Gabapentin for Postoperative Pain Control and Opioid Reduction in Scrotal Surgery: A Randomized Controlled Clinical Trial

PURPOSE

To assess the safety and efficacy of gabapentin in reducing postoperative pain among patients undergoing scrotal surgery for male infertility by conducting a randomized, double-blind, placebo-controlled trial.

MATERIALS AND METHODS

In this randomized, double-blind, placebo-controlled trial, healthy men undergoing scrotal surgery with a single surgeon were randomized to receive either (1) gabapentin 600 mg given 2 hours preoperatively and 300 mg taken 3 times a day postoperatively for 3 days, or (2) inactive placebo. The primary outcome measure was difference in postoperative pain scores. Secondary outcomes included differences in opioid usage, patient satisfaction, and adverse events.

RESULTS

Of 97 patients screened, 74 enrolled and underwent randomization. Of these, 4 men were lost to follow-up, and 70 were included in the final analysis (35 gabapentin, 35 placebo). Both differences in initial postoperative mean pain score (-1.14, 95% CI -2.21 to -0.08, P = .035) and final mean pain score differences (-1.27, 95% CI -2.23 to -0.32, P = .0097) indicated lower gabapentin pain compared to placebo. There were no statistically significant differences in opioid usage, patient satisfaction, or adverse events.

CONCLUSIONS

These data suggest that perioperative gabapentin results in a statistically and clinically significant decrease in pain following scrotal surgery. While there was no evidence of an impact on opioid usage or patient satisfaction, given the low risk of adverse events, it may be considered as part of a multimodal pain management strategy.

Pain, Analgesic Use, and Patient Satisfaction With Spinal Versus General Anesthesia for Hip Fracture Surgery : A Randomized Clinical Trial

BACKGROUND

The REGAIN (Regional versus General Anesthesia for Promoting Independence after Hip Fracture) trial found similar ambulation and survival at 60 days with spinal versus general anesthesia for hip fracture surgery. Trial outcomes evaluating pain, prescription analgesic use, and patient satisfaction have not yet been reported.

OBJECTIVE

To compare pain, analgesic use, and satisfaction after hip fracture surgery with spinal versus general anesthesia.

DESIGN

Preplanned secondary analysis of a pragmatic randomized trial. (ClinicalTrials.gov: NCT02507505).

SETTING

46 U.S. and Canadian hospitals.

PARTICIPANTS

Patients aged 50 years or older undergoing hip fracture surgery.

INTERVENTION

Spinal or general anesthesia.

MEASUREMENTS

Pain on postoperative days 1 through 3; 60-, 180-, and 365-day pain and prescription analgesic use; and satisfaction with care.

RESULTS

A total of 1600 patients were enrolled. The average age was 78 years, and 77% were women. A total of 73.5% (1050 of 1428) of patients reported severe pain during the first 24 hours after surgery. Worst pain over the first 24 hours after surgery was greater with spinal anesthesia (rated from 0 [no pain] to 10 [worst pain imaginable]; mean difference, 0.40 [95% CI, 0.12 to 0.68]). Pain did not differ across groups at other time points. Prescription analgesic use at 60 days occurred in 25% (141 of 563) and 18.8% (108 of 574) of patients assigned to spinal and general anesthesia, respectively (relative risk, 1.33 [CI, 1.06 to 1.65]). Satisfaction was similar across groups.

LIMITATION

Missing outcome data and multiple outcomes assessed.

CONCLUSION

Severe pain is common after hip fracture. Spinal anesthesia was associated with more pain in the first 24 hours after surgery and more prescription analgesic use at 60 days compared with general anesthesia.

PRIMARY FUNDING SOURCE

Patient-Centered Outcomes Research Institute.

Impact of preoperative opioid use disorder on outcomes following lumbar-spine surgery

OBJECTIVES

Opioid use disorder (OUD) has previously been shown to negatively impact postoperative outcomes. As the number of spine surgeries continues to rise annually, more patients with preexisting OUD will be seen in operating rooms. Our retrospective cohort study aims to expand on the independent association between preoperative OUD and outcomes following lumbar-spine surgery.

PATIENTS AND METHODS

Using 2007-2014 data from the State Inpatient Databases (SID) for the states of California (2007-2011), Florida, New York, Maryland, and Kentucky, we identified patients ≥18 years of age undergoing lumbar-spine surgery. Our primary variable of interest was present-on-admission OUD. Outcomes of interest included a range of postoperative complications divided into those specific to spinal surgery and general surgical complications, length of stay (LOS), 30- and 90-day readmission rates, and total hospital charges.

RESULTS

Of the 267,976 patients undergoing lumbar-spine surgery, 1902 patients were identified as having OUD. After adjusting for patient- and hospital-level confounders, we found that patients with OUD were more likely to experience complications related specifically to spine surgery (aOR = 1.51, 95%CI = 1.33-1.71) as well as general postoperative complications (aOR = 1.63, 95%CI = 1.36-1.96) compared to those without OUD. OUD was additionally associated with longer LOS (aIRR = 1.29, CI = 1.24-1.34) and higher total charges (aIRR = 1.14, CI = 1.11-1.18). Whereas no statistically significant difference was detected for 30-day-readmission rates, patients with OUD experienced higher rates of readmission within 90 days of discharge (aOR = 1.20, CI = 1.08-1.35).

CONCLUSIONS

Our study strengthens the evidence that patients with OUD fare poorly after lumbar-spine surgery. More research is needed to determine whether reducing opioid use before surgery can mitigate the postoperative risks associated with OUD.

Hospital safety-net burden is associated with increased inpatient mortality after elective total knee arthroplasty: a retrospective multistate review, 2007-2018

BACKGROUND

Total knee arthroplasty (TKA) is among the most common surgical procedures performed in the USA and comprises an outsized proportion of Medicare expenditures. Previous work-associated higher safety-net burden hospitals with increased morbidity and in-hospital mortality following total hip arthroplasty. Here, we examine the association of safety-net burden on postoperative outcomes after TKA.

METHODS

We retrospectively analyzed 1 141 587 patients aged ≥18 years undergoing isolated elective TKA using data from the State Inpatient Databases for Florida, Kentucky, Maryland, New York and Washington from 2007 through 2018. Hospitals were grouped into tertiles by safety-net burden status, defined by the proportion of inpatient cases billed to Medicaid or unpaid (low: 0%-16.83%, medium: 16.84%-30.45%, high: ≥30.45%). Using generalized estimating equation models, we assessed the association of hospital safety-net burden status on in-hospital mortality, patient complications and length of stay (LOS). We also analyzed outcomes by anesthesia type in New York State (NYS), the only state with this data.

RESULTS

Most TKA procedures were performed at medium safety-net burden hospitals (n=6 16 915, 54%), while high-burden hospitals performed the fewest (n=2 04 784, 17.9%). Overall in-patient mortality was low (0.056%), however, patients undergoing TKA at medium-burden hospitals were 40% more likely to die when compared with patients at low-burden hospitals (low: 0.043% vs medium: 0.061%, adjusted OR (aOR): 1.40, 95% CI 1.09 to 1.79, p=0.008). Patients who underwent TKA at medium or high safety-net burden hospitals were more likely to experience intraoperative complications (low: 0.2% vs medium: 0.3%, aOR: 1.94, 95% CI 1.34 to 2.83, p<0.001; low: 0.2% vs high: 0.4%, aOR: 1.91, 95% CI 1.35 to 2.72, p<0.001). There were no statistically significant differences in other postoperative complications or LOS between the different safety-net levels. In NYS, TKA performed at high safety-net burden hospitals was more likely to use general rather than regional anesthesia (low: 26.7% vs high: 59.5%, aOR: 4.04, 95% CI 1.05 to 15.5, p=0.042).

CONCLUSIONS

Patients undergoing TKA at higher safety-net burden hospitals are associated with higher odds of in-patient mortality than those at low safety-net burden hospitals. The source of this mortality differential is unknown but could be related to the increased risk of intraoperative complications at higher burden centers.

Cannabis, anesthesia and acute postoperative pain: known and unknown

Tweetable abstract Cannabis use may significantly affect anesthetic, perioperative and acute pain management care; but research needs to be standardized, expanded and more inclusive.

Opioid use disorder and maternal outcomes following cesarean delivery: a multistate analysis, 2007-2014

Aim: To examine the association between opioid use disorder (OUD) and maternal outcomes following cesarean delivery. Methods: Retrospective analysis of over 2.4 million discharge records for in-patient cesarean delivery across five states from 2007 to 2014. Primary outcome was in-hospital mortality. Secondary outcomes included length of stay (LOS) and 30- and 90-day readmission rates. Results: OUD patients were 148% more likely than non-OUD patients to die during hospitalization (adjusted odds ratios [aOR]: 2.48, 95% CI: 1.20, 5.10; p < 0.05). OUD was associated with increased odds of 30-day readmission (aOR: 1.46, 95% CI: 1.30, 1.65; p < 0.001) and 90-day readmission (aOR: 1.70, 95% CI: 1.55, 1.88; p < 0.001); LOS was not significantly different. Conclusion: OUD predicts increased in-patient mortality and odds of 30- and 90-day readmission following cesarean delivery.

Chronic pain diagnosis in refugee torture survivors: A prospective, blinded diagnostic accuracy study

BACKGROUND

An estimated 87% of torture survivors experience chronic pain such as brachial plexopathy from upper extremity suspension or lumbosacral plexus injury from leg hyperextension. However, a vast majority of pain is undetected by evaluators due to a lack of diagnostic tools and confounding psychiatric illness. This diagnostic gap results in exclusive psychological treatment rather than multimodal therapies, substantially limiting rehabilitation. We hypothesized that the United Nations Istanbul Protocol (UNIP) would have a sensitivity of approximately 15% for pain detection, and that the use of a validated pain screen would improve its sensitivity by at least 29%, as compared to the reference standard (pain specialist evaluation).

METHODS AND FINDINGS

This prospective blind-comparison-to-gold-standard study of survivors of torture, as defined by the World Medical Association, took place at Weill Cornell Medicine between February 1, 2017, and June 21, 2019. 11 women and 9 men, for a total of 20 participants, were included in the analysis. Five participants received 2 UNIP evaluations, for a total of 25 unique evaluations included in the analysis. Participants were representative of a global population, with home countries in Africa, Central America, South Asia, the Caribbean, and the Middle East. Methods of torture experienced were homogeneous, following the predictable pattern of systematic torture. Participants first received the standard evaluation protocol for torture survivors (UNIP) by a trained evaluator, and subsequently received a validated pain screen (Brief Pain Inventory-Short Form [BPISF]) followed by a noninvasive examination by a pain specialist physician (reference standard). The primary outcome was the diagnostic and treatment capability of the standard protocol (index test) versus the validated pain screen (BPISF), as compared to the reference standard. Trained evaluators performing the initial assessment with the UNIP (index test) were blinded to the study, and the pain specialist physician (reference standard) was blinded to the outcome of the initial UNIP evaluation and the BPISF; data from the initial UNIP assessment were not gathered by the principal investigator until all other study procedures were completed. Providers using only the UNIP captured pain in a maximum of 16% of evaluations, as compared to 85% of participants being diagnosed with pain by the reference standard. When employed, the validated pain screen had a sensitivity of 100% (95% CI 72%-100%) and a negative predictive value of 100%, as compared to a sensitivity of 24% (95% CI 8%-50%) and a negative predictive value of 19% (95% CI 5%-46%) for the index test. The difference in the sensitivity of the UNIP as compared to the BPISF was significant, with p < 0.001. No adverse events owing to participation in the study were reported by participants. Limitations of the study include small sample size, its single-site nature, and the exclusion of individuals who did not speak 1 of the 5 study languages.

CONCLUSIONS

These data indicate that a validated pain screen can supplement the current global standard assessment of torture survivors, the UNIP, to increase the accuracy of pain diagnosis.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03018782.

Preexisting Opioid Use Disorder and Outcomes After Lower Extremity Arthroplasty: A Multistate Analysis, 2007–2014

Objective

The aim of this study was to examine the association of preexisting opioid use disorder and postoperative outcomes in patients undergoing total hip or knee arthroplasty (THA and TKA, respectively) in the overall population and in the Medicare-only population.

Methods

This retrospective cohort study examined data from the State Inpatient Databases of the Healthcare Cost and Utilization Project for the years 2007–2014 from California, Florida, New York, Maryland, and Kentucky. We compared patients with and without opioid use disorders on unadjusted rates and calculated adjusted odds ratios (aORs) of in-hospital mortality, postoperative complications, length of stay, and 30-day and 90-day readmission status; analyses were repeated in a subgroup of Medicare insurance patients only.

Subjects

After applying our exclusion criteria, our study included 1,422,210 adult patients undergoing lower extremity arthroplasties, including 818,931 Medicare insurance patients. In our study, 0.4% of THA patients and 0.3% of TKA patients had present-on-admission opioid use disorder.

Results

Opioid use disorder patients were at higher risk for in-hospital mortality (aOR = 3.10), 30- and 90-day readmissions (aORs = 1.81, 1.81), and pulmonary and infectious complications (aORs = 1.25, 1.96).

Conclusions

Present-on-admission opioid use disorder was a risk factor for worse postoperative outcomes and increased health care utilization in the lower extremity arthroplasty population. Opioid use disorder is a potentially modifiable risk factor for mortality, postoperative complications, and health care utilization, especially in the at-risk Medicare population.

Disparities in mortality after abdominal aortic aneurysm repair are linked to insurance status

OBJECTIVE

The objective of this study was to determine differences in mortality after abdominal aortic aneurysm (AAA) repair based on insurance type.

METHODS

In this retrospective cohort study, data from all-payer patients in nonpsychiatric hospitals in New York, Maryland, Florida, Kentucky, and California from January 2007 to December 2014 (excluding California, ending December 2011) were extracted from the State Inpatient Databases, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. There were 90,102 patients ≥18 years old with available insurance data who underwent open AAA repair or endovascular aneurysm repair (EVAR) identified using International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes 3844, 3925, and 3971. EVAR patients were identified using the procedure code 3971, and the remainder of cases were categorized as open. Patients were divided into cohorts by insurance type as Medicare, Medicaid, uninsured (self-pay/no charge), other, or private insurance. Patients were further stratified for subgroup analyses by procedure type. Unadjusted rates of in-hospital mortality, the primary outcome, as well as secondary outcomes, such as surgical urgency, 30-day and 90-day readmissions, length of stay, total charges, and postoperative complications, were examined by insurance type. Adjusted odds ratios (ORs) for in-hospital mortality were calculated using multivariate logistic regression models fitted to the data. The multivariate models included patient-, surgical-, and hospital-specific factors with bivariate baseline testing suggestive of association with insurance status in addition to variables that were selected a priori.

RESULTS

Medicaid and uninsured patients had the highest rates of mortality relative to private insurance beneficiaries in all cohorts. Medicaid patients incurred a 47% increase in the odds of mortality, the highest among the insured, after all AAA repairs (OR, 1.47; 95% confidence interval [CI], 1.23-1.76), whereas uninsured patients experienced a 102% increase in the odds of mortality (OR, 2.02; 95% CI, 1.54-2.67). Subgroup analyses for open AAA repair and EVAR corroborated that Medicaid insurance (open repair OR, 1.37 [95% CI, 1.14-1.64]; EVAR OR, 2.06 [95% CI, 1.40-3.04]) and uninsured status (open repair OR, 1.85 [95% CI, 1.35-2.54]; EVAR OR, 2.96 [95% CI, 1.82-4.81]) were associated with the highest odds of mortality after both procedures separately.

CONCLUSIONS

This study demonstrates that Medicaid insurance and uninsured status are associated with higher unadjusted rates and adjusted ORs for in-hospital mortality after AAA repair relative to private insurance status. Primary payer status therefore serves as an independent predictor of the risk of death subsequent to AAA surgical interventions.

Pre-existing opioid use disorder and postoperative outcomes after appendectomy or cholecystectomy: A multi-state analysis, 2007-2014

INTRODUCTION AND OBJECTIVES

Opioid use disorder has become increasingly prevalent in recent years. Previous studies have shown that patients with opioid use disorder undergoing orthopedic, elective abdominopelvic, and cardiac procedures have poorer postoperative outcomes. The aim of this study was to examine the effect of pre-existing opioid use disorder on postoperative outcomes including in-hospital mortality, hospital length of stay (LOS), hospital readmission, and postoperative complications in patients undergoing appendectomy or cholecystectomy.

METHODS

The authors used administrative data from the State Inpatient Databases of the Healthcare Cost and Utilization Project for the years 2007-2014 from California, Florida, Kentucky, Maryland, and New York. The authors compared unadjusted rates of in-hospital mortality, postoperative complications, LOS, and 30-day and 90-day readmission status. The authors calculated the adjusted odds ratio (OR) for their outcomes using logistic regression models.

RESULTS

In all, 488,981 appendectomy patients and 790,491 cholecystectomy patients aged ≥ 18 years were included in the analysis. Appendectomy (OR 2.26) but not cholecystectomy patients with opioid use disorder had statistically significant adjusted odds of in-hospital death. Patients with opioid use disorder (overall reported, and by each procedure separately) had higher adjusted odds of postoperative complication (OR 1.46), 30-day readmission (OR 1.80), 90-day readmission (OR 1.98), and longer LOS (OR 1.37).

CONCLUSIONS

The authors found higher unadjusted rates and adjusted ORs of in-patient mortality, hospital readmission, and postoperative complications in patients with opioid use disorder undergoing common abdominal surgeries. The authors' study shows that opioid use disorder is a risk factor for poorer postoperative outcomes in this surgical patient population.

Acute Pain Management/Regional Anesthesia

Effective and efficient acute pain management strategies have the potential to improve medical outcomes, enhance patient satisfaction, and reduce costs. Pain management records are having an increasing influence on patient choice of health care providers and will affect future financial reimbursement. Dedicated acute pain and regional anesthesia services are invaluable in improving acute pain management. In addition, nonpharmacologic and alternative therapies, as well as information technology, should be viewed as complimentary to traditional pharmacologic treatments commonly used in the management of acute pain. The use of innovative technologies to improve acute pain management may be worthwhile for health care institutions.

Breast Cancer Stem Cells and the Epithelial-Mesenchymal Transition

The acquisition of highly malignant traits by carcinoma cells is often associated with the activation of a transdifferentiation program termed the epithelial-mesenchymal transition (EMT). The EMT program is deployed in a variety of steps of embryonic morphogenesis, enabling the interconversion of epithelial and mesenchymal cell types. When both normal and neoplastic epithelial cells undergo an EMT, they acquire addition changes in addition to expressing characteristic mesenchymal cell markers. In particular, they acquire motility, an increased resistance to apoptosis and, in the case of carcinoma cells, invasiveness. The motility and invasiveness components associated with the EMT would appear to empower many types of cancer cells to metastasize. An interesting question is how the resulting disseminated cancer cells are able to spawn a macroscopic tumor mass at distant anatomical sites, since this clonal expansion would appear to require an ability to self-renew. Recently, we have examined the cellular products of an EMT. Contrary to our expectations, the resulting cells acquired many of the attributes of stem cells, including the expression of stem cell-associated cell-surface markers. Conversely, mammary epithelial cells that naturally express these markers also express greatly elevated levels of at least four pleiotropically acting transcription factors that have been found able to induce an EMT. More recent studies have confirmed that the product of an EMT in mouse mammary epithelial cells is a cell that has a greatly increased ability to generate an entire mammary ductal epithelial tree. Moreover, we find that cells with the attributes of stem cells exist naturally as minor subpopulations in cultured human mammary epithelial cells. These cells can differentiate spontaneously into non-stem cells and, conversely, the non-stem cells appear capable of dedifferentiating spontaneously into cells with progenitor or stem-cell phenotypes. Hence, the study of certain aspects of mammary epithelial cell biology, including the biology of mammary carcinoma stem cells, may be feasible with cultured cells.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr A1-1.

Biochemical and morphological characterization of an intracellular membrane compartment containing AMPA receptors

AMPA receptors cycle rapidly in and out of the postsynaptic membrane, while NMDA receptors are relatively immobile. Changing the distribution of AMPA receptors between intracellular and surface synaptic pools is an important means of controlling synaptic strength. However, little is known about the intracellular membrane compartments of neurons that contain AMPA receptors. Here we describe biochemical and morphological characteristics of an intracellular pool of AMPA receptors in rat brain. By velocity gradient centrifugation of microsomal light membranes from rat brain, we identified a membrane fraction enriched for AMPA receptor subunits GluR2/3 but lacking NMDA receptors. This membrane compartment sedimented more slowly than synaptosomes but faster than synaptic vesicles and cofractionated with GRIP, PICK-1 and syntaxin-13. Morphological examination of this fraction revealed round and tubular vesicles ranging from approximately 50 to 300 nm in diameter. Immunocytochemistry of cultured hippocampal neurons showed that a significant portion of AMPA receptors colocalized with syntaxin-13 (a SNARE protein associated with tubulovesicular recycling endosomes) and with transferrin receptors. Taken together, these results suggest that a pool of intracellular GluR2/3 resides in a syntaxin 13-positive tubulovesicular membrane compartment, which might serve as a reservoir for the dendritic recycling of AMPA receptors.

Is the oxidation of high-density lipoprotein lipids different than the oxidation of low-density lipoprotein lipids?

This article gives detailed insight into the kinetics of high-density lipoprotein (HDL) oxidation catalyzed by azobis(2-amidinopropane).dihydrochloride (ABAP) or by copper. ABAP initialized oxidation of human HDL 3-4 times faster than non-human primate HDL with a similar composition. The oxidizability of non-human primate HDL was 1000 times lower than the oxidizability calculated from rate constants derived from liposome oxidation, suggesting that there is a slow step in HDL oxidation not present in liposomes. Saturable binding of copper to HDL was a significant feature of copper-catalyzed oxidation. Binding constants (K(m)) for non-human primate HDL were 2-3-fold lower than those for human HDL. Copper-catalyzed oxidation of non-human primate HDL was slower than that of human HDL, but human HDL(2) and HDL(3) oxidized at about the same rate. Overall, the kinetics describing the oxidation of HDL were mechanistically similar to those reported for LDL, suggesting that HDL lipids were as easily oxidized as LDL lipids and that HDL will be easily oxidized in vivo when exposed to agents that oxidize LDL.

Cyclin D2 is essential for BCR-mediated proliferation and CD5 B cell development

Progression into G(1) in B lymphocytes is regulated by cyclins D2 and D3, components of the cell cycle machinery currently believed to have overlapping and potentially redundant roles in cell cycle control. To study the specific role of cyclin D2 in B lymphocyte proliferation, we examined B cells from cyclin D2(-/-) mice and demonstrate a specific requirement for cyclin D2 in BCR- but not CD40- or lipopolysaccharide-induced proliferation. Furthermore, conventional B cell development proceeds normally in the mutant mice; however, the CD5 B cell compartment is dramatically reduced, suggesting that cyclin D2 is important in CD5 B cell development as well as antigen-dependent B cell clonal expansion.

Association of AMPA receptors with a subset of glutamate receptor-interacting protein in vivo

The NMDA and AMPA classes of ionotropic glutamate receptors are concentrated at postsynaptic sites in excitatory synapses. NMDA receptors interact via their NR2 subunits with PSD-95/SAP90 family proteins, whereas AMPA receptors bind via their GluR2/3 subunits to glutamate receptor-interacting protein (GRIP), AMPA receptor-binding protein (ABP), and protein interacting with C kinase 1 (PICK1). We report here a novel cDNA (termed ABP-L/GRIP2) that is virtually identical to ABP except for additional GRIP-like sequences at the N-terminal and C-terminal ends. Like GRIP (which we now term GRIP1), ABP-L/GRIP2 contains a seventh PDZ domain at its C terminus. Using antibodies that recognize both these proteins, we examined the subcellular localization of GRIP1 and ABP-L/GRIP2 (collectively termed GRIP) and their biochemical association with AMPA receptors. Immunogold electron microscopy revealed the presence of GRIP at excitatory synapses and also at nonsynaptic membranes and within intracellular compartments. The association of native GRIP and AMPA receptors was confirmed biochemically by coimmunoprecipitation from rat brain extracts. A majority of detergent-extractable GluR2/3 was complexed with GRIP in the brain. However, only approximately half of GRIP was associated with AMPA receptors. Unexpectedly, immunocytochemistry of cultured hippocampal neurons and rat brain at the light microscopic level showed enrichment of GRIP in GABAergic neurons and in GABAergic nerve terminals. Thus GRIP is associated with inhibitory as well as excitatory synapses. Collectively, these findings support a role for GRIP in the synaptic anchoring of AMPA receptors but also suggest that GRIP has additional functions unrelated to the binding of AMPA receptors.

Bone maintenance 5 to 10 years after sinus grafting

PURPOSE

This radiographic study determined the amount of bone around hydroxyapatite (HA)-coated dental implants that were placed into bone-grafted maxillary sinuses.

PATIENTS AND METHODS

Postoperative complex motion tomograms using the Grossman technique were taken on 16 patients who had 27 maxillary sinus grafts performed using particulate autogenous iliac bone with and without demineralized bone, autogenous iliac corticocancellous block with and without demineralized bone, and autogenous jaw bone with demineralized bone. Bone levels were measured from the new floor of the grafted sinus to the apex of the implant and to the alveolar crest. The resulting bone level measures were compared with the type of graft used. All patients had been restored for 5 to 10 years after simultaneous graft and implant placement.

RESULTS

For all patients summed together, the average amount of bone from the top of the graft to the apex of the implant was 3.3 +/- 3.1 mm, and the average amount of bone from the top of the graft to the alveolar crest was 17.6 +/- 3.1 mm. The average level of bone in the sinuses of patients grafted with autogenous iliac bone was greater than the average level of bone in those grafted with autogenous bone combined with demineralized bone.

CONCLUSION

The results of this study indicate that autogenous bone grafts are maintained in the maxillary sinus, but the results with autogenous bone alone are better than when demineralized bone is added. However, this difference may not be clinically significant.

Differential regional expression and ultrastructural localization of alpha-actinin-2, a putative NMDA receptor-anchoring protein, in rat brain

Fast chemical neurotransmission is dependent on ionotropic receptors that are concentrated and immobilized at specific postsynaptic sites. The mechanisms of receptor clustering and anchoring in neuronal synapses are poorly understood but presumably involve molecular linkage of membrane receptor proteins to the postsynaptic cytoskeleton. Recently the actin-binding protein alpha-actinin-2 was shown to bind directly to the NMDA receptor subunits NR1 and NR2B (), suggesting that alpha-actinin-2 may function to attach NMDA receptors to the actin cytoskeleton. Here we show that alpha-actinin-2 is localized specifically in glutamatergic synapses in cultured hippocampal neurons. By immunogold electron microscopy, alpha-actinin-2 is concentrated over the postsynaptic density (PSD) of numerous asymmetric synapses where it colocalizes with NR1 immunoreactivity. Thus alpha-actinin-2 is appropriately positioned at the ultrastructural level to function as a postsynaptic-anchoring protein for NMDA receptors. alpha-Actinin-2 is not, however, exclusively found at the PSD; immunogold labeling was also associated with filaments and the spine apparatus of dendritic spines and with microtubules in dendritic shafts. alpha-Actinin-2 showed marked differential regional expression in rat brain. For instance, the protein is expressed at much higher levels in dentate gyrus than in area CA1 of the hippocampus. This differential regional expression implies that glutamatergic synapses in various parts of the brain differ with respect to their alpha-actinin-2 content and thus, potentially, the extent of possible interaction between alpha-actinin-2 and the NMDA receptor.

Iliac apophyseal cartilage augmentation of the deficient piriform rim and maxilla in alveolar cleft grafting

This article presents a new approach to cleft lip and cleft palate repair, where the retained bulk of alveolar cleft grafts is augmented by simultaneous cartilage augmentation of the deficient maxilla. Nine patients who provided 10 cleft sites underwent secondary bone grafting of the clefted alveolus by this technique. This study evaluates the following: (1) the postoperative esthetic results, (2) the quantity of bone in the grafted area, and (3) the provision of bone support for unerupted teeth, for teeth adjacent to the cleft, and for orthodontic tooth movement when the secondary bone grafting of the cleft is integrated with the onlay augmentation of the deficient maxilla. Photographic and radiographic investigations were undertaken. The photographic evaluation showed that all patients exhibited improved facial esthetics in the area of the cleft, particularly in the paranasal area of the maxilla; improved alar base support, symmetry of the columella, and less deviation of the tip of the nose were seen. The radiographic evaluation indicated the following: (1) the average percentage of the alveolar bone height of the grafted area was equal to 76% of the normal side; (2) nine canines erupted or were erupting through the grafted area; there were no adequate records to evaluate the fate of the remaining canine; (3) no teeth involved in the cleft area were ankylosed, because of inadequate records, so evaluators could not determine the status of one tooth; (4) all patients had adequate quantity of bone for orthodontic tooth movement through the grafted area; and (5) the periodontal support of the teeth involved in the cleft was adequate.

Film-screen systems: sensitometric comparison of Kodak Ektavision system to Kodak T-Mat/RA system

BACKGROUND

In 1995, Eastman Kodak Company (Rochester, N.Y.) marketed the Ektavision Extraoral Imaging Film and Screen System. It produced high-resolution images by keeping the light emitted by intensifying screens from "punching through" one emulsion layer on the film to another.

OBJECTIVES

The objectives of the experiment were (1) to compare the sensitometric properties of the Ektavision system to its predecessor, the T-Mat/RA system and (2) to determine whether films and screens of the Ektavision and the T-Mat/RA systems could be interchanged without clinically changing the sensitometric properties. Ektavision and Lanex Regular intensifying screens were used in combination with Ektavision, T-Mat G/RA, T-Mat L/RA, and T-Mat H/RA films.

RESULTS

The results showed that the Ektavision film was slightly slower than the T-Mat G/RA film no matter what type of screen was used. The type of screen used had little effect on inherent contrast or exposure latitude. The Ektavision film had approximately similar inherent contrast as the T-Mat G/RA film but less than that of the T-Mat H/RA film; its latitude was less than that of the T-Mat L/RA film. The manufacturer does not recommend combining T-Mat/RA film with Ektavision screens or Lanex Regular screens with Ektavision film because of a possible reduction in image resolution. But this mismatch did not clinically affect inherent contrast and exposure latitude; however, film speed was slightly affected.

CONCLUSIONS

The Ektavision system is the result of advanced technology that produces images of high resolution. The high-resolution Ektavision film is slightly slower than the T-Mat G/RA film but is equivalent to it in its contrast and latitude. Therefore when changing from the combination of T-Mat/RA film plus Lanex Regular screens to that of Ektavision film plus Ektavision screens, a slight increase in x-radiation exposure should be made.

Effects of tomographic motion, slice thickness, and object thickness on film density

The experiment used the computer-aided CommCat model IS 2000 tomographic machine (Imaging Sciences International, Roebling, N.J.). The objective of the experiment was to study the influence of tomographic tube motion, tomographic slice thickness, and object thickness on film density. The experiment was conducted by x-radiating an aluminum step-wedge placed along the x-axis. Exposures were made for different tube motions and for different slice thicknesses. In linear horizontal and linear vertical motions, an increased slice thickness decreased film density. Slice thickness had a stronger effect on film density when the object to be x-radiated was thinner. In circular, elliptical, spiral, and hypocycloidal motions, changes in slice thickness had no noticeable effect on film density because the manufacturer had programmed the machine to produce approximately similar exposure times by increasing the x-ray tube velocity thickness had a greater effect on film density for circular, elliptical, spiral, and hypocycloidal tube motions than for linear horizontal and linear vertical tube motions. Clinical observation showed that except for the linear vertical motion (motion that was oriented in the same direction as that of the tube travel) all other motions produced a zone of diffusion along the edges of the steps of the step-wedge. An increase in slice thickness had an effect on film density. Slice thickness had a noticeable effect on film density in linear but not in multidirectional tomography. Object thickness had a greater effect on film density in multidirectional than in linear tomography.

Effects of developer exhaustion on Kodak EKTASPEED Plus, Ektaspeed, and Ultra-speed dental films

In 1994, Eastman Kodak Co. (Rochester, N.Y.) replaced its Ektaspeed film with the EKTASPEED Plus film. The manufacturer claims that one of the advantages of the new film is that it is not strongly affected by exhausted (depleted plus aged) processing solutions. The objective of the experiment was to test this claim. In exhausted solutions, EKTASPEED Plus film lost its speed more rapidly than Ultra-speed film but less rapidly than Ektaspeed film; that is, Ultra-speed film had the most stable speed. EKTASPEED Plus film lost contrast for 2 weeks before stabilizing, whereas Ultra-speed and Ektaspeed films continued to lose contrast for 3 weeks. Overall, EKTASPEED Plus film held its contrast over the other two films. EKTASPEED Plus film stopped increasing its film latitude after 2 weeks, whereas Ultra-speed and Ektaspeed films continued to increase film latitudes. In conclusion, for the three films studied, EKTASPEED Plus maintained the most constant levels of contrast and latitude in progressively exhausted solutions. All three films lost speed in exhausted solutions; EKTASPEED Plus film was the fastest but Ultra-speed film had the most stable speed.

Sensitometric comparison of Kodak EKTASPEED Plus, Ektaspeed, and Ultra-speed Dental Films

In 1994, Eastman Kodak Co. (Rochester, N.Y.) marketed EKTASPEED Plus dental film to combine the advantages of the contrast of Ultra-speed film and the speed of Ektaspeed film. EKTASPEED Plus film uses T-Grain Emulsion technology similar to that used in the manufacture of the light-sensitive indirect exposure Kodak T-Mat film. This study compared the sensitometric properties of Ultra-speed, Ektaspeed, and EKTASEED Plus dental films. EKTASPEED Plus film was faster than Ektaspeed film at all film densities. Ektaspeed film became slower at higher densities and around a density of 1.9 became even slower than the Ultra-speed film. EKTASPEED Plus film had high inherent contrast and narrow exposure latitude similar to that of Ultra-speed film, whereas Ektaspeed film had low inherent contrast and wide exposure latitude. In conclusion, EKTASPEED Plus film had the advantages of the high contrast of Ultra-speed film and the high speed of Ektaspeed film. It maintained its high speed at high densities.

Information recall of younger and older skilled athletes: the role of display complexity, attentional resources and visual exposure duration

This study was concerned with the interactive role of experience of athletic skill with other relevant environmental variables (display complexity, attentional resources, exposure time of stimuli) on perception (recall) of structured handball game situations. Nineteen experienced (older) and 19 less experienced (younger) handball players were assigned randomly either to ball-bouncing (diverted attention) or to calm seated (focused attention) conditions. In each of the two conditions, the subjects were exposed to a total of 36 slides containing 2-3, 5-6 and 8-10 players. Eighteen slides were exposed for 0.5 s and 18 for 1.0 s. All the slides contained structured defence and offence situations. Recall scores were subjected to repeated-measures ANOVA using attention condition and age as between-subject factors and task complexity and exposure duration as within-subject factors. The results showed that the recall of less experienced players deteriorated more than the recall of more experienced players following exposure to complex displays (> or = 8 players) while engaging in a secondary task (bouncing). The findings suggest that research paradigms should be applied in the field of sport which share both ecological validity and a potential to discover the cognitive substrates underlying experience and age in skilled motor performance.

Characterization of a cleavage mutant of the measles virus fusion protein defective in syncytium formation

Membrane fusion caused by measles virus (MV) is a function of the fusion (F) protein. This process is essential for penetration into the host cell and subsequent initiation of the virus replicative cycle. The biological activity of the MV F protein is generated by endoproteolytic cleavage of a precursor protein (F0) into a large F1 subunit and a smaller F2 subunit held together by disulfide bonds. The cleavage site consists of a cluster of five basic amino acids (amino acids 108 to 112) within the predicted primary structure of the F protein. To investigate the role of the arginine residue at the carboxy terminus of the F2 subunit (arginine 112), site-directed mutagenesis was used to construct a cleavage mutant of the MV F protein in which this arginine residue was changed to a leucine residue. The mutated F gene, encoding four out of the five basic amino acids at the cleavage site, was inserted into the genome of vaccinia virus. The resulting recombinant virus was used to study expression of the mutant F protein in infected cells. Analysis of the Leu-112 mutant protein made in infected cells demonstrated that this single-amino-acid substitution resulted in a reduced rate of transport of the mutant protein to the cell surface, despite its efficient cleavage to yield F1 and F2 subunits. However, the electrophoretic mobilities of the Leu-112 polypeptides suggested that the protein was cleaved incorrectly. This aberrant cleavage appears to have abolished the ability of the F protein to cause syncytium formation. The data indicate that the arginine 112 residue is critical for the correct proteolytic cleavage that is required for the membrane fusion activity of the MV F protein.

Functional analysis of N-linked glycosylation mutants of the measles virus fusion protein synthesized by recombinant vaccinia virus vectors

The role of N-linked glycosylation in the biological activity of the measles virus (MV) fusion (F) protein was analyzed by expressing glycosylation mutants with recombinant vaccinia virus vectors. There are three potential N-linked glycosylation sites located on the F2 subunit polypeptide of MV F, at asparagine residues 29, 61, and 67. Each of the three potential glycosylation sites was mutated separately as well as in combination with the other sites. Expression of mutant proteins in mammalian cells showed that all three sites are used for the addition of N-linked oligosaccharides. Cell surface expression of mutant proteins was reduced by 50% relative to the wild-type level when glycosylation at either Asn-29 or Asn-61 was abolished. Despite the similar levels of cell surface expression, the Asn-29 and Asn-61 mutant proteins had different biological activities. While the Asn-61 mutant was capable of inducing syncytium formation, the Asn-29 mutant protein did not exhibit any significant cell fusion activity. Inactivation of the Asn-67 glycosylation site also reduced cell surface transport of mutant protein but had little effect on its ability to cause cell fusion. However, when the Asn-67 mutation was combined with mutations at either of the other two sites, cleavage-dependent activation, cell surface expression, and cell fusion activity were completely abolished. Our data show that the loss of N-linked oligosaccharides markedly impaired the proteolytic cleavage, stability, and biological activity of the MV F protein. The oligosaccharide side chains in MV F are thus essential for optimum conformation of the extracellular F2 subunit that is presumed to bind cellular membranes.