Quantitative analysis of myocardial blood flow in surgically revascularized and not revascularized myocardial segments. A pilot PET study

PURPOSE

To prospectively compare changes in myocardial blood flow (MBF) and myocardial flow reserve (MFR) in multivessel coronary artery disease (MVCAD) patients undergoing incomplete revascularization (IR) versus complete revascularization (CR) by coronary artery bypass grafting (CABG).

METHODS

Seven male patients (age 68 ± 9 years) with MVCAD underwent myocardial perfusion PET/CT with [13N]ammonia before and at least 4 months after CABG. Segmental resting and stress MBF as well as MFR were measured. Resting and during stress left ventricle ejection fraction (LVEF) were also calculated.

RESULTS

Three patients (43%) underwent CR and four (57%) IR. Among 119 myocardial segments, 101 (85%) were revascularized, and 18 (15%) were not. After CABG, stress MBF (mL/min/gr) and MFR are significantly increased in all myocardial segments, with a greater increase in the revascularized segments (p = 0.013). In both groups, LVEF significantly decreased during stress at baseline PET (p = 0.04), but not after CABG.

CONCLUSION

Stress MBF and MFR significantly improve after CABG in both revascularized and not directly revascularized myocardial segments. IR strategy may be considered in patients with high surgical risk for CR.

Hypercalcemic crisis in third trimenon: evaluating the optimal treatment strategy

Hypercalcemia due to primary hyperparathyroidism during pregnancy is a rare condition and associated with increased morbidity and mortality for the mother and the unborn child. Whereas parathyroidectomy is favored during the second trimester, no clear recommendations exist for its management during the third trimenon. We here report the case of a 26-year-old woman in the 29th week of her first pregnancy, who was admitted to our clinic with hypertension, intra-uterine growth retardation and polyhydramnios. Severe hypercalcemia due to primary hyperparathyroidism was diagnosed (total calcium 3.34 mmol/l; PTH 216 pg/ml), but no enlarged parathyroid gland could be localized by ultrasound. Treatment with calcitonin and cinacalcet could not control hypercalcemia. Therefore explorative surgery was performed and a single parathyroid adenoma was resected, resulting in normalization of serum calcium levels. The surgical procedure was tolerated well by the mother and fetus. Hypercalcemia-induced hypertension and polyhydramnios ameliorated before C-section was performed two weeks later and unrelated to the intervention. This case report underlines the importance of early diagnosis and treatment of primary hyperparathyroidism during pregnancy. If diagnosed in the third trimenon, an interdisciplinary approach is crucial. If medical treatment fails to sufficiently control hypercalcemia, surgical parathyroid exploration should be considered even in cases of unsuccessful localization of adenomatous parathyroid glands.

Feasibility, safety, and preliminary proof of principles of autologous neural stem cell treatment combined with T-cell vaccination for ALS patients

Uncontrolled activation of the innate immune system promotes the deterioration of neurons in different neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). T-cell vaccination (TCV) was developed by Irun Cohen and coworkers at the Weizmann Institute of Science (Israel) during the late 1970s and has been demonstrated to be an effective treatment for human autoimmune diseases and a regulator of macrophage activation in animal models. We treated seven ALS patients with this cell therapy and were able to slow or stop disease progression in the affected individuals. The median survival, which is 3.5 years, was extended to 6 years. They were also treated with autologous adult neural stem cells associated with effector T cells. The observed neurologic improvements after treatment lasted for at least 1 year. Clinical recovery in the treated ALS patients was confirmed by an independent, skilled neurologist using the ALS Functional Rating Scale-Revised (ALSFRS-R). TCV in conjunction with an autologous neural stem cell treatment might be a feasible, minimally invasive, safe, and effective approach to obtain enduring therapeutic effects in ALS patients.

Tumor-associated stroma cell therapy in patients with pancreatic cancer potentiates therapeutic effect of tumor B-cell hybrid (TBH) auto-vaccines

4569

Background: Pancreatic Cancer (PC) tumor-associated stroma cells play an important role in PC’s immune surveillance escape. Secretion of Transforming Growth Factor β (TGFβ) and IL10 by PC tumor cells disturb the antigen presenting function of the stroma cells. It may explain the poor results of most immunotherapeutic approaches. Granger et al. reported a successful approach for treating small size pancreatic tumors, namely Mixed Lymphocyte Culture (MLC) cytoimplant. MLC cytoimplants, acting as a Th1 cytokine pump inside the tumor, are thought to revert the tumor-associated stroma cell dysfunction, and facilitate an immune attack. In view that TBH auto-vaccines have modest activity in advanced PC, we considered the possibility that a combination of MLC cytoimplant and TBH vaccines might potentiate the immune response. In this study we compared the response of MLC cytoimplant, TBH vaccines, and combinations of both therapies. Methods: 40 patients with advanced PC were treated: Group 1 MLC cytoimplan (10); Group 2 TBH vaccines (3); Group 3 one MLC cytoimplant and three TBH vaccines (9); Group 4 one MLC cytoimplant and six TBH vaccines (12) and Group 5 one MLC cytoimplant followed by two TBH immunizations, then second MLC cytoimplant followed by 4 TBH vaccines (6). Anti-tumor immune response was measured by Lymphocyte proliferation assay against autologous PC. Results: MLC cytoimplant combined with TBH vaccines appears to have synergistic and effective anti-tumor activity in advanced PC. Kaplan Meyer analysis showed a significant difference in the survival of group 4 as compared with the other four groups (P<0.001). After cytoimplant administration, 1/12 patients in Group 4 and 1/6 patients in Group 5 experienced transient bleeding episodes (lasting less than 12 hours). After the second MLC cytoimplant, all patients in Group 5 developed significant Graft Vs Host Disease (GVHD), an occurrence that probably contributed to the Group’s shorter survival when compared to Group 4’s survival. Conclusions: The observation that a second MLC cytoimplant leads to GVHD is consistent with a pro-inflammatory change in the tumor-associated stroma cells. MLC cytoimplant followed by TBH vaccines appear to prolong survival.

No significant financial relationships to disclose.

Combined protocol of cell therapy for chronic spinal cord injury. Report on the electrical and functional recovery of two patients

BACKGROUND

This is a preliminary report on successful results obtained during treatment of two patients with chronic spinal cord injury. The therapeutic approach was based on the generation of controlled inflammatory activity at the injury site that induced a microenvironment for the subsequent administration of autologous, BM-driven transdifferentiated neural stem cells (NSC).

METHODS

BM mesenchymal stem cells (MSC) were cocultured with the patient's autoimmune T (AT) cells to be transdifferentiated into NSC. Forty-eight hours prior to NSC implant, patients received an i.v. infusion of 5 x 10(8) to 1 x 10(9) AT cells. NSC were infused via a feeding artery of the lesion site. Safety evaluations were performed everyday, from the day of the first infusion until 96 h after the second infusion. After treatment, patients started a Vojta and Bobath neurorehabilitation program.

RESULTS

At present two patients have been treated. Patient 1 was a 19-year-old man who presented paraplegia at the eight thoracic vertebra (T8) with his sensitive level corresponding to his sixth thoracic metamere (T6). He received two AT-NSC treatments and neurorehabilitation for 6 months. At present his motor level corresponds to his first sacral metamere (S1) and his sensitive level to the fourth sacral metamere (S4). Patient 2 was a 21-year-old woman who had a lesion that extended from her third to her fifth cervical vertebrae (C3-C5). Prior to her first therapeutic cycle she had severe quadriplegia and her sensitive level corresponded to her second cervical metamere (C2). After 3 months of treatment her motor and sensitive levels reached her first and second thoracic metameres (T1-T2). No adverse events were detected in either patient.

DISCUSSION

The preliminary results lead us to think that this minimally invasive approach, which has minor adverse events, is effective for the repair of chronic spinal cord lesions.

Tumor stem cell vaccine for NSCLC and GBM-assessment of feasibility, adverse events and efficacy

2556

Background: Only a small part of the total cell population of a malignancy has the potential to grow and regenerate the total tumor mass. The rest are only differentiated forms of those stem cells. This biologic characteristic seems to be responsible for the failure to achieve long term remission for several peptide based vaccines. Method: To overcome this obstacle, we have established a technique that uses tumor stem cells (TSC) to develop a TSC-B cell vaccine. To test efficacy and best administration form of this vaccine, we have proceeded as follow: First: Pieces from total or partial resections of GBM or NSCLC were mechanically dissociated to a single cell suspension. Cells were cultured in an appropriate tissue culture medium and allowed to grow for two weeks or until they reach a semi confluent stage. Then, cells were harvested and re-seeded. This procedure was repeated 6 to 24 weeks according to vitality and growth characteristics of cells. Finally, Tumor cells were fused with autologous B cells. The hybrid was kept in culture and used for an intra lymph node immunization every 3 weeks. To potentiate its action, 3 days prior to its administration we co-incubated the hybrid with either autologous dendritic cells or autologous mononuclear cells. Adverse events were evaluated by the “Common terminology criteria for Adverse Events (AE), 2004” developed by NIH. Definitions are available on the web at http://ctep.cancer.gov/reporting/ctc.html . Clinical efficacy of this procedure was evaluated according RESIST criteria for NSCLC and a combination of MRI and spectroscopy for GBM. Results: At present 8 patients with GBM with post surgical second relapse and who had received complete radiotherapy doses were treated. We have also treated 6 patients with NSCLC:4 with minimal residual disease and 2 with measurable residual disease. Patients have presented minor adverse events, mainly referred to inflammation of the injection site. The median survival rates registered to the present are 22 months for GBM patients and 3 years for patients with stage IV NSCLC who had minimal residual disease at the beginning of the treatment. Conclusion: A tumor stem cell vaccine seems to be a feasible and effective therapy with very low toxicity for the treatment of advanced GBM and NSCLC patients.

No significant financial relationships to disclose.

Skeletal muscle mitochondrial free-fatty-acid content and membrane potential sensitivity in different thyroid states: involvement of uncoupling protein-3 and adenine nucleotide translocase

The effect of triiodothyronine (T3) on mitochondrial efficiency could be related to an increase in the concentrations of some proteins, such as uncoupling proteins (UCPs). Free fatty acids (FFA) seem to be a cofactor essential for the uncoupling activity of UCP3. In this paper, we report that the hypothyroidism-hyperthyroidism transition is accompanied by increases: (i) in the endogenous levels of mitochondrial FFA and (ii) in the sensitivity to FFA shown by the mitochondrial respiration rate and membrane potential, which correlated with the level of UCP3 protein. The level of the mRNA for adenine-nucleotide translocase-1 (ANT) was not affected by the thyroid state, while the ANT contribution to FFA-induced changes in mitochondrial uncoupling was low in the hypothyroid and euthyroid states but became more relevant in the hyperthyroid state at the highest concentration of FFA.

Effect of lercanidipine and its (R)-enantiomer on atherosclerotic lesions induced in hypercholesterolemic rabbits

The in vivo antiatherogenic activity of the calcium antagonist lercanidipine and its (R)-enantiomer was investigated in two different types of atherosclerotic lesions (hyperplastic and fatty-streak lesions) in rabbits. Lercanidipine (0.3, 1, and 3 mg kg(-1) week(-1)) as well as its (R)-enantiomer at 3 mg kg(-1) week(-1) were given by subcutaneous injection for 10 weeks to White New Zealand rabbits, with cholesterol feeding beginning at week 2. The hyperplastic lesion was obtained by positioning a hollow silastic collar around one carotid artery, while aortic fatty streak lesions were induced by cholesterol feeding. In untreated animals (n=5), 14 days after collar positioning an intimal hyperplasia was clearly detectable: the arteries without collar showed a intima/media (I/M) ratio of 0.03+/-0.02, whereas in carotids with a collar the ratio was 2+/-0.42. In lercanidipine-treated animals a significant and dose-dependent effect on intimal hyperplasia was observed. I/M ratios were 0.73+/-0.4, 0.42+/-0.1, 0.32+/-0.1 for 0.3, 1, and 3 mg kg(-1) week(-1), respectively (P<0.05). The lercanidipine enantiomer (3 mg kg(-1) week(-1)) was as effective as the racemate (0.41+/-0.11). Proliferation of smooth muscle cells, assessed by incorporation of BrdU into DNA, was reduced by about 50%, 70%, 85%, and 80% by lercanidipine (0.3, 1, and 3 mg kg(-1) week(-1)) and its (R)-enantiomer, respectively. The area of fatty-streaks in the aorta (n = 11-15) was significantly reduced by lercanidipine (3 mg kg(-1) week(-1), 16% vs 27%, P<0.05), a trend was observed also with lower doses. When different segments of the aorta were considered (arch, thoracic, abdominal) a significant and dose-dependent effect in the thoracic and abdominal aorta was observed also at lower doses. The (R)-enantiomer was as effective as lercanidipine. These results suggest a direct antiatherosclerotic effect of lercanidipine, independent of modulation of risk factors such as hypercholesterolemia and/or hypertension as demonstrated by the absence of stereoselectivity.

[Neuropsychologic effects of anesthesia in the elderly]

Two anaesthetic techniques, the general balanced anaesthesia and the spinal one, have been compared in relation to their effects on neuropsychological functions as assessed by a neuropsychological test battery. Seventeen patients, who underwent different kinds of operations, have been kept under observation and checked up from a neuropsychological point of view 3 days before (time A) and 7 and 30 days after the operation (respectively time B and time C). No statistical significant differences in relation to the two anaesthetic techniques were found when comparing A, B and C assessment times. A decrease in cognitive performance at time B and a gradual return to basal condition were observed in patients who underwent general anaesthesia. Nevertheless the lack of statistical significance of the observed data leads to the need for further investigation.

Mass spectrometric identification of urinary and plasma metabolites of 2-(6'-carboxyhexyl)-3-n-hexylcyclohexylamine, a new antiaggregating agent

The compound IBI-P-05006, 2-(6'-carboxyhexyl)-3-n-hexylcyclohexylamine, is an antiaggregating agent under development. IBI-P-05006 is an in vitro inhibitor of platelet aggregation. The biotransformation of this compound has been studied in the dog and rat. We present here a study on the metabolites of IBI-P-05006 found in dog and rat urine, and in dog plasma. Analyses were done by gas chromatography-mass spectrometry. In dog urine 15 metabolites were identified. Some of them were also found in dog plasma and in rat urine. The unmetabolized drug was found only in plasma. 10 different hydroxylated metabolites were characterized. The hydroxyl groups were introduced in the hexyl chain in positions omega-4, omega-3, omega-2, omega-1 and omega.

Mass spectrometric identification of urinary and plasma metabolites of 6-(6'-carboxyhexyl)-7-n-hexyl-1,3-diazaspiro-[4-4]-nonan-2,4-dione, a new cytoprotective agent

The compound IBI-P-01028, or R,S-cis-6-(6'-carboxyhexyl)-7-trans-n-hexyl-1,3-diazaspiro-[4-4]-nona n-2,4- dione, is a new cytoprotective agent under development. To study the metabolites of this compound in laboratory animals, we administered it to dogs and rats, and analyzed extracts from dog and rat urine, and from dog plasma, by GC-MS. The metabolic profiles were different in the rat and dog. In the dog (plasma and urine), one metabolite was found, and in the rat urine two other metabolites were found. The unmetabolized drug was found only in the dog plasma and urine.

Metabolism and pharmacokinetics of p-(3,3-dimethyl-1-triazeno) benzoic acid in M5076 sarcoma-bearing mice

The pharmacokinetics of the anticancer agent p-(3,3-dimethyl-1-triazeno) benzoic acid (pCOOH-DMT), a drug now in phase I clinical trial in Europe, was investigated in C57Bl female mice with M5076 reticulum-cell sarcoma that were treated i.v. with 200 mg/kg pCOOH-DMT. The drug disappeared from plasma with a terminal half-life of about 2.5 h. Plasma clearance was approximately 6 ml/min per kg. Distribution studies showed some differences in drug levels in different tissues. The highest levels were found in the tumor, liver, kidney and lung; lower levels were found in the spleen and gut, and the lowest, in the brain. The N-desmethyl derivative of pCOOH-DMT was not detectable in plasma or tissues of mice treated with the drug. Therefore, the previous evidence of low N-demethylation of pCOOH-DMT was confirmed. pCOOH-DMT glucuronide was identified by mass spectrometry and quantified by high-performance liquid chromatography (HPLC) in plasma, tissues and urine samples. pCOOH-DMT glucuronide appears to be the major urinary metabolite of pCOOH-DMT in mice. Another metabolite identified by mass spectrometry and quantified by HPLC in some tissues and urine was pCOOH-DMT glycinate.

New potential immunoenhancing compounds. Synthesis and pharmacological evaluation of new long-chain 2-amido-2-deoxy-D-glucose derivatives

A series of long-chain fatty acids and the corresponding 2-hydroxy, 2-oxo, 3-hydroxy acid glucosamides were evaluated as immunomodulating compounds. In a preliminary screening, 2-[(2-ethoxycarbonyloxy)tetradecanoylamino]-2-deoxy-D-glucos e (2b) and 2-(3-hydroxydodecanoylamino)-2-deoxy-D-glucose (5a) resulted to be the most effective in enhancing the glucosamine activity. The findings of in vitro-ex vivo tests (unidirectional mixed lymphocyte culture reaction and primary antibody production) and in vivo tests (delayed type hypersensitivity, protection against bacterial or fungal infection and against Sarcoma 180 or Lewis lung carcinoma transplants) were very encouraging and allowed to assume for the two substances a protective activity, presumably through the ability of activating phagocytic and NK cells.

Synthesis and in vitro antibacterial activity of a new series of monobactam derivatives

Using as a model monobactams with a substituted alpha-oxyimino moiety in the side chain (aztreonam), a series of 2-(2-aminothiazol-4-yl)-2-hydrazono-acetamido monobactam (II a, f) were prepared by condensation of the hydrazones (I a, e) (Z form) with tetrabutylammonium 3-amino-4-methyl-2-oxo-1-azetidin-sulphonate. Isomerization occurred during this synthesis and gave the E form of all compounds. Monobactams (II a, f) showed no significant in vitro antibacterial activity when compared with aztreonam and with some cephalosporins bearing the same E-hydrazono side chain.

Mass spectrometric identification of urinary and plasma metabolites of 9-hydroxy-19,20-bis-nor-prostanoic acid (rosaprostol)

9-Hydroxy-19,20-bis-nor-prostanoic acid (Rosaprostol) is an antiulcer compound with antisecretory and cytoprotective action. We studied the metabolites of Rosaprostol found in human plasma and in human and rat urine. Sixteen different metabolites were tentatively identified on the basis of their mass spectra. Two presumed metabolites were synthesized. To clarify the identities of some of them, deuterated Rosaprostol was administered to rats and mass spectra of the deuterated and protonated metabolites were examined. Rosaprostol is metabolized following three metabolic pathways leading, combined, to oxidized compounds with a lower number of carbons than the parent drug.

Comparison of metabolism and activity of an aryldimethyltriazene and an aryldiethyltriazene

The antitumoral activity and metabolism of 1-(4-acetylphenyl)-3,3-dimethyltriazene [pAc-(CH3)2] and 1-(4-acetylphenyl)-3,3-diethyltriazene [pAc-(C2H5)2] were studied in mice. pAc-(CH3)2 showed significant antitumoral activity against M5076 ovarian reticular cell sarcoma, L1210 leukemia, EL 4 lymphoma in mice, but not against Lewis lung carcinoma. pAc-(C2H5)2 was inactive in all these murine tumors and was much more toxic than pAc-(CH3)2. pAc-(CH3)2 and pAc-(C2H5)2 were rapidly metabolized in vitro and in vivo to their respective monoalkyltriazenes and to 4-aminoacetophenone (pAc-NH2). In vitro, 79% of the dimethyltriazene was metabolized to its monomethyl analogue, but only 27% of the diethyltriazene was metabolized to the monoethyltriazene. The monoalkytriazenes were almost completely biotransformed to pAc-NH2 by a 9000 g liver fraction. The metabolic pattern in the in vitro study was comparable to that found in vivo.

High-performance liquid chromatographic assay for the determination of p-(3,3-dimethyl-1-triazeno)benzoic acid in mouse plasma

A reproducible and sensitive method is described for assaying p-(3,3-dimethyl-1-triazeno)-benzoic acid (pCOOH-DMT) and for identifying the N-desmethyl metabolite, p-(3-methyl-1-triazeno)benzoic acid (pCOOH-MMT) using high-performance liquid chromatography. The method measures concentrations as low as 1.25 nmol/ml of plasma. Extraction efficiency of internal standard or of added triazenes averages 88% and the coefficient of variation of the method is less than 10%. pCOOH-DMT is stable at room temperature at pH 7.4, whereas pCOOH-MMT undergoes rapid decomposition (half-life 6 min). pCOOH-MMT is more stable in an albumin-containing solution or in plasma, but not in boiled 9000 g mouse liver. After 80 min incubation with a 9000 g mouse liver fraction and reduced nicotinamideadenine dinucleotide phosphate, only 24% pCOOH-DMT was metabolized. Plasma pharmacokinetic studies in mice treated with 200 mg/kg intraperitoneally showed that the potassium salt of pCOOH-DMT has a half-life of 67 min.

Metabolic studies of a podophyllotoxin derivative (VP16) in the isolated perfused liver

The metabolism of VP16 was studied in isolated perfused rat liver. The rate of elimination into the medium and excretion in bile were determined by h.p.l.c. with u.v. detection. With high VP16 concentrations (180 micrograms/ml medium), the elimination half-life of the compound was prolonged markedly (156 v. 45 min for lower doses), the percentage recovered in bile was more than halved and drug accumulation in the hepatic tissue was three times greater. These findings indicate saturation of metabolism and of biliary elimination during high-dose treatment. The presence of glucuronides in the bile of VP16 perfused livers indicates that VP16 undergoes conjugation with glucuronic acid. Formation of picro isomer of VP16 in the liver also occurs.

Pharmacokinetics of teniposide in patients with ovarian cancer

Pharmacokinetics of teniposide (VM26) after each of three doses were investigated by high-performance liquid chromatographic assay in eight patients with ovarian cancer with normal liver and renal functions. Treatment consisted of a first dose of 100 mg/m2 iv as a 1-hour infusion (Day 1), a second dose of 150 mg/m2 iv as a 1-hour infusion (Day 8), and a third dose of 150 mg/m2 as an approximately 1-day infusion (Day 22). Disappearance of VM26 from plasma followed a biexponential decay pattern. The mean terminal half-life (+/- SE) was 6.9 +/- 0.9 hours after the first dose, 6.1 +/- 0.7 hours after the second dose, and 9.7 +/- 1.4 hours after the third dose. VM26 levels in ascites were lower than those in plasma in the first hours after drug administration, but by 24 hours they were similar or slightly higher. Urinary elimination of VM26 as unchanged drug amounted to less than 10% of the dose.

Metabolism of the anticancer agent 1-(4-acetylphenyl)-3,3-dimethyltriazene

High pressure liquid chromatography was used in combination with mass spectrometry to confirm that the main products of in vitro metabolism of 1-(4-acetylphenyl)-3,3-dimethyltriazene are 1-(4-acetylphenyl-3-methyltriazene and 4-aminoacetophenone. In addition a novel metabolite, 1-[4-(1-hydroxyethyl)-phenyl]-3,3-dimethyltriazene, possessing antitumour activity similar to the parent drug, was identified.

Studies of the mode of action of antitumour triazenes and triazines--IV. The metabolism of 1-(4-acetylphenyl)-3,3-dimethyltriazene

The metabolism of 1-(4-acetylphenyl)-3,3-dimethyltriazene has been studied in vivo and in vitro in mice. This dimethyltriazene was extensively metabolised in vivo and HPLC analysis of the plasma revealed the presence of two metabolites, the monomethyltriazene, 1-(4-acetylphenyl)-3-methyltriazene, and the arylamine, 4-aminoacetophenone. The dimethyltriazene was also biotransformed in vitro by a 9000 g fraction of mouse liver homogenate to products which were selectively toxic to TLX5 lymphoma cells. HPLC analysis of the products of in vitro metabolism under these conditions showed the presence of the monomethyltriazene but in an amount insufficient to account for the observed cytotoxicity. The monomethyltriazene was itself rapidly biotransformed by a 9000 g fraction of mouse liver homogenate, and by isolated mouse hepatocytes.

Pharmacokinetics of VP16-213 given by different administration methods

Plasma pharmacokinetics of VP16-213 were investigated after a 30-60 min infusion in 14 adult patients and six children. In adult the elimination half-life (T1/2 beta), plasma clearance (Clp) and volume of distribution (Vd) were respectively 7.05 +/- 0.67 h, 26.8 +1- 2.4 ml/min/m2, and 15.7 +1- 1.8 l/m2; in children 3.37 +/- 0.5 h, 39.34 +1- 6.6 ml/min m2, and 9.97 +/- 3.7 l/m2. After repeated daily doses no accumulation of VP16-213 was found in plasma. The unchanged drug found in the 24 h urine after administration amounted to 20-30% of the dose. In eight choriocarcinoma patients plasma levels of VP16-213 were measured after oral capsules and drinkable ampoules. The bioavailability compared to the i.v. route was variable, mean values being 57% for capsules and 91% for ampoules. In one further patient, with abnormal d-Xylose absorption results, VP16-213 was not detectable in plasma after the oral ampoule dose. Steady state levels investigated in three patients after 72 h continuous VP16-213 infusion (100 mg/m2/24h) were around 2-5 micrograms/ml. Levels of VP16-213 were undetectable in CSF after i.v. or oral administration.

Hexamethylmelamine distribution in patients with ovarian and other pelvic cancers

The distribution of hexamethylmelamine (HMM) was investigated in surgical biopsies from 12 patients with pelvic cancer who were given an oral dose of 200 mg at 2-24 hours before the operation. The highest concentrations of HMM were found in tissues, such as omentum and subcutaneous tissue, that have a predominant lipidic component. HMM concentrations in the primary tumor were lower than in other tissues and were similar to those in plasma. HMM concentrations in metastases appeared to be higher than in the primary tumor, and in metastases with a diameter less than 3 mm, drug levels were two to ten times those in larger ones. Plotting the HMM concentrations versus time, utilizing the data from different patients, the elimination half-lives were found to be 9.05, 8.82, and 8.53 in plasma, tumor, and subcutaneous tissue, respectively.

The critical cues for diurnal death feigning in young chicks: a functional analysis

The critical determinants of extended diurnal death feigning were assessed in a refinement experiment in which visual and tactile cues during rearing and/or testing were systematically eliminated. Ninety-five domestic chicks were reared in either a social environment or physical (tactile) isolation, and half in each rearing condition were reared and/or tested under conditions of visual restriction. As expected, social rearing was prerequisite to the manifestation of extended death feigning; however, the incidence and duration of death-feigning was attenuated by functional visual isolation of socially reared chicks during either rearing or testing. It was concluded that visual novelty of the environment is the minimal condition for sustained death feigning by young chicks in the daylight hours.