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Showing papers by "University of Nevada, Reno published in 1991"


Journal ArticleDOI
TL;DR: In this article, the authors examined the multivariate relationship between a set of explanatory variables and audit delay for a large sample of New Zealand public companies and found that both company size and sign of income significantly affect audit delay across the two years examined.
Abstract: An important qualitative attribute of financial statements is timeliness. The recognition that the length of the audit may be the single most important determinant affecting the timing of earnings' announcements has motivated recent research on audit delay. The present study extends prior research by examining the multivariate relationship between a set of explanatory variables and audit delay for a large sample of New Zealand public companies. Further, the study includes two explanatory variables, company control (i.e. owner control versus manager control) and debt proportion, which have not previously been considered. The results indicate that both company size and sign of income significantly affect audit delay across the two years examined. Five other explanatory variables significantly affected audit delay for one of the two years examined. The adjusted R2s of the regression models, however, were relatively low. Additional analysis was also performed on each company control subsample. These ...

270 citations


Journal ArticleDOI
TL;DR: The incidence of pathological gambling was high among males, Hispanics, Asians, and Italian-Americans (compared with among other whites), students with non-traffic arrests, those with parents who have gambling problems, and those who abuse alcohol and other drugs.

263 citations


Journal ArticleDOI
TL;DR: In this paper, biochemical and immunological techniques were used to demonstrate that these proteins coexist in the same avian Purkinje neurons, where they have different intracellular distributions.
Abstract: Two intracellular calcium-release channel proteins, the inositol trisphosphate (InsP3), and ryanodine receptors, have been identified in mammalian and avian cerebellar Purkinje neurons. In the present study, biochemical and immunological techniques were used to demonstrate that these proteins coexist in the same avian Purkinje neurons, where they have different intracellular distributions. Western analyses demonstrate that antibodies produced against the InsP3 and the ryanodine receptors do not cross-react. Based on their relative rates of sedimentation in continuous sucrose gradients and SDS-PAGE, the avian cerebellar InsP3 receptor has apparent native and subunit molecular weights of approximately 1,000 and 260 kD, while those of the ryanodine receptors are approximately 2,000 and 500 kD. Specific [3H]InsP3- and [3H]ryanodine-binding activities were localized in the sucrose gradient fractions enriched in the 260-kD and the approximately 500-kD polypeptides, respectively. Under equilibrium conditions, cerebellar microsomes bound [3H]InsP3 with a Kd of 16.8 nM and Bmax of 3.8 pmol/mg protein; whereas, [3H]ryanodine was bound with a Kd of 1.5 nM and a capacity of 0.08 pmol/mg protein. Immunolocalization techniques, applied at both the light and electron microscopic levels, revealed that the InsP3 and ryanodine receptors have overlapping, yet distinctive intracellular distributions in avian Purkinje neurons. Most notably the InsP3 receptor is localized in endomembranes of the dendritic tree, in both the shafts and spines. In contrast, the ryanodine receptor is observed in dendritic shafts, but not in the spines. Both receptors appear to be more abundant at main branch points of the dendritic arbor. In Purkinje neuron cell bodies, both the InsP3 and ryanodine receptors are present in smooth and rough ER, subsurface membrane cisternae and to a lesser extent in the nuclear envelope. In some cases the receptors coexist in the same membranes. Neither protein is observed at the plasma membrane, Golgi complex or mitochondrial membranes. Both the InsP3 and ryanodine receptors are associated with intracellular membrane systems in axonal processes, although they are less abundant there than in dendrites. These data demonstrate that InsP3 and ryanodine receptors exist as unique proteins in the same Purkinje neuron. These calcium-release channels appear to coexist in ER membranes in most regions of the Purkinje neurons, but importantly they are differentially distributed in dendritic processes, with the dendritic spines containing only InsP3 receptors.

261 citations


Journal ArticleDOI
TL;DR: Testing the hypothesis that pregnant females should move to areas that maximize nutrient intake once the demands of gestation are high, even at the risk of increased predation, suggests species of mammals with access to heterogeneous environments prior to parturition are ideal subjects to examine the extent to which habitat shifts result from balancing increased dietary requirements during late gestation and safety from potential predators.

239 citations


Journal ArticleDOI
TL;DR: In this paper, the authors survey applications of economic analysis to tourism using consumer and production theory, market structure, deductive modeling, cost-benefit analysis, econometric analysis, and multiplier analysis.

214 citations


Journal ArticleDOI
TL;DR: The purpose of this study was to examine the transfer of consequential (reinforcement and punishment) functions through equivalence relations, and whether equivalence training had established general or specific consequential functions primarily by adding novel stimuli in the transfer test.
Abstract: The purpose of this study was to examine the transfer of consequential (reinforcement and punishment) functions through equivalence relations. In Experiment 1, 9 subjects acquired three three-member equivalence classes through matching-to-sample training using arbitrary visual forms. Comparison stimuli were then given conditioned reinforcement or punishment functions by pairing them with verbal feedback during a sorting task. For 8 of the 9 subjects, trained consequential functions transferred through their respective equivalence classes without additional training. In Experiment 2, transfer of function was initially tested before equivalence testing per se. Three of 4 subjects showed the transfer without a formal equivalence test. In Experiment 3, 3 subjects were given training that gave rise to six new three-member conditional equivalence classes. For 2 of the subjects, the same stimulus could have either a reinforcement or punishment function on the basis of contextual cues that defined its class membership. Experiment 4 assessed whether equivalence training had established general or specific consequential functions primarily by adding novel stimuli in the transfer test. Subjects treated even novel feedback stimuli in the transfer test as consequences, but the direction of consequential effects depended upon the transfer of specific consequential functions through equivalence relations.

204 citations


Journal ArticleDOI
TL;DR: In this paper, the authors studied the distribution of surface ruptures caused by 11 historical earthquakes in the Basin and Range province of western North America and provided a basis for evaluating earthquake segmentation behavior of faults in extensional tectonic settings.

200 citations


Journal ArticleDOI
TL;DR: The method is specifically designed to reduce the amount of insoluble polysaccharides associated with cultured cell material and to maintain an efficient yield of intact RNA suitable for poly (A) enrichment and analysis of less abundant transcripts.
Abstract: Total cellular RNA has commonly been prepared from plant material utilizing methods involving CTAB (cetyltrimethylammonium bromide), SDS (sodium dodecyl sulfate), phenol/chloroform, or guanidine hydrochloride (Logemann et al, 1987). Although very effective in the preparation of intact RNA from leaf tissue, when applied to cultured plant cells these methods all result in a low yield and a substantial contamination by polysaccharides. The procedure outlined in this report is a substantial modification of a published method developed for minipreparation of plant leaf RNA (Verwoerd et al, 1989). Our method is specifically designed to reduce the amount of insoluble polysaccharides associated with cultured cell material and to maintain an efficient yield of intact RNA suitable for poly (A) enrichment and analysis of less abundant transcripts.

191 citations


Journal ArticleDOI
TL;DR: High-grade dysplasia is an important marker of malignancy in patients with a columnar-lined esophagus and esophagectomy is indicated in suitable candidates since carcinoma was found in 45% of the authors' patients.
Abstract: Abnormal columnar lining of the esophagus is a well-recognized premalignant condition. The management of patients with high-grade dysplasia without evidence of carcinoma remains controversial. Esophagectomy is proposed by some investigators, whereas others favor follow-up endoscopy and biopsy until microinvasive malignancy is documented. We reviewed our experience with nine patients referred with high-grade dysplasia on endoscopic biopsies without evidence of carcinoma. Eight patients had the columnar lining extending orad from the cardia, and one patient had heterotopic columnar epithelium in the cervical esophagus. All were white men ranging in age from 19 to 76 years (median: 47 years). Eight patients underwent esophagectomy with colon interposition. A sleeve resection of the cervical esophagus was done in one patient. Multifocal carcinoma was found in three patients, all of whom had severe dysplastic changes throughout the columnar lining. The patient with heterotopic columnar epithelium had microinvasive carcinoma. All four patients with carcinoma had negative nodes and are long-term survivors. No carcinoma was found in the resected specimens of the remaining five patients. High-grade dysplasia is an important marker of malignancy in patients with a columnar-lined esophagus. Esophagectomy is indicated in suitable candidates since carcinoma was found in 45% of our patients.

175 citations


Journal ArticleDOI
TL;DR: Early pelvic fracture fixation reduces hospital stay, long-term disability, and may result in fewer complications, decreased blood loss, and better survival.
Abstract: Thirty-seven consecutive patients with unstable pelvic fractures were divided into two groups: Group 1 (July 1981 to December 1984; n = 18), when early fixation was not routinely used, and Group 2 (January 1985 to March 1988; n = 19), when early fixation was performed unless contraindicated. Hospital stay decreased by 37.8% in Group 2 (p = 0.04). Of Group 1 patients, 60% were disabled for at least 6 months versus 15.7% in Group 2 (p = 0.001), and 45% were discharged to a rehabilitation facility versus 26.4% in Group 2. Group 1 had more complications, 1.3 per patient, versus 1.0. Patients in Group 2 (undergoing early fixation) required 27.2% fewer units of blood than those in Group 1 in whom fracture surgery was delayed. Survival was better in Group 2, 100% versus 83.3% (p = 0.06). Early pelvic fracture fixation reduces hospital stay, long-term disability, and may result in fewer complications, decreased blood loss, and better survival.

165 citations


Journal ArticleDOI
TL;DR: Cramer et al. as mentioned in this paper showed that salinity had significant effects on the uptake and concentrations of most elements in barley, including Na, Ca, Mg, K, S, P, Fe, Mn,Cu and Zn.
Abstract: Cramer, G. R., Epstein, E. and Lauchli, A. 1991. Effects of sodium, potassium apdcalcium on salt-stressed barley. !I. Elemental analysis. - Physiol. Plant. 81; 197-202.We grew bariey (Hordeum vulgare L. CM 72) for a 28-day period and sequentiallyharvested plants every 3 or 4 days. Plants were salt-stressed with either NaCI or KCl(125 mM) with or without supplemental Ca (10 or 0,4 mM final concentration,respectively). We determined tissue concentrations of Na, Ca, Mg, K, S, P, Fe, Mn,Cu and Zn for each harvest date by inductively coupled plasma spectrometry. Uptake(specific absorption rate) was calculated from the element content and growth rates.Salinity had significant effects on the uptake and concentrations of most elements.Mg and Mn concentrations declined with time. The concentrations of all otherelements determined increased over time. Element uptake on a root dry weight basisdeclined with time. Three variables were significantly affected by salinity and corre-lated with growth; 1) the Ca concentration, 2) the total sum of the cation concentra-tion (TC), and 3) the Mn concentration of the shoot. Salinity reduced Ca uptake andconcentrations. Supplemental Ca increased Ca concentrations and was positivelycorrelated with growth during salt stress. Salinity doubled TC, which was negativelycorrelated with relative growth rate (RGR), Relative growth rate declined at TCvalues above 150 mM. Salinity reduced the uptake and concentration of Mn. Manga-nese concentrations in the shoot were highly correlated with RGR. Relative growthrate declined at Mn concentrations below 50 nmol (g fresh weight) ',Key words - Barley, Ca, Hordeum vulgare, K, Mn, Na, Na-Ca interactions, salinity,uptake.G, R, Cramer (corresponding author), Dept of Ptant Science, Univ, of Nevada, Reno,NV 89557, USA; E. Epstein and A. Lauchli, Dept of Land, Air and Water Resources,Univ, of California, Davis, CA 95616, USA.

Journal ArticleDOI
01 Aug 1991-Spine
TL;DR: It is suggested that cigarette smoking may be a significant risk factor for postoperative wound infections after posterior spinal instrumentation and fusion and patients without normal host defenses, Classes B and C, are at high risk for developing postop-erative wound infection.
Abstract: A multicenter study was undertaken to analyze postoperative wound infections after posterior spinal instrumentation and fusion. The infection rate of these procedures has been documented in multiple reports. From these results, a classification scheme was developed that can guide therapy and determi

Journal ArticleDOI
01 Apr 1991-Nature
TL;DR: In this article, the authors used radiocarbon ages obtained using accelerator mass spectrometry for the organic fraction of recent Black Sea sediments to estimate the organic carbon accumulation rates.
Abstract: THE Black Sea, the world's largest anoxic marine basin, is frequently used as a modern analogue for the formation of organic-rich sediments and carbonaceous rocks1–3, on the widely held assumption that anoxic conditions promote the preferential preservation of organic matter in sediments. Data for testing this hypothesis have so far been equivocal4–7, but here we use radiocarbon ages obtained using accelerator mass spectrometry for the organic fraction of recent Black Sea sediments to estimate the organic carbon accumulation rates. These range from 0.69 to 2.09 g C m−2 yr−1 and are significantly lower than earlier estimates based on varve counting6. Depending on the value taken for the rate of primary production in the Black Sea4,8, between 0.7 and 2.1% of the organic carbon is preserved in the bottom sediments. When compared with carbon accumulation rates in equivalent oxygenated environments9, these results indicate that the modern Black Sea is not a site of anomalously high organic carbon accumulation. This suggests that anoxic conditions in the water column may not be a prerequisite for the preservation of organic matter in marine sediments, and that models of the origin of carbonaceous facies in the geological record may therefore need to be modified.

Journal ArticleDOI
TL;DR: On a ajoute de 0,29 a 2,38% de Sb 2 O 3 a ZnO de haute purete as discussed by the authors, on examine la croissance de grain lors du frittage dans l'air a 1106-1400 o C.
Abstract: On a ajoute de 0,29 a 2,38% de Sb 2 O 3 a ZnO de haute purete. On examine la croissance de grain lors du frittage dans l'air a 1106-1400 o C. On compare les resultats avec ceux de ceramiques de ZnO pur et additionne de Bi 2 O 3

Journal ArticleDOI
TL;DR: Examination of inter-and intra-individual variation showed that the relationship between growth and reproduction depends on the age of subjects, and there were long-term benefits: fecundity in the first 7–9 years was highest for early-maturing and lowest for late-matured females, suggesting that reproductive success is greater for early -maturing females despite reduced growth.
Abstract: The extent to which (a) larger females produce more or larger offspring, (b) reproduction imposes costs, and (c) the benefits of early reproduction outweigh the costs was examined for female bison (Bison bison) with data from an 8-year period. Description of ontogenetic patterns indicated that reproductive performance reached a plateau near the end of the growth period; changes with age in fecundity were little related to those of body weight during the typical reproductive lifespan (age 3–18 years). Examination of inter-and intra-individual variation showed that the relationship between growth and reproduction depends on the age of subjects. Larger juveniles matured earlier and were more fecund (though smaller) as adults. In contrast, post-pubertal growth was negatively related to reporductive performance, although intra-individual weight variation was positively associated with pregnancy rate. Fecundity was not generally lower in years after reproduction than after barren years, in spite of weight loss, suggesting that reproduction did not impose significant fitness costs. On the other hand, offspring quality was lower when mothers reproduced in successive rather than alternate years. Early maturation resulted in immediate costs, including reduced growth and infertility in the year after first parturition. However, there were long-term benefits: fecundity in the first 7–9 years was highest for early-maturing and lowest for late-maturing females, suggesting that reproductive success is greater for early-maturing females despite reduced growth. In the present study, trade-offs between growth and reproduction did not appear to reflect substantial costs as measured by long-term reproductive success.

Journal ArticleDOI
TL;DR: The findings suggest that NO is a biologically active transmitter substance in NANC inhibitory neurotransmission and enhanced the open probability of Ca(2+)-activated K+ channels in isolated colonic muscle cells, which may mediate the hyperpolarization response to NANC neurotransmission in colonic muscles.
Abstract: Previous evidence suggests that nonadrenergic, noncholinergic (NANC) inhibitory neurotransmission in visceral muscles may be mediated by nitric oxide (NO). We have demonstrated that NO and the NO carrier S-nitrosocysteine can mimic the hyperpolarization in colonic muscle caused by nerve stimulation. The finding that S-nitrosocysteine breaks down fast enough to cause inhibitory junction potential (IJP)-like hyperpolarizations suggests that NO could be stored as a nitrosothiol in secretory vesicles in nerve terminals. Oxyhemoglobin blocked hyperpolarization responses to NO and S-nitrosocysteine and NANC IJPs. These findings suggest that NO is a biologically active transmitter substance in NANC inhibitory neurotransmission. NO enhanced the open probability of Ca(2+)-activated K+ channels in isolated colonic muscle cells. These channels may mediate the hyperpolarization response to NANC neurotransmission in colonic muscles.

Journal ArticleDOI
TL;DR: In this article, the authors identify specific agents and processes that affected leporid bones in archaeological sites and provide data to distinguish specific agents, processes, and behaviors of leporids.
Abstract: Prehistoric Native Americans hunted leporids (cottontails and hares) for food, clothing, and to obtain raw material for the manufacture of bone tools such as awls. Leporids are also favorite prey of various carnivores and raptors, hence many archaeological sites may contain leporid bones that were deposited by both human and nonhuman activities. This paper provides data to distinguish specific agents and processes that affected leporid bones in archaeological sites. Human behavior tends to create hare tibia diaphysis cylinders, cut-marked bones, unidentifiable burned bone fragments, and assemblages with predominantly adult leporid bone specimens. In contrast, raptor behavior creates more cottontail tibia diaphysis cylinders, bones with beak and talon punctures on only one side, shearing damage principally to innominates and femora, and high frequencies of forelimb and juvenile bones when leporid bones are deposited mainly in raptor pellets.

Journal ArticleDOI
TL;DR: The results show that contextual control over equivalence classes can transfer through equivalence Classes, and the implications of this phenomenon for social stereotyping are discussed.
Abstract: In Experiment 1, subjects acquired conditional equivalence classes controlled by three male and three female names as contextual stimuli. When equivalence relations were tested using new names not used in training (three male and three female), contextual control remained intact. Thus, generalized control of the composition of conditional equivalence classes by characteristically gender-identified names was shown. A basic analysis of this finding was tested in Experiment 2. Contextual equivalence classes were established using as contextual stimuli nonrepresentational visual figures that were members of additional pretrained three-member equivalence classes. When other stimuli in the pretrained equivalence classes were used as contextual stimuli, the conditional equivalence classes remained intact. Control subjects showed that this effect depended on the equivalence relations established in pretraining. The results show that contextual control over equivalence classes can transfer through equivalence classes. The implications of this phenomenon for social stereotyping are discussed.

Journal ArticleDOI
TL;DR: Results are consistent with the following hypothesis: heat stress stimulates the release of maternal antidiuretic hormone or oxytocin, which reduces uterine blood flow and causes a shift in fetal metabolism from anabolic to catabolic pathways; one fetus of heat-stressed twins is more severely affected than its litter mate.

Journal ArticleDOI
TL;DR: It is suggested that a product of the nitric oxide synthetic pathway is involved in NANC neurotransmission in the canine proximal colon.
Abstract: Experiments were performed to determine the involvement of nitric oxide synthase in the generation of nonadrenergic, noncholinergic (NANC) inhibitory junction potentials (IJPs) in the canine proximal colon. Smooth muscle cells were impaled near the myenteric border between the circular and longitudinal layers. Cells exhibited rhythmic myenteric potential oscillations. IJPs were evoked with electrical field stimulation in the presence of drugs to block adrenergic and cholinergic neurotransmission. N omega-nitro-L-arginine, methyl ester (L-NAME), a nitric oxide synthase inhibitor, progressively reduced the amplitude of IJPs. The effect of L-NAME was reversed by L-Arg but not by the stereoisomer D-Arg. IJPs disrupt the regular pattern of myenteric potential oscillations. This effect was also blocked by L-NAME and reversed by L-Arg. These experiments suggest that a product of the nitric oxide synthetic pathway is involved in NANC neurotransmission in the canine proximal colon.

Journal ArticleDOI
TL;DR: In this article, the authors study the relationship between fault segmentation and the complexity of fault geometry and show that there are changes of both geometric pattern and geomorphic character in the area of the segment boundary in the Dixie Valley-Pleasant Valley fault system.

Journal ArticleDOI
TL;DR: Novel aspects of the metabolism of polyunsaturated fatty acids (PUFAs), precursors of prostaglandins and other eicosanoids, in insects are reviewed and showed that it is insect tissue that contains the Δ12 desaturase.

Journal ArticleDOI
TL;DR: The results suggest that dihydropyridine-sensitive Ca2+ currents participate in the plateau potential, and that cholinergic stimulation modulates [Ca2+]cyt and therefore force by regulating the amount of Ca2- entering cells through these channels.
Abstract: Microelectrode techniques and the fluorescent Ca2+ indicator indo-1 were used to measure membrane potential, cytosolic Ca2+ ([Ca2+]cyt), and muscle tension simultaneously in canine antral smooth muscles. Responses of muscles from the myenteric and submucosal regions were compared, since electrical activity and excitation-contraction coupling in these regions differ. The upstroke phase of electrical slow waves in both regions induced an increase in [Ca2+]cyt. In myenteric muscles the plateau phase of slow waves often caused either a further rise in [Ca2+]cyt or maintenance of the level reached during the upstroke event. In submucosal muscles, the plateau phase was significantly smaller and did not induce a second phase in the Ca2+ transient. Contractions were related to the amplitudes of Ca2+ transients. Acetylcholine (ACh; 3 x 10(-8)-10(-6) M) increased the amplitude and duration of the plateau phase of slow waves in a concentration-dependent manner. ACh also increased the second phase of Ca2+ transients and contractile responses associated with the plateau potential. In submucosal muscles ACh induced a significant increase in the plateau phase of the slow wave and increased the corresponding phase of Ca2+ transient. Nicardipine (10(-6) M) inhibited plateau phase of slow waves and the associated increases in [Ca2+]cyt and muscle tension. BAY K 8644 (10(-7) M) augmented the plateau potential and increased [Ca2+]cyt and muscle tension. These results suggest that dihydropyridine-sensitive Ca2+ currents participate in the plateau potential. Cholinergic stimulation modulates [Ca2+]cyt and therefore force by regulating the amount of Ca2+ entering cells through these channels.

Journal ArticleDOI
TL;DR: In this article, the authors examined the relationship between pyrite S and organic C in the modern (Unit 1) sediments of the Black Sea to re-evaluate this suggested relationship.

Journal ArticleDOI
TL;DR: A highly selective Cl- conductance is identified that is regulated by intracellular adenosine 3',5'-cyclic monophosphate, and it appears that this Cl- current may play an important role in the regulation of action potential duration and resting membrane potential.
Abstract: Nonelectrogenic movement of Cl- is believed to be responsible for the active accumulation of intracellular Cl- in cardiac muscle. The electro-neutral pathways underlying this nonpassive distributio...

Journal ArticleDOI
TL;DR: Another physiological role of these enzymes may be to protect from exogenous oxidative stress exerted by dietary redox-active pro-oxidants in the gut, and to the potential of photodynamically mediated oxygen toxicity in peripheral organs such as the integument.

Journal Article
TL;DR: The data demonstrate that the colon circular smooth muscle contains muscarinic receptors of both the M2 and M3 subtypes, which may be coupled to disparate signal transduction pathways important in the physiological actions of acetylcholine in this tissue.
Abstract: The parasympathetic neurotransmitter acetylcholine, acting postsynaptically at the smooth muscle muscarinic receptor, is a principle determinant of colonic motility. In order to elucidate the receptor signal-transduction events responsible for muscarinic receptor-induced contraction of colonic circular smooth muscle, we present here and in the accompanying work studies designed to characterize the muscarinic receptors present in colon and to determine their biochemical coupling. Muscarinic receptor subtypes in canine colonic circular smooth muscle were characterized using radioligand binding techniques. The nonselective muscarinic receptor antagonist radioligand [3H]quinuclidinyl benzilate ([3H]QNB) binds rapidly and reversibly to a single class of saturable sites in colon circular smooth muscle membranes, with an affinity (KD) for the antagonist radioligand of 79.8 +/- 12.6 pM and a density of 123.3 +/- 18.7 fmol/mg of protein. Experiments using membranes prepared from isolated cells purified from the circular smooth muscle layer of canine colon (KD = 102.4 +/- 13.5 pM) confirm the smooth muscle origin of the binding and yield a receptor density of 124,340 receptors/cell. The order of potencies of selective muscarinic receptor antagonists in competition with [3H]QNB for binding to colonic receptors is 4-diphenylacetoxy-N-methylpiperidine methobromide greater than methoctramine greater than AF-DX 116 greater than pirenzepine. Unlike other antagonists tested, pirenzepine competition of [3H]QNB binding is biphasic. The high and low affinities deduced from nonlinear fit of the binding data in colon correlate very well with affinities determined for pirenzepine in mixtures of both submandibular gland (M3) and atrium (M2), indicating the presence of two muscarinic receptor subtypes (82% M2, 18% M3) in colon circular smooth muscle. The muscarinic agonist carbachol binds to both high and low affinity sites in colon, and addition of guanine nucleotide (100 microM GTP gamma S) shifts the agonist competition curve to the right, without eliminating high affinity binding sites. Agonist competition studies with a known ratio of M2 and M3 receptors, obtained by mixing pure M2 and M3 populations, predict the result obtained in colon. cDNA probes specific for each of the muscarinic receptors m1 through m4 were hybridized to colon RNA in a Northern blot analysis. Only m2 and m3 probes hybridized to colon RNA, suggesting the presence of both M2 and M3 receptors. Our data demonstrate that the colon circular smooth muscle contains muscarinic receptors of both the M2 and M3 subtypes, which may be coupled to disparate signal transduction pathways important in the physiological actions of acetylcholine in this tissue.

Journal Article
TL;DR: Percutaneous intra-arterial thrombolysis as the initial treatment for acute lower-limb ischemia markedly reduced the need for urgent surgery, usually simplified the subsequent surgical approach, diminished the overall need for surgery, and often accomplished a successful outcome alone.
Abstract: Acute ischemia of the lower limb remains a significant risk to both life and limb. Mortality rates of approximately 10-30% and amputation rates of the same magnitude in the survivors are repeatedly reported despite advances in medical and surgical techniques. Our experience, which utilized percutaneous intra-arterial thrombolysis as the initial treatment in 72 instances (63 patients), has resulted in a markedly lower mortality rate of 1.6% and a lower amputation rate of 8.5% in the survivors. Careful categorization by clinical degree of ischemia indicates that 82% of the cases were either threatened or irreversible limb ischemia. The initial treatment with thrombolysis did not preclude subsequent prompt surgical treatment when necessary; in these cases, thrombolysis promoted improved surgical results (100%) when it was successful. It markedly reduced the need for urgent surgery, usually simplified the subsequent surgical approach, diminished the overall need for surgery, and often accomplished a successful outcome alone (31%). Significant bleeding was not noted during subsequent surgical procedures and was noted in only 2.8% of the cases. Confirmation of these results and further improvements in technique might justify the use of an initially high-dose urokinase transcatheter infusion regimen as the initial treatment of choice for acute lower-limb ischemia.

Journal ArticleDOI
TL;DR: While maternal condition was correlated with offspring condition, there may be sex differences in investment patterns, Mothers appear better able to influence the condition of daughters than of sons.
Abstract: In polygynous mammals, it may be adaptive for mothers to invest more in sons and/or to adjust the sex ratio of offspring in relation to body condition. Calving patterns were examined over an 8-year period (1982–1989) for a population of Bison bison in which barren females are not selectively culled. From these data, we tested predictions of the sex ratio adjustment hypothesis as well as two assumptions: (1) that offspring weight at the end of the period of parental investment (PI) is correlated with later condition, and (2) that maternal and offspring condition during the period of PI are correlated. In contrast to predictions, there was little evidence that mothers in better condition bear more sons. Short- and long-term measures of maternal condition (previous reproductive status, age, dominance status, pre-pubertal body weight, age at first reproduction, birth date, and the duration of the mother's own suckling period) were little related to offspring sex ratio, although the last calves of old females were nearly always female. Similarly, there was little evidence for sex-biased PI. Weights at about 7 months of age were greater for males than females; males also had somewhat later birth dates, suggesting either longer gestation or later conception. However, maternal reproductive costs, as measured by subsequent fecundity, weight loss, and interbirth intervals, did not vary with calf sex. Both assumptions of the model received some support. However, while maternal condition was correlated with offspring condition, there may be sex differences in investment patterns. Mothers appear better able to influence the condition of daughters than of sons. This sex difference may negate any benefit from male-biased investment.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed time budgets for desert bighorn sheep Ovis canadensis nelsoni in the presence and absence of helicopter overflights at Grand Canyon National Park (GCNP) to determine the extent to which food intake may be impaired.