PubMed Health⌕ Search

Biomedical subjects

Kenneth Clark

Publications and source records attributed to Kenneth Clark.

6 recordsLinked to original sources
PubMed2006

Fatal transfusion-associated graft-versus-host disease in an immunocompetent recipient of a volunteer unit of red cells.

BACKGROUND: Transfusion-associated graft-versus-host disease (TAGVHD) is a lethal complication of transfusion of nonirradiated cellular blood components to a susceptible recipient. CASE REPORT: An 82-year-old man underwent cardiac surgery during which he received 6 units of red cells (RBCs) and a 6-unit pool of platelets (PLTs). He was discharged with a normal white blood cell (WBC) count and hemoglobin (Hb) level and a PLT count of 104x10(9) per L. He was readmitted 2 weeks later with a diffuse erythematous rash, a sore throat, and difficulty swallowing. His WBC count was 2.1x10(9) per L, his Hb level was 12.0 g per dL, and his PLT count was 131x10(9) per L. The next day he had worsening cytopenias: WBC count, 1x10(9) per L; Hb level, 10.9 g per dL; PLT count, 104x10(9) per L. He also had diarrhea. A marrow biopsy showed a severe hypoplasia without evidence of malignancy. A skin biopsy showed Grade II GVHD. The patient worsened and despite aggressive therapy he expired on Postoperative Day 42. DNA-based HLA testing of the 12 blood donors was performed. One of the RBC donors was found to be homozygous for an HLA Class I and Class II haplotype in the patient. CONCLUSION: This is the first reported case in the United States of fatal TAGVHD from RBCs in an immunocompetent patient who received a randomly selected unit of RBCs from a donor who was homozygous for a shared HLA haplotype. The policy of selective irradiation should be reexamined.

Aged↗
PubMed2006

Improved estimates of net primary productivity from modis satellite data at regional and local scales.

We compared estimates of net primary production (NPP) from the MODIS satellite with estimates from a forest ecosystem process model (PnET-CN) and forest inventory and analysis (FIA) data for forest types of the mid-Atlantic region of the United States. The regional means were similar for the three methods and for the dominant oak-hickory forests in the region. However, MODIS underestimated NPP for less-dominant northern hardwood forests and overestimated NPP for coniferous forests. Causes of inaccurate estimates of NPP by MODIS were (1) an aggregated classification and parameterization of diverse deciduous forests in different climatic environments into a single class that averages different radiation conversion efficiencies; and (2) lack of soil water constraints on NPP for forests or areas that occur on thin or sandy, coarse-grained soil. We developed the "available soil water index" for adjusting the MODIS NPP estimates, which significantly improved NPP estimates for coniferous forests. The MODIS NPP estimates have many advantages such as globally continuous monitoring and remarkable accuracy for large scales. However, at regional or local scales, our study indicates that it is necessary to adjust estimates to specific vegetation types and soil water conditions.

Climate↗
PubMed2003

Two percent of HIV-positive U.S. blood donors are infected with non-subtype B strains.

To estimate the prevalence of HIV strains other than the predominant HIV-1B subtype in the U.S. blood donor population we genetically and serologically characterized HIV in infected blood donations collected throughout he United States from 1997 to mid-2000. Using a combination of DNA heteroduplex mobility and DNA sequence analyses of the env and gag regions of HIV-1 we determined that 285 of 312 infections were caused by HIV-1B and six by non-subtype B HIV-1 (four HIV-1C, one HIV-1AE, one HIV-1A). Genetic distances of greater than 14% in the envelope V3-V5 region of the four HIV-1C strains indicated that they did not share a recent common origin. HIV-1 group M, N, and O, and HIV-2 specific peptide serological testing of the 20 PCR-negative samples determined that one infection was caused by HIV-2 and none by HIV-1 group N and O. The major risk factor for infection with a non-HIV-1B strain was sex with an HIV-infected person from Africa although three of seven non-HIV-1B-infected subjects did not fit that category. For four of seven non-HIV-1B-infected subjects the subtype detected was consistent with the African country of origin of the infected person or of their sexual partner. The frequency of genetically confirmed non-subtype-B HIV infection in a geographically dispersed group of infected U.S. blood donors in 1977-2000 was therefore 2.0% (6/312).

Blood Donors↗
PubMed2002

Gramene: a resource for comparative grass genomics.

Gramene (http://www.gramene.org) is a comparative genome mapping database for grasses and a community resource for rice. Rice, in addition to being an economically important crop, is also a model monocot for understanding other agronomically important grass genomes. Gramene replaces the existing AceDB database 'RiceGenes' with a relational database based on Oracle. Gramene provides curated and integrative information about maps, sequence, genes, genetic markers, mutants, QTLs, controlled vocabularies and publications. Its aims are to use the rice genetic, physical and sequence maps as fundamental organizing units, to provide a common denominator for moving from one crop grass to another and is to serve as a portal for interconnecting with other web-based crop grass resources. This paper describes the initial steps we have taken towards realizing these goals.

Chromosome Mapping↗
PubMed2002

Anesthetic efficacy of an infiltration in mandibular anterior teeth following an inferior alveolar nerve block.

The purpose of this prospective, randomized, blinded study was to measure the degree of pulpal anesthesia obtained with an inferior alveolar nerve (IAN) block followed by an infiltration in mandibular anterior teeth. Through use of a repeated-measures design, 40 patients randomly received 3 injection combinations at 3 separate appointments: an IAN block followed by a mock lingual infiltration and a mock labial infiltration, an IAN block followed by a mock lingual infiltration and a labial infiltration, and an IAN block followed by a mock labial infiltration and a lingual infiltration. Each IAN block used 3.6 mL of 2% lidocaine with 1:100,000 epinephrine, and each infiltration used 1.8 mL of 2% lidocaine with 1:100,000 epinephrine administered over the lateral incisor apex. Mandibular anterior teeth were blindly pulp tested at 2-minute cycles for 60 minutes following the IAN-infiltration injections. No response from the patient to the maximum output (80 reading) of the pulp tester was used as the criterion for pulpal anesthesia. Anesthesia was considered successful when 2 consecutive 80 readings were obtained within 15 minutes and the 80 reading was sustained for 60 minutes. Anesthesia was considered a failure if 2 consecutive 80 readings were not obtained during the 60 minutes. The results of this study showed that 100% of the patients had lip numbness with all IAN blocks. For the lateral incisor, the success rate of the IAN block alone was 40% and the failure rate was 30%. For the IAN block plus labial infiltration, the success rate was 62% and the failure rate was 12% for the lateral incisor. There was a significant difference (P < .05) between the IAN block alone and the IAN block plus labial infiltration. In conclusion, a labial infiltration, over the lateral incisor apex, of 1.8 mL of 2% lidocaine with 1:100,000 epinephrine following an IAN block significantly improved pulpal anesthesia for the lateral incisor compared with the IAN block alone.

Adult↗