First Report of Downy Mildew Caused by Peronospora trigonellae on Fenugreek in the United States

Fenugreek (Trigonella foenum-graecum) is a member of the Fabaceae family and is grown worldwide for culinary and medicinal purposes. The leaves are used as an herb while the seeds are used whole, ground as a spice, or germinated and used as sprouts. In November 2008, a fenugreek plant exhibiting leaf spotting and severe stunting was submitted to the CDFA Plant Pest Diagnostics Laboratory from the Los Angeles County Plant Diagnostic Laboratory. The county had received the sample from a homeowner who reported severe dieback of the fenugreek in his backyard planting. The fenugreek is grown by the resident as an annual and is propagated each year from the previous crop's seed. The seed was originally obtained from a local ethnic grocery store in Lakewood, CA. The homeowner stated that he had noticed symptoms for a number of years and that they seemed especially severe during the winter months. The adaxial surfaces of the leaves exhibited small chlorotic spots often at the leaf margins, while the abaxial surfaces exhibited a grayish violet, felty growth. Conidiophores found on the underside of the leaves branched dichotomously 6 to 10 times and were terminally forked. Conidiophores measured 280 to 525 μm (average 420 μm) with slightly swollen bases (7.5 to 10 μm broad). Conidia were slightly pigmented, oblong to ellipsoid, and measured 23 to 33 × 18 to 23 μm (average 27.8 × 20.3 μm). Globose oospores with verruculose walls measured 30 to 40 μm in diameter (average 36.1 μm) and were found embedded in the leaf tissue of older lesions. The pathogen was identified morphologically as Peronospora trigonellae Gaum. (3). Sequences of a portion of the rDNA, including the internal transcribed spacer regions, were obtained using primers DC6 and ITS6 (1). Sequence data for P. trigonellae had not previously been entered into GenBank and no identity was obtained. Pathogenicity experiments attempted by spraying healthy fenugreek seedlings with conidial suspensions were unsuccessful, presumably because of the age of the inoculum. Since fenugreek is not commercially grown in California, the economic importance of this disease is limited. Although P. trigonellae has been reported on fenugreek in Algeria, India, Pakistan, and the United Kingdom (2-4), to our knowledge, this is the first report of its occurrence in California and the United States. A specimen of P. trigonellae has been deposited in the U.S. National Fungus Collection (BPI 879153). References: (1) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (2) D. F. Farr et al. Fungal Databases. Systematic Mycology and Microbiology Laboratory. Online publication. ARS, USDA, 2009, (3) E. A. Gaumann. Beitr. Kryptogamenflora Schweiz 5:216, 1923. (4) D. R. Jones et al. Plant Pathol. 56:891, 2007.

Outgrowth of a transformed cell population derived from normal human BM mesenchymal stem cell culture

BACKGROUND

Human mesenchymal stem cells (hMSC) have been isolated and characterized extensively for a variety of clinical applications. Yet it is unclear how the phenomenon of hMSC plasticity can be safely and reasonably exploited for therapeutic use.

METHODS

We have generated mesenchymal stem cells (MSC) from normal human BM and identified a novel cell population with a transformed phenotype. This cell population was characterized by morphologic, immunophenotypic, cytogenetic analyzes and telomerase expression. Its tumorigenicity in NOD/SCID mice was also studied.

RESULTS

A subpopulation of cells in hMSC culture was noted to appear morphologically distinct from typical MSC. The cells were spherical, cuboidal to short spindle in shape, adherent and exhibited contact independent growth. Phenotypically the cells were CD133(+), CD34(-), CD45(-), CD90(low), CD105(-), VEGFR2(+). Cytogenetic analysis showed chromosome aneuploidy and translocations. These cells also showed a high level of telemerase activity compared with typical MSC. Upon transplantation into NOD/SCID mice, multiple macroscopic solid tumors formed in multiple organs or tissues. Histologically, these tumors were very poorly differentiated and showed aggressive growth with large areas of necrosis.

DISCUSSION

The possible explanations for the origin of this cell population are: (1) the cells represent a transformed population of MSC that developed in culture; (2) abnormal cells existed in the donor BM at rare frequency and subsequently expanded in culture. In either case, the MSC culture may provide a suitable environment for transformed cells to expand or propagate in vitro. In summary, our data demonstrate the potential of transformed cells in hMSC culture and highlight the need for karyotyping as a release criteria for clinical use of MSC.

Ex vivo expansion of mafosfamide-purged PBPC products

BACKGROUND

Multiple studies have demonstrated that 'purging' of autografts with 4-hydroperoxycyclophosphamide (4HC) or the related compound mafosfamide (Mf), to eradicate residual leukemia, produces the best results associated with autologous blood and marrow transplantation for AML. However, 4HC purging results in prolonged aplasia. Therefore, we evaluated the potential of ex vivo expansion of Mf-treated CD34+ cells from mobilized PBPC.

METHODS

CD34+ cells were isolated from PBPC products and treated with 30 microg/mL Mf. The Mf-treated CD34+ cells were washed and cultured for 14 days in StemLine II-defined media containing recombinant human (rh) SCF, G-CSF and thrombopoietin (Tpo).

RESULTS

Treatment with Mf resulted in 90% killing of progenitor cells (GM-CFC) but maintenance of SCID-repopulating cells (SRC). Ex vivo culture of the Mf-treated CD34+ cells resulted in decreased cell numbers (10-20% of the starting cell dose) during the first week. Nevertheless, in the second week of culture the total cell numbers expanded to approximately 20-fold above starting cell numbers and progenitor cells returned to approximately pre-treatment levels.

DISCUSSION

These studies demonstrate the potential of ex vivo culture to expand both total cell numbers and progenitor cells following treatment of PBPC CD34+ cells with Mf. Clinical studies are currently being initiated to evaluate the engraftment potential of these purged and expanded products.

Ex vivo expansion of cord blood mononuclear cells on mesenchymal stem cells

BACKGROUND

Cord blood (CB) cells are being used increasingly as a source of hematopoietic cells to support high dose chemotherapy. However, CB units contain low numbers of cells, including CD34+ cells, and thus their use is associated with significant delays in engraftment of neutrophils and platelets. Exvivo expansion of CB has been proposed to increase the numbers of cells available. We and others have reported the requirement of CD34 selection for optimal expansion of CB products'; however, the selection of frozen CB products in clinical trials results in significant loss of CD34+ cells, with a median recovery of 50, but less than 40% recovery in more than one-third of products. In the present studies we evaluated the potential of mesenchymal stem cells (MSC) to support ex vivo expansion of unselected CB products.

METHODS

Mononuclear cells (MNC) from CB products were isolated and cultured on preformed MSC layers in T150 flasks containing 50 mL Stemline II media plus hematopoietic growth factors. Various culture conditions were compared for optimal expansion of the CB MNC.

RESULTS

Ex vivo expansion of CB MNC on MSC resulted in 10- to 20-fold expansion of total nucleated cells, seven- to 18-fold expansion of committed progenitor cells, two- to five-fold expansion of primitive progenitor cells and 16- to 37-fold expansion of CD34+ cells.

DISCUSSION

These studies demonstrated significant expansion of CB products without CD34 cell selection using culture conditions that are clinically applicable. Our current focus is to initiate clinical trials to evaluate the in vivo potential of CB cells expanded with these conditions.

Effective utilization of erythropoietin with intravenous iron therapy

INTRODUCTION

Iron replacement therapy reduces the demand for erythropoietin (EPO) in some dialysis patients. It has been postulated that iron supply to the bone marrow is a rate-limiting step in the process of erythropoiesis under erythropoietin stimulation.

METHODS

We evaluated the economic benefit of intravenous iron therapy for this purpose in a prospective, non-blinded study of 22 haemodialysis patients, 16 male, six female, mean age 62 years (range 24-80 years). All patients had a serum ferritin (SF) of < or = 60 microg/L, despite oral iron therapy. Patients with high aluminium and/or parathyroid hormone (PTH) levels, underlying bleeding/haematological disorders or active inflammatory diseases were excluded. Patients were established on subcutaneous EPO and given intravenous iron over seven consecutive dialysis sessions (total dose 1050 mg) and supplemental monthly doses with regular monitoring for 4 months.

RESULTS

The median EPO dose was 4000 units/week (mean 6050 units/week) pre-treatment and 2000 units/week (mean 3700 units) at 6 weeks post intravenous iron therapy (P=0.03). No serious adverse events occurred in the 154 treatment sessions of intravenous iron. Mean haemoglobin (Hb) level remained constant at 6 and 12 weeks (P=0.087). Serum ferritin levels (P< 0.0001) rose significantly, while a reduction in transferrin saturation (TS) became significant at the end of the study (P=0.0047). The use of intravenous iron allowed a substantial monthly cost saving per patient in our unit.

CONCLUSION

Intravenous iron therapy is a safe and cost-effective method for maintaining or improving Hb levels with a more effective utilization of EPO in patients with low SF levels despite oral iron therapy.

Evaluation of RBC ferritin and reticulocyte measurements in monitoring response to intravenous iron therapy

Intravenous (IV) iron therapy can reduce erythropoietin (EPO) requirements in dialysis patients. Monitoring this response accurately is difficult. Estimation of red blood cell ferritin (RBCFer) and reticulocyte indices may give additional valuable information about iron availability to the erythroblasts (erythron). We evaluated the use of RBCFer, mean hemoglobin content of reticulocytes (CHr), and mean hemoglobin concentration of reticulocytes (CHCMr) in a prospective, nonblinded study of 22 hemodialysis patients (16 men and six women with a mean age of 62 years [range, 24 to 80 years]). All patients had an initial serum ferritin of < or = 60 microg/L. Patients with features known to produce EPO resistance and underlying bleeding/hematologic disorders were excluded. Patients were established on subcutaneous EPO and given IV iron therapy. The mean hemoglobin level remained constant throughout the study (P = 0.087). Serum ferritin and RBCFer increased significantly (P < 0.001 and 0.015, respectively) while a reduction in transferrin saturation became significant at the end of the study (P = 0.0047). A sharp increase in reticulocytes occurred in the first 14 days after commencement of IV iron, and there was an initial decrease in the percentage of hypochromic RBCs. An early decline in RBCFer was apparent. CHr increased with IV iron, indicative of increased iron supply to the developing erythron. Measurement of RBCFer and CHr provide evidence of increased iron supply for erythropoiesis during IV iron therapy. These measures help identify patients with functional iron deficiency and allow more accurate monitoring of response to IV iron therapy.

Public understanding of science

The scientist's lament about public understanding of science is often heard. But scientific understanding is not merely a matter of scientific literacy; it also embraces issues of trust in scientists, doctors, and sources of information. People have an appetite for scientific information, and they are good at sifting the information relevant to their lives. Nonetheless, the onus will increasingly be on the scientist to explain scientific findings in ways that a range of public can use. So, we need to improve the scientist's understanding of the public.

Public understanding of medical discovery

In February last year, the popular British magazine Woman's Own published an article headed 'Would you take a breast cancer test?'. It suggested that, 'women who have a family history are thought to be more at risk. Now, however, scientists have developed a blood test that can show if we're likely to get cancer. But would you want to know?'.

Life in the laboratory: public responses to experimental biology

Present-day public attitudes to biological manipulation are ambivalent, many surveys show. This paper explores evidence of earlier attitudes to experimental biology, before survey data exists, by examining published responses in the press to the idea that biologists would 'create life'. This remarkable claim achieved wide currency in the early years of this century, particularly linked to the work of two prototypical 'visible scientists': Jacques Loeb and Alexis Carrel. Analysis of press responses to accounts of their work reveals deep disquiet about its possible implications, at a time when science and technology in general were regarded very positively. The evidence is augmented by studying commentary on a Presidential Address by Edward Schafer to the British Association meeting of 1912. It is concluded that feelings of ambivalence toward the manipulative power of biology are apparent at a very early stage in the development of modern biology, and that this makes it implausible that more recent manifestations of such ambivalence can be ascribed to some generalized 'anti-science' sentiment which has gathered strength in recent years.

Bacterial endocarditis of the tricuspid valve after insertion of a central venous catheter

Central venous cannulation is a commonly used technique in the management of seriously ill patients. In experienced hands, the complication rate is low and primarily includes sepsis, thrombosis and local trauma. For chronic indwelling central venous catheters, thrombus formation within the right atrium has been described, particularly in premature infants, and a recent case has been reported in an adult. Valvular damage in the right heart is recognised and more often diagnosed at autopsy. This report describes the presence of tricuspid vegetations in a diabetic woman, related to the insertion of a central venous cannula.

Progressive systemic sclerosis, immunosuppression and necrotising arteritis: cause or effect?

Necrotising arteritis is rare in progressive systemic sclerosis (PSS). We report a patient with PSS who died with renal failure due to necrotising arteritis and segmental crescentic glomerulonephritis more typical of polyarteritis nodosa. Possible pathogenetic mechanisms are discussed. Renal biopsy is an important investigation in PSS, but is especially important in patients without hypertension, as other pathology needs to be excluded.

Hyperkalaemia in cyclosporin-treated renal allograft recipients

Mean serum potassium levels were significantly higher for 9 months in renal allograft recipients receiving cyclosporin than in those receiving prednisolone and azathioprine. Sustained hyperkalaemia (serum potassium 6.0-7.1 mmol/l) inappropriate for their renal function (glomerular filtration rate 21-36 ml/min) developed in seven of forty-three cyclosporin-treated patients. All seven patients had hyperchloraemic acidosis; four were able to acidify their urine to pH less than or equal to 5.4. Six of the seven patients were hypertensive and receiving beta-blockers; one had had bilateral nephrectomy. Despite hyperkalaemia, plasma aldosterone levels were within the normal range in five patients and raised in two. During moderate sodium restriction, plasma renin activity was low or low-normal in five of the seven patients. In these patients a combination of hypoaldosteronism and renal tubular damage leading to a tubular defect of potassium and hydrogen ion secretion is the apparent cause of the hyperkalaemia and hyperchloraemic acidosis. Hyporeninaemia caused by beta-blockade probably blunts the aldosterone response to hyperkalaemia, thereby worsening it.

The effects of two different dosage regimens of sulphinpyrazone on platelet function ex vivo and blood chemistry in man

When sulphinpyrazone (either 200 mg q.d.s. for 7 days or 400 mg b.d.s. for 5 days) was administered to human volunteers, inhibition of platelet function was observed ex vivo. The inhibitory effect was measured by the increase in the concentration of sodium arachidonate required to cause platelet aggregation and a decrease in the biosynthesis by the platelets of malondialdehyde from added sodium arachidonate. ADP-induced primary platelet aggregation was statistically significantly inhibited only on 1 day of the two studies. The inhibitory effect did not correlate with the plasma concentrations of unchanged sulphinpyrazone nor with its sulphone metabolite but correlated with the plasma concentration of the thioether metabolite (r = 0.577, p less than 0.001). Platelet count, plasma fibrinogen, beta-thromboglobulin, urea and creatinine concentrations were not changed by the drug but there was a clinically insignificant increase in bleeding time in all but one subject.

Inhibition of Human Platelet Function Induced by Sulphinpyrazone

A single 400 mg dose of sulphinpyrazone (S) administered orally to 5 volunteers inhibited arachidonic acid (AA)-induced platelet aggregation and platelet MDA production ex vivo biphasically. The initial inhibitory phase coincided with the maximum plasma concentration of S but the second phase occurred 24 h after dosing when no plasma S was detectable. At 2 h the concentration of AA inducing half-maximal aggregation was increased 1.95 times and at 24 h by 1.61 times. Dosing 7 volunteers with 200 mg q.d.s. for 7 days and 5 volunteers with 400 mg b.d.s. for 5 days also led to inhibitory activity against AA-induced platelet aggregation and MDA production which declined to zero 48 h after the last dose. Platelet count, fibrinogen, F VIII, β-TG and AT III were not influenced by the longer term treatment but bleeding time was slightly extended in all but one subject.

Abnormal Ristocetin-Aggregation of Platelets in Uraemia and on Haemodialysis Therapy

Impaired platelet aggregation to ADP and collagen is recognised in uraemia and the loss of normal platelet function contributes to the prolonged capillary bleeding time observed in uraemia. in von Willebrand’s disease prolongation of capillary bleeding time is associated with impaired platelet aggregation to ristocetin because of a relative or absolute deficiency of the Factor VIII-Ristocetin Cofactor. We have studied platelet aggregation to ristocetin and Factor VIII coagulant activity (CA) and related antigen (RA) in 14 uraemic and 28 dialysed patients. Ristocetin aggregation (delta-0.D/min) was significantly less in uraemia (50 ± 21: m ± S.D) and in dialysis patients (38 ± 18) than in controls (78 ± 20). Factor VIII CA and RA were significantly higher in uraemic and dialysed patients than in controls.

In crossover studies plasma from uraemic patients either enhanced or did not change ristocetin aggregation of normal platelets but plasma from dialysed patients impaired ristocetin aggregation of normal platelets. Plasma from dialysed patients was not contaminated by heparin. Thus in uraemia impaired platelet aggregation to ristocetin is unlikely to be due to a Factor VIII deficiency and may be due to a membrane defect as in Bernard-Soulier disease. in dialysed patients’ plasma there appears to be an additional circulating inhibitor of platelet-ristocetin interaction.

Abnormal Ristocetin-Aggregation of Platelets in Uraemia and on Haemodialysis Therapy

Impaired platelet aggregation to ADP and collagen is recognised in uraemia and the loss of normal platelet function contributes to the prolonged capillary bleeding time observed in uraemia. In von Willebrand’s disease prolongation of capillary bleeding time is associated with impaired platelet aggregation to ristocetin because of a relative or absolute deficiency of the Factor VIII-Ristocetin Cofactor. We have studied platelet aggregation to ristocetin and Factor VIII coagulant activity (CA) and related antigen (RA) in 14 uraemic and 28 dialysed patients. Ristocetin aggregation (delta-0.D/min) was significantly less in uraemia (50 ± 21: m ± S.D) and in dialysis patients (38 ± 18) than in controls (78 + 20). Factor VIII CA and RA were significantly higher in uraemic and dialysed patients than in controls.

In crossover studies plasma from uraemic patients either enhanced or did not change ristocetin aggregation of normal platelets but plasma from dialysed patients impaired ristocetin aggregation of normal platelets. Plasma from dialysed patients was not contaminated by heparin. Thus in uraemia impaired platelet aggregation to ristocetin is unlikely to be due to a Factor VIII deficiency and may be due to a membrane defect as in Bernard-Soulier disease. In dialysed patients’ plasma there appears to be an additional circulating inhibitor of platelet-ristocetin interaction.

Regular Haemodialysis Therapy (RDT) Induces A Prothrombotic State

To determine whether activation of coagulation factors and platelets, reported during haemodialysis results in a prothrombotic state we have studied indices of coagulability in 15 undialysed and 32 dialysed uraemic patients. Mean plasma fibrinogen (g/1) in uraemic patients (3.53) was significantly higher than in controls (2.45) and rose further in dialysed patients (3.81). Factor VIII coagulant activity (CA) was greater in dialysed (202 ± 15.9%) than in undialysed uraemic patients (184 ± 14.2%) both being significantly greater than control (84 ± 3.9). Similarly Factor VIII related antigen (RA) was higher in dialysed patients (216 ± 18.5%) than uraemics (156 ± 9.6%) (control = 94 ± 5.6%). The mean RA/CA ratio and the frequency of a high RA/CA ratio (< 1.5), an index of thrombin induced consumption of Factor VIII-CA and intravascular coagulation, were higher in dialysed than nondialysed patients.

Despite the higher circulating levels of procoagulants and the evidence of thrombin activation the availability of heparin cofactor-antithrombin III (AT III) was lower in dialysed (154%) than in uraemic patients (159%) though in both groups AT III levels were higher than in controls (100%).

These results indicate that RDT is associated with a prothrombotic state which is not completely compensated for by an increase in antithrombin III.

Inhibition of Human Platelet Function Induced by Sulphinpyrazone

A single 400 mg dose of sulphinpyrazone (S) administered orally to 5 volunteers inhibited arachidonic acid (AA)-induced platelet aggregation and platelet MDA production ex vivo biphasically. The initial inhibitory phase coincided with the maximum plasma concentration of S but the second phase occurred 24 h after dosing when no plasma S was detectable. At 2 h the concentration of AA inducing half-maximal aggregation was increased 1.95 times and at 24 h by 1.61 times. Dosing 7 volunteers with 200 mg q.d.s. for 7 days and 5 volunteers with 400 mg b.d.s. for 5 days also led to inhibitory activity against AA-induced platelet aggregation and MDA production which declined to zero 48 h after the last dose. Platelet count, fibrinogen, F VIII; ß-TG and AT III were not influenced by the longer term treatment but bleeding time was slightly extended in all but one subject.