Male kidney-specific BMAL1 knockout mice are protected from K+-deficient, high-salt diet-induced blood pressure increases.

The circadian clock protein basic helix-loop-helix aryl hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) is a transcription factor that impacts kidney function, including blood pressure (BP) control. Previously, we have shown that male, but not female, kidney-specific cadherin Cre-positive BMAL1 knockout (KS-BMAL1 KO) mice exhibit lower BP compared with littermate controls. The goal of this study was to determine the BP phenotype and immune response in male KS-BMAL1 KO mice in response to a low-K+ high-salt (LKHS) diet. BP, renal inflammatory markers, and immune cells were measured in male mice following an LKHS diet. Male KS-BMAL1 KO mice had lower BP following the LKHS diet compared with control mice, yet their circadian rhythm in pressure remained unchanged. Additionally, KS-BMAL1 KO mice exhibited lower levels of renal proinflammatory cytokines and immune cells following the LKHS diet compared with control mice. KS-BMAL1 KO mice were protected from the salt-sensitive hypertension observed in control mice and displayed an attenuated immune response following the LKHS diet. These data suggest that BMAL1 plays a role in driving the BP increase and proinflammatory environment that occurs in response to an LKHS diet.NEW & NOTEWORTHY We show here, for the first time, that kidney-specific BMAL1 knockout mice are protected from blood pressure (BP) increases and immune responses to a salt-sensitive diet. Other kidney-specific BMAL1 knockout models exhibit lower BP phenotypes under basal conditions. A salt-sensitive diet exacerbates this genotype-specific BP response, leading to fewer proinflammatory cytokines and immune cells in knockout mice. These data demonstrate the importance of distal segment BMAL1 in BP and immune responses to a salt-sensitive environment.

Adrenal-Specific KO of the Circadian Clock Protein BMAL1 Alters Blood Pressure Rhythm and Timing of Eating Behavior.

Brain and muscle ARNT-like 1 (BMAL1) is a core circadian clock protein and transcription factor that regulates many physiological functions, including blood pressure (BP). Male global Bmal1 knockout (KO) mice exhibit ∼10 mmHg reduction in BP, as well as a blunting of BP rhythm. The mechanisms of how BMAL1 regulates BP remains unclear. The adrenal gland synthesizes hormones, including glucocorticoids and mineralocorticoids, that influence BP rhythm. To determine the role of adrenal BMAL1 on BP regulation, adrenal-specific Bmal1 (ASCre/+ ::Bmal1) KO mice were generated using aldosterone synthase Cre recombinase to KO Bmal1 in the adrenal gland zona glomerulosa. We confirmed the localization and efficacy of the KO of BMAL1 to the zona glomerulosa. Male ASCre/+ ::Bmal1 KO mice displayed a shortened BP and activity period/circadian cycle (typically 24 h) by ∼1 h and delayed peak of BP and activity by ∼2 and 3 h, respectively, compared with littermate Cre- control mice. This difference was only evident when KO mice were in metabolic cages, which acted as a stressor, as serum corticosterone was increased in metabolic cages compared with home cages. AS Cre/+ ::Bmal1 KO mice also displayed altered diurnal variation in serum corticosterone. Furthermore, these mice have altered eating behaviors where they have a blunted night/day ratio of food intake, but no change in overall food consumed compared with controls. Overall, these data suggest that adrenal BMAL1 has a role in the regulation of BP rhythm and eating behaviors.

Alteraciones cardiacas y desaturación en pacientes con ventilación mecánica invasiva con sedación intravenosa continua vs interrupción diaria de sedación / Cardiac events and desaturation in patients under invasive mechanical ventilation with continuous intravenous sedation vs daily interruption of sedation / Desordens cardíacas e dessaturação em pacientes com ventilação mecânica invasiva com sedação intravenosa contínua vs interrupção diária da sedação

Resumen: Introducción: la sedación en pacientes críticos que requieren ventilación mecánica es un punto importante para brindarles seguridad y comodidad. En la actualidad el tratamiento del paciente crítico basado en la escala ABCDEF (A [assess]: valorar, prevenir y manejar el dolor. B [both]: protocolos de interrupción diaria de sedación y protocolo de respiración espontánea. C [choice]: elección de analgesia y sedación. D [delirium]: valorar, prevenir y manejar el delirio. E [early]: ejercicio y movilidad temprana. F [family]: inclusión y habilitación familiar) recomienda la interrupción diaria de la sedación y un protocolo diario de respiración espontánea, el cual ha demostrado mejoría en los resultados clínicos (días en ventilación mecánica, delirio). Éste contrasta con el manejo frecuente de sedación intravenosa continua, por lo que en este estudio se comparó la seguridad de estas dos formas de sedación (interrupción diaria versus intravenosa continua). Objetivo: comparar la incidencia de eventos cardiovasculares y desaturación entre un protocolo de interrupción diaria de sedación en pacientes con ventilación mecánica invasiva (VMI) contra sedación intravenosa continua en pacientes con ventilación mecánica invasiva. Material y métodos: tipo de estudio descriptivo comparativo, retrospectivo. Resultados: no se demostró una diferencia estadísticamente significativa en incidencia de eventos cardiacos y desaturación entre pacientes con sedación intravenosa continua y protocolo de interrupción diaria de sedación. Conclusión: la sedación intravenosa continua y el protocolo de interrupción diaria de sedación son igual de seguras en pacientes bajo VMI.

Abstract: Introduction: sedation in the critically patient requiring mechanical ventilation is an important intervention used to provide safety and comfort to the patient. Currently, the management of critically ill patients is based on the ABCDEF bundle (A [assess]: prevent and manage pain. B [both]: protocols for daily interruption of sedation and spontaneous breathing protocol. C [choice]: of analgesia and sedation. D [delirium]: assess, prevent and manage delirium. E [early]: exercise and early mobility. F [family]: inclusion and empowerment) which recommends daily interruption of sedation and a daily spontaneous breathing protocol, it has shown improvement in clinical outcomes (days on mechanical ventilation, delirium). This contrasts with the frequent management of continuous intravenous sedation. Therefore, in this study the safety of these two forms of sedation (daily interruption vs continuous intravenous) will be compared. Objective: to compare the incidence of cardiovascular events and desaturation between a protocol of daily interruption of sedation in patients with invasive mechanical ventilation versus continuous intravenous sedation in patients with invasive mechanical ventilation. Material and methods: retrospective comparative descriptive study. Results: there was no statistically significant difference in the incidence of cardiac events and desaturation between patients with continuous intravenous sedation and daily sedation interruption protocol. Conclusion: continuous intravenous sedation and daily interruption of sedation protocol are equally safe in critically ill patients.

Resumo: Introdução: a sedação em pacientes críticos que necessitam de ventilação mecânica é um ponto importante para proporcionar segurança e conforto ao paciente. Atualmente, o tratamento de pacientes críticos é baseado na escala ABCDEF (A [assess]: avaliar, prevenir e controlar a dor. B [both]: protocolos de interrupção diária da sedação e protocolo de respiração espontânea. C [choice]: escolha da analgesia e sedação. D [delirium]: avaliar, prevenir e controlar delirium. E [early]: exercício e mobilidade precoce. F [family]: inclusão e qualificação da família) recomenda interrupção diária da sedação e protocolo diário de respiração espontânea, que tem mostrado melhora nos desfechos clínicos (dias em ventilação mecânica, delirium). Isso contrasta com o manejo frequente da sedação intravenosa contínua. Portanto, neste estudo foi comparada a segurança dessas duas formas de sedação (interrupção diária vs intravenosa contínua). Objetivo: comparar a incidência de eventos cardiovasculares e dessaturação entre um protocolo diário de interrupção da sedação em pacientes com ventilação mecânica invasiva versus sedação intravenosa contínua em pacientes com ventilação mecânica invasiva. Material e métodos: tipo de estudo comparativo descritivo, retrospectivo. Resultados: não houve diferença estatisticamente significativa na incidência de eventos cardíacos e dessaturação entre pacientes com sedação intravenosa contínua e protocolo de interrupção diária da sedação. Conclusão: a sedação intravenosa contínua e o protocolo diário de interrupção da sedação são igualmente seguros em pacientes submetidos à ventilação mecânica invasiva.

Pituitary Infiltration by Lymphoma.

Lymphoma infiltration to the pituitary is rare. It represents less than 0.5% of all reported pituitary metastases (PMs). Here we present a case series of 3 patients with PMs from a systemic lymphoma. Also, we performed a literature review of the cases reported. We identified additional 31 cases in which non-Hodgkin lymphoma (NHL) was the most common (n = 28, 90%), with large B-cell NHL the most frequent histological subtype (n = 14, 45%). Central hypothyroidism (n = 21, 67%) was the most frequent pituitary deficiency followed by adrenal insufficiency (n = 19, 61%) and diabetes insipidus (DI; n = 18, 58%). Full endocrine recovery was found in only 12% (n = 4) of patients after treatment, and magnetic resonance imaging showed tumor regression in 22% of them. In our series, 2 patients were diagnosed with diffuse large B-cell lymphoma, and 1 had mixed cellularity of classic Hodgkin lymphoma. The mean age was 54 ± 6.92 years. Hypopituitarism and DI were present in all of them, with 100% of mortality because of advanced systemic disease.

Correction: In-hospital mortality from severe COVID-19 in a tertiary care center in Mexico City; causes of death, risk factors and the impact of hospital saturation.

[This corrects the article DOI: 10.1371/journal.pone.0245772.].

Intoxicación por rodenticida anticoagulante de acción prolongada ¿Publicación duplicada? (1)

Tocante al artículo "Intoxicación humana intencional por rodenticida anticoagulante de acción prolongada", enviado a la Revista de la SPMI (febrero de 2021)1, manifiesto, que:

Heterogeneity of Genetic Admixture Determines SLE Susceptibility in Mexican.

Systemic Lupus Erythematosus (SLE) is an autoimmune inflammatory disorder for which Major Histocompatibility Complex (MHC) genes are well identified as risk factors. SLE patients present different clinical phenotypes, which are partly explained by admixture patterns variation among Mexicans. Population genetic has insight into the high genetic variability of Mexicans, mainly described through HLA gene studies with anthropological and biomedical importance. A prospective, case-control study was performed. In this study, we recruited 146 SLE patients, and 234 healthy individuals were included as a control group; both groups were admixed Mexicans from Mexico City. The HLA typing methods were based on Next Generation Sequencing and Sequence-Based Typing (SBT). The data analysis was performed with population genetic programs and statistical packages. The admixture estimations based on HLA-B and -DRB1 revealed that SLE patients have a higher Southwestern European ancestry proportion (48 ± 8%) than healthy individuals (30 ± 7%). In contrast, Mexican Native American components are diminished in SLE patients (44 ± 1%) and augmented in Healthy individuals (63 ± 4%). HLA alleles and haplotypes' frequency analysis found variants previously described in SLE patients from Mexico City. Moreover, a conserved extended haplotype that confers risk to develop SLE was found, the HLA-A∗29:02∼C∗16:01∼B∗44:03∼DRB1∗07:01∼DQB1∗02:02, pC = 0.02, OR = 1.41. Consistent with the admixture estimations, the origin of all risk alleles and haplotypes found in this study are European, while the protection alleles are Mexican Native American. The analysis of genetic distances supported that the SLE patient group is closer to the Southwestern European parental populace and farthest from Mexican Native Americans than healthy individuals. Heterogeneity of genetic admixture determines SLE susceptibility and protection in Mexicans. HLA sequencing is helpful to determine susceptibility alleles and haplotypes restricted to some populations.

In-hospital mortality from severe COVID-19 in a tertiary care center in Mexico City; causes of death, risk factors and the impact of hospital saturation.

BACKGROUND: As the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has remained in Latin America, Mexico has become the third country with the highest death rate worldwide. Data regarding in-hospital mortality and its risk factors, as well as the impact of hospital overcrowding in Latin America has not been thoroughly explored. METHODS AND FINDINGS: In this prospective cohort study, we enrolled consecutive adult patients hospitalized with severe confirmed COVID-19 pneumonia at a SARS-CoV-2 referral center in Mexico City from February 26th, 2020, to June 5th, 2020. A total of 800 patients were admitted with confirmed diagnosis, mean age was 51.9 ± 13.9 years, 61% were males, 85% were either obese or overweight, 30% had hypertension and 26% type 2 diabetes. From those 800, 559 recovered (69.9%) and 241 died (30.1%). Among survivors, 101 (18%) received invasive mechanical ventilation (IMV) and 458 (82%) were managed outside the intensive care unit (ICU); mortality in the ICU was 49%. From the non-survivors, 45.6% (n = 110) did not receive full support due to lack of ICU bed availability. Within this subgroup the main cause of death was acute respiratory distress syndrome (ARDS) in 95% of the cases, whereas among the non-survivors who received full (n = 105) support the main cause of death was septic shock (45%) followed by ARDS (29%). The main risk factors associated with in-hospital death were male sex (RR 2.05, 95% CI 1.34-3.12), obesity (RR 1.62, 95% CI 1.14-2.32)-in particular morbid obesity (RR 3.38, 95%CI 1.63-7.00)-and oxygen saturation < 80% on admission (RR 4.8, 95%CI 3.26-7.31). CONCLUSIONS: In this study we found similar in-hospital and ICU mortality, as well as risk factors for mortality, compared to previous reports. However, 45% of the patients who did not survive justified admission to ICU but did not receive IMV / ICU care due to the unavailability of ICU beds. Furthermore, mortality rate over time was mainly due to the availability of ICU beds, indirectly suggesting that overcrowding was one of the main factors that contributed to hospital mortality.

Low Thoracic Skeletal Muscle Area Is Not Associated With Negative Outcomes in Patients With COVID-19.

OBJECTIVE: Sarcopenia has been related to negative outcomes in different clinical scenarios from critical illness to chronic conditions. The aim of this study was to verify whether there was an association between low skeletal muscle index and in-hospital mortality, intensive care unit admission, and invasive mechanical ventilation need in hospitalized patients with COVID-19. DESIGN: This was a retrospective cohort study of a referral center for COVID-19. We included all consecutive patients admitted to the hospital between February 26 and May 15, 2020, with a confirmed diagnosis of COVID-19. Skeletal muscle index was assessed from a transverse computed tomography image at the level of twelfth thoracic vertebra with National Institutes of Health ImageJ software, and statistical analysis was performed to find an association between skeletal muscle index and in-hospital mortality, need of invasive mechanical ventilation, and intensive care unit admission. RESULTS: We included 519 patients, the median age was 51 (42-61) yrs, and 115 patients (22%) had low skeletal muscle index. On multivariable analysis, skeletal muscle index was not associated with mortality, intensive care unit admission, or invasive mechanical ventilation need nor in a subanalysis of patients 65 yrs or older. CONCLUSIONS: Skeletal muscle index determined by computed tomography at the level of twelfth thoracic vertebra was not associated with negative outcomes in hospitalized patients with COVID-19.

Combined Endoscopic-Robotic Resection of a Giant Polyp to Avoid Colorectal Resection.

Colorectal cancer prevention relies on effective screening through colonoscopy and polypectomy. Several techniques and methods have been described to manage complex colonic polyps such as the ones that are endoscopically unresectable. Across time, we have been able to perform less invasive techniques that include different types of colonic resections, ranging from partial thickness, full-thickness and, segmental colectomies, however, none has proven to be the treatment of choice for these lesions. The technique presented here is an attractive alternative to segmental colectomy using a robotic platform to perform a full-thickness resection.

Native American ancestry significantly contributes to neuromyelitis optica susceptibility in the admixed Mexican population.

Neuromyelitis Optica (NMO) is an autoimmune disease with a higher prevalence in non-European populations. Because the Mexican population resulted from the admixture between mainly Native American and European populations, we used genome-wide microarray, HLA high-resolution typing and AQP4 gene sequencing data to analyze genetic ancestry and to seek genetic variants conferring NMO susceptibility in admixed Mexican patients. A total of 164 Mexican NMO patients and 1,208 controls were included. On average, NMO patients had a higher proportion of Native American ancestry than controls (68.1% vs 58.6%; p = 5 × 10-6). GWAS identified a HLA region associated with NMO, led by rs9272219 (OR = 2.48, P = 8 × 10-10). Class II HLA alleles HLA-DQB1*03:01, -DRB1*08:02, -DRB1*16:02, -DRB1*14:06 and -DQB1*04:02 showed the most significant associations with NMO risk. Local ancestry estimates suggest that all the NMO-associated alleles within the HLA region are of Native American origin. No novel or missense variants in the AQP4 gene were found in Mexican patients with NMO or multiple sclerosis. To our knowledge, this is the first study supporting the notion that Native American ancestry significantly contributes to NMO susceptibility in an admixed population, and is consistent with differences in NMO epidemiology in Mexico and Latin America.

Diversity of HLA Class I and Class II blocks and conserved extended haplotypes in Lacandon Mayans.

Here we studied HLA blocks and haplotypes in a group of 218 Lacandon Maya Native American using a high-resolution next generation sequencing (NGS) method. We assessed the genetic diversity of HLA class I and class II in this population, and determined the most probable ancestry of Lacandon Maya HLA class I and class II haplotypes. Importantly, this Native American group showed a high degree of both HLA homozygosity and linkage disequilibrium across the HLA region and also lower class II HLA allelic diversity than most previously reported populations (including other Native American groups). Distinctive alleles present in the Lacandon population include HLA-A*24:14 and HLA-B*40:08. Furthermore, in Lacandons we observed a high frequency of haplotypes containing the allele HLA-DRB1*04:11, a relatively frequent allele in comparison with other neighboring indigenous groups. The specific demographic history of the Lacandon population including inbreeding, as well as pathogen selection, may have elevated the frequencies of a small number of HLA class II alleles and DNA blocks. To assess the possible role of different selective pressures in determining Native American HLA diversity, we evaluated the relationship between genetic diversity at HLA-A, HLA-B and HLA-DRB1 and pathogen richness for a global dataset and for Native American populations alone. In keeping with previous studies of such relationships we included distance from Africa as a covariate. After correction for multiple comparisons we did not find any significant relationship between pathogen diversity and HLA genetic diversity (as measured by polymorphism information content) in either our global dataset or the Native American subset of the dataset. We found the expected negative relationship between genetic diversity and distance from Africa in the global dataset, but no relationship between HLA genetic diversity and distance from Africa when Native American populations were considered alone.

Applications of stem cells and bioprinting for potential treatment of diabetes.

Currently, there does not exist a strategy that can reduce diabetes and scientists are working towards a cure and innovative approaches by employing stem cell-based therapies. On the other hand, bioprinting technology is a novel therapeutic approach that aims to replace the diseased or lost ß-cells, insulin-secreting cells in the pancreas, which can potentially regenerate damaged organs such as the pancreas. Stem cells have the ability to differentiate into various cell lines including insulin-producing cells. However, there are still barriers that hamper the successful differentiation of stem cells into ß-cells. In this review, we focus on the potential applications of stem cell research and bioprinting that may be targeted towards replacing the ß-cells in the pancreas and may offer approaches towards treatment of diabetes. This review emphasizes on the applicability of employing both stem cells and other cells in 3D bioprinting to generate substitutes for diseased ß-cells and recover lost pancreatic functions. The article then proceeds to discuss the overall research done in the field of stem cell-based bioprinting and provides future directions for improving the same for potential applications in diabetic research.

Late Pleistocene to early Holocene high-quality quartz crystal procurement from the Valiente quarry workshop site (32°S, Chile, South America).

The procurement of high-quality lithic resources is amongst the most indicative processes of decision-making in the archaeology of early human groups peopling the Americas. Directly dated deposits from quarry workshops have been absent of the late Pleistocene record of South America. We present the results of the excavations of a high-quality translucent quartz crystal workshop that yielded radiocarbon-dated coherently layered stratigraphic deposits that shed light into the behavior of the initial stages of lithic procurement. Based on a detailed analysis of the context of the Valiente site (32° S, Chile, South America), we discuss the stages of bifacial production of point technology. The deposit produced evidence of cumulative occupations over the period between 12,630 and 11,320 calibrated years before present. This ~1,300-year span is coincidental with a major environmental step-wise drying trend as indicated by the local and regional pollen records. Furthermore, it is synchronous to the process in which natural landscapes became the earliest taskscapes in the region, thereby encompassing major cultural changes related to the organization of the land use. These results are discussed in the frame of contemporaneous archaeological data to discuss specific aspects of technology and decision-making of the earliest settlers of South America.

Clustering coefficient and periodic orbits in flow networks.

We show that the clustering coefficient, a standard measure in network theory, when applied to flow networks, i.e., graph representations of fluid flows in which links between nodes represent fluid transport between spatial regions, identifies approximate locations of periodic trajectories in the flow system. This is true for steady flows and for periodic ones in which the time interval τ used to construct the network is the period of the flow or a multiple of it. In other situations, the clustering coefficient still identifies cyclic motion between regions of the fluid. Besides the fluid context, these ideas apply equally well to general dynamical systems. By varying the value of τ used to construct the network, a kind of spectroscopy can be performed so that the observation of high values of mean clustering at a value of τ reveals the presence of periodic orbits of period 3τ, which impact phase space significantly. These results are illustrated with examples of increasing complexity, namely, a steady and a periodically perturbed model two-dimensional fluid flow, the three-dimensional Lorenz system, and the turbulent surface flow obtained from a numerical model of circulation in the Mediterranean sea.

Percolation-based precursors of transitions in extended systems.

Abrupt transitions are ubiquitous in the dynamics of complex systems. Finding precursors, i.e. early indicators of their arrival, is fundamental in many areas of science ranging from electrical engineering to climate. However, obtaining warnings of an approaching transition well in advance remains an elusive task. Here we show that a functional network, constructed from spatial correlations of the system's time series, experiences a percolation transition way before the actual system reaches a bifurcation point due to the collective phenomena leading to the global change. Concepts from percolation theory are then used to introduce early warning precursors that anticipate the system's tipping point. We illustrate the generality and versatility of our percolation-based framework with model systems experiencing different types of bifurcations and with Sea Surface Temperature time series associated to El Niño phenomenon.

Anatomical study of the pterygomaxillary area for implant placement: cone beam computed tomographic scanning in 100 patients.

PURPOSE: The aim of this study was to describe the average angulation and dimensions of the pterygomaxillary area in the atrophic maxilla to facilitate the orientation of pterygoid implants during their placement. MATERIALS AND METHODS: A retrospective radiologic study was made. A virtual pterygoid implant, 13, 15, or 18 mm long, was placed in the pterygomaxillary area following the axis of the bone, with a distance of at least 2 mm maintained between the artery and palatine nerve and the implant. The long axis of the implant was inclined slightly toward the palatal to follow the cortical palatal bone. The angles between the long axis of the virtual implant and Frankfort horizontal were measured in both sagittal and frontal views. To calculate the average length of the pterygomaxillary area, the virtual long axis of the implant was measured from the alveolar crest to the pterygomaxillary suture. RESULTS: The average anteroposterior axis inclination of the pterygomaxillary area was 72.5 ± 4.9 degrees relative to Frankfort horizontal. The average angulation of the palatal vestibule was 81.3 ± 42.8 degrees relative to Frankfort horizontal. The average length of the pterygomaxillary area was 22.5 ± 4.8 mm. CONCLUSION: Pterygoid implant placement requires thorough knowledge of each patient's anatomy and individual needs. The mean position of the pterygomaxillary buttress axis was 72.5 ± 4.9 degrees to the distal and 81.3 ± 2.8 degrees to the palatal relative to Frankfort horizontal. Placement of pterygoid implants in this inclination may increase accuracy of implant placement. The average length from the tuberosity to the most apical point of the pterygoid apophysis was 22.5 ± 4.8 mm. These results suggest that an implant 15 to 18 mm in length would fit in the pterygomaxillary area to reach the cortical bone.

The effect of abutment dis/reconnections on peri-implant bone resorption: a radiologic study of platform-switched and non-platform-switched implants placed in animals.

OBJECTIVES: The purpose of this animal study was to radiologically measure the influence of abutment disconnection on bone resorption and to compare this influence on platform-switched vs. non-platform-switched implants. METHODS: The study design included extraction of all mandibular premolars in five canines . After 2 months, six implants were placed in each dog. Four of them were platform-switched (PS) implants and two were non-platform-switched (NPS) implants. Some or all of the abutments connected to the implants were disconnected at pre-ordained post-surgical intervals. Radiographs were taken at the time of implant placement and at every handling. The values for mesial (horizontal and vertical) and distal (horizontal and vertical) bone resorption were taken and compared for each implant at every abutment dis/reconnection. RESULTS: The average vertical bone resorption around NPS implants after four dis/reconnections was 1.09 mm (SD 0.25 mm), and the average horizontal bone resorption was 0.98 mm (SD 0.27 mm). The average vertical bone resorption around PS implants after four dis/reconnections was 0.24 mm, (SD 0.08 mm) and the average horizontal bone resorption was 0.24 mm (SD 0.13 mm). The difference of the average horizontal and vertical bone resorption around NPS (site D) and PS (site A) implants was statically significant (P < 0.05). The average mesial and distal bone resorption values around PS (site A) implant adjacent to a tooth were compared, and statically significant differences were found (P < 0.05). CONCLUSIONS: Implants with a PS design show less peri-implant bone resorption during the healing process and as their abutments are disconnected, than do comparably dis/reconnected NPS implants. The location of the PS implant next to a tooth may decrease radiographically visible peri-implant bone resorption significantly.

Modified surgical protocol for placing implants in the pterygomaxillary region: clinical and radiologic study of 454 implants.

PURPOSE: To review a series of 454 pterygoid implants placed more vertically than the previous standard angle (45 degrees) over a functional loading period ranging from 2 months to 14 years with a mean follow-up period of 6 years. MATERIALS AND METHODS: A retrospective study was made. The sample was composed of patients rehabilitated with pterygoid implants between January 1997 and December 2010. Patient selection criteria included: edentulism on the posterior area of an atrophic maxilla, with less than 8 mm remaining from the sinus floor to the alveolar crest, and the presence of an anterior implant or tooth to ensure mesial support for a partial denture. After a healing period between 2 and 7 months, panoramic x-rays were taken at the time of loading. The implant length, implant diameter, implant success, and the angulation of the pterygoid implants were measured. RESULTS: Three hundred ninety-two patients (206 women and 186 men) ranging in age from 34 to 75 years were fitted with 454 pterygoid implants and followed up. The 18-mm implant length was the most favored implant to fit in the pterygoid area. Implant diameter was 3.75 mm in 448 cases (98.6%). The mean mesiodistal angulation of the pterygoid implants was 70.4 degrees±7.2. After a mean follow-up period of 6 years, 96.5% of the implants placed were successfully osseointegrated. CONCLUSIONS: The findings indicate that a mesiodistal inclination of the pterygoid implant at 70 degrees relative to the Frankfort plane following the bony column of the pterygoid region decreases the non-axial loads of the rehabilitations and exhibits good long-term survival; however, further studies are needed to assess the long-term survival of implants in the pterygomaxillary region.