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The K1 capsular polysaccharide, a polymer of sialic acid, is an important virulence determinant of extraintestinal pathogenic Escherichia coli. The genes responsible for the synthesis and expression of the polysialic acid capsule of E. coli K1 are located on the 17-kb kps gene cluster, which is functionally divided into three regions. Central region 2 encodes proteins necessary for the synthesis, activation, and polymerization of sialic acid, while flanking regions 1 and 3 are involved in polymer transport to the cell surface. In this study, we identified two genes at the proximal end of region 2, neuD and neuB, which encode proteins with predicted sizes of 22.7 and 38.7 kDa, respectively. Several observations suggest that the neuB gene encodes sialic acid synthase. EV24, a neuB chromosomal mutant that expresses a capsule when provided exogenous sialic acid, could be complemented in trans by the cloned neuB gene. In addition, NeuB has significant sequence similarity to the product of the cpsB gene of Neisseria meningitidis group B, which is postulated to encode sialic acid synthase. We also present data indicating that neuD has an essential role in K1 polymer production. Cells harboring pSR426, which contains all of region 2 but lacks region 1 and 3 genes, produce an intracellular polymer. In contrast, no polymer accumulated in cells carrying a derivative of pSR426 lacking a functional neuD gene. Unlike strains with mutations in neuB, however, neuD mutants are not complemented by exogenous sialic acid, suggesting that NeuD is not involved in sialic acid synthesis. Additionally, cells harboring a mutation in neuD accumulated sialic acid and CMP-sialic acid. We also found no significant differences between the endogenous and exogenous sialyltransferase activities of a neuD mutant and the wild-type organism. NeuD shows significant similarity to a family of bacterial acetyltransferases, leading to the theory that NeuD is an acetyltransferase which may exert its influences through modification of other region 2 proteins.

Epidemiological, serological and in vitro phagocytosis experiments provide evidence that the newly discovered type 5 and type 8 capsular polysaccharides (CPs) are both virulence factors and protective antigens for bacteremia caused by Staphylococcus aureus. Neither type 5 nor type 8 CP elicited serum antibodies when injected into mice. These two CPs were bound to Pseudomonas aeruginosa exotoxin A (ETA) to form conjugates by using the synthetic scheme devised for the CP (Vi) of Salmonella typhi and of pneumococcus type 12F (A. Fattom, W. F. Vann, S. C. Szu, A. Sutton, X. Li, D. Bryla, G. Schiffman, J. B. Robbins, and R. Schneerson, Infect. Immun. 56:2292-2298, 1988; S. C. Szu, A. L. Stone, J. D. Robbins, R. Schneerson, and J. B. Robbins, J. Exp. Med. 166:1510-1524, 1987). Both S. aureus CP-ETA conjugates elicited a rise in CP antibodies. As components of conjugates, both S. aureus CPs acquired T-cell-dependent properties, as shown by their ability to respond to carrier priming and to stimulate booster responses. The conjugate-induced antibodies facilitated type-specific opsonization of S. aureus by human polymorphonuclear leukocytes. The conjugates also induced ETA antibodies which neutralized the native toxin in vitro. Clinical studies of these two conjugates for active or passive immunization of patients at risk for S. aureus bacteremia are planned.

The authors report on adverse events and sedation outcomes for an oral sedation regimen of chloral hydrate, meperidine and hydroxyzine with 100 percent oxygen, or O2, supplementation.In a five-year retrospective study, the authors examined 195 records of conscious sedation performed in 111 healthy children aged 24 to 48 months (mean, 47 months). The authors analyzed age, sex, weight, methods of drug delivery, waiting time after drug administration, treatment rendered, treatment time, adverse events, sedation outcomes and the number of visits needed to complete treatment using descriptive statistics, chi 2 tests, t test and analysis of variance.Adverse events--including vomiting, desaturation, prolonged sedation and an apneic event--occurred in 3 percent of all sedations and were minor. Seventy-two percent of sedations had satisfactory behavioral outcomes, 23 percent had unsatisfactory outcomes, and 5 percent of the cases were aborted because of disruptive behavior. Sex was not a significant factor for the success. Patient compliance with drinking medications (P = .013) and a longer waiting time after medication intake (P = .012) yielded better sedation outcomes.Minimal minor adverse events occurred with this sedation regimen. The success rate was 72 percent. Compliance with taking oral medications and waiting time appeared to be important factors in predicting sedation success.This oral sedation regimen offers reasonable outcomes with minimal adverse events under a strict protocol and use of O2 supplementation. The results also revealed associations that give guidance for case selection and outcome prediction.

Laser Doppler Flowmetry (LDF) has been shown to be valuable in monitoring revascularization of immature incisors following severe dental trauma. Several investigators have demonstrated the ability of LDF to record blood flow signals from vital tooth pulps. In this case report, LDF was used for a 7-year-old child patient following a severe luxation of tooth #9. During follow-up examinations the traumatized tooth was unresponsive to traditional vitality testing during the first 6 months; however, LDF indicated that revascularization had occurred much sooner. Until recently, CO2 ice has been the most effective method for sensitivity testing in trauma cases such as presented here. In this case, LDF gave us the assurance that we could defer invasive care during a critical time period when root canal therapy might have been initiated for this child patient.

The addition of sialic acid residues to glycoproteins can affect important protein properties including biological activity and in vivo circulatory half-life. For sialylation to occur, the donor sugar nucleotide cytidine monophospho-sialic acid (CMP-SA) must be generated and enzymatically transferred to an acceptor oligosaccharide. However, examination of insect cells grown in serum-free medium revealed negligible native levels of the most common sialic acid nucleotide, CMP-N-acetylneuraminic acid (CMP-Neu5Ac). To increase substrate levels, the enzymes of the metabolic pathway for CMP-SA synthesis have been engineered into insect cells using the baculovirus expression system. In this study, a human CMP-sialic acid synthase cDNA was identified and found to encode a protein with 94% identity to the murine homologue. The human CMP-sialic acid synthase (Cmp-Sas) is ubiquitously expressed in human cells from multiple tissues. When expressed in insect cells using the baculovirus vector, the encoded protein is functional and localizes to the nucleus as in mammalian cells. In addition, co-expression of Cmp-Sas with the recently cloned sialic acid phosphate synthase with N-acetylmannosamine feeding yields intracellular CMP-Neu5Ac levels 30 times higher than those observed in unsupplemented CHO cells. The absence of any one of these three components abolishes CMP-Neu5Ac production in vivo. However, when N-acetylmannosamine feeding is omitted, the sugar nucleotide form of deaminated Neu5Ac, CMP-2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (CMP-KDN), is produced instead, indicating that alternative sialic acid glycoforms may eventually be possible in insect cells. The human CMP-SAS enzyme is also capable of CMP-N-glycolylneuraminic acid (CMP-Neu5Gc) synthesis when provided with the proper substrate. Engineering the CMP-SA metabolic pathway may be beneficial in various cell lines in which CMP-Neu5Ac production limits sialylation of glycoproteins or other glycans.

This study was performed to compare the effects of nitrous oxide/oxygen (N2O/O2) versus oxygen (O2) as adjuncts to an oral narcotic regimen for pediatric conscious sedation.Using a randomized double-blind crossover design, 19 children (mean age 41 +/- 8.6 months) were sedated with chloral hydrate (50 mg/kg), meperidine (1.5 mg/kg) and hydroxyzine pamoate (25 mg) for two appointments. Patients were assigned randomly to receive 100% O2 at one visit and 50% N2O/O2 at the other. Physiologic parameters were measured in five-minute intervals, including respiratory rate, pulse rate (PR), oxyhemoglobin saturation (SpO2) and end-tidal carbon dioxide. Data analyses focused on true desaturations and apnea, level of sedation and sedation outcomes.There were no differences in PR, SpO2 and risk of desaturation between the inhalation agents. The level of sedation was deeper and the sedation outcomes were better in the N2O/O2 group.N2O/O2 deepened the sedation while improving its success with minimal alteration in physiologic parameters.

The purpose of this pilot study is to report a cost comparison of general anesthesia (GA) versus oral conscious sedation (CS) for the treatment of pediatric dental patients.The study sample included 22 children whose parents/guardian selected GA care for their child. Selection criteria limited inclusion to healthy children (ASA I) ages 24-60 m.o. The subjects acted as their own comparison group to an estimation CS model. Models were developed to assess societal costs for treatment under GA and CS. Treatment rendered was equalized using the dental Relative Based Value Units Scale (RBVU).Ordinary Least Squares Regression analysis techniques showed the association of RBVU to the total societal costs of GA and CS to be significant (P0.01) with an adjusted R2 of .64 and .78 respectively. When regression lines were plotted, the intersection represented RBVU level at which societal costs of GA and CS were the same.Under the conditions of this pilot study, it is concluded that CS costs exceed GA costs at a RBVU level of 66.4, which would equate to more than three CS appointments.

To characterize the patterns of dental care in the North Carolina (NC) Medicaid Program for three- and eight-year-old children who began dental treatment in the 1985-86 and 1990-91 groups. We also compared the children's patterns of care by provider (general dentists versus pediatric dentists).Our extensive data set included claims, enrollment, and provider data. Children were assigned to one of five categories or patterns of care as follows: complete care, general anesthesia care, sporadic care, emergency only care, and no care. Statistical comparisons of the variables age, cohort year, and provider groups were made.The use of Medicaid dental services by both age groups was severely limited in both yearly cohorts. Pediatric dentists tended to provide more complete and less sporadic care for both age groups and both yearly cohorts.Financing dental care through Medicaid results in very low levels of complete care among enrollees, and any plan that limits referral to pediatric dentists might adversely affect the number of enrollees who receive complete care.

This study compared the effect of supplemental oxygen (O2) on pediatric patients' apnea status and oxyhemoglobin saturation during: 1) conscious sedation for dental procedures and 2) the recovery period following sedation.Fourteen child patients (mean age 42 months) sedated with 50 mg/Kg chloral hydrate, 25 mg hydroxyzine pamoate, and 1.5 mg/Kg meperidine were treated for two separate appointments. The patients received supplemental O2 via nasal cannulae at random at one of the two appointments. Following the operative period, all patients were monitored sitting upright for an additional 15 min.Intraoperative results showed that the risk of apnea was 39% (11/28), with apneic events distributed equally between O2 and non-O2 supplemented sedations. The overall risk of desaturation was 29% (8/28). Mean SpO2 was always elevated with O2 supplementation and the mean difference in O2 versus non-O2 was statistically significant. The risk of apnea in the postoperative period was 7% (1/14) for both the non-O2 and O2-supplemented patients. The risk of desaturation in the postoperative period was 11% (3/28) with one desaturation in a non-O2 and two desaturations in O2-supplemented patients.We conclude that intraoperative O2 supplementation prevents desaturations even in the presence of apnea during pediatric conscious sedation.

Escherichia coli K1 produces a capsular polysaccharide of alpha(2-8) poly-N-acetylneuraminic acid. This polysaccharide is an essential virulence factor of these neuropathogenic bacteria. The genes necessary for the synthesis of neuNAc were localized to a plasmid containing the neuBAC genes of the K1 gene cluster. Cells harboring the neuB+ allele in an aldolase (nanA-) negative background produce neuNAc in vivo. Enzymatic synthesis of neuNAc could be demonstrated in extracts of cells harboring an expression plasmid (pNEUB) containing the neuB gene alone. NeuNAc synthetase was purified to homogeneity from extracts of cells harboring pNEUB. The molecular weight of the purified enzyme is 40 kDa, similar to that predicted by the nucleotide sequence of the neuB gene. The amino terminal sequence of the purified protein matches that predicted by the nucleotide sequence of the neuB gene. NeuNAc synthetase catalyzes the formation of neuNAc as indicated by its coupling to the CMP-neuNAc synthetase reaction. The enzyme condenses manNAc and PEP with the release of phosphate. The E. coli neuNAc synthetase is specific for manNAc and PEP, unlike rat liver enzyme that utilizes N-acetylmannosamine-6-phosphate to form neuNAc-9-PO4. This represents the first report of a purification of a sialic acid synthetase from either a eukaryotic or prokaryotic source to homogeneity. These experiments clearly demonstrate an aldolase-independent sialic acid synthetase activity in E. coli K1.

The purpose of this study was to report trends in dentists' participation in the North Carolina Medicaid program. Medicaid claims files for dental users younger than age 21 were analyzed for seven fiscal years (FY) from 1986 to 1992. Over the study period, the number of pediatric dentists filing any Medicaid claims remained constant but the number of participating general dentists decreased slightly. Intensity of participation, as measured by mean annual reimbursement and mean number of children treated per dentist, increased from FY 89 to 92 for both provider groups. The mean value of services provided for each dental users also increased slightly during the same period. The data revealed over time pediatric dentists treated a larger proportion of the youngest Medicaid dental users.

The primary advantages of glass ionomer restorative materials are adhesion to tooth structure and release of fluoride. A new material has been recently introduced for the restoration of cervical lesions and Class I defects in primary teeth. The material combines the properties of glass ionomers with the advantages of a single-component, light-activated composite resin and is known as a "compomer". This new material contains two resins, instead of the acidic polymers found in conventional glass ionomers. The restorative material releases fluoride and can be infected directly into the cavity. With its own bonding agent, the compomer offers a simple and relatively rapid technique. The learning objective of this paper is to describe the utilization of the new restorative material in conjunction with a bonding agent to restore conservative cavity preparations in primary molars. Two clinical cases are used to illustrate the presentation.

The first purpose of this study was to compare traditional monitoring methods to electronic instruments for monitoring physiologic parameters during conscious sedation of pediatric dental patients. Traditional methods included careful visual assessment of skin color, airway patency and chest movements, and auscultation of breath and heart sounds using a precordial stethoscope; electronic instruments included the capnograph and pulse oximeter. The second purpose of the study was to examine the potential of the capnograph to provide more advanced warning than the pulse oximeter for respiratory compromise. Thirty-nine children (mean age 39 months) received an oral sedative regimen of chloral hydrate, hydroxyzine pamoate, and meperidine and all were supplemented with 100% oxygen via nasal cannula throughout their sedations. One investigator used traditional monitoring and the other used electronic--both monitored simultaneously while being shielded (blinded) from each other. Electronic monitoring yielded a false alert rate of 88% compared with 73% for traditional monitoring. Ten confirmed episodes of respiratory compromise were identified electronically and only three were identified by traditional monitoring. All of the 10 confirmed respiratory compromise episodes were detected by capnography; none were detected by oximetry. During these 39 pediatric sedations using a narcotic drug regimen and 100% oxygen supplementation, there were no true desaturations.

The gene encoding for the CMP-NeuNAc synthetase enzyme of Neisseria meningitidis group B was cloned by complementation of a mutant of Escherichia coli defective for this enzyme. The gene (neuA) was isolated on a 4.1-kb fragment of meningococcal chromosomal DNA. Determination of the nucleotide sequence of this fragment revealed the presence of three genes, termed neuA, neuB, and neuC, organized in a single operon. The presence of a truncated ctrA gene at one end of the cloned DNA and a truncated gene encoding for the meningococcal sialyltransferase at the other confirmed that the cloned DNA corresponded to region A and part of region C of the meningococcal capsule gene cluster. The predicted amino acid sequence of the meningococcal NeuA protein was 57% homologous to that of NeuA, the CMP-NeuNAc synthetase encoded by E. coli K1. The predicted molecular mass of meningococcal NeuA protein was 24.8 kDa, which was 6 kDa larger than that formerly predicted (U. Edwards and M. Frosch, FEMS Microbiol. Lett. 96:161-166, 1992). Purification of the recombinant meningococcal NeuA protein together with determination of the N-terminal amino acid sequence confirmed that this 24.8-kDa protein was indeed the meningococcal CMP-NeuNAc synthetase. The predicted amino acid sequences of the two other encoded proteins were homologous to those of the NeuC and NeuB proteins of E. coli K1, two proteins involved in the synthesis of NeuNAc. These results indicate that common steps exist in the biosynthesis of NeuNAc in these two microorganisms.

In a prospective longitudinal study, 1099 first grade children from Aiken, South Carolina, and 1086 children from Portland, Maine, were examined annually for 3 years. Caries prevalence and dmfs incidence were determined. The mean dmfs in Portland children was 2.9. In Aiken, white children had a mean dmfs of 8.4, and black children had a mean dmfs of 10.2. The mean 3-year primary tooth caries increment was 1.5 surfaces in the Portland cohort 3.3 surfaces in the Aiken white cohort and 2.8 surfaces in the Aiken black cohort. These increments were divided evenly between interproximal and fissure surfaces. Twenty percent of the children in Portland had 75% of the caries; in Aiken, 20% of the children had 60% of the caries. This distribution suggests a high-risk group that could be targeted for aggressive caries prevention efforts if risk factors can be identified.

A 20-day-old black male infant with two rare posterior natal teeth was referred for examination and care. Oral radiographs suggested that the teeth were the right and left maxillary primary molars. The hypermobile teeth and associated suspicious soft tissue masses were removed. Histologic examination revealed irregular tooth structures and infiltrate consistent with inflamed dental follicles.

A surface polysaccharide antigen of Moraxella nonliquefaciens, reported to be cross-reactive with the capsular polysaccharides of group B Neisseria meningitidis and Escherichia coli K1 (K. Błvre, K. Bryn, O. Closs, N. Hagen, and L. O. Froholm, NIPH Ann. 6:65-73, 1983), was isolated, purified, and characterized chemically, immunologically, and by nuclear magnetic resonance. This polysaccharide was shown to be a linear homopolymer of alpha (2----8)-linked N-acetylneuraminic acid, identical to the capsular polysaccharide of group B N. meningitidis and O-acetyl-negative variants of E. coli K1.

This study evaluated two oral sedative regimens for the conscious sedation of pediatric dental patients (mean age 37.0 months) unmanageable by traditional behavior management techniques. Regimen A included chloral hydrate (Noctec--E.R. Squibb and Sons, Princeton, NJ) at 50 mg/kg with 25 mg hydroxyzine pamoate (Vistaril--Pfizer Laboratories, New York, NY), plus meperidine (Demerol--Winthrop-Breon, New York, NY) at 1.5 mg/kg. Regimen B included chloral hydrate at 50 mg/kg with 25 mg hydroxyzine pamoate. In a crossover research design, 10 patients were assigned randomly to receive one regimen, to be followed by the alternative regimen during the second appointment. The primary purpose of this study was to determine if meperidine would improve patient behavior, and increase the prevalence of respiratory compromise. A secondary purpose of the study was to develop an objective method to assess behavior during the conscious sedation of pediatric dental patients. Results revealed that the addition of oral meperidine to chloral hydrate and hydroxyzine pamoate resulted in improved behavior (P less than 0.01) during local anesthetic injection, rubber dam delivery, and the operative dental procedure. There was no increase in the prevalence of respiratory compromise with the addition of meperidine.

Conjugates of an uronic acid-containing capsular polysaccharide (CP), pneumococcous type 12F (Pn12F) bound to diphtheria toxoid (DT), were studied for safety and immunogenicity in adult volunteers. In mice, these conjugates, prepared with the same lot of DT and Pn12F-40234-006, a homogenous CP of high molecular weight, or Pn12-812408, a polydisperse CP with lower-molecular-weight material, were more immunogenic than the Pn12F alone and had T-cell dependent properties (A. Fattom, W. F. Vann, S.C. Szu, A. Sutton, X. Li, B. Bryla, G. Schiffman, J. B. Robbins, and R. Schneerson, Infect. Immun. 56:2292-2298, 1988). Adult volunteers, randomized into three groups, were injected either with one of these two conjugates or with Pnu-Imune, the 23 valent pneumococcus vaccine containing 25 micrograms of Pn12F as one of its components. Volunteers were injected two times, 4 weeks apart, with the Pn12F-DT conjugates and once with the Pnu-Imune. Side reactions following injection of the conjugates of Pnu-Imune were mild and short-lived. At 4 weeks and at 7 months after the first injection, higher levels of Pn12F antibodies were found in the volunteers injected with the conjugates than in the Pnu-Imune group (P less than 0.001). The conjugate prepared with the higher-molecular-weight Pn12F elicited higher levels of antibodies than the conjugate prepared with a lower-molecular-weight Pn12F preparation (P = 0.05). Both conjugates elicited about a 13-fold rise in DT antibodies.

This study was designed to develop an indirect method for measuring the time required for restoration placement; and to compare the operator time required for placement of amalgam and composite resins in posterior teeth in children. Forty children, aged seven to nine years old, were selected to participate. Either amalgam or an experimental resin was used to restore the primary and permanent molars. All restorations and sealants were completed under the rubber dam. Each restorative appointment was videotaped with a color video camera mounted on the ceiling. Ninety-six restorative procedures were reviewed and evaluated for the amount of time necessary to accomplish them. The Class I permanent molar composite restoration required 35 percent more insertion and finishing time than did the amalgam.

The Escherichia coli CMP-N-acetylneuraminic acid (CMP-NeuAc) synthetase gene is located on a 3.3-kilobase (kb) HindIII fragment of the plasmid pSR23 which contains the genes for K1 capsule production (Vann, W. F., Silver, R. P., Abeijon, C., Chang, K., Aaronson, W., Sutton, A., Finn, C. W., Lindner, W., and Kotsatos, M. (1987) J. Biol. Chem. 262, 17556-17562). The CMP-NeuAc synthetase gene expression was increased 10-30-fold by cloning of a 2.7-kb EcoRI-HindIII fragment onto the vector pKK223-3 containing the tac promoter. The complete nucleotide sequence of the gene encoding CMP-NeuAc synthetase was determined from progressive deletions generated by selective digestion of M13 clones containing the 2.7-kb fragment. CMP-NeuAc synthetase is located near the EcoRI site on this fragment as indicated by the detection of an open reading frame encoding a 49,000-dalton polypeptide. The amino- and carboxyl-terminal sequences of the encoded protein were confirmed by sequencing of peptides cleaved from both ends of the purified enzyme. The nucleotide deduced amino acid sequence was confirmed by sequencing several tryptic peptides of purified enzyme. The molecular weight is consistent with that determined from sodium dodecyl sulfate-gel electrophoresis. Gel filtration and ultracentrifugation experiments under nondenaturing conditions suggest that the enzyme is active as a 49,000-dalton monomer but may form aggregates.

A cell-free system was established to study the biosynthesis of group C meningococcal capsular polysaccharide, an alpha-2 leads to 9-linked N-acetylneuraminic acid (NeuAc) homopolymer containing O-acetyl groups at either C7 or C8. Sialyltransferase activity, isolated from group C meningococcus strain C-11, catalyzed incorporation of [14C]NeuAc from CMP (CMP--[14C]NeuAc) into polymeric form. This sialyltransferase was stimulated by addition of meningococcus group C and Escherichia coli K92 capsular polysaccharides, the latter being an alpha-2 leads to 8- and alpha-2 leads to 9-linked NeuAc heteropolymer. Group C meningococcal sialyltransferase did not require divalent ions but was stimulated by Mn2+. Attempts to demonstrate a lipid-soluble intermediate in the biosynthesis of this NeuAc polymer were unsuccessful. Meningococcal group C sialyltransferase incorporated NeuAc into a membrane-associated product. The polysaccharide can be extracted from the membrane-bound fraction with Triton X-100. The newly synthesized polysaccharide coprecipitates with authentic group C antigen in meningococcal group C antiserum and is degraded by sodium metaperiodate, indicating that the NeuAc polymer synthesized by the cell-free system consists of alpha-2 leads to 9 linkage. Meningococcal group C spheroplast membranes contain an O-acetylase that can catalyze the transfer of acetyl groups from acetyl coenzyme A to the in vitro-synthesized polysaccharide.

A photoreactive, radiolabeled pyrimidine nucleotide, 3'-O-(4-benzoyl)benzoylcytidine 5'-triphosphate was synthesized from benzoylbenzoic acid and radiolabeled CTP. Benzoylbenzoyl-[5-3H]CTP could substitute for CTP, in an enzymatic reaction with N-acetylneuraminic acid catalyzed by Escherichia coli or rat liver CMP-NeuAc synthetase, to yield radiolabeled benzoyl-benzoyl-CMP-NeuAc. E. coli CMP-NeuAc synthetase could be specifically radiolabeled using benzoylbenzoyl-[alpha-32P]CTP as a photoaffinity label. This specific covalent binding occurred using enzyme preparations of different degrees of purity. These results suggest that benzoylbenzoic acid derivatives of pyrimidines should be of general use in the identification and active site mapping of pyrimidine-requiring proteins and enzymes. These include glycosyltransferases, sugar nucleotide synthetases, and transporters, and enzymes participating in the conjugation of bile acids and biosynthesis of nucleic acids and choline nucleotides.

The structural basis for the cross-reactivity between theEscherichia coli K13, K20 and K23 capsular polysaccharides is the →)-β-ribofuranosyl-(1→7)-β-2-keto-3-deoxyoctonate polymer. Monoclonal antibodies againstE. coli K13 which require O-acetyl-2-keto-3-deoxyoctonate for binding were further investigated. Such antibodies, of both the IgG and the IgM isotype, opsonizedE. coli K13in vitro and protected against intraperitoneal infection in mice as well as ascending pyelonephritis in rats. A monoclonal IgG1 anti-idiotype, specific for the K13 polysaccharide combining site of a protective IgM idiotype, primed for protection against intraperitoneal infection with liveE. coli K13 following K13 injections at four as well as 12 weeks of age. the K13 polysaccharide alone did not immunize and protect. The monoclonal anti-K13 idiotype only primed for protection at four weeks of age. These findings suggest a strong effect of a single idiotype on the outcome of a bacterial infection.

A polysaccharide, antigenically and structurally related to meningococcal group A polysaccharide, was isolated from Bacillus pumilus Sh-17. This enteric bacterium has been implicated as a source of natural meningococcal group A immunity (Myerowitz et al., 1973). The B. pumilus polysaccharide was composed of a homopolymer of (1-6)-N-acetyl-manosamine-1-phosphate, glycerol phosphate teichoic acid-containing N-acetylglucosamine and alkali-labile alanine esters, and a mucopeptide. The cross-reaction was due to the poly-(1-6)-N-acetyl-mannosamine-1-phosphate in the B. pumilus and the meningococcal group A polysaccharides, based on the following evidence. Both polysaccharides contained N-acetyl-mannosamine phosphate. Periodate oxidized the mannosamine phosphate residues of the polysaccharide and destroyed their precipitating activity with meningococcal group A antiserum. Mild acid treatment released phosphomonoesters and destroyed the meningococcal group A precipitating activity of both polysaccharides. N-acetyl-mannosamine-6-phosphate inhibited the precipitation reaction between strain Sh-17 and meningococcal group A antisera. Only mannosamine phosphate was detected in trichloroacetic acid extracts of Sh-17 polysaccharide and meningococcal group A antigen-antibody precipitates.

This paper compares and contrasts two clinical teaching systems in undergraduate pedodontics: the block system and the total patient care system (TPC). Descriptions and rationales are given for specific block and TPC systems at two universities. Theoretical advantages and disadvantages are reviewed. Clinical data are presented that represent experiences of the graduating classes of 1978 at The University of Iowa (block) and the University of North Carolina (TPC). From this limited sample there appears to be little quantitative evidence that one system is better than the other when examining clinical experiences in the two schools studied.

Soft tissue outlines from profile radiographs, with or without supplementary photographs, do not provide enough information to reliably assess the underlying skeletal pattern in children 8 and 12 years old. Assessment was less reliable at 8 than at 12 years of age. Prognathic patterns were not as readily identified as retrognathic patterns. Specialty training did not affect the correctness of these limited assessments.

A photoreactive, radiolabeled pyrimidine nucleotide, 3'-O-(4-benzoyl)benzoylcytidine 5'-triphosphate was synthesized from benzoylbenzoic acid and radiolabeled CTP. Benzoylbenzoyl-[5-3H]CTP could substitute for CTP, in an enzymatic reaction with N-acetylneuraminic acid catalyzed by Escherichia coli or rat liver CMP-NeuAc synthetase, to yield radiolabeled benzoyl-benzoyl-CMP-NeuAc. E. coli CMP-NeuAc synthetase could be specifically radiolabeled using benzoylbenzoyl-[alpha-32P]CTP as a photoaffinity label. This specific covalent binding occurred using enzyme preparations of different degrees of purity. These results suggest that benzoylbenzoic acid derivatives of pyrimidines should be of general use in the identification and active site mapping of pyrimidine-requiring proteins and enzymes. These include glycosyltransferases, sugar nucleotide synthetases, and transporters, and enzymes participating in the conjugation of bile acids and biosynthesis of nucleic acids and choline nucleotides.

Capsular types 5 and 8, which account for about 70% of Staphylococcus aureus strains isolated from the blood of patients, resisted in vitro phagocytosis by human polymorphonuclear leukocytes (PMN). Antisera and monoclonal antibody to type 5 and 8 capsular polysaccharides (CPS) induced type-specific in vitro phagocytosis of capsulated organisms by PMN. Antibodies directed against the O-acetyl moiety of the type 8 CPS were more effective in inducing phagocytosis of type 8 organisms by PMN. Either type-specific antiserum or monoclonal antibody reactive with the native O-acetylated type 8 CPS was most effective in inducing in vitro phagocytosis of type 8 organisms by PMN. These results provide further evidence that CPS of S. aureus are associated with host immunity to this organism.

N-Acetylneuraminic acid cytidylyltransferase (EC 2.7.7.43) (CMP-NeuAc synthetase) catalyzes the formation of cytidine monophosphate N-acetylneuraminic acid. We have purified CMP-NeuAc synthetase from an Escherichia coli O18:K1 cytoplasmic fraction to apparent homogeneity by ion exchange chromatography and affinity chromatography on CDP-ethanolamine linked to agarose. The enzyme has a specific activity of 2.1 mumol/mg/min and migrates as a single protein and activity band on nondenaturing polyacrylamide gel electrophoresis. The enzyme has a requirement for Mg2+ or Mn2+ and exhibits optimal activity between pH 9.0 and 10. The apparent Michaelis constants for the CTP and NeuAc are 0.31 and 4 mM, respectively. The CTP analogues 5-mercuri-CTP and CTP-2',3'-dialdehyde are inhibitors. The purified CMP-N-acetylneuraminic acid synthetase has a molecular weight of approximately 50,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The gene encoding CMP-N-acetylneuraminic acid synthetase is located on a 3.3-kilobase HindIII fragment. The purified enzyme appears to be identical to the 50,000 Mr polypeptide encoded by this gene based on insertion mutations that result in the loss of detectable enzymatic activity. The amino-terminal sequence of the purified protein was used to locate the start codon for the CMP-NeuAc synthetase gene. Both the enzyme and the 50,000 Mr polypeptide have the same NH2-terminal amino acid sequence. Antibodies prepared to a peptide derived from the NH2-terminal amino acid sequence bind to purified CMP-NeuAc synthetase.

After promising results were achieved with an experimental method for teaching the acquisition of psychomotor skills to dental students, a long-term follow-up study evaluated the lasting effects of that method using preclinical and clinical grades, as well as an assessment of students' clinical technical performance. Though the experimental teaching method had a significant effect on student performance in the initial preclinical activities, the differences between the control and experimental groups diminished as the students progressed through subsequent preclinical courses. No significant differences were found in measures obtained during the clinical years.