Gas spectroscopy through multimode self-mixing in a double-metal terahertz quantum cascade laser.

A multimode self-mixing terahertz-frequency gas absorption spectroscopy is demonstrated based on a quantum cascade laser. A double-metal device configuration is used to expand the laser's frequency tuning range, and a precision-micromachined external waveguide module is used to enhance the optical feedback. Methanol spectra are measured using two laser modes at 3.362 and 3.428 THz, simultaneously, with more than eight absorption peaks resolved over a 17 GHz bandwidth, which provide the noise-equivalent absorption sensitivity of 1.20×10-3 cm-1 Hz-1/2 and 2.08×10-3 cm-1 Hz-1/2, respectively. In contrast to all previous self-mixing spectroscopy, our multimode technique expands the sensing bandwidth and duty cycle significantly.

Prognostic value of rapid test for diagnosis of dengue in Nepalese patients during 2010 epidemic.

BACKGROUND: Dengue is an emerging vector borne disease in Nepal and rapid diagnostic test is important for early diagnosis of the disease. OBJECTIVES: The aim of the study was to evaluate the diagnostic accuracy of commonly used rapid immunochromatographic test kit in Nepal during 2010 dengue epidemic and to assess disease burden of dengue. METHODS: A total of 131 acute and nonacute serum samples were collected during recent epidemic of dengue in 2010 from clinically suspected Nepalese patients of different hospitals. Rapid immunochromatographic test kit was used for early diagnosis and enzyme immunosorbent was chosen as a reference assay. RESULTS: The sensitivity and specificity of rapid test was 70% and 76.54% respectively whereas the prevalence of the disease was 38.17%. The odds ratio for males was 1.8 however; the association with the disease was statistically not significant. CONCLUSION: The diagnostic accuracy of rapid immunochromatographic test for dengue diagnosis was low (k=0.46). So, it should be substituted by highly sensitive test device for prompt diagnosis and health personnel should consider appropriate timing of sample collection for better performance of rapid test.

Growth Characteristics of Female Radiation/Clinical Oncologists in South Asia: Assessment of Gender Neutrality and Leadership Position.

AIM: To evaluate the temporal growth pattern of female radiation/clinical oncologists (FRCOs) and, if applicable, predict the gender neutrality in different countries of South Asia. MATERIALS AND METHODS: South Asia is composed of Afghanistan, Bhutan, Maldives, Bangladesh, India, Nepal, Pakistan and Sri Lanka. The growth pattern of FRCOs in the latter five countries having radiation oncology facilities was evaluated from respective national registration data. Based on the average annual differential growth rate, together with the already existing female and male radiation/clinical oncologists (MRCOs), the cumulative numbers of FRCOs and MRCOs were forecasted for the next 10 years. The data regarding FRCOs in a leadership position were also calculated from different sources. RESULTS: The total number of radiation/clinical oncologists in the region was 4074, of which 91.8% were in India, because of its vast population. The overall number of FRCOs and MRCOs stood at 1370 and 2704, with a 1:2 female:male ratio. The average incremental annual growth of FRCOs in India was the highest (12.7 persons/year) and Nepal was the lowest (0.4 persons/year), with no data from Pakistan. If the current growth rate is sustained, Indian gender neutrality will be achieved by 2027-2030. In other countries, gender neutrality is unlikely to be achieved in the near future. With regards to leadership positions, 56-77 radiation oncology departments in India, one each in Bangladesh and Sri Lanka are headed by FRCOs, whereas Nepal and Pakistan have none. CONCLUSIONS: With the current growth rate of FRCOs and MRCOs, India will achieve gender parity within a decade; however, the rest of the countries will not achieve this in the near future. Analysis of radiation/clinical oncologists' registration data with their respective national bodies revealed an encouraging growth in the number of FRCOs as against their male counterparts in the last 5 years, compared with previous decades, especially in Bangladesh, Sri Lanka and India. Sri Lanka show high gender neutrality and adopted a multi-tasking and holistic approach of clinical oncology practices as also seen in Scandinavian countries. Such practice may be helpful to improve gender equality in radiation/clinical oncology practice for the other countries in the South Asian region.

A coeruleo-spinal system in culture.

In combined cultures of dissociated spinal neurons and explants from the region of locus coeruleus, rich catecholamine-containing fiber projections from the explant to the surrounding regions of spinal neurons were demonstrated by fluorescence histochemistry. Electrical stimulation of the explant resulted in slow depolarizing responses in many of the spinal neurons. Cells exhibiting this type of response were also usually depolarized by local application of noradrenaline, whereas other, unresponsive neurons usually were not. The depolarizing responses to electrical stimulation and to noradrenaline were both increased by depolarizing current injection and decreased by hyperpolarizing current. These and other data suggest that the depolarizing responses of the spinal neurons to explant stimulation are mediated by noradrenaline released from axons of locus coeruleus neurons.

Norepinephrine-mediated calcium signaling is altered in vascular smooth muscle of diabetic rat.

We studied the influence of diabetes on norepinephrine (NE)-induced changes in intracellular free Ca2+ levels (receptor-mediated Ca2+ signaling) in single tail artery vascular smooth muscle (VSM) cells. VSM cells from 12-16 week streptozotocin-induced diabetic (SID) rats showed an increase in sensitivity to NE when compared to control VSM cells in that the concentration of NE needed to elicit half maximal response of the initial Ca2+ transient was reduced more than 4-fold though the maximal response attained was apparently reduced. In addition, the slope factor (steepness) of the dose-response relation was lowered 4-fold. Moreover, VSM cells of diabetic animals had a higher incidence of NE-induced Ca2+ oscillatory responses. The shift of the dose-response curve to the left, coupled with a higher incidence of oscillations, indicate that the noradrenergic receptor-mediated Ca2+ signaling pathways in tail artery VSM of diabetic rat may be altered.

Comparison of the effects of methoxamine with those of noradrenaline and phenylephrine on single cerebral cortical neurones.

1 The technique of microelectrophoresis was used to compare the actions of methoxamine, noradrenaline and phenylephrine on single neurones in the somatosensory cerebral cortex of the rat.2 Methoxamine evoked only excitatory responses on cortical neurones. The methoxamine-sensitive cells were also excited by phenylephrine; cells excited by methoxamine could either be excited or depressed by noradrenaline.3 Methoxamine appeared to be less potent than either noradrenaline or phenylephrine in evoking excitatory responses.4 Responses to methoxamine had a slower time course than responses to either noradrenaline or phenylephrine, both the latencies to onset and the recovery times being longer for responses to methoxamine than for responses to noradrenaline or phenylephrine.5 When the absolute mobilities of methoxamine, noradrenaline and phenylephrine were compared using an in vitro method, no significant differences were found between the mobilities of the three ionic species, suggesting that the three drugs have similar transport numbers. Thus the differences in potency between methoxamine and the other two drugs, and the difference between the time courses of responses to methoxamine and the other two drugs, are presumably of biological origin.6 The alpha-adrenoceptor antagonist, phenoxybenzamine, antagonized equally excitatory responses to methoxamine and noradrenaline, and responses to methoxamine and phenylephrine, without affecting responses to acetylcholine.7 When responses to methoxamine and noradrenaline and responses to methoxamine and acetylcholine were summated on the same cells, the net responses were smaller than those expected on the basis of additive effects; the deviation from additivity was greater in the case of the summation of responses to methoxamine and noradrenaline than in the case of summation of responses to methoxamine and acetylcholine. This observation is consistent with the hypothesis that the interaction between methoxamine and noradrenaline follows the model of competitive dualism, whereas the interaction between methoxamine and acetylcholine follows the model of functional synergism.8 The results suggest that methoxamine may act as a partial agonist at excitatory alpha-adrenoceptors on cerebral cortical neurones.

The action of microelectrophoretically applied (3,4-dihydroxy-phenylamino)-2-imidazoline (DPI) on single cortical neurones.

1. The technique of microelectrophoresis was used in order to compare the actions of the imidazoline derivative, (3,4-dihydroxy-phenylamino)-2-imidazoline (DPI), with those of dopamine and phenylephrine on single neurones in the cerebral cortex of the rat anaesthetized with halothane. 2. DPI and phenylephrine were almost exclusively excitatory, whereas dopamine could evoke both excitatory and depressant responses. 3. In the case of excitatory responses, DPI appeared to be more potent than dopamine, and was approximately equipotent with phenylephrine. 4. The dopamine antagonist, haloperidol, could discriminate between excitatory responses to DPI and dopamine: responses to dopamine were abolished, whereas responses to DPI, and to a control agonist, acetylcholine, were unaffected. 5. The alpha-adrenoceptor antagonist, phenoxybenzamine, antagonized equally excitatory responses to DPI and phenylephrine. Responses to acetylcholine were not affected. 6. It is concluded that DPI does not stimulate dopamine receptors on cortical neurones; the excitatory responses of these cells to DPI may be mediated by alpha-adrenoceptors.

Comparison of the responses of single cortical neurones to tyramine and noradrenaline: effects of desipramine.

1 The technique of microelectrophoresis was used in order to compare the actions of tyramine and noradrenaline on single neurones in the cerebral cortex of the rat.2 Tyramine could both excite and depress cortical neurones. Each tyramine-sensitive cell was also sensitive to noradrenaline. There was a high correlation between the directions of responses to tyramine and noradrenaline, most cells excited by tyramine being excited by noradrenaline, and most cells depressed by tyramine being depressed by noradrenaline.3 In the case of both excitatory and depressant responses, tyramine appeared to be less potent than noradrenaline.4 Tyramine evoked ;slower' responses than noradrenaline, both the latencies to onset and the recovery times being longer for responses to tyramine than for responses to noradrenaline.5 When the rates of release of tyramine and noradrenaline from micropipettes were measured in vitro, no significant difference could be observed between the transport numbers of the two drugs. Thus the difference in potency between the two drugs, and the difference in the time courses of responses to the two drugs, are presumably of biological origin.6 Desipramine could discriminate between neuronal responses to tyramine and noradrenaline: responses to tyramine were antagonized, while responses to noradrenaline were either potentiated or unaffected. Responses to DL-homocysteic acid were not affected by desipramine.7 The results are consistent with the hypothesis that tyramine is an indirectly acting sympathomimetic amine in the brain, and desipramine acts by blocking the uptake of both tyramine and noradrenaline into presynaptic noradrenergic nerve terminals.

Long-term monitoring of depolarization-induced exocytosis from adrenal medullary chromaffin cells and pancreatic islet B cells using "perforated patch recording".

(1) Membrane capacitance measurements using perforated patch recording offer the possibility of studying the process of depolarization-secretion coupling (DSC) in single endocrine cells with unprecedented time resolution and stability. (2) Early results with catecholamine-secreting adrenal chromaffin cells and insulin-secreting pancreatic B cells support longstanding ideas that the Ca(2+)-dependent processes underlying DSC are fundamentally similar to those of nerve terminals. (3) Future experiments using these approaches should prove useful in sorting out those effects of humoral substances that have a predominant effect on excitability and Ca2+ entry from those that affect the secretory process itself.

Angiotensin II suppresses Na+ currents in bovine adrenal chromaffin cells.

We investigated the effects of angiotensin II (ANG II) on the voltage-dependent Na+ channel currents (INa) recorded from bovine adrenal medullary chromaffin cells (BCCs) under whole-cell voltage clamp. Angiotensin II reversibly reduced the peak INa in a dose-dependent fashion. Inhibition was observed at a concentration of 1 nM (6.3 +/- 1.4%, mean +/- SEM) and reached a maximum at 1 microM (35 +/- 3.8%), with a half-maximal effect at 11.6 nM. The ANG II-induced inhibition resulted from a reduction in peak conductance (control, 7.2 +/- 0.7 nS; ANG II 4.3 +/- 0.5 nS; p < 0.01). Angiotensin II had no effect on the reversal potential or the decay time of INa. In addition, the V1/2 and k values, two parameters that describe the voltage dependence of INa for both steady-state activation and inactivation, were not affected by ANG II. The response to ANG II (1 microM) had a delay and attained maximum inhibition in 0.9 +/- 0.2 min (n = 10). Recovery from the effect was slow and took 3.5 +/- 0.8 min (n = 10) after the application of ANG II had been terminated. The inhibitory effects of ANG II were effectively blocked by a specific ANG II receptor antagonist. [Sar1, Val5, Ala8]ANG II. The present study demonstrates that ANG II inhibits voltage-dependent INa+ channel currents in BCCs via a specific receptor-coupled mechanism. The prolonged time course of the ANG II response indicates a possible involvement of second messenger(s) mediating this inhibition.

Activation of serotonin1A receptors inhibits midbrain periaqueductal gray neurons of the rat.

The midbrain periaqueductal gray (PAG) is involved in a variety of functions including pain modulation, vocalization, autonomic control, fear and anxiety. This area contains serotonin receptors, particularly 5-HT1A that are known to play a role in the above functions. The goals of this study were to characterize the effects of 8-OH-DPAT, a selective 5-HT1A agonist, on the firing characteristics and membrane properties of PAG neurons. Both in vivo and in vitro preparations were used. The effects of 8-OH-DPAT on baseline activity of 91 neurons were tested in the in vivo preparation. In 50/91 cells, 8-OH-DPAT produced a decrease in the firing rate that ranged between 21 and 98% (mean +/- S.E.M. decrease of 49 +/- 1.9%). This inhibitory effect was dose dependent and could be blocked by spiperone. In 10/91 cells, 8-OH-DPAT produced an increase in the firing rate that ranged between 13 and 290%, with mean increase of 83 +/- 7.4%. The baseline firing rate of the remaining 31 cells was not affected by 8-OH-DPAT. In the PAG slice preparation, the effects of 8-OH-DPAT on synaptic and membrane properties of 17 PAG neurons were tested using whole-cell voltage clamp-recording procedures. In 14 cells, application of 8-OH-DPAT produced hyperpolarization that ranged between 6 and 21 mV, with mean of 8.4 +/- 2.0 mV. This hyperpolarization was associated with a decrease in membrane impedance that ranged between 8 and 45%, with mean decrease of 21.6 +/- 4.5%. The remaining three neurons did not respond to 8-OH-DPAT.(ABSTRACT TRUNCATED AT 250 WORDS)

Cultured rat olfactory neurons are excitable and respond to odors.

Newborn rat nasal tissues containing olfactory epithelium were dissociated and maintained in a monolayer cell culture. Neurons were present, as determined by immunostaining with antibodies to 4 neuron-specific proteins: neuron-specific enolase, microtubule-associated protein 2, tau protein and synaptophysin. Immunostained neurons had a distinctive morphology resembling olfactory neurons. By patch-clamp analysis, these cells were electrically active. Responses of some neurons to physiological concentrations of an odorant mixture identified them as olfactory receptor cells.

Dengue in western Terai region of Nepal.

BACKGROUND: Dengue Fever (DF) is an emerging mosquito-borne disease. It is a nagging public health problem in the low lands of Terai, expanding to new areas of Nepal in recent years. METHODS: A cross-sectional study was conducted to determine anti-Dengue IgM positive rate in Mahendranagar, Dhangadi and Dang between August 2008 and November 2009. Serum samples were collected from 283 patients visiting hospitals with history of fever, headache and suspected DF. The samples were examined by ELISA. RESULTS: The anti-Dengue IgM positivity was found to be 9.8 %. The positive rate was highest in Mahendranagar (13.3 %) followed by Dhangadi (9.8 %) (P<0.05). The Dengue positive cases were higher in female (10.9 %) than males (9.0 %). The positivity was higher in Ethnic group Brahman/Chherti (13.1%) as compared to Janajati (5.6 %). The highest positive cases (10.7 %) were from age group above 50 years. The highest numbers of Dengue positive cases were observed in occupation group of agriculture (18.2 %) (P>0.05). CONCLUSIONS: Dengue has substantial expansion in Western and Far Western Terai region of Nepal which was limited to the middle Terai region in the past and mostly infects older people.

Acute dengue infection in the western terai region of Nepal.

INTRODUCTION: Dengue fever is an emerging mosquito borne disease in Nepal claiming substantial morbidity and mortality. The objective of the study was to find out frequency of acute dengue infection in patients from the hospitals of the western Nepal. METHODS: The study was conducted between August 2007 and July 2008 in patients visiting hospitals of the western terai of Nepal with chief complains of fever. The sero-diagnosis of acute dengue infection was determined by enzyme linked immunosorbent assay among 239 patients visiting Lumbini Zonal Hospital, Butwal; Bheri Zonal Hospital, Nepalgunj; Bardiya District Hospital, Bardiya and Mahakali Zonal Hospital, Mahendranagar. RESULTS: The anti-dengue IgM positivity was 29.3%. There was slight male preponderance with a male to female ratio of 1.2:1. Out of the total positive cases, the highest positive cases (75.7%) were from the age group 15 - 50 years followed by < 15 years old (15.7%). Out of four hospitals, the highest positive cases (54.3%) were in Lumbini Zonal Hospital, Butwal. The age and gender were independent predictors to dengue virus infection. The highest numbers of dengue positive cases were in October (52.6%). The association between dengue disease and the month was statistically significant. CONCLUSIONS: The dengue positivity was estimated in acute patients from hospitals of western Nepal by enzyme immunoassay. Therefore, the serological marker can be used to diagnose acute patients of dengue during outbreaks.

Contributions of mature granule cells to structural plasticity in temporal lobe epilepsy.

During the development of epilepsy in adult animals, newly generated granule cells integrate abnormally into the hippocampus. These new cells migrate to ectopic locations in the hilus, develop aberrant basal dendrites, contribute to mossy fiber sprouting, and exhibit changes in apical dendrite structure and dendritic spine number. Mature granule cells do not appear to exhibit migration defects, basal dendrites, and mossy fiber sprouting, but whether they exhibit apical dendrite abnormalities or spine changes is not known. To address these questions, we examined the apical dendritic structure of bromodeoxyuridine (Brdu)-birthdated, green fluorescent protein (GFP)-expressing granule cells born 2 months before pilocarpine-induced status epilepticus. In contrast to immature granule cells, exposing mature granule cells to status epilepticus did not significantly disrupt the branching structure of their apical dendrites. Mature granule cells did, however, exhibit significant reductions in spine density and spine number relative to age-matched cells from control animals. These data demonstrate that while mature granule cells are resistant to developing the gross structural abnormalities exhibited by younger granule cells, they show similar plastic rearrangement of their dendritic spines.