Spatial control of bone formation using a porous polymer scaffold co-delivering anabolic rhBMP-2 and anti-resorptive agents.

Current clinical delivery of recombinant human bone morphogenetic proteins (rhBMPs) utilises freeze-dried collagen. Despite effective new bone generation, rhBMP via collagen can be limited by significant complications due to inflammation and uncontrolled bone formation. This study aimed to produce an alternative rhBMP local delivery system to permit more controllable and superior rhBMP-induced bone formation. Cylindrical porous poly(lactic-co-glycolic acid) (PLGA) scaffolds were manufactured by thermally-induced phase separation. Scaffolds were encapsulated with anabolic rhBMP-2 (20 µg) ± anti-resorptive agents: zoledronic acid (5 µg ZA), ZA pre-adsorbed onto hydroxyapatite microparticles, (5 µg ZA/2% HA) or IkappaB kinase (IKK) inhibitor (10 µg PS-1145). Scaffolds were inserted in a 6-mm critical-sized femoral defect in Wistar rats, and compared against rhBMP-2 via collagen. The regenerate region was examined at 6 weeks by 3D microCT and descriptive histology. MicroCT and histology revealed rhBMP-induced bone was more restricted in the PLGA scaffolds than collagen scaffolds (-92.3% TV, p < 0.01). The regenerate formed by PLGA + rhBMP-2/ZA/HA showed comparable bone volume to rhBMP-2 via collagen, and bone mineral density was +9.1% higher (p < 0.01). Local adjunct ZA/HA or PS-1145 significantly enhanced PLGA + rhBMP-induced bone formation by +78.2% and +52.0%, respectively (p ≤ 0.01). Mechanistically, MG-63 human osteoblast-like cells showed cellular invasion and proliferation within PLGA scaffolds. In conclusion, PLGA scaffolds enabled superior spatial control of rhBMP-induced bone formation over clinically-used collagen. The PLGA scaffold has the potential to avoid uncontrollable bone formation-related safety issues and to customise bone shape by scaffold design. Moreover, local treatment with anti-resorptive agents incorporated within the scaffold further augmented rhBMP-induced bone formation.

Sustained low-efficiency daily dialysis with hemofiltration for acute kidney injury in the presence of sepsis.

AIMS: Acute kidney injury (AKI) commonly occurs in critically ill patients with sepsis and is associated with poor outcomes. Unfortunately, the ideal mode of renal replacement therapy remains unknown. Because both higher doses of dialysis and hemofiltration have been associated with improved survival, we postulated that adding hemofiltration to the diffusive clearance achieved by sustained low-efficiency daily dialysis (SLEDD-f) would provide a survival advantage over SLEDD. METHODS: From December 2003 to October 2005, we retrospectively analyzed all patients with multisystem organ failure, vasopressor-dependent hypotension and oliguric acute kidney failure secondary to nonoperative sepsis who were treated with renal replacement therapy (RRT). After exclusionary criteria were applied, 8 patients received SLEDD-f and 13 patients received SLEDD. All treatments were for 8 - 16 h/day. SLEDD-f was continued until vasopressors were reduced to a minimal dose. Outcomes were mortality and recovery of renal function at 30 days after initiation of RRT. APACHE- II scores were calculated at the time of dialysis initiation to predict mortality. RESULTS: Despite higher APACHE II scores, 30-day survival was 100% in the SLEDD-f group and 38% in the SLEDD group. Furthermore, most of the SLEDD-f patients were able to have vasopressors weaned quickly and all patients in the SLEDD-f group recovered significant renal function to allow discontinuation of RRT. CONCLUSIONS: While the optimal treatment remains unknown, this small study raises the possibility that SLEDD-f offers a survival advantage and increases the chance of renal recovery while decreasing the need for vasopressors. A large randomized trial comparing SLEDD-f with other forms of renal replacement therapy is needed.

A double chamber rotating bioreactor for enhanced tubular tissue generation from human mesenchymal stem cells: a promising tool for vascular tissue regeneration.

Cardiovascular diseases represent a major global health burden, with high rates of mortality and morbidity. Autologous grafts are commonly used to replace damaged or failing blood vessels; however, such approaches are hampered by the scarcity of suitable graft tissue, donor site morbidity and poor long-term stability. Tissue engineering has been investigated as a means by which exogenous vessel grafts can be produced, with varying levels of success to date, a result of mismatched mechanical properties of these vessel substitutes and inadequate ex vivo vessel tissue genesis. In this work, we describe the development of a novel multifunctional dual-phase (air/aqueous) bioreactor, designed to both rotate and perfuse small-diameter tubular scaffolds and encourage enhanced tissue genesis throughout such scaffolds. Within this novel dynamic culture system, an elastomeric nanofibrous, microporous composite tubular scaffold, composed of poly(caprolactone) and acrylated poly(lactide-co-trimethylene-carbonate) and with mechanical properties approaching those of native vessels, was seeded with human mesenchymal stem cells (hMSCs) and cultured for up to 14 days in inductive (smooth muscle) media. This scaffold/bioreactor combination provided a dynamic culture environment that enhanced (compared with static controls) scaffold colonization, cell growth, extracellular matrix deposition and in situ differentiation of the hMSCs into mature smooth muscle cells, representing a concrete step towards our goal of creating a mature ex vivo vascular tissue for implantation. Copyright © 2016 John Wiley & Sons, Ltd.

Polyurethane/poly(lactic-co-glycolic) acid composite scaffolds fabricated by thermally induced phase separation.

In this study, we present a novel composite scaffold fabricated using a thermally induced phase separation (TIPS) process from poly(lactic-co-glycolic) (PLGA) and biomedical polyurethane (PU). This processing method has been tuned to allow intimate (molecular) mixing of these two very different polymers, giving rise to a unique morphology that can be manipulated by controlling the phase separation behaviour of an initially homogenous polymer solution. Pure PLGA scaffolds possessed a smooth, directional fibrous sheet-like structure with pore sizes of 0.1-200mum, a porous Young's modulus of 93.5kPa and were relatively brittle to touch. Pure PU scaffolds had an isotropic emulsion-like structure, a porous Young's modulus of 15.7kPa and were much more elastic than the PLGA scaffolds. The composite PLGA/PU scaffold exhibits advantageous morphological, mechanical and cell adhesion and growth supporting properties, when compared with scaffolds fabricated from PLGA or PU alone. This novel method provides a mechanism for the formation of tailored bioactive scaffolds from nominally incompatible polymers, representing a significant step forward in scaffold processing for tissue-engineering applications.

A new stapler-based full-thickness transgastric access closure: results from an animal pilot trial.

BACKGROUND AND STUDY AIMS: Reliable closure of the transluminal incision is the crucial step for natural orifice transluminal endoscopic surgery (NOTES) procedures. The aim of this study was to evaluate the feasibility and effectiveness of transgastric access closure with a flexible stapling device in a porcine survival model. PATIENTS AND METHODS: We carried out four experiments (two sterile and two nonsterile) on 50 kg pigs. The endoscope was passed through a gastrotomy made with a needle knife and an 18-mm controlled radial expansion dilating balloon. After peritoneoscopy, a flexible linear stapling device (NOLC60, Power Medical Interventions, Langhorne, Pennsylvania, USA) was perorally advanced over a guide wire into the stomach, positioned under endoscopic guidance, and opened to include the site of gastrotomy between its two arms; four rows of staples were fired. One animal was sacrificed 24 hours after the procedure (progression of pre-existing pneumonia). The remaining animals were survived for 1 week and then underwent repeat endoscopy and postmortem examination. RESULTS: Peroral delivery and positioning of the stapling device involved some technical difficulties, mostly due to the short length (60 cm) of the stapling device. The stapler provided complete leak-resistant gastric closure in all pigs. None of the surviving animals had any clinical signs of infection. Necropsy demonstrated an intact staple line with full-thickness healing of the gastrotomy in all animals. Histologic examination confirmed healing, but also revealed intramural micro-abscesses within the gastric wall after nonsterile procedure. CONCLUSIONS: Gastrotomy closure with a perorally delivered flexible stapling device created a leak-resistant transmural line of staples followed by full-thickness healing of the gastric wall incision. Increasing the length of the instrument and adding device articulation will further facilitate its use for NOTES procedures.

Development of an in-process UV-crosslinked, electrospun PCL/aPLA-co-TMC composite polymer for tubular tissue engineering applications.

UNLABELLED: Cardiovascular diseases remain the largest cause of death worldwide, and half of these deaths are the result of failure of the vascular system. Tissue engineering promises to provide new, and potentially more effective therapeutic strategies to replace damaged or degenerated vessels with functional vessels. However, these engineered vessels have substantial performance criteria, including vessel-like tubular shape, structure and mechanical property slate. Further, whether implanted without or with prior in vitro culture, such tubular scaffolds must provide a suitable environment for cell adhesion and growth and be of sufficient porosity to permit cell colonization. This study investigates the fabrication of slowly degradable, composite tubular polymer scaffolds made from polycaprolactone (PCL) and acrylated l-lactide-co-trimethylene carbonate (aPLA-co-TMC). The addition of acrylate groups permits the 'in-process' formation of crosslinks between aPLA-co-TMC chains during electrospinning of the composite system, exemplifying a novel process to produce multicomponent, elastomeric electrospun polymer scaffolds. Although PCL and aPLA-co-TMC were miscible in a co-solvent, a criteria for electrospinning, due to thermodynamic incompatibility of the two polymers as melts, solvent evaporation during electrospinning drove phase separation of these two systems, producing 'core-shell' fibres, with the core being composed of PCL, and the shell of crosslinked elastomeric aPLA-co-TMC. The resulting elastic fibrous scaffolds displayed burst pressures and suture retention strengths comparable with human arteries. Cytocompatibility testing with human mesenchymal stem cells confirmed adhesion to, and proliferation on the three-dimensional fibrous network, as well as alignment with highly-organized fibres. This new processing methodology and resulting mechanically-robust composite scaffolds hold significant promise for tubular tissue engineering applications. STATEMENT OF SIGNIFICANCE: Autologous small diameter blood vessel grafts are unsuitable solutions for vessel repair. Engineered solutions such as tubular biomaterial scaffolds however have substantial performance criteria to meet, including vessel-like tubular shape, structure and mechanical property slate. We detail herein an innovative methodology to co-electrospin and 'in-process' crosslink composite mixtures of Poly(caprolactone) and a newly synthesised acrylated-Poly(lactide-co-trimethylene-carbonate) to create elastomeric, core-shell nanofibrous porous scaffolds in a one-step process. This novel composite system can be used to make aligned scaffolds that encourage stem cell adhesion, growth and morphological control, and produce robust tubular scaffolds of tunable internal diameter and wall thickness that possess mechanical properties approaching those of native vessels, ideal for future applications in the field of vessel tissue engineering.

Stoichiometric control of live cell mixing to enable fluidically-encoded co-culture models in perfused microbioreactor arrays.

In vivo, tissues are maintained and repaired through interactions between the present (different) cell types, which communicate with each other through both the secretion of paracrine factors and direct cell-cell contacts. In order to investigate and better understand this dynamic, complex interplay among diverse cell populations, we must develop new in vitro co-culture strategies that enable us to recapitulate such native tissue complexity. In this work, a microfluidic mixer based on a staggered herringbone design was computationally designed and experimentally validated that features the ability to mix large, non-diffusive particles (i.e. live cells) in a programmed manner. This is the first time that the herringbone mixer concept has been shown to effectively mix particles of the size range applicable to live cells. The cell mixer allowed for sequentially mixing of two cell types to generate reverse linear concentration co-culture patterns. Once validated, the mixer was integrated into a perfused microbioreactor array as an upstream module to deliver mixed cells to five downstream culture units, each consisting of ten serially-connected circular microculture chambers. This novel cell mixer microbioreactor array (CM-MBA) platform was validated through the establishment of spatio-temporally tunable osteogenic co-culture models, investigating the role of pre-osteoblastic cells (SAOS2) on human mesenchymal stem cells (hMSCs) commitment to an osteogenic endpoint. An increase on expression of alkaline phosphatase in sequential (downstream) chambers, consistent with the initial linear distribution of SAOS2, suggests not only osteoblastic cell-driven hMSCs induction towards the osteogenic phenotype, but also the importance of paracrine signaling. In conclusion, the cell mixer microbioreactor array combines the ability to rapidly establish cell co-culture models in a high-throughput, programmable fashion, with the additional advantage of maintaining cells in culture under perfused medium to explore paracrine factor impacts, representing a promising new tool for directing multi-cellular tissue formation for tissue engineering applications.

Effects of electric fields on human mesenchymal stem cell behaviour and morphology using a novel multichannel device.

The intrinsic piezoelectric nature of collagenous-rich tissues, such as bone and cartilage, can result in the production of small, endogenous electric fields (EFs) during applied mechanical stresses. In vivo, these EFs may influence cell migration, a vital component of wound healing. As a result, the application of small external EFs to bone fractures and cutaneous wounds is actively practiced clinically. Due to the significant regenerative potential of stem cells in bone and cartilage healing, and their potential role in the observed improved healing in vivo post applied EFs, using a novel medium throughput device, we investigated the impacts of physiological and aphysiological EFs on human bone marrow-derived mesenchymal stem cells (hBM-MSCs) for up to 15 hours. The applied EFs had significant impacts on hBM-MSC morphology and migration; cells displayed varying degrees of conversion to a highly elongated phenotype dependent on the EF strength, consistent perpendicular alignment to the EF vector, and definitive cathodal migration in response to EF strengths ≥0.5 V cm(-1), with the fastest migration speeds observed at between 1.7 and 3 V cm(-1). We observed variability in hBM-MSC donor-to-donor responses and overall tolerances to applied EFs. This study thus confirms hBM-MSCs are responsive to applied EFs, and their rate of migration towards the cathode is controllable depending on the EF strength, providing new insight into the physiology of hBM-MSCs and possibly a significant opportunity for the utilisation of EFs in directed scaffold colonisation in vitro for tissue engineering applications or in vivo post implantation.

The natural history of bronchial atresia. Serial observations of a case from birth to operative correction.

A 10-year-old child presented with a history of intermittent respiratory symptoms since birth. Progressive shift of the mediastinum away from a hyperexpanded left upper lobe to the right side was evident on serial chest films, since birth. Bronchograms demonstrated atresia of the bronchus to the hyperexpanded segment. Xenon washout demonstrated prolonged half-time in the left upper lobe resulting from collateral ventilatory channels. Resection of the apical posterior segment of the left upper lobe was performed without complication. Bronchial atresia with collateral ventilation caused "lobar emphysema" in this patient.

Decortication for childhood empyema. The primary provider's peccadillo.

Of the 31 children treated for empyema thoracis secondary to pneumonitis at the Loma Linda University Medical Center, Loma Linda, Calif, from 1980 to 1990, 23 responded to prompt directed antibiotic therapy coupled with drainage, usually tube thoracostomy. All patients were cured clinically; some demonstrated residual pleural reaction with chest roentgenography or computed tomography that resolved over time. Decortication was necessary in eight severely ill children; three required concurrent lung resection for abscess. Distinct from the nonoperated group, there was a pattern of initial antibiotic trials in these patients averaging 6.5 different drugs plus delayed drainage of effusions. Delay in the initiation of antibiotic therapy was six times longer for the operated vs the nonoperated group. Delay to tube thoracostomy was 18 days for the decorticated children compared with 5.4 days for the nondecorticated children. All eight children responded completely and rapidly to their decortications. Roentgenographic changes lagged considerably behind the clinical course of the child, and computed tomographic scans provided better identification of chest tube placement but little information predictive of the need for decortication. Decortication for empyema seldom is necessary when a child is treated promptly with appropriate antibiotics directed by thoracentesis findings, and drainage, usually tube thoracostomy. The criterion for decortication is persistent sepsis, not the roentgenographic appearance of the chest.

Life-threatening respiratory distress from mediastinal masses in infants.

From 1972 through 1974, 5 infants with severe respiratory distress secondary to mediastinal tumors were treated in the Division of Pediatric Surgery of The Johns Hopkins thospital; The mediastinal masses included 2 intramural bronchial cysts, a giant esophageal duplication, a benign teratoma, and a highly malignant neuroblastomamindividualized management was carried out successfully in all: total resection of the bronchial cysts and teratoma; partial resection of the duplication cyst with stripping of the remaining mucosa from the contiguous esophageal wall, thereby preserving esophageal integrity; and excision of involved chest wall and tumor combined with radiotherapy and chemotherapy for the neuroblastoma. This experience emphasizes the potential for lethal respiratory distress from mediastinal tumors in infants and supports the experience reported by others of serious consequences if resection is not performed. Primary physicians and thoracic surgeons must be aware of the lethal potential of such mediastinal tumors among the many other "surgical" causes of respiratory distress in neonates and infants.

Treatment of cryptorchidism. Long-term prospective study.

We have presented preliminary findings on a long-term prospective study designed to (1) assess timing of orchiopexy, (2) eliminate unnecessary abdominal exploratory surgery, and (3) determine efficacy of orchiopexy on subsequent fertility and on malignant degeneration. Some suggestions for the management of this common congenital defect can be provided, but long-term results are lacking. A significant drop-out rate from this prospective study is expected with time; therefore, large patient numbers are needed to draw any valid conclusions at the time of postpubertal reassessment.

Who is my patient after my patient dies? Issues in organ procurement.

Organ donation, procurement, and transplantation have become commonplace events. When a person is dying, the attending physician's "patients" include not only the grieving family but also the many unknown persons awaiting an organ for transplantation. A regional transplant program can be immensely helpful to the attending physician, the hospital staff, and the family of the dying patient.

Effects of morphine on rat kidney glomerular podocytes: a scanning electron microscopic study.

Degenerative kidney changes are associated with heroin use in human addicts, but it is not known whether these changes result from exposure to the opioid or from contaminants in street heroin. In the present study, 4-6-month-old rats each received 1 subcutaneous pellet containing 75 mg of morphine or placebo, followed 3 days later by implantation of 2 additional morphine or placebo pellets. Seven days after implantation of the first pellet, the rats were killed by aldehyde perfusion. The right kidney was excised, and coronal slices were prepared for scanning electron microscopy. Micrographs were taken at 5000X and were scored on the presence of short or long microprojections (a score of '1' indicating few and a score of '4' indicating many). Morphine significantly altered the frequencies of scores for long microprojections, suggesting that morphine treatment increased the number of microprojections on glomerular podocytes. No changes in filtration slits, pedicels, or blebbing (foval enlargements) were noted. The data support the view that kidney degeneration associated with opioid abuse reflects effects of opioids per se, and they are consistent with microprojection changes as a function of altered intracellular cyclic AMP levels.

AIDS prevention struggles in ethnocultural neighborhoods: why research partnerships with community based organizations can't wait.

Community based AIDS prevention programming and research in minority neighborhoods are growing. The AIDS epidemic has demoralized many minority communities and has added to enormously stressing social conditions. Obstacles to effective AIDS prevention programming must be removed before stable, accessible, and culturally relevant services can be provided. A pilot study was conducted to identify the obstacles to AIDS research or intervention in ethnic minority neighborhoods. Twenty-nine administrators and counselors from Community Based Organizations completed questionnaires concerning reasons for entering the field of AIDS prevention, enjoyment of work, hopefulness towards AIDS efforts, priority of AIDS funding, and opinions about most and least helpful prevention efforts in minority communities. Barriers identified as most problematic include insufficient funds, lack of culturally relevant materials, denial of the epidemic in minority communities, distrust of majority culture institutions, and myths/beliefs regarding AIDS contraction, transmission, and origin. Future research ideas are identified to improve culturally relevant AIDS prevention interventions in ethnocultural neighborhoods.

DNA alterations in prostatic adenocarcinoma and benign prostatic hyperplasia: detection by DNA fingerprint analyses.

DNA fingerprinting can be utilized to examine a large number of autosomal loci throughout the human genome. Alterations in banding patterns observed on DNA fingerprint analyses reflect DNA alterations ranging from single base changes to complex chromosomal rearrangements. In this report, we describe the application of this technique to prostatic adenocarcinoma (CAP) and benign prostatic hyperplasia (BPH). The majority of CAP cases (12 of 14) displayed alterations in at least 1 of the approximately 30 resolvable bands obtained by fingerprint analyses when compared with DNA obtained from peripheral white blood cells. Unexpectedly, 5 of the 12 cases of BPH examined revealed at least 1 identifiable band alteration in the prostatic tissue. These findings demonstrate the usefulness of fingerprint analyses in the examination of cancer-associated genetic alterations. They also suggest the presence of observable genetic alterations in BPH.

Central line occlusion with three-in-one nutrition admixtures administered at home.

The use of single-container parenteral nutrition admixtures can be cost effective and can simplify home administration. Three-in-one admixtures (dextrose, amino acids, lipid emulsion, and other additives in a single bag) were in use when a marked increase in catheter occlusions was seen in the pediatric home parenteral nutrition population. Insoluble laminar deposits were found in the removed catheters. In all subsequently placed catheters, separate (SPLIT) infusions of lipid and parenteral nutrition solution were used rather than three-in-one admixtures. This was associated with an obvious decrease in catheter occlusions. Catheter life-span was retrospectively determined for 15 catheters of identical size and style that were used in eight patients who had received either infusions of three-in-one admixtures or SPLIT infusions. Life table survival analysis revealed a median survival time of 70 days for the three-in-one group (n = 8) and 290 days for the SPLIT group (n = 7). Survival distributions for the two groups were significantly different (p = .025). During the period of clustered catheter occlusion, the use of three-in-one admixtures that were stored in the home for up to 7 days was associated with a shortened catheter life-span. Occlusion or deposit development was not seen in catheters used for inpatient parenteral nutrition support when admixtures were prepared and infused within 28 hours. Catheter deposits were implicated as sanctuary sites for pathogenic bacteria in two patients. Failure to retrieve and inspect occluded catheters delayed the identification of the deposits.(ABSTRACT TRUNCATED AT 250 WORDS)

A critical analysis of blood transfusion requirements in children with blunt abdominal trauma.

Over the past 2 years, 178 children with blunt abdominal trauma were admitted for observation. Fifty-five patients (31.5%) had intra-abdominal injury confirmed by computerized tomography (CT) scan, laparotomy, or postmortem examination. Forty-four children (80%) were managed with observation only; nine had other operations. Eleven patients (20%) required an operation for their intra-abdominal injuries. Thirteen patients died, ten from head or spinal injuries and three from intra-abdominal injuries (5.5%). Of 35 children with intra-abdominal injuries observed without any type of operation, 27 (77%) were not transfused (mean Pediatric Trauma Score [PTS] 8, Injury Severity Score [ISS] 19.3, average low hemoglobin [ALH] 10.1). The other eight were transfused an average of 49 cc/kg (mean PTS 4.5, ISS 26.5 ALH 6.1). Twenty children had operations. Eleven 11 (20%) of these were laparotomies; nine were transfused an average of 200.6 cc/kg (mean PTS 6, ISS 33, ALH 9). Nine had neurosurgical/orthopedic procedures (mean PTS 6.2, ISS 27.7), with six transfusions averaging 84.9 cc/kg (ALH 8.9). There were no significant complications. Blood transfusion was necessary only for 33 per cent of the observed cases, usually with multiple injuries. Blood should be transfused only to maintain hemodynamic stability (normal vital signs and tissue perfusion). Hemoglobin levels as low as 7 gm% do not mandate transfusion in children who are hemodynamically stable.

Dynamics of water spreading on a glass surface.

The impact of a water droplet on a glass surface is studied experimentally using a high-speed video camera which can catch up to 60,000 images per second with an exposure time of 10 micros. A wide range of impact velocities are studied by varying the fall height, showing different spreading regimes. Particular attention is given to the dynamics of the contact angle and its relation to the maximum expanding radius and capillary number. A linear relation between the contact line velocity and the impact velocity is found experimentally. Using acoustic analysis, an evaluation of the pressure at the contact line is given. We also confront predicted and experimental jetting times. This work shows that descriptions of drop impact based purely on conservation of energy are inadequate to describe the dynamics of the event. The different shapes taken by the drops between the initial impact and the maximum radius determine the final outcome.

Ectopic gastric-like duplication of the pancreas.

A 4-month-old girl presented with intermittent left upper quadrant abdominal pain and was found to have an ectopic cystic gastric-like duplication attached to the tail of the pancreas. The literature, pathology, clinical features, diagnosis, and treatment are discussed.