Biomedical subjects
Publications and source records attributed to E D Brown.
The syntheses of five compounds isomeric with the potent luteolytic agent cloprostenol are described. These are the trans-delta 5, cis and trans-delta 4, cis-delta 6 (methyl ester) and cis-delta 13 analogues. The cis-delta 4 isomer is as potent as cloprostenol as a luteolytic agent in hamsters but the others are markedly less so.
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Groups of 30 turkeys were vaccinated by the drinking water route against fowl cholera with varying doses of the low virulence, CU strain, of Pasteurella mulocida. One group (heavy dose) received 1.2 x 107, another (medium dose) 1.5 x 105, and a third (light dose) 1.0 x 103 bacteria per ml. of drinking water. Two (6.7%) vaccine induced cholera deaths occurred in the heavy dose group. No deaths resulted in the other groups. Maximum serum antibody titers per group were; light dose 1:32, medium dose 1:128, and heavy dose 1:256. Three weeks after vaccination all turkeys were challenged with a large dose of virulent P. multocida (P-1059). Mortalities resulting from the challenge were 100% in the light group, 23% in the medium group, 4% in the heavy group, and 100% in the unvaccinated controls.
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An extremely high concentration of zinc in the plasma (hyperzincemia) was found in five out of seven members of one family and in two out of three second generation indiviuals, an indication that the condition is heritable. The excess zinc in the plasma appears to be bound to serum proteins, with no apparent clinical symptoms or abnormalities.
The experiments reported here were designed to determine if the low plasma vitamin A levels observed in zinc deficient rats are reversible as well as to examine the time required for any response. In experiment 1, rats previously zinc deficient were repleted for 6 days with a zinc sufficient diet, fed either ad libitum, or pair-fed the amount consumed by a zinc deficient group. After repletion, plasma vitamin A concentration for the zinc sufficient group returned to within normal range while the pair-fed group had a plasma vitamin A concentration intermediate between the zinc sufficient ad libitum and zinc deficient groups. The zinc sufficient ad libitum group had a lower concentration but higher total liver content of vitamin A than the other two groups. In experiment 2, the response of zinc deficient rats to intraperitoneal zinc repletion was examined daily for 7 days. There was a 3 day lag period before plasma vitamin A began to increase significantly following zinc treatment. By the fifth day, plasma vitamin A concentration increased to within the normal range. The data suggest that adequate food intake as well as zinc appears necessary to totally reverse low plasma vitamin A concentrations in zinc deficiency. Possible mechanisms are discussed.
The purpose of these experiments was to further elucidate the effect of the trace element, zinc, on vitamin A metabolism. Three experiments were conducted at two different locations using different sources of animals. A total of 95 rats were used; 71 specific pathogen free and 24 germfree. The results indicate that plasma vitamin A is depressed in zinc deficient animals or animals severely restricted in food and growth. Liver stores of vitamin A were adequate in both groups. Thus, the normal mechanism for maintaining plasma vitamin A appears to be altered by either zinc deficiency and/or severe food and growth restriction.
Sample hospital meals for breakfast and the noon and evening meals for regular, ovo-lacto-vegetarian, and renal diets were collected for seven consecutive days. The daily zinc content of each diet was determined, using atomic absorption spectrophotometric analysis and by calculation, using the USDA provisional tables on the zinc content of individual foods. The data indicated that the provisional tables provide a reasonable estimation of zinc content of regular or renal diets with errors approximately 10%. However, a 35% overestimation occurred for vegetarian diets. A major cause of error between assayed and calculated values was probably due to substituting items not included in the tables. The mean zinc content for the regular diet, as offered, was 97% of the adult recommended allowance for zinc, while the vegetarian diet provided 81% of the allowance. The average renal diet contained 49% of the allowance. Certain types of vegetarian and low-protein diets may be inadequate in total and/or available zinc. Also important in evaluating hospital diets for adequacy of zinc are the actual intake and the condition of the patient.
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Two experiments were conducted to examine the effect of zinc deficiency on glucose tolerance, and on blood and pancreatic insulin concentrations. In the first study, no significant differences in blood glucose or plasma insulin levels were noted between pair-weighted zinc deficient and zinc sufficient rats after an oral glucose load. In the second experiment, the concentration of pancreatic insulin in pair-fed zinc sufficient rats did not differ significantly from that of zinc deficient rats. However, a zinc deficient group fed ad libitum had significantly lower pancreatic insulin levels, suggesting that food restriction may cause increased pancreatic insulin. Thus, zinc deficiency per se had no apparent effect on oral glucose tolerance or pancreatic insulin concentrations.
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The authors reviewed their 2 1/2-year experience with a magnetic resonance (MR) imaging protocol for a 1.5-T MR imager that included T2-weighted fat-suppressed spin-echo, T1-weighted breath-hold gradient-echo, and serial dynamic gadolinium-enhanced T1-weighted gradient-echo imaging to identify histologic types of malignant liver lesions more apparent on T1- than on T2-weighted images. MR images of 212 consecutive patients with malignant liver lesions were reviewed. T2-weighted, T1-weighted, and dynamic contrast-enhanced T1-weighted images were examined separately in a blinded fashion. Seven patients demonstrated liver lesions (lymphoma [two patients] and carcinoid, hepatocellular carcinoma, colon adenocarcinoma, transitional cell carcinoma, and melanoma [one patient each]) on T1-weighted images that were inconspicuous on T2-weighted images. In all cases, the lesions were most conspicuous on T1-weighted images obtained immediately after administration of contrast agent. Histologic confirmation was present for all seven patients. The consistent feature among these lesions was that they were hypovascular, due either to a fibrous stroma or to dense monoclonal cellularity. These results suggest that in some patients with hypovascular primary neoplasms, the lesions may be identified only on T1-weighted images, and that immediate postcontrast T1-weighted images are of particular value in demonstrating lesions.
Three rapid T1-weighted gradient-echo techniques for imaging of the liver were compared: fast low-angle shot (FLASH) and section-selective (SSTF) and non-section-selective (NSTF) inversion-recovery TurboFLASH. Ten healthy volunteers were imaged at 1.5 T, with breath-hold images acquired in the transaxial and coronal planes and non-breath-hold images in the transaxial plane. Breath-hold images were evaluated quantitatively and qualitatively, and non-breath-hold images were evaluated qualitatively. FLASH images had significantly higher (P < .001) spleen-liver signal difference-to-noise ratios (SD/Ns) than NSTF and SSTF images. Liver signal-to-noise ratios (S/Ns) were significantly higher (P < .001) on FLASH images than on NSTF and SSTF images. With breath hold, FLASH images were rated as having the highest quality in the axial plane, followed by NSTF and SSTF images. In the coronal plane, NSTF images were rated as having the highest quality. For images acquired during patient respiration, NSTF images had the highest quality and showed the least degradation. The results suggest that FLASH images have the highest SD/N and S/N for liver imaging and have the highest quality in the axial plane. In patients who cannot suspend respiration. NSTF images may be least affected by breathing artifact and provide reasonable image quality.
The purpose of the study was to define the magnetic resonance (MR) imaging appearance of adrenocortical carcinoma (ACC) with current MR techniques. Eight patients with ACC underwent high-field-strength MR imaging with the following sequences: axial T1-weighted gradient echo, fat-suppressed T1-weighted spin echo, fat-suppressed T2-weighted spin echo, and gadolinium-enhanced T1-weighted gradient echo and fat-suppressed T1-weighted spin echo. Postcontrast images were also acquired in the sagittal (six patients) and coronal (three patients) planes. Out-of-phase gradient-echo images were obtained in two patients. Lesion morphology, signal intensity features, and presence of metastatic disease were retrospectively evaluated. MR imaging features of ACC included internal hemorrhage (seven of eight patients), central necrosis (seven of eight), and peripheral enhancing nodules (seven of eight). Out-of-phase images in two of two patients demonstrated signal loss compared with in-phase images, which may be a common feature of these tumors. Liver metastases were present in four patients. Consistent MR features of ACC are identified.
Suspected pelvic endometriosis was prospectively evaluated in 31 women with T1- and T2-weighted conventional spin-echo (CSE) magnetic resonance imaging alone and in combination with T1-weighted fat-suppressed (T1FS) and gadolinium-enhanced T1FS (Gd-T1FS) spin-echo techniques. Images were grouped for interpretation and comparison as follows: (a) CSE alone, (b) CSE/T1FS, and (c) CSE/T1FS/Gd-T1FS. All patients underwent surgery within 3 months of imaging, and 21 patients were found to have endometriosis: 59 endometriomas (26 large and 33 small) and 51 sites of implants were seen. With CSE images, 23 large and six small endometriomas were detected. With CSE/T1FS images, 25 large and 14 small endometriomas were identified. With CSE/T1FS/Gd-T1FS images, 24 large and 14 small endometriomas were detected and ill-defined areas of enhancement were noted in 22 sites throughout the pelvis. These corresponded to endometriotic implants seen at surgery in 14 sites. The sensitivity, specificity, and accuracy, respectively, for the detection of endometriosis were 76%, 60%, and 71% for CSE, 86%, 50%, and 74% for CSE/T1FS, and 81%, 50%, and 71% for CSE/T1FS/Gd-T1FS images. No significant differences (P > .1) between image combinations for correctly identifying patients with and without endometriosis were seen. The difference in sensitivity between CSE and CSE/T1FS and between CSE and CSE/T1FS/Gd-T1FS images for detecting small endometriomas was significant (P = .03).
This study evaluates the MR appearance of the kidney in diffuse renal parenchymal diseases, using precontrast, and immediate and delayed postgadolinium chelate (Gd), spoiled gradient echo (SGE), and pre- and post-Gd, T1-weighted, fat-suppressed spin-echo MR images to determine if characteristic findings exist for various types of renal disease. One hundred twenty-one patients with renal disease underwent MRI. Underlying diagnoses included: (a) glomerular disease (GD), (b) tubulointerstitial disease (TID), (c) microvascular disease (MVD), (d) ischemic nephropathy (INP), (e) obstructive nephropathy (ON), (f) infectious renal disease (IRD), (g) sickle cell disease (SCD), (h) renal cortical necrosis (CN), and (i) renal insufficiency of unknown etiology (UE). MR examinations of 22 patients with normal kidneys (NK) were evaluated as a control group. The presence of corticomedullary differentiation (CMD) demonstrated strong inverse correlation with serum creatinine concentration (SCr) (r = -.568, P < .001). Mean thickness of the renal cortex was 8.4 and 7.8 mm in patients with NK and Gd, respectively. The mean cortical thickness in patients with MVD, TID/Chemo, INP, and ON was 5.2, 5.6, 5.5, and 4.3 mm, respectively, significantly thinner than the renal cortex in the NK and GD groups (P < .01). Irregularity of the renal cortex was more frequent in MVD (60.9%), IRD (62.5%), ON (55.6%), and TID/other (53.8%) than in GD (3.8%) and NK (0%) (P < .01). Diffuse high SI of the entire medulla on delayed postcontrast images was observed in 25 (20.7%) of the patients with renal disease and none of the NK group. Although no pathognomonic features were found, certain findings were observed that may correlate with the etiology of the kidney disease and, therefore, assist in the differential diagnosis of renal parenchymal disease.
BACKGROUND: This study evaluates the ability of MRI to stage transitional cell carcinoma of the upper urinary tract. METHODS: Nine patients who had transitional cell carcinoma of the upper urinary tract detected by other imaging modalities underwent MRI examination at 1.5 T. Imaging included pre- and postgadolinium-DTPA T1-weighted images (9 patients) pre- and postgadolinium chelate T1-weighted fat-suppressed spin echo (7 patients). Postcontrast images were acquired prior to the presence of gadolinium within the collecting system (< 2 min postcontrast), intermediate (2.5-8 min), and late (> 10 min) postcontrast. Images were prospectively interpreted and lesion staging was determined. Correlation with histopathology was obtained in all cases. RESULTS: Transitional cell cancers were demonstrated in 9/9 patients, and tumors ranged in size from 2 to 8 cm (mean = 3.8 cm) in one dimension. Correct tumor staging was performed in 8/9 patients. The staging error in one case occurred because direct tumor extension into the renal parenchyma was not detected. CONCLUSIONS: The results of this preliminary study show that MRI stages transitional cell cancers relatively well; however, MRI is not able to detect superficial invasion of renal parenchyma.