A review on physico-chemical delignification as a pretreatment of lignocellulosic biomass for enhanced bioconversion

Effective pretreatment of lignocellulosic biomass (LCB) is one of the most important steps in biorefinery, ensuring the quality and commercial viability of the overall bioprocess. Lignin recalcitrance in LCB is a major bottleneck in biological conversion as the polymerization of lignin with hemicellulose hinders enzyme accessibility and further bioconversion to fuels and chemicals. Therefore, there is a need to delignify LCB to ease further bioprocessing. The efficiency of delignification, quality and quantity of the desired products, and generation of inhibitors depend upon the type of pretreatment employed. This review summarizes different single and integrated physicochemical pretreatments for delignification. Additionally, conditions required for effective delignification and the advantages and drawbacks of each method were evaluated. Advances in overcoming the recalcitrance of residual lignin to saccharification and the methods to recover lignin after delignification are also discussed. Efficient lignin recovery and valorization strategies provide an avenue for the sustainable lignocellulose biorefinery.

Eco-friendly and facile synthesis of size-controlled spherical silica particles from rice husk

The valorization of inorganic silica components from rice husk has been considered an important research topic over the last few decades. However, owing to various problems, such as the difficulty in controlling precise morphological properties, complex extraction and manufacturing processes, and the use of hazardous acids, the technology for producing high value-added silica for industrial applications is still insufficient. In this study, we developed a method for obtaining size-controlled spherical silica from rice husk using an eco-friendly and simplified process that overcomes the above-mentioned limitations. Silica particles were obtained by extraction from rice husk in alkaline media under mild conditions (80 °C) followed by pH adjustment with acetic acid. Therefore, the use of strong acids was excluded, no special equipment was required for the process, and the overall synthetic process was significantly simplified. The silica particles obtained through this method were uniformly spherical in shape, with a surface area of more than 200 m² g^-1. Our results indicate that the preparation of silicate solution under appropriate conditions and the use of polyethylene glycol (PEG) additives during the precipitation step are important for obtaining spherical silica. Moreover, by adjusting the temperature in the precipitation step, the size of the spherical silica particles can be controlled in the range of ∼250 nm to ∼1.4 μm. Our study contributes to the development of rice husk-derived silica that can be applied to practical industrial applications.

Immobilization of laccase via cross-linked enzyme aggregates prepared using genipin as a natural cross-linker

Genipin is a nontoxic natural cross-linker that was successfully used to prepare cross-linked enzyme aggregates (CLEAs) of Trametes versicolor laccase. The recovered activity of CLEAs was influenced by the co-solvent type, genipin concentration, cross-linking time, preparation pH, and bovine serum albumin (BSA; amino group feeder) concentration. The characteristics of CLEAs prepared using genipin under optimal conditions (genipin-BSA-CLEAs) were compared with those of typical CLEAs prepared using glutaraldehyde or dextran polyaldehyde. Genipin-BSA-CLEAs were nano-sized (average diameter, approximately 700 nm), had a ball-like shape, showed a narrow size distribution, and exhibited the highest substrate affinity among the prepared CLEAs. The thermal stability of genipin-BSA-CLEAs was 6.8-fold higher than that of free laccase, and their pH stability was also much higher than that of free laccase in the tested range. Additionally, genipin-BSA-CLEAs retained 85% of their initial activity after 10 cycles of reuse. Particularly, genipin-BSA-CLEAs showed higher thermal and pH stability than CLEAs that were cross-linked using glutaraldehyde. Therefore, genipin represents an alternative to toxic compounds such as glutaraldehyde during cross-linking to prepare CLEAs.

Effect of hydrogen bond donor on the choline chloride-based deep eutectic solvent-mediated extraction of lignin from pine wood

In this work, twenty-five kinds of choline chloride (ChCl)-based deep eutectic solvents (DESs) containing acid, hydroxyl, amide, and binary hydrogen bond donors (HBDs) were prepared and successfully used to pretreat pine wood powder. As a result of the pretreatment, the glucan content in the pretreated biomass was increased, whereas the contents of hemicellulose and lignin were significantly decreased. The biomass pretreatment efficiency of the DESs had improved with increasing the polarity and hydrogen bond acidity (α) of the DESs. Among the studied DESs, ChCl:lactic acid:formic acid (1:1:1) with the highest α value was the most efficient DES in extracting lignin from biomass. The pretreated biomass also showed an enhanced enzymatic saccharification yield owing to the decreased particle size of the biomass and reduced content of hemicellulose and lignin. During the pretreatment process of biomass using DESs, the extracted lignin could be recovered successfully, with a yield of up to 60% and purity of over 90%. The molecular weight of the extracted lignin was much lower than that of the native cellulolytic enzyme lignin. The DES used for pretreatment process could be also successfully reused with high recovery yield of DES and high retention of delignification capacity.

Thermo-mechanical fractionation of yellow poplar sawdust with a low reaction severity using continuous twin screw-driven reactor for high hemicellulosic sugar recovery

Yellow poplar sawdust (YPS), a wood waste that can be easily collected from a local furniture factory, was fractionated using continuous twin screw-driven reactor for high hemicellulosic sugar recovery. The highest total sugar yields were attained under the following conditions: a barrel temperature of 127°C, sulfuric acid concentration of 0.8wt%, liquid feeding rate of 25mL/min, solid feeding rate of 2.0g/min, screw rotation speed of 25rpm, and residence time of 14.5min. The glucan and hemicellulose contents of the CTSR-fractionated YPS were 47.8% and 10.4%, respectively, and these results indicated that 44.9% of cellulose and 76.3% of the hemicellulose were extracted into liquid hydrolyzate. Meanwhile, the batch fractionation of YPS at the same reaction conditions showed a little fractionation effect, i.e., only 20.5% of hemicellulosic sugar yield was obtained.

Combined De-Algination Process as a Fractionation Strategy for Valorization of Brown Macroalga Saccharina japonica

A combined process, de-algination followed by enzymatic saccharification, was designed to produce alginate and glucose from Saccharina japonica consecutively. The process conditions of de-algination were optimized separately for each stage of acidification and alkaline extraction. Collectively, the de-algination yield was 70.1% under the following optimized conditions: 2.4 wt% of Na2CO3, 70 °C, and 100 min with the acidified S. japonica immersed in a 0.5 wt% H2SO4 solution for 2 h at room temperature. The glucan content in the de-alginated S. japonica increased to 38.0%, which was approximately fivefold higher than that of the raw S. japonica. The enzymatic hydrolysis of the de-alginated S. japonica almost completed in 9 h, affording 5.2 g (96.8% of glucan digestibility) of glucose at a de-alginated S. japonica loading of 14.2 g.

Low acid hydrothermal fractionation of Giant Miscanthus for production of xylose-rich hydrolysate and furfural

Low acid hydrothermal (LAH) fractionation was developed for the effective recovery of hemicellulosic sugar (mainly xylose) from Miscanthus sacchariflorus Goedae-Uksae 1 (M. GU-1). The xylose yield was maximized at 74.75% when the M. GU-1 was fractionated at 180°C and 0.3wt.% of sulfuric acid for 10min. At this condition, the hemicellulose (mainly xylan) degradation was 86.41%. The difference between xylan degradation and xylose recovery yield, i.e., xylan loss, was 11.66%, as indicated by the formation of decomposed products. The furfural, the value added biochemical product, was also obtained by 0.42g/L at this condition, which was 53.82% of furfural production yield based on the xylan loss. After then, the furfural production continued to increase to a maximum concentration of 1.87g/L, at which point the xylan loss corresponded to 25.87%.

Two-stage, acetic acid-aqueous ammonia, fractionation of empty fruit bunches for increased lignocellulosic biomass utilization

Fractionation of EFB was conducted in two consecutive steps using a batch reaction system: hemicellulose hydrolysis using acetic acid (AA; 3.0-7.0 wt.%) at 170-190°C for 10-20 min in the first stage, and lignin solubilization using ammonium hydroxide (5-20 wt.%) at 140-220°C for 5-25 min in the second stage. The two-stage process effectively fractionated empty fruit bunches (EFB) in terms of hemicellulose hydrolysis (53.6%) and lignin removal (59.5%). After the two-stage treatment, the fractionated solid contained 65.3% glucan. Among three investigated process parameters, reaction temperature and ammonia concentration had greater impact on the delignification reaction in the second stage than reaction time. The two-stage fractionation processing improved the enzymatic digestibility to 72.9% with 15 FPU of cellulase/g of glucan supplemented with 70 pNPG of β-glycosidase (Novozyme 188)/g-glucan, which was significantly enhanced from the equivalent digestibility of 28.3% for untreated EFB and 45.7% for AAH-fractionated solid.

Fractionation and delignification of empty fruit bunches with low reaction severity for high sugar recovery

Fractionation and delignification of empty fruit bunches (EFB) was conducted in a series of two steps under low reaction severity with the aim of minimizing the neutralization of hydrolyzates. In EFB underwent acid fractionation, the glucan content was increased to 62.4%, at which point 86.9% of the hemicellulosic sugar and 20.5% of the lignin were extracted from the raw EFB. Xylose-rich hydrolyzate, indicating a high selectivity of 17.7 could be separated. Through the consecutive delignification of acid-fractionated EFB using sodium hydroxide, solid residue with a high glucan content (70.4%) and low hemicellulosic sugar content (3.7%) could be obtained, which indicated that 95.9% of the hemicellulosic sugar and 67.5% of the lignin were extracted based on raw EFB. The final pretreated solid residue was converted to glucose through enzyme hydrolysis, which resulted in an enzymatic digestibility of 76.9% was achieved.

Acid-catalyzed hydrothermal severity on the fractionation of agricultural residues for xylose-rich hydrolyzates

The objective of this work was to investigate the feasibility of acid-catalyzed hydrothermal fractionation for maximum solubilization of the hemicellulosic portion of three agricultural residues. The fractionation conditions converted into combined severity factor (CS) in the range of 1.2-2.9. The highest hemicellulose yield of 87.88% was achieved when barley straw was fractionated at a CS of 2.19. However, the maximum glucose release of 15.29% was achieved for the case of rice straw. The maximum productions of various by-products were observed with the fractionation of rape straw: 0.88 g/L of 5-hydroxymethylfurfural (5-HMF), 2.16 g/L of furfural, 0.44 g/L of levulinic acid, 1.59 g/L of formic acid, and 3.06 g/L of acetic acid. The highest selectivities, a criterion for evaluating the fractionation of 21.55 for fractionated solid and 7.48 for liquid hydrolyzate were obtained from barley straw.

The influence of screw configuration on the pretreatment performance of a continuous twin screw-driven reactor (CTSR)

A combination of a continuous twin screw-driven reactor (CTSR) and a dilute acid pretreatment was used for the pretreatment of biomass with a high cellulose content and high monomeric xylose hydrolyzate. With the newly modified CTSR screw configuration (Config. 3), the influences of the screw rotational speed (30-60 rpm), of the pretreatment conditions such as acid concentration (1-5%) and reaction temperature (160-175 °C) at the operating condition of biomass feeding rate (1.0 g/min) and acid feeding rate (13.4 mL/min) on the pretreatment performance were investigated. The cellulose content in the pretreated rape straw was 67.1% at the following optimal conditions: barrel temperature of 165 °C, acid concentration of 3.0% (w/v), and screw rotational speed of 30 rpm. According to the three screw configurations, the glucose yields from enzymatic hydrolysis were 70.1%, 72.9%, and 78.7% for screw Configs. 1, 2, and 3, respectively.

Bioconversion of sawdust into ethanol using dilute sulfuric acid-assisted continuous twin screw-driven reactor pretreatment and fed-batch simultaneous saccharification and fermentation

Ethanol production from poplar sawdust using sulfuric acid-assisted continuous twin screw-driven reactor (CTSR) pretreatment followed by simultaneous saccharification and fermentation (SSF) was investigated. Pretreatment with high acid concentration increased the cellulose content in the pretreated solid (74.9-76.9% in the range of 4.0-5.5wt.% H(2)SO(4)). The sugar content (XMG; xylan+mannan+galactan) in the treated-solid was 11.1-15.2% and 0.9-5.7% with 0.5wt.% and 7.0wt.%, respectively. The XMG recovery yield of the sample treated with 4.0wt.% H(2)SO(4) at 185°C was maximized at 88.6%. Enzymatic hydrolysis test showed a cellulose digestibility of 67.1%, 70.1%, and 73.6% with 15, 30, and 45FPU/g-cellulose, respectively. In the fed-batch SSF tests with initial enzyme addition, the ethanol yield of each stage almost reached a maximum at 28h, 48h, and 56h, respectively, with yields of 63.9% (16.5g/L), 78.4% (30.1g/L), and 81.7% (39.9g/L), respectively.

Chemicals effect on the enzymatic digestibility of rape straw over the thermo-mechanical pretreatment using a continuous twin screw-driven reactor (CTSR)

Rape straw pretreated by a continuous twin screw-driven reactor (CTSR) with hot water presented a distinctive particle-size distribution profile as a function of the operating temperature. The relative amount of finer particle size dramatically increased as the ratio of solid to liquid was increased. Size reduction through physical CTSR process effectively promoted the enzymatic hydrolysis of pretreated rape straw. Meanwhile, the crystallinity of the physically pretreated straw was not a greater factor affecting the enzyme digestibility. The glucose conversion from the enzymatic hydrolysis of the straw pretreated by CTSR with hot water was maximized at 52%. Using the chemicals as catalyst have affected considerably for increasing the digestibility at same condition with hot water pretreatment. The enzymatic digestibilities of the straw pretreated by CTSR with sodium hydroxide and sulfuric acid were 60% and 77%, respectively.

Ethanol production from Saccharina japonica using an optimized extremely low acid pretreatment followed by simultaneous saccharification and fermentation

An extremely low acid (ELA) pretreatment using 0.06% (w/w) sulfuric acid at 170 °C for 15 min was employed to extract non-glucan components from Saccharina japonica, a brown macroalgae. Subsequent simultaneous saccharification and fermentation (SSF) was conducted using Saccharomyces cerevisiae DK 410362 and cellulase (15 FPU/g-glucan) and ß-glucosidase (70 pNPGU/g-glucan). Deionized water was used for making fermentation suspension. After the ELA pretreatment, a glucan content of 29.10% and an enzymatic digestibility of 83.96% was obtained for pretreated S. japonica. These values are 4.2- and 2.4-fold higher, respectively, than those of obtained with untreated S. japonica. In SSF, a bioethanol concentration of 6.65 g/L was obtained, corresponding to a glucose equivalent concentration of 13.01 g/L, which indicated an SSF yield of 67.41% based on the total available glucan of the pretreated S. japonica. The remaining separated liquid hydrolysate, which contains mannitol and alginate-derived oligosaccharides can be applied to other fermentations.

Behaviors of glucose decomposition during acid-catalyzed hydrothermal hydrolysis of pretreated Gelidium amansii

Acid-catalyzed hydrothermal hydrolysis is one path to cellulosic glucose and subsequently to its dehydration end products such as hydroxymethyl furfural (HMF), formic acid and levulinic acid. The effect of sugar decomposition not only lowers the yield of fermentable sugars but also forms decomposition products that inhibit subsequent fermentation. The present experiments were conducted with four different acid catalysts (H(2)SO(4), HNO(3), HCl, and H(3)PO(4)) at various acid normalities (0.5-2.1N) in batch reactors at 180-210 °C. From the results, H(2)SO(4) was the most suitable catalyst for glucose production, but glucose decomposition occurred during the hydrolysis. The glucose production was maximized at 160.7 °C, 2.0% (w/v) H(2)SO(4), and 40 min, but resulted in a low glucan yield of 33.05% due to the decomposition reactions, which generated formic acid and levulinic acid. The highest concentration of levulinic acid, 7.82 g/L, was obtained at 181.2 °C, 2.0% (w/v) H(2)SO(4), and 40 min.

Application of a continuous twin screw-driven process for dilute acid pretreatment of rape straw

Rape straw, a processing residue generated from the bio-oil industry, was used as a model biomass for application of continuous twin screw-driven dilute acid pretreatment. The screw rotation speed and feeding rate were adjusted to 19.7rpm and 0.5g/min, respectively to maintain a residence time of 7.2min in the reaction zone, respectively. The sulfuric acid concentration was 3.5wt% and the reaction temperature was 165°C. The enzymatic digestibility of the glucan in the pretreated solids was 70.9%. The continuous process routinely gave around 28.8% higher yield for glucan digestibility than did the batch processing method.

Two-stage acid saccharification of fractionated Gelidium amansii minimizing the sugar decomposition

Two-stage acid hydrolysis was conducted on easy reacting cellulose and resistant reacting cellulose of fractionated Gelidium amansii (f-GA). Acid hydrolysis of f-GA was performed at between 170 and 200 °C for a period of 0-5 min, and an acid concentration of 2-5% (w/v, H2SO4) to determine the optimal conditions for acid hydrolysis. In the first stage of the acid hydrolysis, an optimum glucose yield of 33.7% was obtained at a reaction temperature of 190 °C, an acid concentration of 3.0%, and a reaction time of 3 min. In the second stage, a glucose yield of 34.2%, on the basis the amount of residual cellulose from the f-GA, was obtained at a temperature of 190 °C, a sulfuric acid concentration of 4.0%, and a reaction time 3.7 min. Finally, 68.58% of the cellulose derived from f-GA was converted into glucose through two-stage acid saccharification under aforementioned conditions.

Optimization of fermentable sugar production from rape straw through hydrothermal acid pretreatment

Operational conditions for the hydrolysis of rape straw were optimized using the combined severity index (CS), which combines the effects of time, temperature, and acid concentration into a single parameter. The sugar recovery yield was 77.8% of the theoretical yield at a value of CS=1.3. A maximum concentration of xylose of 7.22 g/L was obtained when the straw was treated for 10 min at a low reaction temperature (150 °C) and high acid concentration (pH 1.17). The pentose-rich hydrolyzate exhibited a low concentration of fermentation-inhibiting compounds. The concept of CS can be conveniently and effectively applied for optimization of pretreatments.

Ethanol production from oil palm trunks treated with aqueous ammonia and cellulase

Oil palm trunks are a possible lignocellulosic source for ethanol production. Low enzymatic digestibility of this type of material (11.9% of the theoretical glucose yield) makes pretreatment necessary. An enzymatic digestibility of 95.4% with insoluble solids recovery of 49.8% was achieved after soaking shredded oil palm trunks in ammonia under optimum conditions (80°C, 1:12 solid-to-liquid ratio, 8h and 7% (w/w) ammonia solution). Treatment with 60 FPU of commercial cellulase (Accellerase 1000) per gram of glucan and fermentation with Saccharomyces cerevisiae D(5)A resulted in an ethanol concentration of 13.3g/L and an ethanol yield of 78.3% (based on the theoretical maximum) after 96 h. These results indicate that oil palm trunks are a biomass feedstock that can be used for bioethanol production.

Diffuse sclerosing variant of papillary carcinoma of the thyroid: ultrasound features with histopathological correlation

AIM

To evaluate the ultrasound (US) features of the diffuse sclerosing variant of papillary carcinoma (DSVPC) of the thyroid, with histopathological correlations.

MATERIALS AND METHODS

The US and histopathological findings of six patients with surgically proven DSVPC of the thyroid were retrospectively assessed.

RESULTS

Most of cases showed diffuse, scattered microcalcifications with or without associated masses and underlying heterogeneous hypoechogenicity at the site of the DSVPC in the thyroid. At ultrasound, scattered microcalcifications and heterogeneous hypoechogenicity seen in the DSVPC correlated to psammoma bodies and lymphocytic infiltration at histopathological review.

CONCLUSION

DSVPC of the thyroid usually manifested as diffuse scattered microcalcifications and associated suspicious mass on ultrasound. These findings are not specific for the DSVPC of the thyroid. However, in relatively young patients with suspicious masses associated with underlying diffuse scattered microcalcifications on US, the possibility of DSVPC should be included in differential diagnosis.

Intraoperative examination of sentinel lymph nodes by immunohistochemical staining in patients with breast cancer

AIM

To performed a prospective investigation of the relative merits of rapid cytokeratin immunohistochemical (CK-IHC) staining of the SLN removed during the operation of breast cancer patients.

STUDY DESIGN

Between December 2002 and March 2004, 62 patients with T1 and T2 breast cancer were enrolled after undergoing successful sentinel lymph node biopsy. Eighty-nine sentinel lymph nodes (mean number, 1.44) were biopsied and first examined by hematoxylin-eosin (H&E) stained frozen section. All the tumour free sentinel lymph nodes by H&E stained frozen section were immunostained for cytokeratin using a rapid immunohistochemical assay (Cytokeratin (PAN), 1:50, Novocastra Lab., Newcastle, UK) during the operations.

RESULTS

Rapid IHC staining revealed seven positive sentinel lymph nodes that were negative for metastasis by H&E staining. This study showed a sensitivity of 92.86%, a specificity of 100%, an accuracy of 98.9%, and a negative predictive value of 98.7%.

CONCLUSIONS

The intraoperative examination of sentinel lymph nodes is an accurate and effective way of predicting the axillary lymph node status of patients with breast cancers.

Migrated foreign body granulomas on mammography after injection in the cervicofacial area

AIM

The purpose of this study was to describe the mammographic findings of localized foreign body granulomas in women who were injected with a foreign body in the cervicofacial area to flatten wrinkles.

MATERIALS AND METHODS

The teaching files of our institutions were searched, and nine mammograms of migrated foreign body granulomas located. The mammograms were analysed, including the location, shape, size, distribution and depth of the high-density nodules. All these cases had undergone sonography.

RESULTS

The migrated foreign body granulomas appeared bilateral (n = 6) or unilateral (n = 3), as oval or round high-density nodules, in the upper inner and/or upper central locations. The average size of the lesions was less than 5 mm in all cases. All nine sonograms showed multiple, round cystic nodules, less than 5 mm in size, with strong posterior shadowing from far upper central to the upper inner breast. Sonography of the lower neck revealed the anatomy could not be visualized due to the strong posterior shadowing in the skin and subcutaneous fat layer.

CONCLUSION

Migrated foreign body granulomas appeared on mammograms as localized, multiple oval or round high-density nodules, less than 0.5 cm in size, in the upper inner and/or upper central breast. Breast sonography, including the sonography of the suspected cervicofacial area, is helpful in verifying migrated foreign body granulomas.

Improvement for the production of clavulanic acid by mutant Streptomyces clavuligerus

AIMS

To improve the production of clavulanic acid through the development of strains, the selection of a production medium and a pH shift strategy in a bioreactor.

METHODS AND RESULTS

Streptomyces clavuligerus mutant 15 was selected by antibacterial activities. As a result of pH control in a 2.5 l bioreactor, the highest productivity (3.37 microg x ml(-1) x h(-1)) was obtained at a controlled pH of 7.0.

CONCLUSIONS

The highest level of production obtained was an increase of about 36% compared with a non-controlled pH. When the production of clavulanic acid reached the maximum level, the pH was shifted from 7.0 to 6.0 for reduction in decomposition rate. The maximum concentration of clavulanic acid was maintained for 24 h as a result of the pH shift control, and a significant reduction in the decomposition of clavulanic acid was obtained.

SIGNIFICANCE AND IMPACT OF THE STUDY

Clavulanic acid decomposition was considerably reduced as a result of the pH shift control. The results of this study can be applied for the efficient production of beta-lactamase inhibitory antibiotics.

Imaging findings of metastatic disease to the breast

The purpose of this study was to evaluate imaging findings of metastatic disease to the breast. We analyzed 15 cases that had been previously examined by radiographic study (comprising a total of 11 mammograms, 13 ultrasounds and 3 chest CT). Primary malignancies included the following: 6 breast cancers, 5 stomach cancers, 2 melanomas, 1 cervical cancer, and 1 lung cancer. Radiologic findings were analyzed and the 15 cases were divided into two groups: hematogeneous and lymphangitic metastasis. Eleven cases were classified as lymphangitic metastasis (73.3%) and 4 cases were hematogeneous metastasis (26.7%). Multiple masses were shown in 13 cases (86.7%), and 12 cases displayed unilateral lesions (80%). There was no evidence of calcification. In the 11 cases with available mammogram, 7 cases (63.6%) revealed multiple masses with well-defined (2 cases, 28.6%) or ill-defined margin (5 cases, 71.4%) and 6 cases (54.5%) showed diffuse increased density and skin thickening. Among the 11 cases that revealed mass lesions on ultrasound, 2 cases showed a well-defined margin (18.2%) and 9 cases showed an ill-defined margin (81.8%). Posterior shadowing of the mass was seen in only 1 case. Four cases (36.3%) showed a minimal echogenic boundary around the mass. Eight cases showed diffuse skin thickening (53.3%). Three cases with chest CT showed multiple masses and/or diffuse skin and trabecular thickening of the breast. In conclusion, the characteristic imaging findings of metastatic disease to the breast are multiple ill-defined masses with a lack of desmoplastic reaction and no calcification, as compared to primary breast carcinoma. The diffuse lesions without evidence of breast mass on mammogram and US could be distinguishable from inflammatory carcinoma of breast origin.

Sonographic findings of metastatic disease to the thyroid

The goal of this study was to evaluate the sonographic findings of thyroid metastases arising from non-thyroid primaries. The study over a 5-year period comprised nine patients who had histopathologically proven metastatic disease to the thyroid. Ultrasonography was available in all cases. Ultrasound-guided needle aspiration was performed on 10 suspected nodules as determined by ultrasound. The Ultrasonographic findings were analyzed in two different ways. The first analysis included only those nodules biopsed, and the second analysis included all the nodules, biopsed and non-biopsed. The primary neoplasms were breast carcinoma (n=6), uterine leiomyosarcoma (n=1), cervical carcinoma (n=1), and nasopharyngeal carcinoma (n=1). Excluding 2 nodules, the 8 remaining metastatic nodules exhibited ill-defined hypoechoic character with heterogeneous texture. The other two nodules showed relatively circumscribed iso- or hypo-echoic character with cystic portion. From the analysis of ultrasonographic findings including all thyroid nodules irrespective of pathologic proof, 7 cases - excluding the 2 cases from the 9 cases - showed unilateral or bilateral multiple nodules suspected of metastasis. There was no evidence of microcalcification in any thyroid nodules. In conclusion, the sonographic findings of the thyroid metastatic nodules were not specific, but unilateral or bilateral multiple suspected thyroid nodules without evidence of microcalcification may be suggestive of metastatic nodules among patients with a known primary non-thyroidal tumor.

Enhancement of cephalosporin C production by cultivation of Cephalosporium acremonium M25 using a mixture of inocula

AIMS

To enhance the productivity of Cephalosporin C (CPC) by cultivation of Cephalosporium acremonium M25 using a mixture of inocula.

METHODS AND RESULTS

Inoculum age was classified into three stages (early, intermediate and late) by image analysis. A mixture of inocula, according to the inoculum ages, was used for efficient production of CPC in the main culture. The most effective mixing ratio of inocula for CPC production in shake flasks was a 3 : 7 volume ratio of early- and late-stage inocula. This was also the case in a 1.5 l stirred-tank reactor. CPC productivity was enhanced by about 32% and 34% when using an inoculum mixture in the shake flask and 1.5 l stirred-tank reactor, respectively.

CONCLUSION

The morphological characteristics of C. acremonium M25 in the seed culture were quite different according to inoculum age. The compromise of different ages of inoculum showed better production of CPC.

SIGNIFICANCE AND IMPACT OF THE STUDY

The productivity of CPC was enhanced considerably when using mixed inocula. The results of this study can be applied to fungal cultures for efficient production of various metabolites.

Radiologic findings of metastatic signet ring cell carcinoma to the breast from stomach

Two Korean women (41 and 23-years of age) presented with painful breast enlargement and redness. The involved breast was confirmed as metastatic signet ring cell carcinoma. Although metastatic signet ring cell carcinoma of the breast shows similar clinical symptoms to inflammatory breast cancer, the difference between the two is that this malignancy showed no microcalcifications or mass on radiographic findings (mammograms and US). Therefore, after the confirmation of signet ring cell carcinoma of the breast has been made, metastatic signet ring cell carcinoma should be considered if there are no microcalcifications or masses evident on radiographic findings.

Bioconversion of cellulose into ethanol by nonisothermal simultaneous saccharification and fermentation

The kinetic characteristics of cellulase and beta-glucosidase during hydrolysis were determined. The kinetic parameters were found to reproduce experimental data satisfactorily and could be used in a simultaneous saccharification and fermentation (SSF) system by coupling with a fermentation model. The effects of temperature on yeast growth and ethanol production were investigated in batch cultures. In the range of 35-45 degrees C, using a mathematical model and a computer simulation package, the kinetic parameters at each temperature were estimated. The appropriate forms of the model equation for the SSF considering the effects of temperature were developed, and the temperature profile for maximizing the ethanol production was also obtained. Briefly, the optimum temperature profile began at a low temperature of 35 degrees C, which allows the propagation of cells. Up to 10 h, the operating temperature increased rapidly to 39 degrees C, and then decreased slowly to 36 degrees C. In this nonisothermal SSF system with the above temperature profile, a maximum ethanol production of 14.87 g/L was obtained.

Granular cell tumor of the breast

We report a case of granular cell tumor of the breast presenting as a spiculated lesion mimicking carcinoma on mammography and ultrasonography (US).

Lobular carcinoma in situ in sclerosing adenosis

The initial presentation of breast malignancy as noninvasive carcinoma in an area of sclerosing adenosis is unusual. Especially, lobular carcinoma in situ in sclerosing adenosis sometimes can be a potential source of confusion with invasive lobular carcinoma. We report a case of lobular carcinoma in situ presenting in adenosis exhibiting patterns akin to invasive lobular carcinoma, thus leading to potential misdiagnosis. Overall architecture of the lesion as seen at lower power and immunohistochemistry can be useful to distinguish between sclerosing adenosis with lobular carcinoma in situ and infiltrating lobular carcinoma.

Significance of follow-up mammography in estimating the effect of tamoxifen in breast cancer patients who have undergone surgery

OBJECTIVE

We evaluated mammographic changes to assess the effect of tamoxifen in breast cancer patients who had undergone surgery.

MATERIALS AND METHODS

We reviewed the mammograms of 102 breast cancer patients treated with tamoxifen (20 mg per day); these patients were subgrouped into tamoxifen-only patients and patients treated with tamoxifen in combination with another therapy (chemotherapy, radiotherapy, or both). The control group was made up of 50 breast cancer patients who did not undergo tamoxifen therapy and 20 healthy women who had an age distribution and menstruation status similar to those of the breast cancer patients. Two radiologists evaluated parenchymal patterns on mammograms of the contralateral breast in the breast cancer patients and of the left breast in the healthy women. Parenchymal changes before and after surgery were also analyzed.

RESULTS

Follow-up mammography showed decreased breast parenchyma in 59.8% of the tamoxifen group, 87.0% of the premenopausal tamoxifen-treated women, 36.0% of the nontamoxifen patients, and 10.0% of the healthy women.

CONCLUSION

On follow-up mammography of breast cancer patients, breast parenchyma was shown to be decreased after tamoxifen therapy. Mammography can be a useful method for evaluating breast parenchymal changes after tamoxifen treatment.

Imaging of tuberculous disease involving breast

The aim of our study was to evaluate radiologic findings of the tuberculosis involving breast. We evaluated the radiologic features of 17 patients (18 lesions) with tuberculous disease involving the breast. The radiologic examinations, including mammography (16 patients), ultrasonography (12 patients), and Gd-DTPA-enhanced dynamic MRI (6 patients), were analyzed. Mammographic findings included mass (12 of 17 lesions), calcification (3 of 17 lesions), asymmetric density with spiculated margin (5 of 17 lesions), and axillary lymph node enlargement (8 of 17 lesions). On ultrasonography, a smooth bordered mass (7 of 13 lesions) with thin boundary (7 of 13 lesions) and heterogeneous, intermediate internal echoes (9 of 13 lesions) were most commonly demonstrated. On Gd-DTPA-enhanced dynamic MRI, 3 lesions showed significant enhancement at the first minute after injection (3 of 7 lesions). The maximum enhancing amount was greater than 500 normalized units, and the enhancing pattern was smooth or irregular ring appearance. Breast involvement with tuberculosis is rare but should be considered in the differential diagnosis of a woman living in an endemic area or when extramammary foci of tuberculosis are present. A multimodality imaging approach with clinical evaluation will help to establish the diagnosis of tuberculosis involving breast.

Mucoepidermoid carcinoma of the salivary gland--a clinico-pathologic and immunohistochemical study for c-erbB-2 oncoprotein

Twenty-five cases of mucoepidermoid carcinoma of the salivary glands were studied with respect to clinico-pathologic features, prognostic factors, and c-erbB-2 oncoprotein expression. Fourteen cases were located in parotid glands, 2 in submandibular glands and 9 in minor salivary glands. Fourteen patients were confirmed to have local recurrences, 6 patients manifested systemic metastases, and 10 patients died of the disease. They were histologically graded as I in 5, II in 12 and III in 8 cases respectively, and the histologic grade was significantly correlated with disease-free interval and overall survival of the patients. c-erbB-2 overexpression was observed in 9 cases (36%), with a trend to be associated with the higher grade, but was not evaluated as a significant survival-related factor in this series. Larger size and major gland location of the tumors were correlated with more frequent regional lymph node metastases. The present study showed that c-erbB-2 overexpression was not uncommonly present in mucoepidermoid carcinoma of the salivary glands, especially of higher grade, and the histologic grade was the most important and handy prognostic indicator.

Breast conserving therapy in stage I & II breast cancer in Korea

A randomized clinical study of 187 patients with T1, T2 breast cancer was performed, in order to compare the effects of modified radical mastectomy (MRM) and breast conserving therapy (BCT) on breast recurrence, overall survival, and disease-free survival. One hundred eighty seven patients with T1, T2 breast cancer, admitted at Yongdong Severance Hospital from April 1991 to August 1994, were randomized into two different treatment groups. Of the 187 patients, 111 patients had received MRM and 76 had received BCT. In any of the variables considered with the exceptions of age and menopausal status, patient characteristics such as tumor size, incidence of axillary lymph node metastasis, histologic grading, and estrogen and progesterone receptor positive rate were not significantly different between the two groups (p < 0.05). Using the Kaplan-Meier Product-limit method and log-rank test, the difference of locoregional recurrence, and overall and disease-free survival, between these comparable groups was analyzed. Average follow-up period was 37.6 months. Two out of 111 MRM patients and two out of 76 BCT patients had locoregional recurrence. Only one patient who had MRM was found to have a recurrence in her opposite breast. The overall survival rates in MRM and BCT patients were, respectively 93.7% and 94.1%. Furthermore, the disease-free survival rates were, respectively, 89.2% and 93.9%. This result indicates that there were no significant differences between two groups in locoregional recurrence, and overall and disease-free survival. Having gained a better cosmetic appearance, the conservative treatment group was satisfied with the BCT. In this study, we conclude that BCT is a good alternative surgical treatment modality for T1, T2 Korean breast cancer patients, which could substitute for the more traditional MRM. However, further follow-up will be needed for long-term results.

Partial mastectomy with axillary lymph node dissection and radiotherapy as a new treatment modality of breast cancer (I)

This is the first preliminary report among two consecutive papers. Partial mastectomy(PM), axillary lymph node dissection(AD) and radiotherapy (RT) were performed on seventeen operable breast cancer patients who had been admitted from April 1991 to March 1992 to the department of surgery, Yongdong Severance Hospital for improved cosmetic appearance and better survival rate. Of seventeen patients, 47% were T1 lesion and 76% were stage I and II. Extensive intraductal component(EIC) within or around the tumor was also analyzed. Twenty nine per cent of the patients were EIC positive. The mean number of axillary lymph nodes was 21.5 after PM with AD and 20.5 after mastectomy. For radiotherapy, 4,500 rad was delivered to the breast parenchyma and 1,600 rad of boost to the primary tumor site using the electron beam method after surgery. All patients have since been living well without any local recurrence and were satisfied with breast preservation for the one-year follow-up period. We concluded that the PM, AD and RT can be another surgical treatment modality of breast cancer. A longer follow-up data will be followed on the second paper.

Congenital glioblastoma multiforme--report of an autopsy case

A congenital neoplasm arising in the central nervous system is rarely encountered, and the majority of case reports that have dealt with intracranial tumors have been divided almost equally between teratomas and various gliomas. We experienced a rare case of congenital glioblastoma multiforme encountered in a three day-old male infant who presented with hydrocephalus since birth. Post-mortem examination revealed that the tumor seemed to have originated from the right thalamic region extending centrifugally to the cerebral cortex and through the brain-stem down to the cerebellum.

The role of mammography on breast cancer patients in a hospital setting

From Oct. 1, 1983 to May 31, 1988, 6198 mammograms were taken and 443 mastectomies were performed at the Yonsei University Hospital, Seoul, Korea. Of these, 191 cases had preoperative mammography performed prior to surgery (study group) and 252 cases underwent mastectomies without preoperative mammography (control group). There were no significant differences between the two groups in pathological stages, axillary lymph node metastasis and size of the tumor, suggesting that little benefit is derived from the preoperative mammography in the hospital setting. However, there were a number of other findings, including a 14% incidence of multiple foci and localization of non-palpable cancer in 3% of cases, that could help us to make therapeutic plans and strategies for these patients.