Abdominal Inflammatory Myofibroblastic Tumor: Minimal Inflammatory Infiltrate and Diffuse Immunoreactivity for Caldesmon are Potential Diagnostic Pitfalls

Introduction/Objective

Inflammatory myofibroblastic tumor (IMT) is an uncommon spindle cell lesion that can involve various organs and occurs in multiple body sites. While older terminology (i.e. inflammatory pseudotumor) suggested otherwise, recent molecular studies point toward a neoplastic pathogenesis for IMTs. Herein, we report a case of an abdominal IMT and discuss the morphologic and immunohistochemical pitfalls pertaining to this entity.

Methods

A 75-year-old woman presented with complaints of generalized abdominal pain and distention. An abdominal CT scan showed multiple peritoneal masses, the largest of which measured 23 cm. Biopsy revealed compact fascicles of bland spindle cells exhibiting diffuse actin and caldesmon immunoreactivity, consistent with a spindle cell tumor with smooth muscle differentiation. Mitotic activity was low-to-unapparent. Surgical excision was performed. The cut surface of the tumor was tan-white with hemorrhagic foci. Histopathologic examination of the tumor showed elongated spindle cells set in a loose myxoid stroma rich in blood vessels and a mixed inflammatory infiltrate. Deeper sections of the tumor were more cellular, showing a similar morphology to that seen in the original biopsy, which was virtually devoid of inflammatory cells. Immunohistochemistry showed diffuse staining for desmin, caldesmon, smooth muscle actin, and ALK. FISH analysis showed ALK gene rearrangement in 52% of tumor cells, confirming the diagnosis of IMT.

Results

Studies in the literature show that IMTs express smooth muscle markers such as SMA (90%) and desmin (50%). However, immunoreactivity for caldesmon is rarely reported. ALK immunoreactivity is seen in about 35–60% of cases, and when gene rearrangement involving ALK is detected the diagnosis can be confirmed.

Conclusion

Historically, several terms have been used to describe IMTs, including inflammatory pseudotumor and inflammatory pseudosarcomatous fibromyxoid tumor. While the nomenclature consistently implies an inflammatory infiltrate, this tumor could have various morphological patterns with some areas showing very little to absent inflammation, as demonstrated in our case. Hence, making an accurate diagnosis could be challenging on a limited biopsy. Therefore, ALK testing should be included as part of the diagnostic workup of spindle cell neoplasms with smooth muscle differentiation.

Stellar dynamics. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova

Hypervelocity stars (HVSs) travel with velocities so high that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US 708. Traveling with a velocity of ~1200 kilometers per second, it is the fastest unbound star in our Galaxy. In reconstructing its trajectory, the Galactic center becomes very unlikely as an origin, which is hardly consistent with the most favored ejection mechanism for the other HVSs. Furthermore, we detected that US 708 is a fast rotator. According to our binary evolution model, it was spun-up by tidal interaction in a close binary and is likely to be the ejected donor remnant of a thermonuclear supernova.

An assessment of the carcinogenic potential of ezetimibe using nonclinical data in a weight-of-evidence approach

Ezetimibe blocks intestinal absorption of sterols via interaction with the Neimann-Pick C1-Like 1 (NPC1L1) transporter and is approved for use in the treatment of primary hyperlipidemia (heterozygous familial and non-familial), homozygous familial hypercholesterolemia, and homozygous sitosterolemia. A recently completed randomized clinical trial [simvastatin and ezetimibe in aortic stenosis (SEAS)] testing the effectiveness of Vytorin (a combination of simvastatin and ezetimibe) in patients with aortic stenosis reported an unexpected safety finding: an increase in overall cancer incidence and cancer-associated mortality (all types) in the treated groups relative to the placebo control. A subsequent meta-analysis utilizing a much larger database from two ongoing clinical trials indicated that the observed findings in the SEAS trial were likely due to chance and not a true drug-induced effect. Nonetheless, it has been suggested by various commentators on the SEAS trial that ezetimibe may be carcinogenic. The extensive nonclinical database for ezetimibe was used to test the hypothesis that ezetimibe may be a direct or indirect carcinogen. Using two different in silico approaches, ezetimibe showed no structural alerts for genetic toxicity or carcinogenicity. Ezetimibe was not genotoxic in two reverse mutation assays, one in vitro clastogenicity assay, and two mouse micronucleus assays. No evidence of proliferative lesions was observed in three species in studies of 1-12 months in duration. Ezetimibe was not carcinogenic in standard 2-year bioassays in mice and rats. Additionally, in these 2-year bioassays, no drug-related non-neoplastic lesions were noted. The absence of drug-induced non-neoplastic or proliferative lesions in these studies indicates that ezetimibe treatment was not associated with findings characteristic of carcinogens (i.e., DNA reactivity or cell proliferation) Administration of pharmacologic doses of ezetimibe to mice did not alter hepatic expression patterns of genes associated with apoptosis, cell proliferation, or epithelial-mesenchymal transition. No evidence of drug-induced tumors was observed in mice in which the molecular target of ezetimibe (NPC 1L1) was knocked out over the life span of the animal. In conclusion, the nonclinical data do not support the proposed hypothesis based on the single observation from the SEAS trial and, rather, support the conclusion that ezetimibe does not represent a carcinogenic hazard to humans using this drug in a therapeutic setting.

APH-2/nicastrin functions in LIN-12/Notch signaling in the Caenorhabditis elegans somatic gonad

Nicastrin is a recently identified member of high-molecular weight complexes containing presenilin. The Caenorhabditis elegans homolog of nicastrin, aph-2, was shown to be required for GLP-1/Notch signaling in the early embryo. In addition to the maternal-effect embryonic lethal phenotype, aph-2 mutant animals also display an egg-laying defect. We show that this latter defect is related to the SEL-12/presenilin egg-laying defect. We also show that aph-2 and sel-12 genetically interact and cooperate to regulate LIN-12/Notch signaling in the development of the somatic gonad. In addition, aph-2 and lin-12/Notch genetically interact. We illustrate a new role for aph-2 in facilitating lin-12 signaling in the somatic gonad, thus providing evidence that APH-2 is involved in both GLP-1/Notch- and LIN-12/Notch-mediated signaling events. Finally, we demonstrate that nicastrin can partially substitute for aph-2, suggesting a conservation of function between these proteins.

PS1 N- and C-terminal fragments form a complex that functions in APP processing and Notch signaling

Presenilin proteins play critical roles in the proteolytic processing of both Notch and amyloid precursor protein (APP). Presenilin itself undergoes endoproteolytic processing to generate an N-terminal and C-terminal fragment. As demonstrated previously, overexpression of presenilin 1 (PS1) holoprotein does not change the levels of the N-terminal and C-terminal fragments (NTF and CTF). When we coexpress the PS1 NTF and CTF, marked increases in the cellular levels of these fragments are seen. By coexpressing the PS1 NTF and CTF, we demonstrate conclusively that a noncovalent complex of the NTF and CTF is the active species of presenilin. However, although the PS1 NTF/CTF complex is necessary for gamma-secretase activity, it is not sufficient. Independent overexpression of the PS1 NTF and CTF was also used to show that the Asp-257 and Asp-385 mutations in PS1 decrease Abeta production by a direct effect on gamma-secretase activity and not by the inhibition of PS1 endoproteolysis.

Prevalence and predictive value of intermittent viremia with combination hiv therapy

CONTEXT

In HIV-infected patients having virologic suppression (plasma HIV RNA <50 copies/mL) with antiretroviral therapy, intermittent episodes of low-level viremia have been correlated with slower decay rates of latently infected cells and increased levels of viral evolution, but the clinical significance of these episodes is unknown.

OBJECTIVE

To determine if HIV-infected patients with intermittent viremia have a higher risk of virologic failure (confirmed HIV RNA >200 copies/mL).

DESIGN AND SETTING

Retrospective analysis of subjects in well-characterized cohorts, the AIDS Clinical Trials Group (ACTG) 343 trial of induction-maintenance therapy (August 1997 to November 1998) and the Merck 035 trial (ongoing since March 1995).

PATIENTS

Two hundred forty-one ACTG 343 patients, of whom 101 received triple-drug therapy throughout the study, and a small group of 13 patients from Merck 035 having virologic suppression after 6 months of indinavir-zidovudine-lamivudine.

MAIN OUTCOME MEASURES

Association of intermittent viremia (plasma HIV RNA >50 copies/mL with a subsequent measure <50 copies/mL) with virologic failure (2 consecutive plasma HIV RNA measures >200 copies/mL) in both study groups; evidence of drug resistance in 7 patients from the small (n = 13) study group with long-term follow-up.

RESULTS

Intermittent viremia occurred in 96 (40%) of the 241 ACTG 343 patients of whom 32 (13%) had 2 consecutive HIV RNA values >50 copies/mL during the median 84 weeks of observation (median duration of observation after first intermittent viremia episode was 46 weeks). Of the 101 individuals receiving triple-drug therapy throughout, 29% had intermittent viremia; the proportion of episodes occurring during the maintenance period was 64% for the entire cohort and 68% for the group not receiving triple-drug therapy throughout vs 55% for those who did (P =.25). Intermittent viremia did not predict virologic failure: 10 (10.4%) of 96 patients with and 20 (13.8%) of 145 patients without intermittent viremia had virologic failure (relative risk, 0.76; 95% confidence interval [CI], 0.29-1.72). In a Cox proportional hazards model, the risk for virologic failure was not significantly greater in the ACTG 343 patients with intermittent viremia (hazard ratio, 1.28; 95% CI, 0.59-2.79). Median viral load in 10 ACTG 343 patients assessed between 24 and 60 weeks of therapy using an ultrasensitive 2.5-copies/mL detection level assay was 23 copies/mL in those with intermittent viremia vs <2.5 copies/mL in those without (P =.15). Intermittent viremia occurred in 6 of 13 patients from the small study group assessed after 76 to 260 weeks of therapy (using the 2.5-copies/mL detection level assay) and was associated with a higher steady state of viral replication (P =.03), but not virologic failure over 4.5 years of observation. Viral DNA sequences from 7 patients did not show evolution of drug resistance.

CONCLUSIONS

Intermittent viremia occurred frequently and was associated with higher levels of replication (Merck 035), but was not associated with virologic failure in patients receiving initial combination therapy of indinavir-zidovudine-lamivudine (ACTG 343 and Merck 035). In this population, treatment changes may not be necessary to maintain long-term virologic suppression with low-level or intermittent viremia.

spr-2, a suppressor of the egg-laying defect caused by loss of sel-12 presenilin in Caenorhabditis elegans, is a member of the SET protein subfamily

Presenilin plays critical roles in the genesis of Alzheimer's disease and in LIN-12/Notch signaling during development. Here, we describe a screen for genes that influence presenilin level or activity in Caenorhabditis elegans. We identified four spr (suppressor of presenilin) genes by reverting the egg-laying defective phenotype caused by a null allele of the sel-12 presenilin gene. We analyzed the spr-2 gene in some detail. We show that loss of spr-2 activity suppresses the egg-laying defective phenotype of different sel-12 alleles and requires activity of the hop-1 presenilin gene, suggesting that suppression is accomplished by elevating presenilin activity rather than by bypassing the need for presenilin activity. We also show that SPR-2 is a nuclear protein and is a member of a protein subfamily that includes human SET, which has been identified in numerous different biochemical assays and at translocation breakpoints associated with a subtype of acute myeloid leukemia.

Mutation of the conserved N-terminal cysteine (Cys92) of human presenilin 1 causes increased A beta42 secretion in mammalian cells but impaired Notch/lin-12 signalling in C. elegans

The presenilin proteins are involved in the proteolytic processing of transmembrane proteins such as Notch/lin-12 and the beta-amyloid precursor protein (betaAPP). Mutation of a conserved cysteine (Cys60Ser) in the C. elegans presenilin sel-12 has a loss-of-function effect on Notch/lin-12 processing similar to that of null mutations in sel-12. In contrast, in mammalian cells, most missense mutations increase gamma-secretase cleavage of betaAPP. We report here that mutation of this conserved cysteine (Cys92Ser) in human presenilin 1 confers a loss-of-function effect in C. elegans, but causes increased A beta42 secretion in mammalian cells. These data suggest that the role of presenilins in Notch/lin-12 signalling and betaAPP processing are either separately regulated activities or independent activities of the presenilins.

Nicastrin modulates presenilin-mediated notch/glp-1 signal transduction and betaAPP processing

Nicastrin, a transmembrane glycoprotein, forms high molecular weight complexes with presenilin 1 and presenilin 2. Suppression of nicastrin expression in Caenorhabditis elegans embryos induces a subset of notch/glp-1 phenotypes similar to those induced by simultaneous null mutations in both presenilin homologues of C. elegans (sel-12 and hop-1). Nicastrin also binds carboxy-terminal derivatives of beta-amyloid precursor protein (betaAPP), and modulates the production of the amyloid beta-peptide (A beta) from these derivatives. Missense mutations in a conserved hydrophilic domain of nicastrin increase A beta42 and A beta40 peptide secretion. Deletions in this domain inhibit A beta production. Nicastrin and presenilins are therefore likely to be functional components of a multimeric complex necessary for the intramembranous proteolysis of proteins such as Notch/GLP-1 and betaAPP.

Effects of SEL-12 presenilin on LIN-12 localization and function in Caenorhabditis elegans

Presenilins have been implicated in the development of Alzheimer's disease and in facilitating LIN-12/Notch activity. Here, we use genetic methods to explore the relationship between C. elegans LIN-12 and SEL-12 presenilin. Reducing sel-12 activity can suppress the effects of elevated lin-12 activity when LIN-12 is activated by missense mutations but not when LIN-12 is activated by removal of the extracellular and transmembrane domains. These results suggest that SEL-12 does not function downstream of activated LIN-12. An active SEL-12::GFP hybrid protein accumulates in the perinuclear region of the vulval precursor cells (VPCs) of living hermaphrodites, consistent with a localization in endoplasmic reticulum/Golgi membranes; when sel-12 activity is reduced, less LIN-12 protein accumulates in the plasma membranes of the VPCs. Together with the genetic interactions between lin-12 and sel-12, these observations suggest a role for SEL-12 in LIN-12 processing or trafficking. However, SEL-12 does not appear to be a general factor that influences membrane protein activity, since reducing sel-12 activity does not suppress or enhance hypomorphic mutations in other genes encoding membrane proteins. We discuss potential parallels for the role of SEL-12/presenilin in facilitating LIN-12/Notch activity and in amyloid precursor protein (APP) processing.

LIN-12 protein expression and localization during vulval development in C. elegans

We have used a LIN-12::GFP fusion protein to examine LIN-12 accumulation during cell fate decisions important for vulval development. During the naturally variable anchor cell (AC)/ventral uterine precursor cell (VU) decision of the somatic gonad, a transcription-based feedback mechanism biases two equivalent cells so that one becomes the AC while the other becomes a VU. LIN-12::GFP accumulation reflects lin-12 transcription: LIN-12::GFP is initially present in both cells, but disappears from the presumptive AC and becomes restricted to the presumptive VU. During vulval precursor cell (VPC) fate determination, six equipotential cells uniformly transcribe lin-12 and have invariant fates that are specified by multiple cell-cell interactions. The pattern of LIN-12::GFP accumulation in VPCs and in the VPC lineages is dynamic and does not always reflect lin-12 transcription. In particular, LIN-12::GFP is expressed initially in all six VPCs, but appears to be reduced specifically in P6.p as a consequence of the activation of the Ras pathway by an EGF-like inductive signal from the AC. We propose that downregulation of LIN-12 stability or translation in response to inductive signalling helps impose a bias on lateral signalling and contributes to the invariant pattern of VPC fates.

Assessment of normal and mutant human presenilin function in Caenorhabditis elegans

We provide evidence that normal human presenilins can substitute for Caenorhabditis elegans SEL-12 protein in functional assays in vivo. In addition, six familial Alzheimer disease-linked mutant human presenilins were tested and found to have reduced ability to rescue the sel-12 mutant phenotype, suggesting that they have lower than normal presenilin activity. A human presenilin 1 deletion variant that fails to be proteolytically processed and a mutant SEL-12 protein that lacks the C terminus display considerable activity in this assay, suggesting that neither presenilin proteolysis nor the C terminus is absolutely required for normal presenilin function. We also show that sel-12 is expressed in most neural and nonneural cell types in all developmental stages. The reduced activity of mutant presenilins and as yet unknown gain-of-function properties may be a contributing factor in the development of Alzheimer disease.

PAR-2 is asymmetrically distributed and promotes association of P granules and PAR-1 with the cortex in C. elegans embryos

The par genes participate in the process of establishing cellular asymmetries during the first cell cycle of Caenorhabditis elegans development. The par-2 gene is required for the unequal first cleavage and for asymmetries in cell cycle length and spindle orientation in the two resulting daughter cells. We have found that the PAR-2 protein is present in adult gonads and early embryos. In gonads, the protein is uniformly distributed at the cell cortex, and this subcellular localization depends on microfilaments. In the one-cell embryo, PAR-2 is localized to the posterior cortex and is partitioned into the posterior daughter, P1, at the first cleavage. PAR-2 exhibits a similar asymmetric cortical localization in P1, P2, and P3, the asymmetrically dividing blastomeres of germ line lineage. This distribution in embryos is very similar to that of PAR-1 protein. By analyzing the distribution of the PAR-2 protein in various par mutant backgrounds we found that proper asymmetric distribution of PAR-2 depends upon par-3 activity but not upon par-1 or par-4. par-2 activity is required for proper cortical localization of PAR-1 and this effect requires wild-type par-3 gene activity. We also find that, although par-2 activity is not required for posterior localization of P granules at the one-cell stage, it is required for proper cortical association of P granules in P1.

Peripheral blood mononuclear cell dihydropyrimidine dehydrogenase activity in volunteers with and without diabetes mellitus

It has been reported that cancer patients with diabetes mellitus receiving a continuous infusion of 5-fluorouracil (5-FU) have more toxicity and higher plasma 5-FU levels that patients without diabetes mellitus. Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme in the catabolism of 5-FU. DPD activity in peripheral blood mononuclear cells has been reported to correlate inversely with 5-FU plasma levels in patients. We therefore undertook a study to compare the activity of DPD in peripheral blood mononuclear cells of human subjects with and without diabetes mellitus. The study groups comprised 43 volunteers with and 39 without diabetes mellitus, and peripheral blood mononuclear cell DPD activity was assayed on samples obtained between 8 a.m. and 11 a.m. DPD activity was not decreased in diabetic subjects. There was no relationship between DPD activity and gender body mass index, or race. There was a modest correlation between DPD activity and age (r=0.19, P =0.08). We conclude that increases in 5-FU-related toxicities in diabetics must be related to factors other than peripheral blood mononuclear cell DPD activity.

Facilitation of lin-12-mediated signalling by sel-12, a Caenorhabditis elegans S182 Alzheimer's disease gene

The lin-12 and glp-1 genes of Caenorhabditis elegans are members of the lin-12/Notch family of receptors for intercellular signals that specify cell fate. By screening for suppressors of a lin-12 gain-of-function mutation, we identified a new gene, sel-12, which appears to function in receiving cells to facilitate signalling mediated by lin-12 and glp-1. The sel-12 gene encodes a protein with multiple transmembrane domains, and is similar to S182, which has been implicated in early-onset familial Alzheimer's disease. The high degree of sequence conservation suggests that the function of the SEL-12 and S182 proteins may also be conserved.

Reduced alpha-2-antiplasmin levels in the nephrotic syndrome

Venous and arterial thromboembolism frequently complicate the nephrotic syndrome. Increased platelet aggregation, high levels of fibrinogen and other procoagulants, and depressed levels of antithrombin III and plasminogen are commonly cited as reasons. Less attention has been paid to changes in the hemostatic system which might protect against thrombosis. We found a high frequency of reduced alpha 2-antiplasmin levels in 40 patients with nephrotic syndrome, correlating with serum albumin and with antithrombin III levels. Since alpha 2-antiplasmin is a major determinant of the sensitivity of fibrin thrombi to lysis, and since reduced levels would be expected to promote fibrinolysis, we conclude that in many patients with nephrotic syndrome depressed antiplasmin levels may help reduce the risk of thrombosis posed by diminished antithrombin III levels.

Plasma catecholamines and autonomic nervous system function in patients with early renal insufficiency and hypertension: effect of clonidine

Plasma catecholamines, hand-grip exercise and orthostatic stress were used to assess sympathetic nerve function in 14 hypertensive patients with mild to moderate renal failure and, for comparison, in 14 age-matched normal subjects. Furthermore, acute and chronic administrations of clonidine were used to determine a participation of the sympathetic nervous system in the maintenance of hypertension in these patients. Baseline mean blood pressure (MBP), plasma norepinephrine (NE), plasma renin activity (PRA) and aldosterone were elevated in patients with renal failure. During hand-grip exercise, the rise in MBP and in heart rate was blunted in these patients. During orthostasis, MBP decreased more while the increments in NE were greater in hypertensive patients that in normal subjects. Acute administration of clonidine (200 micrograms orally) resulted in a significant decrease in MBP, heart rate, NE, PRA, and aldosterone. There was a significant (p less than 0.01) correlation between the decrease in NE and the fall in MBP. After 6 weeks of treatment, clonidine produced a significant decrease in MBP, heart rate, NE and aldosterone, but not in PRA. Chronic treatment with clonidine produced a slight but significant (p less than 0.05) rise in serum potassium and in serum creatinine. Exchangeable sodium and plasma volume did not change significantly. The data indicate that abnormalities in the function of the sympathetic nervous system are already evident in patients with mild to moderate renal failure. The data also suggest that the sympathetic nervous system may participate in the maintenance of the hypertension in these patients.

Use of noninvasive laboratory testing in the prediction of thrombosis in the nephrotic syndrome

A noninvasive method for diagnosing thrombosis in the nephrotic syndrome could be useful clinically. We measured hematocrit, fibrinogen, creatinine, antithrombin III, plasminogen, and alpha-2-plasmin inhibitor levels in 20 patients with nephrotic syndrome objectively studied for the presence of thrombosis, and found that by using combinations of three or more of these variables good discrimination could be obtained between those patients with and without thrombosis. We conclude that it is possible to predict risk of thrombosis in nephrotic syndrome using relatively simple noninvasive laboratory tests.

Disturbances in the hypothalamic-pituitary-gonadal axis in male patients with acute renal failure

The function of the hypothalamic-pituitary-gonadal (HPG) axis was examined in 20 male patients with acute renal failure. During the oliguric phase of the disease, the serum concentrations of follicle stimulating hormone (FSH) and total and unbound testosterone were markedly reduced, those of prolactin were elevated while those of luteinizing hormone (LH) were normal. The serum concentrations of sex hormone binding globulin were normal. During the diuretic phase of the illness, the serum levels of FSH and testosterone remained low but those of prolactin fell towards normal. After recovery of renal function, the abnormalities in the serum concentrations of these hormones were reversed. The responses of LH and FSH to gonadotropin releasing hormone and of prolactin to thyrotropin releasing hormone were abnormal and became normal after recovery of renal function. The results demonstrate that: (1) abnormalities in HPG axis occur early in the course of acute renal failure; (2) many features of these derangements are similar to those seen in chronic renal failure, and (3) the alterations in the function of the HPG axis are reversible when renal function is restored. The data suggest that loss of renal function, uremia per se and/or a metabolic consequence of uremia such as secondary hyperparathyroidism are responsible for these derangements.

Abnormal relationship between sodium intake and sympathetic nervous system activity in salt-sensitive patients with essential hypertension

To examine the mechanisms underlying the sensitivity to sodium intake in a subset of patients with essential hypertension, we studied the effects of different sodium intake (10, 100, 200 mEq/day) on blood pressure, the function of the renin-angiotensin-aldosterone system, and on blood levels of catecholamines in 20 patients with essential hypertension and 10 normal subjects. Mean blood pressure (MBP) was not different in hypertensive and normal subjects during low sodium diet. But, with high sodium intake, MBP increased by at least 10% in 12 patients (salt-sensitive), whereas in the remaining 8 patients (salt-resistant) and in normal subjects, MBP did not change significantly. This phenomenon cannot be attributed to differences in sodium retention because the percent change in body weight ad the urinary sodium excretion in the salt-sensitive patients was not different than it was in salt-resistant patients or in normal subjects. The observed difference in blood pressure response to high sodium intake in salt-sensitive patients is also not dependent on an impaired suppressibility of the renin-angiotensin-aldosterone system because there were no significant differences in the basal levels of PRA and aldosterone between the groups, and because the orthostatic increments in PRA were significantly lower in salt sensitive than they were in the salt-resistant patients and in normal subjects. Plasma norepinephrine (NE) levels were not significantly different between normal subjects or hypertensive patients while on low sodium intake. But during high sodium intake, they decreased significantly (P less than 0.05) in normal subjects (from 22 +/- 3.4 to 12 +/- 2.3 ng/dl) and in salt-resistant patients (from 17 +/- 4.5 to 13 +/- 2.4 ng/dl) but not in salt-sensitive patients (from 20 +/- 1.9 to 22 +/- 3.2 ng/dl). Furthermore, the majority of salt-sensitive patients displayed inappropriately high plasma NE in relation to their urine excretion of sodium during high sodium intake. Finally, the increments in plasma NE after 5 min of standing were significantly greater in salt-sensitive patients than they were in salt-resistant patients and normal subjects during both low or high sodium intake. These data indicate that a subset of patients with essential hypertension may have impaired suppressibility of plasma NE during high sodium intake, which suggests hyperactivity of the sympathetic nervous system in these patients. These aberrations may be responsible for the increase in MBP in the salt-sensitive patients during high sodium intake.

Autonomic nervous system dysfunction and impotence in uremia

The relationship between abnormalities in nocturnal penile tumescence (NPT) and autonomic function, measured by the Valsalva maneuver, was evaluated in 25 uremic patients and 22 normal subjects. NPT in uremic patients (45 +/- 6.8 min/night) was lower (p less than 0.01) than in normals (85 +/- 10.4 min/night). Valsalva ratio in uremics (1.58 +/- 0.07) was also lower (p less than 0.01) than in normal subjects (2.05 +/- 0.11). NPT and Valsalva ratio were significantly correlated in uremic patients (r = 0.62, p less than 0.01). The 12 uremic patients with abnormal Valsalva maneuver had NPT of 22 +/- 5.2 min/night, a value lower (p less than 0.01) than that (67 +/- 8.7 min/night) observed in the 13 uremic patients with normal Valsalva maneuver. There was also a significant correlation (r = 0.56, p less than 0.05) between the Valsalva ratio and the frequency of intercourse per month in the uremic patients, who had steady and active sexual partners. The data suggest that a dysfunction of the autonomic nervous system may be an important factor in the genesis of erectile abnormalities in patients with uremia.

Alterations of thyroid hormone indices in acute renal failure and in acute critical illness with and without acute renal failure

The present study evaluated thyroid hormone indices of patients with acute renal failure without other systemic illnesses (n = 12), as compared to patients with critical illnesses in the presence (n = 16) and absence (n = 6) of acute renal failure. Abnormalities in the group with acute renal failure alone included decreased serum levels of total T4 and T3, and elevated levels of free rT3. Serum levels of free T4 by equilibrium dialysis and the enzyme immunoassay, T3 uptake ratios, TSH and total rT3 were normal. These findings are consistent with the presence of decreased binding of T4 and rT3 to their serum carrier proteins. Critically ill patients with acute renal failure differed in that they had lower total T4 and T3 levels and elevated T3 uptake ratio values. As in the group with acute renal failure alone, total rT3 levels were normal and free rT3 values were elevated. The group with critical illness alone differed only in that the total rT3 concentrations were elevated in all patients. The alterations of thyroid hormone indices in acute renal failure are similar to those of other nonthyroidal illnesses with the exception of the normal total rT3 levels. This suggests that the failing kidney or the metabolic consequences of uremia specifically affect rT3 metabolism.

Insensitivity of bonnet monkeys to (D-Ala6, Des-Gly10) LHRH ethylamide, a potent new luteinizing hormone releasing hormone analogue in rats and mice

The Luteinizing Hormone Releasing Hormone (LHRH) activity of (D-Ala6, Des-Gly10) LHRH ethylamide was compared with that of LHRH in oöphorectomized bonnet monkeys by determining serum LH and FSH concentrations at various time intervals after a sc injection of 100 mug of LHRH and either 100 mug or 1 mg of the analogue. Following administration of synthetic LHRH, a significant rise in both serum LH and FSH was observed. In contrast, no discernible change in serum gonadotropin concentrations was noted following injection of the analogue (D-Ala6, Des-Gly10) LHRH ethylamide, previously reported to have greatly increased potency in rats and mice.

Activation-induced restoration of sensorimotor functions in rats with dopamine-depleting brain lesions

Bilateral electrolytic lesions of the lateral hypothalamus or intraventricular 6-hydroxydopamine injections produced substantial depletions of striatal dopamine in rates. All animals with brain damage showed marked sensorimotor impairments. However, they began to move and respond appropriately to environmental stimuli when placed in a sink of water, in a shallow ice bath, or among a colony of cats or rats. A reversal of the sensorimotor dysfunctions was still apparent shortly after the animals were removed from each activating situation. However, the terapeutic effects dissipated rapidly, and by 4 hr after an exposure the rats responded as poorly as they had prior to activation. These findings are strikingly similar to the "paradoxical kinesia" seen in parkinsonism, a clinical disorder attributed to degeneration of central dopamine-containing neurons. Collectively, they suggest the importance of activation in maintaining responsiveness to senory stimuli in rats following dopamine-depleting brain lesions.