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Biomedical subjects

S Shukla

Publications and source records attributed to S Shukla.

At least 19 recordsLinked to original sources
PubMed2003

Effect of glial cell line-derived neurotrophic factor (GDNF) co-transplantation with fetal ventral mesencephalic cells (VMC) on functional restoration in 6-hydroxydopamine (6-OHDA) lesioned rat model of Parkinson's disease: neurobehavioral, neurochemical and immunohistochemical studies.

Among trophic factors already known, glial cell line-derived neurotrophic factor (GDNF) and other members of its family have potent and specific action on dopaminergic neurons. In the present investigation an attempt has been made to validate the role of GDNF co-transplantation with fetal ventral mesencephalic cells (VMC) on functional viability and restoration using neurobehavioral, neurochemical and immunohistochemical parameters at 6 weeks post-transplantation in 6-hydroxydopamine (6-OHDA) lesioned rat model of Parkinson's disease (PD). A significant restoration (P<0.01) in D-amphetamine induced rotations, spontaneous and apomorphine induced locomotor activity in rats co-transplanted with VMC and GDNF was observed as compared to VMC alone transplanted rats. Level of dopamine (DA), 3,4-dihydroxy-phenyl acetic acid (DOPAC) and dopamine D2 (DA-D2) receptors in the caudate putamen (CPu) were significantly (P<0.001) restored in co-transplanted group as compared to VMC transplanted or GDNF administered animals. The functional viability of transplanted VMC was confirmed by tyrosine hydroxylase (TH) expression and quantification of TH-positive cells by image analysis revealed a significant restoration in TH-IR fibers density as well as TH-IR neurons counts in co-transplanted animals over VMC transplanted animals. Results suggest that co-transplantation of VMC and GDNF may be a better approach towards functional restoration in 6-OHDA lesioned rat model of Parkinson's disease.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2003

Perceptual indicators of environmental health, future land use, and stewardship.

There are important linkages between the health of humans and the environment, restoration of degraded lands, and long-term stewardship of public lands, yet most environmental indicators deal only with assessing the physical and biological aspects of ecosystems. In this article, we examine the ratings of perceptions of several environmental problems for their utility as indicators of environmental quality, and examine perceptions of future land use by people interviewed in Santa Fe, New Mexico, near the Department of Energy's (DOE) Los Alamos National Laboratory (LANL). Overall, people with lower incomes rated environmental problems as more severe than others, were more willing to spend federal funds to solve them, and were consistent in their ratings of severity of environmental problems and their willingness to spend federal funds. Cleaning up LANL and other Department of Energy sites, received the highest rating for expenditure of federal funds. The highest rated future uses for DOE sites were for recreation and for National Environmental Research Parks. People with less education generally gave higher ratings to most future land uses for DOE than did those with more education. However, those with higher education gave higher ratings to nuclear reprocessing, and nuclear material storage. Where there were differences, the people interviewed at Santa Fe rated all environmental problems (except pesticides) as more severe than did those previously interviewed in Albuquerque (located farther from the LANL site), and they were more willing to spend federal funds on these problems. Ratings for all future land uses did not differ between the Santa Fe and Albuquerque respondents. These perception-based indicators show general agreement among people living close and farther away from LANL with respect to cleaning up LANL and the future land uses for the site. These indicators should be considered by regulators, site personnel, and policy makers in future management and land use decisions.

Adult↗
PubMed2003

Prediction of beta-turns from amino acid sequences using the residue-coupled model.

We evaluated the prediction of beta-turns from amino acid sequences using the residue-coupled model with an enlarged representative protein data set selected from the Protein Data Bank. Our results show that the probability values derived from a data set comprising 425 protein chains yielded an overall beta-turn prediction accuracy 68.74%, compared with 94.7% reported earlier on a data set of 30 proteins using the same method. However, we noted that the overall beta-turn prediction accuracy using probability values derived from the 30-protein data set reduces to 40.74% when tested on the data set comprising 425 protein chains. In contrast, using probability values derived from the 425 data set used in this analysis, the overall beta-turn prediction accuracy yielded consistent results when tested on either the 30-protein data set (64.62%) used earlier or a more recent representative data set comprising 619 protein chains (64.66%) or on a jackknife data set comprising 476 representative protein chains (63.38%). We therefore recommend the use of probability values derived from the 425 representative protein chains data set reported here, which gives more realistic and consistent predictions of beta-turns from amino acid sequences.

Algorithms↗
PubMed2003

Prediction of gamma-turns from amino acid sequences.

We predicted gamma-turns from amino acid sequences using the first-order Markov chain theory and enlarged representative data sets corresponding to protein chains selected from the Protein Data Bank (PDB). The following data sets were used for training and deriving the probability values: (1) an initial data set containing 315 protein chains comprising 904 gamma-turns and (2) a later data set in order to include new entries in the PDB, containing 434 protein chains and comprising 1053 gamma-turns. By excluding 93 protein chains that were common to these two training data sets, we generated two mutually exclusive data sets containing 222 and 341 protein chains for testing our predictions. Applying amino acid probability values derived from training data sets on to testing data sets yielded overall prediction accuracies in the range 54-57%. We recommend the use of probability values derived from the data set comprising 315 protein chains that represents more gamma-turns and also provides better predictions.

Amino Acid Sequence↗
PubMed2003

Role of Ca2+ in radiation-induced damage in murine splenocytes.

PURPOSE: To address the links between calcium, peroxidation, cell damage and death and the response of the enzymes involved in free radical metabolism, in splenocytes of mice irradiated with gamma-rays. MATERIALS AND METHODS: Splenocytes of Swiss albino mice were irradiated with various doses (0-7 Gy) of gamma-rays (60Co) at a dose-rate of 0.0575 Gy s(-1). Membrane peroxidation and fluidity were determined by the thiobarbituric acid-reactive substances (TBARS) method, and fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH), respectively. Apoptosis was analysed by nucleosomal ladder formation and activity of NF-kappaB by electrophoretic mobility shift assay (EMSA). The specific activities of the antioxidant enzymes, lactate dehydrogenase (LDH), levels of nitric oxide (NO*) and glutathione were determined spectrophotometrically. Modulatory effects of Ca2+ were examined at 3 Gy using different concentrations (1, 3 and 5 mM) in the presence or absence of the ionophore A23187. RESULTS: Irradiation of splenocytes resulted in enhanced peroxidative damage. membrane fluidity, apoptosis and DNA binding activity of NF-kappaB. The specific activities of LDH and antioxidant enzymes superoxide dismutase (SOD), DT-diaphorase (DTD), glutathione S-transferase (GST) and levels of glutathione (GSH) and NO* were increased with radiation dose up to 4Gy. Ca2+ augmented the radiation-induced responses. The presence of ionophore A23187 potentiated the modulatory effects of Ca2+. CONCLUSIONS: These findings show that Ca2+ augments radiation damage and is more effective intracellularly. Ca2+, peroxidation, cellular damage and apoptosis are possibly interlinked through signals, as is evident from the increased activity of NF-kappaB and generation of NO*. The enhanced antioxidant status suggests an attempt made by the irradiated cells to maintain their normal functions.

Animals↗
PubMed2003

Perceptions of recreational fishing boat captains: knowledge and effects of fish consumption advisories.

The impacts of fish consumption advisories on recreational and subsistence fishing, particularly in fresh waters, have been examined extensively. By contrast, little attention has focused on organized recreational fishing, such as from party and charter boats, and particularly for salt water fish. We interviewed 93 New Jersey boat captains to determine their knowledge about fish consumption advisories, and whether, in their opinion, clients knew of fish consumption advisories, and whether they thought advisories had an effect on recreational fishing and their businesses. Advisories were ranked by captains as a moderate influence on the success of their business, less so than number of fish caught, strength of the economy, overfishing by commercial boats, and management regulations. Only one boat captain had not heard warnings about eating fish, but what captains said they had heard was mixed in its accuracy and completeness. Clients expect captains to know about fish, and about half of boat captains said clients had asked about the safety of eating fish. Captains who felt advisories were affecting their businesses tended to fish for species without high levels of mercury (except for bluefish) or PCBs, the primary contaminants of concern for state advisories and federal advice. However, these captains worked closer to areas (e.g., Raritan Bay complex and New York Harbor) subject to advisories than did other captains, and were more prone to say that management regulations (e.g., fish size, creel limits, seasons) and marketing and advertising by the industry or state were strong influences on the success of their seasons. Comparing captains who thought advisories had some or great effect (60%) versus those reporting "no effect" (40%), there was no difference in the mean percentage of trips targeting high mercury species such as swordfish and shark. Many captains said they would or might post advisories, but 42% of the boat captains said they would not post consumption warnings if the state provided them. The significant portion (at least 15%) of saltwater fishing supported by these businesses suggests that these captains are an important conduit for future risk communication.

Animals↗
PubMed2002

Exposure of South Carolinians to commercial meats and fish within their meat and fish diet.

There has been considerable interest in the public's exposure to a variety of contaminants through the consumption of wild fish and game, yet there is little information on consumption of commercial meats and fish, or the relationship between commercial and self-caught fish. We conducted a dietary survey in 1999 to estimate exposure levels of 464 individuals from people attending the Palmetto Sportsmen's Classic. Mean consumption was similar for beef, chicken/turkey, and wild-caught fish, and much lower for pork and store-bought fish, and still lower for restaurant fish. There were no ethnic differences in the consumption of most commercial fish and meats, although the differences for chicken approached significance. There were significant ethnic differences in consumption of wild-caught fish. Women ate significantly less of all meat types, except store-bought fish. People over 45 ate less beef than younger people, and people younger than 32 ate significantly more chicken than others. There were no significant differences in consumption patterns as a function of income, except for chicken and wild-caught fish; people with higher incomes ate more chicken than others, and people with lower incomes ate more wild-caught fish than others. When all wild-caught and commercial fish and meats are considered, there are significant differences only for ethnicity and gender. Blacks consume significantly more fish than Whites, and men consume significantly more than women.

Adult↗
PubMed2002

Metal levels in raccoon tissues: differences on and off the Department of Energy's Savannah River Site in South Carolina.

Levels of arsenic, cadmium, chromium, copper, lead, manganese, selenium, and strontium88 were examined in heart, kidney, muscle, spleen and liver of raccoons (Procyon lotor) from four areas on the Department of Energy's Savannah River Site (SRS), including near a former reactor cooling reservoir and a coal ash basin, and from public hunting areas within 15 km of the site. Mercury is mentioned briefly because it is discussed more fully in another paper. We test the hypotheses that there are no differences in metal levels between raccoons on SRS and off the SRS (off-site), and among different locations on the SRS. Although raccoons collected off-site had significantly lower levels of mercury and selenium in both the liver and kidney, there were few consistencies otherwise. There were significantly higher levels of cadmium in liver of on-site compared to off-site raccoons, and significantly higher levels of chromium and strontium88 in kidney of on-site compared to off-site raccoons. Copper and manganese were highest in the liver; cadmium, lead, mercury and selenium were highest in the liver and kidney; chromium was highest in the spleen and muscle; arsenic was highest in the heart, and strontium88 was slightly higher in the kidney than other organs. Where there were significant differences on site, chromium, manganese were highest in raccoon tissues from Steel Creek; arsenic, lead and selenium were highest in the Ash Basin; cadmium was highest at Upper Three Runs; and strontium88 was highest at Upper Three Runs and Steel Creek. The patterns were far from consistent.

Animals↗
PubMed2001

Metals in feathers of sooty tern, white tern, gray-backed tern, and brown noddy from islands in the North Pacific.

Levels of heavy metals are usually higher in adult than young birds because they eat larger, more contaminated prey, or because they have had longer to accumulate metals in their tissues. Further, levels of contaminants are usually less in birds nesting on remote, offshore islands than in birds breeding closer to mainland areas that are urbanized and industrialized. We examined the feather levels of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in adult sooty terns (Sterna fuscata), gray-backed terns (Sterna lunata), and brown noddy (Anous stolidus, and adult and young white terns (Gygis alba, from Midway Atoll, and in adult and young sooty terns and adult brown noddy from Manana Island, Hawaii (chicks of other terns were not available). We tested and rejected the null hypotheses that metal levels are not significantly different among species, ages, and locations. Despite their small size, adult white terns had the highest levels of lead, arsenic and tin. Brown noddies had the highest levels of cadmium, chromium, manganese, and selenium. Sooty and white terns had the highest levels of mercury. Sooty tern adults had significantly higher levels of cadmium, mercury, and selenium than young, while young had significantly higher levels of arsenic and manganese. White tern adults had significantly higher levels of selenium and tin than young, while young had higher levels of cadmium and mercury than adults. Except for mercury, there were significant inter-location differences within species in all heavy metals. Contrary to expectation, where the differences were great, metals generally were higher in the feathers of terns and noddies from Midway than from Manana.

Age Factors↗
PubMed2001

Posterolateral tunnels and ponticuli in human atlas vertebrae.

The posterolateral tunnel on the superior surface of the first cervical (atlas) vertebra is of normal occurrence in monkeys and other lower animals, but its presence in the form of a tunnel-like canal, for the passage of the third part of the vertebral artery over the posterior arch of the human atlas vertebra is not reported. The aim of the present study was to detect the presence of such a canal, in addition to other types of ponticuli (little bridges) reported by earlier investigators, in macerated atlas vertebrae and routine cadaveric dissections. The posterolateral tunnel was detected in 1.14%, and the posterior and lateral ponticuli in 6.57 and 2% of vertebrae. Probably the bony roof of the posterolateral tunnel serves the purpose of additional lateral extension for the attachment of the posterior atlanto-occipital membrane in quadrupeds, where the load of the head is supported by the extensor muscles of the neck, ligaments and posterior atlanto-occipital membrane. In man, where the weight of the head is borne by the vertical loading of the superior articular process of the atlas, the roof of the tunnel has disappeared.

Adult↗
PubMed2001

Synthesis and characterization of nanocrystalline silver coating of fly ash cenosphere particles by electroless process.

Electroless nanocrystalline Ag coating of fly ash cenosphere particles utilizing a Sn-Pd catalyst system is demonstrated in this article. The deposition of pure metallic nanocrystalline Ag on the fly ash cenosphere particle surface is confirmed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analysis. Under the described conditions of electroless coating, average nanocrystalline Ag-coating thickness is observed to be approximately 220 nm, using a focused ion beam technique, which is less than that observed by transmission electron microscopy (TEM) (260-360 nm). TEM observation further reveals that the Ag-coating is made up of 50 nm Ag nanocrystallites, which is comparable with the size of approximately 37 nm obtained from the XRD data. The mechanism of the electroless Ag-coating process is discussed. Ag-coated fly ash particles find applications in manufacturing conducting polymers for electromagnetic interference shielding applications.

Carbon↗
PubMed2000

Effect of calcium channel blockers on baroreceptor reflex in anaesthetized cats.

The baroreflex-induced changes in heart rate in chloralose anaesthetized and artificially ventilated cats (2.5-4.0 kg) before and after pretreatment with calcium channel blockers (CCBs) were compared. Baroreflex mediated changes in heart rate (HR) were elicited by raising and lowering the systemic blood pressure with intravenous injections of phenylephrine and sodium nitroprusside, respectively. The effects of three CCBs, verapamil, diltiazem and nifedipine administered either intravenously (i.v.) or intracisternally (i.c.) were studied. Verapamil administration markedly inhibited the reflex bradycardia as well as the tachycardia following either i.v. or i.c. administration. Intracisternally, a relatively smaller dose of verapamil produced an effect comparable in magnitude and duration, to a higher i.v. dose. The reflex bradycardia was inhibited following i.v., but not i.c. administration of nifedipine while the reflex tachycardia was not affected significantly by either i.v. or i.c. nifedipine. Intravenous diltiazem did not appear to affect the reflex bradycardia or tachycardia significantly. It is suggested that verapamil administration interacts with central cardiovascular integrating mechanisms to reduce the gain of the baroreflex function. Nifedipine and diltiazem are relatively free from this effect.

Animals↗
PubMed2000

Factors influencing pain outcome in herpes zoster: an observational study with valaciclovir. Valaciclovir International Zoster Assessment Group (VIZA).

AIM OF THE STUDY: An observational study with valaciclovir was conducted to assess clinical outcome in herpes zoster, especially pain and associated neurological signs and symptoms in relation to a series of demographic and disease characteristics discernible at presentation. The safety and acceptability of valaciclovir for treatment of zoster was assessed in a wide variety of primary care and clinic referral settings. METHODS: In total, 1897 immunocompetent adults with clinically diagnosed, localized acute herpes zoster were enrolled in this international, open-label study of valaciclovir. All subjects received treatment with oral valaciclovir (1000 mg three times daily) for 7 days from entry to the study and were asked to record the presence of zoster-associated pain and abnormal sensations throughout treatment and 6 months' follow-up. They were seen frequently in clinic to verify subjective assessments and for evaluation of rash healing. Safety and tolerability were assessed by adverse event monitoring. RESULTS: Overall, 1191 subjects (63%) were aged > or = 50 years, and 203 (11%) had ophthalmic zoster. Cessation of zoster-associated pain was significantly faster in the younger age group; median times to loss of zoster-associated pain were 23 days and 9 days in the > or = 50 and < 50 years age groups, respectively. Similarly, abnormal sensations resolved significantly more rapidly in the younger subjects; the median duration of abnormal sensations was 31 days in the > or = 50 year olds and 16 days in those aged < 50 years. In cases of ophthalmic zoster, the rate of pain resolution was not different from those with zoster in other dermatomes (median duration of pain 18 vs. 16 days). However, abnormal sensations persisted significantly longer in subjects with ophthalmic zoster than in those with zoster at other sites (47 vs. 22 days). In addition to advancing age, subjects suffering moderate to severe prodromal pain or acute pain during the rash phase were at significantly greater risk of zoster-associated pain and abnormal sensations persisting for longer. Subjects with concomitant neurological disorders were also more likely to develop prolonged abnormal sensations. Valaciclovir treatment was well tolerated, and adverse events were rare and generally mild. CONCLUSION: This study confirmed the prognostic importance of advancing age and the intensity of prodromal or acute pain as risk factors for prolonged zoster-associated pain and persisting abnormal sensations in the affected dermatome. Ophthalmic zoster and pre-existing neurological disorders are also identified as highly significant risk factors for prolonged abnormal sensations in herpes zoster.

Acyclovir↗
PubMed2000

Analyzing the multiple functions of stereotypical behavior for students with autism: implications for assessment and treatment.

We studied behavioral functions associated with stereotypical responses for students with autism. In Study 1, analogue functional analyses (attention, demand, no-attention, and recreation conditions) were conducted for 5 students. Results suggested that stereotypy was multiply determined or occurred across all assessment conditions. For 2 students, stereotypy was associated with positive and negative reinforcement and the absence of environmental stimulation. For 2 other students, stereotypy occurred at high levels across all experimental conditions. For the 5th student, stereotypy was associated with negative reinforcement and the absence of environmental stimulation. In Study 2, the stereotypy of 1 student was further analyzed on a function-by-function basis. Within a concurrent-schedules procedure, alternative responses were taught to the student using functional communication training. The results of Study 2 showed that similar topographies of stereotypy, based on qualitatively different reinforcers, were reduced only when differential reinforcement contingencies for alternative forms of communication were implemented for specific response-reinforcer relations. Our results suggest that the causes of stereotypy for students with autism are complex and that the presumed association between response topography and behavioral function may be less important than previously realized.

Adolescent↗
PubMed2000

Comparative effectiveness of Tiron (4,5-dihydroxy benzene 1,3-disulphonic acid disodium salt) and CaNa2EDTA with time after beryllium poisoning.

The efficacy of two chelating agents (Tiron and calcium disodium EDTA) in the treatment of beryllium induced blood biochemistry and hepatic histopathological alteration was investigated at different duration in female albino rats. Single administration of beryllium nitrate at a dose of 50 mg/kg (im) showed significant decrease in haemoglobin percentage, blood sugar level, protein contents and activity of alkaline phosphatase. On the contrary significant elevation was found in the activity of transaminases (AST and ALT). Tiron was found to be more effective than CaNa2EDTA in reducing the beryllium induced haematological alterations and histopathological lesions in liver. These findings were further confirmed by AAS thus, in which reduced beryllium body burden was seen in liver and blood with Tiron.

1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium ↗
PubMed1998

Treatment of acute herpes zoster: effect of early (< 48 h) versus late (48-72 h) therapy with acyclovir and valaciclovir on prolonged pain.

The efficacy of early versus late treatment with acyclovir and valaciclovir on zoster-associated pain was assessed from two databases (1076 patients) that were compiled from randomized trials. Early treatment was started < 48 h and late treatment was started 48-72 h after the onset of cutaneous herpes zoster. Median times to complete resolution of zoster-associated pain were 28 and 62 days, respectively, for patients (> or = 18 years of age) treated with acyclovir and placebo within 48 h (hazard ratio [HR], 1.68; 95% confidence limit [95% CL], 1.19, 2.38) and 28 and 58 days, respectively, for those treated later (HR, 2.20; 95% CL, 1.03, 4.71). In the valaciclovir versus acyclovir study (in patients > or = 50 years of age), the corresponding figures were 44 and 51 days for patients treated early (HR, 1.28; 95% CL, 1.03, 1.60) and 36 and 48 days for those treated later (HR, 1.40; 95% CL, 1.04, 1.87). Acyclovir significantly shortened the time to complete resolution of zoster-associated pain compared with placebo (and valaciclovir was superior to acyclovir in this regard) even when therapy was delayed up to 72 h after rash onset.

Acute Disease↗
PubMed1998

The identification of risk factors associated with persistent pain following herpes zoster.

Demographic and clinical characteristics of patients with herpes zoster at the time of presentation predict the duration and severity of pain on long-term follow-up. Analyses by Cox's proportional hazard models of six databases from controlled trials of antiviral drugs (total subjects = 2367) identified covariates for zoster-associated pain; all tests for significance were two-sided. Age strongly influenced pain outcome: patients > or = 50 years old were significantly more likely to have prolonged zoster-associated pain compared with those < 30 years old. Patients with prodromal symptoms or moderate or severe pain at presentation were also more likely to experience prolonged zoster-associated pain. Neither time to initiating treatment after rash onset nor sex of patient influenced pain outcome. Advancing age, prodromal symptoms, and acute pain severity at presentation predicted those individuals most at risk of prolonged pain and postherpetic neuralgia. When two or more of these factors were present, the risk of persistent pain was increased.

Adult↗