Adjunctive pascolizumab in rifampicin-susceptible pulmonary tuberculosis: proof-of-concept, partially-randomised, double-blind, placebo-controlled, dose-escalation trial

BACKGROUND

Interleukin-4 (IL-4), increased in tuberculosis infection, may impair bacterial killing. Blocking IL-4 confers benefit in animal models. We evaluated safety and efficacy of pascolizumab (humanised anti-IL-4 monoclonal antibody) as adjunctive tuberculosis treatment.

METHODS

Participants with rifampicin-susceptible pulmonary tuberculosis received a single intravenous infusion of pascolizumab or placebo; and standard 6-month tuberculosis treatment. Pascolizumab dose increased in successive cohorts: [1] non-randomised 0.05 mg/kg (n = 4); [2] non-randomised 0.5 mg/kg (n = 4); [3] randomised 2.5 mg/kg (n = 9) or placebo (n = 3); [4] randomised 10 mg/kg (n = 9) or placebo (n = 3). Co-primary safety outcome was study-drug-related grade 4 or serious adverse event (G4/SAE); in all cohorts (1-4). Co-primary efficacy outcome was week-8 sputum culture time-to-positivity (TTP); in randomised cohorts (3-4) combined.

RESULTS

Pascolizumab levels exceeded IL-4 50% neutralising dose for 8 weeks in 78-100% of participants in cohorts 3-4. There were no study-drug-related G4/SAEs. Median week-8 TTP was 42 days in pascolizumab and placebo groups (p = 0.185). Rate of TTP increase was greater with pascolizumab (difference from placebo 0.011 [95% Bayesian credible interval 0.006 to 0.015] log10TTP/day.

CONCLUSIONS

There was no evidence to suggest blocking IL-4 was unsafe. Preliminary efficacy findings are consistent with animal models. This supports further investigation of adjunctive anti-IL-4 interventions for tuberculosis in larger phase 2 trials.

Initial Report of a Randomized Trial Comparing Conventional vs. Novel Treatment Planning Technique to Ameliorate Immunosuppression from Lung SBRT

PURPOSE/OBJECTIVE(S)

SBRT is highly effective against early-stage non-small cell lung cancer. Radiation Therapy (RT) is known to modulate the immune system and contribute to the generation of anti-tumor T cells and stimulate T cell infiltration into tumors. However, this anti-tumor activity is offset by radiation-induced immunosuppression (RIIS) which results in lower tumor control and survival. Lymphocytes are highly radiosensitive and RIIS means destroying existing as well as newly created cytotoxic and helper T lymphocytes. We hypothesized that optimizing RT treatment planning by considering circulating blood and lymphatics as a critical Organ at Risk (OAR) may mitigate RIIS.

MATERIALS/METHODS

We conducted an IRB approved NCI funded clinical trial for 50 early-stage lung cancer patients treated with SBRT alone, from 2020 to 2023, to investigate the ability to reduce RIIS by reducing dose to circulating blood and lymphatics with the aid of a predictive algorithm. All SBRT plans adhered to treatment parameters from RTOG 0813 (central) or RTOG 0915 (peripheral). Patients were randomized to two arms: experimental optimization for RIIS (to reduce dose to blood and lymphatic rich organs) versus standard SBRT planning (without optimization for RIIS). Peripheral blood samples were collected at baseline, end of Tx, 4 weeks and 6 months post Tx. Patients with baseline absolute lymphocyte counts (ALC) less than 0.5x109 cells/L were ineligible for the trial. Data acquired for all blood cell types as well as lymphocyte sub populations CD3+, CD4+, CD8+, CD19+, CD56+. Two sample t-test was used to determine the statistical significance between the cohorts at the time points.

RESULTS

The standard arm had an ALC reduction of 28% at one week post Tx and a nadir at 4 weeks with a 34% reduction. Absolute percentage reductions in ALC from baseline in the optimized arm compared to the standard arm are: end of treatment point (13%, p = 0.03), 4 weeks (12%, p = 0.08), 6 months (15%, p = 0.1), and all three time points together 13% (p = 0.001). ALC recovery appears to be faster in the optimized arm. Radiation induced suppression of all blood cell types are also reduced in the optimized arm with respect to standard arm (relative percentages): ALC (34%), WBC (47%), RBC (46%), platelets (40%), monocytes (100%), and neutrophils (62%) at 4-week mark. Average percentage reductions on integral doses, and V5 (volume receiving a 5 Gy dose) of optimized compared to standard plans are: aorta: 26%, 41% heart: 8%, 33%, vena cava: 32%, 52%, T spine: 51%, 81%, lymph nodes: 35%, 57%, total lung- ITV: 1.6%, 1%, body: 10%, 14%.

CONCLUSION

For the first time, we have shown that it is possible to reduce RIIS in a statistically significant manner, compared to standard of care, via optimized RT planning using a predictive model. This has implications in increasing the efficacy of immunotherapy by preserving the existing tumor reactive T cells in the immune system to enhance anti-tumor activity, and in reducing hospitalizations and improving survival.

Technology-enabled virtual ward for COVID management of the elderly and immunocompromised in Singapore: a descriptive cohort

BACKGROUND

To address the hospital bed demand for Delta and Omicron surges in Singapore, the National University Health System (NUHS) developed a COVID Virtual Ward to relieve bed pressures on its three acute hospitals-National University Hospital, Ng Teng Fong General Hospital, Alexandra Hospital. To serve a multilingual population, the COVID Virtual Ward featuring protocolized teleconsultation of high-risk patients, use of a vital signs chatbot, supplemented by home visits where necessary. This study aims to evaluate the safety, outcomes and utilisation of the Virtual Ward as a scalable response to COVID-19 surges.

METHODS

This is a retrospective cohort study of all patients admitted to the COVID Virtual Ward between 23 September to 9 November 2021. Patients were defined as "early discharge" if they were referred from inpatient COVID-19 wards and "admission avoidance" if they were referred directly from primary care or emergency services. Patient demographics, utilisation measures and clinical outcomes were extracted from the electronic health record system. The primary outcomes were escalation to hospital and mortality. Use of the vital signs chatbot was evaluated by examining compliance levels, need for automated reminders and alerts triggered. Patient experience was evaluated using data extracted from a quality improvement feedback form.

RESULTS

238 patients were admitted to the COVID Virtual Ward from 23 September to 9 November, of whom 42% were male, 67.6% of Chinese ethnicity. 43.7% were over the age of 70, 20.5% were immunocompromised, and 36.6% were not fully vaccinated. 17.2% of patients were escalated to hospital and 2.1% of patients died. Patients who were escalated to hospital were more likely to be immunocompromised or to have a higher ISARIC 4C-Mortality Score. There were no missed deteriorations. All patients received teleconsults (median of 5 teleconsults per patient, IQR 3-7). 21.4% of patients received home visits. 77.7% of patients engaged with the vital signs chatbot, with a compliance rate of 84%. All patients would recommend the programme to others in their situation.

CONCLUSIONS

Virtual Wards are a scalable, safe and patient-centered strategy to care for high risk COVID-19 patients at home.

TRIAL REGISTRATION

NA.

The Case for Intermittent Carbapenem Dosing in Stable Haemodialysis Patients

Purpose: Antimicrobial resistant infections are common in patients on haemodialysis, often needing long courses of carbapenems. This results in a longer hospital stay and risk of iatrogenic complications. However, carbapenems can be given intermittently to allow for earlier discharge. We aim to describe the clinical outcomes of intermittent versus daily meropenem in stable, intermittently haemodialysed patients. Methods: In total, 103 records were examined retrospectively. Data collected include demographics, clinical interventions and outcomes such as hospital length of stay (LOS), 30-day readmission rates and adverse events. Findings: Mean age 61.6 ± 14.2 years, 57.3% male. Most common bacteria cultured were Klebsiella pneumoniae (16.5%). The most common indication was pneumonia (27.2%). Mean duration of therapy on meropenem was 12.4 ± 14.4 days; eight patients needed more than 30 days of meropenem. In total, 55.3% did not have intervention for source control; 86.4% received daily dosing of meropenem; 7.8% patients received intermittent dosing of meropenem only, and 5.8 patients received both types of dosing regimens. LOS of the index admission was shorter for the intermittent arm (15.5 ± 7.6 days versus daily: 30.2 ± 24.5 days), though 30-day readmission was higher (50% versus daily: 38.2%). Implications: We recommend further rigorous randomised controlled trials to investigate the clinical utility of intermittent meropenem dosing in patients on stable haemodialysis.

Epidemiology and risk factors for invasive fungal disease in liver transplant recipients in a tertiary transplant center

BACKGROUND

Invasive fungal disease (IFD) in liver transplant recipients causes significant morbidity and mortality. We aim to describe institutional epidemiology and risk factors for IFD in the liver transplant population.

METHODS

We conducted a retrospective cohort study of all adult liver transplant recipients in our institution from 2005 to October 2015 to describe the epidemiology of patients with proven and probable IFD according to the European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria. To determine risk factors for IFD, a case-control study was also conducted. Cases were defined as liver transplant recipients with proven or probable IFD, and controls were defined as liver transplant recipients without IFD. Each case was matched to two controls by age (±10 years of age), gender, and time of transplant (within one year of the case).

RESULTS

28/554 (5.1%) patients developed IFD. Candidiasis (n = 11; 39.3%), Aspergillosis (n = 10; 35.7%), and Cryptococcosis (n = 3; 10.7%) were the most common fungal infections in the proven and probable IFD groups. Mold infections occurred in 13 (46.4%) cases. Reoperation, roux-en-y anastomosis, and massive intraoperative transfusion of ≥40 units of cellular blood products were major risk factors for IFD in the multivariate analysis.

CONCLUSION

Candida and Aspergillus are the most common causes of IFD in liver transplantation in our center. There is significant overlap in risk factors for such infections post-transplantation. In our cohort, critically ill patients with complicated perioperative course seem to predispose them to mold infections post-transplantation, but larger studies are required to better delineate risk factors for mold infection as well as determine the efficacy and optimal duration of mold prophylaxis in liver transplantation. With increasing echinocandin use for antifungal prophylaxis, it is also important to monitor for emerging antifungal resistance.

Responding to COVID-19: how an academic infectious diseases division mobilized in Singapore

BACKGROUND

On January 30, COVID-19 was declared a Public Health Emergency of International Concern-a week after Singapore's first imported case and 5 days before local transmission. The National University Hospital (NUH) is Singapore's third largest hospital with 1200 beds, heavy clinical workloads, and major roles in research and teaching.

MAIN BODY

With memories of SARS still vivid, there was an urgent requirement for the NUH Division of Infectious Diseases to adapt-undergoing major reorganization to face rapidly changing priorities while ensuring usual essential services and standards. Leveraging on individual strengths, our division mobilized to meet the demands of COVID-19 while engaging in high-level coordination, strategy, and advocacy. We present our experience of the 60 days since the nation's first case. During this time, our hospital has managed 3030 suspect cases, including 1300 inpatients, 37 confirmed cases, and overseen 4384 samples tested for COVID-19.

CONCLUSION

Complex hospital adaptations were supported by an unprecedented number of workflows and coordination channels essential to safe and effective operations. The actions we describe, aligned with international recommendations and emerging evidence-based best practices, may serve as a framework for other divisions and institutions facing the spread of COVID-19 globally.

Abstract P1-08-05: A phase I trial of chemotherapy followed by infusions of activated T cells armed with anti-CD3 and anti-HER2 bispecific antibody for stage III, Her2+ or Her2- breast cancer

Background: The balance in the immune system between immune surveillance and tolerance is known to be associated with the prognosis of breast cancer patients. The aim of this phase I study was to assess the safety of anti-CD3 x anti-HER2Bi bispecific antibody targeted (BAT) activated T cells (TC) in high risk breast cancer patients. The BAT T-cells exhibit anti-HER2 cytotoxicity, proliferate, and secrete immunokines upon tumor engagement.

Methods: High risk adjuvant breast cancer patients were recruited and completed standard adjuvant chemotherapy. BATs were produced by stimulating peripheral blood mononuclear cells (PBMC) obtained by leukapheresis; collected TC were then activated with anti-CD3 monoclonal antibody and expanded in IL-2 for 12-14 days. TC were armed with bispecific antibody and cryopreserved until used. Groups of 3 patients received 20, 40, 80 or 160 x 109 BATs per infusion twice a week for four weeks. All patients were treated at Roger Williams Medical Center.

Results: Nine patients were accrued and all had N3 disease. Eight of 9 patients were ER positive; 2 of 9 were HER2 overexpressing. The median OS has not reached as five of nine patients are still alive. OS range from 14.3 to 154.7 months (as December 11, 2016). Five out of the five patients who are alive have no evidence of disease and 1 patient had a secondary primary that has been successfully treated and she has no evidence of disease. It was feasible to grow up to 160 x 109 BATs and this dose level was tolerable without any cell-based dose limiting toxicities. BATs persisted in the blood for at least a week. BAT infusions induce cellular anti-tumor responses and cytokine responses.

Conclusion: Targeting HER2 positive and negative tumors induced cytotoxic anti-tumor responses, increases in Th1 cytokines and IL-12 serum levels. The prolonged survival in a high risk population suggests that BAT infusions provided a clinical benefit. These results are being confirmed in a phase II trial for metastatic breast cancer.

Citation Format: Dillon P, Rathore R, Thakur A, Colvin G, Kouttab N, Lum L. A phase I trial of chemotherapy followed by infusions of activated T cells armed with anti-CD3 and anti-HER2 bispecific antibody for stage III, Her2+ or Her2- breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-08-05.

Chemical Disruption of Wnt-dependent Cell Fate Decision-making Mechanisms in Cancer and Regenerative Medicine

Cell-to-cell signaling molecules such as the Wnt proteins that directly influence the expression of cell-type specific transcriptional programs are essential for tissue generation in metazoans. The mechanisms supporting cellular responses to these molecules represent potential points of intervention for directing cell fate outcomes in therapeutic contexts. Small molecules that modulate Wnt-mediated cellular responses have proven to be powerful probes for Wnt protein function in diverse biological settings including cancer, development, and regeneration. Whereas efforts to develop these chemicals as therapeutic agents have dominated conversation, the unprecedented modes-of-action associated with these molecules and their implications for drug development deserve greater examination. In this review, we will discuss how medicinal chemistry efforts focused on first in class small molecules targeting two Wnt pathway components--the polytopic Porcupine (Porcn) acyltransferase and the cytoplasmic Tankyrase (Tnks) poly-ADP-ribosylases--have contributed to our understanding of the druggable genome and expanded the armamentarium of chemicals that can be used to influence cell fate decision-making.

Reviewing the development, evidence base, and application of the revised dengue case classification

With the example of dengue, an evidence-based approach to prospectively develop a case classification is described, gathering evidence for identifying strength and weaknesses of the existing model, collecting new data describing the disease as it occurs globally, further developing a new model that can be applied in practice and field testing the newly developed model in comparison to the previous model. For each step in this process, the highest available level of evidence has been applied. This process has been initiated by the World Health Organization’s (WHO) Special Programme for Research and Training in Tropical Diseases (TDR) and WHO’s Department for Control of Neglected Tropical Diseases (NTD), developing the following for dengue. Since the early 1970s, dengue has been classified into dengue fever, dengue haemorrhagic fever grades I and II and dengue shock syndrome grades III and IV (DF/DHF/DSS). However, in recent years, a growing number of dengue clinicians have questioned the shortcomings of this scheme. The issues have revolved around the complexity of confirming DHF in clinical practice, misclassifying severe cases as DF, and the emphasis on haemorrhage rather than plasma leakage as the underlying problem in most severe dengue cases. Step 1: A systematic literature review highlighted the shortcomings of the DF/DHF/DSS scheme: (1) difficulties in applying the criteria for DHF/DSS; (2) the tourniquet test has a low sensitivity for distinguishing between DHF and DF; and (3) most DHF criteria had a large variability in frequency of occurrence. Step 2: An analysis of regional and national dengue guidelines and their application in the clinical practice showed a need to re-evaluate and standardize guidelines as the actual ones showed a large variation of definitions, an inconsistent application by medical staff, and a lack of diagnostic facilities necessary for the DHF diagnosis in frontline services. Step 3: A prospective cohort study in seven countries, confirmed the difficulties in applying the DF/DHF/DSS criteria even in tertiary care hospitals, that DF/DHF/DSS do not represent levels of disease severity and that a clear distinction between severe dengue (defined by plasma leakage and/or severe haemorrhage, and/or organ failure) and (non-severe) dengue can be made using highly sensitive and specific criteria. In contrast, the sub-grouping of (non-severe) dengue into two further severity levels was only possible with criteria that gave approximately 70% sensitivity and specificity. Step 4: Three regional expert consensus groups in the Americas and Asia concluded that ‘dengue is one disease entity with different clinical presentations and often with unpredictable clinical evolution and outcome’ and that, revising the results of Step 3, DF/DHF/DSS is not related to disease severity. Step 5: In a global expert consensus meeting at WHO in Geneva/Switzerland the evidence collected in Steps 1–4 was reviewed and a revised scheme was developed and accepted, distinguishing: dengue with or without warning signs and severe dengue; the further field testing and acquisition of further prospective evidence of the revised scheme was recommended. Step 6: In 18 countries, the usefulness and applicability of the revised classification compared to the DF/DHF/DSS scheme were tested showing clear results in favour of the revised classification. Step 7: Studies are under way on the predictive value of warning signs for severe dengue and on criteria for the clinical diagnosis of dengue which will complete the evidence foundation of the revised classification. The analysis has shown that the revised dengue case classification is better able to standardize clinical management, raise awareness about unnecessary interventions, match patient categories with specific treatment instructions, and make the key messages of patient management understandable for all health care staff dealing with dengue patients. Furthermore, the evidence-based approach to develop prospectively the dengue case classification could be a model approach for other disease classifications.

Abstract P4-06-06: RNAi screen of the breast cancer genome identifies KIF14 and TLN1 as genes that modulate chemosensitivity in breast cancer

We conducted a RNA-interference screen for genes whose loss-of-function enhanced doxorubicin and docetaxel chemosensitivity in a “triple-negative,” estrogen receptor negative, progesterone receptor negative, and Her2 negative (ER− PR− Her2−) breast cancer cell line, MDA-MB-231. From ranking chemosensitivity of 334 short-hairpin RNA (shRNA) MDA-MB-231 cell lines (targeting 134 genes with known somatic mutations in breast cancer), we focused on two genes, kinesin family member 14 (KIF14) and talin (TLN1) that not only enhanced chemosensitivity but also have oncogenic annotations. KIF14 has robust expression in breast cancer cells compared to normal mammary cells. TLN1 expression is important for migration of breast cancer cells. In TLN1-deficient cells, CK19 and ZO-1 are upregulated while CK14 and snail are downregulated, suggesting that TLN1 is important for the maintenance of epithelial-mesenchymal transition in MDA-MB-231 cells. KIF14 and TLN1 loss-of-function also enhanced chemosensitivity in 3 other triple negative breast cancer cell lines (HCC1937, HCC38, and Hs578T) but not in normal human mammary epithelial cells (HMECs). Examining protein-protein-interaction networks, we identified RIP2 as a target whose inhibition via SB203580 or PP2 can further enhance chemosensitization in KIF14-deficient cells. Knock-down of a number of other known protein-protein interaction partners of KIF14 and TLN1, including FAK, CIT, ARRB2, PSTPiP1, PRC1, SVIL, ITGA2B, ITGB3, VCL and PXN, do not significantly alter doxorubicin or docetaxel chemosensitivity in MDA-MB-231 cells. Mammary fat pad xenografts of KIF14- and TLN1- deficient MDA-MB-231 cells into NOD/SCID mice demonstrated significantly less tumor mass compared to control MDA-MB-231 cells after chemotherapy. Expressions of KIF14 and TLN1 from breast cancer expression arrays improve prognostic predictions compared to clinicopathological features alone. In summary, screenings for therapeutic targets using chemotherapy and genes with known somatic mutations in breast cancer not only provide a rational targeted screen, but also present possible up-front novel treatment combinations for patients with triple negative breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-06-06.

Marrow stem cell potential within a continuum

On the basis of our studies of the fluctuation of the hematopoietic stem cell phenotype with cell cycle trnsit, we hypothesize that the ability of marrow stem cells to convert to nonhematopoietic cells will also vary at different points in the cell cycle. The new biology of stem cells has an impact on many fields including developmental biology and stem cell biology and the clinical potential is enormous.

Biochemical and pharmacological criteria define two shedding activities for TRANCE/OPGL that are distinct from the tumor necrosis factor alpha convertase

A number of structurally and functionally diverse membrane proteins are released from the plasma membrane in a process termed protein ectodomain shedding. Ectodomain shedding may activate or inactivate a substrate or change its properties, such as converting a juxtacrine into a paracrine signaling molecule. Here we have characterized the activities involved in protein ectodomain shedding of the tumor necrosis factor family member TRANCE/OPGL in different cell types. The criteria used to evaluate these activities include (a) cleavage site usage, (b) response to activators and inhibitors of intracellular signaling pathways, and (c) sensitivity to tissue inhibitors of metalloproteases (TIMPs). At least two TRANCE shedding activities emerged, both of which are distinct from the tumor necrosis factor alpha convertase. One of the TRANCE sheddases is induced by the tyrosine phosphatase inhibitor pervanadate but not by phorbol esters, whereas the other is refractory to both of these stimuli. Furthermore, the pervanadate-regulated sheddase activity is sensitive to TIMP-2 but not TIMP-1, which is consistent with the properties of a membrane type matrix metalloprotease. This study provides insights into the properties of different activities involved in protein ectodomain shedding and has implications for the functional regulation of TRANCE by potentially more than one protease.

Severe upper airway obstruction in the tropics requiring intensive care

BACKGROUND

The clinical profile of severe upper airway obstruction, a challenging acute pediatric emergency, has not been extensively documented in the developing nations of the tropics.

METHODS

The diagnostic categories, severity of illness and outcome from 63 episodes of severe upper airway obstruction in 56 children admitted to the Pediatric Intensive Care Unit between January 1994 and December 1999 were reviewed. Outcome variables studied included requirement for ventilation, mortality and complications. Severity of illness was determined with the Pediatric Risk of Mortality (PRISM) II score.

RESULTS

Viral croup (29%) was the most common diagnosis, followed by mediastinal malignancy (13%), bacterial tracheitis (11%) and Pierre Robin syndrome (11%). There were no admissions for acute epiglottitis. Thirty episodes (48%) required ventilation for a median duration of 4.0 days. Bacterial tracheitis (100%) and subglottic stenosis (100%) were the most likely diagnoses requiring ventilation. Difficulty in intubation was encountered in 13 episodes (43%) involving, in particular, patients with bacterial tracheitis (83%; P = 0.006). Only two patients required a tracheostomy. The overall mortality was 11%. The PRISM score for all categories was generally low (mean 10.3 +/- 1.0; median 9.0). Non-survivors had a significantly higher PRISM II score than survivors (27.4 +/- 9.7 vs 8.1 +/- 4.9, respectively; P = 0.002) and were more likely to include children with bacterial tracheitis and mediastinal malignancy.

CONCLUSIONS

There is marked heterogeneity in the causes of upper airway obstruction in the tropics with viral croup remaining the most common. A significant proportion required ventilation, but outcome is generally favorable, except in those with bacterial tracheitis and mediastinal malignancy.

Sepsis, severe sepsis and septic shock in paediatric multiple organ dysfunction syndrome

OBJECTIVES

To determine the association between severity of sepsis with outcome and severity of illness in children with multiple organ dysfunction syndrome (MODS).

MATERIALS

Four hundred and ninety-five consecutive paediatric intensive care unit (PICU) admissions were analysed. multiple organ dysfunction syndrome was defined as simultaneous dysfunction of >/= 2 organ system and sepsis by the American College of Chest Physicians and Society of Critical Care Medicine Consensus Conference definition.

RESULTS

Eighty-four patients developed MODS. The incidence of sepsis, severe sepsis and septic shock in these patients was 10.7%, 23.8% and 17.9%, respectively. Worsening categories of sepsis were associated with: (1) a higher mean admission Paediatric Risk of Mortality (PRISM II): 36.6 +/- 25.9, 56.8 +/- 32.1 and 73.6 +/- 28.5%, respectively (P = 0. 005), (2) a larger number of organ dysfunctions: mean MODS index of 37%, 46% and 58%, respectively (P = 0.007), and (3) a higher mortality: 22.2%, 65% and 80%, respectively (P = 0.03).

CONCLUSION

Presence of sepsis, severe sepsis and septic shock was associated with an increasing severity of illness, increased number of organ dysfunctions and a distinct risk of mortality among critically ill children.

Evidence for a role of a tumor necrosis factor-alpha (TNF-alpha)-converting enzyme-like protease in shedding of TRANCE, a TNF family member involved in osteoclastogenesis and dendritic cell survival

Tumor necrosis factor (TNF)-related activation-induced cytokine (TRANCE), a member of the TNF family, is a dendritic cell survival factor and is essential for osteoclastogenesis and osteoclast activation. In this report we demonstrate (i) that TRANCE, like TNF-alpha, is made as a membrane-anchored precursor, which is released from the plasma membrane by a metalloprotease; (ii) that soluble TRANCE has potent dendritic cell survival and osteoclastogenic activity; (iii) that the metalloprotease-disintegrin TNF-alpha convertase (TACE) can cleave immunoprecipitated TRANCE in vitro in a fashion that mimics the cleavage observed in tissue culture cells; and (iv) that in vitro cleavage of a TRANCE ectodomain/CD8 fusion protein and of a peptide corresponding to the TRANCE cleavage site by TACE occurs at the same site that is used when TRANCE is shed from cells into the supernatant. We propose that the TRANCE ectodomain is released from cells by TACE or a related metalloprotease-disintegrin, and that this release is an important component of the function of TRANCE in bone and immune homeostasis.

Intracellular maturation of the mouse metalloprotease disintegrin MDC15

Metalloprotease disintegrins are a family of membrane-anchored glycoproteins that play a role in fertilization, myoblast fusion, neuronal development, and cleavage of the membrane-anchored cytokine tumor necrosis factor-alpha. Here, we report the cloning and cDNA sequencing of the mouse metalloprotease disintegrin MDC15 and an analysis of its processing in the secretory pathway. A notable difference between mMDC15 and its putative human orthologue (hMDC15, metargidin) is the presence of the peptide sequence TDDC instead of the RGDC found in the disintegrin domain of hMDC15. In a Western blot analysis the majority of mMDC15 was found to lack the pro-domain in all mouse tissues examined. Pulse-chase experiments in transiently transfected COS-7 cells suggest that mMDC15 is processed by a pro-protein convertase in a late Golgi compartment, since (i) addition of brefeldin A or monensin blocks pro-domain removal, (ii) all detectable processed mMDC15 is endoglycosidase H -resistant, and (iii) a recombinant soluble form of the trans-Golgi network pro-protein convertase furin can mimic mMDC15 processing in vitro. Cell-surface trypsinization revealed that more than half of mature mMDC15 is intracellular. Immunolocalization provided evidence for a strong perinuclear accumulation in a region resembling the trans-Golgi network and/or endosomal compartments. This study provides the first characterization of the intracellular processing of a metalloprotease disintegrin, and highlights the potential role of pro-protein convertases in removal of the inhibitory pro-domain. These results further suggest possible intracellular functions for mMDC15, such as in protein maturation, in addition to a potential role in cell-surface proteolysis or cell adhesion.

Accuracy of physiologic deadspace measurement in intubated pediatric patients using a metabolic monitor: comparison with the Douglas bag method

OBJECTIVE

To evaluate the accuracy of physiologic deadspace (VD/VT) measurement, using a metabolic monitor.

DESIGN

Prospective collection of data.

SETTING

University-affiliated children's hospital with a 51-bed critical care area.

PATIENTS

Infants and children who were sedated and paralyzed and were receiving mechanical ventilation through a cuffed endotracheal tube.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Mixed expired carbon dioxide tension (PECO2) was measured. With the Douglas bag method, mixed expired gas was collected over 15 mins and was analyzed. With the metabolic monitor, FECO2 was measured for 15 mins and the results were averaged. The PECO2 was calculated by multiplying FECO2 by the barometric pressure. The PaCO2 was measured simultaneously. The PECO2 was corrected for the compressible volume in the ventilator circuit. All gas volumes were corrected for body temperature, pressure, and water vapor pressure. The physiologic deadspace/tidal volume ratio (VD/VT) was calculated for both techniques using the Enghoff modification of the Bohr equation. The accuracy of the VD/VT measured, by using the metabolic monitor, was assessed by comparing this measurement against the VD/VT measured by the Douglas bag method. This comparison was done by simple linear regression and correlation and by bias analysis (Bland and Altman method). The magnitude of compressible volume expressed as a fraction of the tidal volume delivered by the ventilator was compared with the error in VD/VT expressed as the difference between the uncorrected and corrected VD/VT. Sixteen paired measurements were made in 12 children. The VD/VT measured by the metabolic monitor correlated well with the VD/VT measured by the Douglas bag method (r2 = .99; p < .0001). There was no correlation between the bias of VD/VT and the average VD/VT. As the magnitude of compressible volume increased, the error in VD/VT increased (r2 =.61; p < .001).

CONCLUSIONS

The VD/VT can be measured reliably and accurately in intubated pediatric patients using a metabolic monitor. The metabolic monitor method is a convenient and simple alternative to the standard Douglas bag method.

Cloning and initial characterization of mouse meltrin beta and analysis of the expression of four metalloprotease-disintegrins in bone cells

Here we report the cloning and initial biochemical characterization of the mouse metalloprotease/disintegrin/cysteine-rich (MDC) protein meltrin beta and the analysis of the mRNA expression of four MDC genes (meltrin alpha, meltrin beta, mdc9, and mdc15) in bone cells, including osteoclasts and osteoblasts. Like most other MDC proteins, the predicted meltrin beta protein consists of a signal sequence, prodomain, metalloprotease domain with a predicted catalytic site, disintegrin domain, cysteine-rich region, epidermal growth factor repeat, transmembrane domain, and cytoplasmic domain with putative signaling motifs, such as potential SH3 ligand domains. Northern blot analysis indicates that meltrin beta is widely expressed, with the highest expression in bone, heart, and lung. RNase protection studies revealed expression of all four MDC genes analyzed here in osteoblasts, whereas only mdc9 and mdc15 mRNAs were detectable in osteoclast-like cells generated in vitro. Treatment of primary osteoblasts with 10 nM calcitriol increased meltrin beta expression more than 3-fold, and both meltrin alpha and meltrin beta expression is apparently regulated in a differentiation-associated manner in a mouse osteoblastic cell line, MC3T3E1. Collectively, these results suggest that meltrin alpha and meltrin beta may play a role in osteoblast differentiation and/or function but are not likely to be involved in osteoclast fusion.

Evidence for distinct serine protease activities with a potential role in processing the sperm protein fertilin

The guinea pig sperm protein fertilin (previously termed PH-30) plays an important role in sperm-egg fusion, and was the first recognized membrane-anchored metalloprotease/disintegrin protein. Fertilin is a heterodimeric glycoprotein which undergoes at least two distinct proteolytic processing steps. Fertilin alpha is processed first, in the testis, whereas fertilin beta is processed separately during sperm maturation in the epididymis. The final processing of fertilin beta occurs immediately adjacent to its predicted integrin ligand domain, and exposes an epitope recognized by a fusion blocking monoclonal antibody. Here, we demonstrate that one or more serine protease activities associated with testicular sperm can process fertilin beta in vitro in a fashion that closely mimics the processing pattern observed in vivo during epididymal sperm maturation. In contrast, several proteases that were added to testicular sperm did not mimic the pattern observed in vivo. These findings raise the intriguing possibility that a fertilin beta converting protease(s) active in vivo may originate from sperm, instead of from the epididymal epithelium. Further, we show that fertilin alpha is most likely processed intracellularly in the secretory pathway based on three observations: (i) only processed fertilin alpha, but not the precursor pro-alpha can be cell-surface biotinylated; (ii) some processed fertilin alpha is sensitive to endoglycosidase H, suggesting cleavage occurs prior to the medial Golgi apparatus; (iii) a reanalysis of the N-terminus of processed fertilin alpha showed that the proteolytic cleavage site is next to four arginine residues, a consensus sequence for intracellular subtilysin type pro-protein convertases. The N-terminal sequence analysis further showed that processed fertilin alpha contains an intact membrane anchored disintegrin domain, and not a truncated disintegrin domain as reported previously (Blobel, C. P., Wolfsberg, T. G., Turck, C. W., Myles, D. G., Primakoff, P., and White, J. M., Nature 356, 248-252, 1992). Proteolytic processing is thought to play an important role in regulating the function of fertilin, and the present study represents a first step toward a better understanding of protease activities involved in the maturation of fertilin, and potentially other sperm surface proteins.

Differential allelic expression of lactoproteins: a model to study transcriptional regulation

The importance of transcriptional control of gene expression has been documented in relation to several genetic defects in man. Mutations in the promoter region of genes have been shown to be responsible for defects which are characterized by over or under expression of genes. Genetic polymorphisms of the milk protein genes, and their high level of tissue specific expression during lactation, represent a suitable system for studying regulation of gene expression. Quantification of the allele specific protein products has demonstrated unequal allelic contribution in the expression of the beta lactoglobulin (beta-LG) alleles A and B. The DNA sequence analysis of the beta-LG promoter revealed allele specific polymorphisms related to the coding region genotypes.

Metargidin, a membrane-anchored metalloprotease-disintegrin protein with an RGD integrin binding sequence

Cellular disintegrins are a family of membrane-anchored proteins with structural homology to snake venom metalloproteases and disintegrins. We report here the cDNA cloning and initial biochemical characterization of the first cellular disintegrin protein with an RGD sequence in its disintegrin domain, which we propose to name metargidin (for metalloprotease-RGD-disintegrin protein). The domain organization of metargidin is identical with that of previously reported members of the cellular disintegrin family, comprising (i) a pro- and a metalloprotease domain including a zinc-binding consensus motif, (ii) a disintegrin domain containing the RGD motif, (iii) a cysteine-rich domain, (iv) an epidermal growth factor-like domain, (v) a hydrophobic transmembrane domain, and (vi) a cytoplasmic tail with proline-rich sequences that could act as potential SH3 ligands. Antibodies raised against the cytoplasmic tail of metargidin recognize a glycoprotein of 110 kDa in MDA-MB-468 mammary epithelial carcinoma cells, which can be cell surface-biotinylated, indicating its localization in the plasma membrane. A second protein of 56 kDa co-immunoprecipitates with metargidin, suggesting that it is part of a protein complex. These features are consistent with a model in which metargidin is an integrin ligand which, as a transmembrane protein, might function in cell-cell adhesion and/or signaling.

Clinical course and outcome of patients with Hodgkin's disease who progress after autologous transplantation

Twenty-six of fifty-eight patients undergoing autologous bone marrow transplantation (autoBMT) or peripheral stem cell transplantation (PSCT) for Hodgkin's disease had progression of lymphoma (Hodgkin's or non-Hodgkin's) during the course of their follow-up. The majority of progressions, 81% (21/26), occurred within the first year of transplant; 12% (3/26) occurred at three years or more. Three patients developed a non-Hodgkin's lymphoma; all B-cell tumors primarily involving the gastrointestinal tract. The majority of patients (23/26) received at least one therapy after progression and 65% (17/26) of patients received multiple therapies. One patient who received a second BMT is alive without evidence of disease at 49 months following the second autologous BMT. The median survival for the entire group is 11 months. Forty-six percent (12/26) of patients survived more than one year and twenty-three percent (6/26) survived more than two years after disease progression. Post-progression survival is significantly related to time to progression.

A 70-amino acid zinc-binding polypeptide fragment from the regulatory chain of aspartate transcarbamoylase causes marked changes in the kinetic mechanism of the catalytic trimer

Interaction between a 70-amino acid and zinc-binding polypeptide from the regulatory chain and the catalytic (C) trimer of aspartate transcarbamoylase (ATCase) leads to dramatic changes in enzyme activity and affinity for active site ligands. The hypothesis that the complex between a C trimer and 3 polypeptide fragments (zinc domain) is an analog of R state ATCase has been examined by steady-state kinetics, heavy-atom isotope effects, and isotope trapping experiments. Inhibition by the bisubstrate ligand, N-(phosphonacetyl)-L-aspartate (PALA), or the substrate analog, succinate, at varying concentrations of substrates, aspartate, or carbamoyl phosphate indicated a compulsory ordered kinetic mechanism with carbamoyl phosphate binding prior to aspartate. In contrast, inhibition studies on C trimer were consistent with a preferred order mechanism. Similarly, 13C kinetic isotope effects in carbamoyl phosphate at infinite aspartate indicated a partially random kinetic mechanism for C trimer, whereas results for the complex of C trimer and zinc domain were consistent with a compulsory ordered mechanism of substrate binding. The dependence of isotope effect on aspartate concentration observed for the Zn domain-C trimer complex was similar to that obtained earlier for intact ATCase. Isotope trapping experiments showed that the compulsory ordered mechanism for the complex was attributable to increased "stickiness" of carbamoyl phosphate to the Zn domain-C trimer complex as compared to C trimer alone. The rate of dissociation of carbamoyl phosphate from the Zn domain-C trimer complex was about 10(-2) that from C trimer.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation of colony-forming cells, long-term culture initiating cells and CD34+ cells in apheresis products from patients mobilized for peripheral blood progenitors with different regimens

Peripheral blood progenitor cell (PBPC) populations used for transplantation were analyzed for the presence of CD34+ cells, colony-forming cells (initial CFC), and long-term culture initiating cells (LTC-IC) cultured on irradiated stroma for 5 weeks. Thirty-eight leukapheresis products were studied from 11 patients with breast cancer, 2 with non-Hodgkin's lymphoma and 1 with ovarian cancer harvested during recovery from either cyclophosphamide (CY) chemotherapy or cyclophosphamide-VP16 with G-CSF (CY-VP-G). CY-VP-G products had a threefold higher median number of mononuclear cells collected, a fivefold higher median concentration of CD34 and LTC-IC and a threefold higher concentration of initial-CFC when compared with CY products. CY-VP-G products had a significantly higher ratio of CFU-GM to BFU-E than the CY-mobilized products. Significant correlations of r = 0.89 and r = 0.68 were observed when comparing CD34 and CFC in products from CY or CY-VP-G patients, respectively. Analysis of the regression lines indicated that slopes of these regression lines were significantly different with a ratio of CD34 to initial CFC of 15:1 in the CY-VP-G products versus 5.2:1 with the CY products. These data indicate a higher cloning efficiency of the CD34+ population in the products from CY-mobilized patients. Significant correlations of r = 0.9 (CY) and r = 0.53 (CY-VP-G) were observed when the initial CD34 concentration and the LTC-IC were compared. Comparison of initial CFC with LTC-IC also showed significant correlations (r = 0.94, CY; r = 0.58, CY-VP-G) in samples from both patient groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Expansion of neutrophil precursors and progenitors in suspension cultures of CD34+ cells enriched from human bone marrow

The growth and differentiation of selected bone marrow CD34+ cells stimulated with hematopoietic growth factors in lipid cultures were evaluated to determine whether cell types that may be useful for reducing the neutropenia associated with high-dose chemotherapy (HDC) can be produced and quantitated in vitro. CD34+ cells enriched from bone marrow were cultured for up to 5 weeks in interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) with or without stem cell factor (SCF) (also termed c-kit ligand). The mixture of IL-3, GM-CSF and G-CSF resulted in an 18-fold increase in cells after 10 to 12 days of culture and a 94-fold increase after 21 days. A 3-fold increase in colony-forming unit granulocyte-macrophage (CFU-GM) was observed after 10 days of culture. The addition of SCF during the first 10 days of culture further augmented the proliferation of cell numbers to 24-fold and colony-forming cells (CFC) to 8-fold after 10 days while cell numbers increased 130-fold after 21 days. Two-color flow cytometry defined phenotypes expressing CD11b and CD15 that represented maturation stages of neutrophils. Maturation of neutrophils in these cultures could be followed by the initial appearance after 3 to 7 days of a CD15+CD11b- phenotype representing promyelocytes, which gave rise after 2 to 3 weeks to a CD15+CD11b+ phenotype representing more mature neutrophil forms (metamyelocytes to segmented neutrophils). In contrast to normal neutrophil development, only a small fraction (10 to 15%) of the culture-derived neutrophils expressed CD16. These data define the kinetics and differentiation of neutrophils and neutrophil precursors from selected CD34+ cells in liquid cultures.

Chlamydia pneumoniae respiratory infection in a child--a case report

A case of respiratory infection in a child due to Chlamydia pneumoniae is reported. The diagnosis was made by the detection of chlamydial antigen in the tracheal secretion and a significant increase in C. pneumoniae antibody titre. The infection responded well to erythromycin therapy.

Influence of cardiopulmonary bypass on water balance hormones in children

OBJECTIVE

To determine the changes in the endocrine mechanisms of fluid balance after cardiopulmonary bypass in children.

DESIGN

Prospective study; analysis of numbered plasma samples performed blind with respect to clinical data.

SETTING

Regional paediatric cardiothoracic unit.

PATIENTS

Nine patients, median age 4, range 2 to 9 years, five males. Patients under the age of 1 year were excluded because of the frequent blood sampling involved.

MAIN OUTCOME MEASURES

Plasma concentrations of atrial natriuretic peptide (ANP), arginine vasopressin, plasma renin activity, aldosterone, noradrenaline and adrenaline, and urinary concentrations of cyclic guanosine monophosphate (cGMP) as measured by radioimmunoassay.

RESULTS

After 30 minutes of cardiopulmonary bypass plasma atrial natriuretic peptide (ANP) decreased from (mean (SEM)) 151 (71) pg/ml to 52 (44) pg/ml (NS), and urinary production of its second messenger cyclic guanosine monophosphate (cGMP) decreased from 1286 (600) pmol/ml to 151 (414) pmol (p < 0.05). Other plasma concentrations of hormones studied did not change significantly although arginine vasopressin, adrenaline, and noradrenaline increased whereas aldosterone and plasma renin activity decreased. After cardiopulmonary bypass stopped there was an immediate and significant rise in plasma ANP, but within the next 24 hours plasma ANP declined significantly (p < 0.05), decreasing from 294 (49) pg/ml to 64 (29) pg/ml at 22 hours. In the postoperative period there was a significant correlation between plasma ANP and both mean fluid balance (r = 0.96, p < 0.001) and mean urine output (r = 0.97, p < 0.001). Plasma aldosterone peaked (p < 0.05) at 22 hours after operation, and argine vasopressin peaked (p < 0.05) at two hours and then declined (p < 0.05) to a trough at 24 hours. Plasma renin activity, adrenaline, noradrenaline, and urinary cGMP concentrations, and mean central venous pressure did not change significantly in the postoperative period.

CONCLUSION

The changes documented show the differing pattern of release of water balance hormones invoked by cardiopulmonary bypass. The central role of ANP is shown by its strong correlation with urinary output and its similarly strong relation to fluid balance.

The amino acid sequence of a Bacillus subtilis phosphoprotein that matches an orfY-tsr coding sequence

Bacillus subtilis contains a 30 kDa protein which was phosphorylated during late vegetative growth and sporulation. The sequence for the N-terminal 16 amino acids was found to be identical to the predicted sequence for the N-terminus of a small open reading frame, orfY, but diverged from the predicted sequence thereafter. The orfY region was resequenced and contained one less adenine residue than previously reported, resulting in an open reading frame from within orfY through the entire coding region for tsr which follows orfY. The predicted orfY-tsr amino acid sequence showed 24% identity to Escherichia coli fructose-1,6-bisphosphate aldolase. Two mutants in the tsr region had 2-5% of wild-type aldolase and the nucleotide sequences showed missense mutations. These results indicate that orfY-tsr encodes aldolase and should be renamed fba1.

Timeliness of receipt of manufacturers' new product information

In February 1988, the Pharmaceutical Manufacturers Association of Canada (PMAC) published a Code of Marketing Practices which recommends that PMAC members provide essential product information to drug information centres a minimum of two weeks prior to the marketing of new prescription drugs. A one-year study was undertaken by our Drug Information (DI) Centre to assess the compliance of PMAC companies with this guideline. Product information was mailed to our DI Centre two weeks or more prior to marketing for only 3/28 (10.7%) new prescription drugs and for none of 27 (0%) new prescription drug dosage forms or strengths. No product information was received for 10/28 (35.7%) new prescription drugs and 21/27 (77.8%) new prescription drug dosage forms or strengths. In several situations, new drugs appeared in journal advertisements or were being detailed to physicians prior to receipt of new product information. Manufacturers are encouraged to review their procedures for disseminating new product information to ensure that DI centres are notified of new product introductions at least two weeks in advance of detailing or marketing.

Marrow transplantation for children in first remission of acute nonlymphoblastic leukemia: an update

Thirty-eight children between the ages of 0.8 and 17 years with acute nonlymphoblastic leukemia in first remission induced by chemotherapy were given cyclophosphamide, total body irradiation, and bone marrow transplants from HLA-matched donors. Six patients died of pneumonia, one died of metabolic problems, and one died of chronic graft-v-host disease complications. Five patients relapsed between six months and 3.2 years after transplantation. Three of the five died of leukemia, one survives with leukemia three years after transplantation, and one survives in remission off treatment following chemotherapy for 22 months. Twenty-five survive in continuous remission from 1.7 to 8.4 years after transplantation, and the actuarial analysis shows a disease-free survival rate of 64%, with a plateau extending from 3.5 to 8.4 years. All lead normal lives.

Pneumonitis following inclusion blennorrhea

A pregnant woman and her husband had proved chlamydial genital tract infections. She gave birth to a male infant who developed inclusion blennorrhea (inclusion conjunctivitis of the newborn infant). While on topical chemotherapy for his eye disease, the infant developed pneumonitis. Chlamydiae were recovered from his sputum at a time when conjunctival specimens were sterile. This finding raises the possibility that the agent of inclusion conjunctivitis may cause systemic infections in neonates exposed during passage through an infected birth canal.