Just in case: undergraduate students identifying and mitigating barriers to their sexual and reproductive health needs

BACKGROUND

Many U.S. colleges and universities offer access to a healthcare center that provides sexual and reproductive health (SRH) resources, services, and products. The importance of health centers in college and university settings in reducing sexual health disparities in student populations cannot be stressed enough. This article evaluates a student-led, mutual-aid, grassroots health promotion strategy for students with limited access to healthcare services, supplies, and tools via an anonymous and discrete distribution of SRH resources without charge.

METHODS

In partnership with faculty, undergraduate students worked to address their school's unmet SRH needs by increasing on-campus access to comprehensive, evidence-based, and sex-positive resources. Referred to as Just in Case, this student-led, grassroots health promotion program provided students with supply kits containing contraceptives, sexual health wellness products, basic hygiene supplies, and education materials. Students were surveyed in a pre- (n = 95) post- (n = 73) pilot study to identify contraception acquisition barriers, discern perceptions of on-campus SRH resources, and elucidate trends in this program's use and impact. Chi-square tests of independence were used to compare survey group responses, and association rule mining was employed in tandem to identify SRH items that students requested.

RESULTS

Students identified cost and privacy as significant barriers to acquiring sexual health products on campus. Of the 182 Just in Case supply kits requested by students during the 2022-2023 academic year, condoms were requested most frequently in 75% of fulfilled kits, while emergency contraception and pregnancy tests were asked most often in 61% of kits. 50% of students reported access to contraceptives on campus before this program's implementation, growing to 75% (p < 0.001) 1 year later post-implementation. Similar jumps were observed for reported access to sexual health education (30 to 73%, p < 0.001) and services (36 to 73%, p < 0.001).

CONCLUSION

A student-led SRH supply and resource delivery strategy may immediately reduce SRH inequities and decrease barriers to contraceptive use for students with limited access to on-site SRH product availability.

Abstract 1018: Time to secondary treatment initiation affects overall survival in early-stage lung cancer

Rationale: Lung cancer is the leading cause of cancer-related deaths in the US and worldwide. The 5-year overall survival (OS) for lung cancer patients is below 20%, lower than most other common cancers. In general, timely care can positively affect the survival of patients. However, previous studies of lung cancer and the effect of time-to-treatment on patient outcomes have been inconclusive. Some studies report adverse effects, while others report the association referred to as the ‘waiting time paradox’, where patients with severe diagnosis receive quicker care, but have poorer outcomes due to advanced disease. These studies investigate time-to-treatment of any type, but association between time-to-treatment for secondary treatments and outcomes for lung cancer has not been conclusively defined.

Methods: Treatment data from 714 patients with lung cancer diagnosis at Vanderbilt University Medical Center between 2001 and 2021 was used for this analysis. Secondary treatment data included data in three categories: chemotherapy (N=577), radiation therapy (N=126), and target therapies(N=11). Cox regression and Kaplan-Meir curves were used to model the effect of time-to-treatment on overall survival, adjusted for demographic and clinical factors, including if surgical resection was performed before secondary treatment start date. Time-to-treatment was defined as the interval of days between diagnosis or initial surgical procedure and treatment start date in four categories: 0-10 days (1), 11-20 days (2), 21-30 days (3), 31-45 days (4).

Results: Cox proportion regression analysis of patients treated within 30 days, including stage and time-to-treatment, had a significant difference in overall survival when stratified by cox linear predictor median (value = 0.0912). Patients with linear predictors values above the median (high) in the cox proportion model had a lower 3-year survival than patients with linear predictor values lower than the median (low) (p=0.0021). This contrast is seen clearly in early-stage lung cancer patients, who received chemotherapy as secondary treatment, where patients with longer time-to-treatment start (15-30 days) had a lower 3-year survival than patients with shorter time-to-treatment (0-15 days) (p=0.047).

Conclusions: The effect of changes in time-to-treatment initiation in lung cancer patients receiving secondary treatment appears to be sensitive to initiation within a 30-day period. Although past studies have focused on treatment start time initiation categories within weeks or months, our study is the first to elucidate a possible sensitivity to secondary initiation within just a few days period. Further examination aims to further detail treatment types, by investigating changes in dosage, treatment combinations, or institutions differences to better understand time-to-treatment effects on the survival rates of lung cancer patients.

Citation Format: Dianna J. Rowe, Michael Kammer, Jonathan Lehman, Fabien Maldonado. Time to secondary treatment initiation affects overall survival in early-stage lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1018.

Prediction of adenocarcinoma among other subtypes of lung cancer from CT using deep learning

3057

Background: Determination of histological subtype is a crucial step in the management of patients with lung cancer as it informs prognosis and management. The identification of adenocarcinoma (AC) is particularly important with new targeted treatments becoming available. Although the gold standard for diagnosing histological subtype is pathological analysis of tissue samples, interventions can present a risk of complication. Imaging-based, computational approaches to distinguishing malignant from benign lesions have shown promising results. A similar approach may also be applied to determining histological subtype, which could provide an early, non-invasive alternative or complimentary method to biopsy. Here, we investigate an imaging and machine learning method to predict the subtype of a malignant lung lesion. Methods: A dataset of 1493 primary lung cancer patients was collected, of which 943 were diagnosed with AC. The histological subtypes of the non-AC patients were, squamous-cell carcinoma (158), large-cell carcinoma (69), small-cell carcinoma (33), other subtypes (27), or unreported non-AC subtype (253). This consists of retrospectively collected CT images and demographic data from both screening and clinical settings, across 41 academic and community centres from the USA (35 centres), and Europe (6 centres). All patients included were aged ≥ 18 with no history of cancer in the last 5 years. Each CT was manually curated. Given a CT-image of a lung nodule, a Convolutional Neural Network (CNN) was trained to classify nodules as AC or non-AC, using 8-fold cross-validation. A logistic-regression model based on clinical parameters was also trained using the same data and cross-validation. Classification performance was evaluated using the Area-Under-the-ROC-Curve (AUC), sensitivity, and specificity. Confidence intervals and P values were calculated by nonparametric bootstrapping. Results: The median age of AC patients was 66 yr (non-AC 67 yr) and 62.3% of them were male (non-AC 57.8%). The median pack years for AC patients was 38.4 p.yr (non-AC 50.0 p.yr). For AC tumours, the median diameter was 14.0 mm (non-AC 14.0 mm) and the mean diameter was 15.0 mm (non-AC 16.4 mm). The AC-classification results are tabulated below. The CNN classification performance is significantly better than the logistic-regression baseline across all three measures of performance P <.001. AC classification results. All values are given in % with 95% confidence interval bounds in parentheses. Conclusions: We find that the CNN significantly outperforms a logistic model in identifying AC from other histological subtypes. With further development, this algorithm could prove a useful tool to aid management of lung cancer patients.[Table: see text]

New Approaches to SCLC Therapy: From the Laboratory to the Clinic

The outcomes of patients with SCLC have not yet been substantially impacted by the revolution in precision oncology, primarily owing to a paucity of genetic alterations in actionable driver oncogenes. Nevertheless, systemic therapies that include immunotherapy are beginning to show promise in the clinic. Although, these results are encouraging, many patients do not respond to, or rapidly recur after, current regimens, necessitating alternative or complementary therapeutic strategies. In this review, we discuss ongoing investigations into the pathobiology of this recalcitrant cancer and the therapeutic vulnerabilities that are exposed by the disease state. Included within this discussion, is a snapshot of the current biomarker and clinical trial landscapes for SCLC. Finally, we identify key knowledge gaps that should be addressed to advance the field in pursuit of reduced SCLC mortality. This review largely summarizes work presented at the Third Biennial International Association for the Study of Lung Cancer SCLC Meeting.

Expanding Access to Lung Cancer Clinical Trials by Reducing the Use of Restrictive Exclusion Criteria: Perspectives of a Multistakeholder Working Group

Low rates of adult patient participation have been a persistent problem in cancer clinical trials and have continued to be a barrier to efficient drug development. The routine use of significant exclusion criteria has contributed to this problem by limiting participation in studies and creating significant clinical differences between the study cohorts and the real-world cancer patient populations. These routine exclusions also unnecessarily restrict opportunities for many patients to access potentially promising new therapies during clinical development. Multiple efforts are underway to broaden eligibility criteria, allowing more patients to enroll in studies and generating more robust data regarding the effect of novel therapies in the population at large. Focusing specifically on lung cancer as an example, a multistakeholder working group empaneled by the LUNGevity Foundation identified 14 restrictive and potentially outdated exclusion criteria that appear frequently in lung cancer clinical trials. As a part of the project, the group evaluated data from multiple recent lung cancer studies to ascertain the extent to which these 14 criteria appeared in study protocols and played a role in excluding patients (screen failures). The present report describes the working group's efforts to limit the use of these routine exclusions and presents clinical justifications for reducing the use of 14 criteria as routine exclusions in lung cancer studies, potentially expanding trial eligibility and improving the generalizability of the results from lung cancer trials.

In-Plane Vibration of Hammerhead Resonators for Chemical Sensing Applications

Thermally excited and piezoresistively detected in-plane cantilever resonators have been previously demonstrated for gas- and liquid-phase chemical and biosensing applications. In this work, the hammerhead resonator geometry, consisting of a cantilever beam supporting a wider semicircular "head", vibrating in an in-plane vibration mode, is shown to be particularly effective for gas-phase sensing with estimated limits of detection in the sub-ppm range for volatile organic compounds. This paper discusses the hammerhead resonator design and the particular advantages of the hammerhead geometry, while also presenting mechanical characterization, optical characterization, and chemical sensing results. These data highlight the distinct advantages of the hammerhead geometry over other cantilever designs.

Ph1/2 study of Rova-T in combination with nivolumab (Nivo) ± ipilimumab (Ipi) for patients (pts) with 2L+ extensive-stage (ED) SCLC

8516

Background: Rovalpituzumab tesirine (Rova-T™) is an antibody-drug conjugate targeting DLL3, a Notch ligand expressed in SCLC but not normal tissue. Nivo ± Ipi has activity in 2L+ SCLC. Preliminary data suggest Rova-T may result in immunogenic cell death, complementing effects of Nivo ± Ipi. Methods: Eligibility: DLL3 expression (DLT phase only), progression after ≥1 line of therapy including a platinum-based regimen; ECOG 0-1; no prior immunotherapy. All pts received 0.3 mg/kg Rova-T IV on Day 1 of two 6-wk cycles. Cohort 1 (C1) also received two 3-wk cycles of 360 mg Nivo beginning on wk 4. Cohort 2 (C2) received four 3-wk cycles of 1 mg/kg Nivo and 1 mg/kg Ipi beginning on wk 4. Both cohorts then received 480 mg Nivo q4wks until PD. Primary objective: safety. Secondary: antitumor activity by RECISTv1.1, OS. Exploratory: PK. Results: As of Sep 7, 2018, 30 pts were dosed in C1 and 12 in C2. 55% were DLL3 high (≥75% DLL3 expression). 28 (67%) completed 2 planned cycles of Rova-T. 4 pts (1 in C1, 3 in C2) experienced DLTs including rash (3), pneumonitis (1) and colitis (1). C1 completed recruitment, and C2 enrollment was stopped after DLT evaluation phase. Preliminary PK showed Nivo±Ipi had no substantial effect on Rova-T exposure. Clinical trial information: NCT03026166. Conclusions: Despite activity in 2L+ ED-SCLC, Rova-T with Nivo/Ipi is not appropriate due to DLTs. Rova-T/Nivo demonstrated some durable responses; however, the safety data suggest that optimization of dose and schedule is warranted. NCT03026166.[Table: see text]

68Ga-DOTATATE PET/CT imaging of indeterminate pulmonary nodules and lung cancer

PURPOSE

18F-FDG PET/CT is widely used to evaluate indeterminate pulmonary nodules (IPNs). False positive results occur, especially from active granulomatous nodules. A PET-based imaging agent with superior specificity to 18F-FDG for IPNs, is badly needed, especially in areas of endemic granulomatous nodules. Somatostatin receptors (SSTR) are expressed in many malignant cells including small cell and non-small cell lung cancers (NSCLCs). 68Ga-DOTATATE, a positron emitter labeled somatostatin analog, combined with PET/CT imaging, may improve the diagnosis of IPNs over 18F-FDG by reducing false positives. Our study purpose was to test this hypothesis in our region with high endemic granulomatous IPNs.

METHODS

We prospectively performed 68Ga-DOTATATE PET/CT and 18F-FDG PET/CT scans in the same 30 patients with newly diagnosed, treatment-naïve lung cancer (N = 14) or IPNs (N = 15) and one metastatic nodule. 68Ga-DOTATATE SUVmax levels at or above 1.5 were considered likely malignant. We analyzed the scan results, correlating with ultimate diagnosis via biopsy or 2-year chest CT follow-up. We also correlated 68Ga-DOTATATE uptake with immunohistochemical (IHC) staining for SSTR subtype 2A (SSTR2A) in pathological specimens.

RESULTS

We analyzed 31 lesions in 30 individuals, with 14 (45%) being non-neuroendocrine lung cancers and 1 (3%) being metastatic disease. McNemar's result comparing the two radiopharmaceuticals (p = 0.65) indicates that their accuracy of diagnosis in this indication are equivalent. 68Ga-DOTATATE was more specific (94% compared to 81%) and less sensitive 73% compared to 93%) than 18F-FDG. 68Ga-DOTATATE uptake correlated with SSTR2A expression in tumor stroma determined by immunohistochemical (IHC) staining in 5 of 9 (55%) NSCLCs.

CONCLUSION

68Ga-DOTATATE and 18F-FDG PET/CT had equivalent accuracy in the diagnosis of non-neuroendocrine lung cancer and 68Ga-DOTATATE was more specific than 18F-FDG for the diagnosis of IPNs. IHC staining for SSTR2A receptor expression correlated with tumor stroma but not tumor cells.

Atomic clock with 1×10(-18) room-temperature blackbody Stark uncertainty

The Stark shift due to blackbody radiation (BBR) is the key factor limiting the performance of many atomic frequency standards, with the BBR environment inside the clock apparatus being difficult to characterize at a high level of precision. Here we demonstrate an in-vacuum radiation shield that furnishes a uniform, well-characterized BBR environment for the atoms in an ytterbium optical lattice clock. Operated at room temperature, this shield enables specification of the BBR environment to a corresponding fractional clock uncertainty contribution of 5.5×10(-19). Combined with uncertainty in the atomic response, the total uncertainty of the BBR Stark shift is now 1×10(-18). Further operation of the shield at elevated temperatures enables a direct measure of the BBR shift temperature dependence and demonstrates consistency between our evaluated BBR environment and the expected atomic response.

Evaluating the thermal damage resistance of graphene/carbon nanotube hybrid composite coatings

We study laser irradiation behavior of multiwalled carbon nanotubes (MWCNT) and chemically modified graphene (rGO)-composite spray coatings for use as a thermal absorber material for high-power laser calorimeters. Spray coatings on aluminum test coupon were exposed to increasing laser irradiance for extended exposure times to quantify their damage threshold and optical absorbance. The coatings, prepared at varying mass % of MWCNTs in rGO, demonstrated significantly higher damage threshold values at 2.5 kW laser power at 10.6 μm wavelength than carbon paint or MWCNTs alone. Electron microscopy and Raman spectroscopy of irradiated specimens show that the coating prepared at 50% CNT loading endure at least 2 kW x cm(-2) for 10 seconds without significant damage. The improved damage resistance is attributed to the unique structure of the composite in which the MWCNTs act as an efficient absorber of laser light while the much larger rGO sheets surrounding them, dissipate the heat over a wider area.

Very high laser-damage threshold of polymer-derived Si(B)CN-carbon nanotube composite coatings

We study the laser irradiance behavior and resulting structural evolution of polymer-derived silicon-boron-carbonitride (Si(B)CN) functionalized multiwall carbon nanotube (MWCNT) composite spray coatings on copper substrate. We report a damage threshold value of 15 kWcm(-2) and an optical absorbance of 0.97 after irradiation. This is an order of magnitude improvement over MWCNT (1.4 kWcm(-2), 0.76), SWCNT (0.8 kWcm(-2), 0.65) and carbon paint (0.1 kWcm(-2), 0.87) coatings previously tested at 10.6 μm (2.5 kW CO2 laser) exposure. Electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy suggests partial oxidation of Si(B)CN forming a stable protective SiO2 phase upon irradiation.

Synthesis of polymer-derived ceramic Si(B)CN-carbon nanotube composite by microwave-induced interfacial polarization

We demonstrate synthesis of a polymer-derived ceramic (PDC)-multiwall carbon nanotube (MWCNT) composite using microwave irradiation at 2.45 GHz. The process takes about 10 min of microwave irradiation for the polymer-to-ceramic conversion. The successful conversion of polymer coated carbon nanotubes to ceramic composite is chemically ascertained by Fourier transform-infrared and X-ray photoelectron spectroscopy and physically by thermogravimetric analysis and transmission electron microscopy characterization. Frequency dependent dielectric measurements in the S-Band (300 MHz to 3 GHz) were studied to quantify the extent of microwave-CNT interaction and the degree of selective heating available at the MWCNT-polymer interface. Experimentally obtained return loss of the incident microwaves in the specimen explains the reason for heat generation. The temperature-dependent permittivity of polar molecules further strengthens the argument of internal heat generation.

Directional cell migration and chemotaxis in wound healing response to PDGF-AA are coordinated by the primary cilium in fibroblasts

Cell motility and migration play pivotal roles in numerous physiological and pathophysiological processes including development and tissue repair. Cell migration is regulated through external stimuli such as platelet-derived growth factor-AA (PDGF-AA), a key regulator in directional cell migration during embryonic development and a chemoattractant during postnatal migratory responses including wound healing. We previously showed that PDGFRalpha signaling is coordinated by the primary cilium in quiescent cells. However, little is known about the function of the primary cilium in cell migration. Here we used micropipette analysis to show that a normal chemosensory response to PDGF-AA in fibroblasts requires the primary cilium. In vitro and in vivo wound healing assays revealed that in ORPK mouse (IFT88(Tg737Rpw)) fibroblasts, where ciliary assembly is defective, chemotaxis towards PDGF-AA is absent, leading to unregulated high speed and uncontrolled directional cell displacement during wound closure, with subsequent defects in wound healing. These data suggest that in coordination with cytoskeletal reorganization, the fibroblast primary cilium functions via ciliary PDGFRalpha signaling to monitor directional movement during wound healing.

Role for CD44 in Enhancing Invasion, Migration, and Growth of Triple Negative (TN) Breast Cancer Cells

Triple negative (TN) breast cancers are defined by a lack of expression of estrogen, progesterone, and her-2/neu receptors. It is widely recognized that TN breast cancers have a poorer prognosis than any other subtypes of breast caner. Given the lack of effective targeted therapies for TN breast cancer patients, understanding of the mechanisms of growth and invasion in the tissues provides insight into developing novel approaches to lower the mortality from TN breast cancer.Neoplastic epithelial cells in breast carcinomas interact with various components in the tissue microenvironment including extracellular matrix (ECM) and mesenchymal cells. Recent studies identified CD44 as a metastasis-related molecule with multiple functions by promoting cell-cell and cell-ECM interactions. CD44 is an integral transmembrane protein encoded by a single 20-exon gene. In the standard form (CD44s), 10 of the 20 exons are translated. Multiple variant isoforms exist (CD44v1-10) which arises from alternate mRNA splicing of the remaining 10 exons. In contrast to the ubiquitous expression of the standard form of CD44, splice variants are highly restricted in their expression in normal or malignant tissues. Indeed, CD44 variants containing v3, v5, v6, v7-8, v10 exons are expressed in malignant breast cancer tissues. However, there is limited information regarding the biological functions of these exons to promote tumor invasion and metastasis. The goal of this study is to evaluate specific exon(s) of CD44 expressed on TN breast cancer cells for promoting tumor progression and metastasis.In order to approach this goal, we utilized three TN cell lines (HCC38, HCC1937, and HCC1806) as model systems to evaluate CD44 in regulating invasion, migration, and growth in extracellular matrix (ECM) environments. Reverse transcriptase (RT)-PCR analysis using exon specific primers indicate that these cells expressed CD44v8-v10 and CD44s. We demonstrated that an inhibitory antibody against exon v10 of CD44 significantly inhibited b1 integrin-mediated migration and invasion into Matrigel and type I collagen gel. Importantly, this antibody also inhibited three dimensional (3D) growth which is a b1 integrin-independent process. The significant inhibition of these processes was also achieved when a FLAG-fusion exon v10 peptide (FLAG-v10, in which FLAG is tagged at the N-terminal of the peptide) was used as an inhibitor, implying that this exon would function to assemble molecular complexes on TN breast cancer cells that facilitate invasion, migration, and growth. Thus, these results suggest that generation of small synthetic molecules that block the functions of exon v10 of CD44 is promising approaches to inhibit invasion and metastasis of TN breast cancer cells.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6161.

Infrared responsivity of a pyroelectric detector with a single-wall carbon nanotube coating

The performance of a 10 mm diameter pyroelectric detector coated with a single-wall carbon nanotube (SWCNT) was evaluated in the 0.8 to 20 microm wavelength range. The relative spectral responsivity of this detector exhibits significant fluctuations over the wavelength range examined. This is consistent with independent absorbance measurements, which show that SWCNTs exhibit selective absorption bands in the visible and near-infrared. The performance of the detector in terms of noise equivalent power and detectivity in wavelength regions of high coating absorptivity was comparable with gold-black-coated pyroelectric detectors based on 50 microm thick LiTaO(3) crystals. The response of this detector was shown to be nonlinear for DC equivalent photocurrents >10(-9) A, and its spatial uniformity of response was comparable with other pyroelectric detectors utilizing gold-black coatings. The nonuniform spectral responsivity exhibited by the SWCNT-coated detector is expected to severely restrict the use of SWCNTs as black coatings for thermal detectors. However, the deposition of SWCNT coatings on a pyroelectric crystal followed by the study of the prominence of the spectral features in the relative spectral responsivity of the resultant pyroelectric detectors is shown to provide an effective method for quantifying the impurity content in SWCNT samples.

Evaluation of a pyroelectric detector with a carbon multiwalled nanotube black coating in the infrared

The performance of a pyroelectric detector with a carbon multiwalled nanotube coating was evaluated in the 0.9-14 microm wavelength range. The relative spectral responsivity of this detector was shown to be flat over most of the wavelength range examined, and the spectral flatness was shown to be comparable to the best infrared black coatings currently available. This finding is promising because black coatings with spectrally flat absorbance profiles are usually associated with the highest absorbance values. The performance of the detector (in terms of noise equivalent power and specific detectivity) was limited by the very thick (250 microm thick) LiNbO3 pyroelectric crystal onto which the coating was deposited. The responsivity of this detector was shown to be linear in the 0.06-2.8 mW radiant power range, and its spatial uniformity was comparable to that of other pyroelectric detectors that use different types of black coating. The carbon nanotube coatings were reported to be much more durable than other infrared black coatings, such as metal blacks, that are commonly used to coat thermal detectors in the infrared. This, in combination with their excellent spectral flatness, suggests that carbon nanotube coatings appear extremely promising for thermal detection applications in the infrared.

Penetrance and expressivity of genes involved in the development of epilepsy in the genetically epilepsy-prone rat (GEPR)

In order to understand the level of complexity of the epileptic phenotype in the two strains of Genetically Epilepsy-Prone Rats (GEPRs), we determined two important measures of genetic complexity, penetrance and expressivity. Penetrance is the percentage of animals of a specific genotype who express the phenotype associated with that underlying genotype. Expressivity refers to the degree that a particular genotype is expressed as a phenotype within an individual. Incomplete penetrance and variable expressivity are caused by genetic and environmental variation. In this paper we have studied the epileptic phenotype for 20,373 rats. Animals were tested on three occasions for audiogenic seizure and given an audiogenic response score (on a scale of 0-9, 0 being no seizure and 9 being the most severe). The GEPR-3 and GEPR-9 animals both show incomplete penetrance and variable expressivity of the underlying genetic predisposition. The GEPR-9 strain has more animals that have variable levels of seizure predisposition (as measured by a scoring system that denotes the severity of generalized tonic/clonic seizures) and a greater percentage of animals that exhibit no susceptibility to such seizures induced by sound. Both strains have a number of animals that are not susceptible to sound-induced GTCSs and that exhibit some variability in seizure severity. The GEPR-9 males show greater differences in expressivity and penetrance compared to GEPR-9 females. The GEPR-3 animals also show sex-associated variable penetrance and expressivity of the epileptic phenotype, although the differences are much smaller. These findings are the first step toward the mapping of the underlying quantitative trait loci (QTL) for seizure in these animals.

Characterisation of atovaquone resistance in Leishmania infantum promastigotes

Atovaquone, an antiparasitic agent, could possibly represent an alternative therapy after relapse following classical treatment for visceral leishmaniasis. Atovaquone-resistant strains were selected in vitro by stepwise drug pressure to study the mechanism of resistance in Leishmania. Characteristics of a promastigote strain resistant to 250 microg/ml of atovaquone were compared with those of the wild type (WT) strain. Resistant strains were shown to have a high level of resistance (45 times). They were stable in drug-free medium for 6 months, and showed no cross-resistance with other antileishmanial drugs. Rhodamine uptake and efflux were studied. They were not modified in the resistant strain, indicating the absence of P-glycoprotein overexpession. The effect of atovaquone on membrane lipidic composition was determined in both WT and atovaquone-resistant promastigotes. Analysis of lipid composition of the atovaquone-resistant strain showed that sterol biosynthesis was decreased in atovaquone-resistant parasites. Cholesterol was found to be the major membrane sterol as opposed to the WT strain. Cholesterol, due to its ordering effect, could decrease membrane fluidity and subsequently block the passage of atovaquone through the membrane. Increased membrane cholesterol content and altered drug membrane fluidity resulted from possible decrease of ergosterol biosynthesis by atovaquone, incorporation of cholesterol by promastigotes in the culture medium, solubilisation of atovaquone by cholesterol and co-passage of the two compounds or influence of dimethylsulfoxide. These results indicate that different cellular alterations may participate in the resistant phenotype, by altering drug membrane permeability.

Ex vivo purging by adenoviral p53 gene therapy does not affect NOD-SCID repopulating activity of human CD34+ cells

Co-incubation of a replication-deficient, recombinant adenovirus carrying the wild-type p53 gene (rAd-p53) and hematopoietic stem cell (HSC) products from patients with breast cancer can significantly reduce tumor cell contamination. Whereas this approach provides a powerful tumor cell purging strategy, potential detrimental effects on the HSC population have not been investigated. The ability of human HSC to reconstitute hematopoiesis in severe combined immunodeficient (SCID) mice and to undergo secondary transplantation provides the only nonclinical measure of self-renewing, stem cell function. The objective of this study was to investigate whether co-incubation with rAd-p53 compromised the SCID repopulating activity (SRA) of HSC. Granulocyte colony-stimulating factor-mobilized human CD34+ cells were co-cultured with rAd-p53 at our targeted clinical dose, and the ability of these cells to establish multilineage hematopoiesis in sublethally irradiated, nonobese diabetic (NOD)-SCID mice was investigated. The persistence of human cells in the mice was investigated by flow cytometry, granulocyte-macrophage colony-forming unit assay, and polymerase chain reaction of human Alu sequences. Further, limiting dilution analysis provided a quantitative comparison between the SRA of CD34+ cells co-incubated with rAd-p53 and control CD34+ cells (no rAd-p53 co-incubation). We conclude that co-incubation with rAd-p53 has little effect on the SRA of HSC.

Laryngostroboscopic, acoustic, and environmental characteristics of high-risk vocal performers

Vocal performance often requires excessively high vocal demand. In particular "high-risk" performers, a group of individuals who use their voices at their maximum effort level, are often exposed to unique vocal abuse characteristics which include high environmental and performance demands and inconsistencies of cast performance. Three categories of high-risk performers were studied: musical theater, choral ensemble, and street theater. Musical theater performers produce a Broadway, West End "belting" style voice. Street theater performers use a high-energy pitch varying dialogue in order to imitate a desired character voice. Choral ensemble performance requires group cohesion and blending of four-part harmony. The melodies require sustained vocal durations within each of the respective registers. For each of these studied groups vocal tasks of sustained production of /i/ and /a/ were subjected to analysis. Acoustic measures included fundamental frequency, standard deviation of fundamental frequency, jitter percent, shimmer percent, and noise-to-harmonic ratio. Laryngostroboscopic parameters were assessed during sustained /i/. Environmental acoustic sound field measurements were made using an A weighting and linear weighting sound pressure level. These weightings were used to describe noise levels and vocal output, respectively, within the performance environments. Results of the analysis suggest that high-risk performers are a unique performance type defined by distinctive, acoustic, laryngostroboscopic, and environmental characteristics.

Crc is involved in catabolite repression control of the bkd operons of Pseudomonas putida and Pseudomonas aeruginosa

Crc (catabolite repression control) protein of Pseudomonas aeruginosa has shown to be involved in carbon regulation of several pathways. In this study, the role of Crc in catabolite repression control has been studied in Pseudomonas putida. The bkd operons of P. putida and P. aeruginosa encode the inducible multienzyme complex branched-chain keto acid dehydrogenase, which is regulated in both species by catabolite repression. We report here that this effect is mediated in both species by Crc. A 13-kb cloned DNA fragment containing the P. putida crc gene region was sequenced. Crc regulates the expression of branched-chain keto acid dehydrogenase, glucose-6-phosphate dehydrogenase, and amidase in both species but not urocanase, although the carbon sources responsible for catabolite repression in the two species differ. Transposon mutants affected in their expression of BkdR, the transcriptional activator of the bkd operon, were isolated and identified as crc and vacB (rnr) mutants. These mutants suggested that catabolite repression in pseudomonads might, in part, involve control of BkdR levels.

Domain-engineered pyroelectric radiometer

We built a large-area domain-engineered pyroelectric radiometer with high spatial and spectral response uniformity that is an excellent primary transfer standard for measurements in the near- and the mid-infrared wavelength regions. The domain engineering consisted of inverting the spontaneous polarization over a 10-mm-diameter area in the center of a uniformly poled, 15.5 mm x 15.5 mm square, 0.25-mm-thick LiNbO(3) plate. Gold black was used as the optical absorber on the detector surface, and an aperture was added to define the optically sensitive detector area. Our results indicate that we significantly reduced the acoustic sensitivity without loss of optical sensitivity. The detector noise equivalent power was not exceptionally low but was nearly constant for different acoustic backgrounds. In addition, the detector's spatial-response uniformity variation was less than 0.1% across the 7.5-mm-diameter aperture, and reflectance measurements indicated that the gold-black coating was spectrally uniform within 2%, from 800 to 1800 nm. Other detailed evaluations of the detector include detector responsivity as a function of temperature, electrical frequency response, angular response, and field of view.

Imaging evaluation of suspected pulmonary embolism

Venous thromboembolism (VTE) is a common disorder that is difficult to diagnose clinically but carries significant morbidity and mortality if untreated. Additionally, although demonstrated to be of benefit in cases of proven deep vein thrombosis (DVT) and pulmonary embolism (PE), anticoagulation therapy is not without risk. Because the clinical exam is known to be unreliable for the detection of both DVT and PE, many imaging modalities have been used in the diagnostic imaging algorithm for the detection of VTE, including chest radiography, ventilation/perfusion (V/Q) scintigraphy, pulmonary angiography, and recently, spiral computed tomography (CT) and magnetic resonance imaging (MRI). Chest radiographic findings in acute PE include focal oligemia, vascular enlargement, atelectasis, pleural effusions, and air space opacities representing pulmonary hemorrhage or infarction. The chest radiograph can occasionally be suggestive of PE but is more often nonspecifically abnormal. The main use of the chest radiograph in the evaluation of suspected PE is to exclude entities that may simulate PE and to assist in the interpretation of V/Q scintigraphy. Lower extremity venous compression ultrasonography (CU) is both sensitive and specific for the diagnosis of femoropopliteal DVT, and the value of negative CU results has been established in outcomes studies. However, the reliability of CU for the detection of isolated calf vein thrombosis is not well established, and the clinical significance of such thrombi is debatable. Additional methods such as color and spectral Doppler analysis are also useful in the diagnostic evaluation of DVT but are best considered as adjuncts to the conventional CU examination rather than as primary diagnostic modalities themselves. Compression ultrasonography and Doppler techniques are useful in the evaluation of suspected upper extremity DVT; spectral Doppler waveform analysis is particularly useful to assess for the patency of veins that cannot be directly visualized and compressed with conventional gray-scale sonography. V/Q scintigraphy has been the initial modality obtained in patients suspected of PE for a number of years. Although many studies have investigated the role of V/Q scintigraphy in the evaluation of VTE, the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study has provided the most useful information regarding the utility of V/Q scintigraphy in this setting. A high probability scan interpretation is sufficient justification to institute anticoagulation, and a normal perfusion scan effectively excludes the diagnosis of PE. A normal/near normal scan interpretation also carries a sufficiently low prevalence of angiographically proven PE to withhold anticoagulation. Although the prevalence of PE in the setting of low probability scan interpretations is low and several outcomes studies have demonstrated a benign course in untreated patients with low probability scan results, patients with inadequate cardiopulmonary reserve do not necessarily have good outcomes. Such patients deserve more aggressive evaluation. Patients with intermediate probability scan results have a 20% to 40% prevalence of angiographically proven PE and thus require further investigation. The radionuclide investigation of DVT includes such techniques as radionuclide venography and thrombus-avid scintigraphy. Although these methods have not been as thoroughly evaluated as CU, studies thus far have indicated encouraging results, and further investigations are warranted. Pulmonary angiography has been the gold standard for the diagnosis of PE for decades. Studies have indicated that angiography has probably been underutilized by referring physicians for the evaluation of suspected PE, likely because of the perception of significant morbidity and mortality associated with the procedure. (ABSTRACT TRUNCATED)

The increased need for a permanent pacemaker after reoperative cardiac surgery

OBJECTIVE

The requirement for permanent pacemaker implantation after most initial cardiac surgical procedures generally is less than 3%. To identify the incidence and factors related to permanent pacemaker need after repeat cardiac surgery, we retrospectively studied 558 consecutive patients undergoing at least one repeat cardiac operation.

METHOD

Univariable and multivariable analyses of comorbidity, preoperative catheterization values, and operative data were performed to identify factors related to pacemaker implantation.

RESULTS

In this group, 54 patients (9.7%) required a permanent pacemaker. A multivariable model showed a relationship between a permanent pacemaker and tricuspid valve replacement/annuloplasty associated with aortic/mitral valve replacement, preoperative endocarditis, increasing number of reoperations, the degree of hypothermia during cardiopulmonary bypass, and advanced age. Additional univariable predictors of pacemaker need included multiple valve replacement, increased cardiopulmonary bypass and aortic crossclamp times, and aortic valve replacement. Over 90% of patients who have or have not received permanent pacemaker implantation were in New York Heart Association class I to II, with a mean follow-up time of 6 years. Kaplan-Meier survival curves were statistically similar for both groups at 5 and 10 years after the operation.

CONCLUSION

Permanent pacemaker implantation was required in 9.7% of patients undergoing repeat cardiac surgery. This represented approximately a fourfold increase compared with similar primary operations reported in other series. Factors strongly related to this need included valve replacement, preoperative endocarditis, number of reoperations, advanced age, and degree of hypothermia during cardiopulmonary bypass. The need for a permanent pacemaker after reoperations did not result in significant long-term impairment of functional status or longevity compared with those who did not require a permanent pacemaker.

Internal jugular vein patency after functional neck dissection: venous duplex imaging

We present a retrospective study performed to determine jugular patency after functional neck dissection (FND). Twenty-six patients, 16 females and 10 males, ranging in age from 16 to 78 were examined. These patients underwent either unilateral FND or bilateral FND for cervical lymph node metastases. Cervical duplex and pulsed Doppler imaging were chosen to determine internal jugular vein (IJV) patency. The examination was performed after a minimum postoperative period of 2 months and a maximum one of 22 years. Thirty-one IJVs were examined. All but 4 IJVs examined were found patent postoperatively. The preservation rate of patency of the IJV in FND was found to be high (27 of 31 or 87%). These results favor the use of FND for IJV preservation, particularly in bilateral neck dissection.

Postoperative cellulitis of the foot and lower leg following coronary bypass

Greater saphenous vein grafts are standardly used for coronary artery bypass grafting. Recurrent acute cellulitis of the saphenous vein-donor extremity is an infrequently reported complication. The authors present a protocol designed to reduce the incidence of the recurrent cellulitis through proper preoperative assessment and postoperative management.

[Spontaneous external biliary fistula]

Spontaneous biliary cutaneous fistula is a rare complication of inflammatory perforation of the gallbladder. We describe a 70-year-old woman who developed a fistula between the gallbladder and the skin following drainage of an abdominal wall abscess. In such cases primary drainage of the abscess alone is advisable. Only after the active infection has subsided should definitive cholecystectomy and excision of the fistulous tract be carried out.

Achievement correlates of the Woodcock-Johnson Reading and Mathematics Subtests, KeyMath, and Woodcock Reading in an elementary aged learning disabled population

Thirty-two elementary aged learning-disabled students were administered the math and reading subtests from the Woodcock-Johnson Psycho-Educational Battery, KeyMath, and Woodcock Reading Mastery Tests. Grade equivalent scores and standard scores were compared and yielded significant correlations that range from .79 to .93. Mean grade equivalent scores did however significantly differ for the two reading measures but not when standard scores were used. The two math indices yielded nonsignificant grade equivalent scores. Similarities and differences between the instruments are discussed in relation to enhancing the identification of learning disabilities.

Characterization of phi 6 mutants that are temperature sensitive in the morphogenetic protein P12

P12 is a morphogenetic protein necessary for the envelopment of the bacteriophage phi 6 nucleocapsid with the viral membrane. Gene 12 is located along with three other genes on the smallest chromosome of the virion. ts mutants in P12 were obtained by first characterizing the isoelectric focusing behavior of phi 6 proteins and then screening ts mutants of phi 6 that had previously been assigned to chromosome C for changes in the behavior of P12. In this manner, three independently isolated mutants were identified and were found to have morphogenetic consequences at restrictive temperatures similar to gene 12 nonsense mutants in nonsuppressor cells in that only unenveloped nucleocapsids were formed. When infected cells were labeled at restrictive temperature, 27 degrees, and then shifted to 21 degrees, normal phage particles were formed; however, the hydrophobic membrane proteins in the particles were not labeled, indicating that functional P12 must be present at the time of synthesis of the membrane proteins for them to assemble into virions or that the defective P12 leads the membrane proteins into a nonfunctional pathway.

Electrical stimulation in exercise of the quadriceps femoris muscle

Thirty-seven healthy subjects took part in an investigation to determine if the application of electrical stimulation to normal muscle, in combination with exercise, augments strength. Subjects were divided into three groups. Grwoup A (n = 14) was a control group (no exercise, no electrical stimulation). Group B members (n = 11) engaged in 10 sessions of maximum isometric exercise, and Group C subjects (n = 12) performed 10 sessions of maximum isometric exercise while simultaneously receiving electrical stimulation. The knee extensor muscles of subjects in Groups B and C increased in strength. However, the strength gains for Groups B and C were equivalent, suggesting that electrical stimulation combined with maximum isometric contractions has no greater effect on enhancing strength than does conventional static exercise.