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1.
Lupus ; 26(7): 773-776, 2017 Jun.
Article in English | MEDLINE | ID: mdl-27687020

ABSTRACT

Systemic lupus erythematosus (SLE), a disorder of the immune system, is potentially curable by allogeneic bone marrow transplantation (alloBMT). Until recently, alloBMT was limited by donor availability and toxicity. Reduced intensity conditioning (RIC) combined with post-transplantation cyclophosphamide (PTCy) has improved the availability and safety of alloBMT permitting its exploration in severe-refractory autoimmune illnesses. We report the six-year follow-up of a young female whose refractory SLE-associated nephrosis resolved after RIC alloBMT with PTCy.


Subject(s)
Bone Marrow Transplantation/methods , Cyclophosphamide/administration & dosage , Lupus Erythematosus, Systemic/therapy , Transplantation Conditioning/methods , Adult , Bone Marrow Transplantation/adverse effects , Female , Follow-Up Studies , Humans , Immunosuppressive Agents/administration & dosage , Lupus Erythematosus, Systemic/physiopathology , Transplantation, Homologous , Treatment Outcome
2.
Pediatr Crit Care Med ; 16(4): 366-74, 2015 May.
Article in English | MEDLINE | ID: mdl-25599148

ABSTRACT

OBJECTIVE: To determine the effect of therapeutic plasma exchange on hemodynamics, organ failure, and survival in children with multiple organ dysfunction syndrome due to sepsis requiring extracorporeal life support. DESIGN: A retrospective analysis. SETTING: A PICU in an academic children's hospital. PATIENTS: Fourteen consecutive children with sepsis and multiple organ dysfunction syndrome who received therapeutic plasma exchange while on extracorporeal life support from 2005 to 2013. INTERVENTIONS: Median of three cycles of therapeutic plasma exchange with median of 1.0 times the estimated plasma volume per exchange. MEASUREMENTS AND MAIN RESULTS: Organ Failure Index and Vasoactive-Inotropic Score were measured before and after therapeutic plasma exchange use. PICU survival in our cohort was 71.4%. Organ Failure Index decreased in patients following therapeutic plasma exchange (mean ± SD: pre, 4.1 ± 0.7 vs post, 2.9 ± 0.9; p = 0.0004). Patients showed improved Vasoactive-Inotropic Score following therapeutic plasma exchange (median [25th-75th]: pre, 24.5 [13.0-69.8] vs post, 5.0 [1.5-7.0]; p = 0.0002). Among all patients, the change in Organ Failure Index was greater for early therapeutic plasma exchange use than late use (early, -1.7 ± 1.2 vs late, -0.9 ± 0.6; p = 0.14), similar to the change in Vasoactive-Inotropic Score (early, -67.5 [28.0-171.2] vs late, -12.0 [7.2-18.5]; p = 0.02). Among survivors, the change in Organ Failure Index was greater among early therapeutic plasma exchange use than late use (early, -2.3 ± 1.0 vs late, -0.8 ± 0.8; p = 0.03), as was the change in Vasoactive-Inotropic Score (early, -42.0 [16.0-76.3] vs late, -12.0 [5.3-29.0]; p = 0.17). The mean duration of extracorporeal life support after therapeutic plasma exchange according to timing of therapeutic plasma exchange was not statistically different among all patients or among survivors. CONCLUSIONS: The use of therapeutic plasma exchange in children on extracorporeal life support with sepsis-induced multiple organ dysfunction syndrome is associated with organ failure recovery and improved hemodynamic status. Initiating therapeutic plasma exchange early in the hospital course was associated with greater improvement in organ dysfunction and decreased requirement for vasoactive and/or inotropic agents.


Subject(s)
Hemodynamics , Life Support Systems/statistics & numerical data , Multiple Organ Failure/therapy , Plasma Exchange/statistics & numerical data , Sepsis/complications , Adolescent , Child , Child, Preschool , Combined Modality Therapy/methods , Female , Humans , Infant , Length of Stay/statistics & numerical data , Male , Multiple Organ Failure/etiology , Multiple Organ Failure/physiopathology , Retrospective Studies , Severity of Illness Index , Survival Rate , Treatment Outcome
3.
ESMO Open ; 7(4): 100520, 2022 08.
Article in English | MEDLINE | ID: mdl-35753087

ABSTRACT

BACKGROUND: Ripretinib, a broad-spectrum KIT and platelet-derived growth factor receptor A switch-control tyrosine kinase inhibitor, is approved for the treatment of adult patients with advanced gastrointestinal stromal tumor as ≥ fourth-line therapy. We present the efficacy and safety of ripretinib in patients with KIT-altered metastatic melanoma enrolled in the expansion phase of the ripretinib phase I study. PATIENTS AND METHODS: Patients with KIT-altered metastatic melanoma were enrolled and treated with ripretinib at the recommended phase II dose of 150 mg once daily in 28-day cycles. Investigator-assessed responses according to Response Evaluation Criteria In Solid Tumors version 1.1 were carried out on day 1 of cycles 3, 5, 7, every three cycles thereafter, and at a final study visit. RESULTS: A total of 26 patients with KIT-altered metastatic melanoma (25 with KIT mutations, 1 with KIT-amplification) were enrolled. Patients had received prior immunotherapy (n = 23, 88%) and KIT inhibitor therapy (n = 9, 35%). Confirmed objective response rate (ORR) was 23% [95% confidence interval (CI) 9%-44%; one complete and five partial responses] with a median duration of response of 9.1 months (range, 6.9-31.3 months). Median progression-free survival (mPFS) was 7.3 months (95% CI 1.9-13.6 months). Patients without prior KIT inhibitor therapy had a higher ORR and longer mPFS (n = 17, ORR 29%, mPFS 10.2 months) than those who had received prior KIT inhibitor treatment (n = 9, ORR 11%, mPFS 2.9 months). The most common treatment-related treatment-emergent adverse events (TEAEs) of any grade in ≥15% of patients were increased lipase, alopecia, actinic keratosis, myalgia, arthralgia, decreased appetite, fatigue, hyperkeratosis, nausea, and palmar-plantar erythrodysesthesia syndrome. There were no grade ≥4 treatment-related TEAEs. CONCLUSIONS: In this phase I study, ripretinib demonstrated encouraging efficacy and a well-tolerated safety profile in patients with KIT-altered metastatic melanoma, suggesting ripretinib may have a clinically meaningful role in treating these patients.


Subject(s)
Melanoma , Naphthyridines , Urea , Adult , Gastrointestinal Stromal Tumors , Humans , Melanoma/drug therapy , Naphthyridines/adverse effects , Protein Kinase Inhibitors , Urea/adverse effects , Urea/analogs & derivatives
4.
J Evol Biol ; 24(4): 904-13, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21306463

ABSTRACT

In cooperatively breeding species, the fitness consequences of producing sons or daughters depend upon the fitness impacts of positive (repayment hypothesis) and negative (local competition hypothesis) social interactions among relatives. In this study, we examine brood sex allocation in relation to the predictions of both the repayment and the local competition hypotheses in the cooperatively breeding long-tailed tit Aegithalos caudatus. At the population level, we found that annual brood sex ratio was negatively related to the number of male survivors across years, as predicted by the local competition hypothesis. At an individual level, in contrast to predictions of the repayment hypothesis, there was no evidence for facultative control of brood sex ratio. However, immigrant females produced a greater proportion of sons than resident females, a result consistent with both hypotheses. We conclude that female long-tailed tits make adaptive decisions about brood sex allocation.


Subject(s)
Passeriformes/physiology , Sex Ratio , Animals , Female , Male
5.
Proc Biol Sci ; 276(1660): 1215-23, 2009 Apr 07.
Article in English | MEDLINE | ID: mdl-19141421

ABSTRACT

The migratory movements of seabirds (especially smaller species) remain poorly understood, despite their role as harvesters of marine ecosystems on a global scale and their potential as indicators of ocean health. Here we report a successful attempt, using miniature archival light loggers (geolocators), to elucidate the migratory behaviour of the Manx shearwater Puffinus puffinus, a small (400 g) Northern Hemisphere breeding procellariform that undertakes a trans-equatorial, trans-Atlantic migration. We provide details of over-wintering areas, of previously unobserved marine stopover behaviour, and the long-distance movements of females during their pre-laying exodus. Using salt-water immersion data from a subset of loggers, we introduce a method of behaviour classification based on Bayesian machine learning techniques. We used both supervised and unsupervised machine learning to classify each bird's daily activity based on simple properties of the immersion data. We show that robust activity states emerge, characteristic of summer feeding, winter feeding and active migration. These can be used to classify probable behaviour throughout the annual cycle, highlighting the likely functional significance of stopovers as refuelling stages.


Subject(s)
Animal Migration/physiology , Artificial Intelligence , Birds/physiology , Animals , Bayes Theorem , Female , Oceans and Seas , Telemetry
6.
J Cell Biol ; 96(6): 1592-600, 1983 Jun.
Article in English | MEDLINE | ID: mdl-6343401

ABSTRACT

Two mutants of Saccharomyces cerevisiae have been isolated from normal haploid MAT alpha strains and characterized as having temperature-sensitive, pleiotropic phenotypes for functions associated with mating. At the permissive temperature, 23 degrees C, they were found to behave as normal MAT alpha haploids with respect to mating efficiency, sporulation in diploids formed with MAT a strains, secretion of alpha-factor, and failure to secrete the MATa-specific products, a-factor and Barrier. At higher temperatures they were found to decline in mating and sporulation efficiency and to express the a-specific functions. Genetic analysis established that one of these mutants, PE34, carries a temperature-sensitive allele of the MAT alpha 2 gene and that the other, PD7, carries a temperature-sensitive allele of the TUP1 gene.


Subject(s)
Mutation , Saccharomyces cerevisiae/genetics , Temperature , Alleles , Phenotype , Reproduction , Saccharomyces cerevisiae/physiology
7.
J Cell Biol ; 120(2): 385-98, 1993 Jan.
Article in English | MEDLINE | ID: mdl-8421054

ABSTRACT

We report the nucleotide and derived amino acid sequence of the ATPase 1 gene from Plasmodium falciparum. The amino acid sequence shares homology with the family of "P"-type cation translocating ATPases in conserved regions important for nucleotide binding, conformational change, or phosphorylation. The gene, which is present on chromosome 5, has a product longer than any other reported for a P-type ATPase. Interstrain analysis from 12 parasite isolates by the polymerase chain reaction reveals that a 330-bp nucleotide sequence encoding three cytoplasmic regions conserved in cation ATPases (regions a-c) is of constant length. By contrast, another 360-bp sequence which is one of four regions we refer to as "inserts" contains arrays of tandem repeats which show length variation between different parasite isolates. Polymorphism results from differences in the number and types of repeat motif contained in this insert. Inserts are divergent in sequence from other P-type ATPases and share features in common with many malarial antigens. Studies using RNA from the erythrocytic stages of the malarial life cycle suggest that ATPase 1 (including the sequence which encodes tandem repeats) is expressed at the large ring stage of development. Immunolocalization has identified ATPase 1 to be in the region of the parasite plasma membrane and pigment body. These findings suggest a possible model for the genesis of malarial antigens.


Subject(s)
Multigene Family , Plasmodium falciparum/enzymology , Plasmodium falciparum/genetics , Proton-Translocating ATPases/genetics , Adenosine Triphosphatases/genetics , Amino Acid Sequence , Animals , Base Sequence , Blotting, Southern , Chromosome Mapping , Cloning, Molecular , DNA, Protozoan/genetics , DNA, Protozoan/isolation & purification , Molecular Sequence Data , Oligodeoxyribonucleotides , Polymerase Chain Reaction/methods , Polymorphism, Genetic , Rats , Restriction Mapping , Sequence Homology, Amino Acid
8.
Science ; 229(4718): 1099-101, 1985 Sep 13.
Article in English | MEDLINE | ID: mdl-4035350

ABSTRACT

Amastigotes (tissue forms) of Leishmania donovani isolated from infected hamster spleens carried out several physiological activities (respiration, catabolism of energy substrates, and incorporation of precursors into macromolecules) optimally at pH 4.0 to 5.5. All metabolic activities that were examined decreased sharply above the optimal pH. Promastigotes (culture forms), on the other hand, carried out the same metabolic activities optimally at or near neutral pH. This adaptation to an acid environment may account in part for the unusual ability of amastigotes to survive and multiply within the acidic environment of the phagolysosomes in vivo.


Subject(s)
Hydrogen-Ion Concentration , Leishmania/metabolism , Animals , Cricetinae , Glucose/metabolism , Leishmania/growth & development , Nucleosides/metabolism , Oxygen Consumption , Proline/metabolism , Spleen/parasitology
9.
Science ; 228(4695): 21-6, 1985 Apr 05.
Article in English | MEDLINE | ID: mdl-17811549

ABSTRACT

A strain of Saccharomyces cerevisiae capable of simultaneous hydrolysis and fermentation of highly polymerized starch oligosaccharides was constructed. The Aspergillus awamori glucoamylase enzyme, form GAI, was expressed in Saccharomyces cerevisiae by means of the promoter and termination regions from a yeast enolase gene. Yeast transformed with plasmids containing an intron-free recombinant glucoamylase gene efficiently secreted glucoamylase into the medium, permitting growth of the transformants on starch as the sole carbon source. The natural leader sequence of the precursor of glucoamylase (preglucoamylase) was processed correctly by yeast, and the secreted enzyme was glycosylated through both N- and O-linkages at levels comparable to the native Aspergillus enzyme. The data provide evidence for the utility of yeast as an organism for the production, glycosylation, and secretion of heterologous proteins.

10.
Appl Environ Microbiol ; 74(19): 5913-7, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18641152

ABSTRACT

The microbial contamination of air filters and possible links to contaminated product in a powdered milk protein-processing facility were investigated. Over a 10-month period, seven air filters, the environment, and powdered product were analyzed for the presence of Cronobacter spp. The effects of air filter installation, maintenance, and subsequent dissemination of Cronobacter were investigated. A total of 30 isolates were characterized by pulsed-field gel electrophoresis (PFGE). PFGE revealed the presence of three clonal populations distributed throughout the manufacturing site. This study highlights the need for proper installation of air filters to limit the dissemination of microorganisms into processing sites.


Subject(s)
Cronobacter sakazakii/classification , Cronobacter sakazakii/isolation & purification , Environmental Microbiology , Food Contamination , Food Microbiology , Bacterial Typing Techniques , Cluster Analysis , Cronobacter sakazakii/genetics , DNA Fingerprinting , DNA, Bacterial/genetics , Electrophoresis, Gel, Pulsed-Field , Genotype , Milk Proteins
11.
Eur J Pain ; 2018 Apr 10.
Article in English | MEDLINE | ID: mdl-29633429

ABSTRACT

BACKGROUND: Preclinical assays of affective and sensorial aspects of nociception play a key role in research on both the neurobiology of pain and the development of novel analgesics. Therefore, we investigated the effects of nicotine and alpha-7 nicotinic acetylcholine receptor (nAChR) modulators in the negative affective and sensory components of visceral pain in mice. METHODS AND RESULTS: Intraperitoneal acetic acid (AA) administration resulted in a robust stretching behaviour and conditioned place aversion (CPA) in mice. We observed a dose-dependent reduction in AA-induced stretching and CPA by the nonselective nAChRs agonist nicotine. Mecamylamine, a nonselective nAChRs agonist, was able to block its effects; however, hexamethonium, a peripherally restricted nonselective nicotinic antagonist, was able to block nicotine's effect on stretching behaviour but not on CPA. In addition, systemic administration of α7 nAChR full agonists PHA543613 and PNU282987 was failed to block stretching and CPA behaviour induced by AA. However, the α7 nAChR-positive allosteric modulator PNU120596 blocked AA-induced CPA in a dose-dependent manner without reducing stretching behaviours. CONCLUSIONS: Our data revealed that while nonselective nAChR activation induces antinociceptive properties on the sensorial and affective signs of visceral pain in mice, α7 nAChRS activation has no effect on these responses. In addition, nonselective nAChR activation-induced antinociceptive effect on stretching behaviour was mediated by central and peripheral mechanisms. However, the effect of nonselective nAChR activation on CPA was mediated centrally. Furthermore, our data suggest a pivotal role of allosteric modulation of α7 nAChRS in the negative affective, but not sensory, component of visceral pain. SIGNIFICANCE: The present results suggest that allosteric modulation of α7 nAChR may provide new strategies in affective aspects of nociception.

12.
J Clin Invest ; 51(7): 1805-12, 1972 Jul.
Article in English | MEDLINE | ID: mdl-4624352

ABSTRACT

The Lesch-Nyhan syndrome is characterized clinically by choreoathetosis, spasticity, selfmutilation, and mental and growth retardation. Biochemically, there is a striking reduction of hypoxanthine-guanine phosphoribosyltransferase (HGPRT) activity in affected individuals. We have examined erythrocytes from 14 patients with the Lesch-Nyhan syndrome for the presence of hypoxanthine-guanine phosphoribosyltransferase activity and enzyme protein. In contrast to the usual finding of no detectable hypoxanthine-guanine phosphoribosyltransferase activity, we have found low levels (0.002-0.79 nmoles/mg protein per hr) of hypoxanthine-guanine phosphoribosyltransferase activity in erythrocyte lysates from five of these patients. In three of the five patients, hypoxanthine-guanine phosphoribosyltransferase activity appeared to be substantially more labile in vivo than normal using erythrocytes which had been separated according to their density (age). Immunochemical studies using a monospecific antiserum prepared from a homogeneous preparation of normal human erythrocyte hypoxanthine-guanine phosphoribosyltransferase revealed immunoreactive protein (CRM) in hemolysate from all 14 patients with the Lesch-Nyhan syndrome. The immunoreactive protein from each patient gave a reaction of complete identity with normal erythrocyte hypoxanthine-guanine phosphoribosyltransferase and was present in quantities equal to those observed in normal erythrocytes. In addition, a constant amount of CRM was found in erythrocytes of increasing density (age) from patients with the Lesch-Nyhan syndrome despite the decreasing hypoxanthine-guanine phosphoribosyltransferase activity. These studies confirm previous data which indicate that the mutations leading to the Lesch-Nyhan syndrome are usually, if not always on the structural gene coding for hypoxanthine-guanine phosphoribosyltransferase. In addition, although the mutant proteins appear to be present in normal amounts, they are often very labile in vivo with respect to enzymatic activity. These observations suggest that therapy directed at stabilization or activation of enzyme activity in vivo may be of potential benefit.


Subject(s)
Purine-Pyrimidine Metabolism, Inborn Errors/enzymology , Transferases/blood , Athetosis , Carbon Isotopes , Erythrocytes/enzymology , Guanine , Humans , Hypoxanthines , Immunodiffusion , Immunoelectrophoresis , Intellectual Disability , Lesch-Nyhan Syndrome/blood , Lesch-Nyhan Syndrome/enzymology , Mutation , Self Mutilation
13.
Mol Cell Biol ; 7(11): 3937-46, 1987 Nov.
Article in English | MEDLINE | ID: mdl-2828921

ABSTRACT

An oligonucleotide probe was used to clone a cation-transporting ATPase gene from the genome of Leishmania donovani. The nucleotide sequence of the gene contained a 2,922-base-pair open reading frame that was predicted to encode a 107,406-dalton protein composed of 974 amino acids. The predicted L. donovani protein contained all the structural and functional domains expected to be present in a cation-transporting ATPase of the aspartyl phosphate class. The nucleotide sequence encoding the ATPase gene was duplicated in tandem in the parasite genome. Partial sequenation of the second member of the tandem repeat, which lay 2 kilobase pairs downstream of the ATPase gene, indicated that it was either identical to the first gene or very closely related to it. RNA homologous to either the ATPase gene or its adjacent relative was 5 kilobases in size and was approximately equally abundant in both promastigote and amastigote forms of the organism.


Subject(s)
Adenosine Triphosphatases/genetics , Genes , Leishmania donovani/genetics , Transcription, Genetic , Amino Acid Sequence , Animals , Base Sequence , Cloning, Molecular , DNA Restriction Enzymes , Leishmania donovani/enzymology , Molecular Sequence Data , Nucleotide Mapping , Sequence Homology, Nucleic Acid
14.
Mol Cell Biol ; 5(10): 2613-22, 1985 Oct.
Article in English | MEDLINE | ID: mdl-3016511

ABSTRACT

Cultured rat cells deficient in endogenous thymidine kinase activity (tk) were stably transformed with a recombination-indicator DNA substrate constructed in vitro by rearrangement of the herpes simplex virus tk gene sequences into a partially redundant permutation of the functional gene. The recombination-indicator DNA did not express tk, but was designed to allow formation of a functional tk gene via homologous recombination. A clonal cell line (519) was isolated that harbored several permuted herpes simplex virus tk genes. 519 cells spontaneously produced progeny that survived in medium containing hypoxanthine, aminopterin, and thymidine. Acquisition of resistance to hypoxanthine, aminopterin, and thymidine was accompanied by the rearrangement of the defective tk gene to functional configuration. The rearrangement apparently occurred by unequal exchange between one permuted tk gene and a replicated copy of itself. Recombination was between 500-base-pair tracts of DNA sequence homology that were separated by 3.4 kilobases. Exchanges occurred spontaneously at a frequency of approximately 5 X 10(-6) events per cell per generation. Recombination also mediated reversion to the tk- phenotype; however, the predominant mechanism by which cells escaped death in the presence of drugs rendered toxic by thymidine kinase was not recombination, but rather inactivation of the intact tk gene.


Subject(s)
Recombination, Genetic , Animals , Cells, Cultured , Chromosome Deletion , Chromosome Mapping , DNA Restriction Enzymes , Genetic Linkage , Rats , Selection, Genetic , Sequence Homology, Nucleic Acid , Sister Chromatid Exchange , Thymidine Kinase/genetics
15.
Mol Cell Biol ; 4(11): 2306-15, 1984 Nov.
Article in English | MEDLINE | ID: mdl-6440004

ABSTRACT

The filamentous ascomycete Aspergillus awamori secretes large amounts of glucoamylase upon growth in medium containing starch, glucose, or a variety of hexose sugars and sugar polymers. We examined the mechanism of this carbon source-dependent regulation of glucoamylase accumulation and found a several hundredfold increase in glucoamylase mRNA in cells grown on an inducing substrate, starch, relative to cells grown on a noninducing substrate, xylose. We postulate that induction of glucoamylase synthesis is regulated transcriptionally. Comparing total mRNA from cells grown on starch and xylose, we were able to identify an inducible 2.3-kilobase mRNA-encoding glucoamylase. The glucoamylase mRNA was purified and used to identify a molecularly cloned 3.4-kilobase EcoRI fragment containing the A. awamori glucoamylase gene. Comparison of the nucleotide sequence of the 3.4-kilobase EcoRI fragment with that of the glucoamylase I mRNA (as determined from molecularly cloned cDNA) revealed the existence of four intervening sequences within the glucoamylase gene. The 5' end of the glucoamylase mRNA was mapped to several locations within a region -52 to -73 nucleotides from the translational start. Sequence and structural features of the glucoamylase gene of the filamentous ascomycete A. awamori were examined and compared with those reported in genes of other eucaryotes.


Subject(s)
Aspergillus/genetics , Genes, Fungal , Glucan 1,4-alpha-Glucosidase/genetics , Glucosidases/genetics , Base Sequence , Cloning, Molecular , Gene Expression Regulation , RNA, Fungal/genetics , RNA, Messenger/genetics
16.
HLA ; 89(2): 82-89, 2017 02.
Article in English | MEDLINE | ID: mdl-28102038

ABSTRACT

A limitation of solid-phase human leukocyte antigen (HLA) antibody assays is the falsely low/negative result of samples with high-titer antibodies, a phenomenon known as the prozone effect. Here we compared the efficacy of ethylenediaminetetraacetic acid (EDTA) and dithiothreitol (DTT) treatment of serum samples in overcoming the prozone effect. A total of 21 serum samples were treated with either EDTA or DTT before HLA single antigen bead assay. The efficacy of prozone effect reversal, compared with untreated samples, was examined on fourfold, serially diluted samples, from neat to 1:256, using PBS as diluent. EDTA reversed the prozone effect in all tested samples, with an efficiency of greater than 84%, estimated by the ratio of undiluted sample mean fluorescence intensity (MFI) to peak MFI, for any given dilution. In contrast, the efficiency of DTT treatment was as low as 47%. These results show superior prozone effect reversal with EDTA treatment, compared with DTT.


Subject(s)
Edetic Acid/chemistry , HLA Antigens/blood , Histocompatibility Testing/standards , Immunoassay/standards , Antibodies/chemistry , Dithiothreitol/chemistry , False Negative Reactions , HLA Antigens/classification , HLA Antigens/genetics , HLA Antigens/immunology , Histocompatibility Testing/methods , Humans , Immunoassay/methods
17.
Int J Parasitol ; 36(4): 381-93, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16442543

ABSTRACT

Leishmania donovani requires actively transporting proton efflux pumps to survive the acidic environment of macrophage phagolysosomal vacuoles and to maintain an electrogenic H(+) gradient for nutrient uptake. The L. donovani genome contains a differentially expressed pair of genes, LDH1A and LDH1B, with homology to yeast H(+)-ATPases that are 98% identical in sequence with amino acid differences concentrated at the COOH-terminus (15 of last 37 differ), a region implicated in regulation of yeast and plant proton pumps. Functional complementation of a Saccharomyces cerevisiae strain deficient in endogenous H(+)-ATPase activity, support of yeast growth at low pH, and ability to acidify media demonstrate that LDH1A and LDH1B encode proton pumps. LDH1A and LDH1B encode a COOH-terminal autoinhibitory domain as COOH-truncated peptides support increased rates of growth in yeast, enhanced media acidification, increased enzyme activity (V(max)) and decreased K(m). This regulatory domain mediates differing function properties; LDH1A, but not LDH1B, supports yeast growth at pH 3 and LDH1A shows a greater ability to acidify media. Deletion of the last eight amino acids from LDH1B permits growth at pH 3 and increases media acidification, swapping of the COOH-tails between LDH1A and LDH1B results in LDH1A (with LDH1B tail) unable to support yeast growth at pH 3 and LDH1B (with LDH1A tail) now able to support growth at pH 3. Replacement of the COOH-terminal eight amino acids of LDH1B with those from LDH1A also confers the ability to support growth at pH 3. The complementation system for the Leishmania proton pumps in yeast described here provides a means to dissect the functional properties of the two isoforms, a convenient supply of protein for structural analysis and a model amenable to screening proton pump inhibitors for potential anti-leishmanial therapeutics.


Subject(s)
Leishmania donovani/physiology , Proton-Translocating ATPases/genetics , Animals , Blotting, Northern , Blotting, Southern , Culture Media , Gene Expression Regulation/physiology , Genes, Protozoan , Genetic Complementation Test , Hydrogen-Ion Concentration , Leishmania donovani/enzymology , Leishmania donovani/genetics , Plasmids , Proton Pumps/genetics , Proton Pumps/physiology , Proton-Translocating ATPases/metabolism , Proton-Translocating ATPases/physiology , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/growth & development , Transformation, Genetic
18.
Cancer Res ; 48(13): 3801-7, 1988 Jul 01.
Article in English | MEDLINE | ID: mdl-3132320

ABSTRACT

Huggins and Morii (J. Exp. Med., 114: 741, 1961) reported that massive adrenal necrosis occurs in 79 and 100% of female Sprague-Dawley rats receiving 20 and 30 mg, respectively, of the mammary carcinogen 7,12-dimethylbenz(a)anthracene (DMBA). Here, adrenal necrosis and regeneration were studied in 158 rats for up to 21 days post-DMBA by radioautography of the adrenals of animals given 50 microCi [3H]thymidine 30 min before sacrifice. Adrenal cell proliferation was markedly inhibited 21 days post-DMBA. Regenerated adrenals were more susceptible to this adrenocorticolytic effect. To investigate if alterations in adrenal function modify tumorigenesis, animals underwent adrenalectomies (ADX), hypophysectomies, ovariectomies, and pituitary transplants alone or in combination 6 days after receiving DMBA (20 mg/100 g intragastrically) at 50 days of age. To prevent adrenal necrosis, 24 animals were pretreated with metyrapone. Methylprednisolone acetate, 1 mg i.m., was given to 40 animals every 5 days beginning 6 days post-DMBA. There were 50 non-DMBA-treated intact and surgical controls. DMBA was necessary but not sufficient to induce mammary tumors. No tumors developed in controls or in 46 animals hypophysectomized 6 days after DMBA. Metyrapone reduced tumor incidence and yield. ADX after DMBA treatment increased the tumorigenic response and eliminated resistance to tumorigenesis in older rats. Only three tumors developed in DMBA-treated rats receiving methylprednisolone acetate. Mammary tumorigenesis was increased by pituitary transplant 6 days after DMBA to intact and ADX animals. Ovariectomy 6 days after DMBA was as effective as methylprednisolone acetate in preventing tumorigenesis; ADX did not overcome either inhibition. We conclude that adrenal hormones inhibit proliferation of initiated mammary cells.


Subject(s)
Adrenal Glands/physiopathology , Mammary Neoplasms, Experimental/physiopathology , 9,10-Dimethyl-1,2-benzanthracene/toxicity , Adrenal Cortex Hormones/pharmacology , Adrenal Glands/pathology , Adrenalectomy , Age Factors , Animals , Cell Division/drug effects , Female , Hypophysectomy , Metyrapone/pharmacology , Necrosis , Ovariectomy , Prolactin/pharmacology , Rats , Time Factors
19.
Genetics ; 104(2): 235-40, 1983 Jun.
Article in English | MEDLINE | ID: mdl-6190703

ABSTRACT

Phenethyl alcohol inhibits the growth of many microorganisms. It is believed that the growth inhibition is mediated by its effect on the cell membrane. Differences between sensitive and resistant strains are suggested to be due to alterations in membrane structure. We report that, in some strains, an unexpected relationship exists between auxotrophy for tryptophan, tyrosine and phenylalanine and sensitivity to phenethyl alcohol.


Subject(s)
Ethanol/analogs & derivatives , Mutation , Phenylalanine/genetics , Phenylethyl Alcohol/toxicity , Saccharomyces cerevisiae/genetics , Tryptophan/genetics , Tyrosine/genetics , Saccharomyces cerevisiae/drug effects , Species Specificity
20.
Genetics ; 88(2): 235-8, 1978 Feb.
Article in English | MEDLINE | ID: mdl-17248796

ABSTRACT

Angehrn and Gutz (1968) have shown that homozygosity for the mat1-M allele in diploid strains of Schizosaccharomyces pombe increases mitotic recombination between his7 and mat2. In this paper, we report that meiotic recombination frequencies can vary from 3.4 to 16.1 percent between his7 and his2 and that this variation is due to the combination of alleles at the mat1 and mat2 loci.

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