On the near UV photophysics of a phenylalanine residue: conformation-dependent ππ* state deactivation revealed by laser spectroscopy of isolated neutral dipeptides

The primary step of the near UV photophysics is investigated in pump–probe R2PI ns experiments carried out on specific conformers of model peptide chains.

TGF-β1 induces EMT reprogramming of porcine bladder urothelial cells into collagen producing fibroblasts-like cells in a Smad2/Smad3-dependent manner

Activation of fibroblasts and their differentiation into myofibroblasts, excessive collagen production and fibrosis occurs in a number of bladder diseases. Similarly, conversion of epithelial cells into mesenchymal cells (EMT) has been shown to increase fibroblasts like cells. TGF-β1 can induce the EMT and the role of TGF-β1-induced EMT during bladder injury leading to fibrosis and possible organ failure is gaining increasing interest. Here we show that EMT and fibrosis in porcine bladder urothelial (UC) cells are Smad dependent. Fresh normal porcine bladder urothelial cells were grown in culture with or without TGF-β1 and EMT markers were assessed. TGF-β1 treatment induced changes in cellular morphology as depicted by a significant decrease in the expression of E-cadherin and corresponding increase in N-cadherin and α-SMA. We knocked down Smad2 and Smad3 by Smad specific siRNA. Downregulation of E-cadherin expression by TGF-β1 was Smad3-dependent, whereas N-cadherin and α-SMA were dependent on both Smad2 and Smad3. Connective tissue growth factor (CTGF/CCN2), matrix metalloproteinase-2 and -9 (MMP-2, MMP-9) has been shown to play important roles in the pathogenesis of fibrosis. Induction of these genes by TGF-β1 was found to be time dependent. Upregulation of CTGF/CCN2 by TGF-β1 was Smad3 dependent; whereas MMP-2 was Smad2 dependent. Smad2 and Smad3 both participated in MMP-9 expression. TGF-β1 reprogrammed mesenchymal fibroblast like cells robustly expressed collagen I and III and these was inhibited by SB-431542, a TGF-β receptor inhibitor. Our results indicate that EMT of porcine bladder UC cells is TGF-β1 dependent and is mediated through Smad2 and Smad3. TGF-β1 may be an important factor in the development of bladder fibrosis via an EMT mechanism. This identifies a potential amenable therapeutic target.

Electrochemical measurement and speciation of inorganic arsenic in groundwater of Bangladesh

The presence of arsenic in groundwater above the maximum permissible limit of 50 mug l(-1) has threatened the health of more than 50 million people in Bangladesh and neighboring India. We report here the development of an inexpensive anodic stripping voltammetric (ASV) technique for routine measurement and speciation of arsenic in groundwater. The measurements are validated by more expensive atomic absorption, atomic emission and other techniques. To understand the present situation in Bangladesh, we measured As(III) in 960 water samples collected from 18 districts. A random distribution of 238 samples was used to measure both As(III) and As(V). The results from the present study indicate that most toxic form of inorganic arsenic, As(III), has the broad range of 30-98%. It shows 60% of the samples have 10 mug l(-1) and 44% of the samples have 50 mug l(-1) or more As(III). The fractional distribution pattern shows significant skew towards high percent occurrence which may indicate a progressive reduction process with a single source or a single mechanism for the formation of As(III). For direct consumption, this is possibly one of the most toxic groundwater known today. Speciation distribution at groundwater pH value shows H(3)AsO(3) is the predominant species including H(2)AsO(4)(-) and H(2)AsO(4)(2-) whose distribution is significantly pH dependent. This is also supported by E(h)-pH measurements. The depth distribution for Kushtia shows most of the As(III) is located within 100-200 ft deep aquifers. Similar fractional distribution of As(III) is found in deeper aquifers and may indicate contamination by leakage from upper aquifer. This study clearly demonstrates the aquifer environment is reductive and conducive to the formation of As(III) species.

Antihyperglycemic effect of Trigonella foenum-graecum (fenugreek) seed extract in alloxan-induced diabetic rats and its use in diabetes mellitus: a brief qualitative phytochemical and acute toxicity test on the extract

The effects of ethanol extract of Trigonella foenum-graecum (Fenugreek) seeds on the blood glucose levels in alloxan-induced diabetic rats at different doses (2 g/kg, 1 g/kg, 0.5 g/kg and 0.1 g/kg) were studied. The hypoglycemic effect of extract was compared with that of the standard antidiabetic drug (glimepiride, 4 mg/kg) single dose. The extract showed significant activity against the diabetic state induced by alloxan but the intensity of hypoglycemic effect varied from dose to dose. The most effective dose recognized was 1 g/kg but that is still lower than the standard antidiabetic drug. No acute toxicity was observed for ethanol extract of T. foenum-graecum seed when it was administered orally at high dose level (3 g/kg body weight), which is higher than effective antihyperglycemic dose, and closely observed for 24 hrs for any mortality and next 10 days for any delayed toxic effects on gross behavioral activities. Phytochemical group tests were also accomplished and presence of alkaloids, steroids and carbohydrates were recognized in the extract.

Hearing status of elderly people: study in a tertiary level hospital

A study was carried out from April 2003 to March 2004 at the Department of Otolaryngology and Head-Neck Surgery, BSMMU, with the aim to evaluate the prevalence of hearing loss and to find out the pattern and extent of hearing loss among the elderly people. The study included 100 people aged over 50 years. Out of 100 cases 59% were found with normal hearing and 41% had variable degree of hearing impairment. The highest prevalence of hearing impairment was found 100% in 9th decade with gradually decreasing tendency and lowest was 29.50% in 6th decade. Most of the cases were found to be bilateral (65.85%). Majority (65.85%) of the hearing impaired people had sensorineural type of loss with a significant number (21.95%) of conductive loss. Irrespective of type of impairment. Most of the people (73%) had no complaint of ear problem during presentation. Only 27% had some sorts of otological symptoms like hearing loss, tinnitus and vertigo and among them about 96.29% complained of hearing loss. About 44.44% of the hearing impaired person of 6th decade, showed mild hearing loss. In the 7th decade maximum (50%) had moderate to severe hearing loss. About 31% of persons of 8th decade and 50% of 9th decade had severe degree of hearing loss.

Intranasal meningoencephalocoele-a rare childhood condition

Congenital or acquired intranasal meningocoele or meningoencephalocoele is a rare condition ever reported in world literature. We report a case of intranasal meningoencephalocoele in which a 10 month old male child presented with left sided progressive nasal obstruction, nasal mass and reluctant to feed. On examination slight broadening of the bridge of the nose with obliteration of left nasomaxillary fold, mucoid discharge and a pinkish, polypoidal, non tender, non pulsatile mass with prominent blood vessels on the surface occupying almost 3/4(th) of the nasal cavity was observed. On probing it appeared to be attached to roof of left nasal cavity. Computed tomography revealed a hypodense area in the nasal cavity but there was no bony defect in the skull base. Peroperatively on aspiration of nasal cystic mass revealed free flow of clear fluid which was biochemically CSF. A one stage, Lynch Howarth approach, correctional procedure was performed. We present here a discussion of findings and surgical treatment. Early diagnosis and referral are of paramount importance, because failure to identify this leads to fatal outcome if surgery performed.

Outcome of management of differentiated thyroid carcinoma

A prospective study was done on 93 cases of differentiated thyroid carcinoma to find out the outcome of management according to the protocol followed in the Department of ENT-Head and Neck Surgery of Bangabandhu Sheikh Mujib Medical University Hospital. Here Papillary carcinoma is more common (76.35%) than follicular carcinoma. Papillary carcinoma affected in the younger patients more commonly than the follicular carcinoma with a mean age of 34.37years (SD=12.81) for papillary carcinoma and 44.93 years (SD=16.01) for follicular carcinoma; but age as a risk factor showed no significant difference between two histological types (p>0.05). Female was the predominant sex with a ratio of 3.04:1. In this series majority of patients were categorized as high risk group (75.27%). There is strong association between histological type & risk group (P<0.05). High risk group is more common in follicular carcinoma (95.45% Vs 69.01%). There was a significant differences between the two histological types for extrathyroidal extention and distant metastasis as risk factors (p<0.01 and p<0.001); but tumour size and lymphatic metastasis showed no significant difference (p>0.05). All low risk patients were treated by hemithyriodectomy followed by life long thyroxine. All high risk cases were treated with total thyroidectomy with (35.71%) or without (62.86%) different types of neck dissection (according to the degree of lymph node involvement) followed by radioiodine ablasion and lifelong thyroxine therapy routinely. Overall rate of complication of thyroid surgery was 23.08%. The commoner complications were vocal cord palsy (5.5%), hypoparathyroidism (5.5%) and haemorrhage (4.4%). Less common complications were laryngeal oedema (2.2%), wound infection (2.2%), tracheal injury (1.1%) and death (2.2%). Many cases lost to follow up. Sixty seven cases (73.64%) responded well for follow-up. Mean duration of follow up was 3.40 years (SD=1.41). There was recurrence in thyroid remnant in 9.09% of hemithyroidectomy cases and were treated by completion thyroidectomy followed by radioiodine ablasion. Regional lymphatic metastasis was seen in six cases and was treated by different types of neck dissection. Recurrence at distal site was seen in 4 cases (18.18% of follicular carcinoma). These were treated by radioiodine ablation; two of them died during the period of follow-up.

Genital fistula--our experience

Genital fistulas cause immense physical and psychosocial problem in women's life. The present study was conducted to note the varieties of genital fistula as well as their causative factors and the results of the operative corrections. Altogether 42 patients with different varieties of genital fistula were enrolled in the study. The causative factors of the genital fistulas, specially, that of vesicovaginal fistulas were thoroughly enquired. After confirming the diagnosis, the operative corrections were undertaken. Among the varieties of genital fistula, 76.19% were vesicovaginal fistula, 11.90% were rectovaginal fistula and 4.76%, 4.76% and 2.38% cases of ureterovaginal, urethrovaginal and vesicocervical fistulas respectively. The primipara women were the major sufferers of genital fistulas due to obstetric grounds. Regarding aetiologies of vesicovaginal fistulas, 71.87% patients had obstetric reasons, after prolonged labour, instrumental delivery and after caesarean section due to obstructed labour. Abdominal hysterectomy (44.44%) topped the list of the gynaecological causes of vesicovaginal fistulas. The cases of ureterovaginal fistulas were after abdominal hysterectomy. One case of urethrovaginal fistula was due to some chemical application for correction of genital prolapses. The rectovaginal fistulas were mostly due to obstetric reasons. The success rate after the first attempt of repair of vesicovaginal fistula was 82.75% and overall failure was 10.34%. The other varieties of fistulas were repaired with 100% success rate. The incidence of genital fistulas can be reduced by vigilant obstetric care and meticulous surgery.

Head and neck squamous cell carcinoma (HNSCC) 5 year study at BSMMU

Head and Neck Squamous Cell Carcinoma (HNSCC) are generally similar in their clinical features, epidemiology and etiology although their natural and clinical history and treatment differ. Despite lot of improvement in diagnostic and management technique, there is little improvement in survival rate over the last few decades. This study was carried-out in a multidisciplinary tertiary level hospital (BSMMU), with a country-wide catchment area to see the burden of HNSCC existing in our country and their clinical pattern. The overall incidence rate of HNSCC in this study was (0.15%) i.e. 150 person in 1,00,000 population. Male incidence (0.19%) was higher than female (0.12%). This study revealed that carcinoma of the larynx (25.22%) and pyriform fossae (20.57%) were the main culprit, whereas buccal carcinoma was the main component (37.70%) in the female series. Highest incidence was found in the 6th decade in both sexes. As the treatment of HNSCC may be time consuming, requires multidisciplinary approach, demands lot of clinical, social and financial consideration, therefore, the best treatment can be offered through a combined board consisting of Surgical, Radiation, Medical oncologists, Histopathologist and Speech therapist as required.

Management of thyroid carcinoma-an experience in Bangladesh

All patients (n=154) of thyroid malignancy admitted in the Otoluryngology Department of Bangabandhu Sheikh Mujib Medical University (former IPGMR) between 1986 and 2000 were retrospectively analyzed to find out the extent and result of surgery used for thyroid carcinoma. The other objectives were to find out the incidence of differentiated thyroid carcinoma among the thyroid malignancy and also to find out the age, sex and clinical presentation of papillary and follicular carcinoma. Among all the thyroid malignancy (n-154), Differentiated Thyroid Carcinoma (DTC) was seen in 130 (84.41%) cases, where as papillary carcinoma occurred in 98(63.64%), and follicular carcinoma in 32(20.77%)cases. On the basis of risk factors, the DTC were designated as low and high risk. The year-wise incidence of DTC revealed increasing trend from 1986 (3 cases) to 2000 (23 cases).Among the 98 papillary thyroid carcinoma highest number of cases (35.71%) were seen in 31-40 year age group. The male to female ratio was 1: 1.64. In follicular carcinoma, highest number (35.25%) of cases were also seen in 31-40 year age group. The male to female ratio was 1:1.66. The commonest presentation in papillary carcinoma was thyroid swelling (96.93%). The other presentations were occult thyroid (3.06%), Cervical lymph node metastasis (38.77%) and distant metastasis (2.04%). In Follicular carcinoma, the presentations were thyroid swelling (100%), Cervical lymph node metastasis (6.25%) and Distant metastasis (21.87%).In this series, low risk DTC were treated by Lobectomy & Isthmusectomy plus Thyroxin. In low risk group the rate of recurrence was 6.89% and the mortality was nil in five years follow-up. Except two inoperable cases, all high risk patients were managed by Total thyroidectomy (with or without neck dissection, plus removal of metastatic lesion when required) with Radioiodine ablation plus Thyroxin. . The rate of recurrence was 7.81% and mortality was 1.56% in high risk group in similar period of time.Vocal cord palsy were noted in 5 (3.84%) unilateral, and inane (0.76%) bilateral cases. Hypoparathyroidism was found in 4.61%.

Antioxidants in detoxification of arsenic-induced oxidative injury in rabbits: preliminary results

To assess the oxidative injuries caused by arsenic toxicity in rabbits and evaluate the detoxifying effects of exogenous antioxidants, we administered arsenic trioxide (3-5 mg/kg/day) in rabbits through a feeding tube for seven days. These rabbits were then treated with a recipe of vitamins, zinc, selenium (VZS) or a plant polyphenol or a placebo for the next seven days. Blood samples were collected from ear vein for spectrophotometric assay of reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS), and nitrite/nitrate (NOx; index of nitric oxide formation) before arsenic administration, seven days after arsenic administration, and seven days after antioxidant treatment. The total arsenic concentrations in hair and spot urine samples of rabbits before arsenic administration were 0.6 +/- 0.21 microg/g and 34.0 +/- 5.9 microg/L, respectively. Administration of arsenic trioxide significantly increased arsenic concentrations in hair and in urine to 2.8 +/- 0.40 microg/g (p<0.001) and 7372 +/- 1392.0 microg/L (p<0.001), respectively. Arsenic administration to rabbits significantly reduced GSH concentration (post-arsenic, 17.5 +/- 0.81 mg/dL vs. pre-arsenic, 32.0 +/- 0.76 mg/dL, p<0.001), increased TBARS concentration (post-arsenic, 8 +/- 1.1 microM vs. pre-arsenic, 5 +/- 0.7 microM, p<0.05), and NOx concentration (post-arsenic, 465 +/- 38.5 microM vs. pre-arsenic, 320 +/- 24.7 microM, p<0.001) as compared to the pre-arsenic levels. There was a negative correlation between TBARS and GSH concentrations (r=-0.464, p<0.01) and between NOx and GSH concentrations (r=-0.381, p<0.05) of intoxicated rabbits. The recovery of the depleted GSH was significantly greater in the polyphenols (77.0 +/- 12.0%) or VZS (67.0 +/- 17.0%) treatment groups compared with the placebo group (36.0 +/- 7.0%). The decrease in NOx level of arsenic-treated rabbits was significantly greater in polyphenols treatment group than the placebo group (60.0 +/- 9.0% vs. 17.0 +/- 6.0%, p<0.001). These results indicate that arsenic induces toxicity in rabbits associated with an increase in lipid peroxidation. Arsenic toxicity increases nitric oxide production in the body. Exogenous antioxidants such as polyphenols and recipe of vitamins, zinc, and selenium are useful for arsenic detoxification.

Speciation of arsenic metabolite intermediates in human urine by ion-exchange chromatography and flow injection hydride generation atomic absorption spectrometry

Biomethylation is considered as the principal metabolic and detoxification pathway for inorganic arsenic in human. The end products of methylation are less toxic and more readily excreted through urine. Therefore, speciation of metabolites in urine is essential to a better understanding of arsenic metabolism, health effects and detoxification ability of individuals exposed to arsenic through drinking water, food and environmental materials. Speciation of inorganic and methylated arsenic in urine is an analytical challenge and often requires expensive instrumentation. We have applied a relatively inexpensive technique for the separation and analysis of various arsenic species, such as, arsenite, arsenate, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in human urine. The technique is based on ion exchange chromatographic separation followed by flow injection hydride generation atomic absorption spectroscopy (FI-HG-AAS). The detection limit varies from 1.0 to 2.0 microg/L for various species. The technique has been successfully applied to speciation of arsenic metabolite intermediates in urine samples collected from patients in Hajiganj, a serious arsenic affected area in Bangladesh. Arsenite (AsIII) was found to be the major component in the urine from these patients. Our findings from patients in Hajiganj, Bangladesh are presented in this paper. The technique permits us to carry out arsenic speciation in urine, essential for toxicological studies and possible nutritional intervention in combating arsenic poisoning in Bangladesh.

Chemical fate of arsenic and other metals in groundwater of Bangladesh: experimental measurement and chemical equilibrium model

The presence of toxic level of inorganic arsenic in groundwater used for drinking in Bangladesh and neighboring India is unfolding as one of the worst natural disaster in the region. The purpose of this work is to ascertain the chemical fate of arsenic and other metals in groundwater of Bangladesh. A combination of techniques was used to measure 24 metals, 6 anions, Eh, pH, dissolved oxygen, conductivity, and temperature to understand the distribution of components which were then used in computational chemical equilibrium model, MINEQL+, for detailed speciation. It was found that the fate of arsenic and its speciation were inextricably linked to the formation of hydrous ferric oxide (HFO) and its kinetic. The HFO induced natural attenuation removes 50-75% of total arsenic in first 24 h through a first order kinetics. Adsorption on HFO is the predominant mode of removal of arsenic, iron, manganese, and most trace metals. The equilibrium model points to the presence of excess active sites for the removal of arsenic. MINEQL+ shows that significantly higher concentration of HFO forming iron is required to remove arsenic below maximum contamination level (MCL) of 50 microg/L than predicted by stoichiometry. The practical implication of this work is the prediction of water quality based on models.

Solid phase microextraction: measurement of volatile organic compounds (VOCs) in Dhaka City air pollution

A solid phase microextraction (SPME) technique was applied for the sampling of volatile organic compounds (VOCs) in ambient air polluted by two stroke autorickshaw engines and automobile exhausts in Dhaka city, Bangladesh. Analysis was carried out by capillary gas chromatography (GC) and GC-mass spectrometry (MS). The methodology was tested by insitu sampling of an aromatic hydrocarbon mixture gas standard with a precision of +/-5% and an average accuracy of 1-20%. The accuracy for total VOCs concentration measurement was about 7%. VOC's in ambient air were collected by exposing the SPME fiber at four locations in Dhaka city. The chromatograms showed signature similar to that of unburned gasoline (petrol) and weathered diesel containing more than 200 organic compounds; some of these compounds were positively identified. These are normal hydrocarbons pentane (n-C5H2) through nonacosane (n-C29H60), aromatic hydrocarbons: benzene, toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, 1,3,5-trimethylbenzene, xylenes, and 1-isocyanato-3-methoxybenzene. Two samples collected near an autorickshaw station contained 783000 and 1479000 microg/m3 of VOCs. In particular, the concentration of toluene was 50-100 times higher than the threshold limiting value of 2000 microg/m3. Two other samples collected on street median showed 135000 microg/m3 and 180000 microg/m3 of total VOCs. The method detection limit of the technique for most semi-volatile organic compounds was 1 microg/m3.