Stream terraces of the Salt River form the interpretive backbone of Plio-Pleistocene landscape evolution of central Arizona, because they represent the base level of all tributary streams. This paper ...presents a new addition to T.L. Péwé' s Salt River Terrace sequence (in decreasing topographic position and age: Sawik, Mesa, Blue Point, and Lehi) that has been unrefined for the last 30 years. The existence of an older, higher terrace was predicted by research suggesting that the lower Salt River originated by lake overflow from an ancestral Pliocene lake in the Tonto Basin. Field reconnaissance, aerial photo interpretation, and sedimentological analysis revealed this terrace on the north side of the Salt River, named here the Stewart Mountain Terrace (SMT). Where exposed, the fluvial sediments of SMT overlay Tertiary basin fill unconformably. SMT sediments are characterized by ∼50 m thick fluvial gravels found more than 70 m above remnants of the Sawik Terrace. Although the gravels are distinctly Salt River in origin, Stewart Mountain gravels differ from the lower and younger Salt River Terraces. The clast sizes are much larger on average and host a significantly different lithology. Because of these differences the SMT has profound implications for the understanding of regional drainage reorganization after basin and range extension. The existence of this terrace and its distinct gravels are consistent with, but do not prove, a lake overflow mechanism for the initiation of through flowing drainage in the Salt River Valley.
Purpose: This study was designed to evaluate a combined modality treatment for malignant gliomas using radiation therapy with a radiosensitizer and an adjuvant chemotherapy regimen designed to modify ...resistance to BNCU.
Methods and Materials: Patients were eligible if they were 15 years of age or older, and had newly diagnosed glioblastoma multiforme (GBM), or anaplastic glioma (AG). Treatment consisted of external beam radiotherapy given to a dose of 60 Gy using a single daily fraction Monday to Friday. Concurrent hydroxyurea at a dose of 300 mg/m
2 every 6 h every other day was given during radiation. Following radiotherapy, patients were then treated with BCNU and 6-Thioguanine (6TG). The 6-TG was given by mouth every 6 h for 12 doses prior to BCNU. Patients were initially treated with 60 mg/m
2/dose of 6TG, with escalation to a maximum dose of 100 mg/m
2/dose. The primary study end points were time to tumor progression and survival.
Results: A total of 245 eligible patients were enrolled from 1/18/88 to 12/26/91. The histologic subtypes included 135 GBM, and 110 with AG (103 with anaplastic astrocytoma, 7 with high-grade mixed oligoastrocytoma). For the GBM group, the median time to tumor progression (TTP) and median survival were 33 (95% CI 26, 39) and 56 (95% CI 49, 69) weeks, respectively. For the AG group the median TTP was 282 weeks (95% lower confidence bound = 155 weeks). Median survival for this group has not been reached (95% lower confidence bound = 284 weeks) with a median follow-up for surviving patients of 298 weeks. A proportional hazards model was used to look at potential prognostic factors for survival, including initial Karnofsky Performance Scale (KPS), age, and extent of surgery, as well as dose of 6TG. Higher KPS, and lower age, predicted for longer survival (
p
< 0.01, < 0.001) in GBM patients; lower age was significant (
p
= 0.05) for AG cases. A higher (greater than 95 mg/m
2) or lower dose of 6TG was not statistically significant in this model.
Conclusions: This therapy was no more effective in patients with GBM than other reported series. In patients with malignant gliomas other than GBM, prolonged progression-free and overall survival is noted, without a median survival reached at the time of this report. In this subset of AG patients, survival is comparable to recent studies using halogenated prymidines during radiation and Procarbazine, CCNU, and Vincristine (PCV) as adjuvant chemotherapy.
The utility of three-dimensional (3-D) proton magnetic resonance spectroscopy (1H-MRS) imaging for detecting metabolic changes after brain tumor therapy was assessed in a serial study of 58 total ...examinations of 12 patients with glioblastoma multiforme (GBM) who received brachytherapy. Individual proton spectra from the 3-D array of spectra encompassing the lesion showed dramatic differences in spectral patterns indicative of radiation necrosis, recurrent or residual tumor, or normal brain. The 1H-MRS imaging data demonstrated significant differences between suspected residual or recurrent tumor and contrast-enhancing radiation-induced necrosis. Regions of abnormally high choline (Cho) levels, consistent with viable tumor, were detected beyond the regions of contrast enhancement for all 12 gliomas. Changes in the serial 1H-MRS imaging data were observed, reflecting an altered metabolism following treatment. These changes included the significant reduction in Cho levels after therapy, indicating the transformation of tumor to necrotic tissue. For patients who demonstrated subsequent clinical progression, an increase in Cho levels was observed in regions that previously appeared either normal or necrotic. Several patients showed regional variations in response to brachytherapy as evaluated by 1H-MRS imaging. This study demonstrates the potential of noninvasive 3-D 1H-MRS imaging to discriminate between the formation of contrast-enhancing radiation necrosis and residual or recurrent tumor following brachytherapy. This modality may also allow better definition of tumor extent prior to brachytherapy by detecting the presence of abnormnal metabolite levels in nonenhancing regions of solid tumor.
Between February 1984 and September 1990, 60 patients with brainstem gliomas were treated with hyperfractionated radiotherapy in the Department of Radiation Oncology at the University of California, ...San Francisco. Forty-one children (< or = 18 years) and 19 adults were treated with 100 cGy twice daily with 4-8 hr between doses. Thirty-one patients (21 children and 10 adults) received total doses of 66-72 Gy and 29 patients (20 children and nine adults) received 74-78 Gy. Median follow-up was 208 weeks for all patients (214 weeks for children, 157 weeks for adults). Twenty-three patients (14 children and nine adults) were alive at the time of analysis, surviving 59-359 weeks following treatment. Median actuarial survival was 73.6 weeks overall (72 weeks for children, 190 weeks for adults; p = 0.43). Survival at 12 and 24 months was 65% and 38%, respectively (63% and 32%, for children; 68% and 53% for adults). All patients had pretreatment magnetic resonance imaging by which tumors were classified as either focal or diffuse. No significant pretreatment prognostic factors for adults were identified. In children, significant favorable prognostic factors on univariate analysis were older age (p = 0.001), tumor location in thalamus or midbrain (p = 0.002), focal appearance on MRI scan (p < 0.001) and duration of symptoms > 2 months prior to treatment (p < 0.001). Thirty-five patients had tumor biopsies, leading to a diagnosis in 33 (22 children and 11 adults). Children with moderately anaplastic astrocytomas survived significantly longer than those with glioblastoma multiforme or unbiopsied tumors (p < 0.001). Only duration of symptoms > 2 months remained significant as a favorable prognostic indicator for children on multivariate analysis (p < 0.001). Survival was not significantly different for patients receiving < or = 72 Gy and those receiving > 72 Gy (p = 0.18). No subgroup of patients showed significantly better survival with the higher dose. These findings indicate that hyperfractionated radiotherapy is effective treatment for adults and a subgroup of better prognosis children with brainstem gliomas. There is a subgroup of pediatric patients with extremely poor prognosis for whom even this aggressive treatment does little to extend survival. We conclude that there is no benefit to increasing total dose above 72 Gy for any of the groups analyzed.
Diluted ram sperm can be held for 24h at 5 degrees C prior to cryopreservation without impacting cryosurvival rates, however, the effects this storage has on subsequent fertility are unknown. These ...studies were conducted to evaluate the fertility of semen held for 24h (to mimic shipping semen to a cryopreservation center), prior to freezing. Semen from Suffolk rams (n=3 in experiment 1 and n=6 in experiment 2) with initial motility of greater than 70%, were diluted to 200 x 10(6)sperm/mL, in one step, with a Tris-egg yolk-glycerol diluent. In experiment 1, diluted samples were cooled to 5 degrees C over 2h, and then divided. Sperm in one fraction were loaded into 0.5mL straws, frozen (T0) and stored in liquid nitrogen until thawing. Sperm in the second fraction were held at 5 degrees C for 24h (T24) before being frozen. In experiment 2 ejaculates were collected and divided into two fractions. Sperm in one fraction were treated with cholesterol-loaded cyclodextrin (CLC) and sperm in the other served as control. Both fractions were diluted, cooled, and cryopreserved as described in experiment 1. Stage of the estrous cycle was synchronized in ewes (n=196) using controlled internal drug releasing devices (CIDR) for 12d and at CIDR removal each ewe was administered PMSG (500IU in experiment 1 and 350IU in experiment 2) immediately before insemination. Ewes were stratified by age and randomly assigned to one of the semen treatments; experiment 1: Fresh (F), T0, or T24; experiment 2: F, T24, or CLC, and inseminated laparoscopically 56h after CIDR removal. Differences in fertility were detected between experiments, but not for treatments within experiments. Differences in fertility were also observed due to ewe age, with the 3-year-old ewes having the greatest fertility (50.7%) and 6-year-old ewes having the least fertility (9.6%; P<0.05). Differences in the prolificacy rates due to semen treatment were also observed but differences due to ewe age were not detected. Therefore, sperm can be held at 5 degrees C for 24h prior to cryopreservation without altering sperm fertility.
Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests ...in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29 years among regions. Increases were also pervasive across elevations, tree sizes, dominant genera, and past fire histories. Forest density and basal area declined slightly, which suggests that increasing mortality was not caused by endogenous increases in competition. Because mortality increased in small trees, the overall increase in mortality rates cannot be attributed solely to aging of large trees. Regional warming and consequent increases in water deficits are likely contributors to the increases in tree mortality rates.
The lack of reliable, noninvasive methods to diagnose early nonalcoholic steatohepatitis (NASH) is a major unmet need. We aimed to determine the diagnostic accuracy of three‐dimensional magnetic ...resonance elastography (3D‐MRE), with shear stiffness measured at 60 Hz, damping ratio at 40 Hz, and magnetic resonance imaging proton density fat fraction (MRI‐PDFF) in the detection of NASH in individuals undergoing bariatric surgery. Obese adults at risk for NASH were enrolled between 2015 and 2017 (prospective cohort, n = 88) and 2010 and 2013 (retrospective cohort, n = 87). The imaging protocol consisted of multifrequency 3D‐MRE (mf3D‐MRE) with shear waves delivered at different frequencies to explore parameters that best correlated with histologic NASH, and MRI‐PDFF to estimate steatosis. The prospective cohort was used to establish the optimal mf3D‐MRE technical parameters for NASH detection. The two cohorts were then combined to derive predictive models of NASH and disease activity by nonalcoholic fatty liver disease activity score (NAS) using the three imaging parameters that correlated with NASH. A total of 175 patients (median age 45, 81% women, and 81 46% with histologic NASH) were used for model derivation. From the complex shear modulus output generated by mf3D‐MRE, the damping ratio at 40 Hz and shear stiffness at 60 Hz best correlated with NASH. The fat fraction obtained from MRI‐PDFF correlated with steatosis (P < 0.05 for all). These three parameters were fit into a logistic regression model that predicted NASH with cross‐validated area under the receiver operating characteristic curve (AUROC) = 0.73, sensitivity = 0.67, specificity = 0.80, positive predictive value = 0.73 and negative predictive value = 0.74, and disease activity by NAS with cross‐validated AUROC = 0.82. Conclusion: The mf3D‐MRE allows identification of imaging parameters that predict early NASH and disease activity. This imaging biomarker represents a promising alternative to liver biopsy for NASH diagnosis and monitoring. The results provide motivation for further studies in nonbariatric cohorts.
Reviews Fitz, Brewster; Child, Brenda J.; Weaver, Laura Adams ...
American Indian culture and research journal,
01/2007, Letnik:
31, Številka:
3
Journal Article
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