Investigating dilution ventilation control strategies in a modern U.S. school bus in the context of the COVID-19 pandemic.

Fresh air ventilation has been identified as a widely accepted engineering control effective at diluting air contaminants in enclosed environments. The goal of this study was to evaluate the effects of selected ventilation measures on air change rates in school buses. Air changes per hour (ACH) of outside air were measured using a well-established carbon dioxide (CO2) tracer gas decay method. Ventilation was assessed while stationary and while traversing standardized route during late autumn/winter months in Colorado. Seven CO2 sensors located at the driver's seat and at passenger seats in the front, middle, and rear of the bus yielded similar and consistent measurements. Buses exhibited little air exchange in the absence of ventilation (ACH = 0.13 when stationary; ACH = 1.85 when mobile). Operating the windshield defroster to introduce fresh outside air increased ACH by approximately 0.5-1 ACH during mobile and stationary phases. During the mobile phase (average speed of 23 miles per hour (mph)), the combination of the defroster and two open ceiling hatches (with a powered fan on the rear hatch) yielded an ACH of approximately 9.3 ACH. A mobile phase ACH of 12.4 was achieved by the combination of the defroster, ceiling hatches, and six passenger windows open 2 inches in the middle area of the bus. A maximum mobile phase ACH of 22.1 was observed by using the defroster, open ceiling hatches, driver window open 4 inches, and every other passenger window open 2 inches. For reference, ACHs recommended in patient care settings where patients are being treated for airborne infectious diseases range from 6 to ≥12 ACHs. The results indicate that practical ventilation protocols on school buses can achieve air change rates thought to be capable of reducing airborne viral transmission to the bus driver and student passengers during the COVID-19 pandemic.

Predicting distress among people who care for patients living longer with high-grade malignant glioma.

PURPOSE: Caregivers of patients living longer with high-grade malignant glioma (HGG) have the unique challenge of caring for a person who may have cognitive impairment, along with cancer-related issues over a prolonged period of time. This study aims to detail the psychosocial profile of long-term caregivers, to describe their perceptions of the patient's quality of life and to examine predictors of their psychological distress. METHODS: Sixty-nine caregivers (48%) of eligible patients with HGG surviving over 2 years were recruited from two Australian metropolitan tertiary hospitals. Caregivers completed cross-sectional measures of psychological distress (GHQ-12), caregiver impact (FACQ-PC) and patient functional well-being (FACT-Br TOI). Correlational analyses identified factors related to caregiver psychological distress. Those of significance (p ≤ .01) were examined using multiple regression models to determine their predictive value. RESULTS: Caregivers were mostly female (73%), spouses (67%), cohabiting (78%) and were caring for patients surviving a median of 5.9 years since diagnosis. Whilst caregivers overall reported minimal psychological distress, 28% endorsed moderate to severe psychological distress, warranting clinical attention. Caregiver strain and low patient functional well-being both significantly predicted caregiver psychological distress (adjusted R(2) = .35, F(4, 60) = 17.7, p < .001), accounting for a moderate amount (35%) of variance. Other typical factors such as duration of caregiving, performance status, symptom burden and disease or demographic related factors were not predictive. CONCLUSIONS: Psychological distress affects a significant proportion of caregivers of patients living longer with HGG. The presence of caregiver strain and low patient functional well-being are the most important predictors of psychological distress among this cohort of caregivers.

Primary melanoma of the cochlea with cerebellopontine extension and leptomeningeal spread.

BACKGROUND: Less than 1 per cent of tumours occurring in the region encompassing the internal auditory canal and the cerebellopontine angle are malignant. Primary central nervous system melanomas arising from this region are exceptionally rare and are often initially misdiagnosed as acoustic neuromas. METHODS: We present a 71-year-old man with acute vestibular disturbance and unilateral hearing loss. Magnetic resonance imaging demonstrated a mass, thought to be a cochlear nerve schwannoma, involving the cochlea and the internal auditory canal. At surgery, a pigmented mass adherent to the facial nerve was visualised, and the observed histopathology was consistent with a malignant melanoma. No extracranial site for the primary tumour was found, suggestive of a primary central nervous system melanoma. RESULTS: Despite surgical resection and adjuvant radiotherapy, the patient re-presented with extensive leptomeningeal disease 16 months later. CONCLUSION: Malignant tumours in the internal auditory canal and cerebellopontine angle region are rare. Early diagnosis and management are aided by recognition of characteristic factors such as a history of prior malignancy, atypical magnetic resonance imaging findings and accelerated audiovestibular symptoms. Despite the presented patient's outcome, total surgical resection with post-operative radiotherapy remains the recommended treatment.

Factors associated with symptom-specific psychological and functional impact among acoustic neuroma patients.

INTRODUCTION: The main purpose of this study was to investigate the psychological and functional impact attributed to acoustic neuroma symptoms. MATERIALS AND METHODS: A sample of 207 acoustic neuroma patients completed a study-specific questionnaire about the severity, frequency, and psychological and functional impact of 9 acoustic neuroma symptoms. RESULTS: The survey response rate was 56.4 per cent. All symptoms had some degree of psychological impact for the majority of participants; hearing loss was the symptom most often reported to have a severe psychological impact. The majority of respondents reported functional impact attributed to hearing loss, balance disturbance, dizziness, eye problems, headache and fatigue; balance disturbance was the symptom most often reported to have a severe functional impact. For most symptoms, psychological and functional impact were related to severity and frequency. CONCLUSION: Of the acoustic neuroma symptoms investigated, hearing loss and balance disturbance were the most likely to have a severe psychological and functional impact, respectively.

Stereotactic radiosurgery for treatment of Cushing disease: an Australian experience.

Stereotactic radiation therapy has emerged as an alternative to conventional radiotherapy for treatment of Cushing disease. The aim of this study was to investigate the efficacy and safety of this treatment. Records of patients with Cushing disease treated with stereotactic radiation were reviewed. Seventeen patients underwent stereotactic radiosurgery. Ten achieved remission after a mean of 23 (95% confidence interval, 15-31) months, and two developed hormone deficiencies.

Factors associated with anxiety and depression in the management of acoustic neuroma patients.

The objectives of this study were to describe anxiety and depression levels among acoustic neuroma patients; examine differences in anxiety and depression across the acoustic neuroma management options of microsurgery, radiation and observation; and to investigate management, medical and demographic factors that might predict anxiety and depression in this patient group. A cross-sectional questionnaire was completed by 205 adults diagnosed with, or treated for, a unilateral acoustic neuroma within five years of questionnaire distribution. Median age of participants was 57.0 years, and 120 (58.5%) were female. Anxiety and depression were measured using the Hospital Anxiety and Depression Scale (HADS). Clinically significant anxiety was reported by 29.8% of participants and 10.2% were depressed. Mean anxiety and depression scores did not differ from general population norms. No significant differences in anxiety and depression were found across management options. Time since management, number of symptoms and comorbid medical conditions predicted anxiety, while depression was predicted by number of symptoms. This appears to be the first study among acoustic neuroma patients in which anxiety and depression were compared across management options. Treating physicians should be aware that as the number of acoustic neuroma symptoms increases, so may the likelihood of clinically significant anxiety and depression.

Radiotherapy management of patients diagnosed with glioma in Victoria (1998-2000): a retrospective cohort study.

This study aimed to describe the radiotherapy (RT) management and subsequent outcome in a cohort of patients with newly diagnosed glioma. Treatment details were obtained via a questionnaire completed by neurosurgeons, radiation and medical oncologists who treated patients diagnosed with glioma in Victoria during 1998-2000. Patients were identified by using the population-based Victorian Cancer Registry. Over the study period, data on 828 patients were obtained, of whom 612 (74%) were referred for consideration of RT. Radiotherapy was given to 496 patients as part of their initial treatment and to an additional 10 patients at the time of tumour recurrence or progression. The median age was 72 (16-85) years. Median overall survival (OS) was 9.2 (standard error (SE) 0.6) months for the entire group. Median OS was 29.1 (SE 8.0) and 7.4 (SE 0.4) months for all patients with histological confirmation of World Health Organization Grades III (anaplastic astrocytoma) and IV (glioblastoma multiforme) histology, respectively. A total of 47 different RT dose fractionation schedules were identified. This is the largest survey detailing management of glioma with RT, published to date. A marked variation in dose fractionation schemes was evident. While current best practice involves the use of chemotherapy in conjunction with RT for glioblastoma multiforme, advances in patient care may be undermined by this variation in the use of RT. Clinical trials relevant to an ageing population and evidence-based national clinical guidelines are required to define best practice.

Preparing to sit the Royal Australia and New Zealand College of Radiologists Faculty of Radiation Oncology Fellowship Part 2 examination: the value of a workshop including practice and feedback.

A workshop has been held annually to help prepare candidates to sit the Royal Australia and New Zealand College of Radiologists Part 2 Faculty of Radiation Oncology examination. This study examined the value of such a course and its component parts and assessed attendees' learning environments. We collected detailed information from participants before and after the training workshop in 2005. A specific feature of this workshop included the use of an examination technique feedback form to facilitate the provision of systematic and comprehensive feedback to individual candidates after mock examination. Participants completed course evaluation forms and a learning environment survey. There were 22 candidate participants. The course and its components of this course were perceived very positively - including the examination technique feedback forms and written advice. Only three of the 24 questions regarding the registrars learning environment had less than 80% favourable responses - two of these questions related to workload. The course design described seems reasonably satisfactory in that it included the components ranked most highly by candidates. We also identified a number of variations that may be useful for future workshops. Although learning environments were generally good, we identified a perceived problem with workloads affecting a significant number of registrars.

Enhanced skeletal growth of sheep heterozygous for an inactivated fibroblast growth factor receptor 3.

Normal fibroblast growth factor receptor 3 (FGFR3) acts as a negative bone growth regulator by restricting chondrocyte proliferation and endochondral bone elongation. In sheep, a heritable mutation that inactivates FGFR3 produces skeletal overgrowth when homozygous, this condition is commonly referred to as spider lamb syndrome (SLS). We hypothesized that sheep heterozygous for the inactivated FGFR3 mutation (FGFR3(SLS/+)) would exhibit enhanced long bone growth and greater frame size; additionally, the isolated effects of increased bone growth would translate into greater BW and larger LM area relative to normal lambs at harvest. The current study investigated bone length and LM area of FGFR3(SLS/+) sheep at maturity and during growth. At maturity, FGFR3(SLS/+) ewes exhibited a larger frame size and longer bones than normal FGFR3(+/+) ewes (P < 0.05). Similarly, FGFR3(SLS/+) lambs had greater frame sizes than normal FGFR3(+/+) lambs, as indicated by increased metacarpal III length and height at withers (P < 0.05). The FGFR3(SLS/+) lambs took longer than the normal FGFR3(+/+) lambs to reach the 60-kg common BW harvest end point (P < 0.05). The FGFR3(SLS/+) lambs showed no difference in BW, ADG, or LM area at any age compared with normal FGFR3(+/+) lambs (P > 0.2). A similar LM area produced in the context of a greater frame size and skeletal length produces a greater muscle volume, thereby potentially increasing meat yield. The results of this study suggest that FGFR3(SLS/+) animals exhibit a relaxation of the normal inhibition of chondrocyte proliferation, resulting in an increase in the overall frame size. The sheep industry could utilize the naturally occurring genetic mutation in FGFR3 to potentially increase meat yields with enhanced skeletal growth as an alternative to exogenous growth promotants.

Passive immunization of rams (Ovis aries) against GnRH: effects on antibody titer, serum concentrations of testosterone, and sexual behavior.

The effect of immunoneutralization of gonadotropin-releasing hormone (GnRH) on serum concentrations of testosterone and sexual behavior was evaluated in sexually mature male sheep. In Experiment 1, GnRH1 rams (n=16) were passively immunized against GnRH (300 ml antiserum), control rams were either passively immunized against keyhole limpet hemocyanin (KLH, n=15) or surgically castrated (Wethers1, n=4). Sexual performance of the rams was assessed weekly for 3 weeks before and 6 weeks after immunization, using ovarihystertomized ewes actively immunized against GnRH. Experiment 2 evaluated the effects of repeated immunization. Rams were immunized with two aliquots (400 and 300 ml, respectively) of anti-GnRH sera (GnRH, n=5) or normal sheep serum (NSS, n=4), 2 weeks apart. Surgically castrated animals were used as a second control group (Wethers2). Administration of anti-GnRH sera, but neither anti-KLH nor NSS sera, resulted in marked reduction (P<0.05) in serum concentrations of testosterone. Sexual behavior was not consistently affected by administration of one aliquot of anti-GnRH sera, however repeated immunizations resulted in more persistent reduction in serum concentrations of testosterone and more consistent suppression of sexual behavior.

Do sire-dam interactions contribute significantly to fertility comparisons in heterospermic insemination trials.

The percentage of offspring sired after heterospermic insemination of equal numbers of spermatozoa is believed to be a very sensitive measure of relative in vivo fertility of the inseminated samples. The objective of these trials was to evaluate whether there was a detectable male-female interaction in the fertilizing ability of spermatozoa. If there was such an interaction, we reasoned that the paternity of offspring from individual females in a heterospermic trial the second year would be similar to the paternity of offspring in the same individual females the first year if the same ejaculates were used. Five groups of ewes were inseminated with different combinations of semen (a single Merino ejaculate from one of five rams randomly paired with five different pools of Suffolk semen) in a heterospermic trial. Those ewes conceiving the first year were inseminated in a second breeding season with the same combination of semen used previously. The percentage of lambs sired by each ejaculate/pool of ejaculates was calculated for all lambs born from all ewes inseminated with each semen combination. These percentages would be the expected ratios of Merino-sired:Suffolk-sired lambs if there is no male-female interaction. Ewes in each group were divided into two subgroups: those conceiving only Merino-sired lambs the first year and those conceiving at least one Suffolk-sired lamb the first year. The ratio of Merino-sired lambs:Suffolk-sired lambs did not differ in either subgroup from those expected if there was no male-female interaction. These results are consistent with the absence of a male-female interaction in relative fertilizing ability of spermatozoa.

Artificial selection of rams for sexual performance and its effect on the sexual behavior and fecundity of male and female progeny.

The objective of this study was to determine the effect of a single generation of artificial selection for sexual performance in rams on the sexual behavior and fecundity of their male and female progeny. Ninety-two ram lambs born to sires selected for either high or low sexual performance were evaluated for their sexual behaviors at approximately 8 months of age when individually exposed to four estrous ewes for 30min in four weekly serving capacity tests. Number of mounts and successful matings (ejaculations) were recorded. Fourteen of the 17 high-performing ram lambs identified were sired by high-performing sires, whereas 22 of 37 low-performing ram lambs were sired by low-performing sires (P<0.01). Sons of high-performing sires exhibited more ejaculations (P<0.04) and more mounts without ejaculation (P<0.02) than sons of low-performing sires. The two groups of ram lambs did not differ in mating efficiency (ratio of ejaculations to total mounts). Daughters of high-performing rams (N=79) exhibited their first behavioral estrus approximately 8 days earlier than daughters (N=61) of low-performing sires (P<0.005). Ovulation rates for the two groups of ewe lambs did not differ (P=0.55). It was concluded that there was sufficient genetic variation in the population of sheep studied to obtain a significant response to selection for ram sexual performance in both male and female offspring in a single generation.

Australian high-dose-rate brachytherapy protocols for gynaecological malignancy.

There is no consensus over the optimal dose fractionation schedules for high-dose-rate (HDR) brachytherapy used for gynaecological malignancy. In Australian public hospital departments of radiation oncology, HDR brachytherapy for gynaecological cancer is being more commonly used. A survey of public departments that are using this technology, or that plan to introduce this technology, was performed. Their current protocols are presented. In general, protocols are similar biologically; however, the practical aspects such as the number of fractions given do vary and may reflect resource restrictions or, alternatively, differences in interpretations of the literature and of the best protocols by clinicians.

A double exposed portal image comparison between electronic portal imaging hard copies and port films in radiation therapy treatment setup confirmation to determine its clinical application in a radiotherapy center.

PURPOSE: At the William Buckland Radiotherapy Center (WBRC), field-only electronic portal image (EPI) hard copies are used for radiation treatment field verification for whole brain, breast, chest, spine, and large pelvic fields, as determined by a previous study. A subsequent research project, addressing the quality of double exposed EPI hard copies for sites where field only EPI was not considered adequate to determine field placement, has been undertaken. The double exposed EPI hard copies were compared to conventional double exposed port films for small pelvic, partial brain, and head and neck fields and for a miscellaneous group. METHODS AND MATERIALS: All double exposed EPIs were captured during routine clinical procedures using liquid ion chamber cassettes. EPI hard copies were generated using a Visiplex multi-format camera. In sites where port film remained the preferred verification format, the port films were generated as per department protocol. In addition EPIs were collected specifically for this project. Four radiation oncologists performed the evaluation of EPI and port film images independently with a questionnaire completed at each stage of the evaluation process to assess the following: Adequacy of information in the image to assess field placement. Adequacy of information for determining field placement correction. Clinician's preferred choice of imaging for field placement assessment RESULTS: The results indicate that double exposed EPI hard copies generally do containsufficient information to permit evaluation of field placement and can replace conventionaldouble exposed port films in a significant number of sites. These include the following:pelvis fields < 12 X 12 cm, partial brain fields, and a miscellaneous group. However forradical head and neck fields, the preferred verification image format remained port film dueto the image hard copy size and improved contrast for this media. Thus in this departmenthard copy EPI is the preferred modality of field verification for all sites except radical headand neck treatments. This should result in an increase in efficiency of workloadmanagement and patient care.

Manipulating odor cues facilitates add-on fostering in sheep.

Manipulating the odor of a ewe's own and alien lambs has been used to facilitate fostering a second lamb on ewes with a single offspring (add-on fostering). Previous research has demonstrated that familiar odor cues must be present on the own and alien young to achieve successful and rapid adoptions. Familiar odors may consist of natural own-lamb odors or artificial odors previously applied to the lambs involved. In the present study (Exp. 1), an artificial odorant (neatsfoot oil) was applied to the own and alien lambs shortly after birth to establish a common familiar odor. Acceptance tests were conducted daily over a 72 h period. In Exp. 2, neatsfoot oil was again used as a common artificial odorant to facilitate add-on fostering, but, in addition, the natural odors of own and alien lambs were transposed by exchanging cloth stockinette jackets worn by the lambs. In Exp. 1, 9 of 18 ewes (50%) met the criteria for accepting their own and alien lambs within 72 h. Seven of these nine ewes (78%) accepted the alien lamb immediately. In Exp. 2, 24 of 30 ewes (80%) accepted their own and alien young, and 20 of the 24 acceptances (83%) were immediate. We conclude that add-on fostering may be limited only by our inability to properly match familiar-odor cues on own and alien lambs.

Repeated matings with individual ewes by rams differing in sexual performance.

Twenty-four sexually mature rams were individually exposed to 10 estrous ewes on three occasions to determine the relationship between levels of sexual performance (ejaculation rate or serving capacity) and the incidence of repeated matings (ejaculations) with individual ewes. Rams that attained six ejaculations in a relatively short period of time (HP rams) mated fewer times with individual ewes than low-performing (LP) rams (P < .01). As a consequence, HP rams tended to mate with a greater number of different ewes than did LP rams (P < .06). In addition, time required to attain six ejaculations was inversely correlated with the number of different ewes mated (P < .03). The HP rams did not differ from LP rams in the number of different ewes investigated and courted. These findings highlight the value of using rams with relatively rapid ejaculation rates when breeding large groups of naturally cycling or synchronized ewes.

Heterotopic bone formation affecting the hip joint is preventable in high risk patients by post-operative radiation.

Between 1984 and 1993, 40 high risk patients (45 hips) received postoperative irradiation as prophylaxis against heterotopic ossification (HO). Radiotherapy was commenced within 5 days of the surgery in 43 of 45 hips. The development of HO was assessed by comparison of radiographic films prior to irradiation and at least 2 months after treatment (median interval 12 months). Progression of HO was observed in only two of 45 hips (4.3%) and of clinical significance in one (2.2%). Treatment was well tolerated with no acute complications or loosening of prosthetic components attributable to irradiation. During the study period, the treatment programme changed from 20 Gy in 10 fractions to 6-8 Gy in a single fraction, without loss of treatment efficacy. As well as improving resource utilization, single fraction techniques allow fewer patient transfers thereby reducing patient discomfort and risk of hip dislocation. This procedure is uncomplicated and should be considered more widely in the management of this disabling non-malignant condition.

In vitro fertility evaluation of cryopreserved ram semen and its correlation with relative in vivo fertility.

The present study was designed to evaluate zona-free hamster ova assay conditions for cryopreserved ram semen and to investigate the correlation between ability to penetrate zona-free hamster ova and in vivo fertility. In vivo fertility was estimated for cryopreserved semen from 5 Merino rams using heterospermic insemination. Equal numbers of postthaw motile spermatozoa from a Merino ejaculate and pooled Suffolk ejaculates were mixed prior to insemination. Each Merino ejaculate was paired with the same pool of cryopreserved Suffolk semen. Relative in vivo fertility for each Merino ram was calculated as the proportion of offspring that were sired by the Merino (range 42 to 100%). These ejaculates also differed in their ability to penetrate zona-free-hamster ova (3.6 to 9.0 penetrated spermatozoa per ovum). Differences in penetration rate were correlated with in vivo fertility (P < 0.002, R2 = 0.69). Results of these studies suggest that the zona-free hamster ova bioassay may be a useful test in the assessment of cryopreserved ram sperm fertility.

Objective decision-making following a portal film: the results of a pilot study.

PURPOSE: To discriminate between random and systematic treatment setup errors using portal films. METHODS AND MATERIALS: A bi-dimensional analytic techniques using multiple analyses of variance based on Hotelling's T2 statistics to derive numerical and graphical measures of daily portal film accuracy and precision has been trialed using 88 daily portal films from seven patients' treatment. RESULTS: A demonstration is provided of how a reasonable approximation of random variation from the intended (Simulator) field center, and systematic displacement of the mean position of the portal film centers may be derived from a minimum number of portal films. If a random error as great as 10 mm exists, at least six or seven portal films are considered necessary to reliably detect and quantify the size of a systematic error. CONCLUSION: Our results suggest that a modest systematic error could go undetected until the end of a 5 or 6 week course of treatment if only one portal film is obtained each week. A greater number of portal films should be performed during the first week of treatment to reduce the frequency of such errors. Efforts to separate and quantify both random and systematic errors in setup are worthwhile and will lead to improvements in outcome at the individual patient level and at a departmental level in the development of quality assurance programs.