Modeling of Coulomb coupling and acoustic wave propagation in LiNbO3

The angular spectrum propagation technique is applied to modeling of wave propagation through piezoelectric media. The calculations of the angular spectrum propagator are based on the relevant equation for the slowness surface resulting from the solution of the Christoffel equation with piezoelectrically stiffened elastic constants. A two-dimensional FFT algorithm is applied in the final field superposition. We concentrate on the case of Coulomb coupling through local electrical point contacts on both the excitation and detection side. To model that case we superpose solutions for acoustic Green's functions of different propagation modes convoluted with equivalent distributed effective sources. Calculated results are in good agreement with the measured ones.

Arsenic trioxide inhibits ATRA-induced prostaglandin E2 and cyclooxygenase-1 in NB4 cells, a model of acute promyelocytic leukemia

In acute promyelocytic leukemia (APL), all-trans retinoic acid (ATRA) triggers cell differentiation, while arsenic trioxide (As(2)O(3)) generates partial differentiation and apoptosis. Animal and human studies suggest that newly diagnosed APL patients can be cured using As(2)O(3) combined with ATRA. Cyclooxygenases are involved in prostaglandins and thromboxane synthesis. We have recently demonstrated that ATRA induces cyclooxygenase-1 (COX-1) expression and prostaglandin synthesis in NB4 cells and in blasts from patients with APL. In the present study we investigated the effect of ATRA and As(2)O(3) co-treatment on COX-1 expression and prostaglandin formation and tested the effect of the COX-1/COX-2 nonselective inhibitor indomethacin on cell differentiation. Arsenic treatment of NB4 cells resulted in a partial but significant reduction of ATRA-dependent induction of COX-1 expression and activity. Pretreatment of NB4 cells with indomethacin significantly impaired ATRA/As(2)O(3)-induced differentiation, as assessed by cell morphology, nitroblue tetrazolium test or CD11c expression. PGE(2) reversed the negative effect of indomethacin on differentiation of ATRA/As(2)O(3)-treated NB4 cells. In conclusion, COX-1 contributes to ATRA-dependent maturation of NB4 cells and is affected by As(2)O(3). These results also suggest that nonsteroidal antiinflammatory drugs should be avoided in APL patients treated with the combination of ATRA and As(2)O(3).

Nod factor enhances calcium uptake by soybean

Inoculation with rhizobia or application of Nod factors (lipo-chitooligosaccharides, LCOs) causes transient increases in cytosolic calcium concentration in root hairs of legume plants. We conducted experiments to evaluate whether application of LCO and inoculation with rhizobia improved (45)CaCl(2) uptake into soybean (Glycine max [L.] Merr.) leaves. Roots of soybean seedlings with one developing trifoliolate were immersed in Murashige and Skoog (MS) basal liquid medium containing treatment solutions and (45)CaCl(2), and the plants were incubated under continuous light. After 24 h, leaf samples were taken, and their radioactivity levels were determined. Addition of NodBj-V (C18:1 MeFuc) at a concentration of 10(-7) M increased (45)Ca(2+) uptake. Inoculation with genistein-induced Bradyrhizobium japonicum strain 532C and USDA3 also increased (45)Ca(2+) uptake; whereas, inoculation with strain Bj-168, a nodC-mutant incapable of producing LCO, did not. Rhizobia that do not normally nodulate soybean, i.e. Rhizobium leguminosarum, and Sinorhizobium meliloti did not affect calcium uptake, nor did the tetramer or pentamer of chitosan, or lumichrome. Surprisingly, Rhizobium sp. NGR234, which can nodulate some types of soybean, although without effective N(2)-fixation, also did not affect calcium uptake. This work suggests that the rhizobial symbiosis, in addition to its known role in provision of nitrogen fixation, also improves early calcium uptake into soybean plants.

Cyclooxygenase-1, but not -2, is upregulated in NB4 leukemic cells and human primary promyelocytic blasts during differentiation

Cyclooxygenase (COX)-1 or -2 and specific prostaglandin (PG) synthases catalyze the formation of various PGs. We investigated the expression and activity of COX-1 and -2 during granulocyte-oriented maturation induced by all-trans-retinoic acid (ATRA) of NB4 cells, originated from a human acute promyelocytic leukemia (APL), and in blasts from APL patients. The expression of COX isoenzymes or prostaglandin synthases was also investigated in circulating granulocytes and human bone marrow. COX-1 was expressed and enzymatically active in NB4 cells and primary blasts. COX-1 mRNA and protein were induced by ATRA. COX-1 protein increased approximately 2-3.5-fold by culture day 3 in NB4 cells and primary blasts, while basal COX-2 expression was very low and unaffected by ATRA. COX-1-dependent PGE(2) biosynthesis increased during differentiation approx. 5-fold. Indomethacin and the selective COX-1 inhibitor SC-560, but not selective COX-2 inhibition, impaired NB4 differentiation, reducing NADPH-oxidase activity, CD11b and CD11c expression. The immunohistochemistry of granulocytes and myeloid precursors in the bone marrow showed a large prevalence of COX-1 as compared to COX-2. In conclusion, COX-1 is induced during ATRA-dependent maturation and appears to contribute to myeloid differentiation both in vitro and ex vivo, and COX-1 activity may potentiate the differentiation of human APL.Leukemia (2004) 18, 1373-1379. doi:10.1038/sj.leu.2403407 Published online 10 June 2004

Clinical characteristics and outcomes of diabetic ketoacidosis in Pakistani adults with Type 2 diabetes mellitus

AIMS

The aim of this study was to describe the clinical characteristics and outcomes of diabetic ketoacidosis (DKA) in Pakistani adult population with Type 2 diabetes mellitus.

METHODS

We reviewed the medical records of all adult patients admitted with a diagnosis of DKA and Type 2 diabetes mellitus (DM) and followed their clinical course and outcome. Follow-up data were obtained by chart review or telephone contact where necessary.

RESULTS

Fifty-seven patients fulfilled criteria for inclusion in the study. Their mean age was 48 +/- 7 years. The mean body mass index was 25.5 +/- 6.2 kg/m2. Forty-nine had a prior history of Type 2 DM but DKA was the initial presentation in 14%. Nine were on no treatment, 40 were using oral hypoglycaemic agents and eight were on insulin. A history of prior DKA was noted in eight patients. Infections were the most common precipitating factor (63%). There were 12 deaths. Follow-up after a period ranging between 12 and 43 months revealed that 30/45 patients remained on OHA without recurrence of DKA.

CONCLUSION

This report highlights the need for the growing recognition of DKA occurring in adults with Type 2 DM in the South Asian population. Mortality rates are unacceptably high but the majority of survivors remain insulin independent.

Thrombin induces angiogenesis and vascular endothelial growth factor expression in human endothelial cells: possible relevance to HIF-1alpha

The serine protease thrombin present at the site of vascular injury triggers fibrin formation, platelet activation and different cellular responses including angiogenesis. We report a role for thrombin in the human monolayer cultured endothelial cell growth and angiogenesis in 3D collagen gel angiogenesis assay. The angiogenic activity of thrombin is, in part, related to the expression of the vascular endothelial growth factor (VEGF)165 mRNA, assessed by reverse transcriptase-polymerase chain reaction, either in monolayer cultured endothelial cells or in endothelial cells forming capillary-like structures in the 3D collagen gel assay. This expression of VEGF mRNA is associated with a VEGF secretion in the supernatant of thrombin-treated human umbilical vein endothelial cells. The thrombin-induced VEGF165 mRNA expression is associated with the regulation of hypoxia-inducible factor 1alpha, analyzed by Western Blot, in endothelial cells.

Randomized controlled trial investigating the effect of transcervical papaverine and bupivacaine on postoperative analgesia following laparoscopic sterilization

BACKGROUND AND OBJECTIVE

A critical factor that delays patient discharge following day-surgery is severe postoperative pain and the requirement for strong analgesics. Laparoscopic sterilization is a day case procedure and is associated with additional postoperative pain compared with diagnostic laparoscopy. This pain, associated with application of Filshie clips, may be ischaemic or spasmodic in aetiology. Papaverine relaxes smooth muscle, and the aim of the study was to investigate if papaverine would be effective in improving postoperative pain if administered directly to the Fallopian tubes. Bupivacaine is used commonly in day-surgery and so we compared the effect of this local anaesthetic with saline placebo.

METHODS

Sixty-six ASA I-II females undergoing laparoscopic sterilization were entered into the prospective, randomized, double-blind, placebo-controlled clinical trial. They received intrauterine papaverine (30 mg) or bupivacaine (0.375% 30 mL) or normal saline (30 mL) via the transcervical route before application of Filshie clips.

RESULTS

There were no significant differences in the postoperative period between the three groups in the number of patients needing analgesia in the first 60 min postoperatively, the time to first analgesia, the rescue analgesic or antiemetic consumption, the incidence of postoperative nausea and vomiting, and the sedation and visual analogue pain scores.

CONCLUSIONS

From the data presented, we would not recommend routine transcervical administration of papaverine or bupivacaine for pain following laparoscopic sterilization.

Modulation of COX-2 expression by statins in human aortic smooth muscle cells. Involvement of geranylgeranylated proteins

Cyclooxygenase (COX)-2 and COX-1 play an important role in prostacyclin production in vessels and participate in maintaining vascular homeostasis. Statins are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, which is crucial in cholesterol biosynthesis. Recently, cholesterol-independent effects of statins have been described. In this study, we evaluated the effect of two inhibitors of HMG CoA reductase, mevastatin and lovastatin, on the production of prostacyclin and the expression of COX in human aortic smooth muscle cells. Treatment of cells with 25 microm mevastatin or lovastatin resulted in the induction of COX-2 and increase in prostacyclin production. Mevalonate, the direct metabolite of HMG CoA reductase, and geranylgeranyl-pyrophosphate reversed this effect. GGTI-286, a selective inhibitor of geranylgeranyltransferases, increased COX-2 expression and prostacyclin formation, thus indicating the involvement of geranylgeranylated proteins in the down-regulation of COX-2. Furthermore, Clostridium difficile toxin B, an inhibitor of the Rho GTP-binding protein family, the Rho selective inhibitor C3 transferase, and Y-27632, a selective inhibitor of the Rho-associated kinases, targets of Rho A, increased COX-2 expression whereas the activator of the Rho GTPase, the cytotoxic necrotizing factor 1, blocked interlukin-1alpha-dependent COX-2 induction. These results demonstrate that statins up-regulate COX-2 expression and subsequent prostacyclin formation in human aortic smooth muscle cells in part through inhibition of Rho.

Prognostic significance of cyclooxygenase-2 in laryngeal squamous cell carcinoma

Epidermal growth factor receptor (EGFR) overexpression is an unfavorable prognostic marker in laryngeal squamous cell carcinoma (SCC). EGFR stimulates cyclooxygenase-2 (COX-2) expression in normal human keratinocytes and squamous carcinoma cells. Based on these observations a prognostic role of COX-2 expression in laryngeal SCC can be hypothesized. Consequently, COX-2 expression was studied in laryngeal SCC (median follow-up = 47 months; range: 2-87 months) by quantitative immunohistochemistry (n = 61) and EGFR by binding assay (n = 51). Well-differentiated regions of laryngeal SCC revealed strong COX-2 immunostaining, whereas histologically normal areas neighboring tumor as well as poorly-differentiated tumors were negative. Immunohistochemical results were confirmed by Western blot analyses. Cox's regression analysis showed that the combination of low levels of COX-2 integrated density and high levels of EGFR covariates provided strong prediction, at 5-year follow-up, of both poor overall survival (chi(2) = 12.905; p = 0.0016) and relapse-free survival (chi(2) = 9.209; p = 0.01). In vitro studies on CO-K3 cell line, obtained from an EGFR positive, COX-2 negative poorly-differentiated laryngeal SCC, revealed that EGF stimulation failed to induce COX-2 expression and PGE2 production suggesting a change in EGFR signaling pathway. These findings indicate that COX-2 is overexpressed in less aggressive, low grade laryngeal SCC, whereas its expression is lost when tumors progress to a more malignant phenotype.

Prognostic significance of cyclooxygenase-2 in laryngeal squamous cell carcinoma

Epidermal growth factor receptor (EGFR) overexpression is an unfavorable prognostic marker in laryngeal squamous cell carcinoma (SCC). EGFR stimulates cyclooxygenase-2 (COX-2) expression in normal human keratinocytes and squamous carcinoma cells. Based on these observations a prognostic role of COX-2 expression in laryngeal SCC can be hypothesized. Consequently, COX-2 expression was studied in laryngeal SCC (median follow-up = 47 months; range: 2-87 months) by quantitative immunohistochemistry (n = 61) and EGFR by binding assay (n = 51). Well-differentiated regions of laryngeal SCC revealed strong COX-2 immunostaining, whereas histologically normal areas neighboring tumor as well as poorly-differentiated tumors were negative. Immunohistochemical results were confirmed by Western blot analyses. Cox's regression analysis showed that the combination of low levels of COX-2 integrated density and high levels of EGFR covariates provided strong prediction, at 5-year follow-up, of both poor overall survival (chi(2) = 12.905; p = 0.0016) and relapse-free survival (chi(2) = 9.209; p = 0.01). In vitro studies on CO-K3 cell line, obtained from an EGFR positive, COX-2 negative poorly-differentiated laryngeal SCC, revealed that EGF stimulation failed to induce COX-2 expression and PGE2 production suggesting a change in EGFR signaling pathway. These findings indicate that COX-2 is overexpressed in less aggressive, low grade laryngeal SCC, whereas its expression is lost when tumors progress to a more malignant phenotype.

Heme oxygenase-1 induction by nitric oxide in RAW 264.7 macrophages is upregulated by a cyclo-oxygenase-2 inhibitor

Unstimulated RAW 264.7 macrophages express negligible heme oxygenase-1 (HO-1) protein but incubation with the nitric oxide (NO) donor spermine nonoate (SPNO) induced HO-1 and weakly cyclo-oxygenase-2 (COX-2) protein. This effect was potentiated by coincubation with the COX-2 selective inhibitor, SC58125. Cells incubated with SPNO showed a strong increase in HO-1 mRNA levels after 4 h with a significant potentiation in the presence of SC58125, which did not modify HO-1 mRNA stability. The induction of HO-1 by NO and its potentiation by anti-inflammatory agents may play a role in inflammatory and immune responses.

Long-term management of cirrhosis. Appropriate supportive care is both critical and difficult

Orthotopic liver transplantation has emerged as an important treatment option for patients with advanced liver disease. However, each year the number of new cases of cirrhosis exceeds the number of livers available for transplantation by a factor of 5 to 10. This translates into long waiting lists and restrictive criteria for selecting transplant recipients. Until advances in surgical technique or biotechnology increase the availability of organs for transplantation, the majority of patients with advanced liver disease will have to be managed medically for years--perhaps indefinitely. Early consultation with a liver transplant center can be helpful. The transplant hepatologist and surgeon can help with triage decisions, guide workup, provide advice about patient care, optimize the timing of transplantation, offer specialized diagnostic and therapeutic options, and help the treating physician stay abreast of the continuous changes in this complex field. In the final analysis, however, it is often the skill and diligence of the primary care physician in diagnosing liver disease, identifying and treating correctable causes, optimizing the patient's health and nutrition, and anticipating and preventing catastrophic complications that determine whether the patient lives or dies.

Buscopan for the treatment of pain after laparoscopic sterilisation

We investigated the effect of Buscopan 20 mg, given at the end of surgery, on analgesic requirements in 44 ASA I and II patients presenting as day cases for laparoscopic sterilisation using Filshie clips. Patients were randomly allocated to receive either intravenous Buscopan 20 mg or saline placebo at the end of surgery. There was no significant difference in pain scores, analgesic requirements or the incidence of nausea and vomiting between the two groups. We conclude that intravenous Buscopan 20 mg was not effective for pain relief following laparoscopic sterilisation.