Biomedical subjects

David Larson

Publications and source records attributed to David Larson.

7 recordsLinked to original sources

PubMed2005

Characterization of a human reference standard for antibody to Plasmodium falciparum merozoite surface protein 1(42).

Volunteers vaccinated with a candidate malaria vaccine containing merozoite surface protein 1(42) (MSP-1(42)) exhibit antibodies to MSP-1(42) that are measured by enzyme-linked immunosorbent assay (ELISA). The purpose of this study was to make a human reference standard for MSP-1(42) antibody measured in absolute quantity units using pooled plasma samples known to contain high titers of MSP-1(42) antibody based on previous ELISA results. Immobilized metal affinity chromatography was used to determine the amount of MSP-1(42) antibody in this plasma pool. Hexahistidine-tagged MSP-1(42) antigen adsorbed to nickel-chelating resin was used to capture MSP-1(42) antibody from the plasma pool. The intact MSP-1(42) antibody-antigen complexes were eluted and total IgG was measured by an ELISA standardized against purified human IgG. In this way, the human reference standard was determined to contain 48.3 microg/mL of MSP-1(42) antibody. This reference standard may be useful as a quantitative working standard for measuring MSP-1(42) antibody response in future vaccine clinical trials involving MSP-1.

Animals↗

PubMed2004

Phase II study of temozolomide and thalidomide with radiation therapy for newly diagnosed glioblastoma multiforme.

PURPOSE: The chemotherapeutic agent temozolomide (TMZ) and the antiangiogenic agent thalidomide have both demonstrated antitumor activity in patients with recurrent malignant glioma. The objectives of this study were to determine if the combined strategy of these oral agents with radiation therapy (RT) is associated with an improved median survival of patients with newly diagnosed glioblastoma multiforme and to evaluate toxicity. METHODS AND MATERIALS: Sixty-seven patients were enrolled in this trial. Radiotherapy parameters were a total dose of 60 Gy delivered in 2 Gy fractions over 6 weeks. Temozolomide was administered starting the first day of RT at 150 mg/m(2) daily for 5 days every 4 weeks for the first cycle and escalated to a maximum dose of 200 mg/m(2). Thalidomide was started on Day 7 of RT at 200 mg and escalated by 100-200 mg every 1-2 weeks depending on patient tolerance, to a maximum of 1,200 mg daily. RESULTS: Sixty-one patients have progressed, with a median time to progression of 22 weeks. Fifty-six patients have died, and the median survival was 73 weeks. CONCLUSIONS: This strategy of combination TMZ, thalid and RT was relatively well tolerated with favorable survival outcome for patients with GM when compared to patients not treated with adjuvant chemotherapy and similar to those who have received nitrosourea adjuvant chemotherapy. It is unclear the added advantage thalid has in combination with TMZ for this patient population.

Adult↗

PubMed2004

Proton magnetic resonance spectroscopy imaging in the evaluation of patients undergoing gamma knife surgery for Grade IV glioma.

OBJECT: The purpose of this study was to assess the differences in spatial extent and metabolic activity in a comparison of a radiosurgical target defined by conventional strategies that utilize the enhancing lesion and a metabolic lesion defined by proton magnetic resonance spectroscopy (MRS) imaging. The authors evaluated whether these differences manifest themselves in the clinical outcome of patients and assessed the value of incorporating 1H-MRS imaging-derived spatial information into the treatment planning process for gamma knife surgery (GKS). METHODS: Twenty-six patients harboring Grade IV gliomas who had previously been treated with external-beam radiation therapy were evaluated by comparing the radiosurgically treated lesion volume with the volume of metabolically active tumor defined on 1H-MRS imaging. The cohort was evenly divided into two groups based on the percentage of overlap between the radiosurgical target and the metabolic lesion volumes. Patients with a percentage of overlap greater than 50% with respect to the metabolic lesion volume were classified as low risk and those with an overlap less than 50% were classified as high risk. Kaplan-Meier estimators were calculated using time to progression and survival as dependent variables. The metabolite levels within the metabolic lesion were significantly greater than those within the radiosurgical target (p < or = 0.001). The median survival was 15.7 months for patients in the low-risk group and 10.4 months for those in the high-risk group. This difference was statistically significant (p < 0.01). CONCLUSIONS: Analysis of the results of this study indicates that patients undergoing GKS may benefit from the inclusion of 1H-MRS imaging in the treatment planning process.

Adult↗

PubMed2003

Dimensions of religiosity and their relationship to lifetime psychiatric and substance use disorders.

OBJECTIVE: The role of religion in mental illness remains understudied. Most prior investigations of this relationship have used measures of religiosity that do not reflect its complexity and/or have examined a small number of psychiatric outcomes. This study used data from a general population sample to clarify the dimensions of religiosity and the relationships of these dimensions to risk for lifetime psychiatric and substance use disorders. METHOD: Responses to 78 items assessing various aspects of broadly defined religiosity were obtained from 2,616 male and female twins from a general population registry. The association between the resulting religiosity dimensions and the lifetime risk for nine disorders assessed at personal interview was evaluated by logistic regression. Of these disorders, five were "internalizing" (major depression, phobias, generalized anxiety disorder, panic disorder, and bulimia nervosa), and four were "externalizing" (nicotine dependence, alcohol dependence, drug abuse or dependence, and adult antisocial behavior). RESULTS: Seven factors were identified: general religiosity, social religiosity, involved God, forgiveness, God as judge, unvengefulness, and thankfulness. Two factors were associated with reduced risk for both internalizing and externalizing disorders (social religiosity and thankfulness), four factors with reduced risk for externalizing disorders only (general religiosity, involved God, forgiveness, and God as judge), and one factor with reduced risk for internalizing disorders only (unvengefulness). CONCLUSIONS: Religiosity is a complex, multidimensional construct with substantial associations with lifetime psychopathology. Some dimensions of religiosity are related to reduced risk specifically for internalizing disorders, and others to reduced risk specifically for externalizing disorders, while still others are less specific in their associations. These results do not address the nature of the causal link between religiosity and risk for illness.

Adult↗

PubMed2002

Technical skills for weight loss: preliminary data from a randomized trial.

BACKGROUND: Optimal behavioral interventions for sustainable weight loss are uncertain. We therefore conducted a study among overweight/obese women comparing conventional dietary counseling of individuals (counseling-based intervention) to a novel, group-based skill-building intervention. METHODS: Eighty subjects were randomly assigned to either the counseling-based or to the skill-building intervention. Outcomes included weight loss, dietitian hours per group and per unit weight loss, and dollars spent per group and per unit weight lost. RESULTS: Weight loss at 6 months (follow-up rate 61.3%) in the counseling-based group was 8.8 lb (P = 0.0001), and in the skill-building group was 3.8 lb (P = 0.01). A total of 160 dietitian hours were required for the counseling-based group, and 131 for the skilled-building group. The counseling-based group cost an average of $21 per pound lost, while the skill-building cost an average of $48 per pound lost (P = 0.16). CONCLUSIONS: At 6 months, individualized office-based counseling produced more weight loss than a skill-building approach and cost less than half as much per pound of weight loss. Longer-term follow-up is required to determine if, as hypothesized, the skill-building intervention produces more sustainable weight loss.

Adult↗

PubMed2002

Anterolateral thigh fasciocutaneous island flaps in perineoscrotal reconstruction.

This study presents the authors' experience using the anterolateral thigh fasciocutaneous flap for complex perineal and scrotal reconstruction. Anterolateral thigh fasciocutaneous island flaps were performed in seven patients between January and June of 2000 (six male, one female; mean age, 52 years; age range, 9 to 72 years). Four of the seven patients had scrotal or perineal defects after multiple debridements for Fournier's gangrene. Two of these four had exposed testicles. Three flaps were used for recurrent ischial ulcers. A true septocutaneous perforator (type 1) running between the rectus femoris and the vastus lateralis muscles was found in only two patients. In four patients, the cutaneous perforators were found to be intramuscular, originating from the descending branch (type 2). In the other patient, the musculocutaneous perforator originated from the lateral circumflex femoris artery independently (type 3). In these cases, intramuscular dissections were performed to follow each perforator to its main trunk. Mean follow-up was 8 months (range, 5 to 10 months), and all flaps survived. Three patients developed minor wound dehiscence in the posterior aspect of the perineal wound because of fecal contamination and skin maceration. Both wounds healed secondarily. Scrotal reconstruction with the anterolateral thigh flap gave an excellent aesthetic result. The authors conclude that the anterolateral thigh flap is a reliable flap for perineoscrotal reconstruction.

Adolescent↗

PubMed2002

The Ironson-woods Spirituality/Religiousness Index is associated with long survival, health behaviors, less distress, and low cortisol in people with HIV/AIDS.

The purpose of this study was to determine the reliability and validity of an instrument that measures both spirituality and religiousness, to examine the relation between spirituality and religiousness and important health outcomes for people living with HIV and to examine the potential mediators of these relations. One aim was to determine whether subscales of spirituality, religiousness, or both would be independently related to long survival in people living with AIDS. The Ironson-Woods Spirituality/Religiousness (SR) Index is presented with evidence for its reliability and validity. Four factors were identified on the Ironson-Woods SR Index (Sense of Peace, Faith in God, Religious Behavior, and Compassionate View of Others). Each subscale was significantly related to long survival with AIDS. That is, the long-term survivor (LTS) group (n = 79) scored significantly higher on these factors than did the HIV-positive comparison (COMP) group (n = 200). Long survival was also significantly related to both frequency of prayer (positively) and judgmental attitude (negatively). In addition, the Ironson-Woods SR Index yielded strong and significant correlations with less distress, more hope, social support, health behaviors, helping others, and lower cortisol levels. The relation between religious behavior and health outcomes was not due to social support. Further analyses were conducted, which identified urinary cortisol concentrations and altruistic behavior as mediators of the relation between SR and long survival.

Adult↗