Combined study with FDG PET and Tl SPECT in patients with idiopathic dilated cardiomyopathy

This study aimed to determine whether combined examinations of myocardial 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) and stress-redistribution 201Tl single-photon emission computed tomography (Tl SPECT) were useful in clarifying myocardial ischaemia and evaluating the prognosis in patients with idiopathic dilated cardiomyopathy (IDCM). Twenty-two patients with IDCM underwent echocardiography, cardiac catheterization, FDG PET, and Tl SPECT. In scintigraphic analysis, the total defect score (TDS) was semiquantitatively determined as the sum of scores of the 17 left ventricular (LV) segments with a 5-point scale (0 as normal to 4 as absent). Patients were classified according to the scintigraphic findings as follows: eight patients with small defects on Tl and FDG (TDS < or = 20) (group I), eight patients with small defects on FDG (TDS < or = 20) with FDG uptake increased relative to Tl or 'mismatch' (group II), and six patients with large defects on FDG and Tl (TDS >20) (group III). Eleven patients (50%) showed reversible defects on Tl and all showed preserved FDG uptake. The patients in group III had significantly lower LV ejection fraction (LVEF) (P<0.05, respectively) and a poorer prognosis as shown by the Kaplan-Meier event-free curve compared with those in groups I and II (P<0.01, respectively). Although patients in group II had significantly greater TDS on Tl compared with those in group I (P<0.01), no significant differences in LVEF and prognosis were found between patients in groups I and II. In multivariate analysis, a TDS on FDG revealed an independent predictor of subsequent cardiac events. In conclusion, such mismatched areas can be assumed to consist of impaired but viable myocardium, and may be associated with ischaemia of the microvasculature. Impaired myocardial glucose metabolism is a more powerful predictor of future cardiac events than perfusion abnormality in patients with IDCM.

Characterization of "unhealed gastric ulcers" produced with chronic exposure of acetic acid ulcers to indomethacin in rats

We previously discovered that a 4-wk course of indomethacin delivered to rats with acetic acid ulcers resulted in production of "unhealed gastric ulcers" that persisted for up to 12 wks after treatment cessation. The present study examined the mechanism underlying such "unhealed gastric ulcers" with biochemical and histological procedures. "Unhealed gastric ulcers" were induced with a 4-wk indomethacin treatment (1 mg/kg, twice daily) in rats with acetic acid ulcers. Two and 4 wks after treatment cessation, ulcer size was significantly larger in rats receiving indomethacin compared with control animals. Ulcerated tissue prostaglandin E2 levels were significantly lower during indomethacin treatment, but the levels tended to increase after treatment cessation compared with levels measure in the group receiving vehicle. Myeloperoxidase activity levels were significantly higher during indomethacin treatment; such levels persisted after treatment cessation. Histologically, greater degrees of fibrosis and neutrophil accumulation, as well as a lesser degree of angiogenesis were observed in the "unhealed gastric ulcers" compared to ulcers that healed in a normal fashion. It was concluded that severe fibrosis, persistent neutrophil infiltration, and poor angiogenesis in the ulcer base might represent factors involved in the mechanism underlying production of "unhealed gastric ulcers".

[New surgical approach "intrapulmonary septation technic" for Fontan candidates with unilateral pulmonary arterial hypoplasia and/or pulmonary venous obstruction]

Unilateral pulmonary arterial hypoplasia and/or pulmonary venous obstruction are serious hazards for Fontan candidates. For these patients, we have started new surgical approach "intrapulmonary septation technic". This consists of 3 components; (A) partial right heart bypass to well-grown side, (B) mandatory pulmonary blood flow to low-capacity side, (aorto-pulmonary shunt or others) and (C) a patch between partial right heart bypass and mandatory pulmonary blood flow. Thirteen patients underwent the approach. The source of partial right heart bypass was brought from superior vena cava (11 patients), inferior vena cava (1 patient) and fenestrated Fontan (1 patient). The mandatory pulmonary blood flow was supplied by aorto-pulmonary shunt (11 patients), pulmonary arterial banding (1 patient) and native pulmonary valve stenosis (1 patient). We added pulmonary artery enlargement (9 patients), release of pulmonary venous obstruction (8 patients) and/or atrio-ventricular valve plasty (5 patients), simultaneously. No hospital death. Early post-operative course was uneventful in all cases except 1, as pulmonary blood flow to low-capacity side had increased gradually after this intervention. Eight patients had reached Fontan operation. In this approach, nearly whole pulmonary artery can grow without any affect of volume overload through well-grown side from collateral arteries of low-capacity side. All procedures of "intrapulmonary septation technic" and reconstruction of pulmonary artery in Fontan operation can be easily performed in larger pulmonary artery of well-grown side, eliminating need for extensive dissection.

CTAD as a universal anticoagulant

The feasibility of CTAD (a mixture of citrate, theophylline, adenosine and dipyridamole) as a new anticoagulant for medical laboratory use was studied prospectively. Whole blood anticoagulated with CTAD exhibited results very similar to those of blood anticoagulated with EDTA on complete blood count and automated white cell differential except for a slight decrease in platelet count and mean platelet volume. Chemistry test data for plasma obtained from CTAD whole blood were close to those obtained for matched sera. Among coagulation tests, prothrombin time, activated partial thromboplastin time and fibrinogen concentrations were close to those obtained with citrate plasma. Based on the results, CTAD was judged to be a good candidate as a new anticoagulant.

Finite element analysis of the possible mechanism of cervical lesion formation by occlusal force

Recently, various authors have proposed the interesting idea that occlusal force may be a principal factor in cervical lesions of the tooth. It is speculated that the lateral force in non-ideal mastication causes the tooth to bend and that the resulting tensile stress damages the enamel surface. In this study, we carried out stress analysis on the upper central incisor and the lower first molar using the plastic-elastic deformation theory with two-dimensional finite element method (FEM). The essential feature that the tensile yield strength is much smaller than the compressive one was taken into account. Our results suggested that oblique loading on the tooth stretches the enamel surface near the cemento-enamel junction and causes plastic deformation which eventually leads to the cervical lesion.

Prognosis is predicted by early hearing improvement in patients with idiopathic sudden sensorineural hearing loss

The time-course of the recovery of the hearing level after treatment in 90 patients with idiopathic sudden sensorineural hearing loss was examined. The improvement rate calculated relative to the hearing level of the opposite ear was investigated to estimate the hearing recovery. Follow-up audiograms were performed once per week for 1 month after treatment and once per month thereafter. There were two groups that differed with respect to the characteristics of hearing recovery. One group showed an improvement rate of over 50% at 1-2 weeks and a good improvement rate at 3 months after treatment. In the other group, the improvement rate did not reach 50% at 1-2 weeks, and the improvement rate was poor at 3 months after treatment. The patients with improvement rates of over 50% at 1-2 weeks had earlier initial visits and had mild hearing loss, whereas the patients with profound hearing loss had improvement rates under 50% and poor long-term prognosis. We conclude that the improvement rate at 1-2 weeks after treatment predicts the long-term prognosis for recovery of hearing level in patients with sudden sensorineural hearing loss.

A possible role of VEGF in osteolytic bone metastasis of hepatocellular carcinoma

The incidence of bone metastasis was around 13% in 404 patients with hepatocellular carcinoma (HCC) who underwent treatment at the National Kyushu Cancer Center between 1988-97, which is a high value among various cancers. This is, in part, due to the prolonged survival time of HCC patients in recent years. Serum vascular endothelial growth factor (VEGF) levels were significantly elevated in HCC patients with bone metastases as compared to those in patients with liver cirrhosis/chronic hepatitis and HCC patients without bone metastasis. VEGF was positively stained in both the primary lesion and bone metastasis of HCC by immunohistochemistry. In the process of bone metastasis, an increase in bone resorption is a crucial step prior to invasion of the bone. VEGF, the most important angiogenic factor, has been shown to stimulate bone resorption through its effects on osteoclasts. Thus, HCC cells reach the bone marrow space, and then secrete VEGF which facilitates osteolytic bone metastasis. VEGF may also facilitate tumor growth in the bone by acting as an angiogenic factor once invasion of the bone is complete. This might be another reason for the high incidence of bone metastasis in HCC.

Anti-fibrin antibody binding in valvular vegetations and kidney lesions during experimental endocarditis

In Streptococcus sanguinis (sanguis) induced experimental endocarditis, we sought evidence that the development of aortic valvular vegetation depends on the availability of fibrin. Endocarditis was induced in New Zealand white rabbits by catheter placement into the left ventricle and inoculation of the bacteria. Fibrin was localized in the developing vegetation with 99mTechnetium (Tc)-labeled anti-fibrin antibody one or three days later. When rabbit anti-fibrin antibody was given intravenously on day 1, the mass of aortic valvular vegetation was significantly reduced at day 3; infusion of non-specific rabbit IgG showed no effect. The 99mTc-labeled anti-fibrin antibody also labeled kidneys that showed macroscopic subcapsular hemorrhage. To learn if the deposition of fibrin in the kidneys was a consequence of endocarditis required a comparison of farm-bred and specific pathogen-free rabbits before and after the induction of endocarditis. Before induction, the kidneys of farm-bred rabbits were labeled, but specific pathogen-free rabbits were free of labeling and signs of macroscopic hemorrhage. After 3 days of endocarditis, kidneys of 10 of 14 specific pathogen-free rabbits labeled with 99mTc-labeled anti-fibrin antibody and showed hemorrhage. Kidney lesions were suggested to be a frequent sequellae of S. sanguinis infective endocarditis. For the first time, fibrin was shown to be required for the continued development of aortic valvular vegetations.

Flow cytometric analysis of platelet activation under calcium ion-chelating conditions

Platelet activation and aggregation results in factitious counting and sizing in routine haematology testing. In this study, the possibility of platelet activation in anticoagulated solutions was examined. Whole blood was examined using an automated counter and a flow cytometer before and after strong vortex agitation. Blood treated with ethylenediaminetetraacetic acid (EDTA) exhibited platelet activation both pre- and postagitation but activated platelets did not cause platelet aggregation. With sodium citrate, platelets were only minimally activated both pre- and postagitation. Heparin-treated blood exhibited minimal platelet activation preagitation, but agitation resulted in strong platelet activation and aggregation. Platelet size was increased by agitation in blood with EDTA and with sodium citrate, in association with significant increases in mean platelet volume (MPV) and platelet distribution width (PDW), but MPV and PDW were significantly higher in EDTA solution than in sodium citrate solution. Change in platelet size was observed even in the presence of EDTA, indicating that careful sampling and processing are needed in the collection of specimens. Specimens obtained from patients with EDTA-dependent pseudothrombocytopenia exhibited the same level of activation as controls, although platelets exhibited aggregation in such specimens. In conclusion, platelet activation involving platelet size change can occur in the absence of calcium ions in blood treated with EDTA.

Association of a G994 --> T (Val279 --> Phe) polymorphism of the plasma platelet-activating factor acetylhydrolase gene with myocardial damage in Japanese patients with nonfamilial hypertrophic cardiomyopathy

Plasma platelet-activating factor acetylhydrolase (PAF-AH) acts as a key defense against oxidative stress by hydrolyzing PAF and oxidized phospholipids. Deficiency of the activity of this enzyme may thus potentially result in predisposition to myocardial damage. The possible role of the G994 (V allele) --> T (F allele) polymorphism of the PAF-AH gene in modulating cardiac function was investigated in 142 Japanese subjects with nonfamilial hypertrophic cardiomyopathy (HCM). Logistic regression analysis adjusted for age, sex, height, and body weight revealed that the frequency of the F allele was significantly higher in HCM patients than in 284 healthy controls. Echocardiographic examination revealed that left ventricular (LV) end-diastolic and end-systolic dimensions were significantly greater in HCM patients with the FF genotype than in those with the VV genotype. Cardiac catheterization revealed that LV end-diastolic pressure was significantly higher, whereas the LV ejection fraction was significantly smaller, for HCM patients with the F allele than for those with the VV genotype. Interstitial fibrosis was significantly more severe in HCM subjects with the FF genotype than in those with the VV genotype. These results suggest that the G994 --> T (Val279 --> Phe) polymorphism in the plasma PAF-AH gene may exacerbate cardiac damage in Japanese individuals with nonfamilial HCM, although this polymorphism is unlikely to be a causative factor for this condition.

Evaluation of left ventricular function using electrocardiographically gated myocardial SPECT with (123)I-labeled fatty acid analog

Electrocardiographically (ECG) gated myocardial SPECT with (99m)Tc-tetrofosmin has been used widely to assess left ventricular (LV) function. However, the accuracy of variables using ECG gated myocardial SPECT with beta-methyl-p-(123)I-iodophenylpentadecanoic acid (BMIPP) has not been well defined.

METHODS

Thirty-six patients (29 men, 7 women; mean age, 61.6 +/- 15.6 y) with ischemic heart disease underwent ECG gated myocardial SPECT with (123)I-BMIPP and with (99m)Tc-tetrofosmin and left ventriculography (LVG) within 1 wk. LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), and LV end-systolic volume (LVESV) were determined on gated SPECT using commercially available software for automatic data analysis. These volume-related items on LVG were calculated with an area-length method and were estimated by 2 independent observers to evaluate interobserver validity. The regional wall motion with these methods was assessed visually.

RESULTS

LVEF was 41.1% +/- 12.5% on gated SPECT with (123)I-BMIPP, 44.5% +/- 13.1% on gated SPECT with (99m)Tc-tetrofosmin, and 46.0% +/- 12.7% on LVG. Global LV function and regional wall motion between both gated SPECT procedures had excellent correlation (LVEF, r = 0.943; LVEDV, r = 0.934; LVESV, r = 0.952; regional wall motion, kappa = 0.92). However, the correlations of global LV function and regional wall motion between each gated SPECT and LVG were significantly lower. Gated SPECT with (123)I-BMIPP showed the same interobserver validity as gated SPECT with (99m)Tc-tetrofosmin.

CONCLUSION

Gated SPECT with (123)I-BMIPP provides high accuracy with regard to LV function and is sufficiently applicable for use in clinical SPECT. This technique can simultaneously reveal myocardial fatty acid metabolism and LV function, which may be useful to evaluate various cardiac diseases.

Birth of healthy twins from in vitro development of human refrozen embryos

OBJECTIVE

To avoid the risk of ovarian hyperstimulation syndrome and promote pregnancy rate by freezing pronuclear embryos at the oocyte retrieval and using developed refrozen supernumerary embryos in the event of failed pregnancies.

DESIGN

A case study.

SETTING

Private IVF center.

PATIENT(S)

Healthy infertile woman undergoing IVF treatment.

INTERVENTION(S)

Slowly frozen and rapidly refrozen embryos at varying stages of embryonic development were transferred.

MAIN OUTCOME MEASURE(S)

Survival rate of refrozen and thawed embryos; safety of refrozen embryo transference.

RESULT(S)

Fertilized pronuclear embryos that were frozen, thawed, and developed to morula embryos were subsequently vitrified, rethawed, and cultured until blastocyst formation before transfer. Healthy fraternal twins were born by caesarian section. The result of transfer was the novel finding of a successful delivery after the use of refrozen embryos.

CONCLUSION(S)

The transfer of refrozen supernumerary embryos resulted in successful pregnancy and delivery. We will continue to investigate the safety and efficacy of the elective freezing of all embryos as well as their refreezing so that supernumerary embryos can be reused to avoid ovarian hyperstimulation syndrome or in cases of repeated failed pregnancies.

Surgical repair of double-orifice of the mitral valve in cases with an atrioventricular canal defects

OBJECTIVE

A Double-orifice in the mitral valve is an uncommon congenital cardiac lesion which occurs as an isolated anomaly or in association with other cardiac malformation. This report deals with our surgical experience of a double-orifice of the mitral valve in cases with an atrioventricular canal defect.

PATIENTS AND METHODS

From 1991 through 1999, ten patients were diagnosed to have a double-orifice of the mitral valve at Shizuoka Children's Hospital. Each patient had associated major cardiac malformations, among which atrioventricular canal defect underwent surgical management, with five of these undergoing complete correction with or without previous pulmonary artery banding. Of these 10, the five cases were enrolled in this study. Two of these had a complete type, and the other three had a partial type. The cleft in the left-sided atrioventricular valve was closed partially in four and left untouched in one. Bridging tissue, when present, was left intact. There was no regurgitation from any accessory orifice and no repair for an accessory orifice was needed.

RESULT

There was no late death and no replacement of the valve with prosthesis. During follow-up ranging from 1 to 4 years, none of the patients developed severe stenosis or progressive regurgitation in the left-sided atrioventricular valve.

CONCLUSION

Meticulous surgical management of a double-orifice in the mitral valve in association with atrioventricular canal defect an achieve an acceptable midterm result without developing severe dysfunction in the left-sided atrioventricular valve.

Measurement of flecainide in hair as an index of drug exposure

We report a method for measuring the concentration of flecainide in hair. An animal study, in which flecainide (1, 5, and 10 mg/kg/day) was orally administered for 1, 2, and 3 weeks to pigmented rats, showed that flecainide concentration in rat hairs newly regrown after administration significantly correlated with both the daily dose and the dosing period. The part of hair containing flecainide continued to grow upward, retaining the drug within the hair structure that had been formed at the time of drug exposure. Flecainide was also determined in human scalp hairs collected from patients treated with flecainide. The drug content of white hairs was much less than that black hairs collected from the same rats and subjects, suggesting the determinant effect of hair pigment on flecainide accumulation in hair. These findings suggest that the analysis of flecainide in hair may be useful for assessing exposure to drug qualitatively.

Mild to severe lithium-induced nephropathy models and urine N-acetyl-beta-D-glucosaminidase in rats

Long-term treatment with lithium induces functional and/or structural disturbances in the kidneys. However, no procedure has been established for the early diagnosis of lithium intoxication. In this study, we prepared mild to severe lithium-induced nephropathy rat models and examined the usefulness of urine N-acetyl-beta-D-glucosaminidase (NAG) for the early diagnosis of lithium-induced renal insufficiency. Lithium was administered by repeated intraperitoneal injection (1, 2 and 4 mEq/kg/day for 10 days). We also measured the plasma creatinine and paraaminohippuric acid (PAH) clearance, and observed renal histological changes. Lithium pretreatment elevated the plasma creatinine level and decreased PAH clearance in a dose-dependent manner. The NAG level in the lithium 4 mEq/kg group was very high. The levels in the lithium 1 mEq/kg and 2 mEq/kg groups were almost the same and were higher than the control group. A histological examination of the kidney revealed glomerular congestion and/or atrophy and tubular expansion in all of the groups except the control group. These histological changes were dose-dependent. In conclusion, urine NAG may be useful in the early diagnosis of renal side effects caused by lithium therapy. When the urine NAG level becomes high in a patient taking lithium for bipolar disorder, the physician may need to consider lithium-induced renal insufficiency.

Stabilized phase-shifting fringe analysis by use of current-induced frequency modulation of laser diodes

A closed-loop phase-shifting Fizeau-type interferometer was constructed that uses direct frequency modulation of a laser diode. The interferometer is servo controlled entirely in the phase domain, where optical phases are detected by two-frequency optical heterodyning. A detailed study of stabilization of the interferometer under feedback control was conducted both experimentally and theoretically. The interferometer showed good stability against vibration up to 200 Hz. The stabilization factors obtained experimentally are in good agreement with the theoretical calculations. The phase-shifting experiment was accomplished with high precision as well as with high stability against external disturbances. The profile measurement of a mirror surface was made with a phase-shifting analysis algorithm, and good measurement reproducibility of lambda/60 in the root-mean-square value was obtained for ten measurements within a period of 20 min.

Increased incidence of bone metastases in hepatocellular carcinoma

OBJECTIVES

Recently, we often encounter hepatocellular carcinoma patients with bone metastases. We therefore examined the changes in the incidence of bone metastases in hepatocellular carcinoma from 1978 to 1997 and tried to identify the characteristic clinical features. We also discuss the reasons for the increased incidence of bone metastasis in hepatocellular carcinoma.

METHODS

A total of 673 patients with hepatocellular carcinoma during the period 1978-1997 were studied. Bone metastasis was screened by bone scintigraphy, and bone lesions were confirmed by plain radiography, computed tomography and/or magnetic resonance imaging. The serum levels of the C-terminal telopeptide of type 1 collagen, which represent osteoclastic bone resorption, were also measured.

RESULTS

The incidence of bone metastasis during the decade 1988-1997 was significantly higher than that during the period 1978-1987. The median survival time of patients with hepatocellular carcinoma during 1988-1997 was also significantly longer than that during 1978-1987. Portal thrombus was found in about half of the patients with bone metastases. The most common site of bone metastases was the vertebra followed by the pelvis, rib and skull in that order. All bone lesions depicted by plain radiograph, computed tomography and/or magnetic resonance imaging were of the osteolytic type, and the serum levels of C-terminal telopeptide of type 1 collagen were significantly elevated in the patients with bone metastases.

CONCLUSIONS

The increased incidence of bone metastasis in hepatocellular carcinoma in the decade 1988-1997 is first attributed to the prolonged survival rate of hepatocellular carcinoma patients due to recent progress in both the diagnosis and treatment of the disease. Dissemination of hepatocellular carcinoma cells to the vertebra through the portal vein-vertebral vein plexuses due to the presence of portal thrombus and/or portal hypertension may be related to a higher incidence of bone metastasis in hepatocellular carcinoma. Both an early diagnosis and timely treatment of bone metastases are thus called for in the follow-up of hepatocellular carcinoma patients.

[Association of polymorphisms of the transforming growth factor-beta 1 gene with genetic susceptibility to osteoporosis]

Osteoporosis exhibits a substantial genetic component. Although polymorphisms of a variety of genes have been associated with bone mineral density and genetic susceptibility to osteoporosis, the genes responsible for these traits have not been definitively identified. We have shown that a T869-->C polymorphism of the transforming growth factor-beta 1 gene, which results in a Leu-->Pro substitution at amino acid 10, is associated with bone mineral density in Japanese adolescents and postmenopausal women, with genetic susceptibility to both osteoporosis and vertebral fracture, and with the outcome of treatment for osteoporosis with active vitamin D. We have also shown that a C-509-->T polymorphism in the promoter region of this gene is associated with both bone mineral density and the prevalence of osteoporosis in postmenopausal women. In addition, analysis of combined genotypes for both the C-509-->T and T869-->C polymorphisms revealed that bone mineral density decreases and the susceptibility to osteoporosis increases with the number of T alleles. Thus, combined genotyping of the C-509-->T and T869-->C polymorphisms may prove beneficial in the prevention of osteoporosis in postmenopausal Japanese women. I here review the association of transforming growth factor-beta 1 gene polymorphisms with genetic susceptibility to osteoporosis, which has provided insight into the function of transforming growth factor-beta 1 as well as into the role of genetic factors in the development of osteoporosis.

Evaluation of prostate-specific antigen (PSA) membrane test for forensic examination of semen

Prostate-specific antigen (PSA) is a glycoprotein produced by the prostatic gland and functions to liquefy the seminal fluid. Recently several PSA membrane test kits utilizing an immunochromatographic assay are commercially available for clinical screening of PSA concentration in serum. In this study, we applied the three PSA test kits to forensic examination of semen, and evaluated the sensitivity and specificity of the PSA test kits. The specificity were the same, but SMITEST PSA Card had the highest sensitivity among the three kits. Furthermore we certified that the SMITEST PSA Card was little affected by heat or contaminants such as other body fluids, reagent of preliminary test for semen stain and spermicides, and the PSA kit was applied to 30 casework samples.

Reduced myocardial sarcoplasmic reticulum Ca(2+)-ATPase mRNA expression and biphasic force-frequency relations in patients with hypertrophic cardiomyopathy

BACKGROUND

The relationship between left ventricular (LV) contractile functional reserve and gene expression of Ca(2+)-handling proteins in patients with hypertrophic cardiomyopathy (HCM) remains to be clarified.

METHODS AND RESULTS

We calculated the maximum first derivative of LV pressure (LV dP/dt(max)) and the LV pressure half-time (T(1/2)) during pacing in 14 patients with nonobstructive HCM (LV ejection fraction >55%) and 7 control subjects. Endomyocardial tissue was obtained, and mRNA levels of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2), ryanodine receptor-2, phospholamban, calsequestrin, and Na(+)/Ca(2+) exchanger were quantified by use of a real-time quantitative reverse transcription-polymerase chain reaction method. Group A consisted of 7 HCM patients who showed a progressive rise in the LV dP/dt(max) with increased heart rate. Group B consisted of 7 HCM patients in whom the heart rate-LV dP/dt(max) relation was biphasic at physiological pacing rates. Both the mean maximal wall thickness and the LV hypertrophy score in group B were greater than in group A (20+/-5 versus 15+/-3 mm and 7+/-1 versus 5+/-2 points, respectively). SERCA2 mRNA levels were significantly lower in group B (SERCA2/GAPDH ratio 0.34+/-0.15) compared with group A (0.72+/-0.27) and control subjects (0.85+/-0.47), whereas the mRNA expression of ryanodine receptor-2, phospholamban, calsequestrin, and Na(+)/Ca(2+) exchanger were similar in all groups.

CONCLUSIONS

These results suggest that downregulation of SERCA2 mRNA, resulting in altered Ca(2+) handling, may contribute to impaired LV contractile reserve in HCM patients with severe hypertrophy, even in the absence of detectable baseline systolic dysfunction.