Peri-implant alveolar bone loss with respect to bone quality after use of the osteotome technique: results of a retrospective study

Knife-edge configurations or non space-maintaining defects of the alveolar ridge limit the indications for implant-prosthetic rehabilitation. If ridge expansion is required, bone splitting and bone spreading techniques may be applied. Summers introduced a modified approach for ridge expansion by osteotome technique. The principles of this nonablative implant bed preparation technique are lateral and apical bone relocation and condensation. The peri-implant alveolar bone loss after use of the osteotome technique was evaluated radiographically with respect to the bone quality in 22 patients with 22 implants. Differences between the alveolar crest and the implant shoulder in radiographs obtained immediately after implant insertion, after the end of unloaded healing period and after different periods of functional loading were calculated. The osteotome technique was used in bone quality classes 2 and 3, respectively, according to the Lekholm and Zarb classification. Two implants failed. Significant differences were found between the bone levels after implant insertion and at the end of the healing period as well as after functional loading (P = 0.028). The bone quality was significantly correlated (r = - 0.505; P = 0.023) with the change of the peri-implant marginal bone height level 6 months after the implant installation. The present data indicate the importance of bone quality evaluation before application of the osteotome technique.     

Arteriolar and venular patterning in retinas of mice selectively expressing VEGF isoforms

The murine VEGF gene is alternatively transcribed to yield the VEGF(120), VEGF(164), and VEGF(188) isoforms, which differ in their potential to bind to heparan sulfate and neuropilin-1 and to stimulate endothelial growth. Here, their role in retinal vascular development was studied in mice selectively expressing single isoforms. VEGF(164/164) mice were normal, healthy, and had normal retinal angiogenesis. In contrast, VEGF(120/120) mice exhibited severe defects in vascular outgrowth and patterning, whereas VEGF(188/188) mice displayed normal venular outgrowth but impaired arterial development. It is noteworthy that neuropilin-1, a receptor for VEGF(164), was predominantly expressed in retinal arterioles. These findings reveal distinct roles of the various VEGF isoforms in vascular patterning and arterial development in the retina.     

Strength response in human femoris muscle during 2 neuromuscular electrical stimulation programs

STUDY DESIGN: Experimental mixed repeated-measures design. OBJECTIVE: To determine the effect of 2 versus 3 neuromuscular electrical stimulation (NMES) training sessions per week on the response to strength training of the quadriceps femoris muscle. BACKGROUND: Many studies have examined the influence of training intensity (percent maximal voluntary isometric contraction [MVIC]) during NMES on the strength response of the quadriceps femoris muscle. However, no study has examined the effects of the number of NMES sessions per week on the change in strength of the quadriceps femoris. METHODS AND MEASURES: Twenty-seven healthy subjects (mean age +/- SD, 23.2 +/- 3.2 years) volunteered for the study and were randomly assigned to 1 of 3 groups; control group (no electrical stimulation); group 2 (NMES 2 times per week); and group 3 (NMES 3 times per week). Groups 2 and 3 received NMES (10 minutes per session) over a 4-week period for a total of 8 and 12 NMES training sessions, respectively. The isometric quadriceps femoris muscle force produced during NMES was monitored during each treatment minute. The MVIC force of the quadriceps femoris was assessed prior to the first week and at the start of weeks 2, 3, and 4 of the 4-week training program, with a final measurement after the fourth week (5 total measurements) for all subjects. RESULTS: Only the mean percent change in quadriceps MVIC before and after the 4 weeks of training with NMES between the control group and group 3 was significantly different (P = .021). CONCLUSIONS: Based on the electrical stimulation parameters and healthy subjects used in this study, NMES caused significant increases in the quadriceps femoris muscle strength when used for 3 training sessions per week for 4 weeks. It is possible that the use of a different electrical stimulation paradigm and/or a different patient population may result in strength gains with 1 or 2 sessions per week.     

Aneurysmal Degeneration of the Superficial Femoral Artery following Stenting: An Uncommon Infectious Complication

Infrainguinal angioplasty and stenting is becoming a more commonly performed procedure. Its durability remains a matter of debate, however. Aneurysmal degeneration following angioplasty and stenting is a complication not previously described in the literature with regard to the superficial femoral artery. We present a case in which two aneurysms of the superficial femoral artery developed following angioplasty and multiple-stent placements in a patient who had previously undergone a failed femoral-to-below-the-knee popliteal artery PTFE bypass graft. The patient presented to our institution with an occluded, infected bypass graft. He was treated with graft and femoral artery/stent excision and vein bypass grafting. A brief review of infectious complications after stent placement is included.     

Complement activation following optic nerve crush in the adult rat

Activation of the complement cascade following peripheral nerve axotomy and following traumatic brain injury has been demonstrated in previous studies. This study investigates the temporal pattern of microglia/macrophages and complement activation following axotomy of sensory CNS neurons, using a standardized experimental crush injury of the optic nerve in adult rats. Numerous ED1-labeled macrophages were found at the lesion site and distal to the injury at 7 days post injury (dpi). Complement C3-mRNA was upregulated 2-28 days post lesion, indicating local synthesis of complement in the optic nerve. Furthermore, increased immunoreactivity (IR) for the end product of the complement cascade, the membrane attack complex (MAC), was detected along disintegrating axons co-labeled with anti-neurofilament distal to the injury. Double-labeling for microglia show MAC-immunoreactivity expressed in their immediate vicinity, indicating a key role of microglia/macrophages in complement activation. The complement regulator Clusterin was upregulated in astrocytes at the lesion site as well as in the distal portion of the injured optic nerve, suggesting activation of a defense response to endogenous complement attack. A crush injury of the optic nerve leads to complement activation at the site of lesion and along the distal portion of the nerve, as well as upregulation of the complement inhibitor Clusterin at least in astrocytes. Reactive microglial cells seem to have a key role in complement activation as a local source of C3. We suggest that the balance between complement activation and their regulators may have impact on axonal degeneration following optic nerve injury.     

US as a primary diagnostic tool in relation to negative appendectomy: six years experience

PURPOSE: To evaluate the effect of ultrasonography (US) on the rate of appendectomy after false-positive diagnosis of acute appendicitis (negative appendectomy). MATERIALS AND METHODS: Data were analyzed in 736 pediatric patients (mean age, 13.2 years) who had undergone appendectomy between 1995 and 2000. Histologic data were compared in patients who underwent US with those who did not undergo imaging prior to surgery. US was performed by a radiologist or a pediatric surgeon or both. RESULTS: A total of 643 (87.4%) of the 736 pediatric patients underwent preoperative US, and 93 (12.6%) of the 736 did not undergo preoperative US. Of the 736 patients, 97 (13.2%) underwent negative appendectomy. Thirty-four (36.6%) of the 93 patients who underwent appendectomy with no preoperative US and 63 (9.8%) of the 643 patients who underwent preoperative US underwent negative appendectomy. There was a significant association between US and positive appendectomy (P <.001). CONCLUSION: US in pediatric patients suspected of having appendicitis can significantly lower the negative appendectomy rate.     

Sensitivity encoding for fast MR imaging of the brain in patients with stroke

PURPOSE: To evaluate sensitivity encoding (SENSE) technique in a clinical setting for magnetic resonance (MR) imaging in patients who are suspected of having infarction. MATERIALS AND METHODS: This intraindividual comparative study included 62 patients suspected of having cerebral ischemia. Patients underwent T2-weighted fluid-attenuated inversion-recovery (FLAIR) (n = 62), T2-weighted turbo spin-echo (TSE) (n = 48), and single-shot echo-planar diffusion-weighted imaging (n = 27) with standard sequential and SENSE MR acquisitions with a 1.5-T magnet and phased-array coil. With SENSE, acquisition time was reduced from 1 minute 12 seconds to 35 seconds for FLAIR and from 1 minute 18 seconds to 39 seconds for T2-weighted TSE imaging. For diffusion-weighted imaging, echo train length was shortened (78 vs 71 msec) to reduce susceptibility effects while acquisition time was maintained. Two radiologists scored quality of standard and SENSE images with a five-point scale and assessed presence of artifacts (motion, susceptibility) and lesion conspicuity. To assess statistical significance, Wilcoxon signed rank and chi2 tests were used. RESULTS: Statistical analysis revealed no significant difference in terms of image quality and presence of artifacts between standard and SENSE T2-weighted TSE (image quality, P =.724; presence of artifacts, P =.378) and FLAIR (image quality, P =.127; presence of artifacts, P =.275) images. Image quality at SENSE diffusion-weighted imaging was scored significantly higher compared with that at standard diffusion-weighted imaging (P =.002). Susceptibility artifacts were significantly reduced at SENSE diffusion-weighted imaging when compared with those at standard diffusion-weighted imaging (P <.001). Conspicuity of 84 lesions was rated equivalent with both standard and SENSE protocols. CONCLUSION: SENSE allowed acquisition of T2-weighted TSE and FLAIR images with image quality and lesion conspicuity that did not differ from those of standard acquisition techniques but in only half the acquisition time. Use of SENSE with diffusion-weighted imaging significantly reduces susceptibility artifacts while lesion conspicuity is maintained.     

Impact of bispectral index monitoring on fast tracking of gynecologic patients undergoing laparoscopic surgery

BACKGROUND: The need for increasing operating room efficiency has led to various initiatives, one of which is the elimination of mandatory admission to the phase I recovery area postoperatively, also referred to as fast tracking of ambulatory surgery patients. This Institutional Review Board-approved study was conducted to evaluate the effect of Bispectral Index (BIS) monitoring on the ability of patients to successfully bypass the phase I recovery area following gynecologic laparoscopy during general anesthesia. METHODS: Ninety-nine consenting patients were randomly assigned to one of two groups: group one, in which the BIS monitor (Aspect Medical Systems, Natick, MA) was used, and group two, in which no BIS monitor was used. All patients received a standardized anesthetic that included 1 microg/kg sufentanil and sevoflurane in oxygen, titrated in group one to a BIS value of 50-60 and in group two to maintain vital signs within 20% of preoperative values. All patients received prophylactic nonsteroidal antiinflammatory drugs and antiemetics. Postoperatively, patients were evaluated using the modified Aldrete scoring system, and those who achieved a score of 9 or higher within 10 min were permitted to bypass the phase I recovery area. RESULTS: There was no statistically significant difference between the two groups with respect to the number of patients who successfully bypassed the phase I recovery area, postoperative length of hospital stay, or cost of hospitalization. CONCLUSION: With a standardized anesthetic regimen and a strict discharge scoring system, BIS monitoring does not have a significant effect on the ability to fast track outpatients.     

Effects of antidepressants on function and viability of human neutrophils

BACKGROUND: Antidepressants are frequently used in chronic pain therapy and are under investigation as long-acting local anesthetics. Because of the structural similarities between antidepressants and local anesthetics, the authors hypothesized that these compounds act similarly, and they investigated the effects of nortriptyline, amitriptyline, imipramine, and fluoxetine on priming and activation of human polymorphonuclear neutrophils (hPMNs). METHODS: Effects of 30-, 120-, and 240-min preincubation with nortriptyline (10(-7)-10(-4) M), amitriptyline (10(-6)-10(-3) M), imipramine (10(-6)-10(-3) M), or fluoxetine (10(-7)-10(-4) M) on O(2)- generation of platelet activating factor-primed (10-6 M) and/or formyl-methionyl-leucyl-phenylalanine-activated (10(-6) M) isolated hPMNs were determined. All data are reported as mean +/- SD (statistics: t test, P < 0.05). RESULTS: Brief incubation in low concentrations of nortriptyline, amitriptyline, or fluoxetine (all at 10(-5) M) did inhibit priming but not activation of hPMNs. Imipramine (10(-5) M) affected neither priming nor activation. Prolonged incubation in lower concentrations of all antidepressants influenced neither priming nor activation. However, at higher concentrations, all four compounds exerted cytotoxic effects: virtually all hPMNs were killed by amitriptyline and imipramine (both at 10(-3) M) or nortriptyline and fluoxetine (both at 10(-4) M). CONCLUSION: Antidepressants, in low concentrations, inhibited priming but not activation of hPMNs. However, at concentrations similar to those attained after local injection, and in marked contrast to local anesthetics, antidepressants are profoundly toxic to hPMNs.     

Redistribution of microcirculatory blood flow within the intestinal wall during sepsis and general anesthesia

BACKGROUND: Hypoperfusion of the intestinal mucosa remains an important clinical problem during sepsis. Impairment of the autoregulation of microcirculatory blood flow in the intestinal tract has been suggested to play an important role in the development of multiple organ failure during sepsis and surgery. The authors studied microcirculatory blood flow in the gastrointestinal tract in anesthetized subjects during early septic shock. METHODS: Eighteen pigs were intravenously anesthetized and mechanically ventilated. Regional blood flow in the superior mesenteric artery was measured with ultrasound transit time flowmetry. Microcirculatory blood flow was continuously measured with a six-channel laser Doppler flowmetry system in the mucosa and the muscularis of the stomach, jejunum, and colon. Eleven pigs were assigned to the sepsis group, while seven animal served as sham controls. Sepsis was induced with fecal peritonitis, and intravenous fluids were administered after 240 min of sepsis to alter hypodynamic sepsis to hyperdynamic sepsis. RESULTS: In the control group, all monitored flow data remained stable throughout the study. During the hypodynamic phase of sepsis, cardiac output, superior mesenteric artery flow, and microcirculatory blood flow in the gastric mucosa decreased by 45%, 51%, and 40%, respectively, compared to baseline (P < 0.01 in all). Microcirculatory blood flow in the muscularis of the stomach, jejunum, and colon decreased by 55%, 64%, and 70%, respectively (P < 0.001 in all). In contrast, flow in the jejunal and colonic mucosa remained virtually unchanged. During the hyperdynamic phase of sepsis, there was a threefold increase in cardiac output and superior mesenteric artery flow. Blood flow in the gastric, jejunal, and colonic mucosa also increased (22%, 24%, and 31% above baseline, respectively). Flow in the muscularis of the stomach returned to baseline, while in the jejunum and colon, flow in the muscularis remained significantly below baseline (55% and 45%, respectively, P< 0.01). CONCLUSIONS: It appears that in early septic shock, autoregulation of microcirculatory blood flow is largely intact in the intestinal mucosa in anesthetized pigs, explaining why microcirculatory blood flow remained virtually unchanged. This may be facilitated through redistribution of flow within the intestinal wall, from the muscularis toward the mucosa.