MMP-9 gene ablation mitigates hyperhomocystenemia-induced cognition and hearing dysfunction

Hyperhomocysteinemia (HHcy) is associated with cognitive decline and hearing loss due to vascular dysfunction. Although we have shown that HHcy-induced increased expression of matrix metalloproteinase-9 (MMP-9) is associated with cochlear pathology in cystathionine-β-synthase heterozygous (CBS^+/?) mice, it is still unclear whether MMP-9 contributes to functional deficit in cognition and hearing. Therefore, we hypothesize that HHcy-induced MMP-9 activation causes vascular, cerebral and cochlear remodeling resulting in diminished cognition and hearing. Wildtype (WT), CBS^+/?, MMP-9^?/? and CBS^+/?/MMP-9^?/? double knock-out (DKO) mice were genotyped and used. Doppler flowmetry of internal carotid artery (ICA) was performed for peak systolic velocity [PSV], pulsatility index [PI] and resistive index [RI]. Cognitive functions were assessed by Novel Object Recognition Test (NORT) and for cochlear function Auditory brainstem response (ABR) was elicited. Peak systolic velocity, pulsatility and resistive indices of ICA were decreased in CBS^+/? mice, indicating reduced perfusion. ABR threshold was increased and maximum ABR amplitude and NORT indices (recognition, discrimination) were decreased in CBS^+/? mice compared to WT and MMP-9^?/?. All these parameters were attenuated in DKO mice suggesting a significant role of MMP-9 in HHcy-induced vascular, neural and cochlear pathophysiology. Regression analysis of PSV with ABR and cognitive parameters revealed significant correlation (0.44–0.58). For the first time, MMP-9 has been correlated directly to functional deficits of brain and cochlea, and found to have a significant role. Our data suggests a dual pathology of HHcy occurring due to a decrease in blood supply (vasculo-neural and vasculo-cochlear) and direct tissue remodeling.     

Multimeric bivalent immunogens from recombinant tetanus toxin H<Subscript>C</Subscript> fragment,synthetic hexasaccharides,and a glycopeptide adjuvant

Using recombinant tetanus toxin H_C fragment (rTT-H_C) as carrier, we prepared multimeric bivalent immunogens featuring the synthetic hexasaccharide fragment of O-PS of Vibrio cholerae O:1, serotype Ogawa, in combination with either the synthetic hexasaccharide fragment of O-PS of Vibrio cholerae O:1, serotype Inaba, or a synthetic disaccharide tetrapeptide peptidoglycan fragment as adjuvant. The conjugation reaction was effected by squaric acid chemistry and monitored in virtually real time by SELDI-TOF MS. In this way, we could prepare well-defined immunogens with predictable carbohydrate–carrier ratio, whose molecular mass and the amount of each saccharide attached could be independently determined. The ability to prepare such neoglycoconjugates opens unprecedented possibilities for preparation of conjugate vaccines for bacterial diseases from synthetic carbohydrates.     

Effects of cadmium chloride on ovulation and on induction of sterility in the female golden hamster

The effects of single subcutaneous injections of cadmium chloride (CdCl2) on ovulation, egg transport and early pregnancy in the golden hamster were studied. While a single dose of 1.25 or 2.5 mg/kg of CdCl2 imposed none to marginal effects, hamsters treated with 5 or 10 mg/kg CdCl2 experienced a period of sterility ranging from 11-69 (5 mg/kg) or 46-71 (10 mg/kg) days, followed by a normal pregnancy. Administration of CdCl2 also induced ovulation inhibition which was dose-and time-dependent. A minimum dose of 5 mg/kg CdCl2 was needed to inhibit ovulation. When CdCl2 was given closer to the time of the luteinizing hormone (LH) surge on the day of proestrus, a more pronounced effect on ovulation was recorded. The incidence of failure of ovulation was associated with decreased progesterone levels in serum and inflammation, hemorrhages and necrosis in the ovary. However, the ovarian lesions lasted less than 4 days. The results indicate that CdCl2 inhibits ovulation when administered close to the time of ovulation, whereas its influence on pregnancy is pronounced but temporary.     

Role of Liv-52 in protection against beryllium intoxication

An ayurvedic medicine, Liv-52, was studied as a prophylactic agent against beryllium-induced toxicity in rats. Administration of berylliumper se caused severe degenerative and necrotic changes in kidneys, liver, and uterus. Beryllium exposure also reduced glycogen content, activities of alkaline phosphatase, succinate-dehydrogenase, and adenosine-triphosphatase in these organs. On the contrary, activities of acid phosphatase and glucose-6-phosphatase showed marginal increase. Liv-52-primed rats exhibited comparatively less marked toxic effects.     

Antioxidant and Antidiabetic Properties of Extracts from Three Underutilized Food Plants of North East India

Three underutilized leafy vegetables Sarcochlamys pulcherrima (Roxb.) Gaudich (SP), Ipomoea aquatica Forssk. (IA) and Zanthoxylum rhetsa (Roxb.) DC (ZR) were extracted with different solvents viz. 95 % ethyl alcohol, methanol and hot water. The extracts were evaluated for their antioxidant potential via DPPH, ABTS and FRAP assay along with electroanalytical studies using cyclic voltammetry. The antidiabetic potential was determined by recording their α-amylase and α-glucosidase inhibitory assay. The total phenolic content (TPC), total flavonoid content (TFC) and the liquid chromatography-mass spectrometry (LC/MS) based phytochemical profiles of the extracts were also determined. All three extracts of SP exhibited significant antioxidant capacity. The antidiabetic potential of the IA and ZR extracts was found to be higher than or at par with that of standard acarbose. LC/MS studies reveal the presence of hitherto reported antioxidant and antidiabetic compounds like gamma-aminobutyric acid, cinnamic acid, caffeic acid, α-viniferin, piperlonguminine, niacin, kaempferol, etc., in the extracts.     

Protein fractionation using electrostatic interactions in membranel filtration

One of the critical factors limiting the development of membrane systems for protein fractionation has been the poor selectivity that has generally been obtained with these membrane devices. We have demonstrated that it is possible to dramatically improve the selectivity of available membrane systems by exploiting the different electrostatic interactions between the two proteins and the membrane. The separation factor for the albumin-hemoglobin system could be increased to more than 70 simply by reducing the salt concentration and adjusting the pH to around 7 (near the isoelectric point of hemoglobin). This very high selectivity was a direct result of the strong electrostatic exclusion of the charged albumin from the membrane pores under these conditions. This high selectivity makes it possible to very effectively separate these albumin-hemoglobin mixtures using membrane filtration, and this was demonstrated experimentally using both a simple batch filtration process and a continuous diafiltration system. The hemoglobin recovery in the diafiltration experiment was greater than 70% after a 3-diavolume filtration, with the Hb purification factor being around 100 under these conditions. These results clearly demonstrate the potential of membrane systems for the fractionation of proteins even with very similar molecular weights. (c) 1995 John Wiley & Sons, Inc.     

Cloning of tetracycline-resistance genes from various strains of Clostridium perfringens and expression in Escherichia coli.

One hundred strains of Clostridium perfringens and 52 strains of other clostridia of human and animal origins were screened for tetracycline resistance. Fifty-six strains were resistant to tetracycline in the C. perfringens group. Ten strains were selected for their high level of resistance. In all of them, the tetracycline-resistance genes were found to be residing in large plasmids of about 50 kb, all showing homologies. Several tetracycline-resistance genes from plasmids of various strains of C. perfringens were cloned in plasmid pUC19 and the resistance was expressed in Escherichia coli. Hybridization analysis showed these genes to be homologous among themselves and also to tetP gene from the PCW3-type plasmid.     

The hypothalamo-neurohypophysial system in Indian fresh-water goby, Glossogobius giuris (Ham.)

The hypothalamo-neurohypophysial neurosecretory system in Indian fresh-water goby, Glossogobius giuris (Ham.) has been described. The tractus preoptico-hypophyseus serves the function of a morphological and physiological connection between the hypothalamus and pituitary gland. In addition to main mass of the nucleus preopticus cells (cystine/cysteine bearing), a group of few cells in the hypothalamus has also been observed. These cells are situated posterior to the position of the nucleus preopricus and are CH Ph + ve and AF + ve. The neurosecretory material in the cells of nucleus preopticus is in the form of fine granules. The nucleus lateralis tuberis is absent in the fish under study. The disposition of neurosecretory material is heaviest along the fibres of the neurohypophysis in the region of pars intermedia with which it forms a profuse interdigitation. The fibres usually terminate over the blood vessels. The Herring bodies are noticeable at different levels in the neurohypophysis and pars-distalis. Besides the neurosecretory fibres, Herring bodies, non-stainableneurosecretory fibres and blood vessels, the pituicytes are also present in the neurohypophysis (SAKSENA 1974a, b). The intraaxonal flow of neurosecretory material, the vascularization of the nucleus preopticus and hypothalamo-hypophysial regulatory mechanism have been also discussed.