Enzymatic Synthesis of New Acetoacetate-Ursodeoxycholic Acid Hybrids as Potential Therapeutic Agents and Useful Synthetic Scaffolds as Well.

Ursodeoxycholic acid (UDCA) and acetoacetate are natural compounds present in the human intestine and blood, respectively. A number of studies highlighted that besides their well-known primary biological roles, both compounds possess the ability to influence a variety of cellular processes involved in the etiology of various diseases. These reasons suggested the potential of acetoacetate-UDCA hybrids as possible therapeutic agents and prompted us to develop a synthetic strategy to selectively derivatize the hydroxyl groups of the bile acid with acetoacetyl moieties. 3α-acetoacetoxy UDCA was obtained (60% isolated yield) via the regioselective transesterification of methyl acetoacetate with UDCA promoted by the Candida antarctica lipase B (CAL-B). 3α,7ß-bis-acetoacetoxy UDCA was obtained instead by thermal condensation of methyl acetoacetate and UDCA (80% isolated yield). This bis-adduct was finally converted to the 7ß-acetoacetoxy UDCA (82% isolated yield) via CAL-B catalyzed regioselective alcoholysis of the ester group on the 3α position. In order to demonstrate the value of the above new hybrids as UDCA-based scaffolds, 3α-acetoacetoxy UDCA was subjected to multicomponent Biginelli reaction with benzaldehyde and urea to obtain the corresponding 4-phenyl-3,4-dihydropyrimidin-2-(1H)-one derivative in 65% isolated yield.

Microwave-assisted enzymatic synthesis of geraniol esters in solvent-free systems: optimization of the reaction parameters, purification and characterization of the products, and biocatalyst reuse.

Various geraniol esters act as insect pheromones and display pharmacological activities, especially as neuroprotective agents. Therefore, the search for synthetic strategies alternative to traditional chemical synthesis could help designing ecofriendly routes for the preparation of such bioactive compounds. Hence, this work aims at the microwave-assisted enzymatic synthesis of geranyl esters in solvent-free systems. The process variables were optimized for the synthesis of geranyl acetoacetate, achieving 85% conversion after 60 min using a 1:5 substrates molar ratio (ester to geraniol), 80 °C and 8.4% of Lipozyme 435 lipase without removal of the co-produced methanol. On the other hand, a 95% conversion was reached after 30 min using 1:6 substrates molar ratio, 70 °C and 7% lipase in the presence of 5Å molecular sieves for the methanol capture. In addition, the lipase showed good reusability, maintaining the same activity for five reaction cycles. Finally, under the above optimized conditions, other geraniol esters were successfully synthetized such as the geranyl butyrate (98%), geranyl hexanoate (99%), geranyl octanoate (98%), and geranyl (R)-3-hydroxybutyrate (56%). These results demonstrate the microwave-assisted lipase-catalyzed transesterification in a solvent-free system as an excellent and sustainable catalytic methodology to produce geraniol esters.

Enzymatic diastereo- and enantioselective synthesis of α-alkyl-α,ß-dihydroxyketones.

An enzymatic strategy for the preparation of optically pure α-alkyl-α,ß-dihydroxyketones is reported. Homo- and cross-coupling reactions of α-diketones catalyzed by acetylacetoin synthase (AAS) produce a set of α-alkyl-α-hydroxy-ß-diketones (30-60%, ee 67-90%), which in turn are reduced regio-, diastereo-, and enantioselectively to the corresponding chiral α-alkyl-α,ß-dihydroxyketones (60-70%, ee >95%) using acetylacetoin reductase (AAR) as catalyst. Both enzymes are obtained from Bacillus licheniformis and used in a crude form. The relative syn stereochemistry of the enantiopure α,ß-dihydroxy products is assigned by NOE experiments, whereas their absolute configuration is determined by conversion of the selected 3,4-dihydroxy-3-methyl-pentan-2-one to the natural product (+)-citreodiol.

Cranial ultrasound scanning and prediction of outcome in newborns with congenital cytomegalovirus infection.

OBJECTIVE: To report the accuracy of ultrasound scanning (US) in predicting neurodevelopmental and sensorineural outcome in patients with congenital cytomegalovirus (CMV) infection. STUDY DESIGN: Fifty-seven neonates with congenital CMV infection underwent brain US and were observed prospectively for motor skills, developmental quotient, and hearing function. RESULTS: Abnormal results on US were found in 12 of 57 neonates. US lesions were more frequent in newborns with clinical and laboratory signs of congenital CMV infection at birth (10/18) than in newborns who had no symptoms at birth (2/39; P < .001). At least 1 sequela developed in all neonates with symptoms who had abnormal US results, whereas none of the neonates with symptoms who had normal US results had long-term sequelae (P < .001). In the population without symptoms, sensorineural hearing loss developed in 3 of 37 (8.1%) neonates with normal US results, whereas severe sequelae developed in 1 of 2 neonates with abnormal US results. CONCLUSIONS: A good correlation was found between cerebral US abnormalities and the prediction of outcome in newborns who were congenitally infected with CMV and had symptoms at birth. US could be performed as the first neuroimaging study in these newborns. Data are insufficient to permit any suggestions for the population without symptoms.

Neonatal cytomegalovirus blood load and risk of sequelae in symptomatic and asymptomatic congenitally infected newborns.

OBJECTIVE: Human cytomegalovirus (CMV) is a ubiquitous human-specific DNA virus and is the main cause of congenital virus infection in developed countries leading to psychomotor impairment and deafness. Diagnostic techniques for CMV detection have greatly improved during recent years with the advent of sophisticated serological and virological methods. The aim of the present study was to assess the diagnostic and prognostic value of detection and quantification of virus in neonatal blood samples of symptomatic and asymptomatic newborns with CMV congenital infection. METHODS: Between January 1997 and December 2003, we studied 99 newborns who were born to women with primary, recurrent, and undefined CMV infection during pregnancy. CMV congenital infection was identified by isolation of the virus in urine within the second week of life. Fifty-eight of 99 infants were infected and were assessed clinically for disease in the newborn period and classified as having symptomatic or asymptomatic infection on the basis of physical, instrumental, and laboratory findings. The infants were followed up from birth according to a protocol of the tertiary NICU at the University of Bologna in a prospective study of long-term sequelae of congenital infection. Forty-seven blood samples were obtained from 47 infants in the neonatal period: 34 were examined for pp65 antigenemia test and 44 for qualitative and quantitative polymerase chain reaction (PCR and qPCR). Sequelae at 12 months were evaluated in a group of 50 infants. RESULTS: Antigenemia was positive in only 10 of 34 samples of infected newborns (29.4% sensitivity). PCR was performed in 44 samples of infected newborns and was positive in all (100% sensitivity). qPCR showed a finding of > or =100 copies per 10(5) of polymorphonuclear leukocytes (PMNLs) in 39 of 44 samples; in the other 5 cases, the number of copies per 10(5) PMNLs was <100. Between symptomatic and asymptomatic newborns, the mean values of viral blood load determined by qPCR turned out to be significantly higher in symptomatic newborns. Mean values of neonatal blood viral load were statistically higher in newborns who developed sequelae than in those who did not. Of 20 children with a neonatal viral blood load of <1000 copies per 10(5) PMNLs, 19 did not develop sequelae (negative predictive value: 95%), whereas 2 of 3 with a viral blood load of >10,000 copies did develop sequelae. CONCLUSIONS: Different viremia value ranges are correlated to a different risk of sequelae: approximately 70% sequelae were found in newborns with a qPCR higher than 10,000 copies per 10(5) PMNLs. Low neonatal viral blood load detected by pp65 antigenemia test and qPCR was highly predictive of absence of sequelae: DNAemia <1000 copies per 10(5) PMNLs has a negative predictive value of 95%. As an independent predictive factor of outcome, neonatal viremia is another useful element for neonatal counseling and therapeutic choices in symptomatic and asymptomatic newborns.

Congenital infection with human herpesvirus 6 variant B associated with neonatal seizures and poor neurological outcome.

Human herpesvirus 6 (HHV 6) has neurotropic and neuroinvasive properties. The virus has been found in the cerebrospinal fluid of many children with aseptic meningoencephalitis. Intrauterine transmission has been documented by HHV 6 DNA detection in cord blood specimens of apparently healthy newborns and in fetuses following spontaneous abortions. A patient is described with early neonatal afebrile seizures resulting from a congenital HHV 6 variant B infection disclosed by repeated detection of viral genome by polymerase chain reaction (PCR) in cerebrospinal fluid in the first days of life. At follow-up, magnetic resonance imaging (MRI) studies disclosed hyperintensities in the periventricular white matter and basal ganglia, associated with cerebral atrophy. Further follow-up at 18 months revealed poor neurological outcome with mild neurodevelopmental retardation, strabismus and hypertonia of legs. This report provides evidence of neurological involvement after HHV 6 vertical transmission, and the association with neurological sequelae.

HLA DR13 and HCV vertical infection.

Risk factors affecting vertical hepatitis C virus (HCV) transmission are not completely known, if we exclude maternal HIV coinfection. We hypothesized that immunogenetic factors related to maternal or neonatal HLA profiles may affect HCV vertical transmission. HLA typing (microcytotoxicity assay on blood samples) was performed in 18 infants affected by vertically transmitted HCV infection and in 17 serum-reverted infants. (Serum-reversion is defined as antibody negative by 1 year of age and persistently HCV-RNA negative.) Moreover, HLA typing was performed in 20 mothers. Logistic regression analysis showed a significant negative association between children's HLA-DR13 antigens and risk of HCV vertical transmission (p < 0.01). This association persisted in a model including the maternal HIV status: HLA DR13 and maternal HIV coinfection showed a separate, opposite effect on vertical HCV infection (p < 0.01 and p < 0.001, respectively). The relative risk estimate for the ratio of not-infected to infected children in the presence of DR13 was 8.4 (95% confidence bounds, 1.1-60.8). Breast-feeding did not affect the risk of vertical HCV transmission. Maternal HLA profile did not relate to vertical infection. The present study reveals a significant association between HLA-DR13 and the likelihood of seroreversion in infants born to HCV-infected mothers. The findings of the present study could help in better understanding the pathogenesis of vertical HCV infection and in better identifying the cases at higher risk, which would be useful for the development of prevention strategies. It is possible that DR13 modulates the immune response to viruses, enhancing their clearance and, thus, in the case of HCV, exerting a protective role against the development of vertical infection.