Abstract P6-03-03: The Q-CROC-3 project reveals novel genomic alterations in triple negative breast cancers in residual tumors after neoadjuvant chemotherapy

The prognosis of triple negative breast cancer that shows resistance and/or incomplete response to cytotoxic chemotherapy is poor. In order to understand the mechanisms of resistance to chemotherapy and the genomic evolution of TNBCs treated with chemotherapy, an international multi-center biopsy-driven clinical trial was created for the collection and study of drug-resistant primary and metastatic freshly frozen tumors (Q-CROC-03: NCT01276899). We consented 60 patients with operable TNBC undergoing neoadjuvant Anthracycline/Taxane-based chemotherapy for pre and post-treatment biopsies as well as collection of residual tumor at the time of surgery and serial blood sampling. In 12-15 patients, adequate residual tumor material was available for genomic studies, which included whole exome sequencing, array CGH, gene expression microarray profiling and RNAseq of paired tumors. Whole exome sequencing revealed clonal shifts as well as the relatively infrequent appearance of novel mutations in individual tumors, without any recurrently detected variants. Array CGH revealed a remarkable stability in the number of DNA copy number alterations with a few functional alterations enriched for in the residual tumor, including an amplicon involving the NFIB gene. Finally, gene expression profiling showed shifts towards the immune-modulatory and basal TNBC subtypes after chemotherapy as well as an increase in the expression of several targetable genes, including DUSP1, a dual specificity phosphatase. In the 4 cases of primary and matching metastatic tumors, the post-NAC residual tumor had acquired changes many of which persisted in the metastatic sites, indicating that the analysis of the residual tumors can provide a partial picture of genomic changes present in metastases but not in the primary tumor. In summary, the genomic characterization of residual post-NAC tumor tissue provides important information for the development of novel therapeutic strategies for drug-resistant TNBCs as well as a portrait of genomic evolution of TNBCs subjected to chemotherapy.

Citation Format: Basik M, Aguilar-Mahecha A, Lafleur J, Bareke E, Przybytkowski E, Alirezaie N, Discepola F, Légaré S, Kovacina B, Lan C, Mihalcioiu CL, Robidoux A, Marcus E, Roy J-A, Pelmus M, Aleynikova O, Nabavi S, Tonellato P, Majewski J. The Q-CROC-3 project reveals novel genomic alterations in triple negative breast cancers in residual tumors after neoadjuvant chemotherapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-03-03.

Cardiac rehabilitation in a pediatric patient with heart retransplantation. A single case study

BACKGROUND

Cardiac rehabilitation (CR) after heart transplantation is known to benefit physical capacity in adults, but the advantages of CR on pediatric patients with heart retransplantation remain undetermined.

AIM

The purpose of the present study was to report the effect of structured CR for a boy receiving heart transplantations twice.

DESIGN

Single case study.

SETTING

Inpatient and outpatient rehabilitation department.

POPULATION

A pediatric patient underwent heart transplantation due to dilated cardiomyopathy at 13.6 year-old and retransplantation owing to severe cardiac allograft vasculopathy at 16.2 year-old.

METHODS

CR was arranged after both transplantations. Bicycle or treadmill exercises were conducted three times weekly with the intensity adjusted to the ventilatory threshold. Serial cardiopulmonary exercise tests were performed to evaluate the sequential cardiorespiratory function changes using the peak oxygen uptake (VO₂peak) as the primary outcome.

RESULTS

The patient had undergone 10 times of exercise tests during rehabilitation. The VO₂peak increased from 12.27 to 15.63 mL·kg-1·min-1 within 6 months after the primary transplantation. However, the VO₂peak dropped intensively after a rejection episode and failed to improve since the development of cardiac allograft vasculopathy. Following retransplantation, the VO₂peak appeared worse initially but increased gradually with rehabilitation. One year subsequent to retransplantation, the VO₂peak reached 17.7 mL·kg-1·min-1 with a 7.22 mL·kg-1·min-1 improvement compared with his baseline value.

CONCLUSION

Structured CR improves aerobic capacity of a pediatric patient with heart retransplantation.

CLINICAL REHABILITATION IMPACT

CR is safe and beneficial for pediatrics with heart retransplantation. Cardiopulmonary exercise testing can be considered as an adjuvant tool for detecting rejection or cardiac allograft vasculopathy in pediatric heart transplantation recipients.

A novel nonsense mutation of the GPR143 gene identified in a Chinese pedigree with ocular albinism

Background

The purpose of this study was to elucidate the molecular basis of ocular albinism type I in a Chinese pedigree.

Methodology/Principal Findings

Complete ophthalmologic examinations were performed on 4 patients, 7 carriers and 17 unaffected individuals in this five-generation family. All coding exons of four-point-one (4.1), ezrin, radixin, moesin (FERM) domain-containing 7 (FRMD7) and G protein-coupled receptor 143 (GPR143) genes were amplified by polymerase chain reaction (PCR), sequenced and compared with a reference database. Ocular albinism and nystagmus were found in all patients of this family. Macular hypoplasia was present in the patients including the proband. A novel nonsense hemizygous mutation c.807T>A in the GPR143 gene was identified in four patients and the heterozygous mutation was found in seven asymptomatic individuals. This mutation is a substitution of tyrosine for adenine which leads to a premature stop codon at position 269 (p.Y269X) of GPR143.

Conclusions/Significance

This is the first report that p.Y269X mutation of GPR143 gene is responsible for the pathogenesis of familial ocular albinism. These results expand the mutation spectrum of GPR143, and demonstrate the clinical characteristics of ocular albinism type I in Chinese population.

The effect of early cardiac rehabilitation on health-related quality of life among heart transplant recipients and patients with coronary artery bypass graft surgery

PURPOSE

To investigate the effect of an early postoperative outpatient cardiac rehabilitation program to health-related quality of life among heart transplantation recipients (HTR) and patients with coronary artery bypass graft (CABG) surgery.

METHODS

The study included 45 clinically stable HTR (age: 47 ± 14 years; 36 men, 9 women) and 34 patients with CABG (age: 57.2 ± 12.5 years; 27 men, 7 women). HTR started rehabilitation 70 ± 33 days after transplantation; patients with CABG started training 36 ± 18 days after surgery. Patients participated in a 12-week supervised exercise training program three times per week. Each training session comprised 10 minutes of warm-up, 25 to 30 minutes of cycling or treadmill walking, and 10 minutes of cooldown. The exercise intensity was set at 50% to 80% of peak oxygen uptake (V̇O(2peak)) according to the patient's condition. The health-related quality of life of subjects was evaluated by the Medical Outcomes Trust 36-item health survey (SF-36) at baseline and upon the completion of rehabilitation.

RESULTS

At baseline, the HTR group showed lower V̇O(2peak) than the CABG group, but the health-related quality of life was similar between the two groups. After training, both groups exhibited an increase of 3.6 mL·kg(-1)·min(-1) in V̇O(2peak) and improvement of physical component in health-related quality of life. The HTR group showed a significant increase of SF-36 scores in physical functioning (59.7 ± 18.9 to 77.0 ± 14.0), physical role (21.1 ± 34.1 to 38.3 ± 37.9), bodily pain (57.4 ± 24.3 to 73.6 ± 21.5), social functioning (63.6 ± 23.4 to 72.8 ± 22.1), emotional role (59.2 ± 43.7 to 76.3 ± 37.4), and mental health (67.1 ± 17.9 to 73.4 ± 14.6). The CABG group only exhibited increased scores in physical functioning (60.0 ± 22.9 to 73.4 ± 18.0), physical role (19.1 ± 24.9 to 27.9 ± 38.3), bodily pain (57.1 ± 20.0 to 70.3 ± 16.1), and social functioning (54.0 ± 21.3 to 69.9 ± 21.1).

CONCLUSIONS

Early postoperative cardiac rehabilitation significantly improved physical capacity and quality of life among heart transplant recipients and patients with CABG. Additionally, HTR showed greater improvement in health-related quality of life than patients with CABG regardless of lower physical capacity.

Expression of the three nitric oxide synthase isoforms and nitric oxide level in the rat heart during cold storage and blood reperfusion

Maintenance of nitric oxide (NO) homeostasis is an important concept for myocardial protection. Here, we have investigated the NO pathway by analysing total nitrate concentration (NOx) and NO synthase (NOS) isoforms expression as well as the myocardial integrity by lactate dehydrogenase and creatine kinase contents in the rat heart graft arrested by CRMBM solution, submitted to 3 hr cold ischemia in the same solution and 24 hr blood reperfusion following heterotopic abdominal heart transplantation. NOx level was similar to baseline value after ischemia and significantly increased after 24 hr reperfusion. NOS isoforms expression was highly modulated after cold ischemia followed by blood reperfusion. Endothelial NOS expression was decreased after ischemia but restored after 24 hr reperfusion. Neuronal NOS expression was drastically decreased after ischemia and 24 hr reperfusion. Inducible NOS protein was present only after 24 hr reperfusion. Cold ischemia induced a severe loss of creatine kinase without any modification after blood reperfusion. In conclusion, we show here that CRMBM solution did not increase NO production during ischemia but induced an enhanced synthesis of NO during reperfusion which may be related to restoration of endothelial NOS expression and/or induction of inducible NOS expression.

A multicenter phase II study of pemetrexed (P), cisplatin (C), and bevacizumab (B) in patients (pts) with advanced malignant mesothelioma (MM)

7578

Background: Vascular endothelial growth factor (VEGF) is a key growth factor for MM. In pre-clinical models, anti-VEGF antibodies inhibit MM proliferation. Standard chemotherapy for MM, pemetrexed + cisplatin, yields a response rate of 41%, progression-free survival (PFS) of 5.7 months (mo) and median overall survival (OS) of 12.1 mo. We added the anti-VEGF antibody B to PC in an ongoing phase II multi-center study in MM pts. Methods: Eligible pts have unresectable, histologically-confirmed MM, no prior chemotherapy, and PS 0–1. Pts receive C 75 mg/m2, P 500 mg/m2 and B 15 mg/kg Q21 days for 6 cycles, then B Q21 days until progression. CT scans are obtained Q 2 cycles. Primary endpoint: Progression-fere survival (PFS). Correlative studies include IHC for the VEGF/KDR complex and PCR for simian virus 40 (sv40) T antigen. Results: 43 pts enrolled at 4 centers from 3/06 to 12/08; currently, 34 are evaluable for PFS and 36 for toxicity. Pt characteristics: male 88%; median age 66 (range 24–81); histology: epithelial 62%, sarcomatoid 15%, biphasic 20%, unknown 3%; site of origin: pleural 85%, peritoneal 12%, tunica vaginalis 3%; PS 0 32%, PS 1 68%; thrombocytosis (>400) 32%. Cycles administered 229 (median 4, range 1–18). Grade 3/4 toxicity (%pts): neutropenia 8%; anemia 0%; thrombocytopenia 3%; thrombosis 11%; hypertension 8%; vomiting 8%; mucositis 6%; CVA 3%; proteinuria 0%; perforation 0%. Partial response: 41%, stable disease: 35%. Median PFS: 5.6 mo (95% CI: 4.1, 7.2). Median OS 11.5 mo (95% CI: 9.4, 24). Conclusions: These data suggest that the addition of B to PC does not improve PFS when compared with historical controls of PC in advanced MM pts. Correlative studies evaluating the VEGF/KDR complex and sv40 T antigen are pending.

[Table: see text]

Gene expression profiling reveals the profound upregulation of hypoxia-responsive genes in primary human astrocytes

Oxygen is vital for the development and survival of mammals. In response to hypoxia, the brain initiates numerous adaptive responses at the organ level as well as at the molecular and cellular levels, including the alteration of gene expression. Astrocytes play critical roles in the proper functioning of the brain; thus the manner in which astrocytes respond to hypoxia is likely important in determining the outcome of brain hypoxia. Here, we used microarray gene expression profiling and data-analysis algorithms to identify and analyze hypoxia-responsive genes in primary human astrocytes. We also compared gene expression patterns in astrocytes with those in human HeLa cells and pulmonary artery endothelial cells (ECs). Remarkably, in astrocytes, five times as many genes were induced as suppressed, whereas in HeLa and pulmonary ECs, as many as or more genes were suppressed than induced. More genes encoding hypoxia-inducible functions, such as glycolytic enzymes and angiogenic growth factors, were strongly induced in astrocytes compared with HeLa cells. Furthermore, gene ontology and computational algorithms revealed that many target genes of the EGF and insulin signaling pathways and the transcriptional regulators Myc, Jun, and p53 were selectively altered by hypoxia in astrocytes. Indeed, Western blot analysis confirmed that two major signal transducers mediating insulin and EGF action, Akt and MEK1/2, were activated by hypoxia in astrocytes. These results provide a global view of the signaling and regulatory network mediating oxygen regulation in human astrocytes.

Nitric oxide pathway after long-term cold storage and reperfusion in a heterotopic rat heart transplantation model

Recent studies have suggested the involvement of the nitric oxide (NO) pathway in ischemia-reperfusion injury related to cardiac transplantation. Herein, we assessed the NO pathway by quantifying endothelial (e) and inducible (i) nitric oxide synthase (NOS) expression and total NOS activity in a rat heart transplant model during cold ischemia with Celsior cardioplegia and reperfusion. Experiments were performed using a modified Lewis-Lewis heterotopic abdominal heart transplantation with 3 or 6 hours of ischemia with or without 1 hour of blood reperfusion. NOS expression and activity were determined using Western blotting and colorimetric assays, respectively, on freeze-clamped hearts after ischemia without (n = 10) or with reflow (n = 12) compared with basal values. Hearts submitted to 3 hours of ischemia and 1 hour of reperfusion showed a postischemic rate pressure product of 5190 +/- 3047 mm Hg/min (reversible ischemia), but no contractility was observed after 6 hours of ischemia. eNOS protein levels were lower after 3 hours of ischemia compared with the basal value (P = .0005) and were further decreased after 6 hours of ischemia (P < .0001 versus basal value and P = .0018 versus 3 hours of ischemia). Reperfusion did not further decrease eNOS protein levels. iNOS protein was not detected in any condition. NOS activity was increased after 3 hours of ischemia versus basal value (P = .0065) but not after 6 hours of ischemia without any effect of reperfusion. We concluded that eNOS expression was altered during ischemia and the amplitude of the alteration depended on the duration of ischemia. Reversible ischemia was associated with increased NOS activity at the end of ischemia with no variation at reperfusion.

Dose dependent accretion of docosahexaenoic acid (DHA) in cardiac membranes of rats fed egg yolk powder enriched in DHA

We tested the hypothesis that enrichment of the diet with docosahexaenoic acid (DHA) enriched egg yolk powder could modify specifically the (n-3) fatty acids content of rat plasma, red blood cells and heart membranes. Dose-dependent effect of DHA was studied in rats supplemented during 4 weeks. Three groups of adult male rats, DHA10, DHA35 and DHA60 (n = 5 each), had their diet supplemented with 10 mg, 35 mg or 60 mg DHA/kg body weight/day, respectively. Fatty acid composition of membranes and plasma lipids were determined. A significant dose-dependent increase in DHA was observed in all three types of samples. Arachidonic acid (AA) levels did not change in heart and red blood cell membranes whereas it increased significantly in plasma with the DHA35 diet. These results contrast with that previously reported for fish oil supplementation where a decrease in AA levels was reported. Hence, DHA enriched egg yolk supplementation leads to a specific accretion of DHA without competition on AA status.

Modulation of the NO pathway during short or prolonged blood reperfusion following ischaemia in a heterotopic rat heart transplantation model

Ischemia-reperfusion injury plays a major role in graft dysfunction following transplantation. Extensive research has demonstrated that nitric oxide (NO) plays a fundamental role to protect the heart against this injury. Consequently, we quantified NO synthase (NOS) isoform protein levels in a rat heart transplant model during short and prolonged reperfusion following ischemia. Experiments were performed using a modified Lewis to Lewis heterotopic abdominal heart transplantation with a total ischemic time of 3 hours followed by 1 or 24 hours of blood reperfusion (n = 12). Heart function, as represented by the rate pressure product, increased from 7912 +/- 489 to 27067 +/- 9982 mm Hg/min (mean +/- SEM, short vs prolonged reperfusion, P = .0027). NOS isoform protein levels determined using Western blotting of freeze-clamped hearts were compared to baseline values. eNOS protein levels were significantly lower during short reperfusion compared to the basal value (P = .0077) or to prolonged reperfusion (P = .004), returning to the basal value after 24 hours of reflow. iNOS protein was not detected in the basal condition or after 1 hour of reflow, but was present after 24 hours of reflow (P = .0001 vs basal value and 1-hour reflow). nNOS protein was 69% lower after 1 hour of reflow compared with the baseline value (P = .0001), it was not restored after 24 hours of reflow (P = .002). These results suggest involvement of the NO pathway in ischemia-reperfusion injury with distinctive roles of NOS isoforms during short and prolonged reperfusion following ischemia.

Preservation of amino acids during long term ischemia and subsequent reflow with supplementation of L-arginine, the nitric oxide precursor, in the rat heart

We investigated whether L-arginine, used in heart preservation to limit endothelial damage, may influence the pool of amino acids during long term ischemia and reflow. Isolated isovolumic rat hearts (n = 23) were submitted to 8 h of hypothermic ischemia after cardioplegic arrest with the Centre de Résonance Magnétique Biologique et Médicale (CRMBM) solution with or without L-arginine (Arg and No Arg groups respectively). Hearts were freeze-clamped after ischemia (n = 11) or submitted to 60 min of reflow (n = 12) and freeze-clamped. Eight hearts were perfused aerobically for 20 min and freeze-clamped (No ischemia group). Addition of L-arginine to the CRMBM solution limited aspartate depletion and decreased lysine level at the end of ischemia. After reflow, L-arginine supplementation increased the pool of glutamate and arginine and limited the depletion of serine, asparagine, glycine and taurine. We conclude that adding L-arginine to the CRMBM cardioplegic solution during long term ischemia preserved the amino acids pool.

[A pilot study on malaria control by using a new strategy of combining strengthening infection source treatment and health education in mountainous areas of Hainan province]

AIM

To explore a new malaria control strategy that fits current epiodemiological condition and coincides with modern medicine model and the principle of cost-benefit.

METHODS

The new strategy highlights the risk villages and risk population as the focal point and integrates health education with behavioral intervention. The main anti-malaria measures consists of carrying out health education in risk villages, giving mass drug administrations in risk population staying overnight in the mountain, following up malaria cases for implementing radical cure, but without using traditional residual spraying or impregnating bednets with insecticides.

RESULTS

After having adopted the new strategy and taken the control measures, the people's knowledge about malaria increased to a higher level and the indices of malaria reduced to a lower level. The rate of bednet-using in the population was increased from 26.8% to 72.6%. The annual parasite incidence (API) of malaria was declined from 3.5% in 1994 to 1.1% in 1996 and 0.8% in 1997, and the API of falciparum malaria was declined from 1.0% to 0.3% and 0.3% respectively in the townships at the same time. The parasite rate(PR) of malaria was declined from 7.2% in May, 1995 to 2.1% in November, 1996 and 1.2% in October, 1997 and the PR of falciparum malaria was declined from 1.2% in May, 1995 to 0.1% in October, 1997. The proportion of villages without malaria cases was increased from 18.6% in 1994 to 54.2% in 1997, and the number of risk villages with a malaria incidence above 5% was reduced from 14 to 2 at the same time. The ratio of cost/benefit was 1:2.4 in 1995-1996 and 1:4.4 in 1997, showing a better economic benefit.

CONCLUSION

The expectant result has been obtained, thereby providing new experience for the malaria control in the mountainous areas of Hainan Province.

Heart rate responses and oxygen consumption during Tai Chi Chuan practice

Tai Chi Chuan (TCC) is a popular Chinese conditioning exercise, however, its exercise intensity remains controversial. The objective of this study was to determine the exercise intensity of Yang TCC by measuring heart rate (HR) responses and oxygen consumption (VO2) during practice. Fifteen men aged 39.9 +/- 9.5 yrs (range 26-56 yrs) participated in this study. Subjects had practiced classical Yang TCC for 5.8 +/- 2.4 years. HR responses and VO2 were measured during practice of TCC by using a K4 telemetry system. Blood lactate was measured before and immediately after TCC practice. Additionally, breath-by-breath measurement of cardiorespiratory function and sequential determination of blood lactate were performed during the incremental exercise of leg cycling. Measurements obtained during the TCC practice and exercise testing were compared to determine the exercise intensity of TCC. While performing TCC, the mean HR of subjects was 140 +/- 10 bpm, and the mean VO2 was 21.4 +/- 1.5 mL x kg(-1) min(-1). Compared with the data of the exercise test, the HR during practice was 58% of the heart rate range. Meanwhile, the VO2 during TCC practice was 55% of the VO2peak. Additionally, the level of blood lactate immediately after TCC practice was 3.8 mM, which reflected the level of lactate during TCC, approximated the onset of blood lactate accumulation (OBLA). The results demonstrate that TCC is an exercise with moderate intensity, and is aerobic in nature.

Rates and characteristics of lower limb amputations in Taiwan, 1997

This study aims to describe the national incidence rate and characteristics of lower limb amputations (LLA) in 1997 from an island-wide database of the national health insurance programme in Taiwan. Some 117,647 discharge records from a sampled database (1 in 20) of the National Health Insurance Research Database were analysed. This study included records (n=171) containing LLA procedures. The LLA procedure rates were obtained by multiplying the number of identified procedures by 20 as the numerator and mid-year total population of Taiwan in 1997 as the denominator. Each procedure was further analysed according to the demographic characteristics of the patients, cause and level of amputation. Summarised gender ratios of LLA procedure rates were obtained by Poisson regression analysis. The crude LLA procedure rate was 18.1 per 100,000 population per year and the crude major LLA procedure rate was 8.8 per 100,000 population per year in Taiwan in 1997. The major cause of LLA procedures was peripheral vascular disease (72%), and the toe was most frequently amputated (48%). The LLA procedure rates, which increased logarithmically with age of patients, were significantly higher in men with a summarised male to female rate ratio of 1.65. The age-standardised LLA procedure rate in Taiwan was lower than that reported in the United States, Finland, the Netherlands, the United Kingdom (Leeds, Middlesborough, and Newcastle), but higher than Spain, Italy, and Japan. The trend of an increasing proportion of PVD-related LLA procedures will prompt the health professionals to develop strategies for LLA prevention.

Tai Chi Chuan training to enhance microcirculatory function in healthy elderly men

OBJECTIVE

To evaluate cutaneous microcirculatory function in geriatric Tai Chi Chuan (TCC) practitioners.

DESIGN

Case-control study.

SETTING

Community setting.

PARTICIPANTS

Ten elderly male TCC practitioners (mean age, 69.9 +/- 1.5 yr) and 10 sedentary men with matched age and body size (mean age, 67.0 +/- 1.0 yr).

INTERVENTION

The TCC group had practiced TCC for 11.2 +/- 3.4 years (mean +/- standard error of the mean), with an exercise frequency of 5.1 +/- 1.8 times weekly. Each session included 20 minutes of warm-up, 24 minutes of TCC practice, and 10 minutes of cool down.

MAIN OUTCOME MEASURES

A graded exercise test with gas analysis was conducted on a bicycle ergometer for each subject. Skin blood flow (SkBF), cutaneous vascular conductance, and skin temperature were measured at rest and during exercise testing. Plasma nitric oxide metabolite was analyzed before and immediately after exercise.

RESULTS

The TCC group had a 34% higher VO(2)peak than the control group; it also had a higher SkBF, cutaneous vascular conductance, and skin temperature than the control group at rest and during exercise; and it also had a higher level of plasma nitric oxide metabolite than the sedentary group at rest and after exercise.

CONCLUSION

Older TCC practitioners had higher cutaneous microcirculatory function during exercise than did their sedentary counterparts. Moreover, this change may be partially mediated by enhancement of nitric oxide release.

Simultaneous study of metabolism and function following cardioplegic arrest: a novel method of evaluation of the transplanted heart in the rat

BACKGROUND

Limitations of the isolated perfused rat heart model for heart preservation studies include short study time due to the lack of stability of the preparation. We aimed to develop a new experimental model based on heterotopic heart transplantation in the rat to achieve simultaneous (31)P magnetic resonance spectroscopy (MRS) and functional study of the transplanted heart during early and late blood reperfusion.

METHODS

Twenty-five Lewis rats underwent heterotopic abdominal isograft heart transplantation and were randomized in two groups. Hearts were harvested after cardioplegic arrest induced with Centre de Résonance Magnétique Biologique et Médicale (CRMBM) solution and then stored at 4 degrees C for a total ischemic time of 3 hours. Graft contractility measurement and simultaneous (31)P MRS were performed after 1 hour and 24 hours of blood reperfusion, respectively, in groups I (n = 12) and II (n =13).

RESULTS

Contractility improved during reperfusion. The mean rate pressure product plus or minus standard error of mean increased from 11,373 +/- 1,377 mm Hg/min in group I to 24,363 +/- 3,860 mm Hg/min in group II (P = 0.003), while mean dP/dtmax increased from 1,642 +/- 173 mm Hg/sec to 2,571 +/- 333 mm Hg/sec, respectively (p = 0.03). Simultaneously, both the phosphocreatine/adenosine triphosphate (ATP) and inorganic phosphate/ATP ratios decreased from group I to group II (p = 0.025 and p = 0.015, respectively), suggesting regeneration of the intracellular pool of ATP in group II.

CONCLUSIONS

Simultaneous functional and metabolic studies of the transplanted heart are feasible in rats. Improvement in contractility during late reperfusion is contemporary with significant changes in energetic metabolism. Our model should be useful for the further improvement of heart preservation, which may result in significant clinical progress.

[Acid producing potential of a lead/zinc mine tailings at Lechang, Guangdong Province]

The acid producing potential of a Pb/Zn mine tailings at Lechang City, Guangdong Province were studied using both net acid generation (NAG) and net acid production potential (NAPP) methods. The pyritic and total sulfur contents of the tailings were 12.57% and 18.68% respectively. The NAG and NAPP values were H2SO4 220 kg.t-1 and 326 kg.t-1, and both the NAG and NAPP results indicated that the tailings had high acid forming potential. NAG was more accurate than NAPP in predicting acid forming potential of the tailings due to the uncompleted oxidization of pyritic sulfur. Analysis of samples from two profiles test indicated that the acidification major occurred on the surface (0-20 cm) of the tailings because of limited oxygen diffusion and had little effects on the tailings at lower horizons. pH values were negatively related to EC, indicated that the acid released accelerate dissolution of the solid matrix and increase in both cations and actions in solution, the extractable Pb, Zn, Cu and Cd at the acidifying tailings surface.

[Leaf decomposition of two species in a mangrove community in Futian of Shenzhen]

Using litter bags, the authors studied the dynamics of dry weight and organic C, N and P of leaves of two species (Kandelia candel, Aegiceras corniculatum) in a mangrove community in Shenzhen during their decomposition in situ. Leaves of K. candel degraded more rapidly than those of A. corniculatum. For A. corniculatum, it needed 35 days to lose half initial ash-free dry weights (AFDW) of the leaves, while for K. candel, only 12 days. Despite the difference in loss rate of litter bags with the two species, the dynamics of organic C, N and P of leaf detritus followed the same pattern. During decomposition, the N concentration of leaf detritus of both species rose up sharply, and then decreased gradually from the peak. The P level declined slightly, and then rose up slowly. The concentration of C remained fairly constant throughout the experiment. No significant difference in decomposition rates of the leaves of A. corniculatum was found when they degraded at different positions along tidal gradient within the mangrove ecosystem.

Energy expenditure of wheeling and walking during prosthetic rehabilitation in a woman with bilateral transfemoral amputations

OBJECTIVE

To compare the energy expenditure of locomotion by wheelchair with that required for prosthetic ambulation in a person with bilateral transfemoral (TF) amputations.

DESIGN

Observational, single patient, descriptive.

SETTING

An 80-meter long rectangular hallway in a rehabilitation unit.

PATIENT

A 41-year-old woman with bilateral TF amputations that were performed 79 days before her admission to the rehabilitation unit.

MAIN OUTCOME MEASURES

The oxygen uptake, oxygen cost, heart rate, speed, cadence, and stride length of walking measured during a 4-month course of prosthetic rehabilitation. Five locomotion conditions were evaluated: (1) wheelchair propulsion, (2) walking with short-leg prostheses (stubbies) and a walker, (3) long-leg prostheses and a walker, (4) long-leg prostheses without knee mechanism and axillary crutches, and (5) long-leg prostheses with right polycentric knee and left locked knee and axillary crutches. A portable and telemetric system was used to measure the metabolic parameters. An arm ergometry graded exercise test was performed at the end of rehabilitation.

RESULTS

Oxygen cost (range, 466%--707% of that of wheeling) and heart rate (range, 106%--116% of that of wheeling) were higher during walking with various combinations of prostheses and walking aids. The speed of prosthetic walking was only 24% to 33% of that of wheeling. Our patient preferred using a wheelchair to prosthetic walking after discharge.

CONCLUSIONS

People with bilateral TF amputations require very high cardiorespiratory endurance to fulfill the energy demand during prosthetic rehabilitation. The high energy cost of prosthetic walking will limit its application in daily activities.