Hydrophilic Polyacrylamide Gel Research Articles

Treatment of Obstructive Sleep Apnea-Hypopnea Syndrome With a Mandible Advanced Device Increases Nitric Oxide Release and Ameliorates Pulmonary Hypertension in Rabbits

To investigate the effects of mandible advanced device (MAD) therapy for obstructive sleep apnea-hypopnea syndrome (OSAHS) on nitric oxide (NO) release and changes in pulmonary artery pressure and structure. Thirty male New Zealand white rabbits were randomly divided into OSAHS, MAD, and control groups (n=10 per group). The soft palate of rabbits in the OSAHS and MAD groups was injected with hydrophilic polyacrylamide gel to induce OSAHS. The MAD group wore a MAD, and the control group was not treated. Cone-beam computed tomography scans and polysomnography recordings were performed to confirm successful model establishment. All rabbits slept in a supine position for 4 to 6hours daily and were observed for 8 consecutive weeks. The pulmonary artery pressure was measured by right heart catheterization. Pulmonary artery morphometry was analyzed by hematoxylin and eosin staining. NO levels in plasma and lung homogenate supernatants were detected by Griess reaction assay kits. The OSAHS group exhibited higher pulmonary artery pressure (57.74±1.79mm Hg) than the MAD (19.99±2.04mm Hg) and control (14.49±0.54mm Hg) groups. The media thickness percentage of the pulmonary artery was higher in the OSAHS group (46.89±2.72%) than the control group (15.87±1.18%) and was markedly reduced by MAD (21.64±1.45%). Blood oxygen saturation was positively correlated with the NO concentration in both the lung and plasma, and the NO concentration was negatively correlated with the media thickness percentage and media section percentage. OSAHS induced a decrease in NO and pulmonary hypertension, which was relieved by MAD therapy.

Mandibular Advancement Devices Prevent the Adverse Cardiac Effects of Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS)

Although considerable research highlights the interactions between obstructive sleep apnea-hypopnea syndrome (OSAHS) and cardiovascular diseases, the effect of mandibular advancement device (MAD) treatment on cardiovascular complications in OSAHS patients remains unclear. We evaluated the effect of OSAHS treatment with MADs on the myocardium. All methods in this study were in accordance with relevant guidelines and regulations of the medical ethics committee in Hospital of Stomatology, Hebei Medical University approved the work. Thirty New Zealand rabbits were randomized into three groups: the control group, Group OSAHS, and Group MAD. Hydrophilic polyacrylamide gel was injected into the soft palate of the rabbits to induce OSAHS. In Group MAD, a MAD was positioned after OSAHS induction. All animals were induced to sleep in a supine position for 4–6 h/day for 8 weeks. Echocardiography was used to determine the structure and function of the heart. The histological changes were detected by optical microscopy and transmission electron microscopy (TEM). The levels of ET-1(endothelin-1) and Ang II (Angiotensin II) in the plasma were measured by an enzyme-linked immunosorbent assay (ELISA). The expression of ET-1 mRNA in heart tissue was detected by RT-PCR. Histological abnormalities, left ventricular hypertrophy, and left ventricular dysfunctions were demonstrated in Group OSAHS, and the abnormities were rescued with MAD treatment. Higher levels of plasma ET-1 and Ang II and elevated expression of ET-1 mRNA in cardiac tissue were detected in Group OSAHS compared with Group MAD and the control group. The blood oxygen saturation was negatively correlated with the levels of ET-1 and Ang II. OSAHS-induced elevated levels of ET-1 and Ang II may be attributed to myocardial structural abnormalities and dysfunction. Early treatment of MADs may play an important role in preventing myocardial damage in OSAHS rabbit model.

Magnetic Resonance Imaging Of Patients With Complications From Polyacrylamide Hydrophilic Gel Injection For Facial Plasty

Objective: To investigate the magnetic resonance imaging (MRI) signal features and MRI appearance of common complications resulting from polyacrylamide hydrogel (PAHG) injection for facial plasty? Methods: MRI and clinical data of 42 patients treated by PAHG injection for facial plasty were retrospectively analyzed and the MRI features were compared with clinical data. All images were acquired using a SIEMENS Skyra 3.0T MR imaging unit. MR sequences, including FSE-T1WI, FSE-FS-T2WI, STIR and DWI, were acquired with an 8-channel brain coil. MRI slices through the maxillofacial region in the transverse, coronal and sagittal planes were analyzed. Results: PAHG in the facial region appears as a variety of shapes owing to the anatomical space where it is present. It appears as a low signal intensity on T1-weighted images, high signal intensity on T2-weighted images and fat saturation T2-weighted images (the best contrast is obtained on fat saturation T2-weighted images), and high signal intensity on DWI. Of a total of 42cases, induration was observed in 23 cases, hydrogel migration in 13 cases, secondary deformity in three cases, and infection in three case. Conclusions: MRI can provide diagnostic information for common postoperative complications of PAHG facial injection. It is an ideal examination method to diagnose postoperative complications of PAHG and to perform postoperative follow-up.

Acute Inflammatory Reaction Following Removal of Hydrophilic Polyacrylamide Gel

Hydrophilic polyacrylamide gel (PAAG), although not approved for use in the United States, has been used throughout the world as a permanent filler for aesthetic applications since the 1980s. Numerous articles and case reports have been published highlighting complications arising from its use. In this case report, we present a 54-year-old woman who presented for surgical consultation, requesting removal of previously injected polyacrylamide gel with subsequent silicone implant breast augmentation who experienced an acute reaction following attempted removal of the gel. This report reviews the current use, complications, and management of complications in patient’s previously injected with PAAG.

Treatment of obstructive sleep apnoea-hypopnea syndrome by mandible advanced device reduced neuron apoptosis in frontal cortex of rabbits.

To investigate effects of mandible advanced device (MAD) therapy for obstructive sleep apnoea-hypopnea syndrome (OSAHS) on the neuron apoptosis and acetylcholine esterase activity in frontal cortex. Thirty male New Zealand white rabbits were randomly divided into three groups (n = 10 in each group): group OSAHS, group MAD, and control group. Hydrophilic polyacrylamide gel was injected into soft palate of the animals to induce OSAHS in group OSAHS and group MAD. The group MAD animals wore MAD to relief the obstructiveness. The control group was not given any treatment. Computed tomography (CT) examination of the upper airway and polysomnography (PSG) recordings were performed in supine position. All rabbits were induced to sleep in a supine position for 4 to 6 hours every day and were observed for consecutive 8 weeks. The frontal cortices of three groups were dissected and the neuron apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and flow cytometry. Acetylcholine esterase (AchE) activity in the frontal cortex was measured by spectrophotometry. The group OSAHS exhibited high neuron apoptosis rate and low AchE activity than those of group MAD and control group. The blood oxygen saturation was negatively correlated with neuronal apoptosis rate and positively correlated with AchE activity. Applying MAD in OSAHS animals significantly improve the neuronal damage and function deficits by apnoea-hypoxia caused by narrowed upper airway. This study provided evidence that MAD therapy for OSAHS can significantly decrease neuronal apoptosis and increase AchE activity in the frontal cortex.

Unusual presentation of a late complication in a polyacrylamide gel-injected breast

Implant migration is a known complication of hydrophilic polyacrylamide gel (PAAG) mammoplasty. We report the case of a female patient with an undisclosed history of bilateral breast augmentation with PAAG injections 10 years ago. The patient presented with abdominal pain and rapid gel migration into the abdominal and pelvic walls after sneezing. Computed tomography and sonography were performed, but the results were inconclusive. The diagnosis of PAAG migration was not made until the patient complained of progressive shrinkage of her right breast and disclosed the history of PAAG mammoplasty. A subsequent magnetic resonance imaging study confirmed the diagnosis. Gel migration was successfully treated using endoscopic lavage and breast debridement. Familiarity with the radiological features of PAAG migration and a thorough examination of the patient's history are mandatory for the accurate diagnosis of this complication.

EFFECT OF CHANGE OF TISSUE INTERFACE STIFFNESS ON OSTEOGENIC DIFFERENTIATION OF RAT BONE MARROW MESENCHYMAL STEM CELLS

To investigate the effect of tissue interface stiffness change on the spreading, proliferation, and osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMSCs), and to find the suitable stiffness range for stem cell differentiation. Bone marrow of male Sprague Dawley rats (4 weeks old) were selected to isolate and culture BMSCs by whole bone marrow cell adherent method. The third generation BMSCs (1×105 cells/mL) were inoculated into the ordinary culture dishes covered with polyacrylamide hydrophilic gel (PA) which elastic modulus was 1, 4, 10, 40, and 80 kPa (cells seeded on PA), and ordinary culture dish (75 MPa extreme high elastic modulus) as control. Spreading of cells in different stiffness of PA was observed under light microscope. The elastic modulus values of 4, 10, and 40 kPa PA were selected as groups A, B, and C respectively; the ordinary culture dish (75 MPa extreme high elastic modulus) was used as control group (group D). Cell counts was used to detect the growth conditions of BMSCs, alkaline phosphatase (ALP) kit to detect the concentration of ALP, alizarin red staining technique to detect calcium deposition status, and real-time quatitative PCR technique to detect the expressions of bone gla protein (BGP), Runx2, and collagen type I mRNA. With increased PA stiffness, BMSCs spreading area gradually increased, especially in 10 kPa and 40 kPa. At 1 and 2 days after culture, the growth rate showed no significant difference between groups (P>0.05); at 3-5 days, the growth rate of groups B and C was significantly faster than that of groups A and D (P<0.05), but difference was not statistically significant between groups A and D (P<0.05); at 5 days, the proliferation of group C was significantly higher than that of group B (P<0.05). ALP concentrations were (53.69±0.89), (97.30±1.57), (126.60±14.54), and (12.93±0.58) U/gprot in groups A, B, C, and D respectively; groups A, B, and C were significantly higher than group D, and group C was significantly higher than groups A and B (P<0.05). Alizarin red staining showed that the percentages of calcium nodules was 20.07%±4.24% in group C; group C was significantly higher than groups A, B, and D (P<0.05). The expression levels of BGP and collagen type I mRNA were significantly higher in groups A, B, and C than group D, and in group C than groups A and B (P<0.05). The expression level of Runx2 mRNA was significantly higher in groups B and C than group D, and in group C than group B (P<0.05), but no significant difference was found between groups A and D (P>0.05). PA elastic modulus of 10-40 kPa can promote the proliferation and osteogenic differentiation of BMSCs, and the higher the stiffness, the stronger the promoting effect.

An animal model of obstructive sleep apnoea-hypopnea syndrome corrected by mandibular advancement device.

The aim of the study is to establish a stable animal model of obstructive sleep apnoea-hypopnea syndrome (OSAHS) and assess the effectiveness of a mandibular advancement device (MAD). Eighteen 6-month-old male New Zealand white rabbits were randomized into three groups according to intervention: Group OSAHS, Group MAD, and a control group (n = 6 for each group). Rabbits in Group OSAHS and Group MAD were established as OSAHS model by injection, at a dose of 2 ml hydrophilic polyacrylamide gel, in the submucous muscular layer of the soft palate. Computed tomography (CT) and polysomnography (PSG) showed that OSAHS was developed successfully, the rabbits in Group MAD were fitted with the MAD and CT of the upper airway and PSG evaluated its effectiveness. Histological observation of the injection sites was conducted. CT scans showed the reduced sagittal space and cross-sectional areas of retropalatal upper airway in Group OSAHS were corrected by MAD (upper airway space in Group MAD was similar to that in the control group). The rabbits in Group OSAHS developed obvious sleep apnoea and hypopnea in supine position, with increased apnoea-hypopnea index and decreased oxygen saturation (SaO2). These were significantly improved by MAD and apnoea and hypopnea were not observed. Histology of the soft palate showed that the injected gel was entirely surrounded with connective tissues. We primarily developed an OSAHS and MAD therapy animal model with narrow oropharynx in upper airway which could be further available for OSAHS analysis.

Increased 131I Accumulation in the Polyacrylamide Hydrophilic Gel Used for Breast Augmentation

A 37-year-old woman with papillary thyroid cancer received repeat 131I therapy. The first posttherapy scan revealed only activity in the neck. However, both the second and third posttherapy scans showed intense activity in the anterior lower chest bilaterally, suggestive of breast uptake. However, the SPECT/CT images demonstrated that the iodine activity was not located in the breast tissue. Instead, the activity was inside the polyacrylamide hydrophilic gels she received 10 years ago for breast augmentation.

Magnetic resonance imaging of patients with polyacrylamide hydrophilic gel injection for facial plasty

Objective To investigate MRI signal features and MRI appearances of patients with advanced stage in polyacrylamide hydrophilic gel injection for facial plasty.Methods In this study,MRI of 11 cases with 23 polyacrylamide hydrophilic gel injection of facial plasty for 6 to 10 years were retrospectively reviewed.All images were acquired with GE 3.0T MR imaging unit.MR sequences,including FSE T1WI,FSE FS T2WI,and STIR were applied with 8-channel brain coil.MRIs sliced through the maxillofacial region in the transverse,coronal and sagittal planes.Results In 11 cases of 23 polyacrylamide hydrophilic gel injection,there were different degrees of capsule rupture and induration in 6 polyacrylamide hydrophilic gel injection,and the images showed sporadic callosities such as subcutaneous nodules and nodules in glands or muscles ; hydrogel migration in 8 polyacrylamide hydrophilic gel injection.Secondary deformity occured in 80 ％ cases,in which the most cases were induced by hydrogel migration.Conclusions Magnetic resonance imaging can make clear of the type of rupture and the distribution leakage of polyacrylamide hydrophilic gel for facial plasty and it is an ideal approach for advanced patients with polyacrylamide hydrophilic gel injection for follow-up. Key words: Magnetic resonance imaging; Polyacrylamide hydrophilic gel; Facial plasty; Complications

Aggregative properties of Rhodamine dyes in polyacrylamide hydrophilic gel media

The visible absorption spectra of two Rhodamine dyes (R6G and RB) in aqueous solutions, and in the polyacrylamide hydrogel matrix with different composition were studied at room temperature. The spectral properties of the dye-loaded hydrogel were also investigated. The transport and the solute–solute interactions of the ionic dyes in aqueous solutions across the hydrophilic gels were calculated. The monomer–dimer equilibrium of these ionic dyes in water and in different composition of hydrogel environment with different soaking time has been investigated by means of UV–Vis spectroscopy. The natures of the interacting pairs in these dyes were discussed using the Kasha exciton theory.

Breast Fibromatosis after Hydrophilic Polyacrylamide Gel Injection for Breast Augmentation: a Case Report and Review of the Literature

REAST fibromatosis is a rare kind of lesion. The average incidence is about 2-4 per million every year. So far there have been about 100 cases reported altogether. In this report, we describe a case of breast fibromatosis developed after hydrophilic polyacrylamide gel (HPG) injection for breast augmentation. By reviewing the literature, the possible pathogenesis of this case and the proper treatment strategy are investigated.

Mammaplasty after polyacrylamide hydrophilic gel removal from breast

To explore the relationship between mammaplasty and results after polyacrylamide hydrophilic gel (PAHG) removal from breast. From Feb. 2003 to Aug. 2009, 130 patients with bilateral breast augmentation by PAHG injection were treated. Preoperative ultrasound examination and MRI were performed to know the distribution of PAHG and infiltration at the surrounding tissue. According to the conditions after removal, the patients were received implant augmentation immediately, or at the second stage, or no implant. The patients were followed up for 3 months at the most with a very satisfactory rate of 63.84% (83/120), a satisfactory rate of 31.53% (41/120) and a unsatisfactory rate of 4.63% (6/120). Slight capsular contracture (Baker I) occurred in 5 cases with 6 breasts in satisfactory group. All the patients in unsatisfactory groups who selected unsuitable implants by themselves were re-operated to take out the implants. 3 cases with much residue PAHG insisted to receive breast implants. Among them, 2 cases achieved acceptable results even the surface of the breasts were not smooth. No other complication happened. The breast reaugmentation after PAHG removal should be performed based on the deformity and condition of breast. Both cosmetic result and psychological relief could be obtained after mammaplasty.

Effect of polyacrylamide hydrophilic gel composition on photo-physical behavior of Oxazine 750

Electronic absorption spectra of Oxazine 750 dye in aqueous solutions and in polyacrylamide hydrogel matrix with different structural composition were studied at room temperature. The transport and the solute–solute interactions of the ionic dye in aqueous solutions across the hydrophilic gels were investigated via exploring spectral properties of the dye-loaded hydrogel. The nature of the dye pair interactions in these media was discussed using the Kasha exciton theory. In addition, the monomer–dimer equilibrium of Oxazine 750 in hydrogels with different compositional percentage has been determined by means of UV–vis spectroscopy and least square fitting methods.

Correction of secondary breast deformities after removement of injected polyacrylamide hydrophilic gel

To investigate the correction of secondary breast deformities after removement of injected polyacrylamide hydrophilic gel (PAHG). From March 2003 to March 2008, 100 patients with bilateral breast augmentation with injected PAHG underwent operation to remove the PAHG. The age of patients ranged from 35 to 50 years. Ultrasound and MRI were performed before operation to show the distribution of PAHG and the muscle infiltration around the PAHG. According to the PAHG distribution, muscle infiltration, skin elasticity, infection and PAHG residue, the patients were treated respectively with breast implants at the same stage or at the second stage, or without implants. The patients were followed up for 3 months to 3 years. The percentage of satisfactory, median satisfactory and dissatisfactory was 90%, 9%, and 1%. In the median satisfactory group, 3 breasts in 3 cases showed slight capsular contracture (Baker II), 8 implants in 6 cases were palpable on the lower pole of the breasts. The middle-aged patient in dissatisfactory group was not satisfied with the high-projected implants shape which were chosen by herself and placed at the second stage. Then implants were removed. There was no complication of implant hernia, infection, wound disruption, or asymmetry. The secondary breast deformities could be corrected by breast augmentation with implants. Both breast appearance and the psychological affection can be improved.

Diagnostic cytological features of polyacrylamide gel injection augmentation mammoplasty

To study the cytological features of breast lesions associated with hydrophilic polyacrylamide gel (PAAG) injection augmentation mammoplasty and to determine the specific diagnostic features. Fine needle aspiration (FNA) cytology smears from 14 patients who presented with breast lump and a clinical history of PAAG injection were reviewed. The staining properties of the PAAG material in Papanicolaou (Pap), Haematoxylin and Eosin (H&E) and Diff-Quik stains, as well as the cellular background, were studied. Cell blocks were also studied with H&E, periodic acid-Schiff (PAS), periodic acid-Schiff with diastase digestion (PASD) and mucicarmine (MC) stains. PAAG was stained consistently pinkish with a homogenous smooth texture on H&E (100%), polychromasia on Pap (100%) and magenta violet with bubbly vacuoles on Diff-Quik (100%). Half (7) of the cases showed sharp borders. The presence of foreign body type giant cells with histiocytes (5 cases, 36%) and scanty clusters of benign ductal cells (4 cases, 29%) were seen in the background of a minority of the cases. PAAG was represented by blocks of homogenous grey-purplish acellular material with a sharp border on cell block sections, which were negative for PAS, PASD and MC. PAAG shows a consistent staining pattern in various common cytological staining preparations. Blocks of acellular gelatinous material, stained homogenous pinkish on H&E, polychromasia on Pap and magenta violet with bubbly vacuoles on Diff-Quik, are the reliable cytological features of PAAG.

Complications of Long-Lasting Facial Fillers

Introduction: Although facial fillers have been popular for years, some complications have been associated with their injection or inappropriate application. Because these products are so long lasting, such untoward consequences would be difficult or impossible to correct without surgical intervention. Despite the attractions that longevity and permanency offer, the long-term effects of injecting long-lasting fillers such as acryl pearls and polyacrylamide facial filler materials deserve serious consideration by both physicians and patients before injection treatment is initiated. The author presents in this article the results of his research into possible adverse reactions to facial fillers. Methods and Materials: A total of 110 patients were selected for this study, and each received an injection into a single location on the face. Ten patients were treated with Artecoll and 100 patients were treated with Dermalive (n = 50) and Dermadeep (n = 50). The injections were made in the glabella, nasolabial fold, lips, perioral, cheeks, and chin. To achieve a more accurate study result, injection into a single area of the face at a time was necessary. Results: Between 1992 and 2003, 57 patients presented with problems after acryl injections into the face. The granulomas caused by Artecoll were smaller and fewer than those caused by Dermalive and Dermadeep. Discussion: Two products that are relatively new to the esthetic treatment industry are poly-L-lactic acid, also known by the product names Sculptra in the United States and New-Fill in Europe, and hydrophilic polyacrylamide gel, known by the product names Bio-Alcamid, Amazingel, and Aqua-Mid. These materials also form granulomas. The ethical question about whether we as surgeons should implant materials into the face that we can never completely remove without damaging the surrounding healthy tissue should be discussed further. Conclusions: Permanent fillers that provide satisfactory results at first may become more visible or create an unnatural appearance as aging progresses. Because these products are so long lasting, such untoward consequences would be difficult or impossible to correct without surgical intervention. Given these problems, it is legitimate to question the necessity for such permanent fillers.

Radiological Appearance of Breast Augmentation with Injected Hydrophilic Polyacrylamide Gel

Radiological Appearance of Breast Augmentation with Injected Hydrophilic Polyacrylamide Gel

Calcium Inhibition of Polyacrylamide Gel Hydration Is Partially Reversible by Potassium

Hydration of a commercial hydrophilic polyacrylamide gel in 20 meq Ca(NO3)2/liter was reduced to &lt;10% of the maximum hydration in deionized water. Repeated soaking with deionized water to remove soluble salts restored hydration to ≈ 30% of maximum. Incorporating KNO3 at concentrations ranging from 5 to 40 meq·liter-1 with the Ca(NO3)2 in the hydration solution partially reversed the Ca2+ inhibition of hydration following repeated soaking. Potential hydrogel hydration increased to 50% of maximum with 40 meq K+/liter. Potassium nitrate supplied separately following hydration in Ca(NO3)2 was much more effective at reversing Ca2+ inhibition of hydrogel hydration than joint application. Potential hydrogel hydration (following repeated soaking) was doubled after treatment with 5 meq KNO3/liter and reached 77% of maximum at 40 meq KNO3/liter.

Biomimetic approach to the design of a pyridoxal enzyme model, 1. Hydrophilic polyacrylamide gel with stereochemically defined arrangement of salicylaldehyde and lysine fragments

AbstractA polymeric gel in which salicylaldehyde and lysine moieties are capable of forming an “internal” aldimine at pH &gt; 6,0 has been prepared by copolymerization of Nα‐5‐methacryloylaminosalicylidene‐Nε‐methacryloyl‐(S)‐lysinatocopper (II) (1a) with acrylamide and N,N'‐methylenebisacrylamide in water with subsequent removal of the copper ions by 0,1 M HCl or the disodium salt of EDTA. The equilibrium formation constants of the “internal” aldimine are ca. 30 times (at pH 7,1) and ca. 100 times (at pH 9,2) higher than the equilibrium constants of the model reaction of Schiff base formation from 5‐isobutyrylaminosalicylaldehyde (2) and Nt‐isobutyryl‐(S)‐lysine (3). The α‐amino group of the lysine residue in the gel acts as a nucleophilic catalyst in the reaction of the salicylaldehyde moiety of the gel with semicarbazide. The reaction proceeds 5,3 times faster in the gel than in a model polymeric system which does not contain lysine moieties.