Metal ion requirement and tryptophan inhibition of normal and variant anthranilate synthase-anthranilate 5-phosphoribosylpyrophosphate phosphoribosyltransferase complexes from Salmonella tyrhimrium.

1. Both Mn2+ and Co2+ can replace Mg2+ as the required divalent cation for all activities of the enzyme complex between anthranilate synthase (chorismate pyruvate-lyase (amino-accepting), EC 4.1.3.27) and anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferase (N(5'-phosphoribosyl)-anthranilate:pyrophosphate phosphoribosytransferase, EC 2.4.2.18) from Salmonella typhimurium. They have much lower apparent Km values than Mg2+, both for glutamine-dependent anthranilate synthase (Mn2+ = 1.1 muM, Co2+ - 2.6 muM, Mg2+ = 83 muM) and for phosphoribosyltransferase (Mn2+ = 16 muM, Co2+ = 14.6 muM, Mg2+ = 133 muM). The ratio of total Mg2+ to total Mn2+ found in a cell extract of S. typhimurium trpE2 , the source of normal enzyme complex, was found to be 350, suggesting that Mg2+ is probably utilized by the enzyme complex in vivo under our growth conditions. 2. An enzyme complex has been isolated from a mutant strain of S. typhimurium (SO-515) that has a variation in the anthranilate synthase subunit which is thought to be a single amino acid substitution. This variation causes glutamine-dependent anthranilate synthase to be hypersensitive to feedback inhibition by tryptophan (Ki = 0.4 muM compared to Ki = 20 muM for normal enzyme complex). The phosphoribosyltransferase in the variant enzyme complex is also hypersensitive to tryptophan but the kinetics are complex and involve activation by tryptophan in the presence of low amounts of 5-phosphoribosyl 1-pyrophosphate. 3. In the variant enzyme complex the apparent Km for Mg2+ is elevated to 360 muM for glutamine-linked anthranilate synthase but reduced to 75 muM for phosphoribosyltransferase. 4. These results suggest that the variant enzyme complex has altered tertiary and quaternary structures and that regulation of both activities is effected by tryptophan binding to only anthranilate synthase.


Translation of a stable mRNA fraction from sporulating cells of Bacillus thuringiensis in a cell-free system from Escherichia coli. Structural homologies between the native crystal protein and the products synthesized in vitro.

Stable messenger RNAs from sporulating cells of Bacillus thuringiensis were translated in vitro in cell free system from E. coli. The mRNA fraction used was extracted from cells treated at t4 of sporulation time with rifampicin for 10 minutes at 30degreesC. This stable-mRNA enriched fraction directed the synthesis of polypeptides showing a size distribution up to 40,000 daltons. Structural homologies between the in vitro products labeled with [3H]-valine and the native crystal protein labeled with [14C]-valine were shown by ion-exchange chromatography after CNBr treatment and by ion-exchange chromatography after digestion of the CNBr-peptides with pepsin. Specific antibodies obtained against the CNBr-peptides of the native crystal protein gave a positive reaction with the in vitro products. SDS-gel electrophoresis confirmed the structural similarities between the two types of immuno-precipitates. It was concluded that the stable-mRNA fraction used directed the synthesis of at least parts of the crystal polypeptide chain. Furthermore, the higher stability of the sporulation phase mRNAs compared to that of the vegetative phase species deduced from previous in vivo experiments was supported by the results obtained in vitro.


UGA mutations and UGA suppressors in yeast.

Eight UGA alleles have been obtained in S. cerevisiae. Two UGA alleles, ade5,7-143 and gal10-1, were isolated as forward mutations from wildtype. Six UGA alleles, arg4-2' (UGA), his5-2' (UGA), ilv3-1' (UGA), leu2'1' (UGA), lys1-1' (UGA), and asp5-1' (UGA), were derived from UAA alleles by selecting from revertants in the presence of UGA suppressors. With these 8 UGA alleles, two classes of UGA-specific suppressors can be distinguished. Suppressors in one class act upon all 8 allelqs ; while suppressors in the second class act upon all but 3 alleles : ade5,7-143, arg4-2' (UGA), and gal10-1.


Purification and properties of two initiation factors from Bacillus stearothermophilus.

Two initiation factors have been isolated from the thermophilic bacterium, Bacillus stearothermophilus, and purified to near homogeneity. The two factors possess physical characteristics and activities associated with the E. coli initiation factors IF-2 and IF-3, and are interchangeable with these factors. The two systems present, however, several differences : S-IF-2 is significantly more heat stable than E. coli IF-2, loosing less than 50 per cent of its activity after 20 minutes at 70degreesC. S-IF-2 alone is unable to promote initiation complex formation on B. stearothermophilus or E. coli ribosomes, and S-IF-3 is absolutely necessary for initiation of complex formation on B. stearothermophilus ribosomes. No factor corresponding to IF-1 has been found. S-IF-3 appears to be able to replace at least partially IF-1, since S-IF-3 and E. coli IF-2 are sufficient to promote maximum fMet-tRNA binding to E. coli ribosomes, while E. coli IF-3 and IF-2 also require IF-1. The differences between the two systems are perhaps required because of the elevated temperature at which B. stearothermophilus normally grows.


[New studies on inhibition of tRNA N2 guanine methyltransferase by S-adenosyl-homocysteine and S-adenosyl-methionine analogs].

New structural analogs of S-adenosyl homocysteine (SAH) 1-9, 11-14, 19-21) and of S-adenosyl methionine (15-18) have been tested as inhibitors of a N-2 guanine methyltransferase extract from rabbit liver with E. coli B tRNA as substrate. The sulfonium compounds (mixture of +/- diastereoisomers) are more inhibitory than the sulfide derivatives but less inhibitory than SAH itself. The replacement of the aminoacid chain in SAH by various alphatic radicals leads to a correlation between their bulk and the size of the enzymatic site. The monosubstitution of N-6 amino group does not affect significantly the inhibitory effect, which is completely canceled by the disubstitution of N-6.


Non specific induction of arginase in Saccharomyces cerevisiae.

Some aminoacids metabolically and structurally unrelated with arginine catabolic compounds induce arginase. This effect designated as non specific induction procedes by a mechanism distinct from three others acting on the synthesis of arginase : specific induction, nitrogen catabolite repression and catabolic synergism.


Control of enzyme synthesis and stability during sporulation in Saccharomyces cerevisiae.

Studies were undertaken to understand the control of synthesis, stability and modification of UDP galactose epimerase and DNA-dependent RNA polymerase during sporulation of Saccharomyces cerevisiae. When a pre-induced culture of an inducible strain (wild type) is transferred to sporulation medium, the epimerase is inactivated to an undetectable level within 16 hours. Surprisingly, the addition of cycloheximide, a protein synthesis inhibitor, during sporulation stabilizes the epimerase activity. However, in a constitutive strain, the epimerase continues to be synthesized de novo during sporulation. Since the enzyme is synthesized during both vegatative growth and sporulation constitutively, the controls for synthesis of epimerase must be similar under these physiologically different conditions. After chromatography on DEAE Sephadex, there is no change observed in the elution patterns of RNA polymerase forms extracted from acetate growth vegetative cells, sporulating cells or from mature asci ; in all cases RNA polymerase consists of three forms, Ib, II and III. However, single spore suspension obtained from asci by treatment with zymolase contains a new form with chromatographic properties similar to those of form Ia. Our data suggests that form Ia may be a modification product of from Ib.


Purification and properties of threonine deaminase from Saccharomyces cerevisiae.

Threonine deaminase (L-theonine hydro-lyase (deaminating), E.C. 4.2.1.16) has been purified to homogeneity from extracts of Saccharomyces cerevisiae. When purified 1200-fold, the enzyme is homogeneous by the criterion of sodium dodecyl sulfate-polyacrylamide electrophoresis. The reduced and alkylated protein has a molecular weight of approximately 50,000 daltons, one-fourth the value determined previously for the intact enzyme. The purified enzyme exhibits homotropic effects with the substrate; these effects are descresed in the presence of DL-allothreonine, a competitive inhibitor. Half-maximal velocity is achieved at 34 mM L-threonine in the absence of other effectors. L-isoleucine both stimulates at low (0.01-0.05 mM) concentrations and inhibits at high (0.1-1.0 mM) concentrations. Valine activates the enzyme in the absence of isoleucine ; in the presence of isoleucine it reverses inhibition.


[Escherichia coli K12 mutant with increased RNA content and messenger RNA stability].

A strain of Escherichia coli has been isolated from a E. coli HfrH after a treatment with nitrosoguanidine for a partial resistance to thymineless death. This strain shows, in addition, a global increase of the RNA content amounting to 50 per cent. The half-life of the unstable RNA as well as of the messenger RNA of the beta-galactosidase is increased to a considerable degree. The RNA polymerase of this strain is modified with respect to its resistance to rifampicin and its transcription efficiency in vitro of various DNA templates. Our working hypothesis is that the primary alteration of this strain lies at the RNA polymerase level with a consequent increase of the synthetic rate of the ribosomal RNA. The increase of the messenger RNA half-life may be an indirect consequence of this event via a saturation of the RNAase by the excess of ribosomal RNAs not associated to their proteins.


The pyridoxal-phosphate-dependent enzymes exclusively catalyzing reactions of beta-replacement.

Theoretic and experimental arguments are surveyed which justify the setting up, within the family of pyridoxal-P-dependent lyases, of a special subgroup that comprizes several enzymes catalyzing exclusively beta-replacement reactions of alpha-aminoacids with electronegative substituents in the beta-position. The authors and their associates have studied the physico-chemical and catalytic properties of four high purity enzymes belonging to this subgroup, namely: cysteine lyase (EC 4.1.1.10) from embryonic chicken yolk-sac, serine sulfhydrase from chicken liver and the closely analogous or synonymic cystathionine beta-synthase (EC 4.4.1.8) from rat liver, and beta-cyanoalanine synthase (EC 4.4.1.9) from lupine seedlings, in comparison with some pyridoxal-P-requiring lyases differing in reaction specificity, for example, gamma-specific, alphabeta-eliminating or plurifunctional lyases such as gamma-cystathionase (EC 4.4.1.1) of animal tissues. The results of these studies, relating to subtrate and cosubstrate specificities of the enzymes mentioned, their interactions with some selective inhibitors, catalysis of isotopic exchange of hydrogen atoms in substrates and substrate analogs, etc., indicate that lyases of the exclusively beta-replacing type substantially differ in reaction mechanism from other subgroups of this enzyme family. Thus, it appears highly improbable that transient formation of an alphabeta-unsaturated, coenzyme-substrate imine, considered as an obligatory step in the action of lyases in the alphabeta-eliminating and other subgroups, should occur in the sequences of reaction intermediates in the case of beta-replacing lyases. Suggested features of the presumable catalytic mechanism of these lyases are discussed, such as : fixed conformation of the aminoacid substrate in the ES complex (protein-bound pyridoxal-P aldimine), with beta-substituent in orientation cis (rather than trans) to the Halpha  atom ; role of the binding of appropriate cosubstrates (nucleophilic replacing agent, Cs) inducing essential electronic and/or steric transitions in the catalytic site of the ternanry CsES complexes, etc.


The periplasmic galactose receptor protein of Escherichia coli in relation to galactose chemotaxis.

The periplasmic galactose receptor protein of E. coli is the common macromolecule in the initiation of two functions, chemotaxis and active transport. The substrates are glucose and galactose and the affinity for binding to the receptor protein is high (Kp -2 X 10(-8) M for glucose and 1 X 10(-7) M for galactose). A second binding site shows a 100-fold lower affinity. The high concentration of the galactose receptor protein in the periplasmic space tends to give retention through recapture of the ligands. The kinetic properties of the galactose receptor protein are, in general, in harmomy with the kinetics of chemotactic responses to spatial or temporal sugar gradients.


[Immobilized antibodies: a possible technic for the epidemiological study of antibiotic resistant bacteria].

An antibody specific to a cephalosporinase responsible for the resistance of bacteria to cephalosporines has been immobilized on agarose beads by the iminocarbonate method. The resin thus obtained has been studied at a biospecific point of view. Its high thermostability is also demonstrated. This biospecific resin allows the performance of epidemiologic experiments of bacteria resistant to beta lactamines.


The methylation of tRNA.

The methylation of tRNA is a post-transcriptional modification which is achieved by specific enzymes, the tRNA methylases, with S adenosylmethionine as a methyl donor. The level and pattern of methylation are characteristic of the tRNA species and origin. Abnormally methylated tRNAs have been obtained, in vivo and in vitro, by a variety of methods, and their properties have been studied. The tRNA methylases are found in all cells and tissues. Their activity varies with the differentiation state of the cells, and under the influence of many internal and external factors ; it is especially elevated in embryonic and cancerous tissues. These enzymes are very unstable, and none of them has been purified to homogeneity. We present here their known properties and we propose a theory concerning their specificity. Finally, after reviewing the few available experimental data, we discuss the current hypotheses and speculations about the roles and functions of tRNA methylation.


Presence of two forms of palmityl-CoA-ACP-transacylase in homogenates of Mycobacterium smegmatis, purification using the monomer-polymer interconvertibility.

Homogenates of Mycobacterium smegmatis have been shown to contain, among other acyl-transfer enzymes, two entities endowed with palmityl-CoA-ACP-transacylase activity (1973, this journal, 55, 1381-1394). The present report demonstrates that these two entities, now called palmityl-CoA-ACP-transacylase I and palmityl-CoA-ACP-transacylase II, following their elution rate from a Sephadex G-150 column, are two interconvertible forms of the same enzyme. Form II, apparently predominant in the crude homogenates, is converted, during the purification steps, into Form I. The latter is convertible into Form II. It is observed that when the concentration of the enzyme increases, Form I becomes predominant. A purification of 800-fold was achieved, particularly by taking advantage of this convertibility properties. Parallel experiments conducted on S. cerevisiae and E. coli homogenates show the presence of the enzyme in the former and its absence in the latter microorganism.


[Transaminase B from Escherichia coli. I.-Purification and first properties].

Transaminase B (EC.2.6.1.6.) from E. coli, the specific enzyme for branched-chain aminoacids, was obtained in a purity equal to or greater than 96 p. cent after an 800-fold purification, employing two different procedures. One of the procedures involved heating at 60degreesC. The apparent molecular weight of the enzyme was estimated by chromatography on Sephadex and gel electrophoresis to be close to 180,000. The protein is made up of 6 subunits of equal size, with one molecule of coenzyme in each. Its absorption spectrum shows bands at 335 and 415 nm, and was found to be almost insensitive to the pH of the medium between 4.6 and 9. Transaminase B is active on phenylalanine as well, although the reaction between L-phenylalanine and alpha-ketoglutarate is about 50 to 100 times slower than the analogous reaction using L-valine as an aminoacid. Three sets of data show that the phenylalanine aminotransferase activity associated with transaminase B is not an artefact due to a protein contaminant. 1) Activities displayed toward phenylalanine and valine cannot be resolved by different methods, including chromatography, gel electrophoresis, and electrofucussing. 2) The absorption spectrum of the enzyme is as strongly modified by phenylalanine as by valine. 3) A ketoglutarate-free reaction between phenylalanine, tyrosine or typtophane and an aliphatic alpha-ketoacid is catalyzed by the pure enzyme and follows a mechanism belonging to the usual ping pong type. The possible significance of this reaction as a regulatory device in the cell metabolism is briefly discussed.


Rib anomalies in myelodysplasia. An approach to embryologic inference.

An embryologic teratogenic mechanism is reconstructed by utilizing the distribution of anomalous ribs in children with lumbosacral myelomeningocele. This methodology may help to coalesce information from experimental models of teratogenesis and from descriptive human embryology. It provides an approach to deductive reasoning about human structural anomalies based on dynamic embryonic models of teratogenesis. Availability of a developmental time scale, based for example on the distribution of defective ribs, may be useful in the study of other teratogenic and developmental processes.


The effects of continuous positive airway pressure on lung mechanics and lung volumes in the neonate.

We have studied the effect of continuous positive airways pressure (CPAP) on the lung mechanics and thoracic gas volumes on 15 occasions in 12 healthy neonates. As expected, the thoracic gas volume rose and total pulmonary resistance fell. The dynamic compliance fell on all occasions. 43% of the applied pressure was transmitted through to the mediastinal structures.


Chemically sensitive field-effect transistors.

The present state of the art and trends in development of chemically sensitive field-effect transistors are reviewed. In the theoretical section, a brief description of principles, temperature sensitivity, stability and the question of a reference electrode are discussed. In the practical section some aspects of the design and recommendations for device evaluation procedures are given. The article concludes with the authors' view of future development, particularly with respect to biomedical applications.


Optimizing the enzyme--labeling of antibody.

Recently developed immunohistochemical techniques allow the biologist to monitor the migration and activity of immunoglobulins via enzymatic labels. This paper proposes a model for the description of this labeling process and investigates the optimum mixture of immunoglobin and label for this model.


Specific immunodiagnosis of human hydatidosis by the enzyme linked immunosorbent assay (E.L.I.S.A.).

The enzyme-linked-immunosorbent-assay (E.L.I.S.A.) using whole and purified hydatid antigens was applied to the diagnosis of human hydatid disease. This sensitive and economical method provides new possibilities for the specific diagnosis of parasitic diseases by automated procedures.


The cellular immune capacity of mice with transplanted lymphoid leukaemia.

Mice bearing transplanted lymphoid leukaemia rejected grafts of allogeneic skin in normal manner. Cells fromtheir spleens, collected in progressive stages of the disease, mounted cellular immune reactions as competently as the spleen cells of normal mice. Radiolabelled leukaemia cells accumulated in graft beds These findings were interpreted as showing that malignant cells of this leukaemia may become recruited to take part in the immune response.


The electrophoretic hemolytic plaque assay -- theory.

We use the mathematical theory of plaque qrowth to determine if there is merit in performing a hemolytic plaque assay in the presence of an external electric field. In particular, we study the effects of an electric field on the transport of antibodies secreted by a single lymphocyte and on the size and shape of the plaques they produce. Our results indicate that in the presence of an applied electric field: (1) The mobility of the antibodies produced by the antibody forming cell can be determined from the plaque shape. (In the electric field the plaques are no longer circular, but cigar shaped.) (2) By changing the magnitude or direction of the applied electric field more than one plaque can be generated by a single AFC. Thus changes in mobility or the rate of antibody secretion can be assayed. (3) Plaques will reach a steady state size; for good emitters (cells that secrete antibodies at a high rate or that secrete high affinity antibodies) this steady state will be achieved rapidly. Equations are given which describe both the temporal development and steady state plaque size and shape. From the equations, computer generated plots of plaques produced by typical antibody forming cells are presented. These plots are then used to show how pictures of plaques formed in an electric field can be analyzed to determine the antibody mobility.


Fed batch culture of Saccharomyces cerevisiae: a perspective of computer control to enhance the productivity in baker's yeast cultivation.

A means to avoid the glucose effect in the production of baker's yeast from glucose and/or molasses in a fed batch culture by controlling the feed rate of fresh medium with an ad hoc measurement of the respiratory quotient, RQ, is presented. The feed rate is changed stepwise here such that the value of RQ ranges from 1.0 to 1.2 throughout the cultivation. Thus far, the specific growth rate based on the total cell mass and the growth yield obtained throughout are 0.24 hr-1 and 0.55 g cell/g glucose. Prior to the experimental run mentioned above, equations to predetermine the feed rate and concentration of glucose in the feed are derived from the mass balance of limiting substrates (glucose). Since values of either RQ or Io2 (Qo2 x, oxygen consumption rate with respect to the total cell mass in the fermenter) can be measured quite easily and reliably, computer control of the fermentation in light of this information is discussed.


Large-scale disintegration of microorganisms by freeze-pressing.

A semicontinuous press has been constructed for the disintegration of microorganisms and other biological material by freeze-pressing, i.e., pressure extrusion of frozen material through a narrow hole. The material to be freeze-pressed is frozen in the form of cylindrical rods, which fit into the pressure chamber and are extruded by a piston forced back and forth by means of a hydraulic pump. At a sample temperature of -35 degrees C and a press temperature of -20 degrees C, about 90% disruption is achieved in a single passage of undiluted baker's yeast (Saccharomyces cerevisiae, 270 mg/g) through the orifice of the pressure chamber. With this press about 10 kg of material can be freeze-pressed per hour.


Corneal transplant for therapy of primary corneal dystrophies.

Penetrating corneal transplants for primary corneal dystrophies such such as keratoconus and Fuchs dystrophy, and for hereditary dystrophies such as granular, lattice, and macular have an excellent prognosis of 95% or more for a clear graft and good vision in the series presented. These dystrophies are rarely associated with corneal vascularization, unless induced by silk sutures, knots of sutures, exudate, or repeated operations. Accordingly, the incidence of homograft rejection is reduced. However, there is a slower rate of healing, especially with nylon sutures which should not be removed for at least six months. The use of steroids, especially with intensive administration topically or over a long period of time, subconjunctival injection of repository forms, or theoretically at least, systemic administration, can be followed by posterior subcapsular lens opacities which may remain stationary if medication is stopped. Unfortunately, within several years the hereditary dystrophies may slowly develop a recurrence of the dystrophy in the graft requiring reoperation.


Retinal vaso-occlusion in sickling hemoglobinopathies.

Sickle cell retinopathy, in all of its manifestations, represents the effects of arteriolar and capillary occlusions. Increased viscosity of circulating whole blood plus the microembolic action of individual sickled erythrocytes contribute to vasoocclusion. Decreased oxygenation and increased acidosis develop and lead to further sickling -- and further vaso-occlusion. The cycle of erythrostasis that characterizes sickling throughout the body is also applicable to the retina. The transparent media of the eye permit direct visualization of vaso-occlusions which occur preferentially in and about the macula and in the far periphery of the retina. Many of the occlusive episodes are transient. There dynamic events are simultaneously occurring elsewhere in the body but can only be visualized in the eye. The net effect in the retina is a remodeling of its vasculature, as some vessels close and others reopen. After the onset of arteriolar closure in the retina, affected blood vessels embark on a spontaneous, naturally evolving course of events leading to arteriolarvenular anastomoses, neovascular proliferations, vitreous hemorrhages, and retinal detachment. The advanced stages of proliferative sickle retinopathy are most commonly observed in SC disease and in Sthal, possibly because these two forms of sickling have significantly higher than normal whole blood viscosity. Retinal vaso-occlusions can also lead to blow-out hemorrhages which may evolve into salmon patches, iridescent spots, schisis cavities, and black sunbursts. In some respects sickle retinopathy is unique, but many of its manifestations are similar to those of retinopathies found in diabetes mellitus, AC hemoglobinopathy, Takayasu pulseless disease, sarcoidosis, chronic myelogenous leukemia, branch retinal vein occlusion, retrolental fibroplasia, and Eales disease.


[Effect of transplantation of lymphoid and bone marrow cells on the immune response following immunization of mouse strains little or highly reactive to the antigen].

C57BL and CBA mice, with low or high reaction to immunization with sheep erythrocytes, respectively, were given transplantation of the syngenous lymphoid or bone marrow cells. Transplantation of the syngenous cells to C57BL mice intensified the production of antibody-forming cells to sheep erythrocytes and depressed it in transplantation to CBA mice. A different effect of transplantation of the lymphoid and bone marrow cells on the immune response, depending on the recipient's genotype, is discussed.


[Importance of the time of bone marrow transplantation for demonstration of allogenic inhibition of sten cells].

The effect of the interval (4-96 hours) between the irradiation of hybrids (CBAXC57BL/6 F1 and the bone marrow transplantation from C57BL/6 mice on the manifestation of allogenic inhibition of the stem cells was studied; in the given donor-recipient model the degree of allogenic inhibition constituted 90%. The bone marrow transplantation 4 to 48 hours after the irradiation failed to influence the number of colonies in the spleen of hybrids F1, but when this transplantation was given 96 hours after the irradiation the colony-forming ability of parental hemopoietic cells regressed to 33%. Remote transplantation had no influence on the number of colonies in the spleen of syngenic recipients.


[Localization in cells of Neisseria perflava and Klebsiella pneumoniae of antigens in common (cross-reacting) with tissues of the human bronchopulmonary apparatus].

A study was made of localization in the cells of Neisseria perflava and Klebsiella pneumoniae of antigens common with the tissues of the human broncho-pulmonary apparatus. A study was made of cross reactions of some structures of Neisseria perflava and Klebsiella pneumoniae cells (capsule, walls, cytoplasmic structure fraction, hyaloplasm) in the complement fixation test with antilung sera. Antigens cross reacting with the antilung sera were localized not only in the surface structures (walls) of bacterial cells, but also in the "deep" components (cytoplasm fraction rich in ribonucleoproteids) of the microbe.


[Insulin concentration in plasma from the femoral, hepatic and pancreatico-duodenal veins of dogs under standard conditions and in corisone glucose tolerance tests].

In comparing the results of glucose tolerance tests conducted against the background of cortisone action and without it the former one proved to have advantages over the latter one in studying the incretory function of the pancreas. A biphasic character of insulin secretion in glucose loading was revealed with the aid of this test. Secretion of insulin by the pancreas was better reflected by the dynamics of insulin content in the blood of the pancreatic-duodenal vein that by the dynamics of its content in the blood of the peripheral veins.


[Mitosis in the tubular epithelium of allotransplanted dog kidney during the early periods following transplantation].

Cells dividing by mitosis were revealed in the tubular epithelium of 5 of 23 allografted kidneys of mongrel dogs. These mitoses were localized in the proximal and distal convoluted tubules (88 and 21 mitoses, respectively). Four pathological mitoses among 29 dividing epithelial cells were revealed 3 and 5 days after the operation, whereas no pathological mitoses were found among 80 mitoses of the kidneys present in the recipient's organism for 1 and 2 days. No mitoses were observed in the tubular epithelium of control kidneys (in the unoperated dogs).


[Age and the functional activity of the pancreatic insular apparatus].

A study was made of age peculiarities of the insular function of the pancreas and of the indices of insuline provision of the organism in rat under conditions of sugar loading. It was shown that, in spite of hyperinsulinemia and a higher rate of insuline release glucose release in old rats became worse; this testified to the development of a relative insuline insufficiency in animals of old age. Hyperinsulinemia in old rats coursed against the background of a decreased total blood insular activity and increased "factor of insulin inactivation". The development of a relative insuline insufficiency in old rats depended on both the insular and the non-pancreatic factors, leading to a decrease of the biological activity of insuline.


[Distribution of colony-forming cells in the bone marrow and spleen of irradiated mice].

Two hours after the transplantation of 2-10(5) bone marrow cells 1.7--2.8% of the colony-forming units (CFU) persisted in the bone marrow and 14--16% -- in the spleen of the recipients. In 24 hours there was 1--2% of the CFU in the bone marrow and 21--26% in the spleen. The "F-factor" for these organs was constant in the recipients (under conditions of saturation) for 24 hours after the transplantation of 2.5.10(6)--1.7--10(7) bone marrow cells. The "F-factor" for the CFU seeding the spleen was 20--22% and for the CFU seeding in the femus--2,4--2,7%. It is supposed that the count of the CFU seeded in the total bone marrow volume was equal to that in the spleen. The average sum of the CFU seeding in the spleen and in the total bone marrow volume was about 40--50%. The fate of other CFU is unknown.


Delayed erythropoiesis in irradiated rats grafted with syngeneic marrow: effects of cytotoxic drugs and iron-deficiency anemia.

Erythropoiesis in spleens of lethally irradiated Lewis rats grafted with 4-35 X 10(6) syngeneic marrow cells was inhibited or delayed during the test period of 5 days; this was in marked contrast to observation in irradiated mice. The mechanism of this inhibition was the subject of this study. Pretreatment of recipients 9 days prior to irradiation with the cytotoxic drugs cyclophosphamide (CY), busulfan (BUS),  or dimethylmyleran (DMM), or the induction of iron deficiency with anemia in recipients reversed this delayed erythropoiesis. However, neither iron-deficiency anemia nor pretreatment with BUS or DMM affected the ability of irradiated recipients to reject 20 to 50 X 10(6) allogeneic marrow cells. The administration of commercial preparations of erythropoietin to hosts stimulated erythropoiesis moderately. However, proliferation of syngeneic marrow cells was not enhanced when infused into lethally irradiated Spontaneous Hypertensive (SH) inbred-strain rats which have high levels of endogenous erythropoietin. Finally, plasma from irradiated rats treated with phenylhydrazine to produce severe anemia was rich in erythropoietin but failed to stimulate erythropoiesis in the cell transfer system. Two hypotheses are considered: (1) Irradiation inhibits the secretion of a factor (not erythropoietin) responsible for initiating early stages in differentiation of transplanted stem cells; iron-deficiency anemia and cytotoxic drugs stimulate the secretion of this factor. (2) Normal rats secrete a factor which suppresses erythropoiesis; iron-deficiency anemia and cytotoxic drugs inhibit the production or function of this factor. Cellular rather than humoral factors may by involved.


The accuracy of radiological and computer dianoses in small bowel examinations in children.

A prospective study has been made of the accuracy of the diagnoses made by radiologists and by two computer methods of prediction in 120 children having radiological examinations of the small bowel. The predicted diagnoses were calculated using the Bayesian and Relative Likelihood techniques. The results have been compared with the final clinical diagnoses, which have been considered to be "correct". It was found that in 94 (78 per cent) children with no small-bowel disease the correct diagnosis was made by the radiologist in 79 (84 per cent), by the Bayesian method in 86 (91 per cent) and by the Relative Likelihood method in 77 (82 per cent) children. In the 26 (22 per cent) children with small-bowel disease the correct diagnosis was made by the radiologist in 21 (81 per cent), by the Bayesian method in 13 (50 per cent), and by the Relative Likelihood method in 11 (42 per cent) children. The accuracy of the three methods of interpretation of signs has been compared using the diagnostic test rating index, which takes into account the false-positive and false-negative results, as well as the correct and incorrect results. The radiologist rating was 0-76, the Bayesian method 0-57 and the Relative Likelihood method 0-51. The index for the radiologist was significantly greater than that for the Relative Likelihood method (p less than 0-05). Computer predictions are based on observations made by the radiologist and may be affected by the initial selection of signs, the compression of information into a "normal" or "abnormal" format, and the size of the bank of information available. They offer an objective test of the significance of selected radiological signs. Computer diagnosis provides a useful research tool, but in this study was less accurate than the radiologist.


Perfusion in the experimental preservation of the rat heart.

Rat hearts have been preserved for 24 hours using four different preservation solutions. The results suggest that the best preservation fluid is Tyrode's solution with Ficoll 5 per cent. A comparison of simple cooling of the heart and perfusion, either continuous or intermittent, has shown that intermittent perfusion of the heart for 2 minutes every 6 hours gives the highest rate of 24-hour preservation.


Bilateral nephrectomy prior to renal transplantation.

Bilateral nephrectomy was performed in 53 patients on regular haemodialysis. The indications were pyelonephritis in 30, polycystic kidneys in 6, glomerulnephritis in 7, uncontrollable hypertension in 9 and horseshoe kidney in 1. In 87 per cent of cases the operation was carried out as a separate procedure prior to transplantation. The mortality was 9 per cent and the postoperative complications included hypotension, clotting of arteriovenous shunts, pneumonia and subphrenic abscess. As a result of our experience we have revised our indications for bilateral nephrectomy which now are pyelonephritis only when associated with persistent bacteriuria or ureteric reflux, polycystic kidneys and uncontrollable hypertension.


A technique for rapid harvesting of cadaveric renal and pancreatic grafts after circulatory arrest.

In several countries, organs for transplantation  cannot be removed from cadaver donors until cardiac arrest has occurred. A technique is described for removal of the kidneys and pancreas in which the whole abdominal contents are freed and reflected so that the retroperitoneal organs lie uppermost. The aorta is opened longitudinally and the relevant arteries are cannulated via their orifices. Cold perfusion of the three organs can usually be initiated 5-15 minutes after cardiac arrest and significant ischaemia is avoided. The full length of the vascular pedicles can be preserved and the dissection of the retroperitoneal organs is greatly facilitated.


Prophylaxis against anaerobic sepsis in bowel surgery.

Sixty-two patients were admitted to a prospective randomized controlled trial to investigate the influence of a prophylactic antibiotic, lincomycin, on anaerobic sepsis following bowel surgery. The incidence of postoperative sepsis was reduced from 45 to 18 per cent (P less than 0-025). Wound infections were reduced from 38 to 12 percent (P less than 0-05). Intra-abdominal or pelvic abscess occurred in 1 of the treated group compared with 3 controls. Septicaemia occurred after operation in 1 patient receiving lincomycin and in 3 of the controls; in 2 of the latter, pure growths of bacteroides were isolated from the blood cultures and 1 of these patients died. Although lincomycin had no influence on the number of patients who developed aerobic postoperative infections, there was a significant reduction in the incidence of sepsis due to bacteroides, which occurred in 10 of the control group compared with 1 in the lincomycin group (P less than 0-005). No patients developed complications attributable to lincomycin, such as pseudomembranous colitis. These data indicate that the genus Bacteroides are important pathogenic organisms and are responsible for postoperative morbidity. Furthermore, anaerobic sepsis can be reduced by appropriate prophylactic antibiotics.


Bacteriological survey of acute appendicitis in children.

A bacteriological study of 110 emergency appendicectomies is reported. In two-thirds of these the appendix was inflamed or gangrenous, and in 45 cases positive cultures were obtained from swabs taken at operation. Bacteroides were found frequently in these swabs and also in those taken from wound infections. Although this study is too small to draw any definite conclusions, it is felt that bacteroides should be considered an important pathogen in appendicitis and should be taken into account in the few ill patients where antibiotic treatment is contemplated. It was also noted that swabs taken from the surface of the appendix itself were more often positive than those from the peritoneal cavity, and this difference apperars to be significant.


Wound infection in a children's hospital.

The operation wounds of 20 per cent of the children operated on in one surgical unit of a children's hospital became infected. Infection was commonest in the newly born operated on as emergencies, 50 per cent of whose wounds became infected. No connection was found between injection and nasal carriage of staphylococci. A possible source of infection in the young may be the umbilicus.


Transplantation of tumour with a kidney graft.

A cerebral glioma discovered by angiography and brain biopsy in a kidney donor was subsequently suspected of being a secondary tumour. By this time a biopsy of one of the transplanted kidneys had shown a clump of malignant cells in a glomerulus. Because of the psychological state of this recipient the transplant was not removed, but the recipient of the second kidney was immediately told of the danger of tumour cell transfer, and underwent nephrectomy. The patient remained well on haemodialysis; multiple sectioning of the kidney showed no signs of tumour. The transplant in the first recipient functioned well until his death, six months after operation. At necropsy undifferentiated tumour was found in the pleura, liver, pelvic peritoneum, and transplanted kidney. All cadaver donors should undergo full laparotomy after removal of the kidneys, particularly those with a high risk of cancer, and a full necropsy should also be performed shortly afterwards to exclude tumour and other unsuspected diseases. Then it is not too late to remove a transplanted kidney should a tumour be found.


Co-trimoxazole in prevention of bacteriuria after prostatectomy.

In a prospective, double-blind trial prophylactic cotrimoxazole produced a highly significant reduction in the incidence of bacteriuria after prostatectomy. Only two out of 38 patients who received the drug developed bacteriuria compared with 19 out of 36 patients on placebo. Klebsiella-Enterobacter spp and coagulase-negative staphylococci were responsible for most infections. Although co-trimoxazole prophylaxis is obviously effective, widespread use might increase the incidence of bacterial resistance.


Immunoglobulin synthesis in the "resting" breast.

Nulliparous women have a greater risk of developing breast cancer than women who have borne children, but so far no functional differences in breast tissue have been reported between parous women and nulliparae. Macroscopically and histologically normal breast tissue was obtained from 74 women of reproductive age during biopsy of benign breast lesions and was examined for the presence of plasma cells by immunfluorescence. Immunoglobulin synthesis was detected by an in-vitro culture technique. Synthesis of IgA was detected in 81% of specimans of IgG in 45%, and of IgM in 3%. IgA synthesis much more intense than IgG or IgM synthesis. Plasma cells containing IgA were seen in 71% of the specimens examined, and 88% of specimens had deposits of IgA in the ductules. The findings were not significantly incluenced by the nature of the condition necessitating biopsy or by oral contraception. Nulliparous women showed no cyclical changes, but among parous women IgA synthesis was more intense during luteal phase of the menstrual cycle. This suggests that after the first pregnancy the breast is more sensitive to progesterone.


Quantitative effects of unsaturated fatty acids in microbial mutants. VI. Selective growth responses of yeast and bacteria to cis-octadecenoate isomers.

The full series of positional isomers of cis-octadecenoate were tested for their suitability in meeting the nutritional requirement for unsaturated fatty acids by mutants of Escherichia coli and Saccharomyces cerevisiae that were unable to synthesize unsaturated fatty acids. Quantitative comparisons of the efficiencies of the various isomers showed a range from 0-48 cells per femtomole for the prokaryotic cells and 0-5 for eukaryotic cells. The delta 5 isomer was much more effective than the delta 6 isomer with the bacterial cells whereas the reverse was true with the yeast cells. In general, isomers containing a cis ethylenic bond between carbons 7 and 12 were able to support extensive growth of either type of mutant. Since all of the various isomers were incorporated into cellular lipids by both types of microorganism, the different efficiencies observed in supporting growth were not a simple reflection of the inability of an acid to be esterified. The differences may reflect the suitability of the resultant esterified product to function as a normal membrane lipid. The contents of various fatty acids in the cellular phospholipids when growth ceases may have a linearly cumulative relationship to the degree of expansion of the acyl chains.


Sensitivty of glucose-6-phosphate dehydrogenase activity to saturated and unsaturated fatty acids.

The effect of a number of saturated and unsaturated fatty acids on purified glucose-6-phosphate dehydrogenase (G6PDH) (EC 1.1.1.49) enzyme of yeast was studied. Saturated and unsaturated fatty acids were found to be strong inhibitors of G6PDH activity, the former being noncompetitive inhibitors and the latter being competitive inhibitors.


Sensitization of effector responses by modification of agonist disposition mechanisms.

Much confusion arises in the field of agonist-effector supersensitivity phenomena due to the often encountered lack of discrimination between agonist disposition mechanisms functioning, in the system under study, as access barriers and as terminating mechanisms. Access barriers limit agonist approach to the receptor region and terminating mechanisms serve to remove agonist from the site of action. The assumption of a quantitative identity in these two functions is not often warranted and the effects inhibition of these processes have on the magnitude of effector responses and on their duration can differ strikingly, both qualitatively and quantitatively.


Blockade of LH-RH induced ovulation in immature rats by LH-RH antiserum.

An in vivo method for the determination of biological potency of luteinizing hormone-releasing hormone (LH-RH) antiserum is described. The procedure involves antiserum blockade of LH-RH induced ovulation in immature rats primed with pregnant mare's serum. A modified method for the induction of LH-RH antibodies in rabbits is also detailed.


Colic as the sole symptom of urinary tract infection in infants.

Urinary tract infection was diagnosed in four infants whose sole symptom was persistent recurrent colic. There were no other clinical abnormalities. Three had abnormal radiologic findings in the urinary tract and one subsequently required nephrectomy. In the two others, radiologic findings were normal after 6 months and 1 year, respectively.


Malaria at the Hospital for Sick Children, Toronto.

The number of immigrants to Canada from countries where malaria is endemic increased sevenfold between 1964 and 1974. From January 1973 through July 1975, 15 cases of malaria were treated at the Hospital for Sick Children, Toronto. The only symptom common to all patients was fever, and it was not always cyclic. For any child with a fever of unknown cause who has been in a region where malaria is endemic within the previous 6 months, a blood smear should be examined for parasites. If the smear is negative even when stained with acridine orange, serologic testing should be performed. Acurrate species identification is important since therapy varies according to the causative organism.


Symptoms and signs of malaria.

In addition to asking their patients about recent foreign travel, Canadian doctors need to be aware of what features to ask about in considering imported illnesses. Of these illnesses, malaria is one of the most common and serious. Because of its cerebral renal, pulmonary and intestinal complications, falciparum malaria must be distinguished from non-falciparum forms. Anyone with a fever who has arrived recently from an endemic area should be tested for malaria. In addition, headache, malaise, myalgias, arthralgias, low back pain, nausea, vomiting, diarrhea or cough should raise suspicion. Malaria should be remembered as a cause of coma. Persons taking any form of drug prophylaxis for malaria are not protected absolutely and those who are semi-immune can become severely ill occasionally.


Beclomethasone dipropionate aerosol in allergic rhinitis.

Treatment with beclomethasone dipropionate aerosol (BDA), 50 mug four times daily in each nostril, was compared with placebo therapy in a double-blind non-crossover trial of 30 matched patients with allergic rhinitis induced by ragweed pollen. The trial was started at the beginning of the ragweed season and continued for 42 days. Response to treatment was assessed from information on daily diary cards, weekly objective measurements of nasal patency and measurement of total eosinophil count (TEC) before treatment and at week 4. Patients in the BDA group had significantly less (P less than 0.05) sneezing, rhinorrhea and nasal stuffiness at 36 days, cough at 10 days and antihistamine consumption at 17 days. There was no significant difference between the groups in eye symptoms, nasal airway inspiratory resistance, maximum inspiratory nasal flow or TEC. Overall comparison with previous pollen seasons by the patients indicated moderate to great improvement in 86% of the BDA group and in 13% of the placebo group (P less than 0.01). Minor side effects were noted by two patients in each group.


Musculoskeletal management of the severely burned child.

Aggressive management of severe burns minimizes contractures and helps to maintain muscle tone, joint function and psychological well-being. The positioning, activity and exercise programs, splinting and bandaging, and skin care of burned children carried out by the burns team at the Hospital for Sick Children, Toronto is outlined.


Methotrexate and citrovorum factor rescue in the management of childhood lymphosarcoma and reticulum cell sarcoma (non-Hodgkin's lymphomas): parolonged unmaintained remissions.

High doses of methotrexate (HDMTX), given in pulse infusions of 3 to 30 mg/kg body weight, were studied in 22 children with non-Hodgkin's lymphoma. Sixteen complete and five partial remissions were observed in 21 patients evaluable for remission induction. The dose of MTX was increased stepwise on consecutive treatments until objective tumor response occured. Citrovorum factor rescue (CFR) was used "on demand" when toxicity started to develop, and routinely after 30 mg/kg of MTX. Twelve patients who had no previous chemotherapy were entered in a Phase II study consisting of remission induction with HDMTX and remission maintenance with monthly HDMTX supplemented with one monthly injection of vincristine and Cytoxan and five days of oral 6-mercaptopurine and prednisone. Eleven patients achieved remissions (eight complete and three partial) with HDMTX and one with surgery and radiation followed by HDMTX. The three partial remissions improved to complete remission during remission maintenance. All 12 were given the maintenance cyclic combination chemotherapy. Seven of the 12 patients entered the unmaintained phase of the study. One patient relapsed 6 months after cessation of therapy and died 4 years after diagnosis. Six patients are alive and free of disease 2 1/2 to 5 1/2 years after discountinuing treatment and 4 1/2 to 8 1/3 years after diagnosis. Five of these six patients had advanced (Stage IV) disease.


Combination chemotherapy of the malignant lymphomas: a controlled clinical trial.

The Eastern Cooperative Oncology Group has studied 113 patients with generalized progressive malignant lymphomas in a randomized clinical trial. Pathologic diagnosis was subclassified by cell type and nodal pattern by The Pathology Panel for Lymphome Clinical Trials. Patients were randomly assigned treatment with either cyclophosphamide (C), vincristine (O), and prednisone (P) (COP) or CO without prednisone. Initial treatment was given for 8 weeks and further randomization of responders to observation or additional chemotherapy was carried out. A significant difference in complete remission rate between treatments was shown: with COP, 43%, and with CO, 17%, indicating an important role for prednisone in inducing CR. COP was also associated with longer remission durations and improved survival. Complete remission following initial chemotherapy is also associated with longer duration of disease-free time and survival. The initial pathologic cell types and nodal pattern also strongly influence survival. Extended "maintainence" CO treatment improved disease-free remission duration, but not survival.


Use of immunohistochemical and morphologic methods for the identification of human growth hormone-producing pituitary adenomas.

Indirect immunoperoxidase and immunofluorescent techniques were used for the detection of growth hormone in routinely processed human pituitary adenomas. With the immunoperoxidase method, distinct immunoreactive cells could be demonstrated in 15 adenomas; all except for one were associated with acromegaly. Immunofluorescence was less useful because of autofluorescence due to the fixation. In histologic stainings, the immunoreactive cells were acidophyl. With immunohistochemistry and electron microscopy, densely granulated and sparsely granulated adenomas could be distinguished. Sparse granulation was associated with an expanded rough-surfaced endoplasmic reticulum and Golgi complex. Clinically, the sparsely granulated adenomas were characterized both by active hormone secretion and aggressive local growth. It is concluded that the immunoperosidase method is of value for functional classification of pituitary adenomas. For information about secretory activity we suggest that electron micrographs of adenoma cells be examined.


Detection of mutagenic activity in human urine using mutant strains of Salmonella typhimurium.

Histidine-requiring mutants of Salmonella typhimurium that can be reverted to prototrophy by a variety of mutagens were used mutagenic activity in the urine of patients receiving chemotherapeutic agents. Patients given cyclophosphamide and BCNU had detectable urinary mutagenic activity over a 24-hour period, with maximal levels occurring 12 to 21 hours after drug injection. Whereas native cyclophosphamide required the presence of a rat liver extract to be mutagenic in the test system, the cyclophosphamide metabolites in the urine were fully active in the absence of added liver extract. Mutagenic activity was detected in only the first voided urine specimen of patients receiving fluorouracil. Patients receiving Adriamycin, methotrexate, Mitomycin C, and low doses or oral melphalan did not have detectable mutagenic activity in their urines. One thousand and ten random urine speciments were screened for mutagenic activity. Only eight had greater than 26 revertant colonies per plate. Four of the eight had received metronidazole (Flagyl) for vaginitis while two others had received chemotherapeutic drugs. We were unable to detect increased mutagenic metabolites in the urine of 43 patients with known malignancies, using the standard assay conditions.


Malignant lymphoma of the skin: a clinicopathologic study of lymphoma other than mycosis fungoides.

The clinical and histopathologic findings in 25 cases of malignant lymphoma of the skin other than mycosis fungoides were reviewed. All patients had skin lesions as a primary manifestation of the disorder, and none had histopathologic evidence of extracutaneous involvement at the time of skin biopsy. The majority of patients had solitary nodules involving the skin of the head and neck region. Twenty-two of the skin biopsy specimens were interpreted as lymphocytic lymphoma, well or poorly differentiated, nodular or diffuse. Only three cases of histiocytic lymphoma (reticulum cell sarcoma) were encountered, and there were no cases of Hodgkin's disease of the skin. Twenty-two patients (88%) subsequently developed extracutaneous lymphoma: the interval from the occurrence of apparently localized skin lesions to involvement of lymph nodes and/or viscera ranged from 6 months of 5 years (mean duration of 21 months). Sixteen patients (64%) died of disseminated lymphoma, with survivals that ranged from 8 months to 12 years (mean survival of 3.7 years). Only three patients survived without disease for greater than 1 year. There was no definite relationship between either the histologic subtype of the tumor or the mode of therapy and prognosis. The patholoic findings indicate that a definite diagnosis of malignant lymphoma can be made by skin biopsy in patients with disease apparently confimed to the skin. Careful, detailed examination of the skin biopsy specimen provides a basis for distinguishing malignant lymphoma from cutaneous lymphoid hyperplasia. The clinical findings and survival data support the conclusion that malignant lymphoma with skin lesions as a primary manifestation almost invariably disseminates to extracutaneous organs and usually has a fatal outcome.


The demonstration of carcinoembryonic antigen in colorectal carcinoma and colonic polyps using an immunoperoxidase technique.

Carcinoembryonic antigen (CEA) has been demonstrated in tissues, by immunofluorescence, with conflicting results. Originally thought to be persent in colorectal carcinoma only, the antigen was later demonstrated in inflamed colonic mucosa and polyps. Using formalin-fixed, paraffin-embedded tissues and an immunoperoxidase technique, we have attempted to demonstrate CEA in 12 colorectal carcinomas, in adjacent benign mucosa, and in 42 polyps of varying histologic type. CEA was demonstrated in all colorectal cancers but not in adjacent inflamed mucosa. The antigen could not be demonstrated in polyps except in five cases where CEA was shown in morphologically atypical glands only. With out technique, the demonstration of CEA is a reliable indicator of malignant change in colonic mucosa. The findings in polyps tend to support the concept of carcinoma in situ in adenomatous polyps and the polyp-cancer sequence.


Regression of rat mammary tumors effected by a gonadoliberin analog.

A synthetic analog of gonadoliberin (gonadtropin-releasing factor of luteinizing hormone/follicle-stimulating hormone-releasing hormone), designated A-43818, was evaluated for its ability to effect regression of carcinogen-induced mammary tumors in the Sprague-Dawley rat. This analog, specifically (D-leuyl6, desglycyl-NH210, prolyl ethylamide9), gonadoliberin, is a potent synthetic luteinizing hormone/follicle-stimulating hormone-releasing hormone at low dose levels but, at the higher dose levels used in these studies, the effect appears to be that of a potent gonadoliberin antagonist. Administration of 5 or 20 mug of A-43818 per day to tumor-bearing rats was essentially as effective as ovariectomy in causing mammary tumor regression. At least 80% of the tumors in the A-43818-treated animals underwent regression; about one-half of the regressing tumors disappeared in the 6-week period of continuous treatment, and, unlike the 0.9% NaCl solution control group, no new tumors appeared during the treatment period. A subsequent 4-week period of drug withdrawal resulted in the regrowth of palpable tumors and the appearance of new tumors, most of which again regressed on further A-43818 administration.


Nitrosoureas: a review of experimental antitumor activity.

The chemical class of drugs known as the nitrosoureas are a recently developed group of very active alkylating-agent anticancer drugs which are best represented by BCNU, CCNU, and methyl-CCNU (meCCNU). The nitrosoureas are among the most active, if not the most active, anticancer drugs both quantitatively (log kill of sensitive tumor cells in vivo) and qualitatively (spectrum of mouse, rat, and hamster tumors responding to treatment). Therapeutic anticancer activity of the nitrosoureas has been consistently observed with oral as well as parenteral administration. The nitrosoureas are clearly the most active group of anticancer drugs observed against experimental meningeal leukemias and intracerebrally implanted transplantable primary tumors of central nervous system origin (eg, gliomas, ependymoblastomas, and astrocytomas in mice and hamsters). The nitrosoureas have been observed to be less than additive in lethal toxicity for vital normal cells in the mouse in combination with representatives of the other major classes of anticancer agents, eg, purine antagonists, pyrimidine antagonists, inhibitors of DNA polymerase(s) or ribonucleotide reductase(s), mitotic inhibitors, drugs that bind to or intercalate with DNA, and other alkylating agents. Therapeutic synergism against one or more transplantable or spontaneous tumors of mice, rats, or hamsters with one of several nitrosoureas in two-drug combinations with representatives of most of the major classes of anticancer agents listed above has been reported. With a number of advanced-stages mouse tumors, generally considered to be refractory to treatment with most anticancer agents, long-term cures have been obtained with combination-drug or combined-modality (surgery plus chemotherapy) treatment. The demonstrated lack of cross-resistance of several leukemias and solid tumors of mice selected for resistance to BCNU, meCCNU, or other alkylating agents suggests that the widely held opinion that all alkylating agents are very similar in biologic mechanism of action, and therefore resistance to one alkylating agent probably predicts cross-resistance to all alkylating agents, may no longer be tenable. If not, then alkylating-agent drug combinations, either used alone or combined with other treatment modalities (eg, surgery) which have been reported to result in therapeutic improvement in a number of experimental murine tumor systems, may be indicated for serious consideration as surgical adjuvant chemotherapy by surgeons or as primary therapy by medical oncologists.


Nitrosoureas in the management of disseminated malignant melanoma.

Three of the nitrosoureas, BCNU, CCNU, and methyl-CCNU, have displayed significant antitumor activity in patients with disseminated malignant melanoma with none clearly superior to the others, although direct comparison in clinical trials was not accomplished. Response rates to various combinations of these nitrosoureas seem a bit higher, but not dramatically so, when compared to the single-agent response rates, although again this cannot be stated with certainty since direct comparisons were not accomplished. There appears to be no therapeutic advantage to the utilization of any one of the nitrosoureas over the others, but oral administration, as is available for CCNU and methyl-CCNU, is a distinct advantage to the patient and to the clinician. The response rates are, for the most part, rather consistent for the various studies reported in this paper, and these response rates leave a great deal of room for improvement. Secondary therapy utilizing the nitrosoureas was singularly unsuccessful in most of the reported clinical trials. It is refreshing, however, to have agents which have shown activity, although modest, in this most refractory of neoplasms.


BCNU (NSC-409962) in the treatment of advanced Hodgkin's disease: its role in remission induction and maintenance.

BCNU is an effective antitumor agent in the treatment of Hodgkin's disease. Forty-seven percent of a group of patients with advanced disease, refractory to combination or sequential-agent chemotherapy, achieved an objective response to BCNU. Bone marrow toxicity was delayed in onset and was dose related. When incorporated into a maintenance program after remission induction with combination chemotherapy, BCNU appeared to delay, but not ultimately prevent, relapses during a 2-year followup period. Toxic effects associated with BCNU maintenance therapy in this clinical situation were significantly greater than toxic effects associated with no maintenance therapy.


Nitrosoureas: useful  agents for the treatment of advanced gastrointestinal cancer.

Patients with a wide range of gastrointestinal cancers have been treated with nitrosoureas by the Eastern Cooperative Oncology Group. Methyl-CCNU, CCNU, and streptozotocin have been evaluated as single agents in the treatment of colorectal carcinoma. Methyl-CCNU has had an extensive trial in gastric carcinoma as a single agent and in combination with 5-fluorouracil (5-FU). It has also been used to treat pancreatic carcinoma and, in a few patients, carcinoma of the biliary tract. In gastric cancer it would appear that a synergistic effect on response rates has resulted from the combination of methyl-CCNU and 5-FU. The addition of cyclophosphamide to this combination as an induction agent detracted significantly.


Southeastern Cancer Study Group trials with nitrosoureas in Hodgkin's disease.

A decade of studies with the nitrosoureas in the Southeastern Cancer Study Group has shown that they are active agents for the treatment of Hodgkin's disease and that they may be combined with other chemotherapeutic agents in regimens which have acceptable toxicity to produce excellent response rates. Further more, six monthly cycles of treatment with a combination of either BCNU, vinblastine, cyclophosphamide, procarbazine, and prednisone or mechlorethamine, vincristine, prednisone and procarbazine(MOPP), following the achievement of a clinical CR, produce significantly superior durations of remission and survival in previously untreated patients. Our studies with BCNU given orally have indicated that it is not a clinically useful drug. Finally, studies with methyl-CCNU given orally have indicated no particular place for this agent in the treatment od Hodgkin's disease when compared to CCNU and BCNU.


Nitrosoureas in multiple myeloma.

A number of cooperative-group and single-institution studies have shown that BCNU used in combination with prednisone alone or with melphalan,cyclophosphamide, and prednisone is useful for remission induction in patients with previously untreated multiple myeloma. In this setting, results with BCNU (and probably CCNU) are as good as (but not superior to)the results obtained to the frequency of remission induction, duration of remission, and survival. BCNU plus prednisone also appears to be equal to melphalan plus prednisone for remission-maintenance therapy, although it is still unclear whether maintenance therapy is superior to discontinuation of therapy during remission. At the present time, the major use of the nitrosoureas in multiple myeloma appears to be for patients who enter remission with conventional alkylating-agent therapy and later relapse. BCNU and CCNU are occasionally effective when used as single agents or in combination with other alkylating agents for relapsing patients. Results of a pilot study at the University of Arizona with low doses of BCNU and adriamycin for patients relapsing on alkylating-agent therapy have been encouraging, with a 54% (seven of 13 patients) incidence of CRs and PRs. The use of this combination in conjunction with vincristine and prednisone for relapsing patients is under investigation by the Southwest Oncology Group.


Hemodynamic effects of acute digitalization several months after acute myocardial infarction.

Left ventricular function was investigated at rest and during exercise by heart catheterization in 15 patients 3-5 months after acute myocardial infarction. The effect of 1 mg digoxin i.v. in ten patients was correlated to placebo (saline solution) in five patients. A significant decrease of the left ventricular enddiastolic pressure, increase of left ventricular systolic ejection fraction and a shift of the left ventricular function curve to left upwards was found after digoxin with no changes in the placebo group. This beneficial effect of acute digitalization in patients convalescing from uncomplicated myocardial infarction without clinical signs of manifest heart failure could have therapeutic implication.


'Wavy' myocardial fibers in spontaneous and experimental adrenergic cardiopathies.

Wavy myocardial fibers, especially when associated with focal edema, are a characteristic sign of acute myocardial ischemia. 'Waving' might be induced by the increased hydrostatic pressure of interstitial edema, which squeezes and stretches the neighboring fibers. Beside their regular occurrence in early myocardial infarcts, wavy myocardial fibers are also frequently encountered in cases of acute adrenergic heart injury, especially in fatal cranial trauma and after injection of high doses of catecholamines in experimental animals.


Evaluation of single plane angiography for left ventricular volume in the intact dog.

Technique and errors of quantitative single plane ventriculography (SPV), and the methods of Dodge and Sandler (Dodge et al, 1962; Sandler and Dodge, 1968) and Greene et al (1967) for determining left ventricular (LV) volume by SPV were evaluated in the intact dog. Stroke volume (SV) and cardiac output (Q) by ventriculography were compared with those obtained by the Fick and dye dilution methods, and their combination. The end-diastolic (EDV) and end-systolic volume (ESV) corrected by appropriate regression equations, the SV (SV=EDV - ESV), and the ejection fraction (EF) were: Dodge and Sandler, 2.26 1.35, 0.91 ml/kg, and 0.42; Greene et al, 2.41, 1.50, 0.91 ml/kg, and 0.39. Using adequate methods, accurate correction for x-ray image magnification, and the appropriate regression equations the standard error of LV volume calculation by single plane radiography, due to unavoidable technical inaccuracies, should not exceed 10% for a single measurement and 5% for the average of two or more successive cardiac cycles. The systematic overestimation of LV volume inherent in ventriculography, and caused by the addition of contrast medium, should not exceed 5% of the true value.


Analog computer assisted beat-by-beat measurement of stroke volume and related variables in man.

A technique for the beat-by-beat measurement of stroke volume is described. Aortic blood velocity signals are obtained from a catheter-mounted electromagnetic velocity transducer and analysed by a purpose-built analog computer. The stroke volume is computed by integration of each period of systolic forward flow using the velocity signal as its sole input. Automatic compensation of flowmeter drift is incorporated and inappropriate triggering of integration by diastolic artefact is prevented by applying both amplitude and duration criteria for the recognition of systolic forward flow. Early diastolic reverse flow is excluded from integration. The cardiac output, mean aortic flow per beat, and interbeat interval are also computed from the velocity signal. With aortic pressure as an additional input signal the mean arterial pressure per beat and systemic vascular resistance can be computed. The computer outputs are calibrated by a manual method. Preliminary studies comparing values for the cardiac output measured by this system and the direct Fick technique have indicated an excellent correlation between the two methods.


Ultrastructural immunocytochemical localization of luteinizing hormone-releasing hormone (LH-RH) in the median eminence of the guinea pig.

LH-RH was localized at the ultrastructural level in axons and nerve terminals of the median eminence of the male guinea pig. LH-RH positive neuronal profiles were most concentrated in the medial-dorsal aspect of the infundibular stalk and in the post-infundibular median eminence at the level immediately following separation of the stalk from the base of the brain. LH-RH containing axon profiles were most abundant in the palisade zone; nerve terminals in contact with the hypophysial portal vasculature were relatively rare. The hormone was present within granules that measured 900-1,200 A in axons of the palisade zone and 400-800 A in nerve terminals abutting on the portal plexus. The differently sized granules represent heterogeneous populations.


Uteroglobin in the rabbit. I. Intracellular localization in the oviduct, uterus, and preimplantation blastocyst.

The localization and release of uteroglobin (UGL) were investigated immunohistologically in the oviducts and uteri of female rabbits from oestrus through the 7th day post coitum and the blastocyst on the 7th day post coitum. UGL was detected within Fallopian tube cells even during oestrus. Granules of UGL appeared toward the bases of these cells. Subsequently, the cells became almost entirely filled with UGI. Drop-like protrusions of the apical cytoplasm suggest a mechanism of apocrine extrusion. All stages of filling and extrusion were visible during the entire preimplantation period. During oestrus, synthesis of UGL within uterine cells becomes sufficiently advanced so that extrusion has either already begun or is about to begin. UGL positive material first appears in the supranuclear regions. Later the entire cytoplasm shows a positive reaction. An uneven distribution of UGL cells is observed in the endometrium. Since only the glands adjacent to the myometrium and cells of the cavum epithelium contain UGL, a striking mosaic of UGL positive and negative cells results. The present report is the first detecting UGL in single cells of the blastocyst. Both entodermal and ectodermal cells proved to be UGL positive. The synthesis and section of UGL in the oviduct and uterus and the possible origins of UGL in the blastocyst are discussed.


Uteroglobin in the rabbit. II. Intracellular localization in the uterus after hormone treatment.

Rabbit uterine uteroglobin (UGL) was studied by electrophoretic and immunological methods following normal copulation, after ovariectomy and progesterone treatment, 17beta-oestradiol and combined progesterone treatment, 17 beta-oestradiol treatment alone and after HCG-induced pseudopregnancy. Electrophoretic studies show the amount of ULG in uterine secretions, the immunological investigations indicate the intracellular localization of ULG and the distribution of ULG-positive cells in the endometrium. No obvious differences were found between the uteri 7 days after injection with chorion-gonadotropin and those 7 days following normal copulation. No differences could be domonstrated between the uteri of animals 35 days following ovariectomy and subsequent progesterone treatment on Days 31-33 and those of normal 7 d. post coitum (p.c.) animals. Uteri from animals treated with progesterone on Days 2-5 p.c. contained more ULG-positive cells than controls. 17beta-oestradiol treatment with and without subsequent progesterone treatment resulted, in both gravid and ovariectomized animals, in the formation of a tall columnar endometrial epithelium. Treatment with 17 beta-oestradiol on Days 1 and 2 p.c. led to a decrease in the number of UGL-positive cells at 7 days p.c. Even after ovariectomy with 17 beta-oestradiol substitution, UGL-positive cells were still present in the endometrium. However a secretion of any magnitude could not be detected. The importance of differentiation between synthesis and secretion (= release) as distinct phases of the glandular response is especially emphasised by the latter findings.


Transfer RNA genes between 16S and 23S rRNA genes in rRNA transcription units of E. coli.

We have identified genes for tRNAGLU/2 on the transducing phages  o80d3ilvsu7+ (see Ohtsubo et al., 1974) and lambdarifd18 (Kirschbaum and Konrad, 1973), and a gene for tRNAlle/1 on the transducing phage o80rifr (Konrad, Kirschbaum, and Austin, 1973). All these phages have previously been shown to carry genes for rRNA (Ohtsubo et al., 1974; Lindahl et al., 1975; Jaskunas et al., 1975a). We have analyzed the position of these tRNA genes by hybridizing purified RNAs to restriction fragments of the phage DNA. The tRNA genes are located inside the rRNA transcription unit in the spacer region between the 16S and 23S rRNA genes.


Synthesis of ribosomal RNA in E. coli: analysis using deletion mutants of a lambda transducing phage carrying ribosomal RNA genes.

Transducing phage lambdarifd18 carries on rRNA transcription unit containing genes for 5S, 16S, and 23S rNAs and also tRNAGlu/2. Mutants were isolated from this phage that carry deletions removing various amounts of the distal end of this transcription unit. These deletions were physically mapped on the lambdarifd18 phage genome. Synthesis of rRNAs and of tRNAGlu/2 was examined in ultraviolet-irradiated E. coli cells infected with lambdarifd18 or with various deletion mutants. It was observed that mutant phages in which the distal end (the 5S rRNA gene and a part of the 23S rRNA gene) of the rRNA transcription unit is deleted can still synthesize both 16S rRNA (or its precursor) and tRNAGlu/2. Apparently, the post-transcriptional cleavage that produces these RNA molecules does not require the presence of the entire transcription unit, that is, it can take place without the complete structure of the transcript ("30S pre-ribosomal RNA"). In addition, the experimental results support the gene order, 16S rRNAGlu/2, 23S rRNA, and 5S rRNA genes, in the rRNA transcription unit carried by lambdarifd18.


A temperature-sensitive suppressor enabling the manipulation of the level of individual proteins in intact cells.

A temperature-sensitive suppressor strain of E. coli has been isolated and characterized. The properties of the mutant indicate a strong potential for its use in biochemical and genetic work. In particular, the mutant makes possible the variation of the intracellular concentration of selected protein, permitting an evaluation of its role in cell growth and biochemistry. The mutant also permits the selective radiochemical labeling of proteins in vivo for in vitro identification and analysis. The utilization of the mutant for these and other applications is discussed.


Adjacent repeating units of Xenopus laevis 5S DNA can be heterogeneous in length.

The distribution of length heterogeneity in adjacent repeating units of X. laevis 5S DNA has been examined by "cloning" 5S DNA in bacteria. Fragments of 5S DNA produced by partial digestion with Hind III and containing 1, 4, and 5 repeating units have been inserted at the single Hind III site of the tetracycline-resistance plasmid, pSC101, and the hybrid plasmids cloned in E. coli. Adjacent 5S DNA repeats in the cloned multi-repeat fragments can differ in length. This finding rules out some mechanisms which have been proposed to account for the parallel evolution of tandem repeated DNAs. The results are consistent with an unequal crossing-over mechanism and place some constraints on the molecular processes in this recombinatory event.


The structures and fidelity of replication of mouse mitochondrial DNA-pSC 101 EcoRI recombinant plasmids grown in E. coli K12.

Recombinant DNAs containing the E. coli plasmid pSC101 and mouse cell (La9) mitochondrial DNA (mtDNA) were formed in vitro via ligation of DNA fragments from limit EcoRI endonuclease digests and were used to transform E. coli K12. Four structurally different recombinant plasmid DNAs from transformed clones were characterized. Two of these were analyzed extensively and the mtDNA portions compared with mtDNA from LA9 cells. No differences were detected in the physical or chemical properties examined, except that the E. coli mtDNA lacked the alkali lability characteristic of animal mtDNAs. Heteroduplexes between the LA9 portions of the recombinant plasmids and LA9 mtDNA were analyzed by absorbance melting. The melting temperatures were indistinguishable from reannealed LA9 mtDNA homoduplexes, indicating that single-base replication errors occur at a frequency of fewer than 1 nucleotide in 300. Electron microscopic analyses of plasmid-LA9 mtDNA heteroduplexes and a comparison of agarose gel electrophoresis of restriction endonuclease fragments also indicated no differences. These results were independent of the order or the relative orientation of the pSC101 and mtDNA fragments. A third EcoRI fragment in LA9 mtDNA, not found in an earlier study (Brown and Vinograd, 1974), has been positioned in the LA9, EcoRI map. This fragment contains 165+/-10 nucleotide pairs.


The relationship between group C adenovirus tumor antigen and the adenovirus single-strand DNA-binding protein.

The group C adenoviruses code for a single-strand specific DNA-binding protein of molecular weight 72,000 daltons which is synthesized at early times after productive viral infection. Experiments were designed to determine whether this single-strand specific DNA-binding protein was expressed in adenovirus tumors and transformed cells. Two independently derived preparations of anti-sera from hamsters bearing group C adenovirus tumors were tested for antibody against the single-stranded DNA-binding proteins. One antiserum contained antibodies that reacted with these DNA-binding proteins, while the second antiserum did not contain detectable levels of antibody. Five adenovirus type 2 transformed rat cell lines were tested for the presence of the single-stranded specific DNA-binding proteins. Two of the five transformed cells expressed detectable levels of this protein. These results indicate that the group C adenovirus single-strand specific DNA-binding proteins are expressed in some, but not all, adenovirus tumors and transformed cell lines. Those transformed cell lines (type 2) containing a portion of the adenovirus genome designated by the Eco R-I-B restriction enzyme fragment express the single-strand specific DNA-binding proteins. Those cell lines missing this Eco R-I-B fragment do not contain this viral protein. Other experiments have located the structural gene of the signle-strand specific DNA-binding protein in the Eco-R-I-B DNA fragment, indicating that when this gene is present in a transformed cell, it is expressed.


Effect of the RelA gene on the synthesis of individual proteins in vivo.

We have shown that the relA gene can affect the rates of synthesis of many nonribosomal proteins in E. coli. We used rel+ and relA strains that contain a temperature-sensitive valyl tRNA synthetase. Upon transfer from a permissive temperature (30degreesC) to a semi-resitrictive one (36.5degreesC), these strains continue to grow, although undergoing a partial deprivation of valyl tRNA, In the rel+ strain, the concentration of ppGpp increases immediately, and the accumulation of RNA ceases abruptly but temporarily. In contrast, in the relA strain, the concentration of ppGpp falls, whereas the rate of accumulation of RNA increases. As judged by gel electrophoresis, the rates at which individual polypeptides are synthesized by the strains after their transfer to 36.5degreesC depend to a large extent upon the allelic state of the relA gene. In both strains, the concentration of ppGpp changes soon enough to have altered the synthesis of some of the proteins by affecting the transcription of their genes.


Identification of genes for elongation factor Ts and ribosomal protein S2 in E. coli.

The structural gene for elongation factor EF-TS (tsf) and that for ribosomal protein S2 (rpsB) have been identified in E. coli. Both genes are carried by lambda transducing phages that have been isolated as dapD+polC+ transducing phages. Synthesis of both S2 and EF-Ts was demonstrated in ultraviolet light-irradiated E. coli cells infected with these phages. Experiments were also done using other transducing phages that carry dapD+ but not polC+. The data indicate that both the tsf and rpsB genes map near dapD at about 4 min on the E. coli genetic map. This location is different from the two chromosomal locations, the str-spc region and the rif region, where many ribosomal protein genes, the genes for RNA polymerase components, as well as other elongation factor genes (fus, tufA, and tufB) are located.


Nucleosome structure in Aspergillus nidulans.

The structure of chromatin from Aspergillus nidulans was studied using micrococcal nuclease and DNAase I. Limited digestion with micrococcal nuclease revealed a nucleosomal repeat of 154 base pairs for Aspergillus and 198 base pairs for rat liver. With more extensive digestion, both types of chromatin gave a similar quasi-limit product with a prominent fragment at 140 base pairs. The similarity of the two limit digests suggests that the structure of the 140 base pair nucleosome core is conserved. This implies that the difference in nucleosome repeat lengths between Aspergillus and rat liver is caused by a difference in the length of the DNA between two nucleosome cores. Digestion of Aspergillus chromatin with DNAase I produced a pattern of single-stranded fragments at intervals of 10 bases which was similar to that produced from rat liver chromatin.


Cell surface myosin in cultured fibroblasts.

The surface components of L-929 mouse fibroblast cells in monolayer culture have been labeled with 125I by lactoperoxidase-catalyzed iodination procedure. One of the membrane proteins iodinated has been shown to be myosin as follows: it has the same electrophoretic mobility (molecular weight 200,000 daltons) as myosin heavy chain on sodium dodecylsulfate polyacrylamide gels and the labeled myosin is specifically precipitated by fibroblast myosin antiserum from a preparation of purified plasma membrane that have been solubilized by treatment with 1% Triton X-100. One other 125I-labeled membranes protein (molecular weight 210, 000 daltons) is precipitated along with myosin; the latter does not combine directly with antimyosin antibody. This was determined by reacting polyacrylamide gels containing the separated membrane proteins with fibroblast myosin antiserum; myosin was the only membrane protein reacting with the antibody as determined by two separate methods. Membrane myosin is not labeled when the cells are grown in 14C-D-glucosamine or treated with galactose oxidase and potassium borotritide. Thus membrane myosin is probably not a glycoprotein.


In vitro processing of E. coli tRNA precursors.

Using E. coli tRNA precursors isolated from an RNAase P mutant strain, we have studied the steps required for the formation of tRNAs having a mature primary sequence in vitro. Our results suggest that at least three different enzymatic activities can participate in the processing of tRNA precursors.


Multiple modes of ribosomal RNA transcription in vitro.

The rate of rRNA synthesis from E. coli DNA in vitro can exhibit an unusual temperature dependence. Instead of the typical sigmoid curve, at least five to six pronounced peaks of rRNA synthesis are detectable over a 30degrees range in temperature. rRNA synthesis from performed initiation complexes exhibits a similar pattern and shows that the number of polymerases able to initiate rRNA synthesis increases with each successive peak. These results are interpreted in terms of a model which proposes that the rRNA cistrons are served by multiple promoter sites (subpromoters) whose activation energies form a graded series. Thus the number of polymerases initiating rRNA synthesis could be controlled by regulating the number of active subpromoters.


Effect of nitrofurazone on bacterial RNA and ribosome synthesis and on the function of ribosomes.

Exposure of E. coli B/r to nitrofurazone strongly inhibits the synthesis of all classes of RNA and both ribosomal sub-units. Polysome formation is likewise inhibited. However, in E. coli nfr-207 a mutant of B/r which lacks nitrofurazone-reductase I, the synthesis of RNA, ribosomal sub-units and formation of polysomes are not significantly affected. This result implies that a reduced metabolite of the drug rather than the drug itself is the active agent. The ability of ribosomes isolated from nitrofurazone-treated E. coli B/r to carry out poly-U directed polyphenylalanine synthesis was lower than that of ribosomes from untreated cells. 14C from labelled nitrofurazone was found to bind to ribosomal sub-units.


Role of substrains in persistent lymphocytic choriomeningitis virus infection.

Two plaque-type mutants, a wild strain MB(1), and a slow-growing non-plaque-forming variant of LCM virus were compared in L cell cultures. The cultures were monitored at biweekly intervals following infection for plaque-forming virus titre and cytoplasmic and membrane specific immunofluorescence of the cells. Different patterns were obtained in each case and the relevance of these results to LCM persistence is discussed. While the LM variant continually produced virus for 35 transfers, with a cycling titre, the SC variant stopped producing detectable virus after 30 transfers. Thereafter this culture remained fluorescent and resembled the one infected with the slow-growing variant. The degree of specific immunofluorescence of both continued to cycle. The MB(1) strain stopped producing virus after the 18th transfer.


Laboratory diagnosis of lymphocytic choriomeningitis.

Current laboratory methods for the diagnosis of lymphocytic choriomeningitis are discussed, mainly from the point of view of recent improvements. The use of sentinel guinea-pigs is suggested for the detection of lymphocytic choriomeningitis infection in animal colonies.


Lassa fever: review of epidemiology and epizootiology.

The basic ecology of Lassa fever appears to involve enzootic transmission of virus in commensal populations of a single murine species, Mastomys natalensis. Virus may spill over from the rodent cycle to man by various routes. Secondary spread between humans may occur within domiciliary groups, and persons infected within the community who develop clinical disease may introduce the virus into hospital and begin a cycle of nosocomial infection.Between 1969, when Lassa fever was first described, and June 1975, the disease was recognized on 9 discrete occasions, affecting 114 persons. Over one-third of these infections were acquired by person-to-person spread within hospitals. In only one outbreak (in Sierra Leone) were the majority of cases acquired in the community. Recent observations have indicated hyperendemic disease in eastern Sierra Leone. Cases have occurred in Nigeria, Sierra Leone, and Liberia, and serological evidence exists for activity of the virus elsewhere in West and Central Africa. Seasonal factors appear to play a role in the appearance of human cases. Attack rates have been higher in adults than in children. The source of infection and potential routes of virus transmission in the various epidemics are discussed, and perspectives for future epidemiological research are presented.


The three-dimensional dynamic geometry of the left ventricle in the conscious dog.

The dynamic geometry of the left ventricle was assessed with the use of chronically implanted pulse-transit ultrasonic dimension transducers. The orientation of the transducers allowed the measurement of left ventricular minor and major axis diameters and equatorial wall thickness in the conscious dog. The left ventricle was modeled as a three-dimensional, prolate ellipsoidal shell. Left ventricular and pleural pressures were measured with high fidelity micromanometers. Aortic blood flow was obtained with electromagnetic flow probes. To test the assumptions inherent in this technique, left ventricular mass, internal volume, stroke volume, and peak aortic flow were computed from the dimension data and compared to directly measured values. Correlation coefficients of 0.95 or greater were obtained for each of these comparisons. In addition, the calculated left ventricular mass was constant to within +/- 6% of the mean value throughout the cardiac cycle. We found that the dynamic contraction pattern of the left ventricle was dependent on the physiological state of the dog. Furthermore, in the conscious state, shortening of the minor axis diameter, lengthening of the major axis diameter, and slight thickening or thinning of the wall were noted during isovolumic contraction (isovolumic ellipticalization pattern). In the open-chested, anesthetized state, however, marked rearrangements in geometry were observed during isovolumic contraction manifested by lengthening of the minor axis diameter, and significant thickening of the wall (isovolumic sphericalization pattern). We also observed that left ventricular volume was significantly diminished in the open-chested state. The isovolumic contraction pattern in open-chested dogs could be changed from sphericalization to ellipticalization by increasing end-diastolic volume with the infusion of saline. During a vena caval occlusion in the conscious state, the contraction pattern changed from isovolumic ellipticalization to isovolumic sphericalization as the end-diastolic volume decreased. Thus, the exact pattern of left ventricular contraction was found to be a function of left ventricular volume.


Automatic quantitative radiometric assay of bacterial metabolism.

In a two-compartment scintillation vial, suspensions of bacteria were cultured with 1 muCi of [U-14C] glucose and the released 14C02 was measured continuously, cumulatively, and automatically in a liquid-scintillation counter modified to maintain sample temperature at 37 degrees C. We could follow the metabolism of bacterial populations through their early phase of exponential growth with good precision. The data were obtained conveniently, with use of conventional reagents, glassware, and counting equipment. From analysis of the exponential portion of the curves for cumulative activity vs. time, we could measure cell replication rate precisely in units of time. The resulting values were demonstrably independent of some common experimental variables, including the number of bacteria in the inoculum and counting system sensitivity. Sensitivity of the bacteria to antibiotics was measured to within a few percent by noting the relative prolongation of replication time in the presence of those inhibitors. The digital data from the scintillation counter are susceptible to on- or off-line computer analysis, thus providing the prospect for a totally-automated analytical system. The method shows promise for the mechanized quantitative analysis of bacterial growth, and its inhibition.


Behaviour problems in children.

Recent clinical and epidemiological studies of the nature and incidence of behaviour problems in various groups of children are reviewed and the effects of adverse environmental conditions on their development are discussed. Research into the treatment of deviant behaviour by means of behaviour modification techniques is outlined and topics for further investigation are indicated.


An artefact in lactate dehydrogenase isoenzyme patterns, assayed by fluorescence, occurring in the serum of patients with end-stage renal disease requiring maintenance haemodialysis.

In patients with end-stage renal disease requiring maintenance haemodialysis we have observed that serum albumin becomes fluorescent (excitation 356 nm, emission above 405 nm). This fluorescence is detected in the fluorescent assay of lactate dehydrogenase (LDH) isoenzymes on thin-layer agarose creating the impression of an additional LDH isoenzyme anodal to LDH1. This artefact disappears, or is much reduced, following successful donor kidney transplantation. It is not seen in any other pathological condition. This phenomenon can readily be detected by means of "blank" assays on the agarose plates after specimen application and after electrophoresis of the specimen without the substrate overlay.


Potentiation of T-cell mediated immunity by levamisole.

Cell-mediated immunity is a requirement for recognition and elimination of cells and for prevention or treatment of a variety of diseases. Therefore, the development of a product potentially active in increasing immunity involves its testing in assays specific for cell-mediated immunity. The effectiveness of a single administration of levamisole was demonstrated in the rejection of isografts in a male to female C57BL/6 system, and on the enhancement of levels of the delayed type hypersensitivity (DTH) to sheep red cells (SRBC). Indeed, in five on nine tests, an injection of 25 mg/kg of levamisole to female recipients either on the day of grafting or 7 days after grafting resulted in a RT50% rejection time of 25 days, compared with 46 days in untreated controls. Levamisole administered at the time of immunization with various doses of SRBC elicited earlier, higher and more sustained DTH levels than in untreated controls. Such induction of T-cell activation was accompanied by a switch on anti-SRBC antibodies from IgM to IgG. These findings confirm and extend data evidencing the ability of levamisole to recruit and activate T cells for an increased or restored cell-mediated immunity.


Immunofluorescence patterns in chronic membranoproliferative glomerulonephritis (MPGN).

90 patients, whose renal biopsies showed on light microscopy a pattern of MPGN, have been studied by immunofluorescence. 10 cases showed dense intramembranous deposits. Fluoresceinated antisera against IgG, IgA, IgM, C3, fibrinogen, IgD, IgE, C4, C1q, properdin and C3A were employed. Granular depostis of C3 were observed in all cases; IgG, IgM, properdin, C1q and C4 were found in 2/3 cases; IgA, IgE and C3A were rarely found. The localization of these deposits was parietal and often also mesangial. On the basis of glomerular deposition of C3 with or without immunoglobulins (Ig), we separated the cases into three groups: 1) C3 + Ig (59 cases), 2) predominant C3 (19 cases), 3) isolated C3 (12 cases). Most patients with dense deposits disease were classified in the third group. Deposits of C1q and C4 were found only in the first two groups. The localization of C3 deposits showed a more frequent mesangial extension in the second and third groups. Patients in these 3 groups also had different serum complement profiles. No significant differences in the major clinical features could be found in the 3 groups. Variable immunofluorescence patterns, in agreement with other serological parameters, confirm the heterogeneity of pathogenetic mechanisms in patients with MPGN.