Inhibition in radiation mediated cellular toxicity by minimizing free radical flux: one of the possible mechanisms of biological protection against lethal ionizing radiation by a sub- fraction of Podophyllum hexandrum

The study has focused on exploring the mechanism of action of Podophyllum hexandrum sub-fraction (G-001M) exhibiting >90% protection in lethally irradiated mice. Currently, G-001M was assessed for antioxidant characteristics by evaluating DPPH, superoxide and hydrogen peroxide radical formation, anti-lipid per oxidation, metal chelation and total flavonoid content. To affirm cytoprotective efficacy of G-001M, plasmid DNA protection, blood WBC counts, marker for lipid peroxidation (MDA) and antioxidant status (GSH) in mice splenocytes and thymocytes were studied. G-001M, having high amount of total phenolic contents (200±10mg, w/w), exhibited dose dependent inhibition in DPPH and superoxide radical formation. Hydrogen peroxide radical scavenging was higher than standards. With pre-treatment of G-001M, plasmid DNA was also maximally restored to supercoiled form. Radiation modulated MDA and GSH values in splenocytes and thymocytes of mice altered significantly after 24 hrs and at later intervals, values were close to the controls. Radiation mediated losses in WBC counts were significantly regained (p<0.001) in G-001M pre-treated irradiated mice. The above findings explicitly conveyed that G-001M has successfully minimized radiation inflicted free radicals generation and their multiplication. This activity of G-001M could be undoubtedly among one of the major modes of action in extending whole body survival in lethally irradiated mice.

Cardio-respiratory reflexes evoked by phenylbiguanide in rats involve vagal afferents which are not sensitive to capsaicin

AIM

Stimulation of pulmonary C fibre receptors by phenylbiguanide (PBG, 5-HT(3) agonist) produces hypotension, bradycardia and tachypnoea or apnoea. However, tachypnoeic or apnoeic responses are not consistent. Therefore, this study was undertaken to delineate the actions of PBG on respiration and compared with those evoked by capsaicin (TRPV1 agonist).

METHODS

Blood pressure, respiratory excursions and ECG were recorded in urethane anaesthetized adult rats. The effect of PBG or capsaicin was evaluated before and after ondansetron (5-HT(3) antagonist), capsazepine (TRPV1 antagonist) or bilateral vagotomy. In addition, their effect on vagal afferent activity was also evaluated.

RESULTS

Bolus injection of PBG produced concentration-dependent (0.1-100 microg kg(-1)) hypotensive and bradycardiac responses, while there was tachypnoea at lower concentrations (0.1-3 microg kg(-1)) and apnoea at higher concentrations (10-100 microg kg(-1)). After vagotomy or after exposure to ondansetron both tachypnoeic and apnoeic responses were abolished along with cardiovascular responses. However, capsazepine (3 mg kg(-1)) did not block the PBG-induced reflex responses. Capsaicin (0.1-10 microg kg(-1)), on the other hand, produced a concentration-dependent apnoea, hypotension and bradycardia but tachypnoea was not observed. Ondansetron failed to block the capsaicin-induced reflex response while bilateral vagotomy abolished bradycardiac and hypotensive responses and attenuated the apnoeic response. In another series, vagal afferent activity and cardio-respiratory changes evoked by PBG were blocked by ondansetron. However, capsaicin failed to activate the PBG-sensitive vagal afferents even though cardio-respiratory alterations were observed.

CONCLUSIONS

The present observations indicate that PBG produced tachypnoea at a lower concentration and apnoea at a higher concentration involving vagal afferents which are different from those excited by capsaicin.

Familial hypoparathyroidism

A family with hereditary (familial) hypoparathyroidism is reported where three of the total four siblings were affected and each presented with different manifestation-one brother with refractory epilepsy since early childhood, another brother with unilateral extrapyramidal features in adult life, and their only sister having recurrent attacks of tingling and numbness due to hypocalcemia since 12 years of age.

Profile of tuberculous meningitis with or without HIV infection and the predicators of adverse outcome

OBJECTIVES

To compare the clinical, radiological and cerebrospinal fluid (CSF) findings, at hospital admission, among adult patients with tuberculous meningitis (TBM) with or without HIV infection and to identify the factors that predict adverse outcome at six months.

METHODS

A total of 82 adult patients with TBM were included (40 HIV-positive and 42 HIV-negative). Several clinical (duration of illness, Glasgow Coma Scale score, presence of high temperature, headache, cranial nerve or sphincter abnormality, seizures and endocrine dysfunction), radiological (presence of hydrocephalus, cerebral infarction and oedema, meningeal enhancement, granuloma) and cerebrospinal fluid parameters (glucose, protein, lactate, lymphocytes, neutrophils and adenosine deaminase values) were recorded along with CD4 count in the peripheral blood. Statistical analysis was performed using the chi-square test. Individual variables were evaluated as prognostic factors for adverse outcome in both groups by calculating the relative risk of association for each.

RESULTS

Temperature more than 38.33 degrees C was more common in the HIV-negative group while seizures, hydrocephalus, cerebral infarction and low CD4 count occurred significantly more commonly in the HIV-positive group. Hydrocephalus had strong association with severe neurological deficit and seizure with death in both the groups.

CONCLUSION

Several clinical and laboratory features of TBM in patients who are HIV-positive are distinctly different from those without HIV infection; some of these have an association with the probability of adverse outcome.

Stochastic resonance-enhanced laser-based particle detector

This paper presents a Laser-based particle detector whose response was enhanced by modulating the Laser diode with a white-noise generator. A Laser sheet was generated to cast a shadow of the object on a 200 dots per inch, 512 x 1 pixels linear sensor array. The Laser diode was modulated with a white-noise generator to achieve stochastic resonance. The white-noise generator essentially amplified the wide-bandwidth (several hundred MHz) noise produced by a reverse-biased zener diode operating in junction-breakdown mode. The gain in the amplifier in the white-noise generator was set such that the Receiver Operating Characteristics plot provided the best discriminability. A monofiber 40 AWG (approximately 80 microm) wire was detected with approximately 88% True Positive rate and approximately 19% False Positive rate in presence of white-noise modulation and with approximately 71% True Positive rate and approximately 15% False Positive rate in absence of white-noise modulation.

Lattice resistance to dislocation motion at the nanoscale

In this Letter, we propose a model that demonstrates the effect of a free surface on the lattice resistance experienced by a moving dislocation in nanodimensional systems. This effect manifests in an enhanced velocity of dislocation due to the proximity of the dislocation line to the surface. To verify this finding, molecular dynamics simulations for an edge dislocation in bcc molybdenum are performed, and the results are found to be in agreement with the numerical implementations of this model. The reduction in this effect at higher stresses and temperatures, as revealed by the simulations, confirms the role of lattice resistance behind the observed change in the dislocation velocity.

Splenic metastasis and bleeding manifestations--an unusual association with gastric malignancy

Splenic metastasis is a rare clinical entity--incidence being 0.6% at autopsy and 1.1% at splenectomy. We report the case of a 30 year old female who presented with purpura and melena and who was later diagnosed to have a mucinous adenocarcinoma of stomach with disseminated intravascular coagulation and splenic metastasis.

Production of activated carbon from coconut shell: optimization using response surface methodology

The production of activated carbon from coconut shell treated with phosphoric acid (H3PO4) was optimized using the response surface methodology (RSM). Fifteen combinations of the three variables namely; impregnation ratio (1, 1.5, and 2); activation time (10, 20, and 30 min); and activation temperature (400, 450, and 500 degrees C) were optimized based on the responses evaluated (yield, bulk density, average pore diameter, small pore diameter, and number of pores in a unit area). Pore diameters were directly measured from scanning electron microscope (SEM) images. Individual second-order response surface models were developed and contour plots were generated for the optimization analysis. The optimum range identified for impregnation ratio was from 1.345 to 2, while for the activation time was from 14.9 to 23.9 min. For the activation temperature it was from 394 to 416 degrees C. The optimum points are 1.725, 19.5 min, and 416 degrees C, respectively. The models were able to predict well the values of the responses when the optimum variable parameters were validated as proven by the generally acceptable values of the residual percentages. Direct characterization of the pores using the SEM was found to be a good technique to actually see the pores and get actual measurements. Additionally, RSM has also proven to be a good tool in optimization analysis to get not only optimum production condition points but ranges, which are crucial for the flexibility of the production process, as well.

DNA replication and the cell cycle

The replication of DNA in the eukaryotic cell cycle is one of the most highly regulated events in cell growth and division. Biochemical studies on the replication of the genome of the small DNA virus simian virus 40 (SV40) have resulted in the identification of a number of DNA replication proteins from human cells. One of these, Replication Protein A (RPA), was phosphorylated in a cell cycle-dependent manner, beginning at the onset of DNA replication. RPA was phosphorylated in vitro by the cell cycle-regulated cdc2 protein kinase. This kinase also stimulated the unwinding of the SV40 origin of DNA replication during initiation of DNA replication in vitro, suggesting a mechanism by which cdc2 kinase may regulate DNA replication. Functional homologues of the DNA replication factors have been identified in extracts from the yeast Saccharomyces cerevisiae, enabling a genetic characterization of the role of these proteins in the replication of cellular DNA. A cellular origin binding protein had not been characterized. To identify proteins that function like T antigen at cellular origins of DNA replication, we examined the structure of a yeast origin of DNA replication in detail. This origin consists of four separate functional elements, one of which is essential. A multiprotein complex that binds to the essential element has been identified and purified. This protein complex binds to all known cellular origins from S. cerevisiae and may function as an origin recognition complex.

Aqueous extract of Rhodiola imbricata rhizome inhibits proliferation of an erythroleukemic cell line K-562 by inducing apoptosis and cell cycle arrest at G2/M phase

Rhodiola imbricata is a medicinal plant having immunostimulating properties. The anti-proliferative effects of Rhodiola aqueous extract (RAE), were studied in human erythroleukemic cell line K-562 using MTT cell proliferation assay. The proliferation of K-562 was significantly decreased after 72h incubation with RAE at 100 and 200microg/ml. However, almost no suppressive effects could be detected in normal human peripheral blood lymphocytes or mouse macrophage cell line RAW-264.7. RAE was also found to induce intracellular reactive oxygen species (ROS) in K-562 cells at 200microg/ml when incubated overnight. The increased ROS generation may cause apoptosis, which was observed in AnnexinV-FITC and propidium iodide (PI) staining of cells treated with RAE for 72h in K-562 cells. Moreover, RAE arrested cell cycle progression in G2/M phase in early and late period of exposure. The anti-cancer activity of RAE was also confirmed by increased NK cell cytotoxicity. These observations suggest that aqueous extract of R. imbricata rhizome has very potent anti-cancer activities, which might be useful in leukemia cancer treatment.

Uncomplicated falciparum malaria complicated by salmonella septicaemia: cause not coincidence

A male patient of 10-year-old presented with fever, headache and vomiting for last few days. He was being treated with antimalarial drugs. On 14th day of illness he again showed rise of temperature. His blood culture showed growth of Salmonella typhi. He was treated with ceftriaxone and responded favourably. Here uncomplicated falciparum malaria developed a secondary infection with salmonella during hospital stay. This uncommon association was noted rather than a mere coincidence, which rarely reported in literature.

Dynamics of lithium ions in bismuthate glasses: Influence of strontium ions

The influence of strontium ions on the relaxation dynamics of lithium ions in bismuthate glasses has been investigated in the frequency range of 10 Hz to 2 MHz. We have observed that the conductivity increases and the activation energy decreases with the increase of SrO content in the glass compositions with fixed Li2O content. We have also observed that the conductivity increases and the activation energy decreases when Sr2+ ions are replaced by Li+ ions, keeping the glass former content fixed. We have shown that the estimated mobile ion concentration is almost independent of temperature and SrO content in the compositions. We have further shown that a fraction of total lithium ions are mobile for all glass compositions. The results have been interpreted on the basis of the modification of the bismuthate network by the addition of SrO, which enhances the mobility of Li ions, without altering the mobile Li+ ion concentration. We have also shown that the conductivity relaxation in these glasses is independent of temperature and composition, and the nonexponential parameter is less than that for the lithium bismuthate glasses without SrO.

A bullet in the maxillary sinus

Maxillary Sinus is an unusual site for lodgment of foreign bodies. We present a rare case of impacted bullel in the right maxillary sinus which entered through the orbital floor which could be removed after using a nasal endoscope through a Caldwell luc approach.

Xylazine, diazepam and midazolam premedicated ketamine anaesthesia in white Leghorn cockerels for typhlectomy

Thee different combinations of ketamine hydrochloride were used to induce general anaesthesia for surgical operations (typhlectomy) in 30 adult, single-comb White Leghorn cockerels. They were randomly divided into three groups, each comprising 10 birds. Birds in Group I received xylazine-ketamine combinations at the dose rate of 2 mg xylazine and 10 mg ketamine per kg i.v., whereas birds of Group II received diazepam (2.5 mg/kg i.v.) and 5 min later ketamine (75 mg/kg i.m.). In the Group III, midazolam (2 mg/kg i.m.) and 5 min later ketamine (50 mg/kg i.v.) was administered. The onset of sedation/anaesthesia was shortest (1.60 +/- 0.27 min) in Group I, followed by Group II (8.40 +/- 0.83 min) and Group III (17.10 +/- 1.71 min). Recovery period was shortest in the Group I (65-75 min) followed by Group II (80-85 min) and Group III (92-105 min). Sedation, muscle relaxation and surgical anaesthesia was optimal and excellent in Group I compared with the other two groups. Torticollis, salivation and dyspnoea were observed in Group III. Short-term limb contractions were present in all birds in Groups II and III, up to 20 min of observation. Recovery from anaesthesia was smooth in all three groups. A Surgical procedure (typhlectomy) was performed on all birds. Hypothermia was observed in Group II, whereas heart and respiratory depression was recorded in Group I. Blood sugar level did not vary significantly in any anaesthetic regime. The reduction of haemoglobin was maximum in Group II compared with Groups I and III. Hypoxaemia and hypercapnaea were elevated in all birds in Groups II and III. Blood electrolytes did not vary significantly from the baseline values among the three groups of birds during the period of observation (120 min). The xylazineketamine combination was found to be the best anaesthesia for surgical intervention in chickens.

Isolated massive thyroid metastasis in lung cancer

Metastasis to the thyroid gland is rare despite its rich vascular supply. Among the pulmonary malignancies metastasising to the thyroid, adenocarcinomas are the commonest. The appearance of metastatic disease in lung carcinoma indicates a poor prognosis and the average survival is two months. We report a 62-year-old woman with squamous cell carcinoma of lung metastatic to the thyroid that produced massive enlargement of the gland. The appearance of the secondary preceded the diagnosis of the primary malignancy by a few months. Ultimately, the patient succumbed to her disease.

Arterial oxygenation changes in valvular heart disease patients with cardiomegaly in different recumbent positions

BACKGROUND AND OBJECTIVE

We studied the effect of different recumbent positions (supine, left and right lateral decubitus), on arterial oxygenation in 42 valvular heart disease patients planned for cardiac surgery. All patients had cardiomegaly (cardiothoracic ratio > or = 0.5) in their chest X-rays. Their left ventricular end-diastolic diameter was also noted from the preoperative echocardiogram.

METHODS

Arterial blood gas analysis was performed in supine, left and right lateral positions after keeping the patient in a given position for 15 min. During this period all patients received 35% oxygen supplementation.

RESULTS

Arterial oxygen tension and haemoglobin saturation were significantly higher in the right lateral position (PaO2 = 120.6 +/- 29.5 mmHg, SaO2 = 98.1 +/- 1.4%) than in supine (PaO2 = 111.0 +/- 30.6 mmHg, SaO2 = 97.6 +/- 2.2%) and left lateral positions (PaO2 = 109.7 +/- 32.0 mmHg, SaO2 = 97.6 +/- 1.7%; mean +/- SD; P 0.05). The change in PaO2 and SaO2 with change of posture from left to right was significantly related to left ventricular end-diastolic diameter (r = 0.50 and r = 0.63, respectively; Pearson correlation). Repeated measures of analysis of variance with left ventricular end-diastolic diameter as a covariate showed a significant change in arterial PaO2 with posture (P = 0.011).

CONCLUSION

Right lateral posture improves arterial oxygenation in the valvular heart disease patient with an enlarged left ventricle. In the preoperative period, these patients may benefit from a right lateral posture when lying in bed.

Panniculitis-like T-cell lymphoma with fatal termination

A 58-year-old male presented with three weeks history of multiple subcutaneous nodules and fever. Histopathological feature of the nodule was characteristic of panniculitis. Three months later, the patient presented with carvical lymphadenopathy and compressive thoracic myelopathy and a diagnosis of diffuse mixed- cell lymphoma was established. Immunohistochemical study of subcutaneous lesions confirmed their T-cell origin. Chemotherapy was started but patient succumbed to his disease.

Interaction of radiation- and bleomycin-induced lesions and influence of glutathione level on the interaction

Radiation-induced exchange aberrations are thought to arise as a consequence of misrejoining of free ends of DNA double strand breaks (dsbs). In quiescent mammalian cells this process of misrejoining is prevalently taken up by the non-homologous end joining (NHEJ) process. In order to investigate the role of glutathione (GSH) in DNA dsb rejoining, the interaction of the lesions induced by bleomycin (Blem) and by radiation was studied since the lesions caused by both have similar and apparent rapid rates of repair. Endogenous GSH was depleted by buthionine sulfoximine (BSO) and chromosome aberrations (CAs) of human lymphocytes were scored from first cycle metaphases. Gamma radiation was administered 2 h after Blem treatment in combined studies. In the case of BSO, the treatment was given 3 h before Blem treatment. The BSO-treated samples showed higher sensitivity to radiation than BSO-untreated ones. Combined treatment of Blem and radiation induced higher frequency of CAs, in particular the exchange aberrations and interstitial deletions. However, such increased frequency of exchange aberrations was reduced drastically and the frequency of terminal deletions was increased significantly when combined treatment was given to BSO-pretreated cells. The consistent level of Ku70 protein in all the treated samples, with undetectable level of Rad51 in the G0-lymphocytes indicates the involvement of NHEJ pathway in misrejoining of DNA dsbs. It may be hypothesized that reduction in the frequency of exchange aberrations as induced by Blem + radiation combined treatment in BSO-treated samples could be because of reduced NHEJ pathway.

Dynamics of lithium ions in calcium bismuthate glasses

Ion transport in Li(2)O-CaO-Bi(2)O(3) glasses has been studied in the frequency range from 10 Hz to 2 MHz and in the temperature range from 293 to 543 K. The variation of the dc conductivity and the activation energy of these glasses with composition have been compared with those of binary lithium bismuthate glasses. It has been observed that the introduction of CaO in small amount does not effect the dc conductivity and the corresponding activation energy, but the larger amount of CaO changes them to some extent. The frequency-dependent conductivity has been studied using both conductivity and modulus formalisms. The values of the nonexponential parameter and frequency exponent are found to differ for the Li(2)O-CaO-Bi(2)O(3) glasses from those for the binary Li(2)O-Bi(2)O(3) glasses. The concentration of mobile Li(+) ions does not change appreciably with the change in the Li(2)O as well as CaO content in the compositions. The increasing amount of CaO in the glass compositions for fixed Li(2)O content points out that CaO dilates the glass network, enhancing the migration of Li(+) ions.