Patients with prosthetic joints: Are they at risk when receiving invasive dental procedures?

Most prosthetic joint infections (PJI) are due to wound contamination at the time of surgery. Some infections occur due to the hematogenous spread of bacteria from distant sites of infection. A review of the literature fails to associate PJI with transient bacteremias from invasive dental procedures. Several authors have described conditions which, they believe, render patients with prosthetic joints more at risk for infection. Prosthetic joint patients with these "high risk" conditions have the same types of infecting organisms as other patients with PJI. This indicates that the infecting bacteria are from wound contamination or distant sites of infection and not related to dental procedure bacteremias. Based on this review, antibiotic prophylaxis is not indicated for patients with prosthetic joints when receiving invasive dental procedures, since there is no proven benefit and there are known risks involved with the use of antibiotics. However, the American Dental Association (ADA) and the American Academy of Orthopaedic Surgeons (AAOS), in an advisory statement, suggest prophylaxis for "high risk" patients. The ADA and AAOS recommend a single dose of amoxicillin, cephradine, or clindamycin when prophylaxis is selected. The dentist is ultimately responsible for making treatment recommendations for his or her patients.     

Pharmaceutical Marketing: Implications for Medical Residency Training

An educational intervention was developed to improve family practice residents' ability to obtain useful information from pharmaceutical representatives. The curriculum is based on the traditional one-on-one drug detail. The objectives are to develop residents' skills in controlling the interview, promote skills for critically analyzing drug-promotional material, and discuss ethical issues. The contents include an assessment tool, suggested readings, and interview questions with rationale. After 5 years, residents' confidence in all areas of the curriculum improved significantly.     

SNAP-II predicts mortality among infants with congenital diaphragmatic hernia.

OBJECTIVE: Outcomes analysis in congenital diaphragmatic hernia (CDH) requires a validated risk-adjustment tool. The purpose of this study was to use the Canadian Neonatal Network (CNN) database to validate the Score for Neonatal Acute Physiology, Version II (SNAP-II) for prediction of mortality among CDH infants admitted to a neonatal intensive care unit (NICU), and to compare this to the predictive equation recently developed by the Congenital Diaphragmatic Hernia Study Group (CDHSG). STUDY DESIGN: Infants with CDH in the CNN database were identified. Bivariate and multivariable logistic regression models were used to identify risk factors predictive of mortality. Model predictive performance and calibration were assessed using the area under the receiver operator characteristic curve and the technique of Hosmer-Lemeshow, respectively, and compared with the CDHSG predictive equation. RESULTS: There were 88 patients with CDH among 19,507 admissions to CNN hospitals. The mortality rate among CDH patients surviving to NICU admission was 17%, and 12.5% received extracorporeal membrane oxygenation therapy. Gestational age and admission SNAP-II score predicted mortality. Model predictive performance and calibration were optimized with these variables combined. The CDHSG equation was equally predictive of mortality, but was only marginally calibrated. CONCLUSIONS: SNAP-II is highly predictive of mortality among patients with CDH, and can be used to risk-adjust these patients.     

PET measurement of cardiac and nigrostriatal denervation in Parkinsonian syndromes.

Scintigraphic imaging with (123)I-metaiodobenzylguanidine ((123)I-MIBG) has demonstrated extensive losses of cardiac sympathetic neurons in idiopathic Parkinson's disease (IPD). In contrast, normal cardiac innervation has been observed in (123)I-MIBG studies of multiple-system atrophy (MSA) and progressive supranuclear palsy (PSP). Consequently, it has been hypothesized that cardiac denervation can be used to differentiate IPD from MSA and PSP. We sought to test this hypothesis by mapping the distribution of cardiac sympathetic neurons in patients with IPD, MSA, and PSP by using PET and (11)C-meta-hydroxyephedrine ((11)C-HED). Also, the relationship between cardiac denervation and nigrostriatal denervation was investigated by measuring striatal presynaptic monoaminergic nerve density with PET and (11)C-dihydrotetrabenazine ((11)C-DTBZ). METHODS: (11)C-HED and (11)C-DTBZ scans were obtained for patients with IPD (n = 9), MSA (n = 10), and PSP (n = 8) and for age-matched control subjects (n = 10). Global and regional measurements of (11)C-HED retention were obtained to assess the extent of cardiac sympathetic denervation. (11)C-DTBZ binding was measured in the caudate nucleus, anterior putamen, and posterior putamen. RESULTS: As expected, extensive cardiac denervation was observed in several of the patients with IPD. However, substantial cardiac denervation was also seen in some patients with MSA and PSP. (11)C-DTBZ studies demonstrated striatal denervation in all patients with IPD and in most patients with MSA and PSP. No correlation was found between cardiac (11)C-HED retention and striatal (11)C-DTBZ binding. CONCLUSION: Cardiac sympathetic denervation was found to occur not only in IPD but also in other movement disorders, such as MSA and PSP. This finding implies that scintigraphic detection of cardiac sympathetic denervation cannot be used independently to discriminate IPD from other movement disorders, such as MSA and PSP. Cardiac sympathetic denervation was not correlated with striatal denervation, suggesting that the pathophysiologic processes underlying cardiac denervation and striatal denervation occur independently in patients with parkinsonian syndromes. These findings provide novel information about central and peripheral denervation in patients with neurodegenerative disorders.     

Goldenhar and cri-du-chat syndromes: a contiguous gene deletion syndrome?

We report a full-term male infant born to nonconsanguinous parents who had clinical features of Goldenhar syndrome and cri du chat syndrome. At birth, the infant was noted to have dysmorphic features with bilateral preauricular tags, rotated ears, bilateral epicanthic folds, a left epibulbar lipodermoid, and an accessory left nipple. After he was assessed for feeding difficulty and tachypnea, he was found to have esophageal atresia with tracheoesophageal fistula. In addition, he had a high-pitched, cat-like cry, characteristic of cri-du-chat syndrome. He also failed a hearing test. Chromosomal analysis and fluorescence in situ hybridisation studies showed an unbalanced karyotype with a terminal deletion of the segment p14 on the short arm of chromosome 5, which is consistent with the cri-du-chat locus. The association of Goldenhar syndrome and cri-du-chat syndrome in this patient suggests that the chromosome 5p14 locus may harbor a gene implicated with Goldenhar syndrome.     

Canine pancreas and kidney transplantation following total-lymphoid irradiation

The effect of total-lymphoid irradiation on survival of canine pancreas and kidney allografts was studied. TLI had a marked immunosuppressive effect as measured by in vitro immune responses and reduced circulating leukocytes. Despite the changes, median graft survival times for animals treated with 800 cGy (9 days) or 1800 cGy (9.5 days) were not significantly different from untreated control animals (7 days). The addition of low-dose antithymocyte globulin (10 mg/kg/day) on post-transplant days 0, 2, 4, 6, 8, and 10 had no measurable synergistic effect. Similarly, median segmental pancreas allograft survival times after 1700-2200 cGy of TLI treatment (16.5 days) were only marginally longer than those of untreated controls (9 days). The only animal to maintain a graft for greater than 200 days was matched to the donor in mixed lymphocyte culture (MLC). This animal was able to reject a third-party skin graft after 8 days while a graft from the original donor was still surviving after 21 days when the pancreas graft failed from a chronic-type rejection. These results indicate that TLI alone or in combination with ATG will not be predictably effective as a method of prolonging allograft survival. The role of matching major histocompatibility complex antigens in TLI treatment requires clarification.     

Syphilis: an update.

Syphilis can be spread during the practice of dentistry by direct contact with mucosal lesions of primary and secondary syphilis or blood and saliva from infected patients. The dentist also can play an important role in the control of syphilis by identification of the signs and symptoms of syphilis, patient education, and referral. The incidence of syphilis and the impact of control measures are presented with the emphasis on the past 5 years. The signs and symptoms of primary, secondary, latent, and late (tertiary) syphilis are reviewed. Current medical treatment is presented. The oral manifestations of syphilis are discussed as well as the dental management of the infected patient.     

Optimal timing of a single dose of zoledronic acid to increase strength in rat fracture repair.

We hypothesized that ZA treatment would bolster fracture repair. In a rat model for closed fracture healing, a single dose of ZA at 0, 1, or 2 wk after fracture significantly increased BMC and strength of the healed fracture. Delaying the dose (1 or 2 wk after fracture) displayed superior results compared with dosing at the time of fracture. INTRODUCTION: Bisphosphonates are known to increase bone strength and thus the resistance to fracture by decreasing osteoclastic bone resorption. These properties may enable bisphosphonates to also increase the strength of fracture repair. Zoledronic acid (ZA) is a potent bisphosphonate with a high affinity for bone mineral, allowing bolus intravenous dosing in a range of indications. In this study, we examined the application of bolus dose ZA in endochondral fracture repair. MATERIALS AND METHODS: Carbon-14 labeled ZA was used in a closed rat fracture model. Rats were divided into five treatment groups (n = 25 per group): saline control, local ZA (0.01 mg/kg), and three systemic bolus ZA groups (0.1 mg/kg) with different administration times: at fracture, 1 wk after fracture, and 2 wk after fracture. Rats were killed 6 wk postoperatively. Postmortem analyses included radiography, QCT, microCT, biomechanical testing, scintillation counting, autoradiography, and histology. RESULTS: Single-dose systemic ZA administration significantly increased callus volume, callus BMC, and mechanical strength. Perioperative treatment increased mechanical strength by 30% compared with controls (p < 0.05). Administering the systemic dose at 1 or 2 wk after fracture further increased mechanical strength compared with controls by 44% and 50%, respectively (p < 0.05). No significant differences in mechanical parameters were seen with local injection at the dose studied. Autoradiographic analysis indicated that ZA binds significantly to bone that is present at the time of administration. ZA quantification indicated that delayed administration significantly increased the uptake efficiency in the callus. Histological and microCT analysis showed that ZA treated calluses had a distinctive internal structure consisting of an intricate network of retained trabecular bone. CONCLUSIONS: The timing of a single systemic dose of ZA plays an important role in the modulation of callus properties in this rat fracture model; delaying the single dose produces a larger and stronger callus.