High-efficiency gene transfer to recalcitrant plants by Agrobacterium tumefaciens

 Agrobacterium tumefaciens efficiently transforms most plants. A few dicotyledonous plants and most monocotyledonous plants are, however, recalcitrant to A. tumefaciens infection. We investigated whether the constitutive synthesis of a high level of the T-strand DNA intermediate can improve the transformation efficiency of plants. We previously described a mutation in the vir gene regulator virG, virGN54D, that allows constitutive expression of the vir genes. We also described the isolation of a mutant plasmid that is present at a significantly high level in A. tumefaciens. The two mutations were combined to produce an A. tumefaciens strain that synthesizes a high level of T-strand DNA in an inducer-independent manner. DNA transfer efficiency of the mutant was measured by monitoring β-glucuronidase (GUS) expression in a transient transfer assay. A significant increase in the efficiency of DNA transfer to both rice and soybean was observed with the double mutant. The presence of virGN54D had a major positive effect on transformation efficiency.

An audit into homeless families in temporary accommodation

This article describes a clinical audit project undertaken in a number of hostels providing temporary housing for homeless families and individuals in Hinckley, Leicestershire. The audit, carried out over a 6-week period, aimed to collect information about the health and social needs of the residents in the hostels to determine whether an on-site dedicated health visiting service would be of any benefit to them. Family members housed in three council-run hostels were interviewed and a detailed questionnaire was completed. This was used to gather information about the facilities in the hostels, the nutritional and mental status and health and social needs of the residents, the uptake of childhood immunizations and child health surveillance. It also provided information about the resident families' contact with their family health visitor. Families were living in cramped conditions with shared facilities and no safe play areas for their children. The audit clearly demonstrated that the residents living in the hostels had a range of health problems similar to those described in the literature about the homeless. As a result of the audit, a number of recommendations were made which are discussed in this article.

Prospective studies of cothymia (mixed anxiety-depression): how do they inform clinical practice?

We suggest that the diagnosis of mixed anxiety depression at syndromal level (i.e. both anxiety and depressive diagnoses present in the same person and given equal status) is valuable clinically and should be introduced into the formal classification of neurotic and mood disorders. Evidence is given from a systematic review that cothymia has a significantly worse outcome than either an anxiety or a depressive diagnosis alone (p < 0.0001). Long-term follow-up data in a 12-year outcome study of neurotic disorder reinforce this finding both with regard to social functioning and the clinical course of anxiety and depressive disorders; these were significantly worse (P < 0.001 and P < 0.02 respectively) in those with cothymia compared with single anxiety disorders. These outcome differences are much greater than those between anxiety and depressive disorders alone.

In search of susceptibility genes for type 2 diabetes in West Africa: the design and results of the first phase of the AADM study

PURPOSE

The purpose of this study is to map type 2 diabetes susceptibility genes in West African ancestral populations of African-Americans, through an international collaboration between West African and US investigators.

DESIGN AND METHODS

Affected sib-pairs (ASP) along with unaffected spouse controls are being enrolled and examined in West Africa, with two sites established in Ghana (Accra and Kumasi) and three in Nigeria (Enugu, Ibadan, and Lagos). Eligible participants are invited to study clinics to obtain detailed epidemiologic, family, and medical history information. Blood samples are drawn from each participant to measure glucose, insulin, C-peptide, total cholesterol, LDL, HDL, triglycerides, albumin, creatinine, urea, uric acid, total calcium and to detect autoantibodies to glutamic acid decarboxylase (GAD). DNA is isolated from frozen white blood cells obtained from 20 ml of EDTA whole blood samples.

RESULTS

With full informed consent, 162 individuals from 78 families have been enrolled and examined since the Africa America Diabetes Mellitus (AADM) study began in June of 1997. Logistics of field examinations and specimen shipping have been successfully established. At the end of the third year of field activity (September 2000) the AADM study will have enrolled and performed comprehensive examination on 400 ASP with type 2 diabetes, for a minimum of 800 cases and 200 controls from Ghana and Nigeria. At the current participation rate, the goal of 400 sib-pairs and 200 controls will be met before the scheduled closing date.

CONCLUSIONS

The AADM study will create a comprehensive epidemiologic and genetic resource that will facilitate a powerful genome-wide search for West African susceptibility genes to type 2 diabetes.

A comprehensive interactive competency program. Part II: Implementation, outcomes, and followup

The department of medicine/oncology nursing of an academic medical center developed and implemented a comprehensive interactive competency program. The program proved to be valuable to the individual nurse and the organization. Part II of this two-part series describes the implementation, outcomes, and followup of the program.

Intravenous azathioprine in severe ulcerative colitis: a pilot study

OBJECTIVE

Azathioprine use in acute ulcerative colitis has been limited by its perceived long onset of action. The aim of this study was to determine the safety and clinical effect of an i.v. loading dose of azathioprine in the setting of severe steroid refractory ulcerative colitis.

METHODS

Nine hospitalized patients with severe steroid refractory ulcerative colitis were enrolled. Patients 1-3 received 20 mg/kg i.v. azathioprine over 36 h. Patients 4-6 received 40 mg/kg i.v. azathioprine over 36 h. Patients 7-9 received 40 mg/kg i.v. azathioprine as three 8-h infusions over 3 days. Clinical remission was defined as steroid withdrawal and an Ulcerative Colitis Disease Activity Index score of 0. The Inflammatory Bowel Disease Questionnaire was obtained at each visit. White blood cell concentrations and erythrocyte concentrations of 6-thioguanine were obtained.

RESULTS

Five of nine patients (56%) had a response and avoided colectomy. Three of nine patients (33%) met the definition for clinical remission. Response was seen within 4 wk. The mean 6-thioguanine concentration for those five patients at 12 wk after infusion was 148.2 pmol/8 x 10(8). Two patients had transient leukopenia and one had transient hepatotoxicity.

CONCLUSIONS

Intravenous azathioprine appears to be safe and of clinical benefit in inducing response and avoiding colectomy in severe steroid refractory ulcerative colitis. Data from an i.v. azathioprine trial in Crohn's disease suggests oral dosing alone may obtain the same results. The role of oral dosing alone in severe ulcerative colitis and the role of azathioprine metabolite levels in monitoring efficacy should be investigated further.

The evolution of mutation rates: separating causes from consequences

Natural selection can adjust the rate of mutation in a population by acting on allelic variation affecting processes of DNA replication and repair. Because mutation is the ultimate source of the genetic variation required for adaptation, it can be appealing to suppose that the genomic mutation rate is adjusted to a level that best promotes adaptation. Most mutations with phenotypic effects are harmful, however, and thus there is relentless selection within populations for lower genomic mutation rates. Selection on beneficial mutations can counter this effect by favoring alleles that raise the mutation rate, but the effect of beneficial mutations on the genomic mutation rate is extremely sensitive to recombination and is unlikely to be important in sexual populations. In contrast, high genomic mutation rates can evolve in asexual populations under the influence of beneficial mutations, but this phenomenon is probably of limited adaptive significance and represents, at best, a temporary reprieve from the continual selection pressure to reduce mutation. The physiological cost of reducing mutation below the low level observed in most populations may be the most important factor in setting the genomic mutation rate in sexual and asexual systems, regardless of the benefits of mutation in producing new adaptive variation. Maintenance of mutation rates higher than the minimum set by this "cost of fidelity" is likely only under special circumstances.

Listeners as co-narrators

A collaborative theory of narrative story-telling was tested in two experiments that examined what listeners do and their effect on the narrator. In 63 unacquainted dyads (81 women and 45 men), a narrator told his or her own close-call story. The listeners made 2 different kinds of listener responses: Generic responses included nodding and vocalizations such as "mhm." Specific responses, such as wincing or exclaiming, were tightly connected to (and served to illustrate) what the narrator was saying at the moment. In experimental conditions that distracted listeners from the narrative content, listeners made fewer responses, especially specific ones, and the narrators also told their stories significantly less well, particularly at what should have been the dramatic ending. Thus, listeners were co-narrators both through their own specific responses, which helped illustrate the story, and in their apparent effect on the narrator's performance. The results demonstrate the importance of moment-by-moment collaboration in face-to-face dialogue.

Gay and lesbian couples in therapy: perspectives for the contemporary family therapist

This paper outlines the major concerns of gay and lesbian couples who seek therapy. Presenting problems are classified as either internal to the relationship or as external (contextual) ones that reflect the influence of oppressive cultural and gender biases. Throughout the article, distinctive therapy methods are described that address the unique concerns of lesbian and gay couples, with special sensitivity to heterosexist and homophobic bias.

Cytotoxic clerodane diterpene esters from Laetia corymbulosa

Three cytotoxic clerodane diterpene esters, corymbulosins A-C, were isolated from an organic extract of the fruit of Laetia corymbulosa (Flacourtiaceae) from Peru. The structures were determined by spectroscopic methods as clerodane diterpenes unsaturated at C-3, C-13(16) and C-14. Corymbulosin A was esterified at C-2 with a decadienoate moiety, while corymbulosins B and C were C-2 epimers esterified at C-6 with a decanoate moiety.

A comprehensive interactive competency program. Part I: Development and framework

The department of medicine/oncology nursing of an academic medical center developed and implemented a comprehensive interactive competency program. The program proved to be valuable to nurses and the organization. Part I of this two-part series describes the process of program development and the resulting framework.

Functional health pattern assessment on-line. Lessons learned

Assessment of patient care needs is the foundation for planning patient care and documenting the nursing process to enhance the nurse's ability to coordinate care, plan discharges effectively, and provide appropriate patient/family education. An on-line assessment module in the hospital clinical information system was implemented. This module uses Gordon's Functional Health Pattern Assessment as the foundation for the professional nursing documentation system in this academic, health science center. The article provides a description of the design of the pathways for the on-line assessment, analysis of the design, benefits of using the on-line assessment, and lessons learned from the design and implementation of the pathways.

Oral paclitaxel and concurrent cyclosporin A: targeting clinically relevant systemic exposure to paclitaxel

Oral paclitaxel is not inherently bioavailable because of the overexpression of P-glycoprotein by intestinal cells and the significant first-pass extraction by cytochrome P450-dependent processes. This study sought to simulate the toxicological and pharmacological profile of a clinically relevant schedule of paclitaxel administered on clinically relevant i.v. dosing schedules in patients with advanced solid malignancies using oral paclitaxel administered with cyclosporin A, an inhibitor of both P-glycoprotein and P450 CYP3A. Nine patients were treated with a single course of oral paclitaxel in its parenteral formulation at a paclitaxel dose level of 180, 360, or 540 mg. Cyclosporin A was administered at a dose of 5 mg/kg p.o. 1 h before and concurrently with oral paclitaxel. Blood sampling was performed to evaluate the pharmacokinetics of paclitaxel, 6-alpha-hydroxypaclitaxel, 3-p-hydroxypaclitaxel, and cyclosporin A. The pharmacokinetic behavior of paclitaxel was characterized using both compartmental and noncompartmental methods. Model-estimated parameters were used to simulate paclitaxel concentrations after once daily and twice daily oral administration of paclitaxel and cyclosporin A. Aside from an unpleasant taste, the oral regimen was well tolerated, and there were no grade 3 or 4 drug-related toxicities. The systemic exposure to paclitaxel, as assessed by maximum plasma concentration (Cmax) and area under the plasma concentration versus time curve (AUC) values, did not increase as the dose of paclitaxel was increased from 180 to 540 mg, and there was substantial interindividual variability (4-6-fold) at each dose level. Mean paclitaxel Cmax values approached plasma concentrations achieved with clinically relevant parenteral dose schedules, averaging 268+/-164 ng/ml. AUC values averaged 3306+/-1977 ng x h/ ml, which was significantly lower than AUC values achieved with clinically relevant i.v. paclitaxel dose schedules. However, computer simulations using pharmacokinetic parameters derived from the present study demonstrated that pharmacodynamically relevant steady-state plasma paclitaxel concentrations of at least 0.06 microM would be achieved after protracted once daily and twice daily dosing with oral paclitaxel and cyclosporin A. Paclitaxel metabolites were detectable in three patients, and the 6-alpha-hydroxypaclitaxel: paclitaxel and 3-p-hydroxypaclitaxel:paclitaxel AUC ratios averaged 0.63 and 0.86, respectively; these values were substantially higher than values reported in patients treated with i.v. paclitaxel. Oral paclitaxel was bioavailable in humans when administered in combination with oral cyclosporin A 5 mg/kg 1 h before and concurrently with paclitaxel treatment, and plasma paclitaxel concentrations achieved with this schedule were biologically relevant and approached concentrations attained with clinically relevant parenteral dose schedules. However, treatment of patients with oral paclitaxel using a single oral dose administration schedule failed to achieve sufficiently high systemic drug exposure and pharmacodynamic effects. In contrast, computer simulations demonstrated that clinically relevant pharmacodynamic effects are likely to be achieved with multiple once daily and twice daily oral paclitaxel-cyclosporin A dosing schedules.

Prediction of hourly microenvironmental concentrations of fine particles based on measurements obtained from the Baltimore scripted activity study

Researchers have developed a variety of computer-based models to estimate population exposure to air pollution. These models typically estimate exposures by simulating the movement of specific population groups through defined microenvironments. During the summer of 1998 and winter of 1999, researchers with the Harvard School of Public Health (HSPH) conducted a field study in Baltimore, MD, to acquire data for improving microenvironmental models. Using a special roll-around instrument system, a technician measured 1- and 12-h pollutant concentrations while engaging in scripted sequences of activities typical of retirees. Each scripted activity assigned the technician to a geographic location and to a microenvironment. The technician recorded special conditions associated with each activity (e.g., open windows, environmental tobacco smoke) in a real-time diary. Data on ambient pollutant levels, temperature, and other potential explanatory factors were also collected. Eleven pollutants were measured by the roll-around instrument system, including particulate matter with an aerodynamic diameter less than 2.5 microm (PM2.5), ozone, carbon monoxide, and benzene. This article presents the results of statistical analyses performed solely on the 1-h PM2.5 data measured by a DustTrak monitor, which ranged from 1.5 to 444.8 microg/m3 with a median value of 14.6 microg/m3. Results of stepwise linear regression (SLR) suggest that PM2.5 exposure is significantly increased by passive smoking, high ambient PM2.5 concentrations reported by fixed-site monitors, food preparation, charcoal grills, car travel, outdoor roadside locations, and high humidity. Analysts should explicitly represent the effects of these parameters within any model developed to estimate population exposure to PM2.5. In a related study, a panel of volunteer retirees each carried a personal PM2.5 monitor and a real-time diary for nominal 24-h sampling periods as they engaged in normal daily activities. A regression equation derived from SLR analysis of the scripted activity database was applied to eight subject-days of diary data provided by the volunteer seniors to produce estimates of PM2.5 exposure for each event documented in each diary. The event-specific exposure estimates were then averaged over all events in each sampling period to produce nominal 24-h average exposure estimates. The absolute difference between the estimate obtained from the regression equation and the corresponding personal monitor measurement averaged 13%. The fixed-site monitors generally provided poorer estimates of exposure; the absolute differences for the Old Town and Clifton Park monitors averaged 26.7% and 19.5%, respectively, of the personal monitor values.

TA90-IC, a new marker for advanced colon cancer

BACKGROUND

Although carcinoembryonic antigen (CEA) is the most frequently used marker for colon cancer, it is elevated in only 70% of patients with advanced disease and in even fewer patients with earlier stages of disease. We previously identified a 90-kDa glycoprotein, TA90, which is present in serum in the form of circulating immune complexes. TA90 is found in a variety of solid neoplasms but rarely in healthy controls (3.2%). We hypothesized that this new tumor-associated antigen may be a useful marker for colon cancer.

METHODS

Serum samples from 59 patients with known colon adenocarcinoma were analyzed for the presence of CEA and TA90. Fifty-one (86%) patients had distant metastases; the remaining patients had clinically localized primary colon cancer. A murine monoclonal antibody-based enzyme-linked immunosorbent assay was used to measure concentrations of TA90-specific circulating immune complexes (TA90-IC). A positive value was defined as an optical density of more than 0.410 at 405 nm. Forty-seven (80%) of the 59 patients had serum samples for TA90 and CEA drawn at the same time.

RESULTS

TA90-IC concentrations were elevated more frequently than CEA concentrations (82.9% vs. 70.2%; P = .134). The combination of both markers identified more patients with colon carcinoma than did either marker alone (93.6%; P < .001).

CONCLUSIONS

Concomitant use of TA90-IC and CEA identified 93.6% of patients with advanced colon cancer. The role of TA90-IC in screening and monitoring progression of earlier disease deserves further investigation.

Substituted benzamide inhibitors of human rhinovirus 3C protease: structure-based design, synthesis, and biological evaluation

A series of nonpeptide benzamide-containing inhibitors of human rhinovirus (HRV) 3C protease was identified using structure-based design. The design, synthesis, and biological evaluation of these inhibitors are reported. A Michael acceptor was combined with a benzamide core mimicking the P1 recognition element of the natural 3CP substrate. alpha,beta-Unsaturated cinnamate esters irreversibly inhibited the 3CP and displayed antiviral activity (EC(50) 0.60 microM, HRV-16 infected H1-HeLa cells). On the basis of cocrystal structure information, a library of substituted benzamide derivatives was prepared using parallel synthesis on solid support. A 1.9 A cocrystal structure of a benzamide inhibitor in complex with the 3CP revealed a binding mode similar to that initially modeled wherein covalent attachment of the nucleophilic cysteine residue is observed. Unsaturated ketones displayed potent reversible inhibition but were inactive in the cellular antiviral assay and were found to react with nucleophilic thiols such as DTT.

Continuous pH and Pco2 monitoring during respiratory failure in children with the Paratrend 7 inserted into the peripheral venous system

CONTEXT

The Paratrend monitor provides continuous arterial blood gas monitoring after insertion through a >/=20-gauge arterial cannula.

OBJECTIVE

To determine the correlation of arterial blood gas values and the Paratrend monitor placed through a peripheral intravenous catheter.

DESIGN

Prospective, open-label evaluation.

SETTING

University-based pediatric intensive care unit.

PATIENTS

Infants and children with respiratory failure and arterial access.

RESULTS

The cohort included 23 infants and children. A total of 100 sample sets (Paratrend/ABG Pco(2) and pH values) were collected. The absolute difference between the arterial and Paratrend Pco(2) was 2. 9 +/- 1.8 mm Hg (range 0 to 9 mm Hg). Linear regression analysis of Paratrend Pco(2) versus arterial Pco(2) resulted in r = 0.97 and r(2) = 0.9479 (P <.001). Bland-Altman analysis of Pco(2) values demonstrated a bias +/- precision of -2.1 +/- 2.7 mm Hg. The absolute difference between arterial and Paratrend pH was 0.04 +/- 0. 02 units (range 0 to 0.15 units). Linear regression analysis of Paratrend pH versus arterial pH resulted in r = 0.83 and r(2) = 0. 7016 (P <.0001). Bland-Altman analysis of pH values revealed a bias +/- precision of 0.03 +/- 0.03 units.

CONCLUSIONS

Inserted through a peripheral intravenous cannula, the Paratrend monitor can be used to provide an accurate estimation of arterial blood gas values in children with respiratory failure.

Novel cytotoxic diterpenes from Casearia arborea

Cytotoxicity-guided fractionation of the dichloromethane-methanol extract of the roots of Casearia arborea yielded five novel clerodane diterpenes, casearborins A-E (1-5), as well as cucurbitacin B. The presence of cucurbitacins glycosides was also detected. The absolute configuration of casearborin E was determined by X-ray crystallography.

Socioeconomic status and the expectation of disability in old age: estimates for England

OBJECTIVES

The longer life expectancy in old age of more privileged socioeconomic groups is well established, but less clear is whether the net effect of additional years of life is a lengthened, stable or reduced duration of disability. Estimates of healthy and disabled life expectancy (using definitions including dependency in activities of daily living and cognitive impairment) were made, contrasting occupational classes I and II (professional and managerial) with the rest.

DESIGN

Disability prevalence was estimated from the Medical Research Council Cognitive Function and Ageing study. Sullivan's method was used to calculate health expectancy.

SUBJECTS

10,377 people aged 65 years or over in Cambridgeshire, Newcastle, Nottingham and Oxford. Subjects were classified as disabled if they had evidence of dementia (using the Automated Geriatric Examination Computer Assisted Taxonomy) or scored 11 or more on the modified Townsend Disability scale, at baseline screen.

RESULTS

The prevalence of disability overall and need for "constant care" was lower in both men and women in social classes I and II compared with the rest. Men aged 65 to 69 in classes I and II can expect nearly 14 years of life free of disability compared with 11.5 years for those in classes III to V: for women the equivalent expectations are 15.5 and 13.8 years. Men aged 65 to 69 in classes I and II can also expect a shorter duration of disability: 1 year compared with 1.6 years for classes III to V. In women expectation of disability is higher overall, but shows little difference by occupational class.

CONCLUSIONS

Relatively privileged socioeconomic groups in England, especially men, can expect fewer years of disability despite longer overall life expectancy. These findings lend weight to optimistic scenarios for the future numbers of older people with disability.