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Biomedical subjects

R Harman

Publications and source records attributed to R Harman.

13 recordsLinked to original sources
PubMed2006

Pathogen inactivation of Leishmania donovani infantum in plasma and platelet concentrates using riboflavin and ultraviolet light.

BACKGROUND AND OBJECTIVES: Leishmania is transmitted by the bite of the phlebotomine sandfly or by transfusion of infected blood products. Leishmaniasis currently poses a significant problem in several parts of the world, and is an emerging problem in others. The Mirasol PRT technology is based on the use of riboflavin and ultraviolet light to generate chemical reactions in the nucleic acids of pathogens, which prevents replication and leads to inactivation. The intent of this study was to examine the ability of the Mirasol PRT System to kill the Leishmania parasite in human plasma and platelet concentrates. MATERIALS AND METHODS: In visceral Leishmaniasis, amastigotes are present in the blood and in the reticuloendothelial system within monocytes. For each unit of plasma or platelets treated, isolated mononuclear cells obtained from 100 ml of normal donor whole blood were incubated with 1.0 x 10(8) Leishmania donovani infantum promastigotes to produce amastigote-laden macrophages. The infected macrophages were added to 250 ml of human plasma or to 250 ml of platelet concentrates. Infected units were cultured pretreatment in 10-fold serial dilutions to determine the limits of detection. Thirty millilitres of 500 microM riboflavin was added to each unit, which was then illuminated with 5.9 J/cm2 of ultraviolet light (6.24 J/ml). After treatment and after 2 months of frozen storage, plasma units were cultured in 10-fold serial dilutions. Platelets were cultured on the day of treatment and on day 5 of storage post-illumination. RESULTS: A 5 log reduction of Leishmania was demonstrated in five of six units of plasma, and a 7 log reduction of Leishmania was demonstrated in one plasma unit. A 5 log reduction of Leishmania was demonstrated in five of six units of platelets, and a 6 log reduction of Leishmania was demonstrated in one unit. CONCLUSIONS: There is no donor screen for Leishmania and other pathogens constantly emerging in our blood supply. The Mirasol PRT System for Platelets and Plasma is an effective means of killing Leishmania and other emerging pathogens in these blood products.

Animals↗
PubMed2004

Determinants of outcome in melanoma patients with cerebral metastases.

PURPOSE: To analyze prognostic factors, effects of treatment, and survival for patients with cerebral metastases from melanoma. PATIENTS AND METHODS: All melanoma patients with cerebral metastases treated at the Sydney Melanoma Unit between 1952 and 2000 were identified. From 1985 to 2000, patients were diagnosed and treated using consistent modern techniques and this cohort was analyzed in detail. Multivariate analysis of prognostic factors for survival was performed. RESULTS: A total of 1137 patients with cerebral metastases were identified; 686 were treated between 1985 and 2000. For these 686 patients, the median time from primary diagnosis to cerebral metastasis was 3.1 years (range, 0 to 41 years). A total of 646 patients (94%) have died as a result of melanoma. The median survival from the time of diagnosis of cerebral metastasis was 4.1 months (range, 0 to 17.2 years). Treatment was as follows: surgery and postoperative radiotherapy, 158 patients; surgery alone, 47 patients; radiotherapy alone, 236 patients; and supportive care alone, 210 patients. Median survival according to treatment received for these four groups was 8.9, 8.7, 3.4, and 2.1 months, respectively; the differences between surgery and nonsurgery groups were statistically significant. On multivariate analysis, significant factors associated with improved survival were surgical treatment (P <.0001), no concurrent extracerebral metastases (P <.0001), younger age (P =.0007), and longer disease-free interval (P =.036). Prognostic factors analysis confirmed the important influence of patient selection on treatment received. CONCLUSION: This large series documents the characteristics of patients who developed cerebral metastases from melanoma. Median survival was dependent on treatment, which in turn was dependent on patient selection.

Adolescent↗
PubMed1999

Reoperative parathyroid surgery in the era of sestamibi scanning and intraoperative parathyroid hormone monitoring.

HYPOTHESIS: Results of reoperative parathyroid surgery (RPS) have improved with the advent of sestamibi parathyroid subtraction scanning and intraoperative parathyroid hormone (IOPTH) monitoring. DESIGN: Retrospective review of patient histories, preoperative localization studies, operative data, including IOPTH monitoring, and outcomes for patients undergoing recent RPS at a single institution. Follow-up was complete (mean, 20 months). SETTING: Tertiary care referral center. PATIENTS: All patients undergoing RPS for benign persistent or recurrent primary hyperparathyroidism during the period 1989 to 1997. MAIN OUTCOME MEASURES: Overall cure rate and operative morbidity from RPS; sensitivity and accuracy of preoperative localization studies; and prediction of cure from IOPTH monitoring. RESULTS: The study group included 124 patients (87 women and 37 men). Hypercalcemia was corrected in 109 patients (88%). Permanent recurrent laryngeal nerve injury occurred in 0.8% and permanent hypoparathyroidism in 13% of patients. Test sensitivities and accuracies, respectively, were as follows: ultrasound with biopsy, 90% and 82%; sestamibi parathyroid subtraction scanning, 82% and 67%; and ultrasound alone, 75% and 65%. Level of IOPTH was predictive of cure in all patients with a 70% or greater fall from baseline at 20 minutes after excision. Persistent multigland disease was the major cause for reoperative failure (73%). CONCLUSIONS: Neither cure rates nor operative morbidity have changed appreciably over the past 2 decades, despite the introduction of sestamibi parathyroid subtraction scanning and IOPTH monitoring. Multigland disease continues to represent the principal cause of failure in RPS despite the routine use of preoperative localization studies. Thus far, increasing the stringency of IOPTH monitoring from a 50% to 70% decline from baseline levels has been predictive of cure, even in multigland disease. Most missed abnormal glands reside in normal anatomic locations, and the need for multiple operations, not just the reoperation, results in the increased morbidity seen with RPS.

Adolescent↗
PubMed1981

Erythrocyte glycosphingolipids of four siblings with the rare blood group p phenotype and their parents.

Erythrocytes that exhibit the rare blood group p phenotype lack the P antigen (globotetraosylceramide) and the Pk antigen (globotriaosylceramide). This phenotype is inherited as an autosomal recessive condition and the red cells of heterozygous individuals, parents and children of p persons, are serologically normal but no chemical analyses of their red cells have been reported. We have studied an unusual family in which all five children exhibit the p phenotype. In addition to the abnormalities described previously, the erythrocytes of four siblings had twice the normal concentration of lactotriaoslyceramide and lactoeotetraosylceramide. These cells also contained 3-5 times as much sialosyllactoneotetraosylceramide and up to a two-fold increase in Gm3 ganglioside. The glycolipids of the parents'erythrocytes were normal. Electrophoretic analysis of the glycoproteins of the proposita's erythrocytes revealed no abnormalities, but her erythrocyte membranes contained approximately 35% less galactosamine than normal red cells. This abnormality resulted from a marked decrease in galactosamine that was soluble in chloroformmethanol. The lipid-extracted residue, which contained the glycoproteins, had a normal galactosamine content.

Blood Group Antigens↗
PubMed1970

Isolation of a pure dextranase from Penicillium funiculosum.

A dextranase, produced by Penicillium funiculosum, was purified 1,000-fold to yield the enzyme which was demonstrated by gel electrophoresis and electrofocusing to be a homogeneous protein. The purification method included acetone partition, ammonium sulfate fractionation, gel filtration, iron defecation and precipitation, and diethylaminoethyl-cellulose chromatography. The pure enzyme was also obtained by preparative gel electrophoresis. Gel-permeation chromatography indicates a molecular weight of 41,000. An isoelectric pH of 4.6 was established by electrofocusing. A 1-mg amount of the enzyme hydrolyzes a dextran substrate to yield 27,000 isomaltose reducing units in 2 hr.

Chemical Precipitation↗