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Biomedical subjects

J Pederson

Publications and source records attributed to J Pederson.

18 recordsLinked to original sources
PubMed2001

Gulfwatch: monitoring spatial and temporal patterns of trace metal and organic contaminants in the Gulf of Maine (1991-1997) with the blue mussel, Mytilus edulis L.

Gulfwatch, established in 1991, is an international contaminant monitoring program in which the blue mussel, Mytilus edulis, is used as an indicator of the level and extent of contamination in the Gulf of Maine. Since 1991, trace metals, PAHs, PCBs, and OC pesticides have been measured in mussel tissues at 56 sites. The distribution of most metals was relatively uniform throughout the Gulf with the exception of Ag, Pb and Cr. However, the concentration of organic contaminants increased in a north-to-south direction. High concentrations of contaminants were correlated with large human population density and proximity to large rivers. Temporal analysis of five sites revealed that the majority of contaminant concentrations were either unchanged or decreasing. The concentrations of most contaminants were lower than the median of the National Status and Trends (NS & T) Mussel Watch with the exceptions of Cr, Hg, Pb and sigma PCB24. Hg concentrations at > 80% of the Gulfwatch sites exceeded the NS & T median +1 SD. Gulfwatch continues as a primary contaminant monitoring program in the Gulf of Maine.

Animals↗
PubMed1998

Chromosome 2 sequence of the human malaria parasite Plasmodium falciparum.

Chromosome 2 of Plasmodium falciparum was sequenced; this sequence contains 947,103 base pairs and encodes 210 predicted genes. In comparison with the Saccharomyces cerevisiae genome, chromosome 2 has a lower gene density, introns are more frequent, and proteins are markedly enriched in nonglobular domains. A family of surface proteins, rifins, that may play a role in antigenic variation was identified. The complete sequencing of chromosome 2 has shown that sequencing of the A+T-rich P. falciparum genome is technically feasible.

Amino Acid Sequence↗
PubMed1997

Gonioscopic evaluation of haptic position in transsclerally sutured posterior chamber lenses.

PURPOSE: To determine the haptic position in transsclerally sutured posterior chamber lenses. METHODS: Fifty eyes with transsclerally sutured posterior chamber lenses were evaluated gonioscopically to determine the superior haptic position using previous peripheral iridectomies. RESULTS: The superior haptic of the transsclerally sutured posterior chamber lens was visualized in 31 (62%) of the eyes. In 24 (77%) of the 31 eyes, the haptic was within the ciliary sulcus, and in seven (23%), it was located posterior to the sulcus. A fibrotic membrane was detected around the sutured haptic in 20 (83%) of the 24 lenses located within the sulcus, whereas no fibrosis was seen surrounding the seven haptics outside the sulcus (P < .0001). CONCLUSIONS: Proper positioning of the haptics may be correlated with the development of fibrosis surrounding the haptic and therefore may be an important factor in the long-term stability of transsclerally sutured posterior chamber lenses.

Gonioscopy↗
PubMed1993

Interruptions of high-dose radiation therapy decrease long-term survival of favorable patients with unresectable non-small cell carcinoma of the lung: analysis of 1244 cases from 3 Radiation Therapy Oncology Group (RTOG) trials.

PURPOSE: To determine if prolonged treatment time adversely affects survival for patients with inoperable non-small cell carcinoma of the lung. METHODS AND MATERIALS: Patients enrolled on three randomized studies (RTOG 8311, 8321, 8403) between 1983-1989 formed the database. Previous analyses found that the addition of thymosin (8321) or prophylactic cranial irradiation (8403) failed to prolong survival: both studies used thoracic irradiation with standard fractionation to 55-60 Gy in 30 fractions. In 8311, patients were treated by hyperfractionated radiation therapy to randomly assigned total doses of 60.0 Gy, 64.8 Gy, 69.6 Gy, 74.4 Gy or 79.2 Gy, 1.2 Gy twice daily, 5 days per week. Patients analyzed received +/- 4% of the assigned total dose and lived > 90 days (to ensure that all patients would have completed treatment). Completion < 5 days beyond protocol specifications was classified as "per protocol." Elapsed treatment time exceeding specifications by 5-9 days was a minor deviation, 10-13 days was a major deviation-acceptable, and > or = 14 days was a major deviation-unacceptable. Absolute survival was the endpoint to evaluate the effect of delays. The log rank statistic was used to test for survival differences in the univariate setting, the Cox regression model was used in the multivariate setting. RESULTS: Of 293 patients treated with standard fractionation, eight (2.7%) had deviations from the specified treatment time (six minor, two major-acceptable). With hyperfractionation, 90 (15%) patients had deviations (40 minor, 21 major-acceptable, 29 major-unacceptable). As the assigned dose increased, the deviation rate increased (9.7% for 60.0 Gy vs. 20.8% for 79.2 Gy). Survivals for hyperfractionation patients with any deviations in treatment time were significantly shorter than those treated "per protocol" (p = 0.16): estimated 2- and 5-years rates were 24% and 10% versus 13% and 3%, respectively. Multivariate analyses showed the delay effect to be entirely in patients treated with 69.6 Gy or higher; there was also dependence upon the patients' prognosis. In patients with favorable prognosis (KPS 90-100, weight loss < or = 5%, no N3), the difference in survival was pronounced (33% and 15% vs. 14% and 0% at 2- and 5-years, respectively). Such differences were not found in patients with unfavorable prognostic factors. CONCLUSIONS: Interruptions delaying completion of planned radiation therapy were more frequent with higher total doses (> or = 69.6 Gy). Favorable patients (high KPS, little weight loss, < N3 nodal metastasis) had markedly adverse effects on long-term survival associated with delays to completion of the planned total dose.

Adult↗
PubMed1992

High-dose local irradiation plus prophylactic hepatic irradiation and chemotherapy for inoperable adenocarcinoma of the pancreas. A preliminary report of a multi-institutional trial (Radiation Therapy Oncology Group Protocol 8801).

Adenocarcinoma of the pancreas is an extremely malignant neoplasm with a particular propensity to spread to the liver. In an effort to combine chemotherapy with high-dose local irradiation plus a modest dose of irradiation to suspected (subclinical) hepatic metastasis, patients with unresectable pancreatic carcinomas with no known distant metastasis were treated on a prospective multi-institutional Radiation Therapy Oncology Group (RTOG) Phase I/II trial. High total dose continuous radiation therapy to the pancreas (6120 cGy in 34 fractions over 7 weeks) and simultaneous prophylactic hepatic irradiation (PHI, 2340 cGy in 13 fractions for the last 2.5 weeks) were combined with administration of 5-fluorouracil 1000 mg/m2/day (maximum, 1500 mg) by intravenous continuous infusion for 5 days starting on day 1 and repeated on day 30 for 5 days, followed by a dose of 600 mg/m2 as a weekly bolus injection starting during week 9 for 6 months. In 18 months, 81 patients were enrolled in the study; 79 were evaluable with a minimum potential follow-up of 8.2 months. The patients ranged in age from 32 to 75 years (median, 64 years). Karnofsky performance status was 80 to 100 in 74% of patients. The tumor was confined to the head of the pancreas in 72% of patients. The planned radiation therapy for the pancreas was completed in 87% of patients, 80% received the planned PHI, and 85% completed the first two cycles of chemotherapy. Seventy-five percent of patients completed both treatments according to the protocol. Most patients who did not complete both treatments had tumor progression or refused additional therapy. During all cycles of chemotherapy and radiation therapy, 2 patients died of complications (Grade 5, 1 hepatic and 1 infection), 9 had life-threatening reactions (Grade 4, 7 hematologic, 1 neurologic, and 1 mucositis), and 31 patients had severe effects (Grade 3) according to the RTOG toxicity scale. Overall hepatic metastasis was documented in 32% (13% as the first site of failure), persistent or progressive pancreatic tumor was evident in 73%, and abdominal and extra-abdominal spread were reported in 27% and 8% of patients, respectively. Eighty percent (63 patients) died (median survival, 8.4 months). Although this study suggests that PHI may reduce the frequency of hepatic metastasis, failure to control the primary tumor and intraabdominal spread remain overwhelming.

Adenocarcinoma↗
PubMed1987

Family management in the prevention of morbidity of schizophrenia: social outcome of a two-year longitudinal study.

Effective community treatment of schizophrenia involves not merely the removal of florid symptoms, but restoration of effective social role functioning. The efficacy of a family management approach is compared with an individual approach of similar intensity in terms of its impact on the patient's social adjustment after a florid episode of schizophrenia. Clinical reports, patient self-reports, and interviews with the family members of 36 patients, who were randomly assigned to family or individual management, demonstrated a consistent superiority for family management. The advantages for the family approach were sustained over a two-year period. The potential mechanisms through which the family approach may have achieved its greater efficacy are discussed from a multi-determined perspective.

Adolescent↗
PubMed1987

Protein synthesis, cellular amino acids, and energy levels in CAPD patients.

Cellular energy-related bioactivities [energy charge = ATP + 0.5 ADP/(ATP + ADP + AMP)], enzyme activities adenylate kinase, pyruvate kinase, phosphofructokinase, glucose-6-phosphate dehydrogenase, free amino acids in plasma and cells, and protein synthesis (3H-leucine incorporation) were measured in granulocytes isolated from peripheral blood of 13 CAPD-treated adult patients. The values were compared with 37 normal adult controls, 29 of whom had complete data for all biochemical parameters. Eleven of the CAPD patients were studied a second time, 3 to 8 months after the first study. Initially, after 20 +/- 8 months of CAPD compared (P less than 0.05, only) to controls, the patients had normal or increased activities of the enzymes pyruvate kinase, phosphofructokinase, glucose-6-phosphate dehydrogenase, in contrast to previous results from hemodialyzed patients; but adenylate kinase, ATP, and protein synthesis were reduced. Concentrations of many amino acids in plasma were abnormal, including reduced valine, leucine, threonine, tryptophan, and tyrosine, as noted by others. Histidine, glutamic acid, and citrulline especially were increased. The intracellular concentrations of the essential amino acids were within normal limits, but citrulline, glycine, and taurine levels were markedly increased while glutamic acid and SAGN (serine + asparagine + glutamine) were decreased. With the second study, intracellular energy-related bioactivities and the abnormal concentrations of the amino acids in plasma were essentially unchanged. However, virtually all the intracellular amino acid concentrations were higher. These results also were in striking contrast to previously reported hemodialysis patients in whom the intracellular concentrations of the branched-chain amino acids and methionine as well as protein synthesis were strikingly decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Family management in the prevention of morbidity of schizophrenia: the adjustment of the family unit.

Changes in the functioning of family members were assessed during a randomly controlled study of community management of schizophrenia. Eighteen families who completed two years community management based upon behavioural family therapy were compared with 18 families who received patient oriented management with family support. Families receiving family management reported less disruption of activities, reductions in physical and mental health problems, and less subjective burden than those receiving the patient oriented approach. It is concluded that the benefits of family management extend beyond the reduction in clinical and social morbidity of the index patient to beneficial effects for the family as a whole.

Family Therapy↗
PubMed1985

Ventricular myocardial catecholamines in primates.

We report myocardial catecholamine levels in primate ventricles assayed by high-pressure liquid chromatography with electrochemical detection. The norepinephrine content of the left ventricles of 11 monkeys (four rhesus and seven cynomolgus) was 1391 +/- 362 ng/gm (+/-SD) with a definite gradient from base (highest) to apex (lowest concentration). Dopamine and epinephrine were present in much lower concentrations (51.8 +/- 24.5 ng/gm and 59.2 +/- 20.0 ng/gm, respectively), but were similarly distributed throughout the left ventricle. There was considerable variation in norepinephrine concentration between animals, but the dopamine/norepinephrine ratio was very consistent within a given animal, averaging 3.7% +/- 1.4%. These values are probably indicative of what normal concentrations of catecholamines are likely to be in humans, and provide a basis for interpretation of results obtained in disease studies.

Animals↗
PubMed1983

Effects of amino acid infusions on cell metabolism in hemodialyzed patients with uremia.

Eighteen uremic patients received i.v. infusions of a mixture of amino acids three times per week for 3 months in an effort to improve cellular amino acid imbalance and related cell bioactivities. They were a subset of 42 uremic patients stabilized by maintenance hemodialysis and were characterized by reduced cellular levels of threonine, isoleucine, methionine, and ornithine, with increased levels of aspartate, glycine, arginine, tyrosine, and phenylalanine. Protein synthesis (3H-leucine incorporation), energy level [energy charge = (ATP + 1/2 ADP)-(ATP + ADP + AMP)], and activity of the rate-limiting glycolytic enzyme pyruvate kinase were reduced in these patients compared with 32 control normal subjects. The circulating leukocyte (88 +/- 5% granulocytes) was used as a cell model. Previously, multiple regression best-subset analysis showed that a combination of the cell levels of aspartate, valine, isoleucine, ornithine, lysine, and tryptophan could "explain" 40% of the variance in protein synthesis in these patients. Similarly, a combination of the levels of aspartate, glutamic acid, glycine, ornithine, and arginine were "predictive" of the level of energy charge. We hypothesized that protein synthesis and energy level would be improved if the amino acid infusions normalized the intracellular levels of those amino acids that were predictive of the bioactivities. After 3 months of amino acid infusions, levels of the predictive intracellular amino acids were not improved, but deviated further from baseline values. Failure to detect significant improvement in the cell bioactivities is attributed to inability to correct the imbalance in the intracellular amino acid pool.

Amino Acids↗