Local and systemic antibody response to oral administration of glucosyltransferase antigen complex

The salivary and serum immune responses to orally administered glucosyltransferase antigen complex from Streptococcus mutants strain 6715 were investigated in hamsters. All enzyme-linked immunosorbent assay was used to measure the antibody quantity and isotype, and a [14C]glucosyl-labeled sucrose incorporation assay was used to measure functional inhibition of the enzyme. A total of 21 to 27 daily doses of antigen administered in hamster oral cavities elicited salivary immunoglobulin C and immunoglobulin A antibody responses and functional inhibitory activity. The salivary response increased throughout the immunization procedure, and the amount of salivary antibody was dependent upon the dose of antigen given. The salivary response to a second oral administration of antigen for 4 days showed some features of anamnesis. The response after a second antigen administration was detected sooner than the primary response, and somewhat higher levels of antibody and inhibitory activity were observed. Serum antibody (immunoglobulin G and immunoglobulin M) and functional inhibitory responses were also elicited by oral administration of the soluble enzyme antigen. These responses were lower than responses induced by local injections of antigen in complete Freund adjuvant. The ability to evoke a salivary immune response to the glucosyltransferase antigen complex may increase the potential of using this antigen in an effective caries vaccine.

A modified tongue-lip adhesion for Pierre Robin anomalad

A modified tongue-lip adhesion for Pierre Robin anomalad, based on the work of Douglas (1946), Routledge (1960) and Randall (1977) is described. Modifications include placement of the incision and stripping of the geniglossus muscles from the mandible. Conservative non-operative management is successful for most patients, but an adequate surgical adhesion avoids tracheostomy when more active treatment is needed.

Prolongation of canine pancreas allograft survival with cyclosporin A: preliminary report

Studies were conducted on dogs to test the efficacy of cyclosporin A (CyA) in prolonging normoglycaemia and graft survival after whole-organ pancreas allograft transplantation. Five dogs subjected to pancreatectomy alone served as controls. Withholding immunosuppression after transplantation (five animals) resulted in the same median duration of survival as occurred in the controls (13 days). Azathioprine and steroids (seven animals) produced median durations of normoglycaemia and survival of 9 and 23 days respectively. Animals given CyA 18 mg/kg/day (five) and 25 mg/kg/day (10), however, showed median durations of normoglycaemia of 18 and 55 days (p less than 0.05 and p less than 0.02) respectively and median survival times of 36 and 85 days (NS and p less than 0.02). If CyA proved effective in controlling rejection of pancreas allografts in man it would offer unstable diabetics in renal failure a more hopeful outlook than conventional immunosuppression.

The reaction of choline acetyltransferase with sulfhydryl reagents. Methoxycarbonyl-CoA disulfide as an active site-directed reagent

The reaction of choline acetyltransferase with methoxycarbonyl alkyl disulfides leads to a progressive loss in enzyme activity as the size of the alkyl group increases from methyl to n-butyl. Reaction with 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) or methoxycarbonyl coenzyme A (CoA) disulfide, leads to a total loss of enzyme activity. DTNB inactivation is biphasic (k1 = approximately 9 x 10(2) M-1 s-1, k2 = approximately 6 x 10(1) M-1 s-1) with the slow phase being diminished by acetyl-CoA. Methoxycarbonyl-CoA disulfide inactivation is also biphasic (k1 = approximately 2.1 x 10(3) M-1 s-1, k2 = approximately 6 x 10(1) M-1 s-1), with the rapid phase being diminished in the presence of acetyl-CoA. Inactivation by methoxycarbonyl methyl disulfide, ethyl disulfide, or hydroxyethyl disulfide, or by methyl methanethiosulfonate is not biphasic. Pretreatment of the enzyme with methyl methanethiosulfonate, which leads to a 25% loss in enzyme activity, abolishes the fast phase of DTNB inactivation, the slow phase of methoxycarbonyl-CoA disulfide inactivation, and any further inactivation by methoxycarbonyl ethyl disulfide. These results are interpreted to suggest that choline acetyltransferase contains two classes of reactive sulfhydryl groups, neither of which are required for enzyme activity.

Effect of oral administration of glucosyltransferase antigens on experimental dental caries

The effect of oral administration of soluble antigen preparations containing glucosyltransferase on dental caries in hamsters was studied. Immunization was accomplished by feeding glucosyltransferase for 21 to 27 consecutive days. This immunization regimen resulted in the formation of salivary antibody, which was detected by functional inhibition of enzymatic activity and by a modified enzyme-linked immunosorbent assay. A serum response also occurred in two of the three experiments performed. After infection with cariogenic Streptococcus mutans strain 6715, glucosyltransferase-fed hamsters had significantly fewer S. mutans cells recoverable from molar surfaces on six of nine occasions, compared with buffer-fed control groups. Hamsters orally immunized with glucosyltransferase also always had lower mean caries scores and mean numbers of lesions than comparably infected sham-immunized groups. The results of this study suggest that significant protection from experimental dental caries can be accomplished by oral administration of soluble antigen preparations containing glucosyltransferase.

The neonatally thymectomized rat: a model for compensatory IgM antibody formation in exocrine secretions

The effect of T-cell deprivation on IgM antibodies in saliva was studied in rats. IgM was never detected in salivas obtained from normal or sham-thymectomized rats, but was detected in saliva samples from 8/15 (53.3%) rats that had undergone neonatal thymectomy. All (6/6) neonatally thymectomized rats exhibited an IgM antibody response to DNP in salivary secretions after local immunization with a T-dependent antigen (DNPBGG), while no IgA anti-DNP activity was detected in saliva from these antimals. IgM antibodies were detected in saliva from 5/7 thymectomized rats following local injection with a T-independent antigen (DNP-Lys-Gicoll). This was accompanied by detectable but substantially reduced levels of secretory IgA antibody in saliva from 7/7 rats. The results suggested that absent or decreased salivary IgA responses accompanying T-cell deprivation in the rats are compensated for by secretion of IgM antibodies into the saliva. The neonatally thymectomized rat may thus provide a model for the study of synthesis, secretion and protective potential of exocrine IgM antibodies.

Accumulation and excretion of [1-14C]bis(tri-n-butyltin) oxide in mice

Laboratory COBS strain albino mice were administered [1-14C]bis(tri-n-butyltin) oxide in dilute aqueous solutions. Test solutions were prepared by using an elastomeric controlled-release formulations that emitted the agent at a constant rate. Tissue and excreta were periodically analyzed for 14C by standard liquid scintillation counting methods. Assuming that the label was not cleaved from the tin, 90--96% of the ingested agent was excreted, predominantly in the feces. Of the remainder, kidney levels were high, possibly indicating metabolism; tissue accumulation was diffuse, with liver, spleen, and fat predominating. Blood levels were low. Termination of organotin ingestion led to rapid clearance of storage sites.

Organization and development of brain stem auditory nuclei of the chicken: dendritic gradients in nucleus laminaris

Nucleus laminaris (NL) is a third-order auditory nucleus in the avian brain stem which receives spatially-segregated binaural inputs from the second-order magnocellular nuclei. The organization of dendritic structure in NL was examined in Golgi-impregnated brains from hatchling chickens. Quantitative analyses of dendritic size and number were made from camera lucida drawings of 135 neurons sampled from throughout the nucleus. The most significant results of this study may be summarized as follows: (1) The preponderant neuron in n. laminaris may be characterized as having a cylindrical-to-ovoid cell body, about 20 micrometer in diameter. The neurons comprising NL were found to be nearly completely homogeneous in issuing their dendrites in a bipolar fashion: one group of dendrites is clustered on the dorsal surface of the cells, the other group on the ventral. The dendrites of NL are contained within the glia-free neuropil surrounding the nucleus. From the rostromedial to the caudolateral poles of NL there is a gradient of increasing extension of the dendrites, increasing number of tertiary and higher-order dendrites, and increasing distance from the somata of the occurrence of branching. (2) The total dendritic size (sum of the dorsal) and ventral dendritic lengths of the cells) increases 3-fold from the rostromedial to the caudolateral poles of NL. About 50% of the variance in dendritic size is accounted for by the position of the cells in NL, and the gradient of dendritic size increase has the same orientation across NL as the tonotopic gradient of decreasing characteristic frequency in NL. (3) From the rostromedial pole to the caudolateral pole of NL there is an 11-fold decrease in the number of primary dendrites along a gradient coinciding with the length and frequency gradients. Sixty-six percent of the variance in dendrite number is accounted for by position in the nucleus. (4) The correlation of dorsal and ventral dendritic size on a cell-by-cell basis is not high (r = 0.47), indicating a fair amount of variability on the single-cell level. On the other hand, the average dorsal dendritic length within an isofrequency band in NL correlates very highly with the average ventral dendritic length. Thus, on an areal basis, the amount of dendritic surface area offered to the dorsal and ventral afferents is tightly regulated. (5) The dorsal and ventral dendrites have separate gradients of increasing length and number across NL. The dorsal gradients are skewed toward the rostrocaudal axis, while the ventral dendritic gradients are skewed mediolaterally. (6) There was no correlation between either dendritic size or number of primary dendrites and the size of the somata in NL, which remains relatively constant throughout the nucleus. Several hypotheses about the ontogenetic control of dendritic structure are examined in light of the above data. Of these, the hypotheses that the ontogeny of dendritic size and number is largely under afferent control receives a great deal of circumstantial support.

Reverse phase high pressure liquid chromatographic determination of some iodoamino acid contaminants in sodium liothyronine or sodium levothyroxine

Some iodoamino acids have been separated and determined by high pressure liquid chromatography on octadecylsilane reverse phase packing with a mobile phase consisting of methanol, potassium phosphate monobasic, and orthophosphoric acid at 44 degrees C. The method separates and quantitates mixtures of 3,5-diiodothyronine, liothyronine, isoliothyronine, and levothyroxine. The procedure provides an accurate, sensitive, and rapid estimation of decomposition and/or impurities in standards in approximately 30 min, at the less than 75 pmole level, using an ultraviolet detector at 254 nm.

Observer bias and error in the integumentary clinical diagnosis of chronic anaemia

In 74 patients believed to have chronic anaemia, 1 541 individual clinical assessments of haemoglobin levels were made from various sites. By comparison with laboratory values, there were statistically significant differences in the majority. In most instances these were not clinically important. The conjunctivae, the oral mucosa and the tongue were the integumentary sites that seemed to give the most accurate clinical assessment, while the appearance of nail-bed, palmar creases and facies did not correlate with laboratory findings. Bias appeared to be a factor in clinical estimates. There was no evidence that experience made clinicians more accurate.

Cardiovascular effects of benzquinamide

The cardiovascular effects of benzquinamide were evaluated in anesthetized dogs. Intravenous benzquinamide, 0.5 to 5 mg/kg, caused tachycardia, elevated blood norepinephrine levels, frequent ventricular arrhythmias, and brief hypotension. Ganglionic blockade by hexamethonium prior to administration of benzquinamide prevented the tachycardia and alterations in norepinephrine levels but prolonged the period of hypotension. In isolated mesenteric arterial preparations benzquinamide interfered with contractile force generated by potassium chloride, norepinephrine, and prostaglandin F2 alpha. It is concluded that benzquinamide directly relaxes vascular smooth muscle thereby producing in vivo reduced peripheral vascular resistance and hypotension, which are compensated for by reflex sympathetic activation.

The effect of neonatal thymectomy on the level of salivary and serum immunoglobulins in rats

The effect of neonatal thymectomy on the level of salivary and serum immunoglobulins was studied in conventional rats. Salivary SIgA levels were significantly decreased from weaning (day 20) through the termination of the experiment, while salivary IgG levels were generally unaffected by neonatal thymectomy. Serum IgA was detected at a later interval after birth in samples from thymectomized rats than from normal and sham-thymectomized rats and the levels of serum IgA in the thymectomized rats remained 4-5 times lower throughout the 115 day experimental period. Serum IgG was decreased by approximately 40% from days 28 through 115 after birth in the thymectomized animals, while serum IgM was apparently unaffected by the neonatal thymectomy. These findings indicate that the synthesis of salivary SIgA is markedly influenced by the presence of thymus-derived cells and it is suggested that these cells may control and/or modify immune responses in oral secretions.

Preparation of glucosyltransferase from Streptococcus mutans by elution from water-insoluble polysaccharide with a dissociating solvent

Glucosyltransferase (EC 2.4.1.5) was obtained by dissociation from water-insoluble polysaccharide in the presence of 6 M guanidine-hydrochloride. Water-insoluble polysaccharide was synthesized by cell-free culture supernatants from Streptococcus mutans strain 6715. Gel filtration of the glucosyltransferase on a column of 8% agarose in phosphate buffer, followed by filtration on a column of 4% cross-linked agarose in 6 M guanidine-hydrochloride, gave a 23-fold enrichment of the enzyme. The enriched glucosyltransferase preparation contained 22% carbohydrate and eluted at a position corresponding to a molecular weight of 422,000. Polyacrylamide gel (5%) electrophoresis of this preparation revealed two regions which stained for protein, formed water-insoluble polysaccharide in the presence of sucrose, and precipitated with antisera directed to crude glucosyltransferase preparations. The guanidine-eluted enzyme could be primed by 5 X 10(-5) M dextran T10 (molecular weight, 10,000). High-molecular-weight glucan and a possible glucan-binding protein were also obtained after the final gel filtration step (4% cross-linked agarose) in addition to glucosyltransferase.

Divalent cations and angiotensin-stimulated sodium transport

The presence of calcium in the fluid in which intestinal or kidney tissue is incubated is required for the tissue to respond to angiotensin. Everted sacs of rat colonic mucosa exhibited an increased rate of fluid transport in the presence of angiotensin; this response was lost when the serosal fluid, but not the mucosal fluid, was calcium-free. Angiotensin-stimulated transport was maintained when calcium was replaced with strontium or barium, but was lost when calcium was exchanged for magnesium. Similarly, calcium ions were required in the incubation fluid of rat kidney cortex slices to demonstrate angiotensin-enhanced sodium transport. These observations are discussed in relation to the possible roles of divalent cations in the mechanism of action of angiotensin.

Effects of local immunization with glucosyltransferase fractions from Streptococcus mutans on dental caries in hamsters caused by homologous and heterologous serotypes of Streptococcus mutans

Seven serotypes of Streptococcus mutans have been identified. The biochemical, genetic, and serological characteristics of these serotypes have indicated that certain serotypes are quite similar, whereas others are quite distinct. The effect of local immunization with glucosyltransferase (GTF) enzymes from serotypes a, c, or g on infection and disease caused by homologous or heterologous cariogenic S. mutans is reported. Organisms with either similar (a and g) or different (c and g) biochemical and serological characteristics were selected for heterologous challenge. NIH white hamsters were injected four times at weekly intervals with GTF prepared by 6 M guanidine-hydrochloride elution from water-insoluble glucan of serotypes a, c, or g, which resulted in enzyme (homologous) inhibitory activity in sera and salivas. After infection of GTF-immunized and sham-immunized groups of hamsters with cariogenic S. mutans of the same serotype as the injected antigen (homologous infection) or with S. mutans of a different serotype from the injected antigen (heterologous infection), the numbers of streptomycin-labeled S. mutans, caries, and lesions were determined. Immunization with GTF preparations from each of the three serotypes resulted in statistically significant reductions in the extent of infection and disease and number of lesions caused by infections with homologous cariogenic S. mutans. Statistically significant reductions in these three parameters were also observed in groups immunized with enzyme from serotype a (strain E49) and challenged with cariogenic serotype g (strain 6715) organisms; or immunized with enzyme from serotype c (strain Ingbritt) and challenged with cariogenic serotype g (strain 6715) organisms; or immunized with enzyme from serotype g (strain 6715) and challenged with cariogenic serotype c (strain Ingbritt) organisms. These studies suggest that soluble antigen preparations containing GTF from one serotype may elicit a protective immune response against infection with cariogenic S. mutans from many or possibly all serotypes.

Direct connections between mitochondria and catecholamine-storage vesicles demonstrated by high voltage electron microscopy in rat adrenal medulla

Tubular channels from mitochondria to catecholamine-storage vesicles have been demonstrated in thick sections of adrenal medullary tissue from hypoglycemia-stressed rats by the use of the high voltage electron microscope. The function of these connections is not presently known although they may serve as channels for the transport of materials such as high-energy nucleotides from one organelle to the other. The present study has examined only the adrenal medulla, but it should be considered that such connections may also exist in other neural cells and possibly other cells in which there is intracellular transport of ATP.

High-voltage electron microscopy of adrenal medulla: direct connections between mitochondria and catecholamine-storage vesicles

A high-voltage electron microscopic study of adrenal medullary cells from hypoglycemia-stressed rats revealed the existence of tubular channels which create a luminal continuity between the mitochondrial compartment and the catecholamine-storage vesicles. It is suggested that these channels allow for the transfer of materials such as high-energy nucleotides between the mitochondria and the catecholamine-storage vesicles without an intervening membrane.

Isolation and properties of a succinylated subunit of human thyroglobulin

A subunit of succinylated (40:1 molar ratio, succinic anhydride:lysine residues) human thyroglobulin (Tg) was prepared by gel filtration on 6% and 4% agarose. This subunit (S-8) had a sdegrees20, w of 7.6S, Ddegrees20, w of 2.96 x 10(7) and an equilibrium molecular weight of 165,000 after correction for bound succinic anhydride (SA). The S-8 component was suggested to be a quarter unit of intact Tg. The S-8 and intact Tg had nearly identical amino acid compositions with differences only in glutamic acid, glycine and proline. The iodine content of both components was similar. The succinylated S-8 subunit, as well as material which sedimented with a value of 2S or less, retained some but not all heteroantigenic and autoantigenic sites in immunodiffusion and inhibition of passive hemagglutination.

Isolation and properties of thyroglobulin-related 4S protein in the soluble fraction of thyroid tissue

A 4S protein which is thyroglobulin-related and which is immunologically distinguished from unusually iodinated albumin-like proteins or impaired substances of thyroglobulin synthesis, was found in the thyroid-soluble fraction even in the normal gland, though in minute amounts. In the present study, purification and characterization of the substance has been carried out using human and hog thyroid glands. This protein contains some of the immunospecific determinants of thyroglobulin, although the amino acid composition of the protein differs from that of thyroglobulin. The 4S protein has a molecular weight of about 58,500 as determined by the sedimentation equilibrium method. Interestingly, the present 4S protein is eluted just in front of, or together with, thyroglobulin by gradient elution chromatography on a DEAE-cellulose column, and it is precipitated with thyroglobulin at 1.9 M ammonium sulfate. Therefore, it was concluded that a molecular-sieving process is necessary for the purification of thyroglobulin, in addition to a complex procedure which consists of ammonium sulfate fractionation and DEAE-cellulose chromatography.

Cross-protective aspects of glucosyltransferase antigens in the hamster caries model

1) Glucosyltransferase serotypes a and g are closely related antigenically but are more distantly related to GTF of serotype c, based on assays of inhibition of total glucan synthesis. 2) Local immunization with GTF from serotype c S. mutans reduces the colonization, caries, and lesions caused by infection with the homologous strain compared with sham injected controls. 3) Local immunization with GTF of serotype c S. mutans reduces the colonization, caries, and lesions caused by infection with S. mutans of serotype g (strain 6715).

Synchronous VBM and radiotherapy in the treatment of squamous cell carcinoma of the head and neck

Since April 1974, 60 patients with squamous cell carcinoma of the head and neck region, of poor prognosis and generally in advanced stages, were treated with the combination of a cytotoxic regimen--VBM (Vincristine, Bleomycin and Methotrexate) and radical radiotherapy. The essential feature of the combination is the administration of pulses of VBM synchronous with a course of fractionated external radiotherapy in order to achieve potentiation of radiotherapy. On average 4-5 pulses of VBM were given during treatment, combined with radiotherapy on a Cobalt unit. The selection, preparation and management of the patients are described. Intense mucositis and intercurrent infection provide the main problems during treatment and close management is essential. Late complications have not been a serious problem. The crude actuarial survival rate at 24 months is 61%. The probability of survival without any recurrence to 24 months following initial treatment is 46%. Local control was achieved by the initial treatment in 43 patients. These results suggest that potentiation of radiotherapy and an increased therapeutic ratio has been obtained by the addition of VBM to radiotherapy and there is a possibility that the occurrence of distant metastases has been reduced or postponed.

Subunit structure of 27 S thyroid iodoprotein

The dissociation of thyroid 27 S iodoprotein by sodium dodecyl sulfate (SDS) and by succinic anhydride was investigated by means of ultracentrifugation and polyacrylamide gel electrophoresis. The iodoprotein obtained from either a human or hog was dissociated into three kinds of subunits (S-19, S-17 and S-12) by SDS treatment. At increased concentrations of SDS, the S-12 subunit was predominant among the dissociation products. The succinylation of 27 S iodoprotein showed essentially the same dissociation pattern as in the case of SDS treatment. The dissociation products of the protein preparations of different animals were qualitatively the same as those of thyroglobulin of the respective animals, confirming the hypothesis that 27 S iodoprotein was composed of two molecules of thyroglobulin. However, the extent of dissociation of 27 S iodoprotein measured by S-12 formation showed higher resistancy of the protein to the dissociating agents than that of thyroglobulin. The contents of sialic acid and hexose as well as iodoamino acids of 27 S iodoprotein were found to be the same as, or not far from, those of thyroglobulin. The dissociability and chemical composition of 27 S iodoprotein was discussed with reference to the subunit structure of the protein.

Effects of local immunization with glucosyltransferase fractions from Streptococcus mutans on dental caries in rats and hamsters

The effect of local immunization with glucosyltransferase enzymes of Streptococcus mutans on dental caries in conventional rats, hamsters, and gnotobiotic rats was studied. Injection of these animals with crude or defined glucosyltransferase enzyme preparations incorporated into complete Freund's adjuvant consistently resulted in the presence of antibody in saliva demonstrable by functional inhibition of enzymatic activity and binding of radioactive enzyme. Serum antibody was also present. Two experiments have been completed in conventional rats and one in gnotobiotic rats in which the animals were immunized with crude enzyme antigens. The immunized groups of animals always had lower mean caries scores than comparably sham-immunized or nonimmunized control groups. Hamsters immunized with a defined enzyme preparation, containing no more than three antigenic components (two of which were enzyme), also demonstrated significant reductions in mean caries scores. The numbers of lesions were also always lower in immunized animals. In some cases there were reductions in the numbers of S. mutans that could be recovered from the teeth of immunized, infected animals. The reductions in dental caries and lesions were greater on smooth dental surfaces than on occlusal surfaces, which might be explained as interference with adherence phenomena demonstrated by S. mutans. It is proposed that antibody interference affects dental caries caused by this organism.

Effects of denervation and reserpine on nexuses in the rat vas deferens

Permanganate-fixed vasa deferentia from rats were examined for the presence of nexal-like contacts by electron microscopy. There was a significantly greater incidence of nexuses (2X) in chronically denervated tissues (5-7 days) but not in tissues from reserpine-pretreated animals (1.0 mg/kg/day for 5-7 days). The results suggest that an increase in nexal regions may not be a general feature of postjunctional supersensitivity but rather may contribute to other denervation-induced changes in contractile response.

Antigenic relatedness of glucosyltransferase enzymes from streptococcus mutans

The antigenic relationship of glucosyltransferases (GTF) produced by different serotypes of Streptococcus mutans was studied by using a functional inhibition assay. Rat, rabbit, or hamster immune fluids, directed to cell-associated or supernatant-derived GTF, were tested against ammonium sulfate-precipitated culture supernatants containing GTF from seven strains of S. mutans representing six different serotypes. An antigenic relationship was shown to exist among GTF from serotypes a, d, and g, since both rat and rabbit antisera directed to serotype a or g GTF inhibited GTF of serotypes d and g similarly and both antisera also inhibited serotype a GTF. Furthermore, serum inhibition patterns indicated that GTF of serotypes c and e, and possibly b, are antigenically related to each other, but are antigenically distinct from GTF of serotype a, d, or g. Serum antibody directed to antigens other than enzyme (e.g., serotype-specific antigen or teichoic acid) had little effect on the inhibition assay. Salivas from rats immunized with cell-associated or supernatant-derived GTF exhibited low but consistent inhibition of GTF activity, which generally corresponded to the serum patterns. The sera of two groups of hamsters immunized with GTF (serotype g), enriched either in water-insoluble or water-soluble glucan synthetic activity, gave patterns of inhibition quite similar to those seen with sera from more heterogenous cell-associated or crude supernatant-derived GTF preparations. Both groups of hamster sera also gave virtually identical patterns, suggesting that the two enzyme forms used as antigen share common antigenic determinants. The results from the three animal models suggest that among the cariogenic organisms tested, two (serotypes a, d, g and b, c, e), or perhaps three (serotypes a, d, g; b; and c, e), different subsets of GTF exist that have distinct antigenic determinants within a subset.

Subunit structure of 27 S thyroid iodoprotein

The dissociation of thyroid 27 S iodoprotein by sodium dodecyl sulfate (SDS) and by succinic anhydride was investigated by means of ultracentrifugation and polyacrylamide gel electrophoresis. The iodoprotein obtained from either a human or hog was dissociated into three kinds of subunits (S-19, S-17 and S-12) by SDS treatment. At increased concentrations of SDS, the S-12 subunit was predominant among the dissociation products. The succinylation of 27 S iodoprotein showed essentially the same dissociation pattern as in the case of SDS treatment. This dissociation products of the protein preparations of different animals were qualitatively the same as those of thyroglobulin of the respective animals, confirming the hypothesis that 27 S iodoprotein was composed of two molecules of thyroglobulin. However, the extent of dissociation of 27 S iodoprotein measured by S-12 formation showed higher resistancy of the protein to the dissociating agents than that of thyroglobulin. The contents of sialic acid and hexose as well as iodoamino acids of 27 S iodoprotein were found to be the same as, or not far from, those of thyroglobulin; The dissociability and chemical composition of 27 S iodoprotein was discussed with reference to the subunit structure of the protein.

Probes of initial phosphorylation events in ATP synthesis by chloroplasts

Rapid mixing and quenching techniques have been used with chloroplasts activated by an acid-base transition or by light to assess the nature and characteristics of the substances initially labeled by inorganic [32P]phosphate during ATP synthesis. With light-activated chloroplast fragments, but not with acid-base-activated preparations, an initial rapid labeling of a small amount of ADP is observed. With the acid-base activated preparations a slower continued labeling of ADP occurs that is uncoupler-sensitive, that does not proceed via [gamma-32]ATP of the medium and for which medium ADP furnishes the AMP moiety. The results point to ADP as the initial acceptor of phosphate for ATP synthesis, with a slow side reaction in which bound ATP phosphorylates bound AMP to give a bound ADP. The phosphorylation of bound ADP by medium [32P]phosphate in the absence of added ADP is confirmed, but the reaction is too slow to serve as an intermediate in photophosphorylation. The appearance of label from [32P]phosphate in ATP in the acid-base transition at 25 degrees shows a lag of only about 3 to 7 ms, consistent with the absence of any phosphorylated intermediate. The lag is followed by a linear rate of [gamma-32]ATP formation that is about as fast as that observed in steady photophosphorylation, consistent with a proton gradient serving for transmission of energy from electron transfer reactions to the ATP-synthesizing complex.

Organization and development of brain stem auditory nuclei of the chicken: ontogeny of n. magnocellularis and n. laminaris

Nucleus magnocellularis (NM) and nucleus laminaris (NL) are, respectively, second- and third-order auditory nuclei in the chicken brain stem. In this report the morphogenesis of these nuclei is examined. The times of origin of the cells of these nuclei were studied with 3H-thymidine autoradiography. The number of cells in each nucleus and their rostro-caudal distribution within each nucleus was determined in Nissl-stained sections at 9, 11, 13, 15, 17, 19, and 21 days of incubation. For the above ages the volumes of NM and NL were also calculated planimetrically and the rostro-caudal distribution of volume within each nucleus was studied.

Immunization experiments using the rodent caries model

Taken together, the immunization experiments which have been performed in the rat caries model system appear to suggest a correlation between the presence of salivary antibody to S mutans and reductions in caries caused by these bacteria. However, the multifactorial nature of this disease does not permit at present the conclusion that the presence of this antibody is both necessary and sufficient to give rise to the demonstrated effects on pathogenesis. To clarify the role of salivary antibody, several refinements may be required in the current model. Immunization procedures that elicit only a local antibody response would both simplify interpretations of effects and would be more desirable for use as a vaccine. Such procedures might include intraductal installation of antigen in the parotid gland which has been demonstrated to result in this type of response. An additional refinement stems from the knowledge that the kinds of immunization procedures currently used stimulated both cellular immune and soluble antibody systems, potentially giving rise to a rather broad spectrum of immune responses. Therefore, it might be useful to study the effects on S mutans pathogenesis in rats in which certain of these responses have been repressed, for example, by thymectomy, antilymphocyte serum, and so on. Also, each of these approaches would be measurably enhanced by more sensitive techniques to monitor immunological events in the oral cavity. Refinements in the selection and use of relevant antigens of S mutans also are necessary to delineate the in vivo mechanism of immunological interference in the pathogenesis of cariogenic streptococci. Approaches involve the use of purified GTF antigens or cell surface antigens both in the investigation of these mechanisms in in vitro models using antibody specifically directed to these antigens and in rat immunization experiments using immunogenic preparations of these materials. In addition, alterations in the diet and challenge dosage of infecting cariogenic organisms might permit more sensitive detection of effects in vivo. Clearly, the evidence suggests immunological interference with S mutans pathogenesis in the rat model system. However, several gaps exist in our basic understanding of this interference and of the appropriate system in which to observe these effects. The potential significance of this phenomenon should spur efforts to fill these gaps to establish definitively the role of immunity as an ecological determinant in the oral cavity.