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Biomedical subjects

S Srivastava

Publications and source records attributed to S Srivastava.

At least 37 records · Page 2Linked to original sources
PubMed2006

Enhancement of chemical-oxygen demand and color removal of distillery spent-wash by ozonation.

Distillery spent-wash has very high organic content (75,000 to 125,000 mg/L chemical-oxygen demand [COD]), color, and contains difficult-to-biodegrade organic compounds. For example, anaerobic treatment of the distillery spent-wash used in this study resulted in 60% COD reduction and low color removal. Subsequent aerobic treatment of the anaerobic effluent resulted in enhancement of COD removal to 66%. In this paper, the effect of ozonation on various properties of the anaerobically treated distillery effluent, including the effect on its subsequent aerobic biodegradation, was investigated. Ozonation of the anaerobically treated distillery effluent at various ozone doses resulted in the reduction of total-organic carbon (TOC), COD, COD/TOC ratio, absorbance, color, and increase in the biochemical-oxygen demand (BOD)/COD ratio of the effluent. Further, ozonation of the anaerobically treated distillery effluent at an ozone dose of 2.08 mg/mg initial TOC and subsequent aerobic biodegradation resulted in 87.4% COD removal, as compared to 66% removal when ozonation was not used.

Aerobiosis↗
PubMed2005

Toxicity and detoxification of lipid-derived aldehydes in cultured retinal pigmented epithelial cells.

Age-related macular degeneration (ARMD) is the leading cause of blindness in the developed world and yet its pathogenesis remains poorly understood. Retina has high levels of polyunsaturated fatty acids (PUFAs) and functions under conditions of oxidative stress. To investigate whether peroxidative products of PUFAs induce apoptosis in retinal pigmented epithelial (RPE) cells and possibly contribute to ARMD, human retinal pigmented epithelial cells (ARPE-19) were exposed to micromolar concentrations of H2O2, 4-hydroxynonenal (HNE) and 4-hydroxyhexenal (HHE). A concentration- and time-dependent increase in H2O2-, HNE-, and HHE-induced apoptosis was observed when monitored by quantifying DNA fragmentation as determined by ELISA, flow cytometry, and Hoechst staining. The broad-spectrum inhibitor of apoptosis Z-VAD inhibited apoptosis. Treatment of RPE cells with a thionein peptide prior to exposure to H2O2 or HNE reduced the formation of protein-HNE adducts as well as alteration in mitochondrial membrane potential and apoptosis. Using 3H-HNE, various metabolic pathways to detoxify HNE by ARPE-19 cells were studied. The metabolites were separated by HPLC and characterized by ElectroSpray Ionization-Mass Spectrometry (ESI-MS) and gas chromatography-MS. Three main metabolic routes of HNE detoxification were detected: (1) conjugation with glutathione (GSH) to form GS-HNE, catalyzed by glutathione-S-transferase (GST), (2) reduction of GS-HNE catalyzed by aldose reductase, and (3) oxidation of HNE catalyzed by aldehyde dehydrogenase (ALDH). Preventing HNE formation by a combined strategy of antioxidants, scavenging HNE by thionein peptide, and inhibiting apoptosis by caspase inhibitors may offer a potential therapy to limit retinal degeneration in ARMD.

Aldehydes↗
PubMed2005

The prevalence of pressure ulcers in hospitalised patients in a university hospital in India.

OBJECTIVE: To estimate the prevalence of pressure ulcers in hospitalised patients and any underlying or predisposing factors to ulceration. METHOD: This cross-sectional study took place in a university hospital in Varanasi, India. A total of 445 patients hospitalised in medical and surgical wards were examined in a single day for the number, site and grade of pressure ulcers. Haemoglobin, serum albumin and blood sugar levels of patients with pressure ulcers were recorded. RESULTS: The prevalence of pressure ulcers was high (4.94%). Anaemia, malnutrition and diabetes were important risk factors, while morbidity due to pressure ulcers in long-stay wards, such as neurology, was exceptionally high (40.9%). CONCLUSION: Pressure ulcers remain one of the most neglected aspects of health-care provision in India and identifying their associated risk factors at an early stage may go a long way in preventing their occurrence.

Adult↗
PubMed2005

Effects of dengue virus infection on peripheral blood cells of mice exposed to hexavalent chromium with drinking water.

BACKGROUND & OBJECTIVE: The occupational and non-occupational exposure to hexavalent chromium Cr (VI) is common. The effect of chromium compromises the immune response of the host. Dengue virus (DV) infection causes various changes in the peripheral blood cells. It is, therefore, possible that the chromium toxicity may affect the disease process during DV infection. The present study aims to study the effects of dengue virus infection on peripheral blood cells of mice fed Cr (VI) with drinking water. METHODS: One group of mice was given ad libitum drinking water containing Cr (VI) and the other group used as the normal control mice was given plain water to drink. At the 3, 6 and 9 wk of Cr (VI) drinking, a set of mice from each group was inoculated intracerebrally (ic) with DV and studied at the 4th and 8th day post inoculation. RESULTS: It was observed that Cr (VI) drinking led to reduction in lymphocytes, haemoglobin and the haematocrit values while the granulocyte, monocyte and platelet counts were increased. On the other hand, most of the parameters were decreased following inoculation of normal mice with DV. In Cr (VI)-fed mice the effects of DV infection were minimal. The most significant finding of these experiments was that the reduction in platelet counts following inoculation with DV was markedly less in Cr (VI)-fed mice than that in DV-inoculated normal control mice. INTERPRETATION & CONCLUSION: Cr(VI) compounds have been declared as a potent occupational carcinogen. On the contrary, Cr(III) salts such as chromium polynicotinate, chromium chloride and chromium picolinate, are used as micronutrients and nutritional supplements, and have been shown to exhibit health benefits in animals and humans. Whether therapeutic doses of chromium (III) compounds may be able to prevent the DV-induced fall in platelet counts, needs to be investigated.

Administration, Oral↗
PubMed2004

In situ chromosomal localization of rDNA sites in "Safed Musli" Chlorophytum ker-gawl and their physical measurement by fiber FISH.

Fluorescence In Situ Hybridization (FISH) technique has been applied on somatic chromosomes and extended DNA fibers in the medicinally important species of Chlorophytum to elucidate physical localization and measurement of the rDNA sites using two rRNA multigene families homologous to 45S and 5S rDNA. The two species of Chlorophytum, namely C. borivillianum and C. comosum, both with 2n = 28, reveal diversity for copy number and localization of rDNA sites. C. borivillianum is comprised of five 45S-rDNA sites:one each in the secondary constriction region of chromosomes 7, 8, 9; one in the subtelomeric region of the short arm of chromosome 2 and the telomeric region of the short arm of chromosome 12; and one 5S-rDNA site in the subtelomeric region of the long arm of chromosome 1. In C. comosum, there are three 45S-rDNA sites (one each in the short arm of chromosomes 12, 13, and 14) and two 5S-rDNA sites (in the secondary constriction regions of chromosomes 2 and 13). Fiber FISH analysis conducted on extended DNA fibers revealed variation in the size of continuous tandem strings for the two r-DNA families. Taking the standard value of native B DNA equivalent to 3.27 kb for 1 mum, it was estimated that the physical size of continuous DNA strings is of the order of approximately 90 kb, 180 kb, and 300 kb for 45S-rDNA and of the order of 60 kb, 150 kb for 5S-rDNA in C. comosum, grossly in correspondence to their respective physical sizes at metaphase.

Asparagaceae↗
PubMed2004

Axillary metastases from recurrent oral carcinoma.

The rationale for surgical treatment of head and neck cancer is based on a predictable pattern of metastasis. There is aberrant or unpredictable spread rarely and typically only in recurrent disease. There are few published reports to our knowledge of axillary metastases from squamous cell cancer (SCC) of the head and neck. We present a patient who developed axillary node disease on the other side after recurrence of a squamous cell carcinoma of the floor of the mouth. She died 11 months after excision of the recurrence.

Axilla↗
PubMed2004

Emetine ditartrate: a possible lead for emergency contraception.

Interception of pregnancy in its initial stage is an attractive and viable approach to contraception. A chemical agent, taken within the first few days of missed menses, intercepts the conception, which is expelled with menstrual flow. The main targets of such agents are the uterus, blastocyst and the growing trophoblasts, whose nutritional requirement is inhibited. Our previous work has identified several nonsteroidal chemical entities as pregnancy interceptives in rodents and infrahuman primates. However, none reached clinical stage due to their ineffectiveness by oral route. Nevertheless, parallel to these rationally designed synthetic compounds, a program was ongoing to identify natural product(s) that can be used as interceptives. We are reporting for the first time the detailed profile of emetine ditartrate, a compound whose pregnancy interceptive efficacy has been studied in mouse, rat, hamster, guinea pig and rabbit by oral and intravaginal routes of administration. By the oral route, the compound caused 100% resorption of the fetuses in rat, hamster and guinea pig at 6.0, 5.0 and 3.0 mg/kg, respectively, on administration during peri- and early postimplantation periods of pregnancy (depending upon the day of implantation in each species). By intravaginal route, the compound was administered once in the form of a vaginal pessary on the day of implantation in respective species; interception of pregnancy was not achieved completely in rat and hamster at doses four to five times the oral dose in multi-day schedule. However, in guinea pig and rabbit it was fully effective at 7.0 and 70.0 mg/animal, respectively. The compound was devoid of estrogenic, antiestrogenic and progestational activity but possessed mild antiprogestational activity at the high dose in vivo. In in vitro assay, however, it did not show any significant binding to estrogen and progesterone receptors. The mode of action of the compound was found to be mainly on the uterus and early embryos around implantation, possibly on the trophoblasts and endometrial cells at the attachment site. The absence of 100% efficacy in rat and hamster by intravaginal route, but not by oral route, is possibly due to poor absorption of the compound through the vagina in these species. The guinea pig and rabbit, therefore, seem the better species for evaluating the efficacy of the compound administered by the vaginal route.

Administration, Intravaginal↗
PubMed2004

Evaluation of a surgical simulator for learning clinical anatomy.

BACKGROUND: New techniques in imaging and surgery have made 3-dimensional anatomical knowledge an increasingly important goal of medical education. This study compared the efficacy of 2 supplemental, self-study methods for learning shoulder joint anatomy to determine which method provides for greater transfer of learning to the clinical setting. METHODS: Two groups of medical students studied shoulder joint anatomy using either a second-generation virtual reality surgical simulator or images from a textbook. They were then asked to identify anatomical structures of the shoulder joint as they appeared in a videotape of a live arthroscopic procedure. RESULTS: The mean identification scores, out of a possible score of 7, were 3.1 +/- 1.3 for the simulator group and 2.9 +/- 1.5 for the textbook group (P = 0.70). Student ratings of the 2 methods on a 5-point Likert scale were significantly different. The simulator group rated the simulator more highly as an effective learning tool than the textbook group rated the textbook (means of 3.2 +/- 0.7 and 2.6 +/- 0.5, respectively, P = 0.02). Furthermore, the simulator group indicated that they were more likely to use the simulator as a learning tool if it were available to them than the textbook group was willing to use the textbook (means of 4.0 +/- 1.2 and 3.0 +/- 0.9, respectively, P = 0.02). CONCLUSION: Our results show that this surgical simulator is at least as effective as textbook images for learning anatomy and could enhance student learning through increased motivation. These findings provide insight into simulator development and strategies for learning anatomy. Possible explanations and future research directions are discussed.

Anatomy↗
PubMed2004

Traditional remedies for fertility regulation.

Plants have been used worldwide for treatment of various human ailments since antiquity. Their use is still quite prevalent in developing countries in the form of traditional/folkloric system of medicine. Intensive chemical and pharmacological studies on traditional/folkloric medicinal plants during the last 5 decades have led to the validation of traditional claims in many cases and facilitated identification of their active principles. The active principles have provided leads in the development of several life saving drugs, which are in clinical use today. A large number of these plants are used for birth control in different countries. The present review has, therefore, been planned to provide an account of the investigations carried out on traditional/folkloric plants used for fertility regulation. The status of scientific validations of their anti-fertility potential and identification of active principles during the last 28 years are discussed. The literature survey shows that approximately 318 different plants are in traditional/folkloric use worldwide, of which 227 plants are of Indian origin. So far, 74 plants have been screened for their anti-fertility potential, 48 of them have been found to be effective. Active principles of about 15 plants have been identified during the period under review.

Animals↗
PubMed2003

Two morphological types of pineal window in catfish in relation to photophase and scotophase activity: a morphological and experimental study.

The pineal window is a transparent/translucent pineal covering on the dorsal surface of the cranium of certain fishes and is associated with light reactions of fish. In the present study, catfish species Clarias batrachus, Heteropneustes fossilis, Mystus vittatus, M. seenghala, and M. cavassius were examined for the type of pineal window present. Two morphologically different types of pineal window were found: an opaque-looking pineal window in C. batrachus and H. fossilis and a translucent type of pineal window in M. vittatus, M. seenghala, and M. cavassius. The distributional pattern of pigments in the melanophores at the pineal window were studied in terms of Melanophore Index (MI). In all of the species studied, a pineal foramen, a subepidermal lens-like tissue, and pineal end vesicle were present. Experiments were carried out on catfish having the opaque pineal window, as it is uncommon in catfish. Catfish with normal and shielded pineal window were exposed to conditions of artificial constant illumination (LL) and darkness (DD) to evaluate the effects of altered photoperiods on the state of pigmentation of melanophores at the pineal window. Recordings of diel activity patterns, which are light dependent in catfish, were carried out under both natural and artificial photoperiods in fish with a normal or shielded window in order to assess its functional nature. The existence of two morphologically and functionally different types of pineal window in a relatively closely related group of catfish has been demonstrated in this study. The nature of the opaque type of pineal window has been reconsidered based on new experimental evidence.

Animals↗
PubMed2003

Influence of continuous light and darkness on the secretory pinealocytes of Heteropneustes fossilis.

In an earlier study on Heteropneustes fossilis, evidence of secretory activity in the pinealocytes had been demonstrated at the electron microscopic (EM) level and it was found to exist in two phases: a secretory phase (light cells) and a storage phase (dark cells). In the present investigation, H. fossilis was subjected to artificial photoperiods of continuous illumination and continuous darkness for a period of ten days and the effect on the secretory pinealocytes was studied at the EM level. Marked results were observed within the short period of ten days emphasizing the role of environmental photoperiod on the secretory activity of the pinealocytes. During continuous illuminated phase, both light and dark cells were observed: the light cells showed intense secretory activity and dark cells a storage one. During the dark phase both types of cells were present but in different metabolic states and neither of the cells demonstrated synthetic nor storage activity. Light cells were metabolically active but not secretory active and dark cells showed a necrotic condition. Phagocytotic activity of the dark cells was also seen. Intense neural activity was also observed during exposure to both the artificial photoperiods. The results highlight the role of light on the secretory activities of the pinealocytes of the catfish pineal organ.

Animals↗
PubMed2003

[Ankle arthrodesis with intramedullary compression nailing].

Tibiotalar arthrodesis still remains the primary choice of treatment for disabling ankle arthropathy since the results of ankle arthroplasty are not yet convincing. Numerous operative techniques have been described, with an increasing trend towards the use of internal fixation and compression. Using an intramedullary compression nailing technique, 137 tibiotalar fusions were performed at our hospital. The special design of the nail allows distal interlocking in the talus and dynamic axial compression with high primary stability. With correct joint axis, only the cartilage joint surfaces were removed. For axis correction the corresponding bony joint surfaces were also resected. We also performed a dowel technique with bone grafting from the lateral malleolus. We examined 110 of the 137 patients during follow-up. A primary union could be achieved in 99 cases (90.0%). A further six cases (5.5%) healed after recompression and bone grafting. Nonunion remained in five cases (4.5%). Operative complications included one tibial shaft fracture and one hematoma. Septic complications were three superficial and eight deep infections. Sufficient pain relief after arthrodesis was reported by 70 (63.6%) patients; in 37 (33.6%) patients the symptoms remained unchanged and 3 (2.7%) patients found their pain to be worse than before the procedure. Intramedullary compression nailing is shown to be an effective technique for tibiotalar arthrodesis in severe ankle arthropathy. The main advantages of the technique are limited soft tissue damage in the ankle area and high primary stability allowing early weight bearing.

Adult↗
PubMed2003

Malignant change after 18 months in a lower limb ulcer: acute Marjolin's revisited.

Lower limb ulcers present a common clinical problem and are at risk of malignant change. A Marjolin's ulcer has traditionally been regarded as malignant change in a long standing ulcer and/or scar tissue. We report a case of Marjolin's degeneration that developed in an ulcer only 18 months following the initial injury. Such a short latent period has not been reported for over 70 years. This report highlights the possibility of early Marjolin's change and we propose a ranked diagnostic screen to aid in early identification of possible malignant change, based on the current published evidence.

Aged↗
PubMed2003

p53 Immunostaining guided laser capture microdissection (p53-LCM) defines the presence of p53 gene mutations in focal regions of primary prostate cancer positive for p53 protein.

OBJECTIVES: A wide range of p53 mutations (5-65%), detected by various methods, has been reported in primary prostate cancers (CaP). IHC staining of radical prostatectomy specimens shows marked heterogeneity of focally distributed p53-positive cells. However, a significant relationship between the focal staining of p53 and cancer recurrence after radical prostatectomy has been noted. Increased frequency of p53 mutations has been generally observed in advanced stage CaP and metastatic prostate cancer cell lines. The significance of focal p53 immunostaining in primary CaP remains uncertain with respect to the p53 gene mutation or tumor progression. The goal of this study was to evaluate p53 gene mutations in focal regions of primary prostate cancers positive by p53 immunostaining. METHODS: Whole-mount prostates from men with clinically organ-confined prostate cancer were immunostained for p53 protein. Laser capture microdissection (LCM) was used to harvest p53 positive cells from areas of tumor and prostatic intraepithelial neoplasia and benign gland. DNA from microdissected cells were amplified for p53 exons 5-8 by polymerase chain reaction (PCR) and analyzed for mutations by single strand conformation polymorphism and DNA sequencing. Mutation analysis of the p53 gene exons 5-8 was performed in the p53 immunostaining positive focal regions (1+ to 4+) of whole-mount prostate sections from 16 patients. RESULTS: Of 16 patients with p53 IHC positive tumors, 11 (69%) had p53 gene mutations as determined by DNA sequence analysis. However, randomly microdissected tumor cells from 4 of 18 patients (22%) negative for p53 IHC also demonstrated mutations in the p53 gene. A significant fraction of prostate tumors with focally positive immunostaining for p53 have been confirmed to contain mutations in the p53 gene. CONCLUSIONS: p53 immunostaining guided LCM combined with DNA-based analyses emphasizes the presence of focal p53 mutations in primary prostate cancers and underscores the significance of previous observations showing a correlation between focal p53 immunostaining in primary CaP and cancer recurrence after radical prostatectomy.

Base Sequence↗