Plants can talk: a new era in plant acoustics

Plants release chemical signals to interact with their environment when exposed to stress. Khait and colleagues unveiled that plants 'verbalize' stress by emitting airborne sounds. These can train machine learning models to identify plant stressors. This unlocks a new path in plant-environment interactions research with multiple possibilities for future applications.

Sound perception in plants: from ecological significance to molecular understanding

In addition to positive effects on plant growth and resilience, sound alerts plants of potential danger and aids in defense. Sound guides plants towards essential resources, like water, through phonotropic root growth. Sound also facilitates mutualistic interactions such as buzz pollination. Molecularly, sound induces Ca2+ signatures, K+ fluxes, and an increase in reactive oxygen species (ROS) levels in a mechanosensitive ion channel-dependent fashion. We review the two major open questions in the field of plant acoustics: (i) what is the ecological relevance of sound in plant life, and (ii) how is sound sensed and transduced to evoke a morphophysiological response? We highlight the clear need to combine the ecological and molecular perspectives for a more holistic approach to better understand plant behavior.

Arabidopsis plants overexpressing additional copies of heat shock protein Hsp101 showed high heat tolerance and endo-gene silencing

Hsp101 chaperone is vital for survival of plants under heat stress. We generated transgenic Arabidopsis thaliana (Arabidopsis) lines with extra copies of Hsp101 gene using diverse approaches. Arabidopsis plants transformed with rice Hsp101 cDNA driven by Arabidopsis Hsp101 promoter (IN lines) showed high heat tolerance while the plants transformed with rice Hsp101 cDNA driven by CaMV35S promoter (C lines) were like wild type plants in heat stress response. Transformation of Col-0 plants with 4633 bp Hsp101 genomic fragment (GF lines) from A. thaliana containing both its coding and the regulatory sequence resulted in mostly over-expressor (OX) lines and a few under-expressor (UX) lines of Hsp101. OX lines showed enhanced heat tolerance while the UX lines were overly heat sensitive. In UX lines, silencing of not only Hsp101 endo-gene was noted but also transcript of choline kinase (CK2) was silenced. Previous work established that in Arabidopsis, CK2 and Hsp101 are convergent gene pairs sharing a bidirectional promoter. The elevated AtHsp101 protein amount in most GF and IN lines was accompanied by lowered CK2 transcript levels under HS. We observed increased methylation of the promoter and gene sequence region in UX lines; however, methylation was lacking in OX lines.

The 5-formyl-tetrahydrofolate proteome links folates with C/N metabolism and reveals feedback regulation of folate biosynthesis

Folates are indispensable for plant development, but their molecular mode of action remains elusive. We synthesized a probe, "5-F-THF-Dayne," comprising 5-formyl-tetrahydrofolate (THF) coupled to a photoaffinity tag. Exploiting this probe in an affinity proteomics study in Arabidopsis thaliana, we retrieved 51 hits. Thirty interactions were independently validated with in vitro expressed proteins to bind 5-F-THF with high or low affinity. Interestingly, the interactors reveal associations beyond one-carbon metabolism, covering also connections to nitrogen (N) metabolism, carbohydrate metabolism/photosynthesis, and proteostasis. Two of the interactions, one with the folate biosynthetic enzyme DIHYDROFOLATE REDUCTASE-THYMIDYLATE SYNTHASE 1 (AtDHFR-TS1) and another with N metabolism-associated glutamine synthetase 1;4 (AtGLN1;4), were further characterized. In silico and experimental analyses revealed G35/K36 and E330 as key residues for the binding of 5-F-THF in AtDHFR-TS1 and AtGLN1;4, respectively. Site-directed mutagenesis of AtGLN1;4 E330, which co-localizes with the ATP-binding pocket, abolished 5-F-THF binding as well as AtGLN1;4 activity. Furthermore, 5-F-THF was noted to competitively inhibit the activities of AtDHFR-TS1 and AtGLN1;4. In summary, we demonstrated a regulatory role for 5-F-THF in N metabolism, revealed 5-F-THF-mediated feedback regulation of folate biosynthesis, and identified a total of 14 previously unknown high-affinity binding cellular targets of 5-F-THF. Together, this sets a landmark toward understanding the role of folates in plant development.

Critical Incidents in a Multidisciplinary Intensive Care Unit

We aimed to determine the type and frequency of critical incidents in a multidisciplinary intensive care unit, to determine outcomes consequent to these incidents and to devise corrective strategies.

Prospectively collected data on critical incidents during a 33-month period were analysed. In all, 1918 patients were admitted to the unit during the study period. Each incident was analysed in detail. A system-based corrective strategy was sought for and implemented as appropriate.

In these patients, 280 critical incidents were reported during the study period, resulting in 3.4 incidents per 100 patient days. Airway-related incidents were the most frequent (32.8%) followed by line-related (21.8%) and drug-related (15%) incidents. Thirty-two incidents (11.4%) led to adverse outcomes. There were four deaths that occurred as a direct consequence of or contributed to by the incident, all due to airway-related incidents. A major physiological change occurred in 3.6% of incidents, while 6.4% of incidents resulted in a minor physiological change. Critical incidents were common in our multidisciplinary ICU, although adverse outcomes were rare.

Drought-induced susceptibility for Cenangium ferruginosum leads to progression of Cenangium-dieback disease in Pinus koraiensis

Recently, the occurrence of "Cenangium-dieback" has been frequent and devastating. Cenangium-dieback is caused by an endophytic fungus Cenangium ferruginosum in stressed pine trees. Progression of the disease in terms of molecular interaction between host and pathogen is not well studied and there is a need to develop preventive strategies. Thus, we simulated disease conditions and studied the associated transcriptomics, metabolomics, and hormonal changes. Pinus koraiensis seedlings inoculated with C. ferruginosum were analyzed both under drought and well-watered conditions. Transcriptomic analysis suggested decreased expression of defense-related genes in C. ferruginosum-infected seedlings experiencing water-deficit. Further, metabolomic analysis indicated a decrease in the key antimicrobial terpenoids, flavonoids, and phenolic acids. Hormonal analysis revealed a drought-induced accumulation of abscisic acid and a corresponding decline in the defense-associated jasmonic acid levels. Pathogen-associated changes were also studied by treating C. ferruginosum with metabolic extracts from pine seedlings (with and without drought) and polyethylene glycol to simulate the effects of direct drought. From RNA sequencing and metabolomic analysis it was determined that drought did not directly induce pathogenicity of C. ferruginosum. Collectively, we propose that drought weakens pine immunity, which facilitates increased C. ferruginosum growth and results in conversion of the endophyte into the phytopathogen causing dieback.

Endophytic Trichoderma citrinoviride isolated from mountain-cultivated ginseng (Panax ginseng) has great potential as a biocontrol agent against ginseng pathogens

Background

Ginseng (Panax ginseng Meyer) is an invaluable medicinal plant containing various bioactive metabolites (e.g., ginsenosides). Owing to its long cultivation period, ginseng is vulnerable to various biotic constraints. Biological control using endophytes is an important alternative to chemical control.

Methods

In this study, endophytic Trichoderma citrinoviride PG87, isolated from mountain-cultivated ginseng, was evaluated for biocontrol activity against six major ginseng pathogens. T. citrinoviride exhibited antagonistic activity with mycoparasitism against all ginseng pathogens, with high endo-1,4-β-D-glucanase activity.

Results

T. citrinoviride inoculation significantly reduced the disease symptoms caused by Botrytis cinerea and Cylindrocarpon destructans and induced ginsenoside biosynthesis in ginseng plants. T. citrinoviride was formulated as dustable powder and granules. The formulated agents also exhibited significant biocontrol activity and induced ginsenosides production in the controlled environment and mountain area.

Conclusion

Our results revealed that T. citrinoviride has great potential as a biological control agent and elicitor of ginsenoside production.

Fungal endophytes inhabiting mountain-cultivated ginseng (Panax ginseng Meyer): Diversity and biocontrol activity against ginseng pathogens

Fungal endophytes isolated from mountain-cultivated ginseng (MCG, Panax ginseng Meyer) were explored for their diversity and biocontrol activity against ginseng pathogens (Alternaria panax, Botrytis cinerea, Cylindrocarpon destructans, Pythium sp. and Rhizoctonia solani). A total of 1,300 isolates were isolated from three tissues (root, stem and leaf) from MCGs grown in 24 different geographic locations in Korea. In total, 129 different fungal isolates were authenticated by molecular identification based on internal transcribed spacer (ITS) sequences. The fungal endophytes belonged to Ascomycota (81.7%), Basidiomycota (7.08%), Zygomycota (10%) and Unknown (1.15%), with 59 genera. Analysis of diversity indices across sampling sites suggested species abundance as a function of geographical and environmental factors of the locations. Shannon diversity index and richness in the different tissues revealed that root tissues are colonized more than stem and leaf tissues, and also certain fungal endophytes are tissue specific. Assessment of the ethyl acetate extracts from 129 fungal isolates for their biocontrol activity against 5 ginseng pathogens revealed that Trichoderma polysporum produces the antimcriobial metabolite against all the pathogens. This result indicates the promise of its potential usage as a biocontrol agent.

Exposure to Sound Vibrations Lead to Transcriptomic, Proteomic and Hormonal Changes in Arabidopsis

Sound vibration (SV) is considered as an external mechanical force that modulates plant growth and development like other mechanical stimuli (e.g., wind, rain, touch and vibration). A number of previous and recent studies reported developmental responses in plants tailored against SV of varied frequencies. This strongly suggests the existence of sophisticated molecular mechanisms for SV perception and signal transduction. Despite this there exists a huge gap in our understanding regarding the SV-mediated molecular alterations, which is a prerequisite to gain insight into SV-mediated plant development. Herein, we investigated the global gene expression changes in Arabidopsis thaliana upon treatment with five different single frequencies of SV at constant amplitude for 1 h. As a next step, we also studied the SV-mediated proteomic changes in Arabidopsis. Data suggested that like other stimuli, SV also activated signature cellular events, for example, scavenging of reactive oxygen species (ROS), alteration of primary metabolism, and hormonal signaling. Phytohormonal analysis indicated that SV-mediated responses were, in part, modulated by specific alterations in phytohormone levels; especially salicylic acid (SA). Notably, several touch regulated genes were also up-regulated by SV treatment suggesting a possible molecular crosstalk among the two mechanical stimuli, sound and touch. Overall, these results provide a molecular basis to SV triggered global transcriptomic, proteomic and hormonal changes in plant.

Constitutive over-expression of rice ClpD1 protein enhances tolerance to salt and desiccation stresses in transgenic Arabidopsis plants

Caseinolytic proteases (Clps) perform the important role of removing protein aggregates from cells, which can otherwise prove to be highly toxic. ClpD system is a two-component protease complex composed of a regulatory ATPase module ClpD and a proteolytic component ClpP. Under desiccation stress condition, rice ClpD1 (OsClpD1) gene encoding for the regulatory subunit, was represented by four variant transcripts differing mainly in the expanse of their N-terminal amino acids. These transcripts were expressed in a differential manner in response to salt, mannitol and polyethylene glycol stresses in rice. Purified OsClpD1.3 protein exhibited intrinsic chaperone activity, shown using citrate synthase as substrate. Arabidopsis (Col-0) plants over-expressing OsClpD1.3 open reading frame downstream to CaMV35S promoter (ClpD1.3 plants) showed higher tolerance to salt and desiccation stresses as compared to wild type plants. ClpD1.3 seedlings also showed enhanced growth during the early stages of seed germination under unstressed, control conditions. The free proline levels and starch breakdown activities were higher in the ClpD1.3 seedlings as compared to the wild type Arabidopsis seedlings. It thus emerges that increasing the potential of ClpD1 chaperoning activity may be of advantage in protection against abiotic stresses.

Plant acoustics: in the search of a sound mechanism for sound signaling in plants

Being sessile, plants continuously deal with their dynamic and complex surroundings, identifying important cues and reacting with appropriate responses. Consequently, the sensitivity of plants has evolved to perceive a myriad of external stimuli, which ultimately ensures their successful survival. Research over past centuries has established that plants respond to environmental factors such as light, temperature, moisture, and mechanical perturbations (e.g. wind, rain, touch, etc.) by suitably modulating their growth and development. However, sound vibrations (SVs) as a stimulus have only started receiving attention relatively recently. SVs have been shown to increase the yields of several crops and strengthen plant immunity against pathogens. These vibrations can also prime the plants so as to make them more tolerant to impending drought. Plants can recognize the chewing sounds of insect larvae and the buzz of a pollinating bee, and respond accordingly. It is thus plausible that SVs may serve as a long-range stimulus that evokes ecologically relevant signaling mechanisms in plants. Studies have suggested that SVs increase the transcription of certain genes, soluble protein content, and support enhanced growth and development in plants. At the cellular level, SVs can change the secondary structure of plasma membrane proteins, affect microfilament rearrangements, produce Ca(2+) signatures, cause increases in protein kinases, protective enzymes, peroxidases, antioxidant enzymes, amylase, H(+)-ATPase / K(+) channel activities, and enhance levels of polyamines, soluble sugars and auxin. In this paper, we propose a signaling model to account for the molecular episodes that SVs induce within the cell, and in so doing we uncover a number of interesting questions that need to be addressed by future research in plant acoustics.

Characterization of 5'UTR of rice ClpB-C/Hsp100 gene: evidence of its involvement in post-transcriptional regulation

Rice (Oryza sativa) ClpB-C (OsClpB-C) protein is expressed upon heat stress in vegetative tissues and constitutively in seeds. We produced stably transformed Arabidopsis plants carrying β-glucuronidase (Gus) reporter gene downstream to 1-kb OsClpB-C promoter (1kbPro plants). In the 1kbPro plants, expression of Gus transcript and protein followed the expression pattern of OsClpB-C gene in rice plants, i.e., heat induced in vegetative tissues and constitutive in seeds. Next, we produced transgenic Arabidopsis plants containing Gus downstream to 862-bp fragment of OsClpB-C promoter [lacking 138 nucleotides from 3' end of the 5'untranslated region (5'UTR); ∆UTR plants). In ∆UTR plants, Gus transcript was expressed in heat-inducible manner, but strikingly, Gus protein levels were negligible after heat treatment. However, Gus protein was expressed in ∆UTR seedlings at levels comparable to 1kbPro seedlings when recovery treatment of 22 °C/2 h was given post heat stress (38 °C/15 min). This suggests that 5'UTR of OsClpB-C gene is involved in its post-transcriptional regulation and is an obligate requirement for protein expression during persistent heat stress. Furthermore, the Gus transcript levels were higher in the polysomal RNA fraction in heat-stressed seedlings of 1kbPro plants as compared to ∆UTR plants, indicating that 5'UTR aids in assembly of ribosomes onto the Gus transcript during heat stress. Unlike the case of seedlings, Gus protein was formed constitutively in ∆UTR seeds at levels comparable to 1kbPro seeds. Hence, the function of 5'UTR of OsClpB-C is dispensable for expression in seeds.

Constitutive over-expression of rice chymotrypsin protease inhibitor gene OCPI2 results in enhanced growth, salinity and osmotic stress tolerance of the transgenic Arabidopsis plants

Protease inhibitors are involved primarily in defense against pathogens. In recent years, these proteins have also been widely implicated in response of plants to diverse abiotic stresses. Rice chymotrypsin protease inhibitor gene OCPI2 is highly induced under salt and osmotic stresses. The construct containing the complete coding sequence of OCPI2 cloned downstream to CaMV35S promoter was transformed in Arabidopsis and single copy, homozygous transgenic lines were produced. The transgenic plants exhibited significantly enhanced tolerance to NaCl, PEG and mannitol stress as compared to wild type plants. Importantly, the vegetative and reproductive growth of transgenic plants under unstressed, control conditions was also enhanced: transgenic plants were more vigorous than wild type, resulting into higher yield in terms of silique number. The RWC values and membrane stability index of transgenic in comparison to wild type plants was higher. Higher proline content was observed in the AtOCPI2 lines, which was associated with higher transcript expression of pyrroline-5-carboxylate synthase and lowered levels of proline dehydrogenase genes. The chymotrypsin protease activities were lower in the transgenic as against wild type plants, under both unstressed, control as well as stressed conditions. It thus appears that rice chymotrypsin protease inhibitor gene OCPI2 is a useful candidate gene for genetic improvement of plants against salt and osmotic stress.

Intergenic sequence between Arabidopsis caseinolytic protease B-cytoplasmic/heat shock protein100 and choline kinase genes functions as a heat-inducible bidirectional promoter

In Arabidopsis (Arabidopsis thaliana), the At1g74310 locus encodes for caseinolytic protease B-cytoplasmic (ClpB-C)/heat shock protein100 protein (AtClpB-C), which is critical for the acquisition of thermotolerance, and At1g74320 encodes for choline kinase (AtCK2) that catalyzes the first reaction in the Kennedy pathway for phosphatidylcholine biosynthesis. Previous work has established that the knockout mutants of these genes display heat-sensitive phenotypes. While analyzing the AtClpB-C promoter and upstream genomic regions in this study, we noted that AtClpB-C and AtCK2 genes are head-to-head oriented on chromosome 1 of the Arabidopsis genome. Expression analysis showed that transcripts of these genes are rapidly induced in response to heat stress treatment. In stably transformed Arabidopsis plants harboring this intergenic sequence between head-to-head oriented green fluorescent protein and β-glucuronidase reporter genes, both transcripts and proteins of the two reporters were up-regulated upon heat stress. Four heat shock elements were noted in the intergenic region by in silico analysis. In the homozygous transfer DNA insertion mutant Salk_014505, 4,393-bp transfer DNA is inserted at position -517 upstream of ATG of the AtClpB-C gene. As a result, AtCk2 loses proximity to three of the four heat shock elements in the mutant line. Heat-inducible expression of the AtCK2 transcript was completely lost, whereas the expression of AtClpB-C was not affected in the mutant plants. Our results suggest that the 1,329-bp intergenic fragment functions as a heat-inducible bidirectional promoter and the region governing the heat inducibility is possibly shared between the two genes. We propose a model in which AtClpB-C shares its regulatory region with heat-induced choline kinase, which has a possible role in heat signaling.

Aspergillus colonization in hydatid cyst: Addition of a case

Aspergillus is a common saprophytic fungus that causes invasive or non-invasive disease in humans. It commonly colonizes pre-existing lung cavities. It has been earlier reported to coexist in previously operated or ruptured hydatid cysts. However there have been only few case reports of its occurrence in previously unoperated cysts in immunocompetent hosts. The present case adds to this category.

OsHsfA2c and OsHsfB4b are involved in the transcriptional regulation of cytoplasmic OsClpB (Hsp100) gene in rice (Oryza sativa L.)

ClpB-cytoplasmic (ClpB-cyt)/Hsp100 is an important chaperone protein in rice. Cellular expression of OsClpB-cyt transcript is governed by heat stress, metal stress, and developmental cues. Transgenic rice plants produced with 2 kb OsClpB-cyt promoter driving Gus reporter gene showed heat- and metal-regulated Gus expression in vegetative tissues and constitutive Gus expression in calli, flowering tissues, and embryonal half of seeds. Rice seedlings regenerated with OsClpB-cyt promoter fragment with deletion of its canonical heat shock element sequence (HSE(-273 to -280)) showed not only heat shock inducibility of Gus transcript/protein but also constitutive expression of Gus in vegetative tissues. It thus emerges that the only classical HSE present in OsClpB-cyt promoter is involved in repressing expression of OsClpB-cyt transcript under unstressed control conditions. Yeast one-hybrid assays suggested that OsHsfA2c specifically interacts with OsClpB-cyt promoter. OsHsfA2c also showed binding with OsClpB-cyt and OsHsfB4b showed binding with OsClpB-cyt; notably, interaction of OsHsfB4b was seen for all three OsClpB/Hsp100 protein isoforms (i.e., ClpB-cytoplasmic, ClpB-mitochondrial, and ClpB-chloroplastic). Furthermore, OsHsfB4b showed interaction with OsHsfA2c. This study suggests that OsHsfA2c may play a role as transcriptional activator and that OsHsfB4b is an important part of this heat shock responsive circuitry.

Current status of malaria control

Malaria caused by Plasmodium parasites kills approximately 1-3 million people and causes disease in 300-500 million people annually throughout the world. The current approaches to curtail this disease include vector control, vaccination, immunotherapy and chemotherapy. The vector control is achieved by reducing vector density, interrupting their life cycle, and creating a barrier between the human host and mosquitoes. A number of vaccine candidates are being clinically tried and R&D effort in this direction is coming in a big way. Currently there are only limited safe drugs for the treatment of this disease, however, reports of emerging resistance against existing drugs warrant the introduction of new drugs, which are unlikely to come from pharmaceutical industries because of limited commercial opportunities. One of the most important current approaches to develop new drugs involves the synthesis of chemical libraries and evaluate them against most validated biochemical targets of malarial parasite. Although a number of such targets in antimalarial drug development are known today, yet only validated and selective biochemical targets including mitochondrial transport, glycolic pathway, folate pathway, proteases and heme metabolism, apicoplast metabolism, glycophospatidyl inositol, lipid metabolism (glycerophospholipids), peptidyl deformylase and oxidative stress in parasite-infected erythrocytes have been discussed here. The well known antimalarial drugs and different drug combinations for the treatment of malaria are also briefly reviewed. A survey of the recently discovered new molecules active against malaria has also been narrated. Lastly, the future of malaria chemotherapy and new directions emerging from literature has been elucidated.

Leishmanicidal activity of phenylene bridged C2 symmetric glycosyl ureides

A number of phenylene bridged C2 symmetric glycosyl uerides with ester (3a-f), alcohol (4a-c) and acid (5a-d) functionalities were prepared by addition of glycosyl amino esters with phenyl diisocyanates and their further reaction with LiAlH(4) or hydrolysis with LiOH. All the compounds were screened for their in vitro and in vivo antileishmanial activity. Most of the compounds exhibited good activity while two of the compounds 3e and 3f reduced the clinical dose of standard drug SSG.

Synthesis of glycosylated β-Amino hydroxamates as new class of antimalarials

Glycosylated beta-amino acids (3-18, 38, 39), obtained by hydrolysis of glycosylated beta-amino esters on reaction with hydroxylamine hydrochloride in presence of DIC/DCC afforded glycosyl beta-amino hydroxamates (19-34, 40, 41) in fair to good yields. Compounds (19-34, 40, 41) were screened against human malarial parasite Plasmodium falciparum in vitro for their schizontocidal activity. Compounds (19, 24, 26, 28, 40 and 41) exhibited good activity at 2 microg/mL concentrations.

Synthesis and bioevaluation of glycosyl ureas as alpha-glucosidase inhibitors and their effect on mycobacterium

Glycosyl amino esters (2-13) on reaction with different isocyanates resulted in quantitative conversion to glycosyl ureas (14--32). Few of the selected ureas (15-20, 22-28, 30 and 32) on cyclative amidation with DBU/TBAB/4 A MS gave respective dihydropyrimidinones in fair to good yields (33-47). The compounds were screened for alpha-glucosidase inhibitory activity and two (19 and 23) of them showed strong inhibition against rat intestinal alpha-glucosidase. The compounds were also screened against Mycobacterium aurum, however, only one (19) of them exhibited marginal antitubercular activity.

DBU-assisted cyclorelease elimination: combinatorial synthesis and gamma-glutamyl cysteine synthetase and glutathione-S-transeferase modulatory effect of C-nucleoside analogs

A combinatorial library of 60C- nucleoside analogs was synthesized by sequential coupling of building blocks followed by cyclative cleavage with DBU in an efficient manner. Only DMSO soluble compounds were tested for their modulatory effect against filarial gamma-glutamyl cysteine synthetase (gamma-GCase) and glutathione-S-transeferases (GSTs). Several compounds were found to be weak inhibitors of filarial gamma-GCase, whereas, most of them stimulated filarial GSTs.

Cultural variation in hemifacial asymmetry of emotion expressions

Photographs of hemifacial composites (left-left, right-right and normal presentation, right-left) of these cultures (Japanese, Oriental Indian and North American) displaying six emotions (happy, sad, fear, anger, surprise, disgust) and a neutral state were administered successively (one by one) as well as simultaneously (three hemifacial photographs of an expression at a time) to observers for judgment on a 5-point scale in terms of distinctiveness of expression. Observers' judgments were treated with a culture of expressor x sex of expressor x facial presentation x emotion category mixed factorial ANOVA. Cultures did not vary for their distinctiveness of facial expressions, suggesting universality in this respect. Culture-specificity was, however, observed with respect to hemifacial asymmetry and valence of emotion expressions: (1) Japanese showed a right hemifacial bias for positive and left hemifacial bias for negative emotions; Indians and North Americans showed left hemifacial bias for all emotions, and (2) negative emotion expressions were least distinctly identifiable in Japanese faces followed by Indian and North American faces.

Tumour thickness and relationship to locoregional failure in cancer of the buccal mucosa

AIMS

The TNM system is the main parameter in treatment planning and the prediction of survival in oral cancer. Here, we investigate the role of tumour thickness as a predictor of locoregional failure and survival in node-negative patients.

METHODS

We studied 176 node-negative and early stage gingivo-buccal squamous cell carcinoma patients retrospectively. Clinico-pathological factors investigated for tumour failure prediction were: T stage; tumour differentiation; tumour thickness; and treatment. Tumour thickness was measured using an ocular micrometer.

RESULTS

Locoregional tumour failure was found in 34% of cases (60 of 176). Tumour differentiation was found not to be statistically significant in predicting tumour failure. The covariates predicting tumour failure were T stage (P<0.05); type of surgical treatment (P<0.05); and tumour thickness (P<0.001). The mean tumour thickness found was 4 mm. Tumours 4 mm in thickness behaved similarly in all three stages and those >4 mm had a higher rate of lymph-node metastasis. No distant metastasis was found in this series.

CONCLUSION

Tumour thickness was found to be an accurate predictor of locoregional failure in early stage cancer of the buccal mucosa.

Pectoralis major rib osteomyo cutaneous flap in primary mandibular reconstruction in floor of the mouth cancer

We report pectoralis major rib osteo myocutaneous flap in reconstruction of cancer floor of the mouth in 8 cases. We have discussed it's advantages in country like ours over the micro vascular graft. The rib (Vascularised bone graft) incorporated in this flap gives ideal support for mandibular arch reconstruction.

Reconstruction of alae of the nose and angle of the mouth with naso labial flap

Naso labial flap is an ideal flap for reconstruction of alae of the nose and angle of the mouth after excision for malignancy. Due to inconspicuous deformity of the donor area it is ideal in old age. We report our experience in 7 cases of basal cell carcinoma of the alae of the nose and 11 cases of carcinoma angle of the mouth.

Post-operative radiotherapy in carcinoma of buccal mucosa, a prospective randomized trial

Squamous cell carcinoma of the buccal mucosa is a common cancer in India. We are referred a large number of locally advanced lesions where curative surgery is still possible. The objective of this study is to determine the role of post-operative radiotherapy in enhancing disease-free survival. Patients with stages III and IV cancer of the buccal mucosa potentially curable by surgery were randomized to surgery only or post-operative radiotherapy. Patients were followed up for 3 years. The clinico-pathological features in both arms were comparable. Disease-free survival at the end of the study was found to be 38% and 68% (P<0.005) respectively. Post-operative radiotherapy was thus seen to improve disease-free survival in squamous cell carcinoma of the buccal mucosa.

Management of carcinoma anal canal with combination chemotherapy and concurrent radiotherapy

Results of 21 cases of squamous cell carcinoma of anal canal treated by continuous infusion of 5-fluorouracil 1000 mg/sqm for 4 days and mitomycin-C 15 mg/sqm on 1st day by i.v. route with concurrent external beam radiotherapy of 42 Gy from 1st day of chemotherapy were analysed. Out of 21 patients, 16(76.19%) achieved complete remission, 3 (14.28%) partial remission and 2 (9.52%) cases did not respond at all. On follow-up, 7 (33.33%) histopathological positive cases needed abdominoperineal resection with good recovery. After 2 years of follow-up 14 (66.67%) cases were free from the disease and 3 (14.28%) were alive with the disease. The median duration of follow-up was 36 months.

Study of tumour ploidy in early stages of buccal mucosa cancer

The purpose of this study was to determine whether a tumour's DNA content is a prognostic factor in screening out the biologically aggressive varieties of early buccal mucosa cancer. Seventy-eight cases of early squamous cell carcinoma of the buccal mucosa were studied, including 73 with aneuploid and diploid tumours. T1 and T2 tumours, pathological differentiation, vascular and perineural invasion, and the recurrence and disease-free survival rate in relation to aneuploid and diploid content were ascertained. The recurrence rate in aneuploid tumours is 72%, whereas in diploid tumours it is 6% (P<0.001). A Cox regression analysis demonstrated that tumour ploidy was a prognostic factor in disease-free survival, independent of other clinico-pathological characteristics examined. Aneuploidy is the most accurate predictor of biological aggressiveness of cancer of the buccal mucose. Aneuploid early buccal mucosa cancers should be treated by multimodal therapy to achieve a cure.

Balloon mitral commissurotomy: an intraoperative assessment

OBJECTIVE

Advances in balloon catheter technology have revolutionized the management of obstructive cardiovascular diseases. For lesions like mitral stenosis, balloon commissurotomy has emerged as an alternative to surgical relief showing definite functional benefits in a few clinical trials, albeit with variable results. Such variability necessitated objective evaluation of the efficacy of balloon mitral commissurotomy.

METHODS

The balloon mitral commissurotomy was carried out in 11 patients suffering from isolated mitral stenosis, under vision in a surgical setting. All patients were in NYHA class III/IV. Initially single balloon was used for mitral commissurotomy followed by double balloon, before completing the mitral valvotomy with surgical instruments whenever required. The commissural split was measured by firmly stretching the two commissures using nerve hooks and measuring the distance between the two hooks with the help of a caliper. Assessment of balloon dilation was made by calculating exact percentage of residual commissural split following balloon dilation as compared with completed mitral valvotomy. The exact percentage of commissural split was thus obtained by subtracting residual commissural split following balloon dilation from commissural split obtained after surgical open mitral valvotomy.

RESULTS

Complete commissurotomy using the balloon technique was possible in two (18.2%) patients. In the remaining nine (81.8%) patients, balloon expansion provided only 50% to 80% of commissural split and required instrumental completion with good results.

CONCLUSIONS

Balloon mitral commissurotomy, by virtue of its circumferential force, helps to develop a good cleavage and attains good hemodynamic improvement which may be life saving in critical mitral stenosis in selected group of patients with pliable mitral leaflets and minimal subvalvular pathology.

Blood conservation in valve surgery

Blood utilization in 40 patients undergoing elective valve surgery was prospectively studied. The patients had valvular lesions of rheumatic origin with a mean age of 29.1 years and a mean preoperative hematocrit of 35.23 +/- 4.16. Blood was removed from all patients after induction of anesthesia and reinfused after bypass (mean 365.12 +/- 66.96 ml). Membrane oxygenator was used in all the patients. All discard suction was routed through a regionally heparinised collecting and processing system, and the resulting red cell concentrate was transfused. At the conclusion of bypass, all blood remaining in the pump oxygenator was also processed by cell saver and used for subsequent reinfusion. Normovolemic anemia was accepted in hemodynamically stable patients. Thirty two patients (80%) received no bank blood or blood products during their entire hospital course. A total of twelve units of whole blood was transfused into eight patients.

Surgical management of cardiac myxomas

Cardiac myxomas are rare cardiac lesions, though they are the commonest tumours of the heart. Seventeen cases of cardiac myxomas have been operated during the last one decade. Exertional dyspnoea, palpitation and chest pain were the main presenting symptoms. Echocardiographic assessment was the only definitive diagnostic investigation required prior to surgery. Early surgical excision was planned in all the cases. Irrespective of the exposure techniques, removal of the tumour with wide excision of its base was practised. There was one early death due to low cardiac output in a patient brought in a shock like state. Follow up study has revealed 14 patients in NYHA class I and two patients are having class II symptoms. Periodic echocardiographic follow up study has not revealed any recurrence till date. It is concluded that an early diagnosis and surgery gives excellent long term results in these cases.