Relation between structural and release properties in a polysaccharide gel system

The potential utility of kappa-carrageenan gels for preparing drug release devices is here shown. Structural properties of kappa-carrageenan gels prepared with different salt composition and containing Ketoprofen sodium salt, as model drug, have been evaluated with static light scattering and rheological measurements. These properties have been correlated with release profiles in vitro at pH 5.5. Release properties from gelled matrices have been compared with those obtained by two commercial products containing the same drug. Results show that: i) in this system it is possible to easily control the gel texture by using different cationic concentration; ii) the kinetics of drug release by kappa-carrageenan gels are dependent on the structural properties of matrices; iii) in the typical interval time used in classical local applications, all gel samples release the loaded drug almost completely, at difference with the commercial products. All these findings can provide useful suggestions for the realization of classical topical release systems.

Adrenal pheochromocytoma and jejunal neurofibroma in type 1 neurofibromatosis: report of a case

INTRODUCTION

Neurofibromatosis type 1 (NF1), known as von Recklinghausen's disease, is characterized by presence of café au lait spots, and neurofibromas in the skin or along the course of peripheral nerves. Diagnosis, despite extreme clinical variability, is defined by established diagnostic criteria. Clinical status is frequently complicated by systemic disorders and neoplasias.

CASE REPORT

A case of a patient affected by NF1, with hypertension due to adrenal pheochromocytoma and with jejunal neurofibroma, is reported.

DISCUSSION AND CONCLUSIONS

Variability in clinical presentation of NF1 with possible manifestation of severe systemic benign and malignant diseases requires strict follow-up and specific screening of extra-cutaneous lesions.

[Peri-inguinal strangulated hernia: report of a case]

Peri-inguinal hernias are rare defects of ventral lateral abdominal wall, just above the inguinal region. These hernias are due to congenital defects of internal oblique and transverse muscles. Since their rarity and the complex anatomy of the region, their correct classification is still debated. It is possible to make diagnosis by clinical examination; imaging can help the physician to recognize this rare pathology. The Authors describe a case of strangulated peri-inguinal hernia, that required urgent surgery.

A new biodegradable and biocompatible hydrogel with polyaminoacid structure

The preparation and physicochemical and biological characterization of a novel polyaminoacid hydrogel have been reported. The alpha,beta-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) has been used as a starting polymer for a derivatization reaction with methacrylic anhydride (MA) to give rise to the methacrylate derivative named PHM. Photocrosslinking of PHM has been performed in aqueous solution at 313 nm and in the absence of toxic initiators. PHM-based hydrogel has been characterized by scanning electron microscopy, X-ray diffractometry, swelling measurements in aqueous media; the degradation of PHM-based hydrogel has been evaluated as a function of time in the absence or in the presence of esterase. Besides, the biocompatibility of this hydrogel and of its degradation products has been evaluated by performing in vitro assays on human chronic myelogenous leukaemia cells (K-562), chosen as a model cell line. Finally, ATR-FTIR measurements have showed that interaction between PHM-based hydrogel and each of four plasma proteins (albumin, gamma-globulin, transferrin and fibrinogen) does not cause change in protein conformation thus supporting its potential use as a material to prepare parenteral drug delivery systems.

The functions of Sco proteins from genome-based analysis

Sco proteins are widespread proteins found in eukaryotic as well as in many prokaryotic organisms. The 3D structure of representatives from human, yeast, and Bacillus subtilis has been determined, showing a thioredoxin-like fold. Sco proteins have been implicated mainly as copper transporters involved in the assembly of the CuA cofactor in cytochrome c oxidase. Some mutations have been identified in humans that lead to defective cytochrome c oxidase formation and thus to fatal illnesses. However, it appears that the physiological function of Sco proteins goes beyond assembly of the CuA cofactor. Extensive analysis of completely sequenced prokaryotic genomes reveals that 18% of them contain either Sco proteins but not CuA-containing proteins or vice versa. In addition, in several cases, multiple Sco-encoding genes occur even if only a single potential Sco target is encoded in the genome. Genomic context analysis indeed points to a more general role for Sco proteins in copper transport, also to copper enzymes lacking a CuA cofactor. To obtain further insight into the possible role of Sco in the assembly of other cofactors, a search for Cox11 proteins, which are important for CuB biosynthesis, was also performed. A general framework for the action of Sco proteins is proposed, based on the hypothesis that they can couple metal transport and thiol/disulfide-based oxidoreductase activity, as well as select between either of these two cellular functions. This model reconciles the variety of experimental observations made on these proteins over the years, and can constitute a basis for further studies.

Primary lumbar hernia repair: the open approach

BACKGROUND

Lumbar hernias arise through posterolateral abdominal wall defects, named inferior triangle (Petit) and superior triangle (Grynfelt). Most of the lumbar hernias are secondary to trauma or previous surgery, while primary lumbar hernias are rare. There are two possible surgical approaches: the anterior approach with lumbar incision and the laparoscopic (transabdominal or totally extraperitoneal) approach.

METHODS

We present a series of nine surgical procedures for primary lumbar hernia in 7 adult patients (2 affected by bilateral hernias). Seven were Grynfelt hernias, and two were Petit hernias. All surgical repairs were performed using synthetic mesh placed in the extraperitoneal space, below the muscular layers, using a tension-free technique.

RESULTS

There was no surgical complication, except for 1 case with a subcutaneous haematoma. The mean hospital stay was 2.3 days. All patients returned to normal daily activities within 15 days after surgery. After a median follow-up period of 25 months, there was no case of recurrence or postsurgical sequelae, such as pain or muscular weakness.

CONCLUSIONS

Primary lumbar hernias are rare congenital defects of the abdominal wall. Repair of these rare hernias can be successfully performed via the anterior approach with the use of synthetic mesh - this method of repair is easy, safe, and effective.

Giant GIST of the mesocolon: report of a case

Gastrointestinal stromal tumors are rare neoplasms arising from mesenchymal cells of the gastrointestinal tract, that strongly express a class III receptor tyrosine kinase, called KIT, due to some mutations in the KIT proto-oncogene. Two thirds of GISTs are found in the stomach, 20% to 50% in the small bowel (one third in the duodenum), and 5% to 15% in colon and rectum; GISTs, however, may rarely be found also in the oesophagus, omentum, mesentery or the retroperitoneum. Their treatment is strictly surgical, and only R0 resection can achieve good

RESULTS

Treatment with Imatinib seems to be promising in case of unresectable or metastatic GIST, even if some trials are studying its effects after curative resection. GIST of the mesocolon are rare, and as in the other locations, require extensive surgery. The Autohrs report a case of giant malignant GIST arising from transverse mesocolon, treated by en-bloc resection of the tumor with a segment of transverse colon and great omentum.

Structural basis for the observed differential magnetic anisotropic tensorial values in calcium binding proteins

Lanthanide ions (Ln(3+)), which have ionic radii similar to those of Ca(2+), can displace the latter in a calcium binding protein, without affecting its tertiary structure. The paramagnetic Ln(3+) possesses large anisotropic magnetic susceptibilities and produce pseudocontact shifts (PCSs), which have r(-3) dependence. The PCS can be seen for spins as far as 45 A from the paramagnetic ion. They aid in structure refinement of proteins by providing long-range distance constraints. Besides, they can be used to determine the interdomain orientation in multidomain proteins. This is particularly important in the context of a calcium binding protein from Entamoeba histolytica (EhCaBP), which consists of two globular domains connected by a flexible linker region containing 8 residues. As a first step to obtain the interdomain orientation in EhCaBP, a suite of 2D and 3D heteronuclear experiments were recorded on EhCaBP by displacing calcium with Ce(3+), Ho(3+), Er(3+), Tm(3+), Dy(3+), and Yb(3+) ions in separate experiments, and the PCS of (1)H(N) and (15)N spins were measured. Such data have been used in the refinement of the individual domain structures of the protein in parallel with the calculation of the respective magnetic anisotropy tensorial values, which differ substantially (2.1-2.8 times) from what is found in other Ca(2+) binding loops. This study provides a structural basis for such variations in the magnetic anisotropy tensorial values.

[A case of primitive amyloid goiter]

Amyloid goiter is a rare pathology due to massive amyloid infiltration of thyroid tissue, which cause diffuse or localized enlargement of the gland. It can be totally asymptomatic or cause only non-specific symptoms (compression of adjacent structures, tracheal deviation). Thyroid disfunction (hypothyroidism or hyperthyroidism) is rare. It is important to differentiate primitive amyloid goiter from other kinds of amyloid infiltration of the thyroid, such as in systemic amyloidosis. The correct diagnosis can be difficult because of the common presence of amyloid in thyroid neoplasms, such as medullary thyroid carcinoma (MTC). The Authors present a case of primitive amyloid goiter, that needed immunohistochemical analysis for a correct diagnosis, and a review of the concerning literature.

Predicting metals sensed by ArsR-SmtB repressors: allosteric interference by a non-effector metal

Many bacterial genomes encode multiple metal-sensing ArsR-SmtB transcriptional repressors. There is interest in understanding and predicting their metal specificities. Here we analyse two arsR-smtB genes, ydeT and yozA (now aseR and czrA) from Bacillus subtilis. Purified AseR and CzrA formed complexes in gel-retardation and fluorescence-anisotropy assays with fragments of promoters that were derepressed in DeltaaseR and DeltaczrA cells. Candidate (i) partly thiolate, alpha3-helix (for AseR) and (ii) tetrahedral, non-thiolate, alpha5-helix (for CzrA) metal binding sites were predicted then tested in vitro and/or in vivo. The precedents are for such sites to sense arsenite/antimonite (alpha3) and zinc (alpha5). This correlated with the respective metal inducers of AseR and CzrA repressed promoters in B. subtilis and matched the metals that impaired formation of protein-DNA complexes in vitro. The putative sensory sites of 1024 ArsR-SmtB homologues are reported. Although AseR did not sense zinc in vivo, it bound zinc in vitro exploiting alpha3 thiols, but AseR DNA binding was not impaired by zinc. If selectivity relies on discriminatory triggering of allostery not just selective metal binding, then tight non-effector metal complexes could theoretically inhibit metal sensing. AseR remained arsenite-sensitive in equimolar zinc, while CzrA remained zinc-sensitive in equimolar arsenite in vitro. However, cupric ions did not impair CzrA-DNA complex formation but did inhibit zinc-mediated allostery in vitro and prevent zinc binding. Access to copper must be controlled in vivo to avoid formation of cupric CzrA.

Dual role of VEGF in pretreated experimental ePTFE arterial grafts

BACKGROUND

Lack of endothelialization and abnormal smooth muscle cell (SMC) growth adversely affect the outcome of vascular synthetic grafts. The aims of our study were to investigate how a coating of extracellular matrix (ECM) and vascular endothelial growth factor (VEGF) might affect the endothelialization rate, smooth muscle cells (SMC) proliferation, and myointimal hyperplasia in experimental arterial ePTFE grafts.

METHODS

In each of 30 male Lewis rats, a 1-cm-long ePTFE graft was inserted at the level of the abdominal aorta. Animals were randomized in five groups (six animals each): groups A and A1 received ePTFE grafts coated with a synthetic extracellular matrix (growth factor-reduced matrigel) containing VEGF; groups B and B1 received ePTFE grafts coated with synthetic ECM; and group C received ePTFE grafts alone. The grafts were explanted at 30 days from surgery for immunohistochemical analysis.

RESULTS

Both endothelialization rate and myointimal hyperplasia were augmented in group A versus groups B and C, and these findings were statistically significant. SMC density resulted significantly higher in group A versus groups B and C, and this was associated with an altered expression of bFGF and TGFbeta.

CONCLUSIONS

Pretreating ePTFE grafts with synthetic ECM and VEGF results in better endothelialization, but also in undesired higher SMC density and myointimal hyperplasia.

A structural model for the adduct between cytochrome c and cytochrome c oxidase

An ensemble of structural models of the adduct between cytochrome c and cytochrome c oxidase from Paracoccus denitrificans has been calculated based on the experimental data from site-directed mutagenesis and NMR experiments that have accumulated over the last years of research on this system. The residues from each protein that are at the protein-protein interface have been identified by the above experimental work, and this information has been converted in a series of restraints explicitly used in calculations. It is found that a single static structural model cannot satisfy all experimental data simultaneously. Therefore, it is proposed that the adduct exists as a dynamic ensemble of different orientations in equilibrium, and may be represented by a combination or average of the various limiting conformations calculated here. The equilibrium involves both conformations that are competent for electron transfer and conformations that are not. Long-range recognition of the partners is driven by non-specific electrostatic interactions, while at shorter distances hydrophobic contacts tune the reciprocal orientation. Electron transfer from cytochrome bc (1) to cytochrome c oxidase is mediated through cytochrome c experiencing multiple encounters with both of its partners, only part of which are productive. The number of encounters, and thus the electron transfer rate, may be increased by the formation of a cytochrome bc (1)-cytochrome c oxidase supercomplex and/or (in human) by increasing the concentration of the two enzymes in the membrane space.

K+ and Na+ effects on the gelation properties of κ-Carrageenan

The effects of K(+), Na(+) ions and their mixture on the conformational transition and macroscopic gel properties of kappa-Carrageenan system have been studied using different experimental techniques. The macroscopic gelation properties of kappa-Carrageenan were found to be dependent upon cosolute type. Indeed, a more ordered and strong gel was obtained in the presence of K(+) with respect to Na(+) ions. The gel properties obtained using mixtures of two cosolutes are shown to depend on the [K(+)]/[Na(+)] ratio.

Synthesis, physico-chemical and biological characterization of a paclitaxel macromolecular prodrug

Paclitaxel was attached to poly(hydroxyethylaspartamide) via a succinic spacer arm by a two-step protocol: (1) synthesis of 2'-O-succinyl-paclitaxel; (2) synthesis of PHEA-2'-O-succinyl-paclitaxel. The 2'-O-succinyl-paclitaxel derivative and the macromolecular conjugate were characterized by UV, IR, NMR and mass spectrometry analysis. The reaction yields were over 95% and the purity of products over 98%. Paclitaxel release and degradation from 2'-O-succinyl-paclitaxel occurred at a faster rate at pH 5.5 than 7.4. After 30 h of incubation at pH 5.5 and 7.4 the released free paclitaxel was about 40 and 20%, respectively. In plasma both drug release and degradation were found to occur at a higher rate than in buffer at pH 7.4 suggesting that an enzymatic mechanism could be involved. The paclitaxel release and degradation from PHEA-2'-O-succinyl-paclitaxel were negligible at pH 5.5 and 7.4 and very slow in plasma. Investigation carried out using murine myeloid cell line showed that the polymeric prodrug maintains partial pharmacological activity of paclitaxel. The DL50 of the conjugate (over 40 ng/ml) as compared to free paclitaxel (about 1 ng/ml) was correlated to the slow drug release. Finally a pharmacokinetic study carried out by intravenous inoculation of the macromolecular prodrug to mice demonstrated that the polymer conjugation modify dramatically the in vivo fate of the drug. The conjugate disappeared from the bloodstream much more quickly as compared to both free drug and naked polymer. Massive accumulation of bioconjugate in the liver (80% of the dose) was found to persist throughout 1 week.

Paramagnetism-based restraints for Xplor-NIH

Modules that use paramagnetism-based NMR restraints have been developed and integrated in the well known program for solution structure determination Xplor-NIH; the complete set of such modules is called PARArestraints for Xplor-NIH. Paramagnetism-based restraints are paramagnetic relaxation enhancements, pseudocontact shifts, residual dipolar couplings due to metal and overall magnetic anisotropy, and cross correlation between Curie relaxation and nuclear-nuclear dipolar relaxation. The complete program has been tested by back-calculating NOEs and paramagnetism-based restraints from the X-ray structure of cytochrome c (553) from B. pasteurii. Furthermore, the same experimental restraints previously used to determine the solution structure of cytochrome c (553) itself, of cytochrome b (5), and of calbindin D(9k) with the program PARAMAGNETIC DYANA, have been used for structure calculations by using PARArestraints for Xplor-NIH. The agreement between the two programs is quite satisfactory and validates both protocols.

[Endometriosis of the abdominal wall (authors' experience)]

Endometriosis is a very common gynecological disease, although the abdominal wall localization is a rare clinical problem in the everyday practice and this explains the incomplete reports in literature and the difficulty of a standard treatment. The authors report four cases of abdominal wall endometriosis, underlining how the surgical therapy represents the golden standard of decisive treatment, thanks also to prosthetic reconstruction techniques who allow more radical demolitions. On the contrary, the medical treatment should be reserved to selected cases such as especially the less symptomatic umbilical primitive diseases.

Presurgical antimicrobial prophylaxis: effect on ocular flora in healthy patients

OBJECTIVE

Evaluation of presurgical antimicrobial prophylaxis for reduction of ocular flora.

SETTING

Ophthalmology Section, Department of Medicine and Surgery, University of Catania, Italy.

METHODS

Three days before photorefractive keratectomy (PRK), conjunctiva of 70 healthy patients (100 eyes) were swabbed. After 3 days of instillation of ofloxacin 0.3% (3 times daily), conjunctival swabs were taken again. Bacteria were isolated and identified from each swab.

RESULTS

A total of 191 independent isolates were obtained prior to antimicrobial treatment. Bacteria were isolated from all 100 eyes sampled. Gram-positive species predominated, with Staphylococcus epidermidis and Staphylococcus aureus cultured from 69% and 25% of eyes sampled, respectively. Species of the anaerobic genera Peptococcus and Peptostreptococcus were found in 22% and 14% of eyes, respectively. After prophylaxis with ofloxacin, bacteria could be cultured from only 7% of eyes (10 independent isolates). All isolates were sensitive to ofloxacin except 5 strains of S. epidermidis, which displayed intermediate sensitivity. No infections occurred after PRK.

CONCLUSION

Prophylaxis by instillation of ofloxacin 0.3% 3 times daily for 3 days substantially reduced the ocular flora of 100 healthy eyes prior to refractive surgery.

Plug-technique for small incisional hernia

OBJECTIVE

The authors report their experience with a new prosthetic technique for the repair of incisional hernia defects smaller than 3 cm.

METHODS

From January 1995 to September 2002, 16 operations for small incisional hernias have been performed. Local anaesthesia was used in 12 out of 16 patients (75%). The repair was achieved by insertion of a polypropylene plug sutured to the margins of the hernial defect.

RESULTS

All patients were discharged within 24 hours of surgery. Postoperative pain was mild and required hospital analgesia in 25% of cases. Back at home analgesia was needed in only 1 patient. During a follow-up ranging 3 to 91 months (mean 46), no recurrence has been recorded.

CONCLUSION

The proposed technique allows a sound repair of small incisional hernias with minimal pain, quick rehabilitation and early return to unrestricted work.

A use of Ramachandran potentials in protein solution structure determinations

A strategy is developed to use database-derived phi-psi constraints during simulated annealing procedures for protein solution structure determination in order to improve the Ramachandran plot statistics, while maintaining the agreement with the experimental constraints as the sole criterion for the selection of the family. The procedure, fully automated, consists of two consecutive simulated annealing runs. In the first run, the database-derived phi-psi constraints are enforced for all amino acids (but prolines and glycines). A family of structures is then selected on the ground of the lowest violations of the experimental constraints only, and the phi-psi values for each residue are examined. In the second and final run, the database-derived phi-psi constraints are enforced only for those residues which in the first run have ended in one and the same favored phi-psi region. For residues which are either spread over different favored regions or concentrated in disallowed regions, the constraints are not enforced. The final family is then selected, after the second run, again only based on the agreement with the experimental constraints. This automated approach was implemented in DYANA and was tested on as many as 12 proteins, including some containing paramagnetic metals, whose structures had been previously solved in our laboratory. The quality of the structures, and of Ramachandran plot statistics in particular, was notably improved while preserving the agreement with the experimental constraints.

[Bilateral breast cancer]

Bilateral breast cancer has a cumulative incidence of 3-13% in patients with primary breast cancer, and the majority of these lesions are metachronous. The synchronous and metachronous bilateral breast cancer have at greater risk for distant metastasis than unilateral breast cancer. There was no difference in overall survival when comparing metachronous and synchronous bilateral patients to those with unilateral disease.