Synthesis of alpha-fetoprotein (AFP) and cell proliferation in regenerating livers of NMRI mice after partial hepatectomy. An immunohistochemical and autoradiographic study with 3H-thymidine

To get more information concerning the relation between cell proliferation and the synthesis of alpha-fetoprotein (AFP), liver regeneration and AFP production was followed simultaneously in short intervals in NMRI mice after two-thirds hepatectomy using autoradiographic and immunohistochemical methods. The results indicate that AFP synthesis is not linked closely to cell proliferation in the sense that each proliferating hepatocyte synthesizes AFP during a definite phase of the cell cycle. However, AFP production, as measured by the index of anti-AFP positive hepatocytes, occurs in a very small population of parenchymal cells when the bulk of the hepatocytes has just passed the S-phase and is considered to be in the G2-, M or early G1-phase of the cell cycle when the cells are still in an undifferentiate state.

Comparative study on human pharmacokinetics of activated ifosfamide and cyclophosphamide by a modified fluorometric test

The activated metabolites of ifosfamide and cyclophosphamide (4-hydroxy-ifosfamide and 4-hydroxy-cyclophosphamide) were analysed fluorometrically by condensation of liberated acrolein with m-aminophenol yielding 7-hydroxyguinoline. Interfering fluorescence of blood and urine was eliminated by extraction with dichlormethane and determination of blanks in which the liberated acrolein reacted with hydrazine to non-fluorescent pyrazoline. The modified test proved effective in identifying low levels of activated metabolites in man. After i.v. injection of 20 mg/kg cyclophosphamide or ifosfamide peak levels of activated cyclophosphamide (4.7 nmol/ml) and the area under the curve (c.t = 16.7 nmol.ml/h) showed mean values three times higher than those found for activated ifosfamide. One per cent of the applied dosis of cyclophosphamide vs. 0.3% of ifosfamide was excreted as activated metabolites. Due to the high stability of activated cyclophosphamide and ifosfamide in urine a low liberation rate of acrolein was found, the concentration of which in urine was below 0.5 nmol/ml. Acrolein, which was directly liberated from activated cyclophosphamide or ifosfamide, does not seem to play an important role in the urotoxicity of these cytostatics.

[Leukocyte-adherence-inhibition reactivity in patients with colorectal and pancreatic cancer (author's transl)]

The immunoreactivity of patients with colorectal or pancreatic cancer was investigated by a modified leukocyte adherence inhibition test (LAI). The microcapillary-LAI-test was easy to practise and measurements had a low intra-assay coefficient of variation. The number of false positive results was low, only 1 of 39 patients with benign disease and not one of 13 healthy volunteers reacted in the presence of colorectal carcinoma extracts. In 43 patients with colorectal cancer 17 of 25 (68%) with Dukes' B & C and 15 of 18 (83%) with Dukes' D cancer were LAI positive. Of the 19 patients with colon polyps 6 positive results were observed, exclusively in case of large villous adenomas, polyposis coli and one polyp with a focal carcinoma. 10 of 11 patients with pancreatic cancer reacted in the test. Leukocytes from patients with limited cancer of other source, when tested with colorectal or pancreatic carcinoma extracts, showed a negative LAI response. However, in case of metastatic diseases some crossreactions were observed, which resulted in false positive tests. Following our results, the LAI test could be of value in the diagnosis of gastrointestinal carcinoma.

[Anatomical and functional changes of the human small intestine induced by 5-fluorouracil (author's transl)]

In 10 female patients with carcinoma the effect of a single dose of 5-fluorouracil on morphologic alterations of the small bowel mucosa, intestinal disaccharidase-activities and lactose-tolerance-test was studied pre- and 96 hours posttherapy. After having given a standard dose of 1,25-1,50 gr 5-fluorouracil intravenously ( = 22 mg per kilo body weight) histologic changes of the small bowel mucosa (slight edema and shortening of the villi) were noted only in 4 cases. In the other cases the small intestine showed no morphological alterations of the mucosa. In all patients the lactose-tolerance-test after therapy with 5-fluorouracil was not affected. Following the administration of 5-fluorouracil no reduction of intestinal disaccharidase activities (maltase, saccharase, lactase) was observed. As a consequence of our results we suppose, that a patient given a single dose of 5-fluorouracil intravenously needs no specific diet without milk or milk-products.

The complex formation between Escherichia coli aminoacyl-tRNA, elongation factor Tu and GTP. The effect of the side-chain of the amino acid linked to tRNA

The interaction between Escherichia coli aminoacyl-tRNAs and elongation factor Tu (EF-Tu) x GTP was examined. Ternary complex formation with Phe-tRNAPhe and Lys-tRNALys was compared to that with the respective misaminoacylated Tyr-tRNAPhe and Phe-tRNALys. There was no pronounced difference in the efficiency of aminoacyl-tRNA x EF-Tu x GTP complex formation between Phe-tRNAPhe and Tyr-tRNAPhe. However, Phe-tRNALys was bound preferentially to EF-Tu x GTP as compared to Lys-tRNALys. This was shown by the ability of EF-Tu x GTP to prevent the hydrolysis of the aminoacyl ester linkage of the aminoacyl-tRNA species. Furthermore, gel filtration of ternary complexes revealed that the complex formed with the misaminoacylated tRNALys was also more stable than the one formed with the correctly aminoacylated tRNALys. Both misaminoacylated aminoacyl-tRNA species could participate in the ribosomal peptide elongation reaction. Poly(U)-directed synthesis of poly(Tyr) using Tyr-tRNAPhe occurred to a comparable extent as the synthesis of poly(Phe) with Phe-tRNAPhe. In the translation of poly(A) using native Lys-tRNALys, poly(Lys) reached a lower level than poly(Phe) when Phe-tRNALys was used. It was concluded that the side-chain of the amino acid linked to a tRNA affects the efficiency of the aminoacyl-tRNA x EF-Tu x GTP ternary complex formation.

[Blood level and urinary excretion of activated cyclophosphamide and its deactivation products in man (author's transl)]

Blood levels and urinary excretion of cyclophosphamide and its metabolites were determined in cancer patients receiving cyclophosphamide. Activated cyclophosphamide (4-hydroxycyclophosphamide aldophosphamide) was assayed by TLC after derivatisation to stable 4-(S-benzyl)-sulfido-cyclophosphamide. Twenty minutes after injection of 10(20) mg/kg cyclophosphamide mean peak levels of activated cyclophosphamide were found to be 1.4(2.6) nmol/ml. The rate constant for biotransformation (=activation) of cyclophosphamide in man (km = 0.132 h-1) was only 1/50 of the value found in the mouse whereas the elimination rate constant of activated cyclophosphamide (ke[M] approximately 6.78 h-1) was much higher equalling that of laboratory animals. 4-ketocyclophosphamide, carboxyphosphamide, and phosphoramidemustard reached their peak levels between 4 and 6 h after cyclophosphamide injection. Increasing quantities of cyclophosphamide metabolites were bound to plasma proteins reaching a constant level after 24 h lasted for several days. Fifty per cent of those metabolites were reversibly bound to plasma proteins. Within 24 h, the cumulative excretion of cyclophosphamide and its metabolites amounted to 50% of the dose applied. The main metabolites excreted were phosphoramide-mustard and carboxyphosphamide whereas only 2% consisted of activated cyclophosphamide. The significance of the different pharmacokinetics of cyclophosphamide in laboratory animals and man for the therapeutic index is discussed.

Mass spectrometric characterization of activated N-(2-chloroethyl)amino oxazaphosphorine derivative

The hydroperoxy and several alkylthio derivatives of the antitumor agents cyclophosphamide (2-bis(2-chloroethyl)amino tetrahydro-2H-1,3,2-oxazaphosphorine 2-oxide), ifosfamide (3-(2-chloroethyl)-2-(2-chloroethylamino)tetrahydro-2H-1,3,1-oxazaphosphorine 2-oxide) and trofosfamide (3-(2-chloroethyl)-2-(bis(2-chloroethyl)amino)tetrahydro-2H-1,3,2-oxazaphosphorine 2-oxide) were characterized by electron impact and field desorption mass spectrometry. The compounds, which are stabilized derivatives of the activated hydroxylated intermediates of cyclophosphamide (ifosfamide, trofosfamide), could be identified as 4-hydroperoxy and 4-alkylthio oxazaphosphorines. The existence of diastereomers of these products was demonstrated by thin-layer chromatography and f.d. mass spectra. Derivatization with benzylmercaptan was found to be an appropriate method for the quantitative isolation and mass spectral identification of the activated metabolic intermediates of cyclophosphamide from biological material. Using this reaction, 4-hydroxycyclophosphamide and its acyclic tautomer, aldophosphamide, which are too unstable for direct identification, were detected in urine and serum of patients treated with 3H-cyclophosphamide.

Characterization and quantitative estimation of activated cyclophosphamide in blood and urine

An assay for the characterization and quantitative determination of activated cyclophosphamide has been described. The method is based on high reactivity of the kryptaldehyde group in 4-hydroxycyclophosphamide with mercapto compounds to yield 4-(S-R)mercaptocyclophosphamide derivatives. The activated cyclophosphamide can be converted quantitatively to 4-(S-benzyl)mercaptocyclophosphamide with benzyl mercaptan, and the mercapto derivative can be separated by thin-layer chromatography on silica gel with ethyl acetate:methyl ethyl ketone as solvent. Using this assay, significant levels of activated cyclophosphamide in the blood of mice and rats, as well as of humans, were found to be present after cyclophosphamide application. The characterization of 4-(S-benzyl)mercaptocyclophosphamide formed was confirmed by comparing the thin-layer chromatographic and mass spectrometric data on this derivative obtained from an authentic sample of 4-hydroxycyclophosphamide.

Regions of tRNA important for binding to the ribosomal A and P sites

Studies on the enzymatic inhibition of phenylalanyl-tRNAPhe and formylmethionyl-tRNAFMet binding to the ribosomes by defined tRNA fragments indicate that beside the anticodon the following regions of tRNA are important for ribosomal A-site interaction: the TppsipCp sequence, the CpCpA end, and hU loop. In contrast, binding to the ribosomal P site is not inhibited by the fragments of uncharged yeast tRNAPhe containing the hU or the TpsiC loop of the molecule. Comparative studies on the inhibitory effect of the oligonucleotides TppsipCpGp and UpUpCpGp indicate that the presence of the minor bases in TpsiC loop is not an essential prerequisite for the binding of tRNA to the ribosomal A site. Furthermore, evidence is presented that shows that the binding of the TppsipCpGp oligonucleotide to the ribosomes influences the ribosomal P site and increases there the efficiency of the codon-anticodon interaction. It is suggested that the TppsipCpGp binds to the ribosomal A site and competes there with the TpsiC loop of the aminoacyl-tRNA for the same binding site. A model for the interaction between tRNA and the ribosomal A site is proposed that involves partial unfolding of hU and TpsiC loops of the tRNA and, therefore, suggests the dynamic involvement of tRNA in protein synthesis.

Studies on 4-hydroperoxycyclophosphamide (NSC-181815): a simple preparation method and its application for the synthesis of a new class of "activated" sulfur-containing cyclophosphamide (NSC-26271) derivatives

4-Hydroperoxycyclophosphamide was obtained in approximately 20% yield by ozonization of cyclophosphamide in acetone/water at 0 degrees C. It was reduced to 4-hydroxycyclophosphamide, which was treated with several mercaptans to yield compounds of the type 4-(S-R)-mercapto-cyclophosphamide. In the solid state these compounds are stable at room temperature; in aqueous solution they are hydrolyzed to 4-hydroxycyclophosphamide or its tautomer, aldophosphamide. One of the 4-(S-R)-mercapto-cyclophosphamide compounds was tested biologically in vitro against Yoshida ascites tumor cells and showed the same cytotoxic activity as 4-hydroxycyclophosphamide.

Identification and pharmacokinetics of cyclophosphamide (NSC-26271) metabolites in vivo

The existence of the cyclophosphamide (CP) metabolites, 4-hydroxycyclophosphamide and aldophosphamide, in vivo after application of CP to mice and rats has been demonstrated. The metabolite pattern in the serum and urine of rats at different times after CP application was determined. For this purpose, thin-layer chromatograpic procedure was developed which allows separation of the metabolites without decomposition. Because considerable amounts of radioactivity are bound to serum proteins after 3H-CP application, protein binding studies with CP and CP metabolites were carried out. It was found that 4-hydroxycyclophosphamide is bound to thiol groups of bovine serum albumin yielding a rather stable product which could be isolated by column chromatography on Sephadex.

[Aneurysm of the arteria lusoria. Report on 4 cases]

Four cases of arteriosclerotic aneurysm of the arteria lusoria are described. In one patient a tumor of the superior mediastinum was suspected, the chief signs of which are dyspnea and irritative cough. In a further patient, enlargement of the left superior mediastinum was noted in routine fluoroscopy. Clinical investigation revealed an aneurysm of the arteria lusoria. In the third patient, dysphagia, slight cough and torticollis were interpreted as symptoms of a neoplasm of the esophagus or larynx. The fourth patient, in whom aneurysm of the arteria lusoria was discovered by chance at autopsy, displayed no clinical or radiological signs. Abberrant right subclavian artery (arteria lusoria) is a relatively frequent finding in autopsies. Aneurysm of the arteria lusori is apparently also a typical complication.

ATPase complex and oxidative phosphorylation in chloramphenicol-induced megamitochondria from mouse liver

1. Functional properties of the ATPase complex are investigated in megamitochondria isolated from livers of weanling mice fed a diet containing 2% chloramphenicol, as an inhibitor of mitochondrial protein synthesis. 2. Whereas the specific activity of ATPase remains unchanged in chloramphenicol-induced megamitochondria, about 40% of the enyzme activity is resistant to inhibition by oligomycin, triethyltin or venturicidin. It is concluded that the ATPase complex lacks one or more components whose synthesis or accumulation is dependent on mitochondrial translation. The inhibitor-resistant ATPase portion appears tightly bound to the mitochondrial membrane. 3. Respiratory chain phosphorylation is tightly coupled in isolated megamitochondria. ATP synthesis and ATP-Pi exchange are diminished by 40%, as compared to control mitochondria, but both processes are sensitive to oligomycin, triethyltin or venturicidin. 4. The decrease in ATP synthesis and ATP-Pi exchange in megamitochondria correlates quite well with the emergence of inhibitor-resistant ATPase. 5. The following electron transport activities in the megmitochondria are reduced: NADH-cytochrome c reductase, by 60%, cytochrome oxidase, by 80%; the amount of antimycin required to gain complete inhibition of the bc1-segment is diminished by more than 50%. On the other hand succinate dehydrogenase activity is increased by 50%. 6. Chloramphenicol-induced megamitochondria appear to be a useful system for studying the role of mitochondrial translation in the assembly of mammalian mitochondria.

[A case of amniotic fluid embolism (author's transl)]

A case of lethal amniotic fluid embolism is reported. The microscopic findings are documented and the patho-physiologic course of events is reconstructed. The unsuccessful treatment is compared with recommendations in the literature and critically evaluated.

The roles of IgG, IgM rheumatoid factor, and their complexes in the induction of polymorphonuclear leukocyte chemotactic factor from complement

The induction of chemotactic factor by rheumatoid factor (RF) and by rheumatoid complexes and their constituents was investigated. The presence of chemotactic factor was measured by the number of polymorphonuclear leukocytes (obtained from normal individuals) attracted through a 3 mum Millipore filter and is expressed as a "chemotactic index." The chemotactic index was used to measure the effect of immunoglobulins and their complexes in stimulating production of complement-derived chemotactic factors from the sera of normal individuals. Two sources of IgG (F-II and DEAE-purified IgG) were used. These were prepared for use in the native and heat-aggregated states. The same chemotactic index was obtained with both these preparations of IgG. The chemotactic index increases when (a) increasing concentrations of gamma globulin were added to a constant concentration of complement and (b) when the amount of complement alone was increased. The addition of a purified IgM RF to the mixture of IgG and complement caused a decrease in the chemotactic index. Incubation of IgG and complement before addition of IgM RF produced no change in the chemotactic index. The addition of a nonrheumatoid factor IgM to IgM and complement had no effect on the chemotactic index. IgM RF and IgG alone were not chemotactic. These studies confirm the concept of "complement deviation" by IgM RF which occurs with, and as a result of, the immune complex formation between IgG and IgM RF. The successful activation of complement chemotactic factors by IgG may explain the synovitis with high polymorphonuclear leukocyte counts found in RF-negative arthritis.