An assessment of attitudes to, and extent of, the practice of denture marking in South Australia

Denture marking or labelling is not a new concept in either prosthetic or forensic dentistry and its routine practice has been urged by forensic odontologists internationally for many years. In the general community it is often recommended for institutionalized persons to prevent confusion of ownership of dentures. In Australia, the Nursing Home Standards require that dentures of residents be 'discreetly labelled' and marking of all dentures is recommended by the Australian Dental Association. In some countries the marking of dentures is regulated by legislation, but elsewhere there seems to be a reluctance to effect this practice. Various methods which have been proposed include the insertion of an identifying label during the fabrication of the dentures with the utilization of a number of materials and coding systems. This study reports the results of a survey undertaken to determine the extent of the practice of denture marking in South Australia, the methods in use, and the attitudes of dentists, dental technicians and institutions to it. The results indicated that 24.5 per cent of all practitioners providing removable prostheses to their patients include an identifying label as part of the service on some occasions. This included 19.9 per cent of general dental practitioners, 25 per cent of specialist prosthodontists, 57.1 per cent of practitioners with training in forensic odontology, and 43.5 per cent of clinical dental technicians. No practitioner labelled dentures routinely. Reasons cited for not labelling dentures included cost, lack of awareness of standards and recommendations and a belief that it was of little importance.

A cooperative MLT program between a community college and a university

In 1991 the University of Utah collaborated with Salt Lake Community College to establish a jointly sponsored Medical Laboratory Technician (MLT) program. With documented need for MLTs in Utah and surrounding states, both institutions combined their resources to create an associate degree program that neither institution could offer alone. The first academic year of prerequisite science and liberal education courses are completed at the Community College followed by a second year of professional didactic and laboratory courses taught by faculty of the Medical Technology (MT) Program at the University of Utah, Department of Pathology. Following the second year of professional courses, MLT students complete 15 weeks of clinical rotations in the Salt Lake Metropolitan area. MLT students as well as MT students benefit from their shared experiences in combined courses that are taught on the university campus.

Structure of dehydroquinate synthase reveals an active site capable of multistep catalysis

Dehydroquinate synthase (DHQS) has long been regarded as a catalytic marvel because of its ability to perform several consecutive chemical reactions in one active site. There has been considerable debate as to whether DHQS is actively involved in all these steps, or whether several steps occur spontaneously, making DHQS a spectator in its own mechanism. DHQS performs the second step in the shikimate pathway, which is required for the synthesis of aromatic compounds in bacteria, microbial eukaryotes and plants. This enzyme is a potential target for new antifungal and antibacterial drugs as the shikimate pathway is absent from mammals and DHQS is required for pathogen virulence. Here we report the crystal structure of DHQS, which has several unexpected features, including a previously unobserved mode for NAD+-binding and an active-site organization that is surprisingly similar to that of alcohol dehydrogenase, in a new protein fold. The structure reveals interactions between the active site and a substrate-analogue inhibitor, which indicate how DHQS can perform multistep catalysis without the formation of unwanted by-products.

Rotavirus-specific proteins are detected in murine macrophages in both intestinal and extraintestinal lymphoid tissues

Rotaviruses replicate in mature, villous epithelial cells of the mammalian small intestine. Although rotavirus has not been detected in plasma of infants with rotavirus-induced gastroenteritis, rotavirus particles and rotavirus genomic RNA have been detected in extraintestinal sites (e.g. cerebrospinal fluid). Using a murine rotavirus strain well adapted to growth in the small intestines of suckling mice, we found that macrophages (and to a lesser extent B cells) in gut-associated lymphoid tissue contained rotavirus-specific proteins, and that these antigen-containing cells travelled to sites distant to the intestine.

Do stress echocardiography and myocardial perfusion imaging have the same ability to identify the low-risk patient with known or suspected coronary artery disease?

Although both stress myocardial perfusion imaging and echocardiography may have significant prognostic value, the annual death/myocardial infarction rate appears to be much higher in patients with a negative stress echocardiogram. This may greatly limit its ability to act as a "gatekeeper" for additional invasive and interventional procedures.

Intracellular coexpression of epidermal growth factor receptor, Her-2/neu, and p21ras in human breast cancers: evidence for the existence of distinctive patterns of genetic evolution that are common to tumors from different patients

Multiparameter flow cytometry studies were performed on cells from the primary tumors of 94 patients with breast cancer. Correlated cellular measurements of cell DNA content, Her-2/neu, epidermal growth factor receptor (EGFR), and p21ras levels were performed on each of 5,000 to 100,000 cells from each tumor. When criteria for positivity were matched with those in common use for immunohistochemical studies, 28 of 94 (30%) breast cancers were classified as positive for Her-2/neu overexpression. When similar criteria were applied to the EGFR measurements, 23 of 94 (24%) cases were classified as positive for EGFR overexpression. Similarly, 23 of 94 (24%) cases were classified as positive for p21ras overexpression. By conventional flow cytometric criteria for DNA ploidy, 24 cases were diploid, 28 were tetraploid, and 42 were aneuploid. When the measurements were treated as separate sets of data, the only statistically significant correlations noted were the high frequency of diploid tumors, which did not overexpress any of the three oncogenes studied (P < 0.05), and an association between Her-2/neu overexpression and aneuploidy (P < 0.03). When the data were treated as correlated intracellular measurements, 90 of the 94 tumors studied contained a population of cells in which the intracellular levels of Her-2/neu expression were directly correlated with the levels of EGFR expression in the same cells. The ratio of Her-2/neu molecules to EGFR molecules in the same cells exceeded 1 in the majority of tetraploid and aneuploid cases and was close to or less than 1 in the majority of diploid cases. In nearly all tumors, p21ras overexpression was observed only in cells that overexpressed Her-2/neu, EGFR, or both, and p21ras levels per cell were more closely correlated with levels of EGFR per cell in the same cells than with Her-2/neu levels per cell. The data are consistent with a model in which heterodimerization of Her-2/neu and EGFR in individual cells is achieved by one of several genetic evolutionary pathways, all of which commonly lead to p21ras overexpression. The two major genetic evolutionary pathways identified in this study are an aneuploid, Her-2/neu overexpression-driven pathway seen in 59 of 94 tumors, and a diploid, EGFR overexpression-driven pathway seen in 19 of 94 tumors. All tumors with Her-2/neu:EGFR ratios greater than 2 contained an infiltrating ductal carcinoma component, whereas all infiltrating pure lobular carcinomas had Her-2/ neu:EGFR ratios that were less than 2. All of the genetic evolutionary pathways identified in this study were represented among the 11 tumors from patients who experienced early tumor recurrences.

Rapid flow cytometric identification of putative CD14- and CD64- dendritic cells in whole blood

Blood dendritic cells (DCs) may be identified as mononuclear leucocytes with high expression of HLA-DR, but lacking the antigens CD3, CD14, CD16, CD19, and CD56, which are characteristically expressed by T cell, monocytes, B cells, and natural killer cells. However, some DCs have recently been reported to express the monocyte-associated antigen CD14; also some monocytes may shed CD14 and so appear to be CD14-. It is therefore possible that the expression of CD64, which is absent on blood DCs but which is expressed by both CD14+ and CD14- monocytes may better distinguish DCs from monocytes. DCs were identified by flow cytometry as mononuclear leucocytes with the phenotype HLA-DR+, CD2-, CD16-, CD19-, CD57-, and either CD14- or CD64- and hence are described herein as either CD14- DCs or CD64- DCs, respectively. CD14- DCs and CD64- DCs occurred, respectively, at a concentration of 65 +/- 48 x 10(6) cells 1(-1) and 149 +/- 103 x 10(6) cells 1(-1) (mean +/- S.D.) in samples of peripheral blood (corresponding, respectively, to 3.0 +/- 1.8% and 6.6 +/- 3.8% of the mononuclear cells). The expression of CD14 and CD64 on monocytes in blood was also investigated. Cells with the immunophenotype CD14- CD64+ comprised 12.7 +/- 3.3% of the monocyte population and had high expression of HLA-DR. DCs identified as CD14- or CD64- were isolated by flow cytometric sorting, prepared for electron microscopy, and both were found to have the characteristic morphology of resting DCs. We conclude that mononuclear cells with the phenotype HLA-DR+, CD3-, CD16-, CD19-, CD56-, and CD64- are blood DCs that may be CD14+ or CD14-. The method described therefore provides a more accurate and rapid means of identifying circulating DCs.

Pure cut electrocautery current for sphincterotomy causes less post-procedure pancreatitis than blended current

BACKGROUND

Complications after endoscopic biliary sphincterotomy occur in 8% to 10% of patients when studied prospectively. It is not known whether the type of electrocautery current affects this rate. Theoretically, less edema of the ampulla after a pure cutting current sphincterotomy could decrease the risk of pancreatitis although the risk of postsphincterotomy hemorrhage might be greater.

METHODS

One hundred seventy patients undergoing sphincterotomy were prospectively randomized to either a blended or pure cut current on the Valleylab electrosurgical unit. The settings were a blended three current at a power setting of 30 watts/sec for both the cut and coagulation currents or a pure cut current at a power setting of 30 watts/sec. The individual determining whether a complication occurred was blinded to the type of current used, and all patients were hospitalized for 24 hours post-procedure. Pancreatitis was defined as mild if fewer than 5 days, moderate if 5 to 14 days, and severe if more than 14 days of hospitalization were required.

RESULTS

Indications for sphincterotomy were choledocholithiasis in 111 patients, sphincter of Oddi dysfunction in 36 patients, stent placement in 15 patients, and miscellaneous in 8 patients. There were a total of 16 complications in 170 patients (9%); 4 (5%) were in the pure cut current group of 86 patients (one episode of bleeding that required transfusion of 4 U and three episodes of mild pancreatitis), and 12 (14%) were in the blended current group of 84 patients (7 mild, 2 moderate, and 1 severe pancreatitis; 1 case of cholangitis; and one episode of bleeding that required transfusion of 2 U). There were significantly fewer complications in the pure cut group (p < 0.05 by chi-square).

CONCLUSION

The use of pure cut current is associated with a lower incidence of pancreatitis, the most common ERCP complication, than with blended current sphincterotomy. An insufficient number of patients were studied to comment on the relative risk of hemorrhage. However, because the complication of hemorrhage is much less common than pancreatitis, pure cut current is safer overall.

Binucleated and multinucleated forms of plasma cells in synovia from patients with rheumatoid arthritis

A morphological examination of synovial tissue from 25 patients with rheumatoid arthritis revealed that binucleated or multinucleated plasma cells were present in all samples and absent in synovia obtained from 16 control patients. Plasma cells containing two, three of four nuclei constitute a mean 3% of the total plasma cell population. They were always found amongst plasma cell infiltrates and in close association with small blood vessels. Ultrastructural analysis found no evidence of cellular membranes separating the individual nuclei in binucleated or multinucleated plasma cells, suggesting that the cells did not arise from fusion. Some of these plasma cells had a diameter approaching 100 microns, and many were in intimate contact with macrophages. The demonstration of a few cells with mitotic figures within the infiltrates suggests that the maintenance of plasma cell numbers in rheumatoid synovium may depend, in part, upon their local proliferation.

Minimal criteria for placement of adults on the liver transplant waiting list: a report of a national conference organized by the American Society of Transplant Physicians and the American Association for the Study of Liver Diseases

This report summarizes a recent meeting cosponsored by the American Society of Transplant Physicians and the American Association for the Study of Liver Diseases to formulate minimal criteria by which patients with severe liver disease will be placed on the waiting list for liver transplantation. The participants agreed that only patients in immediate need of liver transplantation should be placed on the waiting list. Patients should not be placed in anticipation of some future need for such therapy. It was agreed that minimal criteria could assist but not replace the clinical judgment of the transplant professionals at individual centers. The criteria will be summarized below for adult patients with acute or chronic liver disease. The most important non-disease-specific criterion for placement on the transplant waiting list was an estimated 90% chance of surviving 1 year. This translated into a Child-Pugh score of > or = 7 for patients with cirrhosis which places the patient in Child-Pugh class B or C. Cirrhotic patients who have experienced gastrointestinal bleeding caused by portal hypertension or a single episode of spontaneous bacterial peritonitis would meet the minimal criteria irrespective of their Child-Pugh score. There were disease-specific criteria also. These include a sole minimal criterion for patients with fulminant hepatic failure regardless of etiology of the onset of stage 2 hepatic encephalopathy. A requirement for 6 months abstinence from alcohol before placement on the transplant waiting list was considered appropriate for most patients with alcoholic liver disease. Exceptional cases could get access to the waiting list through a regional review process. Chronic cholestatic diseases present difficulties because of a different natural history than that of chronic hepatocellular diseases. The use of specific risk scores for primary biliary cirrhosis and primary sclerosing cholangitis will likely replace Childs-Pugh classification as the scoring systems become refined. Minimal criteria for any patient with a primary hepatocellular cancer would admit any patient with a tumor confined to the liver irrespective of size or number of tumors, after careful investigation had failed to show spread to lymph nodes, the portal vein, or distant organs. Unusual or rare indications for liver transplantation, including Budd-Chiari syndrome, Wilson's disease, and other hereditary disorders, were also discussed. Finally, it was agreed that there should be no absolute contraindications to placement of patients on the liver transplant waiting list. These criteria should be open to regular review to accommodate advances in the field.

A risk profile of emergency room adult trauma victims: intentional versus unintentional trauma injuries

This article presents a prospective study of 285 adult trauma victims admitted to a Los Angeles inner-city level 1 trauma center, from November 1991 to February 1992. The purpose of this study was to determine the magnitude of intentional and unintentional trauma injuries in this adult patient population, and to identify sociodemographic, lifestyle and medical risk factors predisposing patients to intentional vs. unintentional trauma injury. Chi-square analysis revealed that intentional trauma victims and unintentional trauma victims significantly differ in 8 of 13 risk factors. The resulting risk profile indicated that intentional trauma victims were more likely to be between the ages of 16-29 years old; African American males and more likely to present to the emergency room with injury severity scores higher than 15 (indicating severe injuries) than unintentional trauma victims. Strategies for prevention and medical social work intervention are discussed.

Blood polymorphonuclear leukocytes from the majority of sickle cell patients in the crisis phase of the disease show enhanced adhesion to vascular endothelium and increased expression of CD64

There is increasing interest in the role of blood polymorphonuclear leukocytes (PMNs) in the pathogenesis of sickle cell crisis. We studied the adherence of PMNs from 18 sickle cell patients in crisis, 25 out of crisis, and 43 healthy subjects (controls) to monolayers of human umbilical cord endothelium that were either untreated or pretreated with tumor necrosis factor alpha (TNFalpha). Overall, the PMNs from patients in crisis were more adherent than control PMNs to untreated endothelial monolayers (mean 53% increase; P < .001) and TNFalpha-treated monolayers (mean 41% increase; P < .002). Increased adhesiveness was not associated with an abnormal expression of CD11a, CD11b, CD11c, CD18, CD62L, or CD15. There was an increase in the number of PMNs expressing CD64 in patients in crisis (median value, 44%) compared with patients out of crisis (median, 21%; P = .025) and controls (median, 6.5%; P < .001). Sera from patients in crisis had normal levels of granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, interferon-gamma, TNFalpha, interleukin-1 (IL-1), IL-6, or IL-8 and did not modify the adherence of PMNs or their expression of CD64. Only IFN-gamma induced CD64 expression on PMNs, but this effect was not associated with enhanced binding to endothelium. Because PMNs bound to endothelial monolayers were CD64(+) and CD64-enriched PMNs were 7 times more adherent to endothelial monolayers than CD64-depleted PMNs, it is likely that CD64 is a marker of adherent PMNs. Two of the three anti-CD64 antibodies used in our antibody blocking studies (clones 32.2 and 197) partially inhibited the binding of sickle cell PMNs to untreated endothelium (mean inhibitions of 33% [P = .01] and 21% [P = .03], respectively), whereas only one (clone 197) inhibited binding to TNFalpha-treated endothelium (mean inhibition, 29%; P = . 004). In some patients with sickle cell disease, an enhanced PMN adhesion to vascular endothelium could contribute to the vascular occlusion that characterizes the acute crisis of the disease.

Molecular scanning of the human peroxisome proliferator activated receptor gamma (hPPAR gamma) gene in diabetic Caucasians: identification of a Pro12Ala PPAR gamma 2 missense mutation

Peroxisome proliferator activated receptor-gamma (PPAR gamma) is a nuclear receptor that regulates adipocyte differentiation, and possibly lipid metabolism and insulin sensitivity. As such, PPAR gamma is a promising candidate gene for several human disorders including obesity and type 2 diabetes mellitus. Screening for mutations in the entire coding region of the PPAR gamma gene (both gamma 1 and gamma 2 isoforms) was performed with DNA of 26 diabetic Caucasians with or without obesity. Two base substitutions were identified: a silent mutation at nucleotide 1431 (CACHis-->CATHis) and a missense mutation (CCGPro-->GCGAla) at codon 12 of PPAR gamma 2. The allele frequency of the Pro12Ala PPAR gamma 2 variant was 0.12 in Caucasian Americans, 0.10 in Mexican Americans, 0.08 in Samoans, 0.03 in African Americans, 0.02 in Nauruans, and 0.01 in Chinese. We conclude that the Pro12Ala PPAR gamma 2 gene variant is present in diverse populations. Further studies of the Pro12Ala variant will determine its relevance to obesity, insulin resistance, and type 2 diabetes.

Purification and characterization of recombinant catalase-peroxidase, which confers isoniazid sensitivity in Mycobacterium tuberculosis

The Mycobacterium tuberculosis katG gene encodes a dual-function enzyme called catalase-peroxidase, which confers sensitivity in M. tuberculosis to isonicotinic acid hydrazide. We have constructed a system for the high level expression of a recombinant form of this enzyme by amplifying the katG gene from the pYZ56 construct (1) and subcloning into a vector suitable for expression in Escherichia coli. The resulting plasmid, pTBCP, produced the catalase-peroxidase in large quantities, corresponding to 30% of total cell protein. The enzyme has been purified to homogeneity and appears to be a dimer in the native form. Using either hydrogen peroxide or t-butyl hydroperoxide and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) as substrates, kcat and Km values have been obtained for both catalatic and peroxidatic activities, respectively. The availability of significant quantities of an active, folded, recombinant form of M. tuberculosis catalase-peroxidase should thus facilitate future studies of its role in drug activation and antibiotic resistance.

Aqueous-based microcapsules are detected primarily in gut-associated dendritic cells after oral inoculation of mice

We previously found that aqueous-based microencapsulation enhanced virus-specific humoral immune responses after oral inoculation of mice. However, the mechanism by which microencapsulation enhances immunogenicity remains unclear. We found that spermine-alginate microcapsules were detected primarily in gut-associated dendritic cells (i.e. CD11c/CD18+, Ia+, CD11b-, CD45R-) after oral inoculation of adult mice. Microencapsulation may enhance immunogenicity by involving antigen presenting cells which are more efficient than those recruited during natural infection.