Esophageal small-cell cancer: study of a rare disease

Optimal treatment of esophageal small-cell cancer, a rare disease, lacks consensus. Based on its lung small-cell cancer analog, we hypothesized that chemotherapy with adjuvant radiotherapy would be optimal. This hypothesis was tested by studying the collective published literature. A meta-analysis of individual patients from 148 articles (1952-2010) explored treatment and outcome of 577 patients with esophageal small-cell cancer. Hazard function frailty modeling identified optimum therapy after accounting for article-level and patient-level heterogeneity. Fifty-nine percent of publications reported one patient and 25% five or more. Sixty-six percent of patients were men, mean age was 63 ± 11 years, and 64% had localized disease. One, 3-, and 5-year survival was 37%, 14%, and 11%, respectively. Survival variation among articles was substantial (P = 0.004), with survival improving across time (P < 0.0004). Chemotherapy was associated with better survival (hazard ratio [HR] = 0.53, 68% confidence interval [CI] = 0.44-0.65; P = 0.002) than surgery alone, radiotherapy alone, nonstandard therapy, or no therapy. Adding local therapy, either surgery (HR = 0.41, 68% CI = 0.34-0.51; P < 0.0001) or radiotherapy (HR = 0.33, 68% CI = 0.27-0.41; P < 0.0001), to chemotherapy further improved survival. Adding both did not provide further benefit. The strategy of borrowing from consensus treatment of lung small-cell cancer and analyzing the scarce available esophageal small-cell cancer literature may be beneficial in the study of rare diseases. It confirmed that chemotherapy should be the mainstay of therapy, with additional benefit from adjuvant therapy with either surgery or radiotherapy; both are not needed.

Heavy metal enrichment in the seagrasses of Lakshadweep group of islands--a multivariate statistical analysis

An assessment on heavy metal (Al, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Zn) accumulation by seven seagrass species of Lakshadweep group of islands was carried out using multivariate statistical tools like principal component analysis (PCA) and cluster analysis (CA). Among all the metals, Mg and Al were determined in higher concentration in all the seagrasses, and their values varied with respect to different seagrass species. The concentration of the four toxic heavy metals (Cd, Pb, Zn and Cu) was found higher in all the seagrasses when compared with the background values of seagrasses from Flores Sea, Indonesia. The contamination factor of these four heavy metals ranged as Cd (1.97-12.5), Cu (0.73-4.40), Pb (2.3-8.89) and Zn (1.27-2.787). In general, the Pollution Load Index (PLI) calculated was found to be maximum for Halophila decipiens (58.2). Results revealed that Halophila decipiens is a strong accumulator of heavy metals, followed by Halodule uninervis and Halodule pinifolia, among all the tested seagrasses. Interestingly, the small-leaved seagrasses were found to be efficient in heavy metal accumulation than the large-leaved seagrass species. Thus, seagrasses can better be used for biomonitoring, and seagrasses can be used as the heavy metal sink as the biomass take usually long term to get remineralize in nature.

Rhizobacterial population density and nitrogen fixation in seagrass community of Gulf of Mannar, India

Seagrass rhizosphere generally supports high bacterial population density which plays a major role in determining the nutrient cycles of the sea. Higher densities of total heterotrphic bacteria (26.3 x 10(6) CFU g(-1)), nitrogen fixing (27.3 x 10(3) CFUg(-1), ammonifying (44.66 x 10(6) MPN g(-1)) and nitrifying bacteria (42.33 X 10(6) MPN g(-1)) have been registered in the seagrass areas than the non seagrass area. In particular, all these rhizosphere microbial population was higher in Thalassia hemprichii. The rates of nitrogen fixation was recorded in the different species of seagrasses such as Enhalus acoroides (1.166 n mol g(-1) d(-1)), Halophila ovalis (0.166 n mol g(-1) d(-1)), Thalassia hemprichii(18.5 n mol g(-1) d(-1)), Cymodocea serrulata (10.5 n mol g(-1) d(-1)), Halodule uninervis (5.375 n mol g(-1) d(-1)) and Syringodium isoetifolium (0.666 n mol g(-1) d(-1)) using gas chromatography. The average nitrogen fixation by the seagrasses of Gulf of Mannar alone was estimated to be 7640.58 n mol m(-2) d(-1) and the contributions from the rhizosphere microbes will increase the quantity to many fold.

Prevalence rate of supernumerary teeth among non-syndromic South Indian population: An analysis

Aim:

Supernumerary teeth are considered as one of the most significant dental anomalies during the primary and early mixed dentition stage. The main objective of the study was to determine the prevalence rate of supernumerary teeth in the patients who reported to the Department of Oral Medicine and Radiology and to study the associated clinical complications.

Materials and Methods:

A longitudinal observational study was conducted of 2216 patients for a period of 4 months with the documentation of demographic data, the presence of supernumerary teeth, their location, and associated complications such as mechanical trauma, dental caries, and associated pathology.

Results:

The study recorded 27 supernumerary teeth from the examined 2216 patients. This yields a prevalence of 1.2%, with greater frequency in males which was 1.49% and in females the frequency was 0.85%. The greatest proportion of supernumerary teeth was found in the maxillary anterior region (77.8%). Out of this, 85.7% were classified as mesiodens based on their location. The displacement of adjacent teeth was the most common finding, followed by dental caries.

Conclusion:

The prevalence of supernumerary teeth in this study was 1.2% which is in agreement with that reported in similar studies and the maxillary mesiodens was the most common location. Displacement of adjacent teeth was the most common finding.

Difficulties encountered removing locked plates

INTRODUCTION

Locked plates are commonly used to obtain fixation in periarticular and comminuted fractures. Their use has also gained popularity in repairing fractures in osteoporotic bone. These plates provide stable fixation and promote biological healing. Over the last 3 years, we have used over 150 locked plates with varying success to fix periarticular fractures involving mainly the knee and ankle. In this study, we report our clinical experience and the difficulties encountered when removing locked plates in adult patients with a variety of indications including implant failure, infection, non-union and a palpable symptomatic implant.

METHODS

A retrospective analysis was performed of patients enrolled prospectively into a database. Included in the study were 36 consecutive adult patients who each underwent the procedure of locked plate removal in a single inner city level 1 trauma centre. Data collected included primary indication for fixation, indication for implant removal, time of the implant in situ, grade of operating surgeon and difficulties encountered during the procedure.

RESULTS

Implant removal was associated with a complication rate of 47%. The major problems encountered were difficulty in removing the locked screws and the implant itself. A total of ten cold welded screws were found in eight cases. Removal was facilitated by high speed metal cutting burrs and screw removal sets in all but one case, where a decision was made to leave the plate in situ.

CONCLUSIONS

The majority of studies investigating implant removal and problems encountered in doing so report a relatively high complication rate. With the advent of locking plates and their growing popularity, difficulties are now being seen intraoperatively when removing them. There is a paucity of data, however, specifically directed at locking plate removal. We recommend that surgeons should be aware of the potential complications while removing locked plates. Fluoroscopic control and all available extra equipment (mainly metal cutting burrs and screw removal sets) should be available in theatre.

Difficulties encountered removing locked plates

INTRODUCTION

Locked plates are commonly used to obtain fixation in periarticular and comminuted fractures. Their use has also gained popularity in repairing fractures in osteoporotic bone. These plates provide stable fixation and promote biological healing. Over the last 3 years, we have used over 150 locked plates with varying success to fix periarticular fractures involving mainly the knee and ankle. In this study, we report our clinical experience and the difficulties encountered when removing locked plates in adult patients with a variety of indications including implant failure, infection, non-union and a palpable symptomatic implant.

METHODS

A retrospective analysis was performed of patients enrolled prospectively into a database. Included in the study were 36 consecutive adult patients who each underwent the procedure of locked plate removal in a single inner city level 1 trauma centre. Data collected included primary indication for fixation, indication for implant removal, time of the implant in situ, grade of operating surgeon and difficulties encountered during the procedure.

RESULTS

Implant removal was associated with a complication rate of 47%. The major problems encountered were difficulty in removing the locked screws and the implant itself. A total of ten cold welded screws were found in eight cases. Removal was facilitated by high speed metal cutting burrs and screw removal sets in all but one case, where a decision was made to leave the plate in situ.

CONCLUSIONS

The majority of studies investigating implant removal and problems encountered in doing so report a relatively high complication rate. With the advent of locking plates and their growing popularity, difficulties are now being seen intraoperatively when removing them. There is a paucity of data, however, specifically directed at locking plate removal. We recommend that surgeons should be aware of the potential complications while removing locked plates. Fluoroscopic control and all available extra equipment (mainly metal cutting burrs and screw removal sets) should be available in theatre.

Negligence claims in UK total hip arthroplasty: a series of 167 consecutive cases

A review of negligence reports, detailing 227 complaints from the practices of two orthopedic surgeons, was undertaken. There were demonstrable differences in the number of complaints over leg-length discrepancy; femoral fracture and cup malposition when cemented versus uncemented implants were compared. Surgeons must appreciate the less forgiving nature of uncemented hip implants and the importance of preoperative planning particularly in the presence of abnormal anatomy.

Nephroprotective and antioxidant activities of Salacia oblonga on acetaminophen-induced toxicity in rats

Salacia oblonga, a woody climbing plant belonging to the family Celastaceae, is widely distributed in India and other southeast Asian countries. The genus Salacia have been used particularly for the treatment of diabetes, obesity, gonorrhoea, rheumatism, pruritus and asthma. Acetaminophen (APAP), used as an analgesic drug, produces liver and kidney necrosis in mammals at high doses. The aim of this study was to investigate the nephroprotective and antioxidant activities of the ethanol extract of Salacia oblonga (EESO) at the two dose levels of 250 and 500 mg/kg bw on APAP-induced toxicity in rats. The results showed that APAP significantly increases the levels of serum urea, creatinine, and reduces levels of uric acid concentration. The EESO reduces these by increasing anti-oxidative responses as assessed by biochemical and histopathological parameters. In conclusion, our results suggest that the EESO possesses nephroprotective and antioxidant effects against APAP-induced nephrotoxicity in rats.

(E)-1-[4-(Prop-2-yn-1-yl-oxy)phen-yl]-3-(3,4,5-trimeth-oxy-phen-yl)prop-2-en-1-one

The mol­ecule of the title chalcone derivative, C₂₁H₂₀O₅, consists of two substituted aromatic rings bridged by a prop-2-en-1-one group. The dihedral angle between the two benzene rings is 28.7 (7)°. In the crystal, mol­ecules are linked into C(10) chains running along the a axis by inter­molecular C—H⋯O hydrogen bonds, and the chains are cross-linked via C—H⋯π inter­actions.

Screening of marine actinobacteria for amylase enzymes inhibitors

Amylase inhibitor producing actinobacteria were isolated and characterized from terrestrial environment and there is no much report found from marine environment, hence in the present study, 17 strains isolated from the rhizosphere sediments of mangroves were tested for their amylase inhibition ability. Seawater requirement test for the growth of actinobacteria found that the strains SSR-3, SSR-12 and SSR-16 requires at least 50% and SSR-6 requires at least 25% seawater for their growth. The inhibition activity of both prokaryotic and eukaryotic amylase was tested by using Bacillus subtilis and Aspergillus niger. The maximum amylase activity (40mm) produced by the A. niger was taken as positive control, when the test actinobacteria strains grown in the medium they inhibited amylase activity and was evidenced by the reduction in inhibition zone (14-37 mm) similarly the amylase produced by the Bacillus subtilis was also recorded maximum (35 mm) amylase activity and was taken as positive control, and the test atinobacterial strains reduced enzyme action(12-33 mm) it varied levals. This indicates that the actinobacteria strains were controlled amylase enzyme activity in both the cases. The strain SSR-10 was highly effective and SSR-8 was less effective in inhibiting eukaryotic amylase produced by A. niger. The strain SSR-2 was effective and SSR-6 showed very less effect in inhibiting the prokaryotic amylase produced by the B subtilis.

4,5-Bis(1H-imidazol-1-ylmeth-yl)acridine monohydrate

In the title compound, C(21)H(17)N(5)·H(2)O, the dihedral angles between the acridine ring system and the imidazole rings are 78.8 (1) and 71.2 (1)°. The crystal packing is stabilized by O-H⋯N, C-H⋯O, C-H⋯π and π-π inter-actions [centroid-centroid separations = 3.732 (1) and 3.569 (1) Å].

Pediatric and neonatal tetanus: a hospital based study at eastern Nepal

A prospective hospital based study of childhood (<15 yrs) and neonatal tetanus cases from July 2004 - May 2006 was done to study the demography, clinical features and outcome of pediatric and neonatal tetanus cases at BPKIHS. During the study, 24 cases of tetanus were admitted from 9 districts including 5 neonatal tetanus. Among children with tetanus, 31.5% received 3 doses of DPT and 10.5% received TT vaccine as tetanus prophylaxis. In 16.0% children there was no recognizable injury preceding the disease. Otitis media preceded tetanus in 16.0%. All neonatal tetanus cases occurred following umbilical sepsis. Despite their mothers receiving 2 doses of TT during pregnancy, 2 neonates developed tetanus. A neonate delivered in hospital also developed neonatal tetanus. Average incubation period was 7.7 days and average onset time was 16.9 hours. Short onset time predicted the favorable outcome (p=0.005). Generalized tetanus cases were 75.0%, neonatal tetanus 21.0% and cephalic tetanus 4.0%. Generalized spasm was present in all cases. Common autonomic dysfunctions were fever, tachycardia and hypotension. Respiratory failure, aspiration pneumonia, rhabdomyolysis and seizure were common complications. Only one case received Intensive Care Unit (ICU) care. Survival rate was 21.1% for childhood tetanus and 40.0% for neonatal tetanus. Respiratory failure was the cause of death in majority. Study finds tetanus as an important disease in eastern Nepal, with substantial morbidity and mortality, primarily affecting the unvaccinated and inadequately vaccinated individuals. Despite lack of adequate resources, we can still manage tetanus cases with comparable outcome to other case series reported in the literatures.

[18F] Fluorodeoxyglucose positron-emission tomography-CT imaging of carotidynia

Carotidynia is an idiopathic syndrome characterized by pain over the carotid bifurcation without associated luminal pathologic process. The classification of carotidynia as a distinct disease rather than as a symptom has generated controversy in the literature. Recent reports, however, suggest that carotidynia is a distinct disease characterized by the presence of enhancing soft tissue in the carotid sheath. We describe findings of carotidynia on positron-emission tomography and CT that further support the classification of carotidynia as a distinct inflammatory disease.

Clinico-laboratory profile of haemolytic uremic syndrome

OBJECTIVE

To study the clinical profile, the spectrum of functional abnormalities, prognostic factors and outcome of children with haemolytic uremic syndrome (HUS).

MATERIALS AND METHODS

This is a prospective, descriptive, single centre, cohort study, conducted on 42 children during the period of January 2004 to January 2005.

RESULTS

The maximum numbers of cases were below 24 months of age with mean age of 26.6 months and male: female ratio of 2.8:1. Most of the cases (79%) occurred in the warmer months (April-September). The common clinical presentations were bloody diarrhoea, pallor, oliguria & anuria, fever, vomiting, abdominal distension and pain, involvement of central nervous system, chest and cardiovascular system and bleeding manifestations. The common haematological abnormalities were leucocytosis, thrombocytopenia, anaemia and features of haemolysis in the peripheral blood. Electrolyte abnormalities observed were in the form of hyponatremia, hypokalemia and hyperkalemia. Arterial blood gas analysis showed metabolic acidosis in 64% cases, where the estimations were done. The mean blood urea and serum creatinine levels were 113.7 mg/dL and 2.5 mg/dL, respectively. Stool examination showed blood in all cases. Urine examination showed microscopic haematuria and significant proteinuria in 74% and 38% cases, respectively. E. coli and Shigella were isolated in stool in three cases each and one case showed mixed growth of E. coli and Salmonella. The mortality rate was 21%. Significantly higher mortality was observed in females, patients presenting with complete anuria, leucocytosis, hyperkalemia and systemic involvement like central nervous system, cardio vascular system and chest.

CONCLUSIONS

Female sex, complete anuria, leucocytosis, extra renal involvement and hyperkalemia were associated with poor outcome.

Fryns syndrome: a lethal mesoectodermal birth defect with variable expression in a pair of monozygotic twins

We report a pair of twins with variable expressions of Fryns syndrome, both of whom died in the neonatal period. The syndrome is characterised by craniofacial dysmorphism, diaphragmatic hernia and distal limb hypoplasia. With this report, there are a total of 83 cases reported in the literature and this further serves to illustrate the clinical variability of this disorder.

Antioxidant effect of Cytisus scoparius against carbon tetrachloride treated liver injury in rats

The study was aimed to investigate the antioxidant activity of Cytisus scoparius L. (Family: Leguminosae) on CCl(4) (carbon tetrachloride) treated oxidative stress in Wistar albino rats. CCl(4) injection induced oxidative stress by a significant rise in serum glutamate oxaloacetate transaminases (SGOT), serum glutamate pyruvate transaminases (SGPT), lactate dehydrogenase (LDH) and thiobarbituric acid reactive substances (TBARS) along with reduction of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione-s-transferase (GST) and glutathione reductase (GRD). Pretreatment of rats with different doses of plant extract (250 and 500mg/kg) significantly lowered SGOT, SGPT, LDH and TBARS levels against CCl(4) treated rats. GSH and hepatic enzymes like SOD, CAT, GPx, GRD, and GST were significantly increased by treatment with the plant extract, against CCl(4) treated rats. The activity of extract at the dose of 500mg/kg was comparable to the standard drug, silymarin (25mg/kg). Based on these results, it was observed that Cytisus scoparius extract protects liver from oxidative stress induced by CCl(4) in rats and thus helps in evaluation of the traditional claim on this plant.

Cardiovascular risk factors in tobacco-chewers: a controlled study

BACKGROUND

Influence of habitual tobacco chewing on cardiovascular risk has not been well studied. To determine prevalence of major cardiovascular risk factors in subjects who habitually chew tobacco we performed a controlled study.

METHODS

A population based case-control study was performed in Bikaner in North-western India where the prevalence of tobacco-chewing is high. Successive 200 subjects who agreed to participate in the evaluation and had a history of isolated tobacco-chewing (range 10-60 years) were enrolled (Group III). The prevalence of major coronary risk factors- obesity, truncal obesity, hypertension, fasting hyperglycemia, and lipid levels were estimated using current guidelines. Electrocardiogram was also performed in all subjects. Chest radiography and treadmill stress test was done in subjects when indicated by symptoms. 200 age- and gender-matched controls who did not use tobacco in any form (Group I) and 200 subjects who had history of smoking bidis or cigarettes for more than 10 years (range 10-55 years) (Group II) were also evaluated.

RESULTS

The body-mass index and obesity were lowest in smoker group. Tobacco chewers had a significantly higher (p<0.001) systolic blood pressure (BP), diastolic BP, resting heart rate, total cholesterol, LDL cholesterol and triglycerides as compared to controls and was similar to smoker group. There was a significantly greater (p<0.01) prevalence of hypertension, hypercholesterolemia, hypertriglyceridemia, radiographic cardiomegaly and positive stress test in Group III as compared to controls. Prevalence of these risk factors was similar among Group II and Group III subjects. HDL cholesterol levels were the lowest in tobacco-chewing group (44.3+/-8.1 mg/dl) as compared to the Group I (48.4+/-7.8) and Group II (47.4+/-7.5) (p<0.001).

CONCLUSIONS

There is a significantly greater prevalence of multiple cardiovascular risk factors obesity, resting tachycardia, hypertension, high total and LDL cholesterol, and low HDL cholesterol, and electrocardiographic changes in tobacco users, chewing or smoking, as compared-to tobacco non-users. Chewing tobacco is associated with similar cardiovascular risk as smoking.

The modified McBride procedure: clinical, radiological, and pedobarographic evaluations

Nineteen patients (27 feet) with symptomatic hallux valgus who underwent modified McBride procedure were studied prospectively. The outcome measures included preoperative and postoperative American Orthopaedic Foot and Ankle Society's Hallux Metatarsophalangeal-Interphalangeal scoring, weight-bearing radiographs, and pedobarography using the EMED-SF*6 System. The average patient age was 49.7 years, and all patients were women. The average follow-up was 7 months. Results showed an average improvement in rating scale score from 53 to 87/100, in the hallux valgus angle from 32 degrees to 15 degrees, and in the first intermetatarsal angle from 15 degrees to 10 degrees. Pedobarographic analysis showed a statistically significant increase in the contact area of the hallux by 17.5% (P<.001), with a reduction of peak pressures of the hallux by 29% from 67.5+/-29.5 N/cm2 to 48+/-34 N/cm2 (P<.001; confidence interval, 9.887, 29.233) and the total foot by 8% from 89+/-26 N/cm2 to 82+/-25 N/cm2 (P<.05; CI, 0.727, 14.900). The overall satisfaction rate was 96%. We conclude that the modified McBride procedure has a role in patients with passively correctable hallux valgus and a supple metatarsocuneiform joint.

The spike osteotomy for hallux valgus: a clinical and radiological evaluation

A distal metatarsal osteotomy with soft tissue correction is a frequently performed operation to correct mild to moderate hallux valgus deformity. This is a prospective study of 28 feet in 25 patients who underwent spike osteotomy of the first metatarsal with medial capsulorraphy for symptomatic hallux valgus. The osteotomy is a distal metatarsal osteotomy with a spike fashioned in the plantar and lateral quarter of the proximal fragment and impacted into the trough created in the center of the distal fragment, providing lateral and plantar shift of the distal fragment. The American Orthopaedic Foot and Ankle Society's rating scale was used for functional assessment, and a visual analog scale gauged pain. The average follow-up was 27 months. The rating scale score improved from a mean preoperative value of 39/100 to 84/100. Twenty-six feet had complete pain relief, whereas 2 feet had a lesser degree of persistent metatarsalgia. A review of preoperative and postoperative radiographs showed that the hallux valgus angle improved from a mean 36 degrees preoperatively to 18 degrees postoperatively. Likewise, the mean 1 to 2 intermetatarsal angle improved from 13 degrees to 7.3 degrees. There was no incidence of avascular necrosis. Fourteen patients (16 feet) rated the outcome as excellent, 10 (11 feet) as good, and 1 patient with asymptomatic mild hallux varus deformity rated the result as fair. These results demonstrate that the spike osteotomy is a suitable operation for treatment of mild to moderate hallux valgus.

Prevalence of rheumatic heart disease in school children in Bikaner: an echocardiographic study

OBJECTIVE

To determine prevalence of rheumatic heart disease (RHD) using clinical and echocardiographic criteria and to study influence of socioeconomic status (SES) we studied school children in a north-western Indian town.

METHODS

3292 school children, age range 5-14 years, in two private schools, ten middle SES government schools and six low SES government schools were invited to participate in the study. 3002 (1837 boys, 1165 girls) were clinically examined (response 91%) of which 1042 were in private schools, 1002 in middle SES schools and 958 in low SES schools. Prevalence of cardiac murmurs and RHD based on clinical diagnosis was determined in school by a trained team of physicians. Those with a murmur were further evaluated by Doppler-echocardiography in the hospital. Group-specific and age-specific rates (prevalence/thousand) of murmurs and cardiac lesions were determined.

RESULTS

A significant cardiac murmur was observed in 55 subjects (18.3/1000) with similar prevalence in boys (20.7) and girls (14.6). The prevalence of murmur was significantly greater in children belonging to low SES schools (29.2/1000) as compared to middle SES (18.9) and higher SES schools (7.6). RHD prevalence based on clinical diagnosis was observed in 50 children (16.7/1000) and was similar in boys (19.1) and girls (12.9). Clinical RHD was more in the low SES school children (28.2/1000) as compared to middle (17.0) and high SES schools (5.8). RHD was demonstrated on echocardiography in 2 children (0.67/1000). Other prevalent cardiac lesions were congenital heart disease in 5 (1.66/1000) and mitral valve prolapse in 37 (12.3/1000).

CONCLUSIONS

There is a low prevalence of RHD in school children in this region compared to previous Indian studies. Cardiac murmurs are more prevalent among low SES children.

Monitoring of fogwater chemistry in the gulf coast urban industrial corridor: Baton Rouge (louisiana)

Seventeen fog events were sampled in Baton Rouge, Louisiana during 2002-2004 as part of characterizing wet deposition by fogwater in the heavily industrialized corridor along the Louisiana Gulf Coast in the United States. These samples were analyzed for chemical characteristics such as pH, conductivity, total organic and inorganic carbon, total metals and the principal ion concentrations. The dominant ionic species in all samples were NH4+, NO3-, Cl- and SO4(2-). The pH of the fogwater sampled had a mean value of 6.7 with two cases of acidic pH of 4.7. Rainwater and fogwater pH were similar in this region. The acidity of fogwater was a result of NO3- but partly offset by high NH4+. The measured gaseous SO2 accounted for a small percentage of the observed sulfate concentration, indicating additional gas-to-particle conversion of SO2 to sulfate in fogwater. The gaseous NOx accounted for most of the dissolved nitrate and nitrite concentration in fogwater. The high chloride concentration was attributable to the degradation of chlorinated organics in the atmosphere. The metal composition was traced directly to soil-derived aerosol precursors in the air. The major metals observed in fogwater were Na, K, Ca, Fe, Al, Mg and Zn. Of these Na, K, Ca and Mg were predominant with mean concentrations > 100 microM. Al, Fe and Zn were present in the samples, at mean concentrations < 100 microM. Small concentrations of Mn (7.8 microM), Cu (2 microM), Pb (0.07 microM) and As (0.32 microM) were also observed in the fogwaters, and these were shown to result from particulates (PM2.5) in the atmosphere. The contribution to both ions and metals from the marine sources in the Louisiana Gulf Coast was minimal. The concentrations of all principal ionic species and metals in fogwater were 1-2 orders of magnitude larger than in rainwater. Several linear alkane organic compounds were observed in the fogwater, representing the contributions from petroleum products at concentrations far exceeding their aqueous solubility. A pesticide (atrazine) was also observed in fogwater, representing the contribution from the agricultural activities nearby.

Identification of genetic alterations related to chemoresistance in epithelial ovarian cancer

OBJECTIVE

After the completion of primary chemotherapy, the majority of advanced ovarian cancer patients have persistent, chemoresistant disease. Comparative genomic hybridization (CGH) has been used to study genetic alterations that may be responsible for chemoresistance in ovarian cancer. CGH is a useful, genomewide screen but resolution is limited to 5-10 Mb. Recently, quantitative microsatellite analysis (QuMA), a TaqMan-based quantitative PCR technology, has been used for higher resolution of DNA copy number abnormalities. Our goal is to identify specific chromosomal aberrations correlated with platinum resistance.

METHODS

Snap-frozen ovarian tissue samples taken from 22 patients with ovarian cancer between 1994 and 1998 were analyzed. Patients whose ovarian cancer actually demonstrated growth during platinum-combination treatment or no objective evidence of regression following four to six cycles of therapy were considered to have clinically defined platinum-resistant disease. QuMA was carried out at the following loci using the ABI Prism 7700 (TaqMan) instrument with a microsatellite repeat probe: D3S1553, D3S1617, D5S464, D5S630, D6S1581, D6S446, D8S557, D19S208, D20S196, DXS1068. Fisher's exact test, exact logistic regression, and the Cochran-Armitage trend test were used. Because of multiple hypothesis testing, the P values were adjusted with the Bonferroni procedure to limit the familywise error rate to at most 5%.

RESULTS

Of the 22 patients, 12 (54.5%) were platinum-sensitive and 10 (45.5%) were platinum-resistant. When comparing sensitive and resistant patients, no statistically significant difference was noted among stage, grade, histology, and age (P = 0.1292, P = 1.0000, P = 1.0000, P = 1.0000, respectively). In the QuMA analysis, 10 of the 14 (71.4%) patients who had a low copy number of D6S1581 were platinum-resistant, while none of the patients with a normal or high copy number of D6S1581 were platinum-resistant. This was statistically significant when the marker data were treated as either a continuous or a categorical variable (P = 0.0410 and P = 0.0170, respectively). No other loci correlated significantly with platinum resistance.

CONCLUSIONS

D6S1581 was the only genetic marker, of those examined, significantly related to chemoresistance. Patients with a loss of D6S1581 are more likely to be platinum-resistant. Identification of genetic alterations associated with platinum resistance detected by QuMA may contribute to a better understanding of clinical behavior and chemotherapy treatment options for patients.

The role of tumor suppressor genes in esophageal cancer

Esophageal cancer remains one of the 10 most common cancers worldwide. Although patients with early lesions have a reasonable prognosis, most patients present with advanced disease resulting in an overall 5-year survival of 5-10%. Therefore, the current challenges in the management of esophageal cancer are to obtain a better understanding of the underlying molecular biological alterations to provide new treatment options. During the development of esophageal cancer, there is progression from a premalignant epithelium to a neoplasm that frequently demonstrates a heterogeneous mix of genetic alterations. The vast majority of esophageal cancers have inactivation of the p53 and p16 genes at an early stage followed by defects in genes such as APC, Rb and cyclin D1 at later stages of progression. There is also mounting evidence that numerous, specific regions throughout the genome are frequently lost in these cancers. As a result, we will in the next decade, likely see the discovery and characterizations of novel tumor suppressor genes that may be important in the development of esophageal cancer. The accumulating knowledge about the inactivation of the tumor suppressor genes could ultimately provide us with objective diagnostic tools, more accurate markers for prediction of malignant transformation from premalignant epithelium and facilitate the introduction of novel therapeutic options for the management of esophageal cancer.

Structural basis for the unusual properties of 2',5' nucleic acids and their complexes with RNA and DNA

To provide insights into the unusual properties of 2',5' nucleic acids (iso nucleic acids), that includes their rejection by Nature as information molecules, modeling studies have been carried out to examine if they indeed possess the stereochemical ability to form helical duplexes and triplexes, just as their 3',5' linked constitutional isomers. The results show that the formation of helical duplexes with 2',5' linkages demands a mandatory displacement of the Watson and Crick base pairs from the helical axis, as a direct consequence of the lateral shift of the sugar-phosphate backbone from the periphery towards the interior of the helix. Thus, both duplexes and triplexes formed with a 2',5'-sugar-phosphate backbone possess this intrinsic trait, manifested normally only in A type duplexes of DNA and RNA. It was found that only a 10-fold symmetric parallel triplex with isomorphous T.AT triplets is stereochemically favorable for isoDNA with 'extended' nucleotide repeats, unlike the 12-fold symmetric triplex favored by DNA. The wider nature of a 12-fold triplex, concomitant with mandatory slide requirement for helix formation in isoDNA, demands even larger displacement, especially with 'extended' nucleotide structural repeats, thereby violating symmetry. However, a symmetric triplex possessing higher twist, can be naturally formed for isoDNA with a 'compact' nucleotide repeat. Two nanosecond molecular dynamics simulation of a 2',5'-B DNA duplex, formed with an intrinsic base pair displacement of -3.3 A, does not seem to favor a total transition to a typical A type duplex, although enhanced slide, X-displacement, decrease in helical rise and narrowing of the major groove during simulation seem to indicate a trend. Modeling of the interaction between the chimeric isoDNA.RNA duplex and E. coli RNase H has provided a structural basis for the inhibitory action of the enzyme. Interaction of residues Gln 80, Trp 81, Asn 16 and Lys 99, of E. coli RNase H with DNA of the DNA.RNA hybrid, are lost when the DNA backbone is replaced by isoDNA. Based on modeling and experimental observations, it is argued that 2',5' nucleic acids possess restricted conformational flexibility for helical polymorphism. The inability of isoDNA to favor the biologically relevant B form duplex and the associated topological inadequacies related to nucleic acid compaction and interactions with regulatory proteins may be some of the factors that might have led to the rejection of 2',5' links.

Prognostic value of quantitative reverse transcription-polymerase chain reaction in lymph node-negative esophageal cancer patients

PURPOSE

In esophageal cancer, lymph node metastases are the strongest predictor of recurrence and poor outcome. However, many node-negative patients still recur despite a potentially curative resection. This is probably the result of microscopically occult metastases missed by histological examination. In this study, we used both standard, gel-based reverse transcription-PCR (RT-PCR) and Taqman quantitative RT-PCR (QRT-PCR) for carcinoembryonic antigen (CEA) mRNA to detect occult micrometastases in 387 lymph nodes from 30 histologically node-negative esophageal cancer patients.

EXPERIMENTAL DESIGN

CEA expression was compared with clinical outcomes to determine correlation with disease recurrence. For quantitative data, an optimum CEA expression level cutoff value was defined as the value that most accurately classified patients on the basis of disease recurrence. Kaplan-Meier survival curves were generated, and multivariate analyses were performed to evaluate the prognostic value of QRT-PCR.

RESULTS

CEA expression levels were above the optimum cutoff level in 12 tissue blocks, resulting in the identification of 11 CEA-positive patients. Of these patients, 9 suffered disease recurrence and 2 remain disease free. Of the 19 CEA-negative patients, there was 1 disease recurrence. The sensitivity and specificity for predicting disease recurrence were 90 and 90%, respectively. Kaplan-Meier analysis showed that CEA positivity resulted in significantly lower disease-free and overall survival (P <0.0001 and 0.0006 respectively). In multivariate analyses, CEA positivity measured by QRT-PCR was the strongest independent predictor of disease recurrence among other clinical and pathological factors examined.

CONCLUSIONS

QRT-PCR offers significant benefits over standard RT-PCR and identifies node-negative patients at high risk for recurrence.

Lysine 114 of antithrombin is of crucial importance for the affinity and kinetics of heparin pentasaccharide binding

Lys(114) of the plasma coagulation proteinase inhibitor, antithrombin, has been implicated in binding of the glycosaminoglycan activator, heparin, by previous mutagenesis studies and by the crystal structure of antithrombin in complex with the active pentasaccharide unit of heparin. In the present work, substitution of Lys(114) by Ala or Met was shown to decrease the affinity of antithrombin for heparin and the pentasaccharide by approximately 10(5)-fold at I 0.15, corresponding to a reduction in binding energy of approximately 50%. The decrease in affinity was due to the loss of two to three ionic interactions, consistent with Lys(114) and at least one other basic residue of the inhibitor binding cooperatively to heparin, as well as to substantial nonionic interactions. The mutation minimally affected the initial, weak binding of the two-step mechanism of pentasaccharide binding to antithrombin but appreciably (>40-fold) decreased the forward rate constant of the conformational change in the second step and greatly (>1000-fold) increased the reverse rate constant of this step. Lys(114) is thus of greater importance for the affinity of heparin binding than any of the other antithrombin residues investigated so far, viz. Arg(47), Lys(125), and Arg(129). It contributes more than Arg(47) and Arg(129) to increasing the rate of induction of the activating conformational change, a role presumably exerted by interactions with the nonreducing end trisaccharide unit of the heparin pentasaccharide. However, its major effect, also larger than that of these two residues, is in maintaining antithrombin in the activated state by interactions that most likely involve the reducing end disaccharide unit.

Correlation of expression of cyclooxygenase-2, vascular endothelial growth factor, and peroxisome proliferator-activated receptor delta with head and neck squamous cell carcinoma

Cyclooxygenase (COX) is the rate-limiting enzyme in the formation of prostaglandins from arachidonic acid. COX exists in 2 isoforms, COX-1 and COX-2. These isoforms are encoded by separate genes and demonstrate cell-specific expression and regulation. Peroxisome proliferator-activated receptor delta (PPARdelta) is a nuclear transcription factor that is activated by prostacyclin. Vascular endothelial growth factor (VEGF) is a proangiogenic factor that is up-regulated in various tumors. Vascular endothelial growth factor has been shown to interact with COX-derived prostaglandins in angiogenesis. To better understand the roles of these genes in head and neck squamous cell carcinoma (HNSCCA), we examined the differential expression of the COX1, COX2, VEGF, and PPARdelta genes in these tumors. Tissue samples from patients with HNSCCA were analyzed for COX-1, COX-2, VEGF, and PPARdelta messenger RNAs (mRNAs) by in situ hybridization. COX-1 and COX-2 mRNAs were also evaluated with Northern blot hybridization. Immunohistochemistry was used to analyze for COX-2 and PPARdelta proteins. Results showed focal areas of accumulation for COX-2, VEGF, and PPARdelta but not COX-1 in human HNSCCA. Northern blot hybridization showed higher levels of COX-2 mRNA in HNSCCA than in normal tissue. This suggests a supportive role of COX-2 in development and/or progression of HNSCCA. In addition, PPARdelta may be a receptor for COX-2-produced prostaglandins in HNSCCA. There is a potential role for selective COX-2 inhibitors in the treatment of these lesions.