A novel psychosocial virtual reality intervention (BMT-VR) for patients undergoing hematopoietic stem cell transplantation: Pilot randomized clinical trial design and methods

BACKGROUND

Although patients undergoing hematopoietic stem cell transplantation (HSCT) must cope with psychological distress and isolation during an extended transplant hospitalization, psychosocial interventions to address these unmet needs are lacking. Virtual reality offers an innovative modality to deliver a patient-centered psychosocial intervention to address psychosocial needs of patients undergoing HSCT. However, there are currently no supportive care interventions leveraging virtual reality in patients undergoing HSCT.

OBJECTIVE

To describe the methods of a randomized clinical trial (RCT) to assess the feasibility and preliminary efficacy of a self-administered, virtual reality-delivered psychosocial intervention (BMT-VR) to improve psychological distress and quality of life (QOL) for patients hospitalized for HSCT.

METHODS

This study entails a single-center RCT of BMT-VR compared to usual transplant care in 80 patients hospitalized for HSCT. Adult patients with hematologic malignancies hospitalized for autologous or allogeneic HSCT are eligible. BMT-VR includes psychoeducation about the HSCT process, psychosocial skill building to promote effective coping and acceptance, and self-care and positive psychology skills to promote post-HSCT recovery. The primary aim is to assess the feasibility defined a priori as ≥60% of eligible patients enrolling in the study, and of those enrolled and randomized to the BMT-VR, ≥ 60% completing 4/6 BMT-VR modules. Secondary objectives include assessing the preliminary effects on psychological distress and QOL.

DISCUSSION

This is the first RCT of a virtual reality-delivered psychosocial intervention for the HSCT population. If deemed feasible, a future larger multi-site clinical trial can evaluate the efficacy of BMT-VR on outcomes for patients hospitalized for HSCT.

Outcomes of a Formal Hematopoietic Cell Transplantation Survivorship Program on Screening for Late Effects

Allogeneic hematopoietic cell transplantation (HCT) survivors may benefit from routine screening for post-transplant complications. However, the impact of formal survivorship efforts to promote screening adherence is uncertain. The effect of a formal HCT survivorship program to promote screening adherence was evaluated. We conducted a retrospective analysis of an academic formal HCT survivorship program with primary and specialty consult components. We included patients who underwent allogeneic HCT and were alive and relapse-free 1-year post-HCT. We excluded patients who died <2-year post-HCT or transferred care. We measured screening adherence to cardiovascular, pulmonary, ocular, secondary cancer, and endocrine evaluations. The primary outcome was proportion of patients completing ≥1 evaluation per screening domain prior to 2-year post-HCT. We examined screening adherence during 3 time periods: presurvivorship (2012 to 2014) and 2 postsurvivorship (2016 to 2018 and 2019 to 2021) using multivariate logistic and Cox proportional hazards regression. Four hundred ten patients (2012 to 2014: n = 136, 2016 to 2018: n = 153, 2019 to 2021: n = 121) were included. Compared to the presurvivorship period (16.9%), patients in 2016 to 2018 (47.7%, odds ratio [OR] = 4.9, P < .0001) and 2019 to 2021 (34.7%, OR = 2.7, P = .001) were more likely to complete ≥1 evaluation per screening domain. Except for pulmonary function tests in 2019 to 2021, median time to completion of survivorship evaluations was shorter in the survivorship periods compared to presurvivorship. Patients who completed a formal HCT survivorship consult in 2016 to 2018 and 2019 to 2021 were more likely to complete ≥1 evaluation per screening domain (OR = 5.1, P = .0004). Survivorship consult had similar effect on the primary screening outcome in 2016 to 2018 and 2019 to 2021 (consult × time interaction OR: 2.5, P = .2). However, patients who received a consult in 2019 to 2021 were more likely to complete all screenings (consult × time interaction: OR = 5.7, P = .03). Our HCT survivorship program with primary and specialty components improved screening adherence. Additional studies are needed to evaluate efficacy, dissemination, and implementation of formal HCT survivorship programs.

Improving the solubility of pseudo-hydrophobic Alzheimer's Disease medicinal chemicals through co-crystal formulation

Natural products are ligands and potential inhibitors of Alzheimer's disease (AD) tau. Dihydromyricetin (DHM) is a CNS active natural product. Despite having signature polyphenolic character, DHM is ostensibly hydrophobic owing to intermolecular hydrogen bonds that shield hydrophilic phenols. Our research shows DHM becomes ionized at near-neutral pH allowing formulation of salts with transformed solubility. The MicroED co-crystal structure with trolamine reveals DHM salts as metastable solids with unlocked hydrogen bonding and a thermodynamic bent to solubilize in water. All salt formulations show better inhibitory activity against AD tau than the non-salt form, with efficacies correlating to enhanced solubilities. These results underscore the role of structural chemistry in guiding selection of solubilizing agents for chemical formulation. We propose DHM salts are appropriate formulations for research as dietary supplements to promote healthy aging by combating protein misfolding. Additionally, DHM is a suitable lead for medicinal chemistry and possible development of CNS pharmaceuticals.

Starting the fight in the tumor: expert recommendations for the development of human intratumoral immunotherapy (HIT-IT)

A European Society for Medical Oncology (ESMO)-sponsored expert meeting was held in Paris on 8 March 2018 which comprised 11 experts from academia, 11 experts from the pharmaceutical industry and 2 clinicians who were representatives of ESMO. The focus of the meeting was exclusively on the intratumoral injection/delivery of immunostimulatory agents with the aim of harmonizing the standard terms and methodologies used in the reporting of human intratumoral immunotherapy (HIT-IT) clinical trials to ensure quality assurance and avoid a blurring of the data reported from different studies. The goal was to provide a reference document, endorsed by the panel members that could provide guidance to clinical investigators, pharmaceutical companies, ethics committees, independent review boards, patient advocates and the regulatory authorities and promote an increase in the number and quality of HIT-IT clinical trials in the future. Particular emphasis was placed not only on the development of precise definitions to facilitate a better understanding between investigators but also on the importance of systematic serial biopsies as a driver for translational research and the need for the recording and reporting of data, to facilitate a better understanding of the key processes involved.

Small-world networks of residue interactions in the Abl kinase complexes with cancer drugs: topology of allosteric communication pathways can determine drug resistance effects

Computational modelling of efficiency and robustness of the residue interaction networks and allosteric pathways in kinase structures can characterize protein kinase sensitivity to drug binding and drug resistance effects.

Regional chemotherapy for unresectable primary liver cancer: results of a phase II clinical trial and assessment of DCE-MRI as a biomarker of survival

BACKGROUND

This study reports the results of hepatic arterial infusion (HAI) with floxuridine (FUDR) and dexamethasone (dex) in patients with unresectable intrahepatic cholangiocarcinoma (ICC) or hepatocellular carcinoma (HCC) and investigates dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) assessment of tumor vascularity as a biomarker of outcome.

PATIENTS AND METHODS

Thirty-four unresectable patients (26 ICC and eight HCC) were treated with HAI FUDR/dex. Radiologic dynamic and pharmacokinetic parameters related to tumor perfusion were analyzed and correlated with response and survival.

RESULTS

Partial responses were seen in 16 patients (47.1%); time to progression and response duration were 7.4 and 11.9 months, respectively. Median follow-up and median survival were 35 and 29.5 months, respectively; 2-year survival was 67%. DCE-MRI data showed that patients with pretreatment integrated area under the concentration curve of gadolinium contrast over 180 s (AUC 180) >34.2 mM.s had a longer median survival than those with AUC 180 <34 mM.s (35.1 versus 19.1 months, P = 0.002). Decreased volume transfer exchange between the vascular space and extracellular extravascular space (-DeltaK(trans)) and the corresponding rate constant (-Deltak(ep)) on the first post-treatment scan both predicted survival.

CONCLUSIONS

In patients with unresectable primary liver cancer, HAI therapy can be effective and safe. Pretreatment and early post-treatment changes in tumor perfusion characteristics may predict treatment outcome.

Analysis of survival with modified docetaxel, cisplatin, fluorouracil (mDCF), and bevacizumab (BEV) in patients with metastatic gastroesophageal (GE) adenocarcinoma: Results of a phase II clinical trial

4512

Background: Metastatic GE cancer is an aggressive disease with poor patient (pt) outcomes. Despite response rates of 30–60% to combination chemotherapy, response duration is usually 4–6 mo and 24-mo survival is 5–10%. The addition of BEV to chemotherapy has improved survival in several solid tumors, and has demonstrated encouraging activity in GE cancer (Shah et al, JCO 2006). We report mature tolerability and efficacy results of mDCF+BEV in GE cancer, with an emphasis on prolonged pt survival. Methods: Previously untreated metastatic GE pts with adequate end organ function received BEV 10mg/kg, Docetaxel 40mg/m2, FU 400mg/m2, Leucovorin 400mg/m2 on day 1, FU 1000 mg/m2/day x 2 days IVCI, and Cisplatin 40mg/m2 on day 3. Treatment is repeated every 14 days without prophylactic growth factor support. The primary objective is to improve 6-month progression free survival (PFS) from 43% (historical DCF control) to 63% with the addition of BEV. Target accrual is 44 evaluable pts, with 10% type I & II error. Secondary objectives include tolerability, response rates (RECIST), median PFS, 12-mo survival, and overall survival (OS). Results: Pt enrollment has completed: median age 57(range 29–74), median KPS 80% (70–100), M:F 32:12, gastric/GEJ/esophagus 22:17:5. In 39 patients with measurable disease we observed 26 confirmed partial responses (67%, 95% CI 50%- 81%), and 12 (31%) stable disease. Six-month PFS is 79% (95% CI 68%-93%), the median PFS is 12 mo (95% CI: 8.8–16). At median follow up of 12.3 mo, median OS is 16.2 mo (95%CI 11.4-infinitiy). 12- and 18-mo OS is 63% (95%CI 44–77%) and 46% (95%CI 27–63%), respectively. Minimal chemotherapy related grade 3–4 adverse events were observed: fatigue (20%), dehydration (13%), mucositis (9%), nausea/vomiting (7%), febrile neutropenia (4%). BEV related adverse event was perforation (n=1) and bleeding (n=1). 31% developed grade 3–4 venous thromboembolism, of which 93% were asymptomatic. No grade 3–4 hypertension, proteinuria or arterial thrombosis was observed. Conclusions: mDCF+BEV appears tolerable and has notable long term pt outcomes: 6-mo PFS is 79% (surpassing our efficacy endpoint), median OS 16.2 mo, and 18-mo OS 46%.

No significant financial relationships to disclose.

Pharmacokinetics (PK) of split-dose flavopiridol (F) administered with CPT-11 (CPT) and cisplatin (Cis)

2578

Background: F, a cyclin-dependent kinase inhibitor, induces tumor lysis in CLL when administered as a 30 mg/m2 loading dose over 0.5h followed by a 30 mg/m2 maintenance dose over 4h (hybrid F; Byrd et al, Blood 2006). F given as a 1h bolus (bolus F) demonstrates promising clinical activity when combined with CPT in solid tumors (Shah et al, CCR 2005). Data suggest that F concentrations of 2–3 μM are required to enhance the effects of CPT in solid tumors (Motwani et al, CCR 2001), but controversy exists over the optimal F schedule for chemotherapy potentiation. Methods: We are conducting a phase I trial of CPT/Cis→F, with F administered on both a bolus F and hybrid F schedule. After identifying the maximum tolerated dose (MTD) of bolus F (CPT/Cis→F 50mg/m2), the hybrid F schedule was examined. The F loading dose was escalated from 20→30mg/m2 and the F maintenance dose escalated from 20→50mg/m2. Plasma samples were obtained from patients (pts) treated with bolus F at the MTD and with hybrid F at all dose levels. To better assess F PK interaction with CPT/Cis, F was given before CPT/Cis on cycle 2 only. Results: Complete PK data are available from 6 pts treated at the bolus F MTD (50 mg/m2) and on 20 pts treated with hybrid F (20→20 mg/m2, 25→25 mg/m2 and 30→30 mg/m2) for cycles 1 and 2. Both bolus F and hybrid F PK are consistent with data previously reported. Although cycle 1 AUCs are similar for bolus F 50 mg/m2 and hybrid F 30→30 mg/m2 (10.47±4.97 vs 10.75±15.14 μM/h, p=NS), the Cmax achieved with bolus F 50 mg/m2 is significantly greater than that achieved with hybrid F 30→30 mg/m2 (2.31±0.65 vs 1.21±0.35 μM, p<0.02). No significant PK differences occurred between cycles 1 and 2. Toxicity was not associated with F Cmax. With CPT/Cis→bolus F, the PR rate was 10/29 (35%) vs 3/33 (9%) with CPT/Cis→hybrid F. Conclusions: The Cmax achieved with bolus F is greater than that achieved with hybrid F, with no increase in toxicity. Additionally, the Cmax achieved with hybrid F does not exceed the 2 μM plasma concentration required for potentiation of chemotherapy-induced apoptosis. The greater number of responses achieved with bolus F suggests that bolus F may be more efficacious than hybrid F when used in combination with CPT for the treatment of solid tumors. (Supported by R01-CA67819)

No significant financial relationships to disclose.

Final results of a multicenter phase II study of irinotecan (CPT), cisplatin (CIS), and bevacizumab (BEV) in patients with metastatic gastric or gastroesophageal (GEJ) adenocarcinoma (NCI #6447)

4020

Background: BEV improves survival in several solid tumors when combined with chemotherapy. CPT/CIS is active in gastric and GEJ cancers with a median time to progression(TTP) of 4.2 months, response rate(RR) of 30%, and median survival of ∼7 months (Pozzo Ann Onc 2004). Anti-angiogenic therapy for upper GI cancers is of concern due to a potential increased risk of perforation or GI bleed. We evaluated the efficacy and safety of the combination of CPT, CIS, and BEV in the treatment of gastric and GEJ cancers. Methods: 47 patients with previously untreated metastatic gastric or GEJ adenocarcinomas were treated with BEV 15mg/kg day 1, CPT 65mg/m2 and CIS 30mg/m2 days 1 and 8, every 21 days. The primary endpoint was TTP, with 90% power to demonstrate a 50% improvement in TTP (eg. from 5 to 7.5 months) over historical control. Safety, response, and survival were secondary endpoints. Results: Patient characteristics: median age 59 (range 25–75), KPS 90% (70%-100%), Male 34, Gastric/GEJ 27:20. With a median follow up of 9.0 months, median TTP is 9.9 months (95%CI: 6.5–11.8 months). In 33 patients with measurable disease, the RR (partial + complete) is 66.7% (95%CI: 51–83%). Median survival is 12.6 months (95%CI: 10.1–17.1 months). We observed no change in expected CPT/CIS related toxicity: eg. grade 3/4 neutropenia (29%), nausea/vomiting (10%), and diarrhea (13%). Possible BEV related toxicity includes 2 gastric perforations, 1 grade 3 peri-rectal fistula, 2 cardiac events(1 ischemia, 1 reduced ejection fraction), and 10 patients with grade 3/4 hypertension. Although the primary tumor was unresected in 35 patients, we observed only 1 patient with an upper GI bleed. Grade 3/4 thromboembolic events occurred in 25%. Conclusions: The combination of CPT/CIS/BEV is active in gastric and GEJ cancers. The toxicity profile is acceptable. The primary endpoint of improving TTP was exceeded by 100% with median TTP 9.9 months. Despite the majority of patients having their primary tumor unresected, GI bleeding was not significant. The thromboembolic and perforation rates with CPT/CIS are similar with or without BEV (Shah et al JCO 2005). Further development of BEV in gastric and GEJ cancers is clearly warranted.

[Table: see text]

Endocytosis in identified rat corticotrophs

1. We used the patch-clamp technique, in conjunction with membrane capacitance measurement, fluorescence measurement of intracellular calcium concentration ([Ca(2+)](i)), and flash photolysis of caged Ca(2+) to study exo- and endocytosis in identified rat corticotrophs. 2. Exocytosis stimulated by depolarization pulses was typically followed by a 'slow' endocytosis that retrieved the membrane with a time constant of approximately 6 s. The efficiency (the endocytosis/exocytosis amplitude ratio) of 'slow' endocytosis was approximately 1.2 at [Ca(2+)](i) < 3 microM and increased to approximately 1.6 at [Ca(2+)](i) > 3 microM. 3. Whole-cell dialysis through a patch pipette did not affect the kinetics and the efficiency of 'slow' endocytosis, but the amplitude of exocytosis was reduced. 4. 'Slow' endocytosis did not require sustained [Ca(2+)](i) elevation and its kinetics was only weakly [Ca(2+)](i) dependent. Our results suggest that 'slow' endocytosis involves a Ca(2+) sensor with a high Ca(2+) affinity (approximately 500 nM). 5. At high [Ca(2+)](i) (> 10 microM), the 'slow' endocytosis was frequently preceded by a 'fast' endocytosis that comprised multiple steps of rapid decrease in membrane capacitance. 6. Neither calmodulin nor calcineurin appeared to be the Ca(2+) sensor for endocytosis because the two forms of endocytosis were not affected by the calmodulin inhibitor calmidazolium (500 microM) or the calcineurin inhibitors cyclosporin A (1 microM) and calcineurin autoinhibitory peptide (1 mg ml(-1)). Ba(2+), a poor activator of calmodulin, could support both forms of endocytosis but slowed the kinetics of 'slow' endocytosis approximately 2-fold. 7. Non-hydrolysable analogues of GTP (GDP-beta-S) and ATP (ATP-gamma-S) also failed to inhibit either form of endocytosis, indicating that neither GTP nor ATP was essential for endocytosis. 8. We suggest that the high Ca(2+) affinity of 'slow' endocytosis may be important for maintaining continuous cycles of exocytosis-endocytosis during sustained adrenocorticotropin secretion in corticotrophs.

Voltage-gated Ca2+ channels and intracellular Ca2+ release regulate exocytosis in identified rat corticotrophs

1. The patch clamp technique was used in conjunction with a fluorescent Ca2+ indicator (indo-1, or indo-1FF) to measure simultaneously cytosolic Ca2+ concentration ([Ca2+]i) and exocytosis (changes in membrane capacitance) in single, identified rat corticotrophs. 2. Exocytosis could be stimulated by extracellular Ca2+ entry (via voltage-gated Ca2+ channels). A train of depolarizations could exhaust the pool of readily releasable granules and the pool replenished with a time constant of 42 s (at 22-25 C). 3. Recordings from cells with 0.5 mM intracellular cAMP showed that the amplitude of the depolarization-triggered exocytosis, the Ca2+ sensitivity of exocytosis, as well as the rate of replenishment of the readily releasable pool, were similar to the controls. 4. Exocytosis could also be stimulated by intracellular Ca2+ release from the inositol 1,4, 5-trisphosphate (IP3)-sensitive store (via flash photolysis of caged IP3). At comparable [Ca2+]i, extracellular Ca2+ entry and intracellular Ca2+ release had similar efficacy in triggering exocytosis. 5. The rate of exocytosis triggered via depolarization or intracellular Ca2+ release was much faster than that triggered via uniform elevation of [Ca2+]i (Ca2+ dialysis or flash photolysis of caged Ca2+). 6. The above findings suggest that both intracellular Ca2+ release and voltage-gated extracellular Ca2+ entry generate a spatial Ca2+ gradient, such that the local [Ca2+] near the exocytic sites was approximately 3-fold higher than the mean cytosolic [Ca2+]. However, neither cAMP nor the spatial Ca2+ gradient generated during depolarization could account for the high efficacy of corticotropin-releasing hormone (CRH) in stimulating adrenocorticotropic hormone (ACTH) secretion from corticotrophs.

Stimulation of Ca(2+)-independent exocytosis in rat pituitary gonadotrophs by G-protein

We employed the whole-cell recording technique in conjunction with fluorometry to measure cytosolic Ca(2+) concentration ([Ca(2+)](i)) and exocytosis (capacitance measurement) in single, identified rat gonadotrophs. Direct activation of G-protein (via intracellular dialysis of non-hydrolysable analogues of GTP, but not of GDP) triggered a slow rise in capacitance even in the presence of a fast intracellular Ca(2+) chelator. The broad-spectrum kinase inhibitors H7 and staurosporine did not prevent this Ca(2+)-independent exocytosis, ruling out the involvement of the cAMP and PKC pathways. AlF(4)(-), a potent stimulator of heterotrimeric G-proteins, failed to stimulate any exocytosis when the intracellular Ca(2+) store was depleted, implicating the involvement of AlF(4)(-)-insensitive G-protein(s). Maximal stimulation of Ca(2+)-independent exocytosis by GTP analogues did not reduce the number of readily releasable granules that were available subsequently for Ca(2+)-dependent release. The last finding raises the possibility that the G-protein-stimulated Ca(2+)-independent exocytosis may regulate a pool of granules that is distinct from the Ca(2+)-dependent pool.

Tissue-specific expression of functional isoforms of mouse folypoly-gamma-glutamae synthetase: a basis for targeting folate antimetabolites

Folates and folate antimetabolites are metabolically trapped in mammalian cells as polyglutamates, a process catalyzed by folylpoly-gamma-glutamate synthetase (FPGS). Using 5'-rapid amplification of cDNA ends, RNase protection assays, transfection of cDNAs into FPGS-deficient cells, and kinetic analysis of recombinant enzymes expressed in insect cells, it was determined that the species of active FPGS in mouse liver and kidney was different from that in mouse tumor cells, bone marrow, and intestine. The NH2-terminal peptide of hepatic enzyme contained 18 amino acids not found in enzyme from dividing tissues, and the specificity of the two isoforms for antifolates also differed, suggesting different architecture of the active sites. In most tissues, the expression of one isozyme or the other was an all-or-nothing event. The exclusive use of one of two alternative sets of initial coding exons in different tissues underlies this phenomenon, suggesting the design of antifolates specific for activation by individual FPGS isoforms and hence tissue-selective targeting of antifolate therapy for cancer, arthritis, or psoriasis.

Regulation of exocytosis via release of Ca(2+) from intracellular stores

The release of Ca(2+) from intracellular stores is an important trigger for secretion in many cell types. Depending on the spatial relationship between the intracellular Ca(2+) stores and the site of exocytosis, the Ca(2+) signal can be very local or spread throughout the entire cell. Here, we review how the release of Ca(2+) from inositol trisphospate (IP(3))-sensitive stores contributes differently to the stimulus-secretion coupling in three types of secretory cells (acinar cells of the pancreas, gonadotrophs, and corticotrophs of the anterior pituitary gland). We propose that in both pancreatic acinar cells and pituitary gonadotrophs the IP(3)-sensitive stores may be in close proximity to the sites of exocytosis such that the concentration of Ca(2+) at these sites are transiently much higher than the average cytosolic Ca(2+) concentration. In contrast, the local Ca(2+) gradient is less prominent in pituitary corticotrophs. Finally, some recent technical developments that may contribute significantly to future investigations of local Ca(2+) signals are discussed.

Alpha-latrotoxin stimulates inward current, rise in cytosolic calcium concentration, and exocytosis in at pituitary gonadotropes

Alpha-latrotoxin (LTX) from the black widow spider venom, stimulates neurotransmitter release from neuronal cells via Ca2+ -dependent as well as Ca2+ -independent mechanisms. In some peptide-secreting endocrine cells, however, LTX stimulates hormone release mainly via a Ca2+ -independent mechanism. Here we investigated the action of LTX in rat pituitary gonadotropes that secrete the peptide, LH. Using the patch-clamp technique in conjunction with the fluorescent Ca2+ indicator (indo-1) to simultaneously measure the cytosolic Ca2+ concentration ([Ca2+]i) and ionic current, we showed that LTX elicited bursts of inward current that were accompanied by [Ca2+]i elevations. In the presence of a physiological concentration of extracellular Ca2+, the unitary conductance of the LTX-induced current was about 300 pS, and only about 6.4% of the current was carried by Ca2+. The LTX-induced current was occasionally followed by intracellular Ca2+ release. At [Ca2+]i of 1 microM or more, exocytosis (detected by membrane capacitance measurement) was consistently triggered, and it was frequently followed by endocytosis. Thus, LTX triggers Ca2+ -dependent exocytosis in gonadotropes via extracellular Ca2+ entry as well as intracellular Ca2+ release. In approximately 25% of the cells, LTX could also trigger a slow exocytosis in the absence of [Ca2+]i elevation. Therefore, LTX has both Ca2+ -dependent and Ca2+ -independent actions in gonadotropes.

A feasibility study of two methods for end-user configuration of a clinical event monitor

We developed and evaluated a feature that allows users to control what types of clinical information are delivered to them. Using a paper or web-based configuration form, users turn individual alerts and sets of results on or off, and set how they are delivered. We used usage rates to evaluate this feature. Of 16 residents who had received clinical information from our clinical event monitor, 4 (25%) made at least one change (range 10-25). Of 41 interns, 5 (12.2%) made at least one change (range 5-91). The difference was borderline significant (p < 0.1). 5/7 web users changed preferences through a dial-up connection from home. More users used the web-based preference form than the paper form. This difference may be due to the better accessibility of the web-based form. A survey established that this feature was not as highly utilized as anticipated partly because the initial (default) preference setting was acceptable and partly because the users were too busy to customize their alert settings. We conclude that user configuration of a system that delivers information using a web-based preference form is feasible and may become important as the volume of information and number of available communication channels increase.

alpha-adrenergic stimulation of cytosolic Ca2+ oscillations and exocytosis in identified rat corticotrophs

1. The patch clamp technique was used in conjunction with a fluorescent Ca2+ indicator (indo-1, or indo-1FF) to measure simultaneously cytosolic Ca2+ concentration ([Ca2+]i), ionic current and changes in membrane capacitance in single rat corticotrophs identified with the reverse haemolytic plaque assay. 2. Application of the adrenocorticotropin (ACTH) secretagogue noradrenaline (NA; norepinephrine), triggered [Ca2+]i oscillation in corticotrophs via alpha-adrenergic receptors and the guanosine trisphosphate (GTP) binding protein-coupled phosphoinositide pathway. 3. Simultaneous measurement of [Ca2+]i and capacitance shows that exocytosis was triggered during the first cycle of NA-induced [Ca2+]i oscillation and the mean increase in cell membrane surface area was 1.4 +/- 0.3 % (n = 6). 4. When Ca2+ was directly released from the inositol 1,4, 5 trisphosphate (IP3)-sensitive store via flash photolysis of caged IP3, the mean increase in cell surface area was 1.5 +/- 0.5 % (n = 6). Thus, NA-stimulated ACTH secretion in rat corticotrophs is closely coupled to intracellular Ca2+ release. 5. Large and rapid elevation of [Ca2+]i (>15 microM) via flash photolysis of caged Ca2+ triggered two phases of exocytosis: a rapid exocytic burst that was complete in approximately 100 ms and a slow burst that continued for many seconds. 6. The rapid exocytic burst reflected the exhaustion of a pool of readily releasable granules and, on average, increased the cell surface by 2.8 +/- 0.1 % (n = 14). 7. We suggest that the relatively weak exocytic response in corticotrophs during intracellular Ca2+ release may be partially attributed to a smaller pool of readily releasable granules.

Mutations in the reduced folate carrier gene which confer dominant resistance to 5,10-dideazatetrahydrofolate

L1210/D3 mouse leukemia cells are resistant to 5, 10-dideazatetrahydrofolate due to expansion of cellular folate pools which block polyglutamation of the drug (Tse, A., and Moran, R. G. (1998) J. Biol. Chem. 273, 25944-25952). These cells were found to have two point mutations in the reduced folate carrier (RFC), resulting in a replacement of isoleucine 48 by phenylalanine and of tryptophan 105 by glycine. Each mutation contributes to the resistance phenotype. Genomic DNA from resistant cells contained both the wild-type and mutant alleles, but wild-type message was not detected. Folic acid was a much better substrate, and 5-formyltetrahydrofolate was a poorer substrate for transport in L1210/D3 cells relative to L1210 cells. Enhanced transport of folic acid was due to a marked, approximately 20-fold, decrease in the influx Km. Influx of methotrexate and 5,10-dideazatetrahydrofolate were minimally altered. Transfection of mutated rfc cDNA into RFC-null L1210/A cells produced the substrate specificity and 5, 10-dideazatetrahydrofolate resistance observed in the L1210/D3 line. Transfection of the mutant cDNA into wild-type cells also conferred resistance to 5,10-dideazatetrahydrofolate. We conclude that the I48F and W105G mutations in RFC caused resistance to 5, 10-dideazatetrahydrofolate, that the region of the RFC protein near these two positions defines the substrate-binding site, that the wild-type allele was silenced during the multistep development of resistance, and that this mutant phenotype represents a genetically dominant trait.

Cellular folates prevent polyglutamation of 5, 10-dideazatetrahydrofolate. A novel mechanism of resistance to folate antimetabolites

Mouse L1210 cell variants were selected for resistance to 5, 10-dideazatetrahydrofolate, a potent inhibitor of the first folate-dependent enzyme in de novo purine synthesis, glycinamide ribonucleotide formyltransferase. The drug-resistant phenotype selected was conditional to the folate compound used to support growth: grown on folic acid cells were 400-fold resistant, whereas they were 2.5-fold more sensitive to 5,10-dideazatetrahydrofolate than wild-type L1210 cells when grown on folinic acid. In folic acid-containing media, polyglutamation of 5, 10-dideazatetrahydrofolate was markedly reduced, yet folylpolyglutamate synthetase activity was not different from that in parental L1210 cells. Resistance was due to two changes in membrane transport: a minor increase in the Km for 5, 10-dideazatetrahydrofolate influx, and a major increase in folic acid transport. Enhanced folic acid transport resulted in an expanded cellular content of folates which blocked polyglutamation of 5,10-dideazatetrahydrofolate. We propose that polyglutamation of 5,10-dideazatetrahydrofolate is limited by feedback inhibition by cellular folates on folylpolyglutamate synthetase, an effect which reflects a mechanism in place to control the level of cellular folates. Although the primary alteration causative of resistance is different from those reported previously, all 5, 10-dideazatetrahydrofolate resistance phenotypes result in decreased drug polyglutamation, reflecting the centrality of this reaction to the action of 5,10-dideazatetrahydrofolate.

Arginine vasopressin triggers intracellular calcium release, a calcium-activated potassium current and exocytosis in identified rat corticotropes

Arginine vasopressin (AVP) stimulates the secretion of ACTH from pituitary corticotropes. We investigated the action of AVP in single corticotropes of male rats. Corticotropes were identified with the reverse hemolytic plaque assay using antibodies against ACTH. Using the whole-cell recording technique in conjunction with the fluorescent Ca2+ indicator, indo-1 to measure the concentration of cytosolic free Ca2+ ([Ca2+]i), we show that AVP triggers a transient and plateau pattern of Ca2+ signal. The [Ca2+]i elevation activates the apamin-sensitive Ca2+-activated K+ current, which, in turn, causes membrane hyperpolarization. The Ca2+ signal can be elicited in the absence of extracellular Ca2+ and is mimicked by intracellular inositol 1,4,5-trisphosphate (IP3). Both GDP-beta-S and heparin inhibit the AVP response. Thus, AVP triggers intracellular Ca2+ release from the (IP3)-sensitive store via a GTP binding protein-coupled phosphoinositide pathway. Using the high temporal resolution capacitance measurement to detect exocytosis in single corticotropes, we show that a burst of exocytosis is evoked during the AVP-triggered [Ca2+]i elevation. Exocytosis can also be triggered when Ca2+ is released directly from the IP3-sensitive store via flash photolysis of caged IP3. We conclude that AVP-stimulated ACTH secretion in rat corticotrophs is closely coupled to intracellular Ca2+ release from the IP3-sensitive store.

Community Partnerships: Redirecting the Education of Undergraduate Nursing Students

Consistent with the goal of reforming nursing education to support nursing's agenda for health care reform, a community-based, multiprofessional initiative supported by the W.K. Kellogg Foundation began in Hawaii in 1991. This initiative created a partnership among the University of Hawaii Schools of Medicine, Nursing, Social Work, and Public Health, three community health centers, and their communities to provide a community-based, integrated system of health care, education, and research. In response to this initiative, the School of Nursing developed an integrated undergraduate curriculum consisting of: a discipline-specific tutorial using an inquiry-based learning strategy; a multiprofessional tutorial; and a 1-year clinical experience providing culturally competent primary care. Community-based education has stimulated changes in the philosophy, mission, and curriculum of the School of Nursing. The outcomes achieved as a result of this initiative have had a favorable impact on clients using the community health centers, the communities, the School of Nursing, and the students.

Mechanism underlying corticotropin-releasing hormone (CRH) triggered cytosolic Ca2+ rise in identified rat corticotrophs

1. The patch-clamp technique was used in conjunction with the fluorescent Ca2+ indicator indo-1 to measure simultaneously cytosolic Ca2+ concentration ([Ca2+]i) and membrane potential in single rat corticotrophs identified with the reverse haemolytic plaque assay. 2. Application of the adrenocorticotropin (ACTH) secretagogue, corticotropin-releasing hormone (CRH), triggered a sustained [Ca2+]i elevation and membrane depolarization. 3. The CRH action was mediated via the cAMP-dependent protein kinase cascade. Both the CRH-induced depolarization and [Ca2+]i elevation could be mimicked by extracellular application of the adenylate cyclase activator forskolin or the membrane-permeable cAMP analogue, 8-(4-chlorophenylthio)-adenosine-3',5'-cyclic monophosphate (8-CPT-cAMP). Intracellular adenosine cyclic 3',5'-(Rp)-phosphothioate (Rp-cAMPS), a protein kinase A inhibitor, abolished the CRH effects. 4. Voltage-clamp studies suggest that the CRH-triggered depolarization was due to the reduction of background K+ conductances. The CRH-sensitive current was Ca2+ independent and was insensitive to the K+ channel blockers tetraethylammonium (TEA) or 4-aminopyridine (4-AP), but could be partially inhibited by Ba2+. 5. The CRH-triggered steady-state depolarization stimulated extracellular Ca2+ entry via voltage-gated Ca2+ channels and raised [Ca2+]i. CRH failed to stimulate [Ca2+]i rise in cells that were voltage clamped at their resting potential. Removal of extracellular Ca2+ or inhibition of Ca2+ channels by Ni2+ abolished the [Ca2+]i rise. 6. Voltage-clamp studies of voltage-gated Ca2+ channels using Ba2+ as charge carrier show that approximately 90% of the channels were available for activation at the resting potential. CRH did not enhance the voltage-gated Ca2+ channels.

Post-tonsillectomy bacteraemia in children

It has been postulated that the bacteraemia rate following guillotine tonsillectomy is lower than that following dissection tonsillectomy due to intra-operative compression of tonsillar blood vessels by the guillotine. The aim of this study was to evaluate the incidence of bacteraemia following dissection and guillotine tonsillectomy. Sixty-four patients undergoing elective tonsillectomy for recurrent acute tonsillitis were randomly selected, 32 underwent dissection tonsillectomy and 32 guillotine tonsillectomy. Positive intra-operative blood cultures were obtained in 16 patients (25 per cent), nine (28.1 per cent) of the dissection group and seven (21.8 per cent) of the guillotine group. There was no significant difference between the two methods (Chi-squared test, p = 0.77).

Local Ca2+ release from internal stores controls exocytosis in pituitary gonadotrophs

Exocytosis and the cell-averaged cytosolic [Ca2+], [Ca2+]i, were tracked in single gonadotrophs. Cells released 100 granules/s at 1 microM = [Ca2+]i when gonadotropin-releasing hormone (GnRH) activated IP3-mediated Ca2+ release from internal stores, but only 1 granule/s when [Ca2+]i was raised uniformly to 1 microM by other means. Strong exocytosis was then seen only at higher [Ca2+]i (half-maximal at 16 microM). Parallel second messengers did not contribute to GnRH-induced exocytosis, because IP3 alone was as effective as GnRH, and because even GnRH failed to trigger rapid exocytosis when the [Ca2+]i rise was blunted by EGTA. When [Ca2+]i was released from stores, exocytosis depended on [Ca2+]i rising rapidly, as if governed by Ca2+ flux into the cytosol. We suggest that IP3 releases Ca2+ selectively from subsurface cisternae, raising [Ca2+] near exocytic sites 5-fold above the cell average.

Intraparotid facial nerve schwannoma in a child

Neoplasms of the facial nerve presenting as a parotid mass are uncommon. In the absence of a facial palsy their origin from the nerve is usually diagnosed intraoperatively. The majority of these neurogenic neoplasms are schwannomas, with neurofibromas occurring rarely. Although the Schwann cell is the key element in both, they have distinct histopathological characteristics, and their clinical course and management often differs. The first reported case of an intraparotid facial nerve schwannoma in a child in the English literature is presented.

Squamous cell carcinoma of the pharynx and larynx presenting as a neck abscess or cellulitis

Head and neck tumours presenting as a neck abscess or cellulitis are extremely rare. We report two cases of supraglottic squamous cell carcinoma which presented as an abscess in the site of metastatic neck nodes, one of which was occult and a third case of squamous cell carcinoma of the pyriform fossa which presented as cervical cellulitis. Biopsy of the abscess wall at the time of drainage and careful follow-up may lead to an earlier diagnosis of occult carcinoma.

Modulation of Ca2+ oscillation and apamin-sensitive, Ca2+-activated K+ current in rat gonadotropes

In rat pituitary gonadotropes, gonadotropin-releasing hormone (GnRH) stimulates rhythmic release of Ca2+ from stores sensitive to inositol 1,4,5-trisphosphate [Ins(1,4,5)P3], which in turn induces an oscillatory activation of apamin-sensitive Ca2+-activated K+ current, IK(Ca). Since GnRH also activates protein kinase C (PKC), we investigate the action of PKC while simultaneously measuring intracellular Ca2+ concentration ([Ca2+]i) and IK(Ca). Stimulation of PKC by application of phorbol 12-myristate 13-acetate (PMA) did not affect basal [Ca2+]i. However, PMA or phorbol 12,13-dibutyrate (PdBu), but not the inactive 4alpha-phorbol 12,13-didecanoate (4alpha-PDD), reduced the frequency of GnRH-induced [Ca2+]i oscillation and augmented the IK(Ca) induced by any given level of [Ca2+]i. The slowing of oscillations and the enhancement of IK(Ca) were mimicked by synthetic diacylglycerol (1,2-dioctanoyl-sn-glycerol) and could be induced during ongoing oscillations that had been initiated irreversibly in cells loaded with guanosine 5'-O-(3-thiotriphosphate) (GTP-[gammaS]). In contrast, when oscillations were initiated by loading cells with Ins(1,4,5)P3, phorbol esters enhanced IK(Ca) without affecting the frequency of oscillation. The protein kinase inhibitor, staurosporine, reduced IK(Ca) without affecting [Ca2+]i and partially reversed the phorbol-ester-induced slowing of oscillation. Therefore, activation of PKC has two rapid effects on gonadotropes. It slows [Ca2+]i oscillations probably by actions on phospholipase C, and it enhances IK(Ca) probably by a direct action on the channels.

Immunomodulatory and antiviral activities of 2',3'-dideoxy-beta-L-cytidine and 2',3'-dideoxy-beta-L-5-fluorocytidine

Two dideoxynucleosides, 2',3'-dideoxy-beta-L-cytidine and 2',3'-dideoxy-beta-L-5-flurocytidine, containing unnatural L-configuration in their sugar moieties, were synthesized and assayed for antiviral activities. Both compounds were shown to possess potent anti-human immunodeficiency virus type 1 and antihepatitis B virus activities, while demonstrating no anti-herpes simplex viruses 1 and 2 activity. These two compounds exhibited in vitro cellular toxicities for several leukocytic cell lines and were shown to inhibit phytohemagglutinin-stimulated human peripheral blood mononuclear leukocyte proliferations. At inhibitory concentrations, both compounds caused accumulations of cells in the S phase. While demonstrating no obvious morphological toxicity in vivo in mice at concentrations of 75 and 150 mg/kg, 2',3'-dideoxy-beta-L-5-fluorocytidine- treated animals were shown to have considerable increases in CD4/CD8 double positive T lymphocyte population in their blood circulation.

Cyclic Ca2+ changes in intracellular stores of gonadotropes during gonadotropin-releasing hormone-stimulated Ca2+ oscillations

Gonadotropin-releasing hormone induces oscillatory release of Ca2+ from inositol trisphosphate-sensitive stores of gonadotropes. Simultaneously with electrophysiological measures of cytoplasmic [Ca2+], corresponding changes in [Ca2+] within intracellular stores were monitored with a fluorescent dye, mag-indo-1. Each cycle of oscillation released only 10% of the detectable stored Ca2+. Some Ca2+ was recovered by the stores using a mechanism sensitive to inhibitors of intracellular Ca2+ ATPases, and much of the remainder was temporarily and rapidly pumped into other intracellular compartments or out of the cell. The dynamics of Ca2+ oscillations are thus more complex than a repeated emptying and refilling of a single compartment. The free concentrations measured show that intracellular Ca2+ store compartments contain strong Ca2+ buffers.

Effect of antibiotic treatment on inflammatory markers and lung function in cystic fibrosis patients with Pseudomonas cepacia

BACKGROUND

The acquisition of Pseudomonas cepacia in patients with cystic fibrosis is associated with increasing deterioration in lung function and more frequent hospital admissions. Pseudomonas cepacia is usually resistant to several antibiotics in vitro, but the response of patients colonised with the organism has not been extensively studied in vivo.

METHODS

A three month prospective study was performed to investigate the response of 14 Ps cepacia positive patients and 10 Ps cepacia negative patients to a two week course of intravenous antibiotics. All those who were Ps cepacia negative and six of the 14 Ps cepacia positive patients had Ps aeruginosa in their sputum which was sensitive to the prescribed therapy. The inflammatory markers C-reactive protein, white blood cell count, serum lactoferrin, neutrophil elastase/alpha 1-antitrypsin complex, and tumour necrosis factor alpha were measured at the start and end of each antibiotic course.

RESULTS

The median (range) % improvement in baseline FEV1 and FVC following treatment in the group as a whole was 15.2% (-23.5% to 156.3%) and 23.9% (-36.8% to 232.7%) respectively. There was no statistical difference in improvement in lung function, body weight, or inflammatory markers between individuals who were Ps cepacia positive and those who were Ps cepacia negative.

CONCLUSIONS

Patients who are Ps cepacia positive appear to respond as well to intravenous antibiotics as those who are Ps cepacia negative, despite having lower lung function and a bacterium in their sputum which is resistant in vitro to the antibiotics used.

Calcium homeostasis in identified rat gonadotrophs

1. Whole-cell voltage clamp was used in conjunction with the fluorescent Ca2+ indicator indo-1 to measure extracellular Ca2+ entry and intracellular Ca2+ concentrations ([Ca2+]i) in rat gonadotrophs identified with the reverse haemolytic plaque assay. 2. Depolarizations to potentials more positive than -40 mV elicited inward Ca2+ current (ICa) and transient elevations of [Ca2+]i. 3. The relationship between [Ca2+]i elevations and Ca2+ entry with different Ca2+ buffer concentrations in the pipette showed that endogenous Ca2+ buffers normally bind approximately 99% of the Ca2+ entering the cell. 4. With [Ca2+]i elevations less than 500 nM, decay of [Ca2+]i could be approximated by an exponential whose time constant increased with the concentration of exogenous Ca2+ buffers. 5. Inhibitors of intracellular Ca(2+)-ATPases, thapsigargin, cyclopiazonic acid (CPA) and 2,5-di-(tert-butyl)-1,4-benzohydroquinone (BHQ), caused [Ca2+]i to rise. Application of BHQ during [Ca2+]i oscillations induced by gonadotrophin-releasing hormone (GnRH) terminated the oscillation in a slowly decaying elevation. BHQ slowed the decay of depolarization-induced [Ca2+]i elevations about 3-fold. 6. Taking into account the Ca2+ buffering properties of the cytoplasm permitted estimation of the fluxes and rate constants for Ca2+ movements in gonadotrophs. The intracellular store is a major determinant of Ca2+ homeostasis in gonadotrophs.