Transgenic Leishmania and the immune response to infection

Genetic manipulation of single-celled organisms such as the Leishmania parasite enables in depth analysis of the consequences of genotypic change on biological function. In probing the immune responses to infection, use of transgenic Leishmania has the potential to unravel both the contribution of the parasite to the infection process and the cellular interactions and mechanisms that characterize the innate and adaptive immune responses of the host. Here, we briefly review recent technical advances in parasite genetics and explore how these methods are being used to investigate parasite virulence factors, elucidate immune regulatory mechanisms and contribute to the development of novel therapeutics for the leishmaniases. Recent developments in imaging technology, such as bioluminescence and intravital imaging, combined with parasite transfection with fluorescent or enzyme-encoding marker genes, provides a rich opportunity for novel assessment of intimate, real-time host-parasite interactions at a previously unexplored level. Further advances in transgenic technology, such as the introduction of robust inducible gene cassettes for expression in intracellular parasite stages or the development of RNA interference methods for down-regulation of parasite gene expression in the host, will further advance our ability to probe host-parasite interactions and unravel disease-promoting mechanisms in the leishmaniases.

Phase I study of vorinostat, a histone deacetylase (HDAC) inhibitor, in combination with carboplatin (Cb) and paclitaxel (P) for patients with advanced solid malignancies (NCI #6922)

2077

Background: Vorinostat (SAHA) induces differentiation & growth arrest in a variety of human carcinoma cell lines by inhibiting HDAC. It also enhances the efficacy of chemotherapy. We are conducting a phase I study to evaluate the combination of vorinostat, Cb & P for patients with advanced solid malignancies. Methods: Patients with advanced solid malignancies who were candidates for combination therapy with Cb & P were eligible. Vorinostat was given orally on d 1–14 of each 21-d-cycle, except in cycle 1 when begun on d -4 to facilitate PK studies. Cb & P were given on d 1 of each cycle. Plasma concentrations of vorinostat, & its 2 major metabolites were quantitated with a novel LC-MS/MS assay. Results: Dose level 4 has been determined as the recommended phase II dose (RP2D) for the combination, since the RP2D of single agent vorinostat is 400 mg on this schedule. Observed toxicities included nausea, vomiting, neutropenia & thrombocytopenia, none of which were dose-limiting. Of 9 patients evaluable for response, 4 had PR (1 head & neck cancer, 3 non-small cell lung cancer), & 2 had stable disease. Vorinostat was rapidly absorbed & AUC increased with dose. Vorinostat PK parameters included Tmax 0.5–2 h, t1/2 1.6 ± 0.5 h, & CL/F 5.8 ± 1.7 l/min. Cb & P did not alter vorinostat PK. 4-Anilino-4-oxobutanoic acid was the major, & long-lived, vorinostat metabolite, with Cmax 1.5–7 fold > vorinostat Cmax & t ½ ∼6h. Vorinostat glucuronide Cmax was 1–5 fold > vorinostat Cmax & glucuronide t ½ ∼2h. The RP2D cohort is being expanded to 12 patients to obtain additional clinical & PK data. Conclusions: Vorinostat can be safely administered in combination with Cb & P at their recommended doses. Vorinostat PK are not altered by Cb & P. Promising anti-cancer activity has been noted in patients with advanced NSCLC. Support: U01CA099168–01, U01CA62505, NIH/NCCR/GCRC grant 5M01RR 00056.

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No significant financial relationships to disclose.

Total blockade of the epidermal growth factor receptor with the combination of cetuximab and gefitinib: A phase I study for patients with recurrent non-small cell lung cancer (NSCLC)

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Background: Cetuximab and gefitinib inhibit the epidermal growth factor receptor (EGFR) through different mechanisms. Preclinical evidence suggests that the combination of cetuximab and Gefitinib is synergistic and has shown antitumor activity in vitro and in xenografts (Matar et al, Clin Cancer Res, 2004). We are conducting a phase I study to determine the doses of the two agents that can be administered in combination. Methods: Patients (pts) with advanced NSCLC were eligible upon progression following 1 or 2 prior chemotherapy regimens. Gefitinib was administered at a dose of 250 mg/day for all cohorts. The dose of cetuximab was escalated in sequential cohorts of patients ( table ) and there will be no dose escalation above the approved doses for both agents (dose level 3). Paraffin-embedded tissue samples of the primary cancer were collected from all patients for analysis of EGFR mutations, gene amplification and protein expression. Results: From March to December 2005, 11 patients have been entered to the 3 planned cohorts. Patient characteristics include: 3 women and 8 men, with a median age of 63 years (range 51–77) and ECOG performance status (PS) of: 0 = 50%, 1 = 50%. A total of 26 treatment cycles were administered to the 11 pts with a median of 2 cycles per pt (range 1–8). Other observed adverse events include grade 1/2 skin rash and diarrhea. Of 8 evaluable patients, 4 had stable disease. No DLT has been experienced so far at the projected recommended phase 2 dose (dose level 3). The results of correlative studies will be presented at the meeting. Conclusions: The novel combination of cetuximab and gefitinib is safe and is associated with promising anti-cancer activity in recurrent NSCLC.

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The impact of ward design on the behaviour, occupational satisfaction and well-being of psychiatric nurses

Studies have shown that modifications to the physical environment of psychiatric institutions are associated with positive changes in patients' behaviour, attitudes and perceptions. However, little attention has been paid to the impact such modifications to the physical environment have on the nursing staff. The building of two completely new wards at a rural psychiatric hospital provided an opportunity to examine this issue. Measures of the nursing staffs' observed behaviour and self-ratings of burnout and job satisfaction were obtained in both the old and the new wards. The results showed that the new wards were associated with largely positive changes in behaviour and increased burnout, but there was no change in job satisfaction. However, it was clear that a vital component in the success of any environmental manipulation is an appropriate, corresponding change in the organizational climate.

Temporal changes in reproductive hormones and conceptus-endometrial interactions during embryonic diapause and reactivation of the blastocyst in European roe deer (Capreolus capreolus)

The roe deer blastocyst is in diapause between August and December, after which time it expands and elongates rapidly before implantation. Blood samples were taken from 30 animals to define temporal changes in reproductively important hormones to investigate the physiological cues present at embryo reactivation. In 15 of these animals, changes in uterine and conceptus protein synthesis and secretion, and luteal progesterone release during diapause and reactivation, were assessed after culture of these tissues in vitro. Oestradiol concentrations remained low during diapause (1.07 +/- 0.4 pg ml(-1)) and expansion (1.2 +/- 0.4 pg ml(-1)) but increased by 30 times at trophoblast elongation (49.17 +/- 0.37 pg ml(-1)). Prolactin remained at basal concentrations (4.69 +/- 0.86 ng ml(-1)) and increased after implantation (12.34 +/- 2.71 ng ml(-1)). Peripheral progesterone concentrations and luteal progesterone release remained constant throughout diapause, reactivation and implantation (peripheral progesterone: 3.82 +/- 1.97 ng ml(-1); luteal progesterone: 6.72 +/- 0.81 ng mg(-1) protein). Incorporation of a radiolabel into conceptus secretory proteins increased by four times at expansion compared with diapause, whereas incorporation into endometrial secretions remained constant. At elongation, incorporation into endometrial secretions increased two times and conceptus secretions increased 32 times. Two-dimensional electrophoresis and fluorography showed that the profile of endometrial secretory proteins was constant until implantation when qualitative changes were evident. Although a role for an endocrine maternal trigger of reactivation from diapause cannot be dismissed, these data provide no supporting evidence and indicate that the conceptus itself may drive reactivation.

Temporal changes in reproductive hormones and conceptus-endometrial interactions during embryonic diapause and reactivation of the blastocyst in European roe deer (Capreolus capreolus)

The roe deer blastocyst is in diapause between August and December, after which time it expands and elongates rapidly before implantation. Blood samples were taken from 30 animals to define temporal changes in reproductively important hormones to investigate the physiological cues present at embryo reactivation. In 15 of these animals, changes in uterine and conceptus protein synthesis and secretion, and luteal progesterone release during diapause and reactivation, were assessed after culture of these tissues in vitro. Oestradiol concentrations remained low during diapause (1.07 +/- 0.4 pg ml(-1)) and expansion (1.2 +/- 0.4 pg ml(-1)) but increased by 30 times at trophoblast elongation (49.17 +/- 0.37 pg ml(-1)). Prolactin remained at basal concentrations (4.69 +/- 0.86 ng ml(-1)) and increased after implantation (12.34 +/- 2.71 ng ml(-1)). Peripheral progesterone concentrations and luteal progesterone release remained constant throughout diapause, reactivation and implantation (peripheral progesterone: 3.82 +/- 1.97 ng ml(-1); luteal progesterone: 6.72 +/- 0.81 ng mg(-1) protein). Incorporation of a radiolabel into conceptus secretory proteins increased by four times at expansion compared with diapause, whereas incorporation into endometrial secretions remained constant. At elongation, incorporation into endometrial secretions increased two times and conceptus secretions increased 32 times. Two-dimensional electrophoresis and fluorography showed that the profile of endometrial secretory proteins was constant until implantation when qualitative changes were evident. Although a role for an endocrine maternal trigger of reactivation from diapause cannot be dismissed, these data provide no supporting evidence and indicate that the conceptus itself may drive reactivation.

Effects of pre- and post-mating feed intake on blastocyst size, secretory function and glucose metabolism in meishan gilts

This experiment was designed to determine the effects of a nutritional regime, known to increase embryo survival, on blastocyst development and function. Day 12 blastocysts were recovered from Meishan gilts allocated in a 2x2 factorial design to receive either a high or a maintenance diet before or after mating (n = 4-6 gilts per group). The post-mating diet had no effect on individual blastocyst size, cell number, secretion of oestradiol-17beta or retinol binding protein, glucose metabolism or on the within-litter variability in these measures. Blastocysts recovered from gilts consuming the high pre-mating diet had more cells (13.501 v. 13.006 log cells; SED = 0.23; P = 0.05), greater production of CO2 from glucose (2.19 v. 1.23 log pmol(-1) blastocyst(-1) 3 h(-1), SED = 0.42; P = 0.05) and a lower within-litter standard deviation in blastocyst surface area (0.66 v. 1.18 log mm2, SED = 0.24; P = 0.04) compared with gilts fed the maintenance pre-mating diet. Collectively, these data suggest that a nutritional strategy that increases embryo survival is also associated with an increase in individual blastocyst cell number and reduced within-litter variability in blastocyst size.

Effects of pre- and post-mating nutritional status on hepatic function, progesterone concentration, uterine protein secretion and embryo survival in Meishan pigs

This experiment examined whether the pre- or the post-mating diet had greater impact on embryo survival in Meishan gilts. Gilts received either a maintenance (1.15 kg day(-1); n = 12) or a high (3.5 kg day(-1); n = 12) diet during the oestrous cycle preceding mating. After mating, half the animals in each group received either the maintenance or the high diet until slaughter on Day 12. Gilts fed the high pre-mating diet had more corpora lutea (22.7 v. 19.0, SED = 0.98; P<0.001), increased embryo survival (95.5% v. 74.8%, SED = 7.58; P<0.01) and heavier corpora lutea (-0.71 log g v. -0.90 log g, SED = 0.09; P = 0.07) compared with gilts fed the maintenance diet prior to mating. The post-mating diet had no effect on embryo survival. There were no treatment effects on blastocyst developmental stage, luteal surface area or progesterone release. Gilts receiving the high post-mating diet had heavier livers than those fed the maintenance post-mating diet (1.45 v 1.08% of total bodyweight, SED = 0.07; P<0.001), suggesting that these gilts have a greater capacity to metabolize progesterone. Pre-mating nutritional status therefore appears to be a greater determinant of embryo numbers and survival than the post-mating diet.

The quality of psychiatric nurses' interactions with patients: an observational study

The behaviour of nursing staff in each ward of a psychiatric hospital was observed at 5-min intervals for between 7 and 10 h per day for 10 days. The nurses' behaviour was equally divided between interacting with patients, interacting with staff, solitary task oriented behaviour and other behaviours. There was less staff-patient interaction in the acute ward than in the long-term and psychogeriatric wards and senior nurses interacted less with patients and engaged in more solitary task oriented behaviour. Of the interactions with patients, almost 25% were rated as positive and only 0.3% negative. In the long-term wards almost 47% of the interactions were positive.