Replication-dependent and independent regulation of HMG expression during the cell cycle and conjugation in Tetrahymena.

Two abundant high-mobility-group (HMG)-like proteins, HMG B and HMG C, exist in the ciliated protozoan, Tetrahymena thermophila. Of these, HMG C is specific to transcriptionally active macronuclei, while HMG B is found in macronuclei and in transcriptionally inactive micronuclei [1]. Using Northern and in situ analyses, we show that the genes encoding HMG B and HMG C are not expressed uniformly throughout the vegetative cycle or during the sexual process, conjugation. Elevated expression of both genes is observed during macronuclear S phase of the vegetative cycle and during endoreplication of developing new macronuclei in later stages of conjugation. Interruption of any of these macronuclear DNA replications by aphidicolin leads to a rapid drop in the message levels of HMG B and HMG C. These results resemble what is typically observed for replication-dependent nucleosomal histones and differ from the apparent lack of cell cycle regulation observed for HMG genes in vertebrates. A specific-induction of HMG B mRNA is also observed early in conjugation and during this interval, inhibition of micronuclear DNA synthesis by aphidicolin does not affect the message level of HMG B. Thus, during conjugation, expression of HMG B shows both replication-dependent and independent regulation. Results similar to these with HMG B are obtained with histone H4II gene, a gene which is also expressed during micro- and macronuclear S phases during the vegetative cycle. These results demonstrate surprising complexity in the expression of HMG genes in Tetrahymena and lend support to the hypothesis that cell cycle regulation plays an important role in directing HMG-like proteins to the appropriate nucleus [2]. Interestingly, expression of neither HMG gene is perfectly synchronized with that of histone H4II gene during the developmental program suggesting that important differences exist between vegetatively growing (cell cycle control) and conjugating (developmental control) cells.


Prediction of the structure of the Y+.R-.R(+)-type DNA triple helix by molecular modelling.

Molecular mechanics has been used to predict the structure of the Y+.R-.R(+)-type DNA triple helix, in which a second polypurine strand binds antiparallel to the homopurine strand of a homopurine/homopyrimidine stretch of duplex DNA. From calculations on the sequence d(C)10.d(G)10.d(G)10, two likely structures emerge. One has the glycosidic torsions of the third strand bases in the anti-conformation and Hoogsteen hydrogen-bonds to the purine strand of the duplex, the other has the third strand purines in the syn orientation and uses a reverse-Hoogsteen hydrogen-bonding pattern. Despite the large structural differences between these two types of triplex, calculations performed in vacuo with a distance-dependent dielectric constant to mimic the shielding effect of solvent show them to be energetically very similar, with the latter (syn) slightly preferred. However, if explicit solvent molecules are included in the calculation, the anti conformation is found to be much preferred. This difference in the results seems to stem from an underestimation of short-range electrostatic interactions in the in vacuo simulations. When TAA or TAT base triples are substituted for the sixth CGG triple in the sequence, it is found that, for the solvated model, the third strand base of the TAA triple prefers the syn orientation while that in the TAT triple retains a preference, though reduced, for the anti conformation.


NMR observation of individual molecules of hydration water bound to DNA duplexes: direct evidence for a spine of hydration water present in aqueous solution.

The residence times of individual hydration water molecules in the major and minor grooves of DNA were measured by nuclear magnetic resonance (NMR) spectroscopy in aqueous solutions of d-(CGCGAATTCGCG)2 and d-(AAAAATTTTT)2. The experimental observations were nuclear Overhauser effects (NOE) between water protons and the protons of the DNA. The positive sign of NOEs with the thymine methyl groups shows that the residence times of the hydration water molecules near these protons in the major groove of the DNA must be shorter than about 500 ps, which coincides with the behavior of surface hydration water in peptides and proteins. Negative NOEs were observed with the hydrogen atoms in position 2 of adenine in both duplexes studied. This indicates that a 'spine of hydration' in the minor groove, as observed by X-ray diffraction in DNA crystals, is present also in solution, with residence times significantly longer than 1 ns. Such residence times are reminiscent of 'interior' hydration water molecules in globular proteins, which are an integral part of the molecular architecture both in solution and in crystals.


Solid-phase synthesis of branched oligoribonucleotides related to messenger RNA splicing intermediates.

The chemical synthesis of oligoribonucleotides containing vicinal (2'-5')- and (3'-5')-phosphodiester linkages is described. The solid-phase method, based on silyl-phosphoramidite chemistry, was applied to the synthesis of a series of branched RNA [(Xp)nA2' (pN)n3'(pN)n] related to the splicing intermediates derived from Saccharomyces cerevisiae rp51a pre-messenger RNA. The branched oligonucleotides have been thoroughly characterized by nucleoside and branched nucleotide composition analysis. Branched oligoribonucleotides will be useful in the study of messenger RNA splicing and in determining the biological role of RNA 'lariats' and 'forks' in vivo.


Identity elements for N2-dimethylation of guanosine-26 in yeast tRNAs.

N2,N2-dimethylguanosine (m2(2)G) is a characteristic nucleoside that is found in the bend between the dihydro-uridine (D) stem and the anticodon (AC) stem in over 80% of the eukaryotic tRNA species having guanosine at position 26 (G26). However, since a few eukaryotic tRNAs have an unmodified G in that position, G26 is a necessary but not a sufficient condition for dimethylation. In yeast tRNA(Asp) G26 is unmodified. We have successively changed the near surroundings of G26 in this tRNA until G26 became modified to m2(2)G by a tRNA(m2(2)G26)methyltransferase in Xenopus laevis oocytes. In this way we have identified the two D-stem basepairs C11-G24, G10-C25 immediately preceding G26 as major identity elements for the dimethylating enzyme modifying G26. Furthermore, increasing the extra loop in tRNA(Asp) from four to the more usual five bases influenced the global structure of the tRNA such that the m2(2)G26 formation was drastically decreased even if the near region of G26 had the two consensus basepairs. We conclude that not only are the two consensus base pairs in the D-stem a prerequisite for G26 modification, but also is any part of the tRNA molecule that influence the 3D-structure important for the recognition between nuclear coded tRNAs and the tRNA(m2(2)G26)methyltransferase.


A conserved DNA structural control element modulates transcription of a mammalian gene.

The mammalian dihydrofolate reductase (DHFR) gene promoters contain several conserved sequence elements which bind protein, and yet there are other conserved DNA sequences that do not footprint. We report here that mutation of one of these conserved non-footprinting regions increases transcription from this promoter both in vitro and in vivo. We show that this conserved region is flanked by sites hypersensitive to cleavage by methidiumpropyl-EDTA-Fe(II). Furthermore, multimers of a double-stranded oligonucleotide comprised of this region display faster migration through polyacrylamide than control DNA. The difference in mobility is not the result of bending, nor does the primary sequence contain features that would predict altered mobility. We propose that this 'Structural Control Element' is rigid and down-regulates transcription by inhibiting interactions between proteins binding adjacent to this region.


Introns of the chicken ovalbumin gene promote nucleosome alignment in vitro.

A defined in vitro chromatin assembly system was used to examine the nucleosome alignment induced by histone H5 throughout a 12 kilobase pair chicken genomic DNA fragment containing the ovalbumin gene. In contrast with total fragmented chicken DNA and several anonymous cloned fragments, much of the gene permitted histone H5 to space nucleosomes at physiological intervals in an extended array. Nucleosomes at the 3'-end of the gene and on approximately 4 kilobase pairs of 5'-flanking ovalbumin sequence did not become aligned to appreciable extents. Analysis of cloned 2-3 kilobase pair subfragments suggested that a strong nucleosome alignment signal, specifying a 196 +/- 5 base pair repeat exists in intron E. A second discrete region of the gene, which mapped approximately to intron A, exhibited nucleosome alignment with a spacing periodicity of about 200 base pairs. The ovalbumin cDNA did not permit nucleosome alignment. These findings suggest that some of the introns contain signals that direct nucleosome alignment over the ovalbumin gene in a way conducive to its regulation.


Differential utilization of poly (A) signals between DHFR alleles in CHL cells.

The Chinese hamster cell line, DC-3F, is heterozygous at the DHFR locus, and each allele can be distinguished on the basis of a unique DNA restriction pattern, protein isoelectric profile and in the abundancy of the DHFR mRNAs it expresses. Although each allele produces four transcripts, 1000, 1650 and 2150 nucleotides [corrected] in length, the relative distribution of these RNAs differs for each; the 2150 nt mRNA represents the major (60%) species generated from one allele, while the 1000 nt mRNA is the major species generated from the other. The allele that predominantly expresses the 2150 nt transcript is preferentially overexpressed when DC-3F cells are subjected to selection in methotrexate. We have analyzed the 3' ends of both DHFR alleles and have found that the three major mRNAs arise by readthrough of multiple polyadenylation signals. A four base deletion in one allele changes the consensus polyadenylation signal AAUAAA to AAUAAU, resulting in the utilization of a cryptic polyadenylation signal lying 21 bp upstream. Surprisingly, this mutation in the third polyadenylation signal appears to affect not only the utilization of this signal, but also the efficiency with which the first signal, located 1171 bp upstream from the third site, is utilized.


Cloning and characterization of rad21 an essential gene of Schizosaccharomyces pombe involved in DNA double-strand-break repair.

Analysis of the Schizosaccharomyces pombe chromosomes by pulsed field gel electrophoresis showed that the fission yeast has a very efficient DNA double-strand-break (dsb) repair system, which properly restores the three chromosomes after they are degraded by gamma-irradiation. The radiation-sensitive mutant rad21-45 is deficient in this repair pathway but is capable of cell-cycle arrest in G2 following DNA damage. We cloned the rad21 gene by complementing the radiation sensitivity of the rad21-45 mutant. The plasmid-borne gene completely reestablished the DNA dsb repair pathway. The rad21 gene was localized to chromosome III by hybridization. The transcript is 2.5 kb long and expressed at a moderate level. The 1884-bp open reading frame encodes a 628 amino acid, very acidic peptide with a calculated molecular mass of 67,854 D. The rad21 gene shows no significant homology to other known nucleotide or peptide sequences. The inability of the mutant to perform efficient DNA repair is caused by a single base substitution, which changes wild-type isoleucine67 into threonine in the mutant. Deletion of the genomic rad21 gene showed that it is essential for mitotic growth of S.pombe.


Mutations at the guanosine-binding site of the Tetrahymena ribozyme also affect site-specific hydrolysis.

Self-splicing group I introns use guanosine as a nucleophile to cleave the 5' splice site. The guanosine-binding site has been localized to the G264-C311 base pair of the Tetrahymena intron on the basis of analysis of mutations that change the specificity of the nucleophile from G (guanosine) to 2AP (2-aminopurine ribonucleoside) (F. Michel et al. (1989) Nature 342, 391-395). We studied the effect of these mutations (G-U, A-C and A-U replacing G264-C311) in the L-21 ScaI version of the Tetrahymena ribozyme. In this enzymatic system (kcat/Km)G monitors the cleavage step. This kinetic parameter decreased by at least 5 x 10(3) when the G264-C311 base pair was mutated to an A-U pair, while (kcat/Km)2AP increased at least 40-fold. This amounted to an overall switch in specificity of at least 2 x 10(5). The nucleophile specificity (G > 2AP for the G-C and G-U pairs, 2AP > G for the A-U and A-C pairs) was consistent with the proposed hydrogen bond between the nucleotide at position 264 and N1 of the nucleophile. Unexpectedly, the A-U and A-C mutants showed a decrease of an order of magnitude in the rate of ribozyme-catalyzed hydrolysis of RNA, in which H2O or OH- replaces G as the nucleophile, whereas the G-U mutant showed a decrease of only 2-fold. The low hydrolysis rates were not restored by raising the Mg2+ concentration or lowering the temperature. In addition, the mutant ribozymes exhibited a pattern of cleavage by Fe(II)-EDTA indistinguishable from that of the wild type, and the [Mg2+]1/2 for folding of the A-U mutant ribozyme was the same as that of the wild type. Therefore the guanosine-binding site mutations do not appear to have a major effect on RNA folding or stability. Because changing G264 affects the hydrolysis reaction without perturbing the global folding of the RNA, we conclude that the catalytic role of this conserved nucleotide is not limited to guanosine binding.


Euplotes crassus has genes encoding telomere-binding proteins and telomere-binding protein homologs.

We have identified two 1.6 kb macronuclear DNA molecules from Euplotes crassus that hybridize to the alpha subunit of the Oxytricha telomere protein. We have shown that one of these molecules encodes the 51 kDa Euplotes telomere protein while the other appears to encode a homolog of the telomere protein. Although this homolog clearly differs in sequence from the Euplotes telomere protein, the two proteins share extensive amino acid sequence identity with each other and with the alpha subunit of the Oxytricha telomere protein. In all three proteins 35-36% of the amino acids are identical, while 54-56% are similar. The most extended regions of sequence conservation map within the N-terminal section; this section has been shown to comprise the DNA-binding domain in the Euplotes telomere protein. Our findings suggest that some of the conserved amino acids may be involved in DNA recognition and binding. The gene encoding the telomere protein homolog contains two introns; one of these introns is only 24 bp in length. This is the smallest mRNA intron reported to date.


A single-stranded DNA binding protein from mouse tumor cells specifically recognizes the C-rich strand of the (AGG:CCT)n repeats that can alter DNA conformation.

A protein that binds to a synthetic oligonucleotide of (CCT)12 has been purified from Ehrlich ascites tumor cells by a (CCT)12 affinity chromatography. The protein (p70) has an apparent molecular mass of 70 kDa, as assayed by Southwestern analysis. A competition experiment revealed that p70 binds to (CCT)12, (CCCT)8 and (CCTCCCT)6, but not to (CTT)12, (CT)16 and (CCTGCCT)6, suggesting that p70 has a sequence-specificity. The complementary (AGG)12 and the double stranded DNA did not show the binding. It is also confirmed by S1 nuclease analysis that the (AGG:CCT)12 duplex takes a single-stranded conformation in the absence of the protein. This raises a possibility that the duplex forms two single-stranded loops in chromosomes, the C-rich strand being bound to p70. Structural analysis of the resulting (AGG)12 strand by non-denaturing polyacrylamide gel electrophoresis demonstrated the presence of slower and faster migrated conformers in a neutral pH buffer containing 50 mM NaCl at 5 degrees C. The ratio was dependent on the DNA concentration. Both conformers disappeared in the absence of NaCl. This suggests that (AGG)12 can form intra- and inter-molecular complexes by non-Watson-Crick, guanine:guanine base-pairing. The possible biological function of the (AGG:CCT)n duplex and the p70 is discussed.


Crystal and molecular structure of the alternating dodecamer d(GCGTACGTACGC) in the A-DNA form: comparison with the isomorphous non-alternating dodecamer d(CCGTACGTACGG).

The crystal structure of the alternating dodecamer d(GCGTACGTACGC) (5'-GC) has been determined to a resolution of 2.55A using oscillation film data. The crystals belong to space group P6(1) 22, a = b = 46.2A, c = 71.5A with one strand in the asymmetric unit, and are isomorphous with a previously described non-alternating dodecamer, d(CCGTACGTACGG) (5'-CC). Refinement by X-PLOR/NUCLSQ gave a final R factor of 14.2% for 1089 observations. The molecule adopts the A-DNA form. The interchange of the terminal base pairs in the two dodecamers results in differences in the intermolecular contacts and may account for the differences in the bending. This dodecamer shows an axial deflection of 30 degrees, in the direction of the major groove compared to 20 degrees in 5'-CC and may be a consequence of additional contacts generated in 5'-GC by the interchange of end base pairs. The high helical axis deflection appreciably influences the local helical parameters. The molecule exhibits relatively high inclination angles, and has a narrow major groove. The helical parameters when described relative to the dyad-related hexamer halves of the molecule give more reasonable values. The crystal packing, local helical parameters, torsion angles, and hydration are described and also compared with the non-alternating 5'-CC dodecamer.


Small sequence insertions within the branch point region dictate alternative sites of lariat formation in a yeast intron.

The problem of intron recognition in S. cerevisiae appears to be in part solved by the strong conservation of intron encoded splicing signals, in particular the 5' GUAUGU and the branch point UACUAAC which interact via base pairing with the RNA components of U1 and U2 snRNPs respectively. Nevertheless, the mere presence of such signals is insufficient for splicing to occur. In the S. cerevisiae ACT1 intron, a silent UACUAAC-like sequence (UACUAAG) is located 7 nucleotides upstream of the canonical branch point signal. In order to investigate whether other factors, in addition to the U2-UACUAAC base-pair interactions, affect branch point selection in yeast, we created a cis-competition assay by converting the UACUAAG to a strong branch point signal (UACUAAC). If simply having a canonical UACUAAC sequence were sufficient for lariat formation, a 1:1 ratio in usage of the two signals should have been observed. In this double branch point intron, however, the downstream UACUAAC is utilized preferentially (4:1). Results obtained from the analyses of numerous sequence variants flanking the two UACUAAC sequences, demonstrate that non-conserved sequences in the branch point region are able to define lariat formation. Consequently, we conclude that U2 base-pairing is not the only requirement determining branch point selection in yeast, and local structure in the vicinity of the branch point could play a critical role in its recognition.


Digital chemiluminescence imaging of DNA sequencing blots using a charge-coupled device camera.

Digital chemiluminescence imaging with a cryogenically cooled charge-coupled device (CCD) camera is used to visualize DNA sequencing fragments covalently bound to a blotting membrane. The detection is based on DNA hybridization with an alkaline phosphatase(AP) labeled oligodeoxyribonucleotide probe and AP triggered chemiluminescence of the substrate 3-(2'-spiro-adamantane)-4-methoxy-4-(3"-phosphoryloxy)phenyl- 1,2-dioxetane (AMPPD). The detection using a direct AP-oligonucleotide conjugate is compared to the secondary detection of biotinylated oligonucleotides with respect to their sensitivity and nonspecific binding to the nylon membrane by quantitative imaging. Using the direct oligonucleotide-AP conjugate as a hybridization probe, sub-attomol (0.5 pg of 2.7 kb pUC plasmid DNA) quantities of membrane bound DNA are detectable with 30 min CCD exposures. Detection using the biotinylated probe in combination with streptavidin-AP was found to be background limited by nonspecific binding of streptavidin-AP and the oligo(biotin-11-dUTP) label in equal proportions. In contrast, the nonspecific background of AP-labeled oligonucleotide is indistinguishable from that seen with 5'-32P-label, in that respect making AP an ideal enzymatic label. The effect of hybridization time, probe concentration, and presence of luminescence enhancers on the detection of plasmid DNA were investigated.


Effect of glycerol on the separation of nucleosomes and bent DNA in low ionic strength polyacrylamide gel electrophoresis.

We report that glycerol changes the separation characteristics of polyacrylamide nucleoprotein gels in which it is included as a stabilizing agent. Polyacrylamide gel electrophoresis fractionates DNA and nucleosomes according to net negative charge, mass and conformation. With glycerol included, fractionation seems to be largely based on particle mass and charge. The conformation factor in separation is progressively lost with increasing glycerol concentrations. Nucleosome positions on the same DNA fragment are no longer resolved, while the difference in electrophoretic mobility between core particles and nucleosomes carrying longer DNA becomes smaller and is eventually lost. The retardation of bent DNA is also much reduced. Using the differences in separation characteristics between glycerol-containing and regular nucleoprotein gels could be a new means to obtain information on macromolecules in solution.


Periodic binding of individual core histones to DNA: inadvertent purification of the core histone H2B as a putative enhancer-binding factor.

By using a DNase I footprinting assay, we have purified a factor by DNA affinity chromatography that binds to the minimal enhancer region of the Drosophila knirps gene and subsequently identified the protein as the core histone H2B. This inadvertent purification of a core histone as a putative sequence-specific DNA binding protein was due to a previously unknown property of H2B to interact with DNA in a periodic manner. Moreover, we found that each of the individual core histones, but not histone H1 or high mobility group protein 1, bound to the knirps enhancer to give a repetitive DNase I footprint pattern with a periodicity of about 10 base pairs, which is approximately one turn of the DNA helix. In addition, preparations containing the core histones H2A-H2B or H3-H4 yielded identical periodic DNase I footprint patterns on several different promoter and enhancer regions. These findings suggest that there are periodic, homotypic interactions between DNA-bound core histones that result from an alteration of the overall DNA structure such as the curvature rather than a specific sequence. We have also shown that histones H2A-H2B can repress initiation of transcription by RNA polymerase II. The phenomena described here may reflect histone-DNA interactions in non-nucleosomal stretches of chromatin and could be involved in some aspects of either rotational or translational positioning of nucleosomes. Furthermore, these findings indicate that a repeated 10 bp DNase I ladder, which has previously been considered to be a property of an intact nucleosome, can also be generated with subnucleosomal components. It will thus be necessary to reevaluate the criteria applied to the analysis of nucleosomes both in vivo and in vitro.


Plateau distributions of DNA fragment lengths produced by extended light exposure of extranuclear photosensitizers in human cells.

We have exploited properties of photosensitizers to study an aspect of the packing of chromatin in the cell nucleus. The fluorescent photosensitizers mesotetra(3-hydroxyphenyl) porphyrin and Photofrin II were both localized in the nuclear membrane and other membrane structures, but could not be found inside the nuclei. Light exposure of cells at 1 degrees C in the presence of the sensitizers induced DNA double-strand breaks. The length distributions of DNA fragments were determined by pulsed field gel electrophoresis. Because DNA damage is produced mainly via singlet oxygen diffusing less than 0.1 microns from the sensitizer, DNA double-strand breaks were supposedly produced within this distance of the nuclear membrane. Consistent with this, with prolonged illumination and with increasing concentrations of sensitizer the distribution of DNA fragment lengths reached a plateau level. In contrast, with the hydrophilic, intranuclear sensitizer meso-tetra(4-sulphonatophenyl)porphyrin, no such plateau level was found. The plateau distributions of DNA fragment lengths of different cell types had the same general shape with average fragment lengths ranging from 174 to 194 kilobasepairs. Particular genes, c-myc, fos and p53, were found on broad distributions of photocleaved fragment lengths. The results indicate that on each side of the genes the locus of the chromatin fibre situated close to the nuclear membrane, varied randomly.


Novel in-frame two codon translational hop during synthesis of bovine placental lactogen in a recombinant strain of Escherichia coli.

A recombinant Escherichia coli strain was constructed for the overexpression of bovine placental lactogen (bPL), using a bPL structural gene containing 9 of the rare arginine codons AGA and AGG. When high level bPL synthesis was induced in this strain, cell growth was inhibited and bPL accumulated to less than 10% of total cell protein. In addition, about 2% of the recombinant bPL produced from this strain exhibited an altered trypsin digestion pattern. Amino acid residues 74 through 109 normally produce 2 tryptic peptides, but the altered form of bPL lacked these two peptides and instead had a new peptide which was missing arginine residue 86 and one of the two flanking leucine residues. The codon for arginine residue 86 was AGG and the codons for the flanking leucine residues 85 and 87 were TTG. When 5 of the 9 AGA and AGG codons in the bPL structural gene were changed to more preferred arginine codons, cell growth was not inhibited and bPL accumulated to about 30% of total cell protein. When bPL was purified from this modified strain, which included changing the arginine codon at position 86 from AGG to CGT, none of the altered form of bPL was produced. These observations are consistent with a model in which translational pausing occurs at the arginine residue 86 AGG codon because the corresponding arginyl-tRNA species is reduced by the high level of bPL synthesis, and a translational hop occurs from the leucine residue 85 TTG codon to the leucine residue 87 TTG codon. This observation represents the first report of an error in protein synthesis due to an in-frame translational hop within an open reading frame.


Selective decontamination of the digestive tract as an infection-control measure in intensive care unit patients.

Infection is responsible for a large percentage of morbidity and mortality in intensive care unit (ICU) patients. Conventional infection-control measures are directed at decreasing infection by exogenous sources and have had variable success in significantly reducing nosocomial infection rates. Selective gastrointestinal decontamination with topical nonabsorbable antibiotics attempts to reduce infection by eliminating intestinal mucosal colonization by pathogenic microorganisms. These antibiotics are selectively bactericidal against gram-negative organisms and yeasts, thereby leaving the normal flora (mainly anaerobes) unharmed. In the majority of clinical trials, selective decontamination effectively reduced colonization and infection among ICU patients, with the most significant reductions observed in gram-negative respiratory infections. Resistance to the antimicrobials was not documented in the majority of trials; however, follow-up periods were minimal and may not have been adequate to detect selection of resistant strains. Reductions in infection do not alter mortality; however, patients without significant underlying disease appear to be the subgroup that will most likely benefit.


Pharmacodynamic factors of antibiotic efficacy.

The primary focus of the pharmaceutical industry in past years has been on developing more potent antibiotics rather than on establishing optimum therapy with currently available agents. Concepts that can be used to tailor patient- and pathogen-specific antimicrobial regimens include concentration-dependent killing, concentration-independent killing, and postantibiotic effect. It is possible to administer single daily doses (SDD) of aminoglycosides; however, a fixed SDD regimen cannot meet the goals for therapy in all patients. Instead, it is necessary to consider both pharmacodynamic concepts and pharmacokinetic principles. Even with tailored, patient-specific regimens, however, limitations exist with antibiotic therapy alone. Immunotherapy, used as an adjunct to antimicrobial therapy, may play a role in improving patient outcomes.


The role of the fluoroquinolones.

Over the past decade, the quinolone antimicrobial class has enjoyed a renaissance with the emergence of the fluoroquinolone subclass. Norfloxacin, ciprofloxacin, ofloxacin, enoxacin, and lomefloxacin have the advantages of broad antimicrobial activity profiles including gram-positive and -negative aerobes, favorable pharmacokinetic profiles including substantial oral bioavailability and extensive tissue distribution, and in general, favorable safety profiles. As clinical experience accumulates, our understanding of their optimum roles will become more refined. In six instances, these agents may be preferred over currently available agents: complicated urinary tract infections, empiric therapy of suspected bacterial gastroenteritis, eradication of the Salmonella carrier state, respiratory exacerbations due to Pseudomonas aeruginosa in patients with cystic fibrosis, invasive external otitis, and chronic gram-negative bacillary osteomyelitis. The efficacy and convenience of these agents for the treatment of a broad range of infections have already resulted in their extensive use. Such use carries the risk of selection pressure for the development of resistance and the adverse consequences of increased cost over less expensive, equally effective alternatives. The use of the fluoroquinolones should focus on infections where there is demonstrated benefit of these agents over conventional agents or infections for which there are few or no alternatives.


Problems and dilemmas of antimicrobial resistance.

An important obstacle to the long-term efficacy of an antimicrobial agent is the appearance and spread of resistance to the agent. The fact that many antimicrobials are produced by microorganisms in nature may provide long-term selective pressure for the emergence of resistance in antibiotic-producing as well as -nonproducing organisms. Indeed, the rapidity with which many resistances have appeared after the introduction of a new antibiotic suggests that these resistance genes were already present somewhere in nature prior to clinical use. In the hospital setting, the most recent worrisome resistance traits to emerge include plasmid-mediated resistance to imipenem and to third-generation cephalosporins among nosocomial gram-negative bacteria, and the acquisition of resistance to vancomycin by enterococci. Methicillin-resistant staphylococci continue to be a problem and are increasingly resistant to numerous other agents such as rifampin and the newer fluoroquinolones. The most important resistances seen in community-acquired organisms include beta-lactam resistance in pneumococci and combined ampicillin and chloramphenicol resistance in Haemophilus influenzae. Shigellae resistant to essentially all commonly used oral agents are also a problem, particularly in developing countries. No end is in sight to the problem of antimicrobial resistance, and thus new strategies to prevent infections and control resistant organisms continue to be necessary.


Recent developments in vaccines and immunization practices.

Dramatic changes have been made in the recommended schedule for immunizations, and for a variety of reasons: greater understanding of risks associated with whole-cell pertussis vaccine; introduction of more immunogenic vaccines to prevent invasive disease caused by Haemophilus influenzae type B; a national epidemic of measles that affected many vaccinated individuals; and the failure of targeted use of vaccine in high-risk patients to reduce the occurrence of hepatitis B. Additional changes in recommended regimens can be anticipated as new products are introduced. However, for vaccines to have their greatest impact, improved adherence to recommended immunization practices is necessary.


Plasma endothelin-1 concentrations in the coronary sinus in dogs with artificially induced myocardial infarction.

We have previously reported the marked increase in plasma levels of endothelin-1 in patients with acute myocardial infarction (AMI). To investigate the effects of severe myocardial ischemia on the production of endothelin-1, plasma concentrations of endothelin-1 were measured by a sandwich-type enzyme immunoassay that we developed recently in both the coronary sinus and the aorta of dogs with artificially induced AMI. Dogs were anesthetized and chests were opened. The proximal left anterior descending coronary artery was completely occluded by ligation for 1 h and then was reperfused for 1 h. Throughout the experiment (at the end of occlusion for 1 h, at the beginning of reperfusion, at the end of reperfusion for 1 h), plasma endothelin-1 levels were not significantly altered either in the coronary sinus or in the aorta. The present findings indicate that severe myocardial ischemia itself does not affect the production of endothelin-1 in the coronary circulation of dogs.


Protective effect of cerulein on memory impairment induced by protein synthesis inhibitors in rats.

Previous studies have demonstrated that NMDA receptor antagonists and protein kinase C inhibitors induced marked memory impairment in rats, but that peripherally administered cerulein (CER) prevented these effects. In the present study, the effect of subcutaneously administered CER on amnesia induced by protein synthesis inhibitors was examined in passive and active avoidance responses and in the Morris water maze test. Intraperitoneal injection of the inhibitors produced marked memory impairment, but the effect was abolished by combined administration with CER. The effective dose of subcutaneously injected CER was, on a molar basis, three thousand- and six thousandfold less than the dose of anisomycin, and two hundred eighty- and three thousandfold less than the dose of puromycin in the passive and active avoidance response experiments, respectively. Similarly, in the Morris water maze test, behavioral disturbances produced by the protein synthesis inhibitors were abolished by CER. These results indicate the effectiveness of CER in preventing memory impairment induced by protein synthesis inhibitors.


Effects of pituitary adenylate cyclase activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) on the cardiovascular system in sheep.

The cardiovascular effects of PACAP and VIP were studied in intact conscious sheep; PACAP (0.008, 0.04, 0.2, and 1.0 nmol/min) and VIP (0.07, 0.2, 0.6, and 1.8 nmol/min) were infused in conscious sheep for periods of 10 min. For each peptide there was a dose-dependent increase in heart rate. At the highest doses tested, pulse pressure and mean arterial pressure tended to increase and decrease, respectively. However, only the decrease in mean arterial pressure following the highest dose of VIP reached significance. At the highest doses tested, heart rate increased nearly threefold during the infusion while mean arterial pressure declined by 18.5%. In individual animals the decrease in blood pressure and increase in heart rate occurred simultaneously, so that we were unable to conclude whether the increase in heart rate was due to a baroreceptor reflex.


Orcokinin: a novel myotropic peptide from the nervous system of the crayfish, Orconectes limosus.

A myotropic peptide, named orcokinin, was isolated from approximately 1200 abdominal nerve cords of the crayfish, Orconectes limosus. Its amino acid sequence was determined as follows: Asn-Phe-Asp-Glu-Ile-Asp-Arg-Ser-Gly-Phe-Gly-Phe-Asn. This structure was confirmed by synthesis. There is no sequence similarity to any known neuropeptide. Orcokinin exhibits high potency on the crayfish hindgut, enhancing both frequency and amplitude of spontaneous contractions. The threshold of biological activity in vitro was determined to be approximately 5 x 10(-11) M.


Gi protein mediates adenylate cyclase inhibition by neurohypophyseal hormones in fish gill.

Adenylate cyclase activity was measured on membrane fractions from the gill epithelium of rainbow trout Salmo gairdneri. Basal and glucagon-stimulated activities responded negatively to homologous neurohypophyseal peptides (arginine-vasotocin and isotocin). This inhibitory effect was totally abolished in the presence of pertussis toxin (IAP). The guanine nucleotide dependence of the enzyme was further explored by using GTP, GDP, and their stable analogs Gpp(NH)p, GTP gamma S, and GDP beta S. The results suggest that neurohypophyseal peptides at low concentrations inhibit the adenylate cyclase system directly by way of a Gi-protein, thus implying the intervention of a new type of membrane receptor for these hormones in fish gills.


Isolation of Leu-Pro-Pro-Gly-Pro-Leu-Pro-Arg-Pro-NH2 (Antho-RPamide), an N-terminally protected, biologically active neuropeptide from sea anemones.

Using a radioimmunoassay against the C-terminal sequence Arg-Pro-NH2 (RPamide), we have isolated the peptide Leu-Pro-Pro-Gly-Pro-Leu-Pro-Arg-Pro-NH2 (Antho-RPamide) from an extract of the sea anemone Anthopleura elegantissima. Antho-RPamide is located in neurons of sea anemones. Application of low concentrations of Antho-RPamide to tentacle preparations of sea anemones strongly increased the frequency and duration of spontaneous contractions, suggesting that this peptide is involved in neurotransmission. Antho-RPamide has a free N-terminus, yet its X-Pro-Pro sequence makes it relatively resistant to degradation by nonspecific aminopeptidases. Thus, we have discovered another strategy by which sea anemones protect the N-termini of their bioactive neuropeptides.


C-type natriuretic peptide immunoreactivity in human breast vascular endothelial cells.

The present study was undertaken to determine the presence of CNP immunoreactivity in human breast tissue (n = 9). Immunohistochemical staining of breast tissue revealed the presence of CNP immunoreactivity localized to vascular endothelial cells. This study demonstrates for the first time that CNP immunoreactivity is present in humans. Based upon the knows biological actions of CNP, these findings suggest that CNP may function as part of an endothelium-derived vasoregulatory system.


D-Pen2-[D-Pen5]enkephalin impairs acquisition and enhances retention of a one-way active avoidance response in rats.

We reported previously that D-Pen2-[D-Pen5]enkephalin (DPDE), a delta-opioid receptor selective analog of Leu-enkephalin, impairs acquisition of an automated jump-up avoidance response in rats and acquisition of a one-way active avoidance response in mice. In the present study we investigated the effects of DPDPE on one-way avoidance conditioning in rats. The rats received two escape-only trials on day 1 and eight additional training trials on day 2. DPDPE (1.16 micrograms/kg IP) administered prior to training on day 2 impaired acquisition of the avoidance response. On the other hand, DPDPE (0.332 microgram/kg IP) administered following presentation of the two escape-only trials on day 1 significantly enhanced retention, as measured by improved one-way active avoidance performance on day 2. These results indicate that activation of delta-opioid receptors by DPDPE has a modulatory effect on acquisition and retention of aversively motivated performance.


Endogenous corticotropin-releasing factor modulates feeding induced by neuropeptide Y or a tail-pinch stressor.

Previous work has characterized an anorexic action for endogenous, central nervous system corticotropin-releasing factor (CRF). Central injection of CRF decreases food intake induced pharmacologically by various appetite stimulants and a CRF antagonist attenuates restraint stress anorexia. Also, stressful physiological stimuli that are relevant to ingestive regulation, such as glucoprivation and protein nutrient deficiency, activate CRF systems. The present experiments examined the effects of exogenously administered CRF and a CRF antagonist, alpha-helical CRF(9-41), on spontaneous feeding induced by neuropeptide Y (NPY) and by a tail-pinch stressor. Pretreatment with a low dose of the CRF antagonist (1 microgram ICV) enhanced the hyperphagia induced by NPY while reducing the latency to begin feeding and increasing the duration of eating during tail pinch. Higher doses of alpha-hel CRF (5 and 25 micrograms ICV) exhibited diminishing or opposite effects. In contrast, CRF pretreatment (0.02, 0.1, and 0.5 microgram ICV) blocked the acquisition of tail-pinch feeding. Hence, while CRF administration impairs intake in these and other feeding paradigms, alpha-hel CRF actually facilitated dose dependently the intensity of the feeding response to NPY and tail pinch. These results suggest that endogenous CRF systems may play a role in modulating excessive feeding under conditions of evoked appetite and that brain CRF systems regulate feeding when excessive intake threatens to compromise the performance of other noningestive behaviors.


Trypsin inhibitor and maternal reunion increase plasma cholecystokinin in neonatal rats.

Intragastric soybean trypsin inhibitor increased plasma CCK bioactivity by 87% in nondeprived, 9-12-day-old rat pups. Reunion with the dam for 1 h after overnight maternal deprivation also increased plasma CCK significantly. These results demonstrate that CCK can be released from the small intestine of rats as early as postnatal day 9.


Guanine nucleotide regulation of VIP binding to rat peritoneal macrophage membranes.

In the present study, we have examined the effect of guanine nucleotides on VIP binding to rat peritoneal macrophage membranes. Both guanosine 5'-triphosphate (GTP) and its nonhydrolizable analog guanosine 5'-beta, Y-imidotriphosphate [Gpp(NH)p] inhibited, in a dose-dependent manner, the VIP binding to its specific binding sites. Half-maximal inhibition (IC50) was observed at 5.4 +/- 0.5 microM GTP. The inhibitory effect of GTP was due to an increase of the dissociation rate of peptide bound to membranes. The specificity of the binding inhibition was assessed from the lack of action of the other nucleotides tested. These results directly suggest the coupling of VIP binding sites with guanine nucleotide binding proteins in rat peritoneal macrophage membranes.


Intracerebroventricularly administered atrial natriuretric peptide (ANP) antiserum attenuates fear-motivated learning behavior in rats.

Previous studies have demonstrated that rANP(1-28) administered into the lateral cerebroventricle facilitates consolidation of the passive avoidance response and delays extinction of the active avoidance response in fear-motivated learning in rats. To study the role of endogenous ANP in the same learning processes, the effects of different dilutions of ANP antiserum were investigated following their intracerebroventricular administration to rats. At dilutions of 1:40 and 1:60, the ANP antiserum attenuated consolidation of the passive avoidance response. It also facilitated extinction of the active avoidance response at a dilution of 1:2. The results suggest that endogenous ANP might be considered a modulating agent in the brain, and is involved in the learning processes and memory trace formation, since intracerebroventricularly administered antiserum against ANP attenuated fear-motivated learning behavior in the experimental animals.


Protein synthesis in the hippocampus associated with memory facilitation by corticotropin-releasing factor in rats.

The present study used pharmacological, biochemical, and behavioral methods to examine the role of protein synthesis in the hippocampus in memory processes of a passive avoidance learning in rats. Results indicated that corticotropin-releasing factor (CRF) significantly improved memory retention in rats. Both cycloheximide (CHX) and actinomycin-D (ACT-D) impaired memory at high doses. At doses of CHX and ACT-D that did not affect memory alone, they both antagonized the memory-enhancing effect of CRF. Biochemically, there were specific increases in the optical density of three protein bands in the cytosolic fraction of hippocampal cells in rats showing good memory. There were also marked increases in the optical density of two protein bands in the nucleus fraction of the same animals. Similar results were observed in animals injected with CRF. However, no significant protein alteration was observed in animals receiving stress. These results together suggest that there are new protein syntheses in the hippocampus that are specifically associated with passive avoidance learning in rats.


Benzodiazepine suppression of corticotropin-releasing factor (CRF)-induced beta-endorphin release from rat neurointermediate pituitary.

Dopamine and gamma-aminobutyric acid (GABA) inhibit POMC peptide release from the pituitary intermediate lobe, via interaction with D2 or GABA-A/benzodiazepine receptors. Here, we examined the effects of an antianxiety triazolobenzodiazepine, adinazolam, on corticotropin-releasing factor (CRF)-stimulated POMC peptide secretion from the rat neurointermediate pituitary. Neurointermediate lobes (NILS) were incubated with CRF (10(-7) M), then adinazolam (10(-8) or (10(-9) M) was added, with CRF remaining in the medium. Aliquots were removed at 15-min intervals and frozen for radioimmunoassay of beta-endorphin. Adinazolam alone did not significantly affect secretion as compared to controls or CRF alone. Adinazolam incubated with CRF led to significant inhibition of beta-endorphin secretion, as compared to CRF alone. In addition, adinazolam was as effective as dopamine or the CRF antagonist, alpha-helical CRF, in preventing CRF-induced beta-endorphin release. Adinazolam appears to act directly on the pituitary to suppress hormone release induced by a stress-related hypothalamic peptide.


[Evaluation of the usefulness of analysis of beta-glucuronidase levels in patients with superficial cancer and papilloma of the bladder].

Beta-glucuronidase activity in the blood serum, the urine, and tumour tissue has been assayed in patients with superficial bladder neoplasm and papilloma of the bladder prior to and after transurethral electroresection (TUR). Twenty five healthy subjects constituted a control group. It was shown that the activity of beta-glucuronidase may be a valuable test in the differential diagnosis of bladder neoplastic lesions as well as in the assessment of the results of therapy with transurethral electroresection.


[Histological structure of the testes in andropause].

A structure of the convoluted tubuli, spermatogenesis and number of Leydig's cells in the andropause have been analysed in dependence on the degree of symptoms intensity. A control group included otherwise healthy men with ++post-inflammatory azoospermia. A percentage of the convoluted tubuli with normal tissue (p < .002) and spermatogenesis (p < .001) has been significantly decreased in andropause. The number of Leydig's cells has not differed in andropause and in a control group (p < .05). No difference of significance have been noted in the structure of convoluted tubuli, spermatogenesis, and Leydig's cells number depending on the intensity of symptoms. FSH and LH levels have been significantly increased in andropause (p < .001). No relationship between FSH and LH levels and percentage of the abnormal convoluted tubuli has been observed. However there have been a relationship between FSH and LH levels and the number of abnormal convoluted tubuli with spermatogenesis inhibition and intensified clinical symptoms. There has also been a relationship between FSH and LH levels and Leydig's cells number in patients with marked symptoms of andropause.


[Development of biological value of sperm in delayed puberty].

Changes in the biological value of sperm depending on the time of the first ejaculation are presented. A control group included 194 boys with normal puberty in whom a biologic value of sperm was evaluated in dependence of the first ejaculation. In all time points a biological value of sperm was significantly worse in the delayed puberty than that in the control group. Twenty four months following the first ejaculation sperm was not normal in any case whereas in the control group normospermia prevailed in this period of time.


[Ureteral anastomosis by Nd:YAG laser light; experimental studies in dogs].

The results of experimental ureteral anastomoses with laser Nd:YAG are discussed. Cut ureters were anastomosed in all animals. Anastomosis consisted of the scar of the connective tissue covered with intermediate epithelium and scarring process was quicker, if modelling catheter was used.


Tests of adipsia and conditioned taste aversion following the intrahypothalamic injection of amylin.

Intrahypothalamic injection of amylin (AMY) was shown to reduce the intake of rat chow and water for 8 and 4 h, respectively, in schedule-fed rats. Amylin also reduced water intake to a much lesser degree in 24-h water-deprived rats. A test of the ability of AMY to form a conditioned taste aversion yielded no change in saccharin preference, as compared to controls treated with vehicle. These results suggest that although AMY has adipsic effects, the reduction in water is not of sufficient magnitude to cause the anorexia. In addition, the failure of AMY to support a conditioned taste aversion suggests that AMY does not cause anorexia by inducing malaise. Therefore, in addition to other metabolic effects, AMY may be involved in the control of food and water intake.


Isolation and primary structure of gastrin-releasing peptide from a teleost fish, the trout (Oncorhynchus mykiss).

Immunohistochemical studies have established that fish gastrointestinal tissues contain peptides with gastrin-releasing peptide (GRP)/bombesin-like immunoreactivity, but the molecular nature of this material is unclear. In this study, the most abundant peptide that was immunoreactive towards an antiserum raised against pig GRP was isolated in pure form from an extract of the stomach of the rainbow trout (Oncorhynchus mykiss). The primary structure of the peptide was established as: Ser-Glu-Asn-Thr-Gly-Ala-Ile-Gly-Lys-Val10- Phe-Pro-Arg-Gly-Asn-His-Trp-Ala-Val-Gly20-His-Leu-Met-NH2. Although this amino acid sequence is shorter than those of mammalian GRPs by four residues, the COOH-terminal dodecapeptide is identical to the corresponding region in pig GRP. The data indicate, therefore, that the predominant molecular form of GRP in the stomach of a teleost fish is structurally more similar to mammalian GRP than to the amphibian skin peptide, bombesin.


[Diagnosis of breast pathology in men].

Among pathological states of the breast in men the most frequently encountered is gynecomastia caused by glandular hypertrophy. Male breast carcinoma is an unfrequent condition. These and other diseases differential diagnosis with application of mammography is presented.


Stroke in adult polycystic kidney disease.

In order to assess the incidence of acute cerebrovascular events, 142 patients with adult polycystic kidney disease were retrospectively reviewed. Fourteen patients (9.8%) had 19 cerebral attacks. Six patients (4.2%) had intracranial haemorrhage attacks (three ruptured intracranial aneurysms and three cerebral haemorrhages). Ischaemic events occurred in nine patients (five cerebral infarctions and four transient ischaemic attacks). Patients with ischaemic attacks had a better outcome than patients with haemorrhagic events even when transient ischaemic attacks were excluded. Patients with ruptured intracranial aneurysms were younger. Cerebral complications are an important cause of morbidity and mortality in patients with adult polycystic kidney disease. They can prove disabling prior to or after dialysis and transplantation.


[Pharmacokinetics of urinary excretion of methotrexate (MTX) in patients with malignant tumors].

Pharmacokinetics of methotrexate renal elimination was investigated in patients with cancer given a single intravenous injection. Elimination coefficient ke (0.151 + 0.05 h-1) and half-life t0.5 (5.3 +/- 2.9 h) were calculated. A percentage of methotrexate dose eliminated with the urine was determined (26.0-97.1%) in both unchanged and bound forms. It was found that methotrexate is eliminated in the form of glucuronates and sulfates (2-25% of the administered dose). It was also noted, that pH of the urine exerts an effect on the amount of eliminated methotrexate.


Absence of potentiation of the skin response to intradermal bradykinin by a long-acting angiotensin converting enzyme inhibitor, trandolapril, at conventional antihypertensive dosage in human volunteers: a double-blind, randomized, cross-over, placebo-controlled trial.

A double-blind, randomized, cross-over, placebo-controlled study was carried out to determine the extent and duration of potentiation of the action of bradykinin introduced intradermally by a long-acting novel angiotensin converting enzyme (ACE) inhibitor, trandolapril. The investigations were performed in a temperature and humidity-controlled laboratory. Intradermal injections of 1 microgram, 2.5 micrograms and 5 micrograms of bradykinin and normal saline (as control) were made into the forearm skin of eight healthy normotensive male volunteers aged 21-33 years (mean 28 years) at baseline, 2, 4, 8, 24, 48, 72 and 96 hours after either 2 mg trandolapril or placebo given orally. Skin blood flow outside the induced weal was monitored by laser Doppler flowmetry (mean of recordings at four sites adjacent to the weal within the flare area). Flare area and weal volume were also measured. Trandolapril reduced the mean arterial pressure. However, there was no evidence that this activity was associated with a potentiation of the cutaneous action of bradykinin. In conclusion, it would appear that potentiation of the action of bradykinin may not be an important contributing factor to the fall in total peripheral vascular resistance associated with ACE inhibition in humans in the control of hypertension.


Safe use of streptokinase in myocardial infarction in patients aged 75 and over.

We have given streptokinase to 73 patients aged 75 and over admitted to medical admission wards for elderly people using strict exclusion criteria. This was safe and free from significant adverse events by comparison with other studies. The average age of the patients was 78.2 years so they formed a relatively young group compared with all patients over 75. There was a relatively long delay between presentation at the hospital and receipt of treatment.


[Errors in the diagnosis of testicular torsion].

Two cases of testicular torsion are presented. The diagnosis was late. It led to the castration of testicular necrosis in both patients. This pathology is recognizable most easily within the first hours following onset. Later, there are still chances to spare affected organ. This report indicates the importance of the first contact with physician and his prompt intervention.


Chronic idiopathic anhydrosis--a rare cause of heat stroke.

A 27 year old man presented with heat stroke following exposure to a humid, hot environment in the absence of physical exertion. Investigation revealed the presence of generalized anhydrosis without evidence of an associated disease. Although chronic idiopathic anhydrosis is rare, this entity should be considered in cases of unexplained heat intolerance and heat stroke.


Elevated serum parathyroid hormone related protein and 1,25-dihydroxycholecalciferol in hypercalcaemia associated with adult T-cell leukaemia-lymphoma.

Hypercalcaemia occurs in up to 80% of patients with adult T-cell leukaemia-lymphoma (ATLL) associated with human T-cell leukaemia virus-1 infection. Elevated serum levels of 1,25-dihydroxycholecalciferol, implicated in the pathogenesis of hypercalcaemia in lymphoma, and of parathyroid hormone-related protein (PTHrP), which is associated with hypercalcaemia of several solid malignancies, were demonstrated in a patient with ATLL hypercalcaemia. Treatment with bisphosphonates reduced the serum calcium but had no significant effect on the serum PTHrP levels. This case supports recent in vitro evidence for enhanced PTHrP expression in ATLL tumour cells and suggests that more than one tumour cell product may be involved in the pathogenesis of ATLL hypercalcaemia.


Fatal haematemesis due to benign retrosternal goitre.

The development of a goitre in the retrosternal space may result in many different symptoms due to local compression. We describe a case in which such a goitre resulted in full-thickness ulceration of the oesophagus, which presented as a fatal haematemesis. We believe that such a complication has not been previously reported.


Acute myocardial infarction related to smoke inhalation and myocardial bridging.

A previously healthy 26 year old woman who was exposed to smoke during a house fire developed acute anterior myocardial infarction complicated by ventricular fibrillation. Subsequent left ventriculography confirmed anterior infarction, but coronary arteriography was normal apart from myocardial bridging over a segment of the left anterior descending artery. The development of acute myocardial infarction in this patient suggests that, in the presence of bridging, carbon monoxide inhalation may cause regional infarction.


Yersinia enterocolitica endocarditis on a prosthetic valve.

Yersinia entercolitica endocarditis has rarely been described before. This is the first report of prosthetic valve Yersinia enterocolitis endocarditis, complicated by infected brain embolization. The patient, however, completely recovered after 6 weeks of combined therapy with ceftriaxone and gentamicin.


Massive haemorrhage due to ulcerative colitis presenting as melaena.

We present a patient with known ulcerative colitis who presented with massive lower gastrointestinal bleeding in the form of melaena. Extensive investigations indicated that the source of blood loss was only from the colon, was attributable to the colitis, and settled when the colitis was treated with steroids. Melaena may be due to blood loss from the colon.


Naproxen-associated vasculitis.

Three cases of digital vasculitis attributable to naproxen ingestion are reported. The vasculitic changes were reversed by withdrawal of the drug. These three cases emphasize the need to consider drug sensitivity as a cause of unexplained digital vascular lesions.


Different regiospecificity in the hydroxylation of the antidepressant desmethylimipramine between rat brain and liver.

Incubation of the tricyclic antidepressant desmethylimpramine (DMI) with rat liver or brain microsomes in the presence of NADPH or t-butyl-hydroperoxide (TBH) revealed different regiospecificities in the hydroxylation reactions between the tissues. In brain preparations 10-OH-DMI was formed in reactions supported by NADPH or TBH, whereas in the latter case also an unidentified metabolite could be detected. Inclusion of exogenous NADPH-cytochrome P450 reductase in the brain preparations caused a 10-fold higher rate of 10-hydroxylation but no 2-OH-DMI could be detected. By contrast, liver microsomal preparations in the presence of NADPH catalyzed formation of both 2- and 10-OH-DMI, whereas only 10-OH-DMI was formed in TBH-supported reactions. The results indicate that antidepressant drugs can be metabolized in brain with different stereospecificity as compared to liver.


Enrichment of metabolites in the cerebrospinal fluid of cod (Gadus morhua) following oral administration of hexachlorobenzene and 2,4',5-trichlorobiphenyl.

The disposition of 14C-labelled hexachlorobenzene (HCB) and 2,4',5-trichlorobiphenyl (triCB) was studied in cod (Gadus morhua) and rainbow trout (Oncorhynchus mykiss). For both compounds tape section autoradiography revealed substantial amounts of radiolabelled material in the central nervous system (CNS) of cod, whereas only traces of radioactivity were observed in the CNS of rainbow trout. Furthermore, an enrichment of radiolabelled compound in the cerebrospinal fluid (CSF) was observed in the cod, whereas no radioactivity could be detected in the CSF of rainbow trout. According to autoradiography, the CNS of cod dosed with HCB contained the parent compound, whereas the major part of radioactivity in CSF was due to HCB metabolites. Thin-layer chromatography of extracts from cod dosed with triCB showed the presence of parent compound in the CNS, whereas part of the radioactivity in the CSF was due to triCB metabolites. The activities of cytochrome P-450 and UDP-glucuronosyltransferase in the CNS of cod and rainbow trout were determined in microsomal and mitochondrial fractions. Both species expressed activities which were in the same order of magnitude as those reported for the corresponding fractions from rat brain. Incubation of triCB with cod brain mitochondria and microsomes resulted in the formation of two polar metabolites. It is suggested that cod may be more vulnerable than rainbow trout regarding neurotoxicological effects of HCB, triCB and related environmental pollutants.


Responses of hepatic xenobiotic metabolizing enzymes of mouse, rat and guinea-pig to nickel.

The effects of nickel (Ni) on hepatic monooxygenase activities (aniline 4-hydroxylase, AH; ethylmorphine N-demethylase, EMND; aminopyrine N-demethylase, AMND), cytochrome P-450, cytochrome b5, microsomal haem and reduced glutathione (GSH) levels, and glutathione S-transferase (GST) activities toward several substrates (1, chloro-2-4-dinitrobenzene, CDNB; 1,2 dichloro-4-nitrobenzene, DCNB; ethacrynic acid, EAA) in mice, rats and guinea-pigs were studied. Ni (59.50 mg NiCl2.6H2O/kg, subcutaneously) was administered to the animals 16 hr prior to sacrifice. Ni significantly inhibited AH, EMND, AMND activities, and decreased cytochrome P-450, cytochrome b5 (except in the livers of rats), and microsomal haem levels in the livers of all the animal species examined. However, the depressions were more profound in livers of mice than in those of the other two species. The hepatic GSH level was significantly inhibited in mice whereas no alteration was observed in rats. In guinea-pigs, the hepatic GSH level was significantly increased by Ni. The hepatic GST activity toward the substrate CDNB was significantly depressed in mice, unaltered in rats and significantly increased in guinea-pigs by Ni. The hepatic GST activity toward DCNB was significantly inhibited in mice whereas no significant alteration was observed in rats. In guinea-pigs, Ni caused significant increase in hepatic GST activity for DCNB. However, hepatic GST activity toward EAA was significantly inhibited in mice whereas significantly increased in rats and guinea-pigs. These results seem to indicate that i) there exists quantitative, but not qualitative, differences among the hepatic monooxygenases of rodents in response to Ni, mice being more sensitive than rats and guinea-pigs, ii) the influence of Ni on hepatic GSH level varies depending on the animal species and iii) the hepatic GSTs of rodents are differentially regulated by Ni.


Production of limbic motor seizures and brain damage by systemic and intracerebral injections of paraquat in rats.

The behavioural and neuropathological effects of both systemic and intrahippocampal injections of paraquat dichloride (1,1'-dimethyl 4,4'-bipyridinium dichloride) were studied in rats. Paraquat (0.1-1.0 mumol) injected into the dorsal hippocampus, produced limbic motor seizures within a few minutes of injection followed by neuronal damage in the CA1 and CA3 pyramidal cell layers, pyriform cortex, dentate granule cell layer and in the hilus fascia dentata at 24 hr (n = 9 rats). A smaller dose of paraquat (10 nmol) was ineffective. The effects of intrahippocampal injections of paraquat (1 mumol) were prevented by administering it together with atropine (50 nmol; n = 6 rats) or by giving it 60 min. after MK 801 (0.3 mg.kg-1 intraperitoneally). Systemic injections of paraquat (20-100 mg.kg-1) also produced forelimb clonus and rearing in 10 out of 15 animals. Neuronal cell death was found 24 hr later in 9 of these rats and was restricted to the pyriform cortex, the brain region with the highest concentrations of paraquat. Atropine (150 mg.kg-1 intraperitoneally given 60 min. previously) completely prevented the motor seizures but cell death still occurred in 2 of the 6 animals tested. In conclusion, both systemic and intrahippocampal injections of paraquat produced behavioural excitation accompanied 24 hr later by brain damage and antagonist studies suggested involvement of muscarinic and NMDA receptors in the neurotoxic mechanism.


Evidence of active transport of cadmium complexing dithiocarbamates into renal and hepatic cells in vivo.

A study was made of the effects of certain inhibitors of transport systems on the actions of four cadmium (Cd) complexing N,N-disubstituted dithiocarbamates (DTCs) in mobilizing murine renal and hepatic Cd in vivo. Probenecid, the prototypical antagonist of organic anion transport in the kidney, when given 1 hr prior to each DTC, sharply suppressed the DTC-induced reduction of renal Cd but was virtually without effect on mobilization of Cd from liver. Sulfinpyrazone, which blocks tubular reabsorption of uric acid and also inhibits transport of a variety of organic acids, inhibited markedly the mobilization of both renal and hepatic Cd by DTCs. Phlorizin, an inhibitor of tubular sugar reabsorption, did not affect the Cd mobilizing actions of DTCs in any consistent fashion. We propose that the high degree of selectivity of DTCs in mobilizing renal and hepatic Cd is dependent, at least in part, upon active transport of DTCs into these tissues via the organic anion transport systems. This report presents the first evidence that compounds of the (R)2NCSS- class may gain access to intracellular space by an active, carrier-mediated process.


Failure of addition of lithium to imipramine to enhance activity in rats or mood in normal volunteers.

Lithium powerfully augments the effects of imipramine in resistant depression. We treated four groups of rats for five weeks with (1) saline alone, (2) saline followed by lithium, (3) imipramine alone, and (4) imipramine followed by lithium. There was no augmentation of activity by lithium. Normal human volunteers took imipramine 75 mg daily for three weeks, followed by imipramine 75 mg daily together with lithium 900 mg daily for another ten days. There was no elevation of mood after the addition of lithium. Lithium augmentation of antidepressants apparently requires a pre-existing neurochemical-behavioral disturbance.


Serotonin, carbohydrates, and atypical depression.

At least three categories of atypical depression have been described. The hysteroid dysphoria is characterized by repeated episodes of depressed mood in response to feeling rejected, and a craving for sweets and chocolate. Two other issues are characterized by a cyclical occurrence of changes of mood and appetite, i.e., the late luteal phase dysphoric disorder (DSM-III-R, appendix), or "the premenstrual syndrome" (PMS), and the major depression with seasonal pattern (DSM-III-R), or seasonal affective disorder (SAD). The reactive mood changes are frequently accompanied by features as hypersomnia, lethargy and increased appetite, particularly with a preference for carbohydrates. Central serotonin pathways participate in the regulation of mood and behavioural impulsivity, and modulate eating patterns qualitatively and quantitatively. Depressives with PMS og SAD benefit, in general, from treatments with serotonin potentiating drugs, suggesting that brain serotonin plays a role in the pathophysiology. Ingestion of carbohydrates increases the plasma ratio of tryptophan to other large neutral amino acids in man and animal, and the serotonin synthesis in the rat brain. Based on these findings it has been suggested that the excessive carbohydrate intake by patients with PMS and SAD reflects a self-medication that temporarily relieves the vegetative symptoms via an increased central serotonergic activity.


Light therapy of depression; basal and clinical aspects.

The effects of treatment with bright light in different forms of depressive conditions are described. The therapeutic mode rests on the hypothesis that they will normalize disturbed diurnal rhythms. The results have been more favourable when light has been given in the morning compared with in the evening, and in patients with seasonal depression rather than in those with non-seasonal illness.


[Visceral leishmaniasis in HIV infection. A totally opportunistic infection].

Visceral leishmaniasis occurring in immunocompromised patients, and in particular during HIV infection, has been described in recent years and differs from the usual Mediterranean kala-azar as encountered in France. In order to define the clinical, diagnostic and therapeutic features of the HIV-Leishmania spp. co-infection, we report 8 new cases and compare them with data from the literature. The co-infection occurs at any stage of HIV infection, usually in drug addicts using intravenous injections. Clinical manifestations, such as fever, weight loss, liver and spleen enlargement and polyadenopathy, and laboratory findings (cytoponia, inflammatory syndrome) are generally present but not specific during the HIV infection course. Moreover, some gastrointestinal and pleuropulmonary forms of the co-infection are misleading. Leishmaniasis serology is negative in 50 percent of the patients. In most cases the diagnosis is provided by detection of the parasite in bone marrow samples. Culture must be systematic, and samplings must be repeated if they are negative. The first-line treatment consists of pentavalent antimony. Almost 80 percent of the patients respond to this treatment, but relapses occur in 50 percent of the cases. This high risk of relapse and the opportunistic behaviour of leishmaniasis justify a prophylaxis of relapses.


[Circulatory changes of the middle cerebral artery during syncopes produced by the head-up tilt test].

Velocity of the middle cerebral artery was recorded with transcranial pulsed doppler in 10 neurally-mediated syncopes elicited by 60 degrees head-up tilt test. Mean arterial blood pressure decreased by -36 +/- 16 percent (P < 0.0001) and heart rate by -6 +/- 27 percent (P < 0.05). Mean middle cerebral artery velocity decreased by -48 +/- 16 percent (P < 0.0001); Pourcelot's resistance index increased by 74 +/- 47 percent (P < 0.0001) and Gosling's pulsatility index by 218 +/- 111 percent (P < 0.0001). However, resistance normalized with mean arterial pressure showed no significant increase (+ 14 +/- 28 percent; NS). The decrease in diastolic velocity as well as mean arterial blood pressure and heart rate was significantly lower when loss of consciousness occurred. Contrary to those of other authors, our results do not support the hypothesis that syncopes result from a paradoxical cerebral vasoconstriction since no significant changes were observed in resistance normalized with mean arterial pressure. Thus, decrease in cerebral perfusion is likely to be the result of a decrease in cerebral perfusion pressure.


[Relationship between gastroesophageal reflux and severe malaise in infants].

The relationship between gastroesophageal reflux (GER) and sudden infant death syndrome (SIDS) has been widely investigated. Reflux-induced apnoea is triggered through a vagal mechanism. During acute phases of sleep, the different means of protection of the upper respiratory tract are blunted, awakening reactions are cancelled or delayed and hypoxemia occurs rapidly. GER could play a leading part in SIDS occurring during this acute phase of sleep. Numerous studies are needed to further dismantle the link between SIDS and GER. In children with severe malaise, a systematic search for GER is mandatory.


[Blastocystis hominis: in search of a disease, a misunderstood organism].

Blastocystis hominis is a micro-organism which remains somewhat mysterious. Having defined its present position in the classification of Protozoa, the authors describe its ultrastructure and morphology. Its epidemiology and pathogenicity are discussed in the light of experimental studies and human clinical data, especially in AIDS patients. Metronidazole seems to be the most active drug against this organism, but extreme caution must be exerted when the possible pathogenic property of B. hominis is discussed.


[Treatment of chronic heart insufficiency with dobutamine. Value and limitations].

Most positively inotropic drugs are available only as intravenous injection, which restricts their use in chronic heart failure. A single and brief infusion of dobutamine--a synthetic catecholamine and potent beta 1-adrenoreceptor agonist--provides a clinical improvement which may last for several weeks. On the other hand, tachyphylaxis to dobutamine may develop after a several days' infusion, so that the drug gradually loses its effectiveness. In patients with chronic heart failure, intermittent infusions of dobutamine result in sustained clinical improvement in more than 50 percent of the cases. The relative preservation of beta-adrenoceptors seems to play a role in the beneficial effects of intermittent infusions. The most significant side-effects of dobutamine are ventricular rhythm disorders. The practical applications and supervision of repeated dobutamine infusions in chronic heart failure are detailed.


[Severe acute asthma in adults in black Africa].

A prospective study has been conducted in an intensive care unit of West Africa in order to determine the clinical and laboratory features of severe acute asthma in black Africans. The study concerned 55 episodes of severe acute asthma, with PaCO2 above 45 mmHg, in 42 patients (26 men and 16 women, mean age 35 +/- 3 years). A triggering factor was found in only 36 percent of the cases. None of the patients were using beta-adrenergic stimulants as maintenance therapy. The mean duration of asthmatic attacks prior to hospitalization was 49 +/- 7 hours. Three patients had cardiorespiratory arrest on admission. Mechanical ventilation was necessary on 12 occasions (initially in 4 and secondarily in 8). Four patients died. It would appear from this study that severe acute asthma in black Africans is characterized by a prolonged onset and by a frequent need for mechanical ventilation, suggesting a physiopathological mechanism different from that described in industrialized countries.


[Chester-Erdheim's disease. A case].

We report the 32nd case of a multivisceral form of Erdheim-Chester disease. This exceptional pathology is a diffuse xanthogranulomatosis which comes within the scope of histiocytosis. The originality of this case is due to cerebral localizations and to the fact that some symptoms have been observed for a long time: diabetes insipidus, exophthalmos and stubborn intertrigo.


[Fetal and neonatal immune thrombocytopenias. Study group "Mother-child immune thrombopenias"].

Neonatal thrombocytopenia has benefited from the advances achieved during the last few years in platelet immunology and foetal therapy. The major risk of the disease is cerebral haemorrhage resulting in death or neurological sequelae. Establishing the aetiological diagnosis of immune thrombocytopenia makes it possible nowadays to apply the appropriate treatment and eventually to take care of future pregnancies. Treatments in utero of foeto-maternal alloimmunization have radically altered the natural course of foetal thrombocytopenia, thereby permitting the management of pregnancies at risk. On the other hand, so far no prenatal treatment has proved to be effective against thrombocytopenia due to maternal autoimmunity.


[Insulinotropic factors in health and disease].

Reviews in brief the studies of the effects of some non-glucose regulators of various origins on pancreatic insulin secretion mediated by endocrine, paracrine, and neurocrine mechanisms, carried out in this laboratory. Model experiments with primary monolayer cultures of isolated islet cells have helped demonstrate a direct insulinotropic effect of STH, TRH, C-terminal tetrapeptide cholecystokinin, opioid peptides and blood plasma of patients with insulin-dependent diabetes mellitus. The findings evidence that the insulinotropic effect of the blood serum of patients with type I diabetes may be associated with both stimulation and suppression of the functional activity of the cultivated islet cells. This latter type of effect influences the basal and glucose-stimulated secretion of insulin. The destructive effect of the plasma of patients with insulin-dependent diabetes on the function of islet cell culture is confirmed by the presence of autoantibodies to islet cell surface antigens in the plasma of 53-55% of the examined patients and by a cytotoxic effect in 45% of cases.


[Comparative characterization of radioimmunologic and non-isotopic methods of hormonal analysis].

Measurements of 8 hormones (prolactin, FSH, LH, thyrotropic hormone--TTH, estradiol, hydrocortisone, thyroxine, and triiodothyronine--T3) were carried out by the Amerleit system and radioimmunoassay. The hormones were measured in the same blood plasma samples of patients with various endocrine conditions, admitted for examinations to the Endocrinology Center of the Russian Academy of Medical Sciences. Employment of the Amerleit system for hormonal analysis helps obtain the results compatible with the results of RIA for the majority of the measured hormones. The methods for measuring LH, estradiol and T3 are to be improved. The Amerleit system is highly productive and permits getting the results within 3 hrs. A trained laboratory assistant can measure the hormonal levels in 120-160 blood samples within a day. High efficacy of the technology is indispensable in realization of the screening programs. The absence of radioactivity, safety, high productivity, reliability, accuracy and good storage of the kits (up to 6-8 months) are the principal advantages of the Amerleit system over the existent radioimmunologic systems.


[Age-related features of the development and course of diabetic ketoacidosis].

Analysis of the causes of development, clinical features of and treatment strategy in diabetic ketoacidosis (DKA) in 457 diabetics of various age groups (16-39, 40-60, over 60) has revealed a more grave course of this condition in old patients. This may be explained largely by a combination of diabetes mellitus with coronary disease or brain ischemia, that impede timely detection of DKA, this resulting in delayed hospitalization and deterioration of the vital prognosis.


[Circadian and infradian rhythms of testosterone and aldosterone excretion in children].

Individual daily and many-day time course of hormonal excretion was studied in boys of various ages. Cosinor analysis was used to determine the parameters of circadian and infradian rhythms. Time course of the mesor and amplitude circadian rhythms of testosterone, aldosterone, and luteinizing hormone (LH) in 5 groups (from 4 to 28 years of age) evidenced changes of this rhythm with age. The aldosterone mesor rhythm reduced as the boy grew older till he reached the adolescence, whereas testosterone and LH mesor increased, this increase being particularly marked by adolescence as regards testosterone and by youth in what concerns LH. The rhythm amplitude (mesor %) of aldosterone and testosterone was the maximal in children aged 7-8, then it reduced; LH amplitude was the highest in adolescents aged 13-14. A 40-day investigation of testosterone and aldosterone excretion in boys and youths has revealed infradian rhythms with periods of 2.5 to 5.5 days. These rhythms were characterized by age-specific differences as to the mesor size and oscillation amplitude, not differing by the periods. Infradian rhythms with periods of 5 to 13.5 days and testosterone excretion rhythm 21-day long were detected in youths. These results permit a conclusion that the structure of these hormones circadian and infradian rhythms may serve to characterize the age-specific and individual features of the endocrine gland functioning.


[Study of the morphofunctional properties of cultured thyrocytes of newborn piglets with the purpose of determining the feasibility of their use for compensation of thyroid gland hypofunction].

The method for cultivation has been developed and morphofunctional characteristics of the newborn piglet thyrocytes studied in order to elucidate the possibility of using these cells for the compensation of the thyroid gland hypofunctioning. The results evidence viability of the cultivated thyrocytes and intactness of their thyroxine-secreting activity within 14 days. Addition of thyrotropin to the medium resulted in the accrement in the population of the active hormone-producing and follicle-producing cells, in reduction of the number of degenerating and pyknotic forms, in stimulation of thyroxine secretion, incorporation of 3H-leucin in thyrocyte protein, and in absorption and organification of 131I by these cells, this being the specific function of this gland, providing the adequate synthesis of thyroid hormones. The resultant thyrocyte culture may be used in clinical transplantology for the treatment of hypofunctional states of the thyroid.


Antibody response in Plasmodium vinckei malaria after treatment with chloroquine and adjuvant interferon-gamma.

The antibody response of mice infected with Plasmodium vinckei after treatment with chloroquine either alone or in combination with interferon-gamma (IFN-gamma) was determined. Sequential serum samples were drawn from BALB/c mice receiving either 240 micrograms chloroquine on the day of infection or 120 micrograms chloroquine plus 10(4) units IFN-gamma daily for 11 days beginning on day 3 prior to infection. Mice treated with additional IFN-gamma showed an early induction of IgG2a response and a reduction in IgG1 antibodies as detected by the immunofluorescence technique at between 10 and 16 days after infection as compared with mice treated with chloroquine alone. Thus, IFN-gamma may partly exert its antimalarial activity via the induction of IgG2a antibody formation. At 4-6 weeks after infection, when mice from both groups resisted homologous re-infection, the predominant antibody isotypes found in both groups were IgG1 and IgG2a. Serum samples obtained from mice in both treatment groups at 6 weeks after infection were used for serum transfer experiments. When parasitised erythrocytes were preincubated with such immune serum, a retardation of the course of parasitaemia by 2 days was observed.


Efficacy of intraruminal albendazole boluses against Dicrocoelium dendriticum in sheep.

The anthelmintic potential of albendazole (ABZ) in intraruminal boluses (Proftril-Captec) was investigated in sheep harbouring naturally acquired Dicrocoelium infection. The anthelmintic efficacy was assessed by coprological testing during the autumn pasture and comparison of worm counts in 22 necropsied animals (11 treated and 11 untreated) at the end of the experiment. The mean faecal egg count (EPG) in treated animals dropped significantly during week 2, and between the 4th and the 12th week the faecal samples were almost negative. The health status of treated animals improved significantly during the first 2 weeks. Helminthological dissection of livers and small intestines revealed 91.8% efficacy, but a small number of live adult flukes were found in all treated animals.


Antigen-induced protection against infection with Toxocara vitulorum larvae in mice.

Larvae of Toxocara vitulorum hatched and migrated in the tissues of normal mice. Larvae survived in reasonable numbers, particularly in the liver and, to a lesser extent, in the lungs and kidneys, for at least 4-7 days and in muscles, albeit only in low numbers, for at least 3 weeks. Oral infection of mice on three or more occasions with T. vitulorum eggs induced protection against a challenge infection with eggs of T. vitulorum. Prior parenteral immunization of mice with a variety of T. vitulorum soluble antigens (extracts, excretions/secretions, or perienteric fluid and their fractions) from adult parasites and/or infective larvae induced statistically significant protection against infection. The most effective protective immunogens were three or more injections with perienteric fluid from adults (100% protection) and excretions/secretions from infective larvae of T. vitulorum (> 92% protection).


Experimental chemotherapy of Schistosoma mansoni with praziquantel and oxamniquine: differential effect of single or combined formulations of drugs on various strains and on both sexes of the parasite.

The susceptibility of two Venezuelan (YT and SM) and one Brazilian (BH) strain of Schistosoma mansoni to single oral doses of praziquantel (Pz; 250 or 500 mg/kg), oxamniquine (Ox; 40, 60, or 100 mg/kg) or to low-dose combinations of both drugs (33 mg/kg Pz and 25 mg/kg Ox; 66 mg/kg Pz and 12.5 mg/kg Ox; 250 mg/kg Pz and 40 mg/kg Ox) was experimentally evaluated in mice. At lower doses of either drug, adult worms of the SM isolate were less susceptible than those of the BH and YT isolates. However, no difference in liver or intestinal egg counts (IECs) could be detected among the isolates after this treatment. At such doses, Pz was better than Ox at reducing IECs. In spite of lowered IECs, eggs continued to accumulate in the liver after Ox treatment. At higher individual doses or following treatment with low-dose combinations of both drugs, no difference in susceptibility could be detected among the parasite isolates. Under such conditions, oviposition was drastically reduced in all three isolates. We confirm that Ox preferentially kills male parasites and present for the first time evidence for the preferential killing of female worms by Pz. We propose that the synergistic effect obtained in the present study and in other investigations using low-dose combinations of both drugs may be due to the preferential cytotoxicity of each drug against a different parasite sex.


[Interrelationships between prolactin and the renin-aldosterone system in patients with various endocrine diseases].

Prolactin and aldosterone secretion and renin activity in the plasma were measured in the course of thyroliberin (TRH) test in women with various endocrine diseases, both connected with the water-salt metabolism disturbances and without these--with the idiopathic edemas (n = 11), hypothyrosis (n = 16), Stein-Leventhal'syndrome (n = 6), and obesity (n = 8). A reciprocal relationship between prolactin concentrations (a drastic elevation) and aldosterone levels (lowered) were revealed, as were universal responses of both the hormones to TRH administration in patients with various conditions. The authors come to a conclusion on the absence of a stimulating effect of prolactin on aldosterone secretion and plasma renin activity. They suggest an indirect contribution of prolactin to the regulation of the renin-aldosterone system, probably via dopaminergic mechanisms.


[The amygdaloid complex in the sexual differentiation of the brain].

Presents the results of many-year research of the systemic and structural functional arrangement of the amygdaloid complex of the rat brain as the neuroendocrine center involved in the regulation of the reproductive processes. Special attention was paid to the sexual dependence of the structural and functional arrangement of this section of the brain. The amygdaloid complex was found involved in the critical period of brain development in the processes of sexual differentiation, this fact resulting in sexual dimorphism, that manifests in sexual differences of this complex structural and functional arrangement and its histophysiology. Sexual dimorphism areas in each of the neuronal ensembles of the rat amygdaloid complexes singled out by the authors, are described.


Neuropeptide F-immunoreactivity in the monogenean parasite Diclidophora merlangi.

The localisation and distribution of neuropeptide F (NPF)-immunoreactivity (IR) in the monogenean fish-gill parasite, Diclidophora merlangi, have been investigated by whole-mount immunocytochemistry interfaced with confocal scanning laser microscopy and, at the ultrastructural level, by indirect immunogold labeling. Using antisera directed to intact synthetic NPF (Moniezia expansa, residues 1-39) or to the C-terminal decapeptide (residues 30-39) of synthetic NPF (M. expansa), immunostaining was found throughout the central (CNS) and peripheral nervous systems (PNS), including the innervation of the reproductive system. Immunoreactivity was found to be more intense using the antiserum to the C-terminal decapeptide fragment of NPF. At the subcellular level, gold labeling of NPF-IR was found exclusively over the contents of dense-cored vesicles that occupied nerve axons of both the CNS and the PNS. The distribution pattern of immunostaining for NPF mirrored exactly that previously documented for the vertebrate pancreatic polypeptide (PP) family of peptides and for FMRFamide. This finding and the results of preabsorption experiments strongly suggest that NPF is the predominant native neuropeptide in D. merlangi and that it accounts for most of the immunostaining previously obtained with PP and FMRFamide antisera.


[Late results of pancreatic blood outflow deportalization and its significance in the combined modality treatment of diabetes mellitus].

Present-day methods of treatment of insulin-dependent diabetes mellitus (IDD) fail to prevent the development of complications in the majority of patients in 5-10 years after the disease manifestation. There are no radical methods for the treatment of this condition, therefore any new treatment modality that may help delay the development of complications and deterioration of the quality of life should be used along with the traditional methods. Deportalization of the pancreatic blood outflow was carried out in 148 IDD patients and its remote (up to 5 years) results analyzed. The surgery was carried out in patients with medium-severe and grave conditions. Under study were carbohydrate and lipid metabolism, liver, kidney, and heart functions, retinal vessel status, and painful manifestations of distal polyneuropathy, as well as changes of the quantity of functioning capillaries and the rheovasographic index. Surgery resulted in reduced insulin requirement, disappearance of hypoglycemic comas, reduced peripheral resistance of the vessels, increased cardiac output index and a higher working capacity of the patients, disappearance of paroxysms and pains in the lower limbs, etc. The authors suppose that changed course of the disease is connected with recovery of the insulin-glucagon coefficient in the liver in glucagon-containing blood shunting into the total blood stream and with the pharmacologic effect of glucagon getting into the systemic blood stream.


The relationship of variable antigen expression and population growth rates in Trypanosoma brucei.

The relationship between variable antigen type (VAT) expression and trypanosome growth rates was investigated. Growth rates in mice were compared between pairs of cloned trypanosome populations, each of which homogeneously expressed a different VAT. All three pairwise combinations of GUTats (Glasgow University Trypanozoon antigen types) 7.3, 7.4 and 7.5 were analysed twice and all three combinations of GUTats 8.2, 8.3 and 8.4 were compared once. The lines expressing different VATs were of the same passage history within each group. In a sensitive assay of relative growth, no significant differences were found in four of six experiments using GUTats 7.3, 7.4 and 7.5 or in one of three experiments using GUTats 8.2, 8.3 and 8.4. In the experiments in which differences were observed, the data were analysed further to compare the population doubling times of lines. These times differed by less than 10% in all cases. We conclude that variable antigen expression exerts a small (possibly negligible) effect on rates of trypanosome population growth.


[Effect of changes in erythrocyte lipid spectrum on erythrocyte functional parameters in patients with diabetes mellitus].

Studies of the red cell lipid spectrum in diabetics and of the effects of bioactive substances and reconstruction of the red cell membrane lipid component on these cells aggregation have shown increased levels of lysophosphatidylcholine, cholesterol, cholesterol to phospholipid ratio, and saturated fatty acids in the presence of phosphatidylcholine reduction. Fluctuations in the levels of lipids of other classes were also revealed. Studies of red cell aggregation have revealed that incubation of donors' and diabetics' red cells with hormones did not lead to essential changes in the aggregation induced by alcian blue. Addition of an aliquot of plasma enriched for platelets, glycolipids and alpha-tocopherol resulted in a marked reduction of the aggregation degree and size of the aggregate. Phosphatidylcholine, phosphatidylinositol, and cholesterol-enriched liposome reconstruction of the red cell lipid composition also resulted in reduction of the aggregation degree and of the size of the red cell aggregate. This has brought the authors to a conclusion on a close relationship between the red cell lipid composition and the aggregation capacity in diabetics and on the possibility of regulating the red cell aggregation activity with bioactive substances.


Metabolites of alveolar Echinococcus as determined by [31P]- and [1H]-nuclear magnetic resonance spectroscopy.

[31P]-Nuclear magnetic resonance (NMR) in vivo spectra of Echinococcus multilocularis cysts growing subcutaneously in Meriones unguiculatus showed prominent signals due to phosphomonoesters (PME), phosphodiesters (PDE), inorganic phosphate (Pi) and the alpha, beta and gamma phosphate groups of adenosine triphosphate (ATP). The internal pH of the parasite cysts was 6.7-6.8. The 31P spectra of extracts of these subcutaneous cysts showed peaks identified as glucose-6-phosphate (Glu-6-P), glycerol-3-phosphate (Gly-3-P), phosphorylethanolamine (PE), adenosine-5'-monophosphate (5'-AMP), nicotinamide adenine dinucleotide phosphate (NADP), phosphorylcholine (PC), Pi, glycerolphosphorylethanolamine (GPE), glycerolphosphorylcholine (GPC), phosphoenolpyruvate (PEP), adenosine diphosphate (ADP), ATP and diphosphodiesters (DPDE). These metabolites were also detected at comparable concentrations in the extracts of intraperitoneally grown cysts. In addition, significantly more phosphocreatine (PCr), probably of host origin, was detected in the subcutaneous cysts than in the intraperitoneal cysts. [1H]-NMR spectra of cyst extracts revealed that parasites grown in the abdominal cavity contained significantly less glucose but significantly more succinate, acetate, alanine and beta-hydroxybutyrate. Glycogen, creatine, glycine, taurine, betaine, cholines and lactate were present at similar concentrations in cyst material from both locations.


Identification of circulating parasite acetylcholinesterase in human and rodent filariasis.

In the present study, the enzyme acetylcholinesterase (AChE) from filarial parasites was identified in sera from humans infected with Onchocerca volvulus as well as in Mastomys natalensis infected with Brugia pahangi. The enzyme was present in immune complexes precipitated with cold 4% polyethylene glycol. The infected sera showed 3-4 times more AChE activity than did normal sera, and enzyme activity could be demonstrated in 5% polyacrylamide gels by specific staining. The enzyme from infected serum showed 3 times more activity when acetylthiocholine was used as the substrate as compared with butyrylthiocholine, whereas the enzyme activity present in normal serum was low and did not show this substrate specificity. Immunoprecipitation assays confirmed the presence of anti-AChE antibodies in the infected serum. The enzyme was further analysed by enzyme-linked immunosorbent assay and immunoblotting with rabbit antibodies to B. malayi AChE. Immunoblotting of the B. pahangi-infected serum revealed two closely located bands at about 200 kDa and one 95-kDa band, whereas in O. volvulus-infected serum, only one specific band was observed at about 200 kDa. The identification of parasite AChE may be particularly useful for diagnosis of the disease or for the study of the involvement of this enzyme in the host-parasite relationship.


Ultrastructure of the development of a species of Encephalitozoon cultured from the eye of an AIDS patient.

Human fibroblast cell cultures inoculated with microsporidia-infected corneal scrapings from an AIDS patient were fixed in situ and examined by scanning and transmission electron microscopy. The parasite grew prolifically and all developmental stages were observed. Meronts underwent binary fission and the daughter cells transformed into elongate, chain-like sporonts that eventually separated into sporoblasts. The formation of components of the mature spores is described. The parasite, a species of Encephalitozoon, underwent development both in the cytoplasm and within a parasitophorous vacuole, distinguishing it from the morphologically similar species E. cuniculi and E. hellem, both of which have been described from lesions in the human eye and have been reported to develop exclusively within a parasitophorous vacuole.