[Posterior interosseous nerve paralysis caused by ganglion: a case report]

A 63-year-old man presented with a posterior interosseous nerve palsy secondary to a ganglion compressing the nerve against the arcade of Frohse. Decompression and neurolysis resulted in full functional recovery. While patients with the so-called classic "Saturday night palsy" or even patients with a radial nerve palsy secondary to a fractured humerus may be expected to recover completely without surgery, early surgery is the conservative approach in patients with a nerve palsy secondary to the mass. However it is difficult to diagnose the nerve palsy secondary to the small mass. The treatment for patients with a progressive nerve palsy of unknown origin must be given attention.

Hypotensive action of taurine in DOCA-salt rats--involvement of sympathoadrenal inhibition and endogenous opiate

We studied the roles of the sympathoadrenal system and endogenous opiate in the antihypertensive effects of supplementation of dietary taurine, a sulfur amino acid, in deoxycorticosterone acetate (DOCA)-salt rats. Supplementation of 1% taurine in drinking water for 2 weeks was found to prevent the increase in systolic blood pressure of DOCA-salt rats (116 +/- 2 vs 138 +/- 2 mmHg, p less than 0.01), but failed to effect the systolic blood pressure of vehicle-treated control rats (115 +/- 2 vs 112 +/- 3 mmHg), taurine supplementation restored to normal increased plasma norepinephrine (326 +/- 32 vs 531 +/- 67 pg/ml, p less than 0.01) and epinephrine (204 +/- 19 vs 304 +/- 43 pg/ml, p less than 0.05) concentrations in DOCA-salt rats, but had no effect on norepinephrine (346 +/- 23 vs 338 +/- 33 pg/ml) or epinephrine (198 +/- 17 vs 224 +/- 26 pg/ml) concentrations in control rats. Accordingly, the increased epinephrine content in the adrenals of DOCA-salt rats was normalized with the supplementation of taurine, associated with a markedly increased adrenal taurine content. In conscious rats, moreover, intraperitoneal injection of naloxone (2 mg/kg), a specific opiate antagonist, increased systolic blood pressure only in taurine-supplemented DOCA-salt rats. Evidence presented suggests, therefore, that both the suppression of the increased sympathoadrenal activity and the activation of endogenous opiate might contribute to the antihypertensive effect of taurine in DOCA-salt rats.

Taste cells in the gut and on the tongue. Their common, paraneuronal features

Chemoreception of foodstuff in the gut is performed by endocrine cells dispersed in the gut epithelium. They are bipolar cells extending an apical process to the gut lumen and releasing their messenger substances from the cell base in response to the apical stimuli. The cells share cell-biological features with neurons and are classified as paraneurons. Noteworthy, the gut paraneurons do not seem to be stimulated by monosodium glutamate (MSG) as our dog experiment indicates. Administration of 50 mM MSG into the duodenal loop of anesthetized dogs did not cause changes in the volume and protein output in the pancreatic juice. The gustatory cells in the taste bud show essentially the same structure and function as the gut endocrine cells. A single gustatory cell type (type III) seems to receive different chemical stimuli, whereas different endocrine cell types in the gut react to different stimuli. The gustatory cells possess numerous peptidergic-type granules besides synapse-associated small clear vesicles. The former granules, in the guinea pig and dog, are abundant in the cytoplasm, giving an endocrine-like appearance to the cell. Peptidic signal substances contained in the granules remain to be identified. Comparison of the gustatory cells in the taste bud with the endocrine cells in the gut and with other paraneurons may put into front certain hitherto unexplored structures and functions of the cells.

Response of the taste receptor cell to the umami-substance stimulus. An electron-microscopic study

The chemosensory gustatory cells in taste buds form chemical synapses with intragemmal neurites. We investigated the ultrastructure of the guinea pig gustatory cells after stimulation with a mixture of monosodium L-glutamate and guanosine 5'-monophosphate. The gustatory cells responded to the stimulus. The dense-cored vesicles localized in the presynaptic regions discharged the contents into the synaptic cleft by means of exocytosis, which resulted in a marked decrease of their population. These findings strongly suggest that the transmitter or transmitters contained in the vesicles are released in response to the taste stimulation at the cell apex, to conduct the excitement of the cell to the nerves.

[Trends in length of stay of psychiatric inpatients based on "patient survey"]

The average length of occupancy for psychiatric beds in Japan has been pointed out to be among the longest in the world. However, neither the average length of occupancy since admission of psychiatric resident patients present at a facility at a given point of time (e.g. at the end of every October) nor the average length of stay of psychiatric patients until discharge have been reported in national health statistics. Using data from the "Patient Survey (1974-1984, 1987)" by the Ministry of Health and Welfare, estimates of trends for 1) length of hospitalization since admission of resident patients at the end of every October and 2) length of hospital stay from admission to discharge in patient cohorts admitted each year from 1974 to 1984, were determined. A remarkable difference in distribution was observed in the length of hospitalization in psychiatric residents and length of stay until discharge. For psychiatric residents surveyed at the end of October 1987, 13% had been resident for less than 3 months, 27% within one year, and 54% within 5 years. On the other hand, 33% of the patient cohort admitted in 1984 were discharged within one month, 59% within 3 months, and 85% within one year. Six percent of the cohort, however, had remained hospitalized for more than 3 years, some of whom were potential 'new' long-stay patients. The proportion of patients staying more than ten years shows an increase from 17% in 1974 to 30% in 1987, with the distribution of length of hospitalization in residents demonstrating a definite shift to increased length. On the other hand, length of stay until discharge shows a slight shortening.

High potassium intake attenuates antinatriuretic response to air stress in DOCA-salt rats

We studied the effects of potassium supplementation (2 wk of 0.5% KCl to drink) on responses of renal function to a stressful environmental stimulus (air stress) in deoxycorticosterone acetate (DOCA)-salt rats. In conscious DOCA-salt rats, air stress decreased urine flow rate and urinary sodium excretion without changes in effective renal plasma flow and glomerular filtration rate, whereas in normotensive vehicle-treated rats air stress had no effect on these measures. Renal denervation abolished the antidiuretic and antinatriuretic responses to air stress in DOCA-salt rats. Correspondingly potassium supplementation in DOCA-salt rats could not only reduce basal blood pressure significantly but also attenuate the antidiuretic and antinatriuretic responses to air stress without renal denervation. Evidence suggests that the attenuation by potassium supplementation of air stress-induced decrease in urine flow and sodium excretion in DOCA-salt rats may be partly involved in the natriuretic and the resultant antihypertensive actions of potassium in DOCA-salt hypertensive rats, but the mechanisms could not be clarified by the present study.

Stimulation of prostaglandin synthesis in rabbit gastric antral mucosal slices by desferrioxamine in vitro

Desferrioxamine is an iron-chelating agent used in the treatment of iron overload. It is a powerful inhibitor of iron-dependent radical reactions. The effect of desferrioxamine of prostaglandin (PG) synthesis and metabolism in rabbit gastric antral mucosal slices has been examined. Desferrioxamine significantly enhanced the production of PGE2 and PGF2 alpha. The formation of 13,14-dihydro-15-keto PGE2 and 13,14-dihydro-15-keto PGF2 alpha was also increased slightly by desferrioxamine. The addition of Fe3+ or Al3+ blocked the stimulatory action of desferrioxamine on PGE2 and PGF2 alpha production. Desferrioxamine appears to be stimulating the activity of PG cyclooxygenase through the removal of endogenous antral mucosal iron. These results suggest that desferrioxamine has the potential to increase the PG levels in gastric mucosa by primarily stimulating PG biosynthesis. The possibility that desferrioxamine may be of therapeutic value in the treatment of ischemic injury in the stomach is discussed.

Phorbol ester induces desensitization of PTH-stimulated cyclic AMP production by decreasing the PTH receptor binding in UMR-106 cells

Pretreatment of UMR-106 cells (rat osteoblast like osteosarcoma cell line) with the protein kinase C(PK-C) activating phorbol ester, phorbol 12-myristate 13-acetate (PMA) results in a time dependent (1-12h) desensitization of PTH-stimulated cAMP production. Compared to controls, PMA-treated cells showed 50% decrease of PTH-stimulated cAMP production. PK-C inhibitor, H-7 significantly blocked this PMA-induced desensitization. PTH receptor binding, assessed with 125I-[Nle8,Nle18,Tyr34]PTH-(1-34) as radioligand, was decreased by about 20% in PMA-treated cells. H-7 treatment completely restored receptor binding in PMA-treated cells. These data suggest that PK-C might act directly on PTH receptor which is coupling to adenylate cyclase, and induce desensitization.

Inhibition of cellular proliferation in human T lyophotropic virus type I (HTLV-I)-infected T cells from patients with HAM by steroid hormones and cyclosporin A

The effects of steroid hormones and Cyclosporin A (CsA) on de novo DNA synthesis in four human T lymphotropic virus type I (HTLV-I)-infected T cell lines from patients with HTLV-I-associated myelopathy (HAM) were investigated. These T cell lines were characterized by helper/inducer phenotypes and expressed IL-2-receptor (Tac) and HLA-DR antigen in high percentages. Three of the four cell lines had their de novo DNA synthesis inhibited by steroid hormones (dexamethasone and 1,25-dihydroxyvitamin D3 (1,25 (OH)2D3)) and CsA in a dose dependent manner. The inhibitory effects arose 24 hours after initiation of incubation with either steroid hormones or CsA. The forth cell line was not inhibited by these reagents. It also revealed through the use of an in vitro assay utilizing the human IL-2 dependent cell line, Sez 627, that none of these T cell lines secrete IL-2 in detectable volumes. In order to clarify the mechanism of the inhibitory effects of steroid hormones and CsA, among these 4 cell lines H-89-59, insensitive to the reagents, and H-109, sensitive to them, were used for northern blotting analysis. C-myc gene expression was demonstrated both in H-89-59 and H-109. 1,25(OH)2D3 and CsA suppressed c-myc expression in H-109 as well as cell proliferation. In H-89-59, however, neither expression of c-myc nor cell proliferation was suppressed. On the other hand, the level of HTLV-I gene transcripts was not changed by these agents. Hence, inhibition of cellular proliferation by these reagents was not caused by the inhibition of HTLV-I p40(x) gene but by inhibition of transcriptional factors such as c-myc products.

Assessment of hypertensive heart by 2-dimensional echocardiography in mass screening

Two-dimensional echocardiography (2DE) was used in the mass screening of 3,017 participants (1,195 males, 1,822 females, mean age 59) living in 13 areas in Japan. The 2DE findings of left ventricular hypertrophy (LVH) and LV function were compared with the presence and severity of hypertension (Ht). Out of 1,100 patients who had an evident history of Ht above 160/95 mmHg (Ht group), 298 patients (27.4%) were complicated by LVH. In contrast, LVH was also recognized in 60 (11.2%) of 535 borderline Ht cases and in 87 (6.3%) of 1,382 normotension cases. LVH cases in the Ht group were divided into 3 groups: mild (220: 73.8%), moderate (63: 21.2) and severe (15: 5.0). Asymmetric septal hypertrophy (ASH) was recognized in 111 patients (37.2%) of the 298 LVH cases. The prevalence of ASH in these LVH patients was higher according to the severity of the LVH: mild LVH = 31%, moderate LVH = 51% and severe LVH = 67%. The prevalence of LVH was higher in males than in females. This was especially apparent in the moderate to severe LVH groups and also noted to be higher according to the increase of mean blood pressure. The prevalence of mild to moderate LVH was significantly higher in the poorly-controlled group than in the well-controlled group. In contrast, no significant difference in prevalence of severe LVH was noted between the well-controlled and poorly-controlled groups. The prevalence of LV dysfunction was significantly greater in moderate or severe LVH groups than in non or mild LVH groups. It tended to be higher in the poorly-controlled group compared with the well-controlled group. The regression of LVH was frequently detected in the well-controlled group by the follow-up study. We conclude that 2DE observation of LV performance in mass screening will be extremely valuable in the long term follow-up of Ht patients.

Role of endogenous endothelin in the development of hypertension in rats

To further elucidate the pathophysiologic role of endogenous endothelin (ET), we have studied the chronic effect of anti-ET gamma-globulin on the development of hypertension in spontaneously hypertensive rats (SHR) and stroke prone SHR (SHR-SP) for three weeks. In neither SHR nor SHR-SP did repetitive bolus injection of anti-ET gamma-globulin suppress the rise in blood pressure. The present data suggest that endogenous ET is not likely to play a key role in the development of hypertension, although ET may induce a local vasoconstriction at the injured vascular wall.

Triacylglycerol lipase mediated release of arachidonic acid for prostaglandin synthesis in rabbit kidney medulla microsomes

The effect of triarachidonin on the synthesis of prostaglandins in rabbit kidney medulla microsomes was examined. Medulla microsomes were incubated with triarachidonin in 0.1 M--Tris/HCl buffer (pH 7.0) containing reduced glutathione and hydroquinone and the formed prostaglandin E2, prostaglandin F2 alpha and prostaglandin D2 were measured by high-pressure liquid chromatography using 9-anthryldiazomethane for derivatization. The addition of triarachidonin (1-10 microM) stimulated prostaglandin formation in a dose-dependent manner. Under our incubation conditions rabbit kidney medulla was found to produce prostaglandin E2 mainly. When arachidonic acid, instead of triarachidonin, was added to the incubation mixture of microsomes, the identical profile of prostaglandin products was obtained. When the pH of the reaction mixture was changed from 7.0 to 8.0, the rate of triarachidonin-induced prostaglandin E2 formation was approximately 60% of that observed at pH 7.0. Studies utilizing Ca2+ and EGTA revealed that triacylglycerol lipase of kidney medulla is independent of Ca2+. The addition of epinephrine made the stimulatory effect of triarachidonin on prostaglandin E2 formation more pronounced. These results suggest that epinephrine-activated triacylglycerol lipase is present in the renomedullary microsomes, and this enzyme activity is a potential mediator of release of arachidonic acid for prostaglandin synthesis in the kidney medulla.

Platelet-derived growth factor B chain homodimer enhances chemotaxis and DNA synthesis in normal osteoblast-like cells (MC3T3-E1)

We demonstrate that recombinant platelet-derived growth factor B chain homodimer (PDGF-BB) could induce both the chemotactic activity and the DNA synthesis in a normal osteoblast-like cell line (MC3T3-E1). Cell migration toward recombinant human PDGF-BB was observed with the modified Boyden chamber technique. Maximum chemotaxis was exhibited at 25 ng/ml of PDGF-BB. DNA synthesis as indicated by [3H]-thymidine incorporation was also enhanced about 4-fold at 25-100 ng/ml PDGF-BB. Our results suggested that PDGF might be one of the candidates among local coupling factors for bone remodeling.

Comparison of the in vivo anticoagulant properties of standard heparin and the highly selective factor Xa inhibitors antistasin and tick anticoagulant peptide (TAP) in a rabbit model of venous thrombosis

An in vivo thromboplastin (TP)-induced venous stasis thrombosis model in rabbits was used to compare the efficacy of standard heparin with the selective factor Xa inhibitors, recombinant tick anticoagulant peptide (rTAP) and recombinant antistasin (rATS), in prophylactic prevention of thrombus formation. Heparin significantly reduced TP-induced clot formation at doses of 55 and 100 U kg-1h-1 yielding clot weights of 9 +/- 4 and 6 +/- 2%, respectively. Clot formation was significantly decreased by i.v. infusions of rTAP at doses of 21, 37 and 64 micrograms kg-1 min-1 resulting in normalized clot weights of 13 +/- 3, 8 +/- 2 and 2 +/- 1%, respectively. rATS was approximately 10-fold more potent than rTAP, reducing normalized clot weights to 16 +/- 5, 2 +/- 1 and 1 +/- 0.8% at rATS doses of 1.25, 2.5 and 5.0 micrograms kg-1 min-1, respectively. These data suggest that factor Xa-mediated inhibition of coagulation with rTAP and rATS is as effective as conventional anticoagulant treatment with heparin in preventing venous thrombosis.

Effect of salt loading on aldosterone response to long-term infusion of angiotensin II in rats

We examined changes in plasma aldosterone level and blood pressure (BP) after long-term (12 days) intravenous infusion of angiotensin II (Ang II; 15 and 60 ng/min) with two different sodium intakes (0.66% and 8% salt-containing diet) in Wistar rats. Without salt loading, 15 ng/min of Ang II did not increase mean BP (112 +/- 1 vs. 112 +/- 2 mm Hg), but 60 ng/min of Ang II increased mean BP (144 +/- 3 mm Hg, p less than 0.01). However, the 8% salt diet not only enhanced the pressor effect of 60 ng/min Ang II (168 +/- 9 mm Hg, p less than 0.05), but also elevated mean BP with 15 ng/min of Ang II (159 +/- 3 mm Hg, p less than 0.01). On a normal-salt diet (0.66%), plasma aldosterone was increased by Ang II infusion from 11.3 +/- 0.3 ng/dl to 12.7 +/- 0.5 ng/dl (NS) at a rate of 15 ng/min Ang II, and to 15.7 +/- 0.4 ng/dl (p less than 0.01) at 60 ng/min Ang II. However, salt loading reduced Ang II-induced elevation of aldosterone: 11.3 +/- 0.5 ng/dl (less than 0.01) at a rate of 60 ng/min Ang II. Thus, salt loading diminished aldosterone response to Ang II, which might compensate salt-induced enhancement of the pressor effect of Ang II.

Effects of continuous infusion of parathyroid hormone and parathyroid hormone-related peptide on rat bone in vivo: comparative study by histomorphometry

We have investigated the actions of parathyroid hormone (PTH) and PTH-related peptide (PTHrP) on the bones of parathyroidectomized (PTX) rats by histomorphometric analysis. Miniosmotic pumps filled with either human PTH (hPTH)(1-34), hPTHrP(1-34) or vehicle were subcutaneously implanted on the backs of the rats. The peptides were continuously infused for 6 days at a rate of 15 nmole/kg/day. PTH and PTHrP exhibited similar hypercalcemic and hypophosphatemic actions on these PTX rats. No significant differences were noted in bone weight or calcium and phosphorus contents of the ashed bone among the 3 groups. By quantitative histomorphometric analysis, hPTH(1-34) and hPTHrP(1-34) were found similarly to enhance both bone formation and resorption. Peritrabecular fibrosis was observed only in the PTH-infused animals. PTHrP thus mimics the actions of PTH, but is not as effective in promoting mesenchymal cell proliferation along the bone trabeculae.

Expression of decay-accelerating factor is reduced on hyperplastic synovial lining cells in rheumatoid synovitis

Decay-accelerating factor (DAF), a membrane inhibitor of homologous complement activation, is present in synovial cells lining joint space and detected in synovial fluid. DAF is considered to protect synovial membrane from complement-mediated injury associated with articular inflammation. We studied the immunohistopathological features of DAF molecules in synovial membrane of rheumatoid synovitis using a DAF-specific monoclonal antibody, 1C6. Reacting molecules with the 1C6 antibodies in synovial tissue extracts formed a 70-kD band in Western blot analysis. DAF was strongly detected on the flat synovial lining cells, but weakly on the hyperplastic and multi-layered lining cells in rheumatoid synovitis. The latter cells reacted with anti-Leu-M3 antibodies specific for a cell surface marker of activated macrophages, sometimes accompanied by C3 and IgM deposition on the superficial synovial membrane. These results suggest that active rheumatoid synovitis characteristically with hyperplastic synovial lining cells is out of control by DAF, thereby permitting further complement-mediated injury.

The effects of several pharmacologic agents upon postischemic recovery

Using an isolated working rat heart model, the effects of DL-verapamil, ryanodine, gabexate mesilate (FOY), recombinant human superoxide dismutase (RH-SOD), and coenzyme Q10 upon myocardial protection were evaluated. Under conditions of normothermic ischemia, all these compounds, except RH-SOD, when added to the St. Thomas' cardioplegic solution at an optimal concentration, showed beneficial effects upon functional recovery and enzyme leakage. In contrast, the above compounds, except ryanodine and FOY, failed to improve the protective properties of the St. Thomas' cardioplegic solution under conditions of hypothermic ischemia. Our results indicate that calcium overload via the calcium channel and calcium-induced calcium release from sarcoplasmic reticulum (SR) may contribute to the onset of ischemic-reperfusion injury. However, under conditions of hypothermic ischemia, calcium-induced calcium release from SR plays a dominant role in calcium overload. Furthermore, intracellular calcium overload may activate proteases and result in the acceleration of myocardial injury.

Fine structure of the taste bud in guinea pigs. II. Localization of spot 35 protein, a cerebellar Purkinje cell-specific protein, as revealed by electron-microscopic immunocytochemistry

The localization of spot 35 protein, a cerebellar Purkinje cell-specific protein, was studied in guinea pig taste buds by means of electron-microscopic immunocytochemistry. The immunoreactivity was localized in the cytoplasmic matrix of discrete bud cells. The ultrastructural features of the reactive cells indicated that they corresponded to the Type III or gustatory cells making a synaptic contact with the intragemmal nerves. All other cells specified as basal, Type I, and Type II were immunonegative for spot 35 protein. This finding indicates a method for specifically demonstrating the gustatory cells in the guinea pig taste bud and, further, gives new evidence that paraneurons may share neuron-specific substances with neurons.

Immunohistologic evaluation of parathyroid hormone-related protein in human lung cancer and normal tissue with newly developed monoclonal antibody

With a newly developed monoclonal anti-PTHrP antibody, 4B3, the immunohistochemical localization of the parathyroid hormone-related protein (PTHrP) was studied on the formalin-fixed and paraffin-embedded sections of normal human tissues and various subtypes of lung cancer. Among normal epithelial tissues, keratinocytes in squamous epithelia, transitional and bronchial epithelia with squamous metaplasia, meningoepithelial cells, and mammary ductal cells with lactating changes showed positive immunoreactivity. Also, among endocrine tissues, cells in the parathyroid gland, pancreatic islets, adrenal cortex, pituitary gland, and testis were sporadically positive for PTHrP. These distribution patterns suggested that in a physiologic condition, PTHrP was closely related to keratinization and local secretion and/or the metabolism of calcium in specifically differentiated tissues. In lung cancer, however, PTHrP was detected in all cases of well-differentiated and moderately differentiated squamous cell carcinoma and in most cases of small cell carcinoma, irrespective of the patients' serum calcium level. However, PTHrP was not detected in two of five cases of poorly differentiated squamous cell carcinoma and in all cases of adenocarcinoma. Consequently, it was found that PTHrP was commonly produced by squamous cell carcinomas of the differentiated type, and that humoral hypercalcemia of malignancy could be induced when the PTHrP transgressed the homeostatic mechanisms.

Potent anti-angiogenic action of AGM-1470: comparison to the fumagillin parent

The anti-angiogenic activity of AGM-1470, a new synthetic analog of fumagillin isolated from Aspergillus fumigatus, was extensively examined both in vitro and in vivo using four different types of assay and compared to that of the fumagillin parent. Locally administered AGM-1470 inhibited the angiogenesis in the chick embryo chorioallantoic membrane assay and the rat corneal assay. In the rat sponge implantation assay, systemically administered AGM-1470 inhibited angiogenesis induced by basic fibroblast growth factor. Furthermore, in the rat blood vessel organ culture assay, AGM-1470 (1-1,000 ng/ml) was found to selectively inhibit the capillary-like tube formation of endothelial cells with a minimal effect on the non-endothelial cell growth. AGM-1470 showed more potent anti-angiogenic activity and less toxicity than the fumagillin parent. Therefore, AGM-1470 is much better than the fumagillin parent as anti-angiogenic compound.

Effects of injection site on the accuracy of thermal washout right ventricular ejection fraction measurements in clinical and model investigations

The purpose of this investigation was to improve the accuracy of measurement of thermal right ventricular ejection fraction (RVEF) using the modified Swan-Ganz catheter. Three serial ejection fractions (EFs) (EF1, 2, 3) and the mean were calculated, based on Holt's theory. RVEFs were compared between right ventricular (RV) and atrial (RA) injection in ten intensive care unit (ICU) patients using a modified catheter having RV and RA orifices (15 cm and 30 cm from the distal end, respectively), and paired duplicate (two patients) or triplicate (eight patients) measurements were performed. To determine what factors interfere with RVEF, a model heart (with diastolic volume of 150 ml) was constructed, in which model injection of cold water to the direct inflow tract (RA), to the direct mixing chamber (RV), or through the catheter running in the inflow tract were compared. When EFs were compared between RV and RA injection, those for the former were greater (RV vs RA in EF1 and EFmean: 0.46 +/- 0.15 vs 0.23 +/- 0.11 in EF1, and 0.45 +/- 0.13 vs 0.28 +/- 0.11 in EFmean, mean +/- SD, p less than 0.01). When the serial EFs were compared in each injection type, in the RV injection EF3 was the smallest as was EF1 in the RA injection. The same phenomenon was observed in the model as in the patients, and moreover when cold water was injected in RA through a catheter running through the circuit, EFs were greatly underestimated (EF1 = 0.29 +/- 0.02 at preset EF = 0.4). We conclude that these phenomena were caused by sluggish movement of the cold indicator from RA to RV when injected into RA, and by interference with the cooled cardiac chamber and catheter. Consequently, the first or second EFs obtained from RV injection might be closest to the actual values because of the least interference with those factors.