Processing of Porous Hydroxyapatite Scaffold

Hydroxyapatite ceramics have been recognized as substitute materials for bone and teeth in orthopaedic and dentistry field due to their chemical and biological similarity to human hard tissue. It is biocompatible and bioactive material that can be used to restore damaged human calcified tissue. Porous hydroxyapatite exhibits strong bonding to the bone, the pores provide a mechanical interlock leading to a firm fixation of the material. Porous hydroxyapatite is more resorbable and more osteoconductive than its dense counterpart and in porous form the surface area is greatly increased which allows more cells to be carried in comparison with dense hydroxyapatite. The HA prepared from CaNO34H2O and (NH4)2HPO4 by co-precipitation method was phase pure at temperature 12500C. Porous scaffold was prepared by polymeric sponge and incorporation of fugitive such as naphthalene and PEG. Porous HA prepared from polymeric sponge method had about 70% porosity having pore diameter~400-500μm and pores were interconnected. With increase in PVA contents from 2 to 5 wt% with 40% solid loading the strength of the scaffold increased from 0.69-1.02MPa. It was studied that porosity, pore size and pore inter connectivity depends upon the slurry concentration and the amount of pore former used. In HA-PEG scaffold the porosity increased with PEG 4000 content, while it is decreased for PEG 6000 and pore size depends upon the molecular weight of PEG. In HA-naphthalene scaffold the porosity increased with increased the amount of pore former. It was observed that range of porosity~1-100μm obtained by varying the amount and size of ceramic and PEG particles. The molecular weight of PEG plays an important role in the morphology, structure, and pore size of scaffold. In-vitro bioactivity and biodegradability studies show that the synthesized scaffold from various methods was bioactive as well as bioresorbable

Hydroxyapatite Nanoparticles and Nanobiocomposite Scaffold for Protein Adsorption and Release

Spherical, rod and fibrous hydroxyapatite (HA) nanoparticles synthesize through a common co-precipitation technique and fabricate macroporous HA-gelatin nanobiocomposite scaffolds for protein adsorption/release study. Three fundamental processing parameters such as solution pH, temperature and Ca/P ratio synchronize the morphology and crystallinity of nano HA from identical precursors Ca(CH3COO)2 and KH2PO4. Dispersion study illustrates the HA nanoparticle suspension stability phenomenon in aqueous media. Rod shaped HA exhibits relatively better bovine serum albumin (BSA) protein adsorption efficacy with compare to other two morphologies. In aqueous media, one gram nanorod HA particle adsorb 28 mg BSA within a time frame of 48 h and subsequently 75 wt.% release after 96 h in phosphate buffer solution. Low temperature freeze casting of homogenous aqueous slurry of HA nanoparticles, gelatin and biocompatible polyvinyl alcohol binder develops nano HA – gelatin nanobiocomposite macroporous scaffolds. Freeze casted nanorod HA-gelatin macroporous (70 vol.%) scaffold demonstrate highest yield compressive strength of ~2 MPa compare to other scaffolds prepared from spherical and fibrous HA because of high surface area and the effective anchoring. An optimum cryogenic treatment time at 77K promotes the mechanical response of this low strength scaffold and designates as cryo-treated hydroxyapatite–gelatin macroporous scaffold (CHAMPS). CHAMPS has a high degree of interconnected pores of 50-200 μm in size, compressive strength up to 5.6 MPa and larger strain failure up to 25%. L929 mouse fibroblast cell interaction supports the cytotoxicity and cell adherence behaviour with CHAMPS. Porous scaffold exhibits bioactivity in simulated body fluid (SBF) solution through preferable deposition of carbonated apatite layer around the pores. Biodegradation of scaffold in tris-HCl solution reveals a slow but systematic decrease in weight over incubation up to 7 days. Importantly, the excellent adsorption (upto 50 wt.%) and release (upto 60 wt.% of adsorbed protein) of BSA within 48 h has been uniquely attributed to the inherent porous microstructure of the CHAMPS. Protein adsorption behaviour for both of the particles and scaffolds follow the classical Langmuir isotherm. The extensive micro-computed tomography (micro-CT) analysis establishes cancellous bone-like highly interconnected and complex porous architecture of the protein loaded and original CHAMPS. Overall, the present study provides an assessment of the interaction of protein with HA nanoparticles and their cryotreated HA-gelatin scaffold in vitro to support as drug delivery media and tissue engineering, respectively

Robotic Partial Nephrectomy with the Da Vinci Xi

Purpose. The surgical expertise to perform robotic partial nephrectomy is heavily dependent on technology. The Da Vinci Xi (XI) is the latest robotic surgical platform with significant advancements compared to its predecessor. We describe our operative technique and experience with the XI system for robotic partial nephrectomy (RPN). Materials and Methods. Patients with clinical T1 renal masses were offered RPN with the XI. We used laser targeting, autopositioning, and a novel “in-line” port placement to perform RPN. Results. 15 patients underwent RPN with the XI. There were no intraoperative complications and no operative conversions. Mean console time was 101.3 minutes (range 44–176 minutes). Mean ischemia time was 17.5 minutes and estimated blood loss was 120 mLs. 12 of 15 patients had renal cell carcinoma. Two patients had oncocytoma and one had benign cystic disease. All patients had negative surgical margins and pathologic T1 disease. Two postoperative complications were encountered, including one patient who developed a pseudoaneurysm and one readmitted for presumed urinary tract infection. Conclusions. RPN with the XI system can be safely performed. Combining our surgical technique with the technological advancements on the XI offers patients acceptable pathologic and perioperative outcomes

Fabrication, bioactivity, in vitro cytotoxicity and cell viability of cryo-treated nanohydroxyapatite–gelatin–polyvinyl alcohol macroporous scaffold

Freeze casting and cryogenic treatment both low temperature process have been employed to fabricate nanobiocomposite hydroxyapatite (HA)–gelatin–polyvinyl alcohol (PVA) macroporous scaffolds from synthesized three different spherical, rod and fibrous HA nanoparticles and composition optimized vis-á-vis porosity architecture, content and compressive strength. A critical HA morphology, solid loading and liquid nitrogen interaction time have a significant effect to enhance the mechanical response of developed scaffolds. Cryo-treated 40 wt.% nanorod HA–gelatin–PVA scaffold posses interconnected pore structure with 80 vol.% porosity, average pore diameter 50–200 μm and highest 5.8 MPa compressive strength. Different degree of the apatite deposition phenomenon in simulated body fluid solution at 37 °C and pH ∼ 7.4 varies with respect to time. In vitro cytotoxicity and L929 mouse fibroblast cell culture in the presence of Dulbecco's Modified Eagle Medium and 10% Fetal Bovine Serum at 37 °C and 5% CO2 atmosphere exhibit excellent cytocompatibility and cell viability at low extract concentration up to 25%

Study of BSA protein adsorption/release on hydroxyapatite nanoparticles

•Morphology, Ca:P and crystallinity have influence on protein adsorption.•BSA adsorption on HA nanoparticle follows Langmuir isotherm.•BSA protein secondary structure remains unchanged for BSA–HA conjugates.•One gram HA nanorod adsorbs 28mg BSA protein for 24h.•BSA loaded HA releases 75wt% BSA in the period of 96h. Three different spherical, rod and fibrous morphologies of hydroxyapatite (HA) nanoparticles have been prepared through control over the processing parameters like temperature, pH and Ca:P ratio. Protein adsorption/release with respect to HA nanoparticle morphologies are investigated using model protein bovine serum albumin (BSA). BSA adsorption on HA nanoparticles follows Langmuir adsorption isotherm. Thermal analysis and FT-IR spectrum confirms the BSA adhesion and retention of their secondary structure. High surface area with high Ca:P ratio nanorod adsorbs relatively more amount (28mg BSA/gm of nanorod HA) of BSA within 48h in comparison with counterpart fibroid and spherical morphologies. Slow and steady BSA release (75wt% of adsorbed BSA in 96h) from nanorod HA is found as futuristic drug delivery media

Pelvic lipomatosis: Bladder sparing extirpation of pelvic mass to relieve bladder storage dysfunction symptoms and pelvic pain

Pelvic lipomatosis is a rare benign disease, associated with overgrowth of fat in the perivesical and perirectal area. It is of unknown etiology. We describe a 45–year–old male with pelvic lipomatosis causing bladder storage dysfunction symptoms and pelvic pain that affected his quality of life. Surgical excision of the pelvic mass with bladder preservation was performed. After surgery, the patient had a marked improvement in his quality of life, with resolution of bladder storage dysfunction symptoms and pelvic pain

Fabrication of porous hydroxyapatite scaffold via polyethylene glycol-polyvinyl alcohol hydrogel state

[Display omitted] •High strength macroporous HAp scaffold fabricated via PEG–PVA hydrogel.•HAp scaffold has 70vol.% porosity, pore diameter ∼100μm and strength ∼4.2MPa.•The hydrogel results due to molecular interpenetration between PEG–PVA.•Weight of PEG plays vital rule for developing porosity in HAp matrix. Hydroxyapatite (HAp) ceramic was prepared from Ca(NO3)2 4H2O and (NH4)2HPO4 by co-precipitation method and HAp phase was stabilized up to 1250°C. Porous HAp scaffold was fabricated by using polyethylene glycol (PEG) cross linked with polyvinyl alcohol (PVA). The fabricated scaffold has 70vol.% porosity with strength 4.2MPa and the major fraction of pores were found within the range ∼70–100μm diameter obtained by varying the amount and size of ceramic and PEG particles. XRD, FT-IR, SEM and mercury porosimeter techniques were used to study the phase purity, pore size and pore size distribution of scaffold. The molecular weight of PEG plays an important role in the morphology, microstructure, and pore size of scaffold. In-vitro bioactivity of the fabricated scaffold was studied in SBF (simulated body fluid) at pH ∼7.4 and 37°C

Cryogenically cured hydroxyapatite-gelatin nanobiocomposite for bovine serum albumin protein adsorption and release

This research paper presents the first results on the protein adsorption and release kinetics and in vitro biodegradability of cryogenically cured hydroxyapatite-gelatin based micro/macroporous scaffolds (CHAMPS). While the adsorption and release of bovine serum albumin (BSA) protein exhibits steady state behavior over an incubation period of up to 10 days, Fourier transform infrared (FT-IR) analysis importantly confirms the absence of any change in the secondary structure of BSA proteins due to interaction with the CHAMPS scaffold. The compression properties of the CHAMPS scaffold with interconnected porosity (pore size similar to 50-200 mm) is characterized by a non-linear stress-strain response with a strength close to 5 MPa and a maximum strain of up to 24%. The slow but systematic increase in weight loss over a period of 7 days as well as apatite layer formation indicates its good bioactivity. The extensive micro-computed tomography (micro-CT) analysis establishes cancellous bone-like highly interconnected and complex porous architecture of the CHAMPS scaffold. Importantly, the excellent adsorption (up to 50%) and release (up to 60% of adsorbed protein) of BSA has been uniquely attributed to the inherent porous microstructure of the CHAMPS scaffold. Overall, the present study provides an assessment of the interaction of protein with the gelatin-hydroxyapatite macroporous scaffold in vitro, as well as reporting for the first time the efficacy of such scaffolds to release 60% of BSA loaded onto the scaffold in vitro, which is significantly higher than earlier literature reports

Rarely Described Renal Malignancies Associated With Venous Tumor Thrombus

Collecting duct carcinoma, epithelioid angiosarcoma and neuroendocrine/carcinoid tumor are uncommon renal malignancies, and their association with tumor thrombus extending into the inferior vena cava is extremely rare. Owing to the rarity of the above-mentioned malignancies and short follow-up of the cases published in the literature, the prognosis and clinical behavior of these tumors remains unclear. Up to date, the culprit of treatment is surgical management with radical nephrectomy, lymph node dissection, thrombectomy and vascular reconstruction if necessary. We herein describe in detail the first cases published of the above-mentioned renal malignancies associated with extensive inferior vena cava (IVC) thrombus, in which complex vascular reconstruction was performed. Three male patients were identified as having collecting duct carcinoma, epithelioid angiosarcoma and neuroendocrine/carcinoid tumor with IVC involvement. Tumor thrombus levels were II, I and IIIc respectively. Patient ages were 42, 60 and 47 years and tumor sizes were 9.2, 10.9 and 3.7 cm correspondingly. Patient 2 underwent cavectomy, IVC replacement using polytetrafluoroethylene (Gore-Tex ) vascular graft and IVC filter deployment inside the graft. None of the patients developed any pulmonary emboli postoperatively. At the last follow-up, IVC graft for patient 2 remained patent. Owing to the rarity of the aforementioned malignancies and short follow-up of cases published in the literature, the prognosis and clinical behavior of these tumors remains unclear. Up to date, the culprit of treatment is surgical management with radical nephrectomy, lymph node dissection, thrombectomy and vascular reconstruction if necessary. Polytetrafluoroethylene (Gore-Tex) vascular grafts are an excellent and safe option for complex vascular reconstructions in patients with evidence of IVC invasion

Primary synovial sarcoma of kidney: A rare tumor with an atypical presentation

Synovial sarcoma (SS) is a tumor of the soft tissues with a unique chromosomal translocation t(X;18)(p11.2;q11.2) that can be detected by polymerase chain reaction in tissue homogenates. Here we present a case of a 20-year-old female presenting PSS of the left kidney with caval thrombus. The diagnosis was corroborated by reverse transcription polymerase chain reaction (RT-PCR). Similar cases of PSS of kidney with tumor extension in the inferior vena cava are extremely rare and to date, approximately three cases have been reported in the literature