Durable responses to ATR inhibition with ceralasertib in tumors with genomic defects and high inflammation

BACKGROUNDPhase 1 study of ATRinhibition alone or with radiation therapy (PATRIOT) was a first-in-human phase I study of the oral ATR (ataxia telangiectasia and Rad3-related) inhibitor ceralasertib (AZD6738) in advanced solid tumors.METHODSThe primary objective was safety. Secondary objectives included assessment of antitumor responses and pharmacokinetic (PK) and pharmacodynamic (PD) studies. Sixty-seven patients received 20-240 mg ceralasertib BD continuously or intermittently (14 of a 28-day cycle).RESULTSIntermittent dosing was better tolerated than continuous, which was associated with dose-limiting hematological toxicity. The recommended phase 2 dose of ceralasertib was 160 mg twice daily for 2 weeks in a 4-weekly cycle. Modulation of target and increased DNA damage were identified in tumor and surrogate PD. There were 5 (8%) confirmed partial responses (PRs) (40-240 mg BD), 34 (52%) stable disease (SD), including 1 unconfirmed PR, and 27 (41%) progressive disease. Durable responses were seen in tumors with loss of AT-rich interactive domain-containing protein 1A (ARID1A) and DNA damage-response defects. Treatment-modulated tumor and systemic immune markers and responding tumors were more immune inflamed than nonresponding.CONCLUSIONCeralasertib monotherapy was tolerated at 160 mg BD intermittently and associated with antitumor activity.TRIAL REGISTRATIONClinicaltrials.gov: NCT02223923, EudraCT: 2013-003994-84.FUNDINGCancer Research UK, AstraZeneca, UK Department of Health (National Institute for Health Research), Rosetrees Trust, Experimental Cancer Medicine Centre.

Harnessing radiotherapy-induced NK-cell activity by combining DNA damage-response inhibition and immune checkpoint blockade

BACKGROUND

Despite therapeutic gains from immune checkpoint inhibitors (ICI) in many tumor types, new strategies are needed to extend treatment benefits, especially in patients failing to mount effective antitumor T-cell responses. Radiation and drug therapies can profoundly affect the tumor immune microenvironment. Here, we aimed to identify immunotherapies to increase the antitumor response conferred by combined ataxia telangiectasia and Rad3-related kinase inhibition and radiotherapy.

METHODS

Using the human papillomavirus (HPV)-negative murine oral squamous cell carcinoma model, MOC2, we assessed the nature of the antitumor response following ataxia telangiectasia and Rad3-related inhibitor (ATRi)/radiotherapy (RT) by performing RNA sequencing and detailed flow cytometry analyses in tumors. The benefit of immunotherapies based on T cell immunoreceptor with Ig and ITIM domains (TIGIT) and Programmed cell death protein 1 (PD-1) immune checkpoint blockade following ATRi/RT treatment was assessed in the MOC2 model and confirmed in another HPV-negative murine oral squamous cell carcinoma model called SCC7. Finally, immune profiling was performed by flow cytometry on blood samples in patients with head and neck squamous cell carcinoma enrolled in the PATRIOT clinical trial of combined ATRi/RT.

RESULTS

ATRi enhances radiotherapy-induced inflammation in the tumor microenvironment, with natural killer (NK) cells playing a central role in maximizing treatment efficacy. We demonstrated that antitumor activity of NK cells can be further boosted with ICI targeting TIGIT and PD-1. Analyses of clinical samples from patients receiving ATRi (ceralasertib) confirm the translational potential of our preclinical studies.

CONCLUSION

This work delineates a previously unrecognized role for NK cells in the antitumor immune response to radiotherapy that can be augmented by small-molecule DNA damage-response inhibitors and immune checkpoint blockade.

Combination therapy with oncolytic viruses and immune checkpoint inhibitors

Introduction: Immune checkpoint inhibitors (ICI) have dramatically improved the outcome for cancer patients across multiple tumor types. However the response rates to ICI monotherapy remain relatively low, in part due to some tumors cultivating an inherently 'cold' immune microenvironment. Oncolytic viruses (OV) have the capability to promote a 'hotter' immune microenvironment which can improve the efficacy of ICI.Areas covered: In this article we conducted a literature search through Pubmed/Medline to identify relevant articles in both the pre-clinical and clinical settings for combining OVs with ICIs and discuss the impact of this approach on treatment as well as changes within the tumor microenvironment. We also explore the future directions of this novel combination strategy.Expert opinion: The imminent results of the Phase 3 study combining pembrolizumab with or without T-Vec injection are eagerly awaited. OV/ICI combinations remain one of the most promising avenues to explore in the success of cancer immunotherapy.

Patritumab with Cetuximab plus Platinum-Containing Therapy in Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck: An Open-Label, Phase Ib Study

PURPOSE

Patritumab plus cetuximab with platinum as first-line therapy for patients with recurrent and/or metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN) was evaluated for safety and to determine the recommended phase II combination dose.

PATIENTS AND METHODS

Patients aged ≥18 years with confirmed R/M SCCHN received intravenous patritumab (18 mg/kg loading dose; 9 mg/kg maintenance dose every 3 weeks) + cetuximab (400 mg/m² loading dose; 250 mg/m² maintenance dose weekly) + cisplatin (100 mg/m² every 3 weeks) or carboplatin (AUC of 5) for six cycles or until toxicity, disease progression, or withdrawal. Primary endpoints were dose-limiting toxicities [DLT; grade ≥3 (21-day observation period)] and treatment-emergent adverse events (TEAE). Pharmacokinetics, human antihuman antibodies (HAHA), tumor response, progression-free survival (PFS), and overall survival (OS) were assessed.

RESULTS

Fifteen patients completed a median (range) of 8.7 (2.0-20.7) patritumab cycles. No DLTs were reported. Serious adverse events were reported in 9 patients (patritumab-related n = 4). TEAEs (N = 15 patients) led to patritumab interruption in 7 patients. Patritumab-related dose reductions were reported in 1 patient. Patritumab (18 mg/kg) pharmacokinetics (N = 15) showed mean (SD) AUC_0-21d of 2,619 (560) μg/day/mL and maximum concentration of 499.9 (90.4) μg/mL. All patients were HAHA-negative at study end (single, transient low titer in 1 patient). Tumor response rate (complete plus partial response; N = 15) was 47%. Median (95% confidence interval) PFS and OS (N = 15) were 7.9 (3.7-9.7) and 13.5 (6.6-17.5) months, respectively.

CONCLUSIONS

Patritumab (18 mg/kg loading dose, 9 mg/kg maintenance dose) plus cetuximab/platinum was tolerable, active in SCCHN, and selected as the phase II dose regimen.

A practical guide to the handling and administration of talimogene laherparepvec in Europe

Talimogene laherparepvec is a herpes simplex virus-1-based intralesional oncolytic immunotherapy and is the first oncolytic virus to be approved in Europe. It is indicated for the treatment of adults with unresectable melanoma that is regionally or distantly metastatic (stage IIIB, IIIC, and IVM1a) with no bone, brain, lung, or other visceral disease. Talimogene laherparepvec is a genetically modified viral therapy, and its handling needs special attention due to its deep freeze, cold-chain requirements, its potential for viral shedding, and its administration by direct intralesional injection. This review provides a practical overview of handling, storage, and administration procedures for this agent in Europe. Talimogene laherparepvec vials should be transported/stored frozen at a temperature of −90°C to −70°C, and once thawed, vials must not be refrozen. Universal precautions for preparation, administration, and handling should be followed to avoid accidental exposure. Health care providers should wear personal protective equipment, and materials that come into contact with talimogene laherparepvec should be disposed of in accordance with local institutional procedures. Individuals who are immunocompromised or pregnant should not prepare or administer this agent. Talimogene laherparepvec is administered by intralesional injection into cutaneous, subcutaneous, and/or nodal lesions that are visible, palpable, or detectable by ultrasound. Treatment should be continued for ≥6 months. As with other immunotherapies, patients may experience an increase in the size of existing lesion(s) or the appearance of new lesions (ie, progression) prior to achieving a response (“pseudo-progression”). As several health care professionals (eg, physicians [dermatologists, surgeons, oncologists, radiologists], pharmacists, nurses) are involved in different stages of the process, there is a need for good interdisciplinary collaboration when using talimogene laherparepvec. Although there are specific requirements for this agent’s storage, handling, administration, and disposal, these can be effectively managed in a real-world clinical setting through the implementation of training programs and straightforward standard operating procedures.

The effect of parotid gland-sparing intensity-modulated radiotherapy on salivary composition, flow rate and xerostomia measures

OBJECTIVES

To describe parotid gland (PG) saliva organic and inorganic composition and flow rate changes, after curative intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC), and analyse the relationship between PG saliva analytes and xerostomia measures.

METHODS AND MATERIALS

Twenty-six patients recruited to five prospective phase 2 or 3 trials which assessed toxicity and efficacy of IMRT by HNC subsite, provided longitudinal PG saliva. Salivary flow rate, and subjective and objective xerostomia measures were prospectively collected and saliva tested for inorganic and organic analytes. Statistical comparisons of longitudinal analyte changes and analysis for a relationship between dichotomized xerostomia score and saliva analytes were performed.

RESULTS

One hundred and forty-two PG saliva samples from 26 patients were analysed. At 3-6 months after IMRT, stimulated and unstimulated saliva showed significantly decreased flow rate, total protein (TP) secretion rate, phosphate concentration and increased lactoferrin (LF) concentration. Stimulated saliva alone had elevated LF secretion rate and beta-2-microglobulin (B₂ M) concentration with decreased calcium (Ca²⁺ ) and magnesium (Mg²⁺ ) concentrations and Ca²⁺ secretion rate. At >12 months, under stimulated and unstimulated conditions, increased LF concentration and decreased Mg²⁺ and phosphate concentration persisted and, in stimulated saliva, there was decreased potassium (K⁺ ) and Mg²⁺ concentration. Unstimulated TP secretion rate was lower in the presence of high-grade xerostomia. Otherwise, no relationship between xerostomia grade and PG salivary flow rate, TP and Ca²⁺ secretion rate was found.

CONCLUSION

Fewer significant differences in PG saliva analytes >12 months after IMRT indicate good functional recovery. Residual xerostomia after IMRT will only be further reduced by addressing the sparing of subsites of the PG or other salivary gland tissues, in addition to the PG.

Predicting response to radical (chemo)radiotherapy (R-CRT) with circulating HPV DNA and tumor DNA (ctDNA) analysis in locally-advanced head and neck squamous cell carcinoma (LAHNC)

6043

Background: Following R-CRT for human papilloma virus positive (HPV+) and negative (HPV-) LAHNC, patients frequently undergo unnecessary neck dissection (ND) and/or repeated biopsies for abnormal PET-CT findings even in the presence of a complete pathological response (pCR), which causes significant morbidity. We assessed the role of circulating tumor DNA analysis in identifying patients with true residual disease. Methods: We prospectively recruited development (DC, n=55) and test (TC, n=33) cohorts of LAHNC patients having R-CRT. For HPV+ tumors we developed a novel amplicon based next generation sequencing assay (HPV-detect) to detect circulating HPV DNA and for HPV- tumors we used personalised droplet digital PCR assays of somatic mutations. Circulating tumor DNA levels at 12 weeks post-R-CRT were correlated to residual disease assessed by PET-CT and surgery. Results: In the DC (27 HPV+), baseline HPV-detect demonstrated 100% sensitivity and 93% specificity, confirmed in the TC (20 HPV+). 37 HPV+ patients (DC&TC) had complete samples-set. 36 had a negative HPV-detect at end of treatment, including 6 patients who underwent ND (3) and repeat primary site biopsies (3) for positive PET-CT but had pCR on surgical/biopsy specimen. 1 patient had positive HPV-detect and positive biopsy, indicating 100% agreement for HPV-detect and residual cancer. In a 10 HPV- patients with complete sample-set, there was 90% agreement between ctDNA and residual disease in HPV- tumors (3 ctDNA positive and tumor present, 1 ctDNA negative but tumor present, and 6 negative ctDNA negative tumor) with 80% sensitivity for residual disease and 100% specificity. Combined agreement between ctDNA testing (HPV+ and -) & residual disease was 98% (Table). Conclusions: Circulating HPV DNA quantified using HPV-detect and ctDNA identifies patients with residual disease post-R-CRT in LAHNC. Further studies are required to validate these findings. [Table: see text]

Blood transfusion during radical chemo-radiotherapy does not reduce tumour hypoxia in squamous cell cancer of the head and neck

BACKGROUND

Patients with head and neck squamous cell carcinoma (HNSCC) undergoing radical chemo-radiation (CRT) frequently receive transfusion with packed red cells (PRCT) during radiotherapy on the basis that PRCT increases tumour oxygenation and overcomes hypoxia-induced radio-resistance. This is likely to be a significant oversimplification given the fact that tumour hypoxia is the result of several intrinsic and extrinsic factors, including many that are not directly related to serum haemoglobin (Hb). Therefore, we have studied the effect of PRCT on tumour oxygenation in a prospective cohort of patients who developed low Hb during radical CRT for HNSCC.

METHODS

This was a prospective study of 20 patients with HNSCC receiving radical CRT undergoing PRCT for Hb<11.5 g dl-1. Patients underwent pretransfusion and posttransfusion intrinsic susceptibility-weighted (SWI) MRI and dynamic contrast-enhanced (DCE) MRI. Blood samples were obtained at the time of MRI scanning and two further time points for measuring Hb and a panel of serum cytokine markers of tumour hypoxia. 3D T2* and Ktrans maps were calculated from the MRI data for primary tumours and cervical lymph node metastases.

RESULTS

PRCT produced no change (11 patients) or reduced (1 patient) T2* (tumour oxygenation) in 12 of the 16 (75%) evaluable primary tumours. Three of the four patients with improved tumour oxygenation progressed or had partial response following treatment completion. There were variable changes in Ktrans (tumour perfusion or vessel permeability) following PRCT that were of small magnitude for most tumours. Pre- and Post-PRCT levels of measured cytokines were not significantly different.

CONCLUSIONS

This study suggests that PRCT during radical CRT for HNSCC does not improve tumour oxygenation. Therefore, oncologists should consider changing practice according to NICE and American Association of Blood Banks guidelines on PRCT for anaemia.

A randomised controlled trial of Caphosol mouthwash in management of radiation-induced mucositis in head and neck cancer

PURPOSE

This phase III, non-blinded, parallel-group, randomised controlled study evaluated the efficacy of Caphosol mouthwash in the management of radiation-induced oral mucositis (OM) in patients with head and neck cancer (HNC) undergoing radical (chemo)radiotherapy.

PATIENTS AND METHODS

Eligible patients were randomised at 1:1 to Caphosol plus standard oral care (intervention) or standard oral care alone (control), stratified by radiotherapy technique and use of concomitant chemotherapy. Patients in the intervention arm used Caphosol for 7weeks: 6weeks during and 1-week post-radiotherapy. The primary endpoint was the incidence of severe OM (CTCAE ⩾grade 3) during and up to week 8 post-radiotherapy. Secondary endpoints include pharyngeal mucositis, dysphagia, pain and quality of life.

RESULTS

The intervention (n=108) and control (n=107) arms were well balanced in terms of patient demographics and treatment characteristics. Following exclusion of patients with missing data, 210 patients were available for analysis. The incidence of severe OM did not differ between the intervention and control arms (64.1% versus 65.4%, p=0.839). Similarly, no significant benefit was observed for other secondary endpoints. Overall, compliance with the recommended frequency of Caphosol was low.

CONCLUSION

Caphosol did not reduce the incidence or duration of severe OM during and after radiotherapy in HNC.

Presentation of non-small cell lung cancer (NSCLC) in octogenarians

18555

Background: Lung cancer is the most common cause of cancer related death in the United States. Non-small cell lung cancer (NSCLC) accounts for over 80% of all new cases of lung cancer. Lung cancer is a disease of the elderly. There are only limited data available on NSCLC in octogenarians. Methods: From our institutional tumor registry, we identified all patients with NSCLC from 1995 to 2002 who were 80 years or older at the time of initial presentation. Data regarding overall stage, histology, date and extent of surgery, and co-morbidities were analyzed. Co-morbidity determination was based on the Adult Co-morbidity Evaluation (ACE-27) test, which ranges from 0 to 3 depending on severity of co-existing conditions. Results: At the time of initial presentation with NSCLC, 236 pts were 80 years or older. The distribution of stages were: stage I in 93 pts (39.5%), stage II in 15 pts (6.5%), stage III in 66 pts (28%) and stage IV in 62 pts (26%). Of the 236 patients the co-morbidity score was known for 223 pts. The distribution of the known scores was: 0, 39 pts (17.5%); 1, 79 pts (35%); 2, 68 pts (30.5%); and 3, 37 pts (17%). Only 35 patients in this cohort underwent surgery. Conclusions: 1. Despite a high proportion (46%) of early stage NSCLC, only a few elderly patients 80 years or older undergo surgical resection, likely because of co-morbid conditions. 2. Innovative non-surgical local modalities of therapy need to be studied in this population.

No significant financial relationships to disclose.

Non-small cell lung cancer in the new millennium: The effect of FDG-PET on stage distribution

7205

Background: The stage-wise distribution of NSCLC at the time of initial presentation following the widespread use of positron emission tomography with 2-[18F] fluoro-2-deoxy-D-glucose (FDG-PET) has not been characterized. Frequently quoted estimates of stage distribution are based predominantly on data prior to 2000. FDG-PET was approved in 1998 and has been widely utilized since 2000. We describe here the stage-wise distribution of NSCLC at the time of initial presentation over the past 15 years. Methods: Patients were identified and clinical data were obtained through our institutional tumor registry system. All patients diagnosed with NSCLC between January 1, 1990 and December 31, 2004 were included. All statistical comparisons were performed by X2 tests. Results: Of 6311 patients identified, 3926 were diagnosed prior to January 1, 2000 and 2385 thereafter. Pathological (surgical) staging was completed in 37% of patients. Given the widespread availability of FDG-PET since 2000, we grouped the analysis by date of diagnosis, before or after January 1, 2000. Before 2000, stage proportions were: I-29%; II-9%; III-31%; IV-30%; and unknown-1%. After January 1, 2000, stage proportions were: I-26%; II-9%; III-26%; IV-37%; and unknown-2%. The percentage of stage IV disease peaked at 40% in 2004. The difference in rates of stage IV disease before and after January 1, 2000 was highly significant (p < 0.0001). Conclusions: We have documented a significant change in the distribution of stages of non-small cell lung cancer in the last five years. The increase in stage IV disease and decreases in stages I & III disease coincide with the widespread adoption of FDG-PET, suggesting an earlier diagnosis of metastatic disease.

[Table: see text]

Inverse regulation of cyclin B1 by c-Myc and p53 and induction of tetraploidy by cyclin B1 overexpression

We have shown previously that mitotic spindle inhibitors allow the c-Myconcoprotein to uncouple mitosis from DNA synthesis, resulting in the acquisition of tetraploidy. This can also occur in the absence of spindle inhibition if c-Myc deregulation is combined with inactivation of the p53 tumor suppressor. Under these conditions, cyclin B1 protein is induced but retains its normal cell cycle regulation. We now show that the cyclin B1 promoter is directly but oppositely regulated by c-Myc and p53. Enforced expression of cyclin B1 also induces tetraploidy, either after mitotic spindle inhibition or in the absence of such inhibition if cyclin B1 is coexpressed with c-Myc. Cyclin B1 represents a new class of c-Myc target genes that is also regulated by p53. It is also the first identified downstream effector of c-Myc able to produce the chromosomal instability that characterizes virtually all tumor cells.

C-myc overexpression and p53 loss cooperate to promote genomic instability

p53 monitors genomic integrity at the G1 and G2/M cell cycle checkpoints. Cells lacking p53 may show gene amplification as well as the polyploidy or aneuploidy typical of many tumors. The pathways through which this develops, however, are not well defined. We demonstrate here that the combination of p53 inactivation and c-myc overexpression in diploid cells markedly accelerates the spontaneous development of tetraploidy. This is not seen with either N-myc or L-myc. Tetraploidy is accompanied by significantly higher levels of cyclin B and its associated cdc2 kinase activity. Mitotic spindle poisons accelerate the appearance of tetraploidy in cells either lacking functional p53 or overexpressing c-myc whereas the combination is additive. Restoration of p53 function in cells overexpressing c-myc causing rapid apoptosis, indicating that cells yet to become tetraploid have nonetheless suffered irreversible genomic and/or mitotic spindle damage. In the face of normal p53 function, such damage would either be repaired or trigger apoptotis. We propose that loss of p53 and overexpression of c-myc permits the emergence and survival of cells with increasingly severe damage and the eventual development of tetraploidy.

Mechanism of vasopressin natriuresis in the dog: role of vasopressin receptors and prostaglandins

Renal effects of physiological amounts of vasopressin were studied in conscious dogs during servocontrolled overhydration (2% body wt). During infusion of vasopressin (50 pg . min-1 . kg body wt-1), plasma vasopressin concentration increased to 2.30 +/- 0.20 pg/ml compared with 0.12 +/- 0.03 pg/ml during control (water diuresis). With vasopressin infusion, urine flow was significantly lower (0.30 +/- 0.10 ml/min) and sodium excretion (UNaV) was significantly higher (58.0 +/- 15.8 micromol/min) than without vasopressin (4.6 +/- 0.4 ml/min and 14.4 +/- 4.1 micromol/min, respectively). Deamino-[Cys1,D-Arg8]vasopressin, a V2 receptor agonist (4 pg . min-1 . kg-1), mimicked the antidiuretic response (0.20 +/- 0.03 ml/min) without changing UNaV (9.7 +/- 4.4 micromol/min). Indomethacin given during arginine vasopressin (AVP) infusion suppressed prostaglandin E2 excretion, intensified the antidiuresis (0.10 +/- 0.02 ml/min), and abolished the natriuresis (13.4 +/- 3.7 micromol/min). During AVP infusion, UNaV was highly correlated (r = 0.85) with prostaglandin E2 excretion. Blood pressure, glomerular filtration rate, plasma atrial natriuretic peptide concentration, and the rate of proximal tubule reabsorption (derived from lithium clearance) were similar in all series. The data indicate that, in the dog, physiological amounts of vasopressin can induce natriuresis, probably through activation of non-V2 receptors and the intrarenal synthesis of prostaglandins.

Lack of transcriptional repression by max homodimers

Max, a basic-helix-loop-helix-leucine zipper (bHLH-ZIP) protein, plays a central role in the transcriptional regulation of myc oncoprotein-responsive genes. Myc-max heterodimers bind to consensus E-box motifs near or within the promoters of these genes and activate gene expression, whereas heterodimers between max and members of the mad family of bHLH-ZIP proteins promote transcriptional repression. In contrast to all other members of the myc network, max readily homodimerizes and binds to identical E-box sites in vitro. However, the role for max homodimers in transcriptional repression in vivo is unclear. Upstream stimulatory factor (USF) is a bHLH-ZIP protein which does not interact with members of the myc-max-mad family. By replacing the HLH-ZIP domain of max with that from USF, we created a chimeric protein, max(USF), which was indistinguishable from max with respect to its ability to homodimerize and bind DNA. As expected, however, max(USF) was unable to heterodimerize with any of the tested max partner proteins and was incapable of suppressing c-myc target genes. Thus, transcriptional repression is an exclusive property of max-mad heterodimers and cannot be achieved by max homodimers alone.

Effects of receptor blockade on metabolism and renal actions of vasopressin in conscious dogs

Vasopressin--but not the V2 receptor agonist [deamino-cis1,D-Arg8]-vasopressin (dDAVP)--may mediate natriuresis in dogs. The present study investigated this phenomenon by use of nonpeptide antagonists to V1a and V2 receptors 1-¿1-[4-(3-acetylaminopropoxy)benzoyl]-4-piperidyl¿-3,4-dihydro-2 (1H)-quinolinone (OPC-21268) and 5-dimethylamino-1-¿4-(2-methylbenzoylamino)-benzoyl¿-2,3,4,5-tetra hydro-1 H-benzazepine (OPC-31260), respectively) hypothesising that only V1a inhibition would reduce the natriuresis. In conscious dogs vasopressin secretion was suppressed by water loading (2% body weight) and replaced by infusion of vasopressin (50 pg min-1 kg-1) resulting in physiological plasma concentrations (plasma levels of AVP (pAVP) = 2.0 +/- 0.1 pg mL-1). In this setting, OPC-21268 did not change the rate of sodium excretion. OPC-31260 increased water excretion 12-fold without significant changes in sodium excretion. Heart rate, mean arterial blood pressure, glomerular filtration rate, and clearance of endogenous Li+ were unchanged. During vasopressin infusion, both antagonists increased pAVP, OPC-21268 by 20% and OPC-31260 by 100% (2.0 +/- 0.2-4.0 +/- 0.3 pg mL-1). In the absence of vasopressin infusion, OPC-31260 did not increase pAVP. Thus, the increase in pAVP appeared to be due to a decrease in metabolic clearance rate. The results indicate that the present dose of V1a receptor inhibitor OPC-21268 does not reduce sodium excretion and that both vasopressin antagonists inhibit vasopressin metabolism.

Mmip1: a novel leucine zipper protein that reverses the suppressive effects of Mad family members on c-myc

C-myc, a member of the basic helix-loop-helix-leucine zipper (bHLH-ZIP) protein family activates target genes in heterodimeric association with another bHLH-ZIP protein, Max. Max readily homodimerizes, competes with C-myc-Max heterodimers, and represses transcription. Four additional bHLH-ZIP proteins, Mad1, Mxi1, Mad3 and Mad4, heterodimerize with Max and also repress transcription of c-myc-responsive genes. We employed a yeast two-hybid approach to identify proteins which interact with Mxi. We identified a novel ZIP-containing protein, Mmip1 (Mad member-interacting protein 1) that strongly dimerizes with all four Mad members, but not with c-myc, Max, or with unrelated HLH proteins. The Mmip1-Mxi association is mediated by the ZIP domain of each polypeptide and is as strong or stronger than the associations between c-myc and Max or Max and Mxi1. In vitro, Mmip1 can inhibit DNA binding by Max-Mad heterodimers and, in vivo, can reverse the suppressive effects of Mad proteins on c-myc functions. Mmipl is found in a variety of cells types, is induced by serum stimulation, and can be co-immunoprecipitated from fibroblasts in association with Mxi1. By interfering with the dimerization between Max and Mad family member proteins, Mmip1 can indirectly up-regulate the transcriptional activity of c-myc and suppress the antiproliferative actions of Mad proteins.

Novel regulation of the helix-loop-helix protein Id1 by S5a, a subunit of the 26 S proteasome

Id proteins negatively regulate the dimerization, DNA binding, and biological properties of basic helix-loop-helix proteins. In a search for novel factors that interact with Id1, we identified a component of the 26 S proteasome, S5a, that has previously been implicated only in the recognition of ubiquitinated polypeptides destined for proteolysis. S5a interacts strongly with Id1, less strongly with the basic helix-loop-helix proteins MyoD and E12, and not at all with other Id proteins. S5a restores DNA binding by MyoD-Id1 and E12-Id1 heterodimers, enhances DNA binding by MyoD and E12 homodimers, and reverses Id1-mediated repression of the muscle creatine kinase promoter during myogenic differentiation. Mutagenesis experiments showed that amino acids flanking the helix-loop-helix domain plus three residues in the first helix of Id1 impart S5a recognition. This requires only the NH2-terminal half of S5a. S5a thus appears to promote the positive regulation of myogenic genes through ubiquitin-independent mechanisms involving inhibition of Id1 and the enhancement of DNA binding by MyoD and E12. This latter property may permit the selection of novel promoter binding sites during myogenesis.

An evaluation of automated defibrillation and manual defibrillation by emergency medical technicians in a rural setting

We show that automated external defibrillation training of emergency medical technicians (EMTs) is less time consuming than manual defibrillation training, and hypothesize that both improve survival from sudden cardiac death. Data on 91 cardiac arrests over 27 months among five basic life support services was collected before EMT-defibrillation (EMT-D) training. Subsequently, seven BLS services were trained in EMT-D using either manual difibrillation or automated external defibrillation technology, and 55 sudden cardiac death patients were entered after training. Manual defibrillation required 11 more hours per student in initial training. Survival to hospital discharge improved from two of 91 patients (2.2%) in the series before EMT-D training to nine of 55 patients (16.4%) after EMT-D training (P = .001). Improved survival was correlated with shorter prehospital defibrillation times, 8.84 minutes, when EMTs performed defibrillation versus 16.3 minutes before training when EMTs awaited advanced life support defibrillation (P < .001). To enhance equipment familiarity we allowed EMTs to apply three-lead electrode monitors to all medical/cardiac patients during transport (surveillance). There were six emergency medical service-witnessed "surveillance" arrests and three arrests survived to hospital discharge (50% survival). This group represented 33% of all survivors in the series. We recommend automated external defibrillation training for EMTs. Improved survival in sudden cardiac death cases in well-run emergency medical service systems should result from EMT-D training. Finally, we recommend that routine "surveillance" of high-risk patients during transport by defibrillation-capable EMTs be considered in EMT-D programs, rather than limiting EMT-D only to units capable of rapid "man-down" response.

Effects of d-amphetamine and diazepam on paired and grouped primate food competition

Two male and two female rhesus monkeys (Macaca mulatta) were the subjects of an experiment designed to assess the effect of d-amphetamine (DA; 0.125, 0.5 and 2.0 mg/kg, IM) and diazepam (DZP; 0.5 and 2.5 mg/kg, IM) on food-getting behavior in paired and group competition. Paired competition results show that in some cases submissive animals, that had previously failed to obtain apple pieces, were successful in obtaining some apple pieces when either the dominant animal of the pair or both subjects were given 0.5 mg/kg DA or 2.5 mg/kg DZP. Results revealed the same effect when all animals (group competition) were given 0.125 and 2.0 mg/kg DA and 2.5 mg/kg DZP. These results appear to indicate that the effect of drugs on food-getting behavior in competitive situations is in some manner influenced by the social status of the animal.

Benzhexol and side effects with long-acting fluphenazine therapy

Sixteen patients who had for some months been on fluphenazine enanthate injections (1-3 ml) every two or three weeks, with daily oral benzhexol (6-40 mg), were divided into two groups comparable in age, diagnostic category, and drug dose.Placebo was substituted under blind controlled conditions for benzhexol in one group, and both groups were regularly assessed by Simpson rating scale for extra-pyramidal signs, and by a 30-question symptom check list. Both assessments were found reliable.Four out of eight patients had severe reactions when off benzhexol, but symptoms such as tremor and daytime sleepiness were unaltered in all patients. The other four did not suffer adversely from withdrawal of benzhexol.Acute withdrawal is therefore unjustified, but occasional revision of dosage of anti-Parkinsonian drugs is advisable. There is no evidence that tolerance develops to any effect of a phenothiazine, but long-continued benzhexol might induce a denervation supersensitivity. It is also possible that Parkinsonian signs are dependent on affective state.