[Open hepatectomy versus laparoscopic in the treatment of primary left-sided hepatolithiasis: a propensity, long-term follow-up analysis at a single center].

To compare short-term and long-term efficacy after laparoscopic left hepatectomy(LLR) to open left hepatectomy(OLH) for primary left-sided hepatolithiasis. Methods: Clinical data of 187 patients with left-sided hepatolithiasis and underwent laparoscopically or open left-sided hepatectomy from October 2014 to October 2019 at the Second Affiliated Hospital of Anhui Medical University were retrospectively analyzed in this propensity score matching (PSM) study and were matched in terms of age, sex, body mass index, liver function, ASA score, comorbidities, history of biliary surgery, and smoking history on the ratio of 1∶1.There were 47 cases in each group and the mean age were (54.7±12.3)years old(range:34 to 75 years old) and (53.2±12.6) years old (range: 34 to 75 years old) in open and laparoscopically group respectively. The data of operation time, intraoperative blood loss, postoperative hospital-stay, complication rate, biliary fistula rate, stone clearance rate, and stone recurrence rate were compared. The quantitative data were compared using t-test or rank-sum test. Count data were analyzed with χ(2) test or Fisher test. Results: No significant difference was observed in the clinical characteristics of included 94 patients in this study(all P>0.05).The length of the postoperative hospital-stay after OLH was significantly higher than that in the LLH group((10.8±3.1) days vs.(8.5±2.2)days, t=4.085, P=0.000). LLR significantly decreased the incidence of postoperative biliary fistula compared with the OLH (6.3% vs.21.2%, χ(2)=4.374, P=0.036) and the rates of postoperative complications in the OLH group was significantly higher than that in the LLH group (48.9% vs.27.6%, χ(2)=4.502, P=0.034). Moreover, the stone recurrence rates in the LLH group was significantly lower than that after OLR (4.2% vs. 17.0%, χ(2)=4.029, P=0.045). OLH (95% CI: 1.55 to 10.75, P=0.004) and postoperative complications (95% CI: 1.29 to 9.52, P=0.013) were independent risk factors for prolonged hospital stay. OLH (95% CI: 1.428 to 44.080, P=0.018) and residual stones (95% CI: 1.580 to 62.379, P=0.014) were independent risk factors for the occurrence of postoperative biliary fistula. Biliary fistula (95% CI: 1.078 to 24.517, P=0.040) was an independent risk factor for the recurrence of stones. Conclusion: Compared with OLH, LLH is safe and effective for the treatment of the primary left-sided hepatolithiasis with the clinical benefits of shorter hospital stay, fewer morbidity and biliary fistula occurrence, and lower stone recurrence rates.

Defining SNAP by cross-sectional and longitudinal definitions of neurodegeneration.

Introduction: Suspected non-Alzheimer's pathophysiology (SNAP) is a biomarker driven designation that represents a heterogeneous group in terms of etiology and prognosis. SNAP has only been identified by cross-sectional neurodegeneration measures, whereas longitudinal measures might better reflect "active" neurodegeneration and might be more tightly linked to prognosis. We compare neurodegeneration defined by cross-sectional 'hippocampal volume' only (SNAP/L-) versus both cross-sectional and longitudinal 'hippocampal atrophy rate' (SNAP/L+) and investigate how these definitions impact prevalence and the clinical and biomarker profile of SNAP in Mild Cognitive Impairment (MCI). Methods: 276 MCI patients from ADNI-GO/2 were designated amyloid "positive" (A+) or "negative" (A-) based on their florbetapir scan and neurodegeneration 'positive' or 'negative' based on cross-sectional hippocampal volume and longitudinal hippocampal atrophy rate. Results: 74.1% of all SNAP participants defined by the cross-sectional definition of neurodegeneration also met the longitudinal definition of neurodegeneration, whereas 25.9% did not. SNAP/L+ displayed larger white matter hyperintensity volume, a higher conversion rate to dementia over 5 years and a steeper decline on cognitive tasks compared to SNAP/L- and the A- CN group. SNAP/L- had more abnormal values on neuroimaging markers and worse performance on cognitive tasks than the A- CN group, but did not show a difference in dementia conversion rate or longitudinal cognition. Discussion: Using a longitudinal definition of neurodegeneration in addition to a cross-sectional one identifies SNAP participants with significant cognitive decline and a worse clinical prognosis for which cerebrovascular disease may be an important driver.

Bio-syncretic tweezers actuated by microorganisms: modeling and analysis.

Advancements in micro-/nano-technology have led to the development of micro-manipulators. However, some challenges remain; for instance, the efficiency, precision and flexibility of micro-manipulators restrain their applications. This paper proposes a bio-tweezer system to flexibly manipulate micro-objects with bio-actuation via local light-induced high-concentration microorganisms in two different manipulation modes: light-spot induced mode and geometric shape-induced mode. Depending on the shape of micro-objects, either 2-dimensional translation or 1-dimensional rotation can be achieved. Based on the Langevin equation, a mathematical model considering both hydrodynamics and mimicked Brownian motion is proposed to analyze the bio-manipulation performance of the microorganisms; the model was validated by experiments to translate micro-particles in a two-dimensional plane and to rotate a micro-gear structure around its axis. This paper will aid in the development of micro-manipulators and the quantitative understanding of micro-/nano-manipulation actuated by microorganisms.

Longitudinal changes in cognition in early Parkinson's disease patients with REM sleep behavior disorder.

INTRODUCTION: Cognitive decline is common in Parkinson's disease (PD), and identifying patients at highest risk for it is essential. We aimed to examine the effect of possible REM sleep behavior disorder (pRBD) on rate of cognitive decline in early PD, for both global cognition and in specific cognitive domains. METHODS: Parkinson's Progression Markers Initiative (PPMI) is a multi-site, international study of PD patients untreated at enrollment. pRBD was assessed with the REM sleep behavior disorder questionnaire (RBDSQ). Global cognition was assessed at baseline and annually using the Montreal Cognitive Assessment (MoCA) and a cognitive battery. Linear mixed effects models were used to examine the relationship between pRBD (RBDSQ≥6) and rate of change in cognitive variables. Age, sex, years of education, and baseline motor and cognitive scores were included as covariates. RESULTS: The baseline sample consisted of 423 individuals with PD, mean age 61.7 years and 65.5% male. Data was available on 389, 366, and 196 participants at 1-year, 2-year, and 3-year follow-up respectively. Possible RBD occurred in 108 (25.5%) at baseline. In multivariate analyses, baseline RBD was associated with greater annual rate of decline in MoCA score (ß = -0.34, 95%CI -0.54, -0.13, p < 0.001), Symbol Digit Modalities Test (ß = -0.69, 95%CI -1.3, -0.09, p = 0.024), and Hopkins Verbal Learning Test-Revised, delayed free recall (ß = -0.21, 95%CI -0.41, -0.013, p = 0.037). CONCLUSIONS: Possible RBD is common in early PD and predicts future cognitive decline, particularly in attention and memory domains.

Plasma biomarkers of depressive symptoms in older adults.

The pathophysiology of negative affect states in older adults is complex, and a host of central nervous system and peripheral systemic mechanisms may play primary or contributing roles. We conducted an unbiased analysis of 146 plasma analytes in a multiplex biochemical biomarker study in relation to number of depressive symptoms endorsed by 566 participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI) at their baseline and 1-year assessments. Analytes that were most highly associated with depressive symptoms included hepatocyte growth factor, insulin polypeptides, pregnancy-associated plasma protein-A and vascular endothelial growth factor. Separate regression models assessed contributions of past history of psychiatric illness, antidepressant or other psychotropic medicine, apolipoprotein E genotype, body mass index, serum glucose and cerebrospinal fluid (CSF) τ and amyloid levels, and none of these values significantly attenuated the main effects of the candidate analyte levels for depressive symptoms score. Ensemble machine learning with Random Forests found good accuracy (~80%) in classifying groups with and without depressive symptoms. These data begin to identify biochemical biomarkers of depressive symptoms in older adults that may be useful in investigations of pathophysiological mechanisms of depression in aging and neurodegenerative dementias and as targets of novel treatment approaches.

CSF amyloid {beta} 1-42 predicts cognitive decline in Parkinson disease.

OBJECTIVE: Cognitive decline associated with Parkinson disease (PD) is common and highly disabling. Biomarkers that help identify patients at risk for cognitive decline would be useful additions to the clinical management of the disease. METHODS: A total of 45 patients with PD were enrolled in this prospective cohort study and had at least 1 yearly longitudinal follow-up evaluation. CSF was collected at baseline and cognition was assessed at baseline and follow-up visits using the Mattis Dementia Rating Scale (DRS-2). CSF was tested for amyloid ß 1-42 (Aß(1-42)), p-tau(181p), and total tau levels using the Luminex xMAP platform. Mixed linear models were used to test for associations between baseline CSF biomarker levels and change in cognition over time. RESULTS: Lower baseline CSF Aß(1-42) was associated with more rapid cognitive decline. Subjects with CSF Aß(1-42) levels ≤192 pg/mL declined an average of 5.85 (95% confidence interval 2.11-9.58, p = 0.002) points per year more rapidly on the DRS-2 than subjects above that cutoff, after adjustment for age, disease duration, and baseline cognitive status. CSF total tau and p-tau(181p) levels were not significantly associated with cognitive decline. CONCLUSIONS: Reduced CSF Aß(1-42) was an independent predictor of cognitive decline in patients with PD. This observation is consistent with previous research showing that Alzheimer disease pathology contributes to cognitive impairment in PD. This biomarker may provide clinically useful prognostic information, particularly if combined with other risk factors for cognitive impairment in PD.

Validity of the MoCA and MMSE in the detection of MCI and dementia in Parkinson disease.

BACKGROUND: Due to the high prevalence of mild cognitive impairment (MCI) and dementia in Parkinson disease (PD), routine cognitive screening is important for the optimal management of patients with PD. The Montreal Cognitive Assessment (MoCA) is more sensitive than the commonly used Mini-Mental State Examination (MMSE) in detecting MCI and dementia in patients without PD, but its validity in PD has not been established. METHODS: A representative sample of 132 patients with PD at 2 movement disorders centers was administered the MoCA, MMSE, and a neuropsychological battery with operationalized criteria for deficits. MCI and PD dementia (PDD) criteria were applied by an investigator blinded to the MoCA and MMSE results. The discriminant validity of the MoCA and MMSE as screening and diagnostic instruments was ascertained. RESULTS: Approximately one third of the sample met diagnostic criteria for a cognitive disorder (12.9% PDD and 17.4% MCI). Mean (SD) MoCA and MMSE scores were 25.0 (3.8) and 28.1 (2.0). The overall discriminant validity for detection of any cognitive disorder was similar for the MoCA and the MMSE (receiver operating characteristic area under the curve [95% confidence interval]): MoCA (0.79 [0.72, 0.87]) and MMSE (0.76 [0.67, 0.85]), but as a screening instrument the MoCA (optimal cutoff point = 26/27, 64% correctly diagnosed, lack of ceiling effect) was superior to the MMSE (optimal cutoff point = 29/30, 54% correctly diagnosed, presence of ceiling effect). CONCLUSIONS: The Montreal Cognitive Assessment, but not the Mini-Mental State Examination, has adequate psychometric properties as a screening instrument for the detection of mild cognitive impairment or dementia in Parkinson disease. However, a positive screen using either instrument requires additional assessment due to suboptimal specificity at the recommended screening cutoff point.

Expression and correlation of hypoxia-inducible factor-1alpha, vascular endothelial growth factor and microvessel density in experimental rat hepatocarcinogenesis.

An experimental rat hepatocellular carcinoma (HCC) model was established using diethylnitrosamine and N-nitrosomorpholine to induce carcinogenesis in Sprague-Dawley rats. During hepatocarcinogenesis, seven rats were sacrificed at 0, 4, 8, 12 and 16 weeks and 10 rats were sacrificed at 20 weeks. The levels of hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) protein and mRNA were examined by immunohistochemistry, Western blot and semi-quantitative reverse transcriptase-polymerase chain reaction at different stages in the rat HCC model. Twenty weeks after induction of hepatocarcinogenesis, the expression of HIF-1alpha and VEGF protein and mRNA significantly increased compared with week 0. Microvessel density (MVD) increased considerably once liver cancer developed. There was a significant positive correlation between MVD and both HIF-1alpha and VEGF, and between HIF-1alpha and VEGF levels. These results suggest that HIF-1alpha and VEGF play important roles in tumour occurrence and development during rat hepatocarcinogenesis, possibly through promoting tumour angiogenesis.

Longitudinal decline in autopsy-defined frontotemporal lobar degeneration.

BACKGROUND: The natural history of patients with pathologically proven frontotemporal lobar degeneration (FTLD) is important from clinical and biologic perspectives, but is not well documented quantitatively. METHODS: We examine longitudinal decline in cognitive functioning in an autopsy-proven cohort of patients with the clinical diagnosis of a FTLD spectrum disorder or FTLD pathology using a panel of neuropsychological measures. Patients are categorized according to findings at autopsy into tau-positive FTLD, tau-negative FTLD, and frontal variant-Alzheimer disease (fvAD) subgroups. RESULTS: Patients decline significantly over time on all neuropsychological measures. Moreover, several measures differentiate between histopathologically distinct subgroups throughout the course of the disease process. This includes a significant double dissociation involving relative difficulty on a visual constructional measure in tau-positive patients compared to relatively impaired visual confrontation naming in tau-negative patients. Longitudinal measures of FAS naming fluency and animal naming fluency also distinguish tau-positive patients and tau-negative patients with FTLD from patients with fvAD. Other measures show significant decline but do not distinguish between histopathologic groups longitudinally. CONCLUSION: Our findings suggest different longitudinal patterns of cognitive decline in pathologically defined subgroups of patients. Measures consistently distinguishing between patient subgroups can be used to bolster diagnostic accuracy throughout the course of these diseases, while measures demonstrating undifferentiated longitudinal decline may serve as useful endpoints in treatment trials.

Factors associated with survival probability in autopsy-proven frontotemporal lobar degeneration.

OBJECTIVE: To examine the clinical and pathological factors associated with survival in autopsy-confirmed frontotemporal lobar degeneration (FTLD). METHODS: The final analysis cohort included 71 patients with pathologically proven FTLD, excluding patients with clinical motor neuron disease (MND), evaluated at the University of Pennsylvania or at the University of California, San Francisco. We assessed clinical and demographic features; cognitive functioning at presentation; genetic markers of disease; and graded anatomical distribution of tau, ubiquitin and amyloid pathology. RESULTS: The tau-negative group (n = 35) had a median survival time of 96 months (95% CI: 72-114 months), whereas the tau-positive group (n = 36) had a median survival time of 72 months (95% CI: 60-84 months). Patients with tau-positive pathology across all brain regions had shorter survival than those with tau-negative pathology in univariate Cox regression analyses (Hazard ratio of dying = 2.003, 95% CI = 1.209-3.318, p = 0.007). CONCLUSIONS: Tau-positive pathology represents a significant risk to survival in FTLD, whereas tau-negative pathology is associated with a longer survival time when clinical MND is excluded.

Patterns of neuropsychological impairment in frontotemporal dementia.

OBJECTIVE: To differentiate frontotemporal dementia (FTD) subtypes from each other and from probable Alzheimer disease (AD) using neuropsychological tests. METHODS: Patients with FTD and AD (n = 109) were studied with a comprehensive neuropsychological protocol at first contact. Data were subjected to a principal components analysis (PCA) to extract core neuropsychological features. A five-factor solution accounted for 72.89% of the variance and yielded factors related to declarative memory, working memory/visuoconstruction, processing speed/mental flexibility, lexical retrieval, and semantic memory. RESULTS: Between- and within-group analyses revealed that patients with AD obtain their lowest scores on tests of declarative memory while semantic dementia (SemD) patients are particularly disadvantaged on tests of semantic memory. On tests of processing speed/mental flexibility time to completion was faster for social comportment/dysexecutive (SOC/EXEC) patients, but these patients made more errors on some tests. Patients with corticobasal degeneration (CBD) and progressive nonfluent aphasia (PNFA) were impaired on tests of working memory. Logistic regression analyses using factor scores successfully assigned FTD subgroups and AD patients into their respective diagnostic categories. CONCLUSION: Patients with differing frontotemporal dementia phenotypes can be distinguished from each other and from Alzheimer disease using neuropsychological tests.

The ability of persons with Alzheimer disease (AD) to make a decision about taking an AD treatment.

OBJECTIVE: To examine the severity of impairments in the decision-making abilities (understanding, appreciation, reasoning, and choice) and competency to make a decision to use an Alzheimer disease (AD)-slowing medication in patients with AD and the relationships between these impairments, insight, and overall cognition. METHODS: Semistructured in-home interviews were conducted with 48 patients with very mild to moderate AD and 102 family caregivers of patients with mild to severe AD recruited from the Memory Disorders Clinic of an AD center. The interview measured performance on the decision-making abilities and three expert psychiatrists' judgment of competency based on their independent review of the patient interviews. RESULTS: There was considerable variation in patients' performance on the measures of decision-making abilities. Three expert raters found 19 of 48 (40%) of the subjects competent. Competent patients were more likely to show awareness of their symptoms, prognosis, and diagnosis. A sensitivity analysis suggests that a MMSE score is helpful in discriminating capacity from incapacity only when below 19 or above 23. CONCLUSIONS: Persons with mild to moderate Alzheimer disease (AD) have notable impairments in their ability to make an AD treatment decision, especially persons with moderate AD and persons who lack awareness of symptoms, prognosis, or diagnosis.

Nonbladder related symptoms in patients with interstitial cystitis.

PURPOSE: Clinical experience and epidemiological studies suggest that patients with interstitial cystitis have multiple nonbladder related symptoms. However, to our knowledge this finding has not been tested with a validated questionnaire and matched controls. With the University of Wisconsin scale, we compare the scores for patients with interstitial cystitis to those for control subjects. This validated questionnaire includes 7 bladder and 18 reference symptoms not related to the bladder. MATERIALS AND METHODS: A total of 35 female patients with interstitial cystitis and 35 age matched female controls completed the University of Wisconsin questionnaire. RESULTS: For the 7 bladder symptoms the difference between interstitial cystitis and control groups was extremely significant (p = 0.0001). Patients with interstitial cystitis had higher scores than controls for 2 reference symptoms, including other pelvic discomfort, backache, dizziness, chest pain, aches in joints, abdominal cramps, nausea, heart pounding and headache (p <0.01). However, they did not have higher scores for blind spots and/or blurred vision, numbness and/or tingling in fingers or toes, swollen ankles, feeling of suffocation, sore throat, cough, flu, nasal congestion and ringing in ears. The majority of patients with interstitial cystitis had a 0 score for all but 2 of the reference symptoms. CONCLUSIONS: Patients with interstitial cystitis had increased scores for 9 reference symptoms but did not indiscriminately report high scores for generalized complaints. This result suggests that in some cases of interstitial cystitis the pathophysiology may affect other organ systems besides the bladder. Alternatively, some of these symptoms may result from changes in sleep pattern or other factors associated with interstitial cystitis.

Purification, characterization, and gene cloning of purine nucleosidase from Ochrobactrum anthropi.

A bacterium, Ochrobactrum anthropi, produced a large amount of a nucleosidase when cultivated with purine nucleosides. The nucleosidase was purified to homogeneity. The enzyme has a molecular weight of about 170,000 and consists of four identical subunits. It specifically catalyzes the irreversible N-riboside hydrolysis of purine nucleosides, the K(m) values being 11.8 to 56.3 microM. The optimal activity temperature and pH were 50 degrees C and pH 4.5 to 6.5, respectively. Pyrimidine nucleosides, purine and pyrimidine nucleotides, NAD, NADP, and nicotinamide mononucleotide are not hydrolyzed by the enzyme. The purine nucleoside hydrolyzing activity of the enzyme was inhibited (mixed inhibition) by pyrimidine nucleosides, with K(i) and K(i)' values of 0.455 to 11.2 microM. Metal ion chelators inhibited activity, and the addition of Zn(2+) or Co(2+) restored activity. A 1.5-kb DNA fragment, which contains the open reading frame encoding the nucleosidase, was cloned, sequenced, and expressed in Escherichia coli. The deduced 363-amino-acid sequence including a 22-residue leader peptide is in agreement with the enzyme molecular mass and the amino acid sequences of NH(2)-terminal and internal peptides, and the enzyme is homologous to known nucleosidases from protozoan parasites. The amino acid residues forming the catalytic site and involved in binding with metal ions are well conserved in these nucleosidases.

High yield synthesis of nitriles by a new enzyme, phenylacetaldoxime dehydratase, from Bacillus sp. strain OxB-1.

3-Phenylpropionitrile was synthesized from Z-3-phenylpropionaldoxime (0.75 M) in a quantitative yield (98 g/l) by the use of cells of Escherichia coli JM 109/pOxD-90F, a transformant harboring a gene for a new enzyme, phenylacetaldoxime dehydratase, from Bacillus sp. strain OxB-1. Other arylalkyl- and alkyl-nitriles were also synthesized in high yields from the corresponding aldoximes. Moreover, 3-phenylpropionitrile was successfully synthesized by the recombinant cells in 70 and 100% yields from 0.1 M unpurified E/Z-3-phenylpropionaldoxime, which is spontaneously formed from 3-phenylpropionaldehyde and hydroxylamine in a butyl acetate/water biphasic system and aqueous phase, respectively.

[Studies on the chemical constituents from Tribulus terrestris].

AIM: To investigate the chemical constituents of the fruit of Tribulus terrestris J.. METHODS: Various chromatographic techniques were used to separate the chemical constituents. ESIMS, IR, 1HNMR, 13CNMR and HMBC were used to determine the structures of the isolated constituents. RESULTS: Two new compounds were isolated from the fruits of Tribulus terrestris J. and were identified as neohecogenin-3-O-beta-D-glucopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->4)-beta-D-galactopyranoside (I); neohecogenin-3-O-beta-D-glucopyranosyl (1-->4)-beta-D-galactopyranoside (II). CONCLUSION: Compounds I and II are new steroidal saponins.

Confidence of academic general internists and family physicians to teach ambulatory procedures.

OBJECTIVE: To evaluate and compare the readiness of academic general internal medicine physicians and academic family medicine physicians to perform and teach 13 common ambulatory procedures. DESIGN: Mailed survey. SETTING: Internal medicine and family medicine residency training programs associated with 35 medical schools in 9 eastern states. PARTICIPANTS: Convenience sample of full-time teaching faculty. MEASUREMENTS AND MAIN RESULTS: A total of 331 general internists and 271 family physicians returned completed questionnaires, with response rates of 57% and 65%, respectively. Academic generalists ranked most of the ambulatory procedures as important for primary care physicians to perform; however, they infrequently performed or taught many of the procedures. Overall, compared with family physicians, general internists performed and taught fewer procedures, received less training, and were less confident in their ability to teach these procedures. Physicians' confidence to teach a procedure was strongly associated with training to perform the procedure and performing or precepting a procedure at least 10 times per year. CONCLUSIONS: Many academic general internists do not perform or precept common adult ambulatory procedures. To ensure that residents have the opportunity to learn routine ambulatory procedures, training programs may need to recruit qualified faculty, train current faculty, or arrange for academic specialists or community physicians to teach these skills.

Confidence of graduating internal medicine residents to perform ambulatory procedures.

OBJECTIVE: To evaluate the training of graduating internal medicine residents to perform 13 common ambulatory procedures, 3 inpatient procedures, and 3 screening examinations. DESIGN: Self-administered descriptive survey. SETTING: Internal medicine training programs associated with 9 medical schools in the eastern United States. PARTICIPANTS: Graduating residents (N = 128); response rate, 60%. MEASUREMENTS AND MAIN RESULTS: The total number of procedures performed during residency, importance for primary care physicians to perform these procedures, confidence to perform these procedures, and helpfulness of rotations for learning procedures were assessed. The majority of residents performed only 2 of 13 outpatient procedures 10 or more times during residency: simple spirometry and minor wound suturing. For all other procedures, the median number performed was 5 or fewer. The percentage of residents attributing high importance to a procedure was significantly greater than the percentage reporting high confidence for 8 of 13 ambulatory procedures; for all inpatient procedures, residents reported significantly higher confidence than importance. Continuity clinic and block ambulatory rotations were not considered helpful for learning ambulatory procedures. CONCLUSIONS: Though residents in this sample considered most ambulatory procedures important for primary care physicians, they performed them infrequently, if at all, during residency and did not consider their continuity clinic experience helpful for learning these skills. Training programs need to address this deficiency by modifying the curriculum to ensure that these skills are taught to residents who anticipate a career in primary care medicine.

NAD(+)-dependent (S)-specific secondary alcohol dehydrogenase involved in stereoinversion of 3-pentyn-2-ol catalyzed by Nocardia fusca AKU 2123.

An NAD(+)-dependent alcohol dehydrogenase was purified to homogeneity from Nocardia fusca AKU 2123. The enzyme catalyzed (S)-specific oxidation of 3-pentyn-2-ol (PYOH), i.e., part of the stereoinversion reaction for the production of (R)-PYOH, which is a valuable chiral building block for pharmaceuticals, from the racemate. The enzyme used a broad variety of secondary alcohols including alkyl alcohols, alkenyl alcohols, acetylenic alcohols, and aromatic alcohols as substrates. The oxidation was (S)-isomer specific in every case. The K(m) and Vmax for (S)-PYOH and (S)-2-hexanol oxidation were 1.6 mM and 53 mumol/min/mg, and 0.33 mM and 130 mumol/min/mg, respectively. The enzyme also catalyzed stereoselective reduction of carbonyl compounds. (S)-2-Hexanol and ethyl (R)-4-chloro-3-hydroxybutanoate in high optical purity were produced from 2-hexanone and ethyl 4-chloro-3-oxobutanoate by the purified enzyme, respectively. The K(m) and Vmax for 2-hexanone reduction were 2.5 mM and 260 mumol/min/mg. The enzyme has a relative molecular mass of 150,000 and consists of four identical subunits. The NH2-terminal amino acid sequence of the enzyme shows similarity with those of the carbonyl reductase from Rhodococcus erythropolis and phenylacetaldehyde reductase from Corynebacterium sp.

Production of (R)-3-pentyn-2-ol through stereoinversion of racemic 3-pentyn-2-ol by Nocardia fusca AKU 2123.

Wet cells of Nocardia fusca AKU 2123 are good catalysts for the production of (R)-3-pentyn-2-ol (PYOH) from (RS)-PYOH through a stereoinversion reaction. Under optimal conditions (350 mM potassium phosphate buffer, pH 8.0, 30% (w/v) wet cells, 0.12% NADPH, 10% glucose, and 30 U/ml glucose dehydrogenase) (R)-PYOH of high optical purity (98.7% e.e.) was produced from 2% (v/v) (RS)-PYOH with a yield of 70.4% by 140 h incubation.