In vivo expansion of the endogenous B-cell compartment stimulated by radiation and serial bone marrow transplantation induces B-cell leukaemia in mice

Chronic lymphocytic leukaemia (CLL) is a malignancy of CD5(+) B cells. This B-cell lineage is established during ontogeny and replenished by the process of self-renewal. Spontaneous and induced leukaemias that frequently affect this lineage are thought to arise as a result of the frequent cell division required to maintain the population throughout adulthood and in response to repeated exposure to environmental antigens. In a series of bone marrow transplant (BMT) experiments performed in B6D2F1 mice, B-cell leukaemia occurred in recipients of serially transplanted syngeneic bone marrow. This study was therefore designed to determine the frequency and phenotype of the observed leukaemia. Male donor cells were initially transplanted into lethally irradiated female hosts and secondary (2 degrees ) BMT was performed at 3 months. At 1, 2, 3 and 16 months following primary (1 degrees ) BMT, and when 2 degrees BMT recipients developed leukaemia, animals were sacrificed and their tissues extensively examined. These analyses confirmed a host-derived CD5(+) transplantable B-cell leukaemia that was initiated in 50% of 1 degrees BMT recipients. With serial passage, the leukaemia became more aggressive and lost CD5 expression, suggesting transformation to a high-grade leukaemia/lymphoma. This previously unreported observation suggests that the combination of radiation and subsequent serial transplantation induces a proliferative stress to the host B-cell compartment that is causative in leukaemic transformation.

Improved method for distinguishing the human source of mosquito blood meals between close family members

We have developed a simple and relatively cheap method to distinguish the origin of mosquito blood meals between close family members, effective for both laboratory and field samples. Each blood meal was squashed on to filter paper and eluted overnight with 0.5 mL phosphate-buffered saline. Deoxyribonucleic acid (DNA) was extracted using a chemical matrix (Insta-gene) which bound to everything from the blood meal except DNA, which remained in the supernatant. Following extractions, reference DNA samples taken directly from finger-prick blood of human subjects and those from blood meals of unknown origin were amplified with human microsatellite markers using a thermal cycler. Polymerase chain reaction products were then run on an ABI gel (Automated Biosystems) to obtain a genotype for each sample. The DNA from each mosquito blood meal was then matched to an individual host. With laboratory samples, human DNA which had been extracted from mosquito blood meals up to 12 h after feeding could be used. One important application of this method will be to identify which members of a community are most at risk from vector-borne diseases. It also has numerous potential applications in studies of insect biting behaviour in both human and veterinary science.

Effect of pregnancy on exposure to malaria mosquitoes

Pregnant women attracted twice the number of Anopheles gambiae complex--the predominant African malaria-carrying mosquito--than did their non-pregnant counterparts. We postulate that physiological and behavioural changes that occur during pregnancy are responsible for increased attractiveness, which could be important in intervention strategies aimed at protecting this high-risk group against malaria.

Resistance of Holstein-Friesian cows to infestation by the cattle tick (Boophilus microplus)

In two experiments, the milk production of 59 Holstein-Friesian cows in mid lactation was measured over 1 week before artificial infestation with 2,500 or 5,000 Boophilus microplus larvae. Host resistance, the proportion of female ticks applied but not engorging was estimated from weekly counts of engorging female ticks of 4.5-8. 0mm long. Mean host resistance was 79 and 67% in two experiments. Host resistance was not significantly related to milk yield before infestation, to early pregnancy, or to parity. Culling the 10% of cattle with the least resistance to ticks would result in removal of 19-21% of ticks in a herd. The results suggest that selection to improve the existing low levels of resistance to B. microplus might be undertaken without compromising milk production. However, low levels of resistance among the cattle studied and difficulties in assessment of resistance are likely to limit the usefulness of selection within the Holstein-Friesian breed.

Evaluation of tickGARD(PLUS), a novel vaccine against Boophilus microplus, in lactating Holstein-Friesian cows

The effects of vaccination with the Bm 86 vaccine TickGARD(PLUS) against infestation with cattle tick (Boophilus microplus) and of holding cattle on a feedpad until 09:00 hours after the morning milking was tested on 40 mid lactation Holstein cattle using a factorial design. Vaccination resulted in a 56% reduction in tick numbers in the field over one generation, and a 72% reduction in laboratory measures of the reproductive efficiency of ticks. The liveweight gain of vaccinated cattle over 27 weeks was 18.6 kg higher than that of controls, and vaccinated cattle tended to have lower somatic cell count in milk (SCC). There were no other significant differences in measures of production. Cattle kept on the feedpad after the morning milking carried 26% more ticks than those returned immediately to their paddocks.

N-hydroxyurea and hydroxamic acid inhibitors of cyclooxygenase and 5-lipoxygenase

Two series of compounds (1 and 2) having structural features of the dual COX/5-LO inhibitor tepoxalin and the 5-LO inhibitor ABT-761 were prepared. Many of these hybrid compounds are potent COX and 5-LO inhibitors; two compounds (1a and 2t) inhibit eicosanoid biosynthesis in an ex vivo assay.

College of American Pathologists Conference XXXI on laboratory monitoring of anticoagulant therapy: laboratory monitoring of oral anticoagulant therapy

OBJECTIVE

To review the state of the art of laboratory monitoring of oral anticoagulant therapy, as reflected by the medical literature and the consensus opinion of recognized experts in the field, and to make recommendations for improvement in laboratory monitoring of oral anticoagulant therapy.

DATA SOURCES

Review of the medical literature, primarily from the last 10 years, and current laboratory practices by a panel of 8 international experts in the field of oral anticoagulant monitoring.

DATA EXTRACTION AND SYNTHESIS

After an initial assessment of the literature, key points were identified. Experts were assigned to do an in-depth review of the literature and current practices relevant to each of the key points and to prepare a summary of their findings and recommendations. A draft manuscript was prepared and circulated to every participant in the College of American Pathologists Conference XXXI on Laboratory Monitoring of Anticoagulant Therapy prior to the conference. Each of the key points and associated recommendations was then presented for discussion at the Conference. Recommendations were accepted if a consensus of the 26 experts attending the Conference was reached. The results of the discussion were used to revise the manuscript into its final form.

CONCLUSIONS

Consensus was reached on 12 recommendations concerning the laboratory monitoring of oral anticoagulant therapy. Detailed discussion of the rationale for each of these recommendations is found in the text of this article. Discussion of points on which consensus was not reached is also included in the text. It is hoped that widespread adoption of these recommendations will further improve the laboratory monitoring of oral anticoagulant therapy.

Production effects of cattle tick (Boophilus microplus) infestation of high yielding dairy cows

Forty mid-lactation Holstein-Friesian cows, 100% lot fed, were assigned to four groups for 15 weeks. Two groups of 10 cows were infested each week with a gradually increasing number of Boophilus microplus larvae, while the other two groups were maintained free of ticks. Milk yield and composition (including somatic cell count, SCC), liveweight, dry matter intake, packed cell volume (PCV) and total plasma protein (TPP) were measured throughout the 15 week period. By week 15, control cows produced 2.86 l more milk and 0.14 kg more butterfat each day and had gained 10.6 kg more liveweight than infested cows. Each engorging female tick was estimated to be responsible for the loss of 8.9 ml of daily mild production and 1.0 g of bodyweight over the trial period. Milk composition, PCV and TPP were not significantly affected by cattle tick infestation. The dry matter intake of control cows was 0.83 kg greater than infested cows in week 12.

The reliability of self-reported blood in urine and schistosomiasis as indicators of Schistosoma haematobium infection in school children: a study in Muheza District, Tanzania

The use of self-reported blood in urine and schistosomiasis by school children was investigated as a tool to estimate the prevalence of infection with Schistosoma haematobium and to identify infected individuals. A general questionnaire about common health problems, including questions about blood in urine and schistosomiasis, was administered by teachers to 25443 children in 137 primary schools in Muheza District, Tanzania. The prevalence of reported schistosomiasis was calculated for each school and used to select 15 schools across a range in prevalence. All children in the 15 schools (n = 2370) were interviewed again by a nurse and gave a urine sample which was subjected to a quantitative microscopical examination for the eggs of S. haematobium by filtration. The prevalence of reported schistosomiasis by the interview in the 15 schools correlated strongly with the prevalence reported during the questionnaire survey. The prevalence of reported schistosomiasis in the interview was strongly correlated with the prevalence of infection determined by microscopy and consistently under-estimated the latter by around 20% across a range in prevalence from 22% to 93%. The sensitivity of diagnosis by an interview increased almost linearly with the prevalence of infection, so that when the prevalence was high, more infected children reported schistosomiasis. The percentage of children who were correct in their self-diagnosis was independent of the prevalence of infection and of the mean concentration of eggs in urine, and averaged 75%. These findings suggest that self-reported schistosomiasis is a useful method to estimate the prevalence of infection in schools and might be used to identify infected individuals.

A case of Isaacs' syndrome with associated central nervous system findings

We report a 44-year-old female with Isaacs' syndrome, peripheral motor neuropathy, and features of central pontine myelinolysis (CPM). The patient presented with stiffness and muscle spasms accompanied by profound sweating. She also had bilateral Babinski signs. Electrodiagnostic abnormalities were characteristic of Isaacs' syndrome. Magnetic resonance imaging demonstrated features of CPM. She gained modest relief from baclofen, valproate, and diazepam. She improved dramatically following plasmapheresis and continued to recover on prednisone. She was weaned from steroids without relapse.

Evaluation of the antiinflammatory activity of a dual cyclooxygenase-2 selective/5-lipoxygenase inhibitor, RWJ 63556, in a canine model of inflammation

Sterile perforated polyethylene spheres (wiffle golf balls) were implanted s.c. in beagle dogs. A local inflammatory reaction was elicited within the spheres by injecting carrageenan. Changes in leukocyte count, prostaglandin E2, thromboxane B2 and leukotriene B4 levels were monitored in fluid samples collected over a 24-hr period. Blood samples were also collected at various time points and analyzed for prostaglandin E2 and leukotriene B4 production after ex vivo calcium ionophore treatment. Effects of standard antiinflammatory agents (aspirin, indomethacin, dexamethasone, tenidap and zileuton) and newer cyclooxygenase-2 (COX-2) selective agents (nimesulide, nabumetone and SC-58125) were determined after oral administration. Ex vivo inhibition of cyclooxygenase product synthesis (prostaglandin E2, thromboxane B2) in whole blood was used as an indicator of activity for the constitutive COX-1 isoform, although inhibition of the synthesis of these mediators in the chamber exudate during an inflammatory process is believed to represent COX-2 inhibition. Treatment effects on leukotriene B4 production were also determined both ex vivo in whole blood and in the fluid. All of the compounds tested, except aspirin, inhibited leukocyte infiltration into the fluid exudate. Inhibitors that exert their effects on both isozymes of cyclooxygenase attenuate production of cyclooxygenase metabolites in both the inflammatory exudate and in peripheral blood ex vivo, although COX-2 selective inhibitors only demonstrated activity in the exudate. A 5-lipoxygenase inhibitor (zileuton), a corticosteroid (dexamethasone) and a dual COX-2 selective/5-lipoxygenase inhibitor (RWJ 63556) had similar profiles in that they all inhibited cell infiltration and eicosanoid production in the fluid and also attenuated leukotriene B4 production in both the fluid and blood.

The control of microvascular permeability and blood pressure by neutral endopeptidase

Plasma extravasation from postcapillary venules is one of the earliest steps of inflammation. Substance P (SP) and bradykinin (BK) mediate extravasation and cause hypotension. The cell-surface enzyme neutral endopeptidase (NEP) inactivates both peptides. Thus, absence of NEP may predispose development of inflammation and hypotension. We examined these possibilities in mice in which the NEP gene was deleted by homologous recombination. There was widespread basal plasma extravasation in postcapillary venular endothelia in NEP-/- mice, which was reversed by recombinant NEP and antagonists of SP (NK1) and BK (B2) receptors. Mean arterial blood pressure was 20% lower in NEP-/- animals, but this was unaffected by reintroduction of recombinant NEP and the kinin receptor antagonists. The hypotension was also independent of nitric oxide (NO), because NEP-/- mice treated with a NO synthase inhibitor remained hypotensive relative to the wild type. Thus, NEP has important roles in regulating basal microvascular permeability by degrading SP and BK, and may regulate blood pressure set point through a mechanism that is independent of SP, BK and NO. The use of NEP antagonists as candidate drugs in cardiovascular disease is suggested by the blood pressure data reported herein.

N-(5-substituted) thiophene-2-alkylsulfonamides as potent inhibitors of 5-lipoxygenase

Compound 4k N-[5-(4-fluoro)phenoxythien-2-yl]methanesulfonamide is representative of a new class of potent inhibitors of 5-lipoxygenase (5-LO). These versatile compounds exhibit dose-dependent inhibition of 5-LO with IC50s ranging from 20-100 nM in the rat basophilic leukemia (RBL-1) cell homogenate assay and submicromolar IC50s in both the RBL-1 and human peripheral blood leukocyte (PBL) whole cell assays. Compound 4k also showed significant anti-inflammatory activity in the adjuvant arthritic rat at an oral dose of 3 mg/kg.

Comparison of radiographer/radiologist double film reading with single reading in breast cancer screening

OBJECTIVES - To assess the efficacy of dual film reading in screening mammography with a suitably trained radiographer as the second reader and to determine a suitable decision model for radiographer/radiologist double reading. SETTING - Three breast screening centres in South Thames (West) region. METHODS - Seven radiographers with prior film reading training double read 17 202 screening mammograms with a radiologist. Screening performance of radiographers and radiologists was assessed taking into account interval cancers. The efficacy of radiographer/radiologist double reading was assessed in terms of changes in sensitivity and specificity compared with radiologist single reading. RESULTS - Radiographers yielded equivalent sensitivity but lower specificity than radiologist film readers. The effect of double reading between radiographer/radiologist pairs was an increase in sensitivity of 6-4%, which was achieved at the cost of a 0-6% decrease in specificity. This was reached by a decision system involving radiologists' review of radiographer queries and recall classifications. If all radiographer queries were recalled a large increase in sensitivity would be counterbalanced by an equally large decrease in specificity. CONCLUSIONS - Radiographer/radiologist double reading resulted in similar increases in sensitivity as those previously reported in radiologist double reading studies. Radiologist review of radiographer reported abnormalities is a suitable means by which to limit excess recall.

Radiographers as film readers in screening mammography: an assessment of competence under test and screening conditions

The aim of this study was to investigate the potential of radiographers as film readers in screening mammography. Seven radiographers received training in mammogram interpretation at a National Health Service (NHS) Breast Screening Training Centre. Film reading performance was assessed over a period of 1 year after training with test sets of selected screening mammograms. Actual screening performance on contemporary screening mammograms was monitored after training in relation to radiologist decisions and screening outcome. It was found that trained radiographers read mammograms to a standard comparable with that of radiologists. Film reading skills were maintained consistently over the period of this study and transferred to actual screening performance. It was concluded that radiographers could play a useful role as second readers in screening mammography. Training needs have to be assessed in relation to the role the film reading radiographer is to adopt.

Encephalomyeloradiculopathy of infectious or parainfectious etiology--a new entity?

Between 19 March 1990 and 24 December 1992, six persons in Nova Scotia presented with a unique neurological illness. A prodrome of fever and headache was followed by neurogenic bladder, transverse myelitis, and encephalopathy in association with mononuclear pleocytosis of the CSF and nerve-conduction study findings consistent with polyradiculopathy. The spinal cords of three of the patients appeared abnormal on myelograms or magnetic resonance imaging studies. No microbial agent was isolated or demonstrated serologically. All of the patients were treated with antimicrobial agents and corticosteroids. Three recovered completely, but neurogenic bladder persisted in the remaining three. We suggest that this group of patients manifested an encephalomyeloradiculopathy that is likely a new clinical entity of infectious or parainfectious etiology.

Adjuvant intraoperative photodynamic therapy in experimental colorectal cancer

A reliable animal model for quantitative assessment of local recurrence of colorectal cancer was developed using colo26 tumour in BALB/c mice. The effect of adjuvant intraoperative photodynamic therapy to potentially curative surgery on local recurrence was examined in four study and four control groups. Study groups received 15 mg kg-1 Photofrin (a photosensitizing drug) 24 h before surgery. After 'curative' tumour excision, the tumour beds were illuminated with either 630 nm or 510 nm laser light each at 40 and 70 J/cm-2. Controls received surgery only, surgery and Photofrin only or surgery and either 630 nm or 510 nm light. The local recurrence rates at 70 days were 17-33 per cent in the study groups compared with 83-100 per cent in the control groups (P < 0.001; log rank test). Photodynamic therapy is capable of reducing local recurrence following potentially curative excision of tumour in this model.

Antithrombotic therapy. An abbreviated reference for clinicians

Antithrombotic therapy is a mainstay in the treatment of patients with thromboembolic diseases of the arterial and venous circulatory systems. Continued work and investigation has provided much-needed information directly applicable to meeting high standards of patient care. The American College of Chest Physicians Consensus Conference on Antithrombotic Therapy has been instrumental in developing guidelines. This article is a synopsis of the proposed guidelines, including recent updates and information that will likely influence future recommendations.

Synthesis and 5-lipoxygenase inhibitory activities of some novel 2-substituted 5-benzofuran hydroxamic acids

A series of 2-substituted benzofuran hydroxyamic acids were synthesized as rigid analogs of simple (benzyloxy)phenyl hydroxamates, evaluated for their in vitro and in vivo 5-lipoxygenase activity and found to be potent inhibitors of the enzyme. Substituents which enhanced lipophilicity near the 2-position of the benzofuran nucleus increased inhibitor potency but reduced oral activity. Incorporation of small polar substituents such as methoxymethylene, hydroxymethylene, and amino (urea) on the acyl group led to more consistent oral activity. The most potent inhibitors of this series in vitro were N-hydroxy-N-[1-(2-phenyl-5-benzofuranyl)-ethyl]furancarboxamide (12) and methyl 5-[N-hydroxy-N-[1-(2-(3,4,5-trimethoxyphenyl)-5-benzofuranyl]ethyl]-5- oxopentanoate (17), both with IC50 values of 40 nM, and in vivo the most potent compound was N-hydroxy-N-[1-(2-phenyl-5-benzofuranyl)ethyl]urea, 20, with an ED50 = 10.3 mg/kg.