Abstract 6063: Genomic characterization of non-small cell lung cancer (NSCLC) brain metastasis (BM) patients identifies novel alterations associated with tropisms and disease progression

Intro: Half of all patients with NSCLC develop BM during their clinical course. While modern NSCLC-directed agents yield excellent systemic response, most patients require focal BM treatment. Prior reports of BM genomics have been limited by low numbers and a lack of matched specimens. Here, we report the largest cohort to date of molecularly-profiled NSCLC BM samples with comprehensive clinical follow-up.

Methods: Clinical data and outcomes for 244 patients with NSCLC and resected BM were identified. Samples were assessed using MSK-IMPACT, a custom tumor-normal next generation sequencing assay. 51 (20.9%) patients had matched primary site tissue, and 44 (18%) patients had matched tissue from another metastatic site or CSF. Genomic alterations were filtered for driver variants using OncoKB. Publicly available genomic data for NSCLC primary samples was used for comparison against the primary samples from our BM cohort.

Results: The most frequently altered genes in BM tumors were TP53 (72%), CDKN2A (34%), KRAS (31%), KEAP1 (26%), and EGFR (21%). CDKN2A was more frequently altered in BM samples compared to NSCLC primary lesions (34% vs 14%, p = 0.003). Additionally, cell cycle pathway alterations were enriched in BM (56% vs 31%, p = 0.002). BM samples also had a significantly higher fraction of genome altered (FGA) relative to primary samples (p < 0.0001). We then compared primary samples from BM patients against primary samples from metastatic NSCLC patients without BM and primary samples from non-metastatic NSCLC patients. We found an enrichment of alterations in TP53 (68.6% vs 27.7%, p < 0.0001), NKX2-1 (11.4% vs 1.7%, p = 0.006), SMARCA4 (11.4% vs 2.1%, p = 0.01), RB1 (11.4% vs 1.7%, p = 0.006), and FOXA1 (11.4% vs 0.9%, p = 0.001) in the primary samples from BM patients compared to non-metastatic patients. Next, we grouped patients based on CNS progression patterns and found that EGFR alterations were enriched in patients with leptomeningeal progression when compared to patients without progression (42% vs 18%, p = 0.03).

Conclusions: In our cohort of molecularly-profiled NSCLC BM, we found an enrichment of cell cycle pathway alterations and a higher FGA in BMs compared to their primary tumor controls. Additionally, several genes were enriched in the primary tissue of patients that developed BM compared to primary tissue from non-metastatic patients. EGFR alterations were enriched in patients who develop leptomeningeal disease (LMD). Our work herein characterizes the genomic profiles of NSCLC patients with BM and identifies specific genes enriched in the primary tissue of BM patients compared to primary tissue from both non-BM metastatic patients and non-metastatic patients. Finally, our finding that EGFR alterations were enriched in patients with LMD suggests specific biologic underpinnings driving patterns of CNS progression.

Citation Format: Henry Walch, Anna Skakodub, Kathryn R. Tringale, Harish N. Vasudevan, Jordan Eichholz, Daniel W. Kelly, Emily Lebow, Nelson S. Moss, Kenny Kwok Hei Yu, Bob T. Li, Boris Mueller, Atif Khan, Yao Yu, Simon Powell, Jorge S. Reis-Filho, Brandon S. Imber, Pedram Razavi, Daniel R. Gomez, Nikolaus Schultz, Luke R. Pike. Genomic characterization of non-small cell lung cancer (NSCLC) brain metastasis (BM) patients identifies novel alterations associated with tropisms and disease progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6063.

Characterization of Central Nervous System Clinico-Genomic Outcomes in ALK-Positive Non-Small Cell Lung Cancer Patients with Brain Metastases Treated with Alectinib

INTRODUCTION

Highly effective brain-penetrant ALK-targeted tyrosine kinase inhibitors (TKIs) have been developed for the management of NSCLC patients with brain metastases (BM). Local therapy (LT) such as SRS or therapeutic craniotomy is increasingly being deferred for such patients. Herein we report detailed patient- and lesion-level intracranial outcomes and co-mutational genomic profiles from a cohort of NSCLC patients with BM treated with alectinib, with or without LT.

METHODS

We retrospectively reviewed ALK fusion-positive NSCLC patients with BMs who received alectinib at the diagnosis of BM from 1/2012 and 5/2021. Outcome variables included intracranial progression-free survival (iPFS), overall survival (OS), duration of TKI therapy, and CNS response rates. Genomic characteristics from tumor specimens were assessed with MSK-IMPACT, a next-generation sequencing (NGS)-based genomic profiling assay.

RESULTS

A total of 38 patients with 114 CNS lesions were included. Twelve of these patients also received contemporaneous LT (SRS, WBRT, or surgical resection). Maximal BM diameter in the TKI + LT group was greater (p < 0.003) but despite this difference, iPFS (TKI only, HR 1.21, 95 % CI 0.51-2.89; p = 0.66) and OS (TKI only, HR 5.99, 95 % CI 0.77-46.6; p = 0.052) were similar between groups and trended towards more favorable outcomes with the addition of LT. SMARCA4 co-alterations were associated with inferior OS (HR 8.76, 1.74-44.2; p = 0.009).

CONCLUSIONS

Our study demonstrated that patients with ALK fusion-positive NSCLC treated with TKI + LT had larger BM and higher likelihood of pre-treatment neurologic symptoms. Despite these differences, iPFS was similar between groups. Results should be interpreted with caution as our study was limited by an underpowered sample size. SMARCA4 co-alterations were associated with inferior OS and these findings warrant further investigation.

Molecular profile and clinical outcomes of renal cell carcinoma brain metastases treated with stereotactic radiosurgery

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Background: Molecular profiles of renal cell carcinoma (RCC) tumors are associated with systemic treatment (ST) responses and clinical outcomes. However, the molecular profiles of RCC brain metastases (BM) and their correlation with ST response and clinical outcomes are not well characterized. Effective management of BM with locoregional therapies including stereotactic radiosurgery (SRS) is critical as ST advances have improved overall survival (OS). Therefore, we sought to identify the clinical and genomic features of RCC BM in a large cohort of patients treated with SRS. Methods: We performed an institutional retrospective analysis of RCC BM patients treated with SRS and evaluated corresponding genomic next generation sequencing (NGS) data via a targeted sequencing panel (MSK-IMPACT). A comparison cohort of all institutional patients with available NGS data was utilized to investigate genes enriched in our BM cohort using Fisher exact testing. Kaplan Meier analyses were performed for OS and intracranial progression-free survival (iPFS). Clinical factors and genes mutated in ≥ 10% of samples were assessed per patient using Cox proportional hazards models, and per individual BMs using clustered competing risks regression with a competing risk of death. Results: From 2010-2021, 91 RCC BM patients underwent SRS for 212 BMs, including 86% clear cell and 14% non-clear cell RCC. NGS data was available for 76 patients (84%), including 18 resected BMs, 26 extra-cranial metastatic lesions (EM), and 32 primary kidney tumors (Table 1). Median follow-up was 3.2 years with median OS of 21 months (m) and median iPFS of 7.8m. Karnofsky performance status ≥80 and extracranial disease control were significantly associated with improved OS on multivariable analyses (MVA; p=0.049 and 0.01, respectively). No clinical variables were significantly associated with iPFS on MVA. At the BM level, SETD2 alterations approached significance for improved iPFS (HR=0.35; 95%CI 0.11, 1.05; p=0.06). Enrichment in SMARCA4 alterations was seen in the BM cohort as compared to primary kidney and EM samples from patients without BM (17% vs 1% vs 2%, p<0.05). Conclusions: To our knowledge, this is the largest study investigating mutational profiles of RCC BM. SMARCA4 alterations were enriched in BM samples and a trend towards improved iPFS was seen in SETD2 variant BMs, warranting further investigation.[Table: see text]

Genomic analysis and clinical correlations of non-small cell lung cancer (NSCLC) brain metastasis (BM)

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Background: Approximately 30% of patients with NSCLC present with BM, and up to 50% of patients ultimately develop BM. While modern NSCLC-directed agents yield excellent systemic response, most patients require focal treatment. Prior reports of BM genomics have been limited by low numbers, missing clinical data, and lack of matched specimens. Here, we report the largest cohort to date of molecularly profiled NSCLC BM samples with clinical correlates. Methods: Clinical data and outcomes for 244 patients with NSCLC and resected BM were identified, and BM samples were assessed with one of four versions (341, 410, 468, 505) of MSK-IMPACT, a custom FDA-approved next generation sequencing-based tumor sequencing assay. 51 (20.9%) patients had matched primary site tissue, and 44 (18%) patients had matched tissue from another metastatic site or CSF. Genomic alterations were filtered for driver variants using OncoKB. Results: Median age was 66 years (range 31-91), and median follow-up was 2.3 years (IQR 1.3-4.3). Adenocarcinoma was the most common histology (183, 78%). Half presented with a single BM, and 121 (51%) patients were treatment naive. Most (197, 83%) received adjuvant stereotactic radiosurgery (SRS) to the resection site and 28% received SRS to additional BM. After resection, 130 (55.1%) had CNS progression, often regional (54, 42%). SRS to new BMs (32%) was the most common salvage treatment. Median overall survival from BM diagnosis was 2.5 years (95%CI 2.1-3.2). Median CNS-progression-free survival was 1.2 years (95%CI 0.9-1.4). The most frequently altered genes in BM samples were TP53 (72%), CDKN2A (34%), KRAS (31%), KEAP1 (26%), and EGFR (21%). CDKN2A was more frequently altered in BM samples when compared to NSCLC primary samples (34% vs 14%, p = 0.003, q = 0.034). With regard to overrepresented gene sets, cell cycle pathway alterations were enriched in BM (56% vs 31%, p = 0.002, q = 0.022). BM samples had a significantly higher fraction of genome altered relative to the primary samples (p < 0.0001, q < 0.0001). After grouping patients based on type of CNS progression, we found that EGFR alterations were enriched in patients with leptomeningeal failures when compared to both patients without progression (42% vs 18%, p = 0.03, q = 0.93) and to patients with either local or regional progression (42% vs 19%, p = 0.03, q = 0.9). Conclusions: In the largest-ever assembled cohort of genomically-profiled NSCLC BM, we found significant enrichment for CDKN2A and cell cycle pathway alterations in BM compared to extracranial disease, as well as a higher fraction of genome altered, in BMs compared to matched primary tumor controls. We also observed EGFR alteration enrichment in patients who develop LMD, suggesting specific biologic underpinnings driving patterns of CNS failure. Further investigation into the role of systemic therapy and time course will elucidate potential mechanisms for CNS failure in patients with NSCLC.

Impact of Exercise on Susceptibility and Severity of COVID-19 in Patients with Cancer: A Retrospective Study

BACKGROUND

Modifiable lifestyle-related factors heighten the risk and severity of coronavirus disease 2019 (COVID-19) in patients with cancer. Whether exercise lowers susceptibility or severity is not known.

METHODS

We identified 944 cancer patients from Memorial Sloan Kettering Cancer Center (mean age: 64; 85% female; 78% White) completing an exercise survey before receiving a confirmed positive or negative SARS-CoV-2 test. Exercise was defined as reporting moderate-intensity ≥5 days per week, ≥30 minutes/session or strenuous-intensity ≥3 days per week, ≥20 minutes/session. Multivariable logistic regression was used to determine the relationship between exercise and COVID-19 susceptibility and severity (i.e., composite of hospital admission or death events) with adjustment for clinical-epidemiologic covariates.

RESULTS

Twenty-four percent (230/944) of the overall cohort were diagnosed with COVID-19 and 35% (333/944) were exercisers. During a median follow-up of 10 months, 26% (156/611) of nonexercising patients were diagnosed with COVID-19 compared with 22% (74/333) of exercising patients. The adjusted OR for risk of COVID-19 was 0.65 [95% confidence interval (CI), 0.44-0.96, P = 0.03] for exercisers compared with nonexercisers. A total of 20% (47/230) of COVID-19 positive patients were hospitalized or died. No difference in the risk of severe COVID-19 as a function of exercise status was observed (P > 0.9).

CONCLUSIONS

Exercise may reduce the risk of COVID-19 infection in patients with a history of cancer, but not its severity.

IMPACT

This study provides the first data showing that exercise might lower the risk of COVID-19 in cancer patients, but further research is required.

The association between tumor mutational burden and prognosis is dependent on treatment context

In multiple cancer types, high tumor mutational burden (TMB) is associated with longer survival after treatment with immune checkpoint inhibitors (ICIs). The association of TMB with survival outside of the immunotherapy context is poorly understood. We analyzed 10,233 patients (80% non-ICI-treated, 20% ICI-treated) with 17 cancer types before/without ICI treatment or after ICI treatment. In non-ICI-treated patients, higher TMB (higher percentile within cancer type) was not associated with better prognosis; in fact, in many cancer types, higher TMB was associated with poorer survival, in contrast to ICI-treated patients in whom higher TMB was associated with longer survival.

Effects of radiation therapy on clonal hematopoiesis

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Background: Clonal hematopoiesis (CH), characterized by recurrent somatic mutations in blood, is a common age-associated condition that portends an increased risk of myeloid neoplasms and cardiac disease. Oncologic therapies appear to promote CH, including ionizing radiation therapy (RT) (OR = 1.4, p < 10−6) and systemic DNA-damaging agents (OR = 1.2, p = 8x10−4). How various RT parameters (e.g. target site, dose, fractionation, modality) may influence CH is unknown. Methods: CH mutations were identified via targeted, deep-coverage next-generation sequencing from paired peripheral blood and tumor samples (MSK-IMPACT). CH was defined as a somatic blood mutation with a minimum variant allele frequency of 2%. Putative driver mutations (CH-PD) were identified from OncoKB and other published sources. Clinical and RT characteristics were abstracted from medical records. To account for differences in RT dose and fractionation, equivalent radiation dose in 2 Gy fractions (EQD2) with an α/β ratio of 3 for late effects was calculated. Univariate and logistic regression modeling for associations between clinical and treatment parameters and CH were performed. Results: We identified 2,195 patients who received RT before blood draw and 7,832 who did not, encompassing 57 histologies. A median of 267 days elapsed between the end of RT and blood draw. After RT, 22% of patients had at least one CH-PD mutation (n = 486). The most common single anatomic sites radiated were pelvis, chest wall/breast, and head and neck. Conventional RT was used in 2% (n = 46), 3D-conformal in 14% (n = 308), intensity modulated RT in 36% (n = 787), volumetric modulated arc RT in 12% (n = 263), multiple techniques in 26% (n = 560), and unknown in 11% (n = 231). There was no association between RT modality and presence of CH-PD (p > 0.05 for all between group comparisons of modality). On multivariate regression after controlling for age, race, time from diagnosis to blood draw, smoking status, and for chemotherapy class, cytotoxic, immune, or targeted therapies in the entire cohort, EQD2 was associated with CH-PD (p = 0.012x10−3). Evaluating EQD2 by irradiated anatomic site, total pelvic dose by EQD2 in 10 Gy increments remained significantly associated with CH-PD (OR = 1.07, p = 0.0046), as was head and neck EQD2 (OR = 1.046, p = 0.032). Conclusions: CH-PD was associated with higher radiation dose for pelvic or head and neck RT, but not other anatomic sites after controlling for systemic therapies. RT modality was not associated with CH-PD. Ongoing work will directly evaluate the bone marrow dosimetry of various treatment approaches using phantom-based modeling.

Clinical characterization of pancreatic ductal adenocarcinomas (PDAC) with mismatch repair (MMR) gene mutations

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Background: Tumors with mismatch repair-deficiency (MMRD) have a high mutational burden and have good responses to immunotherapy (Le, NEJM, 2015). We describe the natural course, clinicopathological, and genomic status of MMRD PDAC patients (pts) at Memorial Sloan Kettering Cancer Center (MSKCC). Methods: MSKCC institutional registry and ICD billing database queried from 2006-2016 for PDAC pts with genetically confirmed mutations in mismatch repair (MMR) genes. Mutation # determined via MSK-IMPACT, a targeted tumor next generation sequencing (NGS) test (Cheng, J Mol Diagn, 2015). Results: 5/607 (0.8%) PDAC pts had Lynch syndrome (LS) (confirmed germline mutations) (Table 1). Of the 5 LS pts, all had > 10 mutations in NGS, with 4 of 5 having > 50 mutations. 4 of 5 (80%) are alive at last follow-up (survival 30-314 months). N=4 had extensive personal/family history of cancer. Of N=3 who had resected disease, all 3 had recurrence at 11, 49 and 311 months, and all are alive (survival: 69-314 months). Of N= 2 pts that had unresectable tumors, one passed away at 30 months while the other is on checkpoint inhibitor trial and is alive at 30 months. In contrast, 7/607 (1.1%) PDAC pts had somatic mutations in MMR genes with an average of 5.7 mutations in NGS, with 4/7 having <5 mutations. 4/7 (57%) are deceased at last follow-up (survival: 10-42 months). Conclusions: All cases with germline mutations in the MMR genes, with one exception, had high mutation #. All cases with somatic mutations in the MMR genes had low mutation #. Germline mutations in MMR genes and high mutational burden may predict for a prognostically favorable subgroup of PDAC pts with high susceptibility to immune oncology agents. [Table: see text]

Gemcitabine-Related Pneumonitis in Pancreas Adenocarcinoma--An Infrequent Event: Elucidation of Risk Factors and Management Implications

BACKGROUND

Gemcitabine-related pneumonitis (GRP) has been reported relatively frequently for pancreas cancer in the literature; however, underlying risk factors and optimal management remain to be defined. We studied a cohort of patients with GRP and investigated potential predisposing factors in pancreatic cancer patients.

PATIENTS AND METHODS

A total 2440 patients at Memorial Sloan Kettering Cancer Center were identified between January 1, 2000, and December 31, 2012, and were screened for grade 2 or higher GRP in an institutional tumor registry and using an ICD billing code database. Demographic and clinical information was extracted by electronic chart review.

RESULTS

A total of 28 patients (1.1%) with GRP were identified. Incidence of grade 2, 3, and 4 reactions were 7 (25%), 18 (64%), and 3 (11%), respectively. No GRP-related mortality was observed. Twenty-one patients (75%) reported a history of cigarette smoking. Seventeen patients (61%) were alcohol users. Six patients (21%) were either regular or heavy drinkers. Most patients (93%) had either locally advanced or metastatic disease. Three patients (11%) underwent a diagnostic bronchoscopy, and in 1 patient a diagnosis of organizing pneumonia was established. Morbidity was significant; 3 patients (11%) required treatment in the intensive care unit. All hospitalized patients received steroid treatment.

CONCLUSION

GRP is relatively uncommon but incurs significant morbidity. Potential risk factors include advanced-stage disease, along with smoking and alcohol consumption and possibly underlying lung disease. We recommend a high level of clinical alertness regarding the diagnosis, early pulmonary referral, and cessation of gemcitabine on suspicion of GRP.

Factors influencing infection patterns of trophically transmitted parasites among a fish community: host diet, host-parasite compatibility or both?

Parasite infection patterns were compared with the occurrence of their intermediate hosts in the diet of nine sympatric fish species in a New Zealand lake. Stomach contents and infection levels of three gastrointestinal helminth species were examined from the entire fish community. The results highlighted some links between fish host diet and the flow of trophically transmitted helminths. Stomach contents indicated that all but one fish species were exposed to these helminths through their diet. Host feeding behaviour best explained infection patterns of the trematode Coitocaecum parvum among the fish community. Infection levels of the nematode Hedruris spinigera and the acanthocephalan Acanthocephalus galaxii, however, were not correlated with host diets. Host specificity is thus likely to modulate parasite infection patterns. The data indicate that host diet and host-parasite compatibility both contribute to the distribution of helminths in the fish community. Furthermore, the relative influence of encounter (trophic interactions between prey and predator hosts) and compatibility (host suitability) filters on infection levels appeared to vary between host-parasite species associations. Therefore, understanding parasite infection patterns and their potential impacts on fish communities requires determining the relative roles of encounter and compatibility filters within and across all potential host-parasite associations.

Distribution of putative male sex pheromones among Lutzomyia sandflies (Diptera: Psychodidae)

Male Lutzomyia longipalpis produce terpene sex pheromones in glandular tissue underlying the cuticle. The pheromones are transmitted to the surface via cuticle-lined ducts (measuring 0.25 microm in diameter), each of which reaches the surface in the centre of a papule (measuring 3-3.5 microm in diameter). Similar papules, in a range of shapes but all characterized by the presence of a central pore and absence of macroserae, occur in some other species of sandfly. The aim of the present study was to determine the distribution of sex pheromones in sandflies of the genus Lutzomyia that do and do not have the papules. The results indicate that sex pheromones are not widely distributed amongst male Lutzomyia spp. Male members of the genus can be subdivided into three groups: those that produce terpenes and have cuticular papules; those that do not produce terpenes but still have the associated papules; and those that have neither terpenes nor papules. The papules seen in the species that do not synthesise sex pheromones are presumably vestigial, non-functional structures. Such species may have stopped producing pheromone as the result of changes in the way in which the females found and selected mates or changing feeding preferences. A similar event has occurred in the Lepidoptera, where vestigial pheromone-secreting structures remain in some species which no longer produce pheromone. Lutzomyia lenti collected in southern Brazil produced a novel diterpene whereas male L. lenti from north-eastern Brazil did not, supporting suggestions by others that L. lenti is, like L. longipalpis, a species complex.

Why are some people bitten more than others?

Much progress has been made in describing how it is, in a mechanistic sense, that some vertebrate hosts (species or individuals) are bitten more than others, principally because of their odour or appearance. Little attention has been paid to why, in an evolutionary sense, these particular animals are bitten. Irrespective of the proximate mechanisms of host choice, there must be an intense selection pressure on insects to feed on those hosts that are most amenable to being bitten. We should be better able to predict host choice by understanding the evolutionary processes at work.

Coccidiosis in the European badger (Meles meles) from England, an epidemiological study

In total 445 faecal samples were collected from 259 European badgers (Meles meles) in Wytham Woods, Oxfordshire, UK (462080). Microscopical examination revealed infection with 2 species of coccidia Eimeria melis and Isospora melis. From the initial examination of each animal, point prevalence rates of 0.44 and 0.35 were calculated for Eimeria and Isospora respectively. The intensity of infection was significantly greater for Eimeria than Isopora and the distribution of intensities was highly skewed for both species, with a few individuals shedding the majority of oocysts. Incidence and recovery rates for both coccidia species were calculated from longitudinal data collected at 3-monthly intervals from a subset of the adult badger population, and the predicted prevalence rates based on these were similar to the point prevalence rates. This suggests little, if any, parasite-induced mortality in the adult population. In contrast, there was a marked and significant reduction in the point prevalence and intensity of infection with Eimeria from cub to adult badger suggesting a degree of acquired immunity to Eimeria melis on initial exposure and/or that there is significant Eimeria-associated mortality in the cub population. No such relationship was found for Isospora infection. In those adult badgers with co-infections there was a direct relationship between the intensity of Eimeria and Isospora. The taxonomic status of these parasites suggests a heteroxenous life-cycle for I. melis, and direct transmission of E. melis. However, the greater than expected prevalence of co-infection is consistent with a common source of infection, such as communal latrines.

Epidemiology and optimal foraging: modelling the ideal free distribution of insect vectors

Existing models of the basic case reproduction number (R0) for vector-borne diseases assume (i) that the distribution of vectors over the susceptible host species is homogeneous and (ii) that the biting preference for the susceptible host species rather than other potential hosts is a constant. Empirical evidence contradicts both assumptions, with important consequences for disease transmission. In this paper we develop an Ideal Free Distribution (IFD) model of host choice by blood-sucking insects, predicated on the argument that vectors must have evolved to choose the least defensive hosts in order to maximize their feeding success. From a re-analysis of existing data, we demonstrate that the interference constant, m, of the IFD can vary between host species. As a result, the predicted distribution of insects over hosts has 2 desirable and intuitively plausible behaviours: that it is heterogeneous both within and between host species; and that the intensity of heterogeneity varies with host and vector density. When the IFD model is incorporated into R0, the relationship with the vector:host ratio becomes non-linear. If correct, the IFD could add considerable realism to models which seek to predict the effect of these ecological parameters on disease transmission as they vary naturally (e.g. through seasonality in vector density or host population movement) or as a consequence of artificial manipulation (e.g. zooprophylaxis, vector control). It raises the possibility of targeting transmission hot spots with greater accuracy and concomitant reduction in control effort. The robustness of the model to simplifying assumptions is discussed.

Differential application of lambda-cyhalothrin to control the sandfly Lutzomyia longipalpis

To study the impact of residual pyrethroid insecticide on the abundance and distribution of peridomestic Lutzomyia longipalpis, the sandfly vector of visceral leishmaniasis in Brazil, lambda-cyhalothrin was applied at 20 mg a.i.m-2 in the following interventions: (i) spraying of all animal pens in a village (blanket coverage); (ii) treatment of a subset of animal pens, either by spraying, or by installation of insecticide-impregnated 1 m2 cotton sheets as 'targets' (focal coverage). By sampling with CDC light traps, and using a novel analytical approach, we detected a 90% reduction in Lu.longipalpis abundance in sprayed sheds of the focal intervention. However, there was no discernible effect on the abundance of other phlebotomines trapped in sheds, or on the abundance of Lu.longipalpis in untreated dining-huts and houses. This differential impact on Lu.longipalpis abundance is explained in terms of the disruption of male pheromone production. Treated targets were approximately half as effective as residual spraying in reducing the abundance of Lu.longipalpis in sheds. Following blanket intervention, the abundance of Lu.longipalpis in traps fell by only 45% (not significant): catches at untreated dining-huts actually increased, possibly because the blanket coverage diverted Lu.longipalpis away from major aggregation sites at animal pens. It is recommended that care be taken during vector control programmes to ensure that all potential aggregation sites are treated. The possible consequences of leaving some sites untreated include poor control of peridomestic sandfly abundance and an increase in the biting rate on dogs and humans.

A model of spine, ribcage and pelvic responses to a specific lumbar manipulative force in relaxed subjects

One class of manipulative techniques commonly used during assessment and treatment of spinal disorders involves the patient lying face down while the therapist slowly applies a posteroanterior force to a selected vertebra. The aim of this investigation was to develop a model which was capable of predicting the vertebral displacements resulting from such a manipulative force, applied to the lumbar spine. A linear three-dimensional finite element model was generated using both previously published and original data to define the geometry and material properties. The complete model included the ribcage, thoraco-lumbar spine and pelvis with their associated soft tissues. The model simulated the relaxed state in a normal subject so the muscle forces were assumed to be negligible. Sensitivity analysis suggested that if the model was to be used to simulate the behaviour of individual subjects, then the model dimensions and pelvic constraints should be matched to the particular subject. The model validity was studied by comparing the predicted responses with those that have been observed in living human subjects. The model predictions were found to be in good agreement with the mean observed human responses, with predicted displacements being within one standard deviation of the mean observed values. This agreement suggests that the model is useful for predicting the linear region responses to slowly applied lumbar posteroanterior forces. The simulations predicted that appreciable global vertebral displacements (up to 1.5 mm) and rotations (up to 1 degree) occurred as far away as the middle and lower thoracic spine during low lumbar loading. Intervertebral translations were predicted to be 1 mm or more at up to four intervertebral joints away from the point of load application.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolism of methapyrilene by Fischer-344 rat and B6C3F1 mouse hepatocytes

1. Suspension cultures of freshly isolated F344 rat and B6C3F1 mouse hepatocytes were compared for their ability to transform various concentrations of methapyrilene (MP). 2. MP metabolites were isolated and purified by h.p.l.c., and were identified by comparing their chromatographic and mass spectral properties with those of authentic standards. 3. Both rat and mouse hepatocytes transformed MP to tentatively identified 2-thiophenecarboxylic acid (I), and definitively identified mono-N-desmethyl methapyrilene glucuronide (II), methapyrilene glucuronide (III), methapyrilene N-oxide (V), and mono-N-desmethyl methapyrilene (VII).

Regulation of prostaglandin E2 production by vitamin D metabolites in growth zone and resting zone chondrocyte cultures is dependent on cell maturation

The production of PGE2 by chondrocytes and its regulation by vitamin D metabolites was examined in this study as a function of cell maturation. Costochondral chondrocytes, derived from the resting zone and growth zone cartilage, were grown in culture to fourth passage. At confluence, they were exposed to 10(-8)-10(-11)M 1,25-(OH)2D3 or to 10(-7)-10(-10)M 24,25-(OH)2D3 for either five minutes or 3, 6, 12, or 24 hours. Indomethacin (10(-7)M) was added to one-half of the cultures to block the production of PGE2. The amount of PGE2 released into the media was determined by radioimmunoassay. Both growth zone and resting zone cells produced PGE2 in a time-dependent manner; PGE2 concentration was greater in the resting zone cell cultures. 1,25-(OH)2D3 stimulated PGE2 production by growth zone cells in a dose-dependent manner, significant at 10(-8)-10(-10)M. This effect was observed at 3 hours and remained elevated during the 24 hours of culture. 1,25-(OH)2D3 had no effect on PGE2 production by resting zone cells. However, 24,25-(OH)2D3 (10(-7)-10(-8)M) inhibited PGE2 production from 3-24 hours. No effect was noted when 24,25-(OH)2D3 was added to growth zone cells. Indomethacin reduced PGE2 production to baseline values in all groups examined. The results indicate that chondrocytes in culture produce PGE2. Production is regulated by vitamin D3 metabolites and is cell maturation-dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma elimination and urinary excretion of methapyrilene in the rat

The metabolism and elimination of methapyrilene (2-[(2-dimethylaminoethyl)-2-thenylamino]pyridine) were characterized after the iv administration of 0.7 mg/kg or 3.5 mg/kg methapyrilene HCl plus [14C]methapyrilene HCl to adult male Fischer-344 rats. Approximately 40% and 35% of the administered dose was excreted in the urine in the first 24 hr in the low and high dose groups, respectively, as determined by liquid scintillation spectrophotometry. Fecal excretion accounted for 38% and 44% of the administered dose in the first 24 hr in the low and high dose groups, respectively, as confirmed via combustion analysis. The 24-hr urinary metabolic products consisted of one major and five minor radiolabeled compounds. The major metabolite was isolated with reversed-phase HPLC and identified as methapyrilene N-oxide. This was accomplished by comparison of the chromatographic and mass spectral characteristics of this metabolite with that of authentic methapyrilene N-oxide. Methapyrilene and mono-N-desmethyl methapyrilene also were identified after isolation with reversed-phase HPLC and comparison of their mass spectral and/or chromatographic properties with those of authentic compounds. The plasma metabolic profile was essentially the same as the urinary profile. The elimination of methapyrilene from plasma occurred through a first-order process. The terminal plasma elimination t1/2 of methapyrilene did not increase with increasing doses (2.75 hr, 0.7 mg/kg; 2.81 hr, 3.5 mg/kg); thus, methapyrilene does not exhibit dose-dependent elimination over this 5-fold dose range.

The metabolism and elimination of pyrilamine maleate in the rat

The metabolism and elimination of pyrilamine (2-[(2-dimethylamino-ethyl)(p-methoxybenzyl)amino]pyridine) were characterized after the iv administration of 7.0 mg/kg or 0.7 mg/kg pyrilamine maleate plus [14C]pyrilamine maleate to adult male Fischer-344 rats. Approximately 29% and 38% of the administered dose was excreted in the urine in the first 24 hr in the high and low dose groups, respectively, as determined by liquid scintillation spectrometry. Fecal excretion accounted for 27% and 30% of the administered dose in the first 24 hr in the high and low dose groups, respectively, as confirmed via combustion analysis. The 24-hr urinary metabolic products consisted of one major and four minor radiolabeled compounds. The major metabolite was isolated by reversed-phase high performance liquid chromatography and identified as the O-glucuronic acid conjugate of O-demethyl pyrilamine. This was accomplished by comparison of the chromatographic characteristics of this metabolite's aglycon with that of an authentic standard of O-demethyl pyrilamine and fast atom bombardment mass spectrometry of the unhydrolyzed conjugate. Pyrilamine and its N-oxide and O-demethyl derivatives were also identified after isolation by reversed-phase high performance liquid chromatography and comparison of their mass spectral and/or chromatographic properties with those of authentic compounds. The plasma metabolic profile was essentially the same as the urinary profile except for the absence of O-demethyl pyrilamine. The plasma elimination of pyrilamine fit a one-compartment open model and was first order. The terminal plasma elimination half-life of pyrilamine did not increase with increasing doses (2.3 hr, 0.7 mg/kg; 1.5 hr, 7.0 mg/kg) and thus pyrilamine does not exhibit dose-dependent elimination.(ABSTRACT TRUNCATED AT 250 WORDS)

Microbial metabolism of pyrene

The isolation and identification of pyrene metabolites formed from pyrene by the fungus Cunninghamella elegans is described. C. elegans was incubated with pyrene for 24 h. Six metabolites were isolated by reversed-phase high-performance liquid (HPLC) and thin-layer chromatography (TLC) and characterized by the application of UV absorption, 1H-NMR and mass spectral techniques. C. elegans hydroxylated pyrene predominantly at the 1,6- and 1,8-positions with subsequent glucosylation to form glucoside conjugates of 1-hydroxypyrene, 1,6- and 1,8-dihydroxypyrene. In addition, 1,6- and 1,8-pyrenequinones and 1-hydroxypyrene were identified as metabolites. Experiments with [4-14C]pyrene indicated that over a 24-h period, 41% of pyrene was metabolized to ethyl acetate-soluble metabolites. The glucoside conjugates of 1-hydroxypyrene, 1,6- and 1,8-dihydroxypyrene accounted for 26%, 7% and 14% of the pyrene metabolized, respectively. Pyrenequinones accounted for 22%. The results indicate that the fungus C. elegans metabolized pyrene to non-toxic metabolites (glucoside conjugates) as well as to compounds (pyrenequinones) which have been suggested to be biologically active in higher organisms. In addition, there was no metabolism at the K-region of the molecule which is a major site of enzymatic attack in mammalian systems.

Patellar and quadriceps tendon ruptures--jumper's knee

We reviewed 13 patients with end stage jumper's knee, 10 with patellar tendon ruptures, and 3 with ruptures of the quadriceps tendon to evaluate our long-term results in treating these tendon ruptures in an athletic population. The focus was on the natural history, the time until return, and the level of return, to athletic activity. Jumper's knee affected all patients to a varying degree prior to rupture. Basketball was the most common sport involved. At followup, averaging 4 1/2 years, patients underwent functional and clinical, as well as Cybex and roentgenographic, evaluations. Results indicated patellar tendon ruptures, where the ruptures are complete, have a more favorable prognosis than those of the quadriceps tendon which are incomplete. All of the latter patients continued to have quadriceps tendinitis following repair. In both groups, the poor results were obtained in patients with chondromalacia and/or patella alta. Cybex testing yielded results of greater than 100% strength in three patients with patellar tendon ruptures, but no patient with quadriceps rupture had comparable test results. There was no apparent relationship between ruptures and cortisone injections. Patellar and quadriceps tendon ruptures from indirect injury in athletes represent the end stage of jumper's knee and result from repetitive microtrauma. Excellent function usually follows repair of patellar tendon ruptures when surgery is performed early and care is taken to restore normal patellar tendon length. Results of quadriceps ruptures are less satisfactory since these ruptures are usually incomplete and all degenerative tissue may not be involved in the healing response.

Congenital dislocation of the radial head: spectrum and natural history

A retrospective review of 24 patients with congenital radial head dislocation and three patients with congenital elbow dysplasias was performed. Eight patients had only congenital radial head dislocations and no other anomalies. In these eight patients, a noted limitation of elbow and forearm motion was greatest in those with anterior dislocations. Limitation of wrist motion also was noted in all affected extremities. Unilateral congenital radial head dislocation as well as progressive subluxation to dislocation were documented. There was no increased loss of motion as growth occurred. Significant pain was noted only in adults. Radial head excision after age 15 relieved pain and improved cosmesis but failed to significantly affect motion. Excision performed prior to this age showed regrowth of the proximal radius. A finding of increased ulnar length in relation to the radius in wrist roentgenograms of affected extremities was a significant diagnostic sign.

Quadriceps rupture in association with the roentgenographic "tooth" sign: a case report

This article reports a case of quadriceps tendon rupture in association with the roentgenographic "tooth" sign. This sign has not been reported previously in association with quadriceps tendon rupture, but may be helpful in assisting in the early diagnosis of this injury.