Immunotherapy of xenografted human bladder cancer in nude mice using monoclonal antibody

A murine monoclonal antibody with IgG3 isotype and k-light chains has been produced against a human bladder cancer cell line, TSGH-8301. Radioimmunoassay and immunofluorescent staining revealed that the highly reactive tumor-associated antigen was located on the cell surface of TSGH-8301 transitional cell carcinoma cells. The monoclonal antibody possessed direct and complement-mediated cytotoxicity to TSGH-8301 cancer cells as shown by in vitro microcytotoxicity test. Further trials on the immunotherapy of xenografted tumors in nude mice using the monoclonal antibody demonstrated that the therapeutic efficacy was dose-dependent and closely related to tumor burden.

Transitional cell carcinoma of the kidney with extension into the inferior vena cava

A case of transitional cell carcinoma of the kidney, invading the inferior vena cava, is presented. Preoperative diagnosis is almost impossible and frozen section is necessary to decide the type of surgery. Radical surgery with removal of thrombi was performed in our patient but was obviously not helpful. The value of aggressive surgery is not clear. This may be the 6th case in the literature.

Natural killer cell activity in patients with urologic cancer

Cell-mediated cytotoxicity in patients with urologic cancer was studied using the K562 cell line as target cell by a 4-hour chromium-51 release assay. Lysis of target cells by mononuclear cells of a healthy subject, over an 8-hour incubation period, demonstrated a linear function of incubation time and effector:target ratio. Natural killer (NK) cell activity was found decreased (mean 30.6%) in peripheral blood lymphocytes from 42 untreated patients with urologic cancer when compared to 20 healthy subjects (63.6%) and to 10 patients with varicocele, stone disease and benign prostatic hypertrophy (58.1%; p less than 0.05). There was no correlation between NK cell activity and the grade or stage status in bladder cancer patients. No age-dependent changes in NK cell activity could be found between young and aged groups of healthy subjects. Healthy male subjects have higher levels of NK cell activity (77.7%) than healthy female subjects (49.5%). Postoperative NK activity rose in 5 out of 6 cancer patients. It indicates that tumors may have an inhibitory effect on the surveillance activity of NK cells.

Benign testicular tumors

Testicular tumor is considered rare in Oriental people and benign testicular tumor has never been reported from this area. From 1969 to 1985 70 cases of intratesticular tumors were treated at Tri-Service General Hospital. 12 of them were benign in nature including 8 epidermoid cysts, 1 cavernous hemangioma, 1 foreign body granuloma with pseudocyst, 1 Sertoli cell tumor and 1 intratesticular simple cyst. A testis-sparing procedure was performed for 5 epidermoid cysts, the Sertoli cell tumor and the simple intratesticular cyst. The tumors were excised completely and the testes were preserved after careful and thorough frozen section pathological studies. One of the epidermoid cysts and the case of simple testicular cyst were diagnosed correctly before surgery by using scrotal ultrasound.

Processing of Bacillus licheniformis penicillinases lacking a lipoprotein modification site in Escherichia coli

We have previously shown that the penP Ser-27 prepenicillinase is processed into two forms, Ser-35-penicillinase and Asn-29 penicillinase. Two new penicillinase mutants, penP Ser-27 Pro-28 and penP Ser-27,23' (Pro-Asp)24', were derived from the penP Ser-27 mutant by oligonucleotide-directed site-specific mutagenesis. The penP Ser-27 Pro-28 mutant prepenicillinase was also processed into two forms, Ser-35-penicillinase and Gly-26-penicillinase. On the contrary, the penP Ser-27,23' (Pro-Asp)24' mutant prepenicillinase is unprocessed.

Covalent adduct formation and chloroform production after free radical attack on fatty acids by carbon tetrachloride reactive intermediates

The interactions of fatty acids and the trichloromethyl free radical generated anaerobically by the benzoyl peroxide model system were studied. Chloroform was produced due to the interaction of the trichloromethyl free radical with the unsaturated fatty acid ester methyl oleate, indicating the hydrogen in chloroform may result from abstraction from fatty acids. In addition, chloroform was detected in incubations containing the saturated fatty acid ester methyl stearate, indicating hydrogen abstraction is not limited to allylic hydrogens. Mass spectral analysis identified one adduct resulting from additional reactions to methyl oleate, and an adduct resulting initially from hydrogen abstraction on methyl stearate. These findings describe previously unreported reactions of the trichloromethyl free radical with saturated fatty acid, and inhibition of chloroform production by 3 free radical inhibitors.

Modification and processing of internalized signal sequences of prolipoprotein in Escherichia coli and in Bacillus subtilis

We have cloned the Escherichia coli lipoprotein structural gene (lpp) into a shuttle vector and studied its expression in both E. coli and in Bacillus subtilis. Using in vitro gene fusion techniques, the lpp gene was placed under the control of the promoter for the erythromycin-resistance (ery) gene. This fusion gene directed the synthesis of Braun's prolipoprotein which can be subsequently processed into the mature lipoprotein. In addition to the prolipoprotein, two ery-lpp hybrid proteins containing a 45- and a 22-amino acid extension preceding the NH2 terminus of prolipoprotein, respectively, are also synthesized in E. coli. The synthesis of these three proteins appears to involve the utilization of three distinct translation initiation sites. In B. subtilis, only two proteins are synthesized, the hybrid protein with a 45-amino acid extension and the prolipoprotein. In both E. coli and B. subtilis, the precursor forms of the hybrid proteins are lipid-modified, and they are processed to mature lipoprotein in vivo. These results indicate that internalized signal sequence containing the prolipoprotein modification and processing site (Leu-Ala-Glys-Cys) can function normally and permit the modification of hybrid proteins to lipid-modified precursors which can be subsequently processed by the globomycin-sensitive prolipoprotein signal peptidase.

Identification of prolipoprotein signal peptidase and genomic organization of the lsp gene in Escherichia coli

The product of the lsp gene of Escherichia coli, i.e. the prolipoprotein signal peptidase, was identified by both in vivo pulse labeling experiments using a high expression lambda PL promoter vector and by an in vitro transcription/translation coupled system. The molecular weight of prolipoprotein signal peptidase was estimated to be approximately 18,000 by its mobility on polyacrylamide gel electrophoresis and was found to be the same as that of SPase II purified from the wild-type cells. Analysis of SPase II activities in strains containing various subclones, deletion derivatives generated from plasmid pMT521, and analysis of protein products in a strain harboring an ileS-lsp-fused gene indicated that ileS and lsp genes are transcribed on the same mRNA. This was further supported by the observation that Tn5 insertions in the ileS gene resulted in a reduced expression of the lsp gene. In addition to an upstream promoter shared by the ileS and lsp genes, these analyses also revealed the presence of an internal promoter for the lsp gene within the coding region of the ileS gene.

Studies of early laryngeal reinnervation

In 1973, Hengerer and Tucker reported a method for laryngeal reinnervation. The purpose of this study is to objectively verify the reinnervation mechanism in 20 dogs with nerve-muscle pedicle grafts. Three months after the experimental operation direct stimulation of the nerve to the neuromuscular pedicle produced an evoked action potential of the posterior cricoarytenoid muscle. This was recorded. Histologic examination of the posterior cricoarytenoid muscle and the nerve-muscle pedicle were performed. The electromyogram revealed in ten of fifteen dogs an excitable action potential. This can be considered as objective evidence for reinnervation from the neuromuscular pedicle.

Recombination following transformation of Escherichia coli by heteroduplex plasmid DNA molecules

Circular heteroduplex DNA molecules introduced into Escherichia coli-competent cells are converted to new recombinant plasmids as a result of enzymatic actions in vivo. A pair of plasmids with partial sequence homology were each linearized at a different position with restriction enzymes, and the termini were made flush with the single-strand-specific S1 nuclease. Duplex molecules were then formed by melting and annealing these plasmid DNAs together. In contrast to linear homoduplex molecules, heteroduplexes circularize and therefore transform E. coli efficiently. Unique DNA sequences on each of the parental strands in the transforming heteroduplexes can be selectively incorporated or deleted as a result of in vivo enzymatic activities in transformed cells. This method permits the generation of new recombinant sequences in vivo without relying solely on the presence of convenient restriction sites for manipulation of DNA fragments in vitro.

Modification and processing of Bacillus licheniformis prepenicillinase in Escherichia coli. Fate of mutant penicillinase lacking lipoprotein modification site

We have previously shown that Bacillus licheniformis prepenicillinase is modified and processed to form membrane-bound penicillinase in Escherichia coli which contains N-acylglyceride-cysteine27 at the NH2 terminus. In the present study, we have constructed, by in vitro site-directed mutagenesis, two mutant penicillinase genes in which the modification site (the 27th cysteine residue in prepenicillinase) is either converted into serine (penPSer27) or is deleted along with the preceding four residues (Ala23 to Cys27, delta penP2327). The modification, processing, and subcellular localization of these two mutant penicillinases in E. coli cells were studied. Our results indicate that the delta penP2327 deletion mutant prepenicillinase is largely metabolically inert and the unmodified and uncleaved form is associated with the membrane fraction; a small fraction (about 7-9%) appears to contain glyceride-modified prepenicillinase (presumably at the Cys-21 position) which is not cleaved. In contrast, the Cys-27 in equilibrium Ser-27 point mutant prepenicillinase is processed into two forms which contain Asn-29 and Ser-35 at their NH2 termini, respectively, and the bulk of the processed penicillinase appears to be located in the peri-plasm. These results are discussed in terms of the substrate specificities of signal peptidases in E. coli.

Nucleotide sequence of the Escherichia coli prolipoprotein signal peptidase (lsp) gene

The nucleotide sequence of the prolipoprotein signal peptidase (lsp) gene has been determined. The lsp gene was found to be adjacent to the isoleucyl-tRNA synthetase ( ileS ) gene, such that the termination codon of the ileS gene overlaps with the initiation codon of lsp. These two genes are transcribed in the same direction and the major promotor for the lsp gene appears to be upstream of ileS . Identification of the lsp gene was established by amplification of prolipoprotein signal peptidase activity in strains carrying a subcloned 1.1-kilobase Stu I-Acc I fragment and was further confirmed by introducing mutational alterations in the COOH terminus of the protein that caused a decrease in prolipoprotein signal peptidase activity. The deduced amino acid sequence indicates that prolipoprotein signal peptidase contains 164 residues. Unlike most exported proteins, there is no apparent signal peptide sequence for the lsp protein. Computer-assisted secondary structure analysis of the deduced amino acid sequence identified four hydrophobic regions that share features common to transmembrane segments in integral membrane proteins.

Povidone-iodine bladder injury in rats and protection with heparin

Povidone-iodine (Betadine) has been proposed for clinical use in controlling bacterial infections by intravesical instillation in concentrations ranging from 0.1 to 1 per cent. The effects, however, of povidone-iodine on the urothelium of the bladder have not been well studied. We performed experiments to see if injury to the urothelium occurred from intravesical instillation in female rats. Injury was indeed found with concentrations of 0.3 per cent and 1 per cent povidone-iodine, as judged by the observations of increased bladder weight due to edema, histological examination, in vivo bladder staining, crystal adhesion and bacterial adhesion upon the bladder mucosa after povidone-iodine injury. Further study showed that the urothelium recovered in 6 to 7 days after povidone-iodine injury, while a 3rd experiment demonstrated at least partial protection from bacterial and crystal adhesion to povidone-iodine injured urothelium by immediate treatment with heparin instillation in the bladder.

Transcriptional analyses of the Bacillus licheniformis penP gene

We report the promoter structure of the Bacillus licheniformis 749/C penicillinase (penP) gene. The transcript encoding the penicillinase gene was identified by in vitro run-off transcription using both E. coli RNA polymerase and B. subtilis RNA polymerase. Utilization of this promoter in linearized DNA by the B. subtilis RNA polymerase showed extreme sensitivity to ionic strength. The 5' sequence of the penP mRNA was determined using enzymatic sequencing (1). Holoenzymes from E. coli and B. subtilis (E sigma 55) initiate penP RNA synthesis at the same site. Alignment of this RNA sequence with the reported DNA sequence of ther penP gene (2,3) revealed the "-35 region" and "Pribnow box" sequences that are recognized as 5'TTGCAT and 5'AATACT, respectively. Potential secondary structure within the promoter exists which may play a role in the expression of the penicillinase gene. The location of the penP promoter was further confirmed by molecular cloning of a DNA fragment containing the expected promoter sequence into a promoter-fishing vector useful for monitoring promoter activities in both E. coli and B. subtilis.

In vitro degradation of L-phenylalanine mustard (L-PAM)

L-Phenylalanine mustard (L-PAM), a bis-choroethylamine, is an important drug in the treatment of multiple myeloma and ovarian cancer. It undergoes rapid hydrolysis in vitro and in vivo, forming the mono-and dihydroxy degradation products. L-PAM's first-order disappearance rate in a phosphate-buffered solution did not differ statistically according to the presence or absence of activated rat liver microsomal enzymes. Furthermore, L-PAM's disappearance rate in a rat whole liver perfusion system was not greater than its hydrolysis rate in water. In vitro plasma recovery studies showed that up to 85% of the 14C L-PAM drug equivalents could be recovered as the parent compound and the mono- and dihydroxy degradation products. Thus, L-PAM in in vitro degradation was similar qualitatively and quantitatively to its reported in vivo degradation in animals and man. It is concluded that L-PAM does not undergo important, active in vivo metabolism.

Concentration profile for the dissolution of drug tablets undergoing simultaneous degradation

An empirical approach to the concentration-time history of a dissolving drug has resulted in a cube-root equation in which the characteristic constant of the equation embodies the important physical variables of the system. This expression has been used to study the dissolution of a drug that degrades simultaneously in the test solution. An alternative representation of the dissolution process is first-order kinetics. These two approaches are compared by fitting the experimental data of the dissolution of digoxin and melphalan tablets in various media, and a new method for the proper analysis of data for the dissolution of tablets that simultaneously degrade in the test solution is presented.

A rapid method for taurine quantitation using high performance liquid chromatography

Presented is a fluorometric technique for the quantitative analysis of taurine in biological samples. The sample is homogenized, treated with picric acid, and passed through a mixed-bed, ion-exchange column. The eluant is lyophilized, reconstituted, and an aliquot derivatized with o-phthalaldehyde (OPA) prior to high performance liquid chromatography (HPLC). The ion-exchange column removes all amino acids, cysteic acid, phosphoethanolamine, and hypotaurine while allowing quantitative recovery of taurine. Using the procedure as outlined, quantitation has been performed from 0.080-1.6 nmoles per analysis. The lower limit of quantitation, using the equipment specified, was shown to be 5 pmoles per analysis. The method allows rapid sample processing while maintaining a high degree of sensitivity and accuracy.

The disposition of intraperitoneal bleomycin, melphalan, and vinblastine in cancer patients

We have studied the disposition of bleomycin, melphalan, or vinblastine after intraperitoneal (IP) instillation in 14 cancer patients. Although IP bleomycin had a somewhat longer terminal-phase plasma half-life than after intravenous (IV) administration (5.5 vs 4.0 h, respectively), its systemic absorption averaged only 44%-52% of the administered dose. IP melphalan's mean terminal-phase half-life of 1.3 h was similar to that seen after IV drug administration. Melphalan's systemic absorption form the IP space averaged only 39% of the administered dose. In contrast, vinblastine plasma levels remained elevated for longer than 24 h after IP instillation. Its use was associated with life-threatening adynamic ileus in two patients. Bleomycin's and melphalan's reduced systemic availability after IP dosing suggests that their dose could be increased safely by a factor of two over their standard IV doses.

Mass spectrometry of chlorambucil, its degradation products, and its metabolite in biological samples

A sensitive and specific method for the determination of chlorambucil and its metabolite in biological fluids is reported. The method is based on selected-ion monitoring detection following simple extraction of the parent compound, its metabolite, and an internal standard (chlorambucil-d8) from plasma and urine samples. The precision (reproducibility) of the method was 94.3 +/- 1.3% with 200 ng of chlorambucil added to 1 ml of plasma. Chlorambucil degradation or alkylation of plasma proteins was minimal with plasma incubated at 24 degrees for 4 hr. However, chlorambucil recovery decreased to 56% after plasma incubation at 37 degrees for 4 hr. Three chlorambucil degradation products in ethyl acetate solution were found, and their structures were studied by mass spectrometry.

Comparative pharmacokinetics of chlorambucil and melphalan in man

We have studied the pharmacokinetics of orally administered chlorambucil and melphalan in patients with hematologic malignancies and solid tumors. With a standard oral dose of 0.6 mg/kg, chlorambucil showed much more rapid systemic appearance than did melphalan and had a mean peak plasma concentration and area under the plasma disappearance curve which was 3-4 times greater than that observed in patients receiving melphalan. Melphalan had extremely variable systemic availability which was not observed with chlorambucil, and was not related to problems in tablet formulation. Chlorambucil undergoes extensive active metabolism to phenylacetic acid mustard, whereas melphalan undergoes rapid chemical degradation and has little, if any, active metabolism. On a pharmacokinetic basis, chlorambucil's greater in vitro stability, its more rapid and predictable systemic availability after oral dosing, and its extremely low urinary excretion make it a more predictable alkylating agent for clinical use than melphalan, especially for patients with reduced renal function.

Oral melphalan kinetics

The systemic availability of melphalan after oral administration is not well known. Most patients are put on a fixed oral dosage regimen. We have studied the disposition of melphalan in 14 patients after single oral doses. Five were also studied after receiving the same dose intravenously. Oral melphalan had a mean plasma terminal phase half-life (t1/2) of 90 +/- 17 min. The mean area under the plasma concentration:time curve (CXT) was 53 +/- 33 micrograms . min/ml. Urinary excretion of oral melphalan averaged 10.9 +/- 4.9% during the first 24 hr. The CXT ratio (oral:intravenous) for the 5 patients studied after both oral and intravenous melphalal (0.6 mg/kg) ranged between 0.25 and 0.89 and averaged 0.56. After oral dosing in 14 fasting patients, the time at which melphalan first appeared in the plasma varied between 15 min and 6 hr. In a myeloma patient who took oral melphalan, no melphalan was found in plasma or urine up to 24 hr. Some instances of failure of tumor response to oral melphalan may be due to inadequate bioavailability rather than inherent tumor resistance.

Kinetics of intravenous melphalan

We have studied the disposition and elimination of melphalan after intravenous administration in 9 patients with cancer. High-pressure liquid chromatography and 14C-melphalan were used to assay drug concentration in plasma and urine. Composite plasma t1/2alpha was 7.7 +/- 3.3 and t1/2beta was 108 +/- 20.8 min for 8 of the patients. The mean 24-hr urinary excretion of melphalan was 13.0 +/- 5.4% of the administered dose. In 2 patients, 80% to 100% of the measured 14C counts in plasma and urine samples at each study interval, up to 24 hr after drug administration, could be accounted for by the sum of parent compound, monohydroxy and dihydroxy products, and methanol nonextractable radioactivity (i.e., protein-bound activity). These data and evidence of rapid disappearance from plasma at 37 degrees in vitro suggest that spontaneous degradation, and not enzymatic metabolism, is the major determinant of the t1/2 of melphalan in vivo.

Location by paper chromatography of compensatory ovarian hypertrophy (COH) inhibiting activity in acetic acid extracts from bovine pineals

Acetic acid extracts of bovine pineals and cerebral cortex were separated on Sephadex G-25 columns. Subsequently two low molecular weight fractions, F2 and F3, were ultrafiltered through the membranes UM2 and UM05. The UM05 residues were gel filtered on Sephadex G-15 columns or chromatographed on Dowex W50-X4 columns. Fractions from these columns were tested and those which showed COH-inhibiting activity were separated by preparative paper chromatography in different solvents. The absorption spectra of those fractions were recorded and tested for COH-inhibiting activity were separated by preparative paper chromatography in different solvents. The absorption spectra of those fractions were recorded and tested for COH-inhibition. By these methods, a COH-inhibitor was localized in three different solvents. Some active paper chromatography fractions were studied in high pressure, reverse phase, liquid chromatography. This latter method showed that the active fractions obtained by paper chromatography contain several orthophthlaldehyde (OPT) positive compounds. Key words: acetic acid, bovine pineal extracts, compensatory ovarian hypertrophy (COH), paper chromatography, high pressure, reverse phase, liquid chromatography.

Hydrolysis and protein binding of melphalan

Melphalan (30 microgram/ml) is completely hydrolyzed in water at 37 degrees after 8 hr. At lower temperatures, hydrolysis proceeds at slower rates. The presence of bovine serum albumin retards hydrolysis of melphalan (30 microgram/ml) in water. The melphalan hydrolysis rate is directely releated to the bovine serum albumin concentration. At 37 degrees, 8 g of bovine serum albumin/100 ml of water gives a recovery rate of melphalan similar to that of human plasma. In vitro alkylation of melphalan at 37 degrees with human plasma containing 30 microgram/ml, calculated by equilibrium dialysis, methanol extraction, and high-pressure liquid chromatographic analysis, is 30% after 8 hr.

Reverse phase high pressure liquid chromatography for the separation of peptide hormone diastereoisomers

Diastereoisomers of specifically labeled oxytocin derivatives were resolved using reverse phase high pressure liquid chromatography. The peptides [1-hemi-DL-[alpha-2H]cystine]oxytocin, [6-hemi-DL-[alpha-2H]cystine]oxytocin, [2-DL-[alpha-2H]tyrosine]oxytocin and[8-DL-[2-13C]leucine]oxytocin were readily separated using the conditions described. The diastereoisomers of the oxytocin analog [3-DL-[2-13C]leucine]oxytocin also demonstrated baseline resolution under the same conditions. The procedure offers the investigator a rapid method for screening synthetic oxytocin peptides for undesirable diastereoisomeric by-products.

High-pressure liquid chromatographic analysis of melphalan in plasma

A new sensitive and rapid high-pressure liquid chromatographic determination of melphalan in plasma was developed. Recovery of 1 microgram added to 1 ml of plasma at 23 degrees was 94% but was greatly reduced at higher temperature. The method has been applied to plasma determinations of melphalan in rats and humans and is currently being utilized for human pharmacokinetic studies.

Identification of ejaculate derived propylamine found in collagen sponge contraceptives

Propylamine is identified as one of the compounds present in odoriferous intravaginal contraceptive sponges from sexually active women. This compound also appears in samples of human ejaculate incubated at 37 degrees C for seven days. We have identified propylamine by gas liquid chromatography, mass spectroscopy and as N-propylbenzoylamide. Evidently the compound forms enzymatically from spermine and spermidine. We believe that this is the first time that propylamine has been identified as forming from human tissue.

Genetic analyses of "paranoiac" mutants of Paramecium tetraurelia

Six mutants of Paramecium tetraurelia with curious "Paranoiac" phenotypes have been isolated and examined. Instead of the normal transient avoiding reactions in Na+ solution, these mutants show "violent avoidances"--backing continuously for 10 to over 60 sec. This behavior corresponds to prolonged membrane excitation excitation.--Genetic analyses establish five genic loci at which mutations give the "Paranoiac" phenotype. Close linkage between two of these genes occurs. Allelic variants are found for two of the genes. In one case, the two alleles determine very different behavioral phenotypes ("Paranoiac" and "fast-2"). These results show that the mechanism(s) which shuts off excitation in the wild-type membrane is (are) complex, but in the future may be fruitfully pursued in mutants which are defective.

Selection and analysis of a mutant Paramecium tetraurelia lacking behavioural response to tetraethylammonium

We selected a mutantParamecium tetraureliawhich does not exhibit avoiding reaction in solutions of tetraethylammonium (TEA+), a known membrane K+-channel blocker. Behavioural reaction of the mutant to Na+solutions was also weak. The rapid successions of avoiding reactions in Ba2+solutions were observed in both wild type and the TEA-insensitive mutant. Formal genetic analyses showed that this mutant is due to a recessive mutation. This mutation is on a gene completely unlinked to and hypostatic in different degrees to the genes for the membrane defects of ‘pawn A’, ‘pawn B’, ‘ts-pawn C’, ‘fast-2’ and ‘paranoiac A’.

Duvatrienediols in cuticular wax of Burley tobacco leaves

4, 8, 13-Duvatriene-1, 3-diol diastereoisomers have been identified in the cuticular wax of fresh Burley tobacco leaves. Their structures were determined by gas-liquid chromatography, mass spectrometry, and infrared and ultraviolet spectroscopy. Butylboronic acid derivatives of the alpha, beta-isomers were separated by gas-liquid chromatography and identified by mass spectrometry. The quantitative determination by gas-liquid chromatography revealed that the duvatrienediols are major components in the cuticular wax of Nicotiana tabacum. The duvatrienediol content in young leaves is higher than in old leaves, and in young leaves this compound may account for half of the cuticular wax.

The urinary excretion of nucleosides of ribonucleic acid by patients with advanced cancer

By means of a sensitive and specific method utilizing gas-liquid chromatography, the excretion levels for three nucleosides, degradation minor base products of ribonucleic acid, primarily transfer ribonucleic acid, were determined in 24-hour urine specimens from over 200 patients with solid tumor malignancies. These nucleosides were N2,N2-dimethylguanosine, l-methylinosine, and pseudouridine. When compared to normal control values, elevated levels of these compounds were found for patients in each of several tumor types studied. Increases in pseudouridine excretion suggest increased tumor transfer ribonucleic acid turnover; in addition, for the methylated nucleosides, higher than normal values may reflect enhanced transfer ribonucleic acid methylase activity of the neoplastic cells.

Membrane excitability: made temperature-dependent by mutations

Three mutants of Paramecium aurelia with genetic lesions at two unlinked loci lost their ability to generate action potentials when grown at high temperatures. Action potentials found at room temperature were slightly aberrant. Kinetics of phenotypic changes after temperature shifts showed that excitation is not immediately sensitive to temperature change in these mutants. The initiation of an action potential must rely on many different gene products (presumably membrane proteins) which are open to modification by conditional as well as unconditional mutations.

An extensive behavioural and genetic analysis of the pawn mutants in Paramecium aurelia

Pawns are behavioural mutants which show impairment in membrane excitability and are, therefore, devoid of normal avoiding reactions. We obtained 103 lines of Pawns through mutagenesis and screening. Among those that yielded to breeding studies, 59 lines belonged to thepwAcomplementation group and 38 lines belonged to thepwBgroup. No other genic loci were found in this extensive analysis. Mutants of thepwAlocus showed various degrees of phenotypic leakiness. Based on the pheno- and genotypic differences, we estimated that at least 45 independent mutational events were represented in these 103 Pawn lines.

GENETIC ANALYSES OF HEAT-SENSITVE PAWN MUTANTS OF PARAMECIUM AURELIA

Heat-sensitive Pawn (ts Pawns) of Paramecium aurelia behaved normally when grown at 23° but failed to avoid strong stimuli at 35°. Four of the five ts Pawn lines tested were found to be allelic at a locus known also to carry temperature-independent Pawn mutations. The fifth ts Pawn line complemented all the conditional and unconditional Pawn mutants of the two known loci. This result, together with the patterns of F2 segregation from various crosses, suggested the existence of a third Pawn locus. An additive effect of the unlinked ts Pawn genes was observed. These findings and the significance of ts Pawns as experimental material in behavioral and physiological research are discussed.

Temperature-sensitive pawns: conditional behavioral mutants of Paramecium aurelia

"Pawns" are mutants of Paramecium aurelia in which the process of calcium activation during membrane excitation is genetically impaired, with a corresponding loss of avoiding reactions. Mutants are selected that behave normally when grown at 23 degrees C but as pawns at 35 degrees C. The normal excitation can now be disrupted and restored in the same strain at will.