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Biomedical subjects

H D Fawcett

Publications and source records attributed to H D Fawcett.

At least 19 recordsLinked to original sources
PubMed1992

Bone mineral density of the lumbar vertebrae in children and adolescents with insulin-dependent diabetes mellitus.

To test the hypothesis that bone mineral density (BMD) is lower in children with insulin-dependent diabetes mellitus (IDDM), we measured BMD of the lumbar vertebrae (L-2 to L-4) by dual-photon absorptiometry in 31 boys and 25 girls, mean age 12.3 years, with IDDM of varying clinical duration (range 0.1 to 14.8 years). Mean standard deviation scores (z scores) were determined for L-2-L-4 BMD, weight, height, weight percentile, and weight-adjusted L-2-L-4 BMD index (L-2-L-4 BMD/weight), with reference data from a previously described white, nondiabetic, age-matched control group (n = 221). Compared with nondiabetic control subjects, male patients with short-term IDDM and all female patients with IDDM did not have significantly different L-2-L-4 BMD, weight, weight percentile, height, or BMD index. Boys with IDDM longer than 1 year had significantly lower weight, weight percentile, and height than did age-matched control subjects. When L-2-L-4 BMD of boys with long-term diabetes was corrected for weight, the L-2-L-4 BMD index was significantly greater than that of control subjects, indicating that weight was disproportionately lower than BMD. There were no significant linear correlations between metabolic control and L-2-L-4 BMD. When L-2-L-4 BMD was adjusted for differences in body weight, spinal BMD values in children with IDDM were not lower than in control subjects. These findings indicate that in children with IDDM, as in previously studied nondiabetic youths, body weight and spinal BMD are highly correlated; although BMD is reduced in some children with diabetes, the reduction parallels reductions in growth, and may simply reflect a normal response of the skeleton to a lower weight-bearing load.

Absorptiometry, Photon↗
PubMed1991

Spinal bone mineral density in 335 normal and obese children and adolescents: evidence for ethnic and sex differences.

Spinal bone mineral density (BMD) and anthropometric measures were studied in 312 nonobese and 23 obese black, white and Hispanic children and adolescents age 5.00-18.99 years. In adolescents BMD correlated with age, weight, height, fat-free density, body mass index, and midarm circumference. Utilizing the entire group of 312 nonobese subjects, mean Z scores were calculated for comparison versus reference subgroups for bone mineral density index (BMDI, BMD/weight). BMDI was greater for black than for white and Hispanic children and adolescents across all ages studied. Female adolescents accumulated spinal mineral more rapidly than male adolescents. Black males had greater mineral than white and Hispanic males. Differences in BMDI between subgroups could not be explained by differences in body weight or spinal vertebral size. BMDI proved a more sensitive measure for comparing subgroups than did BMD. The study provides normative data and a quantitative methodology for analyzing differences in spinal mineral between groups of children and adolescents.

Adolescent↗
PubMed1990

Spinal bone mineral density in children aged 5.00 through 11.99 years.

Lumbar spine (L-2, L-3, L-4) bone mineral density was measured in 184 healthy boys and girls aged 5.00 through 11.99 years by dual photon absorptiometry. Weight, height, age, triceps skinfold thickness, and midarm circumference were also measured. Weight, height, and age were highly correlated with bone mineral density. In the population studied, a quadratic regression equation using body weight as the independent variable best described bone mineral density: bone mineral density = 0.3209 + [0.0168 (weight)] - [0.0001 (weight2)].

Body Height↗
PubMed1989

Uptake of 131I-metaiodobenzylguanidine by 6-23 rat medullary thyroid carcinoma.

Uptake of 131iodine-metaiodobenzylguanidine (131I-MIBG) by 6-23 rat medullary thyroid carcinoma (MTC), was studied in vitro and in vivo. In vitro, there was an 8-fold increase in 131I uptake by 6-23 cells when labeled with 131I-MIBG (131I 24 +/- 15 cpm/10(6) cells, 131I-MIBG 196 +/- 9 cpm/10(6) cells). MIBG uptake in vitro was the same at 4 degrees C and 37 degrees C. In contrast, 131I-MIBG uptake by PC-12 rat pheochromocytoma cells were 200 times greater (131I-MIBG 42,412 +/- 6,755 cpm/10(6) cells). 131I-MIBG uptake by rat MTC cells in vitro were of a comparable magnitude to the uptake of 131I-MIBG by rat ileal enterochromaffin cells (RIE-1) and mouse colon cancer cells (MC-26). In vivo, uptake of 131I-MIBG by 6-23 MTC tumor was considerably less than in the normal tissues (muscle, liver, spleen, kidney, adrenal and thyroid). Gamma camera studies of 131I-MIBG uptake by 6-23 MTC tumors growing in Wag-Rij rats were only transiently positive in 1 out of 4 rats studied. We conclude that 131I-MIBG is poorly taken up by rat medullary thyroid carcinoma and is an unpredictable marker for localization of rat MTC.

3-Iodobenzylguanidine↗
PubMed1989

SPECT versus planar liver scintigraphy: is SPECT worth it?

Five hundred three planar and SPECT hepatic studies were reviewed separately by two experienced observers looking for focal disease. An equivocal reading meant referral to ultrasound or computed tomography (US/CT). The increase in correct readings and decrease in US/CT referrals per 100 positive and per 100 negative SPECT readings were calculated, then the increase in correct readings and decrease in US/CT referrals for various positive rates of liver involvement determined. At our institution, the overall positive rate is approximately 13% yielding 1.1 and 0.83 more correct readings and 1.8 and 2.0 fewer US/CT referrals per 100 cases for each reader, respectively; a marginal benefit for SPECT over planar scintigraphy.

Diagnosis, Differential↗
PubMed1988

How useful is gastroesophageal reflux scintigraphy in suspected childhood aspiration?

It has been suggested that gastroesophageal reflux scintigraphy (GRS) might be useful in assisting one in determining therapy for patients suspected of aspirating or becoming apneic secondary to gastroesophageal reflux. This, however, has not been our experience and in reviewing 23 patients with recurrent pneumonia and/or apnea who had GRS, we were able to detect aspiration in only one. This was especially significant since 13 (59%) of these patients had demonstrable reflux, and of these, eight were treated successfully for suspected aspiration even though none was demonstrated isotopically. To be sure, the demonstration of pulmonary aspiration with GRS had little influence on patient selection and response to therapy. For this reason we feel there is little justification in depending on the GRS for the specific purpose of trying to document pulmonary aspiration in infants and children who are refluxing.

Apnea↗
PubMed1988

Gastroesophageal reflux: how much imaging is required?

The authors present a protocol for the selection of imaging studies for infants suspected of gastroesophageal reflux. In most cases, only a single imaging procedure is required. Three groups of patients are considered: those suspected of an esophageal or postgastric obstruction who require a barium GI series; those who appear to have reflux and a possible gastric obstruction in whom sonographic study of the gastric outlet is advised; and those suspected of aspirating in whom the possibility of reflux is studied by scintigraphy. Esophagoscopy and other studies are reserved for those refractory to therapy.

Gastroesophageal Reflux↗
PubMed1988

Renal transplant dysfunction: MR evaluation.

The results of 45 MR examinations were prospectively compared with the clinical course and biopsy results in 38 renal transplant patients to determine the role of MR in evaluating allograft dysfunction. Twenty-six patients underwent allograft biopsy. In eight patients in whom the biopsy was performed more than 48 hr after MR examination and in 19 patients who did not have a biopsy, the subsequent clinical course was sufficiently diagnostic to determine the specific cause of the transplant dysfunction. Corticomedullary differentiation, graded from 0 to 3, was not helpful in separating rejection (n = 20) from acute tubular necrosis (n = 9), drug toxicity (n = 7), pyelonephritis (n = 2), or normal grafts (n = 7) because of overlap between groups (sensitivity =; 60%, specificity = 60%). In the six patients with two or more MR studies, serial changes in corticomedullary differentiation were not consistent and could not be used to diagnose rejection. When any abnormality of allograft sinus fat, size or shape, or corticomedullary differentiation was considered, the sensitivity for the diagnosis of rejection approached 80%; however, specificity was low (48%). We conclude that MR imaging is not sufficiently accurate to replace transplant biopsy and therefore has a limited role in the evaluation of transplant dysfunction.

Cyclosporins↗
PubMed1987

Left ventricular aneurysm in short axis: a comparison of magnetic resonance, ultrasound and thallium-201 SPECT images.

Short axis magnetic resonance images of a left ventricular aneurysm were compared to similar views obtained by echocardiography and by thallium-201 single photon emission computed tomography. Images of the dyskinetic left ventricular apex and the contractile left ventricular base were analyzed and compared. Unlike the previously reported orthogonal plane magnetic resonance images, short axis imaging provided representative and quantitative information in views comparable to those obtained by standard noninvasive imaging techniques. These data indicate that short axis magnetic resonance imaging is capable of identifying and sizing the aneurysmal and the residual segments of the left ventricle. The findings may be of prognostic value in patients with left ventricular aneurysm.

Coronary Aneurysm↗
PubMed1987

Hyperthyroidism and the single lobe.

A practical approach to the hyperthyroid patient with a single lobe visualized on thyroid scintigraphy, and its impact on therapy is discussed. An illustrative case is also presented.

Adenoma↗
PubMed1987

Indium-111 chloride imaging with ununited fractures.

Twenty patients with ununited fractures and a suspicion of infection had In-111 chloride imaging. Surgically obtained cultures were positive for infection in 12 and negative in eight patients. In-111 chloride images were positive in all 12 patients with infection but also were positive in six of the patients with negative cultures. It is not possible to differentiate infected from noninfected ununited fractures by In-111 chloride imaging.

Fractures, Ununited↗
PubMed1986

Comparison of two methods of labeling proteins with 111In.

DTPA N-hydroxysuccinimide pentaester (DHSE) can be used as an alternative to bicyclic anhydride for coupling proteins with DTPA. However, in-vitro analysis of labeled proteins coupled with DHSE compared to bicyclic anhydride showed more high molecular weight product and less serum stability. We studied the magnitude of these differences in vivo by coupling HSA and IgG with DTPA using both methods, labeling with 111In, and analyzing the biodistribution in mice. The results of this analysis showed comparable activity in the liver, kidneys and blood.

Indicators and Reagents↗
PubMed1986

Indium-111 leukocyte scanning. False-negative study in a renal abscess.

A 33-year-old man had clinical features of a right renal abscess. Results of excretory urography and ultrasonography showed a focal complex mass lesion in the right kidney. An In-111 leukocyte scan failed to detect the right renal abscess, which later was aspirated under CT guidance and explored surgically. The role of In-111 leukocyte imaging in the detection of intra-abdominal abscesses, with limitations of the procedure, is discussed.

Abscess↗