Spinal meningeal melanocytoma: a case report and review of the literature

We present a case of spinal meningeal melanocytoma involving the C5 nerve root with spinal cord compression which resembled a neurinoma clinically as well as radiologically. The clinical, radiological and pathological features of this and 11 other cases reported in the literature are reviewed. The significance of correct diagnosis and aggressive surgical management of this benign neoplasm is emphasized.

Spinal cord compression caused by ossification of the transverse ligament of the atlas

Although ossification of the posterior longitudinal ligament and ligamentum flavum are well known, ossification of the transverse ligament of the atlas is extremely rare. We present the case of a 79-year-old man who developed a gradually progressive spastic quadriparesis caused by upper cervical canal stenosis due to ossification of the transverse ligament of the atlas together with ligamentum flavum hypertrophy.

Effect of clinically relevant culture conditions on antimicrobial susceptibility of Chlamydia trachomatis

Infection of polarized human endometrial-gland epithelial cells obtained at hysterectomy with Chlamydia trachomatis serovar E may provide a relevant in vitro model for studies of pharmacokinetics in genital chlamydial infections. The minimal bactericidal concentration of azithromycin against C. trachomatis was lower in this model than in studies with nonpolarized cells (0.125 and 0.5 mg/L, respectively). Polarized cells also internalized more azithromycin over 24 hours. The results indicate that the eradication of chlamydial infections may be difficult to prove by antigen detection methods: the persistence of chlamydial envelope material within the intracellular vacuoles of azithromycin-treated cells may lead to a false-positive diagnosis of persisting chlamydial infection.

Minimally invasive neurosurgery using CRW-3 stereotaxy

The Cosman-Roberts-Wells (CRW-3) scanner independent stereotactic system is a recent arc-radius design developed from the Brown-Roberts-Wells system. The results of 74 supratentorial non-basal tumor suspect cases treated with this second generation computed tomography (CT) guided stereotactic apparatus are presented. Using a simple stereotactic target classification coupled with biopsy, trephine or mini-craniotomy, it has been possible to biopsy, excise and develop new strategies using microneurosurgical techniques with extremely low morbidity.

Chlamydia trachomatis does not bind to alpha beta 1 integrins to colonize a human endometrial epithelial cell line cultured in vitro

Chlamydia trachomatis is the leading cause of bacterially acquired sexually transmitted diseases in the United States and Europe. As an obligate intracellular pathogen, this bacterium must invade epithelial cells in order to survive and grow. Thus, multiple strategies probably exist for initial binding of chlamydiae to their target cells. Since a variety of bacteria have exploited integrins to colonize tissues, and a precedent existed for the involvement of extracellular matrix components in chlamydial attachment, this study first analyzed, by flow cytometry, integrins expressed by the human endometrial epithelial cell line HEC-1B. The genital cells were then exposed to monoclonal antibodies directed against those integrins and assayed for chlamydial attachment and inclusion development. Monoclonal antibodies bound to the alpha and/or beta 1 subunit of classic integrin receptors displayed by HEC-1B cells were not able to prevent colonization and infection of the epithelial cells by a genital isolate of C. trachomatis.

Expression of recombinant DNA introduced into Chlamydia trachomatis by electroporation

Electroporation was used to introduce DNA into the elementary bodies of the obligate parasitic bacterium Chlamydia trachomatis. The source of DNA for these experiments was the chimeric plasmid pPBW100, which was constructed from the well-characterized 7.5-kb plasmid of C. trachomatis and the Escherichia coli plasmid pBGS9. To select directly for C. trachomatis carrying pPBW100, an in-frame gene fusion between the chlamydial promoter P7248 and a promoterless chloramphenicol acetyltransferase (cat) cassette was incorporated into the plasmid. After infection of McCoy cells with electroporated elementary bodies containing pPBW100, the following were observed: (i) the plasmid DNA was detected inside the chloramphenicol-resistant chlamydial inclusions by in situ and Southern hybridization analyses; (ii) both physical and biochemical evidence showed that chloramphenicol acetyltransferase was synthesized by the electroporated C. trachomatis; (iii) expression of P7248::cat was developmentally regulated and occurred during the early stages of chlamydial reticulate body development; and (iv) although the expression from P7248::cat was mainly transient, there were rare instances where chloramphenicol-resistant C. trachomatis were observed after four passages.

The report to Congress on the appropriate federal role in assuring access by medical students, residents, and practicing physicians to adequate training in nutrition

The Congress has had a long-time concern about the adequacy of nutrition education provided medical students and physicians during their training. Attempts over three decades to address this deficiency have been largely ineffective. Yet, recent changes in the delivery of health care from inpatient to outpatient services require physicians be competent in both applied nutrition and patient counseling. The importance of patient counseling is underscored by the surveys of the National Center for Health Statistics which reveal that overweight for the U.S. population has increased between the early 60s and the late 80s. These findings suggest that the Healthy People 2000 objective of reducing the prevalence of overweight may not be met. Congress evidenced its concern about the nutrition education in the medical curriculum in Section 302 of the National Nutrition Monitoring and Related Research Act of 1990 that required a report on the subject from the Secretary of Health and Human Services. The Division of Medicine in the Health Resources and Services Administration, an agency of the Public Health Service, responded by compiling the report. The report to Congress focuses on two issues--why it has been so difficult to increase the nutrition content of medical school curriculums and, if the Federal Government intervenes, what strategies might be effective.

Molecular characterization and outer membrane association of a Chlamydia trachomatis protein related to the hsp70 family of proteins

One route by which Chlamydia trachomatis is internalized into host endometrial epithelial cells is receptor-mediated endocytosis. Although this implies an adhesin-receptor interaction exists, specific chlamydial surface molecules have not been identified. We are investigating potential adhesin molecules using an in vitro functional assay to select for chlamydial recombinant Escherichia coli expressing an adherent phenotype. We have previously shown that E. coli JM109(pPBW58) attaches to epithelial cells by a specific process paralleling C. trachomatis and expresses at least three plasmid-encoded proteins (18, 28, and 82 kDa; Schmiel, D. H., Knight, S. T., Raulston, J. E., Choong, J., Davis, C. H., and Wyrick, P. B. (1991) Infect. Immun. 59, 4001-4012). In this report, we demonstrate that (i) the 82-kDa protein is associated with the outer membrane of both E. coli JM109-(pPBW58) and C. trachomatis serovar E elementary bodies; (ii) the plasmid-encoded protein is identical to the native chlamydial protein by mass, charge, antigenicity, and partial proteolytic peptide profiles; (iii) a highly homologous protein is present in C. trachomatis biovariant lymphogranuloma venereum; (iv) the 82-kDa protein is not covalently linked by disulfide bonds to other protein species in either E. coli JM109(pPBW58) or C. trachomatis; (v) sequence analysis of the open reading frame indicates this protein is a relative of the heat shock 70 family of proteins; and (vi) the inferred amino acid sequence contains a contiguous 73-amino acid region having 51% identity with the extracellular sperm receptor binding domain in Strongylocentrosus purpuratus (Foltz, K. R., Partin, J. S., and Lennarz, W. J. (1993) Science 259, 1421-1425). The potential involvement of an hsp70 protein in attachment may provide new insight on adherence mechanisms by obligate intracellular pathogens.

In-vitro activity of azithromycin on Chlamydia trachomatis infected, polarized human endometrial epithelial cells

The in-vitro activity of azithromycin on Chlamydia trachomatis infected human endometrial epithelial cells, both primary and transformed cells growing in a polarized and non-polarized orientation, was analyzed. Addition of azithromycin two hours after adsorption inoculation with continued exposure until 72 h gave an MIC90 and MBC90 of 0.063 and 0.5 mg/L, respectively. In addition, the MBC results were more pronounced in infected cells growing in a polarized orientation. Numerous small fluorescent 'spots' (presumed small abnormal inclusions) were visible in the infected cells exposed to MIC concentrations of azithromycin. Immuno-transmission electron microscopy examination revealed intracellular inclusions filled with chlamydial envelope ghosts. Since standard diagnostic antigen detection methods use anti-envelope antibodies, the aberrant envelope-filled inclusions might be interpreted as viable inclusions by fluorescent microscopy and result in high false positive readings. To simulate treatment of an infected patient, azithromycin was added at 18 h to infected cells containing many reticulate bodies and exposure continued for 54 h after which killing of chlamydiae was seen. The use of polarized human cells may offer a more relevant in-vitro model system for examining the efficacy of antimicrobial action.

Eukaryotic cells grown on microcarrier beads offer a cost-efficient way to propagate Chlamydia trachomatis

The use of microcarrier cell culture as a method for the in vitro propagation of the obligate intracellular bacterial parasite, Chlamydia trachomatis, is described. The microcarrier beads proved to be a more cost-effective means to propagate C. trachomatis than traditional tissue culture flasks or roller bottles without sacrificing yields or infectivity. In addition, microcarrier cell culture was found to be a much simpler technique to study the intracellular development of these bacteria.

Location of the origin of replication for the 7.5-kb Chlamydia trachomatis plasmid

The hypothetical origin of replication for the 7.5-kb plasmid common to Chlamydia trachomatis is believed to be in a region of the plasmid that contains four 22-bp tandem repeats preceded by an A-T-rich region. To test this hypothesis, replication of plasmid DNA in metabolically active reticulate bodies of the Lymphogranuloma venereum biovar of C. trachomatis was examined by electron microscopy. The results presented show that the origin of replication appears to be near the tandem repeats of pCHL2. In addition, replication of the 7.5-kb plasmid is unidirectional, and the copy number during replication is 7-10. The evidence presented suggests that C. trachomatis has a homologue to the Escherichia coli dnaA gene and that this homologue might be involved in replication of the C. trachomatis 7.5-kb plasmid.

An 'empty' sphenoid mucocele

Sphenoid sinus mucoceles behave as mass lesions producing erosion of adjacent bone and cranial nerve palsies. The probable cause is obstruction of the ostia of the sinus. We describe a case which was 'cured' inadvertently by a nasal polypectomy.

Recombinant Escherichia coli clones expressing Chlamydia trachomatis gene products attach to human endometrial epithelial cells

To identify Chlamydia trachomatis genes involved in attachment to host cells, a chlamydial genomic library was screened on the basis of binding characteristics by two methods. In the whole-cell screen, individual recombinant Escherichia coli clones were assayed for adherence to eukaryotic cells. In the membrane-binding screen, each recombinant colony of E. coli was treated with CHCl3 and assayed for binding to purified, 3-[(3-cholamidopropyl)-dimethyl-ammonio]-1-propanesulfonate (CHAPS)-solubilized, 35S-labeled eukaryotic membrane material. Initial screening with McCoy cells was refined by using HEC-1B cells, a human endometrial epithelial cell line, which discriminate among recombinants adhering to McCoy cells. Some recombinants demonstrate significantly greater adherence to HEC-1B cells than to McCoy cells and appear, by transmission electron microscopy, to associate with electron-dense areas of the epithelial cell plasma membrane, resembling coated pits. Recombinants positive by one or both screening methods were examined by Southern and Western (immunoblot) analyses, which revealed the presence of chlamydial sequences inserted in the plasmids and the expression of novel 18-, 28-, and approximately 82 kDa, and perhaps of 18 Maxicell analysis of selected recombinants confirmed that the proteins of 28 and approximately 82 kDa, and perhaps of 18 kDa, are plasmid encoded. Antiserum generated against the recombinant approximately 82-kDa protein reacted in Western analysis with a similar-sized protein from C. trachomatis serovar E elementary bodies (EB) and reticulate bodies, serovar L2 EB, and C. psittaci EB. E. coli JM109(pPBW58) contains a 6.7-kb plasmid insert which encodes proteins of all three sizes. Under a number of different conditions in the whole-cell attachment assay--i.e., at 4 degrees C, in Ca(2+)- and Mg(2+)-free medium, in the presence of trypsin or dextran sulfate, and with rabbit aortic endothelial cells--the binding specificity of JM109(pPBW58) parallels that of C. trachomatis EB. Finally, the adherence phenotype of E. coli JM109(pPBW58) correlates directly with the presence of the recombinant plasmid; the phenotype is lost concurrently with loss of the recombinant plasmid, and the into E. coli JM109. The role of the 18-, 28-, and approximately 82-kDa proteins in mediating attachment, whether they act in concert as a complex or individually, has yet to be determined.

Ascribed role relations between children with mental retardation and their younger siblings

Ascribed, parent-mediated childcare roles of younger same-sex siblings of children with mental retardation were compared to roles assumed by a matched group of comparison siblings. Role reversals were evident for younger siblings of children with mental retardation. These reversals were consistent with roles assumed by the siblings during observed interactions. Increased younger sibling childcare roles were related to less conflicted sibling relationships but were not predictive of friendship or socialization experiences of younger siblings. Younger siblings of children with mental retardation had fewer household chores than did comparison agemates. Children with mental retardation had fewer friendship contacts and out-of-home activities than did their peers without mental retardation. Important within-group differences were evident.

Observations of the role relations and behavior between older children with mental retardation and their younger siblings

Children with mental retardation and their younger siblings without retardation were observed interacting in three naturally occurring in-home contexts (toy play, television viewing, and snack). Comparison siblings without retardation who were matched on age, sex, race, parental marital status, education, and family income were also observed. Interactions between children with retardation and their siblings were characterized by accentuated role asymmetries that favored the younger siblings, whereas the older siblings were dominant in the comparison group. No differences in affect were found between the sibling groups. The competence of the child with mental retardation reliably predicted sibling role asymmetries, and the observational contexts influenced sibling behavior in both groups. Gender differences in roles and behavior were minimal.

Muramic acid is not detectable in Chlamydia psittaci or Chlamydia trachomatis by gas chromatography-mass spectrometry

By using the powerful separation technique of capillary gas chromatography combined with the selectivity of mass spectrometric detection, muramic acid was not detectable in purified elementary bodies of Chlamydia psittaci Cal 10 (less than or equal to 0.006%) or C. trachomatis serovar E (less than or equal to 0.02%). This confirms previous reports which suggested the absence of a typical peptidoglycan in Chlamydia spp.

A low cost modification of an old Leksell stereotactic frame to allow CT-guided stereotaxy

The high cost of commercial CT-compatible stereotactic frames has restricted the availability of CT-guided stereotaxy for many neurosurgical centres. However, many of these centres do possess the standard stereotactic frames for projection radiography, of which the old type Leksell frame is probably the most common. We have devised a simple and low-cost modification to an old Leksell frame to allow CT-guided stereotaxy. The nature of the modifications allow complete freedom of positioning of the frame relative to the CT scanner and coordinate transformations can be performed simply and effectively. The modified frame has been used successfully for some 18 months and the modification has now been performed at two centres in the North West Regional Health Authority. We hope this modification will allow many other centres to embark on CT-guided stereotaxy.

Fixation of fractures of the lower cervical spine using methylmethacrylate and wire: technique and results in 99 patients

Surgical stabilization of traumatic fracture-dislocations of the lower cervical spine with wire and methylmethacrylate remains a controversial procedure. Yet, the resultant immediate fixation with minimal patient morbidity seems to indicate that this method provides an ideal stabilization construct. We describe and report the outcome of a technique of posterior cervical fixation with methylmethacrylate and wire for stabilization of traumatic fractures of the lower cervical spine. Over a 12-year period, 124 fracture-dislocations of the lower cervical spine in 99 patients (mean age, 32 years; range, 15-76 years) were treated at this institution using a posterior methylmethacrylate and wire technique. Eighty-two patients had a posterior element fracture; 28 had a vertebral compression with posterior ligamentous injury; and 14 had a ligamentous injury alone. Thirty-six patients were neurologically intact upon admission, while the rest had radiculopathy or partial or complete myelopathy. Ninety-one patients were available for follow-up [mean, 18.6 months; range, 1-100 months (8.33 years)]. Eighty-eight patients (97%) had a stable fixation and 77 (85%) had resumed preoperative activity or were working but with a residual deficit. Complications included fixation failure requiring a second operation in 3 patients, nonlethal pulmonary embolism in 2 patients, lethal pulmonary embolism in 1 patient, and a superficial wound infection in 3 patients (none affected the underlying fixation construct). These results indicate that this technique is a safe, simple, and effective method for stabilizing the lower cervical spine that allows rapid patient mobility with minimal morbidity.

Entry of genital Chlamydia trachomatis into polarized human epithelial cells

To study the initial invasion process(es) of genital chlamydiae, a model system consisting of hormonally maintained primary cultures of human endometrial gland epithelial cells (HEGEC), grown in a polarized orientation on collagen-coated filters, was utilized. After Chlamydia trachomatis inoculation of the apical surface of polarized HEGEC, chlamydiae were readily visualized, by transmission electron microscopy, in coated pits and coated vesicles. This was true for HEGEC maintained in physiologic concentrations of estrogen (proliferative phase) and of estrogen plus progesterone (secretory phase), despite the finding that association of chlamydiae with secretory-phase HEGEC is significantly reduced (P = 0.025; A.S. Maslow, C.H. Davis, J. Choong, and P.B. Wyrick, Am. J. Obstet. Gynecol. 159:1006-1014, 1988). In contrast, chlamydiae were rarely observed in the clathrin-associated structures if the HEGEC were cultured on plastic surfaces. The same pattern of coated pit versus noncoated pit entry was reproducible in HeLa cells. The quantity of coated pits associated with isolated membrane sheets derived from HeLa cells, grown on poly-L-lysine-coated cover slips in medium containing the female hormones, was not significantly different as monitored by radiolabeling studies and by laser scanning microscopy. These data suggest that culture conditions which mimic in vivo cellular organization may enhance entry into coated pits for some obligate intracellular pathogens.