Hepatobiliary Scintigraphy in the Preoperative Evaluation of Potential Living Liver Donors.

BACKGROUND: Graft selection strategy in living donor liver transplantation (LDLT) is usually multifactorial, but special attention is paid to the determination of donor liver volumes to minimize any risk of posthepatectomy liver failure (PHLF). Hepatobiliary scintigraphy (HBS) with single-photon-emission computed tomography allows for the measurement of total and future liver remnant function (FLR-F) and has been shown to predict the risk of PHLF more accurately than liver volumetry. METHODS: Since November 2016, HBS has been performed at our Institution in every candidate to major hepatectomy, including potential living liver donors. RESULTS: Thirty-seven consecutive patients were submitted to HBS, of whom 7 were potential living liver donors. After completed hepatectomy (n = 27), the median FLR-F of patients who developed PHLF (n = 9) was 1.72%/min/m2 (range 1.40-2.78) compared to that of patients who did not (n = 18), which was 4.02%/min/m2 (range 1.15-12.08). Three donors underwent operations (1 right hepatectomy and 2 left hepatectomies). In the only donor who developed PHLF, the FLR accounted for the 37% of the total liver volume, whereas the FLR represented only the 31% of the total liver function (TL-F = 11.29%/min) with a resulting FLR-F of 2.05%/min/m2. CONCLUSIONS: The present study suggests that a non-invasive low-cost exam such as HBS may be a promising tool to predict PHLF not only in neoplastic patients but also to evaluate potential living donors. Larger studies are needed to draw any conclusion regarding the benefits of HBS in the living liver donor workup.

Liver metastases from prostate cancer at 11C-Choline PET/CT: a multicenter, retrospective analysis.

AIM: During our daily clinical practice using 11C-Choline PET/CT for restaging patients affected by relapsing prostate cancer (rPCa) we noticed an unusual but significant occurrence of hypodense hepatic lesions with a different tracer uptake. Thus, we decided to evaluate the possible correlation between rPCa and these lesions as possible hepatic metastases. MATERIALS AND METHODS: We retrospectively enrolled 542 patients diagnosed with rPCa in biochemical relapse after a radical treatment (surgery and/or radiotherapy). Among these, patients with a second tumor or other benign hepatic diseases were excluded. All patients underwent 11C-Choline PET/CT during the standard restaging workup of their disease. We analyzed CT images to evaluate the presence of hypodense lesions and PET images to identify the relative tracer uptake. In accordance to the subsequent oncological history, five clinical scenarios were recognized [Table 1]: normal low dose CT (ldCT) and normal tracer distribution (Group A); evidence of previously unknown hepatic round hypodense areas at ldCT with normal rim uptake (Group B); evidence of previously known hepatic round hypodense areas at ldCT stable over time and with normal rim uptake (Group C); evidence of previously known hepatic round hypodense areas at ldCT, in a previous PET/CT scan, with or without rim uptake and significantly changing over time in terms of size and/or uptake (Group D); evidence of hepatic round hypodense areas at ldCT with or without rim uptake confirmed as prostate liver metastases by histopathology, triple phase ceCT, ce-ultra sound (CEUS) and clinical/biochemical evaluation (Group E). We evaluated the correlation with PSA level at time of scan, rim SUVmax and association with local relapse or non-hepatic metastases (lymph nodes, bone, other parenchyma). RESULTS: Five hundred and forty-two consecutive patients were retrospectively enrolled. In 140 of the 542 patients more than one 11C-choline PET/CT had been performed. A total of 742 11C-Choline PET/CT scans were analyzed. Of the 542 patients enrolled, 456 (84.1%) had a normal appearance of the liver both at ldCT and PET (Group A). 19/542 (3,5%) belonged to Group B, 13/542 (2.4%) to Group C, 37/542 (6.8%) to Group D and 18/542 (3.3%) to Group E. Mean SUVmax of the rim was: 4.5 for Group B; 4.2 for Group C; 4.8 for Group D; 5.9 for Group E. Mean PSA level was 5.27 for Group A, 7.9 for Group B, 10.04 for Group C, 10.01 for Group D, 9.36 for Group E. Presence of positive findings at 11C-Choline PET/CT in any further anatomical area (local relapse, lymph node, bone, other extra hepatic sites) correlated with an higher PSA (p = 0.0285). In both the univariate and multivariate binary logistic regression analyses. PSA, SUVmax of the rim, local relapse, positive nodes were not associated to liver mets (Groups D-E) (p > 0.05). On the contrary, a significant correlation was found between the presence of liver metG (group D-E) and bone lesions (p= 0.00193). CONCLUSION: Our results indicate that liver metastases in relapsing prostate cancer may occur frequently. The real incidence evaluation needs more investigations. In this case and despite technical limitations, Choline PET/CT shows alterations of tracer distribution within the liver that could eventually be mistaken for simple cysts but can be suspected when associated to high trigger PSA, concomitant bone lesions or modification over time. In this clinical setting an accurate analysis of liver tracer distribution (increased or decreased uptake) by the nuclear medicine physician is, therefore, mandatory.

Serum and exhaled breath condensate leptin levels in asthmatic and obesity children: a pilot study.

BACKGROUND: Recent studies have highlighted the possible involvement of leptin in inflammation. The leptin receptor is also expressed by alveolar macrophages, T lymphocytes and bronchial epitelial cells, suggesting a possible role in the cascade of airway inflammation. OBJECTIVES: The aim of the study was to evaluate the levels of leptin in exhaled breath condensate (EBC) from asthmatic, normal- and overweight children, in relationship with airway inflammation. METHODS: 15 asthmatic non-obese children, 15 healthy non-asthmatic non-obese children, 11 obese children with asthma (OA) and 20 obese children without asthma (ONA) were enrolled. Body impedance of body weight, EBC collection, FeNO, spirometry and a blood sampling for serum leptin were assessed. RESULTS: Leptin EBC levels were significantly higher (3.9 ng ml-1 ± 1.3) in overweight children than those obese with asthma (3.6 ng ml-1 ± 1.6; p = 0.97), non-owerweight asthmatics (2.2 ng ml-1 ± 1.2; p < 0.0001) and in healthy children (0.9 ng ml-1 ± 0.6; p < 0.001). Leptin EBC levels in asthmatic children were significantly higher than in healthy children (p = 0.05). Leptin serum levels were significantly higher in the overweight children compared with the asthmatics (12.7 ng ml-1 ± 13.2; p < 0.001) and the healthy group (11.1 ng ml-1 ± 11.2; p < 0.001). We observed a significant correlation between EBC-leptin levels and the serum-leptin levels (p = 0.001). No correlations were found between EBC-leptin levels, FeNO and lung function. CONCLUSIONS: This study shows that leptin is measurable in EBC in children and that EBC-leptin levels are significantly higher in the obese subjects and in asthmatic ones compared with healthy subjects. Leptin may therefore represent a non-invasive marker of non-specific airway inflammation in children.

Interpretation of 11C-choline PET/CT for the diagnosis of local relapse in radically treated prostate cancer.

PURPOSE: 11C-choline PET/CT is a widely-used tool for the diagnostic of prostate cancer (PCa). In literature, a great variability of local relapse (LR) detection rate is reported. The aim of this study is to provide positivity criteria for 11C-choline PET/CT detection of LR in patients who had surgery for PCa and presented prostate specific antigen (PSA) failure. METHODS: Sixty patients radically treated for PCa and presenting PSA failure were retrospectively analysed. Two Nuclear Medicine Physicians revised the 11C-choline PET/CT scans and defined by consensus if even mild focal uptake was present in the prostate bed (PB) and bladder-urethral junction (BUJ) along midline, regardless the previous report results.The results were subsequently correlated with a clinical and radiological follow up (FU) of 1 to 2 year and with TNM staging, Gleason score (GS), PSA level at relapse, radiotherapy (RT) and hormone therapy (HT) after surgery. RESULTS: There was focal uptake in 22/60 patients; 11 of them were true positive and 11 false positive. The PSA level showed a tight connection with the true positivity/negativity of Choline scan. Most of true positive cases (10/11 patients) presented a PSA ≥ 1 ng/ml, while approximately half of the false positive cases (5/11 patients) presented PSA below 1 ng/ml. The other variables were not correlated to Choline detection rate for LR. CONCLUSIONS: This study shows that an even mild focal uptake of Choline in the PB and BUJ along midline must be considered suspicious for LR in patients radically treated for PCa, especially if they are presenting with PSA level > 1 ng/ml.

Ambroxol inhibits neutrophil respiratory burst activated by alpha chain integrin adhesion.

The purpose of the present study was to investigate the possible anti-oxidant effect(s) of Ambroxol on neutrophils activated by ligand-binding of the drug with membrane-associated adhesion integrin CD11a and to estimate dose-response changes in oxygen free radical production. The amount of free radical production by anti-CD11a- and anti-CD4-coated neutrophils stimulated with N-formyl-methionyl-leucyl-phenylalanine (FMLP) and challenged with increasing concentration of Ambroxol, was evaluated within a time frame of 90 minutes. A significant dose-dependent effect response of Ambroxol on O2‾ production by cells coated with anti-CD11a antibody was observed. This preliminary study opens a new perspective on the therapeutic role of Ambroxol as an antioxidant drug and for its potential use in controlling oxidative stress, particularly in leukocyte-dependent inflammation.

Gallium-68 DOTANOC imaging in paraganglioma/pheochromocytoma: presentation of sample cases and review of the literature.

Gallium-68 DOTANOC is a high affinity somatostatin receptor ligand, first introduced in 2005 for imaging neuroendocrine tumors. Due to its technically simple production, broad availability, favourable biodistribution and advantageous dosimetry, although not approved yet in all European countries, gallium-68 DOTANOC has rapidly gained acceptance in the diagnostic and therapeutic work-flow of different types of neuroendocrine tumors. Principal indications in clinical practice in countries where it is officially approved include diagnosis and staging, restaging after treatment, identification of sites of unknown primary and selection of patients with neuroendocrine tumors eligible for therapy with somatostatin analogues.

Use of PET/CT to evaluate response to therapy in lymphoma.

(18)F-FDG-PET is a well established standard procedure for most lymphoma subtypes. In particular the advantage of metabolic imaging stands in its strong predictivity in response. Indeed PET scan has been incorporated into revised response criteria for aggressive lymphomas and recommended to be performed at baseline and after therapy. At the same time, several ongoing clinical trials are investigating the value of treatment adaptation based on interim PET (PETi) results for Hodgkin Lymphoma (HL) and aggressive Non-Hodgkin Lymphoma (NHL). On the other hand, scientific literature provides limited detailed information regarding the numerous non aggressive NHL subtypes. Usually indolent NHL are typically less FDG avid, furthermore their long natural history and high incidence of recurrence decreases the clinical impact of a potential risk-adapted or response-adapted approach. We reviewed, from a nuclear medicine point of view and a clinical point of interest, evidence for the use of FDG-PET in monitoring early and end treatment response.

Myocardial ischemia induced by nebulized fenoterol for severe childhood asthma.

We examined for myocardial ischemia induced by continuous inhalation of fenoterol in children with severe acute asthma. Thirty children with severe acute asthma were evaluated for signs of myocardial ischemia when treated with 0.5 mg kg dose (maximum 15 mg) of inhaled fenoterol for one hour. The heart rate was measured before and after inhalation. Cardiac enzymes (creatine kinase, creatine kinase MB fraction and troponin levels) were measured at admission and 12 hours later. An EKG was recorded before inhalation was started and immediately after its completion to detect the presence of any evidence of myocardial ischemia. All patients developed significant increase in heart rate. Six patients showed EKG changes compatible with myocardial ischemia, despite normal enzyme levels. Patients with severe acute asthma show tachycardia and may show EKG changes of myocardial ischemia.

Tumor necrosis factor-alfa production by monocytes from lung and colorectal cancer patients.

Tumour necrosis factor-alpha (TNF-alpha) is a monocyte (MO)-derived cytokine that plays an essential role in the immunological system. In the present study our aim was to evaluate the levels of TNF-alpha secreted by MO from cancer patients. Blood MO were obtained from 10 lung cancer patients (LCP), 10 colorectal cancer patients (CCP) and 10 healthy donors (HD). TNF-alpha levels in MO culture supernatants spontaneously (sp) secreted or after stimulation with LPS treatment were evaluated using a commercial ELISA kit (sensibility: 10-1000 pg/ml). Mean values, expressed as pg/ml were: LCP: sp= 452.6+/-107.2, LPS= 589.5+/-126.7); CCP: sp= 84.1+/-25.0, LPS= 437.3+/-93.2; HD: sp= 74.2+/-21.5, LPS= 573.5+/-87.1. We concluded that MO from LCP secrete high levels of TNF-alpha spontaneously (p< 0.003 versus HD) and it was also observed an absence of response to LPS treatment in the 33% of the cases in these patients.

Behaviour of human lymphocytic isoenzymes of 5'-nucleotidase.

The behaviour of 5'-nucleotidase isoenzymes (ecto-5'-nucleotidase, e-Ns and c-N-II soluble 5'-nucleotidases) was studied in lymphocytes from patients with B-cell chronic lymphocytic leukemia. A strong reduction in ecto- and soluble activities was observed, although the pattern of the three 5'-nucleotidases did not always strictly overlap. A significant decrease (p<0.05) in ecto-5'-nucleotidase, e-Ns and c-N-II was found in B and T populations (B lymphocytes: 1.13, 0.88 and 1.26 nmol/h/10(6) cells versus 95.96, 9.64 and 13.73 nmol/h/10(6) cells in controls; T lymphocytes: 1.31, 0.23 and 0.06 nmol/h/10(6) cells versus 9.25, 1.31 and 2.10 nmol/h/10(6) cells in healthy subjects). The percentage of ecto-5'-nucleotidase-positive cells (CD73+) was reduced in leukemia patients, indicating a lower number of active molecules on the cell surface. The results of RT-PCR analysis showed that the ecto-5'-nucleotidase mRNA of leukemia patients was not defective.

5'-nucleotidase activity in lymphocytes from patients affected by B-cell chronic lymphocytic leukemia.

OBJECTIVES: The activity of membrane-bound ecto-5'-nucleotidase and soluble e-Ns and c-N-II 5'-nucleotidases was evaluated on lymphocytes from patients affected by B-cell chronic lymphocytic leukemia (B-CLL). A statistically significative decrease in ecto-5'-nucleotidase, e-Ns, and c-N-II activities was observed in peripheral blood lymphocytes and in B and T populations from affected individuals. DESIGN AND METHODS: For the assay of ecto-5'-nucleotidase, e-Ns, and c-N-II activity we used a radioactive procedure coupled to HPLC. Since the ecto-5'-nucleotidase is identified as CD73 antigen, we performed immunofluorescence analysis using a specific monoclonal antibody. We analyzed ecto-5'-nucleotidase mRNA by RT-PCR to ascertain the possibility of an alteration in the transcription of its gene. RESULTS: A decrease in ecto-5'-nucleotidase activity was correlated to reduction in ecto-5'-nucleotidase positive cells (CD73+) in leukemia patients. RT-PCR produced a fragment of the expected size and the specific mRNA was found expressed in both healthy subjects and leukemia patients. CONCLUSIONS: The decrease in ecto-5'-nucleotidase activity in patients with B-CLL is not due to loss of transcription of the specific mRNA. The presence of point mutations, splicing alteration, or posttranslational modifications must be investigated. If a defect at DNA or RNA level will be detected, the molecular analysis will be considered for diagnosis of B-cell chronic lymphocytic leukemia.

Intracytoplasmatic and extracellular interleukin-1 production by monocytes of lung and colorectal cancer patients.

We studied the production of interleukin-1 (IL-1) by peripheral blood monocytes (Mo) from twelve normal subjects (NS) and eight and nine untreated lung and colorectal cancer patients (CP), respectively. No significant changes of extracellular IL-1 biological activity was observed between CP and NS by thymocyte proliferation assay. This result was independent that the cells were treated or not with lipopolisaccharide from E. coli (LPS, 10 micrograms/ml). Moreover, CP present normal amount of antigenic IL-1 beta in LPS treated Mo culture supernatants by enzyme-linked immunosorbent assay (ELISA). The biological activity of IL-1 released was not significant modified after indomethacin (Indo, 10(-6)M) and LPS + Indo treatments. Furthermore, patients showed a low percentage of LPS activated Mo with intracytoplasmatic IL-1 (alpha + beta) compared to normal values. These results were obtained by immuno-alkaline phosphatase staining using monoclonal antibody anti IL-1 (alpha + beta). In conclusion, CP had a reduced number of Mo with intracytoplasmatic IL-1 (alpha + beta) and the difference observed may depend on degradation or in the rate of synthesis of this cytokine.

Clavin, a type-1 ribosome-inactivating protein from Aspergillus clavatus IFO 8605. cDNA isolation, heterologous expression, biochemical and biological characterization of the recombinant protein.

We describe the cloning and expression of a new cDNA from the filamentous fungus Aspergillus clavatus IFO 8605. This cDNA contains an open reading frame (ORF) that predicts a putative ribonuclease precursor with high similarity to the alpha-sarcin family of ribosome-inactivating proteins (RIPs). The cDNA encoding the mature protein was expressed in Escherichia coli, and the recombinant protein, a 17-kDa polypeptide designated clavin was purified and characterized. Clavin shows typical type-1 RIP properties: specific cleavage of ribosomal and synthetic RNA and inhibition of protein synthesis in cell-free and cellular systems. When selectively targeted to a tumour cell antigen by coupling to a monoclonal antibody (mAb) clavin was able to inhibit protein synthesis at nanomolar concentration. Pharmacokinetics analysis in mice indicated an elimination half-life (t1/2 beta) of 7.4 h with no particular accumulation in major organs. Liver toxicity was very limited and transient while no alteration of kidney function was observed. Clavin induced a late and very low antibody response in mice. The in vitro and in vivo biological characteristics of clavin, together with its availability in large amounts, suggest the usefulness of this toxin in the production of toxic chemical conjugates.

[Prevention of postoperative nausea and vomiting with ondansetron: a prospective, randomized, double-blind study in 90 patients]. / Profilassi della nausea e del vomito postoperatori con ondansetron: studio prospettico e randomizzato, condotto in doppio cieco, su 90 pazienti.

Postoperative nausea and vomiting (PONV) are among the most common complications in surgical patients. In this prospective, double blind, parallel group study we compare the prophylactic antiemetic efficacy of ondansetron versus placebo in 90 patients undergoing general balanced anaesthesia. The patients were stratified according to the kind of surgery and randomly allocated to three treatment groups: 30 patients (Group A) received ondansetron 4 mg i.v. 1 hour before the induction of anaesthesia and placebo 1 hour before the end of surgery; 30 patients (Group B) received placebo 1 hour before the end of anaesthesia and ondansetron 4 mg i.v. 1 hour before the end of surgery; 30 patients (Group C-control group) received placebo in both the administrations. Data were analyzed by Student t test and chi 2 test; significance was taken at p < 0.05. The three groups proved comparable with respect to demographic characteristics, duration of anaesthesia and fentanyl consumption. Analysis of the results showed that PONV had a significantly lower incidence in treated patients (Groups A and B) than in the control group patients (Group C): postoperative nausea occurred in 13%, 30% and 67% of patients in Group A, B and C respectively and it was associated with vomiting in 3%, 7% and 57% of patients in Group A, B and C respectively. Although the patients in Group A showed a lower incidence of PONV in comparison to the patients in Group B, such differences proved to be not statistically significant. No adverse effects in relation to drug administration were observed. We conclude that ondansetron 4 mg i.v. is safe and effective in preventing PONV in the surgical patients, particularly when administered before the induction of anaesthesia.

[The pre-emptive analgesia in the treatment of postoperative pain]. / La pre-emptive analgesia nel trattamento del dolore post-operatorio.

The term "pre-emptive analgesia" implies the hypothesis that an analgesic treatment, given before nociceptive stimuli reach the Central Nervous System, could prevent or reduce the subsequent pain. The rational basis of this phenomenon, giving rise to much interest in the last years, comes from the finding that noxious stimuli cause wind-up and receptive fields expansion phenomena in the dorsal horn neurons of the spinal cord leading to hyperalgesia. Recently, many clinical trials to verify the existence of a pre-emptive effect regarding the management of postoperative pain by the administration of non steroidal antiinflammatory drugs (NSAIDs), local anesthetics and opioids have been conducted. As regards NSAIDs to date no study demonstrated a pre-emptive effect. Conflicting results emerged from trials employing local anesthetics, opioids or associations of the three classes of drugs. Thus, the "pre-emptive analgesia" represents a very important phenomenon for the basic research, but further trials must investigate its clinical impact.

[Intravenous patient-controlled analgesia (PCA) in the treatment of postoperative pain: rationale and clinical application]. / Patient-Controlled Analgesia (PCA) endovenosa nel trattamento del dolore post-operatorio: razionale ed applicazione clinica.

The clinical use of the patient-controlled analgesia (PCA) represents a further improvement in the treatment of post-operative pain. In this way in success due to inadequate protocols, unpredictability of the drug absorption and variability of the response to one drug or to the same pain patterns between patients can be avoided. This technique allows the patient himself to control the pain without depending upon nurses or physicians for the administration of analgesic drugs. Although the PCA is in use since several years, there are still some unresolved problems which are considered in this paper.

Isolation of rsp-1, a novel cDNA capable of suppressing v-Ras transformation.

Using an expression cloning assay, we have isolated a novel cDNA, referred to as rsp-1, which suppresses the v-Ras-transformed phenotype. When introduced into NIH 3T3 fibroblasts under the control of a metallothionein promoter, rsp-1 confers resistance to v-Ras, but not to v-Mos or v-Src, and inhibits growth of the cells. The rsp-1 cDNA contains a 831-bp open reading frame encoding a 277-amino-acid leucine-rich protein. The rsp-1 cDNA exhibits no significant homology to sequences in the DNA data bases. However, searches of the protein data bases revealed that it contains a series of leucine-based repeats which are homologous to the leucine repeats found in the regulatory region of the yeast adenylyl cyclase. rsp-1 specific RNA is detectable in a wide variety of cell lines and tissues, and the gene is conserved among eukaryotic species. These data suggest that rsp-1 plays a role in Ras signal transduction.

Natural human antibodies to gamma interferon interfere with the immunomodulating activity of the lymphokine.

Natural antibodies to gamma interferon (IFN-gamma) were found in patients suffering from different viral diseases and, at a lower titer, in healthy individuals. Such antibodies were affinity-purified and studied for their capability to interfere in vitro with the antiviral and immunomodulating activity of IFN-gamma. Data obtained show that these human anti-IFN-gamma antibodies have no inhibitory effect on the antiviral activity of IFN-gamma. On the contrary, they are able to inhibit the expression of Fc receptor sites and HLA-DR antigens induced by IFN-gamma on the U-937 cells, a human monocytoid/macrophage-derived cell line. These antibodies can also interfere in a mixed lymphocyte culture (MLC) with the proliferation of lymphocytes and the generation of cytotoxic lymphocytes. However, they showed only a moderate inhibitory effect on the cytotoxicity generated in MLC to K-562 cells. Human antibodies capable of interfering with the immunomodulating activities of IFN-gamma might open up a new field in clinical therapy for those diseases that carry evidence of activated cell-mediated immunity.

Amiloride inhibits protein synthesis and lowers the intracellular pH in exponential growing Yoshida rat ascites hepatoma (AH 130) cells: evidence for a role of the Na+/H+ exchanger.

We have previously demonstrated in a rat ascites hepatoma cell line (Yoshida AH 130) the presence of a glucose-activatable and amiloride sensitive Na+/H+ exchange (Cell Biol. Int. Rep., 1984, 8, 297-307). Amiloride is known to inhibit this exchange and to cause a cytoplasmic acidification, with inhibition of protein and DNA synthesis, in cells induced to grow. Amiloride appears also to penetrate the cells and to inhibit directly protein synthesis. In the present report we describe experiments in which the activity of amiloride (0.1, 0.4 and 3.0 mM) on protein synthesis and the internal pH of cells was compared in exponential growing and stationary phase Yoshida ascites cells. In phosphate buffered medium and Na+ out = 147 mM no inhibition of protein synthesis (3H-leu incorporation into total cell protein) and no internal acidification (14C-DMO distribution between intra- and extracellular volume) were produced by 0.1 and 0.4 mM amiloride in exponential growing cells. In stationary phase cells, on the contrary, 0.4 mM amiloride inhibited protein synthesis by 60% without decreasing the internal pH. When the Na+ out was lowered to 25 mM, to reduce competition with amiloride, and/or all Na+ out was substituted with choline, 0.1 and 0.4 mM amiloride markedly inhibited protein synthesis and decreased the internal pH in exponential growing cells. No apparent inhibition occurred in stationary phase cells under the same conditions, possibly due to a preexistent internal acidification, with severe decrease of protein synthesis. Fluorimetric studies of amiloride "binding" to ascites cells showed that a reduced number of amiloride receptor sites could exist in Yoshida hepatoma cells at the stationary phase of growth.(ABSTRACT TRUNCATED AT 250 WORDS)