Reliability and validity of tympanic temperature measurement in persons with high spinal cord injuries

Tympanic temperature measurements in the able bodied have been well studied and validated in previous investigations. This validation has not been studied in individuals with high spinal cord injuries where autonomic control is different above and below the level of the lesion, which makes the accuracy of this measurement for core body temperature questionable. In this correlational study we look at the reliability and validity of tympanic temperature measurement in individuals with high spinal cord injuries in comparison to oral and rectal temperature measures. The rectal measurement proved to be the most reliable with an r value of 0.975 overall. The oral was minimally better than the tympanic with r values of 0.88 and 0.86, respectively. The validity of the oral measure in predicting changes in the rectal temperature (gold standard) was slightly better than the tympanic with r values of 0.88 and 0.77, respectively. Both the oral and tympanic measures accurately reflected changes in the rectal (core) temperature.

Ryanodine receptor-ankyrin interaction regulates internal Ca2+ release in mouse T-lymphoma cells

In this study, we have identified and partially characterized a mouse T-lymphoma ryanodine receptor on a unique type of internal vesicle which bands at the relatively light density of 1.07 g/ml. Analysis of the binding of [3H]ryanodine to these internal vesicles reveals the presence of a single, low affinity binding site with a dissociation constant (Kd) of 200 nM. The second messenger, cyclic ADP-ribose, was found to increase the binding affinity of [3H]ryanodine to its vesicle receptor at least 5-fold (Kd approximately 40 nM). In addition, cADP-ribose appears to be a potent activator of internal Ca2+ release in T-lymphoma cells and is capable of overriding ryanodine-mediated inhibition of internal Ca2+ release. Immunoblot analyses using a monoclonal mouse antiryanodine receptor antibody indicate that mouse T-lymphoma cells contain a 500-kDa polypeptide similar to the ryanodine receptor found in skeletal muscle, cardiac muscle, and brain tissues. Double immunofluorescence staining and laser confocal microscopic analysis show that the ryanodine receptor is preferentially accumulated underneath surface receptor-capped structures. T-lymphoma ryanodine receptor was isolated (with an apparent sedimentation coefficient of 30 S) by extraction of the light density vesicles with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS) in 1 M NaCl followed by sucrose gradient centrifugation. Further analysis indicates that specific, high affinity binding occurs between ankyrin and this 30 S lymphoma ryanodine receptor (Kd = 0.075 nM). Most importantly, the binding of ankyrin to the light density vesicles significantly blocks ryanodine binding and ryanodine-mediated inhibition of internal Ca2+ release. These findings suggest that the cytoskeleton plays a pivotal role in the regulation of ryanodine receptor-mediated internal Ca2+ release during lymphocyte activation.

Ca2+ release channels in rat denervated skeletal muscles

Sarcoplasmic reticulum (SR) Ca2+ release channel-ryanodine receptors (RYR1) from rat fast-twitch skeletal muscle were studied by incorporating heavy sarcoplasmic reticulum membranes into a lipid bilayer. Channels from normal and denervated muscles had the same conductance as that reported for rabbits (about 500 pS) in 250:250 mM cis:trans caesium methanesulphonate. Caffeine (0.1 mM) induced a larger increase in the open probability (Po) in denervated than in normal channels. The caffeine effect was caused by changes in mean open and burst time distributions. Longer opening and burst events were detected in the presence of caffeine. High caffeine concentrations (4 mM) gave similar results in channels from normal and denervated muscles. In denervated muscle, unlike intact muscle, the Ca2+ release channel was not activated at millimolar Ca2+ concentrations; this is similar to the cardiac isoform of the channel. Maximal channel activation was shifted to higher Ca2+ concentrations (pCa 4) and the channel remained activated at millimolar Ca2+ concentrations. The main effect of millimolar Ca2+ concentrations upon Ca2+ release channels from denervated muscles was an increase in the mean open time, with a concomitant increment of the mean burst duration. Alterations in channel gating properties in calcium and caffeine account for changes in the mechanical response after skeletal muscle denervation.

PCR detection of clonal tcr gamma-gene rearrangements in a group of cutaneous T-cell lymphomas including a case of localized pagetoid reticulosis expressing the gamma-delta tcr

In this report, we describe the analysis of clonality performed using a PCR-based approach in a group of cutaneous T-cell lymphomas including a case of localised pagetoid reticulosis expressing the gamma delta T-cell receptor. For our PCR analysis DNA was extracted from frozen tissue of 10 cases of cutaneous T-cell lymphomas and subjected to polymerase chain reaction amplification using primers recognizing conserved sequences of the variable and joining regions of the T-cell receptor gamma chain gene. PCR products were then analyzed by high resolution non-denaturing polyacrylamide gel electrophoresis. Clonal TCR gamma gene rearrangements were detected in all the cases investigated including the case of localised pagetoid reticulosis. The PCR-based approach used in this study may provide an alternative to conventional Southern blot analysis for the analysis of cutaneous T-cell lymphomas as it is easy to perform and requires only minimal amounts of DNA. The findings in localized pagetoid reticulosis are consistent with the proliferation of monoclonal T-cells in lesional skin of this condition and provide evidence for the lymphoproliferative nature of this clinically benign disorder.

Demonstration of a nonmagnetic blazed-grating atomic beam splitter

We demonstrate a coherent atomic beam splitter for metastable helium atoms, based on the diffraction of atomic matter waves from a blazed phase grating. The beam splitter is created by driving the two transitions of a three-level V system with differentially detuned standing light waves that have a relative spatial phase shift of pi/2. The light f ields create a potential that is approximately triangular as a function of position in the laser field. Splittings of 38 times the photon momentum have been observed.

Bleeding injuries in professional football: estimating the risk for HIV transmission

OBJECTIVE

To determine the risk for bleeding injuries in professional football and to estimate the risk for transmission of the human immunodeficiency virus (HIV) through such injuries.

DESIGN

A prospective, observational study.

PARTICIPANTS

Professional football players from 11 teams of the National Football League were observed during 155 regular season games from September through December 1992.

MEASUREMENTS

The frequencies of bleeding injuries were calculated in association with environmental and athletic factors. Using this information, HIV prevalence, and data on transmission of HIV in other circumstances, the risk for transmission of HIV during football games was estimated.

RESULTS

575 bleeding injuries (average, 3.7 per game for each team) involving 538 players (average, 3.5 players on each team per game) were observed. Approximately 88% of the bleeding injuries were abrasions; the remainder were lacerations. Bleeding injuries were markedly more frequent during games played on artificial surfaces, during games played in domed stadiums, and on teams with a final win/loss percentage of 0.500 or lower. Using data on the prevalence of HIV among college men and rates of HIV transmission in the health care setting, the risk for HIV transmission to each player was estimated to be less than 1 per 85 million game contacts.

CONCLUSIONS

Although injuries occur in professional football competitions, bleeding injuries, especially lacerations, occur infrequently. We estimate that the risk for HIV transmission during such competition is extremely remote. The role of artificial playing surfaces on the incidence or severity of bleeding injuries should be investigated.

Genetically engineered antibodies for diagnostic pathology

Antibody genes can be cloned, genetically manipulated, and expressed in both homologous and heterologous expression systems to produce viable antigen-binding proteins complete with natural effector functions. Manipulation of antibody genes permits the expression of fusion proteins or truncated proteins that retain antigen-binding activity. The new antibody technologies are becoming increasingly sophisticated, permitting the alteration of antigen-binding responses, the transfer of antigen specificity between antibodies, and the expression of minimal-size antigen-binding protein domains. These new molecules have been made mostly for studies on function or to provide molecules suited for in vivo diagnosis and therapy; very few have been specifically designed for, or used for, diagnostic histopathology. We describe here the adaptation of small antibody derivatives for use in immunohistochemistry. Molecules suitable for this purpose need only to possess specific antigen-binding ability and some means of detection of antigen-bound material. Detection could be by recognition of a genetically fused flag or tag epitope, by the fusion of an enzyme whose activity can be assayed, or by fusion with a protein that can interact with pre-existing histopathological reagents.

Solvent-dependent influences on skeletal muscle sarcoplasmic reticulum calcium uptake and release

The organic cosolvents propylene glycol (PG) and polyethylene glycol 400 (PEG 400) have previously been shown to differ in their potential to cause muscle damage following im injection. PG was found to be more myotoxic than PEG 400, with indirect implications of the role of cytosolic calcium in mediating this damage. In the present study, the direct effects of these cosolvents were investigated on the sarcoplasmic reticulum (SR), the major intracellular muscle membrane that mobilizes calcium. The passive permeability of isolated SR microsomal vesicles to calcium was not affected by 5.3 and 10.5% (v/v) PG and PEG 400. At 10.5% (v/v), a concentration of the organic cosolvent that would not be unexpected at the injection site, PEG 400 stimulated calcium uptake by 40 and 140% in longitudinal tubular-derived and terminal cisternal-derived vesicles, respectively, without significantly altering the ATP hydrolytic activity of the calcium pump. The calcium pumping efficiency (Ca2+/ATP coupling ratio) was therefore also enhanced. On the other hand, 10.5% (v/v) PG did not significantly alter either calcium uptake or ATPase activity of the pump. PG stimulated calcium efflux from only the terminal cisternae vesicles via a pathway indicative of the ryanodine-sensitive calcium channel, as demonstrated by inhibition of PG-induced efflux by millimolar Mg2+. These results are consistent with multiple interactions of cosolvents with proteins in the membrane bilayer, with the distinction that the two cosolvents differentially influence the calcium pump and release channel, particularly at the terminal cisternae, where there is rapid change of calcium level during excitation-contraction coupling. These data provide further evidence for the role of calcium in mediating organic cosolvent-induced muscle damage. In addition, they provide a possible explanation for the myoprotective effect of PEG 400 (compared to PG) as a result of increased myoplasmic calcium removal and reduced calcium release.

Stereospecificity of (+)-pinoresinol and (+)-lariciresinol reductases from Forsythia intermedia

Pinoresinol/lariciresinol reductase catalyzes the first known example of a highly unusual benzylic ether reduction in plants; its mechanism of hydride transfer is described. The enzyme was found in Forsythia intermedia and catalyzes the presumed regulatory branch-points in the pathway leading to benzylaryltetrahydrofuran, dibenzylbutane, dibenzylbutyrolactone, and aryltetrahydronaphthalene lignans. Using [7,7'-2H2]-pinoresinol and [7,7'-2H3]lariciresinol as substrates, the hydride transfers of the highly unusual reductase were demonstrated to be completely stereospecific (> 99%). The incoming hydrides were found to take up the pro-R position at C-7' (and/or C-7) in lariciresinol and secoisolariciresinol, thereby eliminating the possibility of random hydride delivery to a planar quinone methide intermediate. As might be expected, the mode of hydride abstraction from NADPH was also stereospecific: using [4R-3H] and [4S-3H]NADPH, it was found that only the 4 pro-R hydrogen was abstracted for enzymatic hydride transfer.

In situ Ca(2+)-induced Ca2+ release from a ryanodine-sensitive intracellular Ca2+ store in corneal epithelial cells

1. In a number of tissues, Ca2+ signaling involves Ca(2+)-induced Ca2+ release (CICR) from ryanodine- and caffeine-sensitive intracellular Ca2+ stores. We sought evidence for such a mechanism in bovine corneal epithelial cells (BCE). 2. We have identified a microsomal fraction of BCE which possesses high-affinity [3H]-ryanodine binding sites indicating the presence of the ryanodine receptor Ca2+ channel. 3. Functional evidence for CICR is that in fura-2 loaded BCE the magnitude of Ca2+ transients induced by the addition of either the adenylate cyclase activator, forskolin, or the L-type Ca2+ channel agonist, BAY-K 8644, were both enhanced by preincubation with 5 microM ryanodine. This ryanodine enhancement provides evidence that Ca2+ release from a ryanodine-sensitive intracellular Ca2+ store also contributes to the Ca2+ transients. Therefore, Ca(2+)-induced Ca2+ release is a component of Ca2+ signaling in BCE.

Cytoplasmic Ca2+ does not inhibit the cardiac muscle sarcoplasmic reticulum ryanodine receptor Ca2+ channel, although Ca(2+)-induced Ca2+ inactivation of Ca2+ release is observed in native vesicles

Single channel properties of cardiac and fast-twitch skeletal muscle sarcoplasmic reticulum (SR) release channels were compared in a planar bilayer by fusing SR membranes in a Cs(+)-conducting medium. We found that the pharmacology, Cs+ conductance and selectivity to monovalent and divalent cations of the two channels were similar. The cardiac SR channel exhibited multiple kinetic states. The open and closed lifetimes were not altered from a range of 10(-7) to 10(-3) M Ca2+, but the proportion of closed and open states shifted to shorter closings and openings, respectively. However, while the single channel activity of the skeletal SR channel was activated and inactivated by micromolar and millimolar Ca2+, respectively, the cardiac SR channel remained activated in the presence of high [Ca2+]. In correlation to these studies, [3H]ryanodine binding by the receptors of the two channel receptors was inhibited by high [Ca2+] in skeletal but not in cardiac membranes in the presence of adenine nucleotides. There is, however, a minor inhibition of [3H]ryanodine binding of cardiac SR at millimolar Ca2+ in the absence of adenine nucleotides. When Ca(2+)-induced Ca2+ release was examined from preloaded native SR vesicles, the release rates followed a normal biphasic curve, with Ca(2+)-induced inactivation at high [Ca2+] for both cardiac and skeletal SR. Our data suggest that the molecular basis of regulation of the SR Ca2+ release channel in cardiac and skeletal muscle is different, and that the cardiac SR channel isoform lacks a Ca(2+)-inactivated site.

Cyclic ADP-ribose as an endogenous regulator of the non-skeletal type ryanodine receptor Ca2+ channel

The skeletal and cardiac isoforms of the ryanodine receptor Ca2+ channel (RyRC) constitute the Ca2+ release pathway in sarcoplasmic reticulum of skeletal and cardiac muscles, respectively. A direct mechanical and a Ca(2+)-triggered mechanism (Ca(2+)-induced Ca2+ release) have been respectively proposed to explain the in situ activation of Ca2+ release in skeletal and cardiac muscle. In non-muscle cells, however, where the RyRC also participates in Ca2+ signalling, the mechanism of RyRC activation is unknown. Cyclic adenosine 5'-diphosphoribose (cADPR), which is present in many mammalian tissues, has been reported to induce Ca2+ release from ryanodine-sensitive intracellular Ca2+ stores in sea urchin eggs. Here we provide evidence that cADPR directly activates the cardiac but not the skeletal isoform of the RyRC. This, together with results on sea urchin eggs, suggests that cADPR is an endogenous activator of the non-skeletal type of RyRC and may thus have a role similar to inositol 1,4,5-trisphosphate in Ca2+ signalling.

Conflicting measurements of depression in a substance abuse population

Methadone maintenance patients (N = 217) were administered a computerized screening version of the National Institute for Mental Health (NIMH) Diagnostic Interview Schedule (DIS), the Beck Depression Inventory (BDI) and the Addiction Severity Index (ASI) 2-4 weeks after treatment entry. Few differences were found between African-American, Hispanic, and Caucasian subjects. Only 1.7% of the patients met a lifetime diagnosis of major depressive disorder, and 1.4% qualified for a current diagnosis major depressive disorder. In contrast, 35.8% of the patients reported moderate to serious depression on the BDI during the previous week, and 19.3% reported serious depression during the previous month on the ASI (38.7% lifetime depression). Because moderate correlations were found between the DIS, the BDI, and the ASI measures of depression, there is some indication that they were tapping a similar construct. Therefore the lower rates of depression found with the DIS are probably attributable to its more stringent definition of depression. The findings tend to confirm previous literature indicating that the DIS, as contrasted with other structured psychiatric interviews, underestimates depression.

Sample design: Third National Health and Nutrition Examination Survey

This report presents a detailed description of the sample design for the Third National Health and Nutrition Examination Survey, 1988-94, including a brief description of research that led to the choice of the final design. The National Health and Nutrition Examination Survey (NHANES) is one of the major surveys of the National Center for Health Statistics, Centers for Disease Control. Information on the health and nutritional status of the noninstitutionalized population of the United States is collected through the NHANES household interviews and standardized physical examinations.

Second opinion programs: continued savings from nonconfirmed surgeries

A second opinion program for elective surgery was one of the first tools utilized by employers to "manage" health care costs. These authors argue that second opinion programs continue to demonstrate their usefulness as part of overall health care cost-management effort.

Esthesioneuroblastoma presenting as sudden unilateral blindness. Histopathologic confirmation of optic nerve demyelination

We report here a case of esthesioneuroblastoma an 11-year-old girl presenting as acute loss of vision with minimal evidence of orbital, nasal, or paranasal sinus disease, a rare presenting symptom for this tumor. The initial diagnosis was postviral optic neuritis, a pattern of presentation not previously reported. When vision failed to improve, magnetic resonance imaging revealed a lesion in the posterior ethmoid and sphenoid sinuses. After a biopsy, the tumor was excised through the cranium and paranasal sinuses. A mass completely surrounding the optic nerve without invasion was found. Histochemical staining suggested demyelination secondary to compression, confirming the clinical impression of optic neuritis. Anti-Leu 7 monoclonal antibody is useful in characterizing of this tumor, since other immunochemical stains can be misleading. Radiation and chemotherapy were given after the tumor was removed. Two years later, the patient has had neither recurrence nor complications.

Hematological indices in a cohort of HTLV-I/II and HIV-1 infected intravenous drug users in New York City

The prevalence and clinical consequences of human T-cell lymphotropic viruses types I and II (HTLV-I/II) infection in human immunodeficiency virus-1 (HIV-1) infected persons are areas of continuing interest. This article reports the preliminary findings of the hematological indices in 454 patients infected with HIV-1 and HTLV-I/HTLV-II. Based on serology, 46.2% of the patients had evidence of HIV-1 infection only, 4.6% had evidence of HTLV-I/II only, 14.3% had evidence of both HIV-1 and HTLV-I/II, and 34.8% had evidence of neither HIV-1 or HTLV-I/II. The patient group with both HTLV-I/II and HIV-1 infection had lower total white blood cell, platelet, and serum hematocrits than patients with either HIV-1 or HTLV-I/II infection. While these differences were insignificant, they do not suggest any HTLV-I/II-induced protective effect against HIV-1 related hematological consequences.

Brown tumor and secondary hyperparathyroidism

Brown tumor is a focal, bony lesion of hyperparathyroidism that results from parathyroid hormone on bone increasing osteoclastic activity with bone resorption and trabecular fibrosis. This leads to microfractures and hemorrhage and the appearance of brown tumors, which are seen most commonly in primary hyperparathyroidism and less frequently in secondary hyperparathyroidism. Rarely do these tumors involve the orbit. We report the sixth case, to our knowledge, of orbital involvement, in a patient with chronic renal failure (secondary hyperparathyroidism) and review the literature.

Effects of inhibition of nitric oxide formation on basal vasomotion and endothelium-dependent responses of the coronary arteries in awake dogs

The role of nitric oxide in basal vasomotor tone and stimulated endothelium-dependent dilations in the coronary arteries in chronically instrumented awake dogs was studied by examining the consequences of inhibiting endogenous nitric oxide formation with the specific inhibitor of nitric oxide formation, NG-monomethyl-L-arginine (L-NMMA). In four awake dogs, coronary dimension crystals were chronically implanted on the circumflex artery for the measurement of epicardial coronary diameter, and Doppler flow probes were implanted for quantitation of phasic coronary blood flow (vasomotion of distal regulatory resistance vessels). Basal epicardial coronary diameter, acetylcholine-stimulated endothelium-dependent dilation, and flow-induced endothelium-dependent dilation of the epicardial arteries and phasic blood flow were recorded before, and after 5, 15, 50, and 120 mg/kg of L-NMMA. L-NMMA induced a dose-related increase in basal epicardial coronary vasomotor tone. There was an accompanying increase in aortic pressure and a decrease in heart rate. At doses greater than or equal to 50 mg/kg, rest phasic coronary blood flow was also decreased. Left ventricular end-diastolic pressure and contractility were not significantly changed. In contrast, the flow-induced or acetylcholine-stimulated endothelium-dependent responses were attenuated only after infusion of the highest does of L-NMMA (120 mg/kg). The changes in the basal vasomotor tone and acetylcholine-stimulated endothelium-dependent responses returned towards the control states in the presence of L-arginine (660 mg/kg). These data support the view that nitric oxide plays a significant role in modulating basal vasomotion and endothelial-dependent dilation stimulated by acetylcholine or increase in blood flow in epicardial coronary arteries and also influence the regulation of coronary blood flow during physiologic conditions.

Phosphatidylinositol 4,5-bisphosphate-induced Ca2+ release from skeletal muscle sarcoplasmic reticulum terminal cisternal membranes. Ca2+ flux and single channel studies

We report here that the inositol 1,4,5-trisphosphate (IP3) precursor, L-alpha-phosphatidylinositol 4,5-bisphosphate (PIP2) is a potent molecule (1 microM) which activates the ryanodine-sensitive Ca2+ release channel from rabbit skeletal muscle terminal cisternae incorporated into a phospholipid bilayer. It also stimulates Ca2+ release from these membrane vesicles. Therefore, it may play a modulating role in excitation-contraction coupling. In the bilayer, PIP2 added on the cytoplasmic side increased the mean channel opening probability 2-12-fold in the presence and absence of physiological Mg2+ and ATP. From flux studies, PIP2-induced Ca2+ release, occurring through the ryanodine-sensitive Ca2+ release channel, displayed saturation kinetics. The rate of Ca2+ release induced by PIP2 was approximately greater than 50% slower than the rates induced by other agents (e.g. caffeine, Ca2+, ATP). PIP2, and not IP3, effectively elicited Ca2+ release from terminal cisternae. On the contrary, IP3, and not PIP2, specifically mediated Ca2+ release from dog brain cerebellum microsomes, where IP3 receptors are known to be found. The PIP2-induced Ca2+ release from muscle membranes was not dependent on medium [Ca2+] (from less than 10(-9) to approximately 10(-4) M). However, IP3 could activate the terminal cisternae Ca2+ channel in the bilayer when there was low Ca2+ (less than 10(-7) M). The data suggest that the ionic microenvironment around the Ca2+ channel may be different for observing the two phosphoinositide actions.

Seroepidemiology and clinical aspects of human T-cell lymphotropic virus type I/II infection in a cohort of intravenous drug users in New York City

To define further the magnitude, epidemiology, and clinical features of human T-cell lymphotropic/leukemia virus type I/II (HTLV-I/II) infection in 454 intravenous drug users in New York City, we evaluated previously frozen aliquots of sera for HTLV-I/II antibodies using enzyme-linked immunoassay, Western blot, and radioimmunoprecipitation techniques. We found HTLV-I/II infection in 18.9% of the subjects. Age (p = 0.001), race (p = 0.001), having a same gender sexual relationship (p = 0.01), and HIV-1 infection (p = 0.041) were clear correlates of HTLV-I/II infection. HTLV-I/II seropositive subjects, in contrast to seronegative subjects, had lower leukocyte counts (p = 0.05) and higher globulin (p = 0.005) and gamma globulin (p = 0.009) levels even when HIV-1 serostatus was controlled. The considerable prevalence of HTLV-I/II infection and the morbidity of HTLV-I/II-associated disorders strongly suggest a continued need to define the dimensions of HTLV-I/II infection.

Surgical treatment of thyroid-related lid retraction: a new variation

We describe a cutaneous approach for retraction of the upper eyelid which incorporates a levator aponeurotic/Mueller's muscle recession with maintenance of the normal orbital septum levator aponeurosis anatomy. With success defined as asymmetry between the two eyelids of 1 mm or less, with a marginal reflex distance as close to 4 mm as possible, this technique was successful in 87% of 15 consecutive patients. All patients reported improved comfort. This approach is quick and easy, bleeding is minimal, height and contour are predictable, the upper eyelid crease is preserved, and spacers are avoided, with less postoperative eyelid thickening and reaction.

Patterns of HIV-1 and HTLV-I/II in intravenous drug abusers from the middle atlantic and central regions of the USA

Seroprevalence of human immunodeficiency virus type 1 (HIV-1) and human T lymphotropic virus types I and II (HTLV-I/II) was determined among 1160 intravenous (iv) drug abusers from five drug treatment or medical centers (Manhattan, Brooklyn, New Jersey, Detroit, and New Orleans). HIV-1 infection ranged from 5% in New Orleans to 48% in New York City. Hispanics and blacks had a significantly higher rate of HIV-1 infection than whites (P less than .01), but within each group rates were similar between males and females and by age stratum. HTLV-I/II seroprevalence increased with age from 3% in the 20-29 year age group to 37% in the group greater than 50 years. New Orleans and Manhattan (24%) had the highest rate, and blacks (19%) had a higher rate than either Hispanics (6.3%) or whites (7.3%). No association between HIV-1 and HTLV-I/II infection was observed except in Manhattan. When compared with iv drug abusers infected only with HIV-1, dually infected subjects had more clinical symptoms related to immune deficiency but a lower prevalence of HIV antigenemia. These data document the frequent occurrence of retroviral infections in iv drug abusers. The contrast between the two classes of virus suggests that HIV-1 is more efficiently transmitted, while the age-dependent rise in HTLV-I/II seroprevalence suggests cumulative exposure of a less-transmissible agent.

Gibberellin structure and florigenic activity in Lolium temulentum, a long-day plant

Structural requirements for florigenic activity among gibberellins (GAs) and GA derivatives, including several new ones, applied once to leaves of Lolium temulentum, were examined. The compounds were applied to plants kept either in non-inductive short days (SD) or exposed to one inductive long day (LD). Inflorescence initiation and stem-elongation responses were assessed three weeks later. Among the GAs used, the range in effective dose for inflorescence initiation was more than 1000-fold, but substantially less for stem elongation. Some GAs promoted both stem elongation and inflorescence initiation, some promoted one without the other, and some affected neither. The structural features enhancing florigenic activity were often different from those enhancing stem elongation. Except in the case of 2,2-dimethyl GA4, a double bond in the A ring at either C-1,2 or C-2,3 was essential for high florigenic activity, though not for stem elongation. A free carboxy group was needed for both. Inflorescence initiation in Lolium was enhanced by hydroxylation at C-12, -13 and -15, whereas hydroxylation at C-3 reduced the effect on inflorescence initiation but increased that on stem elongation. A 12β-hydroxyl was more effective than the α epimer for inflorescence initiation whereas the reverse was true for stem elongation. Although such differential effectiveness of GAs for inflorescence initiation and for stem elongation could reflect differences in uptake, transport or metabolism, we suggest that it is indicative of specific structural requirements for inflorescence initiation.

Preferential proximal coronary dilation by activators of guanylate cyclase in awake dogs

The vasodilation effects of activators of guanylate cyclase, atrial natriuretic peptide (ANP), nitroglycerin (NTG), and acetylcholine (ACh), on the epicardial conductance arteries and the distal resistance coronary vessels were examined in chronically instrumented awake dogs and related serially to plasma guanosine 3',5'-cyclic monophosphate (cGMP) levels. Left atrial bolus injections of ANP (3 micrograms/kg; n = 7), NTG (13 micrograms/kg; n = 7), or ACh (0.13 micrograms/kg; n = 3) induced sustained increases in epicardial coronary dimension (ultrasonic crystals), 3.3, 5.7, and 6.7%, respectively, lasting greater than 40 min for ANP and NTG and greater than 3 min for ACh, and relatively brief increases in blood flow (resistance artery vasomotion) for each agent. Plasma samples withdrawn serially after injections of each agent demonstrated that only ANP increased cGMP level; the time course of ANP-induced epicardial vasodilation followed more closely the increase in cGMP than that of plasma ANP. These data demonstrated that these three activators of guanylate cyclase induced preferential sustained epicardial vasodilation and only brief distal coronary vasodilation with minor or no change in systemic hemodynamics. The prolonged increase in plasma cGMP after ANP injection suggested continuous cGMP production during ANP-induced proximal vasodilation. These data demonstrate a striking heterogeneity of vasomotor responses in the coronary arterial vasculature and suggest that cGMP-mediated vasodilation mechanisms are more predominant in proximal conductance arteries compared with distal resistance vessels.

Somatosensory evoked potentials and magnetic resonance imaging in syringomyelia

Somatosensory evoked potentials (SEPs) to median and posterior tibial stimulation were obtained in 22 patients with syringomyelia. All patients had magnetic resonance imaging (MR) which defined the maximum transverse diameter of the syrinx as well as its longitudinal extension. SEP was abnormal in 16 (72%) patients. Median and posterior tibial SEPs were abnormal in 11 and 15 patients respectively. Both tests were abnormal in 10 patients. Ten patients showed absence of one or more central potentials (P/N13, N20, N22) and 7 patients demonstrated increased conduction times (N9-N20, P/N13-N20, N22-P40). The mean maximum transverse diameter of the syrinx was 7.5 mm in patients with normal SEPs and 16.2 mm in patients with abnormal SEPs. Abnormal SEP was observed in all 5 patients with loss of position sense, in 9 of 13 (69%) with loss of superficial pain and temperature, and 1 of 2 patients with motor deficit only. Central SEP abnormalities were observed in 3 of 5 patients with sensory deficits indistinguishable from a peripheral neuropathy and in 2 patients in the asymptomatic extremity. Three of 4 patients with syringomyelia and Chiari malformation had a normal SEP.

Specific association of calmodulin-dependent protein kinase and related substrates with the junctional sarcoplasmic reticulum of skeletal muscle

A systematic study of protein kinase activity and phosphorylation of membrane proteins by ATP was carried out with vesicular fragments of longitudinal tubules (light SR) and junctional terminal cisternae (JTC) derived from skeletal muscle sarcoplasmic reticulum (SR). Following incubation of JTC with ATP, a 170,000-Da glycoprotein, a 97,500-Da protein (glycogen phosphorylase), and a 55,000-60,000-Da doublet (containing calmodulin-dependent protein kinase subunit) underwent phosphorylation. Addition of calmodulin in the presence of Ca2+ (with no added protein kinase) produced a 10-fold increase of phosphorylation involving numerous JTC proteins, including the large (approximately 450,000 Da) ryanodine receptor protein. Calmodulin-dependent phosphorylation of the ryanodine receptor protein was unambiguously demonstrated by Western blot analysis. The specificity of these findings was demonstrated by much lower levels of calmodulin-dependent phosphorylation in light SR as compared to JTC, and by much lower cyclic AMP dependent kinase activity in both JTC and light SR. These observations indicate that the purified JTC contain membrane-bound calmodulin-dependent protein kinase that undergoes autophosphorylation and catalyzes phosphorylation of various membrane proteins. Protein dephosphorylation was very slow in the absence of added phosphatases, but was accelerated by the addition of phosphatase 1 and 2A (catalytic subunit) in the absence of Ca2+, and calcineurin in the presence of Ca2+. Therefore, in the muscle fiber, dephosphorylation of SR proteins relies on cytoplasmic phosphatases. No significant effect of protein phosphorylation was detected on the Ca2(+)-induced Ca2+ release exhibited by isolated JTC vesicles. However, the selective and prominent association of calmodulin-dependent protein kinase and related substrates with junctional membranes, its Ca2+ sensitivity, and its close proximity to the ryanodine and dihydropyridine receptor Ca2+ channels suggest that this phosphorylation system is involved in regulation of functions linked to these structures.

Ischemia-induced epicardial vasoconstriction. A potential mechanism for distant myocardial ischemia

This study evaluated the effects of transient coronary occlusion on the diameter of a nonischemic vessel or a nonischemic coronary segment proximal to the site of occlusion. Awake mongrel dogs chronically instrumented with dimension crystals, Doppler flow probes, and distal pneumatic occluders on the circumflex coronary arteries were subjected to transient 2-minute circumflex occlusions (n = 9) under constant heart rate (120 beats/min). Left ventricular end-diastolic pressure increased by 60% (from 10 +/- 1 to 16 +/- 2 mm Hg), and dP/dt decreased by 8% (from 2,048 +/- 130 to 1,885 +/- 110 mm Hg/sec); systemic hemodynamics were unaltered. Epicardial coronary diameter proximal to the site of occlusion decreased by 4.37% (from 3.62 +/- 0.25 to 3.46 +/- 0.29 mm, p less than 0.05). Constriction began 15-20 seconds after the onset of ischemia and progressed to maximum in 1-2 minutes. Combined alpha- and beta-receptor blockade (n = 8) with phentolamine (2 mg/kg) and propranolol (1 mg/kg) or cyclooxygenase inhibition (n = 5) with indomethacin (7.5 mg/kg) did not attenuate the ischemia-induced vasoconstriction response. Transient 2-minute occlusion of the left anterior descending coronary artery (n = 6) also elicited significant epicardial vasoconstriction in the circumflex coronary artery in the first minute (from 3.88 +/- 0.31 to 3.81 +/- 0.31 mm, p less than 0.05); the constriction was attenuated subsequently by an increase (25.5%) in circumflex flow. When left anterior descending occlusion was repeated (n = 6) with circumflex flow held constant, the ischemia-induced circumflex constriction was augmented; diameter decreased 3.7% (from 3.83 +/- 0.29 to 3.69 +/- 0.29 mm, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokine production in the rheumatoid joint: implications for treatment

Cytokines are protein mediators that play a part in inflammation, the immune response, cell growth, repair, and fibrosis. All of these are continuing processes in active rheumatoid arthritis (RA), and so it would be expected that many cytokines would be actively produced in RA joints. Here, the molecular strategies devised to study the possible role of cytokines in the pathogenesis of RA, are reviewed and some of the initial results described. The relative abundance of various cytokines is 'catalogued' and then attention is turned to an attempt to discover which cytokines are of major importance in the pathogenesis. Neutralising antibodies to cytokines were used for that purpose, and it was found that tumour necrosis factor alpha (TNF alpha) is one of the major signals regulating the production of interleukin-1 in the RA, but not in the osteoarthritic joint. To understand further the dynamics of the cytokine network localisation of the cytokine producing cells by immunostaining--for example, TNF alpha, is currently being established.

Ryanodine as a probe for the functional state of the skeletal muscle sarcoplasmic reticulum calcium release channel

In this paper, we study the modulation of the rabbit fast twitch skeletal muscle calcium release channel by assaying the kinetics of [3H]ryanodine binding, 45Ca2+ flux, and single-channel activity. The effects of modulators of the Ca2+ release channel (confirmed here with both flux and single-channel data) were examined for effects on [3H]ryanodine binding to terminal cisternae vesicles. We find that activators of the release channel, such as adenine nucleotides (1 mM) and caffeine (1 mM), enhance the rate of association of [3H]ryanodine, whereas inhibitors, such as Mg2+ (1 mM) and ruthenium red (100 nM), decrease the rate of association. High concentrations of either ryanodine or ruthenium red, which close the channel, slow the dissociation of [3H]ryanodine, suggesting that at these concentrations the inhibitory effects of both ryanodine and ruthenium red occur as the result of binding at a site distinct from but interacting cooperatively with the high affinity site. Our data are consistent with a model in which the high affinity ryanodine binding site is within a conformationally sensitive area of the channel, such that conditions that open the channel (ATP, caffeine, etc.) enhance the rate at which [3H]ryanodine reaches its binding site and other conditions that close the channel (the binding of ryanodine and ruthenium red to a low affinity site) slow the dissociation of [3H]ryanodine from the high affinity site. Some conditions that inhibit channel activity (high concentrations of Mg2+ and Ca2+) slow association but do not affect dissociation of bound [3H]ryanodine, suggesting a completely different state of the channel from that which is inactive in the presence of high concentrations of ryanodine or ruthenium red. In summary, the functional state of the fast twitch skeletal muscle calcium release channel can be characterized by the changes in the kinetics of [3H]ryanodine binding. Different modulators (activators/inhibitors) affect different aspects of ryanodine binding (association/dissociation).

Nitric oxide modulates epicardial coronary basal vasomotor tone in awake dogs

This study evaluates the role of endogenous nitric oxide in the modulation of basal coronary vasomotor tone by studying the effects of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide formation from L-arginine, on resting epicardial coronary diameter and coronary flow. L-NMMA (5 mg/kg) was infused in seven awake dogs chronically instrumented with coronary dimension crystals for measurement of epicardial coronary diameter, and Doppler flow probes for quantitation of phasic coronary flow (vasomotion of distal regulatory resistance coronary vessels). Epicardial coronary diameter decreased 5.5% from 3.47 +/- 0.17 to 3.28 +/- 0.15 mm (mean +/- SE). The diameter change was gradual, reaching a maximum at 13 +/- 2 min after infusion, and persistent, lasting greater than 90 min. Phasic coronary flow did not change. Mean aortic pressure significantly increased from 99 +/- 3 to 111 +/- 3 mmHg and heart rate decreased from 56 +/- 4 to 46 +/- 3 beats/min. Left ventricular end-diastolic pressure and contractility were not significantly altered. L-Arginine (66 mg/kg) but not D-arginine reversed all hemodynamic parameters. These data support an important role of nitric oxide in modulating basal epicardial coronary vasomotor tone and systemic vascular resistance.

Effects of atrial natriuretic peptide on the coronary arterial vasculature in humans

The effects of the synthetic 28-amino-acid alpha-human atrial natriuretic peptide (ANP) on the proximal coronary arteries and coronary blood flow were evaluated in 17 patients. Proximal coronary dimension was quantitated by digital angiography, and coronary flow was quantitated with 3F Doppler flow catheters. ANP, when given as a 2.5-micrograms/kg bolus in the left ventricle, caused sustained significant proximal coronary dilations from 3.49 +/- 0.57 to 4.09 +/- 0.76 mm, lasting more than 30 minutes. The proximal coronary diameter did not increase further after intracoronary injection of 0.3 mg nitroglycerin (4.08 +/- 0.79 mm). Coronary flow (resistance coronary dilation) was not significantly increased at 5 minutes after ANP (87 +/- 55 to 102 +/- 54 vol flow units), indicating that the proximal coronary dilations were not flow dependent. The persistent proximal coronary dilations were associated with minor and transient decreases in aortic pressure and left ventricular end-diastolic pressure and with minor and transient increases in heart rate, cardiac output, and left ventricular contractility. Plasma ANP level increased significantly by more than sixfold from 39.8 +/- 8.8 to 245.8 +/- 168.5 pg/ml. The time course of proximal coronary dilations was related more closely to the time course of increase in plasma cyclic guanosine monophosphate than that of plasma ANP. This study demonstrates that bolus injection of ANP (2.5 micrograms/kg), an endogenous vasodilator, caused marked sustained preferential proximal coronary dilations and brief minor changes in cardiac and systemic hemodynamics. Although additional studies are needed to assess its clinical efficacy as a coronary dilator in the treatment of coronary artery disease, these data suggest a potential of ANP in the therapy of ischemia.

Effects of a stabilized endothelium-derived relaxing factor on the coronary vasculature in awake dogs

The effects of a partially purified endothelium-derived relaxing factor (EDRF) stabilized by acidification from cultured bovine aortic endothelial cells stimulated with the calcium ionophore A23187 on coronary and peripheral vasculature were examined in five awake dogs. The dogs were chronically instrumented with miniature arterial dimension crystals and Doppler flow probes. Intracoronary or intra-arterial infusions of this EDRF induced a rapid (less than 15 s) significant increase in the proximal vessel diameter (P less than 0.02). The duration of proximal dilation response to this EDRF persisted up to 6 min, whereas the smaller changes in distal flow were more transient (less than 1 min). Similar but more pronounced changes in the proximal arterial dilation and distal flow occurred with infusion of nitroglycerin (0.4 mg). No vasoactive changes were observed during infusions of the control vehicle. The vasodilatory effects to this EDRF occurred in the absence of changes in aortic and left ventricular pressure, rate of pressure development (dP/dt), and heart rate. These data demonstrate that infusion of this partially purified relaxing factor from cultured endothelial cells causes vasodilation in vivo with a vasoactive profile similar to nitroglycerin. The biological effects of this EDRF persist significantly longer than the extreme lability of EDRF at neutral pH (approximately 6 s), consistent with its in vitro effects. Despite the demonstration of rapid inactivation of EDRF in vitro by hemoglobin, high oxygen tension, and plasma, the study shows that this EDRF can have significant in vivo vasoactive effects.

Primary intraosseous hemangioma of the orbit. Report of a case and review of literature

Orbital intraosseous hemangiomas are rare entities, with only 15 previously reported. We review these and present our own. They are benign, vascular tumors, typically found in the frontal, ethmoid, or zygomatic bones. They tend to present in the 4th or 5th decades as a mildly painful orbital rim mass. Ocular findings may be absent or severe, including blindness. These tumors have characteristic, although not always present, roentgenologic features that differentiate them. Our case is unusual in that it is the oldest patient reported, demonstrates bilateral lesions, and did not exhibit classic x-ray findings. We report imaging these lesions with magnetic resonance imaging with nonspecific results. The pathology of orbital hemangiomas is presented, with the most common being the cavernous type. Because these tumors may bleed when entered, block excision with normal margins is the treatment of choice. Radiation therapy has specific indications for nonresectable lesions. Prognosis is uniformly good, if treated.

Gunshot wounds of the eye and orbit

Gunshot wounds to the globe and orbit require careful evaluation and management. This article highlights five cases of penetrating gunshot injuries, each demonstrating different points to consider when managing the severely traumatized patient. Immediate and late complications are described. Missile velocities of different weapons are detailed, and the mechanism of injury is discussed. Careful preoperative evaluation is stressed as a means of avoiding complications.

Human immunodeficiency virus infection in a cohort of intravenous drug users in New York City. Demographic, behavioral, and clinical features

In 1985, 454 intravenous drug users were recruited from among patients scheduled for physical examination in methadone treatment clinics in New York City. A questionnaire was administered, and serum was collected for human immunodeficiency virus (HIV) serology. The HIV seroinfection rate was 60.6%, with antibody and antigen detected in 58.4% and 4.3%, respectively, of the population. Nineteen percent of 307 subjects were in Group III or Group IV of the Centers for Disease Control (CDC) classification system for HIV-associated infections. Only behavioral factors (p = 0.001) and clinical indicators (p = 0.003) were found to distinguish the HIV-infected from the non-infected subjects. Frequent use of intravenous drugs (p = 0.016), duration of drug use (p = 0.050), and duration of drug treatment enrollment (p = 0.038) were significantly associated with HIV seroinfection status and CDC stage of HIV disease. These findings strongly support aggressive efforts to reduce parenteral drug use and enroll intravenous drug users into effective drug treatment programs.

Antibodies to junctional sarcoplasmic reticulum proteins: probes for the Ca2+-release channel

The junctional face membrane plays a key role in excitation-contraction coupling in skeletal muscle. A protein of 350 kDa, tentatively identified as a component of the junctional feet, connects transverse tubules to terminal cisternae of sarcoplasmic reticulum [Kawamoto, Brunschwig, Kim & Caswell (1986) J. Cell Biol. 103, 1405-1414]. The membrane topology and protein composition of sarcoplasmic reticulum Ca2+-release channels of rabbit skeletal muscle were investigated using an immunological approach, with anti-(junctional face membrane) and anti-(350 kDa protein) polyclonal antibodies. Upon preincubation of the terminal cisternae with anti-(junctional face membrane) antibodies, Ca2+-ATPase and Ca2+-loading activities were not affected, whereas anti-(350 kDa protein) antibodies stimulated Ca2+-ATPase activity by 25% and inhibited Ca2+-loading activity by 50% (at an antibody/terminal cisternae protein ratio of 1:1). Specific photolabelling of terminal cisternae proteins with [14C]doxorubicin was prevented by both anti-(junctional face membrane) and anti-(350 kDa protein) antibodies. Stimulation of Ca2+ release by doxorubicin was prevented by both anti-(junctional face membrane) and anti-(350 kDa protein) antibodies. Half-maximal inhibition was obtained at an antibody/terminal cisternae protein ratio of 1:1. Kinetic measurements of Ca2+ release indicated that anti-(350 kDa protein) antibodies prevented Ca2+-induced Ca2+ release, whereas the ATP-stimulation and the inhibition by Mg2+ were not affected. These results suggest that: (i) Ca2+- and doxorubicin-induced Ca2+ release is mediated by Ca2+ channels which are selectively localized in the junctional face membrane; (ii) the 350 kDa protein is a component of the Ca2+-release channel in native terminal cisternae vesicles; and (iii) the Ca2+-activating site of the channel is separate from other allosteric sites.

Reperfusion alters the relation between blood flow and the remaining myocardial infarction

This study evaluated whether or not reperfusion of ischemic myocardium 2 hours after occlusion alters the basic relation between myocardial blood flow and infarction occurring during permanent occlusion. Awake mongrel dogs chronically instrumented with proximal circumflex coronary occluders were subjected to permanent occlusion (group A, n = 10) or occlusion followed by reperfusion 2 hours later (group B, n = 11). Myocardial blood flow was quantified with radioactive microsphere injections before, 6 hours after occlusion (group A), immediately before release, and 4 hours after reperfusion (group B). Three days later, the dogs were killed, and the heart was sectioned systematically into approximately 80 1-2-g circumferential and transmural samples for radioactive counting and histologic infarct quantification. Epimyocardial and endomyocardial samples from the permanent occlusion group (A) and the reperfused group (B) were separated by infarct range and related to regional myocardial blood flow measurements. In groups A and B, regional myocardial blood flow in endomyocardial and epimyocardial layers were inversely related to the extent of infarction. For given degrees of infarction, myocardial blood flow was significantly higher (greater than twofold) in the reperfused group. Myocardial samples with extensive infarction (51-75%) showed only mild (20-30%) reductions in blood flow when compared with nonischemic regions in the reperfused group. Thus, although early reperfusion may salvage ischemic myocardium, these studies showed that reperfusion causes a new relation between blood flow to the ischemic region and eventual histologic infarct size. When myocardial blood flow is used as an index of myocardial salvage after reperfusion, the basic relation obtained from permanent occlusion studies substantially overestimates the extent of myocardial salvage and underestimates the degree of remaining infarction.

Effects of atrial natriuretic peptide on transmural blood flow and reactive hyperemia in the presence of flow-limiting coronary stenosis in the awake dog: evidence for dilation of the intramural vasculature

The effects of atrial natriuretic peptide (ANP) on transmural myocardial blood flow distribution and the reactive hyperemic response in the presence and absence of flow-limiting coronary stenosis were examined in chronically instrumented conscious dogs. Ten-second coronary occlusion without subsequent flow restriction resulted in marked reactive hyperemic responses (Doppler flow probes), mean flow debt repayment was 481 +/- 55%. When the 10-second coronary occlusions were followed by a 20-second partial restriction that allowed normal preocclusion coronary inflow, the subsequent reactive hyperemia was significantly augmented, mean flow debt repayment was 938 +/- 91% (p less than 0.05). Pretreatment with ANP (3 micrograms/kg) did not alter the flow debt repayment after a 10-second occlusion without restriction (474 +/- 30%, NS) but attenuated the augmentation of reactive hyperemia resulting from the 20-second inflow restriction, flow debt repayment (613 +/- 66%, NS). Regional myocardial blood flow to the ischemic region was measured during restricted inflow after a 10-second coronary occlusion before and after ANP pretreatment. Before ANP, subendocardial flow decreased (0.54 +/- 0.04 ml/min/g) and subepicardial flow significantly increased (1.03 +/- 0.12 ml/min/g) when compared with the nonischemic zone (subendocardial, 1.03 +/- 0.09 ml/min/g; subepicardial, 0.87 +/- 0.09 ml/min/g, p less than 0.05), indicating maldistribution of the restricted inflow. The resultant subendocardial-to-subepicardial ratio in the ischemic region was significantly decreased when compared with the nonischemic region (0.56 +/- 0.03 vs. 1.18 +/- 0.04, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Trypsin digestion of junctional sarcoplasmic reticulum vesicles

A putative constituent of the junctional processes, connecting the terminal cisternae of sarcoplasmic reticulum and the transverse tubules of skeletal muscle fibers, is a greater than or equal to 350,000-dalton (Da) protein that displays ryanodine binding and Ca2+ channel properties. Ryanodine modulation of Ca2+ fluxes suggests that the ryanodine receptor and calcium channel are integral parts of one functional unit corresponding to the greater than or equal to 350,000-Da protein [Inui, M., Saito, E., & Fleischer, S. (1987) J. Biol. Chem. 262, 1740-1747; Campbell, K. P., Knudson, C. M., Imagawa, T., Leung, A. L., Sutko, J. L., Kahl, S. D., Raab, C. R., & Madson, L. (1987) J. Biol. Chem. 262, 6460-6463]. We subjected vesicular fragments of junctional-cisternal membrane to stepwise trypsin digestion. The greater than or equal to 350,000-Da protein is selectively cleaved in the early stage of digestion, with consequent disappearance of the corresponding band in electrophoretic gels. The Ca2+-ATPase is cleaved at a later stage, while calsequestrin is not digested under the same experimental conditions. While the Ca2+-ATPase yields two complementary fragments that are relatively resistant to further digestion, the greater than or equal to 350,000-Da protein yields fragments that are rapidly broken down to small peptides. Under conditions producing extensive digestion of the greater than or equal to 350,000-Da protein, the junctional processes are still visualized by electron microscopy, with no discernible alterations of their ultrastructure. The functional properties of the Ca2+ release channel are also maintained following trypsin digestion, including blockage by Mg2+ and ruthenium red and activation by Ca2+ and nucleotides.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial infarction and risk region relationships: evaluation by direct and noninvasive methods

Optimal quantitation of myocardial infarction requires resolution of the three-dimensional geometry of the ischemic region at a time that progression of tissue necrosis has been completed and can be sharply delineated from noninfarcted myocardium but before significant remodeling of the ventricular chamber. Although this can be achieved at two to three days after coronary occlusion by histologic techniques, a variety of technologies including two-dimensional echo, CTT, SPECT, PET, and NMR have demonstrated potential for providing noninvasive quantitative measurements of the extent of myocardial infarction. Additional studies are needed to clarify the utility of these technologies for resolving the highly variable transmural distribution of infarction that is present in the clinical setting. Assessment of the region at risk for infarction, the ischemic zone, requires quantitative measurements of the degree of ischemia as well as the size of the ischemic region. Although the above technologies may provide quantitative measurements of the dimensions of the ischemic zone, the utility for resolving the highly variable transmural distribution of regional myocardial blood flow using clinically applicable methodologies has not been convincingly established at present. It is possible that cine CT, new generation PET, and NMR technologies may eventually provide noninvasive quantitative measurements of regional myocardial blood flow.

Inhibitors of sterol synthesis. Reverse phase high performance liquid chromatography for the separation of cholesterol, 5 alpha-cholest-8(14)-en-3 beta-ol-15-one, and their fatty acid esters

A relatively simple and rapid method was required for the separation of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one, a potent inhibitor of sterol synthesis, from its major metabolites. Conditions have been determined which permit the resolution of the 15-ketosterol and cholesterol and fatty acid esters of the two sterols by reverse phase high performance chromatography. This methodology also permits the resolution of the major esters of the 15-ketosterol and of cholesterol.

Vasoactive effects of serotonin on proximal coronary arteries in awake dogs

This study evaluates the vasoactive effects and mechanisms of action of serotonin on epicardial arteries in awake dogs chronically instrumented with miniature piezoelectric dimension crystals on the proximal circumflex coronary artery. Serotonin (2-16 micrograms) infused as a bolus in the left atrium effected a dose-related biphasic response, which was characterized by an initial increase in vessel dimension with a peak response at 45-75 seconds, followed by a delayed and more sustained vasoconstriction, with a maximum response at 2-8 minutes. The magnitude of the initial vasodilation was generally greater than the delayed vasoconstriction. The initial vasodilation remained unchanged after selective S2 blockade with ketanserin (0.3 mg/kg) and was only minimally but insignificantly attenuated when flow was held constant but was reduced after S1 and S2 blockade with methysergide (0.25 mg/kg). Selective S2 blockade with ketanserin (0.3 mg/kg) attenuated the delayed vasoconstriction in most but not all dogs; the effect of ketanserin was, however, not significant when the entire group was considered. Selective endothelial denudation effectively eliminated the initial vasodilation response to serotonin and significantly augmented the delayed vasoconstriction when the dogs were studied 1-2 days after denudation. The data indicate that in the awake dog, serotonin effects a biphasic vasomotor response characterized by an initial vasodilation that is mediated primarily through a direct endothelium-dependent S1 mechanism followed by a delayed vasoconstriction that is probably mediated via a direct S2 effect on the vascular smooth muscle and is attenuated by the normal endothelium.

Effects of atrial natriuretic peptide on proximal epicardial coronary arteries and coronary blood flow in conscious dogs

The effects of atrial natriuretic peptide (ANP) on proximal epicardial coronary artery dimensions and coronary blood flow were examined in 7 awake dogs chronically instrumented with miniature coronary dimension crystals and Doppler flow probes on the circumflex coronary artery. ANP (10, 50, and 150 micrograms) was infused as a bolus via the left atrial catheter. Aortic pressure, left ventricular end-diastolic pressure, heart rate, and dP/dt did not change significantly with any dose of ANP. ANP caused transient (1-5 minutes) dose-related increases in coronary blood flow; maximum increases were 28.1 +/- 6.9%, 40.2 +/- 6.2%, and 73.9 +/- 12.5% with the 10-, 50-, and 150-micrograms doses, respectively. ANP also induced prolonged (average 70.2 +/- 28.6 minutes with 150-micrograms dose) dose-related increases in coronary diameter; maximum increases were 3.1 +/- 1.0%, 3.9 +/- 1.5%, and 5.7 +/- 1.3% with the 10-, 50-, and 150-micrograms doses, respectively. The increase in diameter was not attenuated when the transient increase in blood flow was prevented by partial occlusion with a pneumatic snare. Combined autonomic blockade with propranolol (1 mg/kg), phentolamine (1 mg/kg), and atropine (0.06 mg/kg) attenuated the relative increase in coronary flow but did not alter the increases in epicardial coronary diameter produced by ANP. These data demonstrate that bolus injection of ANP effects preferential, sustained, dose-dependent, flow-independent increases in epicardial coronary dimensions and relatively brief dose-dependent increases in coronary blood flow. The vasodilator effects of ANP on epicardial vessels are direct and are not mediated via the autonomic nervous system.(ABSTRACT TRUNCATED AT 250 WORDS)