Excited state complex formation between methyl glyoxal and some aromatic bio-molecules: a fluorescence quenching study

Fluorescence quenching of some important aromatic bio-molecules (ABM) such as 3-aminophthalhydrazide (luminol), tryptophan (Try), phenylalanine and tyrosine (Tyr) by methyl glyoxal (MG) has been studied employing different spectroscopic techniques. The interaction of MG with ABM in the excited state has been analysed using Stern-Volmer (S-V) mechanism. In the case of MG-luminol system time correlated single photon counting (TCSPC) technique has also been applied to explain the S-V mechanism. The bimolecular rate constants obtained are found to be higher than the rate constant for diffusion controlled process. A plausible explanation of the quenching mechanism has been discussed on the basis of hydrogen bonding, charge transfer and energy transfer interaction between the colliding species.

Estimation of the rate of unrecognized cross-contamination with mycobacterium tuberculosis in London microbiology laboratories

Isolates from patients with confirmed tuberculosis from London were collected over 2.5 years between 1995 and 1997. Restriction fragment length polymorphism (RFLP) analysis was performed by the international standard technique as part of a multicenter epidemiological study. A total of 2,779 samples representing 2,500 individual patients from 56 laboratories were examined. Analysis of these samples revealed a laboratory cross-contamination rate of between 0.54%, when only presumed cases of cross-contamination were considered, and 0.93%, when presumed and possible cases were counted. Previous studies suggest an extremely wide range of laboratory cross-contamination rates of between 0.1 and 65%. These data indicate that laboratory cross-contamination has not been a common problem in routine practice in the London area, but in several incidents patients did receive full courses of therapy that were probably unnecessary.

The prognostic significance of the tumour infiltrating lymphocyte count in stage I testicular seminoma managed by surveillance

The degree of lymphocytic infiltration is a significant determinant of outcome for a variety of malignancies, but its role in seminoma is unknown. 150 men with stage I testicular seminoma presenting between 1981 and 1993 were managed by surveillance following orchidectomy. The presence of tumour infiltrating lymphocytes (TILs) in each case was classified as high, intermediate or low. At a median follow-up of 9.4 years, 30 of the 150 men developed recurrent seminoma. On univariate analysis, the risk of relapse was associated with age < or =33 years (P=0.002), tumour diameter >6 cm (P=0.03), lymphatic or vascular invasion (P=0.04), tumour invasion of rete testis (P=0.05), and lower TIL count (P=0.02). On multivariate analysis, statistically significant predictors of risk of relapse were age < or =33 years (hazard ratio (HR) 4.6 (95% confidence intervals (CI): 1.7-12.2)) and tumour diameter >6 cm (HR 2.8 (CI: 1.2-6.5)). Lower TIL count was of borderline statistical significance (HR 1.8 (CI: 0.96-3.44)). The functional role of the lymphocytic infiltrate in testicular seminoma warrants further study.

Production and characterization of extracellular and intracellular tannase from newly isolated Aspergillus aculeatus DBF 9

A comparative study on the simultaneous production of extra and intracellular tannase was made from newly isolated fungal strain Aspergillus aculeatus DBF 9. This strain produced five times more intracellular enzyme within 24 h in liquid culture than the extracellular form. Maximum tannase production occurred in the culture broth containing 1-2% (w/v) tannic acid and 0.05-0.1% (w/v) glucose. The pH and temperature optima of both the enzymes were found at 5.0 and 50-60 degrees C, respectively. Extra and intracellular tannase showed good stability at higher temperature, pH values and salt (NaCl) concentration. These properties make the enzyme suitable for pollution control and bioprocess industry.

Prevalence of methicillin-resistant Staphylococcus aureus colonization in surgical patients, on admission to a Welsh hospital

Nosocomial infection with methicillin-resistant Staphylococcus aureus (MRSA) is on the increase and expensive to treat. Because surgical wound infection is one of the most frequent MRSA-induced infections with often disastrous consequences, it was decided to estimate the incidence and risk factors of MRSA colonization in surgical patients. All patients admitted to general surgical and orthopaedic wards were studied prospectively. At the time of admission, a detailed questionnaire was completed, nasal swabs and swabs of any pre-existing wound sites in each patient were sent for culture. Of 430 patients studied, 23 patients were positive for MRSA on admission. The prevalence of MRSA colonization in this study was 5.3% of whom 15 (65%) were nasal carriers and eight (35%) had MRSA colonization elsewhere. All nasal MRSA carriers had at least one documented hospital admission in the preceding year. Among the MRSA-positive patients, 10 (43%) either were admitted directly from, or had been previously admitted to, a nursing home. MRSA remains mainly a hospital-acquired infection although a significant proportion is acquired in the community. The risk factors identified were previous hospital admission, patients from nursing homes, male and aged over 70.

Characterization and drug sensitivity of four newly established colon adenocarcinoma cell lines to antifolate inhibitors of thymidylate synthase

Four new cell lines were established from the primary tumors of patients with untreated colorectal adenocarcinoma. Drug sensitivity and characterization of these cell lines was performed. Three of the four cell lines formed colonies in soft agar and all were tumorigenic in nude mice. The cell lines were morphologically similar but had differences in growth characteristics. Two of the cell lines, C18 (CCCL-4) and C29 (CCCL-6), had a longer doubling time compared with C85 (CCCL-1) and C86 (CCCL-2). The C18 and C29 cell lines had chromosome 17 abnormalities and evidence by immunohistochemistry of a mutant p53 and had decreased levels of thymidylate synthase and dihydrofolate reductase proteins, associated with decreased thymidylate synthase catalytic activity in C18 and no detectable activity in C29. Raltitrexed and GW1843U89 showed potent cytotoxic activity and all four cell lines displayed similar cytotoxicity to these folate thymidylate synthase inhibitors. The C18 and C29 cell lines were in general resistant to the other agents tested (methotrexate, 5-fluorouracil, nolatrexed) when compared with the C85 and C86 cell lines. These new cell lines may be useful for the study of colorectal adenocarcinoma and for evaluating new drugs or treatment schedules.

Study of primary amenorrhoea with special reference to cytogenetic evaluation

An attempt has been made to find out the proportion of genetic causes in cases of primary amenorrhoea and to analyse different chromosomal pattern. Cases were analysed according to clinical profile, X-ray, laparoscopy/pneumography, hormone profile, USG, Gonadal Biopsy and Cytogenetic study including Sex Chromatin (Barr body) and Karyotyping. Among the 72 cases studied, the aetiological factors were Mullerian duct abnormalities in 27 cases (37.5%) Gonadal agenesis in 13 cases (18.05%). Turner stigmata in 18 cases (25%), Y cell line in 6 cases (8.33%). Delayed menarche in 4 cases (5.55%), systemic disease like Tuberculosis and Idiopathic 2 cases (2.77%) each. Chromosomal aberration was seen in 24 cases (33.33%) and it comes second most common cause of primary amenorrhoea after mullerian duct abnormalities.

Optical dating of palaeochannel deposits in the Riverine Plain, southeastern Australia: testing the reliability of existing thermoluminescence dates

We present the first quartz optically stimulated luminescence (OSL) ages for palaeochannel sediments from the Riverine Plain in southeastern Australia. For young fluvial sediments, we agree with the notion that analysis of the leading edge of a dose distribution curve provides an objective method for determining the OSL age. For a modern flood deposit (less than 200 years old), the OSL ages estimated using the leading edge method (250 +/- 50 years) and by using the lowest 5% of the measured dose in single aliquots (230 +/- 50 years) agree within experimental errors. For older sediments, we suggest that the mean estimate of the dose distribution is likely to provide a reliable estimate of the OSL age. The luminescence ages suggest that the Coleambally and Kerarbury palaeochannel systems were active between 105 and 80 ky and 55 and 35 thousand years ago; the Yanco palaeochannel system could have been active as recently as 9000 years ago.

Optically stimulated luminescence signals of polymineral fine grains in the JSC Mars-1 soil simulant sample

The results of various experiments which characterise the optically stimulated luminescence (OSL) signals from polymineral fine grains of a Martian soil simulant sample (JSC Mars-1) are presented. The blue-green stimulated luminescence signal has greater thermal stability than the infrared stimulated luminescence signal for pre-heat temperatures between 250 degrees C and 400 degrees C. Fading tests over a 2 month storage period at 20 degrees C indicate that in some aliquots of JSC Mars-1 both the blue-green stimulated luminescence and the infrared stimulated luminescence signals fade by as much as 50%, whereas in others there is no evidence of significant fading. Dose recovery experiments demonstrate that equivalent dose (measured/given) ratio varies from aliquot to aliquot, and the underestimation in dose is less than 5% for at least one aliquot, for both the infrared and blue-green stimulated luminescence signals.

Dose and dose-rate dependence of optically stimulated signals in quartz: theoretical simulations

In a recent paper Bailey proposed a general model to describe many optically stimulated luminescence (OSL) and thermoluminescence properties of natural quartz. This model consists of five electron trapping centres and four recombination centres: one of the recombination centres is assumed to be radiative and the remaining non-radiative. This paper investigates some additional aspects of the Bailey model. Firstly, the single-aliquot regenerative-dose (SAR) method has been simulated using the model. It is shown that the simulated natural dose (2 Gy) given to the 'sample' in the simulation can be estimated to within approximately 2% using the SAR method. Furthermore, sensitivity-corrected OSL growth curves have been calculated over a dose range of 0 to 2500 Gy. Using the model, it is also demonstrated that the shape of the sensitivity-corrected OSL growth curve is independent of dose rate, for dose rates of 0.001 Gy x s(-1) and 0.1 Gy x s(-1), over a dose range of 0-500 Gy.

Retroviral transduction of human dihydropyrimidine dehydrogenase cDNA confers resistance to 5-fluorouracil in murine hematopoietic progenitor cells and human CD34+-enriched peripheral blood progenitor cells

Severe 5-fluorouracil (5-FU) toxicity has been reported among patients lacking dihydropyrimidine dehydrogenase (DPD) enzymatic activity. DPD is the principal enzyme involved in the degradation of 5-FU to 5'-6'-dihydrofluorouracil, which is further metabolized to fluoro-beta-alanine. We demonstrate here that overexpression of human DPD confers resistance to 5-FU in NIH3T3 cells, mouse bone marrow cells, and in human CD34+-enriched hematopoietic progenitor cells. An SFG-based dicistronic retroviral vector containing human DPD cDNA, an internal ribosomal entry site (IRES), and the neomycin phosphotransferase (Neo) gene was constructed (SFG-DPD-IRES-Neo). Transduced NIH3T3 cells demonstrated a 2-fold (ED50) increase in resistance to a 4-hour exposure of 5-FU in comparison to nontransduced cells. Expression of DPD was confirmed by Northern and Western blot analyses, and DPD enzyme activity was detectable only in transduced cells. Infection of mouse bone marrow cells with this retroviral construct resulted in an increased number of 5-FU-resistant CFU-GM colonies, compared to mock-transduced bone marrow in both 4-hour and 12- to 14-day exposures. Infection of human CD34+-enriched cells with this construct and incubation with 5-FU (10(-6) M) for 14 days also resulted in an increased number of 5-FU-resistant colonies. Retroviral transduction of human hematopoietic progenitor cells with a cDNA-expressing human DPD conferred resistance to 5-FU in NIH3T3 cells, mouse bone marrow cells, and human CD34+-enriched cells. These results encourage the use of this gene as a method to protect patients from 5-FU myelotoxicity.

Potential of the proteasomal inhibitor MG-132 as an anticancer agent, alone and in combination

Proteasomal activity is required for normal cellular functions including cell division, where entry and exit from mitosis is strictly regulated by cyclins and cyclin-dependent kinases which are among the important substrates of the proteasomal degradative machinery. Inhibitors of proteasomal activity have been shown to be effective inducers of apoptosis in tumor cells and may be useful as anticancer agents, either alone or in combination with other drugs. We have examined the effect of MG-132, a dipeptide proteasomal inhibitor, on various human cancer cell lines. We have also examined the effect of MG-132 on normal CD34+ enriched primary human peripheral blood stem cells. Our results indicate that MG-312 is a potent anticancer agent with cytotoxic effects on a variety of human cancer cell lines irrespective of their p53 status. MG-132 was found to be more effective in combination with drugs such as doxorubicin and etoposide that act in the S/G2-phase of the cell cycle via a mechanism that involves stabilization of cyclin B1 and increased expression of Bax. Further, MG-132 inhibits CFU-GM colony formation of the CD34+ enriched PBSC population and this inhibition correlates with release of cyt C into the cytosol.

Cholelithiasis in a child--an unusual presentation of Wilson's disease

A nine year old mentally retarded girl with moderate splenomegaly and ascites presented with chronic cholelithiasis. The presence of Kayser-Fleischer rings and low serum ceruloplasmin level confirmed the diagnosis of Wilson's disease. Cirrhosis of liver and recurrent episodes of hemolysis--these two common complications of Wilson's disease make an ideal setting for gall stone formation. Only three such cases have been reported worldwide and ours is the first case report from India. We suggest that cholelithiasis and splenomegaly in a child without evidence of congenital hemolytic disease should be taken as a suspect of Wilson's disease.

Sequence-dependent enhancement of cytotoxicity produced by ecteinascidin 743 (ET-743) with doxorubicin or paclitaxel in soft tissue sarcoma cells

Ecteinascidin 743 (ET-743) is a potent antitumor agent from the Caribbean tunicate Ecteinascidin turbinata and is presently in clinical trials for human cancers. To better understand how ET-743 might be used clinically, the present study used SRB assays to examine the cytotoxicity resulting from combining ET-743 with three other antineoplastic agents: doxorubicin (DXR), trimetrexate, and paclitaxel in different administration schedules in two soft tissue sarcoma cell lines, HT-1080 and HS-18, in vitro. Concurrent exposure of ET-743 with DXR resulted in synergistic interactions in both cell lines. Addition of ET-743 for 24 h before DXR was the most effective cytotoxic regimen against both cell lines. Morphological study by fluorescence microscopy revealed that combination treatment of both cells with ET-743 and DXR induced apoptosis. Exposure to paclitaxel before ET-743 was also an effective regimen. These results encourage studies of the combination of ET-743 and DXR in the treatment of soft tissue sarcoma, because each of these agents have activity in this disease.

Metallothionein expression in patients with small cell carcinoma of the lung: correlation with other molecular markers and clinical outcome

BACKGROUND

Patients with small cell carcinoma of the lung (SCLC) are known to have an extremely poor prognosis, with a 5-year survivor rate of only 5%. Chemotherapeutic drug resistance is a major obstacle to curative therapy in patients with SCLC.

METHODS

The authors evaluated retrospectively the expression of metallothionen (MT), proliferating cell nuclear antigen (PCNA), p53, and retinoblastoma gene product (RBGP) in biopsy samples from 58 patients with SCLC prior to standard chemotherapy. The objective was to study the correlation between MT and other molecular markers in SCLC and correlate these data with the clinical outcome of patients. The authors studied 28 short-term survivors (STS; survival < 24 months) and 30 long-term survivors (LTS; survival > 24 months).

RESULTS

In line with expectations, the authors found a strong inverse association between stage and survival. Of 58 patients with SCLC, 26 patients (45%; 17 STS and 9 LTS) showed MT expression, 55 patients (94%; 28 STS and 27 LTS) were positive for PCNA, 28 patients (48%; 16 STS and 12 LTS) were positive for p53, and only 6 patients (10%; 1 STS and 5 LTS) showed positivity for RBGP. On comparing the percent positivity of various markers in the two survivor groups, there was greater frequency of expression of MT, PCNA, and p53 and lower RBGP expression in the STS group compared with the LTS group. However, only the difference in expression of MT between the two survivor groups was statistically significant (Fisher exact test; P = 0.034). Multivariable analysis using a logistic regression model showed a significant association between MT expression and patient survival after adjusting for disease stage (chi-square test; P = 0.022). There was also a statistically significant association between MT expression and p53 expression (chi-square test; P = 0.001).

CONCLUSIONS

In this study, of the molecular markers studied, the authors demonstrated that only MT overexpression was independently predictive of short-term survival in patients with SCLC undergoing chemotherapy.

A randomized study of a flexible booster dosing regimen of VAQTA in adults: safety, tolerability, and immunogenicity

BACKGROUND

VAQTA (hepatitis A vaccine inactivated, Merck & Co., Inc., West Point, PA) is licensed for use in healthy adults in a two-dose schedule at 0 and 6 months.

OBJECTIVE

to determine whether the responses to a booster dose of VAQTA administered to adults 12 or 18 months after the first dose were similar to the response when the booster dose was administered 6 months after the first dose.

METHODS

healthy adults were randomized to receive 50-U of VAQTA at 6 (Group I), 12 (Group II), or 18 months (Group III) following receipt of Dose 1 on Day 0. Blood samples were collected immediately prior to Doses 1 and 2 and then, 4 weeks following Dose 2. Seropositivity rates (SPRs), geometric mean titers (GMTs) in milli-international units per milliliter (mIU/ml) and booster response rates (BRRs) were compared among treatment groups. Safety data were collected on Vaccination Report Cards.

RESULTS

no serious adverse experiences were reported, and the vaccine was well-tolerated by subjects in the three treatment groups. One month following the booster dose, SPRs and GMTs for Groups I, II, and III, respectively, were, 100% (102/102) and 6726.4 mIU/ml; 97.9% (93/95) and 4863.8 mIU/ml; 100% (86/86) and 6068.3 mIU/ml. The BRRs were 88.2% (Group I), 90.2% (Group II) and 94.2% (Group III).

CONCLUSION

responses to the booster dose were comparable regardless of the timing (i.e. 6, 12, or 18 months following Dose 1). Flexibility in the timing of the booster dose of VAQTA in adults would allow the vaccination schedule to be the same for adults, adolescents, and children and may increase the likelihood that adults receive the booster dose.

Uncommon presentation of medulloblastoma

INTRODUCTION

Medulloblastoma commonly occurs in children as a midline posterior fossa mass arising from the vermis, which appears as a hyperdense, homogeneously enhancing mass on CT scan and is associated with the clinical profile of posterior fossa syndrome. This unique clinico-radiological pattern is considered 'typical', but then medulloblastomas do not follow the typical clinico-radiological pattern in a significant number of cases.

PATIENTS

Out of the 42 cases of medulloblastoma operated on at SGPGIMS from 1988 to 1998, 29 cases were retrospectively and 13 cases were prospectively studied to detect the atypical clinico-radiological features. The typical radiological feature of a hyperdense homogeneously enhancing mass was seen in only 23 of the 42 patients, while 5 patients had hypodense nonenhancing masses, 13 had cystic changes, and 6 patients had calcifications in their tumours. Three patients presented with tumours in a very unusual location, i.e. the cerebellopontine angle cistern.

RESULTS

During follow-up, which ranged from a minimum period of 1 year to a maximum of 9 years, patients came back with metastases at very unusual sites. There were 5 cases of metastases in the frontal and subfrontal area (developed between 5 months and 5 years following surgery), and 1 patient developed a cervical intramedullary metastasis. Two patients developed abdominal metastases and ascites 2 years after definitive surgery and ventriculo-peritoneal shunting. Each of these 2 patients, however, had received a full course of craniospinal irradiation following surgery. Thus, we had a number of cases with an unusual clinical, radiological and metastatic pattern.

Colorimetric assay method for determination of the tannin acyl hydrolase (EC 3.1.1.20) activity

A new colorimetric method of tannase (tannin acyl hydrolase, EC 3.1.1.20) assay has been developed using its specific substrate tannic acid. It is based on the changes in optical density of substrate tannic acid after enzymatic reaction at 530 nm. The residual tannic acid was measured by a modified BSA precipitation method. This assay is very simple, reproducible, and very convenient, and with it tannase activity can be measured in relation to the growth of the organism.

Interface between drug use and sex work in Manipur

BACKGROUND

In India, drug use is seen predominantly as a problem among men. This study attempts to address the interface between drug use and sex work among women drug users in Manipur and the prevalence of HIV, hepatitis B and other sexually transmitted infections in them.

METHODS

This cross-sectional survey was conducted between April and October 1997 at the time of an ethnic clash in imphal, the capital of Manipur. Sixty-nine women drug users were interviewed through street-based outreach workers; 38 women (55%) were injecting drug users. Data were generated with the help of a semi-structured questionnaire on sociodemography, drug use practice and health issues after obtaining informed consent from the participants. Subsequently, consent was also obtained from 60 respondents for collecting blood for unlinked anonymous tests for HIV and hepatitis B surface antigen. Clinical examination for reproductive tract infections, offered to all the study participants, generated data on sexually transmitted diseases.

RESULTS

The prevalence of HIV infection in injecting drug users was 57% (20/35) compared to 20% (5/25) among non-injecting drug users (p = 0.001), although the prevalence of hepatitis B surface antigen was similar in the two groups, 48% v. 56%, respectively. Eighty per cent of the respondents, many of whom migrated following the ethnic clash, reported having sex with non-regular partners, two-thirds reported sex in exchange for money or drugs. Eighty-one per cent (29/36) of women who agreed to have a clinical examination had abnormal vaginal discharge, of which 10 had endocervical discharge. The presence of infection was confirmed in only 24% of those with vaginal discharge--4 had bacterial vaginosis and 3 trichomoniasis.

CONCLUSION

Environmental interventions to reduce civil unrest and forced migration have an important role to play in HIV containment. The high rate of HIV infection, and the probability of a high rate of sexually transmitted infections in women drug users suggests that a targeted intervention in this population group is a public health need. An innovative outreach strategy should be designed for effective implementation of interventions among women injecting drug users and non-injecting drug users who operate from the streets as sex workers to support their drug habit as well as livelihood.

Obesity predisposes to increased drainage following axillary node clearance: a prospective audit

BACKGROUND

Whilst sentinel node biopsy is being evaluated for optimising treatment of the axilla, axillary dissection remains the gold standard. Seroma formation, a common sequel to axillary dissection, has been shown to be associated with an increased incidence of wound infection, delayed healing, and lymphoedema. This study was conducted to evaluate the possible contributory role of obesity in axillary drainage following lymphatic dissection.

PATIENTS AND METHODS

This study comprised a prospective review of all patients undergoing axillary dissection in conjunction with mastectomy or wide local excision. The total in-patient axillary drainage and the average daily drainage was correlated with various clinical parameters, including obesity, type of surgery, level of axillary dissection and nodal involvement. The body mass index (BMI) was used as a measure of obesity.

RESULTS

During a 6-month period, axillary dissection was performed in 79 women. Nineteen patients were excluded. Patey mastectomy was performed on 33 (55%) and the remaining had breast conservation. The amount or duration of axillary drainage did not correlate with the type of operation, tumour histology, level of axillary dissection or the nodal status. Higher BMI correlated with increased mean daily axillary drainage and total volume drained, whilst in hospital. (Spearman correlation coefficient 0.42; P < 0.01).

CONCLUSION

Obesity predisposes to increased axillary drainage following nodal clearance.