Hatching in the sea urchin Lytechinus pictus is accompanied by a shift in histone H4 gene activity.

There is a distinct shift in histone mRNA synthesis at approximately 11--12 hr of sea urchin emhryogenesis, coincident with embryonic hatching. The synthesis of the blastula type (early) histone mRNAs gradually ceases at this stage and a new class of posthatching (late) histone mRNAs is produced. Briefly labeled early and late mRNAs were isolated and identified by means of RNA-DNA hybridization to different cloned histone genes. The late histone HI mRNA is approximately 40 nucleotides longer than the early HI mRNA. The H3, H2A, H2B, and H4 late mRNAs are 15--40 nucleotides shorter than their early counterparts. We present sequence evidence to show that the genes coding for the late H4 mRNA are a separate class from those that code for the early histone H4 message.


Simplified method for purification of ribonuclease H from calf thymus.

An improved purification procedure for the isolation of ribonuclease H(hybrid nuclease; RNA-DNA-hybrid ribonucleotidohydrolase, EC 3.1.4.34) from the thymus of 4-to 6-months-old calves yields two highly active forms of the enzyme, designated as ribonuclease H1 and H2. Their isoelectric points are 5.0 +/- 0.05 and 5.25 +/- 0.05, respectively; their molecular weight, estimated from gel filtration, is in both cases 64,000 +/- 2000. On sodium dodecyl sulfate gel electrophoresis, two principal bands were identified, with molecular weights of 32,000 and 21,000. The nature of the nucleotides at the 3'-OH terminals, produced initially by the enzymic hydrolysis of hybridized RNA, was examined and shown to be a function of the divalent metal ion employed as activator.


Absolute rates of protein synthesis during meiotic maturation of mammalian oocytes in vitro.

Measurements of the rates of incorporation of [35S]methionine into protein and the specific activities of endogenous free methionine pools have been used to calculate the absolute rates of protein synthesis in mouse oocytes during spontaneous meiotic maturation in vitro. Fluorodinitro[3H]benzene was used to determine the specific activity of the oocyte's free methionine pool. It was found that the absolute rate of protein synthesis decreased from 43 to 31 pg/hr per oocyte during meiotic progression from dictyate to metaphase II (meiotic maturation), while the size of the intracellular free methionine pool decreased from 61 to 35 fmol per oocyte during the same period. Comparable measurements made on ovulated mouse oocytes that had undergone meiotic maturation in vivo strongly suggest that the decrease in the absolute rate of protein synthesis observed during meiotic maturation in vitro is physiologically significant. An alternative method that depends upon differential expansion of the oocyte's endogenous methionine pool was also used to determine absolute rates of protein synthesis. The results of these experiments are in excellent agreement with those obtained by using fluorodinitro[3H]benzene, indicating that the oocyte's free methionine pool is not compartmentalized.


Kinetic factors and form determination of the head of bacteriophage T4.

The form of the bacteriophage T4 prehead is described by its icosahedral symmetry, its diameter, and its length. We show how each of these parameters is regulated during prehead formation and ascribe specific form-determining functions to the prehead proteins. The major protein of the head shell can assemble in several different forms. The structure produced in vivo depends on the rate of synthesis of the major protein relative to the rates of synthesis of minor shell proteins and the major core protein. From our observations, we propose a model for form determination of the prehead and suggest a pathway for the evolution of its prolate shape.


Primary organization of nucleosome core particle of chromatin: sequence of histone arrangement along DNA.

A high-resolution map for the arrangement of histones along DNA in the nucleosome core particle has been determined by a sequencing procedure based on crosslinking histones to the 5'-terminal DNA fragments produced by scission of one DNA strand at the point of crosslinking. The position of histones on DNA has been identified by measuring the length of crosslinked DNA fragments. The results demonstrate that each of the histones is arranged within several adjacent or dispersed DNA segments of a little less than 10 nucleotides in length. Histone-free intervals are located between these segments at the regular distances of about (10)n nucleotides from the 5' end of the DNA and are likely to face one side of the DNA helix. Histones appear to be arranged in a similar manner on both DNA strands and do not form "locks" around DNA. A linearized model of the core particle is proposed.


Procedure for preparation of liposomes with large internal aqueous space and high capture by reverse-phase evaporation.

Large unilamellar and oligolamellar vesicles are formed when an aqueous buffer is introduced into a mixture of phospholipid and organic solvent and the organic solvent is subsequently removed by evaporation under reduced pressure. These vesicles can be made from various lipids or mixtures of lipids and have aqueous volume to lipid ratios that are 30 times higher than sonicated preparations and 4 times higher than multilamellar vesicles. Most importantly, a substantial fraction of the aqueous phase (up to 62% at low salt concentrations) is entrapped within the vesicles, encapsulating even large macromolecular assemblies with high efficiency. Thus, this relatively simple technique has unique advantages for encapsulating valuable water-soluble materials such as drugs, proteins, nucleic acids, and other biochemical reagents. The preparation and properties of the vesicles are described in detail.


Enzymatic breakage of the cohesive end site of phage lambda DNA: terminase (ter) reaction.

An in vitro system is described for measuring the endonucleolytic conversion of the phage lambda cohesive end sites in concatemeric DNA to the cohesive chromosomal ends of the mature molecule. This enzymic process, known as the ter reaction, is catalyzed by purified lambda A gene protein. The reaction is markedly stimulated by ATP, Mg2+, spermidine, and one or more uncharacterized factors present in extracts of uninfected Escherichia coli cells. In vitro, the ter reaction proceeds in the absence of proheads under conditions that are similar to those previously found necessary for the formation of a DNA-A gene protein intermediate for the initiation of packaging.


Direct demonstration that receptor crosslinking or aggregation is important in insulin action.

Exposure of adipocytes to antibodies to the insulin receptor results in a blockade of (125)I-labeled insulin binding, stimulation of glucose oxidation, and many more insulin-like effects. Allowing for differences in purity, antireceptor antibody is equipotent with insulin on a molar basis. Both the bivalent F(ab')(2) and monovalent Fab' fragments of the antireceptor antibody are fully active in inhibiting (125)I-labeled insulin binding. Bivalent F(ab')(2) also retains its insulin-like effects. In contrast, the monovalent Fab' loses almost all ability to stimulate glucose oxidation and acts as a competitive antagonist of insulin-stimulated glucose oxidation. Addition of anti-F(ab')(2) antisera, which crosslink the Fab'-receptor complexes, results in a restoration of the insulin-like activity of the antibody. Similarly, when cells are exposed to submaximal doses of insulin, addition of anti-insulin antibodies at low concentration enhances the biological activity of insulin. These data suggest that receptor occupancy by ligand is not sufficient for signal generation and that the insulin-like effects of antireceptor antibody (and perhaps insulin itself) require receptor aggregation or clustering. This aggregation, however, appears to be independent of microfilaments or microtubules because the insulin-like effects of antireceptor antibody, and in fact, of insulin itself, are unaffected by agents that are known to disrupt these structures.


Ca2+-related regulatory function of fibrinogen.

Fibrinogen displays a regulation of considerable physiological significance by lowering the Ca2+ requirement for the conversion of the fibrin-stabilizing factor (Factor XIII) zymogen to the range of concentrations of this ion found in plasma. Fibrinogen modulates both Ca2+-dependent steps in the complex process of zymogen activation, involving the heterologous dissociation of subunits of the thrombin-modified zymogen (Factor XIII') species : formula: (see text) and the unmasking of iodoacetamide titratable sites during generation of transamidating activity : formula: (see text). It is interesting that a thrombin-independent pathway of zymogen activation : formula: (see text), which we found to operate at Ca2+ concentrations above 50 mM, is not affected by the presence of fibrinogen. Regulation by fibrinogen thus appears to be specific for controlling only the physiological pathway of zymogen conversion.


Nucleosome rearrangement in human chromatin during UV-induced DNA- reapir synthesis.

The distribution of UV-induced DNA repair synthesis within chromatin was measured in confluent human fibroblasts that were pulse-labeled with [3H]dThd (10 or 90 min) immediately after irradiation and chased in nonradioactive medium for different time periods. Initially (i.e., at the end of the pulse period), most of the repair synthesis occurs in staphylococcal nuclease-sensitive regions. With increasing chase times the nucleotides inserted during repair synthesis become progressively more nuclease resistant. Gel electrophoresis data indicate that nuclease resistance is conferred on these nucleotides by their appearance in core DNA. The kinetics of this rearrangement process are biphasic: greater than 85% of the repair synthesis sites undergo rapid rearrangement (4--5 hr); the remaining sites ( less than 15%) rearrange much more slowly, if at all. The time courses of nucleosome rearrangement and repair synthesis are similar, suggesting that nucleosome rearrangement may be induced by the repair process or that the rate of repair synthesis may be regulated by nucleosome rearrangement.


Efficient correction of a mutation by use of chemically synthesized DNA.

The mutated base in the am3 lysis-defective mutant of the bacteriophage phiX174 has been corrected by a combined in vitro enzymatic DNA synthesis and in vivo replication of the heteroduplex product. Chemically synthesized oligodeoxyribonucleotides carrying the wild-type sequence have been used to prime DNA synthesis with am3 phiX174 DNA serving as a template. The resultant semisynthetic heteroduplex composed of an am3(+) strand and a wild-type (-) strand, with one mismatched base pair at position 587 on the phiX174 DNA sequence, was used to infect spheroplasts. The progeny phage were analyzed by a parallel plaque assay on wild-type host, Escherichia coli C, to screen for wild-type phenotype, and on E. coli HF4714, an amber suppressor strain, to determine the total progeny phage. When a 23-base-long synthetic primer was used, about one-third of total progeny were found to be wild type. Shorter primers yielded lower percentages of wild type; they also had poorer priming activity.


Does irehdiamine kink DNA?

We report equilibrium, relaxation kinetic, and transient electric dichroism studies on the complex of the diamino steroid irehdiamine A with DNA. The results are consistent with a beta-kinked structure for the complex at saturation, with a kink in the DNA structure induced by a bound steroid every second base pair. The results that favor this hypothesis include an apparent length decrease of rod-like bacterial DNA molecules when only a small amount of drug is bound, followed by an apparent length increase at saturation. The limiting dichroism amplitude implies a substantial increase in the tilt of the bases relative to the orientation axis; at saturation the base UV transition moments are tilted about 31 degrees from the plane perpendicular to the orientation axis. Because of the direction of polarization of the 260-nm transition moments, the results indicate that the tilt of the bases must be predominantly in the short rather than the long axis of the base pair. The large hyperchroism of the complex is consistent with loss of base stacking, as required by a kinked structure. The kinetic results imply a bimolecular reaction mechanism, with a temperature-dependent association rate constant of roughly 10(8) M(-1) sec(-1), and a dissociation rate constant of about 5 x 10(3) sec(-1), nearly independent of temperature. The association activation energy and apparent reaction enthalpy vary from 12 to 22 kcal mol(-1); heat is absorbed on complex formation as expected for loss of base-stacking interactions. An anomalous result of the experiments is the larger apparent length increase (13%) exhibited by two eukaryotic DNAs, compared to 6% for three prokaryotic DNAs. Differences were also observed in the kinetic properties of the complexes.


Spatiotemporal pattern formation in thin layers and membranes: critical focal size.

A theory for the determination of the focal nucleation size of oscillatory membrane (or thin layer) reactions is developed on the assumption that the focal domain is square planar. From this, one can estimate that, for a period of the oscillatory mode of, say, 5 min and lateral diffusion coefficient of approximately 10(-9) cm2/sec, the critical focal area would be of the order of 148 micrometer2, corresponding to a linear dimension of approximately 12.2 micrometer2. An alternative general expression for the critical focal size, involving explicitly the viscosity of the membrane, is also given.


Isolation of methylglyoxal from liver.

Acetaldehyde and methylglyoxal were shown to be present in liver bound to protein. They were isolated in the form of 2,4-dinitrophenylhydrazones and osazones, respectively. The NMR spectrum of pure methylglyoxal was recorded.


Molecular orientation of bacteriorhodopsin within the purple membrane of Halobacterium halobium.

The direction of orientation of the protein bacteriorhodopsin within the purple membrane of Halobacterium halobium has been determined by selected-area electron diffraction of membranes preferentially oriented by adsorption to polylysine. Purple membrane is known to adsorb preferentially to polylysine by its cytoplasmic surface at neutral pH and by its extracellular surface at low pH. To maintain the adsorbed membranes in a well-ordered state in the electron microscope, an improved technique of preparing frozen specimens was developed. Large areas of frozen-hydrated specimens, devoid of bulk water, were obtainable after the specimen was passed through a Ca stearate film at an air-water interface. High-resolution microscopy was used to relate the orientation observed in the electron diffraction patterns to the orientation of the projected structure that is obtained from images. We have found that the three-dimensional structure determined by Henderson and and Unwin [Henderson, R. & Unwin, P.N.T. (1975) Nature 257, 28--32] is oriented with the cytoplasmic side uppermost--i.e., the helices fan outward on the cytoplasmic side of the membrane.


Temperature dependence of calcium-induced fusion of sonicated phosphatidylserine vesicles.

We have measured the temperature dependence calcium-induced fusion of sonicated phosphatidylserine vesicles. The vesicles were incubated in the presence of calcium at a specified temperature until the resulting aggregation or fusion process had gone to completion. EDTA was then added and the resulting final size of the vesicle population was measured by using dynamic light scattering. This final size was plotted against incubation temperature to show the temperature dependence of calcium-induced fusion. This curve has a peak near 11 degrees C which may be associated with the phase transition of the sonicated phosphatidylserine vesicles in the presence of calcium prior to the aggregation or fusion process.


Origin of the genetic code: a testable hypothesis based on tRNA structure, sequence, and kinetic proofreading.

We hypothesize that the origin of the genetic code is associated with the structure of the tRNA that existed in primal cells. The sequences of modern tRNA contain correlations which can be understood as "fossil" evidence of the secondary structure of primal tRNA. Kinetic proofreading through diffusion can amplify a low level of intrinsic selectivity of tRNA for its amino acid. Experimental tests of the theory are suggested.


Synthesis of catalase in two cell-free protein-synthesizing systems and in rat liver.

Rat liver polysomal RNA was translated in the rabbit reticulocyte lysate and in the wheat germ cell-free protein-synthesizing systems, using [(35)S]methionine as label. The catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase, EC 1.11.1.6) that was synthesized was isolated by immunoprecipitation and characterized by electrophoresis in sodium dodecyl sulfate/polyacrylamide gels followed by fluorography. The catalase made in both systems migrated more slowly during electrophoresis than did purified peroxisomal catalase. By comparison with standards of known molecular mass, the cell-free products were estimated to be about 4000 daltons larger than the purified enzyme. We also investigated the biosynthesis of catalase in vivo by injecting [(35)S]methionine into rats. The precursor of catalase known to be synthesized in liver and found in the high-speed supernatant 8 min later [Lazarow, P. B. & de Duve, C. (1973) J. Cell Biol. 59, 491-506] was isolated immunochemically. For comparison, 1-day-old completed catalase was immunoprecipitated from peroxisomes. The migrations in sodium dodecyl sulfate gels of the 8-min-old precursor and the subunit of the day-old enzyme were indistinguishable and approximately the same as the migration of the cell-free products. These results indicate that catalase's apparent size does not change when it enters peroxisomes but rather decreases during the chemical purification procedure.


Negative control of hemoglobin production in somatic cell hybrids due to heme deficiency.

In somatic cell hybrids formed by the fusion of mouse erythroleukemic cells with mouse primary bone marrow cells, retention of the X chromosome contributed by the bone marrow parent is correlated with inhibition of hemoglobin accumulation in response to dimethyl sulfoxide. The inhibition of hemoglobin accumulation is not due to the absence of globin mRNA. Dimethyl sulfoxide-treated hybrid cells accumulate polyribosomal globin mRNA to levels comparable to those of the parental erythroleukemic cells under the same conditions. Heme, or its precursor delta-aminolevulinc acid, can overcome the effects of the bone marrow X chromosome and induce hemoglobin accumulation in the dimethyl sulfoxide-treated hybrid cells. The data suggest that the X chromosome contributed by the bone marrow cells inhibits hemoglobin production by inhibiting inducible heme biosynthesis, most probably at the step catalyzed by delta-aminolevulinic acid synthetase (EC 2.3.1.37).


Units of transcription for cytoplasmic RNA in mouse myeloma cells.

The size of transcription units for several of the abundant cytoplasmic mRNA species in mouse myeloma cells has been analyzed by the ultraviolet light mapping technique. Inactivation kinetics and target size analyses for production of the predominant RNA species indicate that the mRNAs originate in precursor molecules that are 2--14 times larger than the mature mRNA. This estimate of the size of the transcription unit may be a minimum one since it would not take into account promoter-distal sequences if these were not necessary for processing of the mRNA precursor.


Magnesium reverses inhibitory effects of calcium deprivation on coordinate response of 3T3 cells to serum.

Deprivation of Ca(2+) in crowded cultures of 3T3 cells inhibits the onset of DNA synthesis. By raising [Mg(2+)] to 15 mM the inhibition produced by Ca(2+) deprivation can be fully overcome. Sparse cultures are not inhibited by a similar deprivation of Ca(2+), and therefore are not stimulated by supranormal [Mg(2+)]. The time course of stimulation of the onset of DNA synthesis by supranormal [Mg(2+)] in low [Ca(2+)] is the same as that produced by serum in physiological concentrations of Ca(2+) and Mg(2+). Concentrations of Mg(2+) > 20 mM in low [Ca(2+)] reverse the stimulation, and [Mg(2+)] >/= 30 mM kills many cells. In contrast to the stimulation by 15 mM Mg(2+), supranormal [Ca(2+)] has no effect on the onset of DNA synthesis in cultures inhibited by Mg(2+) deprivation, if the formation of insoluble Ca-P(i) complexes is prevented. Neither Na(+) nor K(+) reproduces the effects of Mg(2+). The uptake of uridine is another parameter of the coordinate response of 3T3 cells to serum stimulation that is inhibited by Ca(2+) deprivation, and supranormal [Mg(2+)] also reverses this inhibition. The results support the thesis that the coordinate response of growth and metabolism to external effectors is regulated by the availability of Mg(2+) within the cell and that the inhibitory effects of Ca(2+) deprivation are indirect and caused by a reduction in the availability of Mg(2+).


Kinetics of desynchronization and distribution of generation times in synchronized cell populations.

The kinetics of the distribution of generation times in synchronized cells can be analyzed by using Fourier transform analysis. Deviations of the experimental data from the curve of completely asynchronous growth reflect the degree of synchrony at a particular time. Fourier transform analysis of these deviations yields the average generation time as well as information on the distribution of generation times characterizing a synchronized culture. A detailed analysis of synchronized cell cultures does not provide any evidence for the existence of a subcycle or a polymodal distribution in generation times. The data do indicate that cell-cell interaction occurs at cell densities as low as 2.5 X 10(3)/cm2. It is also shown that the Eyring-Stover formalism for the dynamics of survival can correctly describe the distribution of the first round of cell divisions in a synchronized culture.


Attachment and spreading of baby hamster kidney cells to collagen substrata: effects of cold-insoluble globulin.

Studies have been carried out to determine the effects of cold-insoluble globulin (CIG) on the attachment and spreading of baby hamster kidney cells on various collagen substrata. Cell attachment to native collagen substrata occurred in the absence of CIG just as fast as attachment to dried collagen or gelatin substrata occurred in the presence of CIG. On the other hand, cell attachment to dried collagen or gelatin was markedly reduced in the absence of CIG. Cell spreading also occurred on native collagen in the absence of CIG; however, CIG was absolutely required for cell spreading to occur on dried collagen or gelatin. Finally, anti-CIG antiserum or lactoperoxidase treatment inhibited cell spreading on CIG-coated substrata but not on native collagen substrata. The data are discussed in terms of the interaction of fibroblasts with collagen in situ.


Polycationic macromolecules inhibit cilia-mediated ovum transport in the rabbit oviduct.

In both in vitro and in vivo experiments, polycationic macromolecules,such as poly(L-lysine), inhibited the transport of either surrogate or freshly ovulated cumulus masses across the oviduct epithelial surface without affecting the ciliary beat. Whereas transport across the fimbria in vivo was completely inhibited, transport down the ampulla was 3 to 7 times slower than normal. The effects of these polycations suggest that cilia-mediated ovum transport may involve the formation of transient adhesive bonds between the tip of the cilium and elements of the cumulus mass during each beat cycle of the cilium.


Inhibition of growth of transformed cells and tumors by an endogenous acceptor of galactosyltransferase.

A galactosyltransferase glycopeptide acceptor purified from human malignant effusions was tested for its effects on cell growth in vitro and in vivo. Addition of the glycopeptide to the media of cells growing in tissue culture caused a significant inhibition of attachment and growth of transformed cells but had minimal effect on nontransformed cells. Transformed hamster cells (BHKpy, BHKpygiv, NILpy) and human malignant cells (BT-20 human breast and pancreatic carcinoma cells) were killed by the addition of as little as 0.5 mug of acceptor (per ml of medium), while nontransformed counterparts did not show a significant change in growth or morphology. In vivo studies showed that the acceptor inhibited development and progression of tumors in hamsters inoculated with tumorigenic BHKpy cells. Growth of tumors was inhibited 69-94% in animals given 20 mug of acceptor subcutaneously and 39-67% when acceptor was given intraperitoneally at the time of tumor cell inoculation. Administration of the acceptor after the development of a palpable tumor ( approximately 0.5 cm) caused a 60-85% reduction in growth rate and, in some cases, actual reduction in size and disappearance of palpable tumor. These studies demonstrate that a galactosyltransferase glycopeptide acceptor purified from human malignant effusions produces selective inhibition of transformed cell growth in animal and tissue culture systems.


Amplification of DNA sequences during chicken cartilage and neural retina differentiation.

[3H]BrdUrd-substituted DNA probes were prepared from organ cultures of differentiating chicken neural retina and cell cultures of stage 24 chicken limb buds. Reassociation reactions using the neural retina probe demonstrated amplification of DNA sequences during differentiation of neural retina. This probe also contained sequences present in greater numbers in heart DNA than in DNA from undifferentiated neural retina. Reassociation reactions of both differentiated cartilage and differentiated neural retina DNA with both the neural retina probe and the cartilage probe demonstrated that at least part of the amplified sequences are tissue specific.


Amplification of the proliferative response to alloantigen by a factor present in an extract of syngeneic thymic lymphoid cells.

A synergistic interaction in the proliferative response to alloantigen has been previously noted when intact thymus cells are cultured with post-thymic (peripheral) lymphoid cells. In the present study, a factor extracted from the thymus has been shown to similarly enhance the reactivity of syngeneic lymph node cells and thus to retain the amplifier activity of intact thymus cells. The factor has no effect on lymphoid cell proliferation in the absence of alloantigen. Cells with amplifier activity are found in highest concentration in the thymus but also may be detected in spleen cells that are nonadherent to nylon wool. The factor is shown in these experiments to be derived from thymic lymphoid cells and to act primarily upon post-thymic (peripheral) lymphoid cells. As such, this factor appears to be distinct from various other thymus factors that have been localized to thymic reticuloepithelial elements and that are thought to effect predominantly the differentiation of T-cell precursors.


Amyloid fibril protein related to prealbumin in familial amyloidotic polyneuropathy.

Amyloid fibrils were concentrated from the kidney, thyroid, and peripheral nerve of six patients with familial amyloidotic polyneuropathy (FAP). The fibril concentrates were solubilized in 6 M guanidine.HCl and fractionated on Sephadex G-100 columns. The elution profile of all FAP amyloid fibril concentrates revealed a protein of apparent Mr of 14,000, designated the FAP protein, that was absent from normal human tissues treated by the same procedure and from fibrils of a primary amyloidosis liver. Antisera against whole denatured fibril concentrates prepared in rabbits reacted with the FAP protein and a component in normal human serum corresponding to prealbumin. It was further established that the FAP protein shared common antigenic determinants with human prealbumin by its reaction of identity with normal prealbumin using commercial antisera against human prealbumin. Amyloid AL or AA proteins could not be identified in FAP fibrils by sensitive immunochemical assay methods. These results suggest that the FAP protein is a unique and significant component of the FAP amyloid fibrils and that it is closely related to the 13,745 Mr prealbumin subunit.


Supplemental ascorbate in the supportive treatment of cancer: reevaluation of prolongation of survival times in terminal human cancer.

A study has been made of the survival times of 100 terminal cancer patients who were given supplemental ascorbate, usually 10 g/day, as part of their routine management and 1000 matched controls, similar patients who had received the same treatment except for the ascorbate. The two sets of patients were in part the same as those used in our earlier study [Cameron, E. & Pauling, L. (1976) Proc. Natl. Acad. Sci. USA 73, 3685-3689]. Tests confirm that the ascorbate-treated patients and the matched controls are representative subpopulations of the same population of "untreatable" patients. Survival times were measured not only from the date of "untreatability" but also from the precisely known date of first hospital attendance for the cancer that eventually reached the terminal stage. The ascorbate-treated patients were found to have a mean survival time about 300 days greater than that of the controls. Survival times greater than 1 yr after the date of untreatability were observed for 22% of the ascorbate-treated patients and for 0.4% of the controls. The mean survival time of these 22 ascorbate-treated patients is 2.4 yr after reaching the apparently terminal stage; 8 of the ascorbate-treated patients are still alive, with a mean survival time after untreatability of 3.5 yr.


Isolated microvessels: the blood-brain barrier in vitro.

Isolated bovine retinal and brain microvessels, exhibiting a patent lumen, were used to study the contribution of the microvasculature to the blood-brain and blood-retina barriers. The diffusion marker, sucrose, was taken up slowly by the isolated microvessels in contrast to leucine, tyrosine, and valine which were taken up at a considerably faster rate. Uptake of leucine was temperature dependent but resistant to inhibition by ouabain and sodium azide. The large neutral amino acids exhibited stereospecificity and cross-competition for uptake by the isolated microvessels. The apparent Kms for uptake for tyrosine, leucine, and valine were III micron,133 micron, and 500 micron, respectively.


Volatile anesthetic facilitation of in vitro desensitization of membrane-bound acetylcholine receptor from Torpedo californica.

Incubation of membrane fragments bearing acetylcholine receptors from Torpedo californica under an atmosphere of 3% halothane, 1% chloroform, or 6% diethyl ether greatly facilitates the carbamoylcholine-induced structural transition of the acetylcholine receptor reflected by alterations in the rate of binding of (125)I-labeled alpha-bungarotoxin. The half-time of this ligand-induced conformational change is decreased to 10% of the original value after incubation of the membranes with these volatile anesthetics at or near their clinical concentrations. The synergistic effects observed with the general anesthetics and carbamoylcholine are abolished if the membranes are incubated under a stream of air after exposure to the inhalational agents. The antagonist d-tubocurarine exerts a smaller yet measurable time-dependent effect on the toxin-binding properties of the membrane fragments. Treatment of membranes with general anesthetics facilitates this antagonist-induced conversion of the receptor protein as well. The synergism between ligands and general anesthetics may be due to the disruption by these inhalational agents of interactions at the protein-lipid interface, which may play a significant role in determination of receptor conformation. In addition, if the conformational change induced by carbamoylcholine observed in the snake toxin binding assay corresponds to desensitization of the receptor in vivo, facilitation of this conformational change by volatile anesthetics provides an attractive model for the pharmacological action of these compounds.


Myoinositol and phosphatidylinositol metabolism in synaptosomes from galactose-fed rats.

The effects of experimental galactose toxicity on inositol and phosphatidylinositol (PtdIns) metabolism in synaptosomes from 0- to 30-day-old rats were investigated. Galactose toxicity was induced by feeding mothers a 40% galactose diet from the 12th day of pregnancy until 19 days postpartum when the offspring were weaned onto the maternal diet. There was no decrease in myoinositol concentrations and only a small decrease in PtdIns in synaptosomes from galactose-fed rats relative to glucose-fed controls. Synaptosomes from rats on the two diets converted equivalent amounts of [U-14C]glucose to inositol and PtdIns. Acetylcholine stimulated [2-3H]inositol incorporation into PtdIns while producing a net decrease in PtdIns concentration in synaptosomes from 22- to 30-day-old rats. However, the phospholipid response to acetylcholine in synaptosomes from galactose-fed rats was impaired. Thus, the acetylcholine-stimulated labeling of PtdIns was 40--50% lower in these synaptosomes while the effect on PtdIns concentration was reduced by a maximum of 55%. The data suggest that galactose-fed rats may have either a deficiency in the number of acetylcholine receptors or a defect in some step between receptor-neurotransmitter interaction and PtdIns breakdown.


Inhibition by Z-Pro-D-Leu of development of tolerance to and physical dependence on morphine in mice.

The peptide-Z-Pro-D-Leu, injected daily in mice receiving morphine chronically, was found to prevent development of physical dependence as measured by changes in body temperature and body weight due either to abrupt or to naloxone-induced withdrawal. On the other hand, administration of Z-Pro-D-Leu only on the last day of morphine treatment did not alter the overt signs of withdrawal. Daily administration of Z-Pro-D-Leu was also effective in blocking the development of tolerance to the analgesic and the hypothermic effects of subsequent challenge doses of morphine. However, the peptide treatment did not alter the acute effects of a challenge dose of morphine on either analgesia or body temperature. No effects on memory were noted, as evaluated in a one-trial passive avoidance task. Clinical implications of the use of Z-Pro-D-Leu are discussed.


Effects of N,N-dimethyltryptamine (DMT) and 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) on shock elicited fighting in rats.

Rats were tested for shock elicited fighting under various doses of N,N-dimethyltryptamine (0.12, 0.25, 0.50, 1.0, 4.0, 8.0 mg/kg) and 5-methoxy-N,N-dimethyltryptamine (0.06, 0.12, 0.5, 2.0 mg/kg). Both drugs produced an inhibition of fighting at higher doses but no significant effects at lower doses. The effects of these drugs on shock elicited fighting, as well as on other behaviors, thus differ from those of another indole hallucinogen, d-lysergic acid diethylamide, and are discussed in relation to their effects on single unit activity of the raphe-serotonin system and their interaction with other neurotransmitter systems.


Uncoupling of electrotonic synapses by calcium.

The degree of axo-axonal synaptic coupling between nerve cells in the buccal ganglion of Navanax was investigated in relation to intracellular ionic calcium. Increasing intracellular Ca2+ by injection of Ca2+, injection of Na+, or application of ionophore X537A produced uncoupling after at least 90 min, if metabolic inhibitor was present in the medium. Subsequent removal of the metabolic inhibitor reestablished the coupling in less than 30 min. Injected Sr2+ also mimicked the uncoupling action of Ca2+. The presence of a metabolic inhibitor alone had no effect on the coupling. These results lead to the following conclusions: (i) Uncoupling is due to an increased free Ca2+ concentration at the junctions. (ii) The liberation of endogenous sequestered Ca2+ is not sufficient to produce uncoupling except if an excess Ca2+ had been previously sequestered. The electrical synapses in the buccal ganglion of Navanax thus appear to be affected by Ca2+ in a similar way as gap junctions studied in non-neural tissues.


[Aseptic necrosis of the femoral head in lymphogranulomatosis and chronic myeloic leukemia treated intermittently with cytostatic agents and steroids (author's transl)].

Four male patients with the age from 31--43 years with lymphogranulomatosis and a 23 year old patient with chronic myeloic leukemia developed aseptic necrosis of the femoral head 15 to 69 months after treatment with a combination of cytostatic substances and steroids. In a patient who received maximal prednisone applications aseptic necrosis of the humeral head has been observed also. With increasing life expectancy asceptic bone necrosis due to treatment can appear as a late complication. The early recognition is important. The advancing of this irreversible bone destruction and the associated morbidity can be avoided by immediate cessation of the steroid application. Conservative treatment is indicated.


Two-dimensional echocardiographic identification of a right ventricle tumor.

A metastatic tumor in the right ventricle was clearly visualized using two-dimensional echocardiography. The location, size, and mobility of the tumor were easily demonstrated. Two-dimensional echocardiography is superior to M-mode echocardiography in such cases.


Radiation-induced soft-tissue and bone sarcoma.

From the records of Memorial Hospital of the past 50 years, 47 cases with an established diagnosis of radiation-induced sarcoma were identified and divided into two groups: the first included 20 cases of soft-tissue sarcoma arising from irradiated tissues, and the second comprised 27 cases of bone sarcoma arising from normal bones in the irradiated field. Medians for the latent periods from irradiation to diagnosis of bone and soft-tissue sarcoma were 11 and 12, years, respectively. In bone sarcomas, the latent period was longer after larger radiation doses and children appeared to be more susceptible to cancer induction than adults. Criteria for establishing the diagnosis of radiation-induced sarcoma and the magnitude of the risk of bone sarcoma are discussed.


[Therapeutic principles in angioma of the mandible: applications in relation to a clinical observation (author's transl)].

When confronted with a case of angioma of the mandible, treatment should be directed towards two main areas:--to stop blood loss. Ligature of the external carotid can be life-saving, but it does not prevent the formation of nearby anastomotic vessels which refill, more or less rapidly, the external carotid axis. Ligature make embolization impossible by femoral way. A by-pass operation to improve permeability is also dangerous if not impossible. Ligature should be reserved only for those cases in which there is an immediate threat to life. On the contrary, embolization is necessary before surgery. --to treat the angioma. As radiotherapy is not effective or is dangerous, surgical treatment is necessary; either by a conservative operation or by radical resection. All these facts are illustrated dramatically by the case reported.


[Aneurysmal cysts located in the maxilla or mandible (author's transl)].

Aneurysmal cysts of the mandible and maxilla are rare conditions, though not exceptional, which are seen in particular in the child and adolescent. A part from facial asymmetry and tumefaction, it is rare to find other clinical manifestations. No neurological signs were seen in the present study. An aneurysmal cyst gives a radiological appearance of non-characteristic lysis compatible with a large range of diagnoses. Histological study permits early diagnosis but must always involve the whole specimen with careful examination to detect any other associated lesion. The pathogenesis of the condition remains obscure and, at the extreme, it may be questioned whether the aneurysmal cyst is a separate entity or a particular form of chronic osteopathy.


[Salivary imprints on the mandible. The sign of lordosis of the ramus (author's transl)].

All of the principal salivary glands are in contact with the membranous mandible, in the form of contiguous relationships which develop and disappear respectively at the time of phylogenesis and ontogenesis of the first branchial arch. A contrast must also be drawn concerning the static relations between the submaxillary and sublingual glands and the inner aspect of the horizontal branch and the dynamic relations between the posterior edge of the ramus and the parotid gland ensured by the inter-mandibulo-parotid sliding space. In this perspective, the physiological slope of the posterior border of the ramus is certainly of parotid origin. This slope may be exaggerated in the presence of a parotid tumour, forming the indirect radiological sign of sagittal lordosis of the ramus, sometimes associated with a certain degree of frontal scoliosis in the case of a tumour with pharyngeal prolongation. Once again in this perspective, the inter-mandibulo-parotid sliding space makes for easy separation of the anterior parotid aponeurosis of the mandible and of its muscular sling.


[LLL plasty in reparative surgery of the face (author's transl)].

The problem of the repair of loss of cutaneous substance from the face is extensively studied in works on plastic surgery. The so-called LLL lozenge plasty of Dufourmentet no longer has the place of which it is worthy, when it is not ignored altogether. The authors here stress the advantages: simplicity, minimal separation of the skin from underlying structures, ease of application using local anaesthetic, minimal scarring, aesthetic quality. The limitations of this autoplasty are also described, in particular with regard to the extent of the repair and the problem of malignancy.


[Xeroderma pigmentosum. Therapeutic indications on the basis of 3 cases seen recently (author's transl)].

This condition is a genodermatosis, seen chiefly around the shores of the Mediterranean, characterised by early pigment disturbances which progress virtually inexorably towards a diffuse epitheliomatosis which usually results in death before the age of 20 years. Progression of the lesions is precipitated by exposure to UV rays. These lesions are seen essentially in exposed areas, in particular oculopalpebral. Treatment is first preventive (decrease in exposure to sun and protection). Otherwise, surgery remains the most effective method: either excision as required, or extensive cervicofacial prophylactic excision followed by grafting.


Morphologic changes in the rat enamel organ following a single intraperitoneal injection of sodium fluoride.

Enamel organs in developing teeth of young rats were studied after single intraperitoneal injections of a high dose of sodium fluoride (60 mg NaF/kg body wt.). The study employed primarily light microscopy, but electron microscopy was used to clarify some of the light microscopic findings. The pathogenesis of the fluoride-induced changes was followed during 72 h. Cellular changes were consistently found in the molars, but were never seen in the incisors. In the maxillary molars, ameloblastic injury was most commonly seen on the mesial surfaces of the cusps. One hour after injection, the most prominent findings were swollen mitochondria in the secretory ameloblasts and cleft formations between the ameloblasts and the enamel matrix. The clefts were filled with a stippled material. Some of the clefts gradually expanded to cystic cavities. The stippled material began to calcify after 24 h and formed small, darkly stained globules. After 72 h dearranged ameloblasts were found as islands intermingled with calcified rounded structures in the stellate reticulum. In stratum intermedium numerous atypic autophagic vacuoles appeared 2 h after injection. No light microscopic changes were observed in the postsecretory ameloblasts.


Effect of dextranase on plaque formation and caries development in the rat.

Plaque formation and caries development were studied in 0-M rats fed Diet 2000 and infected with S. mutans 6715 and fecal flora from older caries-active rats. Merck dextranase, Beckman dextranase or Beckman glucanase 447 were administered singly or in combination to groups of 12 rats either as an addition to the diet or as a "mouthwash" twice daily, 5 per week. All enzymes studied were associated with significant inhibition of both plaque formation and caries development, especially on the buccal and lingual surfaces.


Effect of experimental neutropenia on oral wound healing in guinea pigs.

The influence of experimental neutropenia on the wound healing process in standardized excisional palatal wounds was studied in 16 guinea pigs. Corresponding wounds in 15 normal animals were used as controls. Neutropenia was induced and maintained by daily injections of heterologous anti-neutrophil serum. One-micron sections from biopsies of palatal mucosa sampled 6, 24, 48 and 120 h after wounding were evaluated with special reference to the progress of epithelial wound repair and to the occurrence and location of inflammatory cells and bacteria. In animals treated with anti-serum, neutrophilic leukocytes disappeared from the wound cavity, whereas other inflammatory cells remained unchanged. Further bacterial invasion deep into the cavity was observed. The epithelial repair took place at a deeper level in the wounds of neutropenic animals compared with those of normal animals. The rate of re-epithelialization was the same in neutropenic and control wounds. The experiment indicates that the neutrophils in oral wounds provide a principal agency for host defense against microorganisms and probably thereby indirectly determine the direction and level of epithelial cell migration.


Relation of amylase to starch and Lycasin metabolism in human dental plaque in vitro.

Acid production activity (APA) in plaque suspensions from glucose, boiled soluble starch and hydrogenated starch hydrolysate (Lycasin) was studied in 11 subjects. Amylase (alpha-1,4-glucan 4-glucanohydrolase, EC 3.2.1.1) activity was measured in plaque and whole saliva samples from the same persons. Lycasin was found to be hydrolyzed by salivary amylase under the formation of di- and oligosaccharides, however, with a lower rate than starch. A high correlation was found between APA from glucose and from soluble starch and between APA from soluble starch and plaque amylase activity. No correlation was found between amylase activity in saliva and APA from soluble starch or between amylase activity in saliva or plaque and APA from Lycasin. APA from Lycasin was about 62% and from soluble starch about 76% of the APA from glucose. 0-25% of the total number of cultivable microorganisms from the plaque produced extracellular starch-degrading enzymes. No correlation was found between number of starch-degrading microorganisms and APA from soluble starch or between these numbers and the plaque amylase activity. By electrophoreses only amylase fractions of human origin were found in whole saliva, plaque supernatants and plaque suspensions, indicating that the microbial amylase activity in the plaque is low compared with that of salivary origin.


An in vitro study with various vehicles of diffusion of formocresol and its components.

Pulpotomy in primary teeth using the formocresol method results in varying degrees of devitalization of the root pulp. The extent of this devitalization depends on, among other things, the ability of the components of formocresol to leave the dressing. The purpose of this study was to evaluate the rate and duration of diffusion of the components of formocresol when incorporated in different vehicles. The antimicrobial effect of the drugs was used to assess the diffusion of the components of formocresol in blood agar, with a sensitive microorganism as an indicator. Evaluation of the MICs assessed in broth medium for formalin, formocresol and cresol, respectively, and the zone size of growth inhibition on blood agar from these components when incorporated in ZnO or ZnO-eugenol cement, suggested that the initial zone of inhibition from formocresol was due mainly to the diffusion of formaldehyde. Cresol diffused more slowly from the dressing. The presence of eugenol in the dressing, as in ZnO-eugenol cement, gave smaller initial release of formaldehyde, formocresol and cresol compared with the release from ZnO, but more prolonged diffusion. A higher initial release of formaldehyde was obtained when the formocresol was incorporated in ZnO alone compared with ZnO-eugenol cement or Pharmatec.


Pulp condition of successfully formocresol-treated primary molars.

The aim of the study was to assess the state of the pulp of primary teeth successfully treated by formocresol pulpotomy. Nineteen teeth, all of them with clinically and radiographically successful treatments, were extracted 3-24 months after treatment. The pulpal condition had changed in all the teeth. Inflammatory reaction or necrosis was observed in all teeth. Dentinal resorption followed by apposition of hard tissue were common findings. In the teeth with vital tissue only in the apical area, the tissue had minor or no signs of inflammation. Microorganisms could be demonstrated in the necrotic tissue in one tooth. The wide range of pulpal conditions observed indicated that there was no typical tissue reaction to formocresol even though treatment was clinically successful. The present study confirms that the formocresol method should be regarded only as a means to keep primary teeth with pulp exposures functioning for a limited period of time.


A 2-year follow-up of primary molars, pulpotomized with a gentle technique and capped with calcium hydroxide.

The prognosis for pulpotomy of primary molars with calcium hydroxide as wound dressing was evaluated clinically and radiographically. Thirty-three primary mandibular molars were amputated under the following conditions: (1) chronic coronal pulpitis, (2) the amputation was done with diamond instruments and a high-speed machine under aseptic conditions, and (3) application of calcium hydroxide in contact with the wound surface. After 1 year the treatment was regarded as successful for 22 of the teeth (67%); 11 teeth showed internal dentin resorption. After 2 years the frequency of success, allowing for drop-out, was 59%. Internal dentin resorption was seen in 14 root canals; in 10 of them within the first 6 months. A histologic study of nine root pulps with internal dentin resorption revealed an extra-pulpal blood clot on the wound surface in five.


Mercury vapor levels in a dental laboratory.

Mercury vapor levels associated with grinding amalgam models and mulling amalgams in the palm of the hand following trituration have been measured in a dental laboratory in inhalation position. The threshold limit value of airborne mercury of 0.05 mg/m3 was essentially exceeded in the grinding procedure of amalgam. Levels in excess of seven times this value were recorded. During mulling the mercury vapor level fluctuated around the threshold limit value. The mean mercury concentrations did not essentially exceed the threshold limit value.


Effect of chlorhexidine-coated dressings on plaque formation after gingivectomy.

The aim of this clinical study was to evaluate the effect on plaque formation after gingivectomy when the periodontal dressing Coe-Pak was coated with chlorhexidine-hydrochloride powder. The study indicates that no additional plaque-inhibiting effect can be obtained by this method.


A critique of animal models in antibiotic research.

The interactions between microbes and antimicrobial agents in vitro are often markedly different from those in vivo, presumably because of pharmacological factors and host defenses. Although animal models have long been used to evaluate the efficacy of chemotherapeutic agents, there are few guidelines for the conduct of these studies. Therefore, the results of these investigations must be assessed critically in terms of the balance between the infectious challenge and the therapeutic response, and in terms of their relevance to human disease. It has been clearly demonstrated that the "freshness" of the infecting organism, the interval between infection and therapy, the order of administration of drug combinations, and the presence of foreign bodies, may have a crucial impact upon the outcome of animal trials. Less well studied have been the influence of the quantity and growth phase of the infecting inoculum, the use of single- as opposed to multiple-dose therapy, and the anatomical and pharmacological attributes of the particular animal species. Greater understanding of these factors would resolve some of the apparently contradictory results of various investigations, and would permit more rational design of these studies in the future.


The tissue cage model in the distribution of antibacterial agents.

Developments in the measurement of interstitial tissue fluid using the tissue cage model are described. The design and physical characteristics of tissue cages are examined and evidence is presented to show that the fluid contained within these cages is representative of interstitial tissue fluid. The distribution of a variety of antibacterial agents into tissue cage fluid is examined and shows that this technique is a reliable experimental model for the study of drug distribution. The results also show that some antibacterial agents may never, normally, distribute into the tissue fluid and that the use of tissue homogenates, especially the kidney, is unreliable as a guide to the tissue concentration of a drug.


Tissue cage experiments with beta-lactam antibiotics in rabbits.

An animal model in which antibiotic concentrations can be meausred in intersittial fluid (IF) withdrawn from subcutaneous tissue cages has been used. Although the physiological significance of IF is not well established, this model allowed the comparison of 1) two pharmacological forms of the same drug (bacampicillin and ampicillin were compared after a single oral dose; and 2) drugs of the same group in a single i.m. injection study and in a cumulative effect study. These data provide new criteria for clinical choice of antibiotics. A rapid penetration into IF can be explained by a low degree of serum protein binding, but a highly bound drug is not restricted to the intravascular space. In this animal model we have also shown that an 0.25 h i.v. infusion of cephalothin induced higher IF levels than an i.v. bolus injection and an 1 h i.v. infusion. Using a single i.v. bolus injection of various cephalosporins, we have shown that a two open compartment model cannot explain both serum and IF data. Sustained late IF levels suggested the hypothesis of a deep compartment.


Experimental models for determination of antimicrobials in prostatic tissue, interstitial fluid and secretion.

Two new animal models were used to evaluate the usefulness of several antimicrobials for the treatment of bacterial prostatitis. An experimental bacterial prostatis was created in dogs and the concentraion of six antimicrobials (erythromycin, rosamicin, trimethoprim, sulphamethoxazole, ampicillin and doxycycline) measured in plasma and prostatic secretion and their concentration ratios compared to previous studies in healthy dogs. Prostatic interstitial fluid concentrations of the three basic drugs (erythromycin, rosamicin, trimethoprim) were determined from samples obtained from implanted tissue chambers. At the same time samples of plasma, prostatic secretion and urine were collected and their concentration ratios compared. Drug levels in prostatic secretion of dogs with infected prostatic glands were different from those without inflammation, but the same mechanism of drug diffusion into the prostatic secretion seems to be active during infection. Prostatic interstitial fluid concentrations of the three basic drugs were always lower than the simultaneous prostatic secretion levels. These findings may have clinical application in the treatment of bacterial prostatitis.


Factors influencing the penetration of antimicrobial agents into the cerebrospinal fluid of experimental animals.

Successful therapy of bacterial meningitis is dependent upon achieving adequate antibacterial activity in the CSF. The percent penetration (CSF concentration/serum concentration X 100) of various antimicrobial agents was determined in a rabbit model of bacterial meningitis. The percent penetration of the penicillin and cephalosporin derivatives was found to vary inversely with the protein binding of the respective drugs. Esterification of ampicillin increased its lipid solubility and likewise increased the penetration into the CSF. Probenecid competitively inhibits the active transport efflux of various organic acids from the CSF and increased the CSF concentrations of penicillin and cephalosporin derivatives. The percent penetration of all drugs was increased in the presence of the inflamed meninges.


Antibiotics in bone tissues. Methodological and practical aspects.

With regard to determination of antibiotic levels in bone, variance in results may be obtained as a consequence of type of the bones involved, degree of penetration of the drug used and of assay method performed. Measurements of antibacterial activity in bone from patients undergoing orthopaedic surgery were performed after preoperative treatment with doxycycline, lincomycin, clindamycin or cefuroxime. In performing the assay by the agar diffusion method, after extraction of the bone specimens in buffer according to classical systems, the concentrations of doxycyline were in the range of 0.05--0.6 microgram/g, clindamycin 0.4--4.9 microgram/g, lincomycin 1.7--2.9 microgram/g and of cefuroxine about 0.4 microgram/g. After electrophoresis in agarose-gel and followed by microbiological assay higher levels of these drugs were estimated possibly as a consequence of a diminution in the binding capacity of bone.


A review of models for the therapy of experimental infections.

The advent of several new antibiotics able to counter drug-resistant bacteria, the problems in carrying out well-controlled clinical trials and the occasional disparity between in vitro and in vivo activity of antimicrobials compel us to resort to experiments using animal models in order to evaluate different therapeutic regimens. We wish here to discuss the prerequisites of a reliable animal model for the therapy of experimental infections and to analyze the influence of combined antimicrobial therapy on the outcome of non-human infections. The interaction between antibiotics and infected tissues will also be considered. Finally, we shall examine the interrelations between host defenses and antibiotics in models for experimental infections.


Evaluation of amino penicillins in experimental infections in mice.

The therapeutic activity of bacampicillin compared to that of ampicillin and amoxycillin was evaluated against experimental infections in mice. Median curative doses (CD50) were determined in groups of animals challenged with bacterial suspensions injected intraperitoneally together with mucin and treated orally with the penicillins. When treated directly after the infection bacampicillin was slightly more active than ampicillin, whereas it was significantly more active than ampicillin and at least as active as amoxycillin when the treatment was instituted not until four hours after infection. Bacterial counts made on various organ homogenates from infected animals four hours after the infection showed that a generalized infection with high bacterial concentrations had developed. Penicillin administration caused a significant reduction in the bacterial counts and the bactericidal activity in vivo obtained after administration of bacampicillin appeared as good as that of amoxycillin.


Comparison of antibiotic assays using different experimental models and their possible clinical significance.

Different experimental models were applied to study the pharmacokinetics of antibiotics in "interstitial fluid" ("i.f.") in rabbits. Two types of tissue cages were used and the results from these experiments were compared with those obtained analysing the antibiotic concentration in the mucous membrane of the oral bucca and maxillary sinus in rabbits. A similar determination was done in the mucous membrane of sinus in man. The concentration of antibiotics in the "i.f." from steel-net chambers in rabbits closely follows that of the mucous membranes of the maxillary sinus in man and the oral bucca in rabbits. Experimental bacterial infections of the tissue cages resulted in decreased amounts of biologically active antibiotics in the "i.f." for some antibiotics compared to that of the uninfected cages. An increase of the concentration of antibiotics in the infected cages was noted simultaneously with a decrease in the number of viable bacteria during the healing process. The clinical significance of the models will be discussed.


Absorption of bacampicillin and ampicillin and penetration into body fluids (skin blister fluid, saliva, tears) in healthy volunteers.

Equimolar doses of bacampicillin, which is rapidly converted to ampicillin in the body by hydrolysis, and ampicillin were administered orally, in the case of ampicillin also by intravenous injection, to 10 healthy subjects (cross-over study). Comparison of the areas under the serum concentrations curves after intravenous and oral administration showed that bacampillin was absorbed to 95% and orally given ampicillin to 35%. The mean peak serum levels (Cmax) after 0.8 g of oral bacampicillin were higher (15.9 microgram/ml) and appeared earlier (tmax 60 min) than after 0.556 g of oral ampicillin (3.2 microgram/ml, tmax 150 min). One and three hours after oral administration skin blister fluid contained four times more ampicillin after doses of bacampicillin than after oral ampicillin. One hour after intravenous injection of ampicillin the skin blister concentrations were 20 times higher than after oral administration of this antibiotic and three to four times higher than after oral administration of bacampicillin. The levels in saliva and tears were also determined and showed similar relationships. Since higher peaks serum levels resulted in higher and longer lasting concentrations in the extravascular space, bacampicillin is to be preferred for oral therapy.


Transfer of penicillin G and ampicillin into human skin blisters induced by suction.

The antibiotic concentrations in untreated and endotoxin-treated suction blisters was studied in 15 healthy adults. In a pilot study, 2 mega units of penicillin G were given as an intravenous bolus injection to two subjects. For further studies, a single dose of 800 mg bacampicillin was given orally to 13 individuals. The penicillin G concentrations in the blister fluid were highest approximately 15 minutes after the dose, and exceeded that of serum after 1.5 hours. With ampicillin the blister fluid concentration reached maximum levels after approximately 2 hours, were equal to serum levels after 3 hours, and were later persistently in excess of serum levels. The ampicillin half-life was 136 and 100 minutes in the two types of blister fluid, as compared to 65 minutes for serum. A marked differences between the antibiotic concentrations in inflammatory and non-inflammatory blisters was seen in the pilot study with penicillin G. However, in the experiments with bacampicillin, no significant difference was demonstrated. This suction blister technique appears to be a useful method for studies on extravascular antimicrobial activity in man.


Changes in protein binding during disease.

Disease states can alter protein binding of antimicrobials by either a reduction in the concentration of serum proteins or the accumulation of endogenous compounds, such as bilirubin and free fatty acids (FFA), that affect drug-protein interactions. In terms of protein concentration, extremely low levels of albumin (less than 2.5 m/100 ml) are required to markedly reduce binding of antimicrobials. In vitro addition of high concentrations of bilirubin and FFA to normal serum reduces binding of most antimicrobials. However, binding of some antibiotics appears to be enhanced at lower concentrations of FFA probably by an allosteric mechanism. These in vitro observations have been confirmed in sera from patients during heparin administration and patients with hyperbilirubinemia. Reduced protein binding of acidic antimicrobials in uremia appears to be associated with the accumulation of another, as yet unknown, endogenous binding inhibitor. Significant reduction in protein binding can affect the distribution of drugs and results of microbiologic assays.


Significance of the pharmacokinetics of antimicrobial drugs.

Administration of an active drug to the intact human body leads to a "drug-body" interaction: the drug exerts its effect on the body, the body disposes of the drug. Administration of an antimicrobial drug to a human body infected with pathogenic bacteria leads to a "drug-bacteria" interaction in addition to "drug-body" and "bacteria-body" interactions. Of these complex interacting mechanisms only the disposition effect of the human body on antibacterial drugs and the effect of antimicrobial agents on bacteria have been quantified, analyzed, and are thus predictable. Postulates have been derived from the findings of these studies and have given the rationale for proper antimicrobial therapy under clinical conditions: antimicrobial actions are functions of the duration and concentration of the active antimicrobial principle at the physiological site of action. Optimal therapeutic efforts consider the need for individual treatment with respect to the choice and type of dosage regimen of the antimicrobial agent administered.


Clinical significance of tissue penetration of antibiotics in the respiratory tract.

Concentrations of antibiotics in bronchial secretion vary widely and cannot be easily related to physico-chemical characteristics. Serum and sputum concentrations do broadly correlate in the case of penicillins, some cephalosporins and some tetracyclines. Antibiotic concentrations in bronchial secretion (although not necessarily in lung tissue) are always much lower than in serum, with a ratio of about 20% for tetracycline, 3--4% for ampicillin, 4--50% for gentamicin and tobramycin. Concentrations will often be adequate to inhibit highly sensitive pathogens but marginal or ineffective for those less sensitive, e.g. carbenicillin or gentamicin for Ps. aeruginosa.


Pharmacokinetic study of beta-lactam antibiotics in bronchial secretions.

The objective of the study was to evaluate the concentrations obtained in serum and bronchial secretions after administration of five beta-lactam antibiotics: cephradin (1 g per os) and cefoxitin (2 g i.v. infusion), amoxycillin (1.0 g per os), bacampicillin (0.4 g and 0.8 g per os) and ampicillin (1.0 g per os). 123 adult patients were included in the study and received a single dose of the tested drug. Serum and mucus samples were collected simultaneously 30 minutes, 1, 2 or 4 hours after administration of the drugs. Mucus samples were taken by fibroscopy but in some patients the samples were collected through a tracheostomy cannula which allowed sampling at different time intervals. The results show that the concentrations of penicillins in bronchial secretions increase progressively between one and four hours after administration of the drugs. Bronchial levels obtained after oral administration of ampicillin are low, not more than 5 to 10% of serum levels. The other antibiotics tested show worthwhile concentrations in bronchial secretions, especially with cephalosporins and bacampicillin which exhibits higher serum and bronchial concentrations than ampicillin.


Concentrations of ampicillin in pleural fluid and serum after single and repetitive doses of bacampicillin.

In patients with pleural effusions due to malignant disease, estimations of ampicillin were made on simultaneously obtained samples of blood and pleural fluid: (1) from patients (n=11) after the administration of a single dose of 400 mg of bacampicillin, and (2) from patients undergoing treatment with 800 mg of bacampicillin twice daily (a) during the 12 hours after the first dose (n=10) and (b) during the 7 hours after the third dose (n=9). Bacampicillin gave concentrations in the pleural fluid well above the MIC of common pathogens including H. influenzae. Mean peak levels were 1.2 microgram/ml after the 400 mg dose and 3.8 microgram/ml after the first and third doses of 800 mg. The peak appeared later in the pleural fluid in comparison with serum peak levels. The elimination half life was considerably longer in the pleural fluid.


Methods for the clinical evaluation of antibiotics in urinary tract infections.

Antibiotic treatment of urinary tract infections is less than completely successful. Factors involved in the outcome are complex and include host, bacterial and drug factors. Eradication of the bacterial strain from the urine after the discontinuation of drug administration is a critical index in the clinical evaluation. Categorical reports of in vitro bacterial susceptibility correlate poorly with clinical results. Achievement of a bacterial inhibitory concentration of drug in the urine is essential for cure and probably more important than the plasma concentration. The conditions associated with cure and failure in 368 episodes of infection were examined. Distribution of the patients into groups designated "anatomical normal", "systemic nephropathy" and "uronephropathy" showed each of these host factors to have a significant primary effect. In the latter two, but not in the former, the drug susceptibility of the infecting bacterial strain and whether or not it was E. coli or another species of gram-negative bacillus were additional significant factors. When antibiotic treatment was assessed in host comparable episodes a significant rank order of the effectiveness of drugs could be made according to their class action. Bactericidal inhibitors of protein synthesis were best; drugs used primarily as urinary antiseptics were the least effective.


Tissue penetration of antibiotics; an overview.

The recent development of several techniques has made it possible to more adequately study the tissue penetration of various antibiotics. The major technical advances making this possible have been various assay systems permitting measurement of antibiotics in very small amounts of fluid or tissue. In addition, various tissue cages and the use of skin blisters has been a popular means for testing antibiotic penetration into extra-cellular fluid.


Kinetics of tissue penetration. Are high plasma peak concentrations or sustained levels preferable for effective antibiotic therapy?

The experimental evidence and the theory of antibiotic transport into peripheral foci of infection have been discussed. Support is presented in favour of the concept that intermittent dosage with peak concentrations of sufficient size would seem preferable. The duration of plasma concentrations above certain thresholds is a basic requirement for successful antimicrobial therapy.


The penetration of antibiotics into bacterial cells: significance to antimicrobial action.

The penetration of antibiotics into the microbial cell is reviewed from the standpoint of the structure and function of the several types of membranes which constitute permeability barriers to the passage of hydrophilic molecules. It is clear that little is actually known about the mechanisms by which the majority of antibiotics gain access to their site of action within the target cell. Sufficient evidece is at hand to indicate that resistance to several groups of antibiotics is determined by changes in the permeability of the cell membranes, the genes for which are often carried on R-plasmids. The importance of studies to determine the precise mechanisms by which each type of antibiotic permeates the membrane of the bacterial cell is stressed by a discussion of several approaches to enhancing antibiotic permeation through manipulation of either the drug or the target cell based on knowledge of the uptake mechanisms.


Theory and practical impact of binding of antimicrobials to serum proteins and tissue.

Binding of antimicrobials to serum proteins and tissue affects their distribution, elimination and antimicrobial activity. Penetration of drugs into most tissues and interstitial and inflammatory fluids correlates with level of free drug in serum. Serum protein binding can increase or decrease the rate of drug elimination depending on whether total or free drug is available to the excretory or metabolic routes of elimination. Binding to soluble intracellular proteins (ligandin and fatty acid binding protein) appears to be important in the cellular transport and elimination of antimicrobials by renal tubular secretion and hepatic extraction. Although only free, unbound drug is antimicrobially active, the lack of well designed studies has prevented precise quantitation of the influence of binding on therapeutic efficacy in vivo. Pharmacokinetic considerations predict that serum binding greater than 80% would be necessary to significantly reduce free levels of drug in the body. However, extensive protein binding is often compensated for by greater intrinsic activity of lipophilic antimicrobials.


[Principles of reasonable oral rehabilitation].

Dentistry today is becoming an amalgamation of medical science and precision technology. However, not all the techniques introduced in past years can be qualified as progress when the clinical results are closely examined. These results show that it is necessary to constantly reevaluate one's work in order to maintain a high standard of treatment. Every dental intervention should be planned in concurrence with the principles of prevention and cure, and executed with care and precision to avoid any progress or recurrence of the existing disease. Every oral rehabilitation should be effected following a strict sequence--establishment of good oral hygiene, precise diagnosis of the disease and careful study of the case, planning and coordination of the various interventions necessary, elimination of diseased tissue and restoration of the dentition in such a manner as to retain as much healthy tooth substance as possible and to avoid any over energetic--iatrogenic--elimination of tissue.


[Case analysis and planning: functional aspects].

Great emphasis is posed on the fact, that for all cases of reconstructive dentistry some basic information is required prior to any preparation of teeth. This basic information consists of study models, vitality and periodontal pocket probings, of full mouth X-rays and an intraoral analysis. If more information in regard to the solving of a case is necessary, diagnostic occlusal adjustment by the use of semi-adjustable articulators, eventually a diagnostic wax-up or set-up is required. Treatment planning is the first step to successful restorative dentistry. This gives the possibility to predict the prognosis of reconstructive cases prior to the treatment phase.


[The role of orthodontic surgery in mouth rehabilitation].

The surgical treatment of malformations of jaws offers actually many possibilities. Basic principles of this specialized surgery are exposed: an exact diagnosis, the problem of incisions which must be hidden, age upon operation and association with other specialties. In the oral rehabilitation, this type of surgery permits total correction of complex malformations, which are impossible to treat completely by other methods.


[Practical methods for the transfer of models to the articulator].

There is no standard method for transferring models to an articulator, which applies to all needs of practice. The best way, adapted to existing occlusal circumstance, to the planned prosthetic rehabilitation and to the technical possibilities must be planned in each case.


Increased excretion of urinary glycosaminoglycans in a case of Rothmund Thomson syndrome.

The exercretion of urinary total glycosaminoglycans (GAG) in a case of Rothmund Thomson syndrome associated with osteosarcoma was increased about 2--3 times that of normal control. Since the excretion of urinary total GAG in two cases of osteosarcoma was within normal range, the increased excretion of total GAG might be on account of the metabolic disorder of GAG in Rothmund Thomson syndrome. The prominent fractions obtained by Dowex 1 column chromatography from this syndrome were 0.75 M Fr and 1.0 M Fr, in which the major GAG were indicated to be partially degraded forms of heparan sulfate and chondroitin sulfate, respectively.


[The arterial blood supply of the human mandible].

The arteries of 22 mandibles injected with Kallocryl M were examined. The first group consisted of mandibles with the full complement of teeth. At the inner side, there were numerous anastomoses between the submental artery, the sublingual artery, the ascending palatine artery and the mylohyoid ramus. Furthermore, the dental rami branched into the periost. At the outside, the mental artery as well as the submental and inferior labial arteries contributed to the arterial supply. In the second group of mandibles (with intact incisors), these war a marked reduction of the anastomoses of the inferior alveolar artery in the middle region. The third group of mandibles (which were edentulous) showed anastomoses of the submental and sublingual arteries in the region of the incisors. The outside was supplied by the submental and inferior labial arteries. The mental artery exislar artery was demonstrated in 4 cases. The reduction of anastomoses concerned the inferior alveolar artery.


[The stress situation in ambulatory oral surgical interventions].

On the basis of results from various studies, the authors show that the psychic initial condition and the psychophysical stress during the operation are of paramount importance to the rise of complications.


[Problems in the treatment of fronto-basal fractures].

Midfacial fractures are frequently combined with frontobasal fractures. For this reason, it is important to the oral surgeon to be knowlegeable of the basic principles of the treatment of frontobasal fractures. The rule of general surgery that any open injury should be transformed into a closed one, also applies to these fractures. The indication for operation and the time of operation depend upon the kind of lesion. The intradural closure of the dural is regarded as the method of choice. Details of the operating technique are presented.


[Fluoride metabolism in the rat. 3. Distribution in the gastrointestinal tract after oral application].

With relation to the investigation of the mechanism of absorption in the gastrointestinal tract, the present third communication deals with a study of the distribution or absorption of fluorine-18 after oral application. This mode of application creates experimental conditions simulating the conditions of water fluoridation. Special attention is paid to the fluorine distribution or absorption in the following six portions: stomach, segments 1--3 of the small intestine, coecum und rectum. Furthermore, the question of its possible accumulation in the soft parts and its retention in the hard tissues were examined as compared with the results from intravenous application.


[The number of salivary corpuscles in healthy subjects and in patients with periodontal disease].

Using a standardized, well reproducible method, the authors determined the number of salivary corpuscles in 174 healthy subjects (1,400 to 2,000/microliter) and 109 patients with periodontal disease (5,300 to 7,800/microliter). The statistical analysis revealed a highly significant difference between the two groups. There was a positive correlation between the number of salivary corpuscles and periodontal disease indices.


[Stomatological health education for children and adolescents].

Principles of dental health education is childhood and adolescence are outlined with special regard to priorities related to the age-specific state of dentition development. The paper concluded with organizational advice deduced from practical experience.


[Alteration of leukocyte AMP- and IMP-pyrophosphorylase stability in leukemia].

Effect of thermic treatment and of pre-incubation with phosphoribosyl pyrophosphate on activity of AMP- and IMP-pyrophosphorylases were studied in leukocytes under chronic forms of limpho- and myeloleukoses. AMP-pyrophosphorylase from leukemia leukocytes was inactivated after heating up to 65 degrees, which, at the same time, as distinct from the enzyme of normal leukocytes, proved to be reversibly reduced after incubation of the heated cell extracts with phosphoribosyl pyrophosphate. IMP-pyrophosphorylase of leukocytes was activated at this temperature; the activation of the enzyme was 15--20% higher in leukemic leukocytes than in leukocytes of healthy donors. The data obtained demonstrate the increased thermostability of purine nucleotide pyrophosphorylase from leukemic leukocytes, which is apparently due to conformational peculiarities of the enzyme molecules.


Childhood leukemia: perspectives 1978.

With intensive chemotherapy and a minimum of hospitalization, great progress has been made in extending the lives of children with acute lymphoblastic leukemia. Of equal importance is attentive support for those whose lives are lengthened and their families.


Advantages and dangers of artificial ventilation.

In modern anesthesiology artificial ventilation has many advantages, especially when compared to manual ventilation, nonetheless the "educated hand" of the anesthesiologist. However many dangers and pitfalls exist during controlled ventilation. A survey of them is given. In more detail are discussed: hyperventilation, hypoventilation, accidental deconnection of the tubings, accidental hyperpression, failure of the cycling mechanism, faults in fresh gas administration. A plea is made for immediate observation of the patient and respiratory dynamics when connecting a respirator.


Therapeutics of caries prevention--concepts and prospects.

Despite intensive research, water fluoridation and, where practiced, diet control, remain the most effective methods of preventing caries. In this paper, a number of approaches discussed appear to hold promise that they may enhance the caries preventive effect of fluoride, and others, when developed and applied, may hasten the day when dental caries will cease to be a public health problem.


Traumatized primary anterior teeth. Prognosis related to calcific reactions in the pulp cavity.

The frequency of a complicating pulp necrosis and the process of the physiologic root resorption were studied in traumatized primary teeth exhibiting partial or total pulp obliteration. The material comprised 88 incisors in 72 children aged 0.7--5.7 years (mean 2.9 years) at the time of injury. Trauma had resulted either in subluxation (25 teeth), or luxation (13 teeth), whereas the type of injury was unknown in 50 teeth. All cases were observed until eruption of the permanent incisors. Forty-four teeth initially displayed a reversible greyish color. The ultimate finding observed in all teeth was, however, varying degrees of yellow discoloration. Periapical pathologic findings indicative of pulp necrosis were observed in 9 teeth, from 1.6--4 years (mean 3 years) after the time of injury. Extraction was performed immediately, and none of the successional teeth showed developmental disturbances. The process of root resorption was classified as normal in all primary teeth. Subsequent eruption of the permanent successors occurred without any registered complications.


Surface adsorption of fluoride and ionic exchange reactions on hydroxyapatite.

The experiments showed that a part of the fluoride which was taken up by hydroxyapatite or teeth at low concentrations of fluoride at neutral pH was soluble in alkali (IN KOH, 24 h) and was thus not fluoroapatite. Calcium fluoride could not form under the present conditions because the solubility of this compound was not exceeded. It is suggested that the alkali soluble fluoride is adsorbed to calcium ions bound as counterions in the hydration layer of the hydroxyapatite or the enamel. This is consistent with previous findings in this laboratory, showing that fluoride displaced acidic proteins adsorbed to calcium receptors on the hydroxyapatite surface in the same way as other anions displace proteins. It could also be shown that polyanions and polycations adsorbed to hydroxyapatite surfaces by ionic exchange, displacing phosphate or phosphate and calcium respectively in the process. A model is suggested which differs slightly from that proposed by Bernardi.


Choice of dental care among 16--18 year olds in Oslo.

One of the objectives of organized school dental service is to create ability and willingness among young adults to maintain a preventive oral health care, e.g. regular dental visits. In order to investigate the decisions about and plans for dental care among school dental service leavers a questionnaire was sent to a probability sample of 258 young adults who had finished ninth grade eight months earlier. The participation rate of the Youth Dental Program (YDP) was approximately 90%. The drop-outs were made up of at least two rather distinct groups. One of them was dominated by subjects with a high social background and they chose to a great extent care in private practice. The other group was dominated by young men with a low social background. They finished school early and expressed pessimistic expectations to the life-time of their own teeth.


Peridontal status following surgical-orthodontic alignment of impacted teeth.

Treatment of impacted teeth is often a combination between oral surgery and orthodontics. This study evaluates the gingival condition of impacted teeth after surgical-orthodontic treatment, where two different surgical methods were used. In one group (n = 11) the teeth were radically exposed and orthodontically moved to their final position. In the other group (n = 11) the teeth were partially exposed by raising a mucoperiosteal flap. Orthodontic traction was then applied; whereafter the flap was sutured back into place. The results showed that one of the teeth in the partial exposure group and seven in the radical exposure group showed loss of attachment. This study indicates that a combination of mucoperiosteal flap technique and applied orthodontic traction is prefered to minimize the loss of attachment in cases of displaced impacted teeth.


Explanatory model for the interaction of factors in the caries process.

The interaction of factors in the caries process has recently been discussed in a number of articles. Based on this, a new explanatory model has been constructed, consisting of an equilateral triangle with one of the apices on a horizontal line, along which dietary and oral hygiene habits are scaled. The triangle represents the total area of interaction. A horizontal line of resistance cuts off a lower part corresponding to the area within which caries does not occur. Through planogeometric calculations the remaining part of the triangle can be divided into areas, approximately corresponding to the relative caries values of various combinations of dietary and oral hygiene habits. The model has proved to be a useful instrument for demonstrating and creating an understanding of interactive processes among various groups of dental health personnel. The example presented is based on a pilot study of 55 4-year-old children in Malmö.


Serum iron level in acute lymphoblastic leukaemia.

Serum iron level (SIL) was studied by atomicabs orption spectrophotometry in 57 children with acute lymphoblastic leukaemia. SIL depended on the activity of the disease. Mean SIL was highest in untreated children. Normalization of myelograms during treatment was accompanied by a decrease of SIL. A significant decrease was observed in organ localizations and in infections during remission of the leukaemia. SIL may be helpful as an auxiliary test in the management of leukaemic children.


Simultaneous occurrence of non-Hodgkin's lymphoma and spontaneous acute granulocytic leukemia.

The diagnosis of non-Hodgkin's lymphoma with spontaneous acute granulocytic leukemia was confirmed by examination of the patient's bone marrow and peripheral blood specimens at the light and electron microscopic level, and by autopsy findings. Only one previous case of simultaneous non-Hodgkin's lymphoma and acute myelomonocytic leukemia with no prior history of chemotherapy, radiotherapy, or both, has been reported. Although the present patient was given no mutagenic therapy, his chronic exposure to an unknown insecticide may have played a leukemogenic role.


Equilibrium theory revisited: factors influencing position of the teeth.

The major primary factors in the dental equilibrium appear to be resting pressures of tongue and lips, and forces created within the periodontal membrane, analogous to the forces of eruption. Forces from occlusion probably also play a role in the vertical position of teeth by affecting eruption. Respiratory needs influence head, jaw and tongue posture and thereby alter the equilibrium. "Deviate swallowing" is more likely to be an adaptation than a cause of tooth changes. Patients with failure of eruption have been recognized and alterations in the eruption mechanism may be more important clinically than has been recognized previously.


Pre-eruptive movements of the mandibular third molar.

1. It would appear that the developing mandibular third molar is continually changing its angular position relative to the mandibular plane and adjacent teeth. 2. For normal uprighting and eruption to occur growth at the mesial root must dominate. 3. In the absence of sufficient space, uprighting movements of the mandibular third molar may result in mesioangular impaction. 4. Vertical and distoangular impactions can be explained by continued growth at the mesial root while the crown is prevented, at its distal surface, from erupting. 5. If growth at the distal root becomes more influential, severe mesioangular or horizontal impaction may occur.


Orthodontic effects of loop design and heat treatment.

The effects of heat treatment on Blue Elgiloy wire and loops formed from this wire were determined. The optimum heat treatment temperature was established to be in a narrow range in the vicinity of 950 degrees F. This regimen increases the yield and ultimate strengths of this wire. Heat treatment also produced a modification of the load-deflection characteristics of the loop configuration tested. Overall, heat treatment of the wire is indicated by this study.


Small airways dysfunction in influenza A virus infection: therapeutic role and potential mode of action of amantadine.

Previous studies have demonstrated alterations in gas exchange and pulmonary mechanics in presumed and documented viral upper respiratory infections. In our laboratory, using sensitive and noninvasive testing, we have demonstrated significant and prolonged alterations of pulmonary mechanics in uncomplicated natural influenza A infection, which implicate increased resistance in small airways as the cause of dysfunction. Amantadine administration in established influenza A infection has been associated with an accelerated improvement of clinical illness and pulmonary physiologic dysfunction. Preliminary study suggests that this is due to neither cholinergic blockade nor bronchodilation.


Methisazone therapy in pediatric vaccinia complications.

Methisazone 40 mg/kg/day was administered orally to six pediatric and one adult patient who contracted vesicular complications affecting the skin or mucocutaneous junctions 3 to 9 days after antismallpox vaccination, and to one elderly man with myeloid leukemia who developed vaccinia necrosum. Therapy was commenced 2 to 10 days after onset of complications and was administered for 3 days. All patients with skin or mucocutaneous complications showed dramatic clinical responses within one day after commencement of antiviral chemotherapy, and complete recovery occurred within one week. Clinical improvement was noted 4 days after therapy was begun in the case of vaccinia necrosum, and recovery occurred after 3 weeks.


Animal corneas as tools for the testing of antiviral compounds.

As a number of viruses can be titrated on corneas of various animals, the corneal method was used to detect antiviral activity of some derivatives of thiazolidine and related compounds with a low toxicity. In herpetic infections of rabbit cornea, 2-(1-isopropylidene)azino-3-(beta-D-ribofuranosyl)-methoxycarbonylmethylenethiazolidine-4-one showed for a mean of 2.1 greater activity than IDU. In piglet corneas, lesions produced by adenovirus type 8 were inhibited by a mean of 3.4 log CID50 by 5-(2,3,5-tribenzoyl-beta-D-ribofuranosyl)-(2H)-tetrazol and by a mean value of 3 log CID50 by 4-(2,3,5-tri-o-benzoyl-beta-D-ribofuranosyl) thiosemicarbazide. The multiple microinoculation technique of calculating corneal infectivity allows many of the advantages of sensitivity and statistical validity usually associated only with cell culture methods to be obtained from an in vivo system. Furthermore it allows observations concerning toxicity of the drug tested on the eye. We believe that this method should form a part of the "biography" of any compound seriously considered for the ocular treatment of virus diseases. This test goes a long way in bridging the gap between in vitro tests and trials in humans.


The relative potencies of anti-influenza compounds.

The relative potencies of some standard anti-influenza compounds have been examined in vitro by plaque reduction in calf kidney cells, and in vivo by reduction in virus titers of the lungs of infected mice. Strains belonging to the four subtypes H0N1, H1N1, H2N2, and H3N2 were employed to compare the activity of amantadine hydrochloride and ribavirin. In vitro for all strains except A/NWS/OO(H0N1) amantadine hydrochloride was 3-4 times more active than ribavirin. In vivo with sensitive strains amantadine hydrochloride produced a plateau effect at higher dose levels, but at lower dose levels was marginally more active than ribavirin. The sensitivity of A/Hong Kong/1/68 (H3N2) to amantadine hydrochloride, rimantadine hydrochloride, cyclooctylamine, and ribavirin was also investigated. In vitro rimantadine hydrochloride was similar in activity to amantadine hydrochloride and ribavirin, but cyclooctylamine was considerably less active. In vivo cyclooctylamine was active only at 150 mg/kg/day, whereas rimantadine hydrochloride produced a plateau effect over a range of concentrations from 9,12-150 mg/kg/day.


Synergistic effects of antiviral agents and humoral antibodies in experimental Herpesvirus hominis encephalitis.

Experimental Herpesvirus hominis encephalitis in 3-week-old Swiss mice was utilized to evaluate the antiviral effects of adenine arabinoside (ara-A), phosphonacetic acid (PAA), and humoral antibodies to H. hominis (HIG). Administration of ara-A, PAA, or HIG during the early phase of infection reduced the mortality rate of H. hominis encephalitis in mice. Combined administration of humoral antibodies with an antiviral agent (ara-A or PAA) resulted in an enhanced protection, accompanied by a decreased virus concentration in the brain tissues and a diminished tissue injury. The generality of this enhancing effect of humoral antibodies on the action of antiviral agents and its possible use in therapy of viral infections warrant further investigation.


Antiviral action and selectivity of 6-azauridine.

6-Azauridine (AzUrd) is a broad-spectrum antimetabolite that inhibits both DNA and RNA virus multiplication. Prior work indicated that several AzUrd-sensitive viruses induced an increase in the level of uridine kinase, and this might explain the selective activity of AzUrd on such viruses. Present studies compared AzUrd sensitive and resistant viruses with respect to their orotic acid pathways by labeling cells with [14C]-orotic acid during the latent period of viral infection. No differences were detected by this method with either vaccinia, Newcastle disease, or vesicular stomatitis viruses. AzUrd inhibits transport of orotic acid into the cell by 30%, while incorporation of orotic acid into cellular RNA is inhibited by 50% (taking into consideration the 30% already noted) when the highest concentration of antimetabolite is used. This suggests that, in addition to blocking orotidylic acid decarboxylase, AzUrd may act on some other site (sites) of action in the inhibition of virus multiplication.


Antiviral activities of 4'-(9-acridinylamino)-methanesulfon-M-aniside (SN11841).

SN11841 [4'-(9-acridinylamino)-methanesulfon-m-aniside] is an antitumor compound discovered by B.F. Cain. The LD50 for BALB/c mice with single intraperitoneal dosage is approximately 25 mg/kg. RLV-(Rauscher leukemia virus)-induced splenomegaly, a disease indicator in BALB/c mice, is inhibited at SN11841 doses not causing acute mortality. The life span of RLV-infected mice increases at some SN11841 doses. SN11841 does not have direct, or virolytic effects on RLV under conditions approximating those of antiviral effectiveness. SN11841 is cytotoxic for cells in tissue culture, as measured by inhibition of growth rate or vital dye uptake. At nontoxic concentrations SN11841 has no effect on RLV infectivity for murine cells, as determined by XC-cell induced syncytium formation. SN11841 has antiviral activity against vaccinia virus in tissue culture but is inactive against herpes simplex (Type 1), vesicular stomatitis, encephalomyocarditis, or reoviruses. SN11841 apparently does not act by inducing interferon. SN11841 is chemically labile, particularly in the presence of sulfhydryl compounds, but the degradation products resulting from prolonged storage in media are neither cytotoxic nor antiviral.