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Biomedical subjects

D R White

Publications and source records attributed to D R White.

At least 19 recordsLinked to original sources
PubMed2001

Phase I study of twice-weekly gemcitabine and concurrent thoracic radiation for patients with locally advanced non-small-cell lung cancer.

PURPOSE: To determine the maximum tolerated dose (MTD) and dose-limiting toxicity of twice-weekly gemcitabine and concurrent thoracic radiation in patients with Stage IIIa/IIIb non-small-cell lung cancer (NSCLC). METHODS AND MATERIALS: Seventeen patients with histologically confirmed Stage IIIa and IIIb NSCLC were studied. Gemcitabine was administered via a 30-min i.v. infusion twice weekly for 6 weeks concurrent with 60 Gy of thoracic radiation. Gemcitabine, starting at a twice-weekly dose of 10 mg/m2 (20 mg/m2/week), was escalated in 10-15 mg/m2 increments in successive cohorts of 3 to 6 patients until dose-limiting toxicity was observed. RESULTS: Of the 17 patients entered, 16 were evaluable for toxicity. The dose-limiting toxicity at 50 mg/m2 given twice weekly (100 mg/m2/week) was Grade 3 pneumonitis observed in 1 patient, Grade 3 pulmonary fibrosis in a second patient, and Grade 4 esophagitis observed in two additional patients. Twice-weekly gemcitabine at a dose of 35 mg/m2 was determined to be the MTD. The overall response rate for the 16 evaluable patients was 88%. The median survival for the entire group is 16.0 months. CONCLUSIONS: The MTD of twice-weekly gemcitabine is 35 mg/m2 (70 mg/m2/week) given with thoracic radiation. A Phase II study within the Cancer and Leukemia Group B to ascertain the potential efficacy of this treatment regimen is in development.

Adult↗
PubMed2001

Interpersonal influence and disordered eating behaviors in adolescent girls: the role of peer modeling, social reinforcement, and body-related teasing.

This study investigated the association between interpersonal relationships, eating behaviors, and body esteem in a sample of adolescent girls. Participants included 876 girls who completed questionnaires regarding body esteem, eating behavior, peer pressure, and interpersonal relationships. Peer pressure was a strong predictor of eating behavior and body esteem after controlling for interpersonal variables. High externalized self-perceptions, self-reported teasing, and attributions about the importance of weight and shape for popularity and dating were important predictors of both body esteem and eating behavior. Also, girls who were nominated as popular by peers were more likely to engage in disordered eating and have lower body esteem. Results highlight the need for eating disorder prevention at the level of the peer group. Programs should focus on decreasing pressure to be thin, acceptance by peers for attributes other than appearance, and combating weight- and shape-related teasing within the school system.

Journal Article↗
PubMed2001

Function of the eustachian tube after weekly exposure to pepsin/hydrochloric acid.

OBJECTIVE: To determine the effects of repeated pepsin/hydrochloric acid (HCl) exposure on the eustachian tube (ET). STUDY DESIGN AND SETTING: ET function was studied in 22 rats. Group I (control) rats received transtympanic phosphate buffered saline solution; groups II (0.5 mg/ml) and III (2.0 mg/ml) received transtympanic pepsin/HCl. Test solutions were applied on day 0 with ET function evaluated on days 1, 2, 3, and 7 after exposure. Each 7-day period represents 1 cycle; all groups underwent 4 cycles. ET function was evaluated using passive opening and closing pressure, and active clearance of positive and negative pressure tests. RESULTS: Rats exposed to pepsin/HCl had elevated passive opening pressures and a decreased ability to clear positive and negative pressure. A temporal relationship exists. CONCLUSION: The results suggest middle ear exposure to pepsin/HCl leads to ET dysfunction in rats, and that this dysfunction is enhanced with repeated exposures. SIGNIFICANCE: Gastroesophageal reflux may induce ET dysfunction.

Animals↗
PubMed2001

Late-phase allergy and eustachian tube dysfunction.

OBJECTIVE: This study investigated the role of late-phase allergy in the development of otitis media with effusion. METHODS: Brown Norway rats were sensitized to ovalbumin and later challenged transtympanically. Eustachian tube ventilatory function was assessed 2, 4, 8, 24, 28, and 32 hours postchallenge by measuring passive opening and closing pressures, active clearance of positive and negative middle ear pressure, and mucociliary clearance. RESULTS: The results demonstrate that exposure to transtympanic allergen induces eustachian tube dysfunction and subsequent formation of effusion. Allergic animals showed significant increases in passive and active opening pressures, as well as a decreased ability to actively clear middle ear pressure. Finally, the mucociliary was significantly impaired in all sensitized rats exposed to transtympanic allergen. CONCLUSION: These findings demonstrate that late-phase allergy leads to significant eustachian tube dysfunction and subsequent formation of effusion by impairing the ventilatory and clearance functions of the eustachian tube.

Animals↗
PubMed2001

Transient inflammation and dysfunction of the eustachian tube secondary to multiple exposures of simulated gastroesophageal refluxant.

Gastroesophageal reflux is a common problem in the newborn and preschool periods. Recent research suggests that it may be related to eustachian tube dysfunction and otitis media with effusion. The purpose of this experiment was to investigate the relationship between simulated gastroesophageal reflux and eustachian tube dysfunction. Rat middle ears were repeatedly exposed (transtympanically) to pepsin in hydrochloric acid or to phosphate-buffered saline solution. Their eustachian tube function was evaluated by assessing passive opening and passive closing pressures, and active clearance of positive and negative pressure. The passive pressure function tests showed variable results. The rats exposed to pepsin in hydrochloric acid had an impaired ability to clear positive and negative pressure from the middle ear as compared to the rats exposed only to phosphate-buffered saline solution. The results demonstrate that multiple middle ear exposures to pepsin in hydrochloric acid leads to eustachian tube dysfunction in rats.

Animals↗
PubMed2001

Body-esteem scale for adolescents and adults.

Body esteem (BE) refers to self-evaluations of one's body or appearance. This article outlines a BE questionnaire for adolescents and adults that has 3 subscales: BE-Appearance (general feelings about appearance), BE-Weight (weight satisfaction), and BE-Attribution (evaluations attributed to others about one's body and appearance). The subscales have high internal consistency and 3-month test-retest reliability. Females scored lower than males on BE-Weight and BE-Appearance. BE-Weight was the only subscale uniquely related to weight, especially in females, with heavy individuals tending to be dissatisfied with their weight. BE-Appearance was the only subscale that consistently predicted self-esteem. BE-Appearance and BE-Weight covaried more with Neeman and Harter's (1986) Appearance subscale than with other self-esteem subscales; BE-Attribution covaried more with social self-esteem subscales than did BE-Appearance and BE-Weight.

Adolescent↗
PubMed2000

Phase II trial of adjuvant radiation and intraperitoneal 5-fluorouracil for locally advanced colon cancer: results with 10-year follow-up.

PURPOSE: To determine the toxicity, disease-free survival, and overall survival for patients with Modified Astler-Coller (MAC) B2-3 or C1-3 colon cancer receiving adjuvant radiation and sequential intraperitoneal 5-fluorouracil (5-FU). METHODS AND MATERIALS: From August 1984 to June 1989, 45 patients were accrued to this Phase II trial and received a 21-week course of intraperitoneal 5-FU (20 mg/kg/d x 5) and external beam radiation. The radiation was delivered to the tumor bed and para-aortic lymph nodes in two split-courses of 22.5 Gy, alternating with the first two cycles of chemotherapy. All patients then received 4 additional cycles of intraperitoneal 5-FU. RESULTS: The therapy was well tolerated with 4 patients experiencing Grade 3 peritonitis. Four patients developed small bowel obstruction requiring surgery; in each instance, recurrent tumor was found at the time of laparotomy. The median and overall survivals at 10 years were 9.3 months and 53% respectively. Local failures were infrequent, occurring in only 11% of patients treated. CONCLUSIONS: Sequential intraperitoneal 5-FU and tumor-bed/para-aortic irradiation is tolerable in patients with resected colon cancer. Although the incidence of local and regional relapse appeared to be lower than anticipated, this did not appear to translate into improved survival.

Adult↗
PubMed2000

Phase II study of pyrazine diazohydroxide (NSC 361456) for advanced non small-cell lung cancer.

Pyrazine diazohydroxide (NSC 361456) (PZDH) was selected for further development after demonstrating more stability than its parent compound and significant antitumor activity in a number of in vivo tumor models. Its proposed mechanism of action is through the formation of DNA adducts via the reactive pyrazine diazonium ion. The aim of this phase II trial was to determine the toxicity and antitumor activity of PZDH in advanced non small-cell lung cancer (NSCLC). From May 1995 through April 1996, 17 chemo-therapy-naive patients were entered into this study. PZDH was administered via a 5-minute intravenous bolus injection at a dose of 100 mg/m2 for 5 days and repeated every 42 days. Per interim guidelines, the study was closed early due to lack of activity. Seventeen patients were evaluable for toxicity while 15 patients were evaluable for response. The median number of cycles administered was 2 (range, 1-7). Toxicity was moderate with grade 3-4 thrombocytopenia being the most common and occurring in six of 17 patients. Of the 15 patients evaluable for response, no partial or complete responses were observed (95% confidence interval [CI]: 0%-22%), while seven patients had stable disease and eight patients progressed during therapy. All but one patient have died. The median survival for the group is 6.6 months (95% CI: 3.4-10.8 months). PZDH possesses modest but acceptable hematologic toxicity when delivered at the above dose and dosing scheme. Our results demonstrate that PZDH has no clinical activity in advanced NSCLC with this dose and schedule.

Journal Article↗
PubMed1999

Intra- and interoperator variations in region-of-interest drawing and their effect on the measurement of glomerular filtration rates.

PURPOSE: Quantitative results are often obtained from images after drawing regions of interest (ROIs) about the organ or area being evaluated. The accuracy and reproducibility of ROIs is an important aspect of quality-control protocols. Attempts to increase ROI accuracy and precision by generating them automatically must be compared with manually processed images to evaluate the success of the automatic methods. Operators' abilities to reproduce ROIs and the effect this has on the reproducibility of estimating glomerular filtration rate from renograms were assessed. METHODS: Estimation of the glomerular filtration rate using Sampson's method requires a) exclusion ROIs around both kidneys for background subtraction, b) whole-kidney ROIs, and c) exclusion ROIs for the collecting system. Two nuclear medicine professionals were asked to produce glomerular filtration rate estimates for 20 patients with diverse renal function. This was repeated 1 month later. The intra- and interoperator variations were calculated for the glomerular filtration rate results and on a pixel basis for the ROIs. RESULTS: THE percentage of common pixels, on average, for a) intraoperator repeats and b) interoperator comparisons were a) 95%, 94%, 85%, and b) 94%, 93%, and 81% for region types 1, 2, and, 3, respectively. Analysis of variance for the glomerular filtration rate estimates showed significant variations in estimates for left kidneys (P < 0.025) but none (P > 0.1) for right kidneys. CONCLUSION: Spatial reproducibility in ROI drawing does not necessarily relate directly to the associated quantitative reproducibility.

Glomerular Filtration Rate↗
PubMed1998

Early pregnancy detection and the hormonal characterization of embryonic-fetal mortality in fallow deer (Dama dama).

The objectives of this investigation were to 1) determine serum concentrations of progesterone (P4), estrone sulfate (E1S) and pregnancy-specific protein B (PSPB) from estrus synchronization through mid-gestation in the fallow doe (Dama dama) and 2) characterize the hormonal profiles of does whose embryos or fetuses died in utero. Ten fallow does were synchronized for 14 d with an intravaginal P4-releasing device (CIDR) and were naturally mated after CIDR removal. Blood samples were collected at CIDR insertion, CIDR removal and at intervals through Day 203 post-CIDR removal for analysis of P4, E1S and PSPB by radioimmunoassay (RIA). Ultrasonography was performed on Days 49 and 69 post-CIDR removal. Serum P4 at the time of CIDR insertion was 4.8 +/- 0.6 ng/ml, and at CIDR withdrawal it was 6.2 +/- 0.3 ng/ml. Concentrations of E1S and PSPB were nondetectable at CIDR insertion. Serum E1S was highest at Day 93, and PSPB was first detectable in pregnant does at Days 27 to 30 post-CIDR withdrawal. Ultrasonography on Day 49 revealed that 6 does were pregnant, 2 were not pregnant and 2 others were diagnosed originally as early pregnant. At Day 69, ultrasonography revealed that 6 does (60%) were pregnant and 4 (40%) were not. A comparison of the ultrasonographic and hormonal data indicated that the 2 does diagnosed as early pregnant on Day 49 had conceived but had lost the pregnancy. A third doe which was pregnant on Day 69 lost the fetus later in gestation. Hormonal profiles of does whose embryo or fetus had died were characterized by erratic P4 and E1S profiles, with PSPB becoming undetectable in the 3 does by Days 49, 65 and 80 post-CIDR removal. These data 1) demonstrate the timing for the collection of serum samples for determining early pregnancy in fallow does using 3 hormonal methods and 2) characterize the hormonal profiles of 3 fallow does with embryonic-fetal loss.

Animals↗
PubMed1998

Effects of nimodipine on noise-induced hearing loss.

The effects of nimodipine, a calcium channel blocker, on noise-induced hearing loss were examined in gerbils. Animals were implanted subcutaneously with a timed-release pellet containing either nimodipine (approximately 10 mg/kg/day) or placebo and exposed to either 102 or 107 dBA noise. Serum levels were tested in two subjects and were in the range known to protect humans from cerebral artery vasospasm and ischemia-related neurologic deficits. Nimodipine and control groups had similar amounts of noise-induced (a) permanent threshold shift; (b) reductions in distortion product otoacoustic emissions; (c) reductions in tuning and suppression of the compound action potential; and (d) loss of outer hair cells. The results suggest that nimodipine, at a dose which results in clinically relevant serum levels, does not provide protection from the effects of moderately intense noise exposures.

Action Potentials↗
PubMed1998

An assessment of two methods for generating automatic regions of interest.

Two fully automatic methods for generating regions of interest (ROIs) for nuclear medicine images are described and assessed. One of these, involving registration of a previously defined ROI onto a new image, uses spatial information and is appropriate for two- and three-dimensional images which may be static or dynamic. The other method is based on artificial neural networks and uses temporal information. It is appropriate for dynamic images only. The registration method has been tested using 10 pairs of stress and redistribution images obtained from cardiac perfusion SPET. Regions of interest of the left ventricular muscle, defined on the stress images, were registered onto the redistribution images, where they were compared with reproducibility of manually drawn ROIs. Both methods were tested on 17 99Tcm-MAG3 kidney dynamic studies, where the original ROIs corresponding to both kidneys and the bladder were defined using the COST B2 hybrid phantom. Our results indicate that neither method is as reliable as having ROIs redrawn by the operator, although there are indications that an artificial neural network which combines the use of the spatial and temporal information could prove useful for dynamic studies.

Automation↗
PubMed1998

Effectiveness of intermittent and continuous acoustic stimulation in preventing noise-induced hearing and hair cell loss.

Resistance to noise-induced hearing loss (NIHL) was studied in gerbils exposed either to intermittent or continuous low-level noise prior to an intense noise. Auditory-evoked brainstem response (ABR) thresholds, distortion product otoacoustic emissions (DPOAEs), Q10dB values from compound action potential (CAP) tuning curves, and outer hair cell (OHC) loss were measured for each group. Subjects were exposed to A-weighted noise (octave band noise centered at 2 kHz) on an intermittent (80 dB, 6 h/day) or continuous schedule (74 dB, 24 h/day) for 10 days, allowed to rest in quiet for 2 days, then exposed to intense A-weighted noise (107 dB, 24 h/day) for 2 days. A "noise-only" group was exposed only to the intense noise. Gerbils exposed in both the "intermittent" and "continuous" groups had less (15-30 dB) temporary threshold shift (TTS) than those in the noise-only group. In addition, the continuous group had less (10-15 dB) permanent threshold shift (PTS) than the other groups. These data suggest that resistance to NIHL is evident in both the intermittent and continuous groups when TTS is measured, but resistance to PTS is afforded only by the continuous paradigm. Both paradigms decreased OHC loss as compared to the noise-only group, with the continuous paradigm being most effective. However, neither paradigm conserved DPOAE amplitudes or tuning curve Q10dB values relative to the noise-only group.

Acoustic Stimulation↗
PubMed1996

Artificial insemination, hybridization and pregnancy detection in sika deer (Cervus nippon ).

Artificial insemination (AI) was performed on sika hinds (Cervus nippon ) receiving various dosages of pregnant mare serum gonadotropin (PMSG; Year 1: 0, 50 and 100 IU; Year 2: 100 and 150 IU) and using semen collected from elk and 1 2 elk x 1 2 sika stags. The time from synchronization device removal (CIDR vs norgestomet) to estrus was determined through observations of mounting activity. Methods for pregnancy detection, serum progesterone (P4), estrone sulfate (E1S), pregnancy-specific protein B (PSPB) and ultrasonography, following AI (Year 1: AI, Days 28 and 48 after AI; Year 2: AI, Days 42, 53 and 100 after AI) and a 90-d natural breeding season were investigated. From available production data, body weights were compared among sika and 1 4 elk x 3 4 sika hybrids relative to age. Pregnancy rates tended (P < 0.10) to differ relative to PMSG treatment and sire; administration of 0 IU PMSG resulted in fewer hinds becoming pregnant to AI than 50 or 100 IU of PMSG. Hinds receiving 100 IU of PMSG had higher (P < 0.05) pregnancy rates than hinds receiving 150 IU PMSG. Time to standing estrus did not differ (P > 0.10) between the CIDR and norgestomet groups. Pregnancy rates 50 d after a 90-d breeding season were similar (P > 0.10) between ultrasound (70.9%) and PSPB (61.6%). Serum P4 after 90 d in breeding groups and 50 d after stag removal were higher (P < 0.05) for pregnant than open hinds. Pregnancy rates (Year 1) 48 d after AI were similar (P > 0.10) between ultrasound (49.0%) and PSPB (37.3%). Serum P4 28 and 48 d after AI were higher (P < 0.05) for pregnant than open hinds. Serum E1S was higher (P < 0.01) for pregnant than open hinds 48 d after AI. Pregnancy rates (Year 2) 100 d after AI did not differ (P > 0.10) between ultrasound and PSPB (66.7%). Serum P4 was higher (P < 0.03) in pregnant than open hinds at 42, 53 and 100 d after AI. At 100 d after AI, pregnant hinds had higher (P < 0.002) serum E1S than open hinds. At 6 to 8 and 11 to 13 mo of age, 1 4 elk x 3 4 sika males tended (P < 0.08) to be heavier than sika males, while 1 4 elk x 3 4 sika females were heavier (P < 0.05) than sika females at all ages. In summary, this study documents the use of AI and methods for pregnancy detection in sika hinds as well as preliminary information regarding the production of elk-x-sika hybrids.

Journal Article↗
PubMed1996

Combination cisplatin and carboplatin in advanced squamous cell carcinoma of the head and neck.

Twenty-three patients with advanced squamous cell carcinoma of the head and neck who had received no prior chemotherapy were treated with carboplatin 350 mg/m2 followed by cisplatin 50 mg/m2 every 28 days. Twenty-one of 23 patients were evaluable for response and toxicity. Eight patients (38%) achieved complete response (CR) or partial response (PR) with 2 CR and 6 PR. The overall median survival was 8.4 months (range 19 days-56+ months). The major toxicity was hematological with grade III/IV granulocytopenia in 32% and grade III/IV thrombocytopenia in 32%. There was very little nonhematological toxicity and no nephrotoxicity. There were no therapy-related deaths. The combination carboplatin/cisplatin is tolerable in patients with squamous cell carcinoma of the head and neck, with objective responses in 38%; however, the response rate was not superior to single-agent carboplatin or cisplatin. Further studies with a higher dose of cisplatin should be considered.

Adult↗