Treatment monitoring of brain creatine deficiency syndromes: a 1H- and 31P-MR spectroscopy study

BACKGROUND AND PURPOSE: Brain creatine (Cr) deficiencies (BCr-d) are rare disorders of creatine biosynthesis and transport. We performed consecutive measures of total Cr (tCr) and of its phosphorylated fraction, phosphocreatine (PCr), in the brains of children affected by Cr synthesis defects during a long period of therapy. The aim was to identify the optimal treatment strategy for these disorders. MATERIALS AND METHODS: Two patients with guanidinoacetate methyltransferase defect (GAMT-d) were treated with different amounts of Cr and with diet restrictions aimed at reducing endogenous guanidinoacetate (GAA) synthesis. Three patients with arginine:glycine amidinotransferase defect (AGAT-d) were treated with different Cr intakes. The patients' treatments were monitored by means of (1)H- and (31)P-MR spectroscopy. RESULTS: Cr and PCr replenishment was lower in GAMT-d than in AGAT-d even when GAMT-d therapy was carried out with a very high Cr intake. Cr and especially PCr replenishment became more efficient only when GAA blood values were reduced. Adenosine triphosphate (ATP) was increased in the baseline phosphorous spectrum of GAMT-d, and it returned to a normal value with treatment. Brain pH and brain P(i) showed no significant change in the AGAT-d syndrome and at any Cr intake. However, 1 of the 2 GAMT-d patients manifested a lower brain pH level while consuming the GAA-lowering diet. CONCLUSIONS: AGAT-d treatment needs lower Cr intake than GAMT-d. Cr supplementation in GAMT-d treatment should include diet restrictions aimed at reducing GAA concentration in body fluids. (1)H- and especially (31)P-MR spectroscopy are the ideal tools for monitoring the therapy response to these disorders.     

The influence of laminin-derived peptides conjugated to Lys-capped PLLA on neonatal mouse cerebellum C17.2 stem cells

Chemical guiding cues are being exploited to stimulate neuron adhesion and neurite outgrowth. In this study, an amino-functioned PLLA, lysine-capped PLLA [K-(CH₂)_n-PLLA (n = 2, 5, 8)], was synthesized with different length of linking spaces between lysine molecule and PLLA backbone. Drop-cast films were fabricated from K-(CH₂)_n-PLLA/PLLA blends (10/90, w/w) and amino groups were detected on the surfaces of the resultant films. More amine groups were detected on the surface and the hydrophilicity of the films was obviously improved by annealing the films in water. The representative atomic force microscopy (AFM) images indicated that incorporation of lysine-capped PLLA into PLLA matrix increased the roughness of the films and resulted in a phase separation with distinct two nano-domains which may correspond to the hydrophilic and hydrophobic domains. Furthermore, the laminin-derived peptides, CYIGSR (Cys-Tyr-Ile-Gly-Ser-Arg) and CSIKVAV (Cys-Ser-Ile-Lys-Val-Ala-Val), were jointly tethered to the amine groups of lysine-capped PLLA by a linking reagent sulfo-succinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (Sulfo-SMCC). The neonatal mouse cerebellum C17.2 stem cells were seeded on the peptides-grafted K-(CH₂)_n-PLLA/PLLA (n = 2, 5, 8) films and pure PLLA films were used as controls. Improved viability and longer neurites were obtained on the peptide-grafted films than PLLA film over the cultivation period, especially for K-(CH₂)₅-PLLA/PLLA, which had the highest peptide density of 0.28 ± 0.03 μg/cm². This study highlights the potential of using the lysine-cappeded PLLA with laminin-derived peptides for promoting nerve regeneration.     

Tubular nanofiber scaffolds for tissue engineered small-diameter vascular grafts

Quick establishment of a confluent and stable endothelial cells (ECs) layer in the lumen of vascular grafts is critical for long-term patency of small-diameter vascular grafts. The objective of the study was to fabricate tubular nanofiber scaffolds, incorporate ECs onto the lumen of the scaffolds, and establish an animal model to prove the basic concept of using the scaffolds as vascular grafts. Poly(L-lactic acid)-co-poly(epsilon-caprolactone) P(LLA-CL 70:30) tubular nanofiber scaffolds were fabricated by electrospinning onto a rotating mandrel. Collagen was coated onto the scaffolds after air plasma treatment. Structure and mechanical property of the scaffolds were studied by scanning electron microscopy and tensile stress measurement, respectively. Human coronary artery endothelial cells (HCAECs) were rotationally seeded onto the lumen of the scaffolds at the speed of 6 rpm for 4 h through a customized seeding device, followed with static culture. Results showed evenly distributed and well-spread HCAECs throughout the lumen of the scaffold from 1 day onward to 10 days after seeding. Further, HCAECs maintained phenotypic expression of PECAM-1. To prove the basic concept of using the scaffolds as vascular grafts, acellular tubular P(LLA-CL) nanofiber scaffolds (inner diameter 1 mm) were implanted into rabbits to replace the inferior superficial epigastric veins. Results showed the scaffolds sustained the surgical process, kept the structure integrity, and showed the patency for 7 weeks.     

A small-molecule IAP inhibitor overcomes resistance to cytotoxic therapies in malignant gliomas in vitro and in vivo

We tested the use of the small-molecule Inhibitor of Apoptosis Protein (IAP) inhibitor LBW242 in combination with the standard-of-care therapies of irradiation and temozolomide for malignant gliomas. In vitro assays demonstrated that LBW242 enhanced the cytotoxic activity of radiotherapy, and clonogenic assays showed that the combination therapy led to a synergistic anti-glioma effect in multiple cell lines. Neurosphere assays revealed that the combination of radiation and LBW242 led to a pro-apoptotic effect in these glioma-initiating cell-enriched assays, with a corresponding inhibition of primary tumor cell growth. Athymic mice bearing established human malignant glioma tumor xenografts treated with LBW242 plus radiation and temozolomide demonstrated a synergistic suppression of tumor growth. Taken together, these experiments show that the pro-apoptotic and anti-glioma effects of radiotherapy and chemotherapy can be enhanced by the addition of a small-molecule IAP inhibitor. These results are readily translatable to clinical trial and offer the potential for improved treatment outcomes for patients with glioma.     

Sensitive and rapid titrimetric and spectrophotometric methods for the determination of stavudine in pharmaceuticals using bromate-bromide and three dyes

Four sensitive and rapid methods for the determination of stavudine (STV) in bulk drug and in dosage forms were developed and optimized. In titrimetry, aqueous solution of STV was treated with a known excess of bromate-bromide in HCl medium followed by estimation of unreacted bromine by iodometric back titration. Spectrophotometric methods involve the addition of a measured excess of bromate-bromide in HCl medium and subsequent estimation of the residual bromine by reacting with a fixed amount of methyl orange, indigocarmine or thymol blue followed by measurement of absorbance at 520 nm (method A), 610 nm (method B) or 550 nm (method C). In all the methods, the amount of bromate reacted corresponds to the amount of STV. Calculations in titrimetry were based on a 1:0.666 (STV:KBrO3) stoichiometry and the method was found to be applicable over 3.5-10 mg range. A linear increase in absorbance with concentration of STV was observed in the spectrophotometric methods, and the Beer's law was obeyed over the concentration ranges 0.125-1.75, 1-10 and 1-9.0 microg mL-1 STV for method A, method B and method C, respectively. The methods when applied to the determination of STV in tablets and capsules were found to give satisfactory results.     

The Transseptal T‐Cut—What More Can We See?

Abstract   An optimal approach to the mitral valve for repair or replacement must provide adequate exposure even in a small left atrial and redo cases, without need for forceful retraction. This benefit of good exposure must not be at the cost of increased morbidity from increased postoperative bleeding, SA node, or atrioventricular node dysfunction. We describe a simple technique of transseptal T-cut for exposure of the mitral valve, which is without the attendant complications of the other techniques.     

The mendosal suture of the occipital bone: occurrence in Indian population,embryology and clinical significance

The Occipital occipital bone is ontogenetically and functionally unique when compared to the other bones of the skull in humans and other mammalian cousins. The Occipital occipital bone develops from six ossification centers; any defect in the ossification process will give rise to mendosal suture (accessory suture) and conditions like posterior plagiocephaly. There is a paucity of literature regarding the mendosal suture and further more, its report in Indian population is not known. The present study was conducted to find out the occurrence of mendosal suture in the Indian dry skulls. Fifteen specimens (3%) were found to have these sutures out of five hundred500 skulls examined. Nine (3.1%) samples are of male skulls out of two hundred ninety (290) and six (2.85%) samples are that of female skulls out of two hundred ten210. The mendosal suture ran close to the superior nuchal line in all specimens and traveled medially from the lambdoidal suture. The length of the sutures ranged from 0.8 cm to 2.6 cm (1.88 cm) on the right side and 1.4 cm to 2.9 cm (1.94 cm) on the left side respectively in male skulls; and 0.7 cm to 2.8 cm (1.55 cm) on the right side and 1 cm to 2.4 cm (1.42 cm) on the left side, respectively, in female skulls. The origin of mendosal suture from the lambdoidal suture was 5.7 cm to –6.3 cm (5.98 cm) from the tip of the mastoid process on the right side and 5.6 to –6.3 cm (6 cm) on the left side, respectively, in male skulls; and 5.4 cm to –5.8 cm (5.58 cm) on the right side and 5.4 cm to –5.6 cm on the left side respectively in female skulls. The occurrence and clinical significance of the present study is discussed.