POS0479 STAT3 DEGRADERS PROTECT FROM IMMUNOFIBROTIC CHANGES IN PRECLINICAL MODELS

Background

The ubiquitin-proteasome system (UPS) is the endogenous intracellular mechanism for maintaining protein homeostasis through protein degradation and turnover. Heterobifunctional small molecules are a new class of compounds that form a ternary complex with an E3 ligase and protein of interest leading to ubiquitination and subsequent degradation of the protein of interest in a process known as Targeted Protein Degradation. This new therapeutic modality enables targeting of “undruggable” proteins such as STAT3, a transcription factor activated in immunofibrotic diseases.

Objectives

Kymera has developed heterobifunctional molecules that potently and selectively target STAT3 for degradation and elimination by the ubiquitin-proteasome pathway. The aim of these studies was to evaluate the therapeutic potential of pharmacologically removing STAT3 by targeted protein degradation in various human cell types in vitro, and to prevent the development of skin and lung fibrosis in vivo.

Methods

Dermal fibroblasts obtained from healthy and systemic sclerosis patients activated with TGF-β were analyzed for development of α-smooth muscle actin (α-SMA)-positive stress fibers and for contractility using collagen gel contraction assay. Contraction assay was also performed using human dermal smooth muscle cells. Human aortic endothelial cells (HAECs) were activated with LPS, and their adhesive properties were assessed in the microcapillary system by the ability to bind peripheral blood mononuclear cells (PBMCs) under shear stress. HAECs proliferation was induced with VEGF. THP-1 cells and CD14+ monocytes were activated with IL-6 or LPS, and secreted cytokines were assessed by CBA. PBMCs activated with LPS, IL-6, IL-21, or IL-23 alone (pSTAT3 induction), or with a combination of anti-CD3/CD38 beads and a pro-Th17 cocktail comprised of cytokines and antibodies to evaluate the development of a Th17 and Treg phenotype by flow cytometry. Cytokines were analyzed by ELISA. All cell types were pre-treated with STAT3 degraders 20h prior to experiment start. Intratracheal instillation of bleomycin was used to induce pulmonary fibrosis. Transgenic Tsk-1 mice were used as a model of spontaneous skin fibrosis.

Results

STAT3 degraders completely ablated STAT3 in all analyzed cell types with DC50 ranging from 0.25-0.8 nM. STAT3 degradation prevented TGF-β-induced formation of α-SMA-positive stress fibers in dermal fibroblasts (IC50 = 0.35nM) and 2 and 10nM degrader completely abrogated their contractility. Similarly, STAT3 degradation reduced the constitutive contractility of dermal smooth muscle cells of 13% (p<0.05, n=6). Treatment of HAECs with STAT3 degraders resulted in anti-adhesive 178±21 for LPS and 93±12 for LPS +degrader, p<0.05, n=6) and anti-proliferative 1.2±0.1 for VEGF and 0.95±0.1 for VEGF +degrader, p<0.05, n=10-11) effects. In monocyte-focused assays (CD14+ monocytes and THP-1 cells), STAT3 degradation potently and dose-dependently inhibited IL-6 and LPS-induced pSTAT3 levels and the ensuing release of MCP-1/CCL2 (24.3±3.7 for LPS and 20.2±3.2 for LPS +degrader, p<0.05, n=6). In CD4+ T lymphocytes, STAT3 degradation promoted a Treg phenotype and suppressed the development of Th17 cells. Systemic treatment in vivo showed that prophylactic STAT3 degradation (7 mg/kg twice a week, i.p.) reduced disease severity in the bleomycin-induced pulmonary fibrosis model (Ashcroft‘s score, 4.7±1.9 vs. 3.1±1.6, p<0.05, n=11). In Tsk-1 mice that show co-occurrence of spontaneous skin thickening and robust STAT3 activation, STAT3 degrader treatment (2 or 7 mg/kg twice a week, i.p.) for 7 weeks significantly reduced thickness of the skin (701±238 vs. 480±205 vs. 365±107, p<0.05, n=6-8).

Conclusion

STAT3 degraders that selectively and potently eliminate STAT3 show robust anti-inflammatory and anti-fibrotic potential in vitro and in vivo. Our results suggest that targeted protein degradation is a promising approach to modulate the STAT3 pathway, making it a novel therapeutic opportunity to treating multiple immunofibrotic diseases.

Disclosure of Interests

Przemyslaw Blyszczuk Grant/research support from: Kymera, Gabriela Kania: None declared, Elena Pachera: None declared, Filip Rolski: None declared, Amela Hukara: None declared, Vanessa Tela: None declared, Michele Mayo Employee of: Kymera, Vaishali Dixit Employee of: Kymera, Bin Yang Employee of: Kymera, Jared Gollob Employee of: Kymera, Nello Mainolfi Employee of: Kymera, Anthony Slavin Employee of: Kymera, Cedric Hubeau Employee of: Kymera, Oliver Distler Speakers bureau: Bayer, Boehringer Ingelheim, Janssen, Medscape, Consultant of: Abbvie, Acceleron, Alcimed, Amgen, AnaMar, Arxx, AstraZeneca, Baecon, Blade, Bayer, Boehringer Ingelheim, Corbus, CSL Behring, 4P Science, Galapagos, Glenmark, Horizon, Inventiva, Kymera, Lupin, Miltenyi Biotec, Mitsubishi Tanabe, MSD, Novartis, Prometheus, Roivant, Sanofi and Topadur, Grant/research support from: Kymera, Mitsubishi Tanabe, Boehringer Ingelheim.

OP0080 STAT3 DEGRADERS INHIBIT Th17 DEVELOPMENT AND CYTOKINE PRODUCTION RESULTING IN PROFOUND INHIBITION OF COLLAGEN-INDUCED AUTOIMMUNE MURINE ARTHRITIS

Background

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that belongs to a class of targets devoid of catalytic function, thus deemed “undruggable” by standard modalities such as small molecule inhibitors or biologics. STAT3 can be activated by various receptor- and non-receptor tyrosine kinases, playing a critical role in activation pathways triggered by cytokines, hormones, and growth factors, making it an attractive target for the treatment of inflammatory diseases.

Objectives

Kymera has developed heterobifunctional molecules that selectively target STAT3 for degradation and elimination by the ubiquitin-proteasome pathway. We sought to evaluate the pharmacologic potential of these STAT3 degraders through in vitro and in vivo studies relevant to human autoimmune disease, including murine collagen-induced arthritis.

Methods

We evaluated the impact of STAT3 degraders on the activation of human monocytes, dermal fibroblasts, CD4+ T cells, and PBMC by LPS, IL-6/IL-6R, IL-21, IL-23, as well as anti-CD3/CD28 plus a cocktail of cytokines and antibodies. STAT3 degradation and pSTAT3 inhibition were determined in comparison to a JAK1/2 small molecule inhibitor. Inhibition of cytokines, chemokines, and collagen release, as well as Th17 (CD4+CD25-RORγt+CXCR6+) and Treg (CD4+CD25+CD127lowFOXP3+) expansion were used as in vitro efficacy assays. Finally, STAT3 degraders were tested in vivo, in a mechanistic (IL-6 challenge) as well as a disease model (murine CIA) relevant to rheumatology indications.

Results

STAT3 degraders showed broad and potent activity in-vitro against TLR receptor and cytokine-induced activation of immune and stromal cells, including soluble mediator release such as MCP-1/CCL2 and Collagen1a1. STAT3 degradation in CD4+ T cells robustly inhibited the development of Th17 cells, abrogating IL-17, IL-22, IL-8/CXCL8, and TNFα production, and increased Treg numbers in a manner superior to JAK1/2 inhibition. In mice injected with IL-6, plasma levels of serum amyloid A were dose-dependently suppressed by STAT3 degradation. In the murine collagen-induced arthritis model, STAT3 degradation resulted in robust, dose-dependent delay of disease onset and decreased disease incidence, clinical scores, local cytokine expression (paws) and histopathological scores, including the complete alleviation of periosteal bone growth.

Conclusion

These data demonstrate the broad activity of STAT3 degradation in alleviating autoimmune inflammation in models relevant to human disease. Targeted protein degradation of STAT3 thus represents a novel therapeutic approach to treating autoimmune/autoinflammatory diseases such as rheumatoid arthritis.

Disclosure of Interests

Cedric Hubeau Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Jeffrey Sullivan Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Crystal Brown Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Michele Mayo Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Vaishali Dixit Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Bradley Enerson Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Haojing Rong Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Bin Yang Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Chris De Savi Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Jared Gollob Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Nello Mainolfi Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics, Anthony Slavin Shareholder of: Kymera Therapeutics, Employee of: Kymera Therapeutics.

The Mammalian Spermatogenesis Single-Cell Transcriptome, from Spermatogonial Stem Cells to Spermatids

Spermatogenesis is a complex and dynamic cellular differentiation process critical to male reproduction and sustained by spermatogonial stem cells (SSCs). Although patterns of gene expression have been described for aggregates of certain spermatogenic cell types, the full continuum of gene expression patterns underlying ongoing spermatogenesis in steady state was previously unclear. Here, we catalog single-cell transcriptomes for >62,000 individual spermatogenic cells from immature (postnatal day 6) and adult male mice and adult men. This allowed us to resolve SSC and progenitor spermatogonia, elucidate the full range of gene expression changes during male meiosis and spermiogenesis, and derive unique gene expression signatures for multiple mouse and human spermatogenic cell types and/or subtypes. These transcriptome datasets provide an information-rich resource for studies of SSCs, male meiosis, testicular cancer, male infertility, or contraceptive development, as well as a gene expression roadmap to be emulated in efforts to achieve spermatogenesis in vitro.

Short range order in elemental liquids of column IV

The short range order (SRO) in liquid elements of column IV is analysed within the quasi-crystalline model across a wide range of temperatures. It is found that l-Si, Ge, and Sn are well described with a beta-tin like SRO. In contrast, Pb retains a bcc-like SRO similar to other simple elemental liquids. However, a distinction is found between the SRO in Si and Ge and that in Sn, where the latter has a more rigid structure. This difference persists across the entire temperature range examined but is overcome in Si at pressures above 8 GPa, where the liquid structure evolves towards that of Sn.

Short range order in liquid pnictides

Liquid pnictides have anomalous physical properties and complex radial distribution functions. The quasi-crystalline model of liquid structure is applied to interpret the three-dimensional structure of liquid pnictides. It is shown that all the column V elements can be characterized by a short range order lattice symmetry similar to that of the underlying solid, the A7 structure, which originates from a Peierls distorted simple cubic lattice. The evolution of the liquid structure down the column as well as its temperature and pressure dependence is interpreted by means of the effect of thermodynamic parameters on the Peierls distortion. Surprisingly, it is found that the Peierls effect increases with temperature and the nearest neighbour distances exhibit negative thermal expansion.

Continuous CSF drainage in AD: results of a double-blind, randomized, placebo-controlled study

BACKGROUND

Alzheimer disease (AD) has been associated with abnormal cerebral clearance of macromolecules, such as amyloid and microtubule-associated-protein tau (MAP-tau). We hypothesized that improving clearance of macromolecules from the CNS might slow the progression of dementia.

OBJECTIVE

This prospective, randomized, double-blinded, placebo-controlled trial evaluated the safety and effectiveness of a surgically implanted shunt in subjects with probable AD.

METHODS

A total of 215 subjects with probable AD by National Institute of Neurological Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria received either a low-flow ventriculoperitoneal shunt or a sham (occluded) shunt for 9 months. Longitudinal CSF sampling was performed in both active and control subjects. Primary outcome measures were the Mattis Dementia Rating Scale and the Global Deterioration Scale. CSF Abeta((1-42)) and MAP-tau also were assayed.

RESULTS

After a planned interim analysis, the study was halted for futility. Using the intent-to-treat population, no between-group differences were observed in the primary outcome measures. The surgical procedure and device were associated with 12 CNS infections, some temporally associated with CSF sampling. All were treated successfully.

CONCLUSIONS

We found no benefit to low-flow CSF shunting in subjects with mild to severe Alzheimer disease. CSF infections, while treatable, occurred more frequently than expected, in some cases likely related to CSF sampling.

The epidemiology of melioidosis in the Balimo region of Papua New Guinea

The distribution of Burkholderia pseudomallei was determined in soil collected from a rural district in Papua New Guinea (PNG) where melioidosis had recently been described, predominately affecting children. In 274 samples, 2.6% tested culture-positive for B. pseudomallei. Pulsed-field gel electrophoresis using SpeI digests and rapid polymorphic DNA PCR with five primers demonstrated a single clone amongst clinical isolates and isolates cultured from the environment that was commonly used by children from whom the clinical isolates were derived. We concluded that individuals in this region most probably acquired the organism through close contact with the environment at these sites. Burkholderia thailandensis, a closely related Burkholderia sp. was isolated from 5.5% of samples tested, an observation similar to that of melioidosis-endemic areas in Thailand. This is the first report of an environmental reservoir for melioidosis in PNG and confirms the Balimo district in PNG as melioidosis endemic.

Phase II trial of imatinib (I) and docetaxel (D) in recurrent non-small cell lung cancer (NSCLC)

18132

Background: Second line monotherapy for NSCLC produces a response rate of 9% and a median survival of 7–8 months, regardless of the agent used. Emerging data suggest that combining an approved agent with an anti-angiogenesis inhibitor may improve efficacy in the salvage setting. Platelet Derived Growth Factor Receptor alpha (PDGFR-alpha) is involved in angiogenesis and its expression has been reported in 100% of adenocarcinoma (11/11) and 89% of squamous cell (16/18) lung cancer specimens in a small group sample. Preclinical models have shown that I inhibits PDGFR and may subsequently inhibit angiogenesis. In addition, I + D have additive anticancer activity. We initiated a phase II trial of I +D to evaluate the efficacy and safety of this combination regimen in recurrent NSCLC. Methods: Patients (pts)with pathologically confirmed NSCLC, measurable disease, no more than 1 previous platinum-based chemotherapy regimen, PS 0–1, clinically stable brain metastases and adequate organ function were eligible. Tumor samples, when available, were tested for PDGFR expression by immunohistochemistry. All pts received D 30mg/m2 intravenously weekly x 3 every 4 weeks and oral I 600mg daily for 4 cycles. Non- progressors after 4 cycles continued with I alone for a total of 12 months or until progression. Tumor response was assessed every 2 cycles. The primary endpoint was response rate. A Simon two-stage design was used with 16 patients in the first stage and accrual of a total of 32 patients planned. Results: Currently 15/16 patients for stage I of the protocol have been enrolled. A total of 24 cycles of combined I+D were given. Patient characteristics and toxicity data are described in the table below. Efficacy data is premature. Conclusion : I +D combination has been well tolerated in this relapsed population. A detailed toxicity, efficacy and PDGFR analysis will be presented.

[Table: see text]

No significant financial relationships to disclose.

Perioperative Complications of Lung Transplantation in Patients With Emphysema and Fibrosis: Experience From 1992–2002

Our objective was to describe the incidence of perioperative complications of lung transplantation among patients with emphysema and fibrosis and the morbidity and mortality risk factors.

MATERIALS AND METHODS

We performed a retrospective study of 111 lung transplant patients engrafted from 1992 to 2002 for emphysema (n = 65) or lung fibrosis (n = 46). This descriptive study included the most frequent complications during the perioperative period in the intensive care unit.

RESULTS

The most frequent intraoperative complications were reperfusion syndrome, hemodynamic instability, and cardiac arrhythmias. Among patients with emphysema, the follow-up of postoperative complications proved statistically significant on univariate analysis for an association of patient mortality with prolonged intubation (P = .005), rejection (P = .0001), hemorrhage (P = .0001), sepsis (P = .0001), renal failure (P = .001), and implantation response (P = .014). Mortality among these patients was 16.9%. Mechanical ventilation for over 48 hours and postoperative hemorrhage were the variables with the greatest predictive value for mortality in the postoperative period. Among patients with fibrosis, the complication-related mortality were reperfusion syndrome (P = .039), implantation response (P = .039), renal failure (P = .013), rejection (P = .016), and sepsis (P < .001). The mortality rate was 23.9% with sepsis (P = .000) being the most frequent cause of death in the immediate postoperative period.

CONCLUSIONS

The most frequent intraoperative complications were reperfusion syndrome and hemodynamic instability. The most frequent postoperative complications were implantation response, sepsis, prolonged intubation, hemorrhage, and renal failure.

Preliminary immune response (IR) results of a phase 2 study with idiotype (Id) immunotherapy after treatment with CVP and rituximab for follicular non-Hodgkin’s lymphoma (FL)

7529

Background: Idiotype (Id) is a collection of unique immunogenic epitopes present on the surface of malignant B cells. Keyhole limpet hemocyanin (KLH) is a carrier protein used to increase antigen immunogenicity. MyVax Personalized Immunotherapy consists of the patient- and tumor-specific Id protein, produced using molecular techniques, conjugated to KLH and administered in a series of subcutaneous immunizations with the adjuvant GM-CSF. Idiotype vaccines were first studied in combination with various chemotherapeutic agents as part of initial treatment for FL. Given the widespread usage of rituximab in treating FL, the nature of IRs in patients immunized with MyVax Personalized Immunotherapy following rituximab treatment are of interest. CD19+ B cell counts following treatment with rituximab were analyzed for correlation with patient-specific Id-KLH induced humoral IR data. Methods: In a Phase 2 study, MyVax Personalized Immunotherapy following rituximab is being evaluated for patients who failed to achieve at least a PR and maintain the response over a 6 month rest period after 8 cycles of CVP chemotherapy. Eligible patients received 4 weekly doses of rituximab followed by a 13 or 26 week rest period. Patients who achieved and maintained a PR or better then received 8 immunizations with MyVax Personalized Immunotherapy over 14 weeks. CD19+ B cells and humoral IRs against Id and KLH were monitored during and 2, 8, 20, 32, 44 and 56 weeks post-immunizations. Results: 87 pts received rituximab. 52 pts went on to immunization. Median CD19 counts for all arms of the study were lower post-rituximab treatment (pre-treatment median = 76 cells/ul (N = 57) vs. post-treatment = 13 cells/ul (N = 51 evaluable); p < 0.0001). Positive results are defined as a titer >0.1 mcg/ml. 49/52 (94%) evaluable pts were able to mount anti-KLH humoral IRs post rituximab. The magnitude of the anti-KLH response was generally greater in pts with higher B cell counts when beginning immunizations. Anti-Id IRs were also observed. Conclusions: Humoral IRs to KLH occur in pts receiving MyVax Personalized Immunotherapy and correlate with regeneration of B cells post-rituximab but appear less robust than in rituximab-naïve pts.

[Table: see text]

Preliminary report on the northern Australian melioidosis environmental surveillance project

An environmental surveillance programme was developed to determine whether water supplies could be a source of Burkholderia pseudomallei as noted during previous melioidosis outbreak investigations. Water supplies to communities in the three northern Australian jurisdictions (Western Australia, Northern Territory and Queensland) were sampled periodically during 2001 and 2002. Water and soil samples were collected from communities known to have had recent culture-positive melioidosis cases and nearby communities where no cases had been diagnosed. Clinical isolates of B. pseudomallei obtained from northern Australian patients during 2001 and 2002 were compared with the environmental B. pseudomallei isolates by ribotyping and pulsed-field gel electrophoresis. B. pseudomallei was isolated from 11 distinct locations, all in the Northern Territory, seven of which were associated with culture-positive melioidosis cases (>1 case at three locations). Water was implicated as a possible environmental source of melioidosis in six locations. A variety of free-living amoebae including Acanthamoeba and Hartmannella spp. that are potential hosts to B. pseudomallei were recovered from environmental specimens. Culturable B. pseudomallei was not found to be widely dispersed in the environments sampled.

[Lung transplantation for pulmonary fibrosis: perioperative morbidity and mortality]

Lung transplantation has become a valid therapeutic option for patients with pulmonary fibrosis in terminal stage, and the number of such interventions has increased exponentially in recent years. We undertook a retrospective study of 46 pulmonary fibrosis patients who received lung transplants from 1992 through 2002 with the aim of describing the most common intra- and early postoperative complications in the recovery unit. We also aimed to analyze the impact of each complication on mortality during the study period. The most frequent complications during surgery were reperfusion syndrome (47.5%), hemodynamic instability (41%), arrhythmias (23.9%), and pulmonary hypertension (15%), with exitus secondary to reperfusion syndrome. The most common postoperative complications were infection (56.5%), reimplantation response (45.7%), and kidney failure (19.6%). Overall mortality during the study period was 23.9%. The following complications were statistically significant in the univariate analysis of the relation with mortality: reperfusion syndrome (p=0.039), reimplantation response (p=0.039), kidney failure (p=0.013), rejection (p=0.016), and sepsis (p<0.001). The only complication that remained significant in the multivariate analysis was sepsis (p<0.001). In spite of the considerable progress made, intra- and postoperative complications continue to be a real threat for the transplanted lung patient. Sepsis was the strongest predictor of poor prognosis in the early recovery period.

Assessment of low-flow CSF drainage as a treatment for AD: results of a randomized pilot study

OBJECTIVE

This prospective, randomized, controlled study was designed to investigate the safety, feasibility, and preliminary efficacy of long-term CSF drainage via a low-flow ventriculoperitoneal shunt in subjects suffering from AD.

METHODS

Twenty-nine subjects selected for probable AD (National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer's Disease and Related Dementias Association criteria) were screened to exclude normal pressure hydrocephalus or other etiologies of dementia and randomized to treatment (shunt) or no treatment groups. The study endpoint was the comparison of group performance on psychometric testing at quarterly intervals for 1 year. Shunted subjects had CSF withdrawn for MAP-tau and Abeta((1-42)) assays at the same time intervals.

RESULTS

There was no mortality from the surgical procedure, and no patient sustained a subdural hematoma. Five notable postoperative adverse events, which resolved without permanent neurologic deficit, were reported in the shunt group. Group mean Mattis Dementia Rating Scale total scores showed little change over the year in the shunt-treatment group, in contrast to a decline in the control group (p = 0.06). Mini-Mental State Examination mean scores supported a trend in favor of shunt treatment (p = 0.1). There was a concomitant decrease in ventricular CSF concentrations of AD biomarkers MAP-tau and Abeta((1-42)).

CONCLUSIONS

The surgical procedure and the device are reasonably safe. Adverse events were consistent with shunt procedures for hydrocephalus in this older population. The endpoint data show a trend in favor of the treated group. A larger, randomized, double-blinded, controlled, clinical trial is underway.

Yield of intestinal metaplasia in patients with suspected short-segment Barrett's esophagus (SSBE) on repeat endoscopy

Biopsies from short segments of columnar appearing mucosa in the distal esophagus often fail to reveal intestinal metaplasia (IM). The yield of IM on repeat upper endoscopy (EGD) and biopsy in these patients is not known. Our aim was to prospectively evaluate the yield of IM on repeat EGD in patients with suspected SSBE (negative for IM on first EGD). Forty-three patients with suspected SSBE underwent repeat EGD with biopsy. This included 42 men and 1 woman, mean age 53 years (range: 45-90) with a mean columnar mucosa length of 1.26 cm (range: 0.5-2.5). On repeat EGD, 10 of 43 patients (23.2%) had evidence of IM. There was no statistically significant difference between the patients with proven SSBE on repeat EGD compared to those with persistent negative IM with regards to age, ethnicity, length of columnar mucosa, GERD symptoms, and hiatal hernia size. In conclusion, more than 20% of patients with suspected SSBE have evidence of IM (ie, proven SSBE) on repeat EGD. Thus repeat EGD with biopsy may be warranted in patients with tongues of columnar mucosa in the distal esophagus but no IM on the first biopsy to confirm the diagnosis of SSBE.

A cluster of melioidosis cases from an endemic region is clonal and is linked to the water supply using molecular typing of Burkholderia pseudomallei isolates

Nine cases of melioidosis with four deaths occurred over a 28-month period in members of a small remote Aboriginal community in the top end of the Northern Territory of Australia. Typing by pulsed-field gel electrophoresis showed isolates of Burkholderia pseudomallei from six of the cases to be clonal and also identical to an isolate from the community water supply, but not to soil isolates. The clonality of the isolates found in this cluster contrasts with the marked genetic diversity of human and environmental isolates found in this region which is hyperendemic for B. pseudomallei. It is possible that the clonal bacteria persisted and were propagated in biofilm in the water supply system. While the exact mode of transmission to humans and the reasons for cessation of the outbreak remain uncertain, contamination of the unchlorinated community water supply is a likely explanation.

Burkholderia pseudomallei virulence: definition, stability and association with clonality

Clinical presentations of melioidosis, caused by Burkholderia pseudomallei are protean, but the mechanisms underlying development of the different forms of disease remain poorly understood. In murine melioidosis, the level of virulence of B. pseudomallei is important in disease pathogenesis and progression. In this study, we used B. pseudomallei-susceptible BALB/c mice to determine the virulence of a library of clinical and environmental B. pseudomallei isolates from Australia and Papua New Guinea. Among 42 non-arabinose-assimilating (ara(-)) isolates, LD(50) ranged from 10 to > 10(6) CFU. There were numerous correlations between virulence and disease presentation in patients; however, this was not a consistent observation. Virulence did not correlate with isolate origin (i.e. clinical vs environmental), since numerous ara(-) environmental isolates were highly virulent. The least virulent isolate was a soil isolate from Papua New Guinea, which was arabinose assimilating (ara(+)). Stability of B. pseudomallei virulence was investigated by in vivo passage of isolates through mice and repetitive in vitro subculture. Virulence increased following in vivo exposure in only one of eight isolates tested. In vitro subculture on ferric citrate-containing medium caused attenuation of virulence, and this correlated with changes in colony morphology. Pulsed-field gel electrophoresis and randomly amplified polymorphic DNA typing demonstrated that selected epidemiologically related isolates that had variable clinical outcomes and different in vivo virulence were clonal strains. No molecular changes were observed in isolates after in vivo or in vitro exposure despite changes in virulence. These results indicate that virulence of selected B. pseudomallei isolates is variable, being dependent on factors such as iron bioavailability. They also support the importance of other variables such as inoculum size and host risk factors in determining the clinical severity of melioidosis.

Stature estimation from radiographically determined long bone length in a Spanish population sample

The estimation of stature from of a variety of bones is an important aspect of forensic work. In order to obtain reliable results, it is important to have comparative data obtained from the same population group as the skeletal remains. However, lack of up to date information on the population groups of Southern Europe makes the estimation of stature from bones in this area subject to possible error. In this study, the stature of 104 healthy adults from Spain was measured, and an anteroposterior teleradiograph of the right lower and the right upper limb of every subject in the study was made in order to measure the lengths of the femur, tibia, fibula, humerus, cubitus and ulna. Pearson's regression formulae were obtained for both limbs. In males, we found the femur to be the most accurate predictor of stature (R = 0.851), whereas in females best results were obtained with the tibia (R = 0.876).

RAG1 and RAG2 expression by B cell subsets from human tonsil and peripheral blood

It has been suggested that B cells acquire the capacity for secondary V(D)J recombination during germinal center (GC) reactions. The nature of these B cells remains controversial. Subsets of tonsil and blood B cells and also individual B cells were examined for the expression of recombination-activating gene (RAG) mRNA. Semiquantitative analysis indicated that RAG1 mRNA was present in all tonsil B cell subsets, with the largest amount found in naive B cells. RAG2 mRNA was only found in tonsil naive B cells, centrocytes, and to a lesser extent in centroblasts. Neither RAG1 nor RAG2 mRNA was routinely found in normal peripheral blood B cells. In individual tonsil B cells, RAG1 and RAG2 mRNAs were found in 18% of naive B cells, 22% of GC founder cells, 0% of centroblasts, 13% of centrocytes, and 9% of memory B cells. Individual naive tonsil B cells containing both RAG1 and RAG2 mRNA were activated (CD69(+)). In normal peripheral blood approximately 5% of B cells expressed both RAG1 and RAG2. These cells were uniformly postswitch memory B cells as documented by the coexpression of IgG mRNA. These results indicate that coordinate RAG expression is not found in normal peripheral naive B cells but is up-regulated in naive B cells which are activated in the tonsil. With the exception of centroblasts, RAG1 and RAG2 expression can be found in all components of the GC, including postswitch memory B cells, some of which may circulate in the blood of normal subjects.

Changes in expression of the lysosomal membrane glycoprotein, LAMP-1 in interdigital regions during embryonic mouse limb development, in vivo and in vitro

Syndactyly, a failure of the digits to separate into individual units, affects about 8 to 9 per 1000 newborns and results from an aberration of the normal development of the interdigital tissues. Limb digit separation is the result of programmed cell death (apoptosis). Lysosomes play a role in the process of cell self-destruction. Our experiment was designed to test the hypothesis that the intensity of interdigital lysosomes increases during the separation of digits in vivo and in vitro. The primary mouse monoclonal antibody, 1D4B, detects the presence of lysosomes by identifying the LAMP-1 glycoprotein on the lysosome cell membrane. In our experiment this antibody immunodetected interdigital lysosome proteins in serial sections of limbs from Swiss-Webster mouse embryos, gestational ages E12.5 through E15, key developmental stages for digit separation. Digit separation was associated with an increase in intensity of lysosomal protein staining. In E12.5 limbs, the presence of lysosomes was enriched in the distal aspect of the interdigital tissue. However, the number of lysosomes markedly increased in the E13 and E14 limbs, including the entire length and width of the interdigital tissue in the E14 limbs. This lysosomal protein presence in E14 limbs was significant compared to E12.5, E13, and E15 limbs. By day 12.5, the mouse embryo limb is committed to digit separation. Addition of retinoic acid to the culture medium of limbs earlier in development, such as E12, results in induction of the process of digit separation. Cultured E12 limbs that did not receive an addition of retinoic acid, did not show digit separation. We conclude that in the limb development process, the enrichment in interdigit LAMP-1 proteins, may indicate a relationship between lysosomes, apoptosis, and digit separation. We also conclude that retinoic acid has an important role in digit separation in vivo, as shown in limb development, and demonstrated through the addition of retinoic acid to media of cultured tissues.

Ziconotide, a new N-type calcium channel blocker, administered intrathecally for acute postoperative pain

BACKGROUND AND OBJECTIVES

Voltage-sensitive calcium channel conductance is essential for the nervous system to signal a painful event. However, intrathecal administration of L-type calcium channel blockers does not provide analgesia. The present investigation was designed to assess the safety and analgesic efficacy of ziconotide, a new N-type calcium channel blocker, when administered intrathecally to patients with acute postoperative pain.

METHODS

This randomized, double-blind, pilot study included patients undergoing elective total abdominal hysterectomy, radical prostatectomy, or total hip replacement. After intrathecal injection of local anesthetic and before surgical incision, a continuous intrathecal infusion of either placebo or 1 of 2 doses of ziconotide (0.7 microg/h or 7.0 microg/h) was started and continued for 48 to 72 hours postoperatively. Primary and secondary efficacy variables were the mean daily patient controlled analgesia (PCA) morphine equivalent consumption and visual analog pain intensity (VASPI) scores, respectively.

RESULTS

Thirty patients received study drug; 26 were evaluable for efficacy. Mean daily PCA morphine equivalent consumption was less in patients receiving ziconotide than in placebo-treated patients, and the difference was statistically significant between 24 and 48 hours (P = .040). VASPI scores during the first 8 hours postoperatively were markedly lower in ziconotide-treated than in placebo-treated patients. In 4 of 6 patients receiving the high-dose of ziconotide (7 microg/h), adverse events, such as dizziness, blurred vision, nystagmus, and sedation contributed to study drug being discontinued after 24 hours. After ziconotide discontinuation, these symptoms resolved.

CONCLUSIONS

Ziconotide showed analgesic activity, as shown by decreased PCA morphine equivalent consumption and lower VASPI scores. Because of a favorable trend of decreased morphine consumption with an acceptable side-effect profile in the low-dose ziconotide group, 0.7 microg/h may be closer to the ideal dose than 7 microg/h. Large-scale studies are required to clarify this issue.

Removal of UroLume endoprosthesis: experience of the North American Study Group for detrusor-sphincter dyssynergia application

PURPOSE

We present the experience of the North American UroLume Multicenter Study Group with removal of the UroLume endoprosthesis.

MATERIALS AND METHODS

A total of 160 neurologically impaired patients were enrolled in the North American UroLume Multicenter Study Group for detrusor external sphincter dyssynergia application. Analysis was performed in 2 groups of patients in which the device was removed during insertion and after implantation, respectively.

RESULTS

Device retrieval was required during insertion in 21 patients (13%) mainly due to misplacement or migration in 17. Extraction was done with minimal complications and in all but 2 cases subsequent UroLume implantation was successful. Of 158 men with the device in place 31 (19.6%) required removal. In 34 procedures 44 devices were removed, mainly due to migration. Time from implantation to removal ranged from 4 days to 66 months (mean 22 months). The UroLume was removed en bloc in 20 cases and in parts or wire by wire in 19. The majority of patients had no or minimal complications after extraction. Only 2 patients had serious temporary complications, including bleeding and urethral injury, with no lasting consequences. No malignancy developed as a result of UroLume insertion.

CONCLUSIONS

While there is a potential for urethral injury and bleeding, UroLume endoprosthesis removal is largely a simple procedure with minimal complications and consequences.

Expression of functional recombinant antibody molecules in insect cell expression systems

Recombinant single-chain variable-fragment molecules (scFv) were constructed from a cell line expressing a monoclonal antibody against African cassava mosaic virus (ACMV) and expressed in Escherichia coli. DNA sequences that encoded the scFv were manipulated to allow scFv expression in insect cell lines. A recombinant baculovirus containing the scFv cDNA was constructed and large amounts of scFv were produced in each of three insect cell lines infected with the baculovirus. However, the scFv were not secreted into the medium by any of the cell lines despite the scFv having been linked to a honeybee melittin leader sequence. The same scFv cDNA construct was introduced into Drosophila DS2 cells and a stable recombinant cell line was obtained that produced scFv that was secreted into the medium. Culture medium containing the scFv was used directly in enzyme-linked immunosorbent assay (ELISA) tests to detect ACMV in plant tissues. Another construct that encoded the Ckappa domain of human IgG was fused to the C-terminus of the scFv that was produced and expressed in Drosophila cells. This scFv derivative also accumulated in the medium and was more active in ELISA than scFv lacking the Ckappa domain.

Animal melioidosis in Australia

Melioidosis was first diagnosed in Australia in sheep in 1949. While it has been considered endemic in tropical Australia, there have been animal outbreaks in southwest Western Australia and southern Queensland. Infection occurs in many species, with both latency and a wide range of clinical manifestations. Some species may develop melioidosis only if immunocompromised. Sheep and goats are particularly susceptible, resulting in the requirement for pasteurisation of tropical commercial goat's milk. Nine out of 43 (21%) goats had aortic lesions at autopsy and seven died from aortic aneurysm rupture. Transplacental transmission in goats has also been documented. Asymptomatic organ abscesses are common in pigs but bovine melioidosis is very rare. Camels moved north and an alpaca brought to Darwin have died from melioidosis. It also occurs in wildlife, including birds, crocodiles and kangaroos. Zoonotic transmission to humans is extremely unusual, but there are many similar epidemiological and clinical features of melioidosis in animals and humans. There have been three possible zoonotic cases in Australia. Molecular typing has found identical Burkholderia pseudomallei organisms from animals, humans and soil. The study of melioidosis in animals, especially the use of molecular genetic techniques for organism identification and typing, will continue to unravel aspects of the disease that remain unclear in humans.

Expression of myogenic regulatory factors during the development of mouse tongue striated muscle

While the role of myogenic regulatory factors (MRFs) in skeletal myogenesis has been well evaluated in limb and trunk muscles, very little is known about their role in tongue myogenesis. Here the expression of MRF mRNA in mouse tongue muscle was examined during development from embryonic day (E)11 to birth and compared them with that in hind-limb muscle. Desmin, muscle creatine kinase and troponin C mRNAs were used as markers for myoblast determination, myotubule formation and myofibre maturation, respectively. The mRNA quantities were determined by competitive reverse transcriptase-polymerase chain reaction. The expression profile of desmin mRNA indicated that myoblast determination occurred before E11 in both the tongue and hind-limb muscles; the profile of muscle creatine kinase and troponin C mRNAs indicated that myotubule formation and myofibre maturation began between E11 and 13 in both tongue and hind-limb muscles, but ended 2 days earlier in the tongue than in the hind limb. Expression of myoD and myogenin mRNAs began at E11, increased, and showed peak values earlier in the tongue muscle (E13) than in the hind-limb muscle (E15). Expression of MRF4 mRNA appeared earlier in the tongue (E13) than in the hind-limb muscle (E15) and increased in both muscles after that. These results suggest that myotubule formation and myofibre maturation in the tongue muscle progress faster than in the hind-limb muscle, a result of earlier expression of myoD, myogenin, and MRF4 in response to earlier functional demands such as suckling immediately after birth.

Acute melioidosis outbreak in Western Australia

A cluster of acute melioidosis cases occurred in a remote, coastal community in tropical Western Australia. Molecular typing of Burkholderia pseudomallei isolates from culture-confirmed cases and suspected environmental sources by pulsed-field gel electrophoresis (PFGE) of XbaI chromosomal DNA digests showed that a single PFGE type was responsible for five cases of acute infection in a community of around 300 during a 5 week period. This temporal and geographical clustering of acute melioidosis cases provided a unique opportunity to investigate the environmental factors contributing to this disease. B. pseudomallei isolated from a domestic tap at the home of an asymptomatic seroconverter was indistinguishable by PFGE. Possible contributing environmental factors included an unusually acid communal water supply, unrecordable chlorine levels during the probable exposure period, a nearby earth tremor, and gusting winds during the installation of new water and electricity supplies. The possible role of the potable water supply as a source of B. pseudomallei was investigated further.

Phase II study of interferon-enhanced 131I-labeled high affinity CC49 monoclonal antibody therapy in patients with metastatic prostate cancer

Adjuvant Interferon (IFN) was given to increase tumor antigen expression and enhance localization with 131I-labeled CC49 radioimmunotherapy in a Phase II trial for hormone resistant metastatic prostate cancer. Patients received four doses of alpha-IFN (3 x 10(6) IU) s.c. on alternate days, from day -5 to day +1 of 75 mCi/m2 131I-CC49 treatment. Toxicity was well tolerated, with the majority of patients experiencing transient grade 3 or 4 neutropenia and/or thrombocytopenia (maximal at 4-6 weeks). The absorbed dose was >25 Gy in four of eight tumors visualized, which represents an increase of >20 fold over whole body radiation dose. Two patients had radiographic minor responses by 6 weeks post-therapy, whereas five of six patients experiencing pain had symptom relief without radiographic changes. The protocol provided modest antitumor effects (pain relief in five of six patients and two minor radiographic responses). This study suggests that the addition of IFN enhanced tumor uptake and antitumor effects as compared to a prior Phase II trial of 131I-CC49 alone.

The cytoadherence linked asexual gene family of Plasmodium falciparum: are there roles other than cytoadherence?

The binding of erythrocytes infected with Plasmodium falciparum to the endothelium lining the small blood vessels of the brain and other organs can mediate severe pathology. A region at the right end of chromosome 9 has been implicated in the binding of parasitised erythrocytes to the endothelial receptor CD36. A gene expressed in asexual erythrocytic stage parasites has been identified in this region and termed the cytoadherence linked asexual gene (clag). Antisense RNA production and targeted gene disruption of clag resulted in greatly reduced binding to CD36. Hybridisation to 3D7 chromosomes showed clag to be a part of a gene family of at least nine members. All members analysed so far have a conserved gene structure of at least nine exons, as well as putative transmembrane domains. The possible functions of the gene family are discussed.

Long-term followup of the North American multicenter UroLume trial for the treatment of external detrusor-sphincter dyssynergia

PURPOSE

We determine the long-term efficacy and safety of the UroLume stent as minimally invasive treatment for external detrusor-sphincter dyssynergia in spinal cord injured men.

MATERIALS AND METHODS

A total of 160 spinal cord injured men with a mean age plus or minus standard deviation of 36.3 +/- 12.1 years (range 16 to 74) were prospectively treated with an endoprosthesis at 15 centers as part of the North American UroLume trial for external detrusor-sphincter dyssynergia. Urodynamic parameters, including voiding pressure, residual urine volume and bladder capacity, were compared before treatment and at 1, 2, 3, 4 and 5 years after treatment.

RESULTS

Mean voiding pressure was 75.1 +/- 28.2 cm. water before treatment in the 160 patients, and 37.4 +/- 23.9 at year 1 in 97, 39.5 +/- 22.2 at year 2 in 84, 42.6 +/- 27.3 at year 3 in 61, 46.3 +/- 33.2 at year 4 in 57 and 44.2 +/- 28.9 cm. at year 5 in 41 after stent insertion (p <0.001). Residual urine volume decreased after stent placement and was maintained throughout the 5-year followup (p <0.001). Mean cystometric capacity remained constant from 269 +/- 155 before insertion to 337 +/- 182 ml. 5 years later (p = 0.17). Hydronephrosis and autonomic dysreflexia improved or stabilized in most patients with functioning stents. Stent explant was necessary in 24 patients (15%), of whom 4 (16.7%) had another stent implanted.

CONCLUSIONS

The UroLume stent demonstrates long-term safety and efficacy for the treatment of external detrusor-sphincter dyssynergia. The outcome was similar in men with and without previous sphincterotomy.

Murine tongue muscle displays a distinct developmental profile of MRF and contractile gene expression

Few studies have addressed the molecular differences that exist between muscles of the body and those of the craniofacial apparatus. In this study, we characterize the molecular events associated with determination and differentiation of the tongue musculature. We assess the expression of myogenic regulatory factors as well as the developmentally regulated myosin heavy chain, (MHC), genes which serve as markers of differentiation. These results suggest that tongue and limb muscle form by distinct molecular pathways. The myoblasts that contribute to the formation of the tongue preferentially express Myf-5 during myoblast determination rather than MyoD. Subsequently, isolated regions of myogenin expression mark the differentiation of first, the small primary myofibers and later, the larger secondary myofibers. Analysis of differentiation markers demonstrates that the tongue muscle also assumes a unique profile of MHC expression as compared to that of the muscles of the body. Unlike the myoblasts of the developing limb, which express embryonic and neonatal forms of MHC and later express MHC-slow, the tongue myoblasts co-express MHC-embryonic, MHC-slow and MHC-fast isoforms from gestational age E12. Proteins for MHC embryonic and MHC fast isoforms are detected almost simultaneously. Interestingly, MHC-slow transcripts do not appear to be translated into a detectable MHC slow protein at any developmental stage assayed. These results provide further evidence to suggest that skeletal tongue muscle represents a myoblast lineage that develops differently than the limb.