A unique exon-intron organization of a porcine S100C gene: close evolutionary relationship to calmodulin genes

We found a unique exon-intron structure of the porcine S100C gene, a member of the S100 family, in which all other genes characterized to date have common exon-intron organization. The genomic DNA encoding the porcine S100C was cloned and the entire nucleotide sequence of the gene was analyzed. The gene is present as a single copy and consists of three exons and two introns with a total size of 5.3 kb. The first intron is located after the ATG translation initiation codon. Such an intron has never been found in other S100 genes, but is found in almost all calmodulin genes. The gene structural similarity suggests a close evolutionary relationship between the S100C gene and calmodulin genes.

Extraction of Glycosaminoglycan Peptide from Bovine Nasal Cartilage with 0.1 M Sodium Acetate

Cartilage is a nonedible byproduct with little saleable value, but it is rich in glycosaminoglycan (GAG), which can be converted to a highly profitable product. In this study, GAG was extracted from bovine cartilaginous tissues including nasal cartilage, occipital articular cartilage, and temporomandibular joint disk without using the expensive exogenous proteinase commonly used to extract GAG from tissues. The GAG was extracted with highest yield ( approximately 80% of total tissue uronic acid) by incubating nasal cartilage in 0.1 M sodium acetate, pH 4.5, at 37 degrees C. Tissue autolysis was suggested to occur under the incubation condition to release GAG-peptide. The GAG-peptide purified by DEAE ion-exchange chromatography contained approximately 7% protein, 89% chondroitin sulfate, and 4% keratan sulfate and had no capability to interact with hyaluronic acid. The results suggest that the extraction method with 0.1 M sodium acetate described in this paper is useful for the preparation of GAG-peptide at a low cost.

Effects of egg and yolk weights on yolk antibody (IgY) production in laying chickens

Twenty 35-wk-old chickens, including 10 Single Comb White Leghorn (SCWL) and 10 Rhode Island Red (RIR) hens, were used to examine the effects of egg and yolk weights on egg yolk antibody (IgY) production in the two strains of chickens immunized with BSA. The SCWL chickens had a greater (P < 0.01) percentage hen-day production and greater egg and yolk weights than did the RIR chickens. However, the anti-BSA antibody activities determined by ELISA in the serum and the egg yolk were similar (P > 0.05) between the SCWL and RIR chickens. Similarities between the two strains of hens were also observed in protein and total IgY contents (expressed as the percentage of wet weight of yolk) and the percentage of BSA-specific antibody in the total IgY. It was concluded that both the SCWL and RIR chickens immunized with BSA can produce egg yolk IgY containing similar proportions of BSA-specific antibodies. Therefore, the egg yolk weight and the percentage hen-day production, both of which are greater in the SCWL hens, are considered to be important factors for the efficient production of IgY.

[Changes in hemodynamic state and autonomic nerve function from sleeping to awaking with suggestion on the treatment of cardiovascular diseases]

Effects of sleeping and awaking on blood pressure, heart rate and heart rate variability were shown in normal and a diabetic patient using an ambulatory blood pressure monitor (ABPM), Holter recorder and an accelerometer indicating body motion and posture. From the circadian variation of blood pressure and autonomic nerve function, optimal treatments to protect cardio-vascular accidents were discussed. For the assessments of medication and selection of drugs, ABPM and Holter recording with simultaneous measurement of physical activity are useful.

Acute myositis with transient decrease of albumin, immunoglobulin, and complement following rotavirus gastroenteritis

A 2-year-old boy developed acute myositis associated with rotavirus gastroenteritis. He had remarkable swelling and subcutaneous edema, mostly in the legs, 4 days after the onset of gastroenteritis. Marked elevation of creatine kinase was observed while serum albumin, immunoglobulin, and complement were decreased.

Primary leiomyosarcoma of the pulmonary artery confirmed by catheter suction biopsy

A patient with clinical features consistent with pulmonary embolism showed no improvement despite therapy with tissue-plasminogen activator and full-dose heparin. Transvenous catheter suction biopsy was successful in establishing an antemortem histologic diagnosis of primary pulmonary artery leiomyosarcoma. Urgent surgical intervention was performed.

Residual chromatin breaks as biodosimetry for cell killing by carbon ions

We have studied the relationship between cell killing and the induction of residual chromatin breaks on various human cell lines and primary cultured cells obtained by biopsy from patients irradiated with either X-rays or heavy-ion beams to identify potential bio-marker of radiosensitivity for radiation-induced cell killing. The carbon-ion beams were accelerated with the Heavy Ion Medical Accelerator in Chiba (HIMAC). Six primary cultures obtained by biopsy from 6 patients with carcinoma of the cervix were irradiated with two different mono-LET beams (LET = 13 keV/micrometer, 76 keV/micrometer) and 200kV X rays. Residual chromatin breaks were measured by counting the number of non-rejoining chromatin fragments detected by the premature chromosome condensation (PCC) technique after a 24 hour post-irradiation incubation period. The induction rate of residual chromatin breaks per cell per Gy was the highest for 76 keV/micrometer beams on all of the cells. Our results indicated that cell which was more sensitive to the cell killing was similarly more susceptible to induction of residual chromatin breaks. Furthermore there is a good correlation between these two end points in various cell lines and primary cultured cells. This suggests that the detection of residual chromatin breaks by the PCC technique may be useful as a predictive assay of tumor response to cancer radiotherapy.

Apoptosis induced by heavy ion (carbon) irradiation of two human tumours with different radiosensitivities in vivo: relative biological effectiveness (RBE) of carbon beam

The effect of heavy ion (carbon beam) on apoptosis in vivo was studied. The human brain tumors xenografts of different radiosensitivities were used. The results demonstrated that the effect of carbon beam on apoptosis was similar to photon in radiosensitive tumors; however, carbon beam had the advantage on apoptosis in radioresistant tumors. In ependymoblastoma, a radiosensitive tumor, the incidence of apoptosis induced by photon and by carbon at 6 hours after irradiation were 34.5 +/- 7.85% and 32.5 +/- 7.04%, respectively. In glioblastoma (radioresistant tumor), the incidence of apoptosis induced by photon and by carbon at 6 hours after irradiation were 1.35 +/- 1.68% and 4.4 +/- 2.47%, respectively. Therefore, the incidence of apoptosis was increased more than 3-fold (RBE 3.0) at 6 hours after irradiation in glioblastoma. The heavy ion (carbon) beam is effective in radioresistant tumors in vivo.

Adrenergic-mediated connexin43 phosphorylation in the ocular ciliary epithelium

PURPOSE

Gap junctions provide metabolic cooperativity between the nonpigmented and pigmented cells of the ciliary epithelium. Connexin43 is the major protein of these junctions. To learn whether the phosphorylation state of this gap junction is sensitive to adrenergic mediators, we exposed isolated intact ciliary epithelia to agonists of the G-protein receptor-coupled system and analyzed the phosphorylation state of connexin43 by western blot.

METHODS

The double layer of intact ciliary epithelia was isolated and exposed to isoproterenol, forskolin, and the tumor promoter 12-o-tetradecanoylphorbol-13-acetate (TPA). The phosphorylation state of connexin43 was analyzed by western blot, using a monoclonal antibody that recognized both the phosphorylated and dephosphorylated connexin43. An upward shift in electrophoretic mobility confirmed the presence of a phosphate group.

RESULTS

Connexin43 phosphorylation was rapidly induced by each of these agonists. One microM isoproterenol and 5 microM forskolin induced phosphorylation of connexin43, as did 16 nanomolar TPA. The effect of isoproterenol was partially blocked by 1 microM timolol. Addition of a phosphatase after forskolin treatment reversed the effect of forskolin. Control explant tissue not treated with these agents exhibited a slower but definite phosphorylation of connexin43.

CONCLUSIONS

Phosphorylation of ciliary epithelial connexin43 is sensitive to modulators of the cAMP system as well as an agent that activates PKC. Isolated intact ciliary epithelia phosphorylate connexin43 by endogenous mechanisms, most likely as a protective response to stress.

[Clinical evaluation of heavy-particle radiotherapy using dose volume histogram (DVH)]

Radiotherapy with heavy particles such as proton and heavy-charged particles is a promising modality for treatment of localized malignant tumors because of the good dose distribution. A dose calculation and radiotherapy planning system which is essential for this kind of treatment has been developed in recent years. It has the capability to compute the dose volume histogram (DVH) which contains dose-volume information for the target volume and other interesting volumes. Recently, DVH is commonly used to evaluate and compare dose distributions in radiotherapy with both photon and heavy particles, and it shows that a superior dose distribution is obtained in heavy particle radiotherapy. DVH is also utilized for the evaluation of dose distribution related to clinical outcomes. Besides models such as normal tissue complication probability (NTCP) and tumor control probability (TCP), which can be calculated from DVH are proposed by several authors, they are applied to evaluate dose distributions themselves and to evaluate them in relation to clinical results. DVH is now a useful and important tool, but further studies are needed to use DVH and these models practically for clinical evaluation of heavy-particle radiotherapy.

Biodosimetry of heavy ions by interphase chromosome painting

We report measurements of chromosomal aberrations in peripheral blood lymphocytes from cancer patients undergoing radiotherapy treatment. Patients with cervix or esophageal cancer were treated with 10 MV X-rays produced at a LINAC accelerator, or high-energy carbon ions produced at the HIMAC accelerator at the National Institute for Radiological Sciences (NIRS) in Chiba. Blood samples were obtained before, during, and after the radiation treatment. Chromosomes were prematurely condensed by incubation in calyculin A. Aberrations in chromosomes 2 and 4 were scored after fluorescence in situ hybridization with whole-chromosome probes. Pre-treatment samples were exposed in vitro to X-rays, individual dose-response curves for the induction of chromosomal aberrations were determined, and used as calibration curves to calculate the effective whole-body dose absorbed during the treatment. This calculated dose, based on the calibration curve relative to the induction of reciprocal exchanges, has a sharp increase after the first few fractions of the treatment, then saturates at high doses. Although carbon ions are 2-3 times more effective than X-rays in tumor sterilization, the effective dose was similar to that of X-ray treatment. However, the frequency of complex-type chromosomal exchanges was much higher for patients treated with carbon ions than X-ray.

[Survival in patients with clear cell carcinoma of the ovary]

Thirty-one patients with clear cell ovarian carcinoma who underwent primary surgery and postoperative therapy were retrospectively evaluated. Eighteen patients (58%) had International Federation of Gynecology and Obstetrics (FIGO) stage I disease, 3 patients (9.7%) stage II disease, and 10 patients (32.3%) stage III and IV disease. Patients with stage III and IV disease demonstrated a significantly poor prognosis compared with patients who had stage I or II disease (p < 0.01). No patients with stage III and IV disease survived 5 years. p53 protein expression and proliferative activity (PA) were studied by immunohistochemical methods using p53 molecule and antibodies to PCNA (proliferative cell nuclear antigen). Intranuclear accumulations of p53 product were observed in 15 of 31 (48.4%). On the other hand, 15 of 31 (48.4%) patients stained positively for PCNA (> or = 60% of cancer cells stained positively). Positive p53 staining and highly PA were associated with poor survival. Two patients with stage I a relapsed were positive p53 and highly PA. Accordingly, consolidation chemotherapy is necessary for patients with stage I a who are positive p53 and highly PA. Platinum-based chemotherapy for patients who had minimal residual tumor was effective, but 5 patients who had > or = 2 cm tumor burden were not effective at all. The response rate for platinum-based chemotherapy was 20% (1/5) among p53 positive, in contrast to 66.7% (4/6) among p53 negative patients. So it seems that p53 positive patients are chemoresistant.

Expression of telomerase activity in human chorion

Telomerase activation is required for cellular immortalization and is found in most malignant tumors. Normal somatic cells are generally telomerase-negative, except for stem cells in renewing tissues. During pregnancy, human trophoblast continues to proliferate and acts as proliferating stem cells for the development of chorion and the formation of placenta. In the present study, a total of 105 chorions from placentas at various weeks of gestation were examined for telomerase activity using the telomeric repeat amplification protocol (TRAP) assay. Twenty-five of 33 (76%) normal early chorions at 5 to 9 weeks gestation were telomerase-positive. Chorions from early spontaneous abortions also exhibited telomerase activity but at a low level. In contrast, only 2 (4%) late chorions at 34 to 41 weeks gestation expressed telomerase activity. Significant telomerase activity was observed in trophoblast cell fractions of chorion, demonstrating trophoblast to be the source of the activity. Expression of human telomerase catalytic subunit (hTRT) was observed in early chorions, but not in late placenta, and there was a close correlation between telomerase activity and hTRT expression. In contrast, expression of human telomerase RNA component (hTR) was observed in both early and late chorions and was not liked to telomerase activity. These findings suggest that telomerase activity in chorion is critically regulated over the course of gestation, associated with hTRT expression. The findings of the present study also appear to support the emerging concept that normal somatic cells with stem cell-like characteristics can express telomerase activity.

Nuclear translocation of gold labeled-testosterone-bovine serum albumin conjugate through the nuclear double membranes in rat spermatids

We have demonstrated that testosterone-bovine serum albumin conjugate labeled with 2-nm colloidal gold (testosterone-BSA-gold) injected into the vascular system of rat becomes visible as silver deposits on the sections of tissues embedded in epoxy resin after silver enhancement and enters the androgen-target cell nuclei, e.g. round spermatids, but not the non-target cell nuclei. The diameter of the silver deposits depends on the duration of silver enhancement. In this study, to make clear the transfer route of testosterone-BSA-gold into the round spermatid nucleus, the testis of rat injected testosterone-BSA-gold was observed under electron microscope after silver enhancement for short periods of time. The small silver deposits were present on the cell membrane, vesicles, Golgi region, acrosome, subacrosomal space, both the post-acrosomal and the subacrosomal nuclear envelope, and the nucleoplasm in the cap-phase spermatids. The silver deposits were also found in the perinuclear cisterna of post-acrosomal nuclear envelope, but not in the nuclear pore. When the spermatids were observed at high-power magnification without the silver enhancement, the outer nuclear membrane showed many irregular invaginations toward the inner nuclear membrane in the post-acrosomal nuclear envelope. Furthermore, a double-membrane-like vesicle seemed to be present in the nuclear envelope. In the vesicle, the gold particles were present along the inner membrane. These results suggest that testosterone-BSA-gold can enter the nucleoplasm through some route provided by the nuclear double membranes in both the post-acrosomal and the subacrosomal nuclear envelope.

Genotype of GB virus C/hepatitis G virus by molecular evolutionary analysis

GB virus C/hepatitis G virus is a newly described virus. Classification of GB virus C/hepatitis G virus into genotypes has not been established. We analyzed nucleotide sequences within the 5' untranslated region of GB virus C/hepatitis G virus isolates and segregated these isolates into genotypes. Twenty serum samples with GB virus C/hepatitis G virus RNA from Australia, Cameroon, the Congo, Japan, Mongolia, and Bangladesh were studied. Reverse transcription and polymerase chain reaction were used to obtain GB virus C/hepatitis G virus RNA. After nucleotide sequences from the 5' untranslated region were determined, 68 nucleotide sequences, including 48 previously reported sequences, were analyzed by molecular evolutionary methods. The phylogenetic tree of the 5' untranslated region showed that all strains could be divided into three major genotypes, GB type (type 1), HG type (type 2), and Asian type (type 3). Bootstrap analysis indicated that the strains could be divided into three major genotypes but could not be further subdivided. Moreover, frequency histograms of pairwise distances between nucleotide sequences demonstrated only one peak. These result indicated that GB virus C/hepatitis G virus can be classified into three major genotypes, GB type (type 1), HG type (type 2), and Asian type (type 3), and should not be divided into minor subtypes.

Glycosaminoglycans from growing antlers of wapiti (Cervus elaphus)

The emerging wapiti industry in North America is based largely on markets for velvet antlers which are used in oriental medicine. Despite the economic opportunity, enthusiasm has been dampened by incomplete understanding of the chemical and pharmacological properties of velvet antler. This study characterizes polysaccharide constituents of glycosaminoglycans in growing antler of wapiti (Cervus elaphus). Glycosaminoglycans were isolated from four sections (tip, upper, middle and base) of growing antlers, and were studied using cellulose acetate electrophoresis, gel electrophoresis, enzymatic digestion and gel chromatography. The tip and upper sections of the antler which are rich in cartilaginous tissues contained chondroitin sulfate as a major glycosaminoglycan with small amounts of hyaluronic acid. In the middle and base sections containing bone and bone marrow, chondroitin sulfate was also a major glycosaminoglycan with small amounts of hyaluronic acid and chondroitinase-ACI resistant materials. More than half of chondroitin sulfate from the middle and base sections had larger molecular size than did the chondroitin sulfates from the tip and upper sections. Key words: Glycosaminoglycans, chondroitin sulfate, antler, wapiti

Circadian rhythm estimation by core body temperature filtered with simultaneously recorded physiological data

In field measurements, monitoring of core body temperature is influenced by physical activities; therefore, the estimation of circadian rhythm from the data may not be exact. The purpose of this study is to design a core body temperature filter in order to reduce artifacts induced by physical activities using simultaneously recorded physiological data such as heart rate data. The effects of physical activities on core body temperature and heart rate are assessed through three experiments. Based on the above knowledge, a core body temperature filter was designed. The filter removes part of rectal temperature data as artifact when heart rate rises above a predetermined threshold. As a result, most of the spike-like noise was removed and the filtered temperature data showed sinusoidal variation more than the unfiltered data. The mesor of the estimated rhythm significantly decreased. This filtering method can provide more precise information about circadian rhythm, especially in field measurements.

Radiation dosimetry measurements with real time radiation monitoring device (RRMD)-II in Space Shuttle STS-79

The real-time measurement of radiation environment was made with an improved real-time radiation monitoring device (RRMD)-II onboard Space Shuttle STS-79 (S/MM#4: 4th Shuttle MIR Mission, at an inclination angle of 51.6 degrees and an altitude of 250-400km) for 199 h during 17-25 September, 1996. The observation of the detector covered the linear energy transfer (LET) range of 3.5-6000 keV/micrometer. The Shuttle orbital profile in this mission was equivalent to that of the currently planned Space Station, and provided an opportunity to investigate variations in count rate and dose equivalent rate depending on altitude, longitude, and latitude in detail. Particle count rate and dose equivalent rate were mapped geographically during the mission. Based on the map of count rate, an analysis was made by dividing whole region into three regions: South Atlantic Anomaly (SAA) region, high latitude region and other regions. The averaged absorbed dose rate during the mission was 39.3 microGy/day for a LET range of 3.5-6000 keV/micrometer. The corresponding average dose equivalent rates during the mission are estimated to be 293 microSv/day with quality factors from International Commission on Radiological Protection (ICRP)-Pub. 60 and 270 microSv/day with quality factors from ICRP-Pub. 26. The effective quality factors for ICRP-Pub. 60 and 26 are 7.45 and 6.88, respectively. From the present data for particles of LET > 3.5keV/micrometer, we conclude that the average dose equivalent rate is dominated by the contribution of galactic cosmic ray (GCR) particles. The dose-detector depth dependence was also investigated.

Measurements of LET distribution and dose equivalent onboard the Space Shuttle IML-2 (STS-65) and S/MM#4 (STS-79)

Space radiation dosimetry measurements have been made onboard the Space Shuttle STS-65 in the Second International Microgravity Laboratory (IML-2: 28.5 degrees x 300 km: 14.68 days) and the STS-79 in the 4th Shuttle MIR mission (S/MM#4: 51.6 degrees x 300-400km: 10.2 days). In these measurements, three kinds of detectors were used; one is a newly developed active detector telescope called "Real-time Radiation Monitoring Device (RRMD-I for IML-2 and RRMD-II with improved triggering system for S/MM#4)" utilizing silicon semi-conductor detectors and the other detectors are conventional passive detectors of thermoluminescence dosimeters (TLDs) and CR-39 plastic track detectors. The main contribution to dose equivalent for particles with LET > 5.0 keV/micrometer (IML-2) and LET > 3.5 keV/micrometer (S/MM#4) is seen to be due to galactic cosmic rays (GCRs) and the contribution of the South Atlantic Anomaly (SAA) is less than 5% (IML-2: 28.5 degrees x 300 km) and 15% (S/MM#4: 51.6 degrees x 400 km) in the above RRMD LET detection conditions. For the whole LET range (> 0.2 kev/micrometer) obtained by TLDs and CR-39 in these two typical orbits (a small inclination x low altitude and a large inclination x high altitude), absorbed dose rates range from 94 to 114 microGy/day, dose equivalent rates from 186 to 207 microSv/day and average quality factors from 1.82 to 2.00 depending on the locations and directions of detectors inside the Spacelab at the highly protected IML-2 orbit (28.5 degrees x 300 km), and also, absorbed dose rates range from 290 to 367 microGy/day, dose equivalent rates from 582 to 651 microSv/day and average quality factors from 1.78 to 2.01 depending on the dosimeter packages around the RRMD-II "Detector Unit" at the S/MM#4 orbit (5l.6 degrees x 400km). In general, it is seen that absorbed doses depend on the orbit altitude (SAA trapped particles contribution dominant) and dose equivalents on the orbit inclination (GCR contribution dominant). The LET distributions obtained by two different types of active and passive detectors, RRMDs and CR-39, are in good agreement for LET of 15 - 200 kev/micrometer and difference of these distributions in the regions of LET < 15 kev/micrometer and LET > 200 kev/micrometer can be explained by considering characteristics of CR-39 etched track formation especially for the low LET tracks and chemical etching conditions.

Cell adhesion to phosphatidylserine mediated by a product of growth arrest-specific gene 6

Gas6, a product of a growth arrest-specific gene 6, potentiates proliferation of vascular smooth muscle cells and prevents cell death of vascular smooth muscle cells. It has been also demonstrated that Gas6 is a ligand of receptor tyrosine kinases Axl, Sky, and Mer. Gas6 contains gamma-carboxyglutamic acid residues, which are found in some blood coagulation factors and mediate the interaction of the coagulation factors with negatively charged phospholipid. In this study, we clarified that Gas6 specifically bound to phosphatidylserine and the binding was dependent on Ca2+ and gamma-carboxyglutamic acid residues. Furthermore, we found that U937 cells, which express Gas6 receptor on their surfaces, adhered to phosphatidylserine-coated enzyme-linked immunosorbent assay (ELISA) plate only in the presence of Gas6 and Ca2+. U937 cells also bound to ELISA plate coated with phosphatidylinositol, but the binding was independent of Gas6 and Ca2+. On the other hand, U937 cells did not adhere to phosphatidylcholine- or phosphatidylethanolamine-coated ELISA plate even in the presence of Gas6 and Ca2+. These findings suggest that Gas6 may play a role in recognition of cells exposing phosphatidylserine on their surfaces by phagocytic cells, which is supposed to be one of the mechanisms for clearing dying cells.

Regulation of myosin phosphatase through phosphorylation of the myosin-binding subunit in platelet activation

Human platelets were found to contain myosin phosphatase consisting of a 38-kD catalytic subunit of protein phosphatase type 1delta, a 130-kD myosin-binding subunit (MBS) and a 20-kD subunit, all of which cross-reacted with antibodies against these subunits of smooth muscle myosin phosphatase. Anti-MBS antibody coimmunoprecipitated RhoA and Rho-kinase of human platelets. Platelets MBS is a substrate for Rho-kinase and phosphorylation of MBS decreases the activity of myosin phosphatase. Treatment of intact platelets with 9, 11-epithio-11,12-methano-thromboxane A2 led to a dramatic increase in phosphorylation of MBS and a significant decrease in the activity of myosin phosphatase. These findings suggest a putative mechanism for agonist-induced regulation of myosin phosphatase activity in platelets.

Comparison of [123I]metaiodobenzylguanidine kinetics with heart rate variability and plasma norepinephrine level

BACKGROUND

[123I]Metaiodobenzylguanidine (MIBG) imaging has been used to assess cardiac sympathetic nerve abnormalities. We evaluated the clinical significance of myocardial MIBG imaging as a measure of cardiac sympathetic nervous system function by comparing it to heart rate variability and plasma norepinephrine level.

METHODS AND RESULTS

In 211 subjects, we analyzed heart rate variability with 24-hour electrocardiography, performed scintigraphy with MIBG, and measured plasma norepinephrine levels. Time and frequency domain measures of heart rate variability were calculated with the Marquette heart rate variability program (Marquette Electronics, Milwaukee, Wis.). Early and late myocardial MIBG uptakes were measured at 15 and 150 minutes after injection, respectively. MIBG clearance rate from the heart and heart-to-lung and heart-to-mediastinum ratios of MIBG activities were calculated. On the whole, heart rate variability, including low-frequency power, correlated positively, but modestly so, with late MIBG uptake and negatively with MIBG clearance rate. The plasma norepinephrine level correlated negatively with late MIBG uptake and with heart rate variability, including low-frequency power, and positively with MIBG clearance rate. Similar correlations were also observed in patient subgroups with coronary artery disease, diabetes mellitus, and renal failure, but these correlations were weak (R2 < 0.5).

CONCLUSIONS

Increased cardiac sympathetic nervous system activity may be associated with increased myocardial MIBG clearance and decreased heart rate variability, including low-frequency power. Because these associations were not strong, however, the combination of heart rate variability with MIBG may allow an interactive assessment of the cardiac autonomic nervous system.