[Risk factors and preoperative evaluation of lymph nodes posterior to right recurrent laryngeal nerve metastasis in thyroid papillary carcinoma].

Objective: To investigate the risk factors and preoperative evaluation of lymph nodes posterior to right recurrent laryngeal nerve (LN-prRLN) metastasis in papillary thyroid carcinoma (PTC). Methods: Clinical data of 301 patients with right or double lobes who underwent surgery between August 2015 and October 2016 in the Department of Thyroid Surgery, the First Hospital of China Medical University, were retrospectively analyzed. The relationships between LN-prRLN metastasis and clinical pathology data and other factors were analyzed. The enhanced CT difference of LN-prRLN was analyzed by receiver operating characteristic (ROC) curves. Results: LN-prRLN metastasis was detected in 46 patients. Univariate analysis showed that age, tumor diameter, Delphian lymph node metastasis, lymph nodes anterior to right recurrent laryngeal nerve (LN-arRLN) metastasis number, and the number of lateral compartment lymph node metastases were significantly associated with LN-prRLN metastasis (all P<0.05). Multivariate logistic regression analysis showed that LN-arRLN metastasis and right lateral compartment lymph node metastasis were independent risk factors for LN-prRLN metastasis (both P<0.05). The area under the ROC curve for contrast-enhanced thyroid CT was 0.948 (P<0.001), the cut-off value was 72 Hu, and the best sensitivity and specificity were 90.5% and 94.1%, respectively, with a Youden index of 0.846. Conclusion: LN-prRLN dissection is recommended when there exists LN-arRLN metastasis or right lateral compartment lymph node metastasis in patients with PTC, especially when preoperative contrast-enhanced CT shows LN-prRLN and contrast-enhanced CT is ≥72 Hu.

[Effect of probucol on preventing contrast-induced nephropathy in patients undergoing percutaneous coronary intervention].

Objective: To investigate the preventive effect, possible mechanism and safety of probucol on contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI) in patients with coronary heart disease (CHD). Methods: A total of 641 patients with coronary heart disease were consecutively enrolled from Department of Cardiology, in Tianjin Chest Hospital, Tianjin TEDA International Cardiovascular Hospital, Tianjin First Central Hospital, Tianjin Fourth Central Hospital. They were randomly divided into probucol group (n=321) and control group (n=320). The probucol group was given oral probucol 500 mg twice daily for day 0 to day 3 after PCI; the control group was given only conventional therapy. All patients were given intravenous drip 0.9% sodium chloride solution before 12 to 24 hours of operation. The levels of serum creatinine (Scr), blood urea nitrogen (BUN), evaluate glomerular filtration rate (eGFR), cystatin C (Cys-C), and high-sensitivity C-reactive protein (hs-CRP), neutrophil gelatinase associated lipocalin (NGAL), superoxide dismutase (SOD) and glutathione (GSH) were measured before and 72 h after the PCI operation in both groups. The incidence rates of CIN, the adverse events during hospitalization and postoperative 14-day follow-up were recorded in two groups. Results: There was no statistically significantly difference in the levels of Scr, BUN, eGFR, Cys-C, hs-CRP, NGAL, SOD and GSH between the two groups before PCI (P>0.05). The levels of serum Scr, BUN, Cys-C, hs-CRP, NGAL, SOD and GSH after operation in the two groups were higher than those before the operation (P<0.05). The levels of hs-CRP and NGAL in the probucol group were lower than those in the control group [(10±4) vs (11±4)mg/L, (25±8)vs (34±7)U/ml, P<0.05]. The levels of eGFR, SOD and GSH in probucol group were higher than those in control group [(80±27) vs (72±26) ml·min(-1)·1.73 m(-2,) (67±9) vs (58±8)U/ml, (4.6±0.9) vs (3.9±0.8)U/ml, P<0.05]. The incidence of CIN was 4.0% in the probucol group and 10.9% in the control group, and the difference was statistically significant (P<0.05, χ(2)=-3.31). Multivariate Logistic regression analysis showed that probucol was an independent protective factor for CIN (OR=0.334, 95%CI 0.172-0.648, P=0.001). There were no adverse events such as myasthenia gravis, abnormal liver function and cardiovascular events during the hospitalization and 14-day follow-up. Conclusions: Probucol can reduce the incidence of contrast-induced nephropathy after PCI. The protection mechanism is related with its anti-inflammatory and anti-oxidative stress effects, and it has good safety.

Effect of miR-203 expression on myocardial fibrosis.

OBJECTIVE: Cardiovascular disease is one of the diseases threatening human health. Myocardial fibrosis is a major cause of cardiovascular diseases. Studies have shown that over expression of miR-203 can inhibit the fibrosis. Therefore, in this study, the effect of differential expression of miR-203 on fibrosis of cultured mouse cardiomyocytes was investigated. MATERIALS AND METHODS: Activators and inhibitors of miR-203 were designed according to the sequence of miR-203, synthesized, and transfected into mouse cardiomyocytes to establish activator group, inhibitor group, and control group. The expression levels of fibrosis-related factors including FN, CTGF, and TGF-ß1 were measured by Western blot and RT-PCR 24 h and 36 h after transfection. RESULTS: Over-expression of miR-203 in mouse cardiomyocytes significantly decreased the expression levels of TGF-ß1, CTGF, and FN in a time-dependent manner, compared with that in the control group (p <0.05). Inhibition of miR-203 expression in mouse cardiomyocytes significantly increased the expression levels of TGF-ß1, CTGF, and FN 36 h after transfection, compared with that in the control group (p < 0.05). No significant differences were seen in the expression levels of TGF-ß1, CTGF, and FN 24 h after transfection, compared with that in the control group (p >0.05). CONCLUSIONS: Over-expression of miR-203 in mouse cardiomyocytes significantly decreased the expression levels of TGF-ß1, CTGF, and FN, which might be used as a detection index for prediction of fibrosis.

Tag polymorphisms of solute carrier family 12 member 3 gene modify the risk of hypertension in northeastern Han Chinese.

Converging evidence suggests that the gene encoding solute carrier family 12 member 3 (SLC12A3) is a logical candidate involved in the underlying cause of hypertension. We therefore selected four tag polymorphisms (rs2304483, rs5804, rs8063291 and rs6499857) from SLC12A3 gene to investigate their individual and interactive associations with hypertension in northeastern Han Chinese. There were 1009 hypertensive patients and 756 normotensive controls. Data were analyzed by Haplo.Stats and multifactor dimensionality reduction (MDR) softwares, and risk estimates were expressed as odds ratio (OR) and 95% confidence interval (95% CI). Overall, there were significant differences in the genotype (P=0.002) and allele (P=0.002) distributions of rs5804 between patients and controls. Compared with the most common haplotype A-C-T-G, haplotype G-C-T-G that was overrepresented in controls (P<0.001) reduced the crude and adjusted risk of hypertension by 36% (OR 0.64; 95% CI 0.50-0.81; P<0.001) and 39% (OR 0.61; 95% CI 0.48-0.79; P<0.001), respectively. Further interaction analyses identified an overall best MDR model including rs5804 and body mass index (P=0.001), which was validated by logistic regression analysis. Taken together, our findings demonstrate a predominant role played by SLC12A3 gene rs5804 in determining hypertension risk among northeastern Han Chinese. Moreover, the interaction of this polymorphism with obesity can enhance risk prediction.

Clinical efficacy and immunological impact of tacrolimus in Chinese patients with generalized myasthenia gravis.

In this multicenter, open-label pilot study, the efficacy, safety, and immunological impact of tacrolimus in Chinese patients with generalized myasthenia gravis are assessed. Forty-seven generalized myasthenia gravis (MG) patients were enrolled into this study and given 3mg/day tacrolimus for 24 weeks. The primary efficacy measurements used to monitor response to tacrolimus in MG patients were the Osserman grade, the quantitative MG score (QMGS) recommended by the MGFA, the MG-specific manual muscle testing (MMT) score, and the MG-related activities of daily living (MG-ADL) scale. Also, reduction in steroid doses was used to monitor the effect of tacrolimus. Clinical evaluations were conducted at weeks 4, 8, 12, 16, 20, and 24, while immunological parameters were measured at weeks 4, 12, and 24. Measurements of the Osserman grade, QMGS, MMT, and MG-ADL all suggested improvement in patient health by the fourth week of treatment. Steroid dosage was reduced during the course of the study in 74.2% of the forty-three patients who completed the study. There were thirty-one reported adverse events in the study. Only one was considered serious. We found that tacrolimus reduced levels of the IFN-γ, IL-2, IL-10, and IL-13 cytokines and induced the proliferation of tolerogenic plasmacytoid dendritic cells after treatment. Tacrolimus did not change the population of T cell subtypes but did steadily reduce the population of BAFF-R(+) CD19(+) B cells over the course of the study. Our results show that tacrolimus improves the clinical condition of MG patients and is well tolerated. The decrease in IL-13 and reduction of BAFF-R(+) CD19(+) B cells may be related to the therapeutic effect of tacrolimus.

A putative mechanism on remission of multiple sclerosis during pregnancy: estrogen-induced indoleamine 2,3-dioxygenase by dendritic cells.

The basis for the reduced relapse rate of multiple sclerosis (MS) during pregnancy remains unexplained but, if defined, could create novel treatment options. Estrogen constitutes one candidate molecule, but the mechanism by which estrogen may affect MS during pregnancy is unclear. In this study, we used monocyte-derived dendritic cells (DCs) from MS patients to explore the estrogen (17-beta-estradiol)-related pathway of immune modulation. Estrogen induced the expression of indoleamine 2,3-dioxygenase (IDO) on DCs, limiting T-cell proliferation and both Th1 and Th2 cytokine production. The suppression of T-cell proliferation mediated by estrogen-exposed DCs was partly abolished by the IDO-inhibitor, 1-methyl-dl-tryptophan, indicating that estrogen-exposed DCs induced IDO-dependent T-cell suppression. Our data support the hypothesis that the change in the clinical course of MS observed in pregnancy may be related to the estrogen-DC-IDO axis, which could represent a novel target for MS therapy.

G-CSF and neuroprotection: a therapeutic perspective in cerebral ischaemia.

In several experimental studies of cerebral ischaemia, G-CSF (granulocyte colony-stimulating factor) exerted neuroprotective effects through different mechanisms, including mobilization of haemopoietic stem cells, anti-apoptosis, neuronal differentiation, angiogenesis and anti-inflammation. Hence, G-CSF not only inhibits neuron death, but also generates 'new' neural tissue formation. A small pilot trial reports on the safety and feasibility of G-CSF therapy in stroke patients. According to this evidence, we can speculate that G-CSF, being used either alone or in combination with another agent, should have a dual activity beneficial both to acute neuronal protection and long-term plasticity after cerebral ischaemia, thus proposing that G-CSF is an ideal new drug for stroke and neurodegenerative diseases.

Extent of white matter lesions is related to acute subcortical infarcts and predicts further stroke risk in patients with first ever ischaemic stroke.

OBJECTIVE: To investigate whether the extent of white matter lesions (WML) on fluid attenuated inversion recovery (FLAIR) MRI sequences is an independent risk factor for recurrent stroke, and to document the pattern of acute cerebral infarcts using diffusion weighted imaging (DWI) in patients with different severities of WML. METHODS: In a prospective cohort study, 228 consecutive stroke patients were studied between 1999 and 2001 in a community hospital. The severity of WML was graded as 0 (no WML), 1 (mild), 2 (moderate), or 3 (severe) according to the FLAIR appearances. DWI was used to document the location and size of the infarct. RESULTS: 31 patients had grade 0 WML, 69 had grade 1, 59 had grade 2, and 69 had grade 3. Age was independently associated with WML on logistic regression analysis (p = 0.0001). Acute cerebral infarcts in deep white matter were correlated with increasing severity of WML. On a median follow up of 23.0 months, life table analysis showed that recurrent stroke was related to the severity of WML (recurrence rate 7.8% in grade 0, 9.3% in grade 1, 17.7% in grade 2, 43.7% in grade 3; p = 0.0001). Survival was reduced in patients with severe WML (p = 0.0068). A Cox proportional hazards model showed WML to be predictive of recurrent stroke (p = 0.000, hazard ratio = 4.177 (95% confidence interval, 2.038 to 8.564)) and also for survival (p = 0.040, hazard ratio = 2.021 (1.032 to 3.960)). CONCLUSIONS: Patients with severe leukoaraiosis have increased risk of deep subcortical stroke and a higher risk of recurrent stroke.

Correlation between serum level of neuron-specific enolase and long-term functional outcome after acute cerebral infarction: prospective study.

OBJECTIVE: To determine the value of measuring serum levels of neuron-specific enolase in predicting extent of disease and short- and long-term functional outcome after acute cerebral infarction. DESIGN: Prospective study. SETTING: Neurology departments at two university teaching hospitals, Shanghai. PATIENTS: Thirty-eight patients who presented for acute cerebral infarction between October 1998 and October 2000 were divided into two groups: those whose infarction extended to the cerebral cortex in the carotid artery region (cortical group) and those with an infarction in the subcortical carotid artery region (subcortical group). MAIN OUTCOME MEASURES: Using a solid-phase enzyme immunoassay, we measured serum levels of neuron-specific enolase on admission and on days 2, 3, and 15. Infarct volume was measured by computed tomography on day 5. The Activities of Daily Living scale was used to assess the clinical outcome at 1-, 3-, and 6-month follow-up after onset. RESULTS: Mean (standard deviation) serum neuron-specific enolase levels were significantly higher among patients with acute cerebral infarction than among controls (18.48 [16.61] ng/mL versus 9.00 [2.70] ng/mL; P<0.001). The neuron-specific enolase level was also higher in the cortical group than in the subcortical group (33.54 [29.71] ng/mL versus 15.97 [5.91] ng/mL; P<0.01). Levels peaked after 2.11 (0.86) days and correlated positively with the infarct volume (r=0.81; P<0.01) and negatively with clinical outcome at 1 month (r= -0.37; P<0.05), 3 months (r= -0.45; P<0.01), and 6 months (r= -0.65; P<0.001), as assessed on the Activities of Daily Living scale. CONCLUSION: Serum neuron-specific enolase levels after cerebral infarction may be a useful marker to predict infarct volume and short- or long-term functional outcome.

Prevalence and predictors of renal artery stenosis in Chinese patients with coronary artery disease.

BACKGROUND: Ischaemic nephropathy is currently a major public health issue in atherosclerotic populations. Although atherosclerotic cardiovascular disease in Asia has reached epidemic proportions over the last two decades, there is little published data on the prevalence of atherosclerotic renal artery stenosis (ARAS) in Oriental subjects. Because ARAS may be clinically silent until end-stage renal failure sets in, it is important to identify patients with significant but clinically unsuspected ARAS. ARAS and coronary artery disease (CAD) often coexist. AIMS: The purpose of the present study was to evaluate the prevalence and predictors of ARAS among Chinese patients with CAD. METHODS: A total of 230 consecutive Chinese patients with CAD confirmed by coronary angiography underwent an abdominal aortogram in the same sitting to screen for ARAS. Patient demographics and comorbidities were analysed for any association with ARAS. RESULTS: A total of 34 (14.8%) patients was found to have significant ARAS. Age and multivessel CAD were independent predictors of ARAS. Hypertension, renal insufficiency, extracranial cerebrovascular disease and female gender were also associated with a higher risk of ARAS but did not independently predict ARAS. CONCLUSION: Clinically silent yet angiographically significant ARAS is common among CAD patients. The prevalence and predictors of ARAS among Chinese patients with CAD are similar to those reported for Caucasian subjects. Underlying ARAS should be suspected in CAD patients with such comorbidities as hypertension, renal insufficiency, extracranial cerebrovascular disease, and more so in the elderly and those with multivessel disease.

Binding of the initiation factor sigma(70) to core RNA polymerase is a multistep process.

The interaction of RNA polymerase and its initiation factors is central to the process of transcription initiation. To dissect the role of this interface, we undertook the identification of the contact sites between RNA polymerase and sigma(70), the Escherichia coli initiation factor. We identified nine mutationally verified interaction sites between sigma(70) and specific domains of RNA polymerase and provide evidence that sigma(70) and RNA polymerase interact in at least a two-step process. We propose that a cycle of changes in the interface of sigma(70) with core RNA polymerase is associated with progression through the process of transcription initiation.

A coiled-coil from the RNA polymerase beta' subunit allosterically induces selective nontemplate strand binding by sigma(70).

For transcription to initiate, RNA polymerase must recognize and melt promoters. Selective binding to the nontemplate strand of the -10 region of the promoter is central to this process. We show that a 48 amino acid (aa) coiled-coil from the beta' subunit (aa 262--309) induces sigma(70) to perform this function almost as efficiently as core RNA polymerase itself. We provide evidence that interaction between the beta' coiled-coil and region 2.2 of sigma(70) promotes an allosteric transition that allows sigma(70) to selectively recognize the nontemplate strand. As the beta' 262--309 peptide can function with the previously crystallized portion of sigma(70), nontemplate recognition can be reconstituted with only 47 kDa, or 1/10 of holoenzyme.

[The development of cerebral circulation analyzer].

In this paper a new cerebral circulation analyzer is introduced, inducing the main structure, the operating principle, the software program and its clinical applications. We can get the cerebrovascular hemodynamics indexes such as resistance, compensatorg blood flow etc., from the blood velocity, pressure waveform, and arterial diameter detected in carotid and vertebral arteries.

Cardioplegia and ischemia in the canine heart evaluated by 31P magnetic resonance spectroscopy.

BACKGROUND: Warm continuous blood cardioplegia provides excellent protection, but must be interrupted by ischemic intervals to aid visualization. We hypothesized that (1) as ischemia is prolonged, the reduced metabolic rate offered by cooling gives the advantage to hypothermic cardioplegia; and (2) prior cardioplegia mitigates the deleterious effects of normothermic ischemia. METHODS: Isolated cross-perfused canine hearts underwent cardioplegic arrest followed by 45 minutes of global ischemia at 10 degrees C or 37 degrees C, or 45 minutes of normothermic ischemia without prior cardioplegia. Left ventricular function was measured at baseline and during 2 hours of recovery. Metabolism was continuously evaluated by phosphorus-31 magnetic resonance spectroscopy. RESULTS: Adenosine triphosphate was 71% +/- 4%, 71% +/- 7%, and 38% +/- 5% of baseline at 30 minutes, and 71% +/- 4%, 48% +/- 5%, and 39% +/- 6% at 42 minutes of ischemia in the cold ischemia, warm ischemia, and normothermic ischemia without prior cardioplegia groups, respectively. Left ventricular systolic function, left ventricular relaxation, and high-energy phosphate levels recovered fully after cold cardioplegia and ischemia. Prior cardioplegia delayed the decline in intracellular pH during normothermic ischemia initially by 9 minutes, and better preserved left ventricular relaxation during recovery, but did not ameliorate the severe postischemic impairment of left ventricular systolic function, marked adenosine triphosphate depletion, and creatine phosphate increase. Left ventricular distensibility decreased in all groups. CONCLUSIONS: When cardioplegia is followed by prolonged ischemia, better protection is provided by hypothermia than by normothermia. Prior cardioplegia confers little advantage on recovery after prolonged normothermic ischemia but delays initial ischemic metabolic deterioration, which would contribute to the safety of brief interruptions of warm cardioplegia.

The interface of sigma with core RNA polymerase is extensive, conserved, and functionally specialized.

The sigma subunit of eubacterial RNA polymerase is required throughout initiation, but how it communicates with core polymerase (alpha(2)betabeta') is poorly understood. The present work addresses the location and function of the interface of sigma with core. Our studies suggest that this interface is extensive as mutations in six conserved regions of sigma(70) hinder the ability of sigma to bind core. Direct binding of one of these regions to core can be demonstrated using a peptide-based approach. The same regions, and even equivalent residues, in sigma(32) and sigma(70) alter core interaction, suggesting that sigma(70) family members use homologous residues, at least in part, to interact with core. Finally, the regions of sigma that we identify perform specialized functions, suggesting that different portions of the interface perform discrete roles during transcription initiation.

Structural features required for the interaction of the Hsp70 molecular chaperone DnaK with its cochaperone DnaJ.

Hsp70 family members together with their Hsp40 cochaperones function as molecular chaperones, using an ATP-controlled cycle of polypeptide binding and release to mediate protein folding. Hsp40 plays a key role in the chaperone reaction by stimulating the ATPase activity and activating the substrate binding of Hsp70. We have explored the interaction between the Escherichia coli Hsp70 family member, DnaK, and its cochaperone partner DnaJ. Our data show that the binding of ATP, subsequent conformational changes in DnaK, and DnaJ-stimulated ATP hydrolysis are all required for the formation of a DnaK-DnaJ complex as monitored by Biacore analysis. In addition, our data imply that the interaction of the J-domain with DnaK depends on the substrate binding state of DnaK.

Interaction of the Hsp70 molecular chaperone, DnaK, with its cochaperone DnaJ.

Chaperones of the Hsp70 family bind to unfolded or partially folded polypeptides to facilitate many cellular processes. ATP hydrolysis and substrate binding, the two key molecular activities of this chaperone, are modulated by the cochaperone DnaJ. By using both genetic and biochemical approaches, we provide evidence that DnaJ binds to at least two sites on the Escherichia coli Hsp70 family member DnaK: under the ATPase domain in a cleft between its two subdomains and at or near the pocket of substrate binding. The lower cleft of the ATPase domain is defined as a binding pocket for the J-domain because (i) a DnaK mutation located in this cleft (R167H) is an allele-specific suppressor of the binding defect of the DnaJ mutation, D35N and (ii) alanine substitution of two residues close to R167 in the crystal structure, N170A and T173A, significantly decrease DnaJ binding. A second binding determinant is likely to be in the substrate-binding domain because some DnaK mutations in the vicinity of the substrate-binding pocket are defective in either the affinity (G400D, G539D) or rate (D526N) of both peptide and DnaJ binding to DnaK. Binding of DnaJ may propagate conformational changes to the nearby ATPase catalytic center and substrate-binding sites as well as facilitate communication between these two domains to alter the molecular properties of Hsp70.

Presynaptic changes of neuromuscular transmission in mice induced by passive transfer of plasma with anti-presynaptic membrane receptor antibodies from a patient with myasthenia gravis.

Electrophysiological studies were conducted in three groups of mice to determine the possible involvement of the antibodies to presynaptic membrane receptor (PsmR), a beta-bungarotoxin (beta-BuTX) binding protein, in the pathogenesis of myasthenia gravis (MG). Mice were untreated (untreated group, n = 8) or were injected (i.p.) with blood plasma from a MG patient, which contained antibodies to PsmR, at a dose of 1 ml per day for more than 2 months (MG plasma group, n = 12) or with plasma from healthy subjects (normal plasma group, n = 10). Prior to plasma injection, cyclophosphamide was given at 300 mg/kg (i.p.) to all three groups. About three weeks after plasma injection, most mice of the MG plasma group became less mobile in comparison with those of the two control groups. Electrophysiological recording showed three main changes in the MG plasma group: (1) the increase in the frequency of miniature endplate potentials (mEPPs) induced by Krebs solution with high K+ concentration (17.5 mM) was significantly lowered, which was confirmed in mice injected with IgG (50 mg per day) from this patient for two days; (2) the quantal content of EPP was decreased; and (3) the decrement in the amplitude of a train EPP (50 Hz) was quickened. Our results suggest that this experimental model is different from that of Lambert-Eaton myasthenic syndrome and that antibodies to PsmR may also be involved in the pathogenesis of MG.

Retardation of pain development: a case of recovery from congenital insensitivity to pain.

Congenital analgesia is a rare genetic disorder. We report here that a 12-year-old boy was able to recover from congenital insensitivity to pain. Neurological examinations revealed that there was a 'stocking' distribution of pain decrement on the lower extremities under the patient's knee joints. Magnetic Resonance Imaging (MRI) of his brain showed gyrus thinning with sulcus widening at both sides of the parietal lobe. Southern blot hybridization probed with cDNAs of various opioid receptors did not detect any significant abnormality. Our results suggest that this rare case may not be genetically determined.

Ischemic intervals during warm blood cardioplegia in the canine heart evaluated by phosphorus 31-magnetic resonance spectroscopy.

OBJECTIVE: Warm blood cardioplegia requires interruption by ischemic intervals to aid visualization. We evaluated the safety of repeated interruption of warm blood cardioplegia by normothermic ischemic periods of varying durations. METHODS: In three groups of isolated cross-perfused canine hearts, left ventricular function was measured before and for 2 hours of recovery after arrest, which comprised four 15-minute periods of cardioplegia alternating with three ischemic intervals of 15, 20, or 30 minutes (I15, I20, and I30). Metabolism was continuously measured by phosphorus 31-magnetic resonance spectroscopy. RESULTS: Adenosine triphosphate level fell progressively as ischemia was prolonged; after recovery, adenosine triphosphate was 99% +/- 6%, 90% +/- 1% (p = 0.0004 vs control), and 68% +/- 3% (p = 0.0002) of control levels in I15, I20, and I30, respectively. Intracellular acidosis with ischemia was most marked in I30. After recovery, left ventricular maximal systolic elastance at constant heart rate and coronary perfusion pressure was maintained in I15 but fell to 85% +/- 3% in I20, (p = 0.003) and to 65% +/- 6% (p = 0.003) of control values in I30, while relaxation (tau) was prolonged only in I30 (p = 0.007). CONCLUSIONS: Hearts recover fully after three 15-minutes periods of ischemia during warm blood cardioplegia, but deterioration, significant with 20-minute periods, is profound when the ischemic periods are lengthened to 30 minutes. This suggests that in the clinical setting warm cardioplegia can be safely interrupted for short intervals, but longer interruptions require caution.