A novel thermoacidophilic cellulase from Alicyclobacillus acidocaldarius

A novel cellulase was isolated from the thermoacidophilic bacterium Alicyclobacillus acidocaldarius ATCC27009 grown in medium containing carboxymethylcellulose. The enzyme is a glycosylated monomer of 56.2 kDa, relatively thermostable, with optimal pH and temperature of 4.0 and 65 degrees C, respectively. Enzymatic assays on several polysaccharides demonstrated that CelG was specific for carboxymethylcellulose.

Hydrolysis of xylan at high temperature by co-action of the xylanase from Anoxybacillus flavithermus BC and the beta-xylosidase/alpha-arabinosidase from Sulfolobus solfataricus Oalpha

AIMS

It is evaluated the effectiveness of the combined action of two highly thermostable enzymes for the hydrolysis of xylans at high temperature in order to produce D-xylose.

METHODS AND RESULTS

Xylans from different sources were hydrolyzed at high degree at 70 degrees C by co-action of a xylanase from the thermophilic bacterium Anoxybacillus flavithermus BC and the novel beta-xylosidase/alpha-arabinosidase from the hyperthermophilic crenarchaeon Sulfolobus solfataricus Oalpha. Beechwood xylan was the best substrate among the xylans tested giving, by incubation only with xylanase, 32.8 % hydrolysis after 4 h. The addition of the beta-xylosidase/alpha-arabinosidase significantly improved the rate of hydrolysis, yielding 63.6% conversion after 4 h incubation, and the main sugar identified was xylose.

CONCLUSIONS

This study demonstrates that a significant degree of xylan degradation was reached at high temperature by co-action of the two enzymes. Xylose was obtained as a final product in considerable yield.

SIGNIFICANCE AND IMPACT OF THE STUDY

Although the xylan represents the second most abundant polysaccharide in nature, it still doesn't have significant utilization for the difficulties encountered in its hydrolysis. Its successful hydrolysis to xylose in only one stage process could make of it a cheap sugar source and could have an enormous economic potential for the conversion of plant biomass into fuels and chemicals.

Effects of two years of growth hormone (GH) replacement therapy on bone metabolism and mineral density in childhood and adulthood onset GH deficient patients

The aim of the current study was to evaluate bone metabolism and mass before and after 2 years of GH replacement therapy in adults with childhood or adulthood onset GH deficiency. Thirty-six adults with GH deficiency, 18 with childhood onset, 18 with adulthood onset GH deficiency and 28 sex-, age-, height- and weight-matched healthy subjects entered the study. Biochemical indexes of bone turnover such as serum osteocalcin, serum carboxyterminal telopeptide of type-I procollagen, urinary hydroxyproline/creatinine and deoxypyridinoline/creatinine, of soft tissue formation such as aminoterminal propeptide of type-III and bone mineral density were evaluated. Childhood onset GH deficient patients had significantly decreased bone (osteocalcin: 2.5+/-1.3 vs 6.6+/-4.8 mcg/l, p<0.001) and soft tissue formation (aminoterminal propeptide of type III: 273+/-49 vs 454+/-23 U/I, p<0.001) indexes and normal bone resorption indexes (serum carboxyterminal telopeptide of type-I procollagen: 105+/-48 vs 128+/-28 mcg/l p=NS; urinary hydroxyproline/creatinine: 0.19+/-0.16 vs 0.28+/-0.16 mmol/mol, p=NS; urinary deoxypyridinoline/creatinine: 21 +/-10 vs 25+/-8 mcmol/mol, p=NS) compared to healthy subjects. On the contrary, no significant difference in bone turnover indexes between adulthood onset GH deficient patients and healthy subjects was found. Moreover, significantly decreased bone mineral density at any skeletal site and at whole skeleton was found in GH deficient patients compared to healthy subjects (e.g. femoral neck: 0.74+/-0.13 vs 0.97+/-0.11 g/cm2, p<0.001). In addition, a significant reduction of bone mineral density was found in childhood compared to adulthood onset GH deficient patients at any skeletal site, except at femoral neck. After 3-6 months of treatment, both groups of patients had a significant increase in bone turnover and in soft tissue formation. In particular, in childhood onset GH deficient patients after 3 months osteocalcin increased from 2.5+/-1.3 to 7.9+/-2.1 mcg/l, p<0.001 aminoterminal propeptide of type-III from 273+/-49 to 359+/-15 U/I p<0.001; serum carboxyterminal telopeptide of type-I procollagen from 105+/-48 to 201+/-45 mcg/l, p<0.001; urinary hydroxyproline/creatinine from 0.19+/-0.16 to 0.81+/-0.17 mmol/mol, p<0.001; urinary deoxypyridinoline/creatinine from 21 +/-10 to 54+/-20 mcmol/mol, p<0.001; while in adulthood onset GH deficient patients after 6 months osteocalcin increased from 4.2+/-3.6 to 6.5+/-1.9 mcg/l, p<0.05; aminoterminal propeptide of type- III from 440+/-41 to 484+/-37 U/I, p<0.05; serum carboxyterminal telopeptide of type-I procollagen from 125+/-40 to 152+/-22 mcg/l, p<0.05; urinary hydroxyproline/creatinine from 0.24+/-0.12 to 0.54+/-0.06 mmol/mol, p<0.001; urinary deoxypyridinoline/creatinine from 23+/-8 to 42+/-5 mcmol/mol, p<0.001. No significant difference in bone turnover between pre- and post-treatment period was found after 18-24 months of GH therapy. Conversely, bone mineral density was slightly reduced after 3-6 months of GH therapy, while it was significantly increased after 18-24 months. In fact, femoral neck bone mineral density values significantly rose from 0.74+/-0.13 g/cm2 to 0.87+/-0.11 g/cm2 (pre-treatment vs 2 years of GH treatment values). In conclusion, patients with childhood or adulthood onset GH deficiency have osteopenia that can be improved by long-term treatment with GH.

[Modifications in diagnosis and therapy of osteoporosis after bone densitometry]

The cost-benefit ratio of diagnostic procedures has become a major problem: in particular, the expense of computerized bone mineral densitometry for osteoporosis diagnosis has brought this issue to public attention. To avoid a procedure considered costly, non-specialists often rely on standard radiography alone for diagnosis. In this study, we evaluated the percent of cases in which densitometry modified diagnosis and therapy based solely on radiographic findings. Over a 10-month period, we recruited 133 consecutive post-menopausal patients (average age 58.3 years, average time since menopause 12 years) who had never undergone densitometry. Bone density at the lumbar (L1-L4) or femoral (non-dominant) level was measured with dual energy X-ray absorptiometry. The average time between densitometry and the last radiographic examination was 13.6 months. Ninety-one patients (68.4%) had a change in diagnosis following densitometry. In 42 cases (31.6%), the previous diagnosis remained unchanged (prevalence ratio 2.2; 95% confidence interval 1.6 to 2.7). Therapy was changed in 75.2% of the cases (100 patients) and remained the same in 24.8% (33 patients; prevalence ratio 3.0; 95% confidence interval 2.3 to 3.7). Our data underscore the importance of densitometry in yielding quantitative data that are utilizable during follow-up and able to support osteoporosis diagnosis and therapy.

Effects of dietary treatment on bone mineral density in adults with celiac disease: factors predicting response

OBJECTIVE

Conflicting evidence is reported about the effect of treatment on bone mineral density (BMD) in adults with celiac disease (CD). This study analyzed the effects on BMD induced by treatment with a calcium-rich, gluten-free diet in adults with nonsilent CD.

METHODS

In 30 women and 11 men with newly diagnosed CD, BMD was measured at the right femur (femoral neck and right Ward's triangle) and the lumbar spine by dual-energy x-ray absorptiometry under untreated conditions (pretreatment) and after 1-yr treatment with a calcium-rich, gluten-free diet.

RESULTS

On average, posttreatment BMD was greater than pretreatment BMD at the lumbar spine (mean +/- SE: 0.907 +/- 0.028 and 0.795 +/- 0.028 g/cm2, respectively; p < 0.001), the femoral neck (0.818 +/- 0.023 and 0.741 +/- 0.030 g/cm2, respectively; p = 0.002), and the Ward's triangle (0.703 +/- 0.025 and 0.654 +/- 0.025 g/cm2, respectively; p < 0.001). The greatest BMD change (percent of baseline) was observed at the lumbar spine (+14.1%), the smallest at the Ward's triangle (+7.5%). In the absence of appropriate controls, the BMD change expected in the patients under untreated conditions was estimated by regressing pretreatment BMD over duration of CD with control for gender and age at which CD became clinically evident. The regression coefficient of this analysis indicated that 1 yr of untreated CD was associated with a BMD decrease at the lumbar spine by 0.00570 g/cm2 (95% confidence interval -0.0103 to -0.0011 g/cm2). The 95% confidence interval of the treatment-induced change in BMD at the lumbar spine (+0.060 to +0.160 g/cm2) did not overlap the 95% confidence interval of the BMD change expected under untreated conditions. A large interindividual variability was observed in the BMD response to the treatment: in univariate and multivariate analyses, the treatment-induced change in BMD was significantly related to gender (greater in women than in men) and to pretreatment age and BMD.

CONCLUSIONS

The data show that BMD is increased by dietary treatment of CD in most but not all adult patients; pretreatment BMD, gender, and pretreatment age predict the bone response after a 1-yr treatment.

[The determinants of bone mineral density in hemiplegic patients. Preliminary data]

We studied a group of hemiplegic patients to determine the amount of bone loss of the paretic versus the normal limb and to evaluate the importance of several variables in determining this difference. Thirty consecutive subjects with hemiplegia caused by a cerebral vascular accident were studied: 15 postmenopausal women (average age 65.1 years) and 15 men (average age 58.3 years) (average age of entire group, 63.2 years; age range of entire group, 27-84 years). The mean duration of immobilization was 7.7 months for women (range 1-40 months) and 10.5 months for men (range 1-48 months). All subjects had a complete physical examination, underwent bilateral femoral neck DEXA, and filled out a questionnaire. The percent difference (delta) between the paretic and normal limb was 6.1% in the women and 3.8% in the men. Logistic regression analysis, after control for age and sex, indicated that the degree of demineralization depended significantly and directly on the duration of immobilization and depended inversely on the time elapsed since menopause. Our data evidence the importance of immobilization osteoporosis and point to the role of hormonal factors in its pathogenesis.

Iodine-131 metaiodobenzylguanidine scintigraphy for localization of lesions in children with neuroblastoma: comparison with computed tomography and ultrasonography

Iodine-131 metaiodobenzylguanidine (MIBG) scintigraphy, computed tomography (CT) and ultrasonography (US) were used to localize tumour lesions in 28 children with histologically proven neuroblastoma. Overall, a total of 73 lesions were detected on imaging studies. MIBG scintigraphy, CT and US localized 63 (86%), 49 (67%) and 36 (49%) of these lesions, respectively. The findings of the three imaging techniques were concordant in respect of only 31 (42%) of the lesions. The best agreement among MIBG scintigraphy, CT and US was observed for abdominal lesions (the techniques were concordant for 22 of 23 lesions, i.e. 96%). MIBG scintigraphy detected nine out of ten (90%) liver metastases, but agreement with CT and US was observed in only six instances (60%). The imaging findings were concordant in respect of only two (33%) out of six lymph node metastases; the MIBG scan was normal in the other four cases. Imaging agreement was observed for a lesion located in the pelvis. MIBG and CT findings were concordant in four lesions located in the chest, but US was not performed. MIBG scintigraphy depicted the majority (96%) of the skeletal lesions (23/24); CT showed five of these, but, again, US was not performed. The imaging findings were not concordant as regards the remaining five lesions located in different anatomical sites. The results indicated that MIBG imaging is more sensitive that CT and US in localizing the majority of neuroblastoma lesions. Since the metastatic spread of neuroblastoma is unpredictable, we recommend MIBG scintigraphy as the initial imaging modality for staging of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[131I-meta-iodobenzylguanidine scintigraphy in patients with a suspected pheochromocytoma. A comparison with CT and biohumoral parameters]

The results of 131I metaiodobenzylguanidine (MIBG) and Computed Tomography (CT) scans in a group of patients with clinically suspected pheochromocytoma were evaluated and compared with biohumoral parameters. We studied 24 consecutive patients (7 M and 17 F; age range 20-66 years). 131I-MIBG scintigraphy and CT were in agreement in 19 patients (79%): of them 7 cases were true positive, and 12 were true negative. Disagreement between the two imaging techniques was observed in 5 patients (21%). In this group, one patient, with positive CT scan, had false negative MIBG study, while 4 patients with negative MIBG scan, had false positive CT. MIBG showed significantly higher (p less than 0.05) specificity (100%), positive predictive value (100%), and accuracy (96%) than CT (75%, 67%, and 83%, respectively). 131I-MIBG scintigraphy is an accurate, noninvasive technique for localizing pheochromocytoma and providing direct tissue characterization, while CT provides more accurate spatial information. In conclusion, CT and MIBG studies are complementary in the evaluation of patients with suspected pheochromocytoma.

[The 75-seleno-homocholic acid-taurine test (SeHCAT). A useful method for detecting the idiopathic malabsorption of bile salts in chronic functional diarrhea]

The 75-SeHCAT test has been used for identifying, within a group of patients with chronic functional diarrhea, a subgroup of cases with ileal bile acid malabsorption. Thirty-four subjects were studied: 10 healthy subjects and 24 patients with chronic functional diarrhea. Findings are expressed as percentage of basal abdominal radioactivity after 7 days. Normal values in our control subjects were: over 25% on day 4 and over 10% on day 7. Pathological results were found in 9 of 24 patients (37.5%) on day 4 and of 24 patients (41.7%) on day 7. A significant correlation was found between the percentages of retention on days 4 and 7 (p less than 0.001). In SeHCAT-positive patients cholestyramine administration led to clinical improvement. According to our experience, the SeHCAT test is a useful tool for the evaluation of bile acid malabsorption in the differential diagnosis of chronic functional diarrhea.

Pre-operative axillary lymphoscintigraphy in breast cancer: experience with sub-areolar injection of 99Tcm-nanocolloidal albumin

Thirty-two patients affected by monolateral breast cancer and five patients with benign mammary pathology were submitted to pre-operative lymphoscintigraphy by sub-areolar injection of nanocolloidal albumin with the aim of evaluating any axillary lymphonodular involvement. The 32 patients, affected by cancer, subsequently underwent a surgical operation so as to permit a pathological-anatomical study of the axillary cavity. A comparison between the clinical and instrumental examinations brought to light the much greater reliability of the latter which gave 87.5% of correct diagnoses. The authors emphasize the absence of false positive results and the excellent sensitivity of the method in bringing to light even limited involvements of the axillary lymphonodes. The authors believe that axillary lymphoscintigraphy deserves to be included in the pre-operative protocols which afford a correct staging of the disease and, consequently, a better assessment of the extent of the surgical action.