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Biomedical subjects

R E Miller

Publications and source records attributed to R E Miller.

At least 109 records · Page 6Linked to original sources
PubMed1990

Beta-globin chain hemoglobin polymorphism and hemoglobin stability in black rhinoceroses (Diceros bicornis).

To evaluate the syndrome of acute intravascular hemolytic anemia in black rhinoceroses (Diceros bicornis), the hemoglobin of this species was evaluated by use of isopropanol- and heat-stability tests and was further characterized by electrophoretic studies. Samples were obtained from 22 apparently healthy captive North American black rhinoceroses, though 3 of the study animals had survived previous hemolytic events, and 3 others were parents of 3 offspring that had suffered hemolysis. The eastern African (Diceros bicornis michaeli) and the southern African subspecies (D b minor) were represented. Comparative samples were also obtained from 2 white (Ceratotherium simum) and 1 Indian (Rhinoceros unicornis) rhinoceroses. The hemoglobin of all 3 species appeared stable when tested by use of the heat and isopropanol methods. Thus, an unstable hemoglobin does not appear to be involved in the hemolytic crises of captive black rhinoceroses. Black rhinoceros hemoglobin had a striking polymorphism. Thirteen of the samples from black rhinoceroses had a single hemoglobin band, based on results of alkaline electrophoresis. Nine had, in addition to this major band, a slow (more cathodic) minor band that comprised about 10% of the total hemoglobin. Further studies indicated that the major band and the slower minor band may contain globin chains analogous to human beta- and delta-chains respectively; these bands have been tentatively designated B and C. Phenotypes B and BC are common, in a ratio of 4:3. A genetic mechanism is proposed that assumes beta b and beta c gene loci and that beta c-locus-expressed (beta c+) and beta c-locus-inhibited (beta c degrees) are common alleles for the beta c-locus.(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia, Hemolytic↗
PubMed1989

Idiopathic epilepsy in three gaur (Bos gaurus).

Idiopathic epilepsy was diagnosed in 3 gaur in a zoologic park collection during a 3-year period. Seizures were characterized by tonic rigidity of all limbs. Results of serum biochemical analysis, CBC, blood lead analysis, CSF analysis, and necropsy were within normal limits in all gaur. The role of heredity in development of seizures in these gaur is unclear because of limited founder stock of gaur in North America.

Animals↗
PubMed1989

Percutaneous endoscopic gastrostomy. Results in 316 patients and review of literature.

Three hundred and sixteen patients underwent 330 percutaneous endoscopic gastrostomies (PEG) of the Russell or introducer type. Seventy-five percent of the patients had neurological conditions that precluded swallowing. Absolute contraindications included pharyngeal or esophageal obstruction, uncorrectable coagulopathy or inability to perform endoscopy. The mean age of the patients was 75 years. The procedure took an average of 17.5 min to perform. PEG could not be performed in 14 patients (4.1%). Major complications occurred in 2.1% of patients, including 5 who developed peritonitis. No infections occurred at the gastrostomy tube site. The procedure mortality was 0.6%. PEG never required general anesthesia. For patients with long-term swallowing abnormalities, PEG is preferred to nasogastric feeding, operative gastrostomy or parenteral alimentation.

Aged↗
PubMed1989

Characteristics of psychomotor performance and time cognition in moderately obese patients.

To clarify adherence of obese subjects to external food-relevant stimuli, we examined time cognition and psychomotor functioning of the obese under noneating conditions in the present study. Matched on the basis of age, sex, height, intelligence quotient and education, 13 moderately, but adult-onset obese (mean obesity index +/- SEM, 53.9 +/- 5.0% by Matsuki's method) and 13 normal weight subjects (-6.3 +/- 2.3%) were tested. Obese females were slower than normal weight control subjects in alternate tapping of two metal plates (p less than 0.01) and in transfer of a dowel (p less than 0.05). Normal subjects were slightly but significantly (p less than 0.05) more efficient in a self-cued traverse movement test, whereas the obese subjects were very much less efficient in the self-cued than in the externally-cued test. These findings suggest that evaluation of deficits of the obese must consider other factors in addition to simple physical slowness due to fattening. In time cognition tests, cognitive levels of the obese were more accurate when initiated by time cues than when they were self-cued (p less than 0.01). The results indicate that obese (even after adult-onset) may exhibit impairment in internal time cognition when deprived of external modulating time cues.

Adult↗
PubMed1989

Behavioural consequences of hypertension: effects of age and type of antihypertensive agent.

In order to investigate the effects on behaviour of hypertension, age, and the types of antihypertensive agents, we have conducted a retrospective analysis in 100 hypertensive patients receiving chronic treatment in our Hypertension Clinic. A group of 80 normotensive subjects, matched for age, were included in the study. Half of the hypertensive patients were under the age of 50 (young group) and half were over the age of 50 yrs (old group). The antihypertensive agents had not been administered according to any specific protocol, but represented the choice of the individual clinicians treating the patients in the clinic. All patients had received treatment for at least one year, and usually for two years. The behavioural tests performed were designed to measure sensory-perceptive ability, cognitive ability and psychomotor function and were those employed and described in our previous studies. The results achieved were varied, but indicated that older age was associated with an impairment in performance as was blood pressure. Test performances in the young hypertensives were similar to those achieved by older normotensives. These results were more prominent in cognitive and psychomotor functions than in the sensory-perceptive tests. The antihypertensive drugs used also affected these results; the worst behavioural performances tended to be in patients receiving the central nervous system agonists (methyl-dopa and clonidine) and better performances in patients receiving beta-blockers alone when compared with the other groups. Surprisingly, patients receiving diuretics showed poorer performance levels, but these were better in patients who received a beta-blocker in combination with their diuretic.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1988

Cloning, nucleotide sequence, and potential regulatory elements of the glutamine synthetase gene from murine 3T3-L1 adipocytes.

Glutamine synthetase [L-glutamate:ammonia ligase (ADP-forming); EC 6.3.1.2] specific activity, cellular content, mRNA abundance, and gene transcription rate increase by greater than 100-fold during adipocyte differentiation of 3T3-L1 cells. In 3T3-L1 adipocytes dexamethasone increases, whereas insulin as well as N6,O2'-dibutyryladenosine 3',5'-cyclic monophosphate decrease, glutamine synthetase gene expression. We analyzed the nucleotide sequence of a 1.9-kilobase Sal I-EcoRI restriction fragment from a 3T3-L1 glutamine synthetase genomic clone. This genomic fragment is composed of 1851 base pairs (bp) and includes the first exon and 1029 bp of the 5' flanking sequence. The 600 bp at the 3' end of the 1.9-kb Sal I-EcoRI restriction fragment constitute an open reading frame. We identified the transcription start site at a location 222 bp upstream of the glutamine synthetase coding sequences. The 5' flanking region of the gene encompasses several potential regulatory elements including TATA and CAAT sequences and a 40-bp poly(dT-dG).poly(dC-dA) putative enhancer element. Potential hormone and fat-specific regulatory elements are also located upstream of the transcription start site; they include glucocorticoid and cAMP response elements and fat-specific elements. These potential regulatory elements could account for the differentiation-associated changes and hormone-mediated changes seen in glutamine synthetase gene transcription and mRNA abundance.

Adipose Tissue↗
PubMed1988

Vitamin E in captive and wild black rhinoceros (Diceros bicornis).

The mean plasma level of alpha-tocopherol (vitamin E) measured in 31 free-ranging black rhinoceros (Diceros bicornis) was significantly higher (P less than 0.001) than that in 11 captive animals (means +/- SE = 0.77 +/- 0.05 and 0.18 +/- 0.03 micrograms/ml, respectively). Vitamin E status may influence the health of captive black rhinoceros; in particular, it may be linked to hemolytic anemia commonly observed in these animals in captivity.

Anemia, Hemolytic↗
PubMed1988

Integrated pathology reporting, indexing, and retrieval system using natural language diagnoses.

Pathology computer systems are making increasing use of natural language diagnoses. The Johns Hopkins Medical Institutions integrated pathology reporting system, a commercial product with extensive, locally added enhancements, covers all information management functions within autopsy and surgical pathology divisions and has on-line linkages to clinical laboratory reports and the medical library's Mini-MEDLINE system. All diagnoses are written in natural language, using a word processor and spelling checker. A security system with personal passwords and different levels of access for different staff members allows reports to be signed out with an electronic signature. The system produces financial reports, overdue case reports, and Boolean searches of the database. Our experience with 128,790 consecutively entered pathology reports suggests that the greater precision of natural language diagnoses makes them the most suitable vehicle for follow-up, retrieval, and systems development functions in pathology.

Artificial Intelligence↗
PubMed1988

Soft contact lens wear at altitude: effects of hypoxia.

In the U.S. Air Force, aircraft can be divided into two categories--those with cabin pressures equivalent to high altitudes and aircraft with cabin pressures equivalent to lower altitudes, with longer duration exposures. The purpose of this study was to determine the effects of soft contact lens wear under atmospheric pressures simulating these two types of aircraft environments. Ten subjects were tested to 7620 m (25,000 ft) in hypobaric chamber flights of 75 min and eight subjects were tested in hypobaric chamber flights at 3048 m (10,000 ft) for 4 h. Four subjects were also tested in dry air to further simulate cabin conditions. Vision and physiologic response were monitored by measurements of visual acuity, contrast sensitivity, and slit-lamp biomicroscopy examinations. The results of this study indicate that the physiologic responses of the cornea to soft contact lens wear at altitude are subject to higher levels of manifested stresses, but these occurred without measurable degradation in vision and did not preclude normal wear of soft contact lenses.

Aircraft↗
PubMed1988

Esophageal perforation due to pneumatic dilation for achalasia.

The initial treatment for achalasia in most centers is pneumatic dilation (PD). The most significant complication of PD is esophageal perforation (EP). During the past ten years, six patients were noted to have EP after PD at St. Luke's-Roosevelt Hospital Center. The cornerstone of treatment is early diagnosis. Operative repair, including suture of the perforation and modified Heller esophagomyotomy without anti-reflux procedure, is preferred. Details of this operation are presented. We have successfully managed five patients with EP after PD. A sixth patient died of unrecognized EP.

Adult↗
PubMed1987

Glutamine synthetase gene transcription in cultured 3T3-L1 adipocytes: regulation by dexamethasone, insulin and dibutyryl cyclic AMP.

We have investigated the regulation of glutamine synthetase (GS) mRNA synthesis in cultured 3T3-L1 adipocytes. Specific mRNA synthesis (transcription) was analyzed by measuring elongation of transcripts in isolated nuclei. Transcription rate was assayed by hybridization of newly synthesized [32P]RNA to a GS cDNA. GS transcription rate increased more than 100-fold during adipocyte differentiation and was inhibited more than 90% by alpha-amanitin. In 3T3-L1 adipocytes dexamethasone stimulated GS gene transcription while insulin and dibutyryl cAMP decreased GS gene transcription.

Adipose Tissue↗
PubMed1987

Acquisition of antigens characteristic of adult pericentral hepatocytes by differentiating fetal hepatoblasts in vitro.

Antigens specific to pericentral hepatocytes have been studied in adult mouse liver, during fetal development, and in cultured fetal hepatoblasts. Antibody reactive with glutamine synthetase stained all fetal liver cells but almost all cells lost this antigen after birth; only a single layer of pericentral cells retained it in adulthood. In contrast, monoclonal antibodies to major urinary protein (MUP) did not detect the antigen until approximately 3 wk after birth, after which time the cells within 6-10 cell diameters of the central veins were positive. Cultured fetal liver cells from embryos at 13 +/- 1 d of gestation were capable of differentiating in vitro to mimic events that would occur had the cells remained in the animal. About 10-20% of the explanted cells grew into clusters of hepatocyte-like cells, all of which stained with albumin antibodies. MUP monoclonals were reactive with one-half of the differentiated fetal hepatocytes. Glutamine synthetase was present in all hepatocytes after several days in culture and gradually decreased and remained in only occasional cells, all of which also contained the MUP antigen. These findings suggest that a sequence of gene controls characterizes expression of specific genes in developing liver, and that differentiating fetal hepatoblasts are capable of undergoing similar patterns of gene activity in culture.

Aging↗
PubMed1987

Insulin and dexamethasone stimulate transcription of an amplified glutamine synthetase gene in Chinese hamster ovary cells.

We have investigated the regulation of glutamine synthetase (GS) mRNA synthesis in Chinese hamster ovary cell mutants which overproduce GS and contain an amplified GS gene. Specific mRNA synthesis was analyzed by measuring elongation of transcripts in isolated nuclei. Transcription was assayed by hybridization of newly synthesized [32P]RNA to a genomic GS clone. Nuclear transcript elongation was inhibited more than 90% by alpha-amanitin. The relative rates of GS mRNA synthesis in nuclei from cells incubated for 2 days with no additions, insulin, dexamethasone, or (Bu)2cAMP are 186, 419, 375, and 227 ppm, respectively. The insulin- and dexamethasone-mediated increases in GS transcription rate (2-fold) were associated with 3.7- and 5.8-fold increases in GS mRNA abundance. By contrast, alpha-tubulin gene transcription was not altered by insulin or dexamethasone; however, it was decreased by (Bu)2cAMP.

Animals↗