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Biomedical subjects

T L Miller

Publications and source records attributed to T L Miller.

At least 91 records · Page 5Linked to original sources
PubMed1985

PCB-containing transformer fires: decontamination guidelines based on health considerations.

Realization that polychlorinated biphenyl-(PCB)-containing (askarel) transformer fires can produce toxic polychlorinated dibenzofuran (PCDF) and polychlorinated dibenzodioxin (PCDD) isomers has led to efforts to develop guidelines for cleanup of structures contaminated by soot from these fires. Two such fires have occurred in the United States in recent years, one in 1981 in Binghamton, N.Y., the other in 1983 in San Francisco. The phenomenon of PCB transformation to more toxic substances under conditions of uncontrolled combustion was studied in both locations, but much more extensively in New York. In terms of possible danger to human health, PCDFs comprise by far the most important PCB combustion products identified in the soot of both fires. PCDDs were not formed in sufficient quantity in either fire to constitute an important health hazard. The PCDF isomers of greatest health significance are the tetra-, penta-, and hexa- forms having all four lateral positions (2,3,7 and 8) chlorinated. Separate decontamination guidelines were established for each fire, based on different toxicity and exposure assumptions. One guideline was based on carcinogenic risk assessment of 2,3,7,8-TCDD and the other on experimental animal no-observed-effect level data for the same compound. More effort will be required to develop a generally accepted set of askarel fire decontamination guidelines.

California↗
PubMed1985

Temporomandibular joint clicking with nonreducing anterior displacement of the meniscus.

Patients who have temporomandibular joint (TMJ) clicking and pain are assumed to have an anterior displacement of the meniscus with reduction on opening of the jaw. On the basis of this assumption, these patients are treated nonsurgically with splint therapy. Of 301 TMJs examined, 108 (36%) produced clinically audible clicks on opening, closing, or both. Fluoroscopy and arthrotomography studies for 16 (15%) showed anteriorly displaced menisci without reduction. The mean age of this group was 32 years, with a range of 17-51 years. The duration of the patients' symptoms ranged from three months to eight years (mean 3.7 years). Bilateral degenerative joint disease was noted in 8/16 (50%). Operative findings in four patients suggested the cause of the clicking sound as a frictional impact between the degenerated surface of the condyle and the hypertrophied displaced meniscus. These observations demonstrate that an audible click may not imply a reduction of a displaced meniscus.

Adolescent↗
PubMed1985

Internal derangements of the temporomandibular joint: findings in the pediatric age group.

Findings in 31 pediatric patients with pain and dysfunction of the temporomandibular joint (TMJ) are reported. The average age was 14 years (range, 8-16) and the average duration of symptoms was 21.4 months (range, 3 mo.-5 yr.). Internal derangements were found in 29 patients (94%) and degenerative arthritis in 13 (42%). In 12 patients (39%), the problem could be traced to an injury to the jaw. Secondary condylar hypoplasia was associated with the meniscal abnormality in 3 patients (10%). Further awareness of internal derangements of the TMJ in the pediatric population should permit greater recognition of their etiology. It is important that treatment be initiated as soon as possible, not only to minimize the development of osseous disease in young adults but also to prevent facial growth deformities.

Adolescent↗
PubMed1985

Temporomandibular joint arthrography: comparison of morbidity with ionic and low osmolality contrast media.

We compared patient morbidity associated with temporomandibular joint (TMJ) arthrography using both meglumine/sodium diatrizoate (60%) and the new monoacidic dimer, Hexabrix, in a double-blind randomized clinical trial in 31 patients. Patients experienced maximal discomfort from TMJ arthrography with the initial joint filling and joint distension; this rapidly resolved over 10 minutes. Delayed exacerbation of pain is less than described for shoulder arthrography. The newer contrast media promise to decrease patient morbidity with arthrography.

Adult↗
PubMed1984

Poly(8-bromo-2'-deoxyadenylic acid): the syn/anti relationship.

The synthesis of a high-molecular-weight, putatively all-syn DNA analogue, poly(8-bromo-2'-deoxyadenylic acid), is described. The syn----anti transition was shown to be both salt and temperature dependent. Conditions were found which favored 'normal' Watson-Crick pairing and duplex formation with poly(dT).

Circular Dichroism↗
PubMed1984

Five antidepressant treatments in depressed patients. Effects on urinary serotonin and 5-hydroxyindoleacetic acid output.

The 24-hour urinary serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) outputs were repeatedly measured in 21 patients with major affective disorders after a minimum of three weeks free of drug treatments and at steady state during subsequent antidepressant treatments or during the second week after a series of electroconvulsive treatments (ECTs). The 5-HIAA outputs were more variable over time than the outputs of major catecholamine metabolites, previously studied by us. Patients with rapid mood cycles excreted large amounts of 5-HT. Lithium carbonate and ECTs reduced the outputs of 5-HT and 5-HIAA, respectively. Lithium carbonate also stabilized the output of 5-HT. No common effect of different antidepressant treatments on indole outputs was found.

Antidepressive Agents↗
PubMed1983

A homopolymer of the potent antitumor drug 2'-deoxy-5-fluorouridylate.

Poly(5-fluoro-2'-deoxyuridylic acid) was synthesized and its properties were compared with those of poly(dT) and poly(dU). It readily complexed with poly(dA). The 1:1 complex melted at about 20 degrees C lower than poly(dA) . poly(dT). A triple-stranded helix, poly(dA) . 2 poly(dF5U) was formed only in high salt (2.0 M NaCl).

Chemical Phenomena↗
PubMed1983

Stability of Methanobrevibacter smithii populations in the microbial flora excreted from the human large bowel.

Total anaerobic bacteria and Methanobrevibacter smithii populations were enumerated in fecal specimens from two individuals over 10- and 13-month periods. The ratio of M. smithii to total anaerobic count varied between the individuals, but it was a relatively constant proportion of the large-bowel microbial flora within each individual. Neither a barium enema examination of one subject nor a radical change in the diet of the other had any long-term effect on the methanogen populations.

Adult↗
PubMed1983

Oxidation of hydrogen and reduction of methanol to methane is the sole energy source for a methanogen isolated from human feces.

A methanogenic coccus isolated from human feces requires H2 and CH3OH for growth and uses H2 to reduce CH3OH to CH4. Growth does not occur with CH3OH alone. The organism does not grow or produce CH4 from acetate or methylamines without or with H2 or from H2 and CO2 or formate. In a complex medium. CO2 is required for formation of approximately 50% of cell carbon, whereas the methyl carbon from methanol is not incorporated into cell carbon.

Culture Media↗
PubMed1983

Interactions of microbial populations in cellulose fermentation.

Fermentation of cellulose in the rumen occurs through the interactions of many microbial species. The initial degradation of cellulose is caused by cellulase-producing organisms. The soluble hydrolysis products are used by both cellulolytic and noncellulolytic organisms to produce acetate, propionate, and butyrate and the important intermediates H2 and succinate. Interactions between species are necessary for the decarboxylation of succinate to propionate. H2 is used by methanogenic bacteria to reduce CO2 to CH4. The removal of H2 by methanogenesis increases the production of acetate from carbohydrates by several important cellulose- and carbohydrate-fermenting microbial species. Monensin and lasalocid appear to alter the overall fermentation by selecting for populations that produce relatively larger amounts of propionate and against populations that produce relatively larger amounts of acetate and H2. Cellulose fermentation in the human large intestine is compared with fermentation in the rumen.

Anaerobiosis↗
PubMed1982

Binding of crocetin to plasma albumin.

The binding of the carotenoid crocetin to human and bovine plasma albumin was studied using absorption and fluorescence techniques. Shifts in the absorption spectrum of crocetin, quenching of the albumin fluorescence, and competitive binding studies all provided information about the binding of crocetin to albumin. These studies suggest that crocetin binds to plasma albumin by occupying the free fatty acid binding sites. The binding constants for the first two binding sites are in the 10(5)-10(7) M-1 range and are an order of magnitude less than the values reported for other conjugated polyene fatty acids. The importance of this strong plasma albumin binding to the pharmacology of crocetin is discussed.

Animals↗
PubMed1982

Enumeration of Methanobrevibacter smithii in human feces.

A plating medium containing cephalothin and clindamycin was developed for enumeration and isolation of methanogens in human feces. Specimens from nine CH4-producing subjects had total anaerobe counts of 1-8 x 1011/g dry weight. Methanogen counts on the antibiotic medium ranged from 0.001 - 12.6% of the total anaerobe count. There was no correlation between age, sex or percent dry fecal weight and the ratio of methanogens to total counts. Specimens from eight non-CH4-producing individuals contained bacteria that yielded nonmethanogenic colonies on the antibiotic medium. The means +/- SD of the logarithm of the total counts per gram dry weight were 11.4 /+- 0.29 and 11.38 +/- 0.44 for the positive and negative groups respectively. Values for the antibiotic-resistant flora were 8.8 /+- 1.13 and 7.78 /+- 1.08 respectively. Methanogens were isolated from the most dilute inoculum of each specimen from CH4-producing subjects. All isolates were morphologically, physiologically, and immunologically identical to Methanobrevibacter smithii. Growth of methanogens in media that were essentially extracts of CH4-negative feces suggested that no nutrients were lacking or inhibitors present in intestinal contents that prevent the growth of methanogens in these individuals.

Adult↗
PubMed1982

Isolation of Methanobrevibacter smithii from human feces.

Fecal specimens from nine adults were examined for the presence of methanogenic bacteria. Enrichment cultures of five specimens produced methane in 5 days. Of these five specimens, three were tested and produced methane during a short-term incubation. Four specimens did not produce methane in either short-term incubation or in enrichment culture. Each methanogenic culture contained methanogens similar in morphology to organisms of the genus Methanobrevibacter and showed factor-420 fluorescence by fluorescence microscopy. Pure cultures were obtained from four of the five methanogenic enrichment cultures. Each isolate grew and formed methane from either H2-CO2 or formate, but growth obtained with formate was poor. None of the isolates used acetate, methanol, or trimethylamine. All isolates grew in the presence of bile salts. In immunological studies, each isolate was closely related to the type strain of Methanobrevibacter smithii, a finding consistent with the physiological and morphological similarities between the isolates and the type strain.

Adult↗
PubMed1982

Cognitive tempo and cognitive level relationships among mentally retarded children.

The purpose of this investigation was to ascertain predictive relationships between and within cognitive tempo and cognitive level characteristics of 33 moderately retarded junior high school children. The Matching Familiar Figures Test was used to establish cognitive tempo characteristics and the Essential Math and Language Skills Inventory was used to determine cognitive level characteristics. A multiple regression analysis indicated no significant predictive relationship from elements of cognitive tempo to elements of cognitive level. Elements of cognitive level, however, could predict elements of cognitive tempo. Implications for future research were discussed. Cross-validation on a larger sample is required.

Adolescent↗
PubMed1981

Fermentation by the human large intestine microbial community in an in vitro semicontinuous culture system.

A semicontinuous culture of the microbial community of the human large intestine that was maintained over 81 days is described. The initial inoculum was feces, and about 200 ml of nutrient suspension was fed to 500 ml of fermentor contents once or twice daily. The nutrient suspension contained comminuted fibrous food, sodium deoxycholate, urea, acid-hydrolyzed casein, vitamins, and salts. The fermentation was monitored, and the major products were acetate, propionate, butyrate, methane, hydrogen, and carbon dioxide. The concentration of anaerobic bacteria was 2 X 10(9) per ml of culture contents and was 100 times that of fecal coliforms. When the nutrient suspension contained lettuce, celery, carrots, and unsweetened applesauce, the predominant nonsporeforming anaerobes isolated were Bacteroides species. When carrots and applesauce were omitted, the predominant nonsporeforming isolates were Fusobacterium species. On both diets, clostridia were isolated that resembled Clostridium clostridiiforme. The fermentation and bacteriological analyses indicated that the in vitro ecosystem appears to be a reasonable facsimile of the large intestine ecosystem.

Bacteria↗