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Biomedical subjects

J B Miller

Publications and source records attributed to J B Miller.

At least 73 records · Page 4Linked to original sources
PubMed1994

Plasma glucose levels after prolonged strenuous exercise correlate inversely with glycemic response to food consumed before exercise.

It was hypothesized that slowly digested carbohydrates, that is, low glycemic index (GI) foods, eaten before prolonged strenuous exercise would increase the blood glucose concentration toward the end of exercise. Six trained cyclists pedaled on a cycle ergometer at 65-70% VO2max 60 min after ingestion of each of four test meals: a low-GI and a high-GI powdered food and a low-GI and a high-GI breakfast cereal, all providing 1 g of available carbohydrate per kilogram of body mass. Plasma glucose levels after more that 90 min of exercise were found to correlate inversely with the observed GI of the foods (p < .01). Free fatty acid levels during the last hour of exercise also correlated inversely with the GI (p < .05). The findings suggest that the slow digestion of carbohydrate in the prevent food favors higher concentrations of fuels in the blood toward the end of exercise.

Adult↗
PubMed1994

Medical resource allocation: rationing and ethical considerations--Part I.

The United States' system of high-quality but expensive and poorly distributed medical care is in trouble. Dramatic advances in medical knowledge and procedures, combined with soaring demands created by growing public awareness, the cost of private hospital and medical insurance, and Medicare and Medicaid, are burdening the medical care delivery systems. The costs of medical care have reached levels that can no longer be sustained. Government officials, insurance planners, labor leaders responsible for union health care benefits, and ordinary citizens are questioning whether it is acceptable to limit health care based on economic considerations. If health care is deemed a social good, the method of allocation must be addressed. Unless society decides that other priorities of the infrastructure are to be subjugated to health service delivery, difficult decisions will be forced upon us, consciously or by default. The discussion in this two-part article explores the ethical considerations of the more formalized approaches to resource allocation that presently exist in our society.

Aged↗
PubMed1994

Medical resource allocation: rationing and ethical considerations, Part II.

The proliferation of medical technology during the past decade has doubtless surpassed that of any other recent period. We have witnessed and are continuing to witness rapid advances in human genetic engineering, reproductive technology, and biomedical intervention in the life process. Our population has benefitted from this technology as a result of its ability to extend the life of individuals, particularly the elderly sector of our society. This technological proliferation has caused philosophers, physicians, engineers, and policy strategists to focus upon questions of ethics and mortality relating to their application. In approaching the ethics of rationing, consideration must be given to both the deontological concepts of the individual and the utilitarian principles of societal preservation. This article continues a discussion of the issues of resource allocation that was begun in the February 1994 issue of Physician Executive.

Advance Directives↗
PubMed1994

Particle size, satiety and the glycaemic response.

OBJECTIVE: This study investigated the hypothesis that the smaller the particle size of the food, the higher the glycaemic-insulin response and the lower the satiety rating. DESIGN AND SUBJECTS: Ten healthy subjects consumed equal carbohydrate portions of four test meals of equivalent nutritional composition based on four different grades of wheat: whole grains, cracked grains, coarse and fine wholemeal flour. RESULTS: The mean overall plasma glucose response (area under the curve: AUC) was highest for the fine flour meal (4205 +/- 451 mmol/l.120 min), followed by the coarse flour and cracked grain meals and lowest for the whole grain meal (1524 +/- 190 mmol/l.120 min). Insulin responses showed the same ranking but satiety responses were the reverse, the fine flour meal giving the lowest satiety response [AUC: 231.4 +/- 31.6 rating scale (RS) units.120 min] and the whole grain meal the highest response (AUC: 318.4 +/- 29.3 RS units.120 min). Total insulin responses (AUC) were significantly associated with subjective satiety when analyses on an individual basis (analysis of covariance coefficient = -0.024, P < 0.04) such that for every 1000 unit increase in AUC insulin, satiety decreased by 24 units (13% on average). CONCLUSION: The results suggest that the processing of cereals is not only a major determinant of the glycaemic and insulin response but also affects the levels of postprandial satiety.

Adult↗
PubMed1993

Comparison of computed tomography with radiography as a noninvasive diagnostic technique for chronic nasal disease in dogs.

Computed tomography was evaluated as a noninvasive technique for the diagnosis of chronic nasal disease in dogs. Computed tomographic images, radiographs, and histopathologic findings were compared in 11 dogs with chronic nasal disease. Definitive diagnosis was made following traumatic nasal flush, exploratory surgery, or necropsy. The study included 8 dogs with intranasal tumors, 2 dogs with bacterial rhinitis (Pasteurella sp), and 1 dog with mycotic rhinitis (Aspergillus sp). Computed tomography was superior to radiography in defining the extent of the disease process and in differentiating infectious rhinitis from nasal neoplasms. It defined lesions in the palate, nasopharyngeal meatus, maxillary sinus, caudal ethmoturbinates, and periorbital tissues that were difficult to demonstrate by use of conventional radiography. Tumors appeared as space-occupying lesions that obliterated the turbinates, caused deviation of the nasal septum, and eroded bone. Rhinitis appeared as a cavitating lesion that spared the paranasal sinuses, thickened and distorted the turbinates, and widened the meatus. Although morphologically distinct on computed tomographic images, infectious rhinitis and nasal neoplasms could not be differentiated by attenuation measurements or degree of contrast enhancement. Computed tomography appeared to be a reliable, noninvasive technique for the diagnosis of chronic nasal disease in dogs, and a promising alternative to diagnostic techniques currently in use.

Animals↗
PubMed1993

Cellular and molecular diversity in skeletal muscle development: news from in vitro and in vivo.

Skeletal muscle formation is studied in vitro with myogenic cell lines and primary muscle cell cultures, and in vivo with embryos of several species. We review several of the notable advances obtained from studies of cultured cells, including the recognition of myoblast diversity, isolation of the MyoD family of muscle regulatory factors, and identification of promoter elements required for muscle-specific gene expression. These studies have led to the ideas that myoblast diversity underlies the formation of the multiple types of fast and slow muscle fibers, and that myogenesis is controlled by a combination of ubiquitous and muscle-specific transcriptional regulators that may be different for each gene. We further review some unexpected results that have been obtained when ideas from work in culture have been tested in developing animals. The studies in vivo point to additional molecular and cellular mechanisms that regulate muscle formation in the animal.

Animals↗
PubMed1993

Parental disclosure from the perspective of late adolescents.

Although parental relations are considered influential in adolescents' transition to adulthood, we know little about lessons that parents provide through self-disclosure. This study explored the content and extent of parents' disclosure, from the perspective of their children in late adolescence. College students were asked to indicate how much each parent had shared about various matters in their lives, to characterize the quality of each parent's disclosure to them and their disclosure to each parent, and to recall each parent's most meaningful, awkward and first disclosures. Based on previous research regarding adolescents' disclosure to parents, gender differences in disclosure, and reciprocity of disclosure, it was predicted that greater disclosure would be exchanged with mothers than with fathers. Results confirmed initial predictions, indicated some of the functions that parental disclosure may serve, and suggested a model by which intra-family disclosure might evolve.

Adolescent↗
PubMed1993

Chorionic gonadotropin, estradiol, and progesterone levels in baboons (Papio anubis) during early pregnancy and spontaneous abortion.

The purpose of this study was to sequentially characterize peripheral chorionic gonadotropin (CG), estradiol (E2), and progesterone (P) profiles during early pregnancy in the baboon (Papio anubis). Ten pregnant baboons were bled sequentially at eighteen time points between Days 8 and 128 of gestation. In addition, blood was obtained at corresponding time points from 5 spontaneously aborting baboons. CG levels were assessed in a mouse Leydig cell bioassay using rhesus pituitary LH as the standard E2 and P levels were measured by RIA. Pregnancy-associated CG activity was detectable by Day 15 (901.4 +/- 275.6 ng/ml), peaked at Day 27 (53,494.1 +/- 14,995.6 ng/ml), and then returned to baseline values by Day 51 (45.4 +/- 8.9 ng/ml). Mean E2 concentrations rose from 28.9 +/- 4.3 pg/ml on Day 8 to 280.6 +/- 145.5 pg/ml on Day 58 and then increased 9-fold to a level of 2436.4 +/- 928.0 pg/ml on Day 72. Mean E2 concentrations ranged between 2065.9 and 3830.9 pg/ml from Day 72 through Day 128. Mean P concentrations ranged from 7.5 to 10.2 ng/ml between Days 8 and 21, rising dramatically to 38.6 +/- 4.6 ng/ml on Day 37 prior to declining to levels that ranged from 11.1 to 17.1 ng/ml between Days 51 and 128. CG levels were low in 3 of 5 animals prior to spontaneous abortion E2 and P concentrations preceding spontaneous abortion were similar to values in uncomplicated pregnancy; however, at the time abortion was detected P concentrations in all 5 animals were 1.3 ng/ml or less.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Veterinary↗
PubMed1993

A unique pattern of expression of the four muscle regulatory factor proteins distinguishes somitic from embryonic, fetal and newborn mouse myogenic cells.

A unique pattern of expression of the four muscle regulatory factor (MRF) proteins was found to distinguish early somitic from embryonic, fetal and newborn limb myogenic cells in vitro. Expression of the myosin heavy chain (MHC), MyoD, myogenin, Myf-5, and MRF4 proteins was examined by immunocytochemistry in cultures of four distinct types of mouse myogenic cells: somitic (E8.5), embryonic (E11.5), fetal (E16.5) and newborn limb. In embryonic, fetal and newborn cultures, the MRF proteins were expressed in generally similar patterns: MyoD was the first MRF expressed; MyoD and myogenin were expressed by more cells than Myf-5 or MRF4; and each of the four MRFs was found both in cells that expressed MHC and in cells that did not express MHC. In cultures of somitic cells, in contrast, Myf-5 was expressed first and by more cells than MyoD or myogenin; MRF4 was not detected; and the MRFs were never found to be coexpressed with MHC in the same cell. Thus, some somitic cells had the unexpected ability to maintain MHC expression in the absence of detectable MRF protein expression. The different myogenic programs of embryonic, fetal and newborn myogenic cells are not, therefore, a simple result of qualitatively different MRF expression patterns, whereas myogenesis by somitic cells does include a unique pattern of MRF expression.

Animals↗
PubMed1992

Estrogen modulates Ca(2+)-independent lipid-stimulated kinase in the rabbit corpus luteum of pseudopregnancy. Identification of luteal estrogen-modulated lipid-stimulated kinase as protein kinase C delta.

Rabbit corpora lutea were tested for the presence of phosphorylative responses sensitive to estrogen. Luteal Ca(2+)-independent lipid-stimulated kinase activity was detected by phosphorylation of the endogenous substrate, p76. Estrogen treatment, by way of estradiol-17 beta implant, increased levels of the lipid-stimulated phosphoprotein 2-3-fold throughout pseudopregnancy. Midpseudopregnant rabbit luteal extracts were further evaluated to determine the identity of the lipid-stimulated kinase. Results of low pH-activated phosphorylation were consistent with the identification of p76 as an autophosphorylated member of the protein kinase C (PKC) family. Partial purification of the luteal lipid-stimulated kinase was performed using sequential DEAE-cellulose/hydroxylapatite chromatographies and using gel filtration. Western immunoblot with type-specific anti-PKC delta antiserum showed coelution of kinase p76 activity with immunoreactive PKC delta. Immunoblot analysis confirmed that luteal levels of PKC delta were increased by estrogen treatment.

Animals↗
PubMed1992

Skin necrosis and protein C deficiency associated with vitamin K depletion in a patient with renal failure.

Skin necrosis similar to that induced by warfarin was seen in a patient who had never received the drug but who was vitamin K-deficient due to malnutrition and prolonged treatment with broad-spectrum antibiotics. He also had end-stage renal failure and was receiving prophylactic subcutaneous heparin therapy because of immobilization. His plasma protein C antigen level and, disproportionately, his plasma protein C functional activity were decreased. Both protein C values improved after vitamin K therapy, discontinuation of heparin, and initiation of hemodialysis. We surmise that skin necrosis occurred as a result of protein C deficiency caused by vitamin K depletion. Production of abnormal (descarboxy) protein C/protein S due to vitamin K deficiency and increased protein C inhibitory activity associated with renal failure and/or heparin administration may have contributed to the clinical picture. This rare but serious complication of a relatively common disorder, viz., vitamin K deficiency, reinforces the importance of vitamin K supplementation in malnourished patients who receive long-term antibiotic maintenance therapy.

Adult↗
PubMed1992

Developmentally regulated expression of three slow isoforms of myosin heavy chain: diversity among the first fibers to form in avian muscle.

At least three slow myosin heavy chain (MHC) isoforms were expressed in skeletal muscles of the developing chicken hindlimb, and differential expression of these slow MHC isoforms produced distinct fiber types from the outset of skeletal muscle myogenesis. Immunohistochemistry with isoform-specific monoclonal antibodies demonstrated differences in MHC content among the fibers of the dorsal and ventral premuscle masses and distinctions among fibers before splitting of the premuscle masses into individual muscles (Hamburger and Hamilton Stage 25). Immunoblot analyses by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of myosin extracted from the hindlimb demonstrated the presence throughout development of different mobility classes of MHCs with epitopes associated with slow MHC isoforms. Immunopeptide mapping showed that one of the MHCs expressed in the embryonic limb was the same slow MHC isoform, slow MHC1 (SMHC1), that is expressed in adult slow muscles. SMHC1 was expressed in the dorsal and ventral premuscle masses, embryonic, fetal, and some neonatal and adult hindlimb muscles. In the embryo and fetus SMHC1 was expressed in future fast, as well as future slow muscles, whereas in the adult only the slow muscles retained expression of SMHC1. Those embryonic muscles destined in the adult to contain slow fibers or mixed fast/slow fibers not only expressed SMHC1, but also an additional slow MHC not previously described, designated as slow MHC3 (SMHC3). Slow MHC3 was shown by immunopeptide mapping to contain a slow MHC epitope (reactive with mAb S58) and to be structurally similar to a MHC expressed in the atria of the adult chicken heart. SMHC3 was designated as a slow MHC isoform because (i) it was expressed only in those muscles destined to be of the slow type in the adult, (ii) it was expressed only in primary fibers of muscles that subsequently are of the slow type, and (iii) it had an epitope demonstrated to be present on other slow, but not fast, isoforms of avian MHC. This study demonstrates that a difference in phenotype between fibers is established very early in the chicken embryo and is based on the fiber type-specific expression of three slow MHC isoforms.

Animals↗
PubMed1992

Distinct myogenic programs of embryonic and fetal mouse muscle cells: expression of the perinatal myosin heavy chain isoform in vitro.

Early embryonic and late fetal mouse myogenic cells showed distinct patterns of perinatal myosin heavy chain (MHC) isoform expression upon differentiation in vitro. In cultures of somite or limb muscle cells isolated from Day 9 to Day 12 embryos, differentiated cells that expressed perinatal MHC were rare and perinatal MHC was not detectable by immunoblotting. In cultures of limb muscle cells isolated from Day 13 to Day 18 fetuses, in contrast, the perinatal MHC isoform was easily detected and was expressed in a substantial percentage of myocytes and myotubes. Analyses of clonally derived muscle colonies and cytosine arabinoside-treated fetal muscle cell cultures suggested that different fetal muscle cell nuclei initiated perinatal MHC expression at different times. In both embryonic and fetal cell cultures, the embryonic MHC isoform was expressed by all differentiated cells examined. A small number of myotubes in fetal muscle cell cultures showed a mosaic distribution of MHC isoform accumulation in which the perinatal MHC isoform accumulated in a restricted region of the myotube near particular nuclei, whereas the embryonic MHC isoform accumulated throughout the myotube. Thus, the myogenic program of fetal, but not embryonic, mouse myogenic cells includes expression of the perinatal MHC isoform upon differentiation in culture.

Animals↗
PubMed1992

Multiple pulse NMR imaging of polymers and chemistry.

Multiple pulse line narrowing techniques can be used to improve resolution and sensitivity in solid state NMR imaging. For example, pulse sequences which remove homonuclear dipolar broadening have been used to image proton-containing materials. Further enhancements in resolution and sensitivity are obtained by removing inhomogeneous interactions such as chemical shift, susceptibility, and heteronuclear dipolar broadening. Pulse sequences have been designed which provide efficient line narrowing over large spectral widths by taking into account the experimenter's control over the amplitude and time dependence of the gradient-induced resonance offset. These methods have been applied to centimeter sized samples to obtain images of polymers, composite materials, and gas-solid chemical reactions. T1 and T2 contrast allows differentiation between materials.

Magnetic Resonance Spectroscopy↗