Adult diseases in children

The classic teaching in performance and interpretation of diagnostic studies is that "children are not small adults." The purpose of this article is to show a spectrum of "adult" disease entities that can occur, but are not usually considered in the pediatric population: cricopharyngeal achalasia, Schatzki's ring, achalasia, Helicobacter pylori, pancreatic carcinoma, adenocarcinoma of the colon, nasopharyngeal carcinoma, thyroid carcinoma, malignant melanoma, hydatidiform mole, renal cell carcinoma, leiomyosarcoma of the ovary and sarcoidosis. Radiologists interpreting pediatric imaging should recognize these entities and perform an appropriate diagnostic workup.

From the Journals

THE DOCTOR-PATIENT RELATIONSHIP PREVENTING LEG ULCER RECURRENCE EVIDENCE-BASED PRACTICE IN BURN MANAGEMENT.

Compression hosiery in the management of venous leg ulcers

An update on the selection and use of compression hosiery for the treatment of venous ulcers and the prevention of recurrence

The carriage of Pasteurella haemolytica in sheep and its transfer between ewes and lambs in relation to mastitis

The possible presence of Pasteurella haemolytica in the mouth of lambs and on the skin of the teats of ewes was investigated. The organism was found in the mouth of ewes and lambs and, soon after lambing, on the teat skin of ewes. It was not isolated from the teat skin of pregnant ewes 1-14 days before lambing or from the teat skin one week after the lambs had been weaned. The transfer of P. haemolytica to the teat skin is undoubtedly mediated by the lamb. There is ample opportunity for the teat orifice to be exposed to P. haemolytica during the suckling period and it is known that only a few colony-forming units of virulent organisms are required to initiate mastitis.

Cogenital bony nasal cavity deformities

Although the most common form of nasal obstruction in neonates is soft tissue edema, congenital bony nasal deformities are being recognized as an important cause of newborn airway obstruction. In addition to the well described choanal atresia, CT imaging of the newborn in respiratory distress reveals two other forms of bony nasal cavity deformities: nasal pyriform aperture stenosis and nasal cavity stenosis. All of the three types of bony nasal cavity deformities have characteristic anatomical features, are associated with distinctive congenital anomalies, and are postulated to have differing embryological causes. Five patients with congenital bony nasal cavity deformities are presented. These cases illustrate the clinical and radiological presentation of varied types of congenital nasal cavity obstruction as well as the criteria used to guide clinical management.

Sodium, potassium-activated adenosine triphosphatase activity is impaired in the guinea pig pancreatic duct system in streptozotocin-induced diabetes

In patients with type I diabetes mellitus, clinical studies have demonstrated decreased secretion of pancreatic juice by the pancreatic excretory duct system. The cause of this decrease is unknown, but could involve changes in initial signal transduction pathways or one or more of the electrolyte transport components that subserve regulated fluid secretion. We have compared responsiveness to secretin in pancreatic ducts isolated from healthy and diabetic Hartley guinea pigs and also have compared the expression of CFTR and Na+, K(+)-ATPase in these two groups, as the activities of these two proteins are essential for secretion of pancreatic juice. The increases in cyclic AMP levels evoked by exposure to either 0.1 nM or 0.1 microM secretin were not significantly different in pancreatic ducts isolated from healthy and diabetic guinea pigs nor were levels of CFTR or Na+, K(+)-ATPase expression. By contrast, Na+, K(+)-ATPase activity in pancreatic ducts isolated from diabetic guinea pigs was decreased by 70%, suggesting a change in the enzyme's catalytic properties in the diabetic tissues. The observed decrease would be expected to seriously compromise the production of pancreatic juice.

The secreted hepatitis B precore antigen can modulate the immune response to the nucleocapsid: a mechanism for persistence

The hepatitis B precore Ag (HBeAg) is a secreted nonparticulate version of the viral nucleocapsid hepatitis B core Ag (HBcAg), and its function is unknown. A proportion of HBeAg-specific Th cells evade deletion/anergy in HBeAg-transgenic (Tg) mice and mediate anti-HBe "autoantibody" (autoAb) production after in vivo activation with the appropriate Th cell peptide. This model system was used to determine how secretory HBeAg may effect deletion of Th cells in the periphery. For this purpose, HBeAg-Tg mice were bred with Fas and Fas ligand (FasL)-defective lpr/lpr and gld/gld mutant mice. Fas-FasL interactions mediate activation-induced apoptosis in the periphery. In HBeAg-Tg/+ mice, high-titrated anti-HBe autoAb was produced that was exclusively composed of the IgG1 isotype (i.e., Th2-like profile). In contrast, HBeAg-Tg/lpr and HBeAg-Tg/gld mice produced significantly less anti-HBe autoAb, and the IgG isotype patterns were broadened to include IgG2a, IgG2b and IgG3 as well as IgG1 (i.e., mixed Th1/Th2-like profile). These results suggest that HBeAg-specific Th1 cells are preferentially depleted by Fas-FasL-mediated interactions. The effect of circulating HBeAg on HBcAg-specific Th1 cells was also examined by transferring HBe/HBcAg-specific Th cells into dual HBeAg- and HBcAg-expressing Tg recipient mice. The presence of serum HBeAg ablated the expected Th1-mediated anti-HBc Ab response and shifted it toward a Th2 phenotype. These results suggest that in the context of a hepatitis B viral infection, circulating HBeAg has the potential to preferentially deplete inflammatory HBeAg- and HBcAg-specific Th1 cells that are necessary for viral clearance, thereby promoting hepatitis B virus persistence.

Gender and research productivity in US and Canadian schools of dentistry. A preliminary investigation

The purpose of this study was to evaluate individual faculty research productivity with respect to gender among clinical faculty in 66 United States and Canadian schools of dentistry. A comprehensive survey instrument was developed to collect information on factors associated with research productivity of individual faculty. The present investigation focused on time spent per week in various work related activities (teaching, administration, research, and private practice), external grant money obtained for research, and responses to 12 variables evaluating the subject's perceptions of their research background, work environment, attitude and outcome effects from publishing, and the use of colleagues in conducting research. The 833 respondents represented a response rate of 69.4% (833/1200) from a 50% stratified random sample of faculty who (1) had full-time appointments and held at least the DMD or DDS degree or the foreign equivalent, (2) taught in a clinical department of the dental school, and (3) were not departmental chairpersons or administrators. The majority of subjects responding to the survey were male (705 males, 84.6%; 128 females, 15.4%). Respondents reported a mean of 10.3 years (males = 10.8, females = 7.5) in full-time dental education and a mean of 10.1 career publications (males = 11.6, females = 6.5; P < 0.001). Although there was no significant difference in weekly hours devoted to academic responsibilities between males and females, several factors did demonstrate significant gender differences (external grant money obtained for research purposes, P < 0.03; feeling that the departmental chair did not emphasize research, P < 0.05; feeling a lack of autonomy within their institution, P < 0.007; and feeling a lack of available colleagues for research purposes, P < 0.001). The implications of the findings are discussed concerning strategies for improving research productivity for females in academic dentistry.

Specific primer design and exonuclease III treatment for the reduction of nonspecific staining in direct in situ PCR

Although direct in situ PCR is more rapid than indirect method for the in situ identification of low copy number genes, several reports indicate serious nonspecific signals with this method. Some procedures have been reported in an effort to eliminate the nonspecific signals, but the results have not been satisfactory. Exonuclease III can progressively digest blunt or recessed 3' termini of double-stranded DNA whereas DNA with 3' overhanging end is resistant to digestion. DNA fragments amplified by PCR with primers incorporating the recognition site for Sph I generate 3' four bases extensions at both end after digestion. These fragments are expected to be resistant to exonuclease III digestion. It is also expected that nonspecifically incorporated digoxigenin would be released by treatment with exonuclease III thereby reducing background. We succeeded in digesting selectively with the samples after standard PCR by Sph I and exonuclease III treatment. However, we failed to eliminate the nonspecific signals of direct in situ PCR. Southern blotting revealed that the amount of nonspecific incorporation was so huge that exonuclease III was unable to release all of nonspecifically incorporated digoxigenin and maintain specific incorporated digoxigenin simultaneously. Direct in situ PCR is a sensitive method. However, its specificity has a significant problem.

Role of B cells in antigen presentation of the hepatitis B core

The hepatitis B virus (HBV) nucleocapsid or core antigen (HBcAg) is extremely immunogenic during infection and after immunization. For example, during many chronic infections, HBcAg is the only antigen capable of eliciting an immune response, and nanogram amounts of HBcAg elicit antibody production in mice. Recent structural analysis has revealed a number of characteristics that may help explain this potent immunogenicity. Our analysis of how the HBcAg is presented to the immune system revealed that the HBcAg binds to specific membrane Ig (mIg) antigen receptors on a high frequency of resting, murine B cells sufficiently to induce B7.1 and B7.2 costimulatory molecules. This enables HBcAg-specific B cells from unprimed mice to take up, process, and present HBcAg to naive Th cells in vivo and to T cell hybridomas in vitro approximately 10(5) times more efficiently than classical macrophage or dendritic antigen-presenting cells (APC). These results reveal a structure-function relation for the HBcAg, confirm that B cells can function as primary APC, explain the enhanced immunogenicity of HBcAg, and may have relevance for the induction and/or maintenance of chronic HBV infection.

Research-based or idiosyncratic practice in the management of leg ulcers in the community

A review of the issues surrounding the dissemination, use and implementation of research into practice with particular reference to the management of leg ulcers by community nurses

The predictive value of tympanometry in the diagnosis of middle ear effusion

Over a 12-month period 501 children (age range 11 months to 15 years) underwent surgery for a possible middle ear effusion. All had tympanometry performed within 2 h of surgery. The results of tympanometry were correlated with the surgical findings in 955 ears. A type-B tympanogram has a high sensitivity (0.91) in predicting middle ear effusion with good specificity (0.79). A type-A tympanogram has a very high specificity (0.99) in predicting a dry middle ear but low sensitivity (0.34). Both the positive (0.91) and negative (0.84) predictive values of a type-A tympanogram are high. The addition of a type-C tympanogram increases the sensitivity of predicting a dry middle ear to 0.79. The positive predictive value of a peaked (type-A or -C) tympanogram is 0.71 and should be considered strong evidence that the middle ear is dry. Tympanometry is the best clinical test for the presence or absence of a middle ear effusion, and on the basis of preoperative tympanometry alone the need for surgery should be carefully reassessed.

Research: Evaluation of an education package in leg ulcer management

An experimental study was conducted with 224 nurses in the experimental group and 40 in a control group to evaluate the implementation of an education and training package in the management of leg ulceration. A knowledge and reported practice questionnaire was completed before and after an educational intervention was received by nurses in the experimental group only. There was no difference between groups in the initial scores. Following the implementation of the education and training package, nurses in the experimental group achieved a significant increase in score from 25 to 34. There was no change in score in the control group.

Detection of K-ras point mutation by in situ PCR in cell suspensions: comparison of the indirect and direct methods

In situ PCR is a new technique for the localization of low copy number sequences. We report here a method for the in situ visualization of a point mutation in K-ras codon 12 by indirect in situ PCR. Twenty-five primers were examined to select mutant-specific primers. Harvested cell lines were fixed and suspended in PCR mixture. Forty cycles of PCR in cell suspension was performed in a thermal cycler using a hot start method. Cells were cytocentrifuged onto slides, and post-fixation was performed. The specimens on the slides were then hybridized with a digoxigenin-labeled probe, followed by color reaction. Both Calu-1 (mutated: TGT) and NCI-H460 (wild type: GGT) cells had strong hybridization signals in the nuclei with general primers. But with mutant-specific primers, only Calu-1 cells had hybridization signals. No signal was observed without primers or Taq DNA polymerase. Southern blotting of the same preparation confirmed desired amplification. We also applied direct in situ PCR, but this method failed to detect the point mutation. We conclude that our indirect in situ PCR method shows the feasibility of in situ identification of single cells carrying point mutations.

The hepatitis B virus core and e antigens elicit different Th cell subsets: antigen structure can affect Th cell phenotype

Secretion of the hepatitis B virus (HBV) e antigen (HBeAg) has been conserved throughout the evolution of hepadnaviruses. However, the function of this secreted form of the viral nucleoprotein remains enigmatic. It has been suggested that HBeAg functions as an immunomodulator. We therefore examined the possibility that the two structural forms of the viral nucleoprotein, the particulate HBV core (HBcAg) and the nonparticulate HBeAg, may preferentially elicit different T helper (Th) cell subsets. For this purpose, mice were immunized with recombinant HBcAg and HBeAg in the presence and absence of adjuvants, and the immunoglobulin G (IgG) isotype profiles of anti-HBc and anti-HBe antibodies were determined. Second, in vitro cytokine production by HBcAg- and HBeAg-primed Th cells was measured. The immunogenicity of HBcAg, in contrast to that of HBeAg, did not require the use of adjuvants. Furthermore, HBcAg elicited primarily IgG2a and IgG2b anti-HBc antibodies, with a low level of IgG3, and no IgG1 anti-HBc antibodies. In contrast, the anti-HBe antibody response was dominated by the IgG1 isotype; low levels of IgG2a or IgG2b anti-HBe antibodies and no IgG3 anti-HBe antibodies were produced. Cytokine production by HBcAg- and HBeAg-primed Th cells was consistent with the IgG isotype profiles. HBcAg-primed Th cells efficiently produced interleukin-2 (IL-2) and gamma interferon (IFN-gamma) and low levels of IL-4. Conversely, efficient IL-4 production and lesser amounts of IFN-gamma were elicited by HBeAg immunization. The results indicate that HBcAg preferentially, but not exclusively, elicits Th1-like cells and that HBeAg preferentially, but not exclusively, elicits Th0 or Th2-like cells. Because HBcAg and the HBeAg are cross-reactive in terms of Th cell recognition, these findings demonstrate that Th cells with the same specificity can develop into different Th subsets based on the structural form of the immunogen. These results may have relevance to chronic HBV infection. Circulating HBeAg may downregulate antiviral clearance mechanisms by virtue of eliciting anti-inflammatory Th2-like cytokine production. Last, the influence of antigen structure on Th cell phenotype was not absolute and could be modulated by in vivo cytokine treatment. For example, IFN-alpha treatment inhibited HBeAg-specific Th2-mediated antibody production and altered the IgG anti-HBe isotype profile toward the Th1 phenotype.

Gliotoxicity in brain reaggregate cultures caused by oxidants and excitatory amino acids can be prevented by alpha-tocopherol and MK-801

Glutamine synthetase (GS) is a key enzyme involved in glutamate compartmentalisation which may be pivotal in the course of both central free-radical mediated and excitotoxic events. The ability of the oxidants FeCl2 and H2O2 and the excitatory amino acid, N-methyl-D-aspartate (NMDA) to induce changes in astrocytic GS and glial fibrillary acidic protein (GFAP), were assessed in whole rat brain reaggregate cultures. Both FeCl2 and H2O2 reduced GS activity whereas NMDA produced a large increase in enzyme activity. GFAP was not altered significantly by either oxidant although NMDA increased the level of this protein. These effects on such astroglial markers could be reversed in vitro following exposure to a-tocopherol (FeCl2 and H2O2) and MK-801. This study therefore demonstrates that inactivation of GS can be caused by free radical insult whereas stimulation of brain GS and reactive gliosis is produced by excitatory amino acids acting at neuronal NMDA receptors. The study of these gliotoxic events in 3-dimensional reaggregate cultures suggests that this model may be used to detect neuroprotective effects of novel pharmacological agents.

Cervical thymic cysts

Cervical thymic cysts are a rare cause of neck masses in children. This case report describes a three-year-old child with a several-month history of an enlarging neck mass, who was emergently admitted due to airway obstruction. Computed tomography revealed a large cystic mass extending from the oropharynx to the level of the mediastinum. Excision of the mass with pathologic examination revealed a thymic cyst. The clinical picture, the theories regarding development of these cysts, as well as surgical options for treatment, are discussed.

Regeneration of sensory cells after laser ablation in the lateral line system: hair cell lineage and macrophage behavior revealed by time-lapse video microscopy

The regeneration of sensory hair cells in lateral line neuromasts of axolotls was investigated via nearly continuous time-lapse microscopic observation after all preexisting hair cells were killed by a laser microbeam. The laser treatments left neuromasts with one resident cell type, which was supporting cells. Over the course of 1 week, replacement hair cells arose either directly via differentiation of cells present in the epithelium from the beginning of the time-lapse period or via the development of cells produced after one or two divisions of supporting cells. All of the cell divisions that produced hair cells were asymmetrical. During the first hour after the treatment, macrophages and smaller leukocytes were attracted to the laser-treated neuromasts. The smaller leukocytes returned to control levels 48-60 hr after the treatment, whereas macrophages remained active there throughout the period of hair cell replacement. Macrophage incidence peaked 36-48 hr after the laser treatment. Macrophages phagocytosed damaged hair cells and supporting cells, as well as new cells and preexisting cells without recognizable damage. The results provide direct evidence of hair cells arising as progeny produced from the divisions of supporting cells, evidence of hair cells and supporting cells arising from the same cell division, evidence relating to the timing of hair cell differentiation, and indirect evidence pertaining to proposals that hair cells sometimes arise via conversion of cells without an intervening division. The results also suggest that macrophages may influence early stages in the process of hair cell regeneration.

Peripheral primitive neuroectodermal tumors of the head and neck

OBJECTIVE

Primitive neuroectodermal tumor is a malignant small round cell tumor of neuroectodermal origin. The occurrence of these tumors in the head and neck is rare. Our objective is to document the frequency of presentation, methods of diagnosis, and forms of treatment used to combat primitive neuroectodermal tumors in the head and neck.

DESIGN

Retrospective chart review.

RESULTS

The most common location for primitive neuroectodermal tumors in our series was the thoracopulmonary region (46%); the next most common location was the head and neck (42%). Metastatic disease was present in 31% of patients at the time of diagnosis. Cytogenic analysis was found to be helpful in confirming the diagnosis of primitive neuroectodermal tumor. Therapy for primitive neuroectodermal tumors included surgery, chemotherapy, and radiation therapy. Survival statistics were poor, with 65% of the patients alive at 2 years' follow-up.

CONCLUSIONS

Primitive neuroectodermal tumor is an aggressive malignant small round cell tumor that may present in the head and neck. Long-term survival for patients with primitive neuroectodermal tumor is still poor; however, the use of improved chemotherapeutic agents combined with aggressive surgical control of primary disease and, in some cases, radiation therapy should lead to improved long-term survival.

Human peptidylglycine alpha-amidating monooxygenase transcripts derived by alternative mRNA splicing of an unreported exon

We are characterizing the alternatively spliced human peptidylglycine alpha-amidating monooxygenase (hPAM)-encoding mRNA transcripts expressed by human cells. Reverse transcription coupled to the polymerase chain reaction (RT-PCR) has been used to identify four alternatively spliced variants that differ in the region joining the two catalytic domains. Two of the transcripts represent previously reported splice variants differentiated by the presence (hPAM-A) or absence (hPAM-B) of a 321-nucleotide (nt) linker (optional exon A) which in the rat produce functionally distinct enzymes. Different mRNAs represent two splice variants, hPAM-C and hPAM-D, that show the presence of an exon unreported for PAM in any other species. This new exon, designated exon C, is 54 nt in length, encodes an 18-amino-acid (aa) peptide containing a conserved dibasic aa endoproteolytic processing motif, and is located 3' of exon A in human genomic DNA. We propose that cell-specific regulation of mRNA splicing would provide a mechanism for control of prohormone activation by these variants of the PAM enzyme.

Interleukin 12 suppresses autoantibody production by reversing helper T-cell phenotype in hepatitis B e antigen transgenic mice

Helper T (Th) cells are classified as Th1 or Th2 cells by virtue of cytokine secretion and function as mediators of cellular or humoral immunity, respectively. Cytokines also regulate the differentiation of Th cells. For example, interleukin (IL)-12 promotes Th1 and suppresses Th2 cell development, suggesting that IL-12 may be useful therapeutically in Th2-mediated autoimmune and allergic disorders. Therefore, the effect of systemic IL-12 treatment on in vivo autoantibody synthesis in hepatitis B e antigen (HBeAg)-expressing transgenic mice, which is dependent on self-reactive Th2 cells, was examined. Low-dose IL-12 significantly inhibited autoantibody production by shifting the Th2-mediated response toward Th1 predominance. Additionally, previous studies suggest that a predominance of HBeAg-specific Th2-type cells may contribute to chronicity in hepatitis B virus infection. Therefore, IL-12 may also prove beneficial in modulating the HBeAg-specific Th response to favor viral clearance in chronic hepatitis B virus infection.

Characterization of self-reactive T cells that evade tolerance in hepatitis B e antigen transgenic mice

Previous studies of hepatitis B e antigen (HBeAg)-expressing transgenic (Tg31e) mice have indicated that the degree of T cell tolerance was epitope specific. For example, T cells specific for residues 120-131 of HBeAg are profoundly tolerant, whereas a proportion of T cells specific for residues 129-140 escape tolerance induction in B10. S x B10-Tg31e mice. To understand the basis for differential tolerance towards two T cell sites on the same self antigen, we characterized T cell recognition of HBeAg by primary T cells and T cell hybridomas derived from HBeAg-Tg and non-Tg mice. The self-reactive T cells surviving in B10-Tg31e mice exhibited a unique fine specificity, albeit still focussed on HBeAg residues 129-140, which could be distinguished from the HBeAg-specific T cell repertoire in non-Tg B10 mice. Further, self-reactive T cells were comprised predominantly of Th2-type cells that preferentially evaded tolerance induction as compared to their Th1 counterparts. Because HBeAg may act as a tolerogen during the vertical transmission of chronic hepatitis B virus (HBV) infection, these results suggest that a predominance of HBeAg-specific Th2 cells expressing a limited repertoire may influence the initiation or the maintenance of the HBV chronic carrier state.

Preferential recognition of hepatitis B nucleocapsid antigens by Th1 or Th2 cells is epitope and major histocompatibility complex dependent

Regulatory T-helper (Th) cells have been categorized into two functional subsets, Th1 and Th2 cells, which produce distinct lymphokines. In general, Th1 cells mediate cellular immune responses and Th2 cells mediate humoral immunity. Recent serological studies suggest that the Th1-Th2 balance may be relevant in acute and chronic hepatitis B virus (HBV) infections. The purpose of this study was to determine the potential of the nucleocapsid antigens (Ags) (hepatitis B core and e Ags [HBc/eAg]) of HBV to preferentially elicit either a Th1 or a Th2 dominant response. For this purpose, H-2 congenic B10.S and B10 mice were immunized with HBc/eAg, and Ag-specific T-cell proliferative responses, T-cell helper function, and T-cell cytokine production were analyzed. The results indicated that B10.S mice preferentially develop a Th1-like response whereas B10 mice preferentially develop a Th2-like response after immunization with HBc/eAg. Furthermore, the preferential Th1 and Th2 response patterns were reproduced when 12-residue peptides representing the dominant HBc/eAg-specific T-cell sites for B10.S (peptide 120-131) and B10 (peptide 129-140) mice were used as immunogens. Therefore, the combination of the T-cell site recognized and the major histocompatibility complex restricting element can in large part determine the Th phenotype of the HBc/eAg-specific T-cell response. Other factors that influenced Th phenotype were the presence of exogenous cytokines, Ag structure, and tissue distribution.

Mathematical modelling of the growth, survival and death of Yersinia enterocolitica

This paper discusses the development of a novel mathematical equation capable of handling the growth, survival and death of microorganisms. The equation was used in combination with second-order polynomials to fit a response surface to data representing the growth, survival and death of Yersinia enterocolitica as affected by temperature (0-30 degrees C), sodium chloride (0-10.5% w/v), pH (3.5-7.0) and undissociated lactic acid (0-9.63 g/l). The resulting predictive model showed a good correlation over the entire range of the experimental data. Predictions from the model have been compared with independent data from both published literature and inoculated food studies. Analysis of the results showed a good correlation, particularly for data from milk and meat products.

Modelling the growth, survival and death of microorganisms in foods: the UK food micromodel approach

Techniques for the development of mathematical models in the area of predictive microbiology have greatly improved recently, allowing better and more accurate descriptions of microbial responses to particular environmental conditions, thus enabling predictions of those responses to be made with greater confidence. Recognising the potential value of applying these techniques in the food industry, the Ministry of Agriculture, Fisheries and Food (MAFF) initiated a nationally coordinated five-year programme of research into the growth and survival of microorganisms in foods, with the aim of developing a computerised Predictive Microbiology Database in the UK. This initiative has resulted in the systematic generation of data, through protocols which ensure consistency of methodology, so that data in the database are truly comparable and compatible, and lead to reliable predictive models. The approaches taken by scientists involved in this programme are described and the various stages in the development of mathematical models summarized. It is hoped that this initiative and others being developed in the USA, Australia, Canada and other countries, will encourage a more integrated approach to food safety which will influence all stages of food production and, eventually, result in the development of an International Predictive Microbiology Database.

Clara cell 10 kDa protein mRNA in normal and atypical regions of human respiratory epithelium

We used RNA-RNA in situ hybridization to study expression of the human CC10 gene in morphologically normal and atypical areas of 32 non-neoplastic lung specimens resected from 26 non-small cell lung cancer patients. We scored strong, moderate or weak levels of CC10 mRNA expression in 3 distinct lung compartments. In morphologically normal lungs, strong and moderate levels of CC10 mRNA were observed in bronchioli and bronchi, respectively, but the expression was rarely observed in the alveolar region. Distinct alterations in CC10 mRNA expression were noted in specific histologic abnormalities within bronchi and the alveolar region. CC10 hybridization signal decreased markedly in bronchi containing diffuse goblet cell hyperplasia or squamous metaplasia, while CC10 mRNA expression remained unchanged in bronchi with basal cell hyperplasia or focal goblet cell hyperplasia. Bronchiolar CC10 mRNA levels remained unchanged in sections containing abnormalities elsewhere. Interestingly, in alveoli with bronchiolization of the alveoli, high levels of CC10 mRNA were observed. These regions also contained strongly stained keratin 14-positive cells, which may indicate a concurrent metaplastic process. In lungs with morphologic atypias, no correlation was found between abnormalities detected in bronchi and alveoli from the same lung. A comparison of mRNA expression and clinicopathologic features demonstrated that the amount of histologic abnormalities increased with smoking history (pack years); however, no correlation between CC10 mRNA expression and sex, age or smoking history was found.

Soluble CTLA-4 can suppress autoantibody production and elicit long term unresponsiveness in a novel transgenic model

Activation of Ag-specific T cells often requires costimulatory signals in addition to the primary signal mediated through the TCR. The CD28-B7 interaction provides one important costimulatory signal. Previous studies have shown that a soluble CD28 homologue, CTLA4lg, binds B7 with high affinity and can inhibit CD28-B7-mediated costimulation in vitro and in vivo. In this study we examined the ability of soluble human CTLA4lg to inhibit autoantibody production in vivo. For this purpose we used a novel transgenic (Tg) model of autoantibody production. Hepatitis B eAg-expressing Tg mice can be induced to produce autoantibody to the circulating autoantigen (HBeAg) by the injection of a T cell recognition site that fails to elicit T cell tolerance in these mice. Autoimmunity in this model is quantitative because serum autoantibody and autoantigen concentration are inversely correlated and easily measurable by ELISA. In this system a single regimen of CTLA4lg treatment significantly suppressed primary autoantibody production and variably led to long term unresponsiveness. Furthermore, in vivo treatment with CTLA4lg inhibited both T cell activation and T cell-B cell interactions.

Soluble CTLA-4 can suppress autoantibody production and elicit long term unresponsiveness in a novel transgenic model

Activation of Ag-specific T cells often requires costimulatory signals in addition to the primary signal mediated through the TCR. The CD28-B7 interaction provides one important costimulatory signal. Previous studies have shown that a soluble CD28 homologue, CTLA4lg, binds B7 with high affinity and can inhibit CD28-B7-mediated costimulation in vitro and in vivo. In this study we examined the ability of soluble human CTLA4lg to inhibit autoantibody production in vivo. For this purpose we used a novel transgenic (Tg) model of autoantibody production. Hepatitis B eAg-expressing Tg mice can be induced to produce autoantibody to the circulating autoantigen (HBeAg) by the injection of a T cell recognition site that fails to elicit T cell tolerance in these mice. Autoimmunity in this model is quantitative because serum autoantibody and autoantigen concentration are inversely correlated and easily measurable by ELISA. In this system a single regimen of CTLA4lg treatment significantly suppressed primary autoantibody production and variably led to long term unresponsiveness. Furthermore, in vivo treatment with CTLA4lg inhibited both T cell activation and T cell-B cell interactions.

Dental-care experiences of people living with HIV/AIDS in Aotearoa New Zealand

Previous surveys of people living with HIV/AIDS suggest that such persons may have difficulty in securing dental care and that some dentists would prefer to refer such individuals. This study aimed to assess the experiences of people living with HIV/AIDS in Aotearoa New Zealand in obtaining and undergoing dental treatment. Survey forms were distributed through organisations working with people with HIV/AIDS. Fifty-seven questionnaires were analysed. The majority of respondents were gay white males. Seventy-five percent of participants felt that dental care was important, or very important, and 37 percent had increased the frequency of visits to the dentist since being diagnosed as HIV-positive. Forty-two (74 percent) participants had disclosed their HIV status to their dentists. Of this group, the majority had experienced either supportive or sympathetic reactions. Of those who concealed their status, 31 percent feared rejection by the dental practitioner, and 31 percent felt the dentist was taking adequate precautions and that there was no need to volunteer information on HIV status. Only three people reported denial of treatment on the grounds of their HIV status. An additional two people were immediately referred on by their practitioner after disclosure. Almost half the participants had changed dentists after they were diagnosed as HIV-positive. The main reasons stated included cost of treatment, fear of breach of confidentiality, or shifting to a new centre. Even though 33 percent received dental care in a hospital environment, 63 percent suffered systemic manifestations of HIV-infection, and 51 percent had oral manifestations.(ABSTRACT TRUNCATED AT 250 WORDS)

Incongruence of existing practice management curricula content and actual medical practice need

BACKGROUND AND OBJECTIVES

Practice management is an important, but often overlooked, element of medical training, especially for physicians in primary care. The objective of this study was to evaluate our program's practice management curriculum to determine if it meets the needs of its graduates.

METHODS

A questionnaire, developed and sent to 1986-1991 graduates of the residency program (n = 76), determined their perceptions of how well the practice management curriculum prepared them to operate a practice. Fifty (65.8%) usable surveys were returned.

RESULTS

The respondents perceived deficits in areas of preparing for office management, starting and building a practice, using professional services (especially in the areas of financial decisions and use of professionals), and reimbursement procedures.

CONCLUSIONS

Physicians need an understanding of business fundamentals such as economics, organization management, contract evaluation, negotiation and mediation skills, methods of allocation of limited resources, information science, and consumerism. This article offers a process through which other family practice residency programs can begin evaluating and restructuring their practice management curricula to meet these needs.

Some properties of coagulase-negative staphylococci isolated from cases of ovine mastitis

Of 41 coagulase-negative staphylococcal isolates from cases of ovine mastitis, 80% were speciated by the 'API-Staph SYSTEM' and 90% by a combination of biochemical tests. Staphylococcus simulans and Staph. xylosus were the two most prevalent species.

Extrathymic expression of the intracellular hepatitis B core antigen results in T cell tolerance in transgenic mice

We previously developed a transgenic (Tg) murine lineage (B10.S-Tg31e), which secretes the hepatitis B e Ag (HBeAg) into the serum at a concentration of 10 ng/ml. This serum concentration was sufficient to render B10.S-Tg31e mice functionally tolerant at the T cell but not B cell level. To determine the tolerogenic potential of an intracellular form of this Ag, namely the hepatitis B core Ag (HBcAg), expressed outside the thymus, the B10.S-Tg10c lineage was developed. In B10.S-Tg10c mice the HBcAg is expressed as an intracellular "self"-Ag predominantly in the liver, and cannot be detected in the serum, the thymus or in nonthymic lymphoid tissue. Despite the liver-specific and intracellular location of this transgenic self-protein, B10-STg10c mice demonstrate a significant degree of HBcAg-specific T cell tolerance at the level of T cell proliferation. Similarly, in vivo anti-HBc antibody production after HBcAg immunization is significantly reduced as compared with non-Tg littermate controls. No spontaneous anti-HBc antibody is produced in B10.S-Tg10c mice, however, adoptive transfer of HBcAg-specific T cells from non-Tg B10.S mice elicits anti-HBc specific "autoantibody" production. Interestingly, antibodies with specificity for the HBeAg as well as the HBcAg are produced. Antibody production in B10.S-Tg10c mice adoptively transferred with T cells indicates that sufficient native HBcAg can gain access to the extracellular compartment to engage HBcAg-specific B cells that are clearly not tolerant in this model. No liver injury was observed as a consequence of HBcAg expression, even in B10.S-Tg10c mice adoptively transferred with HBcAg-specific T cells. Unless HBcAg is unique in this regard, these results suggest that organ-specific, intracellular self-Ag may be released during normal cell turnover in sufficient concentrations to elicit systemic T cell tolerance. B10.S-Tg10c mice also serve as an immunologic model system for chronic infection with the HBeAg-negative mutant of the hepatitis B virus.

Extrathymic expression of the intracellular hepatitis B core antigen results in T cell tolerance in transgenic mice

We previously developed a transgenic (Tg) murine lineage (B10.S-Tg31e), which secretes the hepatitis B e Ag (HBeAg) into the serum at a concentration of 10 ng/ml. This serum concentration was sufficient to render B10.S-Tg31e mice functionally tolerant at the T cell but not B cell level. To determine the tolerogenic potential of an intracellular form of this Ag, namely the hepatitis B core Ag (HBcAg), expressed outside the thymus, the B10.S-Tg10c lineage was developed. In B10.S-Tg10c mice the HBcAg is expressed as an intracellular "self"-Ag predominantly in the liver, and cannot be detected in the serum, the thymus or in nonthymic lymphoid tissue. Despite the liver-specific and intracellular location of this transgenic self-protein, B10-STg10c mice demonstrate a significant degree of HBcAg-specific T cell tolerance at the level of T cell proliferation. Similarly, in vivo anti-HBc antibody production after HBcAg immunization is significantly reduced as compared with non-Tg littermate controls. No spontaneous anti-HBc antibody is produced in B10.S-Tg10c mice, however, adoptive transfer of HBcAg-specific T cells from non-Tg B10.S mice elicits anti-HBc specific "autoantibody" production. Interestingly, antibodies with specificity for the HBeAg as well as the HBcAg are produced. Antibody production in B10.S-Tg10c mice adoptively transferred with T cells indicates that sufficient native HBcAg can gain access to the extracellular compartment to engage HBcAg-specific B cells that are clearly not tolerant in this model. No liver injury was observed as a consequence of HBcAg expression, even in B10.S-Tg10c mice adoptively transferred with HBcAg-specific T cells. Unless HBcAg is unique in this regard, these results suggest that organ-specific, intracellular self-Ag may be released during normal cell turnover in sufficient concentrations to elicit systemic T cell tolerance. B10.S-Tg10c mice also serve as an immunologic model system for chronic infection with the HBeAg-negative mutant of the hepatitis B virus.

Attitudinal factors associated with individual faculty research productivity in academic dentistry

The purpose of this study was to examine attitudinal factors associated with increased research productivity of individual clinical faculty in 66 United States and Canadian schools of dentistry. Thirteen variables, evaluating the subjects' perceptions of their research background, work environment, attitude and outcome effects from publishing, and the use of colleagues in conducting research, were evaluated. The 833 respondents represented a response rate of 64.9% (833/1200) from a 50% stratified random sample of faculty who (1) had full-time appointments and held at least the D.M.D. or D.D.S. degree or the foreign equivalent, (2) taught in a clinical department of the dental school, and (3) were not departmental chairpersons or administrators (assistant dean, associate dean, or dean). Respondents reported a mean of 10.3 yr. (range = 1 to 45, SD = 7.3) in full-time dental education (career age) and a mean of 10.1 career publications (range = 0 to 110, SD = 13.8). Analysis of variance for mean number of career publications, by increasing agreement in response to each attitudinal variable, yielded a significant positive association for each of the 13 attitudinal variables. Implications of the findings were discussed with respect to strategies for improving research productivity of individual faculty.

Replacement of lateral line sensory organs during tail regeneration in salamanders: identification of progenitor cells and analysis of leukocyte activity

It has been proposed that supporting cells may be the progenitors of regenerated hair cells that contribute to recovery of hearing in birds, but regeneration is difficult to visualize in the ear, because it occurs deep in the skull. Hair cells and supporting cells that are comparable to those in the ear are present in lateral line neuromasts, and in axolotl salamanders these cells are accessible to microscopic observation in vivo. After amputation of a segment of the tail that contains neuromasts, cells from the posteriormost neuromast on the tail stump divide rapidly and form a migratory regenerative placode. The cells of the regenerative placode represent a lineage that eventually produces both hair cells and supporting cells in replacement neuromasts. We sought to identify the progenitors of the regenerative placode by using differential interference contrast microscopy combined with time-lapse video recording in living axolotl salamanders. In response to amputation, the mantle-type supporting cells at the posteroventral edge of the neuromast that is nearest to the wound increased their frequency of cell division, and gave rise to the first cells of the placode. The increase in mitotic activity of mantle-type supporting cells was accompanied by an unexplained decrease in the frequency of divisions in the same neuromast's population of internal supporting cells. The time-lapse records suggested that the changes in the mitotic activity of supporting cells might have been linked to the presence of phagocytic leukocytes in the vicinity of the neuromast that was nearest to the wound. Leukocytes were evenly distributed around control neuromasts, but during regeneration leukocyte activity increased significantly in the vicinity of the posterior half of the posteriormost neuromast. The redistribution of leukocytes occurred early in the regenerative response, but a causal role for the leukocytes has not been conclusively established. It is possible that the leukocytes could contribute to the formation of the regenerative placode at that location by breaking down the glycocalyx that ensheaths the outermost cells of the neuromast, or through the secretion of mitogenic growth factors.

The effect of a student summer assistantship program in family medicine on specialty selection

BACKGROUND AND OBJECTIVES

Stimulating medical students' interest in family practice is a goal of family medicine education. Summer assistantship programs have been instituted to help address this issue.

METHODS

This study evaluated the results of residency program selection for participants in a family medicine summer assistantship program during a five-year period. Students who applied for the assistantship but were not accepted were used as a comparison group to measure student interest in family medicine. Additional comparisons were made with students who neither applied to nor participated in the program. All students were followed until residency program selection had occurred, after which each participant in the assistantship program completed a questionnaire regarding the effect of the assistantship on residency selection.

RESULTS

The difference in rate of family practice residency selection between the participants (n = 31) and those who applied but were not accepted (n = 57) was not significant (X2 = .3, df = 1, P = NS). However, the difference in family practice residency selection between the participants and those not applying (n = 403) was significant (X2 = 6.46, df = 1, P < .05). Participants selecting a family practice residency program were more likely to feel that the summer assistantship experience was their basis for selecting their residencies (mean 7.6 versus 4.7, P < .05 for t test).

CONCLUSION

The difference in the rate of entry into family practice residency programs between the assistantship participants and those who applied but were not accepted was not significant.

Structure of hepatitis B virus core and e-antigen. A single precore amino acid prevents nucleocapsid assembly

The hepatitis B virus core gene codes for two polypeptides: the core protein, which assembles to form particles (HBcAg), and the secreted precore protein (HBeAg). Expression vectors directing the synthesis in Escherichia coli of a recombinant HBeAg corresponding in sequence to serum-derived HBeAg encompassing the 10 precore amino acids remaining after cleavage of the precursor and residues 1-149 of HBcAg (PC-HBeAg) were constructed. Recombinant PC-HBeAg, HBcAg, and C-terminally truncated HBcAg were isolated from E. coli and analyzed by sucrose velocity sedimentation, electron microscopy, anti-HBc/e specific monoclonal antibody analysis, and for immunogenicity. HBcAg and truncated HBcAg formed 27-nm particles and displayed HBc antigenicity. In contrast, PC-HBeAg was nonparticulate and did not band in sucrose gradients. PC-HBeAg was recognized efficiently by HBeAg-specific antibodies and displayed little HBc antigenicity. Immunogenicity studies including T and B cell recognition confirmed that PC-HBeAg demonstrates HBe antigenicity. The presence of the 10 precore amino acids therefore prevented particle formation. To analyze which precore amino acids might be responsible for the prevention of particle formation a cysteine to glutamine substitution at amino acid position -7 was introduced into PC-HBeAg (-7C-->Q)PC-HBeAg. This single amino acid change at position -7 restored particle formation and HBc antigenicity. The evolutionarily conserved cysteine at position -7 thus appears responsible for the prevention of particle assembly in the HBeAg biosynthesis pathway.

Asymmetric radiographic findings in the pediatric chest: approach to early diagnosis

Several conditions in children produce a mass effect within one hemithorax, which may be life threatening. The different radiographic appearances of these conditions provide a basis on which they can be classified. The three major categories include a large cystic hemithorax, a large lucent hemithorax, and a large opaque hemithorax. Some disorders may be seen within more than one major group. Within the large cystic hemithorax group, congenital cystic adenomatoid malformation and congenital diaphragmatic hernia may be life-threatening conditions that require emergency surgery. The large lucent hemithorax is usually caused by pneumothorax, partial bronchial occlusion, or compensatory hyperinflation of the unobstructed lung. The majority of cases within the large opaque hemithorax group involve pleural fluid collections. Because many conditions that cause a mass effect require intervention or surgery, accurate interpretation of the plain chest radiograph is essential for an early diagnosis. Classification of radiographic features into these three groups often allows accurate diagnosis without additional studies.

Transoral surgical management of lesions of the base of the tongue

Lesions of the base of the tongue are rare in the pediatric population. However, when present these lesions may lead to airway obstruction and feeding difficulties. Two patients with lesions of the base of the tongue are described to demonstrate the diagnosis and management of this difficult clinical problem. The use of a transoral median glossotomy for total excision of these lesions is advised in this article. This approach affords excellent surgical exposure, early return to a normal diet, and lack of facial scars.

Ovarian masses revisited: radiologic and pathologic correlation

Diagnosis of ovarian masses can be difficult because many pathologic conditions can affect the ovary and have similar clinical and radiologic manifestations. Knowledge of pathologic, age-specific characteristics can help refine the differential diagnosis. Ovarian masses are nonneoplastic (ovarian functional cysts, polycystic ovary disease, and ovarian torsion) or neoplastic (surface epithelial, sex cord-stromal, germ cell, and metastatic tumors). Functional cysts, if complicated by hemorrhage, can have a confusing ultrasonographic (US) appearance. Polycystic disease and torsion are easily diagnosed with US. Benign and malignant forms of serous and mucinous surface epithelial tumors can usually be differentiated with US. Imaging features of surface epithelial tumors of low malignant potential are nonspecific, resembling those of benign serous and mucinous tumors. Mature (benign) teratomas are usually cystic, with components of fat, soft tissue, and calcium, and are sonographically distinct from immature (malignant) teratomas, which are mostly solid. Sex cord-stromal tumors occur more often in menopausal or postmenopausal women and are typically solid. Metastatic disease is less common than other ovarian tumors; however, its radiologic appearance may resemble those of other masses.

Severity of premenstrual symptoms in relation to medical/psychiatric problems and life experiences

The Premenstrual Experience Assessment, a comprehensive questionnaire, was completed by 878 women who were currently having menstrual cycles. Their severity of premenstrual symptoms was studied in relation to demographic variables, gynecological problems, use of medications, psychiatric experience, life stressors, and duration of severity. 14 significant relationships were found. The findings are discussed both in terms of research and clinical practice.

The effect of inoculation of Pasteurella haemolytica into the lactating mammary gland of mice, rats, rabbits, sows and cows

An isolate of Pasteurella haemolytica (A9), which consistently produced severe mastitis in ewes, was inoculated into the lactating mammary glands of a variety of species. Mastitis did not develop after the inoculation of log-phase bacteria into the mammary gland of lactating mice, rats, rabbits or sows but did so in the mammary gland of two cows. Another A9 isolate from a ewe with mastitis and an A1 isolate from a bovine pneumonic lung also induced mastitis in cows. Thus, in this study, P. haemolytica produced mastitis only in ruminant animals.

Jaundice

Jaundice is a disorder of bilirubin metabolism and has many causes. History and physical examination help establish the diagnosis in 70 to 80 percent of patients. Elevation of alkaline phosphatase and gamma-glutamyl transpeptidase suggests cholestasis, either intrahepatic (e.g., medication reactions) or extrahepatic (e.g., choledocholithiasis), whereas markedly elevated serum aminotransferases are indicative of hepatocellular damage from infection, toxins or ischemia. Ultrasound examination is a useful initial procedure when extrahepatic obstruction is suspected. Endoscopic retrograde cholangiopancreatography and computed tomography may be better used to diagnose obstruction at the level of the pancreas or distal common bile duct. The treatment is based on the etiology of jaundice and includes removal of offending medications or toxins, therapy for underlying liver disease or surgery for extrahepatic obstruction.

The effect of the intra-mammary inoculation of lactating ewes with Pasteurella haemolytica isolates from different sources

Lactating Welsh Mountain ewes were inoculated, 3 weeks after lambing, with between 1000 and 10,000 colony forming units of a number of isolates of Pasteurella haemolytica. Isolates from severe, acute mastitis in a ewe, from ovine and bovine pneumonic lesions and from the nasal cavity of healthy lambs, all gave rise to severe, acute mastitis that was clinically indistinguishable from that seen naturally. Two isolates from the milk of ewes with subclinical mastitis did not cause clinical disease after inoculation and, in most ewes, were immediately eliminated. These results suggest that a variety of strains of P. haemolytica are capable of causing severe mastitis in sheep, regardless of their origin, and that there are strains of lower pathogenicity for the mammary gland which are not capable of causing clinical mastitis.