Loss Of Wall Research Articles

Sodium nitroprusside applications modulate cell wall degrading enzymes and preserves the postharvest quality of cold-stored mangoes

ABSTRACT Mango fruit undergoes various physiochemical changes after its harvest that affect consumer acceptability. The present research work was carried out to evaluate the preservation effect of sodium nitroprusside (SNP) treatments on the postharvest quality of mango cv. Langra fruits at 12 ± 1°C for 35 days. The results revealed that SNP 1.0 mM treated fruits exhibited reduced weight loss (6.94%), decay incidence (8.05%), and activities of cell wall degrading enzymes like polygalacturonase and pectin methyl esterase in comparison to uncoated fruits on the last day of storage. Furthermore, the treatment maintained higher fruit firmness (56.77 N) along with fruit quality parameters like soluble solid content (16.24%), titratable acidity (0.20%), starch (4.99%), and, total flavonoid content (12.92 mg/100 g). Overall, SNP 1.0 mM combined with low-temperature storage was proved to be the most effective in extending the shelf life and preserving the quality characteristics of mango fruits.

Feasibility of Immediate, Early and Delayed Implant Placement for Single Tooth Replacement in the Premaxilla: A Retrospective Cone-Beam Computed Tomography Study of 100 Cases.

To assess the feasibility of immediate (IIP), early (EIP) and delayed implant placement (DIP) for single tooth replacement in the premaxilla on the basis of the complete indication area of each approach in routine practice. Data from 100 patients (59 women, 41 men, all Caucasians) aged between 19 and 81 years old (mean age 51.71) who had been consecutively treated with a single implant in the premaxilla (13-23) in one private periodontal practice were retrospectively collected. Demographic data, diagnostic information and linear measurements were extracted from patient files and CBCTs. The feasibility of IIP, EIP and DIP was assessed for all cases by both authors, based on the following criteria: availability of apical bone, position of the tooth in relation to the morphology of the alveolar process, buccal bone morphology and presence of midfacial recession. The reasons for not being able to perform an approach, and the viable alternatives for each approach were secondary outcomes. DIP was considered to have been preceded by alveolar ridge preservation (ARP). Ninety-two patients could be treated by means of IIP, EIP or DIP. In eight patients none of these approaches were possible as they required bone augmentation prior to implant placement. Fifty-two patients (95% CI: 42%-62%) could by treated with IIP, 58 (95% CI: 48%-67%) with EIP and 88 (95% CI: 80%-93%) with DIP. The feasibility proportions of IIP and EIP were significantly lower than the one of DIP (p < 0.001). All patients who could be treated with IIP could also be treated with EIP or DIP. Lack of apical bone for implant anchorage was the main reason for not being able to perform IIP and EIP. Complete loss of the buccal bone wall and the need for bone augmentation prior to implant placement were the reasons for not being able to perform DIP. From the results of this retrospective CBCT analysis, DIP is nearly always possible in contrast to IIP and EIP. Therefore, and since it is much easier than IIP and EIP, inexperienced clinicians should mainly focus on ARP and DIP in clinical practice deferring IIP and EIP until more surgical skills have been acquired.

Combined application of hot water and hexanal-based formulations preserves the postharvest quality of mango fruits.

Mango fruits undergo numerous postharvest quality losses during storage. Hence, the present study aimed to increase the shelf life of mango fruits by applying hexanal-based enhanced freshness formulations (EFF) in combination with hot water treatment (HWT). The findings revealed that, among all the tested applications, the combination of EFF 1.0% + HWT reduced the weight loss, decay incidence, and activity of cell wall degrading enzymes of mango fruits. Also, the combined treatment was effective in maintaining the fruit quality parameters such as soluble solid contents, titratable acidity, ascorbic acid and activity of antioxidant compounds. The present study concludes that the postharvest application of EEF 1.0% in combination with HWT can be used in extending the shelf life of mango cv. 'Langra,' fruits stored at 12° C and 85-90% relative humidity for 35 days. © 2024 Society of Chemical Industry.

Seismic responses and loss evaluation of RC frame with slotted infill walls

Infill walls are a primary source of structural loss under service level and design basis earthquakes, so developing high-performance infill wall is an effective strategy to reduce seismic loss. While several high-performance infill walls have been proposed, most studies only reveal the damage characteristics of infill walls at the component level. However, the interaction between infill walls and structures can alter the seismic response of structures and consequently affect the loss of infill walls under earthquakes. Therefore, it is necessary to investigate the seismic responses and loss of high-performance infill wall at the structural level. In this paper, the working mechanism and damage characteristics of the slotted infill wall (SIW) are firstly introduced and verified through cyclic loading test. Then, an in-plane hysteresis model of SIW is developed, and the calculation method of key parameters is proposed. Finally, a numerical analysis model of a 10-story frame with slotted infill wall (SIW-F) is developed to study the seismic response and seismic losses. The results indicate that SIW-F’s displacement response is larger than that of the frame with ordinary infill wall (OIW-F) on most floors. However, the floor acceleration response is less. The seismic loss of SIW-F is less than that of OIW-F, particularly under design basis earthquakes. The repair cost ratio of infill wall decreases from 19% to 8%, the total repair cost of the SIW-F decreases by 41%, and the total repair time also reduces by 25%.

The influence of connective tissue grafting on the reconstruction of a missing facial bone wall using immediate implant placement and simultaneous bone reconstruction: a retrospective long-term cohort study

PurposeThis retrospective cohort study evaluates the influence of connective tissue grafts (CTG) on bone regeneration at implant sites with total loss of the buccal bone wall treated with flapless immediate implant placement (IIP) and reconstruction with autogenous bone chips (AB) within a follow-up of up to 13 years.MethodsSixty implants were inserted in 55 patients in sites with total loss of the buccal bone wall between 2008 and 2021. The implants were inserted and the buccal gaps were grafted by AB. A subgroup of 34 sites was grafted additionally with CTG using tunnel technique. Primary outcome was the vertical bone regeneration in height and thickness. Secondary outcome parameters were interproximal marginal bone level, recession, soft tissue esthetics (PES), width of keratinized mucosa (KMW) and probing depths (PPD).ResultsMean follow-up period was 60.8 months. In 55 sites a complete vertical bone regeneration was documented. The mean buccal bone level increased by 10.6 mm significantly. The thickness of the buccal bone wall ranged between 1.7 and 1.9 mm, and was significantly thicker in sites without CTG. Interproximal marginal bone level was at implant shoulder level. The mean recession improved significantly by 1.2 mm. In sites with CTG, recessions and PES improved significantly more.ConclusionsAdditional CTG in extraction sites with total buccal bone loss followed by IIP with simultaneous AB grafting led to improved PES and recession, but also to a thinner buccal bone wall compared to sites grafted just with AB.Graphical

Analyzing the combustion characteristics of premixed methane-oxygen with different hydrogen addition ratios in a catalytic micro-combustor

Experimental and numerical study of premixed methane-oxygen combustion characteristics in a catalytic micro-combustor with different hydrogen addition ratios has been presented in this paper. The objective is to examine the effects of platinum catalysts and hydrogen additions on methane and oxygen combustion. The simulation of a three-dimensional micro rectangular model was carried out with a gas phase reaction mechanism combined with a surface reaction mechanism, and the model was validated with experimental results with a maximum deviation of just 1.56 percent. In the experimental phase, the effects of flammability limit, equivalence ratio, and inlet velocity were studied, while in the numerical phase, the effect of hydrogenation on combustion characteristics was investigated. Experimental results show that adding 10 % hydrogen to a premixed methane-oxygen mixture significantly increases its flammability limit. The maximum external wall temperature along the centerline was observed at an equivalent ratio of 1. Additionally, an increase in the inlet velocity leads to a corresponding increase in the external wall centerline temperature. Catalytic reaction wall temperatures show a gradual decline, with the highest temperatures located at the inlet. An observed trend revealed a decrease in the external wall centerline temperature as the hydrogen addition increased from 0 % to 40 % due to the reduced total heating value of the blended fuel. Due to its higher reactivity and ability to promote complete combustion, hydrogen also plays an important role in CH4 and O2 conversion. In addition, CO and CO2 emissions decreased with increased hydrogen percentage in fuel mixtures. Furthermore, hydrogen addition can reduce external wall heat losses as well. After adding 0–40 % hydrogen to a premixture of (CH4–O2) fuel, the total heat loss of the external wall was reduced from 19.48 W to 17.11 W.

Evaluation of biophysical alterations in the epithelial and endothelial layer of patients with Bullous Keratopathy

The cornea is a fundamental ocular tissue for the sense of sight. Thanks to it, the refraction of two-thirds of light manages to participate in the visual process and protect against mechanical damage. Because it is transparent, avascular, and innervated, the cornea comprises five main layers: Epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium. Each layer plays a key role in the functionality and maintenance of ocular tissue, providing unique ultrastructural and biomechanical properties. Bullous Keratopathy (BK) is an endothelial dysfunction that leads to corneal edema, loss of visual acuity, epithelial blisters, and severe pain, among other symptoms. The corneal layers are subject to changes in their biophysical properties promoted by Keratopathy. In this context, the Atomic Force Microscopy (AFM) technique in air was used to investigate the anterior epithelial surface and the posterior endothelial surface, healthy and with BK, using a triangular silicone tip with a nominal spring constant of 0.4 N/m. Six human corneas (n = 6) samples were used for each analyzed group. Roughness data, calculated by third-order polynomial adjustment, adhesion, and Young's modulus, were obtained to serve as a comparison and identification of morphological and biomechanical changes possibly associated with the pathology, such as craters and in the epithelial layer and exposure of a fibrotic layer due to loss of the endothelial cell wall. Endothelial cell membrane area and volume data were calculated, obtaining a relevant comparison between the control and patient. Such results may provide new data on the physical properties of the ocular tissue to understand the physiology of the cornea when it has pathology.

Bilateral rectus muscle turning-over for complicated and eventrated abdominal wall hernias: results of a novel method.

We present a technique for covering large midline loss of abdominal wall using a novel method by autologous tissues. Twenty-two patients (body mass index = 35,6 ± 6,9 kg/m2) were involved in the prospective cohort study. Acute and elective cases were included. The gap area was 450.1 ± 54 cm2. The average width of the midline gap was 16,3 ± 3,2 cm. The rectus muscles were mobilized from its posterior sheath. Both muscles were turned by180º medially, so that the complete abdominal wall gap could be covered without considerable tension. Changes in intra-abdominal pressure, quality of life and hernia recurrency were determined. There was no significant increase in the intra-abdominal pressure. Wound infection and seroma occurred in four cases. Bleeding occurred in one case. Pre- and post-operative quality of life index significantly improved (23 ± 13 vs. 47 ± 6; p = 0,0013). One recurrent hernia was registered. The procedure could be performed safely and yielded excellent results. The method was applied in acute cases. The intact anatomical structure of rectus muscles was essential. The midline reconstruction with bilateral turned-over rectus muscles provided low tension abdominal wall status, and it did not require synthetic mesh implantation.

Taphonomic significance of Aristotle's 'Wheel Paradox': an example with the cerithid gastropod Cerithium atratum (Born, 1778) from Conceição Lagoon, Santa Catarina State, Southern Brazil

In the book Mechanical Problems, attributed to Aristotle, the author relates the differential degrees of wearing and rounding of pebbles and shells moved by waves on the seashore to the variable radii and diameters of these particles. This phenomenon, which became known as Aristotle’s ‘Wheel Paradox,’ seems to explain the pattern of abrasion observed in shells of gastropods Cerithium atratum (Born) found in Conceição Lagoon, on the Island of Santa Catarina, Brazil. In situ observations show that the elongated turriform shells of C. atratum deposited at shallow (&lt; 30 cm) depths on a sandy bottom with pavements of disarticulated valves of Anomalocardia flexuosa Gmelin are subject to bidirectional wave-generated currents under fairweather conditions. The 47 specimens analyzed exhibit a pattern of abrasion characterized by the loss of the shell wall, apparently proceeding from the wider last whorl toward the narrow apex, culminating in the exposure of the columella. Experiments designed to test whether this pattern could be related to the ‘Wheel Paradox’ principle show that under bidirectional flow, the shells describe circles on the vertical plane around the longitudinal axis (rolling) and a pendulum movement (revolution) on the horizontal plane centered on the apex. The whorls located farther from the apex have larger diameters and describe broader arc segments. Thus, they have higher tangential velocities and travel longer paths, which could explain why they are abraded earlier than the narrower whorls. Recognizing similar abrasion features in fossil shells can provide information on the local paleo-currents, hydrodynamics, and relative time-averaging of death assemblages and allow distinguishing between natural or anthropogenic modification in archaeological specimens. Although the effects vary between shells with different shapes, Aristotle’s ‘Wheel Paradox’ principle explains the general abrasion pattern among gastropods under certain hydrodynamic conditions. Keywords: Actualistic Taphonomy, Aktuopaläontologie, shell abrasion, shell orientation, biostratinomy, hydrodynamics

Low frequency vibration reduction bandgap characteristics and engineering application of phononic-like crystal metaconcrete material

Metaconcrete, as a new type of composite material with vibration attenuation characteristics, is formed by replacing traditional coarse aggregates with a heavy metal core wrapped with an elastic soft coating and mixing with cement mortar. However, due to the high bandgap frequency and narrow bandgap width, it is greatly limited in the engineering application of low frequency vibration control. In order to broaden the range and number of elastic wave bandgap of metaconcrete materials and solve the problem of low frequency vibration, a novel three-component cement-based phononic-like crystal model is proposed based on local resonance theory, and phononic-like crystal metaconcrete vibration reduction material is developed accordingly. Secondly, the band structure, bandgap mechanism, and frequency response function of the phononic-like crystal metaconcrete are calculated and analyzed, and indoor tests of the phononic-like crystal metaconcrete are conducted. Finally, a phononic-like crystal metaconcrete subway track bed is prepared using the developed phononic-like crystal metaconcrete material, and applied to the practical subway engineerings to solve the low frequency vibration problem generated during subway operation. The results show that the phononic-like crystal metaconcrete opens 6 low frequency bandgaps in the frequency range of 200 Hz, and the attenuation values are mostly above 10 dB in the frequency range of the bandgap, and the attenuation effect is good. Meanwhile, the on-site monitoring results show that the phononic-like crystal metaconcrete subway track bed has good low frequency vibration reduction effect in the 200 Hz frequency range. The maximum value of the one-third octave insertion loss of the tunnel wall is 13.22 dB, the maximum vertical Z-vibration level difference of the tunnel wall is 5.052 dB, and the maximum vertical frequency division vibration level difference of the tunnel wall is 5.926 dB. The maximum value of the vertical frequency division vibration level difference in the frequency range of 4–200 Hz is 13.87 dB, and the average value is 5.74 dB. The relevant research results of this paper provide a new technical approach to solve the problem of low frequency vibration in subway engineering and other engineering construction, breaking through the traditional vibration reduction control technology of civil engineering structures, and providing new idea and method for long-term vibration reduction and application of engineering structures.

Characteristics of Vibrio cholerae isolates obtained from shrimp supply chains and inhibitory activities of rambutan (Nephelium lappaceum L. cv. Rong Rian) peel aqueous extract

Vibrio cholerae is a significant seafood-borne pathogen that carries multiple virulence genes. Its ability to form biofilm on surfaces enables this pathogen to persist in the environments and resistant to chemicals and antibiotics. This study investigated the virulence properties of V. cholerae isolates obtained from shrimp supply chains and evaluated the inhibitory activities of rambutan (Nephelium lappaceum L. cv. Rong Rian) peel extract (RPE) against V. cholerae and its biofilm. A total of 46 V. cholerae were isolated and most isolates harbored vasH (T6SS) (96%) and hlyA El Tor (91%) genes. Other virulence genes including stn/sto, vcsV2 (T3SS), and tcp classical genes were detected in 9, 9, and 4% of the isolates, respectively. More than 50% of the isolates produced strong biofilms and exhibited resistant against 2 or more antibiotics. RPE exhibited good activity against all isolates with the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranging between 2048 and 4096 and 4096 to 8192 μg/ml, respectively. Killing effect of RPE against a representative isolate V. cholerae PSU6072 was dose− and time−dependent. Transmission electron microscopy (TEM) showed that RPE effect V. cholerae cell morphology, as well as loss of cell wall were observed. At sub−MIC, RPE could reduce the swimming motility, decrease biofilm formation and disperse pre−formed biofilm of V. cholerae PSU6072. A significant down regulation of genes involved in V. cholerae quorum sensing regulator (luxO), swimming motility (flaA), and biofilm formation (vpsL, vpsR, bap1, and rbmA) was observed. In addition, a marked decrease in total aerobic bacteria and Vibrio spp. was found in shrimp meat after treatment with the RPE for short period (3 min). Thus, the results of present study strengthen the potential applications of RPE as anti−bacterial and anti−biofilm agents against V. cholerae and other bacteria contaminated in shrimp.

Study on Oxy-Methane Flame Stability in a Cylindrical Porous Medium Burner

Combustion in a porous medium can be beneficial for enhancing reaction rate and temperature uniformity. Therefore, considering the combination with oxy-fuel combustion can address some shortcomings in oxy-fuel burners, a cylindrical two-layer porous burner model is established based on OpenFOAM in this paper. A two-temperature equation model is adopted for the simulation of the heat transfer process. The CH4 skeletal kinetic mechanism is adopted for complex chemistry integration based on OpenSMOKE++. Corresponding experimental methods were used for complementary studies. The walls of the burner are wrapped with three types of thermal insulation materials to present different levels of heat loss. The results show that considering the convection and radiative heat loss of the burner wall, the temperature near the wall is reduced by more than 300 K compared to the adiabatic condition. As a result, the flame propagation speed and CO oxidation rate slowed down. The stable range will be destructively narrowed by more than 50%, and CO emissions will increase by more than 10 times. These defects will be aggravated by increasing the diameter of the burner. It is observed that when the diameter of the burner increases from the initial 5 cm to 10 cm, the effect of heat loss on the stable range is insignificant.

Transient flank bulge after percutaneous nephrolithotomy

Introduction: Percutaneous nephrolithotomy (PCNL) is considered as the “gold standard” treatment for large (&gt;2 cm) and complex kidney stones. We present a case of transient tone loss of the anterolateral abdominal wall, which is a rare complication after PCNL. Case Report: A 50-year-old male with a complete staghorn stone of the right kidney underwent standard PCNL in prone position at the 11th intercostal space. On the 6th post-operative day the patient complained on painless bulge in the right flank. Computed tomography (CT) scan in supine position revealed no signs of herniation, retroperitoneal hematoma, or residual fragments. Flank bulge was attributed to the muscle tone loss either because of the 11th intercostal nerve injury by the needle or nerve compression by the Amplatz sheath. Within next six months flank bulge has completely resolved. Conclusion: Flank bulge after PCNL although rare but possible and transient condition. Nerve injury seems to be the most likely cause.

Bacteria can shed a layer when phages turn up the heat.

Phage-encoded endolysins released from neighbouring infected bacterial cells can confer a temporary resistance to phage infection by mediating the reversible loss of the cell wall.

The effect of axial boundary conditions on breakout noise from finite cylindrical ducts

Ductborne noise within HVAC and exhaust systems may transfer into the surrounding environment through the walls of the duct. This breakout noise normally needs to be lowered in order to meet health and safety guidelines. This means that the ability of the duct walls to lower breakout noise needs to be predicted during the design stage of the duct systems. Significant work has been conducted into the prediction of breakout noise for infinite length ducts, however there is little to be found on finite length ducts. In particular there are very few studies on the difference between finite and infinite length duct breakout, especially where the noise source lies within the internal fluid. The aim of this work is therefore to investigate the difference in breakout noise between finite length and equivalent infinite length ducts when excited by an internal noise source. This is performed through numerical experiments using the semi analytical finite element method which enables the equations of elasticity for the duct wall, as well as a surrounding fluid, to be accommodated. Axial continuity equations at each end of a finite length elastic duct are then enforced through the point collocation method. It is observed that high sound power levels are emitted at axial resonances of the finite length duct. In the low frequency region these resonances have a narrow bandwidth and are expected to be of little practical significance. However, above the critical frequency the resonance bandwidth increases and this is observed to significantly lower the transverse transmission loss of the duct wall when compared to an infinite length duct. This phenomenon is observed for both clamped and simply supported ducts, as well as for two different internal sound sources. It is concluded that breakout noise from axial resonances in finite length ducts should be examined in design calculations in order to avoid excessive breakout noise.

Numerical study of the energy loss in the bulb tubular pump system focusing on the off-design conditions based on combined energy analysis methods

The unsteady flow characteristics of the low-head bulb tubular pump highly affects the operation efficiency and stability of the whole system. The purpose of this paper is to investigate the dominating loss area in a typical tubular pump using the combined energy analysis methods. The transient multi-condition flow through the pump system is simulated based on N–S equation integrating SST k-ω model. The power loss characteristics of each flow passage component are analyzed in terms of total pressure variation, entropy production and energy balance equation. The turbulent entropy generation power (PSD') in the entropy production and the turbulent kinetic energy production (PL3) of the energy balance equation are the primary source of power loss, indicating that the fully developed turbulent flow tends to generate considerable loss in the pump system, followed by the power loss of solid wall (PSW and PLW). The distribution of power loss in the impeller and diffuser was comprehensively exhibited and it was found that the undesirable flow patterns are mainly caused by blades and walls. The rim region in impeller domain with volume fraction of 15% induces the energy loss of approximately 45% due to the presence of solid wall and tip leakage vortex (TLV). Furthermore, the individual grid volume is considered to better locate and visualize regions with our great interest, and a number of typical vortex structures are identified under several flow rates showing that the positive attack angle is more likely to caused flow instability and energy loss at low flow rate condition.

Rotational labial and inferior pudendal artery based inner thigh flaps for vaginal defect after reconstructive surgery

For vaginal reconstructive surgery, the vaginal defect sometimes cannot be closed with primary intention due to poor tissue quality or loss of the vaginal wall. To cover the defect, plastic surgeons may be consulted with regard to a tissue advancement flap, a very complex procedure, and urologists may not feel familiar with it or comfortable with carrying it out. The rotational labial and inferior pudendal artery based inner thigh flap, devised by Professor Shlomo Raz, is a simple and useful procedure which urologists can perform with a short learning curve. Therefore, this article aims to demonstrate the surgical technique involved in this flap which can be widely used as an adjunct to any vaginal reconstructive procedures.

Longevity of stainless steel crowns as interim restorations on young permanent first molars that have undergone vital pulp therapy treatment in children and factors associated with their treatment failure: A retrospective study of up to 8.5 years.

Although stainless steel crowns (SSCs) on permanent molars are a common interim full-coverage restoration, there are few clinical studies on longevity. To evaluate the longevity of SSCs as restorations on young permanent first molars (PFMs) that have undergone vital pulp therapy (VPT) treatment and to identify factors associated with SSC treatment failure. This study conducted a retrospective chart review of children who had PFMs that have undergone VPT treatment and been restored with SSCs. Data from treatment and follow-up visits were collected. The Kaplan-Meier survival analysis was used to analyse the longevity of SSCs. A multivariate Cox proportional hazards regression model was used to identify factors associated with SSC treatment failure. Data from 140 SSCs were included, with an average follow-up period of 33.5 ± 21.6 (range, 6-104) months. Although none of the teeth had pulpal failure, 35.7% had SSC treatment failure. The survival probabilities of SSCs declined over time, reaching 39.6% (95% CI 27.0-51.9) after 60 months. The immediate post-operative condition of SSCs and the loss of proximal wall on the abutment tooth were significant factors associated with SSC treatment failure. Stainless steel crowns are suitable for use as interim restorations in PFMs that have undergone VPT treatment in children, but their longevity is limited, necessitating replacement over time.

Immediate implants in maxillary anterior region with guided bone augmentation

Aim: This case is a combination of vertical and horizontal defect in maxillary anterior region accompanied with absence of facial soft tissue which rehabilitated following extraction of tooth was rehabilitated by guided bone regeneration (GBR) and immediate implant Background: Loss of the labial bony wall during extraction of maxillary anterior teeth is a commonly encountered conundrum. During planning for an immediate implant placement in such a compromised area, guided bone regeneration (GBR) is a well-accepted method for bone and soft tissue reconstruction. Case Description: In the presented case report, a combination of vertical and horizontal defect of more than 2 mm accompanied with absence of facial soft tissue following extraction of tooth was rehabilitated by GBR and immediate implant. The follow - up was performed 36 months after final loading with good esthetic outcome and bone graft well apposed to native bone in CBCT evaluation with no obvious complications. Conclusion: The vertical and horizontal ridge volumetric alterations positively can be achieved by simultaneous GBR with immediate implant placement. Clinical Significance: The purpose of discussing this case report is to portray the efficacy of GBR along with immediate implant in case with both vertical and horizontal bone defects.

Contribution of vascular smooth muscle cell apoptosis to spiral artery remodeling in early human pregnancy.

Uterine spiral artery remodeling is one of the key maternal adaptations of pregnancy, allowing delivery of the large volumes of maternal blood required for both placental and fetal growth. Failure of this process is associated with obstetric complications including preeclampsia, fetal growth restriction and miscarriage. Spiral artery remodeling is characterized by loss of the musculoelastic wall which is replaced by fibrinoid and intramural extravillous trophoblast cells (EVT). In recent years attention has focused on the initial stages of spiral artery remodeling which include separation of the vascular smooth muscle cells (VSMCs) and their phenotypic switch to a more synthetic phenotype, facilitating their migration away from the vessel wall. However, less is known about the final fate of the VSMCs. In vitro studies suggested that EVT could induce VSMC apoptosis, though VSMC apoptosis is not seen within the wall of the spiral arteries undergoing remodeling. However, apoptotic VSMCs have been observed amongst those cells which had migrated away from the vessel wall. This review article gives a brief overview of the current state of knowledge of the processes involved in spiral artery remodeling, and then concentrates on the mechanisms involved in VSMC apoptosis, drawing on knowledge from other vascular beds.