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Biomedical subjects

T J Gilbert

Publications and source records attributed to T J Gilbert.

18 recordsLinked to original sources
PubMed1992

Obesity among Navajo adolescents. Relationship to dietary intake and blood pressure.

We evaluated anthropometric measurements, blood pressures, dietary intakes, and self-perceived body image of 352 Navajo Indian adolescents. Thirty-three percent of the girls and 25% of the boys were obese according to a body mass index criterion. Navajo youth tended to have larger skinfolds than their white (National Health and Nutrition Examination Survey II) and Mexican American (Hispanic Health and Nutrition Examination Survey) counterparts, with the greater difference in the subscapular skinfolds indicating a greater amount of truncal rather than peripheral fat. When divided into lower, middle, and upper thirds of body mass index, systolic and diastolic blood pressures were positively related with increasing body mass index for girls, and systolic blood pressure and body mass index were related among boys. The high prevalence of obese adolescents and the apparent effect of the increased weight on blood pressure in this population indicate the need for interventions aimed at improving dietary habits and fitness levels.

Adolescent↗
PubMed1992

Prevalence of diabetes and impaired glucose tolerance among Navajo Indians.

OBJECTIVE: To estimate the prevalence of diabetes mellitus and impaired glucose tolerance and the incidence of clinically diagnosed diabetes in a community of Navajo Indians. RESEARCH DESIGN AND METHODS: We conducted a survey of a representative Navajo community screened for diabetes 3 yr previously. We used 75-g oral glucose tolerance tests to determine the prevalence of diabetes mellitus and impaired glucose tolerance and conducted medical record reviews to identify cases of diabetes that were diagnosed during routine medical care after the earlier study. RESULTS: By World Health Organization diagnostic criteria, the age-adjusted diabetes prevalence among 419 Navajo Indians 20-74 yr of age was 13.9% (95% confidence interval [CI] 9.2-18.5) for men and 18.4% (95% CI 14-22.8) for women. The ratio of the prevalence of diabetes among the Navajo population studied to that in the general United States population was 2.5. The prevalence of impaired glucose tolerance was 8% (95% CI 3.3-12.7) among men and 12.9% (95% CI 7.9-17.9) among women. Based on clinical diagnoses of diabetes made during routine medical care, mean +/- SE age-adjusted incidence of diagnosed diabetes among men was 8.6 +/- 4.3/1000 person-yr and 11.1 +/- 4.4/1000 person-yr among women. CONCLUSIONS: Although lower than that of some other tribes, the prevalence of diabetes among Navajo Indians is substantially higher than that in the general U.S. population. The high rate of clinical diagnoses suggests that the prevalence of the disease may continue to rise.

Adult↗
PubMed1990

Comparison of computed tomography and magnetic resonance imaging in the evaluation of focal hepatic lesions.

Two combined magnetic resonance (MR) spin-echo pulse sequences at 0.35 T were compared with dynamic bolus contrast-enhanced computed tomography (CT) in the evaluation of focal hepatic lesions. Each combined MR sequence was performed in a separate group of patients. The first group consisted of 76 patients in whom a moderately T1-weighted sequence (spin echo [SE] 500/30 [repetition time/echo time]) was combined with a T2-weighted sequence (SE 2000/60). In the second group, consisting of 68 patients, a more heavily T1-weighted sequence (SE 250/15) was combined with the T2-weighted sequence. All studies were evaluated in a retrospective blinded fashion, with construction of receiver operating characteristic curves. We conclude that, in detection of patients with one or more focal hepatic lesions, either combined MR sequence was comparable to CT. In the detection of individual hepatic lesions, the sensitivity of the combined MR sequence with a moderately T1-weighted sequence (SE 500/30 and 2000/60) was essentially equivalent to CT (79 vs 77%, respectively). Additionally, a combined MR sequence with a heavily T1-weighted pulse sequence (SE 250/15 and 2000/60) was not statistically different than CT (86 vs 80%, respectively). These findings were supported by the receiver operating characteristic analysis.

Adolescent↗
PubMed1990

Evidence for a secular change in obesity, height, and weight among Navajo Indian schoolchildren.

A survey measuring heights and weights of 1969 schoolchildren residing on the Navajo Indian Reservation was conducted in 1989. The findings were compared with National Center for Health Statistics (NCHS) reference data and with surveys of Navajo children from 1955, 1968, and 1981. Approximately twice as many children exceeded the 95th percentile of weight-for-age (11.2% of girls, 12.5% of boys) than would be expected for the NCHS reference population. The mean weight-for-height z scores exceeded those for the NCHS reference population for all ages in both sexes. Compared with data from 1955, mean heights increased 6.1% among boys and 4.4% among girls whereas mean weights increased 28.8% among boys and 18.7% among girls across all age groups. The data suggest that there has been a secular change in height, weight, and obesity in Navajo Indian children over the past 35 y.

Adolescent↗
PubMed1989

Detection of thrombus by using phase-image MR scans: ROC curve analysis.

Spin-echo phase images have been shown to be sensitive to blood flow and have been used to differentiate slow flow from thrombus, with an apparent advantage in comparison with spin-echo intensity images alone. In order to quantify the diagnostic efficacy of phase images, a study was performed comparing the sensitivity and specificity of MR imaging in identifying intravascular thrombus using spin-echo magnitude images alone and combined with phase images. In 45 subjects, 66 vessels with questionable intraluminal signal were reviewed in a blinded manner by four radiologists using seven levels of certitude for the diagnosis of thrombus. Vessels in the thorax, abdomen, and pelvis were included in the evaluation and were selected on the basis of the presence of intraluminal signal, which raised the possibility of intravascular disease. Corroborative studies were available in all cases. Receiver-operator-characteristic curves were constructed for the accuracy of the decision of intraluminal thrombus vs flow signal when using magnitude images alone and when using magnitude plus phase images. Magnitude images identified thrombus with a sensitivity of 35% at a specificity of 90%. On the other hand, combining magnitude image and phase images yielded sensitivities of 85% and 83% at specificities of 90% and 95%, respectively. We conclude that addition of phase images substantially increases the level of confidence in detecting intravascular thrombosis.

Adolescent↗
PubMed1988

Juvenile xanthogranuloma of the kidney.

Juvenile xanthogranuloma is a benign histiocytosis of infancy and childhood characteristically involving the skin, the eye, and, rarely, the lungs, liver and mesothelial structures. This report documents the first known case of renal involvement which is demonstrated by ultrasound and computed tomography.

Granuloma↗
PubMed1988

Normal penile anatomy and abnormal penile conditions: evaluation with MR imaging.

The appearance of the normal penis and of a variety of penile abnormalities on magnetic resonance (MR) images was studied in 55 patients with either medium (0.35 T) or high (1.5 T) magnetic field strengths. Penile morphologic characteristics with anatomic detail of the corpora cavernosa and corpus spongiosum were demonstrated in each patient. MR images clearly displayed congenital anomalies (n = 6), penile prostheses (n = 7), fibrous tissue or hematoma due to trauma (n = 8), and fibrous plaque in Peyronie disease (n = 3). MR imaging also demonstrated urethral (n = 6) and penile (n = 5) neoplasms and allowed tumor staging, thus facilitating the surgical approach.

Adolescent↗
PubMed1988

Evaluation of rebreathing in patients undergoing cataract surgery.

Ten patients undergoing elective cataract surgery with local anesthesia were evaluated for rebreathing using mass spectrometry and arterial blood gas analysis. Results showed a 10 or 51 oxygen-air mixture with an inspired oxygen concentration of 50% (FIO2) administered via a face tent maintained normal blood gases and a satisfactorily low inspired carbon dioxide (FICO2) in conscious patients who were free of lung disease.

Adult↗
PubMed1987

Fluid balance and the adult respiratory distress syndrome.

This study examined the effect of fluid balance on survival in ARDS. Of the 213 patients entered into a prospective data collection study, we evaluated 113 patients who met strict criteria for ARDS. Multiple variables were analyzed for as long as 14 days after intubation including cardiac output, pulmonary capillary wedge pressure, mean blood pressure, intake minus output (I-O), cumulative intake minus output (cum I-O), and change in weight (delta wt). We found significant differences in cum I-O and delta wt between survivors and nonsurvivors on almost every day. Survivors lost weight and had a significantly lower cum I-O compared with nonsurvivors. Logistic regression was used to determine if delta wt and cum I-O could predict survival. Patients who lost 3 kg or more weight had a much higher survival than did those who gained 3 kg or more weight (67 and 0%, respectively, on Day 14). Similar results were obtained using comparably low and high values for cum I-O. The logistic regression equations demonstrated that weight loss and low cumulative I-O correlated with improved survival. Although cause and effect relationships are difficult to determine from these types of analyses, they can be used to formulate prospective studies and predict survival in patients.

Body Weight↗
PubMedDate not supplied

MR imaging of the larynx at 1.5 T.

The normal magnetic resonance (MR) anatomy of the larynx at high field strength (1.5 T) was studied in 2 normal excised larynges and 62 subjects without laryngopharyngeal disease. The two normal excised larynges were imaged using a 1.5 T MR scanner with a 3 in diameter circular surface coil and a GE 9800 CT scanner. The larynges were sectioned transversely and the MR and CT images compared to gross and histologic sections. Unossified hyaline cartilage was intermediate in signal intensity on T1-weighted and proton density images and low in intensity on T2-weighted images. The signal intensity from ossified cartilage was determined by the amount of fatty marrow and was high in intensity on T1-weighted and proton density images and low to intermediate in intensity on T2-weighted images. A chemical shift artifact from high intensity fatty marrow obscured the calcified or ossified cortex of the major laryngeal cartilages along the frequency encoding axis. The epiglottic cartilage demonstrated an intermediate signal intensity on T1-weighted images and higher intensity on proton density and T2-weighted images. The intralaryngeal muscles were well demonstrated as low intensity structures. The conus elasticus and the vocal ligaments were not recognized as distinct structures. However, the quadrangular membrane and a previously undescribed membrane separating the preepiglottic and paralaryngeal spaces were shown on MR as low intensity linear structures. In the 62 subjects, MR at 1.5 T proved excellent for demonstrating the anatomical details of the major laryngeal cartilages, extra- and intralaryngeal muscles, ligaments, and soft tissues including the vocal cords, false vocal cords, laryngeal ventricles, aryepiglottic folds, preepiglottic space, and paralaryngeal spaces. Visibility and intensity of muscles, ligaments, and soft tissues did not depend on age or sex. The intensity pattern of the thyroid and cricoid cartilages demonstrated wide variations in the same sex and age groups, depending on the degree of ossification. However, they did show more high intensity foci in older men than in younger women. Magnetic resonance showed better contrast resolution and finer detail than CT scans in the same subjects. Magnetic resonance imaging at 1.5 T, with either a saddle-shaped neck surface coil or a 3 in diameter circular surface coil, provides high contrast and high spatial resolution images and could be useful for the diagnosis of lesions of the larynx.(ABSTRACT TRUNCATED AT 400 WORDS)

Female↗
PubMedDate not supplied

Serum cholesterol concentrations among Navajo Indians.

Navajo Indians have been reported by earlier investigators to have low concentrations of serum lipids and a low prevalence of hyperlipidemia, as well as low rates of ischemic heart disease. However, no data on serum lipid concentrations among Navajos have been reported for more than two decades. The authors conducted a study to determine the distribution of concentrations of serum total cholesterol (TC), high density lipoprotein cholesterol, low density lipoprotein cholesterol, and triglyceride among persons 25-74 years old living in a representative community on the Navajo Indian reservation. Data are reported for 255 subjects, 105 men and 150 women, ages 25-74 years. The authors compared these data to those for the general population as determined by the second National Health and Nutrition Examination Survey (NHANES II). TC concentrations among Navajo men were similar to those from NHANES II. TC concentrations among younger Navajo women were similar to those for women younger than 55 years from NHANES II, but were significantly lower among older Navajo women. While 27.6 percent of men ages 25-74 years studied in NHANES II had TC concentrations greater than 240 milligrams per deciliter, 33.8 percent of Navajo men had similarly elevated TC. However, the prevalence of serum TC concentrations greater than 240 milligrams per deciliter among Navajo women (17.5 percent) was about half that among women studied in NHANES II (32.9 percent). A similar pattern was found for low density lipoprotein cholesterol. The researchers concluded that Navajo Indians are no longer characterized by low serum lipid concentrations, that increased cholesterol concentrations may be a harbinger of increasing rates of atherosclerotic coronary heart disease among Navajos, and that attention should be directed to primary prevention of hyperlipidemia in Navajo Indian communities.

Adult↗
PubMedDate not supplied

Abnormal Papanicolaou smears and colposcopic follow-up among American Indian and Alaska Native women in the Pacific northwest.

BACKGROUND: Mortality that is due to cervical cancer among American Indian and Alaska Native women in the Pacific Northwest exceeds that among women of other races. Nevertheless, little information is available regarding the prevalence and follow-up of abnormal Papanicolaou smears among American Indian and Alaska Native women in the region. METHODS: We conducted a retrospective review of medical records of American Indian and Alaska Native women seen at 12 Indian Health Service and tribally operated clinics in Washington, Oregon, and Idaho who had an abnormal Papanicolaou smear in 1992. RESULTS: Of 4547 Papanicolaou smear results reviewed, 280 (6.2 percent) had an abnormal result (dysplasia or carcinoma in situ). Of the recommended colposcopies, 167 of 224 (75 percent) were completed. Women with high-grade squamous intraepithelial lesions were more likely to obtain recommended colposcopy than were women with low-grade squamous intraepithelial lesions. Women treated at clinics that referred patients to outside providers for colposcopy were more likely to have colposcopy than were those who were offered the procedure on site. CONCLUSIONS: The proportion of Pacific Northwest American Indian and Alaska Native women in Indian Health Service and tribal clinics with abnormal Papanicolaou smears and the proportion who receive colposcopy are similar to those in other populations. The higher rate of cervical cancer mortality among American Indian and Alaska Native women could be due to failure to screen high-risk women. Cytologic screening rates, methods to improve adherence to colposcopy recommendations, and the contribution of other factors to the cause of cervical cancer mortality need to be characterized in this population.

Alaska↗