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Biomedical subjects

M A Price

Publications and source records attributed to M A Price.

At least 37 records · Page 2Linked to original sources
PubMed1994

Multiagent pharmacotherapy to enhance skin flap survival: lack of additive effect of nitroglycerin and allopurinol.

Pathological vasospasm and free radical production contribute to skin flap necrosis. This study was undertaken to determine if postoperative combination therapy with the vasodilator nitroglycerin and the anti-free radical agent allopurinol would result in an additive enhancement of skin flap survival in the rat model. Thirty-one Sprague-Dawley rats were randomized into four groups and two cranially based dorsal skin flaps were raised on each rat. Both surgeon and data collector were blinded to treatments and all agents were given postoperatively. Control rats demonstrated 51 +/- 7.4% skin flap survival. Mean flap survival was significantly increased in groups receiving single agent therapy with either transdermal nitroglycerin (63 +/- 12% survival, mean +/- 2 SEM, p < 0.05) or intravenous allopurinol (62 +/- 10% survival, p < 0.01). No additional survival was seen in rats receiving both agents, which displayed 61 +/- 13% survival (p < 0.05, compared with controls). This study provides the first well-controlled demonstration that postoperatively applied transdermal nitroglycerin significantly enhances skin flap survival and includes a discussion of reasons for lack of additive effect of these agents.

Administration, Cutaneous↗
PubMed1994

Juvenile basal cell carcinoma.

A 17-year-old youth had a solitary basal cell carcinoma of the nose. This malignancy is rare in children and usually occurs with another disease or syndrome. The de novo form in this patient is especially rare.

Adolescent↗
PubMed1994

Beau's lines and pyogenic granulomas following hand trauma.

We report two cases of trauma-induced Beau's lines accompanied by pyogenic granulomas of the proximal nail folds of the affected fingers. The preceding trauma was not directly to the nail matrix but was more proximal, on the palm in one case and the arm in the other. The simultaneous occurrence of Beau's lines and pyogenic granulomas following trauma has not been reported previously in the literature.

Adolescent↗
PubMed1993

How the structure of an adenine tract depends on sequence context: a new model for the structure of TnAn DNA sequences.

We present a new model to explain the bending and local structural properties of TnAn sequences in DNA. Current models suggest that an adenine tract has the same unusual structure when found in a TnAn sequence as it has when surrounded by mixed-sequence B-DNA. On the basis of hydroxyl radical cleavage patterns of several TnAn sequences, we instead propose that the T2A2 or T3A3 core of such sequences is B-DNA-like but that adenines and thymines outside of this core, if sufficient in number, can form the unusual structure adopted by adenine tracts surrounded by mixed sequence DNA. We pursued further the structure of T7A7N7, a molecule which exhibits reduced electrophoretic mobility on native polyacrylamide gels and is therefore presumed to be bent. We attempted to mimic the structure of T7A7N7 that was predicted by our model by designing two new sequences, one in which the T3A3 core of T7A7N7 is substituted by six nucleotides of mixed sequence (N6) and the other in which the T2A2 core is replaced by N4. Hydroxyl radical cleavage patterns of all three molecules are nearly indistinguishable. All three molecules run anomalously slowly on a native polyacrylamide gel, with the mobility of T4N6A4N7 > T7A7N7 approximately T5N4A5N7. Analysis of the hydroxyl radical cutting pattern of T7A7N7 by Fourier transformation reveals the occurrence of an unusual structure at intervals of approximately 10 bp, a periodicity which is not evident in the sequence of the DNA.

Adenine↗
PubMed1992

Evidence for voltage modulation of IL-2 production in mitogen-stimulated human peripheral blood lymphocytes.

The membrane potential of human PBMC was modulated in culture by isotonic high extracellular K+ (K+e), or the K+ channel blocker, charybdotoxin (ChTX), to determine the effect of depolarization on stimulated proliferation, IL-2 elaboration, and gene expression. In serum-free cultures, ChTX and high [K+]e induced a specific dose-dependent decrease in IL-2 production. ChTX inhibited proliferation of PBMC and purified T cells, decreased IL-2 elaboration 15 h after stimulation by 78.4 +/- 5.3% (n = 5), and decreased IL-2 mRNA steady-state levels by 80% between 8 and 10 h after stimulation. The IC50 for ChTX-inhibition of IL-2 elaboration and IL-2 mRNA were both 1 nM. Similarly, high [K+]e inhibited proliferation with an IC50 of 38.9 +/- 1.1 mM (n = 13), decreased IL-2 elaboration with an IC50 of 21.3 +/- 1.2 mM (n = 6), and decreased IL-2 mRNA steady-state levels with an IC50 of 18 mM. The sensitivities of both IL-2 production and proliferation to depolarization were substantially reduced by calcium, serum, and exogenous rIL-2. From these findings we conclude that membrane potential may contribute to the control of immune responsiveness in vivo.

Blotting, Northern↗
PubMed1992

Analysis of puberty-accelerating pheromones.

Two experiments were performed to test putative puberty-accelerating pheromones. In the first experiment, 37 weanling female house mice of the ICR strain were exposed to 1 of the following 3 treatments: an airborne mixture of 0.05 M isoamylamine and 0.05 M isobutylamine, fresh male mouse urine, or distilled water, as the control. Neither the amine mixture nor the male urine accelerated first estrus in the mice following airborne exposure to these compounds. In the second experiment, 37 weanling female mice of the same strain were exposed to the same chemicals as in the first experiment by direct contact to the oro-nasal groove. The mixture of isoamylamine and isobutylamine did not accelerate puberty, but direct contact with the male urine accelerated puberty as evidenced by uterine weights.

Administration, Intranasal↗
PubMed1992

The effect of breed-type and castration on bone growth and distribution in cattle.

Data from carcasses of 210 cattle (119 bulls and 91 steers) from 4 breed types, serially slaughtered from approximately 200-800 kg kg liveweight were used to test the hypothesis of similar gender dimorphism among breeds in relation to carcass bone growth and distribution. Relative to total bone weight, breed types tended to have similar growth rates for all bones other than the cervical vertebrae, ribs, tibia and fibula, and tarsus. Adjusted to the same total bone weight there were significant differences among breed types in bone weight distribution, but the differences were very small and probably of little economic importance. Castration stimulated growth of the lumbar vertebrae, hindlimb bones, patella and hindquarter bones but inhibited growth of the ribs, scapula, carpus, forelimb bone, and forequarter bone. At the same total bone weight, steers as compared to bulls showed a shift in bone weight distribution towards the hindquarter, pistol and long bones. There were small but significant breed x gender interactions in the distribution of some bones.

Animals↗
PubMed1990

Biochemical and behavioral evidence for muscarinic autoreceptors in the CNS.

Muscarinic autoreceptors of the M2 subclass were examined in rat forebrain using a number of different methodologies, including receptor autoradiography and image analysis, regulation of acetylcholine release, phosphoinositide turnover, low-Km GTP hydrolysis, and behavioral analysis. The relatively minor population of M2 receptors in coronal sections was visualized by autoradiography and image analysis using [3H]quinuclidinyl benzilate in the presence of a concentration of pirenzepine that blocked most of M1 (and M4) receptors. The highest densities of M2 receptors in forebrain regions were found in the outer layers of the cortex, CA1 region of the hippocampus and striatum. The M2-, but not M1-selective antagonists were able to block the oxotremorine-induced attenuation of acetylcholine release in forebrain synaptosomes. Low concentrations of the M2-selective antagonist gallamine increased phosphoinositide turnover, which is thought to be an M1 postsynaptic response in the forebrain, in brain slices by a Ca2(+)-dependent mechanism. The M2-selective agonist oxotremorine produced a substantial stimulation of low-Km GTPase in cortical membranes, suggesting that M2 forebrain receptors are efficiently coupled to G-proteins in the cortex. Behavioral signs of cholinergic stimulation were observed after intracerebroventricular injections of M2-, but not M1-selective antagonists. It is suggested that a minor population of forebrain M2 receptors regulates acetylcholine release by a mechanism that includes coupling through G-proteins presynaptically at synapses for which the postsynaptic response involves phosphoinositide turnover. Selective blockade of these receptors produces both biochemical and behavioral signs of acetylcholine release.

Acetylcholine↗
PubMed1990

The injured canine cervical spine after six months of healing. An in vitro three-dimensional study.

The cervical spine is a common site of spinal injuries. The stability of an injured cervical spine is not only dependent on injury severity, but also on the degree of healing time. Using a canine model, three injuries of varying degrees of severity were surgically produced at the C4-C5 level and allowed to heal for 6 months. No internal or external support was provided. The harvested cervical spines (C2-C7) were subjected to three-dimensional biomechanical testing by applying individually six pure moments. The resulting three-dimensional displacements were recorded using stereophotogrammetry, and the intervertebral motions were calculated. The results are compared with the in vivo behavior of the same specimens and with an in vitro control group. At 1 N-m, the average flexion-extension range of motion (ROM) for the intact C4-C5 level was 24.5 degrees (standard deviation [SD], 6.6 degrees). A facetectomy at this level significantly increased the in vitro ROM to 51.1 degrees (SD, 4.4 degrees). The in vitro ROM decreased to 19.8 degrees (SD, 7.3 degrees) in the facetectomized group of this study, which were allowed to heal for 6 months before death. Similar results were obtained in axial rotation and lateral bending. The findings show that after 6 months of healing, the injured canine spine, although acutely hypermobile, exhibited biomechanical characteristics that were not different from those of the normal intact specimens.

Animals↗
PubMed1990

Plasma growth hormone and insulin concentrations in double-muscled and normal bull calves.

Blood samples were taken from 19 double-muscled (DM) and 20 normal (N) bull calves at the ages of 1.5, 2, 2.5, 3, 3.5, 4, 5.5, 6.5 and 9 mo to compare the plasma concentrations of growth hormone and insulin in DM with those in N bull calves and to relate these to differences in growth rate between the two breed groups. Double-muscled bull calves were lighter (P less than .0001) than N calves at all ages and had lower (P less than .001) preweaning and postweaning rates of gain. Double-muscled bull calves had lower (P less than .01) mean growth hormone concentration than N calves. Mean growth hormone concentration was correlated positively with body weight and preweaning rate of gain. The effect of age on growth hormone concentration was linear (P less than .05); however, mean growth hormone concentration fluctuated between ages 1.5 to 4.5 mo but stabilized after 5.5 mo of age in both breed groups. Mean insulin concentration was lower (P less than .01) in DM than in N bull calves. The effect of age on insulin concentration was both linear and quadratic (P less than .0001). Mean insulin concentration generally was constant in both breed groups, at around .75 ng/ml, from 1.5 to 6.5 mo of age but rose sharply to around 1.67 ng/ml after weaning when the bulls were put on a high-energy diet.

Animals↗
PubMed1989

Heterosis, maternal and direct effects in double-muscled and normal cattle: I. Reproduction and growth traits.

Data from a two-breed group diallel experiment involving double-muscled (DM) and normal (N) cattle were analyzed to evaluate the importance of heterosis, maternal and direct effects for reproduction and growth traits. The DM cattle were from a composite of primarily Angus, Charolais, Galloway and Hereford breeds, and N cattle were crossbred cattle with at least 50% Hereford breeding. The data comprised a total of 491 matings and 389 calvings in four breeding seasons. Records on calving performance, calving date, calf crop born and weaned, sex ratio of progeny and weight of calves were analyzed using least squares procedures. Significant heterosis of 5 to 12% was observed for all the calf crop and growth traits, except for birth weight. Heterosis resulted in 24% reduction in the incidence of dystocia and perinatal calf mortality (P less than .05). The significant heterosis was due mainly to poor production in DM X DM crosses. The DM cows were superior (P less than .05) to N cows in reciprocal crossing (maternal effect) for all the calf crop traits, but had higher incidence of calving difficulty and a higher proportion of male progeny. Significant direct effect was observed for all the traits except calving date and sex ratio among progeny. The N sires were superior for all the calf crop traits and caused less incidence of dystocia and perinatal mortality compared with the DM sires. Significant differences were obtained between the straightbreds for all the traits except calving date. The N straightbreds were superior to the DM straightbreds for all the significant traits.

Animal Feed↗
PubMed1989

Heterosis, maternal and direct effects in double-muscled and normal cattle: II. Carcass traits of young bulls.

Data on 135 young bulls from a two-breed group diallel experiment involving double-muscled (DM) and normal (N) cattle were analyzed to obtain estimates of heterosis, maternal and direct effects for carcass traits. When carcass traits were adjusted to a constant age at slaughter (398.5 d), significant positive heterosis was observed for slaughter and carcass weights, carcass length and s.c. fat thickness. Maternal effect was relatively unimportant for the traits studied. The progeny of N sires and DM straightbreds were heavier at slaughter and had higher carcass weight, s.c. fat thickness and carcass length (P less than .01), whereas DM-sired progeny and DM straightbreds had higher dressing percentage (P less than .05) and cutability (P less than .01). Heterosis was significant for all the 10-11-12th rib joint dissection traits except for percentage of muscle. Although there was negative heterosis for percentage of bone, there was positive heterosis for rib joint weight, fat weight and percentage, muscle weight and muscle:fat and muscle:bone ratios. For direct effect and straightbred differences, N-sired progeny and N straightbreds, respectively, had significantly larger values for rib joint weight, fat weight and percentage and bone weight. The DM-sired progeny and DM straightbreds had larger values for percentage of muscle, muscle:fat and muscle:bone ratios. When the carcass and dissection traits were adjusted to a constant carcass (303.7 kg) and rib joint (4,812 g) weight, respectively, the results were similar to those observed on age constant basis except for rib eye area, for which DM-sired progeny and DM straightbreds had larger values.

Adipose Tissue↗
PubMed1987

Inhibition of cleavage of a plant viral polyprotein by an inhibitor activity present in wheat germ and cowpea embryos.

In rabbit reticulocyte lysate, the bottom component RNA of cowpea mosaic virus directs the synthesis of a 200,000-molecular-weight precursor protein (200K protein) that is cleaved during synthesis by a reticulocyte enzyme to form a 32K protein and a 170K protein. Cleavage of the 200K protein was found to be effectively inhibited by inhibitor activity in wheat germ and cowpea embryo extracts. The inhibitor was nondialyzable, precipitatable by ammonium sulfate, and partially stable at high temperatures. The activity appeared to be specific in that it caused no inhibition of the secondary cleavage reactions (cleavage of the 170K protein) at concentrations that were sufficient to cause complete inhibition of the primary cleavage reaction (cleavage of the 200K protein).

Journal Article↗
PubMed1986

Structure of a stable form of sulfheme.

A stable green heme was extracted from ferric cyanosulfmyoglobin after it had undergone an internal conversion reaction. After iron removal and conversion to the methyl ester, the resulting green porphyrin was purified by high-pressure liquid chromatography. Visible, 1H NMR, and mass spectrometric studies provided evidence to identify the substituents of the porphyrin. Nuclear Overhauser enhancements enabled an assignment of the single modified pyrrole. Substituent positions 1, 2, 5, 6, 7, and 8 have the original protoporphyrin IX substituents. At ring B, the 4-vinyl group has cyclized with a single sulfur atom to form a fifth ring with a 2,5-dihydrothiophene type of structure.

Animals↗
PubMed1985

Paralysis in herpes zoster.

Herpes zoster is a relatively common disease which affects predominantly the middle-aged and elderly. The segmentally distributed cutaneous eruption, sensory changes, and pain make up the well known zoster syndrome. Motor loss is another aspect of this syndrome which is less well known but occurs in a significant number of cases, and is probably far more frequent than is recognised because the weakness is readily obscured by pain. Four cases of herpes zoster with motor involvement are described. Two cases had zoster paresis affecting the arm and hand, and one of these had, in limb, and one case had urinary retention owing to an atonic bladder. These cases serve to illustrate many of the clinical features of the zoster syndrome with motor involvement. The significant functional implications of unrecognised motor deficit, particularly in the elderly, are a prominent feature and highlight the importance of early accurate diagnosis and management. The pathogenesis and clinical features of this syndrome are discussed in the literature review.

Aged↗
PubMed1985

Failure of antiplatelet therapy with ibuprofen (Motrin) to prevent neointimal fibrous hyperplasia.

To evaluate the effect of ibuprofen (Motrin) on the development of neointimal fibrous hyperplasia (NFH), 4 cm segments of expanded polytetrafluoroethylene (ePTFE) grafts with an internal diameter of 4 mm were implanted in the femoral arteries of 28 dogs. Three dogs served as controls and these grafts were removed at 7 to 14 days. The remaining 25 dogs were medicated with either intravenous (IV) or oral (PO) ibuprofen. The medicated dogs were grouped according to whether the ibuprofen was administered prior to or after graft implantation. The orally medicated dogs were also grouped according to whether the grafts were removed from 30 to 60 days after graft implantation. The grafts were analyzed for the amount of anastomotic initimal hyperplasia, pannus extension, thrombus deposition, and patency. Analysis of the data demonstrated no statistically significant differences among any of the treatment groups or the control group for the variables analyzed. We conclude that ibuprofen neither prevents nor retards the development of NFH. There was a trend toward less thrombus deposition in the animals that received oral ibuprofen preoperatively. There was also a trend toward higher patency in the animals that received ibuprofen prior to graft implantation, which most likely resulted from decreased thrombus and fibrin deposition.

Animals↗
PubMed1984

Capillary blood flow: videodensitometry in the atherosclerotic patient.

Recently the noninvasive technique of videomicroscopy has demonstrated qualitative morphologic changes in the nutritional skin capillaries in atherosclerotic (ATS) patients. The purpose of this study is to quantitatively examine the ATS microcirculation and effects induced by reconstructive surgery. Capillary blood flow velocity (CBV) of single vessels within the nail fold of the large toe was measured by dual-sensor videodensitometry in 14 ATS patients (age 45 to 80 years) and 11 age-matched controls. In addition to CBV, capillary diameter (CD) and the number of flow-active capillaries (FC) were also measured at constant temperature. Of the 14 patients, eight had measurements repeated 1 week after reconstructive surgery. The measurements were obtained at rest and then periodically after a 45-second period of pedal inflow occlusion. Respective group averages at rest for CBV, CD, and FC for the 14 ATS patients were as follows: 0.16 mm/sec, 10.5 micron, and 6.8 capillaries per field. Corresponding values for the control subjects were 0.10 mm/sec, 8.7 micron, and 5.3 capillaries per field. Combining CBV, CD, and FC into a measurement of volume capillary flow yielded a value of 281 pl/sec/mm2 for the patients and only 85 pl/sec/mm2 for the controls (p less than 0.02). Peak postocclusion CBV significantly increased, whereas FC significantly decreased relative to rest in the control group; however, the only patient group that responded to occlusion-induced ischemia was the postoperative group. In these patients there was a decrease in CBV and an increase in FC relative to rest. These responses are exactly opposite to those in the age-matched controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗