Ultrafast-nonlinear ultraviolet pulse modulation in an AlInGaN polariton waveguide operating up to room temperature.

Ultrafast nonlinear photonics enables a host of applications in advanced on-chip spectroscopy and information processing. These rely on a strong intensity dependent (nonlinear) refractive index capable of modulating optical pulses on sub-picosecond timescales and on length scales suitable for integrated photonics. Currently there is no platform that can provide this for the UV spectral range where broadband spectra generated by nonlinear modulation can pave the way to new on-chip ultrafast (bio-) chemical spectroscopy devices. We demonstrate the giant nonlinearity of UV hybrid light-matter states (exciton-polaritons) up to room temperature in an AlInGaN waveguide. We experimentally measure ultrafast nonlinear spectral broadening of UV pulses in a compact 100 µm long device and deduce a nonlinearity 1000 times that in common UV nonlinear materials and comparable to non-UV polariton devices. Our demonstration promises to underpin a new generation of integrated UV nonlinear light sources for advanced spectroscopy and measurement.

Role of variants rs5030717 and rs5030718 of TLR4 in the risk prediction of nephropathy, hypertension and dyslipidaemia in type 2 diabetes mellitus.

BACKGROUND: Type 2 diabetes mellitus describes a metabolic disorder characterised by prolonged elevated blood glucose that brings a risk of developing microvascular and macrovascular disease. Several factors, such as dysregulation of the Toll-like receptor 4 (TLR-4), are reputed to contribute to the multiple pathophysiological disturbances responsible for impaired glucose homeostasis. We hypothesised that variants rs5030717 and rs5030718 of TLR4 are associated with diabetic nephropathy, hypertension and dyslipidaemia. MATERIAL & METHODS: We recruited 370 diabetics (122 with nephropathy, 119 with hypertension and 129 with dyslipidaemia) and 120 ethnicity matched healthy controls. TLR4 polymorphisms were evaluated using polymerase chain reaction followed by restriction fragment length polymorphism analysis. The genotyping data were compared between cases and controls using chi-square test and logistic regression analysis. RESULTS: Although there was no overall difference in the genotype frequencies of TLR4 rs5030717 in diabetes v controls, the genotype frequencies of diabetic dyslipidaemia cases compared with controls were different (p = 0.001). Overall, the rs5030718 GA and GG genotype frequencies in the entire diabetes cohort were different from those of the controls (p = 0.037), and the frequencies of diabetic nephropathy cases (p = 0.03) and diabetic dyslipidaemia cases were different (p = 0.001) compared with controls. There were no links with diabetic hypertension. CONCLUSION: TLR4 polymorphisms rs5030717 and rs5030718 may be useful in predicting those type 2 diabetics who are at risk of hypertension, nephropathy and/or dyslipidaemia.

Reappraisal of twinning: epidemiology and outcome in the early neonatal period.

INTRODUCTION: The present study aimed to determine the epidemiology, maternal complications and adverse neonatal outcomes associated with twin births at a tertiary care hospital in India. METHODS: A prospective observational study was conducted on all successively born twin pairs (≥ 23 weeks of gestation) and their mothers from January to September 2005. Main outcome measures included maternal medical/obstetric complications, labour characteristics and the morbidities/mortality observed during the early neonatal period. RESULTS: The twinning rate was 1 in 54 deliveries. Around 10% of mothers had a predisposition for twinning in the form of familial tendency or consumption of clomiphene. Anaemia (85%) was the most common maternal complication, followed by gestational hypertension (17%). Nearly one-third of births were delivered via Caesarean section. Prematurity (61%) was the most common neonatal complication followed by early-onset neonatal sepsis (21%). The risk of early neonatal death was 27%. Shorter gestation and low birth weight were significantly associated with adverse neonatal outcome (p < 0.05). Factors such as chorionicity, mode of delivery, birth order, inter-twin delivery time interval, gender and intra-pair birth weight discordance did not affect neonatal morbidity or mortality (p ≥ 0.05). CONCLUSION: The rates of maternal complications and early neonatal morbidities/mortality were quite high in twin gestations. Except for the prematurity and low birth weight, none of the other factors, including inter-twin delivery time interval of more than 15 mins, were found to affect neonatal outcome.

A rabbit eye model for in vivo transformation of progenetic metacercariae of Clinostomum complanatum into ovigerous adult worms.

Clinostomum complanatum is a digenetic trematode that causes yellow grub disease in some fish species and also shows zoonotic potential by sporadically infecting humans. In this study, progenetic metacercariae of C. complanatum were obtained from the fish Trichogaster fasciatus, and were aseptically placed in conjunctival incisions made in the superior and inferior fornices of the eye of rabbits, which served as the experimental hosts. Worms were harvested without necropsy of the host on days 4 and 8 post infection, to observe in vivo transformation of the progenetic metacercariae into ovigerous adult worms. The worms appeared to cause minimal damage to the host although they were tenaciously attached. In vivo maturation was evident by the development of the vitellaria, enlargement of gonads, the presence of a large number of shelled eggs in a distended uterus and ramifications of the intestinal caeca. Obtaining mature ovigerous worms without sacrificing the host clearly gives the rabbit eye model an advantage over those described previously. Due to the relative advantage of the short time required for maturation and the prolific egg production by C. complanatum, it is suggested that this host-parasite system could be used as an excellent model for classroom teaching of trematode biology and to investigate the cues involved in in vivo transformation and host-parasite interactions.

Prevalence of Hypertension Amongst Adult Patients Attending Out Patient Department of Urban Health Training Centre, Department of Community Medicine, Era's Lucknow Medical College and Hospital, Lucknow.

BACKGROUND: Hypertension is the most common disorder which is encountered in outdoor patients. The existing data suggests that there is an increase in the prevalence of pre-hypertension and hypertension in India. The prevalence of hypertension will increase even further, unless broad and effective preventive measures are implemented. The main objective of this study was to find out the prevalence of hypertension amongst the adult outdoor patients of an urban health centre of Lucknow district. MATERIALS AND METHODS: This observational, Out Patients Department based study involved a survey on 306 male and 1203 female respondents who were aged 18 years, who attended the Urban Health Training Centre of the Department of Community Medicine, Era's Lucknow Medical College and Hospital, Lucknow, India. A structured, pretested schedule was used to collect the data with regards to the demographic characteristics and the blood pressure pattern. The Chi- square test and ANOVA were used to analyze the data. RESULTS: The prevalence of hypertension was found to be 44.46%. The proportion of hypertension showed an increasing trend with age. The mean systolic as well as diastolic blood pressure patterns were found to be higher, with an increase in age. CONCLUSION: Hypertension was found to be highly prevalent among the outdoor patients of an urban health centre of Lucknow. An early detection of hypertension can be facilitated by periodically screening people regularly.

Source and origin of nerve fibres immunoreactive for substance P and calcitonin gene-related peptide in the normal and chronically denervated superior cervical sympathetic ganglion of the rat.

Immunohistochemical studies of sympathetic ganglia have indicated that the normal rat superior cervical ganglion contains both SP-IR and CGRP-IR fibres, and CGRP- and SP-immunoreactivity coexist in some fibres. In rat sympathetic ganglia decentralization by preganglionic denervation leads to intraganglionic increase of peptidergic fibres immunoreactive (IR) for substance P (SP) and calcitonin gene-related peptide. We explored the sources of SP- and CGRP-IR fibres in normal and in chronically decentralized rat SCGs. The distribution of immunoreactivities for CGRP and SP was determined in SCGs of normal rats and of rats following preganglionic denervation followed by sensory denervation. Ganglia were studied after short-term (2-5 days) sensory denervation, and long-term (7-16 months) sympathetic denervation followed by short-term (2 days) sensory denervation. To explore for the production of SP and CGRP by intrinsic neurones within the ganglion, normal and chronically decentralized SCGs were examined following pretreatment by local in vivo application of colchicine. Normal and chronically decentralized ganglia were also injected with fluorescent tracer Fluorogold for retrograde tracing of extrinsic fibres back to their neurones of origin. The observations suggest that in normal SCG in the rat the SP-IR and CGRP-IR nerve fibres are derived via direct links from vagus and glossopharyngeal nerves and the cervical plexus, or from nerve fibres running along the cervical sympathetic trunk, and the external carotid and the internal carotid nerves. Sensory nerve inputs to the rat SCG following decentralization may contribute to the low levels of ganglionic activation observable in the autonomic failure of multiple system atrophy in man.

Training workshops in problem-based learning: changing faculty attitudes and perceptions in a Pakistani medical college.

BACKGROUND: Problem-based learning (PBL) has over the years become a learning strategy established for teaching students in medicine. In order to use PBL as a teaching tool, faculty must be familiar with PBL and comfortable with the role transition from 'teacher' to 'facilitator'. This transition is critical for the success of PBL. This article describes the faculty development process undertaken in Pakistan at the onset of introduction of PBL in the curriculum. METHODS: At the Foundation University Medical College (FUMC), we initiated a faculty development program in PBL. The program consisted of two-day, hands-on facilitator training workshops conducted five times over the year and led by in-house faculty. A total of 180 faculty members completed these workshops. The workshops consisted of interactive sessions on the philosophy of PBL, small group dynamics, the role of the facilitator, an introduction to case design, wrap-up PBL sessions and assessment in PBL. Participants were provided with pre-workshop reading material in the form of 'PBL Handbooks', which contained details of the PBL process and specific responsibilities of the facilitator. Participants were also given a chance to experience the role of the facilitator by facilitating the faculty-learner group through a PBL session and receiving feedback. A retrospective pre-post survey was conducted to gauge changes in participants' perceptions of PBL. RESULTS: The faculty reported a significant increase in their regard for PBL as an instructional paradigm (p=<0.001). They also generally became more interested in empowering students with self-directed learning using PBL as a teaching tool and showed a greater desire to be facilitators (p=<0.001). CONCLUSION: This evaluation reveals that facilitator training workshops can help not just to improve the facilitation skills of participants but also to stimulate interest amongst faculty to use PBL in the curriculum. Such workshops can be run in Pakistan at minimal cost: the only cost we incurred was for photocopying the reading material. How much difficulty the faculty will actually have serving as facilitator in the PBL process will only become evident when they lead PBL groups over the coming year.

Prediction of stability factors at the domain interface of human gammaB crystallin maintaining the transparency of the eye lens.

OBJECTIVE: betagamma-crystallins are among the most long lived globular proteins known today. Interaction of the two domains through a hydrophobic interface is one of the major contributors to the stability of these crystallins. Changes in these interactions are either due to the amino acid substitutions or the changes in the orientations of the same amino acids leading to cataract formation. We have carded out a detailed analysis to observe the stabilizing effects of hydrophobic core residues at the domain interface of the predicted human gammaB-crystallin structure. METHODS: Human gammaB-crystallin model was built by Homology Modeling hsing MODELLER4 based on the crystal structure coordinates of bovine gammaB-crystallin. In lens gammaB-crystallin, there are six non polar residues, three each in the two domains which form a hydrophobic core at the domain interface. We performed mutational studies at position 56 and analyzed the changes in the protein structure. Three mutants (Phe-->Trp. Phe-->Ala, Phe-->Asp) were constructed and analyzed for hydrogen bonding, ion pairs and accessibility by WHATIF web server. RESULTS: Being the largest amino acid among the six residues taking part in the hydrophobic interactions at the domain interface, Phe was predicted to be responsible for the greatest contribution to the stability at this region. Phe-->Ala mutant showed the largest structural changes in the vicinity of the mutated residue. CONCLUSION: The results obtained clearly emphasize the importance of hydrophobic interactions to the stability of crystallins. Mutations at the domain interphase could decrease the interactions between these domains thus causing destability.

Cancer patterns in Karachi division (1998-1999).

OBJECTIVE: A minimal cancer incidence data for Karachi, the largest city of Pakistan, is being presented here, for the years 1998-1999. The city has a population of 9,802,134; males 5,261,712 (52.6%) and females 4,540,422 (47.4%); census 1998. METHODOLOGY: A predominantly mixed (passive and active) registration system has evolved in Karachi, the data sources being the hospitals within the Karachi Division. The reported/retrieved cancer data sets at the Karachi Cancer Registry are checked, coded, computerised in an analytical format and analysed. RESULTS: The incident cancer cases registered in Karachi, during the 2-year period, 1st January 1998 to 31st December 1999 were analysed. The age-standardised incidence rate (ASR) of cancer, all sites was 132.4/100,000 for the males. Cancer of the lung 10.8%; ASR 17.3 was the most frequently recorded malignancy, followed by oral cavity 10.5%; ASR 13.2 and larynx 5.0%; ASR 7.4. The age-standardised incidence rate (ASR) of cancer, all sites was 133.0/100,000 in the females. Cancer of the breast, 32.0%; ASR 40.7 was the most frequently recorded malignancy, followed by oral cavity 8.1%; ASR 11.7 and gall bladder 3.6%; ASR 5.5. CONCLUSION: The present data has been calculated with an estimated 15-20% probable under ascertainment. Tobacco-associated cancers in Karachi were responsible for 38.3% of the tumours diagnosed amongst the males. Two principal cancers, breast and oral cavity were responsible for 40.1% of the cancers in females. A rare finding was the high incidence of gall bladder cancer in the females. At present it is difficult to determine whether this indicates a genuine high risk or a selection bias. A continuous process of cancer registration to study the trends in the incidence and an adequate cancer control program are possible and essential for Pakistan and can be based on the pattern being practiced in Karachi.

Correlation of the density of yeast Malassezia with the clinical severity of seborrhoeic dermatitis.

OBJECTIVE: To correlate the density of the yeast Malassezia with the clinical seventy of seborrhoeic dermatitis. METHOD: Fifty patients and twenty control subjects were selected for the study. The patients were evaluated both clinically for the severity of seborrhoeic dermatitis and microscopically for the presence of the yeast Malassezia. RESULTS: Out of 50 patients Malassezia was present in 41 patients (82%). On microscopic evaluation it was found that patients with mild seborrhoeic dermatiis had a density of 2+ (more than 5 but less than 10 yeast cells per high power field (hpf). Patients with moderate seborrhoeic dermatitis had a density of 3+ (more than 10 but less than 20 yeast cells per hpf) and patients with severe seborrhoeic dermatitis had a density of 4+ (more than 20 yeast cells per hpf). Of the 20 normal subjects only 8 (40%) had Malassezia and they had a density of 1+ (5 or fewer yeast cells per hpf). The results show a strong correlation of the yeast Malassezia to the severity of seborrhoeic dermatitis (p value < 0.05). CONCLUSION: Malassezia increases in proportion with the severity of seborrhoeic dermatitis; an antifungal agent should therefore be used in the treatment of seborrhoeic dermatitis.

Homology modeling of nematode Caenorhabditis elegans CED3 protein-inhibitor complex.

CED3 protein, the product of a gene necessary for programmed cell death in the nematode Caenorhabditis elegans, is related to a highly specific cysteine protease family i.e., caspases. A tertiary-structural model has been constructed of a complex of the CED3 protein with tetrapeptide-aldehyde inhibitor, Ac-DEVD-CHO. The conformation of CED3 protein active site and the general binding features of inhibitor residues are similar to those observed in other caspases. The loop segment (Phe380-Pro387) binds with the P4 Asp in a different fashion compared to caspase-3. The comparative modeling of active sites from caspase-3 and CED3 protein indicated that although these enzymes require Asp at the position P4, variation could occur in the binding of this residue at the S4 subsite. This model allowed the definition of substrate specificity of CED3 protein from the structural standpoint and provided insight in designing of mutants for structure-function studies of this classical caspase homologue.

A potential role for protein kinase C-epsilon in regulating megakaryocytic lineage commitment.

Multiple studies have shown that intracellular signal transduction by the protein kinase C (PKC) family participates in the initiation of megakaryocyte differentiation. In this study, multiple approaches addressed the functional contributions by specific PKC isozymes to megakaryocytic lineage commitment of two independent cell lines, K562 and human erythroleukemia (HEL). Pharmacologic profiles of induction and inhibition of megakaryocytic differentiation in both cell lines suggested a role for the calcium-independent novel PKCs, in particular PKC-epsilon. In transfection studies, the isolated variable domain of PKC-epsilon selectively blocked exogenous activation of the megakaryocyte-specific alpha IIb promoter. Constitutively active mutants of PKC-epsilon, but not of other PKC isozymes, cooperated with the transcription factor GATA-1 in the activation of the alpha IIb promoter. The functional cooperation between GATA-1 and PKC-epsilon displayed dependence on cellular milieu, as well as on the promoter context of GATA binding sites. In aggregate, the data suggest that PKC-epsilon specifically participates in megakaryocytic lineage commitment through functional cooperation with GATA-1 in the activation of megakaryocytic promoters.

Intraoral chilling versus oral sumatriptan for acute migraine.

Migraine pathophysiology is associated with a dural inflammation. Recent evidence suggests that the primary inflammation occurs in a maxillary nerve segment, accessible intraorally. Local tenderness, related to symptom laterality, has been palpated consistently in asymptomatic migraine patients, and significant migraine relief has been obtained from chilling confined to this area. Thirty-five symptomatic episodic migraine patients were enrolled in this study, comparing 40 minutes of bilateral intraoral chilling, 50 mg of oral sumatriptan, and 40 minutes of sham (tongue) chilling. Hollow metal tubes chilled by circulating ice water were held in the maxillary molar periapical areas by the patient. Pain and nausea were recorded at baseline and 1, 2, 4, and 24 hours after start of treatment, using a numeric symptom-relief scale. Significant mean headache relief was obtained by maxillary chilling and sumatriptan at all four time intervals, with poor relief obtained by placebo. Maxillary chilling was more effective than sumatriptan at all four time intervals. Significant nausea relief was obtained by maxillary chilling and sumatriptan at posttreatment and 2 and 4 hours later. At 24 hours, some headache and nausea recurrence was noted with sumatriptan. The repeated-measures analysis of variance indicated that both treatments, drug (P = 0.024) and maxillary chilling (P = 0.001), reduced the headache, as compared with the control group. Tenderness suggests local inflammation associated with vasodilatation and edema. Because chilling can resolve local edema, these findings raise the possibility that an intraoral inflammation may be a factor in migraine etiology.

Low-resolution molecular structures of isolated functional units from arthropodan and molluscan hemocyanin.

Synchrotron x-ray scattering measurements were performed on dilute solutions of the purified hemocyanin subunit (Bsin1) from scorpion (Buthus sindicus) and the N-terminal functional unit (Rta) from a marine snail (Rapana thomasiana). The model-independent approach based on spherical harmonics was applied to calculate the molecular envelopes directly from the scattering profiles. Their molecular shapes in solution could be restored at 2-nm resolution. We show that these units represent stable, globular building blocks of the two hemocyanin families and emphasize their conformational differences on a subunit level. Because no crystallographic or electron microscopy data are available for isolated functional units, this study provides for the first time structural information for isolated, monomeric functional subunits from both hemocyanin families. This has been made possible through the use of low protein concentrations (< or = 1 mg/ml). The observed structural differences may offer advantages in building very different overall molecular architectures of hemocyanin by the two phyla.

Sea snake Hydrophis cyanocinctus venom. II. Histopathological changes, induced by a myotoxic phospholipase A2 (PLA2-H1).

A toxic phospholipase A2 (PLA2-H1), isolated from the venom of the sea snake Hydrophis cyanocinctus, was tested for its ability to induce myonecrosis and histopathological changes in albino rats and mice. Induction of myonecrosis was demonstrated by their ability to release creatine kinase (CK) from damaged muscle fibers and direct histopathological examination of the injected muscles (i.m.). PLA2-H1 exhibits intense myonecrosis characterized by the changes including, necrosis and edematous appearance with cellular infiltrate, vacuolation and degenerated muscle cells with delta lesions and heavy edema in between the cells. No myoglobinuria was noted in any group of animals. The purified PLA2-H1 was also administered intraperitoneally into the experimental animals and tissue samples were taken at several time intervals. Light microscopic examination of the kidney sections revealed severe damage, evident by focal tubular necrosis, complete disquamation of epithelial lining and epithelial degeneration of tubules in all test animals. Light micrographs of liver sections after 24 h of injection shows fatty infiltration in parenchyma and squashed hepatocytes, while after 48 h, fatty vacuolation of parenchyma in a generalized pattern was observed. Furthermore, sections of the lungs of the same group of animals (48 h) show dilated bronchia and marked infiltration of inflammatory cells within alveoli. Our results suggest that the purified PLA2-H1 induced moderate myotoxicity in muscles and mild histopathological changes in other vital organs without myoglobinuria.

Stimulant-induced exocytosis from neuronal somata, dendrites, and newly formed synaptic nerve terminals in chronically decentralized sympathetic ganglia of the rat.

Loss of preganglionic neurones underlies the autonomic failure of human multiple system atrophy. In rat sympathetic ganglia decentralization leads to new synapse formation. We explored whether these synapses are functional, and whether chronically decentralized neurones respond normally to activation, in terms of exocytosis. Potassium depolarization and cholinergic agonists were applied to freshly excised rat superior cervical sympathetic ganglia, preganglionically denervated with prevented reinnervation 5 months earlier. Ganglia were incubated and stimulated in the presence of tannic acid, which stabilizes released vesicle cores for subsequent electron microscopy. In denervated ganglia exocytosis was observed from newly formed synaptic nerve terminals, and from nonsynaptic surfaces of neurone somata and dendrites. The results demonstrated that the new intraganglionic synapses, which are mostly catecholaminergic, can function and that chronically decentralized sympathetic neurones remain capable of stimulant-induced exocytosis from somata and dendrites. The maximal release upon potassium depolarization did not differ significantly between denervated and contralateral ganglia. Relative to this, the exocytotic responses of decentralized somata and dendrites to nicotine resembled those of contralateral ganglia. Responses to muscarine were significantly less in denervated than in contralateral ganglia, indicating inhibition in dendrites. Responses to carbachol suggested interactions between nicotinic and excitatory muscarinic effects. Nerve terminals in denervated ganglia showed high basal release. Their responses to muscarine and carbachol resembled those of the decentralized neurones, from which most may originate. Their response to nicotine evidenced inhibition. Their actions, coupled with nonsynaptic effects of soma-dendritic exocytosis, might modulate responses of the decentralized neurone population to other surviving inputs. This modulation could be influential in disease-induced decentralization in man.

Predicted three-dimensional structural models of venom serine protease inhibitors and their interactions with trypsin and chymotrypsin.

Three homology models of trypsin and chymotrypsin inhibitor polypeptides from snake venom of Naja naja naja and Leaf-nosed viper in the unbound state and in complex with trypsin and chymotrypsin were built based on homology to bovine pancreatic trypsin inhibitor (BPTI). These venom inhibitors belong to the Kunitz-type inhibitor family, which is characterized by a distinct tertiary fold with three-conserved disulfide bonds. The general folding pattern in these trypsin and chymotrypsin inhibitor homology models is conserved when compared to BPTI. The respective orientations of the inhibitors bound to trypsin/chymotrypsin are similar to that of BPTI bound to bovine trypsin/chymotrypsin. The principal binding loop structure of the inhibitors fills the active site of enzymes in a substrate-like conformation and forms a series of independent main-chain and side-chain interactions with enzymes. In order to provide the possible fingerprints for molecular recognition at the enzyme-inhibitor interface, a detailed theoretical analysis of the interactions between the principal binding loop of these inhibitors and active site of trypsin/chymotrypsin is performed based on available crystal structural, site-directed mutagenetic, kinetic, and sequence analysis studies. Despite the variations present at different positions of the principal binding loop of trypsin and chymotrypsin inhibitor models from Leaf-nosed viper and cobra Naja naja naja, respectively (designated as LnvTI and NCI), there are favorable subsite binding interactions which are expected to exhibit equally potent inhibitory activity as BPTI. On the contrary, significant mutations at several secondary specificity positions in the Naja naja naja trypsin inhibitor (designated as NTI) are likely to affect different inhibitor-enzyme-subsites interactions. This may explain the observed increased inhibitory activity of this polypeptide on a structural basis.

Molecular modeling of human procathepsin E: analysis of salt-bridge interactions between propeptide and enzyme segment.

A three-dimensional structural model of human cathepsin E zymogen (e. g., procathepsin E) has been constructed based upon the crystal structures of porcine pepsinogen. The overall protein folding features of the model are similar to those observed in the template structures. The propeptide packs into the active-site cleft with a similar secondary structural pattern and is associated with enzyme segment by salt-bridges, hydrogen bondings, and hydrophobic interactions. As judged from the model, the salt bridges present between the propeptide and enzyme segment show remarkable variations compared to porcine pepsinogen and human progastricin structures. Mapping of these interactions revealed that human procathepsin E might engage a different structural motif (alpha-helix;12P-19P) for protecting/blocking of catalytic site compared to pepsinogen and progastricin.