Horizontal Ridge Reconstruction of Atrophic Anterior Maxillary Ridges Using Customized Xenograft Bone Shell with 1:1 Mixture of Autogenous and Xenograft Bone Particulate (A Case Series Study).

INTRODUCTION: Different surgical procedures have been proposed to achieve successful horizontal ridge reconstruction of the anterior maxilla, most of these procedures require complex surgical stages with morbidity and are time-consuming. AIM: The purpose of this study is to evaluate the efficacy of using a customized xenograft shell with a 1:1 mixture of particulates xenograft and autogenous bone for the reconstruction of horizontally deficient anterior maxillary alveolar ridges. METHODS: Cone beam computed tomography (CBCT) images of the atrophic maxilla of eight patients were acquired and generated into 3D models. The data were transferred to a 3D printer and solid models were fabricated. During the surgery, the xenograft blocks were manually sliced and customized on the 3D printed models and fixed then the gap was augmented with a 1:1 xenograft autograft mixture. RESULTS: Clinical assessment showed no adverse effects. However, one patient exhibited wound dehiscence. The mean difference between the preoperative and the six months postoperative showed a net average bone gain by 4.06 mm at 2 mm from the crest and 4.34 mm at 5 mm from the crest, which was statistically significant. On the other hand, a statistically significant graft resorption by 1.41 mm and 2.19 mm at 2 and 5 mm from the crest was found when the mean difference between the immediate and the six months postoperative was calculated. CONCLUSIONS: Within the limitations of the study, the use of xenograft shells as a barrier for maxillary alveolar ridge reconstruction is predictable technique however, further investigations regarding the required time for graft consolidation is required.

Assessment of absorbable gelatin sponge for maxillary sinus floor elevation versus anorganic bovine bone minerals: a randomized clinical trial.

PURPOSE: The present study compared the absorbable gelatin sponge as a space-filling material versus anorganic bone bovine mineral (ABBM) in maxillary sinus augmentation with simultaneous endosseous dental implant placement. METHODS: Eighteen maxillary sinus floor elevation cases were randomly allocated into two groups. The first group received ABBM, while the second group received an absorbable gelatin sponge as a space-filling material. For both groups, CBCT scans were obtained immediately postoperatively and six months later to calculate the difference in sinus floor bone gain. Osstell readings were recorded both at the time of implant placement and implant exposure with a total of twenty-three dental implant placements in relation to the eighteen elevated sinus floors. RESULTS: The mean radiographic sinus floor gain in the ABBM group was 10.2 mm (± 2.5), while in the absorbable gelatin sponge group was 5.4 mm (± 2.0), with a mean difference of 4.8, which was statistically significant (p < 0.001). The mean implant stability for the ABBM was 77.3 (± 4.9), while in the absorbable gelatin sponge group was 74.2 (± 3.0), with a mean difference of 3.1, which was statistically insignificant (p = 0.1610). CONCLUSION: The ABBM showed superior results regarding the amount of radiographic sinus floor bone gain. However, the implant stability was invariable between both groups.

Guided Bone Regeneration for Horizontal Maxillary Alveolar Ridge Augmentation Using Patient-Specific Solid Titanium Barriers: A Case Series

PURPOSE: To assess the radiographic and histomorphometric outcomes of horizontally augmented maxillary alveolar ridges using solid nonperforated customized titanium barriers. MATERIALS AND METHODS: This case series study included patients who received guided bone regeneration treatment in the anterior maxillary esthetic zone (eight patients, 18 dental implants) using patient-specific solid titanium barriers loaded with a mix of autogenous and xenogenic particulate bone grafts. A radiographic comparison between three time periods (immediately postoperative, 4 months, and 10 months) included software-aided calibration of the linear changes in the horizontal dimensions on CBCT cross-sectional cuts after being standardized. Bone core specimens were retrieved for histomorphometric analysis by the time of implant insertion. RESULTS: Wound healing was uneventful, except for two patients who showed soft tissue breakdown that did not affect the outcome. There was a statistically significant difference between the mean horizontal bone change at the different time intervals (P < .001), with a 79.6% ± 29.2% mean area of newly formed bone. CONCLUSION: GBR using customized solid titanium barriers appears to be efficient and promising concerning the final horizontal bone gain and the quality of the augmented sites.

Cavernous Sinus Thrombosis and Blindness After Simple Tooth Extraction in Patient Who Recovered From Coronavirus 2019: A Case Report.

The pandemic Coronavirus 2019 is a disease transmitted either by droplets from a person's sneeze or cough or direct spread; also known as severe acute respiratory syndrome coronavirus-2. Although the morbidity of the disease is mainly related to respiratory distress, the associated inflammatory response can induce various coagulopathies despite an anticoagulant therapy. The authors are documenting a case of a diabetic patient who recovered from Coronavirus 2019 and is on prophylactic anticoagulant therapy after routine extraction of a maxillary second molar that progressed to unilateral cavernous sinus thrombosis and loss of vision.

Polyetheretherketone patient-specific implants (PPSI) for the reconstruction of two different mandibular contour deformities.

BACKGROUND: This study aims to prospect the soft and hard tissue changes after augmentation of two different local mandibular contour defects using polyetheretherketone (PEEK) patient-specific onlay implants. METHODS: Six patients with disfiguring local mandibular deformities were included in this study (five males and one female) and received seven PEEK patient-specific implants (PSI), virtually designed and surgically settled to augment seven mandibular defects, three deficient chins, and four mandibular angels. The analysis of the soft and hard tissue changes utilized the superimposition of the preoperative and the 6-month postoperative sagittal and coronal CT views, after standardizing the radiographic interpretation. RESULTS: The soft tissue gain for the chin was 6.8 mm ± 0.98 with a 45.8% increase versus 4.42 mm ± 0.41 with a 22.9% increase for the angle. The difference in the soft tissue gain between the two groups was statistically significant (P = 0.0001). Comparing the soft tissue gain to the planned implant thickness, the percentage of the soft tissue gain for the chin recorded 109.2% versus 65.57% for the angle. The difference between the two groups was also statistically significant (P < 0.0001). CONCLUSION: PEEK patient-specific onlay implants represented an efficient and straightforward modality to augment local mandibular contour deformities with favorable esthetic outcomes; the total soft tissue profile gain of the chin region markedly exceeded that of the mandibular angle.

An in vitro / in vivo release test of risedronate drug loaded nano-bioactive glass composite scaffolds.

Three-dimensional (3D) matrices scaffolds play a noteworthy role in promoting cell generation and propagation. In this study, scaffolds prepared from chitosan/polyvinyl alcohol loaded with/without an osteoporotic drug (risedronate) and nano-bioactive glass (nBG) have been developed to promote healing of bone defects. The scaffolds were characterized by scanning electron microscopy (SEM), porosity test as well as mechanical strength. The pattern of drug release and ability to promote the proliferation of Saos-2osteosarcoma cells had also been reported. Osteogenic potential of the scaffolds was evaluated by testing their effect on healing critical-sized dog's mandibular bone defects. Increasing chitosan and nBG in the porous scaffolds induced decrease in drug release, increased the scaffold's strength and supported their cell proliferation, alkaline phosphatase (ALP) activities, as well as increased calcium deposition. Histological and histomorphometric results demonstrated newly formed bone trabeculae inside critical-sized mandibular defects when treated with scaffolds. Trabecular thickness, bone volume/tissue volume and the percentage of mature collagen fibers increased in groups treated with scaffolds loaded with 10% nBG and risedronate or loaded with 30% nBG with/without risedronate compared with those treated with non-loaded scaffolds and empty control groups. These findings confirmed the potential osteogenic activity of chitosan/polyvinyl alcohol-based scaffolds loaded with risedronate and nBG.

Evaluation of the effect of the lateralized inferior alveolar nerve isolation and bone grafting on the nerve function and implant stability. (Randomized Clinical Trial).

BACKGROUND: The inferior alveolar nerve lateralization (IANL), although allows for an implant full-length mandibular height engagement, coincides with depleting the buccal bone support and sensory deficits. PURPOSE: This study aims to assess whether interposing a bone graft coupled with securing a collagen membrane separation between the inferior alveolar nerve (IAN) and the underlying dental implants would preserve the nerve function, enhance the implant stability, and minimize the radiographic marginal bone loss. MATERIAL AND METHODS: Eighteen patients with 30 atrophic mandibular edentulous ridges were subjected to IANL after being randomly assigned to two treatment modalities which consisted of 15 patients each. The (control group) utilized conventional IANL in direct contact with 20 implants. The (test group) implemented the IAN collagen-membrane wrapping and interposing bone graft to overlay 23 implants. The neural function, the radiographic marginal bone loss, and the implant stability quotient were assessed and compared 6 months postoperatively. RESULTS: All the patients regained their full neurosensory function after 6 months, with statistically nonsignificant differences between both groups throughout the follow-up period. The mean marginal bone loss in the test group was (0.42 ± 0.09) mm versus (0.38 ± 0.14) mm for the control group, which was statistically similar (P = 0.401). The 6-month postoperative mean implant stability quotient values of the test group recorded (74.73 ± 2.68) versus (74.73 ± 1.79) for the control group, which was statistically nonsignificant with a value of P = 0.626. CONCLUSION: The interposed bone graft, coupled with the collagen membrane isolation, neither subsided the neural disturbances nor enhanced the secondary implant stability and marginal bone loss.

The assessment of the effect of the size of lateral-antrostomy in graftless balloon elevation of the maxillary sinus membrane with simultaneous implant placement (a randomized controlled clinical trial).

BACKGROUND: The overlying maxillary sinus frequently restrains the height of the posterior maxillary bones. PURPOSE: Evaluating the effect of downsizing the antrostomy side-window on the stability of the installed implants and vertical bone gain, after employing a graftless antral membrane balloon elevation (AMBE). MATERIALS AND METHODS: The study is a randomized controlled clinical trial conducted on 20 patients with 30 deficient maxillary alveolar ridges underwent graftless (AMBE) after being allocated into a (5 mm) entry antrostomy group (the test group) and a (10 mm) entry antrostomy group (the control group) implementing a radiographic linear bone height and implant stability quotations (ISQ) comparison among both groups immediately after the placement of 38 Implants and 6 months after. RESULTS: Radiographic bone gain of the test group (5.55 ± 0.93 mm) was significantly higher than the control group (2.86 ± 0.60 mm) (p <0.001). There was no significant difference in primary stability between the test (65 ± 5.32) and control groups (62.67 ± 4.46) (p = 0.202); while the test group (73.43 ± 4.39) showed significantly higher secondary stability than the control group (64.83 ± 6.05) (p <0.001). ISQ values recorded at 6 months were significantly higher than those recorded at insertion in the test group (p <0.001), while they were insignificant in the control group (p = 0.148). CONCLUSION: Undersizing the antrostomy window deemed beneficial concerning the vertical bone gain and the simultaneously placed root form dental implants' secondary stability.

Assessment of bone quality using buccal and palatal autogenous cortical shells harvested from two different mandibular donor sites for maxillary alveolar ridge augmentation: a histomorphometric randomized clinical trial.

PURPOSE: This study aims to compare the quality of free autogenous bone grafts harvested from two different mandibular donor sites, used as onlay shells to augment horizontally and vertically deficient anterior maxillary alveolar ridges. METHODS: Fourteen patients with edentulous and atrophic anterior maxillae are randomly allocated into two groups. Seven symphyseal chin (group I) and seven retromolar (group II) mandibular bone grafts were harvested and fashioned to construct buccal and palatal frameworks, fixed in place with mini-screws, followed by compacting the inter-positional gaps with an equal particulate mix of xenograft and autogenous cancellous particulates. Six months later, 42 core biopsies, three from each patient, 21 for each study group, were retrieved before the implants' insertion and subjected to histomorphometric bone area percent analysis. RESULTS: The bone area percent of the newly formed bone augmented with the chin shells was 52.53 ± 1.68% versus 47.97 ± 1.83% for the retromolar grafts. The mean area percent difference between both groups was statistically significant (p = 0.0004). CONCLUSION: A higher bone quality and more volumetric stability were associated with the symphyseal cortical shells. CLINICAL TRIAL REGISTRATION: The study was registered on www.clinicaltrials.gov (#: NCT03607006) in July 2018 by Ola Alaa El Morsy.

Full-staged digital and prosthetic guided protocol for the insertion of dental implants in autogenous free bone grafts after reconstruction of segmental mandibular defects.

PURPOSE: This study aims to evaluate the clinical and radiographic outcomes of dental implants, inserted in consolidated free bone grafts; postsegmental mandibular resection, after following a fully guided staged protocol, which established a systematic approach that correlates the grafted bone and the enclosed implants to the undisturbed mandibular segments and the maxillary occlusal plane. METHODS: Seven patients were enrolled in the study; all were diagnosed for mandibular locally aggressive tumors. All of the patients were subjected to computer-guided segmental mandibular resections, secondary free iliac crest bone graft; aided by computer-guided harvest and prosthetic guidance of the graft positioning and fixation. Finally, the guided bone grafts; after being consolidated, received twenty-nine computer-guided dental implants. RESULTS: By the end of the period of osseointegration, the predetermined criteria of implant success judged the success of twenty-five implants, versus the failure of four implants, with (86.2%) percentage of success. CONCLUSION: The clinical and radiographic assessments demonstrated sound base bone grafts, which succeeded not only to restore the native mandibular continuity and configuration but also to direct the fair-sized embedded dental implants into favorable coastal locations and axial projections, which influenced a smooth prosthetic rehabilitation.

Computer-Guided Arthrocentesis Using Patient-Specific Guides: A Novel Protocol for Treatment of Internal Derangement of the Temporomandibular Joint.

PURPOSE: The aim of the present study was to evaluate the accuracy of 3-dimensionally (3D) printed patient-specific guides (PSGs) to direct the passage of inlet and outlet needles into the superior joint spaces of the temporomandibular joint (TMJ) in preparation for arthrocentesis. PATIENTS AND METHODS: The present study included 10 patients with 14 TMJs with anterior disc displacement with reduction. A 3D PSG was designed for each patient to lead the inlet and outlet needles into the superior joint space of the TMJ. The PSGs were implemented, and their accuracy for guiding the needles into the superior joint space was assessed. RESULTS: Both arthroscopic verification and clinical evaluation revealed that direct access to all the predetermined anatomic locations inside the TMJs had been obtained, except for 1 case, during which the patient had failed to maintain the maximum mouth opening during computed tomography scanning. CONCLUSIONS: The virtual computer-initiated PSGs were beneficial for directing the passage of the needles into the superior joint space.

Operative management of non-iatrogenic pediatric and adolescence peripheral arterial trauma: An experience from a resource challenged setting.

OBJECTIVES: To evaluates the management and outcome of non-iatrogenic pediatric and adolescence extremity arterial injuries in a resource-challenged setting. METHODS: A retrospective study of the surgical management for non-iatrogenic extremity arterial trauma in pediatric and adolescence during the period from January 2008 to December 2015. This study was performed in two different countries at tertiary referral university and teaching hospitals having a specialized emergency and trauma centers. A thorough study of each patient record was collected from these centers including, the original demographic data and their clinical presentations. Operative data of each patient was also reported. RESULTS: During the 8-year period of the study, 149 pediatric and adolescent extremity arterial trauma patients were treated. They were 93.3% male, and 6.7% female, respectively. The age ranged from 2 to 18 years with a mean of 10.25 ± 4.05 years. Lower extremity arterial trauma was recorded in 51%, while 49% were having upper extremity injuries. Primary repair with end-to-end vascular anastomosis was performed in 51.7%, while an interposition reversed saphenous vein graft was performed in 48.3%. The operative procedures were performed by an experienced vascular surgeon and well-trained pediatric surgeons and general surgeons. Pseudoaneurysms was recorded in 9% of cases. Fasciotomy was performed in 15% of cases. CONCLUSION: Treatment of pediatric and adolescent extremity arterial injuries with primary end-to-end vascular anastomoses or with the use of an interposition reversed saphenous vein graft is a reliable, feasible, and more cost-effectiveness technique with good results. Moreover, it should be adopted for all vascular trauma patients, whenever possible.

Management of Extremity Venous Thrombosis in Neonates and Infants: An Experience From a Resource Challenged Setting.

We aimed to evaluate the outcome of different treatment modalities for extremity venous thrombosis (VT) in neonates and infants, highlighting the current debate on their best tool of management. This retrospective study took place over a 9-year period from January 2009 to December 2017. All treated patients were referred to the vascular and pediatric surgery departments from the neonatal intensive care unit. All patients underwent a thorough history-taking as well as general clinical and local examination of the affected limb. Patients were divided into 2 groups: group I included those who underwent a conservative treated with the sole administration of unfractionated heparin (UFH), whereas group II included those who were treated with UFH plus warfarin. Sixty-three patients were included in this study. They were 36 males and 27 females. Their age ranged from 3 to 302 days. Forty-one (65%) patients had VT in the upper limb, whereas the remaining 22 (35%) had lower extremity VT. The success rate of the nonsurgical treatment was accomplished in 81% of patients. The remaining 19% underwent limb severing, due to established gangrene. The Kaplan-Meier survival method revealed a highly significant increase in both mean and median survival times in those groups treated with heparin and warfarin compared to heparin-only group ( P < .001). Nonoperative treatment with anticoagulation or observation (ie, wait-and-see policy) alone may be an easily applicable, effective, and a safe modality for management of VT in neonates and infants, especially in developing countries with poor or highly challenged resource settings.

Laparoscopy as a Primary Investigatory Tool in Pediatric Abdominal Masses.

BACKGROUND: Management of abdominal masses still pose a major challenge for pediatrician and surgeons with many controversy as regards the best investigatory tools. AIM OF THE WORK: This study was designated to evaluate the role of diagnostic laparoscopy in investigating equivocal pediatric masses that had undergone other imaging modalities. PATIENTS AND METHODS: A combined prospective and retrospective multicenter study over a period of 12 years from January 2005 to December 2016 was undertaken. This study included all children aged from 3 months to 15 years. Those having a documented diagnosis through other imaging modalities such as sonographic and/or computed tomography (CT) guided biopsy were excluded. All patients underwent multiport diagnostic laparoscopy for biopsy of the mass. All specimens were histologically assessed basically using Hematoxylin and Eosin (H and E) staining; some specimens had been immunohistochemically studied. RESULTS: One hundred and thirty-two patients were recruited in the study. They were 69 males and 63 females with a male to female ratio of1.1:1. The age ranged from 3 months up to 15 years with the mean age of 2.7 ± 0.8 years. Out of the total studied group, 54 patients were diagnosed with neuroblastoma (40.9%), while 66 (50%) were having nephroblastoma. The remaining 12 (9.1%) were having non-Hodgkin's abdominal lymphoma. Not all patients showed any complication related to the procedure. The mean follow up period was 3.6 years. Most of the cases (n=121) despite having a different diagnosis, were clinically staged as grade I to grade II (91.7%). Neither intraoperative nor postoperative complications were recorded during this technique. The mean operative time was 72 mins ± 20 in the earliest group; yet, it has declined to be 32 ± 12 minutes in the latest group due to the advancement of the learning curve. CONCLUSION: Laparoscopy is accurate and safe for investigating pediatric solid abdominal masses. It should be used as the sole tool for biopsy of solid abdominal tumors in pediatrics.

Reliability of sonoelastography in predicting pediatric cervical lymph node malignancy.

PURPOSE: Controversy exists as regards the best non-invasive diagnostic tool for pediatric cervical lymphadenopathy. The current work aimed to evaluate the reliability, sensitivity, specificity, and accuracy of sonoelastography in diagnosing benign and/or malignant pediatric cervical lymphadenopathy. METHODS: Prospective study took place over a period of 4 years from January 2013 to December 2016. A total of 177 lymph nodes (LNs) in 128 children with an age ranging from 11 months to 12 years were recruited in this study. Patients were 77 males and 51 females with a ratio of 3:2. All patients underwent a thorough history taking and clinical examination of the neck focusing on the cervical lymph nodes. After that, a B-mode sonography, Color Doppler ultrasound, and Sonoelastography were performed. Elastographic patterns of 1-5 were evaluated, whereas patterns of 3-5 (firm to hard) were suspected to have a malignant nature. Sonographic-guided aspiration cytology took place in 107 lymph nodes and excisional biopsy in 102 lymph nodes, whereas 13 lymph nodes responded adequately to conservative treatment. They proved to be benign reactive hyperplasia. RESULTS: The majority of LNs (87%) were of the malignant type that showed an elastographic pattern of 3-5. The same patterns were observed in only 6 (3.4%) of the benign LNs. Sonoelastography showed a sensitivity of 85.9%, specificity of 100%, PPV of 100%, NPV of 75.96%, and overall accuracy of 90.23% in distinguishing benign from malignant lymph nodes. Using the B-Mode ultrasound, an abnormal hilum was seen in 75%. The accuracy of color Doppler US reached 82.7%. CONCLUSIONS: Sonoelastography may be superior to other US modalities in elucidating different cervical lymph node biopsy helping to distinguish benign from malignant lesions. This may replace the lymph node biopsies in the future. Moreover, its use in the follow-up of patients with cervical malignancies may reduce the number of future biopsies. Further studies with more patients may be needed for a better assessment of results.

Improvement of rat liver graft quality by pifithrin-alpha-mediated inhibition of hepatocyte necrapoptosis.

Early graft dysfunction due to ischemia reperfusion injury remains a major clinical challenge in liver transplantation. Because apoptosis may contribute to graft dysfunction, we studied whether transient inhibition of p53 is capable of improving graft quality by reducing apoptotic cell death. Rat livers were harvested and stored for 24 hours or 48 hours in a 4 degrees C solution containing either pifithrin-alpha (PFT-alpha), a specific p53-inhibitor, or the vehicle dimethyl-sulfoxide. Storage was followed by 2-hour reperfusion with 37 degrees C Krebs-Henseleit buffer in an isolated liver perfusion system. Besides caspase-3 activation, apoptosis was quantified using fluorescence microscopy and hematoxylin-eosin histology. Trypan blue allowed for assessment of cell membrane damage, indicating both secondary apoptosis and primary necrosis. Bile flow, oxygen consumption, K(+)-excretion and enzyme release served as indicators of overall graft quality. Upon 2-hour reperfusion, livers developed procaspase activation as well as a mixture of apoptotic and necrotic cell death, representing necrapoptosis. In livers that had been stored for 48 hours, necrapoptotic injury was more pronounced compared with that after 24-hour storage. PFT-alpha effectively attenuated caspase activation as well as hepatocellular apoptosis and necrosis. Attenuation of both modes of cell death by PFT-alpha was associated with improved liver function, metabolism, and integrity. Experiments with the caspase inhibitor z-VAD-fmk confirmed that apoptosis is one mode of cell death in cold ischemia reperfusion. In conclusion, inhibition of p53-dependent apoptosis by PFT-alpha reduces hepatic preservation-reperfusion injury and improves primary organ function and metabolism. Fortification of the preservation solution with PFT-alpha may represent a promising and easily applicable approach to mitigate reperfusion injury in liver transplants.

Technetium-99m labeled 1-(4-fluorobenzyl)-4-(2-mercapto-2-methyl-4-azapentyl)-4-(2-mercapto-2-methylpropylamino)-piperidine and iodine-123 metaiodobenzylguanidine for studying cardiac adrenergic function: a comparison of the uptake characteristics in vascular smooth muscle cells and neonatal cardiac myocytes, and an investigation in rats.

In developing technetium-99m-based radioligands for in vivo studies of cardiac adrenergic neurons, we compared the uptake characteristics of the (99m)Tc-labeled 1-(4-fluorobenzyl)-4-(2-mercapto-2-methyl-4-azapentyl)-4-(2-mercapto-2-methylpropylamino)-piperidine ((99m)Tc-FBPBAT) with those of the clinically established meta-[(123)I]iodobenzylguanidine ((123)I-MIBG) in rat vascular smooth muscle cells and neonatal cardiac myocytes. Furthermore, the cardiac and extracardiac uptake of both radiopharmaceuticals was assessed in intact rats and in rats pretreated with various alpha- and beta-adrenoceptor drugs, and adrenergic reuptake blocking agents. The uptake of (99m)Tc-FBPBAT and (123)I-MIBG into vascular smooth muscle cells and neonatal cardiac myocytes was rapid; more than 85% of the radioactivity accumulation into the cells occurring within the first 3 minutes. Radioactivity uptake after a 60-minute incubation at 37 degrees C (pH 7.4) varied from 15% to 65% of the total loaded activity per million cells. In all cases, (99m)Tc-FBPBAT showed the higher uptake, relative to (123)I-MIBG, at any given cell concentration. The cellular uptake of (99m)Tc-FBPBAT was lower at 4 degrees C and 20 degrees C than at 37 degrees C. In contrast, the (123)I-MIBG uptake was only slightly temperature dependent. Inhibition experiments confirmed that the cellular uptake of (123)I-MIBG is mediated by the uptake-I carrier, whereas alpha(1)- and beta(1)-adrenoceptors were predominantly involved in the uptake of (99m)Tc-FBPBAT into the cardiovascular tissues. Biodistribution studies in rats showed that (99m)Tc-FBPBAT accumulated in myocardium after intravenous injection. Radioactivity in rat heart amounted to 2.32% and 1.91% of the injected dose per gram at 15 and 60 minutes postinjection, compared with 3.10% and 2.21% injected dose per gram of tissue (%ID/g) in the experiment with (123)I-MIBG, respectively. Prazosin, urapidil, and metoprolol were as effective as treatment with other adrenergic drugs in lowering cardiac uptake of (99m)Tc-FBPBAT. Uptake reduction was more pronounced in myocardium than in other adrenergic-rich organs, including the lung, spleen, kidney, and adrenals, suggesting that the (99m)Tc-FBPBAT uptake in myocardium specifically reflects a high degree of alpha(1)/beta(1)-receptor binding to cardiac adrenergic neurons. In comparison, reduction of cardiac and pulmonary uptake of (123)I-MIBG was effective after pretreatment of rats with desipramine and reserpine, confirming distinct neuronal binding sites for (99m)Tc-FBPBAT and (123)I-MIBG. (99m)Tc-FBPBAT was excreted via urine and to a lower degree via feces. Urine analysis 6 hours p.i. revealed that more than 40% of the total excreted radioactivity was unmetabolized (99m)Tc-FBPBAT. In conclusion, the uptake of (99m)Tc-FBPBAT in rat myocardium specifically reflects binding to cardiac adrenergic neurons. The (99m)Tc-FBPBAT uptake appears to be predominantly mediated via the alpha(1)/beta(1)-adrenoceptor pathway. These data indicate that (99m)Tc-FBPBAT, like (123)I-MIBG, may be suitable for mapping cardiac adrenergic innervation by SPET, especially for alpha(1)/beta(1)-adrenoceptors as target in numerous heart diseases.