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Biomedical subjects

J E Miller

Publications and source records attributed to J E Miller.

At least 163 records · Page 9Linked to original sources

Prevention of the hyperlipidemic serum or LDL-induced cellular cholesterol ester accumulation by 22-hydroxycholesterol and its analogue.

Incubation of monkey arterial smooth muscle cells with hyperlipidemic serum or low-density lipoproteins (LDL) produces intracellular cholesterol ester accumulation. Increased esterification of free cholesterol within the cell may account for this effect. To examine such a possibility, oxygenated sterols were used to block cholesterol esterification. The increased esterification of free cholesterol by smooth muscle cells and human skin fibroblasts, through their exposure to hyperlipidemic lipoproteins, was inhibited by 22-hydroxycholesterol and its analogue, SC-32561 (22-hydroxy-25-fluorocholesterol). The hyperlipidemic LDL-stimulated elevation in the cholesterol ester content of the smooth muscle cells was also prevented by these sterols. This reduction in cellular cholesterol ester did not coincide with an increase in free cholesterol. 22-Hydroxycholesterol also blocked the stimulation of the esterification of cholesterol due to 25-hydroxycholesterol. In the absence of lipoproteins, 22-hydroxycholesterol and SC-32561 had a minor effect on the incorporation of [14C]oleate into cholesterol esters, and efficiently reduced sterol synthesis in fibroblasts and smooth muscle cells. 22-Hydroxycholesterol and SC-32561 had the additional effect of lowering the number of cell-surface LDL receptors to a greater extent than did hyperlipidemic LDL. The presence of 22-hydroxycholesterol did not alter the interaction of normal LDL with the receptor. Oxygenated sterols recovered in the cell represented 4-21% of the total sterol content. The level of intracellular oxygenated sterols was significantly reduced by the presence of lipoproteins in the culture media. Due to the multiple effects of the oxysterols, they were not effective as tools in determining the contribution of acyl-coenzyme A:cholesterol acyltransferase enzyme activity to the intracellular pool of cholesterol esters. These results indicated that 22-hydroxycholesterol and SC-32561 effectively blocked the hyperlipidemic LDL-stimulated increase in smooth muscle cell cholesterol ester content by lowering cholesterol esterification, reducing cholesterol synthesis and down-regulating LDL cell-surface receptors.

Animals↗

Esophageal impaction in BHE rats.

Spontaneous esophageal impaction was observed in 33 BHE rats, aged 6 to 26 months, from 157 rats which died or were killed when moribund due to spontaneous conditions. The clinical course lasted less than 48 hours and included weakness, excessive salivation, forward head motions, matting of chin and perioral hair with bedding material, followed by recovery or death. In some animals, the clinical episodes reoccurred. The esophagus was dilated (up to 7.0 mm) and impacted with bedding or food. The caudal half of the esophagus was affected more than the cranial half. The esophageal muscle was thin and pale at the site of impaction. Histologically, there was esophageal myodegeneration.

Animal Feed↗

Intracranial pressure and cerebral arterial pulsatile flow measurement in neonatal intraventricular hemorrhage.

We examined the clinical significance of noninvasive intracranial pressure measurements and pulsatility indices in 74 infants with confirmed IC-IVh. The intracranial pressure measurements were obtained using the applanation principle, and the pulsatility indices were calculated from the Doppler flow velocity tracings of the anterior cerebral artery. Fifty-three infants (71.6%) who died had a significantly lower birth weight and gestational age than those who survived. Survival rate decreased significantly with increased intracranial pressure (P less than 0.0002) and increased pulsatility indices (P less than 0.0001). We found no significant relationship between outcome and the size of IC-IVH demonstrated by CT scan. Birth weight, intracranial pressure measurements, and cerebral arterial pulsatile flow changes appear to be major prognostic indicators in neonatal IC-IVH.

Birth Weight↗

Homogeneous substrate-labeled fluorescent immunoassay for carbamazepine.

Carbamazepine is an anticonvulsant drug useful in the management of epilepsy. Because of the narrow therapeutic range, serum carbamazepine monitoring is useful for ensuring adequate drug therapy without toxicity. We report the development of a homogeneous substrate-labeled fluorescent immunoassay for carbamazepine in human serum. A carbamazepine fluorogenic reagent (FR) has been synthesized. Upon hydrolysis by beta-galactosidase, the nonfluorescent FR produces a fluorescent product. This enzymic hydrolysis sin inhibited when the FR binds with antibody against carbamazepine. The inhibition is relieved when carbamazepine competes with FR for available antibody binding sites. Thus, increasing levels of carbamazepine result in increasing levels of fluorescence that can be conveniently monitored with any conventional fluorometer. For low, medium, and high control sera (4, 12, and 16 micrograms carbamazepine/ml), the within-run coefficient of variation for the assay is 5.5%, 1.6%, and 2.9%, respectively, while the respective between-run coefficients of variation are 3.5%, 1.9%, and 2.3%. Fifty-three clinical serum samples were assayed by the SLFIA, gas chromatography (GC), high pressure liquid chromatography (HPLC), and an enzyme immunoassay method. The SLFIA method compares favorably with the HPLC technique (r - 0.97, slope = 1.10, y-intercept = 1.21), the enzyme immunoassay (r = 0.98, slope = 1.07, y-intercept = 0.82), and the GC method (r = 0.95, slope = 1.01, y-intercept = -0.03).

Antibodies↗

Radio-ligand immunoassay for human hemoglobin variants.

A quantitative method is described for the individual assay of human hemoglobin variants occurring singly or in mixture. The hemoglobin to be assayed is bound to specific antibody; the immune complex is attached to protein A-containing S. aureus and removed from the mixture. The hemoglobin thus isolated is quantified by its ability to bind radiolabeled haptoglobin. The technique is accurate and distinguishes among the 4 hemoglobins tested, namely Hb A, S, C and F. It has the advantage over conventional radioimmunoassay that a single probe, radiolabeled haptoglobin, is needed for the specific assay of any hemoglobin.

Genetic Variation↗

The thoracic outlet syndrome produced by costochondritis.

Thoracic outlet syndrome (TOS) is a rare condition in children. Compression of the neurovascular bundle as it passes from the neck through the thorax into the arm may be produced by numerous anatomic and structural abnormalities. This case represents compression produced by spasm of the pectoralis minor muscle originating from costochondritis.

Adolescent↗

Thiabendazole-resistant strains of Haemonchus and Ostertagia in California lambs.

Ten parasite-free experimental lambs were inoculated intraruminally with a mixed-larvae inoculum which contained approximately 5,000 Haemonchus contortus infective larvae. Five lambs were treated with thiabendazole (66 mg/kg of body weight) and 5 were untreated controls. All lambs were killed 35 days after inoculations were done, and parasites present were recovered. Reduction in numbers of recovered Haemonchus contortus (25.7%) and Ostertagia spp (26.8%) were not significant (P greater than 0.05).

Animals↗

Synthesis and biological activities of arachidonic and alpha- and beta-alkyl-substituted arachidonic acid derivatives.

In the male retired breeder rat, arachidonic acid 1a and 2,2-dimethylarachidonic acid 3a exhibited plasma platelet disaggregation as measured after 3 hr after the compounds were administered intragastrically at 15 and 13 mg/kg/rat mean effective dose (MED), respectively. The corresponding p-t-butylphenol ester of the acids showed a remarkable potentiation of platelet disaggregation. The MED for p-t-butylphenol ester of AA was 1.1 mg/kg/rat.

Alkylation↗

Cytological changes senescing WI-38 cells: a statistical analysis.

Changes in the cell, nuclear, nucleolar dry masses and areas were monitored simultaneously during in vitro senescence of WI-38 human fetal lung fibroblast cells, and the results were analyzed statistically. There was a two-step increase in all six parameters studied, following an initial decrease. The patterns of increase were strikingly similar for all six measures, i.e., an initial lag period was followed by a sharp increase, a plateau and a final, abrupt increase. In all cases, there was a strong correlation between corresponding area and dry mass measurements for each cell component. The dry mass/area ratio also increased as a function of in vitro aging and ultimately doubled in value. Weak intrapassage correlations between cell, nuclear and nucleolar dry masses indicated that there were passage to passage differences in the relative rates of dry mass increases which were not apparent over long periods of growth. The increases in all muclear and nucleolar areas were interdependent until the last doubling where they increased independently. The standard deviation for all six parameters increased as a function of in vitro senescence indicating that there was an increase in the heterogeneity of cells relative to these parameters.

Cell Division↗

Pancoast's tumor: irradiation or surgery?

Seventy-three patients with Pancoast's tumor treated at the University of Maryland Hospital between 1955 and 1978 were reviewed. Three were 34 squamous cell carcinomas, 13 undifferentiated, 10 adenocarcinomas, 4 mixed adenosquamous, 1 alveolar cell, and 11 undetermined. Twenty-nine patients received irradiation, with 7% survival at 3 years; 19 patients underwent preoperative irradiation followed by en bloc resection of chest wall, with 23% survival at 3 years; 5 patients underwent extended resection, with 60% survival at 3 years; and 18 patients underwent operation followed by irradiation, with 7% survival at 3 years. Retrospective staging of 42 patients undergoing operation indicated that 22 (52%) were inoperable. Prognosis was related to staging of the disease, the extent of local invasion, nodal involvement, cell type, and adequacy of operation.

Adult↗

Hypoplasia of the lumbar vertebral body simulating spondylolisthesis.

Fifty cases of spondylosis and spondylolisthesis were reviewed. In 9 of the 20 cases interpreted as Grade I spondylolisthesis at L5-S1, the sagittal diameter of L5 was shortened, creating a false impression of vertebral slippage. Such cases are felt to represent spondylolysis with hypoplasia of the vertebral body rather than true spondylolisthesis.

Diagnosis, Differential↗

Mandible height and syllable-final tenseness.

Mandible movements in the vowel-to-consonant transition manifest consistent differences between /t/ and /d/ in syllable final position. Both mandible position at its peak value near the articulatory release of the stop and velocity of its ascending movement in the transition are found to be apparently relevant to the tense/lax distinction, even though the reliability of these criteria for categorizing t/d data somewhat varies depending on the speaker. Some related characteristics of lingual movements and similar mandible characteristics for the k/g distinction are mentioned. The data were obtained by the computer-controlled X-ray microbeam system in cooperation with the University of Tokyo group.

Humans↗

Air pollutants and the admission rate of psychiatric patients.

The authors studied the correlation between mean daily levels of several air pollutants and the number of emergency room visits and inpatient admissions to a psychiatric hospital in St. Louis during one summer and fall. Nitrogen dioxide and carbon monoxide showed a positive correlation with emergency room visits by all patients, and nitrogen dioxide also had a positive correlation with inpatient admissions of subjects with diagnoses that were unknown or could not be specified as psychotic. Nitrogen monoxide showed a negative correlation with inpatient admissions during working days (but not during weekends and holidays) for all patients, as well as for those with diagnoses that were unknown or could not be specified as psychotic.

Air Pollutants↗

The use of chest wall muscle flaps to close bronchopleural fistulas: experience with 21 patients.

Nineteen patients with bronchopleural fistulas associated with tuberculosis and 2 patients with fistulas following resection for bronchiectasis underwent closure of the fistulas with pedicled flaps of chest wall muscle. The muscle grafting was combined with a limited thoracoplasty in 13 patients. The initial myoplasty produced prompt fistula closure in 15 patients and delayed closure in 2 others. A repeat myoplasty was successful in 2 patients in whom the initial myoplasty failed. Compared with other methods of treating bronchopleural fistulas used during the same period, muscle grafting carried a higher rate of successful fistula closure and a lower mortality rate.

Adult↗