The legal threat to medicine.
Explore the source record for details and available documents.
Ethics, Medical↗
SEARCH · Search PubMed
Results for “R. v. Adams”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
A new caged Ca2+, azid-1, is far more photosensitive than nitrobenzyl-based chelators.
BACKGROUND: Photolabile chelators that release Ca2+ upon illumination have been used extensively to dissect the role of this important second messenger in cellular processes such as muscle contraction and synaptic transmission. The caged calcium chelators that are presently available are often limited by their inadequate changes in Ca2+ affinity, selectivity for Ca2+ over Mg2+ and sensitivity to light. As these chelators are all based on nitrobenzyl photochemistry, we explored the use of other photosensitive moieties to generate a new caged calcium with improved properties. RESULTS: Azid-1 is a novel caged calcium in which a fluorescent Ca2+ indicator, fura-2, has been modified with an azide substituent on the benzofuran 3-position. Azid-1 binds Ca2+ with a dissociation constant (Kd) of approximately 230 nM, which changes to 120 microM after photolysis with ultraviolet light (330-380 nm). Mg2+ binding is weak (8-9 mM Kd) before or after photolysis. Azid-1 photolyzes with unit quantum efficiency, making it 40-170-fold more sensitive to light than caged calciums used previously. The photolysis of azid-1 probably releases N2 to form a nitrenium ion that adds water to yield an amidoxime cation; the electron-withdrawing ability of the amidoxime cation reduces the chelator's Ca2+ affinity within at most 2 ms following a light flash. The ability of azid-1 to function as a caged calcium in living cells was demonstrated in cerebellar Purkinje cells, in which Ca2+ photolytically released from azid-1 could replace the normal depolarization-induced Ca2+ transient in triggering synaptic plasticity. CONCLUSIONS: Azid-1 promises to be a useful tool for generating highly controlled spatial and temporal increases of Ca2+ in studies of the many Ca2+-dependent biological processes. Unlike other caged calciums, azid-1 has a substantial cross section or shows a high susceptibility for two-photon photolysis, the only technique that confines the photochemistry to a focal spot that is localized in three dimensions. Azide photolysis could be a useful and more photosensitive alternative to nitrobenzyl photochemistry.
Animals↗
Gene expression profiling of fibroblasts resistant toward oncogene-mediated transformation reveals preferential transcription of negative growth regulators.
The signal-transducing Ras proteins are important driving forces of diverse cellular processes such as proliferation, neoplastic transformation, differentiation and growth inhibition. As a step toward understanding the complex mechanisms underlying cellular responses, gene expression patterns were examined in two phenotypically normal fibroblast lines which differ in their sensitivity toward oncogene-mediated transformation. Suppression subtractive hybridization (SSH) was used to establish a subtracted cDNA library specific for the REF52 cell line which, like normal diploid fibroblasts, is refractory toward neoplastic transformation induced by mutated HRAS oncogenes. In contrast, rat 208F control cells can be efficiently transformed by HRAS. The nucleotide sequence of 549 subtracted cDNA clones ('REF52 minus 208F') was determined. We identified 93 preferentially expressed gene fragments in resistant REF52 cells as compared to 208F cells. Seventeen of the 52 known genes (32.6%) are capable of inhibiting cell proliferation or of adversely affecting oncogenic signal transduction pathways. These results suggest that the anti-oncogenic properties of resistant REF52 cells are determined by multiple negative growth regulators. The preneoplastic state expressed in 208F cells is characterized by impairment of unexpectedly redundant control mechanisms. Our results also demonstrate that SSH is a powerful method for identifying specific transcriptional patterns in closely related cell types.
Cell Division↗
Normalised intrinsic mortality risk in liver transplantation: European Liver Transplant Registry study.
BACKGROUND: No model exists for liver transplantation to estimate the mortality risk in a given patient, and no standard by which to assess performance in different centres. We investigated the intrinsic mortality risk in the absence of known mortality risk factors. METHODS: We identified mortality risk factors and risk ratios quantified in data from the European Liver Transplant Registry (22,089 patients at 102 centres in 18 countries) registered from 1988 to 1997. To develop a model of the intrinsic risk and the risk ratios for specific factors, univariate and multivariate analyses were done separately for the overall population, for adults, and for children younger than 15 years, and the number of deaths were estimated. We validated the model by comparing mortality in patients without risk factors with the model-adjusted mortality in patients with risk factors. FINDINGS: Overall 5-year and 8-year actuarial survival was 66% (95% CI 65-66) and 61% (60-62). 65% of deaths occurred within 6 months. Retransplantation, transplantation for cancer, acute liver failure, fewer than 20 split-liver grafts per year, and a centre workload of fewer than 25 transplants per year were the main risk factors of 12 identified factors. 1-year and 5-year death rates among adults with no risk factors were similar to model estimates (15 [13-16] vs 14% [13-15], and 22 (20-24) vs 23% [21-24]). Corresponding data for paediatric transplants were 9% (7-12) compared with 11% (9-12) and 13% (10-17) compared with 14% (11-16). The reduction of mortality risk in high-volume centres was even greater in patients without risk factors (48 vs 23%, p<0.001). INTERPRETATION: The normalised intrinsic mortality risk can be combined with the relative risk ratios of known risk factors to better estimate the mortality risk of a given procedure in a given patient. Centres can assess performance by removing potential bias of donor and recipient selection.
Adolescent↗
The use of transcranial ultrasonography to predict stroke in sickle cell disease.
BACKGROUND: Stroke, especially cerebral infarction, is a major cause of morbidity and mortality in children with sickle cell disease. Primary prevention of stroke by transfusion therapy may be feasible if there is a way to identify the patients at greatest risk. Transcranial Doppler ultrasonography can measure flow velocity in the large intracranial arteries. The narrowing of these arteries, which leads to cerebral infarction, is characterized by an increased velocity of flow. METHODS: Using transcranial Doppler ultrasonography, we prospectively measured the velocity of cerebral blood flow in children and young adults being followed because of sickle cell disease. The results were classified as either normal or abnormal on the basis of the highest velocity of flow in the middle cerebral artery. Abnormal velocity was defined as a flow greater than or equal to 170 cm per second, a definition determined by post hoc analysis to maximize the predictive success of the test. The end point was a clinically apparent first cerebral infarction. RESULTS: Two hundred eighty-three transcranial ultrasound examinations were performed in 190 patients with sickle cell disease (age at entry, 3 to 18 years). After an average follow-up of 29 months, cerebral infarction was diagnosed in seven patients. In 23 patients the results of the ultrasound examinations were abnormal, and in 167 patients they were normal. The clinical and hematologic characteristics of the two groups were similar, but six of the seven strokes occurred among the 23 patients with abnormal ultrasound results (P less than 0.00001 by Fisher's exact test). In this group, the relative risk of stroke was 44 (95 percent confidence interval, 5.5 to 346). CONCLUSIONS: Transcranial ultrasonography can identify the children with sickle cell disease who are at highest risk for cerebral infarction. Periodic ultrasound examinations and the selective use of transfusion therapy could make the primary prevention of stroke an achievable goal.
Adolescent↗
Morphology and ultrastructure of the digestive gland of Bithynia siamensis goniomphalus (Prosobranchia: Bithyniidae) and alterations induced by infection with the liver fluke Opisthorchis viverrini (Trematoda: Digenea).
The morphology and ultrastructure of the digestive gland of Bithynia siamensis goniomphalus and its alteration by infection with Opisthorchis viverrini were investigated by light and electron microscopy. The digestive gland of B. s. goniomphalus was composed of three different cell types: digestive cells, excretory cells, and narrow cells. In infected animals the number of excretory cells increased dramatically. Cellular injury in digestive cells as well as in excretory cells following the infection could be observed at the ultrastructural level.
Animals↗
An assessment of emergency medicine residency graduates' perceptions of the adequacy of their residency training.
A study of emergency medicine residency training graduates was conducted to determine their perceptions of the quality of their graduate training. A sample of 300 individuals was randomly selected from a population of 1,000 persons graduating from 1982 through 1984. Respondents were asked to use a scale of 1 to 5 (with 1 being highest) to rate the adequacy of their residency training relative to 20 major core content areas. A 50% response rate (N = 151) was achieved. Mean ratings of residents' perceptions of the adequacy of their training relative to the core content ranged from 1.7 to 3.24. Training in resuscitation and stabilization, principles of emergency care, and general assessment were among the most highly rated, while training in physician interpersonal skills, disorders related to the immune system, and cutaneous disorders were rated the lowest. Overall, residents were quite positive in their perceptions regarding the quality of their training. They indicated plans to attend continuing medical education programs to reinforce some of their training and to address some of the deficiencies they perceived in residency training. Programs are encouraged to conduct similar surveys with their own graduates to assess particular strengths and weaknesses.
Adult↗
Oprelvekin (Neumega), first platelet growth factor for thrombocytopenia.
Oprelvekin decreases the need for platelet transfusion in nontransplant patients receiving myelosuppressive chemotherapy. Until pharmacoeconomics studies determine the most cost-effective strategy for use of oprelvekin, it is likely to be used primarily in patients receiving dose-intensive chemotherapy to maintain the high-dose regimen that may provide a survival advantage for the patient with cancer. Additional product information is available at www.ahp.com/products/neumega.htm.
Antineoplastic Agents↗
Antiangiogenesis agents in clinical trials.
Explore the source record for details and available documents.
Angiogenesis Inhibitors↗
Unusual temperature-dependent diastereoselectivity in the [2 + 2] photocycloaddition (Paternò-Büchi reaction) of benzophenone to cis- and trans-cyclooctene through conformational control.
Explore the source record for details and available documents.
Benzophenones↗
Teenagers and alcohol misuse in the United States: by any definition, it's a big problem.
Despite the fact that more adolescents use alcohol than any other drug, studies of teenage alcohol misuse are relatively rare. Those that exist frequently fail to include high school dropouts and often focus on only part of the problem, such as how much or how often the adolescent drinks. This study examines the prevalence and demographic predictors of teenage alcohol misuse in a diverse sample of 4390 high school seniors and dropouts. It focuses on three different dimensions of misuse--high-risk drinking, alcohol-related problems and high consumption--and provides prevalence estimates by gender and race/ethnicity that are weighted to represent the original seventh grade cohort of 30 California and Oregon schools. Results show that by grade 12, nearly 70% of these teenagers have exhibited some form of alcohol misuse within the past year. Two-thirds have engaged in high-risk drinking and over 50% have experienced one or more alcohol-related problems. More stringent estimates that require variety or persistence of risky drinking and/or alcohol-related problems still capture between 40% and 54% of this population. However, focusing solely on high consumption fails to identify as many as half of these at-risk misusers. Males and females both exhibit high rates of alcohol misuse, as do most racial ethnic groups. However, African Americans and Asians are less likely to misuse alcohol than whites and Hispanics. The results underscore the need for including different forms of alcohol misuse in prevention programs, for improving our understanding of its etiology, and for providing upper and lower bound estimates of alcohol misuse in future research.
Adolescent↗
Use of echo planar imaging to demonstrate the effect of posture on the intragastric distribution and emptying of an oil/water meal.
Intragastric distribution of solids and liquids is far from uniform but until recently technical limitations have prevented detailed study. Echo planar imaging (EPI), which can provide high-quality images of intragastric contents, has been used in this study to assess the intragastric distribution of oil and water and gastric emptying in subjects lying on either their left or right side. Eight healthy volunteers underwent four gastric emptying studies after consuming either an aqueous meal (400 mL beef consomme soup + 100 mL water) or a fat/aqueous meal (400 mL soup + 100 mL olive oil) lying on either their left or right side. Using a water suppressed imaging mode the lipid phase was clearly seen layering above the aqueous phase with little evidence of mixing. Gastric emptying of the aqueous meal (A) was not significantly different when lying on the left compared to the right side. However, gastric emptying of the aqueous phase of the fat/aqueous meal (B) was considerably slower when lying on the left compared to the right side, gastric volumes actually increasing over the 90 min of the study P < or = 0.05. When lying on the right side the aqueous phase of meal B emptied significantly slower than meal A. Oil was clearly observed to layer above the water and fill the duodenal cap when subjects lay on their left and the fundus when they lay on their right side. EPI clearly demonstrates the intragastric layering of oil which causes posture to strongly influence gastric emptying. EPI is a tool with great potential to describe the intragastric events following ingestion of complex multiphase meals.
Adult↗
Modern Diagnostic Methods in Ewing's Sarcoma Family: Six Patients With Histologic Soft Tissue Tumors.
Background: Soft tissue tumors often present a major diagnostic challenge for the pathologist. The correct diagnosis has important prognostic and therapeutic consequences. In recent years significant progress has been made in identifying characteristic chromosomal abnormalities associated with certain solid tumors. More than 85% of tumors in the Ewing's sarcoma (ES) family contain a specific t(11;22) (q24;q12) translocation. Methods and Results: We present six patients with a soft tissue tumor of which only four were diagnosed primarily as belonging to the ES family. All cases were further examined by the following methods: immunohistochemistry with MIC2, cytogenetics, nested reverse transcription-polymerase chain reaction of the t(11;22), using fresh-frozen or formalin-fixed, paraffin-embedded archival material. Conclusions: This method clearly allowed the diagnosis of a tumor of the ES family in all six cases.
Journal Article↗
Resection of nonresectable liver metastases from colorectal cancer after percutaneous portal vein embolization.
OBJECTIVE: To assess the influence of preoperative portal vein embolization (PVE) on the long-term outcome of liver resection for colorectal metastases. SUMMARY BACKGROUND DATA: Preoperative PVE of the liver induces hypertrophy of the remnant liver and increases the safety of hepatectomy. METHODS: Thirty patients underwent preoperative PVE and 88 patients did not before resection of four or more liver segments. PVE was performed when the estimated rate of remnant functional liver parenchyma (ERRFLP) assessed by CT scan volumetry was less than 40%. RESULTS: PVE was feasible in all patients. There were no deaths. The complication rate was 3%. The post-PVE ERRFLP was significantly increased compared with the pre-PVE value. Liver resection was performed after PVE in 19 patients (63%), with surgical death and complication rates of 4% and 7% respectively. PVE increased the number of resections of more than four segments by 19% (17/88). Actuarial survival rates after hepatectomy with or without previous PVE were comparable: 81%, 67%, and 40% versus 88%, 61%, and 38% at 1, 3, and 5 years respectively. CONCLUSIONS: PVE allows more patients with previously unresectable liver tumors to benefit from resection. Long-term survival is comparable to that after resection without PVE.
Aged↗
Virilization during pregnancy with spontaneous resolution postpartum: a case report and review of the English literature.
The incidence of gestational hyperandrogenism secondary to ovarian pathology is low. However, when the condition does exist, diagnosis should be made with minimally invasive modalities. It is important to provide appropriate medical/surgical intervention without disturbing the pregnancy iatrogenically or causing unnecessary maternal morbidity. This case report adds to the existing radiographic data concerning this rare obstetrical condition. Presented is a review of the English literature on virilizing ovarian tumors during pregnancy, and a discussion of an approach to managing these tumors when they occur during pregnancy.
Adult↗
Delayed graft function after renal transplantation.
BACKGROUND: There is a strong association between delayed graft function (DGF) and reduced graft survival (GS) of cadaveric renal transplants. This study was performed to identify donor characteristics that might predict adverse outcomes. METHODS: We reviewed the folders of 509 consecutive organ donors for 586 renal transplant recipients receiving grafts between 1990 and 1995. A uniform immunosuppression protocol was employed. RESULTS: The factors that did not alter the rate of DGF were procurement year, local versus shared organs, donor gender, race, hypotension, serum creatinine level and trend, blood transfusions, and vasopressor use and dose. The factors that did alter the frequency of DGF were cause of death (P=0.0053), donor age (P=0.0017), cold ischemic time (P=0.0009), anastomotic time (P=0.0012), combined cold ischemic time and anastomotic time (P=0.00018), and body mass index (P=0.009). All of the factors with the exception of body mass index were of comparable import when analyzed by multiple logistic regression. One-year GS of patients without DGF was 93.2%, and the GS of those with DGF was 76.6% (P < 0.0001). However, none of the donor factors correlated with 1-year GS. Seventy-seven donors were the source of paired transplants performed by our program. Sixty percent were concordant for immediate function, 32% were discordant for DGF with equal numbers affecting the first or second graft, and in only 8% did DGF affect both grafts. CONCLUSIONS: Donor factors associated with DGF were increased ischemia, donor age, and cause of death. Although there is a close association between DGF and reduced GS, there is no association between these donor factors and GS. This seeming paradox suggests that unknown variables contribute heavily to early graft outcome.
Adolescent↗
Vomiting in paracetamol poisoning.
Explore the source record for details and available documents.
Acetaminophen↗