Histophilus somni myocarditis in a beef rearing calf in the United Kingdom.
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Animals↗
Biomedical subjects
J Wessels
Publications and source records attributed to J Wessels.
Histophilus somni myocarditis in cattle in the UK.
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Animals↗
Quantitative molecular monitoring of residual tumor cells in chronic lymphocytic leukemia.
New therapeutic approaches for the treatment of B-cell chronic lymphocytic leukemia (B-CLL) can induce remarkable responses. Molecular remissions have been observed occasionally after high-dose chemotherapy. Thus, new improved techniques to monitor residual tumor cells on a molecular basis in CLL are warranted. For this purpose, a real-time quantitative allele-specific oligonucleotide polymerase chain reaction (ASO-PCR) for patients with B-CLL was designed. In the present study, the PCR assay was standardized with identical cycling parameters as well as primer, probe, and MgCl(2) concentration for each patient. Ten patients were monitored with DNA samples obtained at 52 time points (median: 5.2 per patient). The median follow-up per patient was 11.4 months. Nine of ten patients had PCR-detectable residual tumor cells in the peripheral blood after therapy. One patient became PCR negative with a combination of fludarabine and rituximab after the end of treatment. The MRD levels in patients with detectable disease ranged from 0.002% to 10.1% after therapy. We conclude that real-time quantitative ASO-PCR can be utilized for quantitative molecular monitoring of minimal residual disease (MRD) in B-CLL patients in complete remission (CR), that new effective treatment approaches such as combined chemo/immunotherapy can render CLL patients PCR negative, and that different MRD levels in PCR-positive patients were observed warranting further investigation into possible correlation with clinical outcome.
Aged↗
The expression of the RLF/INSL3 gene is reduced in Leydig cells of the aging rat testis.
The relaxin-like factor (RLF), which is the product of the INSL3 gene, is highly expressed in the fetal and adult-type Leydig cells of all species so far examined. In adult testes it is upregulated at puberty but appears subsequently to be expressed in a constitutive manner, independently of acute changes in the hypothalamic-pituitary-gonadal (HPG) axis. Functional hypogonadism with decreased testosterone is prevalent in the aging male. In order to test whether this is a property of the HPG axis, or of the Leydig cells themselves, RLF/INSL3 was used as an independent marker to assess rat Leydig cell differentiation status. Hybridization analysis showed that in the testes of old (2 years) rats, RLF/INSL3 mRNA expression was dramatically reduced, compared to young (3 months) animals. This was also evident at the protein level using immunohistochemistry. The results suggest that increasing functional hypogonadism in older male mammals is likely caused by a dedifferentiation of the Leydig cells themselves.
Aging↗
Cloning and expression analysis of testis-specific cyclic 3', 5'-adenosine monophosphate-responsive element modulator activators in the nonhuman primate (Macaca fascicularis): comparison with other primate and rodent species.
The cAMP-responsive element modulator (CREM) gene encodes a transcription factor that is essential for spermatogenesis. In mouse testis, several CREM repressors and activators have been identified. In contrast to the situation for the mouse, however, little is known about CREM isoforms in the primate testis. We analyzed CREM isoforms and mRNA expression in a clinically relevant primate model, the cynomolgus monkey (Macaca fascicularis). A cDNA library was generated from monkey testis; and two activator isoforms (tau2 with and without exon gamma) were identified, which displayed high sequence identity to mouse and human isoforms. The insertion of exon gamma was observed for the first time in the primate testis. CREM activator expression was confined to the testis, where it was seen in late pachytene spermatocytes and round spermatids in specific spermatogenic stages, as revealed by in situ hybridization. Comparison of the mRNA and the recently described protein expression indicated a lack of translational delay of CREM expression. Comparative analysis of testicular CREM expression by reverse transcription-polymerase chain reaction yielded several transcripts in the rat, mouse, hamster, and marmoset; two transcripts in cynomolgus and rhesus monkeys; and one transcript in men. These findings suggest an evolutionary trend from multiple activator isoforms to a single activator transcript in men.
Amino Acid Sequence↗
'Paracrine' control of spermatogenesis.
Spermatogenesis is a remarkably complex but precise process yielding highly differentiated haploid germ cells from diploid stem cells. Although many factors have been implicated in the paracrine control of spermatogenesis, functional proof is only available for a few regulators. Among those are androgens, growth factors and stem cell factor. Cell- and organ-specific genetargeting will provide important insights into the relevance of local factors controlling male gametogenesis. As testicular communication frequently occurs between rather remote cells and compartments, it is proposed that the term 'local' rather than 'paracrine' mediators/factors should be used, since the latter term refers to communication amongst neighbouring cells (and mainly via diffusion).
Animals↗
[Hemoptysis with intralobar pulmonary sequestration].
Pulmonary sequestration is a rare congenital malformation of the pulmonary parenchyma. A case of recurrent haemoptysis and pulmonary infections in an adult is presented. Arteriography was required to identify the aberrant vessel preoperatively. Thoracotomy confirmed an intralobar sequestration type. Anatomical classification, symptoms, and diagnostic approach are discussed. Symptomatic patients benefit from surgical resection.
Adult↗
Blue light-induced singlet oxygen generation by retinal lipofuscin in non-polar media.
Accumulation of lipofuscin (LF) is a prominent feature of aging in the human retinal pigment epithelium (RPE) cells. This age pigment exhibits substantial photoreactivity, which may increase the risk of retinal photodamage and contribute to age-related maculopathy. In a previous study, we detected singlet oxygen generation by lipofuscin granules excited with blue light. In this paper we investigated the ability of hydrophobic components of lipofuscin to photogenerate singlet oxygen in non-polar environments. Singlet oxygen was detected directly by monitoring its characteristic phosphorescence at ca 1270 nm. The action spectrum of singlet oxygen formation indicated that this process was strongly wavelength-dependent and its efficiency decreased with increasing wavelength by a factor of ten, comparing 420 nm and 520 nm. The quantum yield of singlet oxygen increased with increasing concentration of oxygen. Using laser flash photolysis we studied the possible mechanism of singlet oxygen formation. The observed transient, with a broad absorption spectrum peaking at around 440 nm, was identified as a triplet with lifetime ca 11 microseconds. It was quenched by both molecular oxygen and beta-carotene with concomitant formation of a beta-carotene triplet state. These results indicate the potential role of hydrophobic components of lipofuscin in blue light-induced damage to the RPE.
Aged↗
Expression of mitotic cyclin B1 is not confined to proliferating cells in the rat testis.
Spermatogenesis is a precisely controlled and timed process comprising mitotic divisions of spermatogonia, meiotic divisions of spermatocytes, and the maturation and differentiation of haploid spermatids. Cell proliferation is controlled by genes involved in the regulation of the cell cycle. Among the principal regulatory proteins are cyclins, which are categorized according to their appearance during the cell cycle. B-type cyclins are mitotic cyclins and function at the G2/M transition of the cell cycle. We have investigated the expression and regulation of cyclin B1 during rat spermatogenesis. Rat cyclin B1 was isolated from a testis cDNA library and further used as a probe to detect mRNA expression. Northern blot hybridization of testis mRNA revealed the presence of a single 1.7-kilobase transcript. In situ hybridization showed stage-specific expression during spermatogenesis with highest expression found in late pachytene spermatocytes and early round spermatids. This pattern was confirmed in fractions of isolated germ cells. Immunocytochemistry displayed highest protein levels in round spermatids. Depletion of gonadotropins did not change the quantitative and qualitative expression pattern of cyclin B1. Therefore, the signals triggering the onset of cyclin B1 expression seem not to originate from the pituitary-gonadal endocrine axis and might therefore be paracrine factors originating within the germinal epithelium. Our observations suggest that cyclin B1 plays a hitherto unknown role in spermatid maturation in addition to its known function in dividing cells.
Amino Acid Sequence↗
Nitric oxide synthase inhibition in a spontaneously hypertensive rat model of diabetic nephropathy.
1. To investigate the role of nitric oxide (NO) in diabetic nephropathy the effect of nitric oxide synthase (NOS) inhibition by NG-nitro-L-arginine methyl ester (L-NAME) was observed in a streptozotocin diabetic spontaneously hypertensive rat (SHR) model. 2. Two groups of SHR (n = 8) with streptozotocin-induced diabetes were studied. One group was given L-NAME 5 mg/kg bodyweight per day in the drinking water for 8 weeks while both groups received daily subcutaneous injections of Ultratard insulin. Creatinine clearance, urinary protein excretion, urinary nitrate concentration and systolic blood pressure were measured at fortnightly intervals. Rats were killed at 8 weeks and plasma angiotensin II (AngII) was measured by radioimmunoassay. 3. Renal function (endogenous creatinine clearance) remained stable in both groups. In the L-NAME group, however, there was a progressive increase in proteinuria that was highly significant at 6 weeks (22.1 +/- 2.9 compared with 6.5 +/- 0.7 mg/ 24 h per 100 g in control SHR diabetic rats P < 0.001). 4. Systolic blood pressure was significantly elevated in the L-NAME group throughout the study compared with the control group. 5. Plasma AngII was significantly elevated in the L-NAME group compared with controls (42.8 +/- 10.3 vs 15.1 +/- 1.9 pmol/L, respectively; P < 0.05). 6. Activation of the renin-angiotensin system may account, at least in part, for the resulting vasoconstrictor activity with chronic nitric oxide depletion.
Animals↗
Coordinate expression of splice variants of the murine pregnancy-specific glycoprotein (PSG) gene family during placental development.
The human and murine pregnancy-specific glycoprotein (PSG) gene families encode a large number of closely related proteins which are abundantly expressed in the fetal trophoblast and secreted into the maternal circulation. Although the presence of a well conserved tripeptide sequence His or Arg-Gly-Asp or Glu or Lys (H/RGD/E/K) similar to the RGD motif found in extracellular matrix proteins hints towards a possible interaction with integrin-type receptors, the function of this group of proteins related to the carcinoembryonic antigen family is still unknown. It is also not clear whether the various members of the PSG family exert the same function. Here we describe the cloning of two splice variants of Cea4 (Cea4a, Cea4b), a murine PSG family member, which lacks the RGD-related consensus motif. Cea4a, like most of the other rodent PSG members, is composed of three immunoglobulin (Ig) variable-like domains (N1-N3) and and one Ig constant-like domain (A). In contrast, Cea4b lacks the N2 domain (N1N3A), demonstrating for the first time that PSG isoforms produced by alternative splicing also exist in mice. The mRNAs coding for Cea4a and Cea4b exhibit the same expression kinetics during placental development as found for two other murine PSGs, Cea2 and Cea3, which contain the RGD-like motif. Expression starts after day 12.5 of embryonic development (E12.5) and maximum steady-state levels are reached around E15.5-E17.5 as determined by RNase protection analyses. At E17.5, PSG transcripts can be detected exclusively in the spongiotrophoblast of the placenta. In addition, PCR analyses revealed that Cea2, Cea3, and Cea4 transcripts are also found in RNA from a pool of embryos (E12-E15) but are absent from a number of adult tissues tested (kidney, lung, testis, ovary, liver, brain, thymus, heart, spleen). These results indicate that the various PSG isoforms exert their function(s) at the same time during placental and embryonic development.
Alternative Splicing↗
Clonal analysis of progenitor cells by interphase cytogenetics in patients with acute myeloid leukemia and myelodysplasia.
Interphase cytogenetics was used to investigate the clonal origin of bone marrow (BM) cells, peripheral blood (PB) cells, and in vitro cultured progenitor cells of five patients with acute myeloid leukemia (AML) and myelodysplasia (MDS). A new in situ hybridization (ISH) technique was used to examine the origin of the progenitor cells. Two patients with respectively, trisomy 8 and polyploidy as ISH marker were studied both at presentation and during remission. At presentation, the in vitro cultured clusters of both cases appeared diploid. Therefore, despite the abnormal growth patterns, the cultured progenitors could have been residual normal cells. Alternatively, they could have originated from a preleukemic clone with a normal karyotype. In both cases abnormal BM and/or PB cells (less than 6%) were detected with ISH during remission, indicating partially or completely clonal remissions in these patients. Both patients have relapsed. One patient with trisomy 10 as ISH marker was analyzed during myelodysplastic phase and after progression to AML. On both occasions, abnormally appearing clusters were cultured. However, only part of the clusters carried trisomy 10. The presence of a subclone characterized by trisomy 10 and an abnormally growing (pre)leukemic clone without trisomy 10 may explain this observation. Monosomy 1 and 17 were respectively used as ISH markers in two other AML patients. All in vitro cultured clusters carried the numerical abnormality. Long-term liquid cultures of these leukemias were performed for 10-20 days. In both cases, no residual normal clonogenic cells could be detected. Therefore, the selective growth advantage of normal progenitor cells in long-term marrow cultures could not be demonstrated in these two patients with leukemia. This paper illustrates the usefulness of ISH to study the biology of AML at the clonogenic level during preleukemic phase, active disease, remission, and under in vitro culture conditions. It is a sensitive technique which allows individual analysis of large numbers of small aggregates and single cells in culture.
Adult↗
In vitro response of blasts to IL-3, GM-CSF, and G-CSF is different for individual AML patients: factors that stimulate leukemic clonogenic cells also enhance Ara-C cytotoxicity.
In vivo, growth factors are currently investigated for their capacity to trigger leukemic stem cells into cycle and thus overcome kinetic drug resistance. In this study, the susceptibility of leukemic clonogenic cells to individual growth factors was related to cytosine-arabinoside (Ara-C) sensitivity. The effects of interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (G-CSF), granulocyte colony-stimulating factor (G-CSF), and combinations of these recombinant hematopoietic factors were tested on blast cells of nine acute myeloid leukemia (AML) patients. Growth factor responses were assessed in semi-solid clonogenic assay and in a 10-day liquid culture followed by clonogenic assay. Heterogeneity in growth factor response was observed in both test systems, resulting in a variable pattern for individual leukemias. In the majority of cases (six of nine) the response patterns in the semi-solid and liquid cultures were divergent. To test the Ara-C sensitivity, leukemic blasts were exposed in liquid to various concentrations of Ara-C in the absence and presence of preselected growth factors. After 10 days, the number of surviving leukemic colony-forming cells (CFU-L) was assessed. Exposure to Ara-C in the presence of optimal stimulatory factor(s) resulted in a 3- to 1000-fold increase of the Ara-C toxicity in seven patients. The Ara-C concentrations resulting in 50% inhibition of clonogenicity (ID50) were 0.48-123 x 10(-8) M Ara-C in the absence of stimulatory growth factors, versus only 0.12-0.40 x 10(-8) M Ara-C in the presence of these factors. In two patients, addition of one or more factors neither increased the number of CFU-L in liquid nor enhanced the Ara-C toxicity. Even in the absence of growth factors the ID50 values in these cases were as low as 0.20 and 0.28 x 10(-8) M Ara-C and in the same range as the ID50 values observed with maximum growth factor stimulation in the other seven patients. These results indicate that Ara-C cytotoxicity can be enhanced by individually selected, clonogenic cell growth-promoting hematopoietic factors.
Adolescent↗
Toxicity of idarubicin and doxorubicin towards normal and leukemic human bone marrow progenitors in relation to their proliferative state.
The effect of growth stimulation on the sensitivity of normal and leukemic human bone marrow progenitors to idarubicin and doxorubicin was studied. Clonogenic assays from colony-forming units of the granulocyte-macrophage lineage (CFU-GM) and leukemic clonogenic cells (CFU-L) were applied using human placenta conditioned medium (HPCM) as source of growth factors. Before seeding cells in clonogenic assay they were exposed to the anthracyclines for 2 h without preincubation, or following a 48 h preincubation period in the presence of HPCM. Drug concentrations used ranged from 0.001-0.1 microgram/ml for idarubicin and from 0.1-1.5 microgram/ml for doxorubicin. In addition, a limited number of bone marrow samples were exposed to the cytostatically active metabolite of idarubicin; idarubicinol (Idol; range 0.001-0.1 microgram/ml). Proliferation of CFU-GM and CFU-L during 48 h was measured by iododeoxyuridine (IdUrd) incorporation. Spontaneous proliferation of CFU-GM increased from 38 to 88% after 48 h stimulation by HPCM. The mean number of proliferating CFU-L increased from 40 to 77% when stimulated with HPCM. Doxorubicin inhibited colony formation of CFU-GM and CFU-L to 50% (IC50CFU-GM, IC50CFU-I) at mean concentrations of 0.355 microgram/ml and 0.103 microgram/ml when applied before preincubation with HPCM, and 0.108 microgram/ml and 0.055 microgram/ml when applied after preincubation. Idarubicin appeared the most potent drug in all experiments regardless of the preincubation procedure or sample origin, with average IC50CFU-GM and IC50CFU-L of 0.008 microgram/ml and 0.006 microgram/ml, respectively, when applied before preincubation with HPCM, and 0.006 microgram/ml and 0.005 microgram/ml when applied after preincubation with HPCM. Idarubicinol showed intermediate potency with average IC50CFU-GM of 0.022 microgram/ml and 0.023 microgram/ml when applied before and after preincubation with HPCM, respectively. In order to assess the effect of growth stimulation on drug sensitivity, samples were evaluated pair-wise (sensitivity of the same sample before vs. after preincubation with HPCM) and were submitted to the Wilcoxon test for matched pairs. Statistically significant enhancement of cytotoxicity was demonstrated for Doxorubicin vs. CFU-GM (p < or = 0.021) and a strong trend versus CFU-L (p = 0.06). The data further demonstrate that proliferation-dependency of doxorubicin toxicity is more pronounced for CFU-GM than for CFU-L. These data also show that idarubicin and idarubicinol toxicity is proliferation-independent. Idarubicin is relatively more potent than doxorubicin in suppressing the growth potential of low or nonproliferating progenitors.(ABSTRACT TRUNCATED AT 400 WORDS)
Acute Disease↗
Cryptosporidium species in ostriches.
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Animals↗
Assignment of the human deoxycytidine kinase (DCK) gene to chromosome 4 band q13.3-q21.1.
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Base Sequence↗
Allogeneic bone marrow transplantation for leukemia with marrow grafts treated by counterflow centrifugation.
Eighty consecutive patients were transplanted with human leukocyte antigen (HLA)-identical sibling marrow for acute myelogenous leukemia (AML, N = 29), acute lymphoid leukemia (ALL, N = 23), or chronic myelogenous leukemia (CML, N = 28). Donor marrow was depleted of lymphocytes using counterflow centrifugation. Median age of the recipients was 31 years. Pretransplant conditioning consisted of cyclophosphamide and fractionated total body irradiation (TBI). Graft failure occurred in 4 of 77 evaluable patients (5%). The probability of acute graft-versus-host disease (GVHD) > or = grade 2 at day 100 after transplantation was 15%. The projected 3-year estimate of extensive chronic GVHD was 12%. The projected 3-year probability of relapse was 30% in transplants for AML in first complete remission (CR1), 35% after transplantation for ALL in CR1, and 38% after transplantation for CML in first chronic phase (CP1). The projected 3-year probability of leukemia-free survival (LFS) was 56% after transplantation for AML-CR1, 42% in patients transplanted for ALL-CR1, and 49% after transplantation for CML-CP1. The chance of relapse was significantly reduced in a cohort of 72 standard risk patients conditioned with a regimen intensified by the addition of anthracyclines. This resulted in DFS at 4 years after BMT of 63% compared to 39% in a historical control group. Enrichment of the donor marrow with NK-cells did not increase the incidence of GVHD, but did neither decrease the relapse rate after BMT. In bone marrow transplantation for leukemia, counterflow centrifugation is a useful technique for the prevention of GVHD. Further efforts should be made to reduce relapse-rate, particularly in high risk patients.
Adolescent↗
Detection of single-strand breaks and base damage in DNA of blood cells from leukaemia patients receiving chemo- and radiotherapy.
Chemotherapy combined with total-body irradiation (TBI), a conditioning regimen for bone-marrow transplantation (BMT), causes lesions in the cellular DNA of the patients treated. To understand possible consequences of the DNA damage induced during such treatment, information is required about the nature of the damage, the level of induction and its persistence, and about the importance of the various lesions for cell-lethality and/or mutation induction. Recently, we developed a sensitive immunochemical method to quantify single-strand breaks (SSB) in the DNA of mammalian cells. In addition, a modification of the so-called alkaline elution technique was introduced which allows quantification of SSB together with base damage (SSB+BD). These methods have now been applied successfully to study the in vivo induction and repair of DNA damage in WBC of leukaemia patients who prior to BMT were treated with cyclophosphamide (CY) and received TBI. SSB and SSB+BD were determined after two treatments with CY (60 mg kg-1) followed by TBI (4.5-8.6Gy). The CY treatments gave rise to rather persistent SSB. In addition to these, radiation-induced SSB and SSB+BD could be detected shortly after TBI. However, 105 min after TBI, these SSB could be observed no longer, as a result of rapid repair.
Acute Disease↗