Patterns of cardiovascular reactivity in disease diagnosis.

BACKGROUND: Aberrations of cardiovascular reactivity (CVR), an expression of autonomic function, occur in a number of clinical conditions, but lack specificity for a particular disorder. Recently, a CVR pattern particular to chronic fatigue syndrome was observed. AIM: To assess whether specific CVR patterns can be described for other clinical conditions. METHODS: Six groups of patients, matched for age and gender, were evaluated with a shortened head-up tilt test: patients with chronic fatigue syndrome (CFS) (n = 20), non-CFS fatigue (F) (n = 15), neurally-mediated syncope (SY) (n = 21), familial Mediterranean fever (FMF) (n = 17), psoriatic arthritis (PSOR) (n = 19) and healthy subjects (H) (n = 20). A 10-min supine phase was followed by recording 600 cardiac cycles on tilt (5-10 min). Beat-to-beat heart rate (HR) and pulse transit time (PTT) were measured. Results were analysed using conventional statistics, recurrence plot analysis and fractal analysis. RESULTS: Multivariate analysis evaluated independent predictors of the CVR in each patient group vs. all other groups. Based on these predictors, equations were determined for a linear discriminant score (DS) for each group. The best sensitivities and specificities of the DS, consistent with disease-related phenotypes of CVR, were noted in the following groups: CFS, 90.0% and 60%; SY, 93.3% and 62.5%; FMF, 90.1% and 75.4%, respectively. DISCUSSION: Pathological disturbances may alter cardiovascular reactivity. Our data support the existence of disease-related CVR phenotypes, with implications for pathogenesis and differential diagnosis.

The head-up tilt test with haemodynamic instability score in diagnosing chronic fatigue syndrome.

BACKGROUND: Studying patients with chronic fatigue syndrome (CFS), we have developed a method that uses a head-up tilt test (HUTT) to estimate BP and HR instability during tilt, expressed as a 'haemodynamic instability score' (HIS). AIM: To assess HIS sensitivity and specificity in the diagnosis of CFS. DESIGN: Prospective controlled study. METHODS: Patients with CFS (n=40), non-CFS chronic fatigue (n=73), fibromyalgia (n=41), neurally mediated syncope (n=58), generalized anxiety disorder (n=28), familial Mediterranean fever (n=50), arterial hypertension (n=28), and healthy subjects (n=59) were evaluated with a standardized head-up tilt test (HUTT). The HIS was calculated from blood pressure (BP) and heart rate (HR) changes during the HUTT. RESULTS: The tilt was prematurely terminated in 22% of CFS patients when postural symptoms occurred and the HIS could not be calculated. In the remainder, the median(IQR) HIS values were: CFS +2.14(4.67), non-CFS fatigue -3.98(5.35), fibromyalgia -2.81(2.62), syncope -3.7(4.36), generalized anxiety disorder -0.21(6.05), healthy controls -2.66(3.14), FMF -5.09(6.41), hypertensives -5.35(2.74) (p<0.0001 vs. CFS in all groups, except for anxiety disorder, p=NS). The sensitivity for CFS at HIS >-0.98 cut-off was 90.3% and the overall specificity was 84.5%. DISCUSSION: There is a particular dysautonomia in CFS that differs from dysautonomia in other disorders, characterized by HIS >-0.98. The HIS can reinforce the clinician's diagnosis by providing objective criteria for the assessment of CFS, which until now, could only be subjectively inferred.

Assessment of cardiovascular reactivity by fractal and recurrence quantification analysis of heart rate and pulse transit time.

Methods used for the assessment of cardiovascular reactivity are flawed by nonlinear dynamics of the cardiovascular responses to stimuli. In an attempt to address this issue, we utilized a short postural challenge, recorded beat-to-beat heart rate (HR) and pulse transit time (PTT), assessed the data by fractal and recurrence quantification analysis, and processed the obtained variables by multivariate statistics. A 10-min supine phase of the head-up tilt test was followed by recording 600 cardiac cycles on tilt, that is, 5-10 min. Three groups of patients were studied, each including 20 subjects matched for age and gender--healthy subjects, patients with essential hypertension (HT), and patients with chronic fatigue syndrome (CFS). The latter group was studied on account of the well-known dysautonomia of CFS patients, which served as contrast against the cardiovascular reactivity of the healthy population. A total of 52 variables of the HR and PTT were determined in each subject. The multivariate model identified the best predictors for the assessment of reactivity of healthy subjects vs CFS. Based on these predictors, the "Fractal & Recurrence Analysis-based Score" (FRAS) was calculated: FRAS=76.2+0.04*HR-supine-DET -12.9*HR-tilt-R/L -0.31*HR-tilt-s.d. -19.27*PTT-tilt-R/L -9.42*PTT-tilt-WAVE. The median values and IQR of FRAS in the groups were: healthy=-1.85 (IQR 1.89), hypertensives=+0.52 (IQR 5.78), and CFS=-24.2 (5.34) (HT vs healthy subjects: P=0.0036; HT vs CFS: P<0.0001). Since the FRAS differed significantly between the three groups, it appears likely that the FRAS may recognize phenotypes of cardiovascular reactivity.

Schistosomiasis: role of endogenous opioids in suppression of gonadal steroid secretion.

1. Radioimmunoassay of the opiate, beta-endorphin, in mouse sera, indirect measurement of estrogen by examination of vaginal smears and indirect measurement of androgens by electrophoresis of major urinary proteins (MUP) revealed that beta-endorphin increases while estrogen and androgen levels decrease in mice with chronic Schistosoma mansoni infection. 2. Injections of the opiate antagonist, naltrexone, reversed the effects of schistosomiasis on estrogen and androgen levels. 3. Because opiates are known to inhibit the secretion of releasing hormones by the hypothalamus, the data suggest that the inhibition of hypothalamic-pituitary-gonadal function that occurs in chronically infected male and female mice results from excessive beta-endorphin. 4. It is also suggested that the excessive beta-endorphin may be secreted by T-lymphocytes and possibly macrophages involved in the cell-mediated immune response (CMIR) to the ova.

Phorbol ester modulates interleukin 6- and interleukin 1-regulated expression of acute phase plasma proteins in hepatoma cells.

Interleukin 6 (IL 6) and interleukin 1 (IL-1) regulate the expression of acute phase plasma proteins in rat and human hepatoma cells. Phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), partially mimics the stimulatory effect of IL-6 but reduces that effect of IL-1. TPA and IL-6 act synergistically. These regulatory properties of TPA are also manifested in HepG2 cells transiently transfected with an indicator gene construct carrying the IL-1/IL-6 regulatory enhancer element of the rat alpha 1-acid glycoprotein gene. IL-6 and IL-1 act independently of TPA-inducible kinase C, and of changes in intracellular Ca2+ concentrations. However, prolonged pretreatment of HepG2 cells with TPA results in a drastically reduced cytokine response that is proportional to the loss of cell surface binding activity for the cytokine. These data suggest that hormones activating protein kinase C probably play a contributing role in stimulating the expression of acute phase plasma protein genes but they may be crucial in controlling the responsiveness of liver cells to inflammatory cytokines during subsequent stages of the hepatic acute phase reaction.

Effects of Schistosoma mansoni on androgen regulated gene expression in the mouse.

Two-dimensional gel electrophoresis of liver mRNA translation products and dot-blot hybridization revealed that the levels of mRNA encoding major urinary proteins were greatly reduced in mice infected with Schistosoma mansoni. Major urinary protein mRNA levels are known to be androgen regulated. Dot-blot hybridization analysis of RNAs from various mouse tissues with a variety of cDNA probes indicated that all androgen-regulated mRNAs tested were reduced in infected mice. Administration of testosterone to infected animals restored urinary major urinary protein levels. Direct measurement of serum testosterone levels and seminal vesicle weights confirmed that chronic schistosome infection reduces testosterone to castration levels in male mice.

Fasciola hepatica: collagen deposition and other histopathology in the rat host's bile duct caused by the parasite and by proline infusion.

Bile ducts were examined histochemically to compare the effects of proline infusion with Fasciola hepatica implantation in rats. After 3 weeks of infusion or implantation, both proline and F. hepatica produced increases in the luminal perimeter and collagen content of the bile duct. However, the effect of the parasite was significantly greater than that of proline, and the parasite produced significant increases in the bile duct wall. These results corroborate earlier biochemical and histological studies indicating the important role of proline in the enlargement of the bile duct in fascioliasis.

Proline induced hemolytic anemia in fascioliasis.

A secondary anemia is characteristic of infections with the liver fluke, Fasciola hepatica, and previous studies had suggested that proline released by the worm might be involved in producing this condition. In the current study the effect of fascioliasis on erythropoiesis was compared to the effects of proline infusion. Both treatments produced effects characteristic of rapid erythrocyte turnover due to hemolysis. Moreover, infusion of a proline analog into animals with Fasciola or into animals infused with proline prevented the anemia. To our knowledge the production of hemolytic anemia by excessive proline has not been previously reported.

Levels of type I and type III collagen in the bile duct of rats infected with Fasciola hepatica.

Collagen types and their levels were compared between bile ducts from Fasciola infected rats and bile ducts from uninfected animals. Both collagen types I and III were shown to be increased in infected animals but, levels of type I increased less than type III. These results indicate that fascioliasis produces changes in the collagen composition of the bile duct that are similar to those produced in cirrhosis of the liver and other pathologic conditions including wound healing. Such observations suggest that a study of the chronology of collagen deposition in fascioliasis might provide information on the sequence of molecular events which result in bile duct hyperplasia.

Schistosomiasis: proline production and release by ova.

The production and release of proline was measured in cleaned ova of Schistosoma mansoni. Proline was found to be released at approximately 76 mumoles/100 cc of ova water/hr. This high rate of proline production was found to correlate with extremely active proline synthetic enzymes in the ova. Ornithine-delta-transaminase, which converts ornithine to delta 1-pyrroline-5-carboxylic acid, was found to be twice that of adult schistosomes and over seven times that of rat liver. delta 1-pyrroline-5-carboxylic acid reductase, which converts delta 1-pyrroline-5-carboxylic acid to proline, is also more active than the adult isoenzyme and 35 times more active than the rat liver isoenzyme. These data suggest that proline emanating from the ova may play a role in stimulating fibrosis in the granulomata of schistosomiasis.

Fascioliasis: bile duct collagen induced by proline from the worm.

We investigated whether collagen increases occur in the bile duct during fascioliasis, and their relationship to the release of proline by the worm. Experiments showed increased levels of collagen in the bile ducts of rats following 2 wk of infusion with proline or i.p. implantation with Fasciola. The increase in bile duct collagen in proline-infused animals and in worm-implanted animals could be completely inhibited to the amount in controls by 3,4-dehydroproline. These effects suggest that the hyperplasia of the bile duct that is induced by liver flukes involves stimulation of collagen deposition through their release of proline.

Facioliasis: is the anemia caused by hematophagia?

In fascioliasis, anemia is a well-recognized symptom but its etiology is controversial. There is disagreement on whether hematophagia occurs, and if it does, whether it is sufficient to produce the anemic symptoms observed. Another opinion is that a toxic substance emanating from the fluke causes the anemia. In the present study the anemia was investigated in rats. Hematological parameters measured over the course of infection showed significant decreases in erythrocyte counts and hemoglobin after the flukes entered the bile duct. Significant increases were observed in reticulocyte counts and mean corpuscular volume upon entry of flukes into the bile duct. Urobilinogen levels increased in early stages of infection but returned to near normal levels after the worms reached the bile duct. To determine whether Fasciola hepatica could produce an anemia in rats when hematophagia was prevented, uninfected rats were peritoneally implanted with worms in fine-mesh sacks which prevented worms from feeding on blood. Hematological parameters indicated that the anemia produced in rats with implanted worms was very similar to that produced by mature, per os infections. This study indicates that the anemia is caused by a substance released by the worms and supports previous work suggesting that proline released from the worms may be inducing the anemia.

Fascioliasis: similarities of the anemia in rats to that produced by infused proline.

Fasciola hepatica releases large amounts of proline into the bile of its host. Significant increases in the levels of other amino acids in the bile also occur. The present investigation examines whether proline and these other amino acids may play a role in inducing the anemia that frequently accompanies fascioliasis. In experiments, rats were infused intra-abdominally for 2 weeks with 1 of 3 solutions: 20.0 mM proline in saline, a mixture of 8 amino acids (excluding proline) each at 2.0 mM in saline, or saline only. At the end of the experiments 2 cc of blood was removed from each rat, via cardiac puncture. The heparinized blood was used to count erythrocytes and reticulocytes, and to measure hematocrit and mean corpuscular volume (MCV). Analysis of variance disclosed highly significant differences in erythrocyte counts, MCV, and reticulocyte counts among the 5 groups. A Student-Newman-Keuls test indicated that the Proline and Infected groups were not different from each other (except for MCV, where proline's effect was more severe) and that both groups differed significantly from the Amino Acid group, the Saline group, and the Control group. Hence, it appears that infused proline can cause an anemia similar to that induced by Fasciola.

Fascioliasis: nitrogen balance studies and the disposition of excessive proline in rats.

Nitrogen balance studies were conducted and the results compared between rats infected with Fasciola hepatica and uninfected rats as follows: Rats with 90 to 100 day infections were randomly selected and then matched by weight to uninfected controls. All rats were then fed a 6% protein diet for 3 days. Nitrogen balance data indicated that infected rats excreted significantly higher urinary nitrogen than the healthy ones. As large quantities of proline were known to be released into the host in fascioliasis it was suggested that the excessive proline might cause depressed nitrogen balance. In view of this possibility and because any pathological effects of the excessive proline would likely be most apparent in the organs involved in its handling, a proline disposition study was carried out. For this part of the study, the levels of the proline in various regions of the gut, the urine, the feces and the portal blood of both infected and control rats were measured and compared. Proline levels were found to be elevated in portal blood, duodenal contents, colonic contents, urine and feces.

Fascioliasis: role of proline in bile duct hyperplasia.

In animals fascioliasis, extensive hyperplasia of the main bile duct occurs that often results in enlargement of the duct to more than 20 times the normal. We report that proline infused into the abdominal cavity of rats caused hyperplasia of the bile duct resembling that produced in the early stages of the disease. We suggest that Fasciola hepatica, which synthesizes and releases large amounts of proline, induces enlargement of the bile duct by a similar mechanism.