Mechanical control of cyclic AMP signalling and gene transcription through integrins.

This study was carried out to discriminate between two alternative hypotheses as to how cells sense mechanical forces and transduce them into changes in gene transcription. Do cells sense mechanical signals through generalized membrane distortion or through specific transmembrane receptors, such as integrins? Here we show that mechanical stresses applied to the cell surface alter the cyclic AMP signalling cascade and downstream gene transcription by modulating local release of signals generated by activated integrin receptors in a G-protein-dependent manner, whereas distortion of integrins in the absence of receptor occupancy has no effect.

The efficacy of Paclitaxel on solid tumour analysed by ATP bioluminescence assay and VEGF expression: a translational research study.

BACKGROUND: Paclitaxel (Taxol), is known to induce mitotic arrest and apoptosis by inhibiting the depolymerisation of microtubules. Tumour growth and metastasis are affected by the metabolic rate and angiogenesis. We investigated the effect of Paclitaxel on tumour metabolism and markers of angiogenesis, vascular endothelial growth factor (VEGF). MATERIALS AND METHODS: Tissue samples of 39 patients diagnosed with invasive carcinoma were obtained. The solid tumours were cultured with Paclitaxel at a concentration of 4.27 ug/ml for 24 h. The metabolic rate of the samples was measured by ATP Bioluminescence assay and the levels of VEGF in culture medium were measured by ELISA. RESULT: The mean ATP concentration of control and test groups were 7.169 and 5.004 rlu/ml, respectively, suggesting that the metabolic rate was inhibited by Paclitaxel. The mean VEGF levels in the control and test groups were 5.335 and 4.567 pg/ml, respectively. All data analysed were statistically significant (P < 0.005). The finding of the study showed that Paclitaxel could inhibit metabolic rate in solid tumour. It could also downregulate VEGF. CONCLUSION: Our result suggested that Paclitaxel is an effective cytotoxic possibly with anti-angiogenic effects.

The value of bone marrow aspirates culture for the detection of bone marrow micrometastasis in breast cancer.

BACKGROUND: Detection of micrometastasis is an important problem of clinical significance for a better understanding and control of tumor progression, which will improve patients' survival time. Tumor cells in bone marrow (BM) aspirates are indicative of the general disseminative metastasis in patients with early breast cancer and characterization of breast cancers by various tumor markers which are appropriate for the identification of high risk groups. MATERIALS AND METHODS: Bone marrow aspirates were obtained from 44 breast cancer patients at the time of surgery. To identify micrometastases in bone marrow, an immunocytochemical assay for epithelial cytokeratin (CK) was performed at the second passage after selective culture. Cytokeratin-positive bone marrow disseminated cancer cells were observed in more than 90% of the patients. This high incidence needs further investigation with bigger sample size to confirm. However, these results indicate that this technique can be used as an early diagnostic technique of bone marrow micrometastases in the patient with breast cancer thereby promoting the development of therapeutic strategy. High incidences need further investigation with bigger samples to confirm.

A rapid gas chromatographic assay for determining oxyradical scavenging capacity of antioxidants and biological fluids.

Herein, we report a new, rapid,and reliable method for measuring the protective antioxidant potential of pure antioxidant solutions or biological tissues. Peroxyl radicals generated by thermal homolysis of 2,2'-azobis-amidinopropane (ABAP) cause the oxidation of alpha-keto-gamma-methiolbutyric acid (KMBA) to ethylene; ethylene formation is monitored by gas chromatographic analysis of head space from the reaction vessel. The partial inhibition of ethylene formation in the presence of antioxidants that compete with KMBA for oxyradicals is the basis of the Total Oxyradical Scavenging Capacity Assay (TOSCA). The assay is shown to be reliable for quantifying ROS scavenging potential. The quantifiable parameters are consistent with the relative order of those predicted by the fluorescence- and oxygen electrode-based assays reported in the literature. Antioxidants competing for peroxyl radicals influenced the rate of KMBA oxidation in different ways, but the calculation of TOSC was not affected by such variations. Responses were linear over a wide range of sample concentrations and the TOSC values of classical soluble antioxidants showed the following relative order: Trolox > uric acid > ascorbic acid > GSH. The KMBA method was reliable for biological tissues; the TOSC for 1 microg rat liver cytosolic protein was 0.40 +/- 0.02 and for the microsomal membrane, 0.15 +/- 0.03. Soluble antioxidants accounted for 77% of the protective antioxidant potential in rat liver cytosol. When incorporated into the microsomal membrane, alpha-tocopherol markedly enhances antioxidant protection against peroxyl radical; thus, the assay is suitable for the assessment of fat-soluble antioxidants.

Prevalence and prevention of deep venous thrombosis of the lower extremities in high-risk pulmonary patients.

Information is lacking about the prevalence of, and the best method of preventing deep venous thrombosis (DVT) of the lower extremities in patients forty years or older with pulmonary disease that keeps them in bed for three consecutive days or more and who are thus at high risk of developing DVT or pulmonary embolism (PE). In this study, 192 high-risk patients, aged forty to ninety-two, received 125I fibrinogen and had daily radioactive scans, venous Doppler, and strain gauge plethysmography. Four preventive methods were used until patients became ambulatory: graded compression stockings (GCS) in 39, elastic bandages (EB) in 33, subcutaneous administration of 5,000 USP units of heparin (HEP) bid in 39, and oral administration of 0.5 g of acetylsalicyclic acid (ASA) bid in 35. Results were compared with those in 46 patients in a control group (CG). Twelve patients in CG, none in GCS, 4 in EB, 1 in HEP, and 2 in ASA developed DVT proved by contrast venography. There was a statistically significant difference between GCS and CG (P less than 0.0003), HEP and CG (P less than 0.0022), and ASA and CG (P less than 0.0148) but not between EB and CG (P greater than 0.10); no significant differences were found between any pair of prophylaxis groups. The significant differences could not be attributed to differences in age, sex, or length of stay in bed. PE occurred in 3 patients in CG and 1 in EB. Hemorrhagic complications occurred in 7 patients in HEP and 4 in ASA, requiring exclusion of 2 patients and 1 patient, respectively, from the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Otalgia in children.

Otalgia is a common symptom in the pediatric age group. The most common cause is acute otitis media, followed by otitis externa. In the majority of cases, the diagnosis can be established by a thorough history and a careful otologic examination. When the otologic findings are normal and the etiology is obscure, a thorough work-up to determine the source of referred pain is essential. Laboratory investigations are usually not necessary. Treatment should always be directed at the underlying cause.

Hemihypertrophy.

Hemihypertrophy refers to asymmetry of the body to a greater degree than can be attributed to normal variation. Most causes can be diagnosed from history and physical examination. Hemihypertrophy is cosmetically unsightly and the psychological impact can be quite prolonged. This article reviews the causes and differential diagnosis of hemihypertrophy and offers an approach to the management of this condition. Children with isolated hemihypertrophy are at increased risk for neoplasms. Periodic abdominal ultrasound examination and physical examination during infancy and childhood are recommended for early tumour detection.

Modulation of adhesion-dependent cAMP signaling by echistatin and alendronate.

We measured intracellular cAMP levels in cells during attachment and spreading on different extracellular matrix (ECM) proteins. Increases in cAMP were observed within minutes when cells attached to fibronectin, vitronectin, and a synthetic RGD-containing fibronectin peptide (Petite 2000), but not when they adhered to another integrin alpha nu beta 3 ligand, echistatin. Because echistatin also inhibits bone resorption, we measured the effects of adding another osteoporosis inhibitor, alendronate, in this system. Alendronate inhibited the cAMP increase induced by ligands that primarily utilize integrin alpha nu beta 3 (vitronectin, Peptite 2000), but not by fibronectin which can also use integrin alpha 5 beta 1. These results show that cell adhesion to ECM can increase intracellular cAPM levels and raise the possibility that inhibitors of osteoporosis may act, in part, by preventing activation of this pathway by integrins.