Evaluation of phytochemical-incorporated porous polymeric sponges for bone tissue engineering: a novel perspective.

Porous polymeric scaffolds are extensively studied for delivery of bone growth factors. Since phytochemicals are known to produce changes in cell signalling and other metabolic pathways, osteogenic phytochemicals, that is, extracts of Cissus quadrangularis and Butea monosperma, are incorporated into sulphonated poly(aryl ether ketone) sponges. The results have shown that the scaffolds with phytochemicals enhanced the proliferation and alkaline phosphatase activity of the cells compared to cells treated on scaffolds without phytochemicals. Hence, these phytochemicals can be evaluated to augment, if not substitute the use of bone morphogenetic proteins in scaffolds.

Biomimetic mineralization of novel silane crosslinked collagen.

Studies on the mechanisms of mineralization of connective tissues, have gained momentum in the recent past. In the present study, Biomimetic mineralization of modified fish scale collagen in vitro is reported. The fish scale collagen was crosslinked with 3-Aminopropyl triethoxysilane and the crosslinked collagen (FCSi) was characterized using conventional methods. The biomimetic mineralization capacity of FCSi was evaluated in SBF solution for 7 days. Formation of hydroxyapatite crystals on the matrix in vitro has been confirmed by FTIR, XRD and SEM-EDAX techniques. The FCSi may be used as a scaffold in bone tissue engineering and as an osteoinductive material in experimental animal models before applying clinically.

Fluorescence quenching of substituted polyperylene with functionalized polythiophenes.

The present investigation focuses the influence of polythiophene i) containing hetero aromatic structures and ii) containing mesogenic groups towards the photoluminescence properties of substituted polyperylene (PPE). The structural contribution towards the optical properties was individually discussed. The photoluminescence of PPE was quenched to the maximum level (30%) when it was blended with polythiophene with mesogenic groups containing longer alkyl spacer. Results of the same blend in solid-state shows 85% of PL quenching.

Molecular orbital calculations on polythiophenes containing heterocyclic substituents: effect of structure on electronic transitions.

Molecular orbital calculations have been performed on thiophene oligomers bearing heterocyclic substituents at the third position in order to understand the interplay of effects such as the nature of substituent, skeletal substitution pattern, heteroatom identity, etc. on electronic transitions. The geometry optimization was carried out using the semiempirical AM1 method, and the electronic transitions predicted for the oligomers were extrapolated for polymers using an oligomeric approach. The experimentally determined optical transitions were found to follow the predicted trend of electronic transitions of monomers and polymers.

Quantum chemical studies on polythiophenes containing heterocyclic substituents: effect of structure on the band gap.

Color tuning by the tailoring of substituents at the 3-position of thiophene is very encouraging, and comparative experimental and theoretical studies proved to be powerful in the search for a suitable design for the above. Since the novel polythiophene-based materials substituted with five-membered/six-membered ring containing sulphur and nitrogen at different positions are proven to be potential candidates for electron-transporting hole blocking functions, the structure-property relationship of these systems have been focused in the present study. Molecular-orbital calculations are applied to obtain the optimized geometries and band gaps of the thiophene oligomers. An oligomeric approach has been implemented for calculating the band gaps, and the theoretically obtained band gaps for the different model compounds are compared. Density-functional theory B3LYP6-31G* predicted band-gap values are compared with the experimental band gaps obtained from optical-absorption edge. The predicted values show little deviations from experimental band gaps, but the trend in band gap is found to be the same in experimental and theoretical results in most of the cases. Hence, this study illustrates the usefulness of quantum-mechanical calculations in understanding the effects of various structural parameters on optical band gap.

A comparison between 24-hour and 2-hour urine collection for the determination of proteinuria.

Proteinuria is one of the fundamental criteria for the diagnosis of pre-eclampsia with quantitative assessment based on the 24-hour urine protein estimation as the gold standard. This study was undertaken to determine whether a 2-hour protein estimation correlated with that of a formal 24-hour collection. Thirty women with proteinuric hypertension were recruited. There was significant correlation between the 2-hour and 24-hour urine protein levels (Pearson's correlation coefficient 0.76 (P 0.000). A positive 2-hour test was associated more closely with significant levels of 24-hour proteinuria than dipstick analysis alone. We conclude from this study that a random 2-hour sample could be used for the initial assessment of proteinuria and so avoid the delay associated with 24-hour quantification of urinary protein.

Reversible non enhancing lesions without focal neurological deficits in eclampsia.

Nine patients with eclampsia, were subjected to computerized tomographic scan (CT scan) of the head to ascertain the changes in the brain that accompany seizures and encephalopathy of eclampsia. Only those patients who had a seizure within the past 24 h were included in this study. None of the patients had any focal neurological deficit. Six of the nine patients had abnormal findings on CT scan consisting of multiple non enhancing hypodensities in the cerebral white matter. One patient also had subependymal haemorrhage over the lateral ventricle. These changes were found to have disappeared when the CT scan was repeated on the seventh day. There was no correlation between the mean arterial blood pressure or the number of seizures and the presence of hypodensities in the brain. These findings suggest that subclinical changes in the form of reversible hypodensities and rarely bleeding can occur in eclampsia even when patients have no focal neurological deficits. It appears that these lesions represent focal areas of cerebral oedema, secondary to failure of autoregulation of cerebral blood flow.

Interictal EEG changes in eclampsia.

The pathogenesis of seizures and encephalopathy in eclampsia remains obscure even today. There are only a few reports on EEG findings in eclampsia. This is a report of the interictal EEG changes in 8 patients with eclampsia who were evaluated prospectively. The major EEG changes observed were (1) slowing of the background activity (generalized slowing in 4 patients and focal slowing in 3 patients) and (2) intermittent spike and sharp wave transients (5 patients). These abnormalities had disappeared in all except 2 patients when the EEG was repeated on the seventh day. A comparison is drawn between eclampsia and hypertensive encephalopathy for the clinical, EEG and CT/MRI findings. The pathogenesis of seizures and encephalopathy could be similar in these two conditions. It is worth while considering these EEG changes while planning the treatment of eclampsia.