Comparison of salvage radical prostatectomy vs. salvage ablation therapy for biopsy-proven radio-recurrent localized prostate cancer

INTRODUCTION

Radiation therapy for prostate cancer is associated with a 15-20% five-year recurrence rate. Patients with recurrence in the prostate only are candidates for salvage local therapies; however, there is no consensus on modality. This study uses registries at Memorial Sloan Kettering Cancer Center (MSKCC) and University of Western Ontario (UWO) to compare the oncologic outcomes of salvage radical prostatectomy (SRP) and salvage ablation (SA).

METHODS

A total of 444 patients were available for analysis. Due to intergroup differences, propensity score methodology was used and identified 378 patients with more comparable pre-salvage prostate-specific antigen (PSA), Gleason score, and primary radiation treatment. Patients underwent SRP at MSKCC and SA at UWO.

RESULTS

Of the 378 patients, 48 died of disease, with a 6.0-year median (interquartile range [IQR] 3.0, 9.7) followup among survivors; 88 developed metastases, with a median 4.6-year (IQR 2.3, 7.9) followup among metastasis-free survivors. There was a non-significantly higher rate of cancer-specific (hazard ratio [HR ] 1.02, 95% confidence interval [CI] 0.51, 2.06, p=0.9) and improved metastasis-free survival (HR 0.71, 95% CI 0.44, 1.13, p=0.15) among patients undergoing SA compared to patients undergoing SRP. There were 143 patients who received hormonal therapy, with higher rates of androgen deprivation therapy (ADT) in SA (HR 1.42, 95% CI 0.97, 2.08, p=0.068), although this did not meet conventional levels of significance.

CONCLUSIONS

This propensity score analysis of salvage therapy for radio-recurrent prostate cancer identified no statistically significant differences in oncologic outcome between SRP and SA; however, there was evidence of a lower risk of ADT in the cohort undergoing SRP. Given they are both potentially curative therapies, these treatments are viable options for men with clinically localized, radio-recurrent prostate cancer rather than ADT alone. Future research may further elucidate subpopulations that may be more amenable to either SRP or SA.

The Interactive Relationship Between Instructor Perceptions and Learner Personality on Surgical Skills Performance

OBJECTIVE

The objective of this study was to examine the association between learner personality and capacity to be trained (i.e., performance improvement) on a surgical task, and how instructor perceptions of the learners' capacity to be trained interact with learner personality and performance during training and feedback. There is meaningful heterogeneity in the degree of learner surgical skills acquisition despite receiving the same amount of training. While learner personality may independently contribute to skill acquisition, the instructor-learner feedback process is also important to consider. To better understand this interpersonal relationship, it is necessary to also consider instructor factors (i.e., perceptions), and how this may contribute to learner variability in skills training.

DESIGN

This exploratory study employed a prospective two-phase design. Medical and non-medical undergraduate students (N = 62) completed measures of personality and participated in two 20-minute training sessions with expert feedback 2 weeks apart, performing an end-to-side anastomosis on a low-fidelity model. Learner performance and instructors' perceptions of a learner's capacity to be trained were assessed.

PARTICIPANTS

Sixty-two medical and non-medical undergraduate students.

RESULTS

There was a significant interaction between learner Extraversion and instructor's perceptions of learner capacity to be trained. Higher learner Extraversion was only associated with an increase in performance improvement for those who were considered trainable (OR = 4.83, p = 0.017). Post hoc analysis revealed a significant difference in the amount of feedback provided to participants who were considered trainable (M = 9.45) versus not trainable (M = 16.48).

CONCLUSIONS

This study highlights the importance of both individual learner factors and instructor perceptions on surgical skill acquisition.

Long-term Testis Cancer Survivors in Canada-Mortality Risks in a Large Population-based Cohort

BACKGROUND

Testis cancer (TC) patients are young with excellent cancer prognosis. Hence, the risk of late-onset treatment-related morbidity and mortality is of concern due to longer survival after treatment.

OBJECTIVE

We set to characterize long-term survival of TC patients through a Canadian population dataset.

DESIGN SETTING AND PARTICIPANTS

We used a population-based dataset, the Canadian Census Health and Environment Cohort (CanCHEC), to identify individuals diagnosed with TC between 1991 and 2010. We compared them with all other male individuals without TC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was mortality due to cardiovascular disease (CVD) or nontesticular malignancy. Mann-Whitney or chi-square test was used where applicable. Data were analyzed using a Cox proportional hazard model with and without matching.

RESULTS AND LIMITATIONS

We identified 1950 individuals with TC. We compared them with 1 300 295 men with no TC. There were 335 deaths in the study group during the study period (17.2%) with a mean follow-up of 19.6 yr. TC patients were at increased risk of death from secondary malignancies (hazard ratio [HR] 1.63, 95% confidence interval [CI] 1.39-1.91; p < 0.0001) with specific risks for hematologic neoplasms (HR 3.86, 95% CI 2.78-5.37; p < 0.001) and other malignancies (HR 2.41, 95% CI 1.76-3.29; p < 0.001). Gastrointestinal, hematologic, and respiratory toxicities were the most common secondary malignancies leading to death. When stratified according to histology, nonseminoma (NS) patients were at significantly increased risk of death from CVD (HR 2.03, 95% CI 1.27-3.25; p = 0.0032). Individuals with seminoma were at increased risk of death from other nontestis neoplasms (HR 1.46, 95% CI 1.17-1.82; p = 0.0007), specifically hematologic neoplasms (HR 2.09, 95% CI 1.18-3.72; p = 0.0118).

CONCLUSIONS

NS patients are at increased risk of CVD-related death, whereas seminoma patients are at increased risk of death from non-testis-related malignancies.

PATIENT SUMMARY

We report long-term mortality following diagnosis of testis cancer. Nonseminoma patients have an increased risk of death from cardiovascular disease, while seminoma patients have an increased risk of death from secondary malignancies.

Prostatic dystrophic calcification following salvage cryotherapy for prostate cancer - an under-reported entity?

BACKGROUND

Salvage cryoablation (SCA) is an accepted treatment for radio-recurrent prostate cancer with well-established oncological and functional outcomes. Based on one of the longest reported prospective follow-ups in the literature (median 12 years) on 187 patients, this study reports what appears to be an under-appreciated finding in eight patients with dystrophic calcifications (DC) of the prostate following SCA, causing severe bladder outlet obstruction.

MATERIALS AND METHODS

Between 1995 and 2004, 187 patients underwent SCA, with a median follow-up of 12 years. This database was reviewed for functional and oncological outcomes and DC were evaluated.

RESULTS

Functional data was available in 85 patients, amongst whom eight patients were found to develop DC (9.4%) proven when the patients presented with urinary difficulties and attempted transurethral resection was undertaken for bladder outlet obstruction. Mean time for emergence of significant symptoms of bladder outlet obstruction was 8.6 years from SCA (standard deviation (SD) = 6 years). All eightpatients required permanent drainage (seven suprapubic catheters, one nephrostomy). All patients with DC experienced biochemical recurrence (BCR), compared to 57.1% of the patients with no DC (p = 0.01).

CONCLUSION

DC following SCA appears to be an under-reported late adverse effect which may only become evident with long follow-up, and should be included in preoperative counselling.

Magnetic resonance imaging-guided transurethral ultrasound ablation in patients with localised prostate cancer: 3-year outcomes of a prospective Phase I study

OBJECTIVES

To report the 3-year follow-up of a Phase I study of magnetic resonance imaging (MRI)-guided transurethral ultrasound ablation (TULSA) in 30 men with localised prostate cancer. Favourable 12-month safety and ablation precision were previously described.

PATIENTS AND METHODS

As a mandated safety criterion, TULSA was delivered as near whole-gland ablation, applying 3-mm margins sparing 10% of peripheral prostate tissue in 30 men. After 12-month biopsy and MRI, biannual follow-up included prostate-specific antigen (PSA), adverse events (AEs), and functional quality-of-life assessment, with repeat systematic biopsy at 3 years.

RESULTS

A 3-year follow-up was completed by 22 patients. Between 1 and 3 years, there were no new serious or severe AEs. Urinary and bowel function remained stable. Erectile function recovered by 1 year and was stable at 3 years. The PSA level decreased 95% to a median (interquartile range) nadir of 0.33 (0.1-0.4) ng/mL, stable to 0.8 (0.4-1.6) ng/mL at 3 years. Serial biopsies identified clinically significant disease in 10/29 men (34%) and any cancer in 17/29 (59%). By 3 years, seven men had recurrence (four histological, three biochemical) and had undergone salvage therapy without complications (including six prostatectomies). At 3 years, three of 22 men refused biopsy, and two of the 22 (9%) had clinically significant disease (one new, one persistent). Predictors of salvage therapy requirement included less extensive ablation coverage and higher PSA nadir.

CONCLUSION

With 3-year Phase I follow-up, TULSA demonstrates safe and precise ablation for men with localised prostate cancer, providing predictable PSA and biopsy outcomes, without affecting functional abilities or precluding salvage therapy.

The history of cryosurgery in Canada: A tale of two cities

Although not commonly available in Canada, cryosurgery (cryoablation) for prostate cancer has been practiced in many countries. The field of cryoablation has evolved significantly over the past 30 years. Two prostate cryoablation programs were started in Canada in the early 1990s, in London, ON and Calgary, AB, focusing, respectively, on salvage therapy following radiation failure and primary local treatment. This article chronicles the development of the two programs and outlines the scientific and clinical contributions by investigators at the two centers.

Anatomical characterization of the inguinal lymph nodes using microcomputed tomography to inform radical inguinal lymph node dissections in penile cancer

BACKGROUND & OBJECTIVES

Radical inguinal lymph node dissections (rILND) for penile cancer risk significant postoperative lymphocele and lymphedema. However, reducing the risk of lymphatic complications is limited by our understanding of lymphatic anatomy. Therefore, this study aims to elucidate the lymphatic anatomy within the current surgical borders of a rILND.

METHODS

To visualize the position of the lymph nodes, tissue packets excised from the inguinal region of five fresh, male cadavers were imaged using microcomputed tomography (µCT). To standardize the position, rotation and size between specimens, each lymph node packet was aligned using a Generalized Procrustes analysis.

RESULTS

There was a median of 13.5 lymph nodes (range = 8-18) per packet, with the majority (99%) clustered within a 6 cm radius of the saphenofemoral junction; a region 39%-41% smaller than current surgical borders. No difference existed between the number of nodes between sides, or distribution around the saphenofemoral junction.

CONCLUSIONS

This study provides the first 3D, in situ, standardized characterization of lymph node anatomy in the inguinal region using µCT. By using knowledge of the normal lymphatic anatomy, this study can help inform the reduction in borders of rILND to limit disruption and ensure a complete lymphadenectomy.

Long-term outcomes of two ablation techniques for treatment of radio-recurrent prostate cancer

BACKGROUND

In men with recurrence of prostate cancer post radiation therapy, further treatment remains a challenge. The default salvage option of androgen-deprivation therapy (ADT) has adverse effects. Alternatively, selected men may be offered salvage therapy to the prostate. Herein, we present long-term oncological outcomes of two whole-gland ablation techniques, cryotherapy (sCT) and high-intensity-focused ultrasound (sHIFU).

METHODS

Men undergoing sCT (1995-2004) and sHIFU (2006-2018) at Western University were identified. Oncological endpoints included biochemical recurrence (BCR), ADT initiation, metastases, castration resistance (CRPC), and prostate cancer-specific mortality (PCSM). Survival analysis with competing risks of mortality was performed. Multivariable analysis was performed using Fine and Gray regression.

RESULTS

A total of 187 men underwent sCT and 113 sHIFU. Mean (SD) age of the entire cohort was 69.9 (5.9 years), median pre-radiation PSA 9.6 ng/ml (IQR 6.1-15.2), and pre-salvage PSA 4.5 ng/ml (IQR 2.8-7.0). Median total follow-up was 116 months (IQR 67.5-173.8). A total of 170 (57.6%) developed BCR, 68 (23.4%) metastases, 143 (49.3%) were started on ADT, 58 (20.1%) developed CRPC, and 162 (56%) patients died of which 59 (36.4%) were of prostate cancer. On multivariable analysis, sHIFU (HR 1.65, 95% CI 1.15-2.36, p = 0.006) and pre-salvage PSA (HR 1.09, 95% CI 1.06-1.13, p < 0.0001) were associated with a higher risk of BCR. Similarly, sHIFU patients had a higher risk of CRPC (HR 2.31, 95% CI 1.23-4.35, p = 0.009). The cumulative incidence (for both treatments) of PCSM was 16.5% (95% CI 12.2-21.4%) at 10 years and 28.4% (95% CI 22.1-34.9%) at 20 years, with no difference between treatment modalities. Pre-salvage PSA was a common predictor for the measured oncological outcomes.

CONCLUSIONS

Although sHIFU had higher BCR and CRPC rates, there were no differences in PCSM when compared with sCT. The long-term oncological data on two ablation techniques highlighted that only 50% of patients started ADT after 10-year follow-up.

Examining Mannitol Use in Kidney Cancer Surgery: A Cautionary Tale of Extrapolated Surgical Data

Mannitol for renal protection during partial nephrectomy is common but unsupported by evidence from clinical trials. The impact of mannitol on renal physiology includes both beneficial and harmful effects. Current understanding of renal ischemia reperfusion injury suggests potentially targetable processes that have a lower potential risk.

Aspiration and sclerotherapy of hydroceles and spermatoceles/epididymal cysts with 100% alcohol

OBJECTIVE

To evaluate the efficacy of aspiration and sclerotherapy with 100% alcohol for the primary treatment of benign scrotal cysts.

METHODS

From March 2014 to March 2018, 114 patients were identified who underwent their first aspiration and sclerotherapy procedure (80 hydroceles and 34 spermatoceles/epididymal cysts). The procedure was carried out in the outpatient clinic with local anaesthesia. A 16-gauge IV catheter is used to puncture the sac under aseptic conditions. The volume of alcohol instilled was 10% of the aspirated volume (maximum of 50 mL). Patients were then observed in the waiting room and completed a questionnaire. Urology clinic follow up was scheduled at 6 weeks.

RESULTS

At follow up, 54 patients (67.5%) with hydroceles and 25 patients (73.5%) with spermatoceles/epididymal cysts had resolution after a single procedure. A second procedure was offered if fluid collection persisted, of which 71% of patients with hydroceles and 100% of patients with spermatoceles/epididymal cysts had a successful outcome. At a median of 31 months post-initial procedure, the overall success rate, after at most two procedures, was 80% for hydroceles and 85% for spermatoceles/epididymal cysts. The complication rate was low (6%). Almost all patients were happy to undergo the procedure again, if needed. Persistence following aspiration and sclerotherapy were more likely to occur in younger patients (45.4 versus 61.2 years, P = 0.001). Persistence was not related to the volume of fluid aspirated.

CONCLUSION

Aspiration and sclerotherapy with alcohol is a reliable, safe and effective technique for treatment of benign scrotal cysts.

Enhancement of heavy metal tolerance and accumulation efficiency by expressing Arabidopsis ATP sulfurylase gene in alfalfa

Transgenic alfalfa (Medicago sativa L.) plants overexpressing the Arabidopsis ATP sulfurylase gene were generated using Agrobacterium-mediated genetic transformation to enhance their heavy metal accumulation efficiency. The ATP sulfurylase gene was cloned from Arabidopsis, following exposure to vanadium (V) and lead (Pb), and transferred into an Agrobacterium tumefaciens binary vector. This was co-cultivated with leaf explants of the alfalfa genotype Regen SY. Co-cultivated leaf explants were cultured on callus and somatic embryo induction medium, followed by regeneration medium for regenerating complete transgenic plants. The transgenic nature of the plants was confirmed using PCR and southern hybridization. The expression of Arabidopsis ATP sulfurylase gene in the transgenic plants was evaluated through RT-PCR. The selected transgenic lines showed increased tolerance to a mixture of five heavy metals and also demonstrated enhanced metal uptake ability under controlled conditions. The transgenic lines were fertile and did not exhibit any apparent morphological abnormality. The results of this study indicated an effective approach to improve the heavy metal accumulation ability of alfalfa plants which can then be used for the remediation of contaminated soil in arid regions.

Heavy metal concentrations in some gastropods and bivalves collected from the fishing zone of South India

The present study investigates heavy metal concentrations in gastropods and bivalves collected from major fishing centers in South India. Three gastropods, Bursa spinosa, Tibia curta, and Murex trapa, and two bivalves, Perna viridis and Villoritta cyprinoids, were collected for the analysis of heavy metals. The metals in the present study followed the order Mg>Ca>Zn>Fe>Cu>Mn>Cr>Pb>Ni>Co>Cd. Trace metal concentrations in the soft tissue of the molluscs varied as follows: for Cd: 0.04-5.33, Co: 0.09-0.87, Cr: 2.18-7.59, Cu: 9.54-37.02, Mn: 1.30-8.50, Ni: 0.94-3.21, Pb: 1.16-2.64 and Zn: 68.16-113.64mgkg^-1. Metal concentrations in all the species were below the limits proposed by the World Health Organization, except for Pb and Cd. This baseline study suggests that the levels of toxic metals in M. trapa, T. curta, and B. spinosa should be continuously monitored to assess the fate and effects of these metals in this fragile ecosystem.

Predominance and sources of alkane and fatty acid biomarkers in the surface sediments of Chitrapuzha River (South India)

Surface sediment samples were collected from Chitrapuzha (Cochin) estuarine system to identify the natural and anthropogenic origin of organic matter. The distribution and sources of organic matter were assessed with the help of fatty acid and alkane biomarkers. Fatty acids ranging from C12 to C28 were identified and C16:0 was the most abundant fatty acid, which contributed between 23.5 % and 52.4 % to total fatty acids. The low levels of polyunsaturated fatty acids indicate the effective bacterial recycling of algal fatty acids during the whole settling and depositing process. Aliphatic hydrocarbons ranging from C12 to C33 were identified and the total concentration ranged from 7876 to 43,357 ng g(-1). The presence of unresolved complex mixtures and lower pristane to phytane ratios indicates the petroleum contamination in the study area.

Biomonitoring of trace metal pollution using the bivalve molluscs, Villorita cyprinoides, from the Cochin backwaters

Trace metal concentrations in the muscle of the bivalve Villorita cyprinoides from the Cochin backwaters (southwest coast of India) were investigated during the monsoon, post-monsoon and pre-monsoon periods. The seasonal average ranges of metals (μg g(-1), dry weight) in the bivalve were as follows: Fe (18,532.44-28,267.05), Co (23.25-37.58), Ni (10.56-19.28), Cu (3.58-11.35), Zn (48.45-139.15), Cd (1.06-1.50) and Pb (3.05-4.35). The marginally elevated metal concentrations in bivalve muscles are probably related to high influx of metals as a result of pollution from the industries and agricultural fields with consequent increased bioavailability of metals to the bivalve. Evaluation of the risks to human health associated with consumption of the bivalves suggested that there is no health risk for moderate shellfish consumers. A regular and continuous biomonitoring program is recommended to establish V. cyprinoides as a bioindicator for assessing the effects of trace metal pollution and to identify future changes to conserve the "health" of this fragile ecosystem.

Inhalation gases or gaseous mediators as neuroprotectants for cerebral ischaemia

Ischaemic stroke is one of the leading causes of morbidity and mortality worldwide. While recombinant tissue plasminogen activator can be administered to produce thrombolysis and restore blood flow to the ischaemic brain, therapeutic benefit is only achieved in a fraction of the subset of patients eligible for fibrinolytic intervention. Neuroprotective therapies attempting to restrict the extent of brain injury following cerebral ischaemia have not been successfully translated into the clinic despite overwhelming pre-clinical evidence of neuroprotection. Therefore, an adequate treatment for the majority of acute ischaemic stroke patients remains elusive. In the stroke literature, the use of therapeutic gases has received relatively little attention. Gases such as hyperbaric and normobaric oxygen, xenon, hydrogen, helium and argon all possess biological effects that have shown to be neuroprotective in pre-clinical models of ischaemic stroke. There are significant advantages to using gases including their relative abundance, low cost and feasibility for administration, all of which make them ideal candidates for a translational therapy for stroke. In addition, modulating cellular gaseous mediators including nitric oxide, carbon monoxide, and hydrogen sulphide may be an attractive option for ischaemic stroke therapy. Inhalation of these gaseous mediators can also produce neuroprotection, but this strategy remains to be confirmed as a viable therapy for ischaemic stroke. This review highlights the neuroprotective potential of therapeutic gas therapy and modulation of gaseous mediators for ischaemic stroke. The therapeutic advantages of gaseous therapy offer new promising directions in breaking the translational barrier for ischaemic stroke.

The destination of Pacific Island health professional graduates from a New Zealand university

BACKGROUND

There is a shortage of health professionals in Pacific Island states and territories, and a need in New Zealand for Pacific health professionals to serve Pacific communities.

METHODS

A cross-sectional postal survey was conducted to investigate retention of Pacific graduates. All graduates of Pacific ethnicity or nationality from the University of Otago in the years 1994 to 2004 in medicine, dentistry, pharmacy, physiotherapy and medical laboratory science were included.

RESULTS

The response rate was 59% (75 out of 128). Only 7% of respondents were working in the Pacific Islands (12% of non-residents and 4% of New Zealand residents), though the proportion in the whole cohort could be up to 20%. One third intended to work in Pacific communities in New Zealand or the Pacific Islands in the future. Factors that would favour such an intention were an adequate income, job availability, and good working conditions.

CONCLUSIONS

Retention of graduates in the Pacific Islands is poor and measures to improve retention are needed.

Toxic metals enrichment in the surficial sediments of a eutrophic tropical estuary (Cochin backwaters, Southwest Coast of India)

Concentrations and distributions of trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in surficial sediments of the Cochin backwaters were studied during both monsoon and pre-monsoon periods. Spatial variations were in accordance with textural charaterstics and organic matter content. A principal component analysis distinguished three zones with different metal accumulation capacity: (i) highest levels in north estuary, (ii) moderate levels in central zone, and (iii) lowest levels in southern part. Trace metal enrichments are mainly due to anthropogenic contribution of industrial, domestic, and agricultural effluents, whose effect is enhanced by settling of metals due to organic flocculation and inorganic precipitation associated with salinity changes. Enrichments factors using Fe as a normalizer showed that metal contamination was the product of anthropogenic activities. An assessment of degree of pollution-categorized sediments as moderately polluted with Cu and Pb, moderately-to-heavily polluted with Zn, and heavily-to-extremely polluted with Cd. Concentrations at many sites largely exceed NOAA ERL (e.g., Cu, Cr, and Pb) or ERM (e.g., Cd, Ni, and Zn). This means that adverse effects for benthic organisms are possible or even highly probable.

Melatonin treatment following stroke induction modulates L-arginine metabolism

The efficacy of melatonin treatment in experimental stroke has been established. Some of the neuroprotective properties have been attributed to its anti-oxidant and anti-inflammatory effects. Nitric oxide synthases (NOS) and cyclooxygenases (COX) are considered to have a significant role in the inflammatory milieu occurring in acute stroke. While previous reports have shown that pretreatment with melatonin in a stroke model can modulate NOS isoforms, the effect of post-treatment with melatonin on l-arginine metabolism has not been investigated. This study initially examined the effect of melatonin (1 nm-1 mm) on l-arginine metabolism pathways in human fibrosarcoma fibroblasts (HT-1080) fibroblasts. Evidence of neuroprotection with melatonin was evaluated in rats subjected to middle cerebral artery occlusion (MCAO). Animals were treated with three daily doses of 5 mg/kg i.p., starting 1 hr after the onset of ischemia. Constitutive NOS activity but not expression was significantly increased by in vitro exposure (72 hr) to melatonin. In addition, melatonin treatment increased arginase activity by increasing arginase II expression. In vivo studies showed that melatonin treatment after MCAO significantly inhibited inducible NOS activity and attenuated expression of the inducible isoform, resulting in decreased total NOS activity and tissue nitrite levels. COX activity was significantly reduced with melatonin treatment. The neuroprotective anti-inflammatory effects of melatonin were consistent with the substantial reduction in infarct volume throughout the cortex and striatum and recovery of mitochondrial enzyme activities. The evidence presented here suggests that modulation of l-arginine metabolism by melatonin make it a valuable neuroprotective therapy for stroke.

Distribution of organophosphorus pesticides in the bed sediments of a backwater system located in an agricultural watershed: influence of seasonal intrusion of seawater

This article focuses on the temporal and spatial distribution of three organophosphorous pesticides-malathion, methyl parathion, and chlorpyrifos-in the sedimentary environment of a backwater ecosystem, Kuttanad backwaters, situated in Kerala, India. Based on salinity distribution, geographic characteristics, and human activities prevailing in the area, the study area was divided into three zones: zone 1 with riverine characteristics, zone 2 with freshwater characteristics during and after the monsoon season and estuarine characteristics during the premonsoon season, and zone 3 with estuarine characteristics. The organophosphorus pesticides in the study area showed the order of enrichment as chlorpyrifos >malathion >methyl parathion. While studying the variations in pesticide concentrations seasonally, higher concentrations were observed during the premonsoon monsoon season, with the concentrations being lower than the detectable level. Sediment characteristics, such as pH, texture, organic carbon, moisture content, etc., had reflective effect on the degradation rates of pesticides. The runoff water from the paddy fields made a larger contribution of pesticide pollution to the study area.

Cerebral heme oxygenase 1 and 2 spatial distribution is modulated following injury from hypoxia-ischemia and middle cerebral artery occlusion in rats

The regional and cellular distribution of heme oxygenase (HO)-1 and -2 following cerebral ischemia has not been ascertained. Employing the transient middle cerebral artery occlusion (MCAO) and hypoxia-ischemia (HI) models of unilateral brain injury, the aim was to elucidate immunolocalization of HO-1 and HO-2. Animals were sacrificed 3 days post-ischemia and immunohistochemistry and Western blotting were utilized to determine HO-1 and HO-2 expression. In the ipsilateral hemisphere following HI, HO-1 immunoreactivity was significantly upregulated in many neuronal and glial populations (including the cortex, hippocampus and thalamus). HO-1 was also detected in macrophages/microglia within the infarct. In addition to widespread neuronal HO-2 labelling, HO-2 was also expressed in vascular endothelial cells. Inflammatory cells within the infarct of MCAO and HI animals were surprisingly immunoreactive for HO-2, but only HI animals had significantly elevated HO-2 protein expression in the ipsilateral hemisphere. This may be due to the presence of global hypoxia in the HI model which can upregulate vascular endothelial growth factor and subsequent proliferation of endothelial cells. This report of HO-2 protein expression upregulation following HI coupled with an increase in HO-1 immunoreactivity suggests that this response may be implicated in reducing cell death or repairing damage induced by cerebral ischemia.

Child disciplining practices in Kerala

This study was done to examine the type and severity of disciplinary practices adopted by parents in Kerala. 1668 mothers, aged 18-49, participated in face-to-face interviews as part of a cross-sectional, population-based survey covering rural, urban and coastal areas. One child from each family was randomly selected as the index child. The interview focused primarily on disciplinary practices. 62% of the mothers reported using severe verbal discipline and 50% of mothers reported using severe physical abuse. Results suggest a high prevalence of normative and abusive practices in the community with mothers playing a prime role in disciplining the child.

Predictors of birthweight--a cross sectional study

This study was conducted to find out the anthropometric, biosocial and obstetric predictors of birthweight in Kerala. The study sample consisted of 599 consecutive liveborn babies delivered at SAT Hospital, Medical College, Thiruvananthapuram and their mothers in November 2001. Details of maternal history, anthropometry, and biosocial and demographic factors were recorded. Birthweight was primary outcome variable. Multivariate analysis revealed that the biologically acceptable predictors of birthweight of a baby in our population are maternal height (P <0.001), parity (P < 0.001) gestational age (P < 0.001), pregnancy induced hypertension(P=0.05) and history of low birthweight in the previous pregnancy(P=0.05).

Monitoring of heavy metal partitioning in reef corals of Lakshadweep Archipelago, Indian Ocean

This paper focuses on the partitioning of trace metals in five selected coral species from Lakshadweep Archipelago, which remains as one of the least studied areas in the Indian Ocean. Based on the morphological features, selected coral species are classified as massive (Porites andrewsi), ramose or branching (Lobophyllia corymbosa, Acropora formosa and Psammocora contigua) and foliaceous (Montipora digitata). Relating trace metal concentrations with morphological features in skeleton, highest concentrations of all the trace metals (except Zn) were reported for the ramose type corals. In tissue, all the metals (essential as well as non essential) showed highest concentrations within the branching type corals. Irrespective of their growth characteristics/pattern, all species except P. contigua displayed higher concentrations of Pb, Ni, Mn and Cd within their skeleton compared to tissue which may exemplify a regulatory mechanism to avoid the build up of the concentrations of these metals in their bio-part, strikingly toxic metals like Cd and Pb. The concentrations of trace metals in the skeleton and tissues of these coral species were subjected to 3 way ANOVA based on non standardized original data and the results showed significant differences between metals and between species leading to high skeleton/ tissue - species interaction as well as skeleton/tissue - metal interaction. The significant values of student's t calculated are depicted in the form of Trellis diagrams.

Geochemical index of trace metals in the surficial sediments from the western continental shelf of India, Arabian Sea

The present study focuses on the determination and abundance of trace metals (viz. Cu, Ni, Zn, Cr, Co, Cd, Mn and Fe) in the surficial sediments of west coast of Arabian Sea along the Indian subcontinent. Sediment samples were collected from three transects along the western continental shelf of Arabian Sea. The enrichment of Fe and Mn in coastal oxic-sediments indicates the precipitation of these redox sensitive elements as Fe- and Mn-hydroxides and oxides, whereas the low Fe and Mn concentrations in the oxygen deficient sediments of deeper stations reflects the dissolution of their hydroxides and oxides. Concentrations of fairly redox insensitive trace metals like Cu, Ni, Zn, Cr and Cd (with the exceptions of Cr) showed higher values at nearshore sediments, then it decreased towards seaward and again showed a slight increase at oxygen minimum stations in all the three transects. This geochemical variability in their distributional characteristics is mainly associated with the extent to which the precipitation or dissolution of Fe- and Mn-oxides/hydroxides occur since the scavenging or releasing effects of Fe- and Mn-oxides/hydroxides act as significant 'sinks' or 'sources' of heavy metals. The change in wind pattern, coastal upwelling and increased productivity are also the reported factors which influence the biogeochemical cycling of trace metals in the surface sediments of west coast of India. Enrichment factor generally showed a high gradient accumulation from nearshore to shelf.

Cerebral hypoxia-ischemia and middle cerebral artery occlusion induce expression of the cannabinoid CB2 receptor in the brain

Until recently the cannabinoid CB2 receptor was believed to be absent from the central nervous system. In this study we have identified CB2 expressing cells that appear in the rat brain following stroke and hypoxic-ischemia. At 3 days following surgery CB2-positive macrophages, deriving from resident microglia and/or invading monocytes appear on the lesioned side of the brain. By day 7, a mixed population of CB2-positive cells is present. Microglia-derived macrophages are the key cells in the first stages of brain inflammation, and a pivotal step in the neurodegeneration that follows the acute stage of injury. Thus, CB2 may be important in the brain during injury, and in inflammatory neurodegenerative disorders. The presence of CB2-positive cells in the brain following stroke may provide a novel strategy for cannabinoid-mediated intervention into stroke induced neurodegeneration without the psychoactive effects of CB1 receptor stimulation.

(-)-Epigallocatechin gallate as an intervention for the acute treatment of cerebral ischemia

This study examined the neuroprotective effects and possible hepatotoxicity of (-)-epigallocatechin gallate (EGCG) in a rat model of transient focal cerebral ischemia. Male Sprague-Dawley rats (265-295 g) were treated with either 50 mg kg(-1) of EGCG or saline, i.p., immediately post-ischemia and every day thereafter, in a middle cerebral artery occlusion model of stroke. Sacrifice occurred 72 h post-ischemia and 2,3,5-triphenyltetrazolium chloride staining was used to quantify neuronal infarction. Hepatotoxicity was determined by taking blood samples for plasma alanine aminotransferase (ALT) activity. Spleen, kidney, liver and testes wet weights were also recorded. Total infarct volume was significantly (P<0.05) reduced in the EGCG-treated group as compared to controls. Analysis of the mean infarct area showed a significant (P<0.05) decrease in slices 6 and 7 in the EGCG-treated group. No significant differences were found in organ weights or ALT levels between treatment groups. Our findings, in part, validate and extend previous observations illustrating that 50 mg kg(-1), i.p. EGCG is non-toxic and neuroprotective. However, we also found that EGCG treatment appreciably increased (>50%) the number of animals that developed an intracerebral hemorrhage. We therefore conclude that 50 mg kg(-1) EGCG is not a viable intervention for the acute treatment of cerebral ischemia, as it is likely to increase the risk of intracerebral hemorrhaging.

Gene expression profiles associated with survival of individual rat dentate cells after endogenous corticosteroid deprivation

Removal of circulating corticosterone by adrenalectomy (ADX) leads to apoptosis after 3 days in a small population of rat dentate granule neurons, whereas most surrounding cells remain viable. Interestingly, a specific expression profile is triggered in surviving granule cells that may enhance their survival. Hippocampal slices prepared 1, 2 or 3 days after ADX or sham operation were stained ex vivo with Hoechst 33258, which serves to identify apoptotic neurons. After electrophysiological analysis, multiple gene expression in surviving individual granule cells was assessed by linear antisense RNA amplification and hybridization to slot blots containing various neuronal cDNAs. Hierarchical clustering and principal component analysis was performed on two physiological variables and 14 mRNA ratios from ADX cells from every time point. Our results indicate that surviving 3-day ADX granule cells display lower membrane capacitance, lower relative N-methyl-d-aspartate (NMDA) R1 mRNA expression and higher relative mineralocorticoid receptor (MR), alpha1A voltage-gated Ca-channel, Bcl-2 and NMDA R2C mRNA expression. Some 1- and 2-day ADX cells cluster with these 3-day survivors; therefore, one or more components of their mRNA expression profile may represent predictive markers for apoptosis resistance. The functional relevance of two candidate genes was tested by in vivo local over-expression in the same model system; of these, Bcl-2 conferred partial protection when induced shortly before ADX. Therefore, removal of corticosteroids triggers a specific gene expression profile in surviving dentate granule cells; key components of this profile may be associated with their survival.

Expression and role of sulfoglucuronyl (HNK-1) carbohydrate and its binding protein SBP-1 in developing rat cerebral cortex

Developmental expression of sulfoglucuronyl carbohydrate (SGC) and its binding protein, SBP-1 was studied in the rat cerebral cortex to understand their function. Between embryonic day (ED) 14-19, SBP-1 was strongly expressed in neurons of the ventricular zone and migrating neurons throughout the cortex. SBP-1 declined at birth and by postnatal day (PD) 3 only the latest arriving neurons in the most superficial segment of the cortical plate expressed SBP-1. Between ED 14-16, SGC was expressed in a thin row of glial cells near the ventricles and on their radial processes. Between ED 16-PD 3, SGC was not in neuronal cell soma, but was in neuronal plasma membranes and processes surrounding the neuronal perikarya. The expression of SGC declined similar to SBP-1 and both of them disappeared by PD 7. The expression of SBP-1 and SGC was chronologically coordinated with neuronal migration. SBP-1 was specifically expressed in immature neuronal nuclei and plasma membranes. SBP-1 and SGC were colocalized and were available for interaction with each other on neuronal cell membranes and processes. This was confirmed with isolated neurons in culture. As in vivo, the expression of SBP-1 in neurons declined with time in culture. The dissociated cortical neurons when plated on SBP-1 as a substratum produced extensive neuritic outgrowth. HNK-1, anti-SBP-1 antibodies and sulfoglucuronyl glycolipid, SGGL specifically and severely reduced neurite outgrowth. SBP-1-SGC interactions provide a potential mechanism for guidance and cell signaling, in the processes of neuronal migration and terminal differentiation.

Expression of sulfoglucuronyl (HNK-1) carbohydrate and its binding protein (SBP-1) in developing rat cerebellum

Sulfoglucuronyl carbohydrate (SGC) is expressed on several glycoproteins of the immunoglobulin superfamily of cell-adhesion molecules. Developmental expression of SGC and its binding protein, SBP-1, was studied in the rat cerebellum by immunocytochemistry to understand the function of SBP-1 and the significance of its interaction with SGC. During early postnatal development (postnatal day (PD) 3-10) SBP-1 was strongly expressed in the granule neurons of the external and internal granule cell layers (EGCL and IGCL). This expression declined by PD 15, and disappeared in the adult. Between PD 3 and 15, SGC was expressed in cellular processes surrounding the granule neurons in the IGCL, and it also declined and disappeared with development. SGC expression, however, continued in Purkinje cells and their dendrites in the molecular layer in adults. The expressions of SBP-1 and SGC were developmentally regulated and appeared to be chronologically co-ordinated with granule neuron migration from EGCL to IGCL. High magnification confocal microscopy showed that SBP-1 was primarily localized in nuclei and plasma membranes of granule neurons, whereas SGC in the IGCL was localized on neuronal plasma membranes, dendrites and glial processes, but not in cell soma. The relative localization of SBP and SGC was confirmed by cellular and subcellular markers in vivo and with dissociated cerebellar cells in culture. It is proposed that SBP-1 on plasma membranes of granule neurons interacts with SGC on the surrounding processes and membranes and this interaction could provide a potential mechanism for guidance and cell signaling, in the processes of granule neuron migration and differentiation.

Long-term exposure to high corticosterone levels attenuates serotonin responses in rat hippocampal CA1 neurons

Recent studies indicated that hyperactivity of the hypothalamo-pituitary-adrenal system is a considerable risk factor for the precipitation of affective disorders, most notably of major depression. The mechanism by which this hyperactivity eventually leads to clinical symptoms of depression is unknown. In the present animal study, we tested one possible mechanism, i.e., that long-term exposure to high corticosterone levels alters functional responses to serotonin in the hippocampus, an important area in the etiology of depression. Rats were injected daily for 3 weeks with a high dose of corticosterone; electrophysiological responses to serotonin were recorded intracellularly from CA1 pyramidal neurons in vitro. We observed that daily injections with corticosterone gradually attenuate the membrane hyperpolarization and resistance decrease mediated by serotonin-1A receptors. We next used single-cell antisense RNA amplification from identified CA1 pyramidal neurons to resolve whether the functional deficits in serotonin responsiveness are accompanied by decreased expression levels of the serotonin-1A receptor. It appeared that expression of serotonin-1A receptors in CA1 pyramidal cells is not altered; this result was supported by in situ hybridization. Expression of corticosteroid receptors in the same cells, particularly of the high-affinity mineralocorticoid receptor, was significantly reduced after long-term corticosterone treatment. The present findings indicate that prolonged elevation of the corticosteroid concentration, a possible causal factor for major depression in humans, gradually attenuates responsiveness to serotonin without necessarily decreasing serotonin-1A receptor mRNA levels in pyramidal neurons. These functional changes may occur by a posttranscriptional mechanism or by transcriptional regulation of genes other than the serotonin-1A receptor gene itself.

Expression of HNK-1 carbohydrate and its binding protein, SBP-1, in apposing cell surfaces in cerebral cortex and cerebellum

Sulfoglucuronyl carbohydrate is the terminal moiety of neolacto-oligosaccharides, expressed on several glycoproteins of the immunoglobulin superfamily involved in cell-cell recognition and on two glycolipids. Sulfoglucuronyl carbohydrate is temporally and spatially regulated in the developing nervous system. It appears to be involved in neural cell recognition and in cell adhesion processes through its interaction with specific proteins on cell surfaces. Previously we have characterized a specific sulfoglucuronyl carbohydrate-binding protein in rat brain. Sulfoglucuronyl carbohydrate binding protein-1 is structurally similar to a 30,000 mol. wt adhesive and neurite outgrowth promoting protein amphoterin [Rauvala and Pihlaskari (1987) J. biol. Chem. 262, p. 16,625]. The pattern of expression of sulfoglucuronyl carbohydrate binding protein-1 in developing rat nervous system was studied to understand the significance of its interaction with sulfoglucuronyl carbohydrate-bearing molecules. Biochemical analyses showed that the expression of sulfoglucuronyl carbohydrate binding protein-1 was developmentally regulated similarly to sulfoglucuronyl carbohydrate. Immunocytochemical localization of sulfoglucuronyl carbohydrate binding protein-1 and sulfoglucuronyl carbohydrate was performed by bright-field and fluorescent confocal laser scanning microscopy. In postnatal day 7 rat cerebellum, sulfoglucuronyl carbohydrate binding protein-1 was primarily associated with neurons of the external and internal granule cell layers. The sulfoglucuronyl carbohydrate binding protein-1 immunoreactivity was absent in Purkinje cell bodies and their dendrites in the molecular layer, as well as in Bergmann glial fibres and in white matter. In contrast, sulfoglucuronyl carbohydrate (reactive with HNK-1 antibody) was localized in processes surrounding granule neurons in the internal granule cell layer. Sulfoglucuronyl carbohydrate was also expressed in Purkinje neurons and their dendrites in the molecular layer and their axonal processes in the white matter. To a lesser extent Bergmann glial fibres were also positive for sulfoglucuronyl carbohydrate. In the cerebral cortex, at embryonic day 21, sulfoglucuronyl carbohydrate binding protein-1 was mainly observed in immature neurons of the cortical plate and subplate and dividing cells near the ventricular zone. Whereas, sulfoglucuronyl carbohydrate was strongly expressed in the fibres of the subplate and marginal zone. Sulfoglucuronyl carbohydrate was also found in the processes surrounding the sulfoglucuronyl carbohydrate binding protein-1-expressing neuronal cell bodies in the cortical plate and in ventricular zone. The specific localization of sulfoglucuronyl carbohydrate binding protein- in cerebellar granule neurons and neurons of the cerebral cortex was also confirmed by immunocytochemistry of the dissociated tissue cell cultures. The complementary localization of sulfoglucuronyl carbohydrate and sulfoglucuronyl carbohydrate binding protein-1, both in cerebral cortex and cerebellum, in apposing cellular structures indicate possible interaction between the two and signalling during the process of cell migration and arrest of migration.

Corticosteroid regulation of ion channel conductances and mRNA levels in individual hippocampal CA1 neurons

Overexposure to corticosteroid hormones is harmful to hippocampal neuronal integrity, likely by perturbation of calcium homeostasis. To identify molecular mechanisms at the single-cell level, we characterized mRNA expression corresponding to voltage- and ligand-gated Ca channels in individual dissociated CA1 neurons in response to long-term corticosterone (CORT) exposure. Predominant mineralocorticoid receptor occupation (ADC-LO group) resulted in low levels of P/Q- and L-type Ca channel mRNAs, high levels of GluR-2 versus GluR-1, and a high ratio of NMDAR-2A to NMDAR-2B mRNA. Corresponding alterations in protein expression were consistent with the restriction of Ca influx. In contrast, additional glucocorticoid receptor occupation (ADC-HI group) altered the expression of these mRNAs in a manner consistent with enhanced Ca influx; interestingly, qualitatively similar alterations were seen in control ADX neurons. Electrophysiological data from the same neurons indicate that Ca current amplitudes also are modulated by CORT, although on a shorter time scale. Finally, principal components analysis (PCA) suggests that neuronal AMPA and NMDA receptor composition may be regulated by MR and GR activation in a complex manner. Therefore, our data implicate molecular events by which CORT may regulate Ca influx into CA1 hippocampal neurons.

Characterization of a sulfoglucuronyl carbohydrate binding protein in the developing nervous system

The developmentally regulated and stage-specifically expressed HNK-1 carbohydrate found on sulfoglucuronylglycolipids (SGGLs) and certain glycoproteins has been proposed to be involved in neural cell adhesion and recognition processes through its interaction with protein "receptors." We have isolated and purified a approximately 30-kDa SGGL-binding protein (SBP-1) from neonatal rat brain. SBP-1 specifically bound to SGGLs and sulfatide both in solid-phase immunobinding and high-performance thin-layer chromatography-immunooverlay assays. N-terminal sequence analysis showed that SBP-1 is similar to an adhesive neurite outgrowth promoting protein amphoterin. Desulfation of SGGLs resulted in abolition of SBP-1 binding. However, chemical modification of glucuronic acid moiety by either esterification or reduction of the carboxyl group had no effect, suggesting requirement of the carbohydrate-linked sulfate group for SBP-1 binding. The binding of SBP-1 to SGGLs was specifically inhibited by HNK-1 antibody but not by other IgM antibodies. The binding of SBP-1 to sulfatide, however, was not inhibited by HNK-1 antibody. Heparin, fucoidan, and dextran sulfate (50K) also inhibited the binding of SBP-1 to SGGLs. During development of the rat cerebral cortex, the level of SBP-1 decreased after embryonic day 18 to an almost undetectable level by postnatal day 10, whereas in the cerebellum, the expression of SBP-1 was maximal at postnatal day 7. SBP-1 also bound specifically to the HNK-1 glycoproteins isolated from rat brain by HNK-1 immunoaffinity chromatography. Proteins without HNK-1 carbohydrate did not bind SBP-1. The binding to HNK-1 glycoproteins was inhibited by HNK-1 antibody, but not by other IgM antibodies, indicating that the binding was mediated through the HNK-1 carbohydrate moiety of the proteins. The interaction and coexpression of SBP-1 with SGGLs and HNK-1 glycoproteins, during the perinatal brain development, suggest a functional role for this protein.

Rostrocaudal expression of antibody HNK-1-reactive glycolipids in mouse cerebellum: relationship to developmental compartments and leaner mutation

Sulfoglucuronylglycolipids (SGGLs) and glycoproteins, reacting with monoclonal antibody HNK-1, are developmentally and spatially regulated in the mammalian cortex and cerebellum. It has been proposed that the HNK-1 carbohydrate epitope is involved in intercellular adhesion and cell-cell interactions. Biochemical analysis and immunocytochemical localization of SGGLs and other neolacto series glycolipids were studied in the leaner mutant mouse cerebellum, where a slow and progressive rostral to caudal degeneration occurs with a gradual loss of both granule cells and Purkinje cells. Biochemical analyses showed that SGGLs and other neolacto series of glycolipids were significantly decreased in the adult leaner cerebellum; however, HNK-1-reactive glycoproteins were not affected. By an immunocytochemical method which selectively localizes the lipid antigens, it is shown that SGGLs are primarily associated with Purkinje cell bodies and their dendrites in the molecular layer and in cerebellar nuclei where Purkinje cell axons terminate. At postnatal day 30 (P30), SGGL immunoreactivity (SGGL-ir) in the leaner cerebellum was reduced moderately compared to normal littermates, which correlated with the minimal degree of Purkinje cell degeneration at this age in leaner and with the biochemical data. At P67 and P90, the SGGL-ir was significantly more reduced in the leaner as Purkinje cell degeneration proceeded. There was a direct correlation between loss of Purkinje cells and SGGL-ir in the cerebellar molecular layer. In both normal and young leaner cerebella, the SGGL-ir in different lobules was not uniform; there were distinct rostrocaudal and mediolateral differences. SGGL-ir was markedly more intense in rostral than in caudal lobules in the vermis, the dividing line being the region immediately caudal to the primary fissure and rostral to the declival sulcus. In the lateral cerebellum, the SGGL-ir was less intense than in the vermis and the rostrocaudal difference was not as pronounced. There was also nonuniformity in the intensity of staining in different folia. The rostrocaudal as well as mediolateral differences in the intensity of SGGL-ir were confirmed independently by biochemical analysis. The differential phenotypic expression of SGGLs and the selective susceptibility to Purkinje cell death in leaner mutant are discussed in relation to the known embryologic and ontogenetic compartmentation of cerebellum.

Silver-binding nucleolar organizer region proteins as a possible prognostic indicator in oral submucous fibrosis

Silver-binding nucleolar organizer region proteins (AgNORs) were counted in sections from formalin-fixed, paraffin-embedded tissue blocks of oral submucous fibrosis (OSMF) and oral squamous cell carcinoma (SCC). Moderately advanced and advanced cases OSMF, and well-differentiated and poorly differentiated cases of SCC, were studied with respect to the relation between AgNOR counts and histologic grading. Normal oral mucosa collected from age- and sex-matched subjects constituted the control group. The pooled mean (+/- SD) AgNOR counts were as follows: normal mucosa, 2.50 +/- 0.52 (n = 5); moderately advanced OSMF, 5.24 +/- 1.23 (n = 10); advanced OSMF, 7.26 +/- 1.12 (n = 10); well-differentiated SCC, 8.29 +/- 1.47 (n = 5); and poorly differentiated SCC, 9.49 +/- 0.74 (n = 5). The pooled mean AgNOR counts in advanced OSMF were higher than in moderately advanced cases (t = 3.84; p < 0.005) and those in poorly differentiated SCC were higher than those of well-differentiated SCC, although the comparison was not significant in the latter (t = 1.63, p > 0.10). AgNOR counts could hold promise for predicting the biologic behavior of OSMF because this study demonstrated a correlation with clinical and histologic grading.

Prevalence of oral submucous fibrosis in the high natural radiation belt of Kerala, south India

Oral submucous fibrosis (OSMF) is a crippling disorder which is confined almost exclusively to the Indian subcontinent. Despite its association with a significantly increased risk of cancer, the etiology is still not clear. An epidemiological assessment showed 0.4% prevalence for OSMF in Kerala, South India, which is among the highest recorded. Recently the National Tumour Registry in Trivandrum reported the highest recorded site-specific incidence rate for oral cancer (ICD 140-145) in this area. The coastal belt of the Trivandrum and Quilon districts of Kerala has a very high natural radioactivity (over 1500 mR (387 microC) per year); about 500 mR (129 microC) per year is considered to be the maximum permissible dose for populations in general. An epidemiological survey in this area and in a comparable population (without exposure to high background radiation) as a control showed that the percentage prevalence of OSMF in the study area was 0.27 and in the control area 0.32. It appears highly improbable that the OSMF in the study area was induced by high background radiation.

Risk factors for cancer of the oesophagus in Kerala, India

A case-control study of oesophageal cancer was carried out in Trivandrum, Kerala, involving 267 cases and 895 controls. Risk factors studied in males were pan (betel)-tobacco chewing, bidi and cigarette smoking, drinking alcohol and taking snuff. Only pan-tobacco chewing was investigated in females as very few indulged in the other habits. Among males significant associations with higher risk were observed for bidi smoking (p less than 0.001), bidi plus cigarette smoking (p greater than 0.05) and drinking alcohol (p less than 0.001). While a significant effect of duration of pan-tobacco chewing (p less than 0.005) was observed in males, there was no significant trend, the risk first falling then rising as duration of use increased. This was partly due to confounding with smoking. No effect of pan-tobacco use was observed in females. A step-wise model was fitted, retaining only those risk factors which were significant when adjusted for other factors; the risk factors included were duration of pan-tobacco chewing, duration of bidi smoking, daily frequency of bidi and cigarette smoking and alcohol use (yes or no). An adjusted relative risk of 2.03 was observed for a pan-tobacco habit of more than 40 years' duration, of 4.70 for more than 20 years of bidi smoking, of 4.80 for more than 20 bidis/cigarettes per day, and of 2.33 for regular alcohol use (in each category relative to a baseline of those never indulging in the relevant habit).