Observation of diffractive J/psi production at the Fermilab Tevatron

We report the first observation of diffractive J/psi(--> mu+mu-) production in pp collisions at root square[s] = 1.8 TeV. Diffractive events are identified by their rapidity gap signature. In a sample of events with two muons of transverse momentum p(mu)T>2 GeV/c within the pseudorapidity region /eta/ < 1.0, the ratio of diffractive to total J/psi production rates is found to be R(J/psi) = [1.45 +/- 0.25]%. The ratio R(J/psi)(x) is presented as a function of x-Bjorken. By combining it with our previously measured corresponding ratio R(jj)(x) for diffractive dijet production, we extract a value of 0.59 +/- 0.15 for the gluon fraction of the diffractive structure function of the proton.

Search for quark-lepton compositeness and a heavy W' Boson using the enu channel in p p macro collisions at square root of [s] = 1.8 TeV

We present searches for quark-lepton compositeness and a heavy W' boson at high electron-neutrino transverse mass. We use approximately 110 pb(-1) of data collected in p p macro collisions at square root of [s] = 1.8 TeV by the CDF Collaboration during 1992-1995. The data are consistent with standard model expectations. Limits are set on the quark-lepton compositeness scale Lambda, the ratio of partial cross sections sigma(W'-->enu)/sigma(W-->enu), and the mass of a W' boson with standard model couplings. We exclude Lambda<2.81 TeV and a W' boson with mass below 754 GeV/c(2) at the 95% confidence level. Combining with our previously published limit obtained using the muon channel, we exclude a W' boson with mass below 786 GeV/c(2) at the 95% confidence level.

Charged-particle multiplicity pp collisions at square root of (s) = 1.8 TeV

We report on a measurement of the mean charged-particle multiplicity of jets in dijet events with dijet masses in the range 80-630 GeV/c(2), produced at the Tevatron in pp collisions with square root (s) = 1.8 TeV and recorded by the Collider Detector at Fermilab. The data are fit to perturbative-QCD calculations carried out in the framework of the modified leading log approximation and the hypothesis of local parton-hadron duality. The fit yields values for two parameters in that framework: the ratio of parton multiplicities in gluon and quark jets, r identical withN(g-jet)(partons)/N(q-jet)(partons) = 1.7+/-0.3, and the ratio of the number of charged hadrons to the number of partons in a jet, K(charged)(LPHD) identical with N(charged)(hadrons)/N(partons) = 0.57+/-0.11.

Double diffraction dissociation at the Fermilab Tevatron collider

We present results from a measurement of double diffraction dissociation in pp collisions at the Fermilab Tevatron collider. The production cross section for events with a central pseudorapidity gap of width Deltaeta(0)>3 (overlapping eta = 0) is found to be 4.43+/-0.02(stat)+/-1.18(syst) mb [ 3.42+/-0.01(stat)+/-1.09(syst) mb] at square root of (s) = 1800[630] GeV. Our results are compared with previous measurements and with predictions based on Regge theory and factorization.

Measurement of d sigma/dM and forward-backward charge asymmetry for high-mass Drell-Yan e(+)e(-) pairs from pp macro collisions at square root of s = 1.8 TeV

We report on a measurement of the mass dependence of the forward-backward charge asymmetry, A(FB), and production cross section d sigma/dM for e(+)e(-) pairs with mass M(ee)>40 GeV/c(2). The data sample consists of 108 pb(-1) of pp macro collisions at square root of s = 1.8 TeV taken by the Collider Detector at Fermilab during 1992-1995. The measured asymmetry and d sigma/dM are compared with the predictions of the standard model and a model with an extra Z' gauge boson.

Measurement of the top quark p(T) distribution

We have measured the p(T) distribution of top quarks that are pair produced in pp collisions at sqrt[s] = 1.8 TeV using a sample of tt decays in which we observe a single high- p(T) charged lepton, a neutrino, and four or more jets. We use a likelihood technique that corrects for the experimental bias introduced due to event reconstruction and detector resolution effects. The observed distribution is consistent with the standard model prediction. We use these data to place limits on the production of high- p(T) top quarks suggested in some models of anomalous top quark pair production.

Direction of gaze while walking a simple route: persons with normal vision and persons with retinitis pigmentosa

PURPOSE

The purpose of this study was to determine whether persons with advanced vision impairment, when walking an unfamiliar route, visually sample the environment in a different manner than do persons with normal vision.

METHODS

Direction of gaze was measured in six persons with retinitis pigmentosa (RP) and in three persons with normal vision as they walked an unfamiliar, obstacle-free route while viewing the environment in a head-mounted display.

RESULTS

Persons with RP fixated over a larger area in the environment and at different features than did persons with normal vision. Persons with normal vision directed their gaze primarily ahead or at the goal, whereas persons with RP directed their gaze at objects on the walls, downward, or at the layout (i.e., edge-lines or boundaries between walls). The results also showed a significant negative correlation between the horizontal visual field extent of the RP subjects and the proportion of downward-directed fixations.

CONCLUSIONS

Persons with advanced vision impairment as a result of RP visually sample the environment in a manner different from persons with normal vision.

Search for neutral supersymmetric Higgs bosons in pp collisions at sqrt[s] = 1.8TeV

We present the results of a search for neutral Higgs bosons produced in association with b quarks in pp-->bb(phi)-->bbb final states with 91+/-7 pb(-1) of pp collisions at sqrt[s] = 1.8 TeV recorded by the Collider Detector at Fermilab. We find no evidence of such a signal and the data are interpreted in the context of the neutral Higgs sector of the minimal supersymmetric extension of the standard model. With basic parameter choices for the supersymmetric scale and the stop-quark mixing, we derive 95% C.L. lower mass limits for neutral Higgs bosons for tan(beta) values in excess of 35.

Production of chi(c1) and chi(c2) in pp collisions at sqrt[S] = 1.8 TeV

We have measured the ratio of prompt production rates of the charmonium states chi(c1) and chi(c2) in 110 pb(-1) of pp collisions at sqrt[s] = 1.8 TeV. The photon from their decay into J/psi(gamma) is reconstructed through conversion into e+e- pairs. The energy resolution this technique provides makes the resolution of the two states possible. We find the ratio of production cross sections sigma(chi(c2))/sigma(chi(c1)) = 0.96+/-0.27(stat)+/-0.11(syst) for events with pT(J/psi) > 4.0 GeV/c, /eta(J/psi)/ < 0.6, and pT(gamma) > 1.0 GeV/c.

First measurement of the ratio B(t --> Wb)/B(t --> Wq) and associated limit on the Cabibbo-Kobayashi-Maskawa element /V(tb)/

We present the first measurement of the ratio of branching fractions R identical withB(t-->Wb)/B(t-->Wq) from p_p collisions at sqrt[s] = 1.8 TeV. The data set corresponds to 109 pb(-1) of data recorded by the Collider Detector at Fermilab during the 1992-95 Tevatron run. We measure R = 0.94(+0.31)(-0.24)(stat+syst) or R>0.61 (0.56) at 90% (95)% C.L., in agreement with the standard model predictions. This measurement yields a limit on the Cabibbo-Kobayashi-Maskawa quark mixing matrix element /V(tb)/ under the assumption of three generations and unitarity.

Measurement of J/psi and psi(2S) polarization in pp collisions at sqrt[s] = 1.8 TeV

We have measured the polarization of J/psi and psi(2S) mesons produced in pp collisions at sqrt[s] = 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5]<P(T)<20 GeV/c and |y|<0.6. For P(T) greater than or approximately equal 12 GeV/c we do not observe significant polarization in the prompt component.

Search for scalar top and scalar bottom quarks in pp collisions at square root s=1.8 TeV

We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb-1 of pp collisions at sqrt[s]=1.8 TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top (bottom) quark decays to a charm (bottom) quark and a neutralino. The numbers of events that pass our selections show no significant deviation from standard model expectations. We compare our results to the next-to-leading order scalar quark production cross sections to exclude regions in scalar quark-neutralino mass parameter space.

Search for a W' boson via the decay mode W'-->munumu in 1.8 TeV pp collisions

We report the results of a search for a W' boson produced in pp collisions at a center-of-mass energy of 1.8 TeV using a 107 pb-1 data sample recorded by the Collider Detector at Fermilab. We consider the decay channel W'-->&munumu and search for anomalous production of high transverse mass munumu lepton pairs. We observe no excess of events above background and set limits on the rate of W' boson production and decay relative to standard model W boson production and decay using a fit of the transverse mass distribution observed. If we assume standard model strength couplings of the W' boson to quark and lepton pairs, we exclude a W' boson with invariant mass less than 660 GeV/c2 at 95% confidence level.

Sequential programs of retinoic acid synthesis in the myocardial and epicardial layers of the developing avian heart

Endogenous patterns of retinoic acid (RA) signaling in avian cardiac morphogenesis were characterized by localized expression of a key RA-synthetic enzyme, RALDH2, which displayed a biphasic pattern during heart development. RALDH2 immunoreactivity was initially apparent posterior to Hensen's node of stage 5-6 embryos and subsequently in somites and unsegmented paraxial and lateral plate mesoderm overlapping atrial precursors in the cardiogenic plate of stage 9- embryos. Initial RALDH2 synthesis in the posterior myocardium coincided with activation of the AMHC1 gene, a RA-responsive marker of inflow heart segments. A wave of RALDH2 synthesis then swept the myocardium in a posterior-to-anterior direction, reaching the outflow tract by stage 13, then fading from the myocardial layer. The second phase of RALDH2 expression, initiated at stage 18 in the proepicardial organ, persisted in migratory epicardial cells that completely enveloped the heart by stage 24. Early restriction of RALDH2 expression to the posterior cardiogenic plate, overlapping RA-inducible gene activation, provides evidence for commitment of posterior avian heart segments by localized production of RA, whereas subsequent RALDH2 expression exclusively in the migratory epicardium suggests a role for the morphogen in ventricular expansion and morphogenesis of underlying myocardial tissues.

A retinoic acid-inducible transgenic marker of sino-atrial development in the mouse heart

To study the specification of inflow structures in the heart we generated transgenic animals harboring the human alkaline phosphatase (HAP) gene driven by the proximal 840 bp of a quail SMyHC3 promoter. In transgenic mice, the SMyHC3-HAP reporter was expressed in posterior heart precursors at 8.25 dpc, in sinus venosa and in the atrium at 8.5 and 9.0 dpc, and in the atria from 10.5 dpc onwards. SMyHC3-HAP transgene expression overlapped synthesis and endogenous response to retinoic acid (RA) in the heart, as determined by antibodies directed against a key RA synthetic enzyme and by staining of RAREhsplacZ transgenic animals. A single pulse of all-trans RA administered to pregnant mice at 7.5, but not after 8.5, dpc induced cardiac dismorphology, ranging from complete absence of outflow tract and ventricles to hearts with reduced ventricles expressing both SMyHC3-HAP and ventricular markers. Blockade of RA synthesis with disulfiram inhibited RA-induced transcription and produced hearts lacking the atrial chamber. This study defines a novel marker for atrial-restricted transcription in the developing mouse heart. It also suggests that atrial-specific gene expression is controlled by localized synthesis of RA, and that exclusion of RA from ventricular precursors is essential for correct specification of the ventricles.

Dynamic patterns of retinoic acid synthesis and response in the developing mammalian heart

Retinoic acid (RA) has been implicated in cardiac morphogenesis by its teratogenic effects on the heart, although its role in normal cardiogenesis remains unknown. To define the parameters of RA action in cardiac morphogenesis, we analyzed the patterns of ligand synthesis, response, and inactivation in the developing mouse heart. Activation of a lacZ transgene controlled by an RA response element (RARE) was compared to the localization of the retinaldehyde-oxidizing dehydrogenase RALDH2, the earliest RA synthetic enzyme in the mouse embryo, and to the expression of a gene encoding an RA-degrading enzyme (P450RA). We observed that RALDH2 localization and RA response were virtually superimposable throughout heart development. Initially, both RALDH2 and RARE-LacZ activity were restricted to the sinus venosa in unlooped hearts, but were high in the dorsal mesocardium, while P450RA expression was restricted to the endocardium. Later stages were characterized by a sequential, noncontiguous progression of RALDH2 accumulation and RA response, from the sinus venosa to atria, dorsal-medial conotruncus, aortic arches, and the epicardium. This dynamic pattern of RA response was a direct result of localized RALDH2, since hearts of cultured embryos were uniformly competent to respond to an exogenous RA challenge. These observations support a model in which the influence of endogenous RA on heart development depends upon localized presentation of the ligand, with only limited diffusion from the source of its synthesis.

Role of aldosterone in the sodium retention of patients with nephrotic syndrome

The role of aldosterone in the abnormal sodium retention in patients with nephrotic syndrome has been debated. In fact, studies using a converting enzyme inhibitor to lower plasma aldosterone have rejected such a role. We therefore studied 5 nephrotic patients and 6 control subjects by using the more specific aldosterone antagonist, spironolactone. After withdrawal of diuretics 5 days prior to the study, the nephrotic patients and control subjects were placed on a high-sodium diet (285 +/- 6 mEq/day) for 8 days. After 4 days, spironolactone 200 mg p.o., b.i.d., was given for the remaining 4 days. Plasma renin activity and plasma aldosterone levels were similar in both nephrotic patients and control subjects before the study, after sodium loading and after spironolactone had been given. After 4 days of high sodium intake control subjects were in sodium balance, but the nephrotic patients were in a positive sodium balance (approx. 80 mEq/day; p less than 0.01). On days 3 and 4 of spironolactone, the nephrotic patients exhibited an increase in urinary sodium excretion (205 +/- 20 vs. 312 +/- 13 mEq/day; p less than 0.005) but not the control subjects (279 +/- 16 vs. 286 +/- 13 mEq/day; NS). It is therefore concluded that aldosterone is a significant contributor to the sodium retention in patients with nephrotic syndrome.

MRI of the parapharyngeal space

Magnetic resonance imaging has replaced contrast-enhanced CT as the primary imaging modality for parapharyngeal space masses. It has several advantages over CT. MRI's superior contrast resolution enables the imager to better define normal anatomic structures and establish more precise tumor margins. Magnetic resonance's direct multiplanar imaging capability allows the diagnostician to offer his clinical colleagues a more accurate assessment of the total extent (in three dimensions) of disease and a better map of the spatial relationship of tumors to crucial vessels. This important information aids the clinician in making better informed decisions concerning the appropriate treatment plan (surgery versus radiation, surgical approach, radiation ports). Magnetic resonance's major inadequacy, compared with CT, is suboptimal detection of calcifications and subtle bony changes. Because of this, there are clinical situations when both MRI and CT are required, either to make a more definitive diagnosis or to include (exclude) certain pathology in (from) the differential diagnosis. Although there is considerable overlap in the signal intensity of various lesions, it probably is beyond realistic expectations to seek complete tissue specificity from any imaging tool. Hopefully, MRI spectroscopy will enable us, as imagers, in combination with our basic science colleagues, to take that giant step forward.

MRI of the paranasal sinuses and nasal cavity

In the evaluation of soft tissue masses of the paranasal sinuses and nasal cavity, MR has excelled, not only in sensitivity, but in specificity. Without question, MR has improved the diagnostic accuracy for distinguishing neoplasms from inflammatory diseases. This improved discrimination is primarily due to the combination of the superior soft tissue contrast of MRI and the widely disparate T2-relaxation values between the neoplasms and inflammatory processes indigenous to this anatomic area. MR's expanding role as the primary imaging modality for clinical problems in the sinonasal region will accompany the decrease in exam time and increase in spatial resolution. In the past few years there has been a rapid expansion in MRI's utility for a variety of clinical situations in the sinonasal region. This trend should accelerate, especially with the decrease in exam time and increase in spatial resolution that will accompany other expeditious technologic advancements.

Sinonasal tumors and inflammatory tissues: differentiation with MR imaging

The magnetic resonance (MR) and computed tomographic (CT) images of 53 patients with sinonasal tumors were analyzed and compared for accuracy in tumor mapping. the findings were confirmed by means of either surgery or biopsy. The MR images of 60 patients with inflammatory disease were also studied, and the findings were confirmed at surgery. Forty-seven additional MR images were also examined of patients with tumors showing histologic characteristics similar to those found in the sinonasal tumor group but occurring elsewhere in the head and neck, excluding the orbit. This study concludes that nearly 95% of sinonasal tumors have an intermediate T2 signal, while only 5% have bright T2 signals. This small latter group is composed almost exclusively of some minor salivary gland tumors and some neuromas. The inflammatory tissues all had bright T2 signals. The distinction between sinonasal tumors and inflammatory tissues was best accomplished with T2-weighted studies, and MR imaging was more accurate than CT.

Tumors of the parapharyngeal space and upper neck: MR imaging characteristics

Magnetic resonance (MR) imaging characteristics of 40 tumors involving the parapharyngeal space and the upper part of the neck were reviewed. These lesions could be classified as being either hypervascular (glomus tumors or metastatic kidney, thyroid, or venous hemangiomas) or hypovascular (salivary gland tumors, neurogenic tumors, lymphomas, sarcomas). Detailed analysis of the contour of the neoplasm combined with clinical findings allowed further refinement of the differential diagnosis in each category. Most lesions had an intermediate signal intensity on T1-weighted images and a fairly high signal intensity on T2-weighted images. Hypervascular tumors had a number of "channel voids" caused by high-flow vessels on T1- and T2-weighted images, and on T2-weighted images there were areas of high signal intensity, presumably due to sites of slow flow within the image plane. The hypovascular lesions were quite homogeneous, and it was therefore more difficult to differentiate among the neoplasms in this group.

Orbital metastasis: role of magnetic resonance imaging and computed tomography

Imaging of ocular and oral metastasis with CT and MRI is discussed. The relative advantages and disadvantages of the two techniques are presented. MRI seems to be particularly useful in discriminating intraocular tumor from retinal detachment. Both techniques depict orbital lesions well.

Minimal asymmetry of the brain: a normal variant

Normal cerebral asymmetry, well-known to neuroradiologists, is not widely recognized by radiologists in general. In our review of CT brain scans, 31 of 300 patients with a negative neurologic examination and no history of birth injury, head trauma, or seizure had recognizable asymmetry of the frontal horns of the lateral ventricles. The right frontal horn and the right cerebral hemispheres were larger than the left twice as often as left were larger than right. The right frontal lobe was wider than the left in 44% of patients and extended as far anteriorly or more anteriorly than the left in 22% of patients. The right central hemispheric mass tended to be wider than the left, resulting in slight displacement of the pineal gland to the left, in approximately 45% of cases. The posterior end of the left Sylvian fissure projected farther posteriorly in 10% of the patients. Occipital petalia and a more posterior position of the calcified glomus of the choroid plexus of the lateral ventricle were both common on the left side of 56%. Earlier studies of the brain by other methods have also shown asymmetry. An awareness of these anatomic asymmetries in normal individuals should preclude the erroneous diagnosis of an atropic or mass lesion.

Factors determining renal response to water immersion in non-excretor cirrhotic patients

Non-excretor cirrhotic patients, defined by their inability to normally excrete a standard water load, display variable responses to head-out water immersion. The hemodynamic, hormonal, and renal functional status of fifteen such patients were analyzed relative to water excretion during head-out water immersion. Group 1 patients (N = 7) all excreted less than 40% of the water load during immersion, whereas excretion was greater than 40% in all eight patients in Group 2. Group 1 patients, when compared with Group 2, had more ascites, more diuretic resistance, lower serum sodium concentration (125 +/- 2 vs. 130 +/- 1 mEq/liter, P less than 0.05), and more impaired baseline water excretion (12.9 +/- 1.2 vs. 35.9 +/- 5.9% of water load in 5 hr, P less than 0.005). Systemic hemodynamic responses to water immersion were similar in both groups. Glomerular filtration rate and renal plasma flow were significantly more impaired in Group 1 patients (inulin clearance 28 +/- 6 vs. 62 +/- 9 ml/min/1.73 m2, P less than 0.05; para-aminohippurate clearance 212 +/- 35 vs. 357 +/- 37 ml/min, P less than 0.05). Concentrations of plasma vasopressin (1.7 +/- 0.5 vs. 0.8 +/- 0.1 pg/ml, P less than 0.05), renin (8.6 +/- 1.7 vs. 3.8 +/- 0.9 ng/ml/hr, P less than 0.05), aldosterone (82 +/- 14 vs. 39 +/- 10 ng/dl, P less than 0.05) and norepinephrine (1155 +/- 183 vs. 603 +/- 126 pg/ml, P less than 0.05) were all significantly higher in Group 1 than Group 2 patients during water immersion.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of glomerular filtration rate in the impaired sodium and water excretion of patients with the nephrotic syndrome

Hemodynamic and hormonal factors were monitored in nine patients with nephrotic syndrome who were evaluated relative to their capacity to excrete a 20-mL/kg water load (normal greater than 80%). In five "nonexcretor" patients (37% of water load excreted in five hours), as compared to four normal excretors (105% of water load excreted in five hours; P less than .01 v nonexcretors), neither BP (131/88 v 119/79 mm Hg), pulse (74 v 77 beats/min), cardiac index (3.7 v 3.1 L/min/m2), pulmonary wedge pressure (9.3 v 7.3 mm Hg), systemic vascular resistance (1537 v 1254 dynes-sec-cm-5), nor plasma volume (41.3 v 40.1 mL/kg) were different. Similarly, plasma renin activity (2.6 v 3.7 ng/mL/h), plasma aldosterone (12 v 10.9 ng/dL), and plasma norepinephrine (403 v 312 pg/mL) were not different between nonexcretor v excretor patients with nephrotic syndrome. Plasma vasopressin concentrations were also similar both before (3.1 +/- 0.8 v 2.4 +/- 1.2 pg/mL) and during the water load (0.9 +/- 0.3 v 1.0 +/- 0.4 pg/mL). Inulin clearances, however, were lower in the nonexcretor v the excretor nephrotic patients (37 v 78 mL/min/1.73 m2; P less than .02) and correlated with water excretion (r = .68; P less than .05). Head-out water immersion increased sodium (40 to 110 microEq/min; P less than .01) and water excretion (37% to 82%; P less than .025) in the nonexcretors; the improvement correlated with the increase in inulin clearance during immersion (r = .70; P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

The role of intensive dialysis in acute renal failure

The efficacy of vigorous dialysis in the management of acute renal failure remains controversial. In order to examine the beneficial role of vigorous dialysis, a prospective study was carried out in 34 patients paired by acute renal failure etiology and treated with sufficient dialysis to maintain predialysis blood urea nitrogen and serum creatinine below either 60 and 5 mg/dl (intensive) or 100 and 9 mg/dl, respectively (non-intensive). Serum creatinine was at least 8 mg/dl in all patients prior to random assignment to intensive or non-intensive dialysis. Mean predialysis blood urea nitrogen and serum creatinine, respectively, were 60 +/- 23 and 5.3 +/- 1.5 mg/dl in the intensively dialyzed group and 101 +/- 18 and 9.1 +/- 1.4 mg/dl in the non-intensively dialyzed group (both p less than .001). Predialysis serum bicarbonate and blood pH were lower and serum phosphate higher in the non-intensively dialyzed patients. Daily weight changes, increases in blood urea nitrogen, protein and calorie intakes were similar. While hemorrhagic episodes tended to be more frequent in non-intensively dialyzed patients, overall complication rates were not different between the two groups. Mortality rates, which were 58.8% in the intensive and 47.1% in the non-intensive groups, also were not different. On the other hand, urine output prior to dialysis did influence survival. It is concluded that, within the limits of the study, there is no advantage to intensive dialysis in the management of acute renal failure.

Sodium excretion in advanced cirrhosis: effect of expansion of central blood volume and suppression of plasma aldosterone

Sodium excretion in 13 patients with decompensated cirrhosis was measured under baseline conditions of water loading (n = 13) and during conditions designed to improve effective blood volume including: head-out water immersion alone (n = 13); norepinephrine infusion alone (n = 6), and combined norepinephrine and head-out water immersion (n = 6). All 13 patients were in positive sodium balance under baseline conditions, with a mean plasma aldosterone concentration of 78.7 +/- 15.6 ng per dl. In only four patients was plasma aldosterone less than 50 ng per dl. During head-out water immersion alone, 5 patients achieved negative sodium balance and, in all 5, plasma aldosterone was less than 50 ng per dl (mean = 23.0 +/- 5.3 ng per dl). However, the mean plasma aldosterone during head-out water immersion in the eight patients who remained in positive sodium balance during this maneuver was 64.0 +/- 11.9 ng per dl (p less than 0.01). During norepinephrine alone, positive sodium balance was maintained in all patients, and plasma aldosterone was not significantly different from baseline. Combining norepinephrine and head-out water immersion resulted in the largest and most consistent negative sodium balance. The mean plasma aldosterone concentration was decreased significantly (78.7 +/- 15.6 to 32.6 +/- 9.9 ng per dl (p less than 0.05). Regardless of the maneuver performed, no patient in whom aldosterone exceeded 50 ng per dl achieved negative sodium balance. Furthermore, only in those studies utilizing head-out water immersion, with or without norepinephrine, was negative sodium balance seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Interrelationship between cardiac output and vascular resistance as determinants of effective arterial blood volume in cirrhotic patients

The effect of head-out water immersion (HWI) in decompensated cirrhotic patients to correct sodium and water excretion has been found to be incomplete and variable. The explanation may be that the efficacy of HWI in correcting a decreased effective arterial blood volume (EABV) in decompensated cirrhotic patients is limited by an accompanying decrease in systemic vascular resistance (SVR) and thus a relative increase in arterial vascular holding capacity. The present studies were undertaken to examine this possibility by maintaining SVR (dynes X sec X cm-5) nearly constant during HWI with an exogenous infusion of norepinephrine (HWI + NE). In six decompensated cirrhotic patients, neither HWI nor NE infusion alone significantly increased sodium excretion (UNaV, 13 vs. 19 and 13 microEq/min, respectively), but each maneuver increased the excretion of a 20 ml/kg water load (28 to 60 and 61%, respectively, both P less than 0.05). The combination of HWI + NE, however, significantly increased UNaV to 70 microEq/min (P less than 0.05) and percentage of water excretion to 95 (P less than 0.001), values significantly greater than those achieved with either maneuver alone. These differences were not explained by any changes in inulin clearance. With HWI alone, cardiac index (CI) increased (4.2 to 5.3 liter/min/m2, P less than 0.01), but SVR decreased (872 to 613 dynes X sec X cm-5, P less than 0.001) and mean arterial pressure (MAP) remained constant (83 vs. 78 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated plasma norepinephrine concentrations in decompensated cirrhosis. Association with increased secretion rates, normal clearance rates, and suppressibility by central blood volume expansion

Plasma norepinephrine concentrations are elevated in patients with decompensated cirrhosis, and correlate inversely with urinary sodium and water excretion. Increased plasma norepinephrine concentrations may result from a decreased metabolic clearance rate or an increased secretion rate, possibly in response to a decreased "effective arterial blood volume." If the latter hypothesis is correct, plasma norepinephrine might be expected to be suppressed when central blood volume is expanded by head-out water immersion. In the present study, plasma norepinephrine secretion and clearance rates were determined by infusion of tritiated norepinephrine. Norepinephrine secretion rates were elevated in eight cirrhotic patients as compared to control subjects (1.50 +/- 0.25 vs. 0.26 +/- 0.08 micrograms/m2 per min, P less than 0.001), whereas clearance rates were similar (3.13 +/- 0.48 vs. 2.60 +/- 0.28 liters/min, NS). Baseline plasma norepinephrine concentrations were markedly elevated in the cirrhotic patients (830 +/- 136 vs. 185 +/- 12 pg/ml, P less than 0.001). Head-out water immersion significantly suppressed plasma concentrations of both norepinephrine (704 +/- 72 to 475 +/- 70 pg/ml, P less than 0.005) and epinephrine (121 +/- 33 to 57 +/- 10 pg/ml, P less than 0.05) in all seven patients studied. We conclude that the high circulating catecholamine concentrations in cirrhosis are secondary to increased secretion, rather than to decreased metabolic clearance, and are suppressible by central blood volume expansion.

Sodium chloride pica secondary to iron-deficiency anemia

A young woman was referred for nephrologic evaluation of hypertension and a curious desire for table salt. Suspicion of iron-deficiency anemia arose only after it was determined that sodium balance was achievable during supervised sodium restriction. This salt craving abated within 2 weeks of initiation of iron replacement therapy. Although pica is a common manifestation of iron deficiency, this appears to be the first reported case of salt pica secondary to iron deficiency.

Intranasal deamino-8-D-arginine vasopressin shortens the bleeding time in uremia

Clinical bleeding in uremia is a frequent problem and seems to correlate with a prolonged bleeding time. The vasopressin analog deamino-8-D-arginine vasopressin has been shown to shorten the bleeding time and to decrease clinical bleeding when administered intravenously to uremic patients. In the present study we administered the readily available intranasal deamino-8-D-arginine vasopressin to 2 uremic patients and demonstrated a decreased bleeding time and improvement in clinical bleeding.