Dentigerous cysts involving permanent incisors: four case reports

Four cases of dentigerous cysts involving permanent incisors are reported. In each case the primary predecessor had been traumatized, was discoloured and suspected of being non-vital. Epithelial proliferation of the follicular tissues induced by chronic periapical inflammation of the predecessors is suggested as the most likely pathogenesis of cystic transformation in these cases. Regular radiographic review of discoloured primary incisors is recommended.

Differential stem cell contributions to thymocyte succession during development of Xenopus laevis

The contribution of two embryonic stem cell compartments to the developing thymus in the amphibian Xenopus was examined throughout the larval, postmetamorphic, and adult periods. Hematopoietic chimeras were produced by transplanting either the ventral blood islands (VBI) or the dorsal stem cell compartment (DSC) from diploid donors onto triploid hosts. The DNA content of isolated nuclei harvested from the thymus and circulating E populations was analyzed using propidium iodide staining and flow cytometry. The DNA content of mitotic figures derived from PHA reactive splenocytes was analyzed using the Feulgen reaction and microdensitometry. These data suggested that both the VBI and DSC contribute to the thymocyte populations from the earliest developmental stages examined. Moreover, the contribution of both stem cell compartments was cyclic. However, the periods of these cycles were different. Both VBI- and DSC-derived cells entered the thymus 4 days postfertilization. VBI-derived thymocytes were at a minimum at 28 days postfertilization, reached a maximum at 35 days postfertilization and a second minimum at 42 days postfertilization. However, DSC-derived cells reached a maximum at 28 days, a minimum at 35 days, and a second maximum at 42 days. The PHA-reactive splenocyte population followed a similar temporal pattern. In contrast, the VBI-derived E population was at a maximum during early development and steadily declined throughout the larval period. DSC-derived E were undetectable during early development but steadily increased throughout the larval period. Both VBI- and DSC-derived hematopoietic cells persisted after metamorphosis and contributed to all populations examined in adult frogs. Because of temporal differences in the VBI and DSC contributions to the developing thymus, these data suggest heterogeneity within the thymocyte population associated with the embryonic origin of the colonizing stem cells.

Differential stem cell contributions to thymocyte succession during development of Xenopus laevis

The contribution of two embryonic stem cell compartments to the developing thymus in the amphibian Xenopus was examined throughout the larval, postmetamorphic, and adult periods. Hematopoietic chimeras were produced by transplanting either the ventral blood islands (VBI) or the dorsal stem cell compartment (DSC) from diploid donors onto triploid hosts. The DNA content of isolated nuclei harvested from the thymus and circulating E populations was analyzed using propidium iodide staining and flow cytometry. The DNA content of mitotic figures derived from PHA reactive splenocytes was analyzed using the Feulgen reaction and microdensitometry. These data suggested that both the VBI and DSC contribute to the thymocyte populations from the earliest developmental stages examined. Moreover, the contribution of both stem cell compartments was cyclic. However, the periods of these cycles were different. Both VBI- and DSC-derived cells entered the thymus 4 days postfertilization. VBI-derived thymocytes were at a minimum at 28 days postfertilization, reached a maximum at 35 days postfertilization and a second minimum at 42 days postfertilization. However, DSC-derived cells reached a maximum at 28 days, a minimum at 35 days, and a second maximum at 42 days. The PHA-reactive splenocyte population followed a similar temporal pattern. In contrast, the VBI-derived E population was at a maximum during early development and steadily declined throughout the larval period. DSC-derived E were undetectable during early development but steadily increased throughout the larval period. Both VBI- and DSC-derived hematopoietic cells persisted after metamorphosis and contributed to all populations examined in adult frogs. Because of temporal differences in the VBI and DSC contributions to the developing thymus, these data suggest heterogeneity within the thymocyte population associated with the embryonic origin of the colonizing stem cells.

Spinal mechanisms of delta 9-tetrahydrocannabinol-induced analgesia

Cannabinoids have been demonstrated to be effective antinociceptive agents when given intravenously. In order to determine whether spinal antinociception can be achieved while minimizing psychotomimetic properties, the pharmacological activity of delta 9-tetrahydrocannabinol (THC) was evaluated after intrathecal injection in male ICR mice. Although delta 9-THC produced potent antinociception, it also caused hypoactivity, hypothermia, and catalepsy. Intrathecal administration of delta 9-THC in mice which had their spinal cord transected at T12 also produced potent antinociception suggesting a spinal component to the antinociceptive effect. Biodispositional studies of [3H]delta 9-THC demonstrated that brain levels of the drug following intrathecal injection in spinally transected animals were not sufficient to produce the antinociceptive effect. These studies suggest the involvement of a spinal component in the antinociceptive action of the cannabinoids.

A comparison between a 1986 and 1989 cohort of inner-city adolescent females on knowledge, beliefs, and risk factors for AIDS

In order to assess changes from 1986 to 1989 in knowledge, beliefs, and risk factors for AIDS, the responses of inner-city adolescent girls were compared. Although 63% of the 1989 cohort received AIDS education in school, the base knowledge of the two cohorts was not markedly different. Between 1986 and 1989, the number of sexual partners increased for adolescents of all ethnic groups, yet concerns about AIDS showed a decline. Those adolescents who had the highest number of sexual partners were also those who had the most knowledge and most concerns about AIDS. Implications for preventive education focus on ethnic diversity and gaps between adolescent knowledge and behavior.

Knowledge, beliefs, and behavioral risk factors for human immunodeficiency virus infection in inner city adolescent females

Five hundred and ten inner city adolescent girls requesting reproductive health services were surveyed about their knowledge and beliefs concerning human immunodeficiency virus (HIV) infection. Each patient's survey responses were examined in relation to number of sexual partners and history of a sexually transmitted disease (STD). Adolescents with the greatest concerns and fears of contracting acquired immune deficiency syndrome (AIDS) were those with multiple sexual partners. Those with the joint effects of multiple sexual partners and a history of STD were the most likely to acknowledge their potential for HIV infection and have a behavioral basis for it. Sexual behaviors within this age group are highlighted and programmatic interventions are suggested.

In vitro formation of glutathione conjugates of the dimethylester of bilirubin

Rat hepatic microsomes catalyzed the formation of two distinct glutathione conjugates of bilirubin dimethylester (DMB). The two conjugates were identical to those isolated from the bile of Gunn rats infused with DMB. The microsomal reaction was dependent on NADPH, oxygen and glutathione and was inhibited by nitrogen and the cytochrome P450 inhibitors metyrapone, 1-benzyl-imidazole, and alpha-naphthoflavone. Conjugate formation was inducible with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) but not phenobarbital pretreatment. The rate of formation of conjugates was not affected by washings of the microsomal pellet or by the presence of superoxide dismutase and/or catalase. Cation fast atom bombardment mass spectrometry (FAB/MS) of the conjugates indicated a molecular ion of 937 atomic mass units (amu). Fragmentation revealed a loss of 307 amu, consistent with glutathione, and a residual mass of 629 amu suggesting a hydroxylated derivative of DMB (612 amu). Cation FAB/MS/MS of conjugates formed in vitro under an atmosphere of oxygen-16 and oxygen-18 demonstrated the incorporation of molecular oxygen by a difference of 2 amu in the respective molecular ions. Our results suggest that DMB is oxidized by the cytochrome P450 IA gene family to an epoxide intermediate which is then subsequently conjugated with glutathione.

Identification of glutathione conjugates of the dimethyl ester of bilirubin in the bile of Gunn rats

The Gunn rat, which is deficient in the UDP-glucuronosyltransferase for bilirubin, promptly excreted polar conjugates of the dimethyl ester of bilirubin in bile after intravenous infusion of this ester. The conjugates proved to be monoglutathione thioether adducts of the vinyl groups of the parent tetrapyrrole. High performance liquid chromatographic analysis of the conjugates as their dipyrrolic azosulfanilates demonstrated that only one of the dipyrroles of each tetrapyrrole was conjugated. The nonconjugated dipyrrole eluted as either the methyl endo- or exovinyl azodipyrrole. The amino acid composition of the pigments was consistent with that of a monoglutathione conjugate. NMR spectroscopy of the two major pigments demonstrated the loss of the proton signals of the C-18 vinyl group, indicating it to be the site of conjugation. Cation fast atomic bombardment tandem mass spectrometry demonstrated a molecular ion, [M + H]+, of m/z 937, which fragmented with a loss of 307 atomic mass units, consistent with glutathione. A molecular ion of m/z 807 was observed for the conjugate treated with gamma-glutamyltranspeptidase, consistent with the loss of glutamate. The mass spectrometry data indicated that the conjugates also contained a functional group whose mass was equivalent to hydroxyl, suggesting initial formation of an epoxide, which then reacts with glutathione. Pretreatment of the rat with 2,3,7,8-tetrachlorodibenzo-p-dioxin to induce cytochrome P-450 resulted in a 6-fold increase of the biliary excretion of the glutathione conjugates. Such induction also resulted in the excretion of a glutathione conjugate of bilirubin itself.

Glutathione conjugation with phosphoramide mustard and cyclophosphamide. A mechanistic study using tandem mass spectrometry

The conjugations of cyclophosphamide and of phosphoramide mustard with glutathione are shown to be catalyzed by hepatic cytosolic glutathione-S-transferases. Cyclophosphamide conjugation is also catalyzed by microsomal glutathione-S-transferases, both in intact microsomes and after solubilization and immobilization. Deuterium isotope labels are used to test whether chloride is directly displaced by glutathione in the enzyme-catalyzed conjugations, or whether conjugation takes place via symmetrical cyclic aziridinium ions. Tandem mass spectrometry with high energy collisional activation is shown to provide reliable analysis of the isotope-labeling patterns in the conjugated products. This experiment leads to the conclusion that the aziridinium ion is opened in the conjugation of phosphoramide mustard in both the enzyme-catalyzed and the chemical reactions. Cyclophosphamide, on the other hand, is shown to be conjugated through direct displacement of chloride.

Sexually transmitted disease treatment and return for test of cure of adolescents in a family planning clinic

This retrospective study assessed the return for treatment and test-of-cure rates for gonorrhea and chlamydial infection among 154 adolescents and young adults attending a family planning clinic. Eighty-four percent returned for treatment and 57% of those returned for a test of cure. No statistical differences in race/ethnicity, marital status, gravida, age, presence of symptoms, or type of infection were found between those returning and those not returning for treatment. Issues associated with sexually transmitted disease treatment and follow-up in the family planning clinic setting are discussed.

Expression of a leukocyte-specific antigen during ontogeny in Xenopus laevis

The monoclonal antibody CL21 recognizes a determinant present on the surface of leukocytes, but not on erythrocytes or nonhemopoietic tissue. The CL21 antigen was first expressed at 48 hr of development at 20 degrees C (stage 28) on embryonic cells cultured from lateral plate mesoderm. Based on immunofluorescence staining and flow cytometric analysis, the distribution of fluorescence intensity of larval thymocytes and splenocytes was unimodal. Distributions of dull and bright cells were detected in both adult thymocytes and splenocytes. These different subpopulations appeared during the late perimetamorphic period. Adult splenocytes were metabolically activated when cultured in the presence of mAb CL21 bound to a substrate but not in the presence of mAb CL21 in suspension. Immunoprecipitation and SDS-PAGE under nonreducing conditions revealed that a single 180-kD molecule was expressed on thymocytes. Analysis of splenocytes demonstrated the presence of two molecules having similar molecular mass that resolved to a single band under reducing conditions.

Incentives and their influence on appointment compliance in a teenage family-planning clinic

The purpose of this study was to ascertain whether or not the family-planning compliance patterns of indigent adolescents could be influenced by various types of incentives. From February 1988 through January 1989, 534 postpartum inner city teenagers, aged 12-19, who delivered at a large city-county public hospital, participated. Teens were randomly assigned to two treatment groups that either offered a coupon for milk for the infant or a gift for the teenage mother if they returned for their postpartum visit 4-6 weeks after delivery. A third group, which used no incentive for appointment keeping, acted as a control. Although overall compliance was low, a significant relationship was found between type of program incentive and compliance outcome. The program using milk coupons as an incentive had the best compliance rate. This incentive appeared to be most effective with black adolescents. Such incentive programs, although not without controversy, offer a potential way to enhance postpartum contraceptive appointment-keeping compliance in a high-risk population.

Ortho enzyme immunoassay versus McCoy cell monolayers stained by iodine or fluorescent antibody for detection of Chlamydia trachomatis

We compared a new enzyme immunoassay (Ortho Diagnostics Systems, Inc., Raritan, N.J.) (EIA) with iodine and fluorescent-antibody staining of inoculated McCoy cell monolayers for detection of Chlamydia trachomatis in our female outpatient populations. EIA was more sensitive than iodine at a statistically significant level, but there were no statistically significant differences between EIA results and those for fluorescent-antibody staining.

Agreement between visual and automated UniScept API readings

The UniScept API system was evaluated for agreement of visual versus automated readings of both its identification panels and its antimicrobial susceptibility panels. The biochemical responses of 340 oxidase-negative and oxidase-positive fermentative bacterial cultures were read both visually and automatically in the UniScept API 20E system. Automated and visual readings agreed with 99.3% of the biochemicals. Of the 45 tests that disagreed, the tests for indole and citrate were most often in disagreement. A total of 470 fermentative and nonfermentative cultures were used in the UniScept MIC system to compare visual and automated readings of susceptibility results with 17 antimicrobial agents. Agreement within +/- 1 dilution occurred with 94.1% of the enteric fermenters and with 91.7% of the other cultures. Comparison of visual and automated readings resulted in very major discrepancies in 0.95% of the readings, with the largest percentage of discrepancies associated with glucose nonfermenters (1.8%). It was felt that an automated reading is an acceptable alternative to a visual reading of the biochemicals but that 0.95% was just within the acceptable range of the 1% allowable very major discrepancies in the automated reading of susceptibilities.

Cationic liposomes (Lipofectin) mediate retroviral infection in the absence of specific receptors

We have used cationic liposomes (Lipofectin) to facilitate retrovirus infection of cells lacking the homologous viral receptor. Ecotropic murine leukemia virus and packaged retroviral vectors were shown to infect mink cells, and amphotropic packaged retroviral vectors were shown to infect hamster cells in the presence of Lipofectin but not in the presence of Polybrene. Lipofectin-mediated infection of cells lacking the homologous receptor results in a titer approximately 0.1% of the titer in cells with the homologous receptor, using the standard Polybrene protocol. The use of Lipofectin may provide a simple means to experimentally infect a wide variety of cells with viruses not normally infectious for the species, tissue, or cell type of interest.

Preventing child abuse and neglect in Texas

The rising prevalence of child abuse and neglect in Texas underscores the need to encourage innovative programs across the state. Primary prevention efforts catalyzed by the Children's Trust Fund of Texas demonstrate such projects. Specific evaluation techniques are also reviewed with some explanation of why some programs may be more effective than others.

Location of hemopoietic stem cells influences frequency of lymphoid engraftment in Xenopus embryos

The first hemopoietic stem cells to differentiate in Xenopus embryos arise from ventral blood island (VBI) mesoderm. Progeny of these stem cells contribute to larval E, macrophage, thymocyte, and B lymphocyte populations. When small pieces of mesoderm are transplanted to a central location within the VBI, the contribution of this mesoderm is predominantly to erythropoiesis and engraftment of lymphoid populations is minimal. The present experiments examined the influence of position within the VBI on the contribution of single stem cells to lymphoid populations. Pieces of diploid VBI mesoderm, containing an average of one hemopoietic stem cell, were transplanted to either a central or a peripheral location within the defined boundaries of the VBI of triploid, stage matched embryos. The number of animals with donor-derived cells in lymphoid populations was markedly increased when stem cells were grafted to a peripheral position. In three cases, stem cells contributed to lymphoid populations at the exclusion of erythroid populations. These data were consistent with the notion of either a lymphoid stem cell or restricted B and T lymphocyte precursors. These data also suggested that during embryogenesis, stochastic differentiation of hemopoietic stem cells was influenced by regional differences in the VBI microenvironment.

Location of hemopoietic stem cells influences frequency of lymphoid engraftment in Xenopus embryos

The first hemopoietic stem cells to differentiate in Xenopus embryos arise from ventral blood island (VBI) mesoderm. Progeny of these stem cells contribute to larval E, macrophage, thymocyte, and B lymphocyte populations. When small pieces of mesoderm are transplanted to a central location within the VBI, the contribution of this mesoderm is predominantly to erythropoiesis and engraftment of lymphoid populations is minimal. The present experiments examined the influence of position within the VBI on the contribution of single stem cells to lymphoid populations. Pieces of diploid VBI mesoderm, containing an average of one hemopoietic stem cell, were transplanted to either a central or a peripheral location within the defined boundaries of the VBI of triploid, stage matched embryos. The number of animals with donor-derived cells in lymphoid populations was markedly increased when stem cells were grafted to a peripheral position. In three cases, stem cells contributed to lymphoid populations at the exclusion of erythroid populations. These data were consistent with the notion of either a lymphoid stem cell or restricted B and T lymphocyte precursors. These data also suggested that during embryogenesis, stochastic differentiation of hemopoietic stem cells was influenced by regional differences in the VBI microenvironment.

A cluster of blister-associated toxic shock syndrome in male military trainees and a study of staphylococcal carriage patterns

In March-April 1985, toxic shock syndrome (TSS) developed in three male military trainees at one base secondary to infected blisters acquired while marching during basic combat training. One trainee died. Staphylococcus aureus was isolated from the blisters in all three patients, and the two strains available for testing both produced toxic shock syndrome toxin-1 (TSST-1). A culture survey identified carriage of S. aureus in 44% (145/333) of the trainees; carriage rates did not differ between the company with two ill trainees and a control company. Carriage was more frequent in the nose than foot (41% versus 9%, p less than 0.0001). White trainees were more likely to carry S. aureus than black trainees (47% versus 28%, p = 0.013), although the same proportion of strains was positive for TSST-1 in both races. The two strains obtained from the patients had similar but not identical phage typing patterns, but had identical antibiograms, and neither strain carried any plasmids. Based upon phage typing of the TSST-1 positive S. aureus strains isolated in the study, widespread carriage of the case strain(s) in other trainees was not found nor was clustering noted by barrack room. It is possible that differences in carriage rates may partially explain the low rate of TSS in blacks.

Serological classification of Xanthomonas maltophilia (Pseudomonas maltophilia) based on heat-stable O antigens

Twenty-six serotypes of Xanthomonas maltophilia were defined by using 15 antisera described by Hugh and Ryschenkow (R. Hugh and E. Ryschenkow, J. Gen. Microbiol. 26:123-132, 1961) and 11 new antisera. The antisera were prepared by immunizing rabbits with bacterial strains heated at 100 degrees C for 2 h. Twelve antisera required adsorptions with cross-reacting heterologous immunizing strains. We tested 275 clinical and environmental strains of X. maltophilia with 26 antisera by the slide agglutination technique. A total of 259 (94.2%) strains were typeable, with 137 (49.8%) strains agglutinating in three antisera.

Vaginal douching in teenagers attending a family planning clinic

This study assessed the knowledge and usage patterns of vaginal douching in sexually active teenagers attending a family planning clinic. A questionnaire was administered consecutively to 94 black, 36 Hispanic, and 12 Anglo females ranging in age from 13 to 19 years. The survey showed that vaginal douching is a common practice, with almost two thirds learning about douching from their mother. The technique is primarily used for hygienic reasons with few using it to prevent pregnancy or infection. Age of first douche correlated with age of first intercourse (p less than 0.001). Almost 23% had douched within 2 days of the clinic visit, and 56% reported douching one or more times a week.