Preparation of ABCBA-type block copolymers by use of macro-initiators containing peroxy and azo groups

Some new macroinitiators ( 5 ) containing azo and peroxy groups were synthesized by transformation of esters of poly(ethylene glycol) ( 1 ) (PEG) of different molecular weight with hydroxyl end groups and an azo group in the middle into the corresponding polymers with tert-butylperoxycarbonyl end groups by reaction with terephthaloyl chloride and subsequently with tert-butyl hydroporoxide. Decomposition in the presence of styrene at 60°C or with 3,6,9-triazaun-decane-1,11-diamine in presence of methyl methacrylate gave the corresponding ABA block copolymer 6 and the ABBA block copolymer 7 , respectively. Both block copolymers were used as polymeric initiators. The ABCBA block copolymer 8 was synthesized from 6 and methyl methacrylate or from 7 and styrene by thermally induced polymerization at 80°C. The resulting block copolymers were separated from the homopolymers by selective solvent extraction and characterized by spectroscopic and fractional precipitation methods.     

Bone marrow transplantation from matched siblings in patients with fanconi anemia utilizing low-dose cyclophosphamide, thoracoabdominal radiation and antithymocyte globulin

Nineteen patients with Fanconi anemia (FA) and bone marrow failure underwent bone marrow transplantation (BMT) from matched siblings. Median age at BMT was 8.7 years. Conditioning consisted of low-dose cyclophosphamide (CY 5 mg/kg x 4 days) and thoracoabdominal irradiation (TAI 400 cGy). Graft-versus-host disease (GVHD) prophylaxis was cyclosporin A (CsA) in 13 patients and CsA plus methotrexate in 6 patients. Antithymocyte globulin (ATG) was added in the pretransplant as well as the post-transplant period. All patients received high-dose acyclovir from day 2 pre-BMT to day 28 post BMT, and intravenous immunoglobulins (IVIG), 500 mg/kg weekly from day 7 pre-BMT to day 90 post BMT. No fungal prophylaxis was given. All patients engrafted, (median, 14 days for an absolute neutrophil count > or =0.5 x 10(9)/l; median, 37 days for platelet count > or =20 x 10(9)/l). Fourteen (74%) patients are alive with sustained engraftment and are transfusion independent. Three (16.6%) patients developed acute GVHD; none developed chronic GVHD. Five (26%) patients developed invasive fungal infections, and two (10%) developed fatal CMV disease. We believe the addition of ATG may have contributed to the increased incidence of severe life-threatening fungal and viral infections in our series.     

Effects of 10?days of modest intermittent hypoxia on circulating measures of inflammation in healthy humans

Purpose

Obstructive sleep apnea (OSA) is a common disease which is associated with elevated inflammatory markers and adhesion molecules, possibly due to nightly intermittent hypoxia (IH). The purpose of this study was to test the hypothesis that IH would increase systemic inflammatory markers in healthy human males.

Methods

Healthy, young male subjects (n?=?9; 24?±?2?years) were exposed to a single daily isocapnic hypoxia exposure (oxyhemoglobin saturation?=?80%, 1?h/day) for 10 consecutive days. Serum granulocyte macrophage colony-stimulating factor, interferon-??, interleukin-1??, interleukin-6, interleukin-8, leptin, monocyte chemotactic protein-1, vascular endothelial growth factor, intracellular adhesion molecule-1, and vascular cell adhesion molecule-1 were measured before and following the 10?days of IH using Luminex.

Results

Nine subjects completed the study (24?±?2?years; 24?±?2?kg/m²). The mean oxyhemoglobin saturation was 80.8?±?1.6% during the hypoxia exposures. There was no significant change in any of the markers of inflammation (paired t test, P?>?0.2 all cytokines).

Conclusions

These findings suggest that (1) a more substantial or a different pattern of hypoxemia might be necessary to activate systemic inflammation, (2) the system may need to be primed before hypoxic exposure, or (3) increases in inflammatory markers in patients with OSA may be more related to other factors such as obesity or nocturnal arousal.     

Levels of gingival tissue platelet activating factor after conventional and regenerative periodontal surgery

The hypothesis, a relationship between gingival tissue platelet activating factor (PAF) levels and healing after periodontal surgery, was tested by measuring PAF levels in gingival tissues collected from sites that had undergone flap surgery and guided tissue regeneration (GTR) or flap surgery alone. Using a split-mouth design, 20 intrabony defects were randomly assigned to treatment with flap surgery and GTR (group 1) or with flap surgery alone (group 2). Gingival tissue samples were obtained at surgery (baseline) and at 6-month follow-up evaluation visit. One half of each sample was used for analysis of PAF levels by high-performance liquid chromatography, and the other half of the sample was used for histomorphometric analysis that included measurements of number and diameter of blood vessels. PAF levels and diameter of blood vessels were significantly decreased (p < 0.01), and the number of blood vessels was significantly increased (p < 0.05) in both groups after 6 months compared to the baseline values. Postoperative number of blood vessels were significantly higher in group 1 (p < 0.05), whereas there was no significant difference in postoperative PAF levels between the two groups (p > 0.05). Based on the reported results, it is suggested that a decrease in gingival PAF levels might be found after conventional and regenerative periodontal surgery.     

Comparison of the proliferative activity in gingival epithelium after surgical treatments of intrabony defects with bioactive glass and bioabsorbable membrane

Guided tissue regeneration is based on preventing the more rapidly proliferating epithelium from growing into the periodontal defect after surgical procedures incorporating barrier membranes. The aim of this study was to compare the proliferative activity of gingival epithelium using proliferating cell nuclear antigen (PCNA) as a marker of cell proliferation after surgical treatments with bioactive glass graft material and bioabsorbable membrane. Using split mouth design, 20 intrabony defects were randomly assigned treatments with bioactive glass (BG group) or bioabsorbable membrane (BM group). Gingival biopsies were taken at preoperative and postoperative 12 weeks. After histological processing, the number of the inflammatory cells was measured in hematoxylin and eosin-stained sections; PCNA expression was determined in immunohistochemically-stained sections. At postoperative 12 weeks, the number of the inflammatory cells was significantly decreased (p < 0.01), PCNA expression was significantly increased (p < 0.001) in both treatment groups compared to baseline data. There was no significant difference in PCNA expression between baseline values of two groups (p > 0.05), while at postoperative 12 weeks, increase in BG group was significantly greater than that in BM group (p < 0.001). These results suggest that epithelial cell proliferation is more prominent after treatment of intrabony defects with bioactive glass compared to the treatment with bioabsorbable membrane.     

Stem cell transplantation for patients with Fanconi anemia with low-dose cyclophosphamide and antithymocyte globulins without the use of radiation therapy

In all, 22 patients with confirmed Fanconi anemia (FA) underwent stem cell transplantation (SCT) from HLA-matched, related donors at KFSHRC. Median age at SCT was 7.6 years (range, 2.5-14.6 years). Conditioning regimen consisted of cyclophosphamide (CY) 15 mg/kg/day intravenously (i.v.) for 4 consecutive days, in addition to equine antithymocyte globulins (ATG) given i.v. at 40 mg/kg/day for four doses pre-SCT. No radiation therapy was given. For graft-versus-host disease prophylaxis, we used cyclosporin at the standard doses; ATG was added at 20 mg/kg/dose i.v. on days 2, 4, 6, 8, 10, and 12 post-SCT (total of six doses). All patients engrafted and are alive and transfusion independent with a median follow-up time of 20.2 months (range, 3.3-59 months). One patient however developed a decrease in her WBC and platelet count. Her work-up revealed slightly hypocellular bone marrow, and a series of chimerism studies over 1 year confirmed that she has stable mixed chimerism; she remains transfusion independent. We conclude that low-dose CY without radiation therapy can be used satisfactorily in the conditioning of patients with FA undergoing related SCT.     

Localised Ewing sarcoma/PNET of bone--prognostic factors and international data comparison

BACKGROUND: To determine if the distribution of prognostic factors accounted for the differences when the outcome for localised Ewing Sarcoma/PNET bone in Saudi Arabia was compared with results from countries with well developed health care systems. PROCEDURE: Retrospective analysis was undertaken of 163 consecutive patients of all ages, treated with radical intent at KFSHRC from 1975 to 1998. Standard chemotherapy was commenced in all patients. The local treatment modality was resection +/- radiation in 30% and radiation treatment alone in 67%. Size data were available for 51 patients treated from 1994 to 1998, inclusive. One third of these patients had tumors with volume >500 ml. RESULTS: Three year survival significantly increased with the year of diagnosis, 1975-1988 45%; 1989-1993 55%; and 1993-1998 63% (P = 0.006). Favorable prognostic factors were age < or =14 (P = 0.07); site, distal extremity, and skull (P = 0.08); and volume < or = 200 ml (P = 0.06). Secondary prognostic factors were response to induction chemotherapy, both histological, 100% necrosis, (P = 0.04) and clinical CR+PR, (P = 0.02). From 1994 to 1998, 3 year survival for tumors in the distal extremity and skull was 80% and for small tumors, < 200 ml, at any site was 82%. In comparison, the 3 year survival for patients with tumors at any other sites was 60%, and for tumors >200 ml, 55%. CONCLUSIONS: Overall survival progressively improved. From 1994 to 1998 the survival of patients with small tumors and/or favorable sites was similar to the best reported results. It was not possible to compare results by tumor size for large tumors, > 500 ml, due to the absence of data from elsewhere. A better staging system is required for the international comparison of results.     

The effects of irrigation fluid volume and irrigation time on fluid electrolyte balance and hemodynamics in percutaneous nephrolithotripsy

Objective: to determine fluid-electrolyte andhemodynamics changes and complicationsassociated with irrigation fluid volume andtime in percutaneous nephrolithotripsy in that0.9% NaCI was used as irrigant.Methods: Standard anaesthetic procedureswere performed to 6 women and 16 men. Meanarterial pressure, heart rate, central venouspressure, Na⁺, K⁺, osmolality,haemoglobin, haematocrit were recorded before,during and after irrigation every 10 minutes.Creatinine and blood urea nitrogen weredetermined before and after irrigation.Moreover, the operation and irrigation times,irrigation fluid volume, total fluid outputversus input, blood transfusions andcomplications were recorded.Results: Mean arterial pressure, heartrate, central venous pressure, Na⁺,K⁺, osmolality did not changesignificantly during and after irrigation andno relationship was observed between those withirrigation volume and time. Creatinine andblood urea nitrogen values during and afterirrigation did not change significantly versusthose before irrigation. Although no bloodtransfusion was needed for any case during theprocedure, it was necessary for two cases afterthe procedure. One case with pneumothorax thatdeveloped during procedure was treated byinserting a thoracic tube.Conclusion: There were no significantchanges in fluid-electrolyte balance andhemodynamics related to both irrigation fluidvolume and irrigation time when 0.9% NaCI wasused in PNL.