weak hybridization when probed with DNA retained on filters. This indicates that the DNA/polypeptide complexes reside on a non-random sub-set of DNA sequences. Moreover, a high degree of homology was found between residual nuclear matrix DNA sequences and the DNA sequences retained on nitrocellulose filters. This indicates that the DNA sequences associated with tightly bound polypeptides originate from sites where the genome is salt-stably anchored in the nuclear matrix.

Radiolabelling of DNA/polypeptide complexes in isolated bulk DNA and in residual nuclear matrix DNA by nick-translation

Conditions are described that allow 32P-radiolabelling and detection of tight complexes between DNA and polypeptides by nick-translation. Prolonged nick-translation of purified bulk DNA results in radiolabelled complexes migrating on SDS-polyacrylamide gels with apparent molecular weights of 68 kd and 54 kd respectively. Residual nuclear matrix DNA which is not accessible to DNase I on the nuclear level becomes accessible to radiolabelling by nick-translation on the nuclear matrix level. In this case the in situ radiolabelled complexes migrate on SDS-polyacrylamide gels with apparent molecular weights of 68 kd and 100 kd. The DNA/polypeptide complexes are stable during treatments with SDS, beta-mercapto ethanol and alkali which points to covalent bonds between the polypeptides and DNA strands.

Disintegration of nucleoskeletal elements by metrizamide/2 M salt isopyknic centrifugation

Supramolecular structures that remain bound to chromosomal DNA under high salt conditions are believed to anchor DNA in the interphase nuclear skeleton. In order to identify these anchorage structures, the non-DNA materials that remain firmly bound to chromosomal DNA under conditions that disintegrate the high salt-stable architecture of nuclei were investigated. Nuclei of Ehrlich ascites cells were histone-depleted by treatment with 2 M salt. The residual halo structures were gently sheared and subjected to metrizamide isopyknic centrifugation in the presence of 2 M salt. By this combined treatment the high salt stable nuclear skeleton becomes disintegrated and three main fractions are resolved. A light fraction comprises the DNA which appears to be essentially depleted of other nuclear components. The only non-DNA material that could be identified in the DNA band is a fraction of (nascent) RNP. No other materials which could reflect nucleoskeletal elements (e.g. lamina proteins) were found together with DNA. A peak of intermediate density comprises RNA/RNP dissociated from DNA. The heavy fraction contains the proteins that become dissociated from DNA by high-salt and/or centrifugal forces, e.g. histones and the major nuclear lamina proteins. The results indicate that nascent RNP is more tightly bound to chromosomal DNA than other components that may be involved in nuclear skeletons. This suggest that transcription complexes represent at least one type of anchorage structure of DNA, which is consistent with results indicating that nascent RNA and actively transcribed DNA sequences are preferentially retained in high-salt-treated nuclei.

Thiazide-induced hyponatremia: an unusual neurologic course

We have presented a case of thiazide-induced hyponatremia that followed an unusual course after the patient, suffering from extreme lethargy, was admitted with a serum sodium concentration of 104 mEq/L. Although the electrolyte imbalance was essentially corrected within 20 hours and there was clinical improvement, three days later the patient suddenly lost consciousness. She was comatose for more than a month, apparently from extrapontine myelinolysis. After a dramatic improvement, the patient was discharged with almost no neurologic deficit.

Inhibition of Lewis lung tumor growth and metastasis by Ehrlich ascites tumor growing in the same host

A double tumor model (3LL and EAT) was established in C57BL/6 mice. The primary 3LL tumor was growth-inhibited by EAT inoculated into the same host. Growth inhibition of the 3LL primary tumor depended on the number of EAT cells injected. Inhibition of the growth of the primary 3LL tumor was also observed after injection of the optimal number (10(7)) of EAT cells 24 h to 7 days before or after inoculation of 3LL cells. In contrast, metastasis of the 3LL tumor was only inhibited after simultaneous inoculation of 3LL and ETA cells. Moreover, EAT cells inhibited the growth of preformed 3LL-derived metastases after resection of the primary 3LL tumor. Although the EAT-induced stimulation of a host defense system is not excluded, the results are consisted with the continued release of growth inhibition factors from EAT cells acting on 3LL cells in the primary tumor and in lung metastases.

Amino-acid-transfer reactions in isolated nuclei of Ehrlich ascites tumor cells

Nuclear enzymatic activities incorporating amino acids into acid-insoluble material were investigated with respect to their differentiation from protein biosynthesis, reaction optima, requisites and localization. The product of the reaction was analyzed with respect to its localization and nature. The nuclear activities are not inhibited by a number of inhibitors for protein biosynthesis. The reaction optima found are similar to those of other residual nuclear syntheses including the stringent dependence on ATP. All naturally occurring amino acids are utilized with different efficiencies. Their incorporation is neither cooperative nor competitive which points to individual incorporation mechanisms. Aminoacylation of tRNA may be involved because the incorporation is RNase-sensitive and aminoacylation of tRNA can be shown under the reaction conditions. The enzymatic activities are exclusively nuclear. Significant activity with unchanged characteristics is released by sonication. 70% of the radiolabel incorporated is exported across the nuclear envelope during the incubation. The residual 30% of the radiolabel is distributed without enrichment in any nuclear subfraction. The products are exclusively of polypeptide nature. Since distinct nuclear proteins (e.g. histones) which are definitely preformed in the cytoplasm by protein biosynthesis become radiolabelled by the incorporation of radiolabelled amino acids, it is evident that the incorporation takes place at preformed polypeptides. This is unequivocally proven by the incorporation of radiolabelled amino acids into exogenous proteins by means of the solubilized nuclear activities. The results indicate that the nuclear activity under investigation reflects a nuclear modification system for polypeptides which may be of similar importance as other post-translational modification systems.

Purification of a phospholipase B inhibitor from Saccharomyces cerevisiae

The phospholipase B activity of plasma membrane vesicles from Saccharomyces cerevisiae is inhibited by the 100 000 X g supernatant of mechanically disrupted yeast cells. A 1850-fold purification of the inhibitor activity was achieved by gel filtration, ion exchange chromatography with DEAE-cellulose and hydrophobic interaction chromatography with Octyl-Sepharose. SDS-polyacrylamide gel electrophoresis of the purified inhibitor revealed two main bands with an apparent Mr of 60 000 and 26 500. The phospholipase B activity was strongly reduced but not completely blocked by this preparation, while the lysophospholipase and transacylase reactions, which are catalyzed by the same membrane-bound enzymes (Witt, W. et al. (1984) Biochim. Biophys. Acta 795, 108-116), were not affected.

Screening of isolated DNA for sequences released from anchorage sites in nuclear matrix

Isolated chromosomal DNA is associated with polypeptides that are not released from DNA by several methods designed to purify DNA, e.g. treatment with sodium dodecyl sulphate. DNA fragments associated with these very tight DNA/protein complexes show high affinity to nitrocellulose filters in the presence of salt concentrations of 500 mM or greater. Consequently, a fraction of AluI-fragmented native DNA comprising the complexes and 0.2 to 0.3 micron of vicinal DNA can be isolated by one filtration step. This fraction of DNA shows characteristics of residual DNA sequences retained in nuclei after extraction with nucleases and high salt (nuclear matrix). The DNA fragments retained on filters are highly enriched in replicative DNA; and their degree of hybridization with poly(A)+ RNA points to enrichment in actively transcribed sequences. The results support previous work indicating that the very tight DNA/polypeptide complexes co-isolating with DNA under conditions that release other peptide materials from DNA may be anchorage sites of DNA in the nuclear matrix. Moreover, the method described here allows isolation of replicating and actively transcribed DNA sequences directly from isolated total genomic DNA by skipping artefact-prone isolations of the nuclear matrix.

Acute hemolytic anemia caused by severe hypophosphatemia in diabetic ketoacidosis

Hypophosphatemia in diabetic ketoacidosis is well recognized, but is believed to be usually of moderate severity. We describe 2 patients in whom acute hemolytic anemia secondary to severe (0.19-0.35 mmol/l) hypophosphatemia has developed 1-2 days following treatment for diabetic ketoacidosis. Our experience indicates that severe hypophosphatemia requiring phosphate supplementation does occur in diabetic patients, and calls for increased awareness for the clinical and laboratory manifestations of this complication of diabetic ketoacidosis.

Isolation of poly(A)+ RNA by paper affinity chromatography

Poly(A)+ RNA was isolated from in vitro short-term-labeled total cytoplasmic RNA of Ehrlich ascites tumor cells by oligo(dT) cellulose chromatography. This poly(A)+ RNA fraction was compared with a poly(A)+ RNA fraction isolated by a new procedure which involves specific binding of poly(A)+ RNA to messenger affinity paper (mAP) and its release in hot (70 degrees C) water. In typical experiments 10-11 micrograms (2.3%) of poly(A)+ RNA can be retained from 500 micrograms of total cytoplasmic RNA per cm2 of mAP in a quick one-step procedure. The poly(A)+ RNA preparations isolated by the two methods proved to be almost identical with respect to their fraction in total cytoplasmic RNA, specific radioactivities, sucrose gradient profiles, and translation assays. Since the isolation of poly(A)+ RNA by mAP is much less time consuming than that by oligo(dT) column chromatography and since the poly(A)+ RNA can be recovered from mAP in small volumes, which avoids further loss during precipitations, it can be advantageously used for preparative isolation of poly(A)+ RNA.

Lysis of bacterioids in the vicinity of the host cell nucleus in an ineffective (fix(-)) root nodule of soybean (Glycine max)

In nodules of Glycine max cv. Mandarin infected with a nod (+)fix(-) mutant of Rhizobium japonicum (RH 31-Marburg), lysis of bacteroids was observed 20 d after infection, but occurred in the region around the host cell nucleus, where lytic compartments were formed. Bacteroids, and peribacteroid membranes in other parts of the host cell remained stable until senescence (40d after infection). With two other nod(+) fix(-) mutants of R. japonicum either stable bacteroids and peribacteroid membranes were observed throughout the cell (strain 61-A-165) or a rapid degeneration of bacteroids without an apparent lysis (strain USDA 24) occurred. The size distribution of RH 31-Marburg-infected nodules exhibited only two maxima compared with four in wild-type nodules and nodule leghaemoglobin content was found to be reduced to about one half that of the wild type. The RH 31-Marburg-nodule type is discussed in relation to the stability of the bacteroids and the peribacteroid membrane system in soybean.

Grand-mal as the major presenting symptom of infectious mononucleosis

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Antibodies to the most tightly bound proteins in eukaryotic DNA. Formation of immuno-complexes with 'nuclear matrix' components

Chromosomal DNA is associated with polypeptides covalently bound to internal DNA ends. Since these polypeptides can only be released from chromosomal DNA by enzymes or other agents hydrolysing phosphodiester bonds they were termed 'the most tightly bound' (MTB) polypeptides in DNA. Antibodies developed against the MTB polypeptides are shown to form immunocomplexes with major 'nuclear matrix' polypeptides as well as with polypeptides which are still associated with 'nuclear matrix' DNA isolated by means of SDS/proteinase K and phenol. Immuno-complex formation is revealed by immunoblotting and by indirect immunofluorescence. Thus, since MTB polypeptides, major 'nuclear matrix' polypeptides and 'nuclear matrix' DNA-associated polypeptides share common antigenic sites they can be considered to be identical or at least closely related. This suggests that a fraction of distinct 'nuclear matrix' polypeptides is either transiently or permanently linked to DNA by covalent bonds. Consistently, isolated eukaryotic 'bulk' DNA is inevitably associated with residual 'nuclear matrix' polypeptides.

Effects of dietary sucrose on factors influencing cholesterol gall stone formation

Twelve subjects with radiolucent gall stones and bile supersaturated with cholesterol were studied after six weeks each on diets which contained 112 g and 16 g respectively of refined (fibre depleted) sucrose but which allowed free access to other foods. Energy intake was 24.5% higher on the high sugar diet and body weight ended 1.4 kg higher than on the low sugar diet. Biliary secretion rates of cholesterol, phospholipid and bile acid, measured by a perfusion technique, were similar on the two diets, as were the bile acid pool sizes measured by isotope dilution. Cholesterol saturation index of fasting 'gall bladder' bile was 1.30 +/- 0.11 and 1.37 +/- 0.14 on high and low sugar respectively (NS). Plasma triglycerides were 36% higher and plasma high density lipoprotein cholesterol concentrations were 9% lower on the high sugar diet. These findings indicate that over a six week period refined sugar in normally consumed amounts does not adversely affect the lipid composition of bile.

Highly sensitive sites for guanine-O6 ethylation in rat brain DNA exposed to N-ethyl-N-nitrosourea in vivo

Brain chromosomal DNA isolated from fetal BDIX-rats 1 h after i.v. administration of the ethylating N-nitroso carcinogen N-ethyl-N-nitrosourea (75 micrograms/g body weight), statistically contained one molecule of O6-ethyl-2'-deoxyguanosine (O6-EtdGuo) per 81 micron of DNA, as determined in enzymatic DNA hydrolysates by competitive radio-immunoassay using a high-affinity anti-(O6-EtdGuo) monoclonal antibody (ER-6). After fragmentation of the DNA by the restriction enzyme AluI (average fragment length, Lav = 0.28 micron = 970 bp; length range, Lr = 1.87-0.02 micron = 6540 - 60 bp), a small (approximately 2%) fraction of DNA enriched in specific polypeptides tightly associated with DNA was separated from the bulk DNA by a glass fiber binding technique. As analyzed by immune electron microscopy, approximately 1% of the DNA molecules in this fraction contained clusters of 2-10 (O6-EtdGuo)-antibody binding sites (ABS). On the cluster-bearing fragments (Lav, 0.85 micron +/- 0.50 micron S.D.; corresponding to 2970 +/- 1760 bp) the average ABS-ABS interspace distance was 110 nm (= 390 bp; range approximately 9-600 nm), indicating a highly non-random distribution of O6-EtdGuo in target cell DNA.

DNA polymerases in isolated 'nuclear matrix' of Ehrlich ascites cells

Isolated nuclei from Ehrlich ascites tumor cells continue a replicative-like in vitro DNA synthesis. Polymerase alpha is the major dNTP polymerizing enzyme in nuclei. Following complete achromatinization dNTP polymerizing activities are still associated with the residual structure termed 'nuclear matrix'. In contrast to DNA synthesis in native nuclei, 'nuclear matrix' DNA synthesis is mainly due to polymerase beta-like activity.

Hodgkin's disease in children. A ten-year experience in South Africa

Twenty-seven children with Hodgkin's disease were treated with MVOPP (mustine, Velban [vinblastine], Oncovin [vincristine], procarbazine, prednisone) combination chemotherapy. All 11 children with Stage I or Stage II disease achieved complete remission and no relapses have occurred between 34 and 179 months of continuous follow-up. Of the 16 children with Stage III or Stage IV disease, two with partial remission and three nonresponding patients died with a median survival of 18 months. The remaining 11 (68%) achieved complete remission. Of these, 6 (55%) have relapsed with a median remission duration of 36 months; five have been retreated with MVOPP, and one with total nodal irradiation, and all achieved second complete remission. Three of the children have died of Hodgkin's disease, with a median survival of 55 months; one child died of acute myeloblastic leukemia while in remission; and one child remains disease-free off all therapy at 165 months; the sixth child treated with total nodal irradiation is disease-free at 166 months. The initial complete remission has been sustained in all 11 children with Stage I or Stage II Hodgkin's disease, suggesting that combination chemotherapy is an alternative to radiotherapy as the initial form of treatment in this group of individuals.

Fragmentation of 'nuclear matrix' on a mica target

Chromatin depleted nuclei ('nuclear matrix') of Ehrlich ascites cells were characterized and fragmented by glycerol shot technique (particle fragmentation). The preparations reveal that 'nuclear matrix' is entirely composed of granules and fibres. Prominent size classes of granules are 10 to 20 nm and 25 to 40 nm, respectively. Most of the granules remain attached to fibres during the fragmentation process. The diameter of the fibres corresponds with double-stranded DNA visualized under identical conditions. The RNP-like nature of the particles is shown by their proteinase K/RNase sensitivity. Since the 'nuclear matrix' architecture becomes instable in high salt buffer after pretreatment with RNase which changes the RNP-particle-like material it must be inferred that the RNP/DNA interaction is a prerequisite for the high salt stability of the 'nuclear matrix' complex.