Chitosan-Calcium-Simvastatin Scaffold as an Inductive Cell-Free Platform

The development of biomaterials based on the combination of biopolymers with bioactive compounds to develop delivery systems capable of modulating dentin regeneration mediated by resident cells is the goal of current biology-based strategies for regenerative dentistry. In this article, the bioactive potential of a simvastatin (SV)-releasing chitosan-calcium-hydroxide (CH-Ca) scaffold was assessed. After the incorporation of SV into CH-Ca, characterization of the scaffold was performed. Dental pulp cells (DPCs) were seeded onto scaffolds for the assessment of cytocompatibility, and odontoblastic differentiation was evaluated in a microenvironment surrounded by dentin. Thereafter, the cell-free scaffold was adapted to dentin discs positioned in artificial pulp chambers in direct contact with a 3-dimensional (3D) culture of DPCs, and the system was sealed to simulate internal pressure at 20 cm/H₂O. In vivo experiments with cell-free scaffolds were performed in rats' calvaria defects. Fourier-transform infrared spectroscopy spectra proved incorporation of Ca and SV into the scaffold structure. Ca and SV were released upon immersion in a neutral environment. Viable DPCs were able to spread and proliferate on the scaffold over 14 d. Odontoblastic differentiation occurred in the DPC/scaffold constructs in contact with dentin, in which SV supplementation promoted odontoblastic marker overexpression and enhanced mineralized matrix deposition. The chemoattractant potential of the CH-Ca scaffold was improved by SV, with numerous viable and dentin sialoprotein-positive cells from the 3D culture being observed on its surface. Cells at 3D culture featured increased gene expression of odontoblastic markers in contact with the SV-enriched CH-Ca scaffold. CH-Ca-SV led to intense mineralization in vivo, presenting mineralization foci inside its structure. In conclusion, the CH-Ca-SV scaffold induces differentiation of DPCs into a highly mineralizing phenotype in the presence of dentin, creating a microenvironment capable of attracting pulp cells to its surface and inducing the overexpression of odontoblastic markers in a cell-homing strategy.

Fibrin deposits and organ failure in newborn foals with severe septicemia

BACKGROUND

Septicemia in human neonates frequently is complicated by activation of the coagulation system, disseminated intravascular coagulation (DIC) and multiple organ failure syndrome, which may contribute to high mortality. In adult horses with DIC, the lung has been the organ most frequently affected by fibrin deposits. In addition, in vivo studies suggest that hemostatic mechanisms may be immature in foals < 1-day old.

HYPOTHESIS

Newborn foals with severe septicemia have fibrin deposits in their tissues independently of their age, and these fibrin deposits are associated with organ failure.

ANIMALS

Thirty-two septic and 4 nonseptic newborn foals euthanized for poor prognosis.

METHODS

Tissue samples (kidney, lung, and liver) collected on postmortem examination were stained with phosphotungstic acid hematoxylin (PTAH) and immunohistochemistry (IHC) for blind histologic examination. A fibrin score (grades 0-4) was established for each tissue sample and for each foal. Medical records were reviewed for assessing clinical evidence of organ failure during hospitalization.

RESULTS

Fibrin deposits were found in most septic foals (28/32 when using IHC and 21/32 when using PTAH), independently of the age of the foal. The lung was the most affected tissue (97% of the septic foals). Additionally, organ failure was diagnosed in 18/32 septic foals (8 with respiratory failure, 14 with renal failure), although a statistical association with severe fibrin deposition was not identified.

CONCLUSIONS AND CLINICAL IMPORTANCE

Nonsurviving septic foals have fibrin deposits in their tissues, a finding consistent with capillary microthrombosis and DIC.

Primary and secondary tumours occurring simultaneously in the brain of a dog

Primary brain tumours of a single histological type and metastatic brain tumours are well described in dogs in the current veterinary literature. However, the concurrent presence of a primary and secondary tumour in the brain of a dog has never, to the authors' knowledge, been previously reported. The clinical and pathological features of a nine-year-old, female boxer with an oligodendroglioma and metastases from a mammary gland adenocarcinoma occurring simultaneously in the brain are described in this case report. Information in the veterinary literature on multiple malignancies affecting the central nervous system is very limited; therefore, a discussion about comparative situations in human medicine has been included.

900-nm Nd:Ti:LiNbO(3) waveguide laser

We report what is to our knowledge the first laser operation of Nd(3+) -doped LiNbO(3) near 900 nm. An absorbed power threshold of 26 mW was obtained when the device was pumped at 814 nm. The design of the waveguide geometry to favor laser operation at this wavelength is demonstrated.

Tuberculous mesenteric lymphadenitis mimicking pancreatic carcinoma

Tuberculous mesenteric lymphadenitis is a rare clinical entity and non-surgical diagnosis of this condition remains a challenge. A 38-year-old Indian woman presented with a six-week history of epigastric pain, low-grade fever and anorexia. Upper endoscopy showed a gastric ulcer of the posterior wall of the stomach. On CT scan there was a 8 cm abdominal mass involving the pancreatic body and tail and the endoscopic ultrasonography was also compatible with a cystic pancreatic tumor which had eroded into the stomach. An exploratory laparotomy was performed and the diagnosis of tuberculous mesenteric lymphadenitis was confirmed by bacteriological and histological examinations. Medical therapy was started after surgery. At 18 months she is asymptomatic and abdominal CT scan is normal. Tuberculosis of mesenteric lymph nodes usually raises serious diagnostic problems. A high grade of suspicion is necessary in order to perform a pre-operative diagnosis.

Calcitonin-producing insulinoma: clinical, immunocytochemical and cytogenetical study

The case of a patient with a large goitre associated with hypercalcitoninaemia and fasting hypoglycaemia is reported. Pentagastrin (PG) test was negative. Repeated measurements of fasting glycaemia, insulin and C peptide established the diagnosis of insulinoma. After localization by endoscopic ultrasonography, a distal pancreatectomy was performed and a small insulinoma was recovered. Glycaemia and calcitonin (CT) became normal. The tumour cells displayed a strong immunoreactivity for insulin and CT. Cytogenetical evaluation of the tumour revealed a translocation t(1;9) (p13;p22).

Leiomyosarcoma of the esophagus

This report analyzes classification, frequency, and history of esophageal sarcomas and introduces a clinical case of leiomyosarcoma of the thoracic esophagus. The clinical, radiologic, endoscopic, pathologic, and therapeutic aspects of this unique case are presented and discussed.