Marine estuaries act as better sink for greenhouse gases during winter in undisturbed mangrove than degraded ones in Sundarban, India

The estuaries provide the key pathway for travelling carbon across the land-ocean interfaces and behave as both source and sink of greenhouse gases (GHGs) in water-atmosphere systems. The sink-source characteristics of estuaries for GHGs vary spatially. The primary driving factors are adjacent ecologies (agriculture, aquaculture, etc.) and proximities to the sea. To study the sink-source characteristics of estuaries for GHGs (methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2)), the water samples were collected from 53 different locations in the estuaries for estimation of dissolved GHGs concentration and air-water GHGs exchanges. The locations represent five zones (Zone I, II, III, IV and V) based on the type and degradation status of mangroves (degraded and undisturbed), anthropogenic activities, and distance from the sea. Zone I, III, V represents to the degraded mangroves far from sea, whereas, Zone II, IV surrounded by undisturbed mangroves and nearer to sea. The average dissolved CH4 concentrations were higher in the estuaries which were adjacent to degraded mangroves (154.4 nmol L-1) than undisturbed mangroves (81.7 nmol L-1). Further, the average dissolved N2O concentrations were 48% higher in the estuaries nearer to degraded mangroves than that of undisturbed ones. Among the degraded mangrove sites, the dissolved CO2 concentrations were higher at Zone I (30.1 μmol L-1) followed by Zone III and IV, whereas in undisturbed sites, it was higher in Zone IV (22.3 μmol L-1) than Zone II (17.6 μmol L-1). Among the 53 locations, 36, 51 and 33 locations acted as a sink (negative value of exchanges) for CH4, N2O and CO2, respectively. The higher sink potential for CH4 was recorded to those estuaries adjacent to undisturbed mangroves (-791.69 μmol m-2 d-1) than the degraded ones (-23.18 μmol m-2 d-1). Similarly, the average air-water N2O and CO2 exchanges were more negative in the estuaries which were nearer to undisturbed mangroves indicating higher sink potential. The pH, and salinity of the estuary water were negatively correlated with air-water CH4 and N2O exchanges, whereas those were positively correlated with CO2 exchanges. Significantly lower dissolved GHGs and air-water GHGs exchange was observed in the estuaries adjacent to the undisturbed mangrove as compared to the degraded mangrove. The reason behind higher sink behaviours of estuaries nearer to undisturbed mangroves are higher intrusion of seawater, less nutrient availability, higher salinity, low carbon contents and alkaline pH compared to estuaries adjacent to degraded mangroves and far from sea.

Rubber expansion and age-class mapping in the state of Tripura (India) 1990-2021 using multi-year and multi-sensor data

The present study focuses on the spread of rubber monoculture in the state of Tripura during past three decades (1990-2021) in the northeast region of India which is known for its rich biodiversity, shifting cultivation, and extensive forest dynamics. Earth observation (EO) data of seven time periods from Landsat missions (1990, 1995, 2000, 2004, and 2009) and Sentinel-2 (2016 and 2021) were the main source for mapping and were supplemented with MODIS-EVI temporal spectral profiles, GEDI-derived vegetation heights (2019), and Google Earth high-resolution historical images for additional cues to support discrimination, mapping, and accuracy assessment. The methodology for rubber used its unique phenology from spectral-temporal profile and multi-year comparison of patches and their dynamics for age-class mapping. The results indicate that in the state of Tripura (geographic area 1.08 Mha), the area under rubber increased from 0.3% in 1990 to 8.9% of the geographic area in 2021. The overall classification accuracy for the maps created for the years 1990, 1995, 2000, 2004, 2009, 2016, and 2021 was 84.2%, 83.9%, 84.8%, 88.0%, 86.0%, 86.7%, and 89.5%, respectively. New areas under rubber originated from various land cover classes including open forests, shifting cultivation lands, and scrub. Recent expansion has resulted in 84.3% of rubber plantations under the 10-year age class. Implications of this transformation of the natural landscape, biodiversity and biomass, and carbon pool assessment are discussed.

Efficacy of Spirulina 500 mg vs Triamcinolone Acetonide 0.1% for the Treatment of Oral Lichen Planus: A Randomized Clinical Trial

AIM

The present study aimed at evaluating the efficacy of spirulina 500 mg in reducing the burning sensation and lesion size in oral lichen planus (OLP).

MATERIALS AND METHODS

A total of 60 subjects who attended the oral medicine specialty clinic with histopathologically confirmed OLP and having symptoms of burning sensation were recruited for the study. They were randomly divided into two groups: group A (30) subjects were prescribed Spirulina 500 mg twice daily along with only a week application of topical triamcinolone acetonide 0.1% thrice daily; group B subjects were prescribed topical triamcinolone acetonide 0.1% alone thrice daily for 8 weeks. Both the groups were followed up posttreatment monthly for three consecutive months.

RESULTS

Data were recorded, and statistical analysis by using ANOVA one-way test, and Chi-square test were performed, which showed statistically significant p-value (<0.005) for the parameters "burning sensation" and "size of the lesion". When compared between groups, group A showed a favorable outcome of the intervention.

CONCLUSION

Spirulina 500 mg supplementation twice daily could be effective adjunct therapy with steroids to treat OLP.

CLINICAL SIGNIFICANCE

This research allowed us to delve into spirulina as one of the treatment modalities for OLP. Further studies are needed as it is a rich source of proteins and vitamins and demonstrates potent anti-inflammatory, immunomodulatory, and antioxidant actions.

Seasonal fluctuation in three mode of greenhouse gases emission in relation to soil labile carbon pools in degraded mangrove, Sundarban, India

Tropical mangrove represents one of the most threatened ecosystems despite their huge contribution to ecosystem services, carbon (C) sequestration and climate change mitigation. Understanding the system in light of seasonal fluctuations on greenhouse gases (GHGs) emissions due to human interferences and the tidal effect is important for devising site-specific real-time climate change mitigation strategies. In order to capture the seasonal variations, the three modes of transport of GHGs through pneumatophore, ebullition as bubbles and water-soluble diffusion was quantified. The three unique techniques for the gas collection were used to estimate the GHGs [methane (CH₄), nitrous oxide (N₂O) and carbon dioxide (CO₂)] emission, at three degraded-mangrove sites in Sundarban, India. We identified three degraded mangrove ecologies based on the remote sensing data of 1930 and 2013 (mangrove-covered area in Sundarban; 2387, 2136 km², respectively). Samples were collected and analyzed for four seasons [winter (November-January), summer (February-April), pre-monsoon (May-June) and monsoon (July-October)], at three representative sites (Sadhupur, Dayapur, and Pakhiralaya). Monsoonal CH₄ and CO₂ fluxes (0.353 ± 0.026 and 64.5 ± 6.1 mmol m^-2 d^-1, respectively) were higher than winter and summer. However, the soil labile C pools showed the opposite trend i.e. more in summer followed by winter and monsoon. In contrast, the N₂O fluxes were more during summer (54.2 ± 3.2 μmol m^-2 d^-1). The stagnant water had higher dissolved GHGs concentration compared to tidewater due to less salinity and a long time of stagnation. The mode of transport of GHGs through pneumatophore, ebullition, and water-soluble diffusion was also significantly varied with seasons, soil‑carbon status and tidewater intrusion. Therefore, seasonal fluctuations of GHGs emission and tidal effect must be considered along with soil labile C pools for GHG-C budgeting and climate change mitigation in the mangrove ecosystem.

Advances in terrestrial and ocean dynamics studies in India

The land, oceans, and atmosphere are tightly linked and form the most dynamic component of the climate system. Studies on terrestrial and ocean science enhance the understanding on the impacts of climate change. Across India and the world over, human-driven land use and climate changes are altering the structure, function, and extent of natural terrestrial ecosystems and in turn regional biogeochemical feedbacks. In this special issue, we present 29 manuscripts; those discuss wide-ranging aspects of terrestrial and oceanic characterization and dynamics. These contributions are based on selected presentations made at the 2nd International Workshop on Biodiversity and Climate Change (BDCC-2018) held on 24-27 February 2018 at the Indian Institute of Technology Kharagpur, India. The manuscripts are arranged in five sections such as Ecological Assessment, Plant Invasion, Carbon Dynamics, Ecosystem Characterization, and Ocean Dynamics. We realized that the utility of satellite remote sensing data has been emerging as a dominant trend in environmental monitoring and assessment studies in India.

Experimental investigations of argon spark gap recovery times by developing a high voltage double pulse generator

The voltage recovery in a spark gap for repetitive switching has been a long research interest. A two-pulse technique is used to determine the voltage recovery times of gas spark gap switch with argon gas. First pulse is applied to the spark gap to over-volt the gap and initiate the breakdown and second pulse is used to determine the recovery voltage of the gap. A pulse transformer based double pulse generator capable of generating 40 kV peak pulses with rise time of 300 ns and 1.5 μs FWHM and with a delay of 10 μs-1 s was developed. A matrix transformer topology is used to get fast rise times by reducing L(l)C(d) product in the circuit. Recovery Experiments have been conducted for 2 mm, 3 mm, and 4 mm gap length with 0-2 bars pressure for argon gas. Electrodes of a sparkgap chamber are of rogowsky profile type, made up of stainless steel material, and thickness of 15 mm are used in the recovery study. The variation in the distance and pressure effects the recovery rate of the spark gap. An intermediate plateu is observed in the spark gap recovery curves. Recovery time decreases with increase in pressure and shorter gaps in length are recovering faster than longer gaps.

Identification and fine-mapping of Xa33, a novel gene for resistance to Xanthomonas oryzae pv. oryzae

Broadening of the genetic base for identification and transfer of genes for resistance to insect pests and diseases from wild relatives of rice is an important strategy in resistance breeding programs across the world. An accession of Oryza nivara, International Rice Germplasm Collection (IRGC) accession number 105710, was identified to exhibit high level and broad-spectrum resistance to Xanthomonas oryzae pv. oryzae. In order to study the genetics of resistance and to tag and map the resistance gene or genes present in IRGC 105710, it was crossed with the bacterial blight (BB)-susceptible varieties 'TN1' and 'Samba Mahsuri' (SM) and then backcrossed to generate backcross mapping populations. Analysis of these populations and their progeny testing revealed that a single dominant gene controls resistance in IRGC 105710. The BC(1)F(2) population derived from the cross IRGC 105710/TN1//TN1 was screened with a set of 72 polymorphic simple-sequence repeat (SSR) markers distributed across the rice genome and the resistance gene was coarse mapped on chromosome 7 between the SSR markers RM5711 and RM6728 at a genetic distance of 17.0 and 19.3 centimorgans (cM), respectively. After analysis involving 49 SSR markers located between the genomic interval spanned by RM5711 and RM6728, and BC(2)F(2) population consisting of 2,011 individuals derived from the cross IRGC 105710/TN1//TN1, the gene was fine mapped between two SSR markers (RMWR7.1 and RMWR7.6) located at a genetic distance of 0.9 and 1.2 cM, respectively, from the gene and flanking it. The linkage distances were validated in a BC(1)F(2) mapping population derived from the cross IRGC 105710/SM//2 × SM. The BB resistance gene present in the O. nivara accession was identified to be novel based on its unique map location on chromosome 7 and wider spectrum of BB resistance; this gene has been named Xa33. The genomic region between the two closely flanking SSR markers was in silico analyzed for putatively expressed candidate genes. In total, eight genes were identified in the region and a putative gene encoding serinethreonine kinase appears to be a candidate for the Xa33 gene.

Assessing forest canopy closure in a geospatial medium to address management concerns for tropical islands--Southeast Asia

The present study outlines an approach to classify forest density and to estimate canopy closure of the forest of the Andaman and Nicobar archipelago. The vector layers generated for the study area using satellite data was validated with the field knowledge of the surveyed ground control points. The methodology adopted in this present analysis is three-tiered. First, the density stratification into five zones using visual interpretation for the complete archipelago. In the second step, we identified two island groups from the Andaman to investigate and compare the forest strata density. The third and final step involved more of a localised phytosociological module that focused on the North Andaman Islands. The results based on the analysis of the high-resolution satellite data show that more than 75% of the mangroves are under high- to very high-density canopy class. The framework developed would serve as a significant measure to forest health and evaluate management concerns whilst addressing issues such as gap identification, conservation prioritisation and disaster management--principally to the post-tsunami assessment and analysis.

Secalonic acid D blocks embryonic palatal mesenchymal cell-cycle by altering the activity of CDK2 and the expression of p21 and cyclin E

BACKGROUND

The mycotoxin, secalonic acid D (SAD), a known animal and potential human cleft palate (CP)-inducing agent, is produced by Pencillium oxalicum in corn. SAD selectively inhibits proliferation of murine embryonic palatal mesenchymal (MEPM) cells leading to a reduction in cell numbers. These effects can explain the reduction in shelf size and the resulting CP seen in the offspring of SAD-exposed mice. Ability of SAD to inhibit proliferation as well as to block the progression of cells from G1- to S-phase of the cell-cycle were also shown in the human embryonic palatal mesenchymal (HEPM) cells suggesting the potential CP-inducing effect of SAD in human beings

METHODS

Gestation day (GD) 12 mouse embryos and HEPM cells were used to test the hypothesis that the cell-cycle block induced by SAD results from a disruption of stage-specific regulatory components both in vivo and in vitro. The effects of SAD on the activity of various cyclin dependent kinases (CDK) and on the levels of various positive (cyclins and CDK) and negative (CDK inhibitors p15, 16, 18, 19, 21, 27, 57) cell-cycle regulators were assessed by performing kinase assays and immunoblots, respectively.

RESULTS

In the murine embryonic palates, SAD specifically inhibited G1/S-phase-specific CDK2 activity, reduced the level of cyclin E and tended to increase the level of the CIP/kip CDK inhibitor, p21. In the HEPM cell cultures, exposure to IC50 of SAD significantly affected all of the above targets. In addition, a reduction in the levels/activity of CDK 4/6, a reduction in the levels of cyclins D1, D2, D3, E, A, and all INK4 family proteins, and an increase in the level of the CIP/kip CDK inhibitor, p57, were also seen.

CONCLUSIONS

These results suggest that the S-phase-specific cell-cycle proteins CDK2, cyclin E and possibly p21 are the common targets of SAD in murine palatal shelves in vivo and in human embryonic palatal mesenchymal cells in vitro and may be relevant to the pathogenesis of SAD-induced CP.

Inhibition of human embryonic palatal mesenchymal cell cycle by secalonic acid D: a probable mechanism of its cleft palate induction

OBJECTIVE

To assess the mechanism(s) of cleft palate induction by secalonic acid D (SAD) in human embryonic palatal mesenchymal (HEPM) cells and compare them with those evaluated in the murine embryonic palate.

DESIGN

Effect of SAD on HEPM cell proliferation was studied by obtaining dose response curves for cell numbers, uptake of 3H-thymidine and the expression of proliferating cell nuclear antigen (PCNA). Effects of SAD on cell cycle were assessed by flowcytometry. Cell-labeling with 3H-glucosamine and immunoblot analysis were conducted to study SAD effects on the synthesis of glycosaminogycans (GAG) and the expression of fibronectin and tenascin, respectively.

RESULTS

SAD induced a concentration-dependent decrease in HEPM cell number and 3H-thymidine uptake beginning at 0.1 microg of SAD/ml. Expression of PCNA and progression of cell cycle from G1 to S phase were inhibited following SAD exposure. Cell viability was significantly reduced only at 7.5 microg/ml of SAD or higher indicating that the reduction in cell numbers by SAD at lower concentrations is likely due to reduced proliferation and at higher concentrations due to both reduced proliferation and cell death. Synthesis of extra cellular matrix components (GAGs, fibronectin or tenascin) by HEPM cells, however, was not inhibited by SAD.

CONCLUSION

The results of these studies confirmed those of our previous studies with mice and the MEPM cells that SAD may induce cleft palate by reducing numbers of palatal mesenchymal cells by inhibition of their proliferation thereby leading to a reduction in the size of the developing palate shelves.

Isozyme polymorphism and virulence of Indian isolates of the rice sheath blight fungus

Inadequate information about the genetic structure of the polyphagous Rhizoctonia solani has made sheath blight resistance breeding a difficult task. To assess the variability in the Indian populations of sheath blight fungus, 18 isolates were collected from different rice growing regions of India and analyzed for virulence and electrophoretic profiles of 13 isozymes. The virulence spectrum of all 18 isolates was examined on susceptible IR50 and tolerant Swarnadhan varieties, based on which the isolates could be grouped as highly virulent, moderately virulent or avirulent. A total of 11 enzyme systems with 153 electrophoretic phenotypes were applied to characterize the genetic variation among the isolates. Cluster analyses based on isozyme patterns resulted in one major cluster comprising 16 virulent isolates, with two avirulent isolates loosely linked to this at 0.13 similarity. Isozyme systems of esterases (both alpha and beta) and 6-phosphogluconic dehydrogenase could be used to fingerprint the individual isolates.

Ca(2+)-calmodulin antagonist chlorpromazine and poly(ADP-ribose) polymerase modulators 4-aminobenzamide and nicotinamide influence hepatic expression of BCL-XL and P53 and protect against acetaminophen-induced programmed and unprogrammed cell death in mice

Acetaminophen (AAP), the analgesic hepatotoxicant, is a powerful inducer of oxidative stress, DNA fragmentation, and apoptosis. The anti-apoptotic oncogene bcl-XL, and the pro-apoptotic oncogene p53 are two key regulators of cell cycle progression and/or apoptosis subsequent to DNA damage in vitro and in vivo. This study investigated the effect of AAP on the expression of these oncogenes and whether agents that modulate DNA fragmentation (chlorpromazine, CPZ) and DNA repair through poly(ADP-Ribose) polymerase (PARP) activity (4-AB: 4-aminobenzamide) can protect against AAP-induced hepatotoxicity by inhibiting oxidative stress, DNA fragmentation, and/or by altering the expression of bcl-XL and p53. In addition, the protective effect of supplemental nicotinamide (NICO), known to be depleted in cells with high PARP activity during DNA repair, is similarly evaluated. Male ICR mice (3 months old) were administered vehicle alone; nontoxic doses of 4-AB (400 mg/kg, ip), NICO (250 mg/kg, ip) or CPZ (25 mg/kg, ip), hepatotoxic dose of AAP alone (500 mg/kg, ip), or AAP plus one of the protective agents 1 h later. All animals were sacrificed 24 h following AAP administration. Serum alanine aminotransferase activity (ALT), hepatic histopathology and lipid peroxidation, DNA damage, and expression of bcl-XL and p53 (western blot analysis) were compared in various groups. All of the three agents significantly prevented AAP-induced liver injury, lipid peroxidation, DNA damage, and associated apoptotic and necrotic cell deaths, 4-AB being the most effective and NICO the least. Compared to control, there was a considerable decrease in bcl-XL expression, and an increase in p53 expression in AAP-exposed livers. The effect of AAP on bcl-XL was antagonized and that on p53 was synergized by the PARP-modulator 4-AB as well as NICO, whereas the endonuclease inhibitor CPZ was without effect on either bcl-XL or p53 expression. These results suggest that the hepatotoxic effect of AAP involves multiple mechanisms including oxidative stress, upregulation of endonuclease (or caspase-activated DNAse) and alteration of pro- and anti-apoptotic oncogenes. The observed antagonism of AAP-induced hepatocellular apoptosis and/or necrosis by modulators of multiple processes including DNA repair suggests the likelihood that a more effective therapy against AAP intoxication should involve a combination of antidotes.

Secalonic acid D alters the nature of and inhibits the binding of the transcription factors to the phorbol 12-O-tetradecanoate-13 acetate-response element in the developing murine secondary palate

Secalonic acid D (SAD), a mycotoxin produced by Penicillium oxalicum in corn, induces cleft palate (CP) in the offspring of exposed dams. Results of recent studies suggest that protein kinase C (PKC) inhibition by SAD may be relevant to its CP-induction. Downstream effects of PKC are determined by the nature of transcription factors (TF) that form the activator protein-1 (AP-1) and the binding of AP-1 (and other TF) to the phorbol 12-O-tetradecanoate-13 acetate-response element (TRE) to form AP-1-TRE complex, neither of which have been studied in the palate. The aims of the present study were to identify the components of the murine palatal AP-1-TRE complex during development and to uncover the effects of SAD on this complex. Western blots and gel mobility shift assays of control palatal nuclear extracts revealed that, although all relevant TF are present in the palate throughout development, only cyclic-AMP response element (CRE) binding protein (CREB) and CRE-modulator protein-1 (CREM-1) and activating transcription factor-1 bound to TRE on Gestation Day (GD) 12. The pattern shifted to c-Jun and c-Fos (known AP-1 components) on GD 13 and 14. In SAD-treated offspring, however, CREM-1 alone; c-Jun, c-Fos, and CREB; and c-Jun and c-Fos bound to TRE on GD 12, 13, and 14, respectively. Binding of TF to TRE was inhibited by SAD on both GD 12 and 13. These results suggest that a dynamic shift in the binding of TF to TRE from PKA- to PKC-responsive TF occurs during palate development and that teratogens such as SAD can alter both the nature and extent of TF binding to TRE.

Secalonic acid D alters the expression and phosphorylation of the transcription factors and their binding to cAMP response element in developing murine secondary palate

Secalonic acid D (SAD), a cleft palate-inducing mycotoxin, reduces palatal cyclic AMP (cAMP) levels. cAMP relays its signals via the transcription factors (TF) such as cAMP response element (CRE) binding protein (CREB), CRE modulator (CREM) and activator transcription factor-1 (ATF-1) to CRE-containing genes. These studies tested the hypothesis that these TF are present and functional in the developing palate and that SAD alters their expression and function along with that of the CRE-containing gene, proliferating cell nuclear antigen (PCNA). Electrophoretic mobility shift assays (EMSA), using nuclear extracts of control and SAD-treated developing palate tissues and 32P-labeled CRE revealed the formation of a DNA-protein complex. Supershift/ablation assays with TF antibodies showed the presence of CREB, CREM and another unidentified TF but not ATF-1 in the complex. Western analyses of the DNA-protein complex from preparative EMSA revealed increased binding of CREB to CRE in direct correlation with increase in phospho-CREB (pCREB) in the controls. Exposure to SAD significantly reduced CREB binding throughout palate development. This was in correlation with reductions in pCREB levels on gestational day (GD) 13 and 14 palates. On GD 12, however, SAD dramatically increased CREB phosphorylation. The ontogeny of palatal CREB and CREM (several isoforms) expression remained unchanged in controls whereas SAD increased that of the repressor isoform of CREM. The expression of PCNA was inhibited by SAD on GD 12. These results show that the cAMP signaling pathway is functional in the palate and that SAD alters CREB phosphorylation and inhibits its binding to CRE. leading to altered expression of genes involved in cell proliferation, an event critical for normal palate development.

Novel mechanism of protein kinase C inhibition involving the pseudosubstrate region by secalonic acid D in vitro

Evidence from studies in mice suggests a mechanistic role for the inhibition of conventional isoforms of protein kinase C (cPKC) in the development of cleft palate (CP) in the offspring of female mice treated with the mycotoxin, secalonic acid D (SAD). These experiments were aimed at assessing whether SAD inhibits commercially available pure cPKC (PKCalpha, -beta, -gamma) and at identifying the mechanism of such an inhibition in vitro. Secalonic acid D inhibited the three isozymes similarly (IC50 of 5 to 6.2 microM by direct extrapolation and 2.7 to 4 microM by logarithmic regression). The loss of inhibitory effect of SAD upon removal of the regulatory domain of PKCbetaII, the most predominant cPKC in the palate, suggested that the inhibition was mediated by the regulatory subunit. Kinetic analysis suggested a lack of competitive interaction for SAD with the binding sites for Ca(2+) and phosphatidyl serine (PS). Antibody directed against residues 19-32 of the pseudosubstrate region of PKCbetaII, however, competitively reversed the inhibition of PKCbetaII by SAD, suggesting that the pseudosubstrate is the site of interaction of SAD. Further, SAD inhibited the cleavage of the pseudosubstrate from PKCbetaII by the endoproteinase Arg-C. The fact that the activity of Arg-C itself was not inhibited by SAD suggests that SAD interferes with the preceding step involving the cofactor-induced release of the pseudosubstrate from the active site of PKCbetaII, a novel mechanism.

Expression and activity of protein kinase C isoenzymes during normal and abnormal murine palate development

Protein kinase C (PKC) plays a critical role in signal transduction, mediating various cellular events critical for normal development, including that of the palate. In vivo and in vitro studies suggest the relevance of the inhibition of PKC by the mycotoxin, secalonic acid D (SAD), to its induction of cleft palate (CP) in mice. In the present study, temporal and spatial expression and the activity of various PKC isoenzymes were studied in the control and SAD-exposed murine embryonic palate during gestational days (GD) 12-14.5 by western blotting, immunohistochemistry, and phosphotransfer assay. The Ca2+-dependent isoenzymes, PKC alpha and PKC betaII, showed significant expression on GD 12.0, which gradually decreased through GD 14.5, whereas PKC betaI and PKC gamma were negligible throughout. All Ca2+-independent isoenzymes (epsilon, delta, and zeta) were expressed more abundantly and, in contrast to the Ca2+-dependent ones, progressively increased with age. SAD failed to alter this pattern of expression but enhanced the phosphorylation of PKC epsilon throughout development. Immunohistochemical analysis revealed an isoenzyme-specific distribution of PKC between the epithelium and mesenchyme. As expected, SAD significantly inhibited the total Ca2+-dependent PKC activity in palatal extracts. Although total Ca2+-independent PKC activity in palatal extracts was unaffected by SAD, individual pure isoenzymes were either selectively inhibited (PKC zeta), stimulated (PKC delta), or unaffected (PKC epsilon) by SAD. These results show that PKC isoenzymes exhibit dynamic temporal and spatial patterns of expression and activity in the developing palate and that the induction of CP by SAD is associated with an alteration in their activation and/or activity.

An unusual complication of an ankle arthroscopy and its management

This report describes a case of a routine ankle arthroscopy which went awfully wrong. In trying to excise a loose body the surgeon had excised the distal fibula. A reasonable solution to the problem now facing the patient would have been an ankle fusion. The authors, however, performed an osteoarticular fibular grafting. At 34 months, this has been a success so far clinically and radiologically. Both the complication and its treatment have not been described before.

Chondromyxoid fibroma of bone presenting as chronic back pain

OBJECTIVE

To discuss a case of chondromyxoid fibroma presenting with low back pain.

CLINICAL FEATURES

A 50-yr-old man had an 8-yr history of low back pain. This was diagnosed and treated as arising from the disc and caused by spinal stenosis. Magnetic resonance imaging findings supported the clinical findings. Years later, a plain radiograph of the pelvis revealed an incidental abnormality of the right ilium, and the patient was subsequently referred to a musculoskeletal tumor center for treatment.

INTERVENTION AND OUTCOME

The lesion was surgically removed and the defect was reconstructed via bone allograft.

CONCLUSION

Such tumors are a rare cause of back pain. Tumors of the pelvis can at times present as back pain. In cases of refractory back pain, an X-ray of the pelvis can be a useful screening investigation. Chondromyxoid fibromas are rare tumors best treated by excision if they are amenable or by curettage and bone grafting procedures.

Developmental effects of fumonisin B1 in mice

Developmental and toxic effects of aqueous extracts of F. moniliforme culture material containing known levels of fumonisin B1 were recently reported in mice and included maternal hepatotoxicity and lethality, maternal body weight gain reduction, increased embryonic resorptions, reduced offspring body weights, and fetal malformations including cleft palate, hydrocephalus, malformed ribs and incomplete digital and sternal ossification. These studies also suggested that the effects of the fungal extract on the mouse offspring may be mediated via maternal effects. The contribution of fumonisin B1 (FB1), a major toxic metabolite of F. moniliforme, in the induction of these effects was evaluated in this study by administering 0 to 100 mg pure FB1/kg of body weight on gestational days (GD) 7 through 15 to pregnant Charles River CD1 mice and assessing maternal health and fetal development till the end of gestation. Doses of 25 mg/kg or higher of pure FB1 induced maternal liver lesions (mostly necrotic changes), associated with ascites and increased hepatocytic nuclear diameter. Fumonisin doses of 50 mg/kg or higher also resulted in significantly increased maternal ALT on GD12, and reduced offspring bodyweights on GD18. Increased resorptions and decreased numbers of live offspring were only evident at 100 mg FB1/kg body weight. Offspring exhibited dose-dependent increase in the incidence and severity of hydrocephalus of both the lateral and third ventricles at doses of 25 mg/kg or higher. Doses of 25 mg/kg or higher also increased the sphinganine/sphingosine (Sa/So) ratios in maternal but not fetal livers. These results suggest that FB1 may be a developmental toxicant accounting for most but not all earlier reported effects of F. moniliforme culture extract. Association of FB1 effects on the offspring with maternal hepatoxicity and with alteration of Sa/So ratio in maternal but not fetal liver supported the earlier claim that FB1 effects on the mouse offspring are mediated by maternal hepatotoxicity.

Retrospective evaluation of production characteristics in Sinclair miniature swine--44 years later

Three hundred seventy-one litter records collected between 1985 and 1993 from 156 Sinclair S-1 miniature sows, a Hormel-derived strain of miniature swine, were retrospectively analyzed and compared with published records for 1950 to 1952 and 1963 to 1965. The effect of several variables such as season and month of parturition, age of sow, parity, and litter size on reproductive parameters of the Sinclair miniature swine were evaluated. The mean and standard error of the mean for litter size, number of liveborn, number of stillborn, and litter size at weaning of the Sinclair S-1 miniature swine were 7.20 +/- 0.12, 6.57 +/- 0.12, 0.63 +/- 0.06, and 5.75 +/- 0.12 piglets respectively. From a total of 2,436 liveborn piglets, 2,133 (87.56%) were weaned. The litter size at birth was similar to that previously reported for this strain of swine, whereas the litter size at weaning increased (P < 0.001) from 4.7 piglets during 1963 to 1965 to 5.8 piglets in our study. The average birth weight decreased (P < 0.001) from 0.90 kg in 1950 to 1952 and 0.72 kg in 1963 to 1965 to 0.59 kg in our study. Reproductive variables that had a considerable effect on the miniswine reproduction included month of parturition, age of sow, parity, and litter size. Primiparous sows had the smallest litter size and lowest number of weaned piglets. Sows during their second and third parity or sows between 2 and 4 years old had the best reproductive performances. Litter size and number of stillborn increased with parity and age of sow, resulting in fewer piglets weaned in older sows.(ABSTRACT TRUNCATED AT 250 WORDS)

Developmental effects of fumonisin B1-containing Fusarium moniliforme culture extract in CD1 mice

Pregnant Charles River CD1 mice were treated with a semipurified extract of Fusarium moniliforme culture containing 0, 12.5, 25, 50 or 100 mg FB1/kg each day orally (diluted in distilled water) between gestational days (GD) 7 and 15 to evaluate the developmental toxicity of FB1. Following sacrifice of dams on GD 18, litters were examined for gross abnormalities and divided equally for skeletal or visceral examination by routine techniques. Significant maternal mortality was observed at doses of 50 and 100 mg FB1/kg. Dose-dependent decreases in maternal body weight gains, number of live offsprings per litter, and mean body weight of the offspring were produced at FB1 doses of 25 mg/kg or higher. The percentage of implants resorbed increased at all doses in a dose-dependant manner. A dose-dependant increase, except at the lowest dose tested, in the incidence of ossification deficits involving digits and sternum, short and wavy ribs, and hydrocephalus of lateral and third ventricles was also evident. Cleft palate was seen only at the highest FB1 dose. Maternal intoxication manifested as a dose-dependant increase in the severity of ascites associated mainly with increased histopathologic scores reflecting hepatocellular damage at day 18. Concommittant increases in serum alanine amino transferase (ALT) on GD 12, reflecting parenchymal liver cell damage, was also observed at all doses above 12.5 mg of FB1/kg. These results suggest that FB1-containing F. moniliforme culture extract is developmentally toxic in mice, and that this toxicity may be mediated by maternal hepatotoxicity.

Inhibition of adenylate cyclase in perfusion mouse palate by secalonic acid D

Glucocorticoids (GC) induce cleft palate (CP) in the offspring of exposed pregnant mice. Glucocorticoids induce prostaglandin (PG) synthesis inhibition via reduced arachidonic acid (AA) release from membranes, and this results from inhibition of phospholipase A2. This metabolic event is associated with reduced palatal cAMP levels in the prefusion stages (d 13 of gestation). The mycotoxin secalonic acid D (SAD) induces CP in the offspring born to treated mothers, elevates maternal plasma corticosterone levels, and reduces prefusion palatal cAMP levels. In addition, an increase in cAMP was noted in the postfusion period (d 15 of gestation). Since exogenous AA given simultaneously to GC-exposed mothers may protect against GC-induced CP in the offspring, such a possibility was tested for SAD. Pregnant CD1 mice given a teratogenic dose of SAD (30 mg/kg, ip, on gestational d 11) were simultaneously treated with maximal tolerated doses of AA (200 mg/kg, sc, on gestational d 11, 12, and 13). At term, no significant reduction in SAD-induced CP was seen as a result of AA treatment. To evaluate if SAD-induced alterations in palatal cAMP are due to reduced palatal membrane-associated adenylate cyclase (AC) activity during pre- and postfusion periods, SAD-treated mothers were sacrificed at 12-h intervals between gestational d 13.5 and 15.5, palate shelves were collected from the fetuses, and AC activity (cAMP formed/mg protein/min) was assayed in the presence or absence of the enzyme stimulator, sodium fluoride (NaF). Although SAD did not alter unstimulated AC activity, it significantly reduced the NaF-induced stimulation of enzyme activity in the prefusion period. This inhibition could not be reversed by excess GTP in the incubation mixture. Since NaF stimulation of AC indicates post-receptor-site function involving GTP-binding and catalytic units, and since addition of GTP failed to correct SAD-induced alteration of NaF stimulation of the enzyme, it is suggested that SAD may inhibit the AC sensitivity to stimuli by its effect on the catalytic unit in a manner that does not affect enzymic basal activity.

Interaction of dimethylsulfoxide and arachidonic acid with the teratogenic effects of caffeine in mice

Dose-response of the teratogenic effect of caffeine (CA) and the potential role of facial hematomas in the pathogenesis of caffeine-induced cleft palate were investigated using CD1 mice treated with 150, 200, or 250 mg CA/kg i.p. on gestational day (GD) 12. Dimethylsulfoxide (DMSO; 20%) and arachidonic acid (AA, 200 mg/kg) were administered along with CA (200 mg/kg) to study their interaction with CA-induced teratogenesis and elevation in maternal glucocorticoids (MGC, measured by RIA) on GD 13 and 14. Dose-dependent increase in the incidence of cleft palate (CP) was noted in CA-exposed mice. High maternal deaths, an increased number of resorptions, gross facial hematomas (GFH), and club foot (CF) were produced only by the highest (250 mg/kg) dose of CA. Palates from all offspring with GFH were clefted at this dose level. None of the control or CA-treated nonclefted offspring had GFH or microscopic hematomas (MH). At 200 mg/kg of CA, DMSO in combination with CA actually increased CA-induced CP from 30% to 100% and also produced 100% GFH as compared to 0% by CA alone at this dose. Greater than 50% of clefted offspring without GFH, given either dose (200 or 250 mg/kg) of CA, had MH. Very high levels of MGC were present in CA-treated mice on GD 13 and 14. Although simultaneous administration of DMSO reduced the magnitude of CA-induced MGC elevations on GD 14, the MGC levels remained high for greater than 24 hours following CA exposure. Increase in maternal mortality and fetal resorptions, a decrease in the number of live pups and their body weights, and no change in the incidence of CP were seen when CA-treated mice were simultaneously exposed to AA. These results suggest a correlation between caffeine-induced FH and CP; a role for increased hematomagenic effects of DMSO in its potentiation of the cleft-palatogenic effect of caffeine; and absence of a role for AA-mediated effects of MGC in the causation of CA-induced CP and other malformations.

Alteration in the tissue retention of [14C]-caffeine in pregnant mice by dimethylsulfoxide

This study was undertaken to investigate if dimethylsulfoxide (DMSO)-induced potentiation of maternal toxicity and teratogenicity of caffeine (CA) is mediated by DMSO-induced alteration of CA levels in maternal and fetal tissues. Pregnant CD 1 mice were given single dose of [14C]-caffeine intraperitoneally (i.p.) on gestational day 12, in distilled water (DW) or 20% (v/v) solution of DMSO in DW. At 6, 12, and 24 hr following dosing, radioactivity in various maternal and fetal tissues was compared. Significantly (P < or = 0.05) higher CA-derived radioactivity was seen in maternal brain, carcass and heart as well as placenta and fetal heads and bodies 6 hr after dosing with CA in DMSO compared to CA in DW. A concomitant reduction in urinary excretion of CA-derived radioactivity in DMSO group or compared to CA in DW was observed at this time. At 12 hr following dosing, significantly (P < or = 0.05) higher CA-derived radioactivity was noted in maternal heart, brain, and carcass; placenta; and fetal bodies in mice receiving CA in DMSO compared to those receiving CA in DW. These results suggest that increased accumulation of CA in certain maternal and fetal tissues could contribute to the observed increase in maternal and fetal toxicity of CA by DMSO.

Neurotoxic effects of secalonic acid D in mice during subchronic postnatal exposure

To establish a dose-response of neurotoxic effects to daily oral doses of the mycotoxin secalonic acid D (SAD), as well as to correlate the neonatal behavioral responses to smaller doses of SAD with the attendant neurochemical effects in mice, 5 neonates of each sex were placed with each mother and 4 litters were treated orally with 0 to 5 mg/kg of SAD daily from postnatal day (PND) 3 through 35. Body weights, toxic signs, and mortality were used to arrive at no observable effect level (NOEL). Performance in several behavioral tests and changes in regional norepinephrine and dopamine levels in the brains of neonates treated with SAD at NOEL (1.25 mg/kg/day) or below were evaluated at selected times during SAD exposure. Doses as low as 1.25 mg/kg/day reversibly reduced body weights in both sexes on PND 12 and 13 compared to controls, whereas doses of 2.5 mg/kg/day or greater were lethal (LD50 of 2.5 mg/kg/day). Toxic signs observable in neonates receiving 2.5 mg/kg/day or more of SAD included fine body tremors, uncoordinated movements, hindlimb weakness, circling, loss of righting reflex, paddling, and terminal coma. Ontogeny of cliff avoidance (PND 5, 7, and 9), hindlimb grip response (PND 14, 17, and 20), olfactory discrimination (PND 8 through 11) and swimming (PND 13 through 21) were significantly delayed by SAD exposure: some even at 0.625 mg/kg/day. Dopamine levels significantly increased on PND 13 and decreased on PND 20 only in the olfactory lobe of SAD-exposed neonates. Norepinephrine levels were unchanged in all the brain regions examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Microbial models of mammalian metabolism: biotransformations of phenacetin and its O-alkyl homologues with Cunninghamella species

1. The analgesic compound phenacetin and its O-alkyl homologues were metabolized by Cunninghamella elegans to yield the O-dealkylation product paracetamol (acetaminophen), and metabolites resulting from omega-1 hydroxylation and further oxidations. 2. Structural identification was based upon physical, spectral and chromatographic comparisons of isolated metabolites with synthetic standards generated by alkylation of paracetamol with the appropriate alkyl halide, epoxide, or alpha,beta-unsaturated ketone. 3. The rank order of O-dealkylation within the homologous series based upon either substrate disappearance or phenol formation was found to be ethyl greater than isopropyl greater than n-propyl greater than n-butyl greater than methyl.

Role of maternal plasma corticosterone elevation in the teratogenicity of secalonic acid D in mice

Secalonic acid D (SAD) is a teratogenic mycotoxin that causes cleft palate in the offspring of treated pregnant mice. To investigate the role of maternal corticosterone in the teratogenicity of SAD, pregnant CD-1 mice were treated with 30 mg/kg of SAD i.p. on day 11 of pregnancy in either 5% (w/v) NaHCO3 or 20% (v/v) dimethyl sulfoxide (DMSO) in NaHCO3. Radioimmunoassay (RIA) was performed to determine plasma corticosterone at 24, 48, 72, and 96 hr after dosing. No interference by EDTA, SAD, DMSO, or pentobarbital was noticed on the RIA. Significant (P less than .01) elevations in plasma corticosterone concentrations were seen 24 and 48 hr following dosing of SAD in NaHCO3 with concentrations reaching a peak just prior to the onset of shelf elevation and fusion. Simultaneous treatment with DMSO, an agent known to antagonize the teratogenic effect of SAD, completely abolished the SAD-induced corticosterone elevation at the 24 hr time point and significantly (P less than .01) reduced it at the 48 hr time point. To evaluate the specificity of the role of corticosterone in the teratogenicity of SAD, plasma samples from mature males similarly treated with either single or multiple doses of SAD ranging from 15 to 45 mg/kg were assayed for corticosterone. A dose of SAD comparable to that used in the pregnant females failed to significantly change plasma corticosterone concentrations in the males. An elevation corresponding only to 75% of that in the females was seen in males receiving multiple doses of SAD totaling three times the dose used in the females. As with females, DMSO completely abolished plasma corticosterone elevation by SAD in the males. These results demonstrate, for the first time, the effect of SAD on a mammalian endocrine system and provide evidence for a specific involvement of elevated maternal plasma corticosterone concentrations in SAD teratogenicity.

Mechanism of dimethylsulfoxide protection against the teratogenicity of secalonic acid D in mice

Dimethylsulfoxide (DMSO) is known to antagonize the teratogenic effects of secalonic acid D (SAD) in mice. To establish the optimum protective dose of DMSO, pregnant CD-1 mice were treated, i.p., with 30 mg/kg of SAD in 5% (w/v) NaHCO3, containing 0, 10, 20, or 30% (v/v) DMSO on day 11 of gestation. Data indicate that at 10% and 20% levels, DMSO affords an apparent dose-related protection against SAD-induced cleft palate, whereas 30% DMSO enhanced fetal resorption with no reduction in the incidence of cleft palate. Ultraviolet spectra and TLC mobility indicated that DMSO at 20% did not directly interact with SAD. Distribution and elimination of 14C-SAD was studied in fetal and maternal tissues from pregnant mice at 24 and 48 hr after exposure to 30 mg/kg of 14C-SAD, i.p., in NaHCO3 (control) or in 20% DMSO. Compared with those not receiving DMSO, maternal exposure to DMSO: 1) significantly reduced (42-75%) radioactivity in fetal heads and bodies, placenta, and maternal tissues other than liver; 2) significantly increased (up to 222%) the radioactivity in maternal liver; and 3) significantly reduced (44-58%) fecal and urinary elimination of SAD-derived radioactivity. These results suggest that the antiteratogenic effect of DMSO against SAD may be at least partly mediated by increased SAD (or its metabolites) retention by maternal liver leading to reduced SAD uptake by the fetus.

Secalonic acid D-induced changes in palatal cyclic AMP and cyclic GMP in developing mice

Secalonic acid D (SAD) induces cleft palate in the developing mouse by an unknown mechanism. To investigate possible roles of cyclic nucleotides (cAMP and cGMP) in the teratogenesis of SAD, cAMP and cGMP levels were measured in the extracts of fetal palates of gestational age 13(0) through 16(12) (days(hours]. Fetuses were obtained from pregnant CD-1 mice treated on day 11(0) of gestation, with either 5% (wt./vol.) sodium bicarbonate (NaHCO3, control) or 30 mg/kg of SAD in 5% NaHCO3, intraperitoneally (i.p.). Radioimmunoassay was used to quantitate cyclic nucleotide levels. Cyclic AMP levels peaked on day 14(12) of gestation in controls. In the SAD group there was a significant decrease in cAMP levels on days 13(12) and 14(0) of gestation and a decrease of 30% in total cAMP on days 13(0) through 14(0) of gestation, with little or no change at the peak on day 14(12). On day 15(12), however, the SAD group had a 68% increase in palatal cAMP level over the control. Control levels of cGMP appeared to follow a diurnal pattern reaching maximal levels at the end of the dark cycle. In contrast, SAD decreased the cGMP level by 31% on day 13(12) (P less than 0.05) and increased it 100% above that of the control level on day 15(0) (P less than 0.01). Total cGMP during days 15(0) through 16(12) of gestation was 33% higher than control (P less than 0.01). The number of clefts in the SAD group was significantly higher at all points following palate closure in the control fetuses (14(0) through 16(12] with values ranging from 20% to 34% versus 0% in the control (P less than 0.01-0.005). Morphological changes on days 13(0) through 15(0) indicated a failure of shelf elevation in middle and posterior palatal regions of SAD-treated fetuses. These results suggest that the induction of cleft palate by SAD is associated with dynamic changes (initial decrease followed by later increase), in vivo, in established cyclic nucleotide patterns and support a mechanistic role for cyclic nucleotide-mediated cellular processes in normal as well as abnormal palate development.

Developmental stage specificity and dose response of secalonic acid D-induced cleft palate and the absence of cytotoxicity in developing mouse palate

Incidence of cleft palate (CP) in full-term mouse fetuses was evaluated following administration of 25 mg/kg of the mycotoxin, secalonic acid D (SAD), to groups of female mice on each of Days 10, 11, 12, 13, 14, or 15 of pregnancy. Although the highest numerical incidence (45.3%) of cleft palate resulted following SAD exposure on Day 12 of pregnancy, and the response tapered off to 16.9% on Day 10 and 0% on Day 15 of pregnancy, similar responses were produced also following exposures on Days 11 (38.4%) and 13 (39.9%) of pregnancy. Maternal exposure to doses of 0, 15, 20, 25, or 30 mg/kg of SAD, given on Day 12 of pregnancy indicated that although fetuses in the 30-mg/kg group had the highest incidence (51.9%) of CP, the effect was associated with increased resorptions and decreased fetal weights. The 25-mg/kg dose was optimally teratogenic (45.3% cleft palate) and maximally tolerable with neither an increase in resorptions nor a decrease in fetal body weights. Cytotoxicity of the optimally teratogenic dose of SAD (25 mg/kg given ip) on Day 12 of pregnancy was evaluated as a possible mechanism of SAD teratogenicity using indices such as mesenchymal cell density, mitotic index, and the uptake of [3H]thymidine in the developing palatal shelves. No evidence of SAD cytotoxicity was obtained in palatal shelves indicating a possible role for nonlethal cellular effects of SAD in the pathogenesis of CP. These studies also suggest the suitability of the maternal 25-mg/kg dose of SAD to study cellular biochemical effects in the developing embryo without the complicating influence of cytotoxic effects.

Reduced cadmium body burden in cadmium-exposed calves fed supplemental zinc

The objectives of this study were to evaluate the use of practical supplemental dietary zinc to modify the cadmium content in edible bovine tissues and to identify copper interactions with cadmium and zinc. The effect of supplemental zinc (200 or 600 micrograms/g) on the concentrations of cadmium, zinc, and copper in liver, kidney cortex, muscle, and blood of calves fed 50 micrograms/g cadmium for 60 days was evaluated. Blood samples were collected before and eight times after starting to feed cadmium or cadmium plus zinc. Liver, kidney, and muscle samples were collected when calves were slaughtered (baseline, at beginning of experimental feeding; cadmium-fed, at end of 60 days feeding). The cadmium concentrations of all sample types collected were markedly increased by the feeding of cadmium. Feeding 600 micrograms/g supplemental zinc significantly increased the zinc concentrations of liver, kidney cortex, and blood and decreased the cadmium accumulation in these organs as well as muscle. The copper concentrations of muscle or blood were not altered by feeding cadmium with or without zinc but those of liver and kidney cortex were significantly increased by higher dietary levels of zinc and cadmium. The potential use of dietary zinc salts in reducing cadmium body burden in food animals suspected or known to have high cadmium intakes is suggested.

Interaction of secalonic acid D with phenobarbital, 3-methyl cholanthrene, and SKF-525A in mice

Secalonic acid D (SAD) is an acutely toxic and teratogenic fungal metabolite produced by Penicillium oxalium in corn and other cereal grains. Experiments were conducted to study the effects of single and multiple doses of SAD on pentobarbital-induced narcosis, as an index of the modulating effect of SAD on the hepatic drug metabolizing enzymes in mice. The effects of known enzyme modulators-phenobarbital (PB), 3-methyl cholanthrene (3-MC), and diethylaminoethyl diphenylproply acetate hydrochloride (SKF-525A)-on the acute toxicity of SAD in mice were also studied using body weights, mortality, and histopathology as indices. Results of this study failed to demonstrate any modulating effect by SAD of pentobarbital metabolizing enzymes. Pretreatment with SKF-525A, an enzyme inhibitor, enhanced SAD toxicity in mice, whereas pretreatment with PB or 3-MC, known enzyme inducers, had no effect. Further studies of interaction of [14C]SAD with PB and SKF-525A revealed that although neither PB nor SKF-525A altered the ratio of parent compound to total metabolites excreted in bile, SKF-525A significantly reduced the bile flow as well as the elimination of SAD-derived radioactivity in bile. These results strongly suggest the possibility that the effects of SKF-525A, other than the enzyme inhibition, may be responsible for its enhancement of SAD toxicity in mice.

High-performance liquid chromatographic analysis of the mycotoxin secalonic acid D and its application to biological fluids

Secalonic acid D (SAD) is an acutely toxic, teratogenic and possibly mutagenic fungal metabolite produced in corn by Penicillium oxalicum. Using ultraviolet absorbance at 340 nm as a means of detection, SAD was resolved as a sharp peak by reversed-phase high-performance liquid chromatography (HPLC) on a small particle (10 mu m) mu Bondapak C18 column in 4 min by an acetonitrile--water--glacial acetic acid-tetrahydrofuran (5:3:0.5:0.5 for solvent system A and 4:3:0.5:0.5 for solvent system B) elution solvent system. The flow-rates for the two solvent systems (A and B) were 1.5 and 1.7 ml/min; column operating pressures of 1500 and 1800 p.s.i., respectively, resulted. The relationship between peak height or peak area and the quantity of SAD injected was linear over a range of 1--50 ng. Detection was very sensitive with lower limits of detection of 0.6 and 0.7 ng of SAD in solvent systems A and B, respectively. Retention times, peak heights and peak areas were highly reproducible in both solvent systems. Detection of SAD in spiked (0.2--10 mu g/ml) urine and bile samples injected without cleanup onto the HPLC column and quantitative extraction of SAD by ethyl acetate from spiked, acidified plasma samples (0.1--5 mu g/ml) followed by HPLC analysis were obtained. Solvent system B gave better resolution of SAD from the interfering substances in bile and urine than solvent system A. However, sensitivity was slightly greater in solvent system A.

Teratogenicity of secalonic acid D in mice

Teratogenicity and fetotoxicity of secalonic acid D, a toxic fungal metabolite produced by Penicillium oxalicum, were investigated with pregnant CD1 mice. The compound was administered ip on d 7-15 of pregnancy. A dose-dependent reduction in weight gain of mothers receiving all doses of secalonic acid D and an increase in resorptions of implanted embryos of dams treated with more than 5 mg/kg secalonic acid D occurred. The latter effect was nearly 100% at 15 or 9 mg/kg given in NaHCO3 with or without dimethyl sulfoxide (DMSO), respectively. A corresponding decrease in the percent of live fetuses and a decrease in the average fetal body weight on d 19 of pregnancy also occurred. Multiple gross, skeletal, and visceral anomalies were noted in fetuses born to mothers receiving 10 mg/kg or more in NaHCO3 containing DMSO. In NaHCO3 alone, the minimum teratogenic dose was 6 mg/kg. Major malformations included cleft palate, cleft lip, open eyelids, missing phalangeal ossification centers, and shortened mandibles. The results indicated that secalonic acid D is embryocidal and teratogenic as well as fetotoxic when given to female CD1 mice during pregnancy.

Mutagenicity of secalonic acid D in mice

Secalonic acid D is an acutely toxic and teratogenic mycotoxin, produced by Penicillium oxalicum in corn. Two rodent mutagenicity tests, the dominant lethal test designed to evaluate male germ cell mutations and the micronucleus test designed to evaluate somatic cell mutations, were conducted in mice to assess the carcinogenic potential of secalonic acid D. Data obtained indicate that the positive control compound triethylene melamine (TEM) induced dominant lethal mutations during weeks 1 through 4 after administration to male mice and also resulted in a greatly increased population of micronucleated polychromatic (immature) erythrocytes in bone marrow of treated male mice. Secalonic acid D, however, failed to induce dominant lethal mutations but produced a slight but statistically significant increase in the number of micronucleated polychromatic erythrocytes in mouse bone marrow at maximally tolerated doses. It is concluded that secalonic acid D may e weakly mutagenic in a mouse somatic cell mutation system.

Toxicity of Secalonic acid D

Toxicity of secalonic acid D was examined by using lethality, growth retardation, and histopathology as indexes. The ip LD50 values of 37, 31, and 27 mg/kg were obtained for Charles River CD-1, Texas (ICR), and Sprague-Dawley (CF-1) strains of mice, respectively. The ip LD50 was 52 mg/kg in female CD-1 mice. The iv LD50 was 25 mg/kg in CD-1 male mice. Oral LD50 values of 400 mg/kg in male CD-1 mice and 25 and greater than 400 mg/kg in Sprague-Dawley day-old and weanling (21 d) rats of both sexes, respectively, were obtained. Doses of 20 mg/kg or more ip retarded growth and doses of 30 mg/kg or more ip were lethal to CD-1 mice. Oral doses required to produce such effects in day-old rats were 5 and 20 mg/kg (or higher), respectively. All ip doses of secalonic acid D caused pulmonary atelectases and foccal peritonitis in male CD-1 mice. The latter involved surfaces of abdominal viscera and produced limited subcapsular necrosis of hepatic parenchyma. Exposure to a single lethal dose iv (25 mg/kg or more) of secalonic acid D caused limited hepatic portal necrosis but no peritonitis or other associated local effects observed in CD-1 male mice after ip exposure. Cytoplasmic liposis and loss of glycogen and RNA from hepatocytes were observed in a single mouse receiving 50 mg/kg iv. Death resulting from cardiac and/or pulmonary insufficiency was suggested by atelectasis, pulmonary hemorrhages and edema, and massive atrial dilation in mice that died after lethal ip or iv doses of secalonic acid D. Five daily sublethal ip doses in CD-1 male mice resulted in dose-dependent mortality (LD50, 11.5 mg/kg) indicating cumulative effects.

Teratogenic and dominant lethal studies of patulin in mice

Teratogenicity of daily intraperitoneal (i.p.) injections of 1.5 or 2.0 mg/kg of patulin on days 6 through 17 of pregnancy and mutagenic effects of acute i.p. exposure of 3.0 mg/kg of patulin on male germ cells were evaluated. Resorption of all implanted embryos occurred at 2.0 mg/kg/day of patulin, while a significant reduction in the average body weight of 19-day-old fetuses from patulin-treated mothers, compared to control fetuses, was noticed at 1.5 mg/kg/day without any lethal effects on the implanted embryos. Patulin was embryocidal, possibly fetotoxic but was neither teratogenic nor mutagenic to mice.