Women at Altitude: Menstrual-Cycle Phase, Menopause, and Exogenous Progesterone Are Not Associated with Acute Mountain Sickness

Gardner, Laurel, Linda E. Keyes, Caleb Phillips, Elan Small, Tejaswi Adhikari, Nathan Barott, Ken Zafren, Rony Maharjan, and James Marvel. Women at altitude: Menstrual-cycle phase, menopause, and exogenous progesterone are not associated with acute mountain sickness. High Alt Med Biol. 00:000-000, 2024. Background: Elevated progesterone levels in women may protect against acute mountain sickness (AMS). The impact of hormonal contraception (HC) on AMS is unknown. We examined the effect of natural and exogenous progesterone on the occurrence of AMS. Methods: We conducted a prospective observational convenience study of female trekkers in Lobuche (4,940 m) and Manang (3,519 m). We collected data on last menstrual period, use of exogenous hormones, and development of AMS. Results: There were 1,161 trekkers who met inclusion criteria, of whom 307 (26%) had AMS. There was no significant difference in occurrence of AMS between women in the follicular (28%) and the luteal (25%) phases of menstruation (p = 0.48). The proportion of premenopausal (25%) versus postmenopausal women (30%) with AMS did not differ (p = 0.33). The use of HC did not influence the occurrence of AMS (HC 23% vs. no HC 26%, p = 0.47), nor did hormonal replacement therapy (HRT) (HRT 11% vs. no HRT 31%, p = 0.13). Conclusion: We found no relationship between menstrual-cycle phase, menopausal status, or use of exogenous progesterone and the occurrence of AMS in trekkers and conclude that hormonal status is not a risk factor for AMS. Furthermore, women should not be excluded from future AMS studies based on hormonal status.

February 14th

This narrative recounts a medical resident's experience with a patient's desire to not receive life sustaining treatment. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Utility of PSMA PET Guided Metastasis-Directed Radiotherapy

PURPOSE/OBJECTIVE(S)

Metastasis-directed radiotherapy (MDT) is becoming a mainstay in the management of oligometastatic prostate cancer (PCa), and PSMA-PET is currently the most sensitive imaging modality for PCa metastasis screening. The efficacy of MDT guided by PSMA-PET imaging has not yet been well characterized. Moreover, the optimal role of androgen deprivation therapy (ADT) in the context of MDT is not known. We sought to assess the efficacy of PSMA PET-guided MDT in patients with metastatic PCa treated with and without ADT.

MATERIALS/METHODS

This is a single institutional retrospective study of patients diagnosed with metastatic prostate cancer by PSMA-PET imaging who were treated with MDT. Biochemical progression was defined as a PSA increase of ≥ 25% and ≥ 2 ng/mL if PSA was ≥ 2 ng/mL at time of initiating salvage treatment, or a PSA increase of ≥ 25% if PSA was < 2 ng/mL at time of salvage treatment. Survival analyses were performed using the Kaplan-Meier method with log-rank testing for significance. Cumulative incidence analyses were performed with Gray's testing for significance. Adverse event data were assessed per CTCAE v5 guidelines.

RESULTS

A total of 196 PSMA PET-avid lesions from 101 patients were irradiated with stereotactic body radiotherapy (SBRT). Median time from prior definitive locoregional therapy to MDT was 6.2 years. 79 patients had hormone-sensitive PCa (HSPC) and 22 patients had castration-resistant PCa (CRPC) at time of MDT. 47 of 79 (59%) patients with HSPC received ADT along with MDT, and 20 of the 47 patients received augmented ADT. 25 of the 32 (78%) HSPC patients receiving MDT without ADT had undergone at least one prior course of ADT, and none had castrate levels of testosterone at time of MDT with a median testosterone level of 341 ng/dl. With a median follow-up of 22.4 months, 5 of 196 lesions (2.6%) demonstrated radiographic progression. 2-year cumulative incidence of progression from HSPC to CRPC was 11% in patients who received ADT at time of MDT and 35% in those who did not (P = 0.027). Median biochemical progression free survival of patients with CRPC, HSPC treated without ADT, and HSPC treated with ADT following MDT was 5.4, 7.6, and 43.9 months respectively (P<0.0001). 2-year overall survival of the abovementioned groups was 72.2%, 100%, and 97.5% respectively (P<0.001). No Grade 3-5 adverse effects were observed.

CONCLUSION

MDT guided by PSMA-PET imaging is well-tolerated and delays biochemical progression in patients with CRPC and HSPC, with a greater effect observed in patients also receiving ADT.

Prior Ambulatory Mild Coronavirus Disease 2019 Does Not Increase Risk of Acute Mountain Sickness

Small, Elan, Caleb Phillips, William Bunzel, Lakota Cleaver, Nishant Joshi, Laurel Gardner, Rony Maharjan, and James Marvel. Prior ambulatory mild coronavirus disease 2019 does not increase risk of acute mountain sickness. High Alt Med Biol. 24:201-208, 2023. Background: Given its long-term morbidity, understanding how prior coronavirus disease 2019 (COVID-19) may affect acute mountain sickness (AMS) susceptibility is important for preascent risk stratification. The objective of this study was to examine if prior COVID-19 impacts risk of AMS. Materials and Methods: This was a prospective observational study conducted in Lobuje (4,940 m) and Manang (3,519 m), Nepal, from April to May 2022. AMS was defined by the 2018 Lake Louise Questionnaire criteria. COVID-19 severity was defined using the World Health Organization-developed criteria. Results: In the Lobuje cohort of 2,027, 46.2% of surveyed individuals reported history of COVID-19, with 25.7% AMS point-prevalence. There was no significant relationship between prior ambulatory mild COVID-19 and AMS (p = 0.6) or moderate AMS (p = 1.0). In the Manang cohort of 908, 42.8% reported history of COVID-19, with 14.7% AMS point-prevalence. There was no significant relationship between prior ambulatory mild COVID-19 and AMS (p = 0.3) or moderate AMS (p = 0.4). Average months since COVID-19 was 7.4 (interquartile range [IQR] 3-10) for Lobuje, 6.2 (IQR 3-6) for Manang. Both cohorts rarely exhibited moderate COVID-19 history. Conclusions: Prior ambulatory mild COVID-19 was not associated with increased risk of AMS and should not preclude high-altitude travel.

19-Year-Old with Sudden Onset Left Testicular Pain

CASE PRESENTATION

A previously healthy 19-year-old man presented to the emergency department with severe, sudden onset of left testicular pain. Physical exam revealed a left high-riding, horizontally oriented testicle without cremasteric reflex. Point-of-care ultrasound was used to confirm the diagnosis of testicular torsion, as well as to guide manual detorsion, verifying return of blood flow after reduction.

DISCUSSION

Testicular torsion is a urologic emergency in which testicular viability is time dependent. Point-of-care ultrasound can be an important and helpful tool to not only confirm suspicion but help guide adequacy of blood flow return after manual detorsion in conjunction with comprehensive ultrasound.

Older Age as a Predictive Risk Factor for Acute Mountain Sickness

BACKGROUND

Older populations are increasing and comprise a substantial portion of high-altitude travelers. Aging physiology may influence susceptibility to acute mountain sickness, though prior research remains inconclusive. The goal of this study was to investigate the relationship between increasing age and acute mountain sickness.

METHODS

This study was a pooled analysis of 5 prospective randomized controlled trials conducted at White Mountain, California from 2010, 2016-2019 with identical 4-hour rapid ascent from 1242 m to overnight sojourn at 3810 m. Acute mountain sickness was defined by the 2018 Lake Louise Questionnaire criteria.

RESULTS

There were 491 participants analyzed, 234 (48%) diagnosed with acute mountain sickness and 71 (14%) with moderate acute mountain sickness. Mean age was 37 years (±13). There was no significant correlation between Lake Louise Questionnaire severity and age (r = -0.02; 95% confidence interval [CI], -0.11-0.07, P = .7), 40-year-old dichotomy (t = -0.6; 95% CI, -0.53-0.28, P = .6), or decade of life (P = .4). Logistic regression found no increased odds of acute mountain sickness for increasing age by decade of life (odds ratio [OR] 1.0; 95% CI, 0.97-1.0) or 40-year-old dichotomy (OR 1.4; 95% CI, 0.97-2.1). A history of acute mountain sickness increased odds of acute mountain sickness (OR 3.2; 95% CI, 1.5-7.7).

CONCLUSIONS

Older age was not associated with incidence nor severity of acute mountain sickness. A history of altitude illness increased odds of acute mountain sickness and should be used for pre-ascent risk stratification.

Predictive Capacity of Pulmonary Function Tests for Acute Mountain Sickness

Small, Elan, Nicholas Juul, David Pomeranz, Patrick Burns, Caleb Phillips, Mary Cheffers, and Grant S. Lipman. Predictive capacity of pulmonary function tests for acute mountain sickness. High Alt Med Biol. 22: 193-200, 2021. Background: Pulmonary function as measured by spirometry has been investigated at altitude with heterogenous results, though data focused on spirometry and acute mountain sickness (AMS) are limited. The objective of this study was to investigate the capacity of pulmonary function tests (PFTs) to predict the development of AMS. Materials and Methods: This study was a blinded prospective observational study run during a randomized controlled trial comparing acetazolamide, budesonide, and placebo for AMS prevention on White Mountain, CA. Spirometry measurements of forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), and peak expiratory flow were taken at a baseline altitude of 1,250 m, and the evening of and morning after ascent to 3,810 m. Measurements were assessed for correlation with AMS. Results: One hundred three participants were analyzed with well-matched baseline demographics and AMS incidence of 75 (73%) and severe AMS of 48 (47%). There were no statistically significant associations between changes in mean spirometry values on ascent to high altitude with incidence of AMS or severe AMS. Lake Louise Questionnaire scores were negatively correlated with FVC (r = -0.31) and FEV₁ (r = -0.29) the night of ascent. Baseline PFT had a predictive accuracy of 65%-73% for AMS, with a receiver operating characteristic of 0.51-0.65. Conclusions: Spirometry did not demonstrate statistically significant changes on ascent to high altitude, nor were there significant associations with incidence of AMS or severe AMS. Low-altitude spirometry did not accurately predict development of AMS, and it should not be recommended for risk stratification.

A multicenter phase II study of abiraterone acetate (AA) in docetaxel pretreated castration-resistant prostate cancer (CRPC) patients (pts)

5047

Background: Despite castration, androgens remain critical to prostate cancer. Abiraterone acetate (AA) specifically and irreversibly inhibits CYP17, a key enzyme in androgen biosynthesis. Methods: 47 CRPC pts who had failed androgen deprivation therapy and had prior docetaxel chemotherapy received AA orally (1000mg QD) in 28 day cycles. Low dose glucocorticoids were allowed. Results: Patient demographics in table . Total maximal PSA declines with AA at any point on study of ≥30%, ≥50%, and ≥ 90% were observed in 32 (69%), 24 (51%) and 7 (15%) pts respectively. A similar trend in PSA response was seen at wk 12. 35 pts were evaluable by RECIST; 6 (17%) pts had a partial response and 23 (66%) pts had stable disease. 23% of pts showed ECOG improvement (PS 1 to 0 in 10 pts, PS 2 to 1 in 1 pt); 53% of pts maintained PS. Median duration on treatment was 167 days (95% CI 130–201). 17 pts received >6 cycles of AA; 8 pts received ≥ 12 cycles. Toxicities related to mineralocorticoid excess were mainly grade 1–2 (hypokalemia 51%; HTN 17%; edema 13%) and were treated with eplerenone or corticosteroids. Conclusions: AA has anti-tumor activity in these heavily pretreated pts, as evidenced by sustained PSA declines, improvement in PS and RECIST responses. A phase III trial assessing the efficacy and safety of AA and prednisone in CRPC pts who have failed docetaxel chemotherapy is underway.

[Table: see text]

[Table: see text]

Ixabepilone, mitoxantrone, and prednisone in patients with metastatic castration-resistant prostate cancer refractory to docetaxel-based therapy: A phase II study of the DOD Prostate Cancer Clinical Trials Consortium

5058

Background: Mitoxantrone (M) plus prednisone (P) and ixabepilone (Ix) each have modest, non cross-resistant activity as second line chemotherapy regimens in docetaxel-refractory patients with CRPC. These agents were therefore combined in a phase I study which demonstrated anti-cancer activity and defined the recommended phase II dose used in this trial. Methods: Patients with metastatic CRPC and progression after 3 or more cycles of docetaxel were enrolled in a phase II multicenter study of the combination of prednisone 5 mg BID, Ix (35 mg/m2) and M (12 mg/m2) administered intravenously on day 1 every 21 days, with pegfilgrastim (6 mg on day 2) support. Results: To date, 43 pts have been enrolled and have received a median of 4 cycles. Of 37 patients currently evaluable for response, 14 (38%; 95% CI: 22–55%) have had a confirmed ≥50% decline in PSA and 19 (51%; 95% CI 34–68%) have had a confirmed ≥30% decline in PSA. Two of 15 patients with evaluable measurable disease (13%) have had a RECIST-defined objective response. All 43 patients are evaluable for toxicity. Grade 3 or 4 neutropenia was seen in 6 pts (17%) and grade 3 or 4 thrombocytopenia was seen in 3 (8%). Nonhematologic grade 3/4 events possibly related to study drug have included grade 3 fatigue (3 pts), grade 3 pneumonia (2 pts), and grade 3 atrial fibrillation, grade 4 myocardial infarction, grade 4 prostatitis, grade 3 nausea/vomiting, grade 3 neuropathy, grade 3 elevated transaminases, grade 3 dizziness, grade 3 dehydration, grade 3 shortness of breath, and grade 4 vasovagal syncope (1 pt each). Grade 2 neuropathy has been seen in 4 patients. Conclusions: The Ix, M, P regimen is active as second-line therapy in CRPC patients with progressive disease after docetaxel therapy and is reasonably well tolerated. Further investigation of this regimen is warranted. This study was supported in part by CTEP/NCI and the DOD Prostate Cancer Clinical Trials Consortium.

[Table: see text]

Prostate cancer clinical trials consortium: A multicenter mechanism for the rapid design, development, and implementation of early phase clinical trials

e16065

Background: Leading investigators in prostate cancer have hypothesized that clinical trials (CT) are optimally conducted as multicenter studies. To test this, the Prostate Cancer Clinical Trials Consortium (PCCTC) was formed with support from the Prostate Cancer Foundation (PCF) and the Department of Defense Clinical Consortium Award (DOD). Since the PCCTC's inception in 2006, members have cooperatively designed, carried out, and evaluated phase 1 and 2 multicenter studies in prostate cancer. Methods: PCF and DOD awards support a consortium of 13 cancer research centers. Memorial Sloan-Kettering Cancer Center serves as the coordinating center and is charged with creating an infrastructure to conduct early phase, multicenter trials. Annually, each participating center is required to introduce at least one CT for consideration by the PCCTC and accrue at least 35 patients to PCCTC studies. Investigators meet face-to-face twice per year to discuss the PCCTC's progress, and hold monthly conference calls to discuss scientific objectives, trial design, and ongoing studies. Results: Since inception, the PCCTC has expanded from 8 to 13 leading research centers. Through September 2008, it has opened 47 trials and accrued 1,282 patients at member sites. Members utilize a CT management system for protocol tracking, electronic data capture, and data storage. A legal framework has been instituted, and standard operating procedures, administrative structure, editorial support, centralized budgeting, and mechanisms for scientific review have been established. Each year, the number of trials presented and patients accrued increases, and three concepts have progressed to the next phase of clinical testing. Conclusions: The PCCTC fulfills a congressional directive to create a CT instrument dedicated to rapid accrual to early-phase, multicenter studies in prostate cancer. The member institutions have built a shared administrative, informatics, legal, financial, statistical, and scientific infrastructure to support this endeavor. As the PCCTC has expanded and taken an increasingly active role in designing and evaluating protocols, clinical trials continue to open and accrue in excess of federally mandated goals.

No significant financial relationships to disclose.

Long term efficacy of peripheral androgen blockade on prostate cancer: CALGB 9782

4573

Background: The treatment of patients with a rising PSA after definitive local therapy is controversial. Patients are reluctant to undergo androgen suppression due to side effects and interest focuses on the timing and intensity of additional therapy. The use of peripheral androgen blockade in this setting is appealing. Methods: Patients with a rising PSA after definitive local therapy were enrolled in a multi-institutional trial. Accrual of 101 patients lasted from Sept 30, 1998 to July 16, 2001. All patients had undergone previous definitive local therapy at least 1 year, and no more than 10 years prior to enrollment. All patients had a repeated rising PSA, above 1 ng/ml, with no detectable evidence of recurrent disease. CT and bone scans were negative. Patients received a combination of oral therapy consisting of Finasteride, at a dose of 5 mg/day, and Flutamide, at a dose of 250 mg TID. Results: The median age was 71, with a median baseline testosterone level of 322 ng/dl. A >80% PSA decline was seen in 91/94, (97%) of the patients. Three other patients had PSA declines of 77%, 73% and 38%, all of which were maintained for at least 28 days. The median time to PSA nadir was 3.2 months. The current median follow-up is 59 months. To date, only 22 patients have progressed, with 47 patients still on peripheral androgen blockade. Eight patients have died without progression, and 22 patients went off therapy for other reasons not related to progression. Also noted were patients showing PSA responses to Flutamide withdrawal, and per protocol remaining on Finasteride. Toxicity to date remains very mild. Conclusions: Peripheral androgen blockade showed excellent activity produced durable PSA responses in this select group of patients. While the clinical significance of a decline in PSA alone is not fully understood_the durability of these PSA responses is encouraging. The median duration of progression free survival and overall survival has not been reached, and is likely to be longer than five years. Quality of life data is undergoing further analysis. This report supports further study of less aggressive treatments for patients who have only a rising PSA after definitive local therapy.

No significant financial relationships to disclose.

Randomized phase II study comparing 4 monthly doses of ipilimumab (MDX-010) as a single agent or in combination with a single dose of docetaxel in patients with hormone-refractory prostate cancer

4609

Background: Ipilimumab is a fully human anti-CTLA-4 IgG1 monoclonal antibody that blocks CTLA-4 and augments immune responses. The current study evaluated the safety and activity of ipilimumab alone or with a single dose of docetaxel in hormone-refractory prostate cancer (HRPC). Methods: 43 chemotherapy naïve patients (pts) with HRPC, were treated; 23 were in arm A (ipilimumab at 3 mg/kg q 4 weeks × 4 doses) and 20 in arm B (ipilimumab as in Arm A and one dose of 75 mg/m2 of docetaxel on day 1). Results: Six pts, 3 in each arm, demonstrated a decrease in PSA of > 50%. Three pts, 2 in arm A, and 1 in arm B had confirmed PSA responses with durations of 79+ days, 169+ days, and 280 days, respectively. There were no radiologic responses with these PSA responses. Thirty-six (84%) of the 43 pts experienced 1 or more adverse events considered to be related to treatment with ipilimumab. The most common adverse events included fatigue (44%), pruritus (26%), nausea (19%), rash (12%), constipation (12%), and weight loss (12%). Serious adverse events (SAEs) occurred in 18 patients (42%), who experienced 52 SAEs. The majority (42 out of 52, 81%) were judged by the Investigator to be unrelated or unlikely to be related to treatment with ipilimumab. Five of the 52 SAEs reported in 3 pts were considered to be possible immune breakthrough events (IBEs), associated with drug exposure and consistent with an immune-based mechanism of action. These were adrenal insufficiency (1), diarrhea, colitis, and melena (all in one patient) and colitis (1). One of these pts had a confirmed PSA response. Conclusions: Ipilimumab was well tolerated in this group of pts with HRPC. Three pts overall (6%) experienced an IBE, a phenomenon that has been correlated in other studies with efficacy. There were several confirmed responses as assessed by PSA, one of which was correlated with an IBE. There was no apparent enhancement of activity by coadministration of a single dose of docetaxel. Further studies exploring ipilimumab in prostate cancer are warranted, either as monotherapy at higher doses, or in combination with immune modulators or vaccines.

[Table: see text]

Outcome of patients with non-metastatic versus metastatic hormone refractory prostate cancer (HRPC) treated with second-line hormonal therapy consisting of ketoconazole (keto) plus granulocyte macrophage colony stimulating factor (GM-CSF)

4626

Background: Second line hormonal manipulations are frequently used in pts with HRPC. It is unknown if these manipulations are more effective in patients without clinical metastases. The efficacy of a second-line hormonal manipulation (keto plus GM-CSF) was prospectively evaluated in a cohort of HRPC patients with and without metastases. Methods: Eligible pts had progressive HRPC by consensus criteria, no prior immunotherapy, chemotherapy or keto. Pts received keto 400 mg po tid and hydrocortisone 20 mg po qAM and 10 mg po qPM. GM-CSF 250 mcg/m2 was administered SQ on days 15–28 of each 28-day cycle. Results: Forty-two of 48 planned pts have been enrolled, 30 with clinical metastases, 12 with PSA-only disease and are evaluable for PSA response, using consensus criteria. The median age is 68 years (range: 53–84), and median PSA 23.1 ng/mL (range: 5.4–306.5). The median treatment duration is 5.1 months (range: 0.3–22+). Overall, 30 of 43 patients (69%) have experienced a ≥ 50% reduction in PSA. The PSA response proportion in the non-metastatic patients is 8/12 (66%) while the response proportion in those with metastases is 16/30 (53%, chi squared p = 0.41). Twenty-three patients have discontinued therapy after a median of three cycles. Progressive disease has occurred in 17 patients, 3 of 12 patients with non-metastatic disease and in 14 of 30 patients with metastatic disease (25% vs. 47%, chi squared p=0.20). Six patients have discontinued due to toxicity or patient choice. The primary endpoint of the study, overall time to progression, has not been reached at a median follow up of 7 months. Conclusions: There was no significant difference in response proportion and progressive disease rate in HRPC patients with and without metastatic disease treated with keto/GM-CSF. While these data require prospective confirmation in a larger group of patients, they suggest that secondary hormonal manipulations are warranted in either patient group.

No significant financial relationships to disclose.

Biodiversity in urban habitat patches

We examined the biodiversity of urban habitats in Birmingham (England) using a combination of field surveys of plants and carabid beetles, genetic studies of four species of butterflies, modelling the anthropochorous nature of the floral communities and spatially explicit modelling of selected mammal species. The aim of the project was to: (i) understand the ecological characteristics of the biota of cities model, (ii) examine the effects of habitat fragment size and connectivity upon the ecological diversity and individual species distributions, (iii) predict biodiversity in cities, and (iv) analyse the extent to which the flora and fauna utilise the 'urban greenways' both as wildlife corridors and as habitats in their own right. The results suggest that cities provide habitats for rich and diverse range of plants and animals, which occur sometimes in unlikely recombinant communities. The studies on carabids and butterflies illustrated the relative importance of habitat quality on individual sites as opposed to site location within the conurbation. This suggests that dispersal for most of our urban species is not a limiting factor in population persistence, although elements of the woodland carabid fauna did appear to have some geographical structuring. Theoretical models suggested that dormice and water voles may depend on linear habitats for dispersal. The models also indicated that other groups, such as small and medium sized mammals, may use corridors, although field-based research did not provide any evidence to suggest that plants or invertebrates use urban greenways for dispersal. This finding indicates the importance of identifying a target species or group of species for urban greenways intended as dispersal routeways rather than as habitat in their own right. Their importance for most groups is rather that greenways provide a chain of different habitats permeating the urban environment. We suggest that planners can have a positive impact on urban biodiversity by slowing the pace of redevelopment and by not hurrying to tidy up and redevelop brownfield sites.

Kinetics of development and characteristics of antibodies induced in cancer patients against yeast expressed rDNA derived granulocyte macrophage colony stimulating factor (GM-CSF)

We have determined the presence and kinetics of granulocyte macrophage colony stimulating factor (GM-CSF) antibodies induced after repeated administration of a yeast expressed GM-CSF product in prostate cancer patients with minimal recurrent disease using a panel of assays for detection and characterization of antibodies. Results showed that all 15 prostate cancer patients treated with GM-CSF developed GM-CSF reactive antibodies during the course of therapy. Most patients (87%) developed GM-CSF reactive antibodies within 3 months while in other patients (13%), these antibodies were induced after additional cycles of GM-CSF treatment. For most patients, the timing of occurrence of these antibodies was the same regardless of whether the ELISA or surface plasmon resonance (SPR) assays were used for detection. However, in two patients, the recognition of GM-CSF reactive antibodies by SPR assays preceded their detection by ELISA. A significant number of patients (n=9, 60%) developed GM-CSF antibodies which neutralized the biological activity of GM-CSF in vitro in a cell-line based bioassay. These antibodies also recognized GM-CSF protein from different expression systems including the non-glycosylated protein from E. coli indicating that the antibody response is directed towards the amino acid backbone of the protein. A significant effect of GM-CSF antibodies on PSA modulation was not observed in this small cohort of patients despite an alteration in PSA levels in some treated patients. The study design used here did not allow conclusions regarding the relationship between neutralizing antibodies and the PSA levels which were used as a marker for clinical outcome. Implementation of a clinical strategy which permits monitoring for antibody development and for levels of a relevant pre-determined clinical marker at appropriate time-points is necessary for assessing the impact of antibody development on the therapeutic efficacy of the protein.

Transgenic crops : new weed problems for Canada?

Over 25 000 transgenic field trials were conducted globally from 1986-1997, and many transgenic crops, including soybean (Glycine max), maize (Zea mays), tobacco (Nicotiana tabaccum), cotton (Gossypium hirsutum), canola (Brassica napus, B. rapa), tomato (Lycopersicon esculentum) and potato (Solarium tuberosum) have been commercially released. There has been a high adoption rate, with at least 28 million ha reported for 1998, with herbicide- and insect-resistant plants occupying 71 and 28% of the releases, respectively. The current status of commercial production of transgenic crops in Canada is summarized. Transgenic crops have the potential to change weed communities/populations in three principal ways, via: 1 ) escape and proliferation of the transgenic plants as 'weedy' volunteers with subsequent displacement of the crop, weed and/or natural vegetation; 2) hybridization with and transgene infiltration into related weedy and/or wild species, resulting in invigorated weeds and/or alteration of natural gene frequencies in these species; and 3) genetic changes in populations of unrelated species, as a result of changes to the environment, in particular herbicide-resistant (HR) transgenic crops and the development of HR weeds. Potential risk can be estimated a priori using knowledge of the systematics of crop/wild/weed complexes. Risk must be assessed on a case-by-case basis for each crop, each country/ecological region, and for each trait. Potential weed risks will be greater if crop volunteers are predisposed to becoming weedy, are well adapted to the Canadian climate and if sexually compatible wild species are present.

Immunogenicity of GM-CSF products in cancer patients following immunostimulatory therapy with GM-CSF

There is a high risk of developing neutralising and non-neutralising antibodies when GM-CSF is used as an immunomodulatory agent in non-immunocompromised patients. The presence of neutralising antibodies may seriously hamper the clinical response of the patients. This must be taken into account when designing protocols if the biological activity of the exogenously administered GM-CSF is not to be impaired and the endogenous production of GM-CSF is not to be inactivated. Assessment of production of neutralising antibodies during cytokine therapy is important for predicting the clinical response to progressive therapy. Use of validated assays is imperative for evaluation of antibodies generated following therapy with a particular protein.

The new bisphosphonate, Zometa (zoledronic acid), decreases skeletal complications in both osteolytic and osteoblastic lesions: a comparison to pamidronate

Bisphosphonates are the treatment of choice for lytic bone lesions associated with breast cancer. In contrast, bone lesions associated with prostate cancer are predominately osteoblastic. Zoledonic acid (Zol) is a new-generation bisphosphonate that is approximately 2-3 orders of magnitude more potent than pamidronate (Pam) in preclinical models and has demonstrated clinical efficacy in patients with both lytic and blastic lesions. Zoledonic acid (4 mg via 15 min infusion) every 3-4 weeks was directly compared to Pam (90 mg via 2 hr infusion) in 767 patients with breast cancer and bone metastases. The primary endpoint was the proportion of patients experiencing a skeletal-related event (SRE) over 13 months. Zoledonic acid was as effective as Pam, and the proportion of Zol-treated patients with an SRE (42% in the hormonal therapy strata and 44% in the chemotherapy strata) was comparable to the original studies comparing Pam to placebo. Among 371 breast cancer patients receiving hormonal therapy, the proportion of patients with an SRE was 47% for Pam vs. 57% for placebo (P = 0.057), and among 380 patients treated with chemotherapy, the proportions with an SRE were 43% for Pam vs. 56% for placebo (P = 0.008) at 12 months. Zoledronic acid (4 mg) has been compared to placebo in a randomized Phase III trial involving 422 men with hormone-refractory prostate cancer metastatic to bone. Zoledonic acid demonstrated a significant advantage over placebo for median time to first SRE (median not reached for Zol vs. 321 days for placebo; P = 0.011), the proportion of patients with an SRE over 15 months (33 vs. 44% for placebo; P = 0.021), and mean skeletal morbidity rate (number of SREs/time, 0.08 vs. 1.49 for placebo; P = 0.006). In addition, the effects of Zol were apparent early. At 3 months, only 12% of Zol-treated patients had an SRE vs. 23% for placebo (P = 0.003), and at 6 months, the proportions were 21 vs. 31% for placebo (P = 0.025). In contrast, a previous study of Pam in 236 prostate cancer patients found that Pam was no more effective than placebo in reducing bone pain or SREs over 6 months. In these studies, Zol was well tolerated with a safety profile similar to other IV bisphosphonates. In conclusion, Zol is the first bisphosphonate to demonstrate efficacy in both lytic and blastic disease. The unique properties of this novel agent should be further explored in future clinical trials.

Dendritic cell-based treatment of cancer: closing in on a cellular therapy

PURPOSE

Dendritic cells are the most potent antigen-presenting cells and are critical to initiation of immune responses. Dendritic cells loaded ex vivo with tumor-associated antigen are being administered to cancer patients in an effort to jump-start a potent, cell-mediated anticancer immune response resulting in tumor shrinkage and clinical benefit.

PATIENTS AND METHODS

Dendreon Corporation has designed three therapeutic vaccines using blood-derived dendritic cells loaded ex vivo with antigen: Provenge for prostate cancer; Mylovenge for multiple myeloma and other B-cell malignancies; and APC8024 for cancers expressing the HER-2/neu proto-oncogene.

RESULTS

Preclinical studies demonstrated that blood dendritic cells matured spontaneously in short-term culture without growth factors, and that fusion of antigens with granulocyte-macrophage colony-stimulating factor enhances antigen uptake and presentation by blood dendritic cells. Phase I/II trials suggest that these dendritic cell-based vaccines are safe and well tolerated. Provenge has demonstrated antitumor activity in hormone-refractory prostate cancer; approximately 20% of patients experienced decreased prostate-specific antigen (i.e., PSA) levels and a similar percentage experienced disease stabilization. Double-blind, placebo-controlled, randomized trials in metastatic, asymptomatic hormone-refractory prostate cancer have been initiated. Phase II data on Mylovenge are similarly encouraging, and expanded phase II testing is ongoing in anticipation of opening phase III trials in 2002. APC8024 is in early clinical development and has shown significant capacity to elicit antigen-specific immune responses.

CONCLUSION

Antigen delivery by ex vivo antigen-loaded dendritic cells may be an effective approach to cancer immunotherapy.

Creatine use among young athletes

OBJECTIVE

Creatine is a nutritional supplement that is purported to be a safe ergogenic aid in adults. Although as many as 28% of collegiate athletes admit taking creatine, there is little information about creatine use or potential health risk in children and adolescents. Although the use of creatine is not recommended in people less than 18 years of age, numerous anecdotal reports indicate widespread use in young athletes. The purpose of this study was to determine the frequency, risk factors, and demographics of creatine use among middle and high school student athletes.

METHODS

Before their annual sports preparticipation physical examinations, middle and high school athletes aged 10 to 18 in Westchester County, a suburb north of New York City, were surveyed in a confidential manner. Information was collected regarding school grade, gender, specific sport participation, and creatine use.

RESULTS

Overall, 62 of 1103 participants (5.6%) admitted taking creatine. Creatine use was reported in every grade, from 6 to 12. Forty-four percent of grade 12 athletes surveyed reported using creatine. Creatine use was significantly more common (P <.001) among boys (53/604, 8.8%) than girls (9/492, 1.8%). Although creatine was taken by participants in every sport, use was significantly more common among football players, wrestlers, hockey players, gymnasts, and lacrosse players (P <.001 for all). The most common reasons cited for taking creatine were enhanced performance (74.2% of users) and improved appearance (61.3%), and the most common reason cited for not taking creatine was safety (45.7% of nonusers).

CONCLUSIONS

Despite current recommendations against use in adolescents less than 18 years old, creatine is being used by middle and high school athletes at all grade levels. The prevalence in grades 11 and 12 approaches levels reported among collegiate athletes. Until the safety of creatine can be established in adolescents, the use of this product should be discouraged.

Activation of cardiac gene expression by myocardin, a transcriptional cofactor for serum response factor

Serum response factor (SRF) regulates transcription of numerous muscle and growth factor-inducible genes. Because SRF is not muscle specific, it has been postulated to activate muscle genes by recruiting myogenic accessory factors. Using a bioinformatics-based screen for unknown cardiac-specific genes, we identified a novel and highly potent transcription factor, named myocardin, that is expressed in cardiac and smooth muscle cells. Myocardin belongs to the SAP domain family of nuclear proteins and activates cardiac muscle promoters by associating with SRF. Expression of a dominant negative mutant of myocardin in Xenopus embryos interferes with myocardial cell differentiation. Myocardin is the founding member of a class of muscle transcription factors and provides a mechanism whereby SRF can convey myogenic activity to cardiac muscle genes.

Strength training by children and adolescents

Pediatricians are often asked to give advice on the safety and efficacy of strength training programs for children and adolescents. This review, a revision of a previous American Academy of Pediatrics policy statement, defines relevant terminology and provides current information on risks and benefits of strength training for children and adolescents.

Organized sports for children and preadolescents

Participation in organized sports provides an opportunity for young people to increase their physical activity and develop physical and social skills. However, when the demands and expectations of organized sports exceed the maturation and readiness of the participant, the positive aspects of participation can be negated. The nature of parental or adult involvement can also influence the degree to which participation in organized sports is a positive experience for preadolescents. This updates a previous policy statement on athletics for preadolescents and incorporates guidelines for sports participation for preschool children. Recommendations are offered on how pediatricians can help determine a child's readiness to participate, how risks can be minimized, and how child-oriented goals can be maximized.

Focal therapy for prostate cancer 1996: maximizing outcome

OBJECTIVES

To summarize improvements in patient selection and the results of focal therapy for the management of localized prostate cancer.

METHODS

A contemporary series of patients managed with wide surgical excision, radiation therapy (three-dimensional conformal radiation, interstitial radiation, and charged-particle or proton therapy), and cryo-therapy were reviewed.

RESULTS

We used preoperative cancer grade, transrectal ultrasound, and serum prostate-specific antigen (PSA) in all patients, and cross-sectional imaging and bone scans in selected patients to allow for reasonably accurate cancer staging and selection of patients most likely to be cured by radical prostatectomy or radiation. In patients with extracapsular extension of prostate cancer, wide surgical excision and achievement of a clear surgical margin had therapeutic value. Newer radiation techniques resulted in a higher likelihood of prostate cancer control than previous techniques. Cryotherapy for patients with stages T1 through 3 prostate cancer was associated with a posttreatment undetectable PSA rate of 48% and a positive biopsy rate of 23%.

CONCLUSIONS

Patients with organ-confined and, therefore, curable prostate cancer can be identified. Well-performed radical prostatectomy, radiation, and cryotherapy are alternative treatments for the management of localized prostate cancer.

The young athlete with chronic disease

Iron deficiency anemia can affect athletic performance. Physicians must be wary of the at risk population, namely vegetarians, female adolescents, and long distance athletes. Particular attention must be paid to nutritional intake and to the use of nonsteroidal anti-inflammatory agents and aspirin.

Valuing the unseen emotional labour of nursing

This paper argues that comforting, listening, being reassuring and showing sympathy are important nursing skills that are vital to a patients' well-being and, as such, should be both valued and remunerated. The author also argues that the invisibility of these skills has been compounded by the NHS and Community Care Act 1990. This has meant that long-term care is being transferred into the hands of the private and voluntary sectors and informal carers. As an alternative to residential care, many social services departments now use the home care services of not-for-profit care agencies who employ 'ordinary' people to enable those needing long-term care to remain in their own home. Such workers are often paid in a way that does not remunerate the emotional element of their labour.