Efficacy and pharmacodynamic effect of anti-CD73 and anti-PD-L1 monoclonal antibodies in combination with cytotoxic therapy: observations from mouse tumor models

CD73 is a cell surface 5'nucleotidase (NT5E) and key node in the catabolic process generating immunosuppressive adenosine in cancer. Using a murine monoclonal antibody surrogate of Oleclumab, we investigated the effect of CD73 inhibition in concert with cytotoxic therapies (chemotherapies as well as fractionated radiotherapy) and PD-L1 blockade. Our results highlight improved survival in syngeneic tumor models of colorectal cancer (CT26 and MC38) and sarcoma (MCA205). This therapeutic outcome was in part driven by cytotoxic CD8 T-cells, as evidenced by the detrimental effect of CD8 depleting antibody treatment of MCA205 tumor bearing mice treated with anti-CD73, anti-PD-L1 and 5-Fluorouracil+Oxaliplatin (5FU+OHP). We hypothesize that the improved responses are tumor microenvironment (TME)-driven, as suggested by the lack of anti-CD73 enhanced cytopathic effects mediated by 5FU+OHP on cell lines in vitro. Pharmacodynamic analysis, using imaging mass cytometry and RNA-sequencing, revealed noteworthy changes in specific cell populations like cytotoxic T cells, B cells and NK cells in the CT26 TME. Transcriptomic analysis highlighted treatment-related modulation of gene profiles associated with an immune response, NK and T-cell activation, T cell receptor signaling and interferon (types 1 & 2) pathways. Inclusion of comparator groups representing the various components of the combination allowed deconvolution of contribution of the individual therapeutic elements; highlighting specific effects mediated by the anti-CD73 antibody with respect to immune-cell representation, chemotaxis and myeloid biology. These pre-clinical data reflect complementarity of adenosine blockade with cytotoxic therapy, and T-cell checkpoint inhibition, and provides new mechanistic insights in support of combination therapy.

Environments that promote recovery in acute care mental health: nursing perspectives explored through interpretative description

BACKGROUND

A significant change in mental health care has involved the need to implement recovery-oriented practices and services. However, recovery-oriented care has been poorly defined within acute care mental health settings.

OBJECTIVES

The central aims of the study were to increase knowledge about what constitutes a recovery-oriented environment within contemporary acute care units and to inform recovery-oriented nursing practice.

METHODS

Interpretative description was applied to answer the question: What strategies and resources do nurses identify as being most conducive to fostering a recovery-oriented environment in acute care mental health units? Purposive sampling was used to recruit 11 nurses from 6 acute care units. The inclusion criteria included a minimum of 1-year patients and holding active nursing registration. Nursing experience in community-based or chronic care settings and with children and adolescents were exclusion criteria. Six nurses also participated in a focus group.

RESULTS

Key aspects of a recovery-oriented acute care environment included understanding the needs of individual patients along with the dynamics of the healthcare team. Nurses had important roles in promoting recovery-oriented environments and reported a need for increased resources to move beyond the bio-medical model and align practice with personal recovery.

CONCLUSION

A recovery-oriented environment was described as a safe, peaceful and holistic environment with adequate space to balance needs for privacy, interaction and activity. This environment is fostered through respectful communication and healthy relationships among team members, patients, family and formal supports. These nurses had the knowledge, skill and desire to promote recovery-oriented environments, yet resources such as leisure activities and group therapy were required to promote personal recovery.

25 A Pilot Implementation of Providing Enhanced Support to Care Homes within A Primary Care Network

Introduction

People living with severe frailty in care homes are vulnerable to frequent non-elective hospital attendances. However provision of enhanced healthcare support to care home residents can reduce this risk and increase quality of life for residents.1 The framework for enhanced health in care homes (EHCH) summarises best practice in this area and provides guidance for implementing services.2

Methods

This study was a pilot implementation of the EHCH framework based on a Primary Care and Specialist Frailty Multidisciplinary Team (MDT) and delivered on a Primary Care Network (PCN) footprint. The MDT targeted five care homes in a PCN area with historically high levels of non-elective attendances. The model of care was based on the principle of anticipatory care planning, training and support for care home staff to understand and implement plans.

Results

Over the pilot period of 9 months, non-elective attendances from the 5 homes reduced by 27% compared to the previous year, which was a significant reduction (p<0.042). There was variation between the homes in the reduction in non-elective attendances with the greatest impact seen in the homes that had the highest level of attendance at training and engagement in the care planning process. Feedback received from the care home staff indicated that they felt more confident to refer to the care plans and had alternative options to calling 999. A quality audit of the care plans completed as part of the pilot revealed a number of additional training needs for clinicians completing the plans to ensure consistency of recoding. This training was delivered following the pilot period.

Conclusions

The pilot demonstrated that the EHCH framework could be successfully implemented on a PCN footprint. Analysis shows this implementation coincided with a reduction in non-elective attendances from the targeted homes. Further analysis is required to compare the impact in different homes and to understand contributing factors. The pilot implementation provides helpful information to inform PCN development.

References

1. Lloyd T, Wolters A and Steveton A (2014) The impact of providing enhanced support for care home residents in Rushcliffe: Health Foundation consideration of findings from the Improvement Analytics Unit. The Health Foundation.

2. NHS England (2016) The framework for enhanced health in care homes.

Determination of Arsenic, Cadmium, Cobalt, Chromium, Lead, Molybdenum, Nickel, and Selenium in Fertilizers by Microwave Digestion and Inductively Coupled Plasma-Optical Emission Spectrometry Detection: Collaborative Study

There is increasing regulatory interest in the non-nutritive metals content of fertilizer materials, but at present there is no consensus analytical method for acid digestion and instrument detection of those elements in fertilizer matrixes. This lack of method standardization has resulted in unacceptable variability of results between fertilizer laboratories performing metals analysis. A method has been developed using microwave digestion with nitric acid at 200C, followed by inductively coupled plasma-optical emission spectrometry instrument detection, for the elements arsenic, cadmium, cobalt, chromium, molybdenum, nickel, lead, and selenium. The method has been collaboratively studied, and statistical results are here reported. Fourteen collaborators were sent 62 sample materials in a blind duplicate design. Materials represented a broad cross section of fertilizer types, including phosphateore, manufactured phosphate products, N-P-K blends, organic fertilizers, and micro-nutrient materials. As much as possible within the limit of the number of samples, materials were selected from different regions of the United States and the world. Limit of detection (LOD) was determined using synthetic fertilizers consisting of reagent grade chemicals with near zero levels of the non-nutritive elements, analyzed blindly. Samples with high iron content caused the most variability between laboratories. Most samples reasonably above LOD gave HorRat values within the range 0.5 to 2.0, indicating acceptable method performance according to AOAC guidelines for analyses in the mg/kg range. The method is recommended for AOAC Official First Action status.

The MEK inhibitor selumetinib complements CTLA-4 blockade by reprogramming the tumor immune microenvironment

Background

T-cell checkpoint blockade and MEK inhibitor combinations are under clinical investigation. Despite progress elucidating the immuno-modulatory effects of MEK inhibitors as standalone therapies, the impact of MEK inhibition on the activity of T-cell checkpoint inhibitors remains incompletely understood. Here we sought to characterize the combined effects of MEK inhibition and anti-CTLA-4 mAb (anti-CTLA-4) therapy, examining effects on both T-cells and tumor microenvironment (TME).

Methods

In mice, the effects of MEK inhibition, via selumetinib, and anti-CTLA-4 on immune responses to keyhole limpet haemocyanin (KLH) immunization were monitored using ex vivo functional assays with splenocytes. In a KRAS-mutant CT26 mouse colorectal cancer model, the impact on the tumor microenvironment (TME) and the spleen were evaluated by flow cytometry. The TME was further examined by gene expression and immunohistochemical analyses. The combination and sequencing of selumetinib and anti-CTLA-4 were also evaluated in efficacy studies using the CT26 mouse syngeneic model.

Results

Anti-CTLA-4 enhanced the generation of KLH specific immunity following KLH immunization in vivo; selumetinib was found to reduce, but did not prevent, this enhancement of immune response by anti-CTLA-4 in vivo. In the CT26 mouse model, anti-CTLA-4 treatment led to higher expression levels of the immunosuppressive mediators, Cox-2 and Arg1 in the TME. Combination of anti-CTLA-4 with selumetinib negated this up-regulation of Cox-2 and Arg1, reduced the frequency of CD11⁺ Ly6G⁺ myeloid cells, and led to the accumulation of differentiating monocytes at the Ly6C⁺ MHC⁺ intermediate state in the tumor. We also report that MEK inhibition had limited impact on anti-CTLA-4-mediated increases in T-cell infiltration and T-cell activation in CT26 tumors. Finally, we show that pre-treatment, but not concurrent treatment, with selumetinib enhanced the anti-tumor activity of anti-CTLA-4 in the CT26 model.

Conclusion

These data provide evidence that MEK inhibition can lead to changes in myeloid cells and immunosuppressive factors in the tumor, thus potentially conditioning the TME to facilitate improved response to anti-CTLA-4 treatment. In summary, the use of MEK inhibitors to alter the TME as an approach to enhance the activities of immune checkpoint inhibitors warrants further investigation in clinical trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s40425-017-0268-8) contains supplementary material, which is available to authorized users.

Using junior doctors to improve patient care: Creating a clinic to monitor the physical health of patients prescribed clozapine

Introduction

In the United Kingdom, compliance with guidelines on physical health monitoring of patients prescribed clozapine is poor. Our community team established a ‘clozapine clinic’, led by junior doctors, to monitor the physical health of this population.

Aims

The aims of this audit were:

– to ascertain levels of compliance with guidelines on the physical health monitoring of patients taking clozapine;

– to compare the current level of compliance with that prior to the establishment of the clinic.

Methods

Eleven standards were drawn from National Institute for Health and Care Excellence guidelines and the Maudsley Prescribing Guidelines in Psychiatry.

Three audit cycles were conducted: two prior to the establishment of the clinic and one after. In each cycle, searches of patient records were conducted and blood results were reviewed. This was supplemented by telephone calls to general practitioners to ensure a complete data set.

Analysis was conducted in Microsoft Excel™ and changes between the cycles were analysed using a two-tailed Z-score.

Results

Each audit cycle included 28–30 patients. In the current cycle compliance levels varied between 66% (annual ECG recording) and 100% (monthly full blood count). The average compliance level was 73% across all standards. This represents an overall improvement on previous audit cycles. Since the clinic was established there has been a statistically significant improvement in compliance with annual monitoring of weight (P = 0.147), body mass index (P = 0.0178), and ECG monitoring (P = 0.0244).

Conclusions

Improvements in the care of a vulnerable population may be achieved through setting clear standards, regular audit, and harnessing the leadership and enthusiasm of junior doctors.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Transformation of the tumour microenvironment by a CD40 agonist antibody correlates with improved responses to PD-L1 blockade in a mouse orthotopic pancreatic tumour model

Despite the availability of recently developed chemotherapy regimens, survival times for pancreatic cancer patients remain poor. These patients also respond poorly to immune checkpoint blockade therapies (anti-CTLA-4, anti-PD-L1, anti-PD-1), which suggests the presence of additional immunosuppressive mechanisms in the pancreatic tumour microenvironment (TME). CD40 agonist antibodies (αCD40) promote antigen presenting cell (APC) maturation and enhance macrophage tumouricidal activity, and may therefore alter the pancreatic TME to increase sensitivity to immune checkpoint blockade. Here, we test whether αCD40 transforms the TME in a mouse syngeneic orthotopic model of pancreatic cancer, to increase sensitivity to PD-L1 blockade. We found that whilst mice bearing orthotopic Pan02 tumours responded poorly to PD-L1 blockade, αCD40 improved overall survival. αCD40 transformed the TME, upregulating Th1 chemokines, increasing cytotoxic T cell infiltration and promoting formation of an immune cell-rich capsule separating the tumour from the normal pancreas. Furthermore, αCD40 drove systemic APC maturation, memory T cell expansion, and upregulated tumour and systemic PD-L1 expression. Combining αCD40 with PD-L1 blockade enhanced anti-tumour immunity and improved overall survival versus either monotherapy. These data provide further support for the potential of combining αCD40 with immune checkpoint blockade to promote anti-tumour immunity in pancreatic cancer.

Rational Selection of Syngeneic Preclinical Tumor Models for Immunotherapeutic Drug Discovery

Murine syngeneic tumor models are critical to novel immuno-based therapy development, but the molecular and immunologic features of these models are still not clearly defined. The translational relevance of differences between the models is not fully understood, impeding appropriate preclinical model selection for target validation, and ultimately hindering drug development. Across a panel of commonly used murine syngeneic tumor models, we showed variable responsiveness to immunotherapies. We used array comparative genomic hybridization, whole-exome sequencing, exon microarray analysis, and flow cytometry to extensively characterize these models, which revealed striking differences that may underlie these contrasting response profiles. We identified strong differential gene expression in immune-related pathways and changes in immune cell-specific genes that suggested differences in tumor immune infiltrates between models. Further investigation using flow cytometry showed differences in both the composition and magnitude of the tumor immune infiltrates, identifying models that harbor "inflamed" and "non-inflamed" tumor immune infiltrate phenotypes. We also found that immunosuppressive cell types predominated in syngeneic mouse tumor models that did not respond to immune-checkpoint blockade, whereas cytotoxic effector immune cells were enriched in responsive models. A cytotoxic cell-rich tumor immune infiltrate has been correlated with increased efficacy of immunotherapies in the clinic, and these differences could underlie the varying response profiles to immunotherapy between the syngeneic models. This characterization highlighted the importance of extensive profiling and will enable investigators to select appropriate models to interrogate the activity of immunotherapies as well as combinations with targeted therapies in vivo Cancer Immunol Res; 5(1); 29-41. ©2016 AACR.

Abstract 1475: Local immune activation resulting in tumor growth inhibition with MEDI9197 - an intratumorally administered TLR7/8 agonist

MEDI9197 (formerly 3M-052) is a sustained-release imidazoquinoline toll like receptor (TLR) TLR7/8 agonist designed with a lipid tail that, when injected, is retained within the tumor. This has been shown in pharmacokinetic studies in mice and rats injected with MEDI9197 via the subcutaneous (SC) or intratumoral (IT, mouse only) routes. Stimulation of TLR7 and TLR8 in primary human dendritic cells induces the release of interferon-alpha (IFN-a) from plasmacytoid dendritic cells (pDCs) and interleukin 12 (IL-12) from myeloid dendritic cells (mDCs). Intratumoral administration of MEDI9197 induces a local immune response characterized by upregulation of genes involved in activation of innate and adaptive immunity both from the injected tumor and tumor draining lymph node. Furthermore, flow cytometric analysis of tumor infiltrating lymphocytes (TILs) show increased expression of activation markers, such as CD69, on natural killer (NK) cells and CD8 cytotoxic T cells. This local stimulation of immune cells with MEDI9197 results in tumor growth inhibition as shown in the B16F10 luc syngeneic mouse tumor model using in vivo imaging system (IVIS) equipment. Additionally, combination of MEDI9197 with immune checkpoint inhibitors enhances the efficacy observed in syngeneic mouse tumor models. The data presented shows intratumoral administration of MEDI9197 induces local immune activation leading to tumor growth inhibition in preclinical models of cancer. MEDI9197 is currently being evaluated as a monotherapy for safety and efficacy in human clinical trials.

Citation Format: Stefanie Mullins, Iwen Grigsby, Lester I. Harrison, Song Ren, Serguei Soukharev, Lesley Young, James M. Elvecrog, Robert W. Wilkinson, Mark A. Tomai, Ronald Herbst, John P. Vasilakos, Andrew J. Leishman. Local immune activation resulting in tumor growth inhibition with MEDI9197 - an intratumorally administered TLR7/8 agonist. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1475.

Identification and Characterization of MEDI4736, an Antagonistic Anti-PD-L1 Monoclonal Antibody

Programmed cell-death 1 ligand 1 (PD-L1) is a member of the B7/CD28 family of proteins that control T-cell activation. Many tumors can upregulate expression of PD-L1, inhibiting antitumor T-cell responses and avoiding immune surveillance and elimination. We have identified and characterized MEDI4736, a human IgG1 monoclonal antibody that binds with high affinity and specificity to PD-L1 and is uniquely engineered to prevent antibody-dependent cell-mediated cytotoxicity. In vitro assays demonstrate that MEDI4736 is a potent antagonist of PD-L1 function, blocking interaction with PD-1 and CD80 to overcome inhibition of primary human T-cell activation. In vivo MEDI4736 significantly inhibits the growth of human tumors in a novel xenograft model containing coimplanted human T cells. This activity is entirely dependent on the presence of transplanted T cells, supporting the immunological mechanism of action for MEDI4736. To further determine the utility of PD-L1 blockade, an anti-mouse PD-L1 antibody was investigated in immunocompetent mice. Here, anti-mouse PD-L1 significantly improved survival of mice implanted with CT26 colorectal cancer cells. The antitumor activity of anti-PD-L1 was enhanced by combination with oxaliplatin, which resulted in increased release of HMGB1 within CT26 tumors. Taken together, our results demonstrate that inhibition of PD-L1 function can have potent antitumor activity when used as monotherapy or in combination in preclinical models, and suggest it may be a promising therapeutic approach for the treatment of cancer. MEDI4736 is currently in several clinical trials both alone and in combination with other agents, including anti-CTLA-4, anti-PD-1, and inhibitors of IDO, MEK, BRAF, and EGFR.

Abstract 1651: Profiling immune cells within the tumor microenvironment for optimal model selection for pre-clinical investigations

Infiltrating host immune cells can have a significant impact on the growth and outcome of many tumor types. Several leukocyte populations have been implicated in establishing an immune suppressive microenvironment (e.g. myeloid derived suppressor cells [MDSCs) and regulatory T cells [Treg cells]) and thus making it harder for anti-tumor immune effector cells to function (e.g. CD8 cytotoxic T cells). Immune-Mediated Therapy (IMT) is emerging as a key strategy for the treatment of cancer through by enhancing a patient's anti-tumor immune response. In order to maximise the potential of IMT strategies it is important to understand the immune status within the tumor microenvironment as well as systemically. Therefore, fully immune-competent preclinical models are valuable tools to enable the study of the immune system, both locally within the tumor and systemically, to understand the mechanism of action of IMT monotherapies and combination therapies in vivo. Consequently, we have profiled the immune status of a panel of syngeneic mouse tumor models to assist optimal model selection to aid these investigations. We developed multi-parameter flow cytometry techniques to identify specific immune subsets in both the tumor microenvironment and the periphery. These investigations revealed a number of tumor infiltrating immune cell end-points that can be used to correlate with response to IMT depending on the syngeneic model being used. For example, we observed differences in the MDSC and Treg cell populations across the models investigated, which will influence optimal model selection depending on the mechanism of action of the IMT being tested.

Citation Format: Andrew Leishman, Olivia Harris, Jane Coates Ulrichsen, James Harper, Amy Popple, Marianna Papaspyridonos, Geoff Williams, Stefanie Mullins, Viia Valge-Archer, Ross Stewart, Richard Sainson, Michelle Morrow, Robert Wilkinson. Profiling immune cells within the tumor microenvironment for optimal model selection for pre-clinical investigations. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1651. doi:10.1158/1538-7445.AM2014-1651

Preclinical modelling of immune checkpoint blockade (P2012)

Harnessing the power of the immune system to identify and eliminate cancer is a promising area of development in cancer therapy. Increasing T-cell activation, in particular, is now a clinically validated approach to the treatment of cancer. Cytotoxic T lymphocyte antigen 4 (CTLA-4, CD152) and PD-L1 (B7-H1, CD274) are part of a complex system of receptors and ligands that are involved in limiting T-cell activation through the delivery of inhibitory signals. MedImmune is currently developing tremelimumab (anti-CTLA4) and MEDI4736 (anti-PD-L1), for the treatment of advanced or metastatic solid tumours. Both of these antibodies antagonise T-cell inhibition signals with the aim of enhancing anti-tumor T cell activity. We have established and characterised a panel of syngeneic mouse tumor models and employed these to explore the activity of anti-mouse CTLA-4 and PD-L1 antibodies using pharmacodynamic (PD) and tumor growth inhibition (TGI) endpoints. Published studies characterising the immunogenic nature of some existing cancer therapeutics provide reason to believe that a combination strategy, utilising checkpoint blockade together with current standard of care, or novel therapeutics, could result in increased activity. We have gone on to explore the value of such combinations in preclinical mouse models.

Photodynamic molecular beacon triggered by fibroblast activation protein on cancer-associated fibroblasts for diagnosis and treatment of epithelial cancers

Fibroblast activation protein (FAP) is a cell-surface serine protease highly expressed on cancer-associated fibroblasts of human epithelial carcinomas but not on normal fibroblasts, normal tissues, and cancer cells. We report herein a novel FAP-triggered photodynamic molecular beacon (FAP-PPB) comprising a fluorescent photosensitizer and a black hole quencher 3 linked by a peptide sequence (TSGPNQEQK) specific to FAP. FAP-PPB was effectively cleaved by both human FAP and murine FAP. By use of the HEK293 transfected cells (HEK-mFAP, FAP(+); HEK-vector, FAP(-)), systematic in vitro and in vivo experiments validated the FAP-specific activation of FAP-PPB in cancer cells and mouse xenografts, respectively. FAP-PPB was cleaved by FAP, allowing fluorescence restoration in FAP-expressing cells while leaving non-expressing FAP cells undetectable. Moreover, FAP-PPB showed FAP-specific photocytotoxicity toward HEK-mFAP cells whereas it was non-cytotoxic toward HEK-Vector cells. This study suggests that the FAP-PPB is a potentially useful tool for epithelial cancer detection and treatment.

Potent alpha 4 beta 1 peptide antagonists as potential anti-inflammatory agents

The migration, adhesion, and subsequent extravasation of leukocytes into inflamed tissues contribute to the pathogenesis of a variety of inflammatory diseases including asthma, rheumatoid arthritis, inflammatory bowel disease, and multiple sclerosis. The integrin adhesion receptor alpha 4 beta 1 expressed on leukocytes binds to the extracellular matrix protein fibronectin and to the cytokine inducible vascular cell adhesion molecule-1 (VCAM-1) at inflamed sites. Binding of alpha 4 beta 1 to VCAM-1 initiates firm adhesion of the leukocyte to the vascular endothelium followed by extravasation into the tissue. Monoclonal antibodies generated against either alpha 4 beta 1 or VCAM-1 can moderate this inflammatory response in a variety of animal models. Recently peptides containing a consensus LDV sequence based on the connecting segment-1 (CS-1) of fibronectin and cyclic peptides containing an RCD motif have shown promise in modulating leukocyte migration and inflammation presumably by blocking the interaction of alpha 4 beta 1 with VCAM-1. Here we describe novel, highly potent, cyclic peptides that competitively inhibit alpha 4 beta 1 binding to VCAM-1 and fibronectin at sub nanomolar concentrations. The structure of a representative analog was determined via NMR spectroscopy and used to facilitate optimization of peptide leads. The peptides discussed here utilize similar functional groups as the binding epitope of VCAM-1, inhibit lymphocyte migration in vivo, and are highly selective for alpha 4 beta 1. Furthermore the structure--activity relationships described here have provided a template for the structure-based design of small molecule antagonists of alpha 4 beta 1-mediated cell adhesion processes.

Laparoscopic management of failed antireflux surgery

Whether performed open or laparoscopically, antireflux procedures for gastroesophageal reflux disease sometimes fail and may require reoperation for optimal results. Between June 1992 and May 1995 eight patients presented with a failed antireflux procedure. Four patients had previously had a Belsey operation performed through the chest, two had had open Nissen fundoplications, and two had Nissen fundoplications performed via laparoscopy. Preoperative workup included cardiac, hematologic, and pulmonary evaluation as well as Esophagogastroduodenscopy (EGD), esophageal manometry, and 24-h pH studies to document reflux as a cause of recurrent symptoms. Two patients had aspiration symptoms even on medication. All patients had severe esophagitis on biopsy. Six reoperations (75%) were completed laparoscopically. In two patients we converted to open procedures due to an inability to expose the esophageal hiatus secondary to adhesions between the left lobe of the liver and the stomach. Of the six patients completed laparoscopically, one had a Nissen fundoplication and the others had a 200 degrees partial wrap. Two patients developed left pneumothorax, one patient required a single postoperative dilation, and one patient treated with open surgery developed pneumonia. The average hospitalization for laparoscopy was 2.2 days (range, 1-4 days), while those two who underwent open surgery stayed in the hospital 5 and 6 days. All patients were followed from 12 to 42 months and all are currently off medication and free of symptoms. Laparoscopic re-exploration for esophageal reflux disease can be safely performed with excellent results.

Rapidly progressive CD8-positive cutaneous T-cell lymphoma with tongue involvement

Cutaneous T-cell lymphoma rarely involves the oral cavity. We describe the histological and immunological findings of a rapidly progressive CD8+ cutaneous T-cell lymphoma involving the tongue. Involvement of the oral cavity usually indicates a poor prognosis. Cases of cutaneous T-cell lymphoma with oral involvement as reported in the English-language literature are reviewed and discussed.

Synthesis and beta-lactamase-mediated activation of a cephalosporin-taxol prodrug

BACKGROUND

Enzyme-activatable prodrugs in conjunction with antibody-enzyme fusion proteins may enhance the anti-tumor efficacy of antibodies and reduce the toxic side effects of conventional chemotherapeutics. Cephalosporins have proven to be highly versatile triggers for the enzymatic activation of such prodrugs.

RESULTS

A cephem prodrug of taxol (PROTAX) was synthesized by substituting the C-3' position of cephalothin with 2'-(gamma-aminobutyryl) taxol. Hydrolysis of PROTAX by beta-lactamase rapidly released 2'-(gamma-aminobutyryl) taxol (kcat/K(M) = (1.4 +/- 0.1) x 10(5) s-1 M-1), which yielded taxol following intramolecular displacement. PROTAX is inactive in a microtubule assembly assay in vitro but has similar activity to taxol following prolonged activation with beta-lactamase. PROTAX is approximately 10-fold less toxic than taxol against SK-BR-3 breast tumor cells in vitro but has activity approaching that of taxol following prolonged activation with a fusion protein comprising beta-lactamase fused to a tumor-targeting antibody fragment.

CONCLUSIONS

Tubulin polymerization activity is abolished and cytotoxicity is reduced in the PROTAX prodrug compared to taxol. Activation of PROTAX by beta-lactamase followed by self-immolation restores the activity of PROTAX to that of free taxol.

Assessment of self-report in HIV surveillance: a pilot study

The basis of HIV exposure category classification was investigated among selected cases of newly diagnosed HIV infection. Questionnaires seeking specific information on patient-reported exposure to HIV were forwarded to doctors who had requested the HIV antibody test for patients who met the study sample criteria. The cases of interest were those newly diagnosed between 1 January and 31 October 1991 and notified to state and territory health authorities as having been attributed to exposures to HIV other than male homosexual contact or receipt of blood, blood products or tissue. A total of 158 questionnaires was forwarded and 59 per cent were returned. Among the returned questionnaires included in the study sample, exposure to HIV on the original notification to the health authority was given as injecting drug use (8 per cent, 3 of 37), heterosexual contact (46 per cent, 17 of 37), or unavailable (46 per cent, 17 of 37). A clear basis for HIV exposure category classification was provided on the questionnaires for 70 per cent (7 of 10) of cases among women, whereas among men whose infection was attributed to heterosexual contact, a basis for exposure category classification was specified for only 43 per cent (10 of 23) of cases. Although the study was limited by the low response rate, use of the questionnaire provided a relatively simple means for assessing self-reported HIV exposure history.

Radioimmunoassay and enzymeimmunoassay of plasma progesterone as monitors of progesterone sponge treatment in ewes

The daily plasma progesterone (P) concentrations achieved during insertion of P (750 mg) sponges into two groups of ewes were examined. Group I received prostaglandin (PG) treatment, which was required to suppress the P production (to levels of < 0.3 ng hormone/ml plasma) from the corpora lutea (CL) of a previous superovulation treatment, following which these Group I ewes and the anestrous Group II ewes were sponge treated. Radioimmunoassay (RIA) and enzymeimmunoassay (EIA) were used to measure the P levels in both groups. Progesterone (750 mg) sponges with and without citric acid impregnation were inserted into all the ewes for 12 days (d). Citric acid lowered the P levels reaching the plasma from the sponges, but it did not mask the characteristic profile (during the treatments) determined by the states of the ewes (single PG and double PG injected, Group I or in the anestrous Group II). The plasma P levels in Group I and II ewes rose to at least 7.0 ng/ml at intervals during treatment. The duration and magnitude of the P concentrations in the plasma were higher in the single PG compared with the double PG ewes during sponge insertion in Group I. The anestrous Group II ewes showed two major peaks (Day 1, P<0.01 and Days 11 to 12, P<0.05) during sponge treatment. A P level > 2.0 ng/ml was maintained over the entire treatment in the single PG and in the anestrous hormone-treated ewes, and was of shorter duration (7 d) in the double PG-treated animals. These endogenous patterns in P profiles of the ewes indicate that the hormone level during sponge insertion varies in magnitude and duration, parameters determined by the physiological/endocrinological state of the ewes at the start of the treatment. The EIA correlated significantly (P<0.001) with the RIA for the measurement of P concentration, when analyzed daily on an individual animal basis.

Relationship between serum lactate and ionized calcium in open-heart surgery

We studied 16 patients undergoing open-heart surgery and heart-lung bypass, to examine the relationship between ionized calcium and lactate. Blood was sampled at successive stages of the operation for measurement of ionized and total calcium, lactate, blood gases, pH, hematocrit, and other constituents. We found that correlations between ionized calcium and lactate were positive and statistically significant (p less than 0.05), both among and within patients. The linear regression of ionized calcium on lactate remained highly significant (p less than 0.0001) after adjustment for variability among patients and across operative stages as well as after correction for pH and hemodilution. The significant regressions between calcium and lactate, both before and after administration of calcium, indicate a relationship for calcium and lactate in patients undergoing open-heart surgery.

Relationship between serum lactate and ionized calcium in open-heart surgery

We studied 16 patients undergoing open-heart surgery and heart-lung bypass, to examine the relationship between ionized calcium and lactate. Blood was sampled at successive stages of the operation for measurement of ionized and total calcium, lactate, blood gases, pH, hematocrit, and other constituents. We found that correlations between ionized calcium and lactate were positive and statistically significant (p less than 0.05), both among and within patients. The linear regression of ionized calcium on lactate remained highly significant (p less than 0.0001) after adjustment for variability among patients and across operative stages as well as after correction for pH and hemodilution. The significant regressions between calcium and lactate, both before and after administration of calcium, indicate a relationship for calcium and lactate in patients undergoing open-heart surgery.